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Sample records for proliferation marker mcm7

  1. Expression of MCM-3 and MCM-7 in Primary Cutaneous T-cell Lymphomas.

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    Jankowska-Konsur, Alina; Kobierzycki, Christopher; Reich, Adam; Grzegrzolka, Jedrzej; Maj, Joanna; Dziegiel, Piotr

    2015-11-01

    Primary cutaneous T-cell lymphomas is a group of rare non-Hodgkin lymphomas, originally affecting the skin. Increased proliferation activity is a hallmark of diverse tumors and the proliferation rate, measured by the expression of various markers has a predictive value regarding the malignancy course. The aim of the present study was to evaluate the prognostic value and the potential correlation between the expression of proliferation markers Ki-67, MCM-3 and MCM-7, and clinicopathological data for different types of primary cutaneous T-cell lymphomas. Immunohistochemical reactions were performed on paraffin blocks obtained from 90 patients with mycosis fungoides (MF) and 21 patients with other CTCL (oCTCL), in comparison to 19 patients with benign inflammatory dermatosis (lichen planus, eczema), serving as control. Statistically significant differences in the expression of Ki-67, MCM-3 and MCM-7 were observed between oCTCL vs. the control group (29% vs. 5%; 17% vs. 5%; 13% vs. 1.5%, respectively, ANOVA with Scheffé post-hoc test: pMCM-3 (r=0.83; pMCM-7 (r=0.84; pMCM-3 and MCM-7 (r=0.81, pMCM-3 expression was significantly higher in advanced compared to early stages (11% vs. 3% and 15.5% vs. 5.0%, respectively, Student's t-test: pMCM-3 and MCM-7 compared to benign inflammatory dermatoses (Student's t-test: pMCM-3 and MCM-7 than T1a (pMCM-3 expression in MF showed a positive relationship with both nodal and distant metastases (ANOVA with Scheffé post hoc test: pMCM-3 expression correlated with shorter survival in MF, although the latter did not reach statistical significance (10-year survival 0.38 vs. 0.82, p=0.02, and 0.46 vs. 0.81, p=0.06, respectively; log rank test). All studied proliferation markers may had predictive values regarding the disease severity and prognosis. Further studies are required to analyze their implementation into patient stratification and treatment process such that will improve prognosis in CTCL. Copyright© 2015 International

  2. MCM - 2 and Ki - 67 as proliferation markers in renal cell carcinoma: A quantitative and semi - quantitative analysis.

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    Mehdi, Muhammad Zain; Nagi, Abdul Hanan; Naseem, Nadia

    2016-01-01

    Fuhrman nuclear grade is the most important histological parameter to predict prognosis in a patient of renal cell carcinoma (RCC). However, it suffers from inter-observer and intra-observer variation giving rise to need of a parameter that not only correlates with nuclear grade but is also objective and reproducible. Proliferation is the measure of aggressiveness of a tumour and it is strongly correlated with Fuhrman nuclear grade, clinical survival and recurrence in RCC. Ki-67 is conventionally used to assess proliferation. Mini-chromosome maintenance 2 (MCM-2) is a lesser known marker of proliferation and identifies a greater proliferation faction. This study was designed to assess the prognostic significance of MCM-2 by comparing it with Fuhrman nuclear grade and Ki-67. n=50 cases of various ages, stages, histological subtypes and grades of RCC were selected for this study. Immunohistochemical staining using Ki-67(MIB-1, Mouse monoclonal antibody, Dako) and MCM-2 (Mouse monoclonal antibody, Thermo) was performed on the paraffin embedded blocks in the department of Morbid anatomy and Histopathology, University of Health Sciences, Lahore. Labeling indices (LI) were determined by two pathologists independently using quantitative and semi-quantitative analysis. Statistical analysis was carried out using SPSS 20.0. Kruskall-Wallis test was used to determine a correlation of proliferation markers with grade, and Pearson's correlate was used to determine correlation between the two proliferation markers. Labeling index of MCM-2 (median=24.29%) was found to be much higher than Ki-67(median=13.05%). Both markers were significantly related with grade (p=0.00; Kruskall-Wallis test). LI of MCM-2 was found to correlate significantly with LI of Ki-67(r=0.0934;p=0.01 with Pearson's correlate). Results of semi-quantitative analysis correlated well with quantitative analysis. Both Ki-67 and MCM-2 are markers of proliferation which are closely linked to grade. Therefore, they

  3. Fluoride Stimulates the Proliferation of Osteoclasts in vitro by Upregulating MCM3

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    Shengbin Bai

    2016-06-01

    Full Text Available We have previously shown that the expression of the minichromosome maintenance protein 3 (MCM3 gene was upregulated in lymphocytes of patients with skeletal fluorosis. We speculated that increased MCM3 expression may be contribute to osteopathy in patients with skeletal fluorosis. Here, we investigated the effect of fluoride on the proliferation of osteoclasts derived from RAW264.7 cells and the involvement of MCM3. Our MTT assays showed that 0.25 mM NaF markedly stimulated the proliferation of RAW264.7 cells. The RT-PCR and immunoblotting assays revealed that 0.25 mM NaF upregulated MCM3 expression in RAW264.7 cells. The MTT assays additionally demonstrated that stimulation with MCM3 potentiated the effect of fluorine on the proliferation of RAW264.7 cells. These results demonstrated that fluoride at clinical relevant concentration upregulates MCM3 expression in osteoclasts in vitro. We are currently conducting a series of experiments to examine whether increased MCM3 in osteoclasts indeed contributes to osteopathy in skeletal fluorosis.

  4. Comparison of minichromosome maintenance proteins (MCM-3, MCM-7) and metallothioneins (MT-I/II, MT-III) expression in relation to clinicopathological data in ovarian cancer.

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    Kobierzycki, Christopher; Pula, Bartosz; Skiba, Mateusz; Jablonska, Karolina; Latkowski, Krzysztof; Zabel, Maciej; Nowak-Markwitz, Ewa; Spaczynski, Marek; Kedzia, Witold; Podhorska-Okolow, Marzena; Dziegiel, Piotr

    2013-12-01

    Despite great progress in the understanding of ovarian cancer biology, clinicopathological data (i.e. grade, stage, histological type and residual disease after surgery) seem to be the most important prognostic factors. The present study aimed to investigate the relationship between expression of minichromosome maintenance proteins (MCM-3, MCM-7), metallothioneins (MT-I/II, MT-III), and Ki-67 in 103 ovarian cancer cases, mostly of the serous histological type. Statistical analysis revealed strong positive correlations in the expression of MCM-3 vs. Ki-67 (r=0.492), MCM-7 vs. Ki-67 (r=0.651), and MCM-3 vs. MCM-7 (r=0.515) (all pMCM-3 and Ki-67 with increasing grade of histological malignancy (p=0.0011, p=0.029, respectively). Regarding clinical progression, cytoplasmic MT-I/II expression was significantly higher in more advanced disease stages (III+IV vs. I+II; p=0.0247). Due to the correlations shown here, the determination of MCM proteins as proliferation markers of ovarian cancer, should be strongly considered.

  5. MCM-BP regulates unloading of the MCM2–7 helicase in late S phase

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    Nishiyama, Atsuya; Frappier, Lori; Méchali, Marcel

    2011-01-01

    Origins of DNA replication are licensed by recruiting MCM2–7 to assemble the prereplicative complex (pre-RC). How MCM2–7 is inactivated or removed from chromatin at the end of S phase is still unclear. Here, we show that MCM-BP can disassemble the MCM2–7 complex and might function as an unloader of MCM2–7 from chromatin. In Xenopus egg extracts, MCM-BP exists in a stable complex with MCM7, but is not associated with the MCM2–7 hexameric complex. MCM-BP accumulates in nuclei in late S phase, well after the loading of MCM2–7 onto chromatin. MCM-BP immunodepletion in Xenopus egg extracts inhibits replication-dependent MCM dissociation without affecting pre-RC formation and DNA replication. When excess MCM-BP is incubated with Xenopus egg extracts or immunopurified MCM2–7, it binds to MCM proteins and promotes disassembly of the MCM2–7 complex. Recombinant MCM-BP also releases MCM2–7 from isolated late-S-phase chromatin, but this activity is abolished when DNA replication is blocked. MCM-BP silencing in human cells also delays MCM dissociation in late S phase. We propose that MCM-BP plays a key role in the mechanism by which pre-RC is cleared from replicated DNA in vertebrate cells. PMID:21196493

  6. Alteration of proliferation and apoptotic markers in normal and premalignant tissue associated with prostate cancer

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    Ananthanarayanan, Vijayalakshmi; Deaton, Ryan J; Yang, Ximing J; Pins, Michael R; Gann, Peter H

    2006-01-01

    Molecular markers identifying alterations in proliferation and apoptotic pathways could be particularly important in characterizing high-risk normal or pre-neoplastic tissue. We evaluated the following markers: Ki67, Minichromosome Maintenance Protein-2 (Mcm-2), activated caspase-3 (a-casp3) and Bcl-2 to determine if they showed differential expression across progressive degrees of intraepithelial neoplasia and cancer in the prostate. To identify field effects, we also evaluated whether high-risk expression patterns in normal tissue were more common in prostates containing cancer compared to those without cancer (supernormal), and in histologically normal glands adjacent to a cancer focus as opposed to equivalent glands that were more distant. The aforementioned markers were studied in 13 radical prostatectomy (RP) and 6 cystoprostatectomy (CP) specimens. Tissue compartments representing normal, low grade prostatic intraepithelial neoplasia (LGPIN), high grade prostatic intraepithelial neoplasia (HGPIN), as well as different grades of cancer were mapped on H&E slides and adjacent sections were analyzed using immunohistochemistry. Normal glands within 1 mm distance of a tumor focus and glands beyond 5 mm were considered 'near' and 'far', respectively. Randomly selected nuclei and 40 × fields were scored by a single observer; basal and luminal epithelial layers were scored separately. Both Ki-67 and Mcm-2 showed an upward trend from normal tissue through HGPIN and cancer with a shift in proliferation from basal to luminal compartment. Activated caspase-3 showed a significant decrease in HGPIN and cancer compartments. Supernormal glands had significantly lower proliferation indices and higher a-casp3 expression compared to normal glands. 'Near' normal glands had higher Mcm-2 indices compared to 'far' glands; however, they also had higher a-casp3 expression. Bcl-2, which varied minimally in normal tissue, did not show any trend

  7. Prognostic significance of MCM2, Ki-67 and gelsolin in non-small cell lung cancer

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    Yang, Jun; Tan, Dongfeng; Ramnath, Nithya; Moysich, Kirsten B; Asch, Harold L; Swede, Helen; Alrawi, Sadir J; Huberman, Joel; Geradts, Joseph; Brooks, John SJ

    2006-01-01

    Uncontrolled proliferation and increased motility are hallmarks of neoplastic cells, therefore markers of proliferation and motility may be valuable in assessing tumor progression and prognosis. MCM2 is a member of the minichromosome maintenance (MCM) protein family. It plays critical roles in the initiation of DNA replication and in replication fork movement, and is intimately related to cell proliferation. Ki-67 is a proliferation antigen that is expressed during all but G 0 phases of the cell cycle. Gelsolin is an actin-binding protein that regulates the integrity of the actin cytoskeletal structure and facilitates cell motility. In this study, we assessed the prognostic significance of MCM2 and Ki-67, two markers of proliferation, and gelsolin, a marker of motility, in non-small cell lung cancer (NSCLC). 128 patients with pathologically confirmed, resectable NSCLC (stage I-IIIA) were included. Immunohistochemistry was utilized to measure the expressions of these markers in formalin-fixed, paraffin-embedded tumor tissues. Staining and scoring of MCM2, Ki-67 and gelsolin was independently performed. Analyses were performed to evaluate the prognostic significance of single expression of each marker, as well as the prognostic significance of composite expressions of MCM2 and gelsolin. Cox regression and Kaplan-Meier survival analysis were used for statistical analysis. Of the three markers, higher levels of gelsolin were significantly associated with an increased risk of death (adjusted RR = 1.89, 95% CI = 1.17–3.05, p = 0.01), and higher levels of MCM2 were associated with a non-significant increased risk of death (adjusted RR = 1.36, 95% CI = 0.84–2.20, p = 0.22). Combined, adjusted analyses revealed a significantly poor prognostic effect for higher expression of MCM2 and gelsolin compared to low expression of both biomarkers (RR = 2.32, 95% CI = 1.21–4.45, p = 0.01). Ki-67 did not display apparent prognostic effect in this study sample. The results suggest

  8. Clinical significance of MCM-2 and MCM-5 expression in colon cancer: association with clinicopathological parameters and tumor proliferative capacity.

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    Giaginis, Constantinos; Georgiadou, Maria; Dimakopoulou, Konstantina; Tsourouflis, Gerasimos; Gatzidou, Elisavet; Kouraklis, Gregorios; Theocharis, Stamatios

    2009-02-01

    Minichromosome maintenance (MCM) proteins are essential components of DNA replication, being related to cell proliferation, and serve as useful markers for cancer screening, surveillance, and prognosis. Our aim was to examine the clinical significance of MCM-2 and MCM-5 protein expression in colon cancer and to evaluate the association with various clinicopathological characteristics and tumor proliferative capacity. Immunohistochemical expression of MCM-2 and MCM-5 was performed on paraffin-embedded malignant tissue sections obtained from 96 patients with colon cancer. MCM-2 and MCM-5 expression was correlated with different clinicopathological characteristics, proliferative capacity (Ki-67 labeling index), and p53 cell-cycle regulator expression. MCM-2 and Ki-67 expression was significantly associated with the tumors' histological grade (P = 0.003), existence of nodular metastases (N) (P = 0.003 and P = 0.030, respectively), malignancy on adenoma (P = 0.029 and P = 0.024, respectively), and vascular invasion (P = 0.010 and P = 0.011, respectively). MCM-2 expression was additionally associated with Dukes' stage (P = 0.005). Significant positive relationships were found between the expression of MCM-2 or MCM-5 proteins and that of Ki-67 protein (r = 0.963, P-value characteristics examined. The current data suggest that MCM-2 protein expression is significantly associated with important clinicopathological characteristics for patients' management, being correlated with the cell proliferation state in colon cancer.

  9. Chronic DNA Replication Stress Reduces Replicative Lifespan of Cells by TRP53-Dependent, microRNA-Assisted MCM2-7 Downregulation.

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    Gongshi Bai

    2016-01-01

    Full Text Available Circumstances that compromise efficient DNA replication, such as disruptions to replication fork progression, cause a state known as DNA replication stress (RS. Whereas normally proliferating cells experience low levels of RS, excessive RS from intrinsic or extrinsic sources can trigger cell cycle arrest and senescence. Here, we report that a key driver of RS-induced senescence is active downregulation of the Minichromosome Maintenance 2-7 (MCM2-7 factors that are essential for replication origin licensing and which constitute the replicative helicase core. Proliferating cells produce high levels of MCM2-7 that enable formation of dormant origins that can be activated in response to acute, experimentally-induced RS. However, little is known about how physiological RS levels impact MCM2-7 regulation. We found that chronic exposure of primary mouse embryonic fibroblasts (MEFs to either genetically-encoded or environmentally-induced RS triggered gradual MCM2-7 repression, followed by inhibition of replication and senescence that could be accelerated by MCM hemizygosity. The MCM2-7 reduction in response to RS is TRP53-dependent, and involves a group of Trp53-dependent miRNAs, including the miR-34 family, that repress MCM expression in replication-stressed cells before they undergo terminal cell cycle arrest. miR-34 ablation partially rescued MCM2-7 downregulation and genomic instability in mice with endogenous RS. Together, these data demonstrate that active MCM2-7 repression is a physiologically important mechanism for RS-induced cell cycle arrest and genome maintenance on an organismal level.

  10. The effects of oligomerization on Saccharomyces cerevisiae Mcm4/6/7 function

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    Davey Megan J

    2010-09-01

    Full Text Available Abstract Background Minichromosome maintenance proteins (Mcm 2, 3, 4, 5, 6 and 7 are related by sequence and form a variety of complexes that unwind DNA, including Mcm4/6/7. A Mcm4/6/7 trimer forms one half of the Mcm2-7 hexameric ring and can be thought of as the catalytic core of Mcm2-7, the replicative helicase in eukaryotic cells. Oligomeric analysis of Mcm4/6/7 suggests that it forms a hexamer containing two Mcm4/6/7 trimers, however, under certain conditions trimeric Mcm4/6/7 has also been observed. The functional significance of the different Mcm4/6/7 oligomeric states has not been assessed. The results of such an assessment would have implications for studies of both Mcm4/6/7 and Mcm2-7. Results Here, we show that Saccharomyces cerevisiae Mcm4/6/7 reconstituted from individual subunits exists in an equilibrium of oligomeric forms in which smaller oligomers predominate in the absence of ATP. In addition, we found that ATP, which is required for Mcm4/6/7 activity, shifts the equilibrium towards larger oligomers, likely hexamers of Mcm4/6/7. ATPγS and to a lesser extent ADP also shift the equilibrium towards hexamers. Study of Mcm4/6/7 complexes containing mutations that interfere with the formation of inter-subunit ATP sites (arginine finger mutants indicates that full activity of Mcm4/6/7 requires all of its ATP sites, which are formed in a hexamer and not a trimer. In keeping with this observation, Mcm4/6/7 binds DNA as a hexamer. Conclusions The minimal functional unit of Mcm4/6/7 is a hexamer. One of the roles of ATP binding by Mcm4/6/7 may be to stabilize formation of hexamers.

  11. Open-ringed structure of the Cdt1-Mcm2-7 complex as a precursor of the MCM double hexamer.

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    Zhai, Yuanliang; Cheng, Erchao; Wu, Hao; Li, Ningning; Yung, Philip Yuk Kwong; Gao, Ning; Tye, Bik-Kwoon

    2017-03-01

    The minichromosome maintenance complex (MCM) hexameric complex (Mcm2-7) forms the core of the eukaryotic replicative helicase. During G1 phase, two Cdt1-Mcm2-7 heptamers are loaded onto each replication origin by the origin-recognition complex (ORC) and Cdc6 to form an inactive MCM double hexamer (DH), but the detailed loading mechanism remains unclear. Here we examine the structures of the yeast MCM hexamer and Cdt1-MCM heptamer from Saccharomyces cerevisiae. Both complexes form left-handed coil structures with a 10-15-Å gap between Mcm5 and Mcm2, and a central channel that is occluded by the C-terminal domain winged-helix motif of Mcm5. Cdt1 wraps around the N-terminal regions of Mcm2, Mcm6 and Mcm4 to stabilize the whole complex. The intrinsic coiled structures of the precursors provide insights into the DH formation, and suggest a spring-action model for the MCM during the initial origin melting and the subsequent DNA unwinding.

  12. Archaeal MCM Proteins as an Analog for the Eukaryotic Mcm2–7 Helicase to Reveal Essential Features of Structure and Function

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    Miller, Justin M.; Enemark, Eric J.

    2015-01-01

    In eukaryotes, the replicative helicase is the large multisubunit CMG complex consisting of the Mcm2–7 hexameric ring, Cdc45, and the tetrameric GINS complex. The Mcm2–7 ring assembles from six different, related proteins and forms the core of this complex. In archaea, a homologous MCM hexameric ring functions as the replicative helicase at the replication fork. Archaeal MCM proteins form thermostable homohexamers, facilitating their use as models of the eukaryotic Mcm2–7 helicase. Here we review archaeal MCM helicase structure and function and how the archaeal findings relate to the eukaryotic Mcm2–7 ring. PMID:26539061

  13. Comparison between immunohistochemical expression of Ki-67 and MCM-3 in major salivary gland epithelial tumors in children and adolescents. Preliminary study.

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    Zieliński, Rafał; Kobos, Jozef; Zakrzewska, Anna

    While Ki-67 expression is frequently used as an indicator of tumor cell proliferation, alternative markers have also been proposed. Possible alternative indicators of proliferation are the minichromosome maintenance (MCM) proteins, whose levels are inversely associated with tumor cell differentiation. The aim of this preliminary study was to compare the levels of Ki-67 and MCM-3 expression in major salivary gland epithelial tumors in all children and adolescents who underwent surgery in our department in the years 2009-2014. The histopathological diagnosis of the subjects was reviewed, as well as the expression of Ki-67 and MCM-3 in post-op specimens of the tumors. The normality of data was checked with the Shapiro-Wilk test. The t test for independent variables or the U test was used as appropriate to determine statistically significant differences in the expression of Ki-67 and MCM-3. Five cases of pleomorphic adenoma, one of myoepithelioma, one of basal cell adenoma and one of mucoepidermoid carcinoma were identified. Significantly greater MCM-3 than Ki-67 expression was observed in every case. The results of our preliminary study emphasize the need for future research on MCM-3 as a sensitive proliferation marker, providing an alternative to Ki-67, in cases of various major salivary gland epithelial tumors in children and adolescents.

  14. Binding of MCM-interacting proteins to ATP-binding site in MCM6

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    Hosoi A

    2016-03-01

    Full Text Available Atsutoshi Hosoi, Taku Sakairi, Yukio Ishimi Graduate School of Science and Engineering, Ibaraki University, Mito, Ibaraki, Japan Abstract: The function of MCM2–7 complex that is a DNA helicase in DNA replication may be regulated by various MCM-interacting proteins, including CDC45, RPA, TIM, TIPIN, Claspin, MCM10, and MCM-BP. It has been shown by immunoprecipitation that human MCM6 interacts with all these proteins in coexpressed insect cells. To determine the region in MCM6 to interact with these proteins, we prepared various truncated forms of MCM6 and examined the interaction of these MCM6 fragments with the MCM-interacting proteins. All these proteins bound to C-terminal half of MCM6, and CDC45, RPA2, TIM, TIPIN, MCM-BP, and MCM10 bound to the fragments containing ATP-binding motifs. CDC45 and RPA2 bound to the smallest fragment containing Walker motif A. Only MCM-BP is bound to the N-terminal half of MCM6. Site-directed mutagenesis study suggests that hydrophobic interaction is involved in the interaction of MCM6 with CDC45 and TIM. These results suggest a possibility that MCM-interacting proteins regulate MCM2–7 function by modulating the ATP-binding ability of the MCM2–7. Keywords: DNA helicase, DNA replication, checkpoint, MCM2–7 proteins

  15. Mcm2 phosphorylation and the response to replicative stress

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    Stead Brent E

    2012-05-01

    Full Text Available Abstract Background The replicative helicase in eukaryotic cells is comprised of minichromosome maintenance (Mcm proteins 2 through 7 (Mcm2-7 and is a key target for regulation of cell proliferation. In addition, it is regulated in response to replicative stress. One of the protein kinases that targets Mcm2-7 is the Dbf4-dependent kinase Cdc7 (DDK. In a previous study, we showed that alanine mutations of the DDK phosphorylation sites at S164 and S170 in Saccharomyces cerevisiae Mcm2 result in sensitivity to caffeine and methyl methanesulfonate (MMS leading us to suggest that DDK phosphorylation of Mcm2 is required in response to replicative stress. Results We show here that a strain with the mcm2 allele lacking DDK phosphorylation sites (mcm2AA is also sensitive to the ribonucleotide reductase inhibitor, hydroxyurea (HU and to the base analogue 5-fluorouracil (5-FU but not the radiomimetic drug, phleomycin. We screened the budding yeast non-essential deletion collection for synthetic lethal interactions with mcm2AA and isolated deletions that include genes involved in the control of genome integrity and oxidative stress. In addition, the spontaneous mutation rate, as measured by mutations in CAN1, was increased in the mcm2AA strain compared to wild type, whereas with a phosphomimetic allele (mcm2EE the mutation rate was decreased. These results led to the idea that the mcm2AA strain is unable to respond properly to DNA damage. We examined this by screening the deletion collection for suppressors of the caffeine sensitivity of mcm2AA. Deletions that decrease spontaneous DNA damage, increase homologous recombination or slow replication forks were isolated. Many of the suppressors of caffeine sensitivity suppressed other phenotypes of mcm2AA including sensitivity to genotoxic drugs, the increased frequency of cells with RPA foci and the increased mutation rate. Conclusions Together these observations point to a role for DDK-mediated phosphorylation

  16. Interactions of the human MCM-BP protein with MCM complex components and Dbf4.

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    Tin Nguyen

    Full Text Available MCM-BP was discovered as a protein that co-purified from human cells with MCM proteins 3 through 7; results which were recapitulated in frogs, yeast and plants. Evidence in all of these organisms supports an important role for MCM-BP in DNA replication, including contributions to MCM complex unloading. However the mechanisms by which MCM-BP functions and associates with MCM complexes are not well understood. Here we show that human MCM-BP is capable of interacting with individual MCM proteins 2 through 7 when co-expressed in insect cells and can greatly increase the recovery of some recombinant MCM proteins. Glycerol gradient sedimentation analysis indicated that MCM-BP interacts most strongly with MCM4 and MCM7. Similar gradient analyses of human cell lysates showed that only a small amount of MCM-BP overlapped with the migration of MCM complexes and that MCM complexes were disrupted by exogenous MCM-BP. In addition, large complexes containing MCM-BP and MCM proteins were detected at mid to late S phase, suggesting that the formation of specific MCM-BP complexes is cell cycle regulated. We also identified an interaction between MCM-BP and the Dbf4 regulatory component of the DDK kinase in both yeast 2-hybrid and insect cell co-expression assays, and this interaction was verified by co-immunoprecipitation of endogenous proteins from human cells. In vitro kinase assays showed that MCM-BP was not a substrate for DDK but could inhibit DDK phosphorylation of MCM4,6,7 within MCM4,6,7 or MCM2-7 complexes, with little effect on DDK phosphorylation of MCM2. Since DDK is known to activate DNA replication through phosphorylation of these MCM proteins, our results suggest that MCM-BP may affect DNA replication in part by regulating MCM phosphorylation by DDK.

  17. Interactions of the human MCM-BP protein with MCM complex components and Dbf4.

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    Nguyen, Tin; Jagannathan, Madhav; Shire, Kathy; Frappier, Lori

    2012-01-01

    MCM-BP was discovered as a protein that co-purified from human cells with MCM proteins 3 through 7; results which were recapitulated in frogs, yeast and plants. Evidence in all of these organisms supports an important role for MCM-BP in DNA replication, including contributions to MCM complex unloading. However the mechanisms by which MCM-BP functions and associates with MCM complexes are not well understood. Here we show that human MCM-BP is capable of interacting with individual MCM proteins 2 through 7 when co-expressed in insect cells and can greatly increase the recovery of some recombinant MCM proteins. Glycerol gradient sedimentation analysis indicated that MCM-BP interacts most strongly with MCM4 and MCM7. Similar gradient analyses of human cell lysates showed that only a small amount of MCM-BP overlapped with the migration of MCM complexes and that MCM complexes were disrupted by exogenous MCM-BP. In addition, large complexes containing MCM-BP and MCM proteins were detected at mid to late S phase, suggesting that the formation of specific MCM-BP complexes is cell cycle regulated. We also identified an interaction between MCM-BP and the Dbf4 regulatory component of the DDK kinase in both yeast 2-hybrid and insect cell co-expression assays, and this interaction was verified by co-immunoprecipitation of endogenous proteins from human cells. In vitro kinase assays showed that MCM-BP was not a substrate for DDK but could inhibit DDK phosphorylation of MCM4,6,7 within MCM4,6,7 or MCM2-7 complexes, with little effect on DDK phosphorylation of MCM2. Since DDK is known to activate DNA replication through phosphorylation of these MCM proteins, our results suggest that MCM-BP may affect DNA replication in part by regulating MCM phosphorylation by DDK.

  18. MCM-2 expression differentiates potentially malignant verrucous lesions from oral carcinomas.

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    Niranjan, Kochli Channappa; Sarathy, Niharika Abhay; Alrani, Devendra

    2018-03-13

    Mcm-2 is a biomarker belonging to Mcm family of proteins which has rarely been used in oral potentially malignant and malignant lesions of the verrucous type. The objective of this study is to assess the expression of Mcm-2 in Normal Oral Mucosa (NM), Verrucous Hyperplasia (VH), Verrucous Carcinoma (VC) and Oral Squamous Cell Carcinoma (OSCC) and compare it with the clinicopathological characteristics. A total of 70 formalin fixed paraffin embedded tissue samples (10 cases of Normal Mucosa NM- Group A, 10 cases of Verrucous Hyperplasia- VH without Dysplasia- Group B, 10 cases of Verrucous Hyperplasia- VH with Dysplasia- Group C, 20 cases of Verrucous Carcinoma VC-Group D, 20 cases of Oral Squamous Cell Carcinoma OSCC- Group E) were subjected to immunohistochemistry with Mcm-2 antibody. Statistical analysis was carried out with various tests like ANOVA, Tukey HSD, Chi-Square and Shapiro-Wilk test by using the SPSS software. There was a significant difference in Mcm-2 expression with quantitative analysis among all the groups (p Mcm-2 may be a sensitive proliferation marker in oral potentially malignant and malignant lesions which may be useful for differentiating between VH with/ without dysplasia, VC and OSCC. Copyright © 2018. Published by Elsevier Inc.

  19. Replication protein A in nonearly ovarian adenocarcinomas: correlation with MCM-2, MCM-5, Ki-67 index and prognostic significance.

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    Levidou, Georgia; Ventouri, Kiriaki; Nonni, Afroditi; Gakiopoulou, Hariklia; Bamias, Aristotle; Sotiropoulou, Maria; Papaspirou, Irene; Dimopoulos, Meletios A; Patsouris, Efstratios; Korkolopoulou, Penelope

    2012-07-01

    Replication protein A (RPA) is an ssDNA-binding protein required for the initiation of DNA replication and the stabilization of ssDNA. Collaboration with several molecules, that is, the MCM2-7 complex, has been suggested to be imperative for its multifaceted role. In this study, we investigated the immunohistochemical expression of the RPA2 subunit in correlation with the MCM-2 and MCM-5 and Ki67 index, and assessed its prognostic significance in 76 patients with nonearly ovarian adenocarcinomas, the majority of whom had a serous histotype. RPA2 protein expression was observed in all cases, whereas the staining intensity varied from weak to strong. RPA2 expression was correlated with the tumor stage in the entire cohort and in serous tumors (P=0.0053 in both relationships). Moreover, RPA2 immunoexpression was positively correlated with MCM-2 (P=0.0001) and MCM-5 (P0.10). In multivariate survival analysis, RPA2 expression emerged as an independent predictor of adverse outcome (PMCM-2 and MCM-5 expression and when analysis was restricted to serous carcinomas (P=0.004). Our results further support the interrelation of RPA2 protein with MCM-2 and MCM-5 in OCs. Moreover, RPA2 protein may play an important role in ovarian tumorigenesis, and may serve as a useful independent molecular marker for stratifying patients with OC in terms of prognosis.

  20. Mcm3 replicative helicase mutation impairs neuroblast proliferation and memory in Drosophila.

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    Blumröder, R; Glunz, A; Dunkelberger, B S; Serway, C N; Berger, C; Mentzel, B; de Belle, J S; Raabe, T

    2016-09-01

    In the developing Drosophila brain, a small number of neural progenitor cells (neuroblasts) generate in a co-ordinated manner a high variety of neuronal cells by integration of temporal, spatial and cell-intrinsic information. In this study, we performed the molecular and phenotypic characterization of a structural brain mutant called small mushroom bodies (smu), which was isolated in a screen for mutants with altered brain structure. Focusing on the mushroom body neuroblast lineages we show that failure of neuroblasts to generate the normal number of mushroom body neurons (Kenyon cells) is the major cause of the smu phenotype. In particular, the premature loss of mushroom body neuroblasts caused a pronounced effect on the number of late-born Kenyon cells. Neuroblasts showed no obvious defects in processes controlling asymmetric cell division, but generated less ganglion mother cells. Cloning of smu uncovered a single amino acid substitution in an evolutionarily conserved protein interaction domain of the Minichromosome maintenance 3 (Mcm3) protein. Mcm3 is part of the multimeric Cdc45/Mcm/GINS (CMG) complex, which functions as a helicase during DNA replication. We propose that at least in the case of mushroom body neuroblasts, timely replication is not only required for continuous proliferation but also for their survival. The absence of Kenyon cells in smu reduced learning and early phases of conditioned olfactory memory. Corresponding to the absence of late-born Kenyon cells projecting to α'/β' and α/β lobes, smu is profoundly defective in later phases of persistent memory. © 2016 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

  1. Screening for proteins interacting with MCM7 in human lung cancer library using yeast two hybrid system

    Directory of Open Access Journals (Sweden)

    Yuchen HAN

    2008-08-01

    Full Text Available Background and objective MCM7 is a subunit of the MCM complex that plays a key role in DNA replication initiation. But little is known about its interaction proteins. In this study yeast two hybrid screening was used to identify the MCM7 interacting proteins. Methods Yeast expression vector containing human full length MCM7-pGBKT7 plasmid was constructed, and with a library of cDNAs from human lung cancer-pACT2 plasmid was transformed into yeast strain AH109, and was electively grew in X-a-gal auxotrophy medium SD/-Trp-Leu-His-Ade, and the blue colonies were picked up, the plasmid of the yeast colonies was extracted , and transformed into E. Coli to extract DNA and performed sequence analysis. Results Eleven proteins were identified which could specifically interact with MCM7 proteins, among these five were cytoskeleton proteins, six were enzymes, kinases and related receptors. Conclusion The investigation provides functional clues for further exploration of MCM7 gene.

  2. Functional interaction between the glucocorticoid receptor and GANP/MCM3AP

    International Nuclear Information System (INIS)

    Osman, Waffa; Laine, Sanna; Zilliacus, Johanna

    2006-01-01

    Glucocorticoids are widely used to treat inflammatory diseases but have a number of side effects that partly are connected to inhibition of cell proliferation. Glucocorticoids mediated their action by binding to the glucocorticoid receptor. In the present study, we have identified by two-hybrid screens the germinal center-associated protein (GANP) and MCM3-associated protein (MCM3AP), a splicing variant of GANP, as glucocorticoid receptor interacting proteins. GANP and MCM3AP can bind to the MCM3 protein involved in initiation of DNA replication. Glutathione-S-transferase-pull-down and co-immunoprecipitation assays showed that the C-terminal domain of GANP, encompassing MCM3AP, interacts with the ligand-binding domain of the glucocorticoid receptor. Characterization of the intracellular localization of GANP revealed that GANP is shuttling between the nucleus and the cytoplasm. Furthermore, we show that glucocorticoids are unable to inhibit DNA replication in HeLa cells overexpressing MCM3AP suggesting a role for both glucocorticoid receptor and GANP/MCM3AP in regulating cell proliferation

  3. Nuclear localization of Schizosaccharomyces pombe Mcm2/Cdc19p requires MCM complex assembly.

    Science.gov (United States)

    Pasion, S G; Forsburg, S L

    1999-12-01

    The minichromosome maintenance (MCM) proteins MCM2-MCM7 are conserved eukaryotic replication factors that assemble in a heterohexameric complex. In fission yeast, these proteins are nuclear throughout the cell cycle. In studying the mechanism that regulates assembly of the MCM complex, we analyzed the cis and trans elements required for nuclear localization of a single subunit, Mcm2p. Mutation of any single mcm gene leads to redistribution of wild-type MCM subunits to the cytoplasm, and this redistribution depends on an active nuclear export system. We identified the nuclear localization signal sequences of Mcm2p and showed that these are required for nuclear targeting of other MCM subunits. In turn, Mcm2p must associate with other MCM proteins for its proper localization; nuclear localization of MCM proteins thus requires assembly of MCM proteins in a complex. We suggest that coupling complex assembly to nuclear targeting and retention ensures that only intact heterohexameric MCM complexes remain nuclear.

  4. Analysis of Mcm2-7 chromatin binding during anaphase and in the transition to quiescence in fission yeast

    International Nuclear Information System (INIS)

    Namdar, Mandana; Kearsey, Stephen E.

    2006-01-01

    Mcm2-7 proteins are generally considered to function as a heterohexameric complex, providing helicase activity for the elongation step of DNA replication. These proteins are loaded onto replication origins in M-G1 phase in a process termed licensing or pre-replicative complex formation. It is likely that Mcm2-7 proteins are loaded onto chromatin simultaneously as a pre-formed hexamer although some studies suggest that subcomplexes are recruited sequentially. To analyze this process in fission yeast, we have compared the levels and chromatin binding of Mcm2-7 proteins during the fission yeast cell cycle. Mcm subunits are present at approximately 1 x 10 4 molecules/cell and are bound with approximately equal stoichiometry on chromatin in G1/S phase cells. Using a single cell assay, we have correlated the timing of chromatin association of individual Mcm subunits with progression through mitosis. This showed that Mcm2, 4 and 7 associate with chromatin at about the same stage of anaphase, suggesting that licensing involves the simultaneous binding of these subunits. We also examined Mcm2-7 chromatin association when cells enter a G0-like quiescent state. Chromatin binding is lost in this transition in a process that does not require DNA replication or the selective degradation of specific subunits

  5. A unique binding mode enables MCM2 to chaperone histones H3-H4 at replication forks

    DEFF Research Database (Denmark)

    Huang, Hongda; Strømme, Caroline B; Saredi, Giulia

    2015-01-01

    During DNA replication, chromatin is reassembled by recycling of modified old histones and deposition of new ones. How histone dynamics integrates with DNA replication to maintain genome and epigenome information remains unclear. Here, we reveal how human MCM2, part of the replicative helicase......, chaperones histones H3-H4. Our first structure shows an H3-H4 tetramer bound by two MCM2 histone-binding domains (HBDs), which hijack interaction sites used by nucleosomal DNA. Our second structure reveals MCM2 and ASF1 cochaperoning an H3-H4 dimer. Mutational analyses show that the MCM2 HBD is required...... for MCM2-7 histone-chaperone function and normal cell proliferation. Further, we show that MCM2 can chaperone both new and old canonical histones H3-H4 as well as H3.3 and CENPA variants. The unique histone-binding mode of MCM2 thus endows the replicative helicase with ideal properties for recycling...

  6. A unique binding mode enables MCM2 to chaperone histones H3-H4 at replication forks.

    Science.gov (United States)

    Huang, Hongda; Strømme, Caroline B; Saredi, Giulia; Hödl, Martina; Strandsby, Anne; González-Aguilera, Cristina; Chen, Shoudeng; Groth, Anja; Patel, Dinshaw J

    2015-08-01

    During DNA replication, chromatin is reassembled by recycling of modified old histones and deposition of new ones. How histone dynamics integrates with DNA replication to maintain genome and epigenome information remains unclear. Here, we reveal how human MCM2, part of the replicative helicase, chaperones histones H3-H4. Our first structure shows an H3-H4 tetramer bound by two MCM2 histone-binding domains (HBDs), which hijack interaction sites used by nucleosomal DNA. Our second structure reveals MCM2 and ASF1 cochaperoning an H3-H4 dimer. Mutational analyses show that the MCM2 HBD is required for MCM2-7 histone-chaperone function and normal cell proliferation. Further, we show that MCM2 can chaperone both new and old canonical histones H3-H4 as well as H3.3 and CENPA variants. The unique histone-binding mode of MCM2 thus endows the replicative helicase with ideal properties for recycling histones genome wide during DNA replication.

  7. Minichromosome maintenance helicase paralog MCM9 is dispensible for DNA replication but functions in germ-line stem cells and tumor suppression.

    Science.gov (United States)

    Hartford, Suzanne A; Luo, Yunhai; Southard, Teresa L; Min, Irene M; Lis, John T; Schimenti, John C

    2011-10-25

    Effective DNA replication is critical to the health and reproductive success of organisms. The six MCM2-7 proteins, which form the replicative helicase, are essential for high-fidelity replication of the genome. Many eukaryotes have a divergent paralog, MCM9, that was reported to be essential for loading MCM2-7 onto replication origins in the Xenopus oocyte extract system. To address the in vivo role of mammalian MCM9, we created and analyzed the phenotypes of mice with various mutations in Mcm9 and an intronic DNA replication-related gene Asf1a. Ablation of Mcm9 was compatible with cell proliferation and mouse viability, showing that it is nonessential for MCM2-7 loading or DNA replication. Mcm9 mutants underwent p53-independent embryonic germ-cell depletion in both sexes, with males also exhibiting defective spermatogonial stem-cell renewal. MCM9-deficient cells had elevated genomic instability and defective cell cycle reentry following replication stress, and mutant animals were prone to sex-specific cancers, most notably hepatocellular carcinoma in males. The phenotypes of mutant mice and cells suggest that MCM9 evolved a specialized but nonessential role in DNA replication or replication-linked quality-control mechanisms that are especially important for germ-line stem cells, and also for tumor suppression and genome maintenance in the soma.

  8. Maspin and MCM2 immunoprofiling in salivary gland carcinomas

    Directory of Open Access Journals (Sweden)

    Helmy Iman M

    2011-09-01

    Full Text Available Abstract Background The pathogenesis of salivary gland carcinomas is very complex and prognostic markers are difficult to find in these carcinomas of which the different subtypes have varying malignant potential. The study was conducted to examine the cellular distribution of maspin and MCM2 in salivary gland carcinomas and their value to predict lymph node metastasis. Materials and methods Fifty three paraffin blocks of different lesions (15 muco-epidermoid carcinoma, 14 adenoid cystic carcinoma, 3 epi-myoepithelial carcinoma, 5 salivary duct carcinoma, 5 malignant pleomorphic adenoma, 6 polymorphous low grade adenocarcinoma and 5 acinic cell carcinoma were prepared for immunohistochemical staining with maspin and MCM2 antibodies. ANOVA and Pearson correlation tests were used for the statistical analysis of the results. Results All salivary gland carcinomas express maspin and MCM2 with variable cellular localization. There was a significant difference in the expression of each antibody between mucoepidermoid carcinoma, adenoid cystic carcinoma and polymorphous low grade adenocarcinoma. No association was found between examined markers and lymph node metastasis. Conclusions Salivary gland carcinomas express maspin and MCM2 with variable levels and cellular localization, consisting important markers of biological behavior in these tumors. The level of MCM2 expression can be used in the differential diagnosis of adenoid cystic carcinoma and polymorphous low grade adenocarcinoma. Further study with large sample size is recommended to assess their value in prediction of lymph node metastasis.

  9. The fission yeast minichromosome maintenance (MCM)-binding protein (MCM-BP), Mcb1, regulates MCM function during prereplicative complex formation in DNA replication.

    Science.gov (United States)

    Santosa, Venny; Martha, Sabrina; Hirose, Noriaki; Tanaka, Katsunori

    2013-03-08

    The minichromosome maintenance (MCM) complex is a replicative helicase, which is essential for chromosome DNA replication. In recent years, the identification of a novel MCM-binding protein (MCM-BP) in most eukaryotes has led to numerous studies investigating its function and its relationship to the MCM complex. However, the mechanisms by which MCM-BP functions and associates with MCM complexes are not well understood; in addition, the functional role of MCM-BP remains controversial and may vary between model organisms. The present study aims to elucidate the nature and biological function of the MCM-BP ortholog, Mcb1, in fission yeast. The Mcb1 protein continuously interacts with MCM proteins during the cell cycle in vivo and can interact with any individual MCM subunit in vitro. To understand the detailed characteristics of mcb1(+), two temperature-sensitive mcb1 gene mutants (mcb1(ts)) were isolated. Extensive genetic analysis showed that the mcb1(ts) mutants were suppressed by a mcm5(+) multicopy plasmid and displayed synthetic defects with many S-phase-related gene mutants. Moreover, cyclin-dependent kinase modulation by Cig2 repression or Rum1 overproduction suppressed the mcb1(ts) mutants, suggesting the involvement of Mcb1 in pre-RC formation during DNA replication. These data are consistent with the observation that Mcm7 loading onto replication origins is reduced and S-phase progression is delayed in mcb1(ts) mutants. Furthermore, the mcb1(ts) mutation led to the redistribution of MCM subunits to the cytoplasm, and this redistribution was dependent on an active nuclear export system. These results strongly suggest that Mcb1 promotes efficient pre-RC formation during DNA replication by regulating the MCM complex.

  10. The Fission Yeast Minichromosome Maintenance (MCM)-binding Protein (MCM-BP), Mcb1, Regulates MCM Function during Prereplicative Complex Formation in DNA Replication*

    Science.gov (United States)

    Santosa, Venny; Martha, Sabrina; Hirose, Noriaki; Tanaka, Katsunori

    2013-01-01

    The minichromosome maintenance (MCM) complex is a replicative helicase, which is essential for chromosome DNA replication. In recent years, the identification of a novel MCM-binding protein (MCM-BP) in most eukaryotes has led to numerous studies investigating its function and its relationship to the MCM complex. However, the mechanisms by which MCM-BP functions and associates with MCM complexes are not well understood; in addition, the functional role of MCM-BP remains controversial and may vary between model organisms. The present study aims to elucidate the nature and biological function of the MCM-BP ortholog, Mcb1, in fission yeast. The Mcb1 protein continuously interacts with MCM proteins during the cell cycle in vivo and can interact with any individual MCM subunit in vitro. To understand the detailed characteristics of mcb1+, two temperature-sensitive mcb1 gene mutants (mcb1ts) were isolated. Extensive genetic analysis showed that the mcb1ts mutants were suppressed by a mcm5+ multicopy plasmid and displayed synthetic defects with many S-phase-related gene mutants. Moreover, cyclin-dependent kinase modulation by Cig2 repression or Rum1 overproduction suppressed the mcb1ts mutants, suggesting the involvement of Mcb1 in pre-RC formation during DNA replication. These data are consistent with the observation that Mcm7 loading onto replication origins is reduced and S-phase progression is delayed in mcb1ts mutants. Furthermore, the mcb1ts mutation led to the redistribution of MCM subunits to the cytoplasm, and this redistribution was dependent on an active nuclear export system. These results strongly suggest that Mcb1 promotes efficient pre-RC formation during DNA replication by regulating the MCM complex. PMID:23322785

  11. Polyethylenimine-modified curcumin-loaded mesoporus silica nanoparticle (MCM-41) induces cell death in MCF-7 cell line.

    Science.gov (United States)

    Harini, Lakshminarasimhan; Karthikeyan, Bose; Srivastava, Sweta; Suresh, Srinag Bangalore; Ross, Cecil; Gnanakumar, Georgepeter; Rajagopal, Srinivasan; Sundar, Krishnan; Kathiresan, Thandavarayan

    2017-02-01

    Breast cancer accounts for the first highest mortality rate in India and second in world. Though current treatment strategies are effectively killing cancer cells, they also end in causing severe side effects and drug resistance. Curcumin is a nutraceutical with multipotent activity but its insolubility in water limits its therapeutic potential as an anti-cancer drug. The hydrophilicity of curcumin could be increased by nanoformulation or changing its functional groups. In this study, curcumin is loaded on mesoporous silica nanoparticle and its anti-cancer activity is elucidated with MCF-7 cell death. Structural characteristics of Mobil Composition of Matter - 41(MCM-41) as determined by high-resolution transmission electron microscopy (HR-TEM) shows that MCM-41 size ranges from 100 to 200 nm diameters with pore size 2-10 nm for drug adsorption. The authors found 80-90% of curcumin is loaded on MCM-41 and curcumin is released efficiently at pH 3.0. The 50 µM curcumin-loaded MCM-41 induced 50% mortality of MCF-7 cells. Altogether, their results suggested that increased curcumin loading and sustained release from MCM-41 effectively decreased cell survival of MCF-7 cells in vitro.

  12. Two subunits of human ORC are dispensable for DNA replication and proliferation.

    Science.gov (United States)

    Shibata, Etsuko; Kiran, Manjari; Shibata, Yoshiyuki; Singh, Samarendra; Kiran, Shashi; Dutta, Anindya

    2016-12-01

    The six-subunit Origin Recognition Complex (ORC) is believed to be an essential eukaryotic ATPase that binds to origins of replication as a ring-shaped heterohexamer to load MCM2-7 and initiate DNA replication. We have discovered that human cell lines in culture proliferate with intact chromosomal origins of replication after disruption of both alleles of ORC2 or of the ATPase subunit, ORC1 . The ORC1 or ORC2 -depleted cells replicate with decreased chromatin loading of MCM2-7 and become critically dependent on another ATPase, CDC6, for survival and DNA replication. Thus, either the ORC ring lacking a subunit, even its ATPase subunit, can load enough MCM2-7 in partnership with CDC6 to initiate DNA replication, or cells have an ORC-independent, CDC6-dependent mechanism to load MCM2-7 on origins of replication.

  13. Prognostic significance of MCM 2 and Ki-67 in neuroblastic tumors in children.

    Science.gov (United States)

    Lewandowska, Magdalena; Taran, Katarzyna; Sitkiewicz, Anna; Andrzejewska, Ewa

    2015-12-02

    Neuroblastic tumors can be characterized by three features: spontaneous regression, maturation and aggressive proliferation. The most common and routinely used method of assessing tumor cell proliferation is to determine the Ki-67 index in the tumor tissue. Despite numerous studies, neuroblastoma biology is not fully understood, which makes treatment results unsatisfactory. MCM 2 is a potential prognostic factor in the neuroblastoma group. The study is based on retrospective analysis of 35 patients treated for neuroblastic tumors in the Department of Pediatric Surgery and Oncology of the Medical University of Lodz, during the period 2001-2011. The material comprised tissues of 16 tumors excised during the operation and 19 biopsy specimens. Immunohistochemical examinations were performed with immunoperoxidase using mouse monoclonal anti-MCM 2 and anti-Ki-67 antibodies. We observed that MCM 2 expression ranged from 2% to 98% and the Ki-67 index ranged from 0 to 95%. There was a statistically significant correlation between expression of MCM 2 and the value of the Ki-67 index and a correlation close to statistical significance between expression of MCM 2 and unfavorable histopathology. There was no statistical relationship between expression of MCM 2 and age over 1 year and N-myc amplification. The presented research shows that MCM 2 may have prognostic significance in neuroblastic pediatric tumors and as a potential prognostic factor could be the starting point of new individualized therapy.

  14. Cross flow ultrafiltration of Cr (VI) using MCM-41, MCM-48 and Faujasite (FAU) zeolite-ceramic composite membranes.

    Science.gov (United States)

    Basumatary, Ashim Kumar; Kumar, R Vinoth; Ghoshal, Aloke Kumar; Pugazhenthi, G

    2016-06-01

    This work describes the removal of Cr (VI) from aqueous solution in cross flow mode using MCM-41, MCM-48 and FAU zeolite membranes prepared on circular shaped porous ceramic support. Ceramic support was manufactured using locally available clay materials via a facile uni-axial compaction method followed by sintering process. A hydrothermal technique was employed for the deposition of zeolites on the ceramic support. The porosity of ceramic support (47%) is reduced by the formation of MCM-41 (23%), MCM-48 (22%) and FAU (33%) zeolite layers. The pore size of the MCM-41, MCM-48 and FAU membrane is found to be 0.173, 0.142, and 0.153 μm, respectively, which is lower than that of the support (1.0 μm). Cross flow ultrafiltration experiments of Cr (VI) were conducted at five different applied pressures (69-345 kPa) and three cross flow rates (1.11 × 10(-7) - 2.22 × 10(-7) m(3)/s). The filtration studies inferred that the performance of the fabricated zeolite composite membranes is optimum at the maximum applied pressure (345 kPa) and the highest rejection is obtained with the lowest cross flow rate (1.11 × 10(-7) m(3)/s) for all three zeolite membrane. The permeate flux of MCM-41, MCM-48 and FAU zeolite composite membranes are almost remained constant in the entire duration of the separation process. The highest removal of 82% is shown by FAU membrane, while MCM-41 and MCM-48 display 75% and 77% of Cr (VI) removal, respectively for the initial feed concentration of 1000 ppm with natural pH of the solution at an applied pressure of 345 kPa. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Structural changes in Mcm5 protein bypass Cdc7-Dbf4 function and reduce replication origin efficiency in Saccharomyces cerevisiae.

    Science.gov (United States)

    Hoang, Margaret L; Leon, Ronald P; Pessoa-Brandao, Luis; Hunt, Sonia; Raghuraman, M K; Fangman, Walton L; Brewer, Bonita J; Sclafani, Robert A

    2007-11-01

    Eukaryotic chromosomal replication is a complicated process with many origins firing at different efficiencies and times during S phase. Prereplication complexes are assembled on all origins in G(1) phase, and yet only a subset of complexes is activated during S phase by DDK (for Dbf4-dependent kinase) (Cdc7-Dbf4). The yeast mcm5-bob1 (P83L) mutation bypasses DDK but results in reduced intrinsic firing efficiency at 11 endogenous origins and at origins located on minichromosomes. Origin efficiency may result from Mcm5 protein assuming an altered conformation, as predicted from the atomic structure of an archaeal MCM (for minichromosome maintenance) homologue. Similarly, an intragenic mutation in a residue predicted to interact with P83L suppresses the mcm5-bob1 bypass phenotype. We propose DDK phosphorylation of the MCM complex normally results in a single, highly active conformation of Mcm5, whereas the mcm5-bob1 mutation produces a number of conformations, only one of which is permissive for origin activation. Random adoption of these alternate states by the mcm5-bob1 protein can explain both how origin firing occurs independently of DDK and why origin efficiency is reduced. Because similar mutations in mcm2 and mcm4 cannot bypass DDK, Mcm5 protein may be a unique Mcm protein that is the final target of DDK regulation.

  16. Mcm10 regulates DNA replication elongation by stimulating the CMG replicative helicase.

    Science.gov (United States)

    Lõoke, Marko; Maloney, Michael F; Bell, Stephen P

    2017-02-01

    Activation of the Mcm2-7 replicative DNA helicase is the committed step in eukaryotic DNA replication initiation. Although Mcm2-7 activation requires binding of the helicase-activating proteins Cdc45 and GINS (forming the CMG complex), an additional protein, Mcm10, drives initial origin DNA unwinding by an unknown mechanism. We show that Mcm10 binds a conserved motif located between the oligonucleotide/oligosaccharide fold (OB-fold) and A subdomain of Mcm2. Although buried in the interface between these domains in Mcm2-7 structures, mutations predicted to separate the domains and expose this motif restore growth to conditional-lethal MCM10 mutant cells. We found that, in addition to stimulating initial DNA unwinding, Mcm10 stabilizes Cdc45 and GINS association with Mcm2-7 and stimulates replication elongation in vivo and in vitro. Furthermore, we identified a lethal allele of MCM10 that stimulates initial DNA unwinding but is defective in replication elongation and CMG binding. Our findings expand the roles of Mcm10 during DNA replication and suggest a new model for Mcm10 function as an activator of the CMG complex throughout DNA replication. © 2017 Lõoke et al.; Published by Cold Spring Harbor Laboratory Press.

  17. Cdt1p, through its interaction with Mcm6p, is required for the formation, nuclear accumulation and chromatin loading of the MCM complex.

    Science.gov (United States)

    Wu, Rentian; Wang, Jiafeng; Liang, Chun

    2012-01-01

    Regulation of DNA replication initiation is essential for the faithful inheritance of genetic information. Replication initiation is a multi-step process involving many factors including ORC, Cdt1p, Mcm2-7p and other proteins that bind to replication origins to form a pre-replicative complex (pre-RC). As a prerequisite for pre-RC assembly, Cdt1p and the Mcm2-7p heterohexameric complex accumulate in the nucleus in G1 phase in an interdependent manner in budding yeast. However, the nature of this interdependence is not clear, nor is it known whether Cdt1p is required for the assembly of the MCM complex. In this study, we provide the first evidence that Cdt1p, through its interaction with Mcm6p with the C-terminal regions of the two proteins, is crucial for the formation of the MCM complex in both the cytoplasm and nucleoplasm. We demonstrate that disruption of the interaction between Cdt1p and Mcm6p prevents the formation of the MCM complex, excludes Mcm2-7p from the nucleus, and inhibits pre-RC assembly and DNA replication. Our findings suggest a function for Cdt1p in promoting the assembly of the MCM complex and maintaining its integrity by interacting with Mcm6p.

  18. The MCM-associated protein MCM-BP is important for human nuclear morphology.

    Science.gov (United States)

    Jagannathan, Madhav; Sakwe, Amos M; Nguyen, Tin; Frappier, Lori

    2012-01-01

    Mini-chromosome maintenance complex-binding protein (MCM-BP) was discovered as a protein that is strongly associated with human MCM proteins, known to be crucial for DNA replication in providing DNA helicase activity. The Xenopus MCM-BP homologue appears to play a role in unloading MCM complexes from chromatin after DNA synthesis; however, the importance of MCM-BP and its functional contribution to human cells has been unclear. Here we show that depletion of MCM-BP by sustained expression of short hairpin RNA (shRNA) results in highly abnormal nuclear morphology and centrosome amplification. The abnormal nuclear morphology was not seen with depletion of other MCM proteins and was rescued with shRNA-resistant MCM-BP. MCM-BP depletion was also found to result in transient activation of the G2 checkpoint, slowed progression through G2 and increased replication protein A foci, indicative of replication stress. In addition, MCM-BP depletion led to increased cellular levels of MCM proteins throughout the cell cycle including soluble MCM pools. The results suggest that MCM-BP makes multiple contributions to human cells that are not limited to unloading of the MCM complex.

  19. Automated seismic waveform location using Multichannel Coherency Migration (MCM)-I. Theory

    Science.gov (United States)

    Shi, Peidong; Angus, Doug; Rost, Sebastian; Nowacki, Andy; Yuan, Sanyi

    2018-03-01

    With the proliferation of dense seismic networks sampling the full seismic wavefield, recorded seismic data volumes are getting bigger and automated analysis tools to locate seismic events are essential. Here, we propose a novel Multichannel Coherency Migration (MCM) method to locate earthquakes in continuous seismic data and reveal the location and origin time of seismic events directly from recorded waveforms. By continuously calculating the coherency between waveforms from different receiver pairs, MCM greatly expands the available information which can be used for event location. MCM does not require phase picking or phase identification, which allows fully automated waveform analysis. By migrating the coherency between waveforms, MCM leads to improved source energy focusing. We have tested and compared MCM to other migration-based methods in noise-free and noisy synthetic data. The tests and analysis show that MCM is noise resistant and can achieve more accurate results compared with other migration-based methods. MCM is able to suppress strong interference from other seismic sources occurring at a similar time and location. It can be used with arbitrary 3D velocity models and is able to obtain reasonable location results with smooth but inaccurate velocity models. MCM exhibits excellent location performance and can be easily parallelized giving it large potential to be developed as a real-time location method for very large datasets.

  20. MCM interference during licensing of DNA replication in Xenopus egg extracts-Possible Role of a C-terminal region of MCM3.

    Science.gov (United States)

    Mimura, Satoru; Kubota, Yumiko; Takisawa, Haruhiko

    2018-01-01

    The minichromosome maintenance (MCM) complex, consisting of six subunits, Mcm2-7, is loaded onto replication origins through loading factors (origin recognition complex [ORC], Cdc6, and Cdt1) and forms an MCM double hexamer that licenses the initiation of DNA replication. Previous studies with Xenopus egg extracts showed that loading factors, especially Cdc6, dissociate from chromatin on MCM loading, but the molecular mechanism and physiological significance remain largely unknown. Using a cell-free system for MCM loading onto plasmid DNA in Xenopus egg extracts, we found that MCM loaded onto DNA prevents DNA binding of the loading factors ORC, Cdc6, and Cdt1. We further report that a peptide of the C-terminal region of MCM3 (MCM3-C), previously implicated in the initial association with ORC/Cdc6 in budding yeast, prevents ORC/Cdc6/Cdt1 binding to DNA in the absence of MCM loading. ATP-γ-S suppresses inhibitory activities of both the MCM loaded onto DNA and the MCM3-C peptide. Other soluble factors in the extract, but neither MCM nor Cdt1, are required for the activity. Conservation of the amino acid sequences of MCM3-C and its activity in vertebrates implies a novel negative autoregulatory mechanism that interferes with MCM loading in the vicinity of licensed origins to ensure proper origin licensing.

  1. Comparison of the value of PCNA and Ki-67 as markers of cell proliferation in ameloblastic tumor

    Science.gov (United States)

    Mosqueda-Taylor, Adalberto; Molina-Frechero, Nelly; Mori-Estevez, Ana D.; Sánchez-Acuña, Guillermo

    2013-01-01

    Objectives: The aim of this study was to compare among PCNAand Ki-67 as the most reliable immunohistochemical marker for evaluating cell proliferation in ameloblastic tumors. Study Design: Observational, retrospective, and descriptive study of a large series of ameloblastic tumors, composed of 161 ameloblastomas and four ameloblastic carcinomas, to determine and compare PCNA and Ki-67 expression using immunohistochemistry techniques. Results: When analyzing Ki-67 positivity, the desmoplastic ameloblastoma demonstrated a significantly lower proliferation rate (1.9%) compared with the solid/multicystic and unicystic ameloblastomas and ameloblastic carcinomas (p<0.05), whereas the ameloblastic carcinomas displayed a significantly higher rate compared with all of the other ameloblastomas (48.7%) (p<0.05). When analyzing cell proliferation with PCNA, we found significant differences only between the ameloblastic carcinomas (93.3%) and the desmoplastic ameloblastomas (p<0.05). When differences between the immunopositivity for PCNA and Ki-67 were compared, the percentages were higher for PCNA in all types of ameloblastomas and ameloblastic carcinomas. In all cases, the percentages were greater than 80%, whereas the immunopositivity for Ki-67 was significantly lower; for example, the ameloblastic carcinoma expressed the highest positivity and only reached 48.7%, compared to 93.3% when we used PCNA. Conclusions: In the present study, when we used the proliferation cell marker Ki-67, the percentages of positivity were more specific and varied among the different types of ameloblastomas, suggesting that Ki-67 is a more specific marker for the proliferation of ameloblastic tumor cells. Key words:Ameloblastomas, ameloblastic carcinoma, PCNA, Ki-67, cell proliferation markers. PMID:23229269

  2. A conserved MCM single-stranded DNA binding element is essential for replication initiation.

    Science.gov (United States)

    Froelich, Clifford A; Kang, Sukhyun; Epling, Leslie B; Bell, Stephen P; Enemark, Eric J

    2014-04-01

    The ring-shaped MCM helicase is essential to all phases of DNA replication. The complex loads at replication origins as an inactive double-hexamer encircling duplex DNA. Helicase activation converts this species to two active single hexamers that encircle single-stranded DNA (ssDNA). The molecular details of MCM DNA interactions during these events are unknown. We determined the crystal structure of the Pyrococcus furiosus MCM N-terminal domain hexamer bound to ssDNA and define a conserved MCM-ssDNA binding motif (MSSB). Intriguingly, ssDNA binds the MCM ring interior perpendicular to the central channel with defined polarity. In eukaryotes, the MSSB is conserved in several Mcm2-7 subunits, and MSSB mutant combinations in S. cerevisiae Mcm2-7 are not viable. Mutant Mcm2-7 complexes assemble and are recruited to replication origins, but are defective in helicase loading and activation. Our findings identify an important MCM-ssDNA interaction and suggest it functions during helicase activation to select the strand for translocation. DOI: http://dx.doi.org/10.7554/eLife.01993.001.

  3. An Mcm10 Mutant Defective in ssDNA Binding Shows Defects in DNA Replication Initiation.

    Science.gov (United States)

    Perez-Arnaiz, Patricia; Kaplan, Daniel L

    2016-11-20

    Mcm10 is an essential protein that functions to initiate DNA replication after the formation of the replication fork helicase. In this manuscript, we identified a budding yeast Mcm10 mutant (Mcm10-m2,3,4) that is defective in DNA binding in vitro. Moreover, this Mcm10-m2,3,4 mutant does not stimulate the phosphorylation of Mcm2 by Dbf4-dependent kinase (DDK) in vitro. When we expressed wild-type levels of mcm10-m2,3,4 in budding yeast cells, we observed a severe growth defect and a substantially decreased DNA replication. We also observed a substantially reduced replication protein A- chromatin immunoprecipitation signal at origins of replication, reduced levels of DDK-phosphorylated Mcm2, and diminished Go, Ichi, Ni, and San (GINS) association with Mcm2-7 in vivo. mcm5-bob1 bypasses the growth defect conferred by DDK-phosphodead Mcm2 in budding yeast. However, the growth defect observed by expressing mcm10-m2,3,4 is not bypassed by the mcm5-bob1 mutation. Furthermore, origin melting and GINS association with Mcm2-7 are substantially decreased for cells expressing mcm10-m2,3,4 in the mcm5-bob1 background. Thus, the origin melting and GINS-Mcm2-7 interaction defects we observed for mcm10-m2,3,4 are not explained by decreased Mcm2 phosphorylation by DDK, since the defects persist in an mcm5-bob1 background. These data suggest that DNA binding by Mcm10 is essential for the initiation of DNA replication. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Recruitment of Mcm10 to Sites of Replication Initiation Requires Direct Binding to the Minichromosome Maintenance (MCM) Complex*

    Science.gov (United States)

    Douglas, Max E.

    2016-01-01

    Mcm10 is required for the initiation of eukaryotic DNA replication and contributes in some unknown way to the activation of the Cdc45-MCM-GINS (CMG) helicase. How Mcm10 is localized to sites of replication initiation is unclear, as current models indicate that direct binding to minichromosome maintenance (MCM) plays a role, but the details and functional importance of this interaction have not been determined. Here, we show that purified Mcm10 can bind both DNA-bound double hexamers and soluble single hexamers of MCM. The binding of Mcm10 to MCM requires the Mcm10 C terminus. Moreover, the binding site for Mcm10 on MCM includes the Mcm2 and Mcm6 subunits and overlaps that for the loading factor Cdt1. Whether Mcm10 recruitment to replication origins depends on CMG helicase assembly has been unclear. We show that Mcm10 recruitment occurs via two modes: low affinity recruitment in the absence of CMG assembly (“G1-like”) and high affinity recruitment when CMG assembly takes place (“S-phase-like”). Mcm10 that cannot bind directly to MCM is defective in both modes of recruitment and is unable to support DNA replication. These findings indicate that Mcm10 is localized to replication initiation sites by directly binding MCM through the Mcm10 C terminus. PMID:26719337

  5. Recruitment of Mcm10 to Sites of Replication Initiation Requires Direct Binding to the Minichromosome Maintenance (MCM) Complex.

    Science.gov (United States)

    Douglas, Max E; Diffley, John F X

    2016-03-11

    Mcm10 is required for the initiation of eukaryotic DNA replication and contributes in some unknown way to the activation of the Cdc45-MCM-GINS (CMG) helicase. How Mcm10 is localized to sites of replication initiation is unclear, as current models indicate that direct binding to minichromosome maintenance (MCM) plays a role, but the details and functional importance of this interaction have not been determined. Here, we show that purified Mcm10 can bind both DNA-bound double hexamers and soluble single hexamers of MCM. The binding of Mcm10 to MCM requires the Mcm10 C terminus. Moreover, the binding site for Mcm10 on MCM includes the Mcm2 and Mcm6 subunits and overlaps that for the loading factor Cdt1. Whether Mcm10 recruitment to replication origins depends on CMG helicase assembly has been unclear. We show that Mcm10 recruitment occurs via two modes: low affinity recruitment in the absence of CMG assembly ("G1-like") and high affinity recruitment when CMG assembly takes place ("S-phase-like"). Mcm10 that cannot bind directly to MCM is defective in both modes of recruitment and is unable to support DNA replication. These findings indicate that Mcm10 is localized to replication initiation sites by directly binding MCM through the Mcm10 C terminus. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  6. Cold thyroid nodules show a marked increase in proliferation markers.

    Science.gov (United States)

    Krohn, Knut; Stricker, Ingo; Emmrich, Peter; Paschke, Ralf

    2003-06-01

    Thyroid follicular adenomas and adenomatous thyroid nodules are a frequent finding in geographical areas with iodine deficiency. They occur as hypofunctioning (scintigraphically cold) or hyperfunctioning (scintigraphically hot) nodules. Their predominant clonal origin suggests that they result from clonal expansion of a single cell, which is very likely the result of a prolonged increase in proliferation compared with non-affected surrounding cells. To test whether increased cell proliferation is detectable in cold thyroid nodules, we studied paraffin-embedded tissue from 40 cold thyroid nodules and their surrounding normal thyroid tissue for the occurrence of the proliferating cell nuclear antigen (PCNA) and Ki-67 (MIB-1 antibody) epitopes as markers for cell proliferation. All 40 thyroid nodules were histologically well characterized and have been studied for molecular characteristics before. The labeling index (number of labeled cells versus total cell number) for nodular and surrounding tissue was calculated. In 33 cold thyroid nodules a significant (p thyroid nodules a significant (p thyroid epithelial cell proliferation is a uniform feature common to most cold nodules. However, the increase of proliferation markers shows a heterogeneity that is not correlated with histopathologic, molecular, or clinical characteristics.

  7. The PS1 hairpin of Mcm3 is essential for viability and for DNA unwinding in vitro.

    Directory of Open Access Journals (Sweden)

    Simon K W Lam

    Full Text Available The pre-sensor 1 (PS1 hairpin is found in ring-shaped helicases of the AAA+ family (ATPases associated with a variety of cellular activities of proteins and is implicated in DNA translocation during DNA unwinding of archaeal mini-chromosome maintenance (MCM and superfamily 3 viral replicative helicases. To determine whether the PS1 hairpin is required for the function of the eukaryotic replicative helicase, Mcm2-7 (also comprised of AAA+ proteins, we mutated the conserved lysine residue in the putative PS1 hairpin motif in each of the Saccharomyces cerevisiae Mcm2-7 subunits to alanine. Interestingly, only the PS1 hairpin of Mcm3 was essential for viability. While mutation of the PS1 hairpin in the remaining MCM subunits resulted in minimal phenotypes, with the exception of Mcm7 which showed slow growth under all conditions examined, the viable alleles were synthetic lethal with each other. Reconstituted Mcm2-7 containing Mcm3 with the PS1 mutation (Mcm3(K499A had severely decreased helicase activity. The lack of helicase activity provides a probable explanation for the inviability of the mcm3(K499A strain. The ATPase activity of Mcm2-7(3K499A was similar to the wild type complex, but its interaction with single-stranded DNA in an electrophoretic mobility shift assay and its associations in cells were subtly altered. Together, these findings indicate that the PS1 hairpins in the Mcm2-7 subunits have important and distinct functions, most evident by the essential nature of the Mcm3 PS1 hairpin in DNA unwinding.

  8. MCM Paradox: Abundance of Eukaryotic Replicative Helicases and Genomic Integrity.

    Science.gov (United States)

    Das, Mitali; Singh, Sunita; Pradhan, Satyajit; Narayan, Gopeshwar

    2014-01-01

    As a crucial component of DNA replication licensing system, minichromosome maintenance (MCM) 2-7 complex acts as the eukaryotic DNA replicative helicase. The six related MCM proteins form a heterohexamer and bind with ORC, CDC6, and Cdt1 to form the prereplication complex. Although the MCMs are well known as replicative helicases, their overabundance and distribution patterns on chromatin present a paradox called the "MCM paradox." Several approaches had been taken to solve the MCM paradox and describe the purpose of excess MCMs distributed beyond the replication origins. Alternative functions of these MCMs rather than a helicase had also been proposed. This review focuses on several models and concepts generated to solve the MCM paradox coinciding with their helicase function and provides insight into the concept that excess MCMs are meant for licensing dormant origins as a backup during replication stress. Finally, we extend our view towards the effect of alteration of MCM level. Though an excess MCM constituent is needed for normal cells to withstand stress, there must be a delineation of the threshold level in normal and malignant cells. This review also outlooks the future prospects to better understand the MCM biology.

  9. Cerium incorporated MCM-48 (Ce-MCM-48) as a catalyst to inhibit bromate formation during ozonation of bromide-containing water: Efficacy and mechanism.

    Science.gov (United States)

    Li, Weiwei; Lu, Xiaowei; Xu, Ke; Qu, Jiuhui; Qiang, Zhimin

    2015-12-01

    The composite mesoporous sieve Ce-MCM-48 (cerium incorporated MCM-48) with different Si/Ce molar ratios were synthesized hydrothermally and characterized with X-ray diffraction, X-ray photoelectron spectroscopy, BET surface area, and pHpzc. Results indicate that Ce-MCM-48, especially with a Si/Ce molar ratio of 66 (i.e., Ce66-MCM-48), could significantly inhibit bromate (BrO3(-)) formation during ozonation of Br(-)-containing water, achieving 91% of inhibition efficiency at pH 7.6 and 25 °C. An acidic or alkaline pH decreased the inhibition efficiency of Ce66-MCM-48 to some extent, but reaction temperature ranging from 15 to 30 °C had no significant impact. By comparing the bromine mass balance, aqueous O3 decomposition, and newly formed H2O2 between O3 and O3/Ce66-MCM-48 processes, the inhibition mechanism was proposed: Ce66-MCM-48 promoted aqueous O3 decomposition to generate hydroxyl radicals (OH) that could merge into H2O2, so the oxidative transformation of Br(-) and HOBr/OBr(-) by O3 and OH was primarily suppressed. The catalytic ability of Ce66-MCM-48 was continuously regenerated through the circulating reactions between Ce(III) and Ce(IV) occurring on the catalyst surface. Besides its inhibition on BrO3(-) formation, Ce66-MCM-48 could also enhance the degradation of refractory organic micropollutants. Because of these distinct merits, Ce66-MCM-48 has potential applications to water treatment by ozone. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Highly stable loading of Mcm proteins onto chromatin in living cells requires replication to unload

    Science.gov (United States)

    Kuipers, Marjorie A.; Stasevich, Timothy J.; Sasaki, Takayo; Wilson, Korey A.; Hazelwood, Kristin L.; McNally, James G.; Davidson, Michael W.

    2011-01-01

    The heterohexameric minichromosome maintenance protein complex (Mcm2-7) functions as the eukaryotic helicase during DNA replication. Mcm2-7 loads onto chromatin during early G1 phase but is not converted into an active helicase until much later during S phase. Hence, inactive Mcm complexes are presumed to remain stably bound from early G1 through the completion of S phase. Here, we investigated Mcm protein dynamics in live mammalian cells. We demonstrate that Mcm proteins are irreversibly loaded onto chromatin cumulatively throughout G1 phase, showing no detectable exchange with a gradually diminishing soluble pool. Eviction of Mcm requires replication; during replication arrest, Mcm proteins remained bound indefinitely. Moreover, the density of immobile Mcms is reduced together with chromatin decondensation within sites of active replication, which provides an explanation for the lack of colocalization of Mcm with replication fork proteins. These results provide in vivo evidence for an exceptionally stable lockdown mechanism to retain all loaded Mcm proteins on chromatin throughout prolonged cell cycles. PMID:21220507

  11. Rif1 controls DNA replication by directing Protein Phosphatase 1 to reverse Cdc7-mediated phosphorylation of the MCM complex.

    Science.gov (United States)

    Hiraga, Shin-Ichiro; Alvino, Gina M; Chang, Fujung; Lian, Hui-Yong; Sridhar, Akila; Kubota, Takashi; Brewer, Bonita J; Weinreich, Michael; Raghuraman, M K; Donaldson, Anne D

    2014-02-15

    Initiation of eukaryotic DNA replication requires phosphorylation of the MCM complex by Dbf4-dependent kinase (DDK), composed of Cdc7 kinase and its activator, Dbf4. We report here that budding yeast Rif1 (Rap1-interacting factor 1) controls DNA replication genome-wide and describe how Rif1 opposes DDK function by directing Protein Phosphatase 1 (PP1)-mediated dephosphorylation of the MCM complex. Deleting RIF1 partially compensates for the limited DDK activity in a cdc7-1 mutant strain by allowing increased, premature phosphorylation of Mcm4. PP1 interaction motifs within the Rif1 N-terminal domain are critical for its repressive effect on replication. We confirm that Rif1 interacts with PP1 and that PP1 prevents premature Mcm4 phosphorylation. Remarkably, our results suggest that replication repression by Rif1 is itself also DDK-regulated through phosphorylation near the PP1-interacting motifs. Based on our findings, we propose that Rif1 is a novel PP1 substrate targeting subunit that counteracts DDK-mediated phosphorylation during replication. Fission yeast and mammalian Rif1 proteins have also been implicated in regulating DNA replication. Since PP1 interaction sites are evolutionarily conserved within the Rif1 sequence, it is likely that replication control by Rif1 through PP1 is a conserved mechanism.

  12. Expression of lysophosphatidic acid receptor 1 and relation with cell proliferation, apoptosis, and angiogenesis on preneoplastic changes induced by cadmium chloride in the rat ventral prostate.

    Directory of Open Access Journals (Sweden)

    Riánsares Arriazu

    Full Text Available BACKGROUND: Lysophosphatidic acid (LPA is a phospholipid growth factor involved in cell proliferation, differentiation, migration, inflammation, angiogenesis, wound healing, cancer invasion, and survival. This study was directed to evaluate the immunoexpression of LPA-1, cell proliferation, apoptosis, and angiogenesis markers in preneoplastic lesions induced with cadmium chloride in rat prostate. METHODS: The following parameters were calculated in ventral prostate of normal rats and rats that received Cd in drinking water during 24 months: percentages of cells immunoreactive to LPA-1 (LILPA1, PCNA (LIPCNA, MCM7 (LIMCM7, ubiquitin (LIUBI, apoptotic cells (LIAPO, and p53 (LIp53; volume fraction of Bcl-2 (VFBcl-2; and length of microvessels per unit of volume (LVMV/mm3. Data were analyzed using Student's t-test and Pearson correlation test. RESULTS: The LILPA1 in dysplastic lesions and normal epithelium of Cd-treated rats was significantly higher than those in the control group. Markers of proliferation were significantly increased in dysplastic lesions, whereas some apoptotic markers were significantly decreased. No significant differences between groups were found in VFBcl-2. Dysplastic lesions showed a significant increase of LIp53. The length of microvessels per unit of volume was elevated in dysplastic acini. Statistically significant correlations were found only between LILPA1 and LIUBI. CONCLUSIONS: Our results suggest that LPA-1 might be implicated in dysplastic lesions induced by cadmium chloride development. More studies are needed to confirm its potential contribution to the disease.

  13. Adsorption of CO2 on amine-functionalised MCM-41: experimental and theoretical studies.

    Science.gov (United States)

    dos Santos, Thiago Custódio; Bourrelly, Sandrine; Llewellyn, Philip L; Carneiro, José Walkimar de M; Ronconi, Célia Machado

    2015-04-28

    Adsorption of CO2 on MCM-41 functionalised with [3-(2-aminoethylamino)propyl]trimethoxysilane (MCM-41-N2), N(1)-(3-trimethoxysilylpropyl)diethylenetriamine (MCM-41-N3), 4-aminopyridine (MCM-41-aminopyridine), 4-(methylamino)pyridine (MCM-41-methylaminopyridine) and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (MCM-41-guanidine) was investigated. The amine-functionalised materials were characterised by (29)Si and (13)C solid-state nuclear magnetic resonance, N2 adsorption/desorption isotherms, X-ray diffraction and transmission electron microscopy. CO2 adsorption at 1.0 bar and 30 °C showed that the amount of CO2 (nads/mmol g(-1)) adsorbed on MCM-41-N2 and MCM-41-N3 is approximately twice the amount adsorbed on MCM-41. For MCM-41-aminopyridine, MCM-41-methylaminopyridine and MCM-41-guanidine, the CO2 adsorption capacity was smaller than that of MCM-41 at the same conditions. The proton affinity (computed with wB97x-D/6-311++G(d,p)) of the secondary amino groups is higher than that of the primary amino groups; however, the relative stabilities of the primary and secondary carbamates are similar. The differential heat of adsorption decreases as the number of secondary amino groups increases.

  14. Synthesis, Characterization and Application of the novel, regular mesoporous materials MCM-41 and MCM-48

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, R

    1995-07-01

    In the application of zeolites to catalytic cracking of heavy oil fractions the need of regular solids with large pore sizes has become very obvious. The scope of this thesis was to synthesize and characterize the novel mesoporous materials MCM-41 and MCM-48 with the major emphasis laid on MCM-41. MCM-41 materials with bulk Si/Al ratios of 4, 9, 18 and {infinity} were synthesized and characterized by XRD and HREM. The catalytic cracking behaviour of Al-containing MCM-41 materials was investigated by pulse reactor studies using decalin as model feed and by Micro Activity Tests using atmospheric residue or n-hexadecane as feed. Aluminium containing MCM-41 was found to be active for the cracking of heavy oil fractions. Purely siliceous MCM-41 materials with pore sizes ranging from 18 Aa to 40 Aa were synthesized and their properties studied by means of NMR spectroscopy. The MCM-48, which is a cubic member of the M41S family with a three dimensional pore system, was studied by means of a combination of X-ray powder diffraction and HREM technique. 210 refs., 76 figs., 9 tabs.

  15. Flexible DNA Path in the MCM Double Hexamer Loaded on DNA.

    Science.gov (United States)

    Hizume, Kohji; Kominami, Hiroaki; Kobayashi, Kei; Yamada, Hirofumi; Araki, Hiroyuki

    2017-05-16

    The formation of the pre-replicative complex (pre-RC) during the G1 phase, which is also called the licensing of DNA replication, is the initial and essential step of faithful DNA replication during the subsequent S phase. It is widely accepted that in the pre-RC, double-stranded DNA passes through the holes of two ring-shaped minichromosome maintenance (MCM) 2-7 hexamers; however, the spatial organization of the DNA and proteins involved in pre-RC formation is unclear. Here we reconstituted the pre-RC from purified DNA and proteins and visualized the complex using atomic force microscopy (AFM). AFM revealed that the MCM double hexamers formed elliptical particles on DNA. Analysis of the angle of binding of DNA to the MCM double hexamer suggests that the DNA does not completely pass through both holes of the MCM hexamers, possibly because the DNA exited from the gap between Mcm2 and Mcm5. A DNA loop fastened by the MCM double hexamer was detected in pre-RC samples reconstituted from purified proteins as well as those purified from yeast cells, suggesting a higher-order architecture of the loaded MCM hexamers and DNA strands.

  16. Amino-functionalized MCM-41 and MCM-48 for the removal of chromate and arsenate.

    Science.gov (United States)

    Benhamou, A; Basly, J P; Baudu, M; Derriche, Z; Hamacha, R

    2013-08-15

    The aim of the present work was to investigate the efficiency of three amino-functionalized (hexadecylamine, dodecylamine, and dimethyldodecylamine) mesoporous silicas (MCM-41 and MCM-48) toward the adsorption of arsenate and chromate. Hexadecylamine-functionalized materials were characterized; BET surface areas, pore volumes, and sizes decreased with the functionalization, whereas XRD patterns show that the hexagonal structure of MCM-41 and the cubic structure of MCM-48 were not modified. The zeta potential decreases with pH and the highest arsenate and chromate removal was observed at the lowest pHs. Adsorption of chromium and arsenate was significantly enhanced after functionalization and amino-functionalized MCM-41 adsorb larger amounts of arsenate when compared to expanded MCM-48 materials. Chromate sorption capacities increased with the chain length and the larger capacities were obtained with hexadecylamine-functionalized mesoporous silicas. Mesoporous silicas modified by dimethyldodecylamine exhibited the higher arsenate sorption capacities. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. A radial glia gene marker, fatty acid binding protein 7 (FABP7, is involved in proliferation and invasion of glioblastoma cells.

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    Antonella De Rosa

    Full Text Available Glioblastoma multiforme (GBM is among the most deadly cancers. A number of studies suggest that a fraction of tumor cells with stem cell features (Glioma Stem-like Cells, GSC might be responsible for GBM recurrence and aggressiveness. GSC similarly to normal neural stem cells, can form neurospheres (NS in vitro, and seem to mirror the genetic features of the original tumor better than glioma cells growing adherently in the presence of serum. Using cDNA microarray analysis we identified a number of relevant genes for glioma biology that are differentially expressed in adherent cells and neurospheres derived from the same tumor. Fatty acid-binding protein 7 (FABP7 was identified as one of the most highly expressed genes in NS compared to their adherent counterpart. We found that down-regulation of FABP7 expression in NS by small interfering RNAs significantly reduced cell proliferation and migration. We also evaluated the potential involvement of FABP7 in response to radiotherapy, as this treatment may cause increased tumor infiltration. Migration of irradiated NS was associated to increased expression of FABP7. In agreement with this, in vivo reduced tumorigenicity of GBM cells with down-regulated expression of FABP7 was associated to decreased expression of the migration marker doublecortin. Notably, we observed that PPAR antagonists affect FABP7 expression and decrease the migration capability of NS after irradiation. As a whole, the data emphasize the role of FABP7 expression in GBM migration and provide translational hints on the timing of treatment with anti-FABP7 agents like PPAR antagonists during GBM evolution.

  18. Gel-like properties of MCM-41 material and its transformation to MCM-50 in a caustic alkaline surround

    International Nuclear Information System (INIS)

    Saputra, Hens; Othman, Raihan; Sutjipto, A.G.E.; Muhida, R.; Ani, M.H.

    2012-01-01

    Highlights: ► MCM-41 material transforms gradually into MCM-50 lamellar gel upon controlled exposure to 6 M KOH. ► The formation of MCM-50 ordered gel structure occurs at KOH weight content of 40–70 wt. %. ► MCM gel phase shows pseudoplastic behavior and possesses homogeneous matrix texture. -- Abstract: MCM-41 material, prepared by sol–gel method, reveals gel-like properties in a caustic alkaline environment, i.e., 6 M potassium hydroxide (KOH) electrolyte. The gellation of MCM-41 starts at a KOH weight ratio of 40 wt.%. The structural change of the material is verified with X-Ray diffractograms and supported by observation using Scanning Electron Microscope (SEM). As the KOH weight ratio increases, the MCM-41 hexagonal arrays structure gradually transforms into MCM-50 lamellar structure before disappearing completely at 80 wt.% KOH. The MCM gel phase is further characterized by rotational viscometry and texture analysis. The gel phase shows shear thinning or pseudoplastic behavior and possesses homogeneous matrix structure.

  19. The Mini-Chromosome Maintenance (Mcm) Complexes Interact with DNA Polymerase α-Primase and Stimulate Its Ability to Synthesize RNA Primers

    Science.gov (United States)

    You, Zhiying; De Falco, Mariarosaria; Kamada, Katsuhiko; Pisani, Francesca M.; Masai, Hisao

    2013-01-01

    The Mini-chromosome maintenance (Mcm) proteins are essential as central components for the DNA unwinding machinery during eukaryotic DNA replication. DNA primase activity is required at the DNA replication fork to synthesize short RNA primers for DNA chain elongation on the lagging strand. Although direct physical and functional interactions between helicase and primase have been known in many prokaryotic and viral systems, potential interactions between helicase and primase have not been explored in eukaryotes. Using purified Mcm and DNA primase complexes, a direct physical interaction is detected in pull-down assays between the Mcm2∼7 complex and the hetero-dimeric DNA primase composed of the p48 and p58 subunits. The Mcm4/6/7 complex co-sediments with the primase and the DNA polymerase α-primase complex in glycerol gradient centrifugation and forms a Mcm4/6/7-primase-DNA ternary complex in gel-shift assays. Both the Mcm4/6/7 and Mcm2∼7 complexes stimulate RNA primer synthesis by DNA primase in vitro. However, primase inhibits the Mcm4/6/7 helicase activity and this inhibition is abolished by the addition of competitor DNA. In contrast, the ATP hydrolysis activity of Mcm4/6/7 complex is not affected by primase. Mcm and primase proteins mutually stimulate their DNA-binding activities. Our findings indicate that a direct physical interaction between primase and Mcm proteins may facilitate priming reaction by the former protein, suggesting that efficient DNA synthesis through helicase-primase interactions may be conserved in eukaryotic chromosomes. PMID:23977294

  20. The mini-chromosome maintenance (Mcm complexes interact with DNA polymerase α-primase and stimulate its ability to synthesize RNA primers.

    Directory of Open Access Journals (Sweden)

    Zhiying You

    Full Text Available The Mini-chromosome maintenance (Mcm proteins are essential as central components for the DNA unwinding machinery during eukaryotic DNA replication. DNA primase activity is required at the DNA replication fork to synthesize short RNA primers for DNA chain elongation on the lagging strand. Although direct physical and functional interactions between helicase and primase have been known in many prokaryotic and viral systems, potential interactions between helicase and primase have not been explored in eukaryotes. Using purified Mcm and DNA primase complexes, a direct physical interaction is detected in pull-down assays between the Mcm2~7 complex and the hetero-dimeric DNA primase composed of the p48 and p58 subunits. The Mcm4/6/7 complex co-sediments with the primase and the DNA polymerase α-primase complex in glycerol gradient centrifugation and forms a Mcm4/6/7-primase-DNA ternary complex in gel-shift assays. Both the Mcm4/6/7 and Mcm2~7 complexes stimulate RNA primer synthesis by DNA primase in vitro. However, primase inhibits the Mcm4/6/7 helicase activity and this inhibition is abolished by the addition of competitor DNA. In contrast, the ATP hydrolysis activity of Mcm4/6/7 complex is not affected by primase. Mcm and primase proteins mutually stimulate their DNA-binding activities. Our findings indicate that a direct physical interaction between primase and Mcm proteins may facilitate priming reaction by the former protein, suggesting that efficient DNA synthesis through helicase-primase interactions may be conserved in eukaryotic chromosomes.

  1. The haloarchaeal MCM proteins: bioinformatic analysis and targeted mutagenesis of the β7-β8 and β9-β10 hairpin loops and conserved zinc binding domain cysteines.

    Science.gov (United States)

    Kristensen, Tatjana P; Maria Cherian, Reeja; Gray, Fiona C; MacNeill, Stuart A

    2014-01-01

    The hexameric MCM complex is the catalytic core of the replicative helicase in eukaryotic and archaeal cells. Here we describe the first in vivo analysis of archaeal MCM protein structure and function relationships using the genetically tractable haloarchaeon Haloferax volcanii as a model system. Hfx. volcanii encodes a single MCM protein that is part of the previously identified core group of haloarchaeal MCM proteins. Three structural features of the N-terminal domain of the Hfx. volcanii MCM protein were targeted for mutagenesis: the β7-β8 and β9-β10 β-hairpin loops and putative zinc binding domain. Five strains carrying single point mutations in the β7-β8 β-hairpin loop were constructed, none of which displayed impaired cell growth under normal conditions or when treated with the DNA damaging agent mitomycin C. However, short sequence deletions within the β7-β8 β-hairpin were not tolerated and neither was replacement of the highly conserved residue glutamate 187 with alanine. Six strains carrying paired alanine substitutions within the β9-β10 β-hairpin loop were constructed, leading to the conclusion that no individual amino acid within that hairpin loop is absolutely required for MCM function, although one of the mutant strains displays greatly enhanced sensitivity to mitomycin C. Deletions of two or four amino acids from the β9-β10 β-hairpin were tolerated but mutants carrying larger deletions were inviable. Similarly, it was not possible to construct mutants in which any of the conserved zinc binding cysteines was replaced with alanine, underlining the likely importance of zinc binding for MCM function. The results of these studies demonstrate the feasibility of using Hfx. volcanii as a model system for reverse genetic analysis of archaeal MCM protein function and provide important confirmation of the in vivo importance of conserved structural features identified by previous bioinformatic, biochemical and structural studies.

  2. The haloarchaeal MCM proteins: bioinformatic analysis and targeted mutagenesis of the β7-β8 and β9-β10 hairpin loops and conserved zinc binding domain cysteines

    Directory of Open Access Journals (Sweden)

    Tatjana P Kristensen

    2014-03-01

    Full Text Available The hexameric MCM complex is the catalytic core of the replicative helicase in eukaryotic and archaeal cells. Here we describe the first in vivo analysis of archaeal MCM protein structure and function relationships using the genetically tractable haloarchaeon Haloferax volcanii as a model system. Hfx. volcanii encodes a single MCM protein that is part of the previously identified core group of haloarchaeal MCM proteins. Three structural features of the N-terminal domain of the Hfx. volcanii MCM protein were targeted for mutagenesis: the β7-β8 and β9-β10 β-hairpin loops and putative zinc binding domain. Five strains carrying single point mutations in the β7-β8 β-hairpin loop were constructed, none of which displayed impaired cell growth under normal conditions or when treated with the DNA damaging agent mitomycin C. However, short sequence deletions within the β7-β8 β-hairpin were not tolerated and neither was replacement of the highly conserved residue glutamate 187 with alanine. Six strains carrying paired alanine substitutions within the β9-β10 β-hairpin loop were constructed, leading to the conclusion that no individual amino acid within that hairpin loop is absolutely required for MCM function, although one of the mutant strains displays greatly enhanced sensitivity to mitomycin C. Deletions of two or four amino acids from the β9-β10 β-hairpin were tolerated but mutants carrying larger deletions were inviable. Similarly, it was not possible to construct mutants in which any of the conserved zinc binding cysteines was replaced with alanine, underlining the likely importance of zinc binding for MCM function. The results of these studies demonstrate the feasibility of using Hfx. volcanii as a model system for reverse genetic analysis of archaeal MCM protein function and provide important confirmation of the in vivo importance of conserved structural features identified by previous bioinformatic, biochemical and structural

  3. A new MCM modification cycle regulates DNA replication initiation.

    Science.gov (United States)

    Wei, Lei; Zhao, Xiaolan

    2016-03-01

    The MCM DNA helicase is a central regulatory target during genome replication. MCM is kept inactive during G1, and it initiates replication after being activated in S phase. During this transition, the only known chemical change to MCM is the gain of multisite phosphorylation that promotes cofactor recruitment. Because replication initiation is intimately linked to multiple biological cues, additional changes to MCM can provide further regulatory points. Here, we describe a yeast MCM SUMOylation cycle that regulates replication. MCM subunits undergo SUMOylation upon loading at origins in G1 before MCM phosphorylation. MCM SUMOylation levels then decline as MCM phosphorylation levels rise, thus suggesting an inhibitory role of MCM SUMOylation during replication. Indeed, increasing MCM SUMOylation impairs replication initiation, partly through promoting the recruitment of a phosphatase that decreases MCM phosphorylation and activation. We propose that MCM SUMOylation counterbalances kinase-based regulation, thus ensuring accurate control of replication initiation.

  4. Multiple domains of fission yeast Cdc19p (MCM2) are required for its association with the core MCM complex.

    Science.gov (United States)

    Sherman, D A; Pasion, S G; Forsburg, S L

    1998-07-01

    The members of the MCM protein family are essential eukaryotic DNA replication factors that form a six-member protein complex. In this study, we use antibodies to four MCM proteins to investigate the structure of and requirements for the formation of fission yeast MCM complexes in vivo, with particular regard to Cdc19p (MCM2). Gel filtration analysis shows that the MCM protein complexes are unstable and can be broken down to subcomplexes. Using coimmunoprecipitation, we find that Mis5p (MCM6) and Cdc21p (MCM4) are tightly associated with one another in a core complex with which Cdc19p loosely associates. Assembly of Cdc19p with the core depends upon Cdc21p. Interestingly, there is no obvious change in Cdc19p-containing MCM complexes through the cell cycle. Using a panel of Cdc19p mutants, we find that multiple domains of Cdc19p are required for MCM binding. These studies indicate that MCM complexes in fission yeast have distinct substructures, which may be relevant for function.

  5. Metal-Chelate Immobilization of Lipase onto Polyethylenimine Coated MCM-41 for Apple Flavor Synthesis.

    Science.gov (United States)

    Sadighi, Armin; Motevalizadeh, Seyed Farshad; Hosseini, Morteza; Ramazani, Ali; Gorgannezhad, Lena; Nadri, Hamid; Deiham, Behnaz; Ganjali, Mohammad Reza; Shafiee, Abbas; Faramarzi, Mohammad Ali; Khoobi, Mehdi

    2017-08-01

    An enzyme immobilized on a mesoporous silica nanoparticle can serve as a multiple catalyst for the synthesis of industrially useful chemicals. In this work, MCM-41 nanoparticles were coated with polyethylenimine (MCM-41@PEI) and further modified by chelation of divalent metal ions (M = Co 2+ , Cu 2+ , or Pd 2+ ) to produce metal-chelated silica nanoparticles (MCM-41@PEI-M). Thermomyces lanuginosa lipase (TLL) was immobilized onto MCM-41, MCM-41@PEI, and MCM-41@PEI-M by physical adsorption. Maximum immobilization yield and efficiency of 75 ± 3.5 and 65 ± 2.7% were obtained for MCM@PEI-Co, respectively. The highest biocatalytic activity at extremely acidic and basic pH (pH = 3 and 10) values were achieved for MCM-PEI-Co and MCM-PEI-Cu, respectively. Optimum enzymatic activity was observed for MCM-41@PEI-Co at 75 °C, while immobilized lipase on the Co-chelated support retained 70% of its initial activity after 14 days of storage at room temperature. Due to its efficient catalytic performance, MCM-41@PEI-Co was selected for the synthesis of ethyl valerate in the presence of valeric acid and ethanol. The enzymatic esterification yield for immobilized lipase onto MCM-41@PEI-Co was 60 and 53%, respectively, after 24 h of incubation in n-hexane and dimethyl sulfoxide media. Graphical Abstract Divalent metal chelated polyethylenimine coated MCM-41 (MCM-41@PEI-M) was used for immobilization of Thermomyces lanuginosa lipase catalyzing green apple flavor preparation.

  6. The investigation of MCM-48-type and MCM-41-type mesoporous silica as oral solid dispersion carriers for water insoluble cilostazol.

    Science.gov (United States)

    Wang, Yanzhu; Sun, Lizhang; Jiang, Tongying; Zhang, Jinghai; Zhang, Chen; Sun, Changshan; Deng, Yihui; Sun, Jin; Wang, Siling

    2014-06-01

    To explore the suitable application of MCM-41 (Mobil Composition of Matter number forty-one)-type and MCM-48-type mesoporous silica in the oral water insoluble drug delivery system. Cilostazol (CLT) as a model drug was loaded into synthesized MCM-48 (Mobil Composition of Matter number forty-eight) and commercial MCM-41 by three common methods. The obtained MCM-41, MCM-48 and CLT-loaded samples were characterized by means of nitrogen adsorption, thermogravimetric analysis, ultraviolet-visible spectrophotometry, scanning electron microscopy, transmission electron microscopy, differential scanning calorimetry and powder X-ray diffractometer. It was found that solvent evaporation method was preferred according to the drug loading efficiency and the maximum percent cumulative drug dissolution. MCM-48 with 3D cubic pore structure and MCM-41 with 2D long tubular structure are nearly spherical particles in 300-500 nm. Nevertheless, the silica carriers with similar large specific surface areas and concentrating pore size distributions (978.66 m(2)/g, 3.8 nm for MCM-41 and 1108.04 m(2)/g, 3.6 nm for MCM-48) exhibited different adsorption behaviors for CLT. The maximum percent cumulative drug release of the two CLT/silica solid dispersion (CLT-MCM-48 and CLT-MCM-41) was 63.41% and 85.78% within 60 min, respectively; while in the subsequent 12 h release experiment, almost 100% cumulative drug release were both obtained. In the pharmacokinetics aspect, the maximum plasma concentrations of CLT-MCM-48 reached 3.63 mg/L by 0.92 h. The AUC0-∞ values of the CLT-MCM-41 and CLT-MCM-48 were 1.14-fold and 1.73-fold, respectively, compared with the commercial preparation. Our findings suggest that MCM-41-type and MCM-48-type mesoporous silica have great promise as solid dispersion carriers for sustained and immediate release separately.

  7. Cytometry of chromatin bound Mcm6 and PCNA identifies two states in G1 that are separated functionally by the G1 restriction point1

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    Jacobberger James W

    2010-04-01

    Full Text Available Abstract Background Cytometric measurements of DNA content and chromatin-bound Mcm2 have demonstrated bimodal patterns of expression in G1. These patterns, the replication licensing function of Mcm proteins, and a correlation between Mcm loading and cell cycle commitment for cells re-entering the cell cycle, led us to test the idea that cells expressing a defined high level of chromatin-bound Mcm6 in G1 are committed - i.e., past the G1 restriction point. We developed a cell-based assay for tightly-bound PCNA (PCNA* and Mcm6 (Mcm6*, DNA content, and a mitotic marker to clearly define G1, S, G2, and M phases of the cell cycle. hTERT-BJ1, hTERT-RPE-1, and Molt4 cells were extracted with Triton X-100 followed by methanol fixation, stained with antibodies and DAPI, then measured by cytometry. Results Bivariate analysis of cytometric data demonstrated complex patterns with distinct clustering for all combinations of the 4 variables. In G1, cells clustered in two groups characterized by low and high Mcm6* expression. Serum starvation and release experiments showed that residence in the high group was in late G1, just prior to S phase. Kinetic experiments, employing serum withdrawal, and stathmokinetic analysis with aphidicolin, mimosine or nocodazole demonstrated that cells with high levels of Mcm6* cycled with the committed phases of the cell cycle (S, G2, and M. Conclusions A multivariate assay for Mcm6*, PCNA*, DNA content, and a mitotic marker provides analysis capable of estimating the fraction of pre and post-restriction point G1 cells and supports the idea that there are at least two states in G1 defined by levels of chromatin bound Mcm proteins.

  8. Hidrólise de celulose por catalisadores mesoestruturados NiO-MCM-41 e MoO3-MCM-41

    Directory of Open Access Journals (Sweden)

    Adriano Sant'Ana Silva

    2012-01-01

    Full Text Available This study was carried out to synthesize, characterize and evaluate the application of mesoestruturated catalysts MCM-41, 5%MoO3-MCM-41 and 5%NiO-MCM-41 in the hydrolysis of microcrystalline cellulose. XRD results indicate that the phase of mesoporous MCM-41 was obtained and that the introduction of metal oxides did not affect this mesoporous phase. About the heterogeneous hydrolysis reaction, it was observed that the increase in temperature results in a higher concentration of glucose and the catalyst 5%MoO3-MCM-41 provides the highest concentrations of glucose.

  9. Minichromosome Maintenance Expression Defines Slow-Growing Gastroenteropancreatic Neuroendocrine Neoplasms

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    Simon Schimmack

    2016-10-01

    Full Text Available BACKGROUND: Small intestinal neuroendocrine neoplasm (SI-NEN proliferation is quantified by Ki67 measurements which capture G1-G2M phases of the cell cycle. G0 and early G1 phases, typical of slow-growing cells, can be detected by minichromosome maintenance protein (MCM expression. We hypothesized that these replication licensing markers may provide clinically relevant information to augment Ki67 in low-grade neuroendocrine neoplasia. METHODS: Immunohistochemical staining (IHC, Western blot analysis, quantitative polymerase chain reaction, and copy number variations of MCM2, MCM3, and Ki67 were undertaken in SI-NENs (n = 22. MCM and Ki67 expression was compared by Kaplan-Meier survival analysis (tissue microarray, independent set [n = 55]. Forty-three pancreatic NENs and 14 normal tissues were included as controls. RESULTS: In SI-NENs, MCM2 (mean: 21.2%: range: 16%-25% and MCM3 (28.7%: 22%-34% were detected in significantly more cells than Ki67 (2.3%: 0%-7%, P < .01. MCM2 mRNA correlated with Ki67 IHC (P < .05. MCM3 protein expression was higher in metastases (38-fold than in normal small intestine (P = .06 and was largely absent in normal neuroendocrine cells. There was considerable variation at the MCM copy number level (0-4 copies. MCM3 expression in proliferating cells significantly predicted overall survival (P < .002. Combinations of Ki67 and MCM2/3 in algorithms differentiated low and higher proliferative lesions (overall survival: 12 vs 6.1 years, P = .06. MCM expression was not informative in pancreatic NENs. CONCLUSION: MCMs are expressed in a higher proportion of NEN cells than Ki67 in slow-growing small intestinal lesions and correlate with survival. Assessment can be used to augment Ki67 to improve prognostic classification in these low-grade tumors.

  10. How MCM loading and spreading specify eukaryotic DNA replication initiation sites.

    Science.gov (United States)

    Hyrien, Olivier

    2016-01-01

    DNA replication origins strikingly differ between eukaryotic species and cell types. Origins are localized and can be highly efficient in budding yeast, are randomly located in early fly and frog embryos, which do not transcribe their genomes, and are clustered in broad (10-100 kb) non-transcribed zones, frequently abutting transcribed genes, in mammalian cells. Nonetheless, in all cases, origins are established during the G1-phase of the cell cycle by the loading of double hexamers of the Mcm 2-7 proteins (MCM DHs), the core of the replicative helicase. MCM DH activation in S-phase leads to origin unwinding, polymerase recruitment, and initiation of bidirectional DNA synthesis. Although MCM DHs are initially loaded at sites defined by the binding of the origin recognition complex (ORC), they ultimately bind chromatin in much greater numbers than ORC and only a fraction are activated in any one S-phase. Data suggest that the multiplicity and functional redundancy of MCM DHs provide robustness to the replication process and affect replication time and that MCM DHs can slide along the DNA and spread over large distances around the ORC. Recent studies further show that MCM DHs are displaced along the DNA by collision with transcription complexes but remain functional for initiation after displacement. Therefore, eukaryotic DNA replication relies on intrinsically mobile and flexible origins, a strategy fundamentally different from bacteria but conserved from yeast to human. These properties of MCM DHs likely contribute to the establishment of broad, intergenic replication initiation zones in higher eukaryotes.

  11. FBXW7/hCDC4 controls glioma cell proliferation in vitro and is a prognostic marker for survival in glioblastoma patients

    Directory of Open Access Journals (Sweden)

    Hagedorn Martin

    2007-02-01

    Full Text Available Abstract Background In the quest for novel molecular mediators of glioma progression, we studied the regulation of FBXW7 (hCDC4/hAGO/SEL10, its association with survival of patients with glioblastoma and its potential role as a tumor suppressor gene in glioma cells. The F-box protein Fbxw7 is a component of SCFFbxw7, a Skp1-Cul1-F-box E3 ubiquitin ligase complex that tags specific proteins for proteasome degradation. FBXW7 is mutated in several human cancers and functions as a haploinsufficient tumor suppressor in mice. Any of the identified targets, Cyclin E, c-Myc, c-Jun, Notch1/4 and Aurora-A may have oncogenic properties when accumulated in tumors with FBXW7 loss. Results We tested the expression of FBXW7 in human glioma biopsies by quantitative PCR and compared the transcript levels of grade IV glioma (glioblastoma, G-IV with those of grade II tumors (G-II. In more than 80% G-IV, expression of FBXW7 was significantly reduced. In addition, levels of FBXW7 were correlated with survival indicating a possible implication in tumor aggressiveness. Locus 4q31.3 which carries FBXW7 was investigated by in situ hybridization on biopsy touchprints. This excluded allelic loss as the principal cause for low expression of FBXW7 in G-IV tumors. Two targets of Fbxw7, Aurora-A and Notch4 were preferentially immunodetected in G-IV biopsies. Next, we investigated the effects of FBXW7 misregulation in glioma cells. U87 cells overexpressing nuclear isoforms of Fbxw7 lose the expression of the proliferation markers PCNA and Ki-67, and get counterselected in vitro. This observation fits well with the hypothesis that Fbxw7 functions as a tumor suppressor in astroglial cells. Finally, FBXW7 knockdown in U87 cells leads to defects in mitosis that may promote aneuploidy in progressing glioma. Conclusion Our results show that FBXW7 expression is a prognostic marker for patients with glioblastoma. We suggest that loss of FBXW7 plays an important role in glioma

  12. Ordered cubic nanoporous silica support MCM-48 for delivery of poorly soluble drug indomethacin

    Science.gov (United States)

    Zeleňák, Vladimír; Halamová, Dáša; Almáši, Miroslav; Žid, Lukáš; Zeleňáková, Adriána; Kapusta, Ondrej

    2018-06-01

    Ordered MCM-48 nanoporous silica (SBET = 923(3) m2·g-1, VP = 0.63(2) cm3·g-1) with cubic Ia3d symmetry was used as a support for drug delivery of anti-inflammatory poorly soluble drug indomethacin. The delivery from parent, unmodified MCM-48, and 3-aminopropyl modified silica carrier was studied into the simulated body fluids with the pH = 2 and pH = 7.4. The studied samples were characterized by thermal analysis (TG/DTG-DTA), N2 adsorption/desorption, infrared spectroscopy (FT-IR), powder XRD, SEM, HRTEM methods, measurements of zeta potential (ζ) and dynamic light scattering (DLS). The determined content of indomethacin in pure MCM-48 was 21 wt.% and in the amine-modified silica MCM-48A-I the content was 45 wt.%. The release profile of the drug, in the time period up to 72 h, was monitored by TLC chromatographic method. It as shown, that by the modification of the surface, the drug release can be controlled. The slower release of indomethacin was observed from amino modified sample MCM-48A-I in the both types of studied simulated body fluids (slightly alkaline intravenous solution with pH = 7.4 and acidic gastric fluid with pH = 2), which was supported and explained by zeta potential and DLS measurements. The amount of the released indomethacin into the fluids with various pH was different. The maximum released amount of the drug was 97% for sample containing unmodified silica, MCM-48-I at pH = 7.4 and lowest released amount, 57%, for amine modified sample MCM-48A-I at pH = 2. To compare the indomethacin release profile four kinetic models were tested. Results showed, that that the drug release based on diffusion Higuchi model, mainly governs the release.

  13. Transformation of levoglucosan over H-MCM-22 zeolite and H-MCM-41 mesoporous molecular sieve catalysts

    International Nuclear Information System (INIS)

    Kaeldstroem, M.; Kumar, N.; Heikkilae, T.; Tiitta, M.; Salmi, T.; Murzin, D. Yu.

    2011-01-01

    Catalytic transformation of levoglucosan (1-6-anhdyro-β-D-glucopyranose) was carried out in a fixed bed reactor at 573 K over zeolite and mesoporous material catalysts. Proton forms of MCM-22-30 and MCM-41-20 catalysts were tested in the conversion, changing also the residence time. The yield of the transformation product phases was substantially influenced by the structures, at the same time the formation of the different compounds were dependent on the structures of the acidic zeolite catalysts. Oxygenated species were the main liquid product, consisting mainly of aldehydes and furfurals (glycolaldehyde, formaldehyde, acetaldehyde, furfural, 5-methylfurfural, acetic acid). The formation of the liquid products was higher over MCM-41-20 than over MCM-22-30 for all the oxygenated species except acetic acid, indicating larger formation of non-condensable products over the microporous material. By increasing the residence time the formation of acetic acid increased in transformations over MCM-22, however, such increase also led to generation of more gases with both catalysts. The deactivation due to coking was more severe over the zeolite compared to the mesoporous material. It was, however, possible to successfully regenerate the spent zeolites without changing the structure. -- Highlights: → Transformation of levoglucosan (1-6-anhdyro-β-D-glucopyranose) was done at 573 K. → MCM-22-30 and MCM-41-20 catalysts were tested. → Oxygenated species (glycolaldehyde, formaldehyde, acetaldehyde, furfural, 5-methylfurfural, acetic acid) were the main liquid products. → Acidity had an influence on product distribution and deactivation.

  14. Tetracycline-Containing MCM-41 Mesoporous Silica Nanoparticles for the Treatment of Escherichia coli.

    Science.gov (United States)

    Koneru, Bhuvaneswari; Shi, Yi; Wang, Yu-Chieh; Chavala, Sai H; Miller, Michael L; Holbert, Brittany; Conson, Maricar; Ni, Aiguo; Di Pasqua, Anthony J

    2015-10-30

    Tetracycline (TC) is a well-known broad spectrum antibiotic, which is effective against many Gram positive and Gram negative bacteria. Controlled release nanoparticle formulations of TC have been reported, and could be beneficial for application in the treatment of periodontitis and dental bone infections. Furthermore, TC-controlled transcriptional regulation systems (Tet-on and Tet-off) are useful for controlling transgene expression in vitro and in vivo for biomedical research purposes; controlled TC release systems could be useful here, as well. Mesoporous silica nanomaterials (MSNs) are widely studied for drug delivery applications; Mobile crystalline material 41 (MCM-41), a type of MSN, has a mesoporous structure with pores forming channels in a hexagonal fashion. We prepared 41 ± 4 and 406 ± 55 nm MCM-41 mesoporous silica nanoparticles and loaded TC for controlled dug release; TC content in the TC-MCM-41 nanoparticles was 18.7% and 17.7% w/w, respectively. Release of TC from TC-MCM-41 nanoparticles was then measured in phosphate-buffered saline (PBS), pH 7.2, at 37 °C over a period of 5 h. Most antibiotic was released from both over this observation period; however, the majority of TC was released over the first hour. Efficacy of the TC-MCM-41 nanoparticles was then shown to be superior to free TC against Escherichia coli (E. coli) in culture over a 24 h period, while blank nanoparticles had no effect.

  15. Cdt1 stabilizes an open MCM ring for helicase loading.

    Science.gov (United States)

    Frigola, Jordi; He, Jun; Kinkelin, Kerstin; Pye, Valerie E; Renault, Ludovic; Douglas, Max E; Remus, Dirk; Cherepanov, Peter; Costa, Alessandro; Diffley, John F X

    2017-06-23

    ORC, Cdc6 and Cdt1 act together to load hexameric MCM, the motor of the eukaryotic replicative helicase, into double hexamers at replication origins. Here we show that Cdt1 interacts with MCM subunits Mcm2, 4 and 6, which both destabilizes the Mcm2-5 interface and inhibits MCM ATPase activity. Using X-ray crystallography, we show that Cdt1 contains two winged-helix domains in the C-terminal half of the protein and a catalytically inactive dioxygenase-related N-terminal domain, which is important for MCM loading, but not for subsequent replication. We used these structures together with single-particle electron microscopy to generate three-dimensional models of MCM complexes. These show that Cdt1 stabilizes MCM in a left-handed spiral open at the Mcm2-5 gate. We propose that Cdt1 acts as a brace, holding MCM open for DNA entry and bound to ATP until ORC-Cdc6 triggers ATP hydrolysis by MCM, promoting both Cdt1 ejection and MCM ring closure.

  16. Fabrication of MCM-41 fibers with well-ordered hexagonal mesostructure controlled in acidic and alkaline media

    International Nuclear Information System (INIS)

    Jafarzadeh, A.; Sohrabnezhad, Sh.; Zanjanchi, M.A.; Arvand, M.

    2016-01-01

    In this paper, synthesis and characterization of two type morphologies of the MCM-41mesoporous material, nano and microfibers, were investigated by electrospinning technique. The synthesis was performed in acidic and alkaline media, separately. The MCM-41 morphologies were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray powder diffraction (XRD), and nitrogen adsorption–desorption measurement. Tetraethylorthosilicate (TEOS) and cetyltrimethylammonium bromide (CTAB) were used as silica and template sources for the synthesis of MCM-41 morphologies, respectively. The SEM results showed that MCM-41 nanofibers were spun in acidic media and microfibers of MCM-41 were produced in alkaline media. The XRD study revealed a long range structural ordering of mesoporous materials. The TEM results indicated rough surfaces with uniform average diameter 200 nm for nanofibers and 2 µm for microfibers. The pore diameter and surface area of calcined MCM-41 nanofibers were 2.2 nm and 970 m 2 /g, respectively. For the MCM-41 microfibers, pore sizes of 2.7 nm and surface areas 420 m 2 /g was measured. - Graphical abstract: Electrospinning method was used for fabricating of MCM-41 microfibers from TEOS in alkaline media (top) and MCM-41 nanofibers in acidic media (bottom). - Highlights: • Synthesis of MCM-41 nanofibers and microfibers by electrospinning technique. • MCM-41 nanofibers were synthesized in acidic media. • MCM-41 manofibers spun in alkaline media. • Electrospinning was a simple method for preparing of fibers with respect to chemical method.

  17. Optical properties of (nanometer MCM-41)-(malachite green) composite materials

    International Nuclear Information System (INIS)

    Li Xiaodong; Zhai Qingzhou; Zou Mingqiang

    2010-01-01

    Nanosized materials loaded with organic dyes are of interest with respect to novel optical applications. The optical properties of malachite green (MG) in MCM-41 are considerably influenced by the limited nanoporous channels of nanometer MCM-41. Nanometer MCM-41 was synthesized by tetraethyl orthosilicate (TEOS) as the source of silica and cetyltrimethylammonium bromide (CTMAB) as the template. The liquid-phase grafting method has been employed for incorporation of the malachite green molecules into the channels of nanometer MCM-41. A comparative study has been carried out on the adsorption of the malachite green into modified MCM-41 and unmodified MCM-41. The modified MCM-41 was synthesized using a silylation reagent, trimethychlorosilane (TMSCl), which functionalized the surface of nanometer MCM-41 for proper host-guest interaction. The prepared (nanometer MCM-41)-MG samples have been studied by powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, low-temperature nitrogen adsorption-desorption technique at 77 K, Raman spectra and luminescence studies. In the prepared (nanometer MCM-41)-MG composite materials, the frameworks of the host molecular sieve were kept intact and the MG located inside the pores of MCM-41. Compared with the MG, it is found that the prepared composite materials perform a considerable luminescence. The excitation and emission spectra of MG in both modified MCM-41 and unmodified MCM-41 were examined to explore the structural effects on the optical properties of MG. The results of luminescence spectra indicated that the MG molecules existed in monomer form within MCM-41. However, the luminescent intensity of MG incorporated in the modified MCM-41 are higher than that of MG encapsulated in unmodified MCM-41, which may be due to the anchored methyl groups on the channels of the nanometer MCM-41 and the strong host-guest interactions. The steric effect from the pore size of the host materials is significant. Raman

  18. Archaeal orthologs of Cdc45 and GINS form a stable complex that stimulates the helicase activity of MCM.

    Science.gov (United States)

    Xu, Yuli; Gristwood, Tamzin; Hodgson, Ben; Trinidad, Jonathan C; Albers, Sonja-Verena; Bell, Stephen D

    2016-11-22

    The regulated recruitment of Cdc45 and GINS is key to activating the eukaryotic MCM(2-7) replicative helicase. We demonstrate that the homohexameric archaeal MCM helicase associates with orthologs of GINS and Cdc45 in vivo and in vitro. Association of these factors with MCM robustly stimulates the MCM helicase activity. In contrast to the situation in eukaryotes, archaeal Cdc45 and GINS form an extremely stable complex before binding MCM. Further, the archaeal GINS•Cdc45 complex contains two copies of Cdc45. Our analyses give insight into the function and evolution of the conserved core of the archaeal/eukaryotic replisome.

  19. The Helicase Activity of Hyperthermophilic Archaeal MCM is Enhanced at High Temperatures by Lysine Methylation.

    Science.gov (United States)

    Xia, Yisui; Niu, Yanling; Cui, Jiamin; Fu, Yang; Chen, Xiaojiang S; Lou, Huiqiang; Cao, Qinhong

    2015-01-01

    Lysine methylation and methyltransferases are widespread in the third domain of life, archaea. Nevertheless, the effects of methylation on archaeal proteins wait to be defined. Here, we report that recombinant sisMCM, an archaeal homolog of Mcm2-7 eukaryotic replicative helicase, is methylated by aKMT4 in vitro. Mono-methylation of these lysine residues occurs coincidently in the endogenous sisMCM protein purified from the hyperthermophilic Sulfolobus islandicus cells as indicated by mass spectra. The helicase activity of mini-chromosome maintenance (MCM) is stimulated by methylation, particularly at temperatures over 70°C. The methylated MCM shows optimal DNA unwinding activity after heat-treatment between 76 and 82°C, which correlates well with the typical growth temperatures of hyperthermophilic Sulfolobus. After methylation, the half life of MCM helicase is dramatically extended at 80°C. The methylated sites are located on the accessible protein surface, which might modulate the intra- and inter- molecular interactions through changing the hydrophobicity and surface charge. Furthermore, the methylation-mimic mutants of MCM show heat resistance helicase activity comparable to the methylated MCM. These data provide the biochemical evidence that posttranslational modifications such as methylation may enhance kinetic stability of proteins under the elevated growth temperatures of hyperthermophilic archaea.

  20. Study on thermal, mechanical and adsorption properties of amine-functionalized MCM-41/PMMA and MCM-41/PS nanocomposites prepared by ultrasonic irradiation.

    Science.gov (United States)

    Mohammadnezhad, Gholamhossein; Abad, Saeed; Soltani, Roozbeh; Dinari, Mohammad

    2017-11-01

    In this study, two common industrial polymers, poly(methyl methacrylate) (PMMA) and polystyrene (PS), were incorporated into amine-functionalized MCM-41 mesoporous silica as reinforcement agents via an ultrasonic assisted method as a facile, fast, eco-friendly, and versatile synthetic tool. Amino functionalization of MCM-41 were performed by 3-aminopropyl triethoxysilane as a coupling agent and it is denoted as APTS-MCM-41. The obtained nanocomposites (NCs), APTS-MCM-41/PMMA and APTS-MCM-41/PS, were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning and transmission electron microscopies (SEM and TEM), and thermogravimetric analysis (TGA). Their mechanical properties were also probed via stress-strain curves and improved tensile properties were observed in the NCs relative to the neat polymers. Additionally, APTS-MCM-41/PMMA exhibited better mechanical properties than APTS-MCM-41/PS. Sorption studies were carried out on the two NCs and the effect of different process parameters, namely, pH, contact time, and initial Cd(II) concentration investigated in batch mode. Pseudo-second order and intraparticle diffusion models explain the Cd(II) kinetics more effectively for APTS-MCM-41/PMMA and APTS-MCM-41/PS, respectively. The adsorption isotherm data fitted well to Langmuir isotherm for both NCs and the maximum monolayer adsorption capacities were found to be 24.75mg/g and 10.42mg/g for APTS-MCM-41/PMMA and APTS-MCM-41/PS, respectively. The results demonstrate that the NCs show potential for use in adsorption of heavy metal ion such as Cd(II) from aqueous media. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Structure, luminescence, and dynamics of Eu2O3 nanoparticles in MCM-41

    International Nuclear Information System (INIS)

    Chen, Wei; Joly, Alan G.; Kowalchuk, George A.; Malm, Jan-Olle; Huang, Yining; Bovin, Jan-Olov

    2001-01-01

    The structure, luminescence spectroscopy, and lifetime decay dynamics of Eu2O3 nanoparticles formed in MCM-41 have been investigated. Both X-ray diffraction and high resolution transmission electron microscope observations indicate that Eu2O3 nanoparticles of monoclinic structure are formed inside channels of MCM-41 by heating at 140 C. However, heat treatment at 600 and 700 C causes migration of Eu2O3 from the MCM-41 channels forming nanoparticles of cubic structure outside of the MCM-41 channels. The feature of the hypersensitive 5D0? 7F2 emission profile of Eu3+ is used to follow the structural changes. Photoluminescence lifetimes show the existence of short (< 1 microsecond) and long (microsecond to millisecond) components for each sample. The fast decay is attributed to quenching by surface states of the nanoparticles or energy transfer to the MCM-41 while the longer time decays show the effects of concentration quenching. The monoclinic sample prepared at 140 C shows a higher luminescence intensity than the cubic samples or the bulk powder

  2. Functional cooperation between FACT and MCM is coordinated with cell cycle and differential complex formation

    Directory of Open Access Journals (Sweden)

    Lin Chih-Li

    2010-02-01

    Full Text Available Abstract Background Functional cooperation between FACT and the MCM helicase complex constitutes an integral step during DNA replication initiation. However, mode of regulation that underlies the proper functional interaction of FACT and MCM is poorly understood. Methods & Results Here we present evidence indicating that such interaction is coordinated with cell cycle progression and differential complex formation. We first demonstrate the existence of two distinct FACT-MCM subassemblies, FACT-MCM2/4/6/7 and FACT-MCM2/3/4/5. Both complexes possess DNA unwinding activity and are subject to cell cycle-dependent enzymatic regulation. Interestingly, analysis of functional attributes further suggests that they act at distinct, and possibly sequential, steps during origin establishment and replication initiation. Moreover, we show that the phosphorylation profile of the FACT-associated MCM4 undergoes a cell cycle-dependent change, which is directly correlated with the catalytic activity of the FACT-MCM helicase complexes. Finally, at the quaternary structure level, physical interaction between FACT and MCM complexes is generally dependent on persistent cell cycle and further stabilized upon S phase entry. Cessation of mitotic cycle destabilizes the complex formation and likely leads to compromised coordination and activities. Conclusions Together, our results correlate FACT-MCM functionally and temporally with S phase and DNA replication. They further demonstrate that enzymatic activities intrinsically important for DNA replication are tightly controlled at various levels, thereby ensuring proper progression of, as well as exit from, the cell cycle and ultimately euploid gene balance.

  3. Dehidroisomerización de n-butano sobre catalizadores bifuncionales tipo Al-MCM-41 y Ga-MCM-41 impregnados con Pt o Ga

    Directory of Open Access Journals (Sweden)

    Dino Brisigotti

    2006-05-01

    Full Text Available A series of bi-functional catalysts was prepared by using Al-MCM-41 and Ga-MCM-41 with Si/Me ratios of 15 and 50 impregnated with 0,5 Wt% of Pt or Ga. The n-butane dehydroisomerization was studied at 773 K. Catalysts based on Pt/Al-MCM-41 were less selective (more hydrogenolyzing than those based on Ga-MCM-41. For the latter, Ga species segregated to extra-framework positions might exercise a kind of geometric effect on the Pt clusters inhibiting hydrogenolysis. The catalyst Ga/Al-MCM-41 showed the closest approach to the ideal dehydroisomerization catalyst.

  4. Comparative studies of Zr-based MCM-41 and MCM-48 mesoporous molecular sieves: Synthesis and physicochemical properties

    International Nuclear Information System (INIS)

    Chen, L.F.; Zhou, X.L.; Norena, L.E.; Wang, J.A.; Navarrete, J.; Salas, P.; Montoya, A.; Del Angel, P.; Llanos, M.E.

    2006-01-01

    Two surfactant-templated synthetic routes are developed for the preparation of new types of mesoporous molecular sieves, Zr-MCM-41 and Zr-MCM-48, using different Si sources but keeping the same zirconium precursor (zirconium-n-propoxide). When fumed silica was used as Si precursor, a Zr-MCM-48 material of cubic structure was formed with a surface area of 654.8 m 2 /g and an unimodal pore diameter distribution. It shows low stability: after calcination at 600 deg. C, the ordered structure was transformed into a relatively disordered worm-like mesostructure with many defects and silanol groups. The use of tetraethyl orthosilicate as Si source led to the formation of a Zr-MCM-41 mesoporous solid, which had good thermal stability and a highly ordered hexagonal arrangement, with a surface area 677.9 m 2 /g and an uniform pore diameter distribution. Fourier transform infrared (FT-IR) characterization and 29 Si NMR analysis confirm that zirconium ions indeed incorporated into the framework of the solid. The in situ FT-IR spectroscopy of pyridine adsorption reveals that both, Lewis and Broensted acid sites, were formed on the surface of these mesoporous materials. The strength and number of the Broensted acid sites of the Zr-MCM-48 solid were greater than those of the Zr-MCM-41, due to a lower degree of condensation reaction during the synthesis that led to more structural defects in the framework and more silanol groups stretching from the solid surface

  5. Pillared MWW zeolites MCM-36 prepared by swelling MCM-22P in concentrated surfactant solutions

    Czech Academy of Sciences Publication Activity Database

    Eliášová, Pavla; Roth, W. J.; Zukal, Arnošt; Kubů, Martin; Pavlatová, Jana

    2012-01-01

    Roč. 179, č. 1 (2012), s. 35-42 ISSN 0920-5861 R&D Projects: GA AV ČR KAN100400701; GA ČR GA104/09/0561 Institutional research plan: CEZ:AV0Z40400503 Keywords : MCM-22 family * MCM-36 * MWW structure Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.980, year: 2012

  6. A dominantly acting murine allele of Mcm4 causes chromosomal abnormalities and promotes tumorigenesis.

    Directory of Open Access Journals (Sweden)

    Bruce N Bagley

    Full Text Available Here we report the isolation of a murine model for heritable T cell lymphoblastic leukemia/lymphoma (T-ALL called Spontaneous dominant leukemia (Sdl. Sdl heterozygous mice develop disease with a short latency and high penetrance, while mice homozygous for the mutation die early during embryonic development. Sdl mice exhibit an increase in the frequency of micronucleated reticulocytes, and T-ALLs from Sdl mice harbor small amplifications and deletions, including activating deletions at the Notch1 locus. Using exome sequencing it was determined that Sdl mice harbor a spontaneously acquired mutation in Mcm4 (Mcm4(D573H. MCM4 is part of the heterohexameric complex of MCM2-7 that is important for licensing of DNA origins prior to S phase and also serves as the core of the replicative helicase that unwinds DNA at replication forks. Previous studies in murine models have discovered that genetic reductions of MCM complex levels promote tumor formation by causing genomic instability. However, Sdl mice possess normal levels of Mcms, and there is no evidence for loss-of-heterozygosity at the Mcm4 locus in Sdl leukemias. Studies in Saccharomyces cerevisiae indicate that the Sdl mutation produces a biologically inactive helicase. Together, these data support a model in which chromosomal abnormalities in Sdl mice result from the ability of MCM4(D573H to incorporate into MCM complexes and render them inactive. Our studies indicate that dominantly acting alleles of MCMs can be compatible with viability but have dramatic oncogenic consequences by causing chromosomal abnormalities.

  7. A dominantly acting murine allele of Mcm4 causes chromosomal abnormalities and promotes tumorigenesis.

    Science.gov (United States)

    Bagley, Bruce N; Keane, Thomas M; Maklakova, Vilena I; Marshall, Jonathon G; Lester, Rachael A; Cancel, Michelle M; Paulsen, Alex R; Bendzick, Laura E; Been, Raha A; Kogan, Scott C; Cormier, Robert T; Kendziorski, Christina; Adams, David J; Collier, Lara S

    2012-01-01

    Here we report the isolation of a murine model for heritable T cell lymphoblastic leukemia/lymphoma (T-ALL) called Spontaneous dominant leukemia (Sdl). Sdl heterozygous mice develop disease with a short latency and high penetrance, while mice homozygous for the mutation die early during embryonic development. Sdl mice exhibit an increase in the frequency of micronucleated reticulocytes, and T-ALLs from Sdl mice harbor small amplifications and deletions, including activating deletions at the Notch1 locus. Using exome sequencing it was determined that Sdl mice harbor a spontaneously acquired mutation in Mcm4 (Mcm4(D573H)). MCM4 is part of the heterohexameric complex of MCM2-7 that is important for licensing of DNA origins prior to S phase and also serves as the core of the replicative helicase that unwinds DNA at replication forks. Previous studies in murine models have discovered that genetic reductions of MCM complex levels promote tumor formation by causing genomic instability. However, Sdl mice possess normal levels of Mcms, and there is no evidence for loss-of-heterozygosity at the Mcm4 locus in Sdl leukemias. Studies in Saccharomyces cerevisiae indicate that the Sdl mutation produces a biologically inactive helicase. Together, these data support a model in which chromosomal abnormalities in Sdl mice result from the ability of MCM4(D573H) to incorporate into MCM complexes and render them inactive. Our studies indicate that dominantly acting alleles of MCMs can be compatible with viability but have dramatic oncogenic consequences by causing chromosomal abnormalities.

  8. Quantitative Proteomics Reveals Dynamic Interactions of the Minichromosome Maintenance Complex (MCM) in the Cellular Response to Etoposide Induced DNA Damage.

    Science.gov (United States)

    Drissi, Romain; Dubois, Marie-Line; Douziech, Mélanie; Boisvert, François-Michel

    2015-07-01

    The minichromosome maintenance complex (MCM) proteins are required for processive DNA replication and are a target of S-phase checkpoints. The eukaryotic MCM complex consists of six proteins (MCM2-7) that form a heterohexameric ring with DNA helicase activity, which is loaded on chromatin to form the pre-replication complex. Upon entry in S phase, the helicase is activated and opens the DNA duplex to recruit DNA polymerases at the replication fork. The MCM complex thus plays a crucial role during DNA replication, but recent work suggests that MCM proteins could also be involved in DNA repair. Here, we employed a combination of stable isotope labeling with amino acids in cell culture (SILAC)-based quantitative proteomics with immunoprecipitation of green fluorescent protein-tagged fusion proteins to identify proteins interacting with the MCM complex, and quantify changes in interactions in response to DNA damage. Interestingly, the MCM complex showed very dynamic changes in interaction with proteins such as Importin7, the histone chaperone ASF1, and the Chromodomain helicase DNA binding protein 3 (CHD3) following DNA damage. These changes in interactions were accompanied by an increase in phosphorylation and ubiquitination on specific sites on the MCM proteins and an increase in the co-localization of the MCM complex with γ-H2AX, confirming the recruitment of these proteins to sites of DNA damage. In summary, our data indicate that the MCM proteins is involved in chromatin remodeling in response to DNA damage. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  9. Preparation of H3PW12O40/MCM-48 and its photocatalytic degradation of pesticides.

    Science.gov (United States)

    Liu, Xia; Li, Yan-zhou; Gan, Qiang; Feng, Chang-gen

    2014-08-01

    A composite catalyst H3PW12O40/MCM-48 was prepared by loading photocatalyst phosphotungstic acid H3PW12O40 (HPW) to molecular sieve MCM-48 by impregnation method, and its structure was characterized by Fourier transform infrared (FT-IR) spectra, small angle X-ray diffraction (XRD) patterns, nitrogen adsorption analysis and High-resolution transmission electron microscopy (HRTEM) analysis. Photocatalytic degradation activities of HPW/MCM-48 against pesticides imidacloprid and paraquat were evaluated under UV radiation (365 nm). The results show that HPW/MCM-48 maintains the mesoprous molecular sieve structure of MCM-48 and the Keggin structure of HPW, while the BET surface area is 793.35 m2 x g(-1), pore volume is 1.46 cm3 x g(-1), average pore diameter is 2.76 nm, suggesting loading HPW on MCM-48 is a considerable way to improve its surface area. After 14 h UV irradiation (365 nm), 57.38% imidacloprid and 63.79% paraquat were degraded by 20 mg HPW/MCM-48 catalyst, while HPW and blank group degraded the two pesticides at the degradation rate of about 25% and 5%, respectively. Implying loading on MCM-48 could greaterly improve the degradation activity of HPW. The reslut of degradation kinetics show that, the degradation process of HPW/MCM-48 fits first order kinetics equation. The rate constant Ka of HPW/MCM-48 toward imidacloprid and paraquat are 0.089 h and 0.117 h, with the half-life t(1/2) of 7.8 h and 5.9 h, respectively.

  10. Comparative studies of Zr-based MCM-41 and MCM-48 mesoporous molecular sieves: Synthesis and physicochemical properties

    Energy Technology Data Exchange (ETDEWEB)

    Chen, L.F. [Departamento de Ciencias Basicas, Universidad Autonoma Metropolitana-A, Av. San Pablo 180, Col. Reynosa-Tamaulipas, 02200 Mexico D.F. (Mexico)]. E-mail: chenlf2001@yahoo.com; Zhou, X.L. [Petroleum Processing Research Center, East China University of Science and Technology, 200237 Shanghai (China); Norena, L.E. [Departamento de Ciencias Basicas, Universidad Autonoma Metropolitana-A, Av. San Pablo 180, Col. Reynosa-Tamaulipas, 02200 Mexico D.F. (Mexico)]. E-mail: lnf@correo.azc.uam.mx; Wang, J.A. [Laboratorio de Catalisis y Materiales, SEPI-ESIQIE, Instituto Politecnico Nacional, Av. Politecnico S/N, Col. Zacatenco, 07738 Mexico D.F. (Mexico); Navarrete, J. [Grupo de Molecular Ingenieria, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas 152, 07730 Mexico D.F. (Mexico); Salas, P. [Grupo de Molecular Ingenieria, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas 152, 07730 Mexico D.F. (Mexico); Montoya, A. [Grupo de Molecular Ingenieria, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas 152, 07730 Mexico D.F. (Mexico); Del Angel, P. [Grupo de Molecular Ingenieria, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas 152, 07730 Mexico D.F. (Mexico); Llanos, M.E. [Grupo de Molecular Ingenieria, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas 152, 07730 Mexico D.F. (Mexico)

    2006-12-30

    Two surfactant-templated synthetic routes are developed for the preparation of new types of mesoporous molecular sieves, Zr-MCM-41 and Zr-MCM-48, using different Si sources but keeping the same zirconium precursor (zirconium-n-propoxide). When fumed silica was used as Si precursor, a Zr-MCM-48 material of cubic structure was formed with a surface area of 654.8 m{sup 2}/g and an unimodal pore diameter distribution. It shows low stability: after calcination at 600 deg. C, the ordered structure was transformed into a relatively disordered worm-like mesostructure with many defects and silanol groups. The use of tetraethyl orthosilicate as Si source led to the formation of a Zr-MCM-41 mesoporous solid, which had good thermal stability and a highly ordered hexagonal arrangement, with a surface area 677.9 m{sup 2}/g and an uniform pore diameter distribution. Fourier transform infrared (FT-IR) characterization and {sup 29}Si NMR analysis confirm that zirconium ions indeed incorporated into the framework of the solid. The in situ FT-IR spectroscopy of pyridine adsorption reveals that both, Lewis and Broensted acid sites, were formed on the surface of these mesoporous materials. The strength and number of the Broensted acid sites of the Zr-MCM-48 solid were greater than those of the Zr-MCM-41, due to a lower degree of condensation reaction during the synthesis that led to more structural defects in the framework and more silanol groups stretching from the solid surface.

  11. Swelling of MCM-56 and MCM-22P with a new medium - surfactant-tetramethylammonium hydroxide mixtures

    Czech Academy of Sciences Publication Activity Database

    Roth, Wieslaw Jerzy; Eliášová, Pavla; Kubů, Martin; Vitvarová, Dana

    2013-01-01

    Roč. 204, APR 2013 (2013), s. 8-14 ISSN 0920-5861 R&D Projects: GA ČR GA203/08/0604; GA ČR GAP106/11/0819 Institutional support: RVO:61388955 Keywords : delaminated zeolite * MCM-56 * MCM-22P Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.309, year: 2013

  12. Paraquat adsorption on NaX and Al-MCM-41.

    Science.gov (United States)

    Rongchapo, Wina; Deekamwong, Krittanun; Loiha, Sirinuch; Prayoonpokarach, Sanchai; Wittayakun, Jatuporn

    2015-01-01

    The aim of this work is to determine paraquat adsorption capacity of zeolite NaX and Al-MCM-41. All adsorbents were synthesized by hydrothermal method using rice husk silica. For Al-MCM-41, aluminum (Al) was added to the synthesis gel of MCM-41 with Al content of 10, 15, 20 and 25 wt%. The faujasite framework type of NaX and mesoporous characteristic of Al-MCM-41 were confirmed by X-ray diffraction. Surface area of all adsorbents determined by N2 adsorption-desorption analysis was higher than 650 m2/g. Al content and geometry were determined by X-ray fluorescence and 27Al nuclear magnetic resonance, respectively. Morphology of Al-MCM-41 were studied by transmission electron microscopy; macropores and defects were observed. The paraquat adsorption experiments were conducted using a concentration range of 80-720 mg/L for NaX and 80-560 mg/L for Al-MCM-41. The paraquat adsorption isotherms from all adsorbents fit well with the Langmuir model. The adsorption capacity of NaX was 120 mg/g-adsorbent. Regarding Al-MCM-41, the 10% Al-MCM-41 exhibited the lowest capacity of 52 mg/g-adsorbent while the other samples had adsorption capacity of 66 mg/g-adsorbent.

  13. Catalytic co-pyrolysis of cellulose and polypropylene over all-silica mesoporous catalyst MCM-41 and Al-MCM-41.

    Science.gov (United States)

    Chi, Yongchao; Xue, Junjie; Zhuo, Jiankun; Zhang, Dahu; Liu, Mi; Yao, Qiang

    2018-08-15

    Fast pyrolysis is one of the most economical and efficient technologies to convert biomass to bio-oil and valuable chemical products. Co-pyrolysis with hydrogen rich materials such as plastics over zeolite catalysts is one of the significant solutions to various problems of bio-oil such as high oxygen content, low heat value and high acid content. This paper studied pyrolysis of cellulose and polypropylene (PP) separately and co-pyrolysis of cellulose and PP over MCM-41 and Al-MCM-41. The pyrolysis over different heating rates (10K/min, 20K/min, 30K/min) was studied by Thermogravimetry Analysis (TGA) and kinetic parameters were obtained by Coats-Redfern method and isoconversion method. TG and DTG data shows that the two catalysts advance the pyrolysis reaction of PP significantly and reduce its peak temperature of DTG curve from 458°C to 341°C. The activation energy of pyrolysis of PP also has a remarkable reduction over the two catalysts. Py-GC/MS method was used to obtain the product distribution of pyrolysis of cellulose and PP separately and co-pyrolysis of cellulose and PP over MCM-41 and Al-MCM-41 at constant temperature of 650°C. Experiment results proved that co-pyrolysis with PP bring significant changes to the product distribution of cellulose. Oxygenated compounds such as furans are decreased, while yields of olefins and aromatics increase greatly. The yield of furans increases with the catalysis of MCM-41 as for the pyrolysis of cellulose and co-pyrolysis, while the yield of olefins and aromatics both experience significant growth over Al-MCM-41, which can be explained by the abundant acid centers in Al-MCM-41. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Aluminum Doped MCM-41 Nanoparticles as Platforms for the Dual Encapsulation of a CO-Releasing Molecule and Cisplatin.

    Science.gov (United States)

    Carmona, Francisco J; Jiménez-Amezcua, Ignacio; Rojas, Sara; Romão, Carlos C; Navarro, Jorge A R; Maldonado, Carmen R; Barea, Elisa

    2017-09-05

    Mesoporous silica Al-MCM-41 nanoparticles have been used, for the first time, as vehicles for the single and dual encapsulation of the cationic CO-releasing molecule (CORM) [Mn(1,4,7-triazacyclononane)(CO) 3 ] + (ALF472 + ) and the well-known antineoplastic drug, cis-[PtCl 2 (NH 3 ) 2 ] (cisplatin). Thus, two new hybrid materials, namely, ALF472@Al-MCM-41 and ALF472-cisplatin@Al-MCM-41, have been isolated and fully characterized. The results reveal that the presence of CORM molecules enhances cisplatin loading 3-fold, yielding a cargo of 0.45 mmol g -1 of ALF472 + and 0.12 mmol g -1 of the platinum complex for ALF472-cisplatin@Al-MCM-41. It is worth noting that ALF472@Al-MCM-41 shows a good dispersion in phosphate buffered saline solution, while the dual hybrid material slightly aggregates in this simulated physiological medium (hydrodynamic size: 112 ± 23 and 336 ± 50 nm, respectively). In addition, both hybrid materials (ALF472@Al-MCM-41 and ALF472-cisplatin@Al-MCM-41) behave as photoactive CO-releasing materials, delivering 0.25 and 0.11 equiv of CO, respectively, after 24 h and exhibiting a more controlled CO delivery than that of the free CORM. Finally, metal leaching studies have confirmed the good retention capacity of Al-MCM-41 toward the potentially toxic manganese fragments (86% of retention after 72 h) as well as the low release of cisplatin (ca. 7% after 72 h).

  15. Synthesis and characterization of mesoporous Si-MCM-41 materials ...

    Indian Academy of Sciences (India)

    Administrator

    The poten- tial use of Al-MCM-41 and 12TPA-MCM-41 as solid acid catalysts has been explored and compared by study- ... such as difficulty in handling, causing an acidic waste water ... been supported onto MCM-41 by process of anchoring.

  16. Synthesis and characterization of bulky mesoporous silica Pd-MCM-41

    International Nuclear Information System (INIS)

    Nagata, Hidezumi; Nakahira, Atsushi; Hirao, Norie; Baba, Yuji; Onoki, Takamasa; Yamasaki, Yuki

    2008-01-01

    Bulky palladium catalyst supported on mesoporous silica MCM-41 (Pd-MCM-41) was successfully synthesized by hydrothermal hot-pressing method. In this study, the structure of the palladium species in Pd-MCM-41 bulk before and after heat-treatment process was revealed by X-ray diffraction (XRD), X-ray absorption near edge structure (XANES) and transmission electron microscopy (TEM). Also, the microstructure and mesoporous property of Pd-MCM-41 bulk was discussed. As a result, it was revealed that these dense Pd-MCM-41 bulks possessed a high surface area of over 1000 m 2 /g and the structure of palladium of Pd-MCM-41 bulk is almost equal to palladium (0) metal. (author)

  17. MCM Polarimetric Radiometers for Planar Arrays

    Science.gov (United States)

    Kangaslahti, Pekka; Dawson, Douglas; Gaier, Todd

    2007-01-01

    A polarimetric radiometer that operates at a frequency of 40 GHz has been designed and built as a prototype of multiple identical units that could be arranged in a planar array for scientific measurements. Such an array is planned for use in studying the cosmic microwave background (CMB). All of the subsystems and components of this polarimetric radiometer are integrated into a single multi-chip module (MCM) of substantially planar geometry. In comparison with traditional designs of polarimetric radiometers, the MCM design is expected to greatly reduce the cost per unit in an array of many such units. The design of the unit is dictated partly by a requirement, in the planned CMB application, to measure the Stokes parameters I, Q, and U of the CMB radiation with high sensitivity. (A complete definition of the Stokes parameters would exceed the scope of this article. In necessarily oversimplified terms, I is a measure of total intensity of radiation, while Q and U are measures of the relationships between the horizontally and vertically polarized components of radiation.) Because the sensitivity of a single polarimeter cannot be increased significantly, the only way to satisfy the high-sensitivity requirement is to make a large array of polarimeters that operate in parallel. The MCM includes contact pins that can be plugged into receptacles on a standard printed-circuit board (PCB). All of the required microwave functionality is implemented within the MCM; any required supporting non-microwave ("back-end") electronic functionality, including the provision of DC bias and control signals, can be implemented by standard PCB techniques. On the way from a microwave antenna to the MCM, the incoming microwave signal passes through an orthomode transducer (OMT), which splits the radiation into an h + i(nu) beam and an h - i(nu) beam (where, using complex-number notation, h denotes the horizontal component, nu denotes the vertical component, and +/-i denotes a +/-90deg phase

  18. Interaction of RECQ4 and MCM10 is important for efficient DNA replication origin firing in human cells

    DEFF Research Database (Denmark)

    Kliszczak, Maciej; Sedlackova, Hana; Pitchai, Ganesha P

    2015-01-01

    DNA replication is a highly coordinated process that is initiated at multiple replication origins in eukaryotes. These origins are bound by the origin recognition complex (ORC), which subsequently recruits the Mcm2-7 replicative helicase in a Cdt1/Cdc6-dependent manner. In budding yeast, two...... essential replication factors, Sld2 and Mcm10, are then important for the activation of replication origins. In humans, the putative Sld2 homolog, RECQ4, interacts with MCM10. Here, we have identified two mutants of human RECQ4 that are deficient in binding to MCM10. We show that these RECQ4 variants...... are able to complement the lethality of an avian cell RECQ4 deletion mutant, indicating that the essential function of RECQ4 in vertebrates is unlikely to require binding to MCM10. Nevertheless, we show that the RECQ4-MCM10 interaction is important for efficient replication origin firing....

  19. Synthesis, characterization, and near-infrared luminescent properties of the ternary thulium complex covalently bonded to mesoporous MCM-41

    International Nuclear Information System (INIS)

    Feng Jing; Song Shuyan; Xing Yan; Zhang Hongjie; Li Zhefeng; Sun Lining; Guo Xianmin; Fan Weiqiang

    2009-01-01

    The crystal structure of a ternary Tm(DBM) 3 phen complex (DBM=dibenzoylmethane; phen=1, 10-phenanthroline) and the synthesis of hybrid mesoporous material in which the complex covalently bonded to mesoporous MCM-41 are reported. Crystal data: Tm(DBM) 3 phen C 59 H 47 N 2 O 7 Tm, monoclinic, P21/c, a=19.3216(12) A, b=10.6691(7) A, c=23.0165(15) A, α=90 deg., β=91.6330(10) deg., γ=90 deg., V=4742.8(5) A 3 , Z=4. The properties of the Tm(DBM) 3 phen complex and the corresponding hybrid mesoporous material [Tm(DBM) 3 phen-MCM-41] have been studied. The results reveal that the Tm(DBM) 3 phen complex is successfully covalently bonded to MCM-41. Both Tm(DBM) 3 phen complex and Tm(DBM) 3 phen-MCM-41 display typical near-infrared (NIR) luminescence upon excitation at the maximum absorption of the ligands, which contributes to the efficient energy transfer from the ligands to the Tm 3+ ion, an antenna effect. The full width at half maximum (FWHM) centered at 1474 nm in the emission spectrum of Tm(DBM) 3 phen-MCM-41 is 110 nm, which is the potential candidate of broadening amplification band from C band (1530-1560 nm) to S + band (1450-1480 nm) in optical area. - Graphical abstract: The crystal structure of Tm(DBM) 3 phen complex (DBM=dibenzoylmethane; phen=1, 10-phenanthroline). The complex is successfully covalently bonded to MCM-41 (Tm(DBM) 3 phen-MCM-41). After ligand-mediated excitation, the emission spectrum of Tm(DBM) 3 phen-MCM-41 shows the bands 802 and 1474 nm. The FWHM of the 1474-nm band for Tm(DBM) 3 phen-MCM-41 is 110 nm, such a broad spectrum enables a wide gain bandwidth for optical amplification

  20. Pixel detector modules using MCM-D technology

    CERN Document Server

    Grah, C

    2001-01-01

    For the upcoming ATLAS-experiment at CERN it is planned to build a large area pixel detector, providing more than 100*10/sup 6/ sensor cells. For the innermost layer, the B-physics layer, it is planned to use MCM-D technology to perform the signal interconnections and power distribution on the modules. Focus of this paper is to give an introduction to this technology and present measurements on single chip MCM-D assemblies and a full scale MCM-D module prototype. (10 refs).

  1. Synthesis of Dicyclopentadiene Oligomer Over Nanoporous Al-MCM-41 Catalysts.

    Science.gov (United States)

    Park, Eunseo; Kim, Jinhan; Yim, Jin-Heong; Han, Jeongsik; Kwon, Tae Soo; Park, Y K; Jeon, Jong-Ki

    2016-05-01

    One step reaction composed of DCPD oligomerization and DCPD oligomer isomerization was investigated over nanoporous Al-MCM-41 catalysts. The effects of aluminum grafting over MCM-41 on the catalyst characteristics were studied with respect to the synthesis of TCPD isomer. Physical and chemical properties of the catalysts were analyzed by N2 adsorption, temperature-programmed desorption of ammonia, and infrared spectroscopy of adsorbed pyridine. The overall number of acid sites as well as the number of Lewis acid sites increased with increasing of aluminum content over MCM-41. When utilizing MCM-41 and Al-MCM-41 as the catalyst, DCPD oligomerization reaction activity greatly increased compared to the thermal reaction. The highest TCPD isomer selectivity over the Al-MCM-41 catalyst with the highest aluminum content could be ascribed to the largest amount of acid sites. This study showed an increased level of TCPD isomer selectivity by an increasing level of Lewis acid sites through aluminum addition over MCM-41.

  2. Evaluation of Optimal Pore Size of (3-Aminopropyltriethoxysilane Grafted MCM-41 for Improved CO2 Adsorption

    Directory of Open Access Journals (Sweden)

    Zhilin Liu

    2015-01-01

    Full Text Available An array of new MCM-41 with substantially larger average pore diameters was synthesized through adding 1,3,5-trimethylbenzene (TMB as the swelling agent to explore the effect of pore size on final adsorbent properties. The pore expanded MCM-41 was also grafted with (3-Aminopropyltriethoxysilane (APTES to determine the optimal pore size for CO2 adsorption. The pore-expanded mesoporous MCM-41s showed relatively less structural regularity but significant increments of pore diameter (4.64 to 7.50 nm; the fraction of mesopore volume also illustrated an increase. The adsorption heat values were correlated with the order of the adsorption capacities for pore expanded MCM-41s. After amine functionalization, the adsorption capacities and heat values showed a significant increase. APTES-grafted pore-expanded MCM-41s depicted a high potential for CO2 capture regardless of the major drawback of the high energy required for regeneration.

  3. The viability of MCM-41 as separator in secondary alkaline cells

    Science.gov (United States)

    Meskon, S. R.; Othman, R.; Ani, M. H.

    2018-01-01

    The viability of MCM-41 membrane as a separator material in secondary alkaline cell is investigated. The inorganic membrane was employed in an alkaline nickel-zinc system. MCM-41 mesoporous material consists of arrays of hexagonal nano-pore channels. The membrane was synthesized using sol-gel route from parent solution comprising of quarternary ammonium surfactant, cethyltrimethylammonium bromide C16H33(CH3)3NBr (CTAB), hydrochloric acid (HCl), deionized water (H2O), ethanol (C2H5OH), and tetraethylortosilicate (TEOS). Both the anodic zinc/zinc oxide and cathodic nickel hydroxide electrodeposited film were coated with MCM-41 membrane. The Ni/MCM-41/Zn alkaline cell was then subjected to 100-cycle durability test and the structural stability of MCM-41 separator throughout the progression of the charge-discharge cycles is studied. X-ray diffraction (XRD) analysis on the dismantled cell shows that MCM-41 began to transform to lamellar MCM-50 on the 5th cycle and transformed almost completely on the 25th cycle. The phase transformation of MCM-41 hexagonal structure into gel-like MCM-50 prevents the mesoporous cell separator from diminished in the caustic alkaline surround. This work has hence demonstrated MCM-41 membrane is viable to be employed in secondary alkaline cells.

  4. Synthesis and characterization of mesoporous Mn-MCM-41 materials

    International Nuclear Information System (INIS)

    Saladino, Maria Luisa; Kraleva, Elka; Todorova, Silvia; Spinella, Alberto; Nasillo, Giorgio; Caponetti, Eugenio

    2011-01-01

    Highlights: · Manganese MCM-41 as catalyst. · Influence of pH on the structure of MCM-41. · Influence of manganese on the structure and activity of Mn-MCM-41. - Abstract: MCM-41 has been synthesized at two different pH using cetyl-trimethylammonium bromide (CTAB) surfactant as template and adding the silica precursor to aqueous solutions containing CTAB. The obtained solids were calcined at 600 deg. C for 4 h. Mn-MCM-41 powders with different Mn/Si molar ratios were prepared using the incipient wetness method, followed by calcination at 550 deg. C for 5 h. At the end of the impregnation process the powders colour changed from white to brown whose intensity depends on manganese quantity. The materials characterization was performed by X-ray diffraction, N 2 adsorption, 29 Si Cross Polarization-Magic Angle Spinning NMR, and X-ray Photoelectron Spectroscopy. The effects of the manganese quantity and of the structural characteristic of the MCM-41 support were studied. The catalytic activity of the prepared systems was evaluated in a complete n-hexane oxidation.

  5. Ablation of MCM10 using CRISPR/Cas9 restrains the growth and migration of esophageal squamous cell carcinoma cells through inhibition of Akt signaling

    Directory of Open Access Journals (Sweden)

    Yan J

    2018-06-01

    Full Text Available Jie Yan,1,2 Pan Du,3 Yongxu Jia,2 Zhiwei Chang,2 Silin Gan,4 Xiaohan Xu,5 Yaohe Wang,3 Yanru Qin,2 Quancheng Kan1 1Department of Gastroenterology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China; 2Department of Oncology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China; 3National Center for International Research in Cell and Gene Therapy, Sino-British Research Centre for Molecular Oncology, Zhengzhou University, Zhengzhou, China; 4Department of Hematology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China; 5Department of Anesthesiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China Introduction: Minichromosome maintenance 10 (MCM10 is deregulated in several malignancies including cervical cancer and urothelial carcinoma. However, the expression and biologic role of MCM10 in esophageal squamous cell carcinoma (ESCC is still unknown. Methods: In this study, we performed immunohistochemistry and real-time polymerase chain reaction (PCR analysis to examine the expression of MCM10 in ESCC and adjacent normal esophageal tissues. The associations of MCM10 expression with clinicopathologic parameters of ESCC were analyzed. Ablation of MCM10 through the CRISPR/Cas9 technology was conducted and its impact on ESCC cell growth and migration was investigated. Results: The mRNA and protein expression levels of MCM10 were significantly greater in ESCC than in normal tissues (P<0.001. The expression of MCM10 was significantly associated with age at diagnosis (P=0.033, but not with gender, differentiation grade, invasion status, or tumor–node–metastasis (TNM stage. Knockout of MCM10 significantly suppressed the proliferation, colony formation, and migration capacity of EC109 ESCC cells, compared to control cells harboring wild-type MCM10. Mechanistically, MCM10 depletion markedly reduced the phosphorylation of Akt. Overexpression of constitutively active Akt

  6. Surface Properties of Al-Functionalized Mesoporous MCM-41 and the Melting Behavior of Water in Al-MCM-41 Nanopores.

    Science.gov (United States)

    Sterczyńska, Angelina; Deryło-Marczewska, Anna; Zienkiewicz-Strzałka, Małgorzata; Śliwińska-Bartkowiak, Małgorzata; Domin, Kamila

    2017-10-24

    We report an experimental investigation of structural and adhesive properties for Al-containing mesoporous MCM-41 and MCM-41 surfaces. In this work, highly ordered hexagonal mesoporous structures of aluminosilica with two different Si/Al molar ratios equal to 50 and 80 and silica samples were studied; Al was incorporated into the MCM-41 structures using the direct synthesis method, with CTAB as a surfactant. The incorporation of aluminum was evidenced simultaneously without any change in the hexagonal arrangement of cylindrical mesopores. The porous materials were examined by techniques such as low-temperature nitrogen sorption, energy-dispersive spectroscopy, and scanning and transmission electron microscopy. Surface properties were determined through X-ray photoelectron spectroscopy, potentiometric titration, and static contact angle measurements. It was shown that an increase in surface acidity leads to an increase in the wetting energy of the surface. To investigate the influence of acidity on the confinement effects, the melting behavior of water in Al-MCM-41 and MCM-41 with the same pore size was determined by using dielectric relaxation spectroscopy and differential scanning calorimetry methods. We found that the melting-point depression of water in pores is larger in the functionalized pores than in pure silica pores of the same pore diameter.

  7. How MCM loading and spreading specify eukaryotic DNA replication initiation sites [version 1; referees: 4 approved

    Directory of Open Access Journals (Sweden)

    Olivier Hyrien

    2016-08-01

    Full Text Available DNA replication origins strikingly differ between eukaryotic species and cell types. Origins are localized and can be highly efficient in budding yeast, are randomly located in early fly and frog embryos, which do not transcribe their genomes, and are clustered in broad (10-100 kb non-transcribed zones, frequently abutting transcribed genes, in mammalian cells. Nonetheless, in all cases, origins are established during the G1-phase of the cell cycle by the loading of double hexamers of the Mcm 2-7 proteins (MCM DHs, the core of the replicative helicase. MCM DH activation in S-phase leads to origin unwinding, polymerase recruitment, and initiation of bidirectional DNA synthesis. Although MCM DHs are initially loaded at sites defined by the binding of the origin recognition complex (ORC, they ultimately bind chromatin in much greater numbers than ORC and only a fraction are activated in any one S-phase. Data suggest that the multiplicity and functional redundancy of MCM DHs provide robustness to the replication process and affect replication time and that MCM DHs can slide along the DNA and spread over large distances around the ORC. Recent studies further show that MCM DHs are displaced along the DNA by collision with transcription complexes but remain functional for initiation after displacement. Therefore, eukaryotic DNA replication relies on intrinsically mobile and flexible origins, a strategy fundamentally different from bacteria but conserved from yeast to human. These properties of MCM DHs likely contribute to the establishment of broad, intergenic replication initiation zones in higher eukaryotes.

  8. Simultaneous measurement of passage through the restriction point and MCM loading in single cells

    Science.gov (United States)

    Håland, T. W.; Boye, E.; Stokke, T.; Grallert, B.; Syljuåsen, R. G.

    2015-01-01

    Passage through the Retinoblastoma protein (RB1)-dependent restriction point and the loading of minichromosome maintenance proteins (MCMs) are two crucial events in G1-phase that help maintain genome integrity. Deregulation of these processes can cause uncontrolled proliferation and cancer development. Both events have been extensively characterized individually, but their relative timing and inter-dependence remain less clear. Here, we describe a novel method to simultaneously measure MCM loading and passage through the restriction point. We exploit that the RB1 protein is anchored in G1-phase but is released when hyper-phosphorylated at the restriction point. After extracting cells with salt and detergent before fixation we can simultaneously measure, by flow cytometry, the loading of MCMs onto chromatin and RB1 binding to determine the order of the two events in individual cells. We have used this method to examine the relative timing of the two events in human cells. Whereas in BJ fibroblasts released from G0-phase MCM loading started mainly after the restriction point, in a significant fraction of exponentially growing BJ and U2OS osteosarcoma cells MCMs were loaded in G1-phase with RB1 anchored, demonstrating that MCM loading can also start before the restriction point. These results were supported by measurements in synchronized U2OS cells. PMID:26250117

  9. The MCM Helicase Motor of the Eukaryotic Replisome.

    Science.gov (United States)

    Abid Ali, Ferdos; Costa, Alessandro

    2016-05-08

    The MCM motor of the CMG helicase powers ahead of the eukaryotic replication machinery to unwind DNA, in a process that requires ATP hydrolysis. The reconstitution of DNA replication in vitro has established the succession of events that lead to replication origin activation by the MCM and recent studies have started to elucidate the structural basis of duplex DNA unwinding. Despite the exciting progress, how the MCM translocates on DNA remains a matter of debate. Copyright © 2016. Published by Elsevier Ltd.

  10. A study on hydrogen-storage behaviors of nickel-loaded mesoporous MCM-41.

    Science.gov (United States)

    Park, Soo-Jin; Lee, Seul-Yi

    2010-06-01

    The objective of the present work was to investigate the possibility of improving the hydrogen-storage capacity of mesoporous MCM-41 containing nickel (Ni) oxides (Ni/MCM-41). The MCM-41 and Ni/MCM-41 were prepared using a hydrothermal process as a function of Ni content (2, 5, and 10 wt.% in the MCM-41). The surface functional groups of the Ni/MCM-41 were identified by Fourier transform infrared spectroscopy (FTIR). The structure and morphology of the Ni/MCM-41 were characterized by X-ray diffraction (XRD) and field emission transmission electron microscopy (FE-TEM). XRD results showed a well-ordered hexagonal pore structure; FE-TEM also revealed, as a complementary technique, the structure and pore size. The textural properties of the Ni/MCM-41 were analyzed using N(2) adsorption isotherms at 77 K. The hydrogen-storage capacity of the Ni/MCM-41 was evaluated at 298 K/100 bar. It was found that the presence of Ni on mesoporous MCM-41 created hydrogen-favorable sites that enhanced the hydrogen-storage capacity by a spillover effect. Furthermore, it was concluded that the hydrogen-storage capacity was greatly influenced by the amount of nickel oxide, resulting in a chemical reaction between Ni/MCM-41 and hydrogen molecules. Crown Copyright © 2010. Published by Elsevier Inc. All rights reserved.

  11. Hydroisomerization of n-dodecane over Pt/Al-MCM-48 catalysts.

    Science.gov (United States)

    Yun, Soyoung; Park, Young-Kwon; Jeong, Soon-Yong; Han, Jeongsik; Jeon, Jong-Ki

    2014-04-01

    The objective of this study is to evaluate the catalytic potential of Pt/Al-MCM-48 catalysts in hydroisomerization of n-dodecane. The effects of the Si/Al ratio and platinum loading on the acid characteristics of Al-MCM-48 and the catalytic performance in n-dodecane hydroisomerization were analyzed. The catalysts were characterized by X-ray diffraction, nitrogen adsorption, infrared spectroscopy of pyridine adsorption, and temperature programmed desorption of ammonia. The number of weak strength acid sites on Al-MCM-48 increased with 0.5 wt% platinum loading. The weak strength acid sites of Pt/Al-MCM-48 catalysts were ascribed to Lewis acid sites, which can be confirmed by NH3-TPD and FTIR spectra of pyridine adsorption. Iso-dodecane can be produced with high selectivity in n-dodecane hydrosisomerization over Pt/Al-MCM-48 catalysts. This is attributed to the mild acidic properties of Pt/Al-MCM-48 catalysts.

  12. Characterization of the MCM homohexamer from the thermoacidophilic euryarchaeon Picrophilus torridus

    Science.gov (United States)

    Goswami, Kasturi; Arora, Jasmine; Saha, Swati

    2015-01-01

    The typical archaeal MCM exhibits helicase activity independently in vitro. This study characterizes MCM from the euryarchaeon Picrophilus torridus. While PtMCM hydrolyzes ATP in DNA-independent manner, it displays very poor ability to unwind DNA independently, and then too only under acidic conditions. The protein exists stably in complex with PtGINS in whole cell lysates, interacting directly with PtGINS under neutral and acidic conditions. GINS strongly activates MCM helicase activity, but only at low pH. In consonance with this, PtGINS activates PtMCM-mediated ATP hydrolysis only at low pH, with the amount of ATP hydrolyzed during the helicase reaction increasing more than fifty-fold in the presence of GINS. While the stimulation of MCM-mediated helicase activity by GINS has been reported in MCMs from P.furiosus, T.kodakarensis, and very recently, T.acidophilum, to the best of our knowledge, this is the first report of an MCM helicase demonstrating DNA unwinding activity only at such acidic pH, across all archaea and eukaryotes. PtGINS may induce/stabilize a conducive conformation of PtMCM under acidic conditions, favouring PtMCM-mediated DNA unwinding coupled to ATP hydrolysis. Our findings underscore the existence of divergent modes of replication regulation among archaea and the importance of investigating replication events in more archaeal organisms. PMID:25762096

  13. Synthesis and adsorption investigations of zeolites MCM-22 and MCM-49 modified by alkali metal cations

    Czech Academy of Sciences Publication Activity Database

    Pawlesa, Justyna; Zukal, Arnošt; Čejka, Jiří

    2007-01-01

    Roč. 13, 3-4 (2007), s. 257-265 ISSN 0929-5607 Grant - others:DeSSANS(XE) SES6-CT-2005-020133; INDENS(XE) MRTN-CT-2004-005503 Institutional research plan: CEZ:AV0Z40400503 Source of funding: R - rámcový projekt EK ; R - rámcový projekt EK Keywords : MCM-22 zeolite * MCM-49 zeolite * alkali metal cation exchange * N2 and CO2 adsorption Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.880, year: 2007

  14. Influence of MCM-41 particle on mechanical and morphological behavior of polypropylene

    International Nuclear Information System (INIS)

    Wang Na; Shao Yawei; Shi Zhaoxin; Zhang Jing; Li Hongwei

    2008-01-01

    This study investigates the effects of different types of nanoparticles and amount of nanoparticles on morphology and mechanical performance of polypropylene (PP) composites. Three different types of nanoparticles, namely mesoporous MCM-41 (without template), mesoporous MCM-41 (with template), and mesoporous MCM-41, whose pore channels were filled with different flexible polymer inside the pore channels with the aid of supercritical CO 2 are considered. PP composites containing (0.5-5 wt.%) mesoporous MCM-41 were prepared by compounding. The tensile properties of the composites determined as a function of the filler loading and the different types of nanoparticles are found to vary with the different interface between different fillers and the matrix. The results of tensile tests showed that different flexible polymer filled mesoporous MCM-41 nanoparticles could simultaneously provide PP with strengthening and toughening effects at rather low filler content (0.5 wt.%). Scanning electron microscopy studies revealed a good dispersion of the MCM-41-S-PMMA and MCM-41-S-PS particles in the PP matrix and the enhancement of the interface between PP and MCM-41 are obtained

  15. Application of mesoporous Al-MCM-48 material to the conversion of lignin.

    Science.gov (United States)

    Lee, Hyung Won; Lee, In-Gu; Park, Sung Hoon; Jeon, Jong-Ki; Suh, Dong Jin; Jung, Jinho; Park, Young-Kwon

    2014-04-01

    Al-MCM-48 was applied to the catalytic pyrolysis of lignin for the first time. The pyrolysis reaction and in-situ product were analyzed by pyrolysis gas chromatography/mass spectrometry. The main products of the non-catalytic pyrolysis of lignin were phenols. The use of Al-MCM-48 increased the production of light phenols considerably. The yields of high-value-added compounds, such as hydrocarbons and aromatics, were also increased by catalytic upgrading. Al-MCM-48 is believed to promote cracking, aromatization and deoxygenation, such as decarbonylation. On the other hand, Si-MCM-48, which has no acid sites, showed lower deoxygenation efficiency than Al-MCM-48. Al-MCM-48 could be regenerated by calcining in air.

  16. Cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of the central zinc-binding domain of the human Mcm10 DNA-replication factor

    International Nuclear Information System (INIS)

    Jung, Nam Young; Bae, Won Jin; Chang, Jeong Ho; Kim, Young Chang; Cho, Yunje

    2008-01-01

    Mcm10 is a highly conserved nuclear protein that plays a key role in the initiation and elongation processes of DNA replication by providing a physical link between the Mcm2–7 complex and DNA polymerases. In this study, the central domain of human Mcm10 was crystallized using the hanging-drop vapour-diffusion method in the presence of PEG 3350. The initiation of eukaryotic DNA replication requires the tightly controlled assembly of a set of replication factors. Mcm10 is a highly conserved nuclear protein that plays a key role in the initiation and elongation processes of DNA replication by providing a physical link between the Mcm2–7 complex and DNA polymerases. The central domain, which contains the CCCH zinc-binding motif, is most conserved within Mcm10 and binds to DNA and several proteins, including proliferative cell nuclear antigen. In this study, the central domain of human Mcm10 was crystallized using the hanging-drop vapour-diffusion method in the presence of PEG 3350. An X-ray diffraction data set was collected to a resolution of 2.6 Å on a synchrotron beamline. The crystals formed belonged to space group R3, with unit-cell parameters a = b = 99.5, c = 133.0 Å. According to Matthews coefficient calculations, the crystals were predicted to contain six MCM10 central domain molecules in the asymmetric unit

  17. Epoxidation of limonene over Ti MCM 41 and Ti BETA

    International Nuclear Information System (INIS)

    Cubillos Lobo, Jairo Antonio; Gonzalez Rodriguez, Lina Maria; Montes de Correa, Consuelo

    2002-01-01

    Ti MCM 41 were synthesized and evaluated in the epoxidation of limonene, using peroxide of hydrogen (H 2 O) as agent oxidizer. The characteristic hexagonal phase of Ti MCM 41 was obtained by heating the precursor gel during three days at 100 centigrade degrees. Further heating up to ten days leads to a decrease of this phase. The increase (Ti) in the synthesis gel also decreases that phase. The increase of Ti in the synthesis gel also decreases that phase UV VIS and FTIR spectroscopy indicates that Ti was incorporated in the lattice of Ti MCM 41 as well as, in Ti BETA. SEM micrographs of Ti MCM 41 show that the morphology changes with the Ti loading. Ti MCM 41 was most active than Ti BETA for limonene epoxidation even though both show high selectivity to epoxides

  18. Spherical V-Fe-MCM-48: The Synthesis, Characterization and Hydrothermal Stability.

    Science.gov (United States)

    Qian, Wang; Wang, Haiqing; Chen, Jin; Kong, Yan

    2015-04-14

    Spherical MCM-48 mesoporous sieve co-doped with vanadium and iron was successfully synthesized via one-step hydrothermal method. The material was characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption isotherms, inductively coupled plasma (ICP), scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance UV-vis spectra, and X-ray photoelectron spectra (XPS) techniques. Results indicated that the V-Fe-MCM-48 showed an ordered 3D cubic mesostructure with spherical morphology, narrow pore size distribution and high specific surface area. Most of vanadium and iron atoms existing as tetrahedral V 4+ and Fe 3+ species were co-doped into the silicate framework. The particle sizes of V-Fe-MCM-48 were smaller and the specific area was much higher than those of of V-MCM-48. Additionally, the synthesized V-Fe-MCM-48 exhibited improved hydrothermal stability compared with the pure MCM-48.

  19. Proliferation marker pKi-67 occurs in different isoforms with various cellular effects.

    Science.gov (United States)

    Schmidt, Mirko H H; Broll, Rainer; Bruch, Hans-Peter; Finniss, Susan; Bögler, Oliver; Duchrow, Michael

    2004-04-15

    The Ki-67 antigen, pKi-67, is a commonly used proliferation marker in research and pathology. It has been recognized that the protein exists in two different splice variants that differ in one exon. In the current work, we present three new splice variants of human pKi-67 consisting of two naturally occurring isoforms and one atypical version. Additionally, data is presented indicating that alternative splicing of the pKi-67 N-terminus is common in tumor cell lines. Analyzing 93 tissues mainly consisting of brain tumor specimens, we found evidence that long and short isoform can be expressed independently of each other. Induction of mitosis in human peripheral blood mononuclear cells revealed that short pKi-67 appears earlier in the cell cycle than the long isoform and reaches its expression maximum when transcription of the latter sets in. Finally, transfection of mammalian culture cells with exon 7 (specific for the long pKi-67 isoform and not present in the short isoform) in a tetracycline regulated expression system decreased the rate of cell proliferation without affecting the cell cycle. In summary, we present evidence that the pKi-67 N-terminus is differentially spliced resulting in at least five different isoforms with different functions. Copyright 2004 Wiley-Liss, Inc.

  20. SiC-dopped MCM-41 materials with enhanced thermal and hydrothermal stabilities

    International Nuclear Information System (INIS)

    Wang, Yingyong; Jin, Guoqiang; Tong, Xili; Guo, Xiangyun

    2011-01-01

    Graphical abstract: Novel SiC-dopped MCM-41 materials were synthesized by adding silicon carbide suspension in the molecular sieve precursor solvent followed by in situ hydrothermal synthesis. The dopped materials have a wormhole-like mesoporous structure and exhibit enhanced thermal and hydrothermal stabilities. Highlights: → SiC-dopped MCM-41 was synthesized by in situ hydrothermal synthesis of molecular sieve precursor combined with SiC. → The dopped MCM-41 materials show a wormhole-like mesoporous structure. → The thermal stability of the dopped materials have an increment of almost 100 o C compared with the pure MCM-41. → The hydrothermal stability of the dopped materials is also better than that of the pure MCM-41. -- Abstract: SiC-dopped MCM-41 mesoporous materials were synthesized by the in situ hydrothermal synthesis, in which a small amount of SiC was added in the precursor solvent of molecular sieve before the hydrothermal treatment. The materials were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, N 2 physical adsorption and thermogravimetric analysis, respectively. The results show that the thermal and hydrothermal stabilities of MCM-41 materials can be improved obviously by incorporating a small amount of SiC. The structure collapse temperature of SiC-dopped MCM-41 materials is 100 o C higher than that of pure MCM-41 according to the differential scanning calorimetry analysis. Hydrothermal treatment experiments also show that the pure MCM-41 will losses it's ordered mesoporous structure in boiling water for 24 h while the SiC-dopped MCM-41 materials still keep partial porous structure.

  1. Immunohistochemical Expression of MCM-2 in Oral Epithelial Dysplasias.

    Science.gov (United States)

    Zakaria, Samar H; Farag, Heba A; Khater, Dina S

    2016-03-17

    Oral cancer is one of the most frequent cancers in the world. It arises from epithelial dysplasia. Hence, identifying these lesions in an early stage could prevent their malignant transformation. The aim of the present work was to assess the cell proliferative activity of minichromosome maintenance protein (MCM-2) in oral epithelial dysplastic lesions and to correlate the results with different grades of epithelial dysplasia in an attempt to use MCM-2 in the early detection of malignancy. MCM-2 expression was determined by the nuclear count in a total of 30 oral epithelial dysplastic specimens roughly classified into 10 cases of mild, moderate, and severe dysplasia. Five cases of early invasive squamous-cell carcinomas and 5 cases of epithelial hyperplasia were also included. The MCM-2 immunostaining was found to increase gradually from mild to moderate to severe dysplasia and reached its maximum value in early invasive squamous cell carcinoma. MCM-2 is of prognostic value in cases of oral dysplasia that have a tendency to undergo malignant transformation.

  2. Studies on MCM-D pixel-detector-modules

    CERN Document Server

    Flick, T; Gerlach, P; Grah, C; Mättig, P; Rohe, T

    2003-01-01

    In the context of the development of the ATLAS-pixel-detector, a technology for building up the high density interconnects has been studied, the MCM-D (multichip module deposited) technology. Results of building up first assemblies have been reported. MCM-D technology allows to build up assemblies with uniformly segmented sensors. Especially the use of 'equal-sized(-bricked)' sensor geometry has been studied.

  3. MCM: one ring to rule them all.

    Science.gov (United States)

    Deegan, Tom D; Diffley, John F X

    2016-04-01

    Precise replication of the eukaryotic genome is achieved primarily through strict regulation of the enzyme responsible for DNA unwinding, the replicative helicase. The motor of this helicase is a hexameric AAA+ ATPase called MCM. The loading of MCM onto DNA and its subsequent activation and disassembly are each restricted to separate cell cycle phases; this ensures that a functional replisome is only built once at any replication origin. In recent years, biochemical and structural studies have shown that distinct conformational changes in MCM, each requiring post-translational modifications and/or the activity of other replication proteins, define the various stages of the chromosome replication cycle. Here, we review recent progress in this area. Copyright © 2016. Published by Elsevier Ltd.

  4. Characterization of a Novel MMS-Sensitive Allele of Schizosaccharomyces pombe mcm4+

    Science.gov (United States)

    Ranatunga, Nimna S.; Forsburg, Susan L.

    2016-01-01

    The minichromosome maintenance (MCM) complex is the conserved helicase motor of the eukaryotic replication fork. Mutations in the Mcm4 subunit are associated with replication stress and double strand breaks in multiple systems. In this work, we characterize a new temperature-sensitive allele of Schizosaccharomyces pombe mcm4+. Uniquely among known mcm4 alleles, this mutation causes sensitivity to the alkylation damaging agent methyl methanesulfonate (MMS). Even in the absence of treatment or temperature shift, mcm4-c106 cells show increased repair foci of RPA and Rad52, and require the damage checkpoint for viability, indicating genome stress. The mcm4-c106 mutant is synthetically lethal with mutations disrupting fork protection complex (FPC) proteins Swi1 and Swi3. Surprisingly, we found that the deletion of rif1+ suppressed the MMS-sensitive phenotype without affecting temperature sensitivity. Together, these data suggest that mcm4-c106 destabilizes replisome structure. PMID:27473316

  5. Transition metal oxide loaded MCM catalysts for photocatalytic ...

    Indian Academy of Sciences (India)

    Transition metal oxide (TiO2, Fe2O3, CoO) loaded MCM-41 and MCM-48 were synthesized by a two-step .... washed consecutively with water and ethanol, and cal- cined at 823 K for 5 .... conversion was observed in 1 h when the reaction was.

  6. Reversal of DDK-Mediated MCM Phosphorylation by Rif1-PP1 Regulates Replication Initiation and Replisome Stability Independently of ATR/Chk1.

    Science.gov (United States)

    Alver, Robert C; Chadha, Gaganmeet Singh; Gillespie, Peter J; Blow, J Julian

    2017-03-07

    Dbf4-dependent kinases (DDKs) are required for the initiation of DNA replication, their essential targets being the MCM2-7 proteins. We show that, in Xenopus laevis egg extracts and human cells, hyper-phosphorylation of DNA-bound Mcm4, but not phosphorylation of Mcm2, correlates with DNA replication. These phosphorylations are differentially affected by the DDK inhibitors PHA-767491 and XL413. We show that DDK-dependent MCM phosphorylation is reversed by protein phosphatase 1 (PP1) targeted to chromatin by Rif1. Loss of Rif1 increased MCM phosphorylation and the rate of replication initiation and also compromised the ability of cells to block initiation when challenged with replication inhibitors. We also provide evidence that Rif1 can mediate MCM dephosphorylation at replication forks and that the stability of dephosphorylated replisomes strongly depends on Chk1 activity. We propose that both replication initiation and replisome stability depend on MCM phosphorylation, which is maintained by a balance of DDK-dependent phosphorylation and Rif1-mediated dephosphorylation. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  7. Blue-green photoluminescence in MCM-41 mesoporous nanotubes

    CERN Document Server

    Shen, J L; Lui, Y L; Cheng, P W; Cheng, C F

    2003-01-01

    Different photoluminescence (PL) techniques have been used to study the blue-green emission from siliceous MCM-41 nanotubes. It was found that the intensity of the blue-green PL is enhanced by rapid thermal annealing (RTA). This enhancement is explained by the generation of twofold-coordinated Si centres and non-bridging oxygen hole centres, in line with the surface properties of MCM-41. On the basis of the analysis of the PL following RTA, polarized PL, and PL excitation, we suggest that the triplet-to-singlet transition of twofold-coordinated silicon centres is responsible for the blue-green PL in MCM-41 nanotubes. (letter to the editor)

  8. Lysine-Grafted MCM-41 Silica as an Antibacterial Biomaterial.

    Science.gov (United States)

    Villegas, María F; Garcia-Uriostegui, Lorena; Rodríguez, Ofelia; Izquierdo-Barba, Isabel; Salinas, Antonio J; Toriz, Guillermo; Vallet-Regí, María; Delgado, Ezequiel

    2017-09-26

    This paper proposes a facile strategy for the zwitterionization of bioceramics that is based on the direct incorporation of l-lysine amino acid via the ε-amino group onto mesoporous MCM-41 materials. Fourier transform infrared (FTIR) studies of lysine-grafted MCM-41 (MCM-LYS) simultaneously showed bands at 3080 and 1540 cm -1 and bands at 1625 and 1415 cm -1 corresponding to -NH 3+ /COO - pairs, which demonstrate the incorporation of the amino acid on the material surface keeping its zwitterionic character. Both elemental and thermogravimetric analyses showed that the amount of grafted lysine was 8 wt. % based on the bioceramic total weight. Moreover, MCM-LYS exhibited a reduction of adhesion of S. aureus and E. coli bacteria in 33% and 50%, respectively at physiological pH, as compared with pristine MCM-41. Biofilm studies onto surfaces showed that lysine functionalization elicited a reduction of the area covered by S. aureus biofilm from 42% to only 5% (88%). This research shows a simple and effective approach to chemically modify bioceramics using single amino acids that provides zwitterionic functionality, which is useful to develop new biomaterials that are able to resist bacterial adhesion.

  9. Lysine-Grafted MCM-41 Silica as an Antibacterial Biomaterial

    Directory of Open Access Journals (Sweden)

    María F. Villegas

    2017-09-01

    Full Text Available This paper proposes a facile strategy for the zwitterionization of bioceramics that is based on the direct incorporation of l-lysine amino acid via the ε-amino group onto mesoporous MCM-41 materials. Fourier transform infrared (FTIR studies of lysine-grafted MCM-41 (MCM-LYS simultaneously showed bands at 3080 and 1540 cm−1 and bands at 1625 and 1415 cm−1 corresponding to -NH3+/COO− pairs, which demonstrate the incorporation of the amino acid on the material surface keeping its zwitterionic character. Both elemental and thermogravimetric analyses showed that the amount of grafted lysine was 8 wt. % based on the bioceramic total weight. Moreover, MCM-LYS exhibited a reduction of adhesion of S. aureus and E. coli bacteria in 33% and 50%, respectively at physiological pH, as compared with pristine MCM-41. Biofilm studies onto surfaces showed that lysine functionalization elicited a reduction of the area covered by S. aureus biofilm from 42% to only 5% (88%. This research shows a simple and effective approach to chemically modify bioceramics using single amino acids that provides zwitterionic functionality, which is useful to develop new biomaterials that are able to resist bacterial adhesion.

  10. Synthesis and characterization of Co (Ni or Cu)-MCM-41 mesoporous molecular sieves with different amount of metal obtained by using microwave irradiation method

    International Nuclear Information System (INIS)

    Jiang Tingshun; Zhao Qian; Chen Kangmin; Tang Yajing; Yu Longbao; Yin Hengbo

    2008-01-01

    Co (Ni or Cu)-MCM-41 mesoporous molecular sieves with different amount of metal were synthesized by using cetyltrimethyl ammonium bromide as a template and by a novel microwave irradiation method. These samples were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and N 2 physical adsorption. The experimental results show that Co (Ni or Cu)-MCM-41 mesoporous molecular sieves were successfully synthesized. When the as-synthesized samples were calcined at 550 deg. C for 10 h, the template was effectively removed. Under microwave irradiation condition, Co-MCM-41 mesoporous molecular sieves have specific surface areas in a range of 745.7-1188.8 m 2 /g and average pore sizes in a range of 2.46-2.75 nm; Ni-MCM-41 mesoporous molecular sieves have specific surface areas in a range of 625.8-1161.3 m 2 /g and average pore sizes of ca. 2.7 nm; Cu-MCM-41 mesoporous molecular sieves have specific surface areas in a range of 601.6-1142.9 m 2 /g and average pore sizes in a range of 2.46-2.76 nm. On the other hand, with increasing the introduced metal amount, the specific surface area and pore volume of the synthesized Co (Ni or Cu)-MCM-41 mesoporous molecular sieves became small, and the mesoporous ordering of the samples became poor. Under the comparable synthesis conditions, the synthesized Co-MCM-41 mesoporous molecular sieve has a bigger specific surface area and a more uniform pore distribution as compared with the synthesized Ni-MCM-41and Cu-MCM-41 mesoporous molecular sieves

  11. Suppression of Reserve MCM Complexes Chemosensitizes to Gemcitabine and 5-Fluorouracil.

    Science.gov (United States)

    Bryant, Victoria L; Elias, Roy M; McCarthy, Susan M; Yeatman, Timothy J; Alexandrow, Mark G

    2015-09-01

    Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest forms of cancer and is very difficult to treat with conventional chemotherapeutic regimens. Gemcitabine and 5-fluorouracil are used in the management of PDAC and act by indirectly blocking replicative forks. However, these drugs are not highly effective at suppressing disease progression, indicating a need for the development of innovative therapeutic approaches. Recent studies indicate that suppression of the MCM helicase may provide a novel means to sensitize cancer cells to chemotherapeutic agents that inhibit replicative fork progression. Mammalian cells assemble more MCM complexes on DNA than are required to start S-phase. The excess MCM complexes function as backup initiation sites under conditions of replicative stress. The current study provides definitive evidence that cosuppression of the excess/backup MCM complexes sensitizes PDAC tumor lines to both gemcitabine and 5-FU, leading to increased loss of proliferative capacity compared with drugs alone. This occurs because reduced MCM levels prevent efficient recovery of DNA replication in tumor cells exposed to drug. PDAC tumor cells are more sensitive to MCM loss in the presence of gemcitabine than are nontumor, immortalized epithelial cells. Similarly, colon tumor cells are rendered less viable when cosuppression of MCM complexes occurs during exposure to the crosslinking agent oxaliplatin or topoisomerase inhibitor etoposide. These studies demonstrate that suppressing the backup complement of MCM complexes provides an effective sensitizing approach with the potential to increase the therapeutic index of drugs used in the clinical management of PDAC and other cancers. ©2015 American Association for Cancer Research.

  12. Preparation and Humidity Sensing Properties of KCl/MCM-41 Composite

    International Nuclear Information System (INIS)

    Li, Liu; Lian-Yuan, Wang; Wei, Li; Li-Ying, Kou; Zhi-Cheng, Zhong; Li-Fang, Liu

    2010-01-01

    KCl/mobil composition of matter-41 (MCM-41) composite has been synthesized via a heat-treating process and characterized by x-ray diffraction, high resolution transmission electron microscopy, and nitrogen adsorption/desorption isotherms. In contrast with pure MCM-41, KCl/MCM-41 composite exhibits improved humidity sensing properties within the relative humidity range of 11–95%. The impedance of KCl/MCM-41 composite changes by about four orders of magnitude over the whole humidity range with the response time and the recovery times are about 30 s and 35 s, respectively. Small humidity hysteresis and good stability are also observed based on our product. These results make our product a good candidate in fabricating humidity sensors with high performances and low synthetic complexity

  13. Application of as-synthesised MCM-41 and MCM-41 wrapped with reduced graphene oxide/graphene oxide in the remediation of acetaminophen and aspirin from aqueous system.

    Science.gov (United States)

    Akpotu, Samson O; Moodley, Brenda

    2018-03-01

    In this study, ASM41 (as-synthesised MCM-41), MCM-41, MCM-41 encapsulated with graphene oxide (MCM-41-GO) and reduced graphene oxide (MCM-41-G) were fabricated and utilized in the remediation of acetaminophen and aspirin from water. A surfactant template (cetyltrimethylammonium bromide) was added to ASM41 to make it more hydrophobic and its effects on the remediation of acetaminophen and aspirin from wastewater was studied. To further improve the adsorption capacity of the adsorbent, MCM-41 was encapsulated with GO and G which also aided in easy separation of the adsorbent from the aqueous solution. Comparative studies of the adsorption of acetaminophen and aspirin on all four adsorbents were investigated. Batch adsorption studies of acetaminophen and aspirin were carried out to determine the effects of pH, initial concentration, time and adsorbent dose. Adsorption mechanism was through EDA, π-π interactions, and hydrophobic effects. Data from sorption kinetics showed ASM41 had the highest q m value for aspirin (909.1 mg/g) and MCM-41-G had the highest q m value for acetaminophen (555.6 mg/g). The significant adsorption by ASM41 can be attributed to increased hydrophobicity due to the retention of the surfactant template. Thermodynamic studies revealed the adsorption process as spontaneous and exothermic. Desorption studies revealed that adsorbents could be regenerated and reused for adsorption. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. UV Damage-Induced Phosphorylation of HBO1 Triggers CRL4DDB2-Mediated Degradation To Regulate Cell Proliferation

    Science.gov (United States)

    Matsunuma, Ryoichi; Ohhata, Tatsuya; Kitagawa, Kyoko; Sakai, Satoshi; Uchida, Chiharu; Shiotani, Bunsyo; Matsumoto, Masaki; Nakayama, Keiichi I.; Ogura, Hiroyuki; Shiiya, Norihiko; Kitagawa, Masatoshi

    2015-01-01

    Histone acetyltransferase binding to ORC-1 (HBO1) is a critically important histone acetyltransferase for forming the prereplicative complex (pre-RC) at the replication origin. Pre-RC formation is completed by loading of the MCM2-7 heterohexameric complex, which functions as a helicase in DNA replication. HBO1 recruited to the replication origin by CDT1 acetylates histone H4 to relax the chromatin conformation and facilitates loading of the MCM complex onto replication origins. However, the acetylation status and mechanism of regulation of histone H3 at replication origins remain elusive. HBO1 positively regulates cell proliferation under normal cell growth conditions. Whether HBO1 regulates proliferation in response to DNA damage is poorly understood. In this study, we demonstrated that HBO1 was degraded after DNA damage to suppress cell proliferation. Ser50 and Ser53 of HBO1 were phosphorylated in an ATM/ATR DNA damage sensor-dependent manner after UV treatment. ATM/ATR-dependently phosphorylated HBO1 preferentially interacted with DDB2 and was ubiquitylated by CRL4DDB2. Replacement of endogenous HBO1 in Ser50/53Ala mutants maintained acetylation of histone H3K14 and impaired cell cycle regulation in response to UV irradiation. Our findings demonstrate that HBO1 is one of the targets in the DNA damage checkpoint. These results show that ubiquitin-dependent control of the HBO1 protein contributes to cell survival during UV irradiation. PMID:26572825

  15. Rapid synthesis of Ti-MCM-41 by microwave-assisted hydrothermal method towards photocatalytic degradation of oxytetracycline.

    Science.gov (United States)

    Chen, Hanlin; Peng, Yen-Ping; Chen, Ku-Fan; Lai, Chia-Hsiang; Lin, Yung-Chang

    2016-06-01

    This study employed microwave-assisted hydrothermal method to synthesize Ti-MCM-41, which are mesoporous materials with a high surface area and excellent photocatalytic ability. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and ultraviolet-visible spectroscopy (UV-Vis) were employed. The XRD findings showed that Ti-MCM-41 exhibited a peak at 2θ of 2.2°, which was attributed to the hexagonal MCM-41 structure. The BET (Brunauer-Emmett-Teller) results agreed with the TEM findings that Ti-MCM-41 has a pore size of about 3-5nm and a high surface area of 883m(2)/g. FTIR results illustrated the existence of Si-O-Si and Si-O-Ti bonds in Ti-MCM-41. The appearance of Ti 2p peaks in the XPS results confirmed the FTIR findings that the Ti was successfully doped into the MCM-41 structure. Zeta (ζ)-potential results indicated that the iso-electric point (IEP) of Ti-MCM-41 was at about pH3.02. In this study, the photocatalytic degradation of oxytetracycline (OTC) at different pH was investigated under Hg lamp irradiation (wavelength 365nm). The rate constant (K'obs) for OTC degradation was 0.012min(-1) at pH3. Furthermore, TOC (total organic carbon) and high resolution LC-MS (liquid chromatography-mass spectrometry) analyses were conducted to elucidate the possible intermediate products and degradation pathway for OTC. The TOC removal efficiency of OTC degradation was 87.0%, 74.4% and 50.9% at pH3, 7 and 10, respectively. LC-MS analysis results showed that the degradation products from OTC resulted from the removal of functional groups from the OTC ring. Copyright © 2016. Published by Elsevier B.V.

  16. Elimination of ketone vapors by adsorption on spherical MCM-41 and MCM-48 silicas decorated with thermally activated poly(furfuryl alcohol)

    Energy Technology Data Exchange (ETDEWEB)

    Machowski, Kamil [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków (Poland); Kuśtrowski, Piotr, E-mail: kustrows@chemia.uj.edu.pl [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków (Poland); Dudek, Barbara [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków (Poland); Michalik, Marek [Institute of Geological Sciences, Jagiellonian University, Oleandry 2a, 30-063 Kraków (Poland)

    2015-09-01

    Spherical MCM-41 and MCM-48 silicas with different arrangements of mesopores were synthesized in a water–alcohol solution of surfactant by the hard-templating method. The pore structure and morphology of the obtained materials were confirmed by powder X-ray diffraction (XRD), low-temperature adsorption of nitrogen and scanning electron microscopy (SEM). The surface of mesoporous silicas was decorated with small amounts of poly(furfuryl alcohol) (PFA), which was introduced by the precipitation polymerization and subsequently thermally activated at 523 K to form stable C=O surface species detected by FTIR spectroscopy. The adsorption capacity of the PFA/silica composites in the elimination of various ketone (acetone, methyl-ethyl ketone and methyl-isobutyl ketone) vapors was compared to the effectiveness of pristine silicas. It was found that the modification of silicas by thermally degraded PFA enhanced their adsorption capacity. This effect was attributed to the appearance of another type of surface centers (namely carbonyl groups), which beside silanols interact with ketone molecules via hydrogen bonds. DRIFT spectra showed that a ketone molecule is bonded on silanol species in its keto form, whereas on carbonyl functionalities in enol one. - Highlights: • Surface of spherical MCM-type silicas was decorated with poly(furfuryl alcohol). • Thermal degradation of deposited polymer resulted in formation of C=O species. • Carbonyl groups enhanced adsorption capacity of MCM-41 and MCM-48 silicas. • Adsorption of ketones in enol or keto forms was revealed by DRIFT measurements.

  17. Elimination of ketone vapors by adsorption on spherical MCM-41 and MCM-48 silicas decorated with thermally activated poly(furfuryl alcohol)

    International Nuclear Information System (INIS)

    Machowski, Kamil; Kuśtrowski, Piotr; Dudek, Barbara; Michalik, Marek

    2015-01-01

    Spherical MCM-41 and MCM-48 silicas with different arrangements of mesopores were synthesized in a water–alcohol solution of surfactant by the hard-templating method. The pore structure and morphology of the obtained materials were confirmed by powder X-ray diffraction (XRD), low-temperature adsorption of nitrogen and scanning electron microscopy (SEM). The surface of mesoporous silicas was decorated with small amounts of poly(furfuryl alcohol) (PFA), which was introduced by the precipitation polymerization and subsequently thermally activated at 523 K to form stable C=O surface species detected by FTIR spectroscopy. The adsorption capacity of the PFA/silica composites in the elimination of various ketone (acetone, methyl-ethyl ketone and methyl-isobutyl ketone) vapors was compared to the effectiveness of pristine silicas. It was found that the modification of silicas by thermally degraded PFA enhanced their adsorption capacity. This effect was attributed to the appearance of another type of surface centers (namely carbonyl groups), which beside silanols interact with ketone molecules via hydrogen bonds. DRIFT spectra showed that a ketone molecule is bonded on silanol species in its keto form, whereas on carbonyl functionalities in enol one. - Highlights: • Surface of spherical MCM-type silicas was decorated with poly(furfuryl alcohol). • Thermal degradation of deposited polymer resulted in formation of C=O species. • Carbonyl groups enhanced adsorption capacity of MCM-41 and MCM-48 silicas. • Adsorption of ketones in enol or keto forms was revealed by DRIFT measurements.

  18. CD117 immunoexpression in canine mast cell tumours: correlations with pathological variables and proliferation markers

    Directory of Open Access Journals (Sweden)

    Pires Maria A

    2007-08-01

    Full Text Available Abstract Background Cutaneous mast cell tumours are one of the most common neoplasms in dogs and show a highly variable biologic behaviour. Several prognosis tools have been proposed for canine mast cell tumours, including histological grading and cell proliferation markers. CD117 is a receptor tyrosine kinase thought to play a key role in human and canine mast cell neoplasms. Normal (membrane-associated and aberrant (cytoplasmic, focal or diffuse CD117 immunoexpression patterns have been identified in canine mast cell tumours. Cytoplasmic CD117 expression has been found to correlate with higher histological grade and with a worsened post-surgical prognosis. This study addresses the role of CD117 in canine mast cell tumours by studying the correlations between CD117 immunoexpression patterns, two proliferation markers (Ki67 and AgNORs histological grade, and several other pathological variables. Results Highly significant (p Conclusion These findings highlight the key role of CD117 in the biopathology of canine MCTs and confirm the relationship between aberrant CD117 expression and increased cell proliferation and higher histological grade. Further studies are needed to unravel the cellular mechanisms underlying focal and diffuse cytoplasmic CD117 staining patterns, and their respective biopathologic relevance.

  19. Non-essential MCM-related proteins mediate a response to DNA damage in the archaeon Methanococcus maripaludis.

    Science.gov (United States)

    Walters, Alison D; Chong, James P J

    2017-05-01

    The single minichromosome maintenance (MCM) protein found in most archaea has been widely studied as a simplified model for the MCM complex that forms the catalytic core of the eukaryotic replicative helicase. Organisms of the order Methanococcales are unusual in possessing multiple MCM homologues. The Methanococcus maripaludis S2 genome encodes four MCM homologues, McmA-McmD. DNA helicase assays reveal that the unwinding activity of the three MCM-like proteins is highly variable despite sequence similarities and suggests additional motifs that influence MCM function are yet to be identified. While the gene encoding McmA could not be deleted, strains harbouring individual deletions of genes encoding each of the other MCMs display phenotypes consistent with these proteins modulating DNA damage responses. M. maripaludis S2 is the first archaeon in which MCM proteins have been shown to influence the DNA damage response.

  20. Preparation and use of chemically modified MCM-41 and silica gel as selective adsorbents for Hg(II) ions

    International Nuclear Information System (INIS)

    Puanngam, Mahitti; Unob, Fuangfa

    2008-01-01

    Adsorbents for Hg(II) ion extraction were prepared using amorphous silica gel and ordered MCM-41. Grafting with 2-(3-(2-aminoethylthio)propylthio)ethanamine was used to functionalize the silica. The functionalized adsorbents were characterized by nitrogen adsorption, X-ray diffraction, 13 C MAS NMR spectroscopy and thermogravimetric analysis. The adsorption properties of the modified silica gel and MCM-41 were compared using batch method. The effect of pH, stirring time, ionic strength and foreign ions were studied. The extraction of Hg(II) ions occurred rapidly with the modified MCM-41 and the optimal pH range for the extraction by the modified materials was pH 4-7. Foreign ions, especially Cl - had some effect on the extraction efficiency of the modified silica gel and the modified MCM-41. The adsorption behavior of both adsorbents could be described by a Langmuir model at 298 K, and the maximum adsorption capacity of the modified silica gel and MCM-41 at pH 3 was 0.79 and 0.70 mmol g -1 , respectively. The modified MCM-41 showed a larger Langmuir constant than that of the modified silica gel, indicating a better ability for Hg(II) ion adsorption. The results indicate that the structure of the materials affects the adsorption behavior. These materials show a potential for the application as effective and selective adsorbents for Hg(II) removal from water

  1. synthesis, characterization and catalytic activity of the pillared molecular sieve MCM-36

    NARCIS (Netherlands)

    He, Y.; Nivarthy, G.S.; Eder, F.; Eder, F.; Seshan, Kulathuiyer; Lercher, J.A.

    1998-01-01

    MCM-36 materials were prepared by swelling the layered MCM-22 precursors with large organic molecules and then pillaring the resulting material with polymeric silica. A mesopore region with 0.25–0.3 nm thickness between the microporous layers was identified. The BET surface area obtained for MCM-36

  2. The comparison of nuclear ubiquitous casein and cyclin-dependent kinases substrate (NUCKS) with Ki67 proliferation marker expression in common skin tumors.

    Science.gov (United States)

    Zduniak, Krzysztof; Agrawal, Siddarth; Symonowicz, Krzysztof; Jurczyszyn, Kamil; Ziółkowski, Piotr

    2014-03-01

    Nuclear ubiquitous casein and cyclin-dependent kinases substrate (NUCKS) is a chromosomal protein of unknown function. Its amino acid composition and structure of its DNA binding domain resemble those of high mobility group A (HMGA) proteins which are associated with various malignancies. Since changes in expression of HMGA are considered as a marker of tumor progression, it is possible that similar changes in expression of NUCKS could be a useful tool in diagnosis of malignant skin tumors. To investigate this assumption we used specific antibodies against NUCKS for immunohistochemistry of squamous (SCC) and basal cell carcinoma (BCC) as well as keratoacanthoma (KA). We found high expression of NUCKS in nuclei of SCC and BCC cells which exceeded expression of the well-known proliferation marker Ki67. Expression of NUCKS in benign KA was much below that of malignant tumors. With the present study and based on our previous experience we would like to suggest the NUCKS protein as a novel proliferation marker for immunohistochemical evaluation of formalin-fixed and paraffin-embedded skin tumor specimens. We would like to emphasize that NUCKS abundance in malignant skin tumors is higher than that of the well-known proliferation marker Ki67, thus allowing more precise assessment of tumor proliferation potential.

  3. Catalytic Oxidation of Vanillyl Alcohol Using FeMCM-41 Nanoporous Tubular Reactor

    Science.gov (United States)

    Elamathi, P.; Kolli, Murali Krishna; Chandrasekar, G.

    Iron containing nanoporous MCM-41 (FeMCM-41) with different Si/Fe ratios of 50, 100 and 150 was synthesized by hydrothermal synthesis process. The materials obtained from hydrothermal synthesis were characterized by various physico chemical techniques such as XRD, N2 adsorption, DR UV-vis, EPR and FTIR spectroscopy. XRD analyses of FeMCM-41 materials confirmed the presence of well-ordered crystalline structure. N2 isotherm of FeMCM-41 materials showed type IV adsorption isotherm. EPR and DR UV-vis analysis of FeMCM-41 samples indicates the presence of high tetrahedral coordination at the Si/Fe ratios of 100 and 150. The catalytic performance of FeMCM-41 nano tubular reactor was tested in the liquid phase oxidation of vanillyl alcohol into vanillin using H2O2 (50wt% in water). The reaction products were analyzed by gas chromatography in DB-5 capillary column with flame ionization detector. The products were confirmed by 1H NMR, 13C NMR and LC-Mass spectroscopy. The maximum conversion of vanillyl alcohol (85%) and selectivity towards vanillin (82%) were observed using the catalyst FeMCM-41(100) in 30min at 60∘C. The influence of reaction temperature, reaction time, reactants molar ratio, Si/Fe ratio and amount of catalyst were investigated.

  4. Modified Ta/MCM-41 catalysts for enantioselective oxidation of thioanisole

    OpenAIRE

    Fadhli, Marwa; Khedher, Ilyes; Fraile, José M.

    2015-01-01

    Ta-MCM41 catalysts have been prepared by grafting of Ta(OEt)5 on MCM41, pre-calcined at three different temperatures (550, 650 and 750 °C). These solids have been modified with two chiral ligands: R-(+)-diethyl l-tartrate (DET) and R-(+)-diisopropyl l-tartrate (DIPT). The formation of the chiral tantalum species and their influence on the structure of MCM41 have been studied by several characterization techniques, such as XRD, FTIR, N2 adsorption isotherms and MAS NMR. The grafted tantalum sp...

  5. Preparation, characterization and optical properties of Lanthanum-(nanometer MCM-41) composite materials

    International Nuclear Information System (INIS)

    Zhai, Q. Z.; Wang, P.

    2008-01-01

    Nanometer MCM-41 molecular sieve was prepared under a base condition by using cetyltrimethylammonium bromide as template and tetraethyl orthosilicate as silica source by means of hydrothermal method. Lanthanum(III) was incorporated into the nanometer MCM-41 by a liquid phase grafting method. The prepared nano composite materials were characterized by means of powder X-ray diffraction, spectrophotometric analysis, Fourier transform infrared spectroscopy, low temperature nitrogen adsorption-desorption technique, solid diffuse reflectance absorption spectra and luminescence. The powder X-ray diffraction studies show that the nanometer MCM-41 molecular sieve is successfully prepared. The highly ordered meso porous two-dimensional hexagonal channel structure and framework of the support MCM-41 is retained intact in the prepared composite material La-(nanometer MCM-41). The spectrophotometric analysis indicates that lanthanum exists in the prepared nano composite materials. The Fourier transform infrared spectra indicate that the framework of the MCM-41 molecular sieve still remains in the prepared nano composite materials and some framework vibration peaks show blue shifts relative to those of the MCM-41 molecular sieve. The low temperature nitrogen adsorption-desorption indicates that the guest locales in the channel of the molecular sieve. Compared with bulk lanthanum oxide, the guest in the channel of the molecular sieve has smaller particle size and shows a significant blue shift of optical absorption band in solid diffuse reflectance absorption spectra. The observed blue shift in the solid state diffuse reflectance absorption spectra of the lanthanum-(nanometer MCM-41) sample show the obvious stereoscopic confinement effect of the channel of the host on the guest, which further indicates the successful encapsulation of the guest in the host. The La-(nanometer MCM-41) sample shows luminescence

  6. Molecular architecture of the recombinant human MCM2-7 helicase in complex with nucleotides and DNA

    DEFF Research Database (Denmark)

    Boskovic, Jasminka; Bragado-Nilsson, Elisabeth; Saligram Prabhakar, Bhargav

    2016-01-01

    DNA replication is a key biological process that involves different protein complexes whose assembly is rigorously regulated in a successive order. One of these complexes is a replicative hexameric helicase, the MCM complex, which is essential for the initiation and elongation phases of replicati...

  7. Metal Nanoparticles Supported on Al-MCM-41 via In Situ Aqueous Synthesis

    International Nuclear Information System (INIS)

    Alonso-Lemus, I.; Aguilar-Elguezabal, A.; Alvarez-Contreras, L.; Verde-Gomez, Y.

    2010-01-01

    MCM-41 have been used to custom synthesize catalysts in because of the controllable properties, such as pore size, active phase incorporation, crystal size, and morphology, among others. In this paper, a simple and versatile method for the incorporation of platinum, ruthenium, and palladium onto Al-MCM-41 mesoporous silica by direct inclusion of various precursors was studied. M/Al-MCM-41 structure, textural properties, morphology, and elemental composition were analyzed. The results obtained indicate that the Al-MCM-41 mesoporous-ordered structure was not affected by metallic particle incorporation. High-surface areas were obtained (1131 m2/g). Metallic nanoparticles dispersion on Al-MCM-41 was homogeneous for all samples and its particles sizes were between 6?nm to 20 nm. Microscopy results show round shape particles in platinum and palladium samples; however, ruthenium catalysts exhibit a spherical and rod shapes. Electrochemical testing for Pt/Al-MCM-41 showed electrocatalytic activity for H2 oxidation which indicates that these materials can be used as a catalyst in electrochemical devices.

  8. Adsorption of Pb2+ on Thiol-functionalized Mesoporous Silica, SH-MCM-48

    Science.gov (United States)

    Taba, P.; Mustafa, R. D. P.; Ramang, L. M.; Kasim, A. H.

    2018-03-01

    Modification of mesoporous silica, MCM-48, by using 3- mercaptopropyltrimethoxysilane has been successfully conducted. MCM-48 and SH-MCM-48 were characterized using XRD and FTIR. SH-MCM-48 was used as an adsorbent of Pb2+ ions from solution. A number of Pb2+ ions adsorbed were studied as the function of time, pH, and concentration. The concentration of the ions after adsorption was determined by an Atomic Absorption Spectrophotometer. The removal of the adsorbed ions from the SH-MCM-48 was also studied using several desorbing agents. The result showed that the optimum time was 20 minutes and optimum pH was 4. The adsorption of Pb(II) ion followed the pseudo-second-order with the rate constant of 0,2632 g•mg-1•min-1. Adsorption of Pb(II) ion fitted the Langmuir isotherm with the adsorption capacity of 0,1088 mmol/g. The best desorbing agent to remove the adsorbed ion from SH-MCM-48 was 0.3 M HCl solution with the desorption percentage of 58.6%.

  9. Mechanism of Archaeal MCM Helicase Recruitment to DNA Replication Origins

    Science.gov (United States)

    Samson, Rachel Y.; Abeyrathne, Priyanka D.; Bell, Stephen D.

    2015-01-01

    Summary Cellular DNA replication origins direct the recruitment of replicative helicases via the action of initiator proteins belonging to the AAA+ superfamily of ATPases. Archaea have a simplified subset of the eukaryotic DNA replication machinery proteins and possess initiators that appear ancestral to both eukaryotic Orc1 and Cdc6. We have reconstituted origin-dependent recruitment of the homohexameric archaeal MCM in vitro with purified recombinant proteins. Using this system, we reveal that archaeal Orc1-1 fulfills both Orc1 and Cdc6 functions by binding to a replication origin and directly recruiting MCM helicase. We identify the interaction interface between these proteins and reveal how ATP binding by Orc1-1 modulates recruitment of MCM. Additionally, we provide evidence that an open-ring form of the archaeal MCM homohexamer is loaded at origins. PMID:26725007

  10. Synthesis, characterization and magnetic properties of Fe/MCM-48

    International Nuclear Information System (INIS)

    Oliva, M.I; Elias, V.R; Eimer, G.A; Silvetti, S.P; Urreta, S.E

    2008-01-01

    Mesoporous silicates called MCM-48 have a structure of interconnected pores with a cubic three dimensional arrangement, with diameters ranging from 1-10nm. This kind of pore configuration has elevated surface areas (more than 1000 m 2 /g) so these molecular MCM-48 sieves are useful for supporting and encapsulating nanophases of different transition metals, metal oxides and organometallic compounds. Nanocomposites are formed with potential applications in the areas of electronics, optics, magnetism, energy storage, drug transport and catalysis. For this work MCM-48 materials were synthesized and then modified with Fe by the wet impregnation method. Two sources of Fe were used: Fe(NO 3 ) 3 .9H 2 O and FeSO 4 .7H 2 O. The silica, previously roasted at 773 K, was suspended in a large amount of aqueous solution that initially contained the amount of iron to be deposited (5%p/p) and that was agitated for a short time. The mixture was then placed in a bath at 353K without agitation for 8 hours. Finally the water was eliminated in a rotating evaporator at 333K. The powder obtained was dried in a stove at 333K for 8 hours and calcined at 773K for 4 hours. The microstructure of the resulting composites was characterized by X-ray diffraction (XRD) and ultraviolet-visible diffuse reflectance (UVvis-DR). The magnetic properties were studied as a function of the temperature following zero field cooling (ZFC) and field cooling (FC) protocols between 300K and 5K and by measuring the hysterisis curves at different temperatures in the same range. The DRX studies confirmed a MCM-48 type structure for all the matrices, consistent with the high surface areas - around 1300 m 2 /g- measured. The structure and the surface areas of the composites were affected by the addition of the metal. While the UVvis-DR and DRX analyses of the composites obtained showed that the iron subjects in the final material are similar for both sources of iron used, they have different magnetic behaviors

  11. Synthesis and physicochemical properties of Zr-MCM-41 mesoporous molecular sieves and Pt/H3PW12O40/Zr-MCM-41 catalysts

    International Nuclear Information System (INIS)

    Chen, L.F.; Wang, J.A.; Norena, L.E.; Aguilar, J.; Navarrete, J.; Salas, P.; Montoya, J.A.; Del Angel, P.

    2007-01-01

    For the first time, modifications of the surface and framework of Si-MCM-41 by depositing a heteropolyacid on the surface and by introducing foreign Zr 4+ ions into the framework are investigated. The Zr-modified Si-MCM-41 mesoporous materials (hereafter referred as WSZn, n=Si/Zr=25, 15, 8, 4) were synthesized through a surfactant-templated preparation approach, using low-cost fumed silica as the Si precursor. After impregnation with 25 wt% of H 3 PW 12 O 40 , the surface Broensted acidity of the Pt/H 3 PW 12 O 40 /WSZn catalysts was greatly enhanced by 2-10 times relative to the bare WSZn support. Two kinds of supported heteropolyacids were formed: (i) bulk-like heteropolyacid crystals with unchanged Keggin structures, and (ii) highly dispersed heteropolyacid with distorted Keggin units. The formation of various kinds of heteropolyacid structures is closely related to the interaction between the heteropolyanions and the hydroxyl groups in the host support. - Graphical abstract: Modifications of the surface and framework of Si-MCM-41 by depositing a heteropolyacid on the surface and by introducing foreign Zr 4+ ions into the framework are investigated. Broensted acidity of the Pt/H 3 PW 12 O 40 /Zr-MCM-41 catalysts was greatly enhanced by 2-10 times relative to the bare Zr-MCM-41 support

  12. 78 FR 17996 - MCM Rail Services LLC-Petition for Retroactive Exemption-In Sparrows Point, Md.

    Science.gov (United States)

    2013-03-25

    ... DEPARTMENT OF TRANSPORTATION Surface Transportation Board [Docket No. FD 35707] MCM Rail Services... regarding a petition for an operation exemption submitted by MCM Rail Services LLC (MCM) regarding 12 miles of rail line in Sparrows Point, Md. (the Line). DATES: MCM's supplemental information is due by April...

  13. Effect of template in MCM-41 on the adsorption of aniline from aqueous solution.

    Science.gov (United States)

    Yang, Xinxin; Guan, Qingxin; Li, Wei

    2011-11-01

    The effect of the surfactant template cetyltrimethylammonium bromide (CTAB) in MCM-41 on the adsorption of aniline was investigated. Various MCM-41 samples were prepared by controlling template removal using an extraction method. The samples were then used as adsorbents for the removal of aniline from aqueous solution. The results showed that the MCM-41 samples with the template partially removed (denoted as C-MCM-41) exhibited better adsorption performance than MCM-41 with the template completely removed (denoted as MCM-41). The reason for this difference may be that the C-MCM-41 samples had stronger hydrophobic properties and selectivity for aniline because of the presence of the template. The porosity and cationic sites generated by the template play an important role in the adsorption process. The optimal adsorbent with moderate template was achieved by changing the ratio of extractant; it has the potential for promising applications in the field of water pollution control. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Recycling of surfactant template in mesoporous MCM-41 synthesis

    Science.gov (United States)

    Lai, J. Y.; Twaiq, F.; Ngu, L. H.

    2017-06-01

    The recycling of surfactant template is investigated through the reuse of the surfactant template in the mesoporous MCM-41 synthesis process. In the synthesis of MCM-41, tetraethylorthosilicate (TEOS) solution in water was utilized as the silica source while hexadecyltrimethylammonium bromide (CTAB) solution in ethyl alcohol was used as a surfactant template. The synthesized gel is formed thoroughly by mixing the two solutions under acid conditions with a pH value of 0.5 for 1 hour and kept for crystallization for 48 hours. The as-synthesized MCM-41 powder is recovered by filtration while the filtrate (mother liquor) was then reused for the second synthesis cycle. The synthesis procedure was repeated till no further solid product was formed. The synthesized gel was not produced in the unifying solution in the fifth cycle of MCM-41 synthesis. The quality of the calcined MCM-41 powder produced in each synthesis cycle was evaluated by calculating the amount of MCM-41 produced and the surface area of the powder product. The result showed that 1.28, 0.37, 1.64, 1.90 and 0.037 g were obtained in the 1st, 2nd, 3rd, 4th and 5th synthesis cycle, respectively. The surface area of the powder produced was found to be 1170, 916, 728, and 508 m2/g for 1st, 2nd, 3rd and 4th respectively. The concentration of the surfactant template has reached value lower than the critical micelle concentration (CMC) and remained constant after the 4th cycle. There was no further formation of gel due to low availability in the interaction between silicate anions and surfactant cations when the amount of TEOS was fixed for every synthesis cycle.

  15. Highly reusability surface loaded metal particles magnetic catalyst microspheres (MCM-MPs) for treatment of dye-contaminated water

    International Nuclear Information System (INIS)

    Liu, Ying; Zhang, Kun; Yin, Xiaoshuang; Yang, Wenzhong; Zhu, Hongjun

    2016-01-01

    The metal-deposited magnetic catalyst microspheres (MCM-MPs) were successfully synthesized by one facile, high yield and controllable approach. Here, the bare magnetic microspheres were firstly synthesized according to the solvothermal method. Then silica shell were coated on the surface of the magnetic microspheres via sol–gel method, and subsequently with surface modifying with amino in the purpose to form SiO_2–NH_2 shell. Thus, metal particles were easily adsorbed into the SiO_2–NH_2 shell and in-situ reduced by NaBH_4 solution. All the obtained products (MCM-Cu, MCM-Ag, MCM-Pd) which were monodisperse and constitutionally stable were exhibited high magnetization and excellent catalytic activity towards dyes solution reduction. The catalytic rate ratio of MCM-Pd: MCM-Cu: MCM-Ag could be 10:3:1. Besides, some special coordination compound Cu_2(OH)_3Br had been generated in the in-situ reduced process of MCM-Cu, which produced superior cyclical stability (>20 times) than that of MCM-Ag and MCM-Pd. In all, those highly reusability and great catalytic efficiency of MCM-MPs show promising and great potential for treatment of dye-contaminated water. - Graphical abstract: Surface loaded metal particles magnetic catalyst microspheres MCM-MPs for rapid decolorizing dye-contaminated water: Synthesis, characterization and possible mechanisms. - Highlights: • A simple and high yield synthetic method for fabricate multi MCM-MPs is proposed with adequately optimize. • The highest reusability of MCM-Cu is attribute to the coordination compounds Cu_2(OH)_3Br. • MCM-MPs show excellent catalytic properties under different situations for various dyes • The catalytic mechanism of MCM-MPs is presented.

  16. Ultrasonic-assisted synthesis and magnetic studies of iron oxide/MCM-41 nanocomposite

    International Nuclear Information System (INIS)

    Ursachi, Irina; Vasile, Aurelia; Ianculescu, Adelina; Vasile, Eugeniu; Stancu, Alexandru

    2011-01-01

    Highlights: → A quick and facile route for the synthesis of iron oxide/MCM-41 nanocomposite. → Magnetic nanoparticles were stabilized inside the pores of mesoporous silica MCM-41. → The pore size of MCM-41 dictates the properties of iron oxide nanoparticles. → The procedure provides a narrow size distribution of magnetic nanoparticles. - Abstract: Iron oxide nanoparticles were stabilized within the pores of mesoporous silica MCM-41 amino-functionalized by a sonochemical method. Formation of iron oxide nanoparticles inside the mesoporous channels of amino-functionalized MCM-41 was realized by wet impregnation using iron nitrate, followed by calcinations at 550 deg. C in air. The effect of functionalization level on structural and magnetic properties of obtained nanocomposites was studied. The resulting materials were characterized by powder X-ray diffraction (XRD), high-resolution transmission electron microscopy and selected area electron diffraction (HRTEM and SAED), vibrating sample and superconducting quantum interface magnetometers (VSM and SQUID) and nitrogen adsorption-desorption isotherms measurements. The HRTEM images reveal that the most of the iron oxide nanoparticles were dispersed inside the mesopores of silica matrix and the pore diameter of the amino-functionalized MCM-41 matrix dictates the particle size of iron oxide nanoparticles. The obtained material possesses mesoporous structure and interesting magnetic properties. Saturation magnetization value of magnetic iron oxide nanopatricles stabilized in MCM-41 amino-functionalized by in situ sonochemical synthesis was 1.84 emu g -1 . An important finding is that obtained magnetic nanocomposite materials exhibit enhanced magnetic properties than those of iron oxide/MCM-41 nanocomposite obtained by conventional method. The described method is providing a rather short preparation time and a narrow size distribution of iron oxide nanoparticles.

  17. Synthesis of Co/MCM-41catalysts and characterization by XRD, EDX, DTA/TG, SEM and TEM

    International Nuclear Information System (INIS)

    Sousa, B.V.; Rodrigues, M.G.F.

    2009-01-01

    Full text: In this work, molecular sieve MCM-41 was prepared as well as the Co/MCM-41 catalyst, via humid impregnation with concentration of 5 wt.% and 10 wt.% Co/MCM- 41. The attainment of the mesoporous molecular sieve, Si-MCM-41, was confirmed by the x-ray diffractogram. It was verified that after the calcination all the bromine (Br) was removed indicating that the calcination process removed all surfactant in the mesoporous structure. XRD and EDX analyses indicated that cobalt was found in the form of Co3O2 in the Co/MCM-41 catalysts. The diffraction standards showed that the impregnation and calcination processes caused changes in the structure only for catalyst with 10 wt.% Co/MCM-41. The DTA/TG curves showed that cobalt nitrate was totally decomposed on the MCM-41. From the images of SEM, it was possible to observe that the Co/MCM-41 catalysts were composed by clusters of small crystals. The images obtained from TEM showed clearly the presence of metal cobalt particles in a well dispersed form for catalyst with 5 wt.% Co/MCM41, except for the catalyst with 10 wt.% Co/MCM41. (author)

  18. Mechanism insight of pollutant degradation and bromate inhibition by Fe-Cu-MCM-41 catalyzed ozonation.

    Science.gov (United States)

    Chen, Weirui; Li, Xukai; Tang, Yiming; Zhou, Jialu; Wu, Dan; Wu, Yin; Li, Laisheng

    2018-03-15

    A flexible catalyst, Fe-Cu-MCM-41, was employed to enhance diclofenac (DCF) mineralization and inhibit bromate formation in catalytic ozonation process. Greater TOC removal was achieved in Fe-Cu-MCM-41/O 3 process (78%) than those in Fe-MCM-41/O 3 (65%), Cu-MCM-41/O 3 (73%) and sole ozonation (42%). But it was interesting that both Cu-MCM-41/O 3 and Fe-MCM-41/O 3 achieved 93% bromate inhibition efficiency, only 71% inhibition efficiency was observed in Fe-Cu-MCM-41/O 3 . Influence of pH, TBA/NaHSO 3 and detection of by-products were conducted to explore the mechanism. By Pyridine adsorption-IR and XPS, a relationship was found among activity of catalysts, Lewis acid sites and electron transfer effect between Fe (II/III) and Cu (I/II). Fe-Cu-MCM-41 promoted ozone decomposition to generate OH, which accounted for enhanced DCF mineralization. The consumption of aqueous O 3 also suppressed the oxidative of Br - and HBrO/Br - . More HBrO/BrO - accumulated in catalytic ozonation process and less bromate generated. Bromate formation in Fe-Cu-MCM-41/O 3 process was sensitive with pH value, the acidic condition was not favor for bromate formation. Both DCF mineralization and bromate inhibition were influenced by surface reaction. Moreover, Fe-Cu-MCM-41 showed excellent catalytic performance in suppressing the accumulation of carboxylic acid, especially for oxalic acid. Nearly no oxalic acid was detected during Fe-Cu-MCM-41/O 3 process. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Highly reusability surface loaded metal particles magnetic catalyst microspheres (MCM-MPs) for treatment of dye-contaminated water

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ying; Zhang, Kun, E-mail: kun4219@njtech.edu.cn; Yin, Xiaoshuang; Yang, Wenzhong; Zhu, Hongjun

    2016-04-01

    The metal-deposited magnetic catalyst microspheres (MCM-MPs) were successfully synthesized by one facile, high yield and controllable approach. Here, the bare magnetic microspheres were firstly synthesized according to the solvothermal method. Then silica shell were coated on the surface of the magnetic microspheres via sol–gel method, and subsequently with surface modifying with amino in the purpose to form SiO{sub 2}–NH{sub 2} shell. Thus, metal particles were easily adsorbed into the SiO{sub 2}–NH{sub 2} shell and in-situ reduced by NaBH{sub 4} solution. All the obtained products (MCM-Cu, MCM-Ag, MCM-Pd) which were monodisperse and constitutionally stable were exhibited high magnetization and excellent catalytic activity towards dyes solution reduction. The catalytic rate ratio of MCM-Pd: MCM-Cu: MCM-Ag could be 10:3:1. Besides, some special coordination compound Cu{sub 2}(OH){sub 3}Br had been generated in the in-situ reduced process of MCM-Cu, which produced superior cyclical stability (>20 times) than that of MCM-Ag and MCM-Pd. In all, those highly reusability and great catalytic efficiency of MCM-MPs show promising and great potential for treatment of dye-contaminated water. - Graphical abstract: Surface loaded metal particles magnetic catalyst microspheres MCM-MPs for rapid decolorizing dye-contaminated water: Synthesis, characterization and possible mechanisms. - Highlights: • A simple and high yield synthetic method for fabricate multi MCM-MPs is proposed with adequately optimize. • The highest reusability of MCM-Cu is attribute to the coordination compounds Cu{sub 2}(OH){sub 3}Br. • MCM-MPs show excellent catalytic properties under different situations for various dyes • The catalytic mechanism of MCM-MPs is presented.

  20. NRL 12-Bit, 213 Msps ADC HSAD9 MCM Evaluation Board

    National Research Council Canada - National Science Library

    Thai, Khanh

    1999-01-01

    The MCM Evaluation Board is a 6" by 6" test fixture designed for evaluating the HSAD9 MCM, a completely self contained ADC multichip module that digitizes incoming differential analog signals to 12...

  1. Synthesis, Characterizations, and Applications of Metal-Ions Incorporated High Quality MCM-41 Catalysts

    International Nuclear Information System (INIS)

    Lim, Steven S.; Haller, Gary L.

    2013-01-01

    Various metal ions (transition and base metals) incorporated MCM-41 catalysts can be synthesized using colloidal and soluble silica with non-sodium involved process. Transition metal ion-typically V 5+ , Co 2+ , and Ni 2+ -incorporated MCM-41 catalysts were synthesized by isomorphous substitution of Si ions in the framework. Each incorporated metal ion created a single species in the silica framework, single-site solid catalyst, showing a substantial stability in reduction and catalytic activity. Radius of pore curvature effect was investigated with Co-MCM-41 by temperature programmed reduction (TPR). The size of metallic Co clusters, sub-nanometer, could be controlled by a proper reduction treatment of Co-MCM-41 having different pore size and the initial pH adjustment of the Co-MCM-41 synthesis solution. These small metallic clusters showed a high stability under a harsh reaction condition without serious migration, resulting from a direct anchoring of small metallic clusters to the partially or unreduced metal ions on the surface. After a complete reduction, partial occlusion of the metallic cluster surface by amorphous silica stabilized the particles against aggregations. As a probe reaction of particle size sensitivity, carbon single wall nanotubes (SWNT) were synthesized using Co-MCM-41. A metallic cluster stability test was performed by CO methanation using Co- and Ni-MCM-41. Methanol and methane partial oxidations were carried out with V-MCM-41, and the radius of pore curvature effect on the catalytic activity was investigated

  2. Skeletal muscle Kv7 (KCNQ) channels in myoblast differentiation and proliferation

    International Nuclear Information System (INIS)

    Roura-Ferrer, Meritxell; Sole, Laura; Martinez-Marmol, Ramon; Villalonga, Nuria; Felipe, Antonio

    2008-01-01

    Voltage-dependent K + channels (Kv) are involved in myocyte proliferation and differentiation by triggering changes in membrane potential and regulating cell volume. Since Kv7 channels may participate in these events, the purpose of this study was to investigate whether skeletal muscle Kv7.1 and Kv7.5 were involved during proliferation and myogenesis. Here we report that, while myotube formation did not regulate Kv7 channels, Kv7.5 was up-regulated during cell cycle progression. Although, Kv7.1 mRNA also increased during the G 1 -phase, pharmacological evidence mainly involves Kv7.5 in myoblast growth. Our results indicate that the cell cycle-dependent expression of Kv7.5 is involved in skeletal muscle cell proliferation

  3. Antibacterial nanocomposites based on chitosan/Co-MCM as a selective and efficient adsorbent for organic dyes.

    Science.gov (United States)

    Khan, Shahid Ali; Khan, Sher Bahadar; Kamal, Tahseen; Yasir, Muhammad; Asiri, Abdullah M

    2016-10-01

    Chitosan/cobalt-silica (Co-MCM) nanocomposites were synthesized for the purification of effluent by adding 5, 15 and 25mL of Co-MCM solution to the aqueous chitosan solution for the formation of chitosan/Co-MCM-5, chitosan/Co-MCM-15 and chitosan/Co-MCM-25, respectively. These different nanocomposites were characterized by FESEM, EDS, X-ray crystallography and IR spectrophotometer and employed for the adsorption of various dyes (methyl orange, acridine orange, indigo carmine and congo red). The respective nanocomposites showed good adsorption toward methyl orange, indigo carmine and congo red while all nanocomposites were inactive for acridine orange dye. Among the nanocomposites, chitosan/Co-MCM-15 showed the highest adsorption performance which might be due to ideal dispersion of Co-MCM inside the chitosan polymer host. Chitosan/Co-MCM-15 exhibited high adsorption for methyl orange as compared to indigo carmine. We have further checked the biological potential of chitosan/Co-MCM nanocomposites against gram positive and negative bacteria as well as multi drug resistant bacteria. The results favor the strongest bioactivities of chitosan/Co-MCM-15 against various gram positive and gram negative bacteria as well as multi drug resistant bacteria, which further suggest the ideal dispersion of Co-MCM in chitosan polymer host and is responsible for the improvement of both adsorption as well as biological performance. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Relationship between the structure of Fe-MCM-48 and its activity in catalytic ozonation for diclofenac mineralization.

    Science.gov (United States)

    Li, Xukai; Chen, Weirui; Tang, Yiming; Li, Laisheng

    2018-05-12

    Fe-MCM-48 catalyst with a three-dimensional cubic pore structure was directly synthesized via a hydrothermal method, and the mineralization efficiency of diclofenac (DCF) in the catalytic ozonation process (Fe-MCM-48/O 3 ) was assessed. X-ray diffraction (XRD), N 2 adsorption desorption, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) characterizations revealed that Fe existed in the framework of MCM-48, and Fe-MCM-48 possessed a large surface area and a highly ordered cubic mesoporous structure, which could accelerate reactants and products diffusion. Regarding mineralization efficiency, the addition of Fe-MCM-48 significantly improved total organic carbon (TOC) removal, and approximately 49.9% TOC were removed through the Fe-MCM-48/O 3 process at 60 min, which was 2.0 times higher than that in single ozonation. Due to this catalyst's superior structure, Fe-MCM-48 showed the better catalytic activity compared with Fe-MCM-41 and Fe loaded MCM-48 (Fe/MCM-48, Fe existed on the surface of MCM-48). DCF removal in the Fe-MCM-48/O 3 process was primarily based on ozone direct oxidation. The improvement of mineralization efficiency was attributed to the function of generated hydroxyl radicals (•OH), which indicated that the presence of Fe-MCM-48 accelerated ozone decomposition. Moreover, the negatively charged surface of Fe-MCM-48 and the proper pH value of the DCF solution played an essential role in OH generation. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. Analysis of the crystal structure of an active MCM hexamer.

    Science.gov (United States)

    Miller, Justin M; Arachea, Buenafe T; Epling, Leslie B; Enemark, Eric J

    2014-09-29

    In a previous Research article (Froelich et al., 2014), we suggested an MCM helicase activation mechanism, but were limited in discussing the ATPase domain because it was absent from the crystal structure. Here we present the crystal structure of a nearly full-length MCM hexamer that is helicase-active and thus has all features essential for unwinding DNA. The structure is a chimera of Sulfolobus solfataricus N-terminal domain and Pyrococcus furiosus ATPase domain. We discuss three major findings: 1) a novel conformation for the A-subdomain that could play a role in MCM regulation; 2) interaction of a universally conserved glutamine in the N-terminal Allosteric Communication Loop with the AAA+ domain helix-2-insert (h2i); and 3) a recessed binding pocket for the MCM ssDNA-binding motif influenced by the h2i. We suggest that during helicase activation, the h2i clamps down on the leading strand to facilitate strand retention and regulate ATP hydrolysis.

  6. Origin Licensing Requires ATP Binding and Hydrolysis by the MCM Replicative Helicase

    Science.gov (United States)

    Coster, Gideon; Frigola, Jordi; Beuron, Fabienne; Morris, Edward P.; Diffley, John F.X.

    2014-01-01

    Summary Loading of the six related Minichromosome Maintenance (MCM) proteins as head-to-head double hexamers during DNA replication origin licensing is crucial for ensuring once-per-cell-cycle DNA replication in eukaryotic cells. Assembly of these prereplicative complexes (pre-RCs) requires the Origin Recognition Complex (ORC), Cdc6, and Cdt1. ORC, Cdc6, and MCM are members of the AAA+ family of ATPases, and pre-RC assembly requires ATP hydrolysis. Here we show that ORC and Cdc6 mutants defective in ATP hydrolysis are competent for origin licensing. However, ATP hydrolysis by Cdc6 is required to release nonproductive licensing intermediates. We show that ATP binding stabilizes the wild-type MCM hexamer. Moreover, by analyzing MCM containing mutant subunits, we show that ATP binding and hydrolysis by MCM are required for Cdt1 release and double hexamer formation. This work alters our view of how ATP is used by licensing factors to assemble pre-RCs. PMID:25087873

  7. High acidity unilamellar zeolite MCM-56 and its pillared and delaminated derivatives.

    Science.gov (United States)

    Gil, Barbara; Makowski, Wacław; Marszalek, Bartosz; Roth, Wieslaw J; Kubu, Martin; Čejka, Jiři; Olejniczak, Zbigniew

    2014-07-21

    The unilamellar form of zeolite MWW, MCM-56, which is obtained by direct hydrothermal synthesis has been studied with regard to acidity and porosity in its original and post-synthesis modified pillared and delaminated forms. The acidity measured by FTIR was found to be only slightly lower than the highly active 3-D MWW forms, MCM-22 and MCM-49. Pivalonitrile adsorption, which is a measure of spatial openness, showed 50% accessibility vs. MCM-22/49. It highlights the potential of MCM-56 as a layered material with increased access to acid sites because it does not entail laborious post-synthesis modification. Swelling, pillaring and delamination of MCM-56 are facile but result in a reduction in the number of Brønsted acid sites (BAS) while increasing accessibility to pivalonitrile. The delamination procedure involving sonication and acidification of the highly basic mother liquor produces the most visible increase in surface area and access to all BAS. The accompanying doubling of the solid yield and the decrease in absolute number of BAS suggest significant precipitation of dissolved silica generated during swelling and sonication in high pH medium. The viability of separating surfactant covered layers upon sonication with the consequence of exposing hydrophobic hydrocarbon tails to aqueous environment is addressed.

  8. Phosphopeptide binding by Sld3 links Dbf4-dependent kinase to MCM replicative helicase activation.

    Science.gov (United States)

    Deegan, Tom D; Yeeles, Joseph Tp; Diffley, John Fx

    2016-05-02

    The initiation of eukaryotic DNA replication requires the assembly of active CMG (Cdc45-MCM-GINS) helicases at replication origins by a set of conserved and essential firing factors. This process is controlled during the cell cycle by cyclin-dependent kinase (CDK) and Dbf4-dependent kinase (DDK), and in response to DNA damage by the checkpoint kinase Rad53/Chk1. Here we show that Sld3, previously shown to be an essential CDK and Rad53 substrate, is recruited to the inactive MCM double hexamer in a DDK-dependent manner. Sld3 binds specifically to DDK-phosphorylated peptides from two MCM subunits (Mcm4, 6) and then recruits Cdc45. MCM mutants that cannot bind Sld3 or Sld3 mutants that cannot bind phospho-MCM or Cdc45 do not support replication. Moreover, phosphomimicking mutants in Mcm4 and Mcm6 bind Sld3 without DDK and facilitate DDK-independent replication. Thus, Sld3 is an essential "reader" of DDK phosphorylation, integrating signals from three distinct protein kinase pathways to coordinate DNA replication during S phase. © 2016 The Authors. Published under the terms of the CC BY 4.0 license.

  9. Homeobox A7 stimulates breast cancer cell proliferation by up-regulating estrogen receptor-alpha

    International Nuclear Information System (INIS)

    Zhang, Yu; Cheng, Jung-Chien; Huang, He-Feng; Leung, Peter C.K.

    2013-01-01

    Highlights: •HOXA7 regulates MCF7 cell proliferation. •HOXA7 up-regulates ERα expression. •HOXA7 mediates estrogen-induced MCF7 cell proliferation. -- Abstract: Breast cancer is the most common hormone-dependent malignancy in women. Homeobox (HOX) transcription factors regulate many cellular functions, including cell migration, proliferation and differentiation. The aberrant expression of HOX genes has been reported to be associated with human reproductive cancers. Estradiol (E2) and its nuclear receptors, estrogen receptor (ER)-alpha and ER-beta, are known to play critical roles in the regulation of breast cancer cell growth. However, an understanding of the potential relationship between HOXA7 and ER in breast cancer cells is limited. In this study, our results demonstrate that knockdown of HOXA7 in MCF7 cells significantly decreased cell proliferation and ERα expression. In addition, HOXA7 knockdown attenuated E2-induced cell proliferation as well as progesterone receptor (PR) expression. The stimulatory effects of E2 on cell proliferation and PR expression were abolished by co-treatment with ICI 182780, a selective ERα antagonist. In contrast, overexpression of HOXA7 significantly stimulated cell proliferation and ERα expression. Moreover, E2-induced cell proliferation, as well as PR expression, was enhanced by the overexpression of HOXA7. Neither knockdown nor overexpression of HOXA7 affected the ER-beta levels. Our results demonstrate a novel mechanistic role for HOXA7 in modulating breast cancer cell proliferation via regulation of ERα expression. This finding contributes to our understanding of the role HOXA7 plays in regulating the proliferation of ER-positive cancer cells

  10. Homeobox A7 stimulates breast cancer cell proliferation by up-regulating estrogen receptor-alpha

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yu [Department of Reproductive Endocrinology, Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou 310006 (China); Department of Obstetrics and Gynaecology, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4 (Canada); Cheng, Jung-Chien [Department of Obstetrics and Gynaecology, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4 (Canada); Huang, He-Feng, E-mail: huanghefg@hotmail.com [Department of Reproductive Endocrinology, Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou 310006 (China); Leung, Peter C.K., E-mail: peter.leung@ubc.ca [Department of Reproductive Endocrinology, Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou 310006 (China); Department of Obstetrics and Gynaecology, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4 (Canada)

    2013-11-01

    Highlights: •HOXA7 regulates MCF7 cell proliferation. •HOXA7 up-regulates ERα expression. •HOXA7 mediates estrogen-induced MCF7 cell proliferation. -- Abstract: Breast cancer is the most common hormone-dependent malignancy in women. Homeobox (HOX) transcription factors regulate many cellular functions, including cell migration, proliferation and differentiation. The aberrant expression of HOX genes has been reported to be associated with human reproductive cancers. Estradiol (E2) and its nuclear receptors, estrogen receptor (ER)-alpha and ER-beta, are known to play critical roles in the regulation of breast cancer cell growth. However, an understanding of the potential relationship between HOXA7 and ER in breast cancer cells is limited. In this study, our results demonstrate that knockdown of HOXA7 in MCF7 cells significantly decreased cell proliferation and ERα expression. In addition, HOXA7 knockdown attenuated E2-induced cell proliferation as well as progesterone receptor (PR) expression. The stimulatory effects of E2 on cell proliferation and PR expression were abolished by co-treatment with ICI 182780, a selective ERα antagonist. In contrast, overexpression of HOXA7 significantly stimulated cell proliferation and ERα expression. Moreover, E2-induced cell proliferation, as well as PR expression, was enhanced by the overexpression of HOXA7. Neither knockdown nor overexpression of HOXA7 affected the ER-beta levels. Our results demonstrate a novel mechanistic role for HOXA7 in modulating breast cancer cell proliferation via regulation of ERα expression. This finding contributes to our understanding of the role HOXA7 plays in regulating the proliferation of ER-positive cancer cells.

  11. An investigation into the Ti-grafting structure on MCM-41 and epoxidation catalysis

    DEFF Research Database (Denmark)

    Yuan, Q.C.; Hagen, A.; Roessner, F.

    2006-01-01

    The structure of titanium species grafted on a purely siliceous MCM-41 and their catalysis in the epoxidation of cyclohexene with tert-butyl hydroperoxide (TBHP) were investigated. FT-IR, XANES and UV-vis were used for the examination of the Ti-grafted MCM-41. The results indicated...... that the titanium atoms are grafted on the wall surface of the MCM-41 by four-fold coordination. The four-fold coordinated titanium species are mainly grafted by two or one -O-Si-O- bridges on the MCM-41, resulting in so-called bipodal or monopodal titanium centres in partially polymerised states. The ratio...... of monopodal to bipodal titanium increases with the increase in Ti-content. These partially polymerised titanium species considered as catalytic active centres have high activity and selectivity in the epoxidation reaction. The used Ti-grafted MCM-41 samples were regenerated by heating in nitrogen or air...

  12. Application of Mn/MCM-41 as an adsorbent to remove methyl blue from aqueous solution.

    Science.gov (United States)

    Shao, Yimin; Wang, Xi; Kang, Yuan; Shu, Yuehong; Sun, Qiangqiang; Li, Laisheng

    2014-09-01

    In this study, the application of Mn loaded MCM-41 (Mn/MCM-41) was reported as a novel adsorbent for methyl blue (MB) from aqueous solution. The mesoporous structure of Mn/MCM-41 was confirmed by XRD technique. Surface area, pore size and wall thickness were calculated from BET equation and BJH method using nitrogen sorption technique. FT-IR studies showed that Mn were loaded on the hexagonal mesoporous structures of MCM-41. It is found that the MCM-41 structure retained after loading of Mn but its surface area and pore diameter decreased due to pore blockage. Adsorption of MB from aqueous solution was investigated by Mn/MCM-41 with changing Mn content, adsorbent dosage, initial MB concentration, contact time, pH and the temperature. Under the chosen condition (25°C, 0.02 g adsorbent dosage, 6.32 pH, 50 mg L(-1) MB, 1 wt.% Mn), a high MB adsorption capacity (45.38 mg g(-1)) was achieved by Mn/MCM-41 process at 120 min, 8.6 times higher than MCM-41. The electrostatic interaction was considered to be the main mechanism for the dye adsorption. The experimental data fitted well to Freundlich and Dubinin-Radushkevich isotherms. The adsorption of MB on Mn/MCM-41 followed pseudo-second-order kinetics. Thermodynamic parameters suggested that the adsorption process is endothermic and spontaneous. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Translational and rotational dynamics of water in mesoporous silica materials: MCM-41-S and MCM-48-S

    International Nuclear Information System (INIS)

    Faraone, Antonio; Liu Li; Mou, C.-Y.; Shih, P.-C.; Copley, John R.D.; Chen, S.-H.

    2003-01-01

    We investigated the translational and rotational dynamics of water molecules in mesoporous silica materials MCM-41-S and MCM-48-S using the incoherent quasielastic neutron scattering technique. The range of wave vector transfers Q covered in the measurements was from 0.27 to 1.93 Aa -1 broad enough to detect both the translational and rotational contributions to the scattering. We used the relaxing-cage models for both translational and rotational motions which we developed earlier, to analyze the QENS spectra and investigated water dynamics in a supercooled range from 250 to 280 K. The results show a marked slowing down of both the translational and rotational relaxation times, and an increasing effect of confinement on the translational motion, as the temperature is lowered

  14. Steam stable mesoporous silica MCM-41 stabilized by trace amounts of Al.

    Science.gov (United States)

    Tompkins, Jordan T; Mokaya, Robert

    2014-02-12

    Evaluation of low and ultralow Al content (Si/Al between 50 and 412) aluminosilicate Al-MCM-41 materials synthesized via three contrasting alumination routes, namely, direct mixed-gel synthesis, post-synthesis wet grafting, and post-synthesis dry grafting, indicates that trace amounts of Al introduced via dry grafting can stabilize mesoporous silica MCM-41 to steaming at 900 °C for 4 h. It was found that trace amounts of Al (Si/Al > 400) introduced via so-called dry grafting of Al stabilize the virtually purely siliceous MCM-41 to steaming, whereas Al incorporated via other methods that involve aqueous media such as direct mixed gel synthesis or wet grafting of Al offer only limited protection at low Al content. It is particularly remarkable that a post-synthesis dry grafted Al-MCM-41 material possessing trace amounts of Al (i.e., Si/Al ratio of 412) and surface area and pore volume of 1112 m(2)/g and 1.20 cm(3)/g, respectively, retains 90% (998 m(2)/g) of the surface area and 85% (1.03 cm(3)/g) of the pore volume after exposure to steaming at 900 °C for 4 h. Under similar steam treatment conditions, the mesostructure of pure silica Si-MCM-41 is virtually destroyed and undergoes a 93% reduction in surface area (958 m(2)/g to 69 m(2)/g) and 88% decrease in pore volume (0.97 cm(3)/g to 0.12 cm(3)/g). The steam stable ultralow (i.e., trace) Al containing MCM-41 materials is found to be virtually similar to mesoporous pure silica Si-MCM-41 with hardly any detectable acidity. The improvement in steam stability arises from not only the presence of trace amounts of Al, but also from an apparent increase in the level of silica condensation that is specific to dry grafted alluminosilicate MCM-41 materials. The more highly condensed framework has fewer silanol groups and therefore is more resistant to hydrolysis under steaming conditions.

  15. Controlled drug release on amine functionalized spherical MCM-41

    International Nuclear Information System (INIS)

    Szegedi, Agnes; Popova, Margarita; Goshev, Ivan; Klébert, Szilvia; Mihály, Judit

    2012-01-01

    MCM-41 silica with spherical morphology and small particle sizes (100 nm) was synthesized and modified by post-synthesis method with different amounts of 3-aminopropyltriethoxysilane (APTES). A comparative study of the adsorption and release of a model drug, ibuprofen, was carried out. The modified and drug loaded mesoporous materials were characterized by XRD, TEM, N 2 physisorption, elemental analysis, thermal analysis and FT-IR spectroscopy. A new method was developed for the quantitative determination of amino groups in surface modified mesoporous materials by the ninhydrin reaction. Good correlation was found between the amino content of the MCM-41 materials determined by the ninhydrin method and their ibuprofen adsorption capacity. Amino modification resulted in high degree of ibuprofen loading and slow release rate in comparison to the parent non-modified MCM-41. - Graphical abstract: Determination of surface amino groups by ninhidrin method. Highlights: ► Spherical MCM-41 modified by different amounts of APTES was studied. ► Ibuprofen (IBU) adsorption and release characteristics was tested. ► The ninhydrin reaction was used for the quantitative determination of amino groups. ► Stoichiometric amount of APTES is enough for totally covering the surface with amino groups. ► Good correlation was found between the amino content and IBU adsorption capacity.

  16. The JPL telerobotic Manipulator Control and Mechanization (MCM) subsystem

    Science.gov (United States)

    Hayati, Samad; Lee, Thomas S.; Tso, Kam; Backes, Paul; Kan, Edwin; Lloyd, J.

    1989-01-01

    The Manipulator Control and Mechanization (MCM) subsystem of the telerobot system provides the real-time control of the robot manipulators in autonomous and teleoperated modes and real time input/output for a variety of sensors and actuators. Substantial hardware and software are included in this subsystem which interfaces in the hierarchy of the telerobot system with the other subsystems. The other subsystems are: run time control, task planning and reasoning, sensing and perception, and operator control subsystem. The architecture of the MCM subsystem, its capabilities, and details of various hardware and software elements are described. Important improvements in the MCM subsystem over the first version are: dual arm coordinated trajectory generation and control, addition of integrated teleoperation, shared control capability, replacement of the ultimate controllers with motor controllers, and substantial increase in real time processing capability.

  17. Hydroxyapatite/MCM-41 and SBA-15 Nano-Composites: Preparation, Characterization and Applications

    Science.gov (United States)

    Anunziata, Oscar A.; Martínez, Maria L.; Beltramone, Andrea R.

    2009-01-01

    Composites of hydroxyapatite (HaP) and highly ordered large pore mesoporous silica molecular sieves such as, Al-SBA-15 and Al-MCM-41 (denoted as SBA-15 and MCM-41, respectively) were developed, characterized by XRD, BET, FTIR, HRTEM and NMR-MAS, and applied to fluoride retention from contaminated water. The proposed procedure by a new route to prepare the HaP/SBA-15 and HaP/MCM-41, composites generates materials with aluminum only in tetrahedral coordination, according to the 27Al NMR-MAS results. Free OH- groups of HaP nanocrystals, within the hosts, allowed high capacity fluoride retention. The activity of fluoride retention using HaP/MCM-41 or HaP/SBA-15 was 1-2 orders of magnitude greater, respectively, than with pure HaP.

  18. Structure and photocatalytic activity studies of TiO2-supported over Ce-modified Al-MCM-41

    International Nuclear Information System (INIS)

    Krishna Reddy, Jakkidi; Durgakumari, Valluri; Subrahmanyam, Machiraju; Sreedhar, Bojja

    2009-01-01

    Ce-Al-MCM-41, TiO 2 /Al-MCM-41 and TiO 2 /Ce-Al-MCM-41 materials with varying contents of Ce (by impregnation) and TiO 2 loaded (by solid-state dispersion) on Al-MCM-41 support are prepared. The Ce modified and TiO 2 loaded composite systems are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectra (DRS) and X-ray photoelectron spectroscopy (XPS) techniques. The DRS and XPS of low Ce content (0.2-0.5 wt.%) modified Al-MCM-41 samples are showing more characteristic of Ce 3+ species wherein cerium in interaction with Al-MCM-41 and that of high Ce (0.8, 3.0 wt.%) content modified samples are showing the characteristic of both Ce 4+ and Ce 3+ species. A series of Ce-modified Al-MCM-41 and TiO 2 loaded composite catalysts are evaluated for photocatalytic degradation of phenol under UV irradiation. Low Ce content in Ce 3+ state on Al-MCM-41 is showing good photoactivity in comparison with high Ce content samples and pure ceria. The composite TiO 2 /Ce-Al-MCM-41 is showing enhanced degradation activity due decreased rate of electron-hole recombination on TiO 2 surface by the redox properties of cerium. The photocatalyst TiO 2 /Ce-Al-MCM-41 with an optimum of 10 wt.% TiO 2 and 0.3 wt.% Ce is showing maximum phenol degradation activity. The possible mechanism of phenol degradation on the composite photocatalyst is proposed.

  19. The proliferation marker Ki67, but not neuroendocrine expression, is an independent factor in the prediction of prognosis of primary prostate cancer patients

    Directory of Open Access Journals (Sweden)

    Pascale Mariarosa

    2016-09-01

    Full Text Available Neuroendocrine markers, which could indicate for aggressive variants of prostate cancer and Ki67 (a well-known marker in oncology for defining tumor proliferation, have already been associated with clinical outcome in prostate cancer. The aim of this study was to investigate the prognostic value of those markers in primary prostate cancer patients.

  20. Study of the influence of the silica source on the synthesis of the zeolite precursor MCM-22; Estudo da influencia da fonte de siilica na sintese do precursor zeolitico MCM-22

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, A.S.; Santos, E.R.F. dos; Leite, R.C.N.; Rodrigues, M.G.F., E-mail: antoniellybarbosa@yahoo.com.br [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Unidade Academica de Engenharia de Materiais

    2012-07-01

    Zeolite MCM-22 precursors were synthesized under hydrothermal conditions in systems with hexamethyleneimine HMI as bulking agent (driver). Synthesis parameter, such as sources of silica (aerosil® and quartz) was modified to investigate the effects on the morphology and crystallization in precursor MCM-22 zeolite. The products were characterized by X-Ray Diffraction (XRD), Energy Dispersive Spectroscopy (EDX) and Scanning Electron Microscopy (SEM). According to, the X-ray diffraction showed the same characteristic peaks of zeolite MCM-22. It was found that the parameter in this work of synthesis, silica source, affects the hydrothermal synthesis of zeolite MCM-22 precursor. This can be evidenced by the different morphologies found using the different sources of silica. (author)

  1. GINS complex protein Sld5 recruits SIK1 to activate MCM helicase during DNA replication.

    Science.gov (United States)

    Joshi, Kiranmai; Shah, Varun Jayeshkumar; Maddika, Subbareddy

    2016-12-01

    In eukaryotes, proper loading and activation of MCM helicase at chromosomal origins plays a central role in DNA replication. Activation of MCM helicase requires its association with CDC45-GINS complex, but the mechanism of how this complex activates MCM helicase is poorly understood. Here we identified SIK1 (salt-inducible kinase 1), an AMPK related protein kinase, as a molecular link that connects GINS complex with MCM helicase activity. We demonstrated that Sld5 a component of GINS complex interacts with SIK1 and recruits it to the sites of DNA replication at the onset of S phase. Depletion of SIK1 leads to defective DNA replication. Further, we showed that SIK1 phosphorylates MCM2 at five conserved residues at its N-terminus, which is essential for the activation of MCM helicase. Collectively, our results suggest SIK1 as a novel integral component of CMG replicative helicase during eukaryotic DNA replication. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Hepatic proliferation and angiogenesis markers are increased after portal deprivation in rats: a study of molecular, histological and radiological changes.

    Directory of Open Access Journals (Sweden)

    Florent Guérin

    Full Text Available To determine the pathogenesis of liver nodules, and lesions similar to obliterative portal venopathy, observed after portosystemic shunts or portal vein thrombosis in humans.We conducted an experimental study comparing portacaval shunt (PCS, total portal vein ligation (PVL, and sham (S operated rats. Each group were either sacrificed at 6 weeks (early or 6 months (late. Arterial liver perfusion was studied in vivo using CT, and histopathological changes were noted. Liver mRNA levels were quantified by RT-QPCR for markers of inflammation (Il10, Tnfa, proliferation (Il6st, Mki67, Hgf, Hnf4a, angiogenesis: (Vegfa, Vegfr 1, 2 and 3; Pgf, oxidative stress (Nos2, and 3, Hif1a, and fibrosis (Tgfb. PCS and PVL were compared to the S group.Periportal fibrosis and arterial proliferation was observed in late PCS and PVL groups. CT imaging demonstrated increased arterial liver perfusion in the PCS group. RT-QPCR showed increased inflammatory markers in PCS and PVL early groups. Tnfa and Il10 were increased in PCS and PVL late groups respectively. All proliferative markers increased in the PCS, and Hnf4a in the PVL early groups. Mki67 and Hnf4a were increased in the PCS late group. Nos3 was increased in the early and late PCS groups, and Hif1a was decreased in the PVL groups. Markers of angiogenesis were all increased in the early PCS group, and Vegfr3 and Pgf in the late PCS group. Only Vegfr3 was increased in the PVL groups. Tgf was increased in the PCS groups.Portal deprivation in rats induces a sustained increase in intrahepatic markers of inflammation, angiogenesis, proliferation, and fibrosis.

  3. [Degradation of m-Cresol with Fe-MCM-41 in Catalytic Ozonation].

    Science.gov (United States)

    Sun, Wen-jing; Wang, Ya-min; Wei, Huang-zhao; Wang, Sen; Li, Xu-ning; Li, Jing-mei; Sun, Cheng-lin; An, Lu-yang

    2015-04-01

    Fe-MCM-41 was first used for the treatment of m-cresol in catalytic ozonation. The effect of the percentage of Fe dopping mass, catalyst dosage and the natural concentration of substrate on m-cresol conversion and TOC removal were studied. The structural property of Fe-MCM-41 was characterized by X-ray diffraction, temperature-programmed reduction, Mössbauer spectra and BET of catalysts. The results showed that Fe dopping mass had a great effect on the catalytic activity of Fe-MCM-41 in catalytic ozonation and the optimal percentage of dopping mass was 4.4% (wt). The results showed that with Fe dopping mass increase, the degree of crystallinity became weaker, the crystal surface distance reduced, as well as the specific surface area, pore volume and aperture. γ-Fe2O3 was the only form staying on the surface of MCM-41, and the catalyst had good ferromagnetism and stability. Ozonation played a role of both direct oxidation and indirect oxidation in the reaction, approximately the same ratio. Under the experimental condition of the natural pH of model wastewater,using 4.4% (wt) Fe-MCM-41 as catalyst, natural concentration of m-cresol 500 mg x L(-1), catalyst dosage 0.1 g x L(-1) and reaction time 30 min, m-cresol conversion and TOC removal were 100% and 26.8%, respectively.

  4. Enhanced photocatalytic hydrogen production from an MCM-41-immobilized photosensitizer-[Fe-Fe] hydrogenase mimic dyad.

    Science.gov (United States)

    Wang, Wen; Yu, Tianjun; Zeng, Yi; Chen, Jinping; Yang, Guoqiang; Li, Yi

    2014-11-01

    A covalently linked photosensitizer-catalytic center dyad Ps-Hy, consisting of two bis(2-phenylpyridine)(2,2'-bipyridine)iridium(iii) chromophores (Ps) and a diiron hydrogenase mimic (Hy) was constructed by using click reaction. Ps-Hy was incorporated into K(+)-exchanged molecular sieve MCM-41 to form a composite (Ps-Hy@MCM-41), which has been successfully applied to the photochemical production of hydrogen. The catalytic activity of Ps-Hy@MCM-41 is ∼3-fold higher as compared with that of Ps-Hy in the absence of MCM-41. The incorporation of Ps-Hy into MCM-41 stabilizes the catalyst, and consequently, advances the photocatalysis. The present study provides a potential strategy for improving catalytic efficiency of artificial photosynthesis systems using mesoporous molecular sieves.

  5. IL-7 splicing variant IL-7δ5 induces human breast cancer cell proliferation via activation of PI3K/Akt pathway

    International Nuclear Information System (INIS)

    Pan, Deshun; Liu, Bing; Jin, Xiaobao; Zhu, Jiayong

    2012-01-01

    Highlights: ► This study confirms the role of IL-7δ5 in breast cancer cell proliferation. ► IL-7δ5 promotes breast cancer cell proliferation and cell cycle progression. ► IL-7δ5 promotes cell proliferation via activation of PI3K/Akt pathway. -- Abstract: Various tumor cells express interleukin 7 (IL-7) and IL-7 variants. IL-7 has been confirmed to stimulate solid tumor cell proliferation. However, the effect of IL-7 variants on tumor cell proliferation remains unclear. In this study, we evaluated the role of IL-7δ5 (an IL-7 variant lacking exon 5) on proliferation and cell cycle progression of human MDA-MB-231 and MCF-7 breast cancer cells. The results showed that IL-7δ5 promoted cell proliferation and cell cycle progression from G1 phase to G2/M phase, associated with upregulation of cyclin D1 expression and the downregulation of p27 kip1 expression. Mechanistically, we found that IL-7δ5 induced the activation of Akt. Inhibition of PI3K/Akt pathway by LY294002 reversed the proliferation and cell cycle progression of MDA-MB-231 and MCF-7 cells induced by IL-7δ5. In conclusion, our findings demonstrate that IL-7δ5 variant induces human breast cancer cell proliferation and cell cycle progression via activation of PI3K/Akt pathway. Thus, IL-7δ5 may be a potential target for human breast cancer therapeutics intervention.

  6. Controlled drug release on amine functionalized spherical MCM-41

    Energy Technology Data Exchange (ETDEWEB)

    Szegedi, Agnes, E-mail: szegedi@chemres.hu [Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1025 Budapest, Pusztaszeri ut 59-67 (Hungary); Popova, Margarita; Goshev, Ivan [Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Sofia (Bulgaria); Klebert, Szilvia [Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1025 Budapest, Pusztaszeri ut 59-67 (Hungary); Mihaly, Judit [Institute of Molecular Pharmacology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1025 Budapest, Pusztaszeri ut 59-67 (Hungary)

    2012-10-15

    MCM-41 silica with spherical morphology and small particle sizes (100 nm) was synthesized and modified by post-synthesis method with different amounts of 3-aminopropyltriethoxysilane (APTES). A comparative study of the adsorption and release of a model drug, ibuprofen, was carried out. The modified and drug loaded mesoporous materials were characterized by XRD, TEM, N{sub 2} physisorption, elemental analysis, thermal analysis and FT-IR spectroscopy. A new method was developed for the quantitative determination of amino groups in surface modified mesoporous materials by the ninhydrin reaction. Good correlation was found between the amino content of the MCM-41 materials determined by the ninhydrin method and their ibuprofen adsorption capacity. Amino modification resulted in high degree of ibuprofen loading and slow release rate in comparison to the parent non-modified MCM-41. - Graphical abstract: Determination of surface amino groups by ninhidrin method. Highlights: Black-Right-Pointing-Pointer Spherical MCM-41 modified by different amounts of APTES was studied. Black-Right-Pointing-Pointer Ibuprofen (IBU) adsorption and release characteristics was tested. Black-Right-Pointing-Pointer The ninhydrin reaction was used for the quantitative determination of amino groups. Black-Right-Pointing-Pointer Stoichiometric amount of APTES is enough for totally covering the surface with amino groups. Black-Right-Pointing-Pointer Good correlation was found between the amino content and IBU adsorption capacity.

  7. Selective Catalytic Reduction of NO with NH3 Over V-MCM-41 Catalyst.

    Science.gov (United States)

    Kwon, Woo Hyun; Park, Sung Hoon; Kim, Ji Man; Park, Su Bin; Jung, Sang-Chul; Kim, Sang Chai; Jeon, Jong-Ki; Park, Young-Kwon

    2016-02-01

    V-MCM-41, a mesoporous catalyst doped with V2O5, was applied for the first time to the removal of atmospheric NO. The quantity of V2O5 added was 10 wt% and 30 wt%. The characteristics of the synthesized catalysts were examined using XRD, N2 soprtion, and NH3-TPD. With increasing quantity of V2O5 added, specific surface area decreased and pore size increased. When the quantity of V2O5 was 10 wt%, the MCM-41 structure was retained, whereas considerable collapse of mesoporous structure was observed when 30 wt% V2O5 was added. The examination of acid characteristics using NH3-TPD showed that 30 wt% V-MCM-41 had the higher NH3 adsorption ability, implying that it would exhibit high activity for NH3 SCR reaction. In the NO removal experiments, 30 wt% V-MCM-41 showed much higher NO removal efficiency than 10 wt% V-MCM-41, which was attributed to its high NH3 adsorption ability.

  8. Synthesis of cerium oxide catalysts supported on MCM-41 molecular sieve; Sintese de catalisadores de oxido de cerio suportados na peneira molecular MCM-41

    Energy Technology Data Exchange (ETDEWEB)

    Souza, E.L.S.; Barros, T.R.B.; Sousa, B.V. de, E-mail: emylle.souza@gmail.com [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Unidade Academica de Engenharia Quimica

    2016-07-01

    Porous materials have been widely studied as catalysts and catalyst support. The MCM-41 structure is the one that has been most studied because of its application possibilities in chemical processes. This work aimed to obtain and characterize cerium oxide catalysts supported on MCM-41 molecular sieve. The molecular sieve was synthesized by the conventional method with the following molar composition: 1 SiO2: 0.30 CTABr: NH3 11: 144 H2O. Then, 25% w/w cerium was incorporated into the MCM-41 using the wet impregnation process and the material obtained was activated by calcination. From the XRD patterns was confirmed the structure of the molecular sieve, and were identified the cerium oxide phases in its structure. The textural catalysts characteristics were investigated by isotherms of N2 adsorption/desorption (BET method). (author)

  9. Synthesis, characterization, and catalytic properties of stable mesoporous molecular sieve MCM-41 prepared from zeolite mordenite

    International Nuclear Information System (INIS)

    Wang Shan; Dou Tao; Li Yuping; Zhang Ying; Li Xiaofeng; Yan Zichun

    2004-01-01

    Mesoporous molecular sieves (denoted as M-MCM-41) with ordered hexagonal structure have been successfully synthesized from the assembly of precursors from preformed zeolite Mordenite with CTAB surfactant micelle in alkaline media. The samples were characterized by XRD, N 2 adsorption, IR and DTG. The materials exhibit highly hydrothermal stability, as compared with conventional MCM-41. Characterization results indicate that the mesoporous walls of M-MCM-41 contain the secondary building units similar to those in microporous crystal of zeolite Mordenite. In catalytic dealkylation of C10 + aromatic hydrocarbon, M-MCM-41 shows higher activities in comparison with Mordenite and MCM-41, which would be ascribed to the combination of advantages of both MCM-41 (large pores) and Mordenite (strong acidity). Furthermore, this synthesis strategy could be used as a new general method for the preparation of hydrothermally stable mesoporous aluminosilicate materials under alkaline conditions

  10. Performance assessment of MCM-48 ceramic composite membrane by separation of AlCl3 from aqueous solution.

    Science.gov (United States)

    Kumar Basumatary, Ashim; Kumar Ghoshal, Aloke; Pugazhenthi, G

    2016-12-01

    Three dimensional ordered mesoporous MCM-48 membrane was fabricated on a circular shaped ceramic support by in-situ hydrothermal method. The synthesized MCM-48 powder and MCM-48 ceramic composite membrane were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA) and field emission scanning electron microscopy (FESEM). The porosity and pore size of the composite membrane are reduced considerably by the deposition of MCM-48 on the support. The formation of MCM-48 is verified by the XRD analysis. Three stepwise mechanisms for surfactant removal are observed by TGA analysis. FESEM images clearly signify the deposition of MCM-48 on the ceramic support. The pure water flux of the support and MCM-48 composite membrane is found to be 3.63×10 -6 and 4.18×10 -8 m 3 /m 2 skPa, respectively. The above prepared MCM-48 ceramic composite membrane is employed for the removal of AlCl 3 from aqueous solution and the highest rejection of 81% is obtained at an applied pressure of 276kPa with salt concentration of 250ppm. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Tailoring MCM-41 mesoporous silica particles through modified sol-gel process for gas separation

    Science.gov (United States)

    Sang, Wong Yean; Ching, Oh Pei

    2017-10-01

    Mobil Composition of Matter-41 (MCM-41) is recognized as a potential filler to enhance permeability of mixed matrix membrane (MMM). However, the required loading for available micron-sized MCM-41 was considerably high in order to achieve desired separation performance. In this work, reduced-size MCM-41 was synthesized to minimize filler loading, improve surface modification and enhance polymer-filler compatibility during membrane fabrication. The effect of reaction condition, stirring rate and type of post-synthesis washing solution used on particle diameter of resultant MCM-41 were investigated. It was found that MCM-41 produced at room temperature condition yield particles with smaller diameter, higher specific surface area and enhanced mesopore structure. Increase of stirring rate up to 500 rpm during synthesis also reduced the particle diameter. In addition, replacing water with methanol as the post-synthesis washing solution to remove bromide ions from the precipitate was able to further reduce the particle size by inhibiting polycondensation reaction.

  12. Enhancement in visible light photocatalytic activity by embedding Cu nanoparticles over CuS/MCM-41 nanocomposite

    Science.gov (United States)

    Sohrabnezhad, Sh.; Karamzadeh, M.

    2017-07-01

    This article indicate the biogenic synthesis of copper nanoparticles (Cu NPs) using the borage flowers extract of Borago officinalis over CuS/MCM-41 nanocomposite (NC). No external reducing was utilized in the developed method. The CuS-MCM-41 NC was used as stabilizing agent. The synthesis of CuS nanostructure in MCM-41 material has been realized by hydrothermal method. Their physiochemical properties have been characterized by X-ray diffraction, transmission electron microscopy (TEM), UV-Visible diffuse reflectance spectroscopy, and Fourier transform infrared spectroscopy. On the basis of TEM images, a layer of Cu NPs has been located over CuS/MCM-41 NC with average diameter of 60-80 nm. The results revealed the spherical nature of the prepared Cu NPs with diameter less than 10 nm. The DR spectra of Cu NPs in MCM-41 and CuS-MCM-41 NCs showed surface plasmon resonance bands at 570 and 500-600 nm, respectively. The photocatalytic activity was evaluated under visible light irradiation using the photocatalytic degradation of methylene blue (MB) as a model reaction. The prepared Cu/CuS/MCM-41 nanocomposite microspheres showed higher photodegradation ability for MB than CuS/MCM-41. The degradation of MB achieved up to 80% after 60 min and the nanocomposite could be recycled and reused.

  13. Spectral studies on the interaction of acetylacetone with aluminum-containing MCM-41 mesoporous materials

    International Nuclear Information System (INIS)

    Zanjanchi, M.A.; Vaziri, M.

    2008-01-01

    Diffuse reflectance spectroscopy (DRS) was used to study the interaction of acetylacetone (acac) with the mesoporous aluminum-containing MCM-41 materials. A room temperature synthesis method was used for preparation of purely siliceous MCM-41 and for aluminum-containing MCM-41 materials. Samples with Si/Al ratios of 50, 20, 10 and 5 were synthesized. The synthesized mesoporous materials possess highly ordered structure and high surface area as evidenced from X-ray diffraction and nitrogen physisorption measurements, respectively. The treatment of the as-synthesized aluminum-containing MCM-41 samples with acac shows a distinct band at ∼290 nm. This band is assigned to six coordinated aluminum atoms in the structure which is produced by diffusion of acac molecules through surfactant micelles and their interaction with aluminum atoms. The 290-nm band disappears upon several successive washing of the sample with ethanol. The treatment of the calcined aluminum-containing MCM-41 sample with acac produces the same 290-nm band where its intensity increases with the aluminum content of the sample. The intensity of this band is reduced upon successive ethanol washing, but remains nearly constant after three times washing. This irremovable aluminum species can be assigned to framework aluminum. The measured acidity for our aluminum-containing MCM-41 samples correlates linearly with the intensity of 290-nm band for the ethanol treated samples. This supports the idea that the Bronsted acidity in aluminum-modified MCM-41 samples is a function of the amount of tetrahedral framework aluminum in the structure

  14. Endogenous MCM7 microRNA cluster as a novel platform to multiplex small interfering and nucleolar RNAs for combinational HIV-1 gene therapy.

    Science.gov (United States)

    Chung, Janet; Zhang, Jane; Li, Haitang; Ouellet, Dominique L; DiGiusto, David L; Rossi, John J

    2012-11-01

    Combinational therapy with small RNA inhibitory agents against multiple viral targets allows efficient inhibition of viral production by controlling gene expression at critical time points. Here we explore combinations of different classes of therapeutic anti-HIV-1 RNAs expressed from within the context of an intronic MCM7 (minichromosome maintenance complex component-7) platform that naturally harbors 3 microRNAs (miRNAs). We replaced the endogenous miRNAs with anti-HIV small RNAs, including small interfering RNAs (siRNAs) targeting HIV-1 tat and rev messages that function to induce post-transcriptional gene silencing by the RNA interference pathway, a nucleolar-localizing RNA ribozyme that targets the conserved U5 region of HIV-1 transcripts for degradation, and finally nucleolar trans-activation response (TAR) and Rev-binding element (RBE) RNA decoys designed to sequester HIV-1 Tat and Rev proteins inside the nucleolus. We demonstrate the versatility of the MCM7 platform in expressing and efficiently processing the siRNAs as miRNA mimics along with nucleolar small RNAs. Furthermore, three of the combinatorial constructs tested potently suppressed viral replication during a 1-month HIV challenge, with greater than 5-log inhibition compared with untransduced, HIV-1-infected CEM T lymphocytes. One of the most effective constructs contains an anti-HIV siRNA combined with a nucleolar-localizing U5 ribozyme and TAR decoy. This represents the first efficacious example of combining Drosha-processed siRNAs with small nucleolar ribonucleoprotein (snoRNP)-processed nucleolar RNA chimeras from a single intron platform for effective inhibition of viral replication. Moreover, we demonstrated enrichment/selection for cells expressing levels of the antiviral RNAs that provide optimal inhibition under the selective pressure of HIV. The combinations of si/snoRNAs represent a new paradigm for combinatorial RNA-based gene therapy applications.

  15. Photocatalytic Properties of Nb/MCM-41 Molecular Sieves: Effect of the Synthesis Conditions

    Directory of Open Access Journals (Sweden)

    Caterine Daza Gomez

    2015-08-01

    Full Text Available The effect of synthesis conditions and niobium incorporation levels on the photocatalytic properties of Nb/MCM-41 molecular sieves was assessed. Niobium pentoxide supported on MCM-41 mesoporous silica was obtained using two methods: sol-gel and incipient impregnation, in each case also varying the percentage of niobium incorporation. The synthesized Nb-MCM-41 ceramic powders were characterized using the spectroscopic techniques of infrared spectroscopy (IR, Raman spectroscopy, X-ray diffraction (XRD, and transmission electron microscopy (TEM. The photodegradation capacity of the powders was studied using the organic molecule, methylene blue. The effect of both the method of synthesis and the percentage of niobium present in the sample on the photodegradation action of the solids was determined. The mesoporous Nb-MCM-41 that produced the greatest photodegradation response was obtained using the sol-gel method and 20% niobium incorporation.

  16. Δ9-Tetrahydrocannabinol enhances MCF-7 cell proliferation via cannabinoid receptor-independent signaling

    International Nuclear Information System (INIS)

    Takeda, Shuso; Yamaori, Satoshi; Motoya, Erina; Matsunaga, Tamihide; Kimura, Toshiyuki; Yamamoto, Ikuo; Watanabe, Kazuhito

    2008-01-01

    We recently reported that Δ 9 -tetrahydrocannabinol (Δ 9 -THC) has the ability to stimulate the proliferation of human breast carcinoma MCF-7 cells. However, the mechanism of action remains to be clarified. The present study focused on the relationship between receptor expression and the effects of Δ 9 -THC on cell proliferation. RT-PCR analysis demonstrated that there was no detectable expression of CB receptors in MCF-7 cells. In accordance with this, no effects of cannabinoid 1/2 (CB1/2) receptor antagonists and pertussis toxin on cell proliferation were observed. Although MCF-7 cell proliferation is suggested to be suppressed by Δ 9 -THC in the presence of CB receptors, it was revealed that Δ 9 -THC could exert upregulation of living cells in the absence of the receptors. Interestingly, Δ 9 -THC upregulated human epithelial growth factor receptor type 2 (HER2) expression, which is known to be a predictive factor of human breast cancer and is able to stimulate cancer cells as well as MCF-7 cells. Actinomycin D-treatment interfered with the upregulation of HER2 and cell proliferation by cannabinoid. Taken together, these studies suggest that, in the absence of CB receptors, Δ 9 -THC can stimulate the proliferation of MCF-7 cells by modulating, at least in part, HER2 transcription

  17. Catalytic steam reforming of tar derived from steam gasification of sunflower stalk over ethylene glycol assisting prepared Ni/MCM-41

    International Nuclear Information System (INIS)

    Karnjanakom, Surachai; Guan, Guoqing; Asep, Bayu; Du, Xiao; Hao, Xiaogang; Samart, Chanatip; Abudula, Abuliti

    2015-01-01

    Highlights: • Ni/MCM-41 was prepared by EG-assisted co-impregnation method. • EG-assisted co-impregnation method resulted in Ni particles well dispersed on MCM-41. • Ni/MCM-41-EG catalyst had high catalytic activity for tar reforming. • The highest H 2 gas yield was obtained when using 20 wt.% Ni/MCM-41-EG. • The catalysts were reused up to 5 cycles without any serious deactivation. - Abstract: Ethylene glycol (EG) assisted impregnation of nickel catalyst on MCM-41 (Ni/MCM-41-EG) was performed and applied for steam reforming of tar derived from biomass. The catalyst was characterized by SEM–EDX, BET, XRD, and TPR. It is found that smaller nickel particles were well dispersed on MCM-41 and better catalytic activity was shown for the Ni/MCM-41-EG when compared with the catalyst of Ni/MCM-41 prepared by using the conventional impregnation method. H 2 yield increased approximately 8% when using 20 wt.% Ni/MCM-41-EG instead of 20 wt.% Ni/MCM-41 for the steam reforming of tar derived from sunflower stalk. The catalyst reusability was also tested up to five cycles, and no obvious activity reduction was observed. It indicates that EG assisted impregnation method is a good way to prepare metal loaded porous catalyst with high catalytic activity, high loading amount and long-term stability for the tar reforming

  18. Selective catalytic reduction of NOx in lean-burn engine exhaust over a Pt/V/MCM-41 catalyst

    International Nuclear Information System (INIS)

    Jeon, Jong Yeol; Kim, Hee Young; Woo, Seong Ihl

    2003-01-01

    The activities of Pt supported on various metal-substituted MCM-41 (V-, Ti-, Fe-, Al-, Ga-, La-, Co-, Mo-, Ce-, and Zr-MCM-41) and V-impregnated MCM-41 were investigated for the reduction of NO by C 3 H 6 . Among these catalysts, Pt supported on V-impregnated MCM-41 showed the best activity. The maximum conversion of NO into N 2 +N 2 O over this Pt/V/MCM-41 catalyst (Pt=1wt.%, V=3.8wt.%) was 73%, and this maximum conversion was sustained over a temperature range of 70C from 270 to 340C. The high activity of Pt/V/MCM-41 over a broad temperature range resulted from two additional reactions besides the reaction occurring on usual supported Pt, the reaction of NO with surface carbonaceous materials, and the reaction of NO occurring on support V-impregnated MCM-41. The former additional reaction showed an oscillation characteristic, a phenomenon in which the concentrations of parts of reactant and product gases oscillate continuously. At low temperature, some water vapor injected into the reactant gas mixture promoted the reaction occurring on usual supported Pt, whereas at high temperature, it suppressed the additional reaction related to carbonaceous materials. Five-hundred parts per million of SO 2 added to the reactant gas mixture only slightly decreased the NO conversion of Pt/V/MCM-41

  19. Bimetallic iron and cobalt incorporated MFI/MCM-41 composite and its catalytic properties

    International Nuclear Information System (INIS)

    Li, Baoshan; Xu, Junqing; Li, Xiao; Liu, Jianjun; Zuo, Shengli; Pan, Zhiyun; Wu, Ziyu

    2012-01-01

    Graphical abstract: The formation of FeCo-MFI/MCM-41 composite is based on two steps, the first step of synthesizing the MFI-type proto-zeolite unites under hydrothermal conditions. The second step of assembling these zeolite fragment together new silica and heteroatom source on the CTAB surfactant micelle to synthesize the mesoporous product with hexagonal structure. Highlights: ► Bimetallic iron and cobalt incorporated MFI/MCM-41 composite was prepared using templating method. ► FeCo-MFI/MCM-41 composite simultaneously possessed two kinds of meso- and micro-porous structures. ► Iron and cobalt ions incorporated into the silica framework with tetrahedral coordination. -- Abstract: The MFI/MCM-41 composite material with bimetallic Fe and Co incorporation was prepared using templating method via a two-step hydrothermal crystallization procedure. The obtained products were characterized by a series of techniques including powder X-ray diffraction, N 2 sorption, transmission electron microscopy, scanning electron microscope, H 2 temperature programmed reduction, thermal analyses, and X-ray absorption fine structure spectroscopy of the Fe and Co K-edge. The catalytic properties of the products were investigated by residual oil hydrocracking reactions. Characterization results showed that the FeCo-MFI/MCM-41 composite simultaneously possessed two kinds of stable meso- and micro-porous structures. Iron and cobalt ions were incorporated into the silicon framework, which was confirmed by H 2 temperature programmed reduction and X-ray absorption fine structure spectroscopy. This composite presented excellent activities in hydrocracking of residual oil, which was superior to the pure materials of silicate-1/MCM-41.

  20. Preparation and controlled release of mesoporous MCM-41/propranolol hydrochloride composite drug.

    Science.gov (United States)

    Zhai, Qing-Zhou

    2013-01-01

    This article used MCM-41 as a carrier for the assembly of propranolol hydrochloride by the impregnation method. By means of chemical analysis, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy and low-temperature N(2) adsorption-desorption at 77 K, the characterization was made for the prepared materials. The propranolol hydrochloride guest assembly capacity was 316.20 ± 0.31 mg/g (drug/MCM-41). Powder XRD test results indicated that during the process of incorporation, the frameworks of the MCM-41 were not destroyed and the crystalline degrees of the host-guest nanocomposite materials prepared still remained highly ordered. Characterization by SEM and TEM showed that the composite material presented spherical particle and the average particle size of composite material was 186 nm. FT-IR spectra showed that the MCM-41 framework existed well in the (MCM-41)-propranolol hydrochloride composite. Low-temperature nitrogen adsorption-desorption results at 77 K showed that the guest partially occupied the channels of the molecular sieves. Results of the release of the prepared composite drug in simulated body fluid indicated that the drug can release up to 32 h and its maximum released amount was 99.20 ± 0.11%. In the simulated gastric juice release pattern of drug, the maximum time for the drug release was discovered to be 6 h and the maximum cumulative released amount of propranolol hydrochloride was 45.13 ± 0.23%. The drug sustained-release time was 10 h in simulated intestinal fluid and the maximum cumulative released amount was 62.05 ± 0.13%. The prepared MCM-41 is a well-controlled drug delivery carrier.

  1. Probing the porosity of cocrystallized MCM-49/ZSM-35 zeolites by hyperpolarized 129Xe NMR.

    Science.gov (United States)

    Liu, Yong; Zhang, Weiping; Xie, Sujuan; Xu, Longya; Han, Xiuwen; Bao, Xinhe

    2008-01-31

    One- and two-dimensional 129Xe NMR spectroscopy has been employed to study the porosity of cocrystallized MCM-49/ZSM-35 zeolites under the continuous flow of hyperpolarized xenon gas. It is found by variable-temperature experiments that Xe atoms can be adsorbed in different domains of MCM-49/ZSM-35 cocrystallized zeolites and the mechanically mixed counterparts. The exchange of Xe atoms in different types of pores is very fast at ambient temperatures. Even at very low temperature two-dimensional exchange spectra (EXSY) show that Xe atoms still undergo much faster exchange between MCM-49 and ZSM-35 analogues in the cocrystallized zeolites than in the mechanical mixture. This demonstrates that the MCM-49 and ZSM-35 analogues in cocrystallized zeolites may be stacked much closer than in the physical mixture, and some parts of intergrowth may be formed due to the partially similar basic structure of MCM-49 and ZSM-35.

  2. Effects of surface acidities of MCM-41 modified with MoO3 on adsorptive desulfurization of gasoline

    International Nuclear Information System (INIS)

    Shao Xinchao; Zhang Xiaotong; Yu Wenguang; Wu Yuye; Qin Yucai; Sun Zhaolin; Song Lijuan

    2012-01-01

    Highlights: ► The MoO 3 -MCM-41 samples prepared by spontaneous monolayer dispersion and impregnation with a different MoO 3 filling have been studied. ► The relative concentration of hydroxyl groups present on before and after containing MoO 3 samples was monitored by in situ FTIR to speculate the bonding style of MoO 3 and MCM-41. ► The surface acidities of the MoO 3 -MCM-41 adsorbents were investigated systematically and correlated with the desulfurization performance. - Abstract: A series of MCM-41 samples containing molybdenum oxide as active species in the mesoporous channels loaded by spontaneous monolayer dispersion (SMD) and impregnation (IM) have been prepared and characterized using XRD, N 2 adsorption–desorption analysis, Fourier transform infrared spectroscopy (FTIR) and intelligent gravimetric analyzer (IGA). The relative number of hydroxy on the adsorbents was investigated by in situ FTIR. Surface acidities of the adsorbents were studied by infrared spectroscopy of adsorbed pyridine and correlated with reactivity for adsorptive desulfurization. The IGA technique was employed to investigate adsorption behavior of thiophene and benzene on the adsorbents at 303 K. It is shown that MoO 3 can be highly dispersed up to 0.2 g g −1 in the MCM-41 channels by the SMD strategy with the ordered mesoporous structure of the MoMM samples remaining intact. The ordered mesostructure of MCM-41 is, however, destroyed at higher MoO 3 contents of 0.26 and 0.32 g g −1 with particle sizes of 1.2 nm and 3.6 nm, respectively, observed. For the MoMI(0.2) sample prepared by the IM method, the aggregation of the MoO 3 particles takes place with a particle size of 6.5 nm obtained. The results are also revealed that the dispersion extent of the MoO 3 species is related to the abundant surface hydroxy of MCM-41. The host species and guest species undergo solid-state reaction to form Si-O-Mo bonds in the mixtures which enhance both the Lewis acid and Brönsted acid of

  3. Effect of Co Mo/HSO3-functionalized MCM-41 over heavy oil

    International Nuclear Information System (INIS)

    Schacht, P.; Ramirez G, M.; Ramirez, S.; Aguilar P, J.; Norena F, L.; Abu, I.

    2010-01-01

    The potential of Co-Mo metals supported on functionalized MCM-41 as catalyst to hydrodesulfurization of heavy oil has been explored in this work. The MCM-41 functionalized sample was synthesized according to method previously reported into the support by simultaneous impregnation. The catalyst was characterized by specific surface area and X-ray diffraction. The pore channel of MCM-41 was confirmed by transmission electronic microscopy and infra red spectroscopy. Catalytic activity tests were carried out using heavy oil from Gulf of Mexico. The API gravity was increased from 12.5 to 20.2, the kinematics viscosity was decreased from 18,700 to 110 c St at 298 K, the contents of asphaltene and sulfur were also reduced. (Author)

  4. Alcohols react with MCM-41 at room temperature and chemically modify mesoporous silica.

    Science.gov (United States)

    Björklund, Sebastian; Kocherbitov, Vitaly

    2017-08-30

    Mesoporous silica has received much attention due to its well-defined structural order, high surface area, and tunable pore diameter. To successfully employ mesoporous silica for nanotechnology applications it is important to consider how it is influenced by solvent molecules due to the fact that most preparation procedures involve treatment in various solvents. In the present work we contribute to this important topic with new results on how MCM-41 is affected by a simple treatment in alcohol at room temperature. The effects of alcohol treatment are characterized by TGA, FTIR, and sorption calorimetry. The results are clear and show that treatment of MCM-41 in methanol, ethanol, propanol, butanol, pentanol, or octanol at room temperature introduces alkoxy groups that are covalently bound to the silica surface. It is shown that alcohol treated MCM-41 becomes more hydrophobic and that this effect is sequentially more prominent going from methanol to octanol. Chemical formation of alkoxy groups onto MCM-41 occurs both for calcined and hydroxylated MCM-41 and the alkoxy groups are hydrolytically unstable and can be replaced by silanol groups after exposure to water. The results are highly relevant for mesoporous silica applications that involve contact or treatment in protic solvents, which is very common.

  5. Characterization of mesoporous VOx/MCM-41 composite materials obtained via post-synthesis impregnation

    International Nuclear Information System (INIS)

    Bukallah, Saeed B.; Bumajdad, Ali; Khalil, Kamal M.S.; Zaki, Mohamed I.

    2010-01-01

    Spherical-particle MCM-41 was synthesized at room temperature, and, then, impregnated with aqueous solutions of NH 4 VO 3 to produce variously loaded VO x /MCM-41 composite materials. Bulk and surface properties of the materials thus produced were characterized by means of X-ray powder diffractometry (XRD), infrared spectroscopy (FTIR), N 2 sorptiometry and X-ray photoelectron spectroscopy (XPS). Results obtained indicated that subsequent calcination at 550 deg. C (for 2 h) of the blank and impregnated MCM-41 particles, results in materials assuming the same bulk structure of MCM-41, and exposing uniformly mesporous, high area surfaces (P w = 2.0-2.3 nm; 974-829 m 2 /g), except for the material obtained at 20 wt%-V 2 O 5 that was shown to suffer a considerable loss on surface area (down to 503 m 2 /g). XPS results implied that the immobilization of the VO x species occurs via interaction with surface OH/H 2 O groups of MCM-41, leading to the formation of vanadate (VO 3 - ) surface species, as well as minor V-O-Si and V 2 O 5 -like species. However, in all cases, the vanadium sites remained pentavalent and exposed on the surface.

  6. Synthesis and characterization of MCM-41-supported nano zirconia catalysts

    Directory of Open Access Journals (Sweden)

    Mohamed S. Abdel Salam

    2015-03-01

    Full Text Available Series of MCM-41 supported sulfated Zirconia (SZ catalysts with different loadings (2.5–7.5% wt. were prepared using direct impregnation method. The acquired solid catalysts were characterized structurally and chemically using X-RD, HRTEM, BET, FT-IR, Raman spectroscopy and TPD analysis. The acidity of the solid catalysts was investigated through cumene cracking and isopropanol dehydration at different temperatures. As the SZ loading increases, the surface acidity of the mesoporous catalysts was enhanced, this was reflected by the higher catalytic activity toward cumene cracking and isopropanol dehydration.

  7. Steam-assisted crystallization of TPA+-exchanged MCM-41 type mesoporous materials with thick pore walls

    International Nuclear Information System (INIS)

    Chen, Hong Li; Zhang, Kun; Wang, Yi Meng

    2012-01-01

    Highlights: ► Mesoporous Ti-containing silica with thicker pore walls was synthesized. ► Ion-exchange and steam-assisted crystallization led to MCM-41/MFI composite. ► The introduction of Ti inhibited the formation of separated MFI particles. ► Lower temperature favored retaining mesoporous characteristics and morphology. -- Abstract: Hierarchical MCM-41/MFI composites were synthesized through ion-exchange of as-made MCM-41 type mesoporous materials with tetrapropylammonium bromide and subsequent steam-assisted recrystallization. The obtained samples were characterized by powder X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis, FT-IR, 1 H– 13 C CP/MAS and nitrogen adsorption–desorption. The XRD patterns show that the MCM-41/MFI composite possesses both ordered MCM-41 phase and zeolite MFI phase. SEM and TEM images indicate that the recrystallized materials retained the mesoporous characteristics and the morphology of as-made mesoporous materials without the formation of bulky zeolite, quite different from the mechanical mixture of MCM-41 and MFI structured zeolite. Among others, lower recrystallization temperature and the introduction of the titanium to the parent materials are beneficial to preserve the mesoporous structure during the recrystallization process.

  8. Effect of amine functionalization of spherical MCM-41 and SBA-15 on controlled drug release

    International Nuclear Information System (INIS)

    Szegedi, A.; Popova, M.; Goshev, I.; Mihaly, J.

    2011-01-01

    MCM-41 and SBA-15 silica materials with spherical morphology and different particle sizes were synthesized and modified by post-synthesis method with 3-aminopropyltriethoxysilane (APTES). A comparative study of the adsorption and release of a model drug, ibuprofen, were carried out. The modified and drug loaded mesoporous materials were characterized by XRD, TEM, N 2 physisorption, thermal analysis, elemental analysis and FT-IR spectroscopy. Surface modification with amino groups resulted in high degree of ibuprofen loading and slow rate of release for MCM-41, whereas it was the opposite for SBA-15. The adsorbed drug content and the delivery rate can be predetermined by the choice of mesoporous material with the appropriate structural characteristics and surface functionality. -- Graphical Abstract: Ibuprofen delivery from the parent and amino-modified spherical MCM-41 materials with 100 nm (small) and 500 nm (large) particle sizes. Display Omitted Highlights: → Spherical type MCM-41 and SBA-15 with different particle sizes were modified by APTES. → Adsorption and release rate of ibuprofen were compared. → High degree of ibuprofen loading, slow release rate for MCM-41, the opposite for SBA-15. → MCM-41 with 100 nm particles was more stable and showed slower release rate

  9. MCM-41 impregnated with A zeolite precursor: Synthesis, characterization and tetracycline antibiotics removal from aqueous solution.

    Science.gov (United States)

    Liu, Minmin; Hou, Li-An; Yu, Shuili; Xi, Beidou; Zhao, Ying; Xia, Xunfeng

    2013-05-01

    In this paper, the MCM-41 has been modified by impregnation with zeolite A to prepare a kind of new adsorbent. The adsorption of TC from aqueous solutions onto modified MCM-41 has been studied. It was discovered that the adsorption capability of zeolite A modified MCM-41 (A-MCM-41) increased dramatically after modification. The modified MCM-41 was characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption, Fourier Transform Infrared (FTIR) analysis, Transmission electron microscopy (TEM) images, and 29 Si and 27 Al Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR) spectra. The modified MCM-41 structure was still retained after impregnated with zeolite A but the surface area and pore diameter decreased due to pore blockage. The adsorption of TC on modified MCM-41 was discussed regarding various parameters such as pH, initial TC concentration, and the reaction time. The pH effects on TC adsorption indicated that the adsorbents had better adsorption performances in acidic and neutral conditions. The adsorption isotherms were fitted well by the Langmuir model. The adsorption kinetics was well described by both pseudo-second order equation and the intra-particle diffusion model. The adsorption behavior in a fixed-bed column system followed Thomas model. The adsorption behavior of TC was the chemical adsorption with an ion exchange process and electrostatic adsorption.

  10. FT-IR studies on the acidity of gallium-substituted mesoporous MCM-41 silica

    International Nuclear Information System (INIS)

    Turnes Palomino, Gemma; Jose Cuart Pascual, Juan; Rodriguez Delgado, Montserrat; Bernardo Parra, Jose; Otero Arean, Carlos

    2004-01-01

    Gallium-containing mesoporous MCM-41 silica was synthesized at a nominal Si:Ga ratio of 16:1. Synthesis was carried out from a parent gel containing no cations other than NH 4 + and cetyltrimethylammonium (template), so that following thermolysis of the template agent and ammonium ions the protonic form, H-GaMCM-41, was obtained. Powder X-ray diffraction showed the characteristic pattern of MCM-41-type materials, and nitrogen adsorption at 77 K lead to a value of 535 m 2 g -1 for the specific (BET) surface area. Infrared spectroscopy of carbon monoxide adsorbed at 77 K, and of pyridine and lutidine adsorbed at room temperature, showed the presence in H-GaMCM-41 of both Broensted and Lewis acid sites. Broensted acidity, assigned to structural Si(OH)Ga groups, was most distinctively proved by protonation of both pyridine and lutidine. Lewis acidity (coordinatively unsaturated Ga 3+ ions) showed up by formation of the characteristic Lewis-type adducts with both CO and pyridine

  11. Fe_3O_4@B-MCM-41: A new magnetically recoverable nanostructured catalyst for the synthesis of polyhydroquinolines

    International Nuclear Information System (INIS)

    Abdollahi-Alibeik, Mohammad; Rezaeipoor-Anari, Ali

    2016-01-01

    Boron modified MCM-41 with magnetite core (Fe_3O_4@B-MCM-41) as a new magnetically recoverable heterogeneous catalyst was prepared and characterized by SEM, TEM, BET, XRD, VSM and FT-IR techniques. The catalytic activity of Fe_3O_4@B-MCM-41 was investigated in the four-component reaction of aldehyde, dimedone, active methylene compounds and ammonium acetate for the synthesis of polyhydroquinolines. According to optimization and characterization results the catalyst with Si:B:Fe_3O_4 mole composition of 40:4:1 has the best activity. The catalyst could be recovered easily by external magnet and has excellent reusability many times without significant decrease of activity. - Highlights: • Core–shell Fe_3O_4@MCM-41 nanoparticles modified by boron (Fe_3O_4@B-MCM-41). • Fe_3O_4@B-MCM-41 as reusable catalyst for the synthesis of polyhydroquinolines. • Characterization of Fe_3O_4@B-MCM-41 using SEM, TEM, BET, XRD and FT-IR techniques.

  12. Efeito do cromo nas propriedades catalíticas da MCM-41 The effect of chromium on the catalytic properties of MCM-41

    Directory of Open Access Journals (Sweden)

    Alcineia Conceição Oliveira

    2005-02-01

    Full Text Available The effect of chromium on the catalytic properties of MCM-41 was evaluated in order to develop new catalysts for the trimethylbenzene transalkylation with benzene to produce ethylbenzene, a high-value aromatic in the industry. It was found that chromium decreases the specific surface area but increases the acidity, turning MCM-41 into an active and selective catalyst for ethylbenzene and toluene production. The coke produced on the catalyst is hydrogenated and mainly located outside the pores and thus can be easily removed. The catalyst is more active and selective than mordenite, a commercial catalyst, and thus more promising for commercial applications.

  13. Comparative evaluation of three proliferation markers, Ki-67, TOP2A, and RacGAP1, in bronchopulmonary neuroendocrine neoplasms: Issues and prospects

    Science.gov (United States)

    Neubauer, Elisa; Wirtz, Ralph M.; Kaemmerer, Daniel; Athelogou, Maria; Schmidt, Lydia; Sänger, Jörg; Lupp, Amelie

    2016-01-01

    The classification of bronchopulmonary neuroendocrine neoplasms (BP-NEN) into four tumor entities (typical carcinoids (TC), atypical carcinoids (AC), small cell lung cancers (SCLC), large cell neuroendocrine lung carcinomas (LCNEC)) is difficult to perform accurately, but important for prognostic statements and therapeutic management decisions. In this regard, we compared the expression of three proliferation markers, Ki-67, Topoisomerase II alpha (TOP2A), and RacGAP1, in a series of tumor samples from 104 BP-NEN patients (24 TC, 21 AC, 52 SCLC, 7 LCNEC) using different evaluation methods (immunohistochemistry (IHC): Average evaluation, Hotspot evaluation, digital image analysis; RT-qPCR). The results indicated that all three markers had increased protein and mRNA expression with poorer differentiation and correlated well with each other, as well as with grading, staging, and poor survival. Compared with Ki-67 and TOP2A, RacGAP1 allowed for a clearer prognostic statement. The cut-off limits obtained for Ki-67-Average (IHC) were TC-AC 1.5, AC-SCLC 19, and AC-LCNEC 23.5. The Hotspot evaluation generated equal to higher, the digital image analysis generally lower between-entity cut-off limits. All three markers enabled a clear-cut differentiation between the BP-NEN entities, and all methods evaluated were suitable for marker assessment. However, to define optimal cut-off limits, the Ki-67 evaluation methods should be standardized. RacGAP1 appeared to be a new marker with great potential. PMID:27259241

  14. Mesoporous CeTiSiMCM-48 as novel photocatalyst for degradation of organic compounds

    International Nuclear Information System (INIS)

    Mureseanu, Mihaela; Parvulescu, Viorica; Radu, Teodora; Filip, Mihaela; Carja, Gabriela

    2015-01-01

    This work presents novel photocatalysts containing Ti and/or Ce embedded in the mesoporous silica framework (TiSiMCM-48, CeSiMCM-48 and CeTiSiMCM-48) that were prepared via a facile sol–gel process in the presence of ionic structure directing agents. The structural properties of the obtained materials were analyzed by X-ray diffraction (XRD), nitrogen adsorption-desorption, scanning and transmission electron microscopy (SEM, TEM), EDAX analysis, X-ray photoelectron microscopy (XPS), ultraviolet–visible diffuse reflectance spectroscopy (UV–vis DRS) and Fourier transformation infrared spectroscopy (FT-IR). The results indicated that Ce and Ti were highly dispersed or incorporated into the framework of the cubic SiMCM-48, with an enhanced light-trapping effect both in the UV and Vis regions. When applied to the photocatalytic degradation of phenol, the best results were obtained for the bimetallic hybrid. The best activity of CeTiSiMCM-48 photocatalyst was ascribed to improved electron–hole pair separation efficiency and formation of more reactive oxygen species due to the presence of Ce 4+ /Ce 3+ . The mesoporous support increases the dispersability of the photoactive Ti 4+ or Ce 4+ /Ce 3+ species on the catalyst surface and the accessibility of the substrate to the active sites. Furthermore, the catalysts can be easily recovered and reused for four cycles without significant loss of activity. - Highlights: • Novel photocatalysts containing Ti and/or Ce embedded in the mesoporous MCM-48 silica. • Ce 4+ /Ce 3+ improved electron–hole pair separation and reactivity of oxygen species. • The mesoporous support increases the dispersability of the photoactive species. • The photocatalyst was highly active and stable for phenol degradation under UV irradiation. • TiCeSiMCM-48 can be recycled up to four cycles without significant loss of activity

  15. Synthesis of cerium oxide catalysts supported on MCM-41 molecular sieve

    International Nuclear Information System (INIS)

    Souza, E.L.S.; Barros, T.R.B.; Sousa, B.V. de

    2016-01-01

    Porous materials have been widely studied as catalysts and catalyst support. The MCM-41 structure is the one that has been most studied because of its application possibilities in chemical processes. This work aimed to obtain and characterize cerium oxide catalysts supported on MCM-41 molecular sieve. The molecular sieve was synthesized by the conventional method with the following molar composition: 1 SiO2: 0.30 CTABr: NH3 11: 144 H2O. Then, 25% w/w cerium was incorporated into the MCM-41 using the wet impregnation process and the material obtained was activated by calcination. From the XRD patterns was confirmed the structure of the molecular sieve, and were identified the cerium oxide phases in its structure. The textural catalysts characteristics were investigated by isotherms of N2 adsorption/desorption (BET method). (author)

  16. Ibuprofen in mesopores of Mobil Crystalline Material 41 (MCM-41): a deeper understanding.

    Science.gov (United States)

    Skorupska, Ewa; Jeziorna, Agata; Paluch, Piotr; Potrzebowski, Marek J

    2014-05-05

    In this work, we compared two methods (incipient wetness and melting) for the encapsulation of ibuprofen in the pores of Mobil Crystalline Material 41 (MCM-41) through NMR (nuclear magnetic resonance) spectroscopy. (1)H NMR spectra were recorded under very fast MAS (sample spinning 60 kHz) conditions in both 1D and 2D mode (NOESY sequence). We also performed (13)C cross-polarization magic angle spinning (CP/MAS) experiments, (13)C single pulse experiments (SPE), and (1)H-(13)C HSQC HR/MAS (heteronuclear single quantum coherence high resolution) HR/MAS correlations. Evaluation of the encapsulation methods included an analysis of the filling factor of the drug into the pores. The stability of Ibu/MCM in an environment of ethanol or water vapor was tested. Our study showed that melting a mixture of Ibu and MCM is a much more efficient method of confining the drug in the pores compared to incipient wetness. The optimal experiments for the former method achieved a filling factor of approximately 60%. We concluded that the major limitation to the applicability of the incipient wetness method (filling factor ca. 20%) is the high affinity of solvent (typically ethanol) for MCM-41. We found that even ethanol vapor can remove Ibu from the pores. When a sample of Ibu/MCM was stored for a few hours in a closed vessel with ethanol vapor, Ibu was transported from the pores to the outer walls of MCM. We observed a similar phenomenon with water vapor, although this process is slower compared to the analogous procedure using ethanol. Our study clearly demonstrates that existing methods used to encapsulate drugs in mesoporous silica nanoparticles (MSNs) require reevaluation.

  17. Development of the MCM-D technique for pixel detector modules

    International Nuclear Information System (INIS)

    Grah, C.

    2005-03-01

    This thesis treats a copper--polymer based thin film technology, the MCM-D technique and its application when building hybrid pixel detector modules. The ATLAS experiment at the LHC will be equipped with a pixel detector system. The basic mechanical units of the pixel detector are multi chip modules. The main components of these modules are: 16 electronic chips, a controller chip and a large sensor tile, featuring more than 46000 sensor cells. MCM-D is a superior technique to build the necessary signal bus system and the power distribution system directly on the active sensor tile. In collaboration with the Fraunhofer Institute for Reliability and Microintegration, IZM, the thin film process is reviewed and enhanced. The multi layer system was designed and optimized for the interconnection system as well as for the 46000 pixel contacts. Laboratory measurements on prototypes prove that complex routing schemes for geometrically optimized single chips are suitable and have negligible influence on the front--end chips performance. A full scale MCM-D module has been built and it is shown that the technology is suitable to build pixel detector modules. Further tests include the investigation of the impact of hadronic irradiation on the thin film layers. Single chip assemblies have been operated in a test beam environment and the feasibility of the optimization of the sensors could be shown. A review on the potential as well as the perspective for the MCM-D technique in future experiments is given

  18. SYNTHESIS OF MCM-41 NANOMATERIAL FROM ALGERIAN ...

    African Journals Online (AJOL)

    T. Ali-Dahmane

    1 mai 2017 ... Journal of Fundamental and Applied Sciences is licensed under a Creative Commons Attribution-NonCommercial 4.0. International License. Libraries Resource Directory. We are listed under Research Associations category. SYNTHESIS OF MCM-41 NANOMATERIAL FROM ALGERIAN BENTONITE:.

  19. Adsorption of heavy metals on amine-functionalized MCM-48

    Science.gov (United States)

    Taba, P.; Budi, P.; Puspitasari, A. Y.

    2017-04-01

    The ordered mesoporous silica with cubic structure, MCM-48 was synthesized by post-synthesis under basic media using colloidal silica, cetyltrimethylammonium bromide, and Triton X-100. The modified material, NH2-MCM-48 was prepared using 3-aminopropyl trimetoxysilane (3-APTMS). X-ray diffraction and FT-IR were used to characterize the samples. The modified material was utilized for adsorption of Cu2+and Mn2+ from aqueous solution. Parameters used for studying the adsorption process were pH, time of contact, and the initial concentrations of Cu2+ and Mn2+ ions. Desorption of ions from the adsorbent was also studied using several desorbing agents. The pseudo-second order was found to be the kinetic order for the metals adsorption. The adsorption of Cu2+ and Mn2+ on NH2-MCM-48 was fixed by the Langmuir model better than the Freundlich model with the capacity of 0.52 and 0.80 mmol g-1 for Cu2+ and Mn2+, respectively. The best desorbing agents for removing the adsorbed Cu2+ and Mn2+ from the adsorbent were 1 M HNO3 and 1 M HC1, respectively.

  20. Mechanical Integrity Issues at MCM-Cs for High Reliability Applications

    International Nuclear Information System (INIS)

    Morgenstern, H.A.; Tarbutton, T.J.; Becka, G.A.; Uribe, F.; Monroe, S.; Burchett, S.

    1998-01-01

    During the qualification of a new high reliability low-temperature cofired ceramic (LTCC) multichip module (MCM), two issues relating to the electrical and mechanical integrity of the LTCC network were encountered while performing qualification testing. One was electrical opens after aging tests that were caused by cracks in the solder joints. The other was fracturing of the LTCC networks during mechanical testing. Through failure analysis, computer modeling, bend testing, and test samples, changes were identified. Upon implementation of all these changes, the modules passed testing, and the MCM was placed into production

  1. Synthesis and catalytic performance of ZSM-5/MCM-41 composite molecular sieve from palygorskite

    Science.gov (United States)

    Jiang, Jinlong; Wu, Mei; Yang, Yong; Duanmu, Chuansong; Chen, Jing; Gu, Xu

    2017-10-01

    ZSM-5/MCM-41 composite molecular sieve has been hydrothermally synthesized through a two-step crystallization process using palygorskite (PAL) as silicon and aluminum source. The products were characterized by various means and their catalytic properties for acetalization of cyclohexanone and esterification of acetic acid and n-butanol were also investigated. In the first step ZSM-5 zeolite could be formed from the acid-treated PAL after hydrothermal treatment using tetrapropylammonium bromide as template. XRD patterns, N2 adsorption and desorption data, and TEM images show that the composite obtained in the secondary step had a well-ordered mesoporous MCM-41 phase and a microporous ZSM-5 zeolite phase. Compared with ZSM-5, ZSM-5/MCM-41 composite possessed more total acid amount, weak acid sites and large pore structure due to the formation of MCM-41 and exhibited higher catalytic activity for the acetalization and esterification reaction.

  2. Efeito do cromo nas propriedades catalíticas da MCM-41

    OpenAIRE

    Oliveira,Alcineia Conceição; Rangel,Maria do Carmo; Fierro,José Luís Garcia; Reyes,Patrício; Oportus,Marcelo

    2005-01-01

    The effect of chromium on the catalytic properties of MCM-41 was evaluated in order to develop new catalysts for the trimethylbenzene transalkylation with benzene to produce ethylbenzene, a high-value aromatic in the industry. It was found that chromium decreases the specific surface area but increases the acidity, turning MCM-41 into an active and selective catalyst for ethylbenzene and toluene production. The coke produced on the catalyst is hydrogenated and mainly located outside the pores...

  3. FACTORES QUE AFECTAN LA TEXTURA Y ESTRUCTURA DE Ti(R-MCM-41 FACTORES QUE AFECTAN LA TEXTURA Y ESTRUCTURA DE Ti(R-MCM-41

    Directory of Open Access Journals (Sweden)

    J. Ramírez Solís

    2012-02-01

    Full Text Available Se ha estudiado el efecto que tienen el método de remoción del surfactante y el contenido de titanio sobre la estructura y propiedades texturales de los materiales mesoporosos Ti-MCM-41. Los sólidos sintetizados fueron caracterizados por fisisorción de N2, fluorescencia de rayos X (FRX, difracción de rayos X (DRX, microscopía electrónica de alta resolución (HREM, espectroscopía FT-Raman y de reflectancia difusa UV-vis. (DRS. Entre los dos métodos de remoción del surfactante estudiados, la aplicación de un disolvente polar (solución de H2SO4 0.05 M en etanol resultó ser más efectivo para remover el surfactante y disminuir la destrucción del material mesoporoso durante la calcinación. Las muestras tratadas con este método presentaron un mayor orden en el arreglo hexagonal de los poros (HREM, DRX y áreas superficiales más grandes. El efecto del aumento del contenido de TiO2 en los sólidos sintetizados se traduce en una disminución significativa de la intensidad del pico característico de MCM-41 (2Q = 2.2-2.5o y de las características texturales (SBET, volumen de poros, lo que indica que durante la síntesis no es posible incorporar más de 10 mol. % de TiO2 al MCM-41.Studied was the effect surfactant removal and titanium content have on the structure and textural properties of Ti-MCM-41 mesoporous materials. The synthesized solids were characterized by N2 adsorption, X-ray fluorescence (FRX, X-ray diffraction (DRX, electronic microscopy of high resolution(HREM, and FT-Raman and UV-vis diffuse reflectance spectroscopy (DRS. Between the two methods of surfactant removal studied, the application of a polar solvent (solution of 0.05 M H2SO4 in ethanol was to be more effective in removing the surfactant and diminishing the destruction of mesoporous material during calcination. The samples treated by this method showed a more ordered hexagonal pore arrangement (HREM, XRD and larger surface area. The effect of an increase in TiO2

  4. Preparation of H-mordenite/MCM-48 composite and its catalytic performance in the alkylation of toluene with tert-butanol

    Science.gov (United States)

    Zhou, Zhiwei; Cheng, Fuling; Qin, Juan; Yu, Pengcheng; Xu, Lin; Gu, Zhiqiang; Liu, Xiaoqin; Wu, Wenliang

    2017-09-01

    A series of HM/MCM-48 samples with different SiO2/Al2O3 molar ratio were prepared by sol-gel method. The prepared catalysts were characterized by XRD, N2 adsorption-desorption, NH3-TPD, FT-IR, SEM, and TEM techniques, and their catalytic performance was investigated in alkylation of toluene with tert-butanol. The adsorption capacity and the acid sites amount of HM/MCM-48-4 sample prepared by growing MCM-48 on the surface of HM zeolite are much higher than that of their mechanical mixture (HM/MCM-48(4) sample) due to its biporous structure; it shows higher catalytic performance than other HM/MCM-48 samples. The influence of reaction conditions on the catalytic performance of HM/MCM-48-4 zeolite was discussed. Toluene conversion of 41.4% and p-tert-butyltoluene selectivity of 73.5% were obtained at the weight ratio of toluene to HM/MCM-48-4 of 5, reaction temperature of 453 K, reaction time of 5 h and the molar ratio of toluene to tert-butanol of 0.5.

  5. Proliferating cell nuclear antigen (PCNA): a new marker to study human colonic cell proliferation.

    OpenAIRE

    Kubben, F J; Peeters-Haesevoets, A; Engels, L G; Baeten, C G; Schutte, B; Arends, J W; Stockbrügger, R W; Blijham, G H

    1994-01-01

    Immunohistochemistry of the S phase related proliferating cell nuclear antigen (PCNA) was studied as an alternative to ex-vivo bromodeoxyuridine (BrdU) immunohistochemistry for assessment of human colonic cell proliferation. From 16 subjects without colonic disease biopsy specimens were collected from five different sites along the colorectum and processed for BrdU and PCNA immunohistochemistry. The mean proliferation index of PCNA was significantly higher at 133% of the value obtained with B...

  6. Effect of Co Mo/HSO{sub 3}-functionalized MCM-41 over heavy oil

    Energy Technology Data Exchange (ETDEWEB)

    Schacht, P.; Ramirez G, M.; Ramirez, S. [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas No. 152, 07730 Mexico D. F. (Mexico); Aguilar P, J.; Norena F, L. [Universidad Autonoma Metropolitana, Unidad Azcapotzalco, Av. San Pablo No. 180, 02200 Mexico D. F. (Mexico); Abu, I., E-mail: pschacha@imp.m [University of Calgary, Department of Chemical and Petroleum Engineering, 2500 University Drive NW, Calgary, Alberta T2N 1N4 (Canada)

    2010-07-01

    The potential of Co-Mo metals supported on functionalized MCM-41 as catalyst to hydrodesulfurization of heavy oil has been explored in this work. The MCM-41 functionalized sample was synthesized according to method previously reported into the support by simultaneous impregnation. The catalyst was characterized by specific surface area and X-ray diffraction. The pore channel of MCM-41 was confirmed by transmission electronic microscopy and infra red spectroscopy. Catalytic activity tests were carried out using heavy oil from Gulf of Mexico. The API gravity was increased from 12.5 to 20.2, the kinematics viscosity was decreased from 18,700 to 110 c St at 298 K, the contents of asphaltene and sulfur were also reduced. (Author)

  7. Data on clinical significance of GAS2 in colorectal cancer cells

    Directory of Open Access Journals (Sweden)

    Chun-Chao Chang

    2016-09-01

    Full Text Available The growth arrest-specific 2 (GAS2 was cloned and found to be upregulated in the feces of recurrent CRC patients. This overexpressed GAS2 induced different patterns of gene expressions in CRC cells. Briefly, one cell proliferation marker, Ki-67 antigen (Ki-67, was upregulated in the cells with overexpressed GAS2, “Correlation between proliferation markers: PCNA, Ki-67, MCM-2 and antiapoptotic protein Bcl-2 in colorectal cancer” [1]. Whereas, the expression of another cell proliferation marker, proliferating cell nuclear antigen (PCNA, changed insignificantly [1]. In addition, the mRNA level of one cyclin involving in both cell cycle G1/S and G2/M transitions was also not affected by GAS2 overexpression, “Cdc20 and Cks direct the spindle checkpoint-independent destruction of cyclin A” [2]. The experimental design and procedures in this article can be helpful for understanding the molecular significance of GAS2 in SW480 and SW620 CRC cells.

  8. Preparation and spectroscopic studies of PbS/nanoMCM-41 nanocomposite

    Directory of Open Access Journals (Sweden)

    A. Pourahmad

    2014-11-01

    Full Text Available The present work describes the preparation and characterization of nanosized PbS particles inside the mesopore channels of nanoMCM-41 silicate molecular sieves. The encapsulation of the lead sulfide was carried out at room temperature by ion-exchange method. Diffuse reflectance ultraviolet–visible spectroscopic studies showed a significant shift in the absorption band for the entrapped metal sulfide as compared to corresponding bulk sulfide. Thus, confirming the quantum confinement of the incorporated nanoparticles in nanoMCM-41.

  9. Cell proliferation markers in the transplanted canine transmissible venereal tumor

    Directory of Open Access Journals (Sweden)

    F.G.A. Santos

    2011-12-01

    Full Text Available Adult male mongrel dogs were subcutaneously transplanted with the canine transmissible venereal tumor (TVT on the hypogastric region. Twelve specimens of tumors were collected, half during the proliferative phase and the other half during the regressive phase. Fragments of the tumor were fixed in 10% buffered formalin and routinely processed for light microscopy. Sections of 4µm were stained by Schorr or AgNOR or either immunostained for MIB1 (Ki67. Schorr stain, AgNOR and MIB1 showed an increased proliferative activity through mitotic index, nuclear argyrophilic protein stain and cycling tumoral cells in the growing tumors, respectively. All of the three cell proliferation markers were able to distinguish the TVT in both evolution phases. MIB1 monoclonal antibody was the best in the morphologic evaluation of growth and regression of TVT. This resulted in higher values than AgNORs counting and mitotic index. MIB1 immunostaining was the most effective parameter of the proliferative activity of TVT. However, a significant correlation has been detected only between mitosis counting and AgNORs.

  10. Proliferation marker pKi-67 affects the cell cycle in a self-regulated manner.

    Science.gov (United States)

    Schmidt, Mirko H H; Broll, Rainer; Bruch, Hans-Peter; Duchrow, Michael

    2002-01-01

    The proliferation marker pKi-67 is commonly used in research and pathology to detect proliferating cells. In a previous work, we found the protein to be associated with regulators of the cell cycle, controlling S-phase progression, as well as entry into and exit from mitosis. Here we investigate whether pKi-67 has a regulative effect on the cell cycle itself. For that purpose we cloned four fragments of pKi-67, together representing nearly the whole protein, and an N-terminal pKi-67 antisense oligonucleotide into a tetracycline inducible gene expression system. The sense fragments were C-terminally modified by addition of either a nuclear localization sequence (NLS) or a STOP codon to address the impact of their intracellular distribution. FACS based cell cycle analysis revealed that expression of nearly all pKi-67 domains and the antisense oligonucleotide led to a decreased amount of cells in S-phase and an increased number of cells in G(2)/M- and G(1)-phase. Subsequent analysis of the endogenous pKi-67 mRNA and protein levels revealed that the constructs with the most significant impact on the cell cycle were able to silence pKi-67 transcription as well. We conclude from the data that pKi-67 influences progression of S-phase and mitosis in a self-regulated manner and, therefore, effects the cell cycle checkpoints within both phases. Furthermore, we found pKi-67 mediates an anti-apoptotic effect on the cell and we verified that this marker, although it is a potential ribosomal catalyst, is not expressed in differentiated tissues with a high transcriptional activity. Copyright 2002 Wiley-Liss, Inc.

  11. Grafting of a novel gold(III) complex on nanoporous MCM-41 and evaluation of its toxicity in Saccharomyces cerevisiae.

    Science.gov (United States)

    Fazaeli, Yousef; Amini, Mostafa M; Ashourion, Hamed; Heydari, Homayoun; Majdabadi, Abbas; Jalilian, Amir Reza; Abolmaali, Shamsozoha

    2011-01-01

    The goal of this research was to investigate the potential of newly synthesized gold complex trichloro(2,4,6-trimethylpyridine)Au(III) as an anticancer agent. The gold(III) complex was synthesized and grafted on nanoporous silica, MCM-41, to produce AuCl(3)@PF-MCM- 41 (AuCl(3) grafted on pyridine-functionalized MCM-41). The toxicity of trichloro(2,4,6- trimethylpyridine)Au(III) and AuCl(3)@PF-MCM-41 in Saccharomyces cerevisiae (as a model system) was studied. The gold(III) complex showed a mid cytotoxic effect on yeast viability. Using the drug delivery system, nanoporous MCM-41, the gold(III) complex became a strong inhibitor for growth of yeast cells at a very low concentration. Furthermore, the animal tests revealed a high uptake of AuCl(3)@PF-MCM-41 in tumor cells. The stability of the compound was confirmed in human serum.

  12. High selectivity and stability of Mg-doped Al-MCM-41 for in-situ catalytic upgrading fast pyrolysis bio-oil

    International Nuclear Information System (INIS)

    Karnjanakom, Surachai; Suriya-umporn, Thanyamai; Bayu, Asep; Kongparakul, Suwadee; Samart, Chanatip; Fushimi, Chihiro; Abudula, Abuliti; Guan, Guoqing

    2017-01-01

    Highlights: • Mg-doped Al-MCM-41 was developed for in-situ catalytic upgrading of bio-oils. • Mg/Al-MCM-41 exhibited high selectivity to aromatic hydrocarbons. • The ratio of produced hydrocarbon reached up to 80% in upgraded bio-oil. • 1 wt.% Mg/Al-MCM-41 showed the highest catalytic activity. • Mg/Al-MCM-41 had stable reusability due to its coking inhabitation ability. - Abstract: In-situ catalytic upgrading of bio-oils derived from the fast pyrolysis of cellulose, lignin or sunflower stalk over Mg-doped Al-MCM-41 was investigated in details. It is found that Mg species with doping amounts ranged between 0.25 and 10 wt.% was well dispersed on Al-MCM-41, and that doping Mg on Al-MCM-41 effectively adjusted the acidity and basicity of the catalysts, resulting in significant improvement of bio-oil quality. Mg/Al-MCM-41 exhibited high selective conversion of bio-oils derived from cellulose, lignin or sunflower stalk to high value-added aromatic hydrocarbons via catalytic cracking, deoxygenation and aromatization. In the upgraded bio-oil, the relative total hydrocarbon amount reached up to approximately ≥80%, which consisted of aromatic hydrocarbon approximately 76% and aliphatic hydrocarbon approximately 4% for all feedstocks. The selectivity to the monocyclic aromatic hydrocarbons (MAHs) such as benzene, toluene and xylenes (BTXs) increased while the coke formed on the catalyst decreased with the increase in Mg doping amount. 1 wt.% Mg/Al-MCM-41 resulted in the highest relative total hydrocarbon amount in the upgraded bio-oil at lower catalytic deoxygenation temperature, and showed stable reusability for at least 5 cycles. It is expected that Mg/Al-MCM-41 can be widely applied for bio-oil upgrading in a practical process.

  13. Catalytic copyrolysis of particle board and polypropylene over Al-MCM-48

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hannah; Choi, Suek Ju [School of Environmental Engineering, University of Seoul, Seoul 02504 (Korea, Republic of); Kim, Ji Man [Department of Chemistry, Sungkyunkwan University, Suwon 16419 (Korea, Republic of); Jeon, Jong-Ki [Department of Chemical Engineering, Kongju National University, Cheonan 31080 (Korea, Republic of); Park, Sung Hoon; Jung, Sang-Chul [Department of Environmental Engineering, Sunchon National University, Suncheon 57922 (Korea, Republic of); Kim, Sang Chai [Department of Environmental Education, Mokpo National University, Muan 58554 (Korea, Republic of); Park, Young-Kwon, E-mail: catalica@uos.ac.kr [School of Environmental Engineering, University of Seoul, Seoul 02504 (Korea, Republic of)

    2016-10-15

    Highlights: • Al-MCM-48 was used for catalytic copyrolysis of particle board and polypropylene. • Catalytic produced mainly hydrocarbons. • The hydrocarbons produced were mainly in the diesel range. - Abstract: Particle board and polypropylene (PP) at a mixing ratio of 1:1 were copyrolyzed over two Al-MCM-48 catalysts with Si/Al ratios of 20 and 80. The catalyst characteristics were examined by measuring the Brunauer-Emmett-Teller surface area, temperature programmed desorption of ammonia, and X-ray diffraction. The main pyrolysis products of particle board were oxygenates, acids, and phenolics, whereas a large quantity of hydrocarbons within the diesel fuel range was produced from copyrolysis with polypropylene. The catalytic copyrolysis of particle board and PP over the Al-MCM-48 catalysts produced bio-oil with a much larger hydrocarbon content than that from the catalytic pyrolysis of particle board only. The hydrocarbons produced were mainly in the diesel range, highlighting the potential for the production of high-quality fuel.

  14. OM4 bend insensitive multi-mode fibers’ usefulness for MCM integration

    International Nuclear Information System (INIS)

    Guzowski, Bartłomiej; Lisik, Zbigniew; Tosik, Grzegorz; Ciupa, Emilia

    2012-01-01

    Highlights: ► The influence of high temperature exposure on OM4 fibers’ mechanical properties. ► Researching OM4 class fibers for use in innovative Optical Multi Chip Module. ► The influence of bending at a very small radius, up to 2 mm, on MM fibers. - Abstract: For future generations of electronic systems, a severe bottleneck is expected on the interconnection level and the use of optical interconnection is considered as one of the most promising solutions in this matter. Recent progress in fiber development resulted in new generation of optical fibers that are bend insensitive. This makes them ideal for Multi Chip Module (MCM) application. This paper focuses on OM4 bend insensitive multi-mode fibers’ usefulness for MCM integration, particularly the investigation of MM fiber loss is presented, which is influenced by bend diameter and the fiber's mechanical performance under influence of high temperature (400 °C–1000 °C adequate to MCM production process).

  15. Demonstration of the proliferation marker Ki-67 in renal biopsies: correlation to clinical findings.

    Science.gov (United States)

    Nabokov, A; Waldherr, R; Ritz, E

    1997-07-01

    Assessment of cell proliferation in renal biopsy samples is a potentially promising analytical tool to evaluate disease activity. So far no information is available on the correlation between proliferative activity in different anatomic compartments of the kidney and clinical symptoms. To elucidate this issue, we examined renal biopsy specimens from 20 patients with systemic vasculitis (15 Wegener's granulomatosis, five microscopic polyangiitis), 20 patients with immunoglobulin (Ig) A nephropathy (IgAN), 13 patients with minimal-change disease (MCD), 11 patients with tubulointerstitial nephritis, and five patients with diabetes mellitus. The streptavidin-biotin-peroxidase complex technique was applied to autoclave-pretreated, formalin-fixed, paraffin-embedded tissue sections to label different cell types with the antibody MIB1 directed against the Ki-67 antigen. Proliferation index (PI) was estimated as the number of positively stained nuclei per glomerular cross-section or per square millimeter section area. The interstitial cells were discriminated by additional staining of Ki-67-processed samples with specific immune markers. In patients with vasculitis, PI was considerably elevated in the extracapillary glomerular compartment (0.86), in proximal tubules (6.24), and in the interstitium (8.62). High proliferative activity was also noted in interstitium (3.98) and proximal tubules (1.35) of patients with IgAN. Of particular interest was the increased interstitial proliferative activity (15.0) in diabetic patients. Resident renal cells, but not infiltrating cells, seemed to constitute the majority of the proliferating cell population in the interstitium. In systemic vasculitis, clinical disease activity was significantly correlated to endocapillary (r(s) = 0.58), extracapillary (r(s) = 0.67), proximal tubular (r(s) = 0.67), and interstitial PI (r(s) = 0.61). By multiple linear regression analysis, proximal tubular PI was correlated to the presence of hematuria

  16. The 1.8-Å crystal structure of the N-terminal domain of an archaeal MCM as a right-handed filament.

    Science.gov (United States)

    Fu, Yang; Slaymaker, Ian M; Wang, Junfeng; Wang, Ganggang; Chen, Xiaojiang S

    2014-04-03

    Mini-chromosome maintenance (MCM) proteins are the replicative helicase necessary for DNA replication in both eukarya and archaea. Most of archaea only have one MCM gene. Here, we report a 1.8-Å crystal structure of the N-terminal MCM from the archaeon Thermoplasma acidophilum (tapMCM). In the structure, the MCM N-terminus forms a right-handed filament that contains six subunits in each turn, with a diameter of 25Å of the central channel opening. The inner surface is highly positively charged, indicating DNA binding. This filament structure with six subunits per turn may also suggests a potential role for an open-ring structure for hexameric MCM and dynamic conformational changes in initiation and elongation stages of DNA replication. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. CO interaction with Cu(I)-MCM-22 zeolite: density function theory investigation

    International Nuclear Information System (INIS)

    Viet Thang Ho; Petr Nachtigall

    2014-01-01

    MCM-22 zeolite has been widely used in many applications for catalysis and adsorption. Especially, this material exchanged with Cu + cation (Cu(I)-MCM-22) is an active catalyst in green chemical reaction, such as decomposition of NO and N 2 O. The local geometry of Cu + in vicinity of Al (III) replacement in six different Si (IV) sites and CO interaction with the most stable Cu + in each Al site were explored using periodic density functional theory (DFT) method. Th CO stretching frequencies were computed applying the ω/r scaling method in which frequencies were determined at high quantum level (couple cluster) and CO bond length calculated at DFT level. The results showed that Cu + cation located in the channel wall position and intersection position coordinated with 3 or 2 framework oxygen atoms, respectively, before CO adsorption and Cu + cation coordinated with 2 framework oxygen atoms after CO adsorption. The interaction energies between CO and Cu + cation were in range -148 to -195 kJ/mol -1 and CO frequencies exhibit two peak at 2151 and 2159 cm -1 in good agreement with experimental data. This investigation allows to understand the Cu + location in MCM-22 and CO adsorption in Cu(I)-MCM-22 zeolite. (author)

  18. FBXW7 Acts as an Independent Prognostic Marker and Inhibits Tumor Growth in Human Osteosarcoma

    Directory of Open Access Journals (Sweden)

    Zhanchun Li

    2015-01-01

    Full Text Available F-box and WD repeat domain-containing 7 (FBXW7 is a potent tumor suppressor in human cancers including breast cancer, colorectal cancer, gastric cancer and hepatocellular carcinoma. In this study, we found that the expressions of FBXW7 protein and mRNA levels in osteosarcoma (OS cases were significantly lower than those in normal bone tissues. Clinical analysis indicated that FBXW7 was expressed at lower levels in OS patients with advanced clinical stage, high T classification and poor histological differentiation. Furthermore, we demonstrated that high expression of FBXW7 was correlated with a better 5-year survival of OS patients. Multivariate Cox regression analysis indicated that FBXW7 was an independent prognostic marker in OS. Our in vitro studies showed that FBXW7 overexpression inhibited cell cycle transition and cell proliferation, and promoted apoptosis in both U2OS and MG-63 cells. In a nude mouse xenograft model, FBXW7 overexpression slowed down tumor growth by inducing apoptosis and growth arrest. Mechanistically, FBXW7 inversely regulated oncoprotein c-Myc and cyclin E levels in both U2OS and MG-63 cells. Together these findings suggest that FBXW7 may serve as a prognostic biomarker and inhibit tumor progression by inducing apoptosis and growth arrest in OS.

  19. Synthesis of zeolite MCM-22 tetraethyl orthosilicate using alternative as source of silica

    International Nuclear Information System (INIS)

    Santos, E.R.F. dos; Barbosa, A.S.; Rodrigues, M.G.F.

    2011-01-01

    Currently methods are being sought are more diligent in the synthesis of zeolite MCM-22, where it is considered promising when used as catalysts and adsorbents for environmental protection. This work aims to synthesize the zeolite MCM-22 by replacing the conventionally used silica source, tetraethyl by, thereby providing a reduction in the duration of synthesis. This material was characterized by X ray diffraction and scanning electron microscopy. XRD of zeolite MCM-22 showed peaks typical topology composed of the lamellar layers intercalated with organic molecules that are components of the director (HMI). Scanning electron micrograph shows the structure in form of very thin thickness blades that grow in the form of spherical structures resulting from the agglomeration of these particles. (author)

  20. 78 FR 36017 - MCM Rail Services LLC, d/b/a Baltimore Industrial Railroad-Operation Exemption-Hilco SP Rail, LLC

    Science.gov (United States)

    2013-06-14

    ... DEPARTMENT OF TRANSPORTATION Surface Transportation Board [Docket No. FD 35725] MCM Rail Services LLC, d/b/a Baltimore Industrial Railroad-- Operation Exemption--Hilco SP Rail, LLC MCM Rail Services LLC, d/b/a Baltimore Industrial Railroad (MCM), a noncarrier, has filed a verified notice of exemption...

  1. 11C-radioisotope study of methanol co-reaction with ethanol over Ni-MCM-41 silica-alumina and Ni-alumina

    International Nuclear Information System (INIS)

    Sarkadi-Priboczki, E.; Kovacs, Z.; Tsoncheva, T.; Kumar, N.; Murzin, D.Yu.

    2009-01-01

    Complete text of publication follows. The Ni modifies the properties of acidic alumina and light acidic MCM-41 silica-alumina supports. The radioisotopic method is a suitable tool for distinction of the 11 Cradioisotopic methanol and its co-derivates from derivates of non-radioactive ethanol on these catalysts. Experimental. The Ni/A l 2O 3 (5 wt % Ni) is commercially available while H-MCMN-41 (Si/Al=20) and Ni-ion-exchanged MCM-41 silica-alumina (5 wt % Ni) were prepared and characterized in previous works. Before catalysis the Ni/Al 2 O 3 and Ni-MCM-41 were pre-reduced. The 11 C-methanol was formed by a radiochemical process from 11 C-carbon dioxide produced at cyclotron (T 1/2 = 20.4 min). The mixture of equivalent volume of radioactive methanol and non-radioactive ethanol was introduced into glass tube micro-flow reactor at ambient temperature. After adsorption, the valves were closed and the catalyst was heated up to the required temperatures. The desorption rate of the remaining 11 C-derivatives on catalysts were continuously followed by radiodetectors and the derivatives of methanol with ethanol were analyzed by Radio/FID-gas chromatography (FID is coupled on-line with a radiodetector). The ethanol and its derivates were identified by FID while the 11 C-methanol and its co-derivates (with ethanol) were detected by both of FID and radiodetector. Results The 11 C-dimethyl ether was the common product of the single 11 C-methanol transformation on H-MCM-41, Ni-MCM-41 and Ni- Al 2 O 3 at low temperature (200-280 degC) due to middle strong acid sites. At higher temperature (280-350 degC), the dimethyl ether and hydrocarbons were the dominant products on H-MCM-41 while dimethyl ether selectivity decreased on Ni-alumina and Ni-MCM-41 in favor of methane. The selectivities of methanol to formaldehyde and methane were the highest on Ni-MCM-41. During co-reaction of 11 C-methanol with non-radioactive ethanol, the 11 C-labeled coethers, namely 11 C-methyl ethyl ether

  2. Mcm1p binding sites in ARG1 positively regulate Gcn4p binding and SWI/SNF recruitment

    OpenAIRE

    Yoon, Sungpil; Hinnebusch, Alan G.

    2009-01-01

    Transcription of the arginine biosynthetic gene ARG1 is activated by Gcn4p, a transcription factor induced by starvation for any amino acid. Previously we showed that Gcn4p binding stimulates the recruitment of Mcm1p and co-activator SWI/SNF to ARG1 in cells via Gcn4p induction through amino acid starvation. Here we report that Gcn4p binding is reduced by point mutations of the Mcm1p binding site and increased by overexpression of Mcm1p. This result suggests that Mcm1p plays a positive role i...

  3. Laccase immobilized on methylene blue modified mesoporous silica MCM-41/PVA

    International Nuclear Information System (INIS)

    Xu Xinhua; Lu Ping; Zhou Yumei; Zhao Zhenzhen; Guo Meiqing

    2009-01-01

    The mesoporous silica sieve MCM-41 containing methylene blue (MB) provides a suitable immobilization of biomolecule matrix due to its uniform pore structure, high surface areas, good biocompatibility and nice conductivity. Based on this, a facilely fabricated amperometric biosensor by entrapping laccase into the MB modified MCM-41/PVA composite film has been developed. Laccase from Trametes versicolor is assembled on a composite film of MCM-41 containing MB/PVA modified Au electrode and the electrode is characterized with respect to transmission electron microscopy (TEM) and scanning electron microscopic (SEM), Cyclic voltammetry (CV), response time, detection limit, linear range and activity of laccase. The laccase modified electrode remains good redox behavior in pH 4.95 acetate buffer solution, at room temperature in present of 0.1 mM catechol. The response time (t 90% ) of the modified electrode is less than 4 s for catechol. The detection limit is 0.331 μM and the linear detect range is about from 4.0 μM to 87.98 μM for catechol with a correlation coefficient of 0.99913(S/N = 3). The apparent Michaelis-Menten (K M app ) is estimated using the Lineweaver-Burk equation and the K M app value is about 0.256 mM. This work demonstrated that the mesoporous silica MCM-41 containing MB provides a novel support for laccase immobilization and the construction of biosensors with a faster response and better bioactivity.

  4. Study of the influence of the silica source on the synthesis of the zeolite precursor MCM-22

    International Nuclear Information System (INIS)

    Barbosa, A.S.; Santos, E.R.F. dos; Leite, R.C.N.; Rodrigues, M.G.F.

    2012-01-01

    Zeolite MCM-22 precursors were synthesized under hydrothermal conditions in systems with hexamethyleneimine HMI as bulking agent (driver). Synthesis parameter, such as sources of silica (aerosil® and quartz) was modified to investigate the effects on the morphology and crystallization in precursor MCM-22 zeolite. The products were characterized by X-Ray Diffraction (XRD), Energy Dispersive Spectroscopy (EDX) and Scanning Electron Microscopy (SEM). According to, the X-ray diffraction showed the same characteristic peaks of zeolite MCM-22. It was found that the parameter in this work of synthesis, silica source, affects the hydrothermal synthesis of zeolite MCM-22 precursor. This can be evidenced by the different morphologies found using the different sources of silica. (author)

  5. Removal of tetracycline from aqueous solution by MCM-41-zeolite A loaded nano zero valent iron: Synthesis, characteristic, adsorption performance and mechanism.

    Science.gov (United States)

    Guo, Yige; Huang, Wenli; Chen, Bin; Zhao, Ying; Liu, Dongfang; Sun, Yu; Gong, Bin

    2017-10-05

    In this study, nano zero valent iron (NZVI) modified MCM-41-zeolite A (Fe-MCM-41-A) composite as a novel adsorbent was prepared by precipitation method and applied for tetracycline (TC) removal from aqueous solution. The adsorbent was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and N 2 -BET analysis. Hysteresis loops indicated that the sample has a desirable magnetic property and can be separated quickly. Adsorption studies were carried out to evaluate its potential for TC removal. Results showed that the optimal Fe-MCM-41-A dosage, initial pH and reaction time at initial TC concentration of 100mgL -1 solution are 1gL -1 , pH=5, and 60 min respectively, at which the removal efficiency of TC was 98.7%. The TC adsorption results fitted the Langmuir isotherm model very well and the adsorption process could be described by a pseudo-second-order kinetic model. A maximum TC adsorption capacity of 526.32mgg -1 was achieved. This study demonstrates that Fe-MCM-41-A is a promising and efficient material for TC adsorption from aqueous solution. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Effects of surface acidities of MCM-41 modified with MoO{sub 3} on adsorptive desulfurization of gasoline

    Energy Technology Data Exchange (ETDEWEB)

    Shao Xinchao, E-mail: sxc86@yahoo.cn [Key Laboratory of Petrochemical Catalytic Science and Technology, Liaoning ShiHua University, Fushun 113001 (China); Zhang Xiaotong; Yu Wenguang; Wu Yuye [Key Laboratory of Petrochemical Catalytic Science and Technology, Liaoning ShiHua University, Fushun 113001 (China); Qin Yucai [Key Laboratory of Petrochemical Catalytic Science and Technology, Liaoning ShiHua University, Fushun 113001 (China); College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, Shandong 257061 (China); Sun Zhaolin [Key Laboratory of Petrochemical Catalytic Science and Technology, Liaoning ShiHua University, Fushun 113001 (China); School of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Song Lijuan, E-mail: lsong56@263.net [Key Laboratory of Petrochemical Catalytic Science and Technology, Liaoning ShiHua University, Fushun 113001 (China) and College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, Shandong 257061 (China)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer The MoO{sub 3}-MCM-41 samples prepared by spontaneous monolayer dispersion and impregnation with a different MoO{sub 3} filling have been studied. Black-Right-Pointing-Pointer The relative concentration of hydroxyl groups present on before and after containing MoO{sub 3} samples was monitored by in situ FTIR to speculate the bonding style of MoO{sub 3} and MCM-41. Black-Right-Pointing-Pointer The surface acidities of the MoO{sub 3}-MCM-41 adsorbents were investigated systematically and correlated with the desulfurization performance. - Abstract: A series of MCM-41 samples containing molybdenum oxide as active species in the mesoporous channels loaded by spontaneous monolayer dispersion (SMD) and impregnation (IM) have been prepared and characterized using XRD, N{sub 2} adsorption-desorption analysis, Fourier transform infrared spectroscopy (FTIR) and intelligent gravimetric analyzer (IGA). The relative number of hydroxy on the adsorbents was investigated by in situ FTIR. Surface acidities of the adsorbents were studied by infrared spectroscopy of adsorbed pyridine and correlated with reactivity for adsorptive desulfurization. The IGA technique was employed to investigate adsorption behavior of thiophene and benzene on the adsorbents at 303 K. It is shown that MoO{sub 3} can be highly dispersed up to 0.2 g g{sup -1} in the MCM-41 channels by the SMD strategy with the ordered mesoporous structure of the MoMM samples remaining intact. The ordered mesostructure of MCM-41 is, however, destroyed at higher MoO{sub 3} contents of 0.26 and 0.32 g g{sup -1} with particle sizes of 1.2 nm and 3.6 nm, respectively, observed. For the MoMI(0.2) sample prepared by the IM method, the aggregation of the MoO{sub 3} particles takes place with a particle size of 6.5 nm obtained. The results are also revealed that the dispersion extent of the MoO{sub 3} species is related to the abundant surface hydroxy of MCM-41. The host species and guest

  7. Selective catalytic reduction of NO{sub x} in lean-burn engine exhaust over a Pt/V/MCM-41 catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Jong Yeol; Kim, Hee Young [Division of Advanced Chemical Technology, Korea Reasearch Institute of Chemical Technology, P.O. Box 107, Yusong, Taejon 305-600 (Korea, Republic of); Woo, Seong Ihl [Department of Chemical and Biomolecular Engineering, Center for Ultramicrochemical Process Systems, Korea Advanced Institute of Science and Technology, 373-1, Kusong-dong, Yusong-gu, Taejon, 305-701 (Korea, Republic of)

    2003-09-08

    The activities of Pt supported on various metal-substituted MCM-41 (V-, Ti-, Fe-, Al-, Ga-, La-, Co-, Mo-, Ce-, and Zr-MCM-41) and V-impregnated MCM-41 were investigated for the reduction of NO by C{sub 3}H{sub 6}. Among these catalysts, Pt supported on V-impregnated MCM-41 showed the best activity. The maximum conversion of NO into N{sub 2}+N{sub 2}O over this Pt/V/MCM-41 catalyst (Pt=1wt.%, V=3.8wt.%) was 73%, and this maximum conversion was sustained over a temperature range of 70C from 270 to 340C. The high activity of Pt/V/MCM-41 over a broad temperature range resulted from two additional reactions besides the reaction occurring on usual supported Pt, the reaction of NO with surface carbonaceous materials, and the reaction of NO occurring on support V-impregnated MCM-41. The former additional reaction showed an oscillation characteristic, a phenomenon in which the concentrations of parts of reactant and product gases oscillate continuously. At low temperature, some water vapor injected into the reactant gas mixture promoted the reaction occurring on usual supported Pt, whereas at high temperature, it suppressed the additional reaction related to carbonaceous materials. Five-hundred parts per million of SO{sub 2} added to the reactant gas mixture only slightly decreased the NO conversion of Pt/V/MCM-41.

  8. Influence of crystallization time on structural and morphological characteristics the precursor of zeolite MCM-22

    International Nuclear Information System (INIS)

    Barbosa, A.S.; Lima, L.A.; Sousa, B.V.; Santos, Everton R.F. dos; Rodrigues, M.G.F.

    2009-01-01

    The zeolite MCM-22 has been studied extensively as a promising catalyst because of the high thermal stability and high activity for acid catalysis and selectivity of molecular shape. The synthesis of MCM-22 is carried out by hydrothermal treatment and long times required for complete crystallization gradual growth of crystals of 10-14 days for the synthesis of static. This work aims to synthesize the precursor of zeolite MCM-22 using the method of hydrothermal synthesis with a reduction in crystallization time of 8 and 9 days. The precursor of zeolite MCM-22 was obtained using sources of silica, soda, deionized water and the director of structures hexametilenoimina (HMI). The samples were synthesized at 150° C for 8 to 9 days, with the following molar composition: 0.511 SiO 2 : 0.039 NaOH: 0.024 Al 2 O 3 : 23.06 H 2 O and subjected to characterizations by X-ray diffraction (XRD), scanning electron microscopy ( SEM) and energy dispersive (EDX). According to tests carried out showed that the hydrothermal treatment used to synthesize the precursor of zeolite MCM-22 was effective during times of crystallization of 8 and 9 days. The results for the micrographs showed that the samples consist of clusters and / or aggregates of small crystals. (author)

  9. Hydroconversion of methyl laurate on bifunctional Ni2P/AlMCM-41 catalyst prepared via in situ phosphorization using triphenylphosphine

    Science.gov (United States)

    Zhao, Sha; Zhang, Zhena; Zhu, Kongying; Chen, Jixiang

    2017-05-01

    A series of Ni2P/AlMCM-41-x bifunctional catalysts with different Si/Al ratios (x) were synthesized by in situ phosphorization of Ni/AlMCM-41-x with triphenylphosphine (nominal Ni/P ratio of 0.75) at 300 °C on a fixed-bed reactor. For comparison, NiP/AlMCM-41-5-TPR was also prepared by the TPR method from the supported nickel phosphate with the Ni/P ratio of 1.0, during which metallic Ni rather than Ni2P formed. TEM images show that Ni and Ni2P particles uniformly distributed in Ni2P/AlMCM-41-x and NiP/AlMCM-41-5-TPR. The Ni2P/AlMCM-41-x acidity increased with decreasing the Si/Al ratio. In the hydroconversion of methyl laurate, the conversions were close to 100% on all catalysts at 360 °C, 3.0 MPa, methyl laurate WHSV of 2 h-1 and H2/methyl laurate ratio of 25. As to Ni2P/AlMCM-41-x, with decreasing the Si/Al ratio, the total selectivity to C11 and C12 hydrocarbons decreased, while the total selectivity to isoundecane and isododecane (Si-C11+i-C12) firstly increased and then decreased. Ni2P/AlMCM-41-5 gave the largest Si-C11+i-C12 of 43.2%. While NiP/AlMCM-41-5-TPR gave higher Si-C11+i-C12 than Ni2P/AlMCM-41-5, it was more active for the undesired Csbnd C bond cleavage and methanation. We propose that the in-situ phosphorization adopted here is a promising approach to preparing Ni2P-based bifunctional catalysts.

  10. MicroRNA let-7b regulates neural stem cell proliferation and differentiation by targeting nuclear receptor TLX signaling.

    Science.gov (United States)

    Zhao, Chunnian; Sun, GuoQiang; Li, Shengxiu; Lang, Ming-Fei; Yang, Su; Li, Wendong; Shi, Yanhong

    2010-02-02

    Neural stem cell self-renewal and differentiation is orchestrated by precise control of gene expression involving nuclear receptor TLX. Let-7b, a member of the let-7 microRNA family, is expressed in mammalian brains and exhibits increased expression during neural differentiation. However, the role of let-7b in neural stem cell proliferation and differentiation remains unknown. Here we show that let-7b regulates neural stem cell proliferation and differentiation by targeting the stem cell regulator TLX and the cell cycle regulator cyclin D1. Overexpression of let-7b led to reduced neural stem cell proliferation and increased neural differentiation, whereas antisense knockdown of let-7b resulted in enhanced proliferation of neural stem cells. Moreover, in utero electroporation of let-7b to embryonic mouse brains led to reduced cell cycle progression in neural stem cells. Introducing an expression vector of Tlx or cyclin D1 that lacks the let-7b recognition site rescued let-7b-induced proliferation deficiency, suggesting that both TLX and cyclin D1 are important targets for let-7b-mediated regulation of neural stem cell proliferation. Let-7b, by targeting TLX and cyclin D1, establishes an efficient strategy to control neural stem cell proliferation and differentiation.

  11. Hydroconversion of methyl laurate on bifunctional Ni{sub 2}P/AlMCM-41 catalyst prepared via in situ phosphorization using triphenylphosphine

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Sha; Zhang, Zhena [Tianjin Key Laboratory of Applied Catalysis Science and Technology, Department of Catalysis Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Zhu, Kongying, E-mail: ausky@tju.edu.cn [Analysis and Measurement Center, Tianjin University, Tianjin 300072 (China); Chen, Jixiang, E-mail: jxchen@tju.edu.cn [Tianjin Key Laboratory of Applied Catalysis Science and Technology, Department of Catalysis Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China)

    2017-05-15

    Highlights: • Bifunctional Ni{sub 2}P/AlMCM-41 was prepared by in situ phosphorization at 300 °C. • There were similar Ni{sub 2}P particle sizes in Ni{sub 2}P/AlMCM-41 with different Si/Al ratios. • The acid amount of Ni{sub 2}P/AlMCM-41 increased with decreasing the Si/Al ratio. • Ni{sub 2}P/AlMCM-41 with the Si/Al ratio of 5 had the highest activity for isomerization. • Ni{sub 2}P/AlMCM-41 had very low activity for methanation and C−C bond hydrogenolysis. - Abstract: A series of Ni{sub 2}P/AlMCM-41-x bifunctional catalysts with different Si/Al ratios (x) were synthesized by in situ phosphorization of Ni/AlMCM-41-x with triphenylphosphine (nominal Ni/P ratio of 0.75) at 300 °C on a fixed-bed reactor. For comparison, NiP/AlMCM-41-5-TPR was also prepared by the TPR method from the supported nickel phosphate with the Ni/P ratio of 1.0, during which metallic Ni rather than Ni{sub 2}P formed. TEM images show that Ni and Ni{sub 2}P particles uniformly distributed in Ni{sub 2}P/AlMCM-41-x and NiP/AlMCM-41-5-TPR. The Ni{sub 2}P/AlMCM-41-x acidity increased with decreasing the Si/Al ratio. In the hydroconversion of methyl laurate, the conversions were close to 100% on all catalysts at 360 °C, 3.0 MPa, methyl laurate WHSV of 2 h{sup −1} and H{sub 2}/methyl laurate ratio of 25. As to Ni{sub 2}P/AlMCM-41-x, with decreasing the Si/Al ratio, the total selectivity to C11 and C12 hydrocarbons decreased, while the total selectivity to isoundecane and isododecane (S{sub i-C11+i-C12}) firstly increased and then decreased. Ni{sub 2}P/AlMCM-41-5 gave the largest S{sub i-C11+i-C12} of 43.2%. While NiP/AlMCM-41-5-TPR gave higher S{sub i-C11+i-C12} than Ni{sub 2}P/AlMCM-41-5, it was more active for the undesired C−C bond cleavage and methanation. We propose that the in-situ phosphorization adopted here is a promising approach to preparing Ni{sub 2}P-based bifunctional catalysts.

  12. Synthesis of ZnO-CuO/MCM-48 photocatalyst for the degradation of organic pollutions.

    Science.gov (United States)

    Duan, Yongzheng; Shen, Yulian

    2017-07-01

    The photocatalytic properties of ZnO-CuO catalysts supported on siliceous MCM-48 (Mobil Composition of Matter No. 48) for the degradation of organic pollutions such as methylene blue and salicylic acid under UV light irradiation were investigated. These catalysts were prepared by impregnation of MCM-48 with a mixed aqueous solution of copper acetate and zinc acetate. X-ray diffraction, N 2 -physisorption, high resolution transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and photoluminescence were used to characterize these samples. Results from characterizations showed that the addition of ZnO to CuO/MCM-48 could markedly improve the photocatalytic degradation properties. The enhanced photocatalytic behaviors of ZnO-CuO/MCM-48 may be due to the formation of p-n heterojunctions between ZnO and CuO, resulting in the effective separation of photogenerated electron-hole pairs. Moreover, the photocatalysts were easily recovered and reused for five cycles without considerable loss of activity.

  13. Response of Fibroblasts MRC-5 to Flufenamic Acid-Grafted MCM-41 Nanoparticles

    Directory of Open Access Journals (Sweden)

    Giovanna Gomes Lara

    2018-01-01

    Full Text Available Recently, flufenamic acid (FFA was discovered among fenamates as a free radical scavenger and gap junction blocker; however, its effects have only been studied in cancer cells. Normal cells in the surroundings of a tumor also respond to radiation, although they are not hit by it directly. This phenomenon is known as the bystander effect, where response molecules pass from tumor cells to normal ones, through communication channels called gap junctions. The use of the enhanced permeability and retention effect, through which drug-loaded nanoparticles smaller than 200 nm may accumulate around a tumor, can prevent the local side effect upon controlled release of the drug. The present work, aimed at functionalizing MCM-41 (Mobil Composition of Matter No. 41 silica nanoparticles with FFA and determining its biocompatibility with human fibroblasts MRC-5 (Medical Research Council cell strain 5. MCM-41, was synthesized and characterized structurally and chemically, with multiple techniques. The biocompatibility assay was performed by Live/Dead technique, with calcein and propidium–iodide. MRC-5 cells were treated with FFA-grafted MCM-41 for 48 h, and 98% of cells remained viable, without signs of necrosis or morphological changes. The results show the feasibility of MCM-41 functionalization with FFA, and its potential protection of normal cells, in comparison to the role of FFA in cancerous ones.

  14. Response of Fibroblasts MRC-5 to Flufenamic Acid-Grafted MCM-41 Nanoparticles.

    Science.gov (United States)

    Lara, Giovanna Gomes; Cipreste, Marcelo Fernandes; Andrade, Gracielle Ferreira; Silva, Wellington Marcos da; Sousa, Edésia Martins Barros de

    2018-01-09

    Recently, flufenamic acid (FFA) was discovered among fenamates as a free radical scavenger and gap junction blocker; however, its effects have only been studied in cancer cells. Normal cells in the surroundings of a tumor also respond to radiation, although they are not hit by it directly. This phenomenon is known as the bystander effect, where response molecules pass from tumor cells to normal ones, through communication channels called gap junctions. The use of the enhanced permeability and retention effect, through which drug-loaded nanoparticles smaller than 200 nm may accumulate around a tumor, can prevent the local side effect upon controlled release of the drug. The present work, aimed at functionalizing MCM-41 (Mobil Composition of Matter No. 41) silica nanoparticles with FFA and determining its biocompatibility with human fibroblasts MRC-5 (Medical Research Council cell strain 5). MCM-41, was synthesized and characterized structurally and chemically, with multiple techniques. The biocompatibility assay was performed by Live/Dead technique, with calcein and propidium-iodide. MRC-5 cells were treated with FFA-grafted MCM-41 for 48 h, and 98% of cells remained viable, without signs of necrosis or morphological changes. The results show the feasibility of MCM-41 functionalization with FFA, and its potential protection of normal cells, in comparison to the role of FFA in cancerous ones.

  15. Photocatalytic degradation of tetracycline by Ti-MCM-41 prepared at room temperature and biotoxicity of degradation products

    Science.gov (United States)

    Zhou, Kefu; Xie, Xiao-Dan; Chang, Chang-Tang

    2017-09-01

    Ti-doped MCM-41 with different Si/Ti molar ratios was prepared at room temperature to degrade tetracycline antibiotics in aqueous solution. The Ti was doped into the skeleton structure of MCM-41. The photocatalytic activity of Ti-doped MCM-41 was investigated. The optimal catalyst had Si/Ti molar ratio of 25 and over 99% removal of oxytetracycline in 150 min, and the removal could maintain 98% after 5 reuses. Ions and soluble organic matters in natural water affected the degradation reaction when Ti-doped MCM-41 was used to treat simulated wastewater of chicken farms. The degradation products of oxytetracycline, tetracycline and chlortetracycline were detected by Escherichia coli DH5α and HPLC-MS/MS. No intermediate product with higher toxicity was detected.

  16. Effects of let-7b and TLX on the proliferation and differentiation of retinal progenitor cells in vitro.

    Science.gov (United States)

    Ni, Ni; Zhang, Dandan; Xie, Qing; Chen, Junzhao; Wang, Zi; Deng, Yuan; Wen, Xuyang; Zhu, Mengyu; Ji, Jing; Fan, Xianqun; Luo, Min; Gu, Ping

    2014-10-20

    MicroRNAs manifest significant functions in brain neural stem cell (NSC) self-renewal and differentiation through the post-transcriptional regulation of neurogenesis genes. Let-7b is expressed in the mammalian brain and regulates NSC proliferation and differentiation by targeting the nuclear receptor TLX, which is an essential regulator of NSC self-renewal. Whether let-7b and TLX act as important regulators in retinal progenitor cell (RPC) proliferation and differentiation remains unknown. Here, our data show that let-7b and TLX play important roles in controlling RPC fate determination in vitro. Let-7b suppresses TLX expression to negatively regulate RPC proliferation and accelerate the neuronal and glial differentiation of RPCs. The overexpression of let-7b downregulates TLX levels in RPCs, leading to reduced RPC proliferation and increased neuronal and glial differentiation, whereas antisense knockdown of let-7b produces robust TLX expression,enhanced RPC proliferation and decreased differentiation. Moreover, the inhibition of endogenous TLX by small interfering RNA suppresses RPC proliferation and promotes RPC differentiation. Furthermore, overexpression of TLX rescues let-7b-induced proliferation deficiency and weakens the RPC differentiation enhancement caused by let-7b alone. These results suggest that let-7b, by forming a negative feedback loop with TLX, provides a novel model to regulate the proliferation and differentiation of retinal progenitors in vitro.

  17. Transcription factor genes essential for cell proliferation and replicative lifespan in budding yeast

    Energy Technology Data Exchange (ETDEWEB)

    Kamei, Yuka; Tai, Akiko; Dakeyama, Shota; Yamamoto, Kaori; Inoue, Yamato; Kishimoto, Yoshifumi; Ohara, Hiroya; Mukai, Yukio, E-mail: y_mukai@nagahama-i-bio.ac.jp

    2015-07-31

    Many of the lifespan-related genes have been identified in eukaryotes ranging from the yeast to human. However, there is limited information available on the longevity genes that are essential for cell proliferation. Here, we investigated whether the essential genes encoding DNA-binding transcription factors modulated the replicative lifespan of Saccharomyces cerevisiae. Heterozygous diploid knockout strains for FHL1, RAP1, REB1, and MCM1 genes showed significantly short lifespan. {sup 1}H-nuclear magnetic resonance analysis indicated a characteristic metabolic profile in the Δfhl1/FHL1 mutant. These results strongly suggest that FHL1 regulates the transcription of lifespan related metabolic genes. Thus, heterozygous knockout strains could be the potential materials for discovering further novel lifespan genes. - Highlights: • Involvement of yeast TF genes essential for cell growth in lifespan was evaluated. • The essential TF genes, FHL1, RAP1, REB1, and MCM1, regulate replicative lifespan. • Heterozygous deletion of FHL1 changes cellular metabolism related to lifespan.

  18. A secondary, coplanar design Ni/MCM-41/Zn microbattery

    Science.gov (United States)

    Meskon, S. R.; Othman, R.; Ani, M. H.

    2018-01-01

    A secondary Ni/Zn microbattery (∼200 µm thick) has been developed in a coplanar electrode configuration. The cell is essentially of a circular shape (∼30 mm in diameter) consisting of a fine circular ring (cathode) and a circle (anode) split apart (~800 µm). Unlike the stacking cell architecture, coplanar configuration offers simple design, ease of fabrication and eventually cost saving. The use of MCM-41 mesoporous silica as the membrane separator cum electrolyte reservoir enables the successful implementation of coplanar configuration. The fabrication of Ni/Zn microbattery first begins with electrodeposition of zinc (Zn) and nickel hydroxide (Ni(OH)2) thin films onto patterned FR4 printed circuit board, followed by deposition of zinc oxide (ZnO) slurry onto the zinc active layer, and finally ends by multiple drop-coating procedures of MCM-41 from its precursor solution at ambient temperature. Once a potassium hydroxide (6 M KOH)/MCM-41 electrolyte-separator mixture is incorporated, the cell is sealed with an acrylic sheet and epoxy adhesive. The fabricated microbatteries were capable to sustain around 130 deep charge-discharge cycles. When rated at 0.1 mA, the energy density of the microbattery was around 3.82 Wh l-1 which is suitable for low rate applications and storage for micro energy harvesters such as piezoelectric generators.

  19. MCM-41 ordered mesoporous molecular sieves synthesis and characterization

    Directory of Open Access Journals (Sweden)

    Rogério A.A. Melo

    1999-07-01

    Full Text Available The aim of this work was to study the hydrothermal synthesis of Si and SiAlMCM-41 performed under both autogenic pressure and refluxing conditions. XRD data showed that the MCM-41 phase may be formed by both processes and that the synthesized material in the presence of Al and/or under reflux presents the hexagonally arrangement of less ordered mesopores. However, as verified by XRD and physisorption data, the order was improved with higher synthesis times. 29Si and 1H - 29Si C/P MAS NMR spectra showed that a great part of the Si atoms exists as silanol groups which originate resonance peaks at -110, -100 and -91 ppm. The presence of Al atoms may generate Si(3Si, Al and Si(2Si, 2Al environments which might be contributing to resonance peaks at -100 and -91 ppm. The 27Al MAS NMR spectrum of the as synthesized AlSiMCM-41 showed a resonance peak of tetrahedral framework aluminum close to 53 ppm and two others, one close to 14 ppm attributed to Al(H2O6+3 species and the other a weak signal close to 32 ppm attributed to pentacoordinated Al. 27Al MAS NMR spectra of the calcined sample showed a peak at 0 ppm corresponding to an hexacoordinated extra-framework aluminum formed during calcination.

  20. Synthesis of MCM-41 nanomaterial from Algerian bentonite ...

    African Journals Online (AJOL)

    Mesoporous materials of the MCM-41 type were synthesized from Algerian bentonite as an aluminosilicate source without the addition of pure silica and aluminum reagents. The samples were synthesized under hydrothermal condition using cetyltrimithylammonium bromide (CTAB) as surfactant. The influence of initial ...

  1. Study of the influence in crystallization period in MCM-22 zeolite synthesis

    International Nuclear Information System (INIS)

    Barbosa, A.S.; Santos, E.R.F.; Rodrigues, M.G.F.

    2011-01-01

    The synthesis of MCM-22 is accomplished by hydrothermal treatment and long periods needed for crystallization, with the gradual growth of crystals of 10-14 days. MCM-22 catalyst is studied intensively as promising, with high thermal stability. As part of a line of research focused on the development of zeolite with lowest cost, this study aimed to examine the effect in decreasing the period of crystallization in the synthesis of zeolite MCM-22. The materials were characterized by X-ray diffraction (XRD) spectroscopy, X-ray Energy Dispersive (EDX) and Fourier transform infrared spectroscopy and Fourier transform (FT-IR). By XRD it was observed that the hydrothermal treatment used in the synthesis was effective during periods of crystallization and EDX was observed that the samples have a high percentage of silica and low alumina content, which gives them a high ratio SiO 2 /Al 2 O 3 characteristic of the MWW structure. (author)

  2. Ce, Ti modified MCM-48 mesoporous photocatalysts: Effect of the synthesis route on support and metal ion properties

    Science.gov (United States)

    Mureseanu, Mihaela; Filip, Mihaela; Somacescu, Simona; Baran, Adriana; Carja, Gabriela; Parvulescu, Viorica

    2018-06-01

    New Ti-MCM-48 and CeTi-MCM-48 photocatalysts were obtained by impregnation of the MCM-48 silica support synthesized by a hydrothermal process with aqueous solution of Ti and Ce precursors. The immobilization of metal cations presented a low effect on the porosity, morphology and structure of MCM-48 mesoporous silica support as was evidenced by N2 adsorption-desorption, X-ray diffraction, SEM and TEM electron microscopy. EDAX analysis and X-ray photoelectron microscopy (XPS) indicated that titanium cations were present on the mesoporous silica surface only as Ti4+ species and the effect of ceria on titanium speciation was different, compared to the CeTi-MCM-48 sample, previously obtained by direct synthesis. The photocatalytic properties of mono- and bimetallic catalysts were evaluated in degradation of phenol from water and correlated with the active metallic species concentration, distribution, speciation and their interaction with the support or each other. An advanced oxidation mechanism for phenol degradation by radical species was proposed.

  3. Cell-cycle regulatory proteins in human wound healing

    DEFF Research Database (Denmark)

    Bartkova, Jirina; Grøn, Birgitte; Dabelsteen, Erik

    2003-01-01

    Proper healing of mucosal wounds requires careful orchestration of epithelial cell migration and proliferation. To elucidate the molecular basis of the lack of cellular proliferation in the migrating 'epithelial tongue' during the re-epithelialization of oral mucosal wounds, the expression of cell......-cycle regulators critical for G(1)-phase progression and S-phase entry was here analysed immunohistochemically. Compared to normal human mucosa, epithelia migrating to cover 2- or 3-day-old wounds made either in vivo or in an organotypic cell culture all showed loss of the proliferation marker Ki67 and cyclins D(1......) and A, and reduced expression of cyclins D(3) and E, the cyclin D-dependent kinase 4 (CDK4), the MCM7 component of DNA replication origin complexes and the retinoblastoma protein pRb. Among the CDK inhibitors (CKIs), p16ink4a and p21Cip1 were moderately increased and decreased, respectively, whereas...

  4. Human Homolog of Drosophila Ariadne (HHARI) is a marker of cellular proliferation associated with nuclear bodies

    Energy Technology Data Exchange (ETDEWEB)

    Elmehdawi, Fatima; Wheway, Gabrielle; Szymanska, Katarzyna [Division of Clinical Sciences, Leeds Institute of Molecular Medicine, Level 8, Wellcome Trust Brenner Building, University of Leeds, Leeds, LS9 7TF West Yorkshire (United Kingdom); Adams, Matthew [BioScreening Technology Group, Biomedical Health Research Center, Wellcome Trust Brenner Building, University of Leeds, Leeds, LS9 7TF West Yorkshire (United Kingdom); High, Alec S. [Department of Histopathology, Bexley Wing, St. James' s University Hospital, Beckett Street, Leeds, LS9 7TF West Yorkshire (United Kingdom); Johnson, Colin A., E-mail: c.johnson@leeds.ac.uk [Division of Clinical Sciences, Leeds Institute of Molecular Medicine, Level 8, Wellcome Trust Brenner Building, University of Leeds, Leeds, LS9 7TF West Yorkshire (United Kingdom); Robinson, Philip A. [Division of Clinical Sciences, Leeds Institute of Molecular Medicine, Level 8, Wellcome Trust Brenner Building, University of Leeds, Leeds, LS9 7TF West Yorkshire (United Kingdom)

    2013-02-01

    HHARI (also known as ARIH1) is an ubiquitin-protein ligase and is the cognate of the E2, UbcH7 (UBE2L3). To establish a functional role for HHARI in cellular proliferation processes, we performed a reverse genetics screen that identified n=86/522 (16.5%) ubiquitin conjugation components that have a statistically significant effect on cell proliferation, which included HHARI as a strong hit. We then produced and validated a panel of specific antibodies that establish HHARI as both a nuclear and cytoplasmic protein that is expressed in all cell types studied. HHARI was expressed at higher levels in nuclei, and co-localized with nuclear bodies including Cajal bodies (p80 coilin, NOPP140), PML and SC35 bodies. We confirmed reduced cellular proliferation after ARIH1 knockdown with individual siRNA duplexes, in addition to significantly increased levels of apoptosis, an increased proportion of cells in G2 phase of the cell cycle, and significant reductions in total cellular RNA levels. In head and neck squamous cell carcinoma biopsies, there are higher levels of HHARI expression associated with increased levels of proliferation, compared to healthy control tissues. We demonstrate that HHARI is associated with cellular proliferation, which may be mediated through its interaction with UbcH7 and modification of proteins in nuclear bodies. -- Highlights: ► We produce and validate new antibody reagents for the ubiquitin-protein ligase HHARI. ► HHARI colocalizes with nuclear bodies including Cajal, PML and SC35 bodies. ► We establish new functions in cell proliferation regulation for HHARI. ► Increased HHARI expression associates with squamous cell carcinoma and proliferation.

  5. Preparación y caracterización de la zeolita MCM-22 y de su precursor laminar

    Directory of Open Access Journals (Sweden)

    Pergher Sibele B. C.

    2003-01-01

    Full Text Available The layered precursor of MCM-22 was prepared with different Si/Al ratios: 15, 25, 50, 100 and ¥. Upon heat treatment these precursors form MCM-22 zeolite. Both layered precursor and MCM-22 zeolite were characterized by several techniques: Chemical Analysis by Atomic Absorption Spectroscopy (AAS, X-Ray Diffraction (XRD, Thermo-gravimetric Analysis (TGA, Pore Analysis by N2 and Ar adsorption, Scanning Electron Microscopy (SEM, Infrared Spectroscopy (IR and Temperature Programmed Desorption of ammonium (TPD.

  6. The Correlation of Adsorption Behavior between Ciprofloxacin Hydrochloride and the Active Sites of Fe-doped MCM-41

    Directory of Open Access Journals (Sweden)

    Ying Wu

    2018-02-01

    Full Text Available HIGHLIGHTSFe incorporation significantly accelerated the adsorption of CPX on MCM-41.Fe leaching can be ignored when pH was higher than 4.0.pH played an important role in CPX adsorption on Fe-MCM-41.Co-effect of CPX and metal cations on Fe-MCM-41 was investigated.Fe-MCM-41s with various molar ratios of silicon to iron (20, 40, 80, and 160 were prepared to investigate adsorption properties of ciprofloxacin hydrochloride (CPX in aqueous solutions. Fe-MCM-41s were characterized by transmission electron microscope (TEM, X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, nitrogen adsorption/desorption isotherms, and infrared spectroscopy (FT-IR. Effects of silicon-iron ratio, adsorbent dosage, pH, and temperature were conducted to explore the adsorption mechanism of CPX on Fe-MCM-41. The results showed that the introduction of iron facilitated the absorption quantity for CPX from 20.04 to 83.33 mg g−1 at 120 min of reaction time, which was mainly attributed to surface complexation. The promotion of hydrophobic effect, electrostatic interactions, and π-π electron donor-acceptor interaction also played coordinate roles in the adsorption process. The experimental kinetic data followed both the pseudo-second-order and intra-particle diffusion models, while the adsorption isotherm data fit well to Freundlich model at high temperature. Thermodynamic study showed that the adsorption was spontaneous. Under the effect of electrostatic interaction, pH of the solution strongly affected CPX adsorption. Five representative metal cations (Ca, Cu, Ni, Pb, and Cd were chosen to study the effects on CPX adsorption and their complexation. The inhibiting effect of metal cations on CPX adsorption was sequenced in the order of Cu > Ni > Pb > Cd > Ca, which followed the same order as the complexation stability constants between CPX and cations. The Fe-MCM-41 adsorbent possessed excellent reusability for 4 cycles use, suggesting a potential applicability of

  7. Characterization of conserved arginine residues on Cdt1 that affect licensing activity and interaction with Geminin or Mcm complex.

    Science.gov (United States)

    You, Zhiying; Ode, Koji L; Shindo, Mayumi; Takisawa, Haruhiko; Masai, Hisao

    2016-05-02

    All organisms ensure once and only once replication during S phase through a process called replication licensing. Cdt1 is a key component and crucial loading factor of Mcm complex, which is a central component for the eukaryotic replicative helicase. In higher eukaryotes, timely inhibition of Cdt1 by Geminin is essential to prevent rereplication. Here, we address the mechanism of DNA licensing using purified Cdt1, Mcm and Geminin proteins in combination with replication in Xenopus egg extracts. We mutagenized the 223th arginine of mouse Cdt1 (mCdt1) to cysteine or serine (R-S or R-C, respectively) and 342nd and 346th arginines constituting an arginine finger-like structure to alanine (RR-AA). The RR-AA mutant of Cdt1 could not only rescue the DNA replication activity in Cdt1-depleted extracts but also its specific activity for DNA replication and licensing was significantly increased compared to the wild-type protein. In contrast, the R223 mutants were partially defective in rescue of DNA replication and licensing. Biochemical analyses of these mutant Cdt1 proteins indicated that the RR-AA mutation disabled its functional interaction with Geminin, while R223 mutations resulted in ablation in interaction with the Mcm2∼7 complex. Intriguingly, the R223 mutants are more susceptible to the phosphorylation-induced inactivation or chromatin dissociation. Our results show that conserved arginine residues play critical roles in interaction with Geminin and Mcm that are crucial for proper conformation of the complexes and its licensing activity.

  8. Sulfuric acid functional zirconium (or aluminum) incorporated mesoporous MCM-48 solid acid catalysts for alkylation of phenol with tert-butyl alcohol

    International Nuclear Information System (INIS)

    Jiang, Tingshun; Cheng, Jinlian; Liu, Wangping; Fu, Lie; Zhou, Xuping; Zhao, Qian; Yin, Hengbo

    2014-01-01

    Several zirconium (or aluminum) incorporated mesoporous MCM-48 solid acid catalysts (SO 4 2− /Zr-MCM-48 and SO 4 2− /Al-MCM-48) were prepared by the impregnation method and their physicochemical properties were characterized by means of XRD, FT-IR, TEM, NH 3 -TPD and N 2 physical adsorption. Also, the catalytic activities of these solid acid catalysts were evaluated by the alkylation of phenol with tert-butyl alcohol. The effect of weight hour space velocity (WHSV), reaction time and reaction temperature on catalytic properties was also studied. The results show that the SO 4 2− /Zr-MCM-48 and SO 4 2− /Al-MCM-48 still have good mesoporous structure and long range ordering. Compared with the Zr (or Al)–MCM-48 samples, SO 4 2− /Zr-MCM-48 and SO 4 2− /Al-MCM-48 solid acid catalysts have strong acidity and exhibit high activities in alkylation reaction of phenol with tert-butyl alcohol. The SO 4 2− /Zr-MCM-48-25 (molar ratio of Si/Zr=0.04) catalyst was found to be the most promising and gave the highest phenol conversion among all catalysts. A maximum phenol conversion of 91.6% with 4-tert-butyl phenol (4-TBP) selectivity of 81.8% was achieved when the molar ratio of tert-butyl alcohol:phenol is 2:1, reaction time is 2 h, the WHSV is 2 h −1 and the reaction temperature is 140 °C. - Highlights: • Sulfuric acid functional mesoporous solid acid catalysts were prepared via impregnation method. • The alkylation of phenol with tert-butyl alcohol was carried out over these solid acid catalysts. • The catalytic activity of SO 4 2− /Zr-MCM-48-25 catalyst is much higher than that of the others. • A maximum phenol conversion of 91.6% was achieved under optimum reaction conditions for SO 4 2− /Zr-MCM-48-25

  9. Synthesis, characterization and catalytic activity toward methanol oxidation of electrocatalyst Pt4+-NH2-MCM-41

    International Nuclear Information System (INIS)

    Zheng Huajun; Chen Zuo; Wang Limin; Ma Chun’an

    2012-01-01

    Highlights: ► It was first confirmed that the Pt 4+ exhibited a good electro-catalytic property for methanol oxidation. ► The Pt 4+ perfectly distributed on a mesoporous molecular sieve matrix synthesis by a facile method. ► The good performance of catalyst resistance to poisoning because of a homogeneous distribution of Pt 4+ and large specific surface area. - Abstract: Mesoporous material with functional group (Pt 4+ -NH 2 -MCM-41) was prepared by grafting aminopropyl group and adsorbing platinum ions on the surface of the commercial molecular sieve (MCM-41). The characterization carried out by X-ray photoelectron spectroscopy, X-ray diffraction, and N 2 adsorption–desorption measurement pointed out that Pt was adsorbed on the NH 2 -MCM-41 surface as the oxidation state (Pt 4+ ) and the surface area of Pt 4+ -NH 2 -MCM-41 was up to 564 m 2 /g. Transmission electron microscopy and elemental mapping indicated a homogeneous distribution of Pt 4+ throughout all surface of the mesoporous materials. Electro-catalytic properties of methanol oxidation on the Pt 4+ -NH 2 -MCM-41 electrode were investigated with electrochemical methods. The results showed that the Pt 4+ -NH 2 -MCM-41 electrode exhibited catalytic activity in the methanol electro-oxidation with the apparent activation energy being 49.29 kJ/mol, and the control step of methanol electro-oxidation was the mass transfer process. It is first proved that platinum ions had good electro-catalytic property for methanol oxidation and provided a new idea for developing electrode materials in future.

  10. Mesoporous silica (MCM-41)-Fe2O3 as a novel magnetic nanosensor for determination of trace amounts of amino acids.

    Science.gov (United States)

    Hasanzadeh, Mohammad; Shadjou, Nasrin; Omidinia, Eskandar

    2013-08-01

    Magnetic (Fe2O3) mobile crystalline material-41 (MCM-41) was prepared and characterized using transmission electron microscopy (TEM) and nitrogen adsorption-desorption techniques. Due to the large surface area (1213 m(2)g(-1)) and remarkable electrocatalytic properties of MCM-41-Fe2O3, the MCM-41-Fe2O3 modified glassy carbon electrode (MCM-41-Fe2O3/GCE) exhibits potent electrocatalytic activity toward the electro-oxidation of amino acids. MCM-41-Fe2O3/GCE brings new capabilities for electrochemical sensing by combining the advantages of Fe2O3 magnetic nanoparticles and MCM-41 with very large surface area. Cyclic voltammetry, hydrodynamic amperometry and flow injection analysis used to determination of amino acids at higher concentration range. Fast response time, excellent catalytic activity, and ease of preparation are the advantages of the proposed amino acid sensor. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. A potential bioactive wound dressing based on carboxymethyl cellulose/ZnO impregnated MCM-41 nanocomposite hydrogel

    Energy Technology Data Exchange (ETDEWEB)

    Rakhshaei, Rasul [Research Laboratory of Dendrimers and Nanopolymers, Faculty of Chemistry, University of Tabriz, P.O. Box 51666, Tabriz (Iran, Islamic Republic of); Namazi, Hassan, E-mail: namazi@tabrizu.ac.ir [Research Laboratory of Dendrimers and Nanopolymers, Faculty of Chemistry, University of Tabriz, P.O. Box 51666, Tabriz (Iran, Islamic Republic of); Research Center for Pharmaceutical Nanotechnology, Tabriz University of Medical Science, Tabriz (Iran, Islamic Republic of)

    2017-04-01

    Lack of antibacterial activity, deficient water vapor and oxygen permeability, and insufficient mechanical properties are disadvantages of existing wound dressings. Hydrogels could absorb wound exudates due to their strong swelling ratio and give a cooling sensation and a wet environment. To overcome these shortcomings, flexible nanocomposite hydrogel films was prepared through combination of zinc oxide impregnated mesoporous silica (ZnO-MCM-41) as a nano drug carrier with carboxymethyl cellulose (CMC) hydrogel. Citric acid was used as cross linker to avoid the cytotoxicity of conventional cross linkers. The prepared nanocomposite hydrogel was characterized using X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Zeta potential and UV–vis spectroscopy. Results of swelling and erosion tests showed CMC/ZnO nanocomposite hydrogel disintegrated during the first hours of the test. Using MCM-41 as a substrate for ZnO nanoparticles solved this problem and the CMC/ZnO-MCM-41 showed a great improvement in tensile strength (12%), swelling (100%), erosion (53%) and gas permeability (500%) properties. Drug delivery and antibacterial properties of the nanocomposite hydrogel films studied using tetracycline (TC) as a broad spectrum antibiotic and showed a sustained TC release. This could efficiently decrease bandage exchange. Cytocompatibility of the nanocomposite hydrogel films has been analyzed in adipose tissue-derived stem cells (ADSCs) and results showed cytocompatibility of CMC/ZnO-MCM-41. Based on these results the prepared CMC nanocomposite hydrogel containing ZnO impregnated MCM-41, could serve as a kind of promising wound dressing with sustained drug delivery properties. - Highlights: • CMC nanocomposite hydrogel incorporated with TC loaded ZnO-MCM-41 nanoparticles have been prepared as active wound dressing. • Citric acid was used as cross linker to avoid conventional toxic crosslinkers. • CMC/ZnO-MCM-41

  12. Adsorption of toxic metal ion Cr(VI) from aqueous state by TiO2-MCM-41: equilibrium and kinetic studies.

    Science.gov (United States)

    Parida, Kulamani; Mishra, Krushna Gopal; Dash, Suresh Kumar

    2012-11-30

    This paper deals with the immobilization of various weight percentage of TiO(2) on mesoporous MCM-41, characterization of the materials by X-ray diffraction (XRD), nitrogen adsorption-desorption, Fourier Transform Infrared (FTIR) analysis, UV-vis diffuse reflectance spectroscopy (DRS) and evaluation of the adsorption capacity toward Cr(VI) removal. It is found that the MCM-41 structure retained after loading of TiO(2) but the surface area and pore diameter decreased due to pore blockage. Adsorption of Cr(VI) from aqueous state was investigated on TiO(2)-MCM-41 by changing various parameters such as pH, metal ion concentration, and the temperature. When TiO(2) loading was more than 20 wt.%, the adsorption activity (25)TiO(2)-MCM-41 reduced significantly due to considerable decrease in the surface area. It is also observed that TiO(2) and neat MCM-41 exhibits very less Cr(VI) adsorption compared to TiO(2)-MCM-41. The adsorption of Cr(VI) onto (20)TiO(2)-MCM-41 at pH~5.5 and temperature 323 K was 91% at 100mg/L Cr(VI) metal ion concentration in 80 min. The experimental data fitted well to Langmuir and Freundlich isotherms. The adsorption of Cr(VI) on TiO(2)-MCM-41 followed a second order kinetics with higher values of intra-particle diffusion rate. Thermodynamic parameters suggested that the adsorption process is endothermic in nature and desorption studies indicated a chemisorption mode. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. Cumene cracking on modified mesoporous material type MCM-41

    African Journals Online (AJOL)

    AlMCM-41 materials, the method of its exchange mode and its grains form were investigated for the mesoporous catalytic activity in the cumene (i.e. isopropylbenzene) cracking reaction. Benzene, propylene and xylene derivatives are the main ...

  14. Heterogenic expression of stem cell markers in patient-derived glioblastoma spheroid cultures exposed to long-term hypoxia

    DEFF Research Database (Denmark)

    Rosenberg, Tine; Aaberg-Jessen, Charlotte; Petterson, Stine Asferg

    2018-01-01

    AIM: To investigate the time profile of hypoxia and stem cell markers in glioblastoma spheroids of known molecular subtype. MATERIALS & METHODS: Patient-derived glioblastoma spheroids were cultured up to 7 days in either 2% or 21% oxygen. Levels of proliferation (Ki-67), hypoxia (HIF-1α, CA9...... and VEGF) and stem cell markers (CD133, nestin and musashi-1) were investigated by immunohistochemistry. RESULTS: Hypoxia markers as well as CD133 and partially nestin increased in long-term hypoxia. The proliferation rate and spheroid size were highest in normoxia. CONCLUSION: We found differences...... in hypoxia and stem cell marker profiles between the patient-derived glioblastoma cultures. This heterogeneity should be taken into consideration in development of future therapeutic strategies....

  15. Performance of Zn-Fe-Mn/MCM-48 sorbents for high temperature H2S removal and analysis of regeneration process

    Science.gov (United States)

    Huang, Z. B.; Liu, B. S.; Wang, F.; Amin, R.

    2015-10-01

    MCM-48 was synthesized using a rapid and facile process at room temperature. A series of 50%Zn-Fe-Mn/MCM-48 sorbents were prepared and their performance of hot coal gas desulfurization was investigated. High breakthrough sulfur capacity (13.2 g-S/100 g sorbent) and utilization (66.1%) of 50%1Zn2Fe2Mn/MCM-48 sorbent at 550 °C was achieved. The characterization results of XRD, BET, TPR and FT-IR revealed that MCM-48 had excellent thermal stability at less than 700 °C, ZnMn2O4 and (Mn, Zn)Fe2O4 were mainly active particles in fresh sorbents which were highly dispersed on support. The MCM-48 mesoporous structure remained intact after eight successive desulfurization/regeneration cycles. The regeneration process of 50%1Zn2Fe2Mn/MCM-48 sorbent was analyzed, it indicated that the breakthrough sulfur capacity decline of sorbent was due to the migration of Zn onto the sorbent surface and Zn accumulated on the surface and vaporized to the exterior from the surface. In the TPO test, the oxidation of Zn was different for 50%Zn/MCM-48 at 700 °C. It revealed that the temperature of regeneration for ZnO sorbent should be higher than 700 °C.

  16. Sulfuric acid functional zirconium (or aluminum) incorporated mesoporous MCM-48 solid acid catalysts for alkylation of phenol with tert-butyl alcohol

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Tingshun, E-mail: tshjiang@mail.ujs.edu.cn; Cheng, Jinlian; Liu, Wangping; Fu, Lie; Zhou, Xuping; Zhao, Qian; Yin, Hengbo

    2014-10-15

    Several zirconium (or aluminum) incorporated mesoporous MCM-48 solid acid catalysts (SO{sub 4}{sup 2−}/Zr-MCM-48 and SO{sub 4}{sup 2−}/Al-MCM-48) were prepared by the impregnation method and their physicochemical properties were characterized by means of XRD, FT-IR, TEM, NH{sub 3}-TPD and N{sub 2} physical adsorption. Also, the catalytic activities of these solid acid catalysts were evaluated by the alkylation of phenol with tert-butyl alcohol. The effect of weight hour space velocity (WHSV), reaction time and reaction temperature on catalytic properties was also studied. The results show that the SO{sub 4}{sup 2−}/Zr-MCM-48 and SO{sub 4}{sup 2−}/Al-MCM-48 still have good mesoporous structure and long range ordering. Compared with the Zr (or Al)–MCM-48 samples, SO{sub 4}{sup 2−}/Zr-MCM-48 and SO{sub 4}{sup 2−}/Al-MCM-48 solid acid catalysts have strong acidity and exhibit high activities in alkylation reaction of phenol with tert-butyl alcohol. The SO{sub 4}{sup 2−}/Zr-MCM-48-25 (molar ratio of Si/Zr=0.04) catalyst was found to be the most promising and gave the highest phenol conversion among all catalysts. A maximum phenol conversion of 91.6% with 4-tert-butyl phenol (4-TBP) selectivity of 81.8% was achieved when the molar ratio of tert-butyl alcohol:phenol is 2:1, reaction time is 2 h, the WHSV is 2 h{sup −1} and the reaction temperature is 140 °C. - Highlights: • Sulfuric acid functional mesoporous solid acid catalysts were prepared via impregnation method. • The alkylation of phenol with tert-butyl alcohol was carried out over these solid acid catalysts. • The catalytic activity of SO{sub 4}{sup 2−}/Zr-MCM-48-25 catalyst is much higher than that of the others. • A maximum phenol conversion of 91.6% was achieved under optimum reaction conditions for SO{sub 4}{sup 2−}/Zr-MCM-48-25.

  17. On the location of iron and aluminium atoms in thermally activated AlMCM-58 and FeMCM-58 zeolites

    Czech Academy of Sciences Publication Activity Database

    Gil, B.; Marszalek, B.; Adamski, A.; Olejniczak, Z.; Kubů, Martin; Čejka, Jiří

    2012-01-01

    Roč. 151, MAR 2012 (2012), s. 339-345 ISSN 1387-1811 R&D Projects: GA ČR GAP106/11/0819; GA ČR GD203/08/H032 Institutional research plan: CEZ:AV0Z40400503 Keywords : MCM-58 * heteroatom location * IR, EPR and NMR spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.365, year: 2012

  18. A Thin Film Nanocomposite Membrane with MCM-41 Silica Nanoparticles for Brackish Water Purification

    Directory of Open Access Journals (Sweden)

    Mohammed Kadhom

    2016-12-01

    Full Text Available Thin film nanocomposite (TFN membranes containing MCM-41 silica nanoparticles (NPs were synthesized by the interfacial polymerization (IP process. An m-phenylenediamine (MPD aqueous solution and an organic phase with trimesoyl chloride (TMC dissolved in isooctane were used in the IP reaction, occurring on a nanoporous polysulfone (PSU support layer. Isooctane was introduced as the organic solvent for TMC in this work due to its intermediate boiling point. MCM-41 silica NPs were loaded in MPD and TMC solutions in separate experiments, in a concentration range from 0 to 0.04 wt %, and the membrane performance was assessed and compared based on salt rejection and water flux. The prepared membranes were characterized via scanning electron microscopy (SEM, transmission electron microscopy (TEM, contact angle measurement, and attenuated total reflection Fourier transform infrared (ATR FT-IR analysis. The results show that adding MCM-41 silica NPs into an MPD solution yields slightly improved and more stable results than adding them to a TMC solution. With 0.02% MCM-41 silica NPs in the MPD solution, the water flux was increased from 44.0 to 64.1 L/m2·h, while the rejection virtually remained the same at 95% (2000 ppm NaCl saline solution, 25 °C, 2068 kPa (300 psi.

  19. A Thin Film Nanocomposite Membrane with MCM-41 Silica Nanoparticles for Brackish Water Purification.

    Science.gov (United States)

    Kadhom, Mohammed; Yin, Jun; Deng, Baolin

    2016-12-06

    Thin film nanocomposite (TFN) membranes containing MCM-41 silica nanoparticles (NPs) were synthesized by the interfacial polymerization (IP) process. An m -phenylenediamine (MPD) aqueous solution and an organic phase with trimesoyl chloride (TMC) dissolved in isooctane were used in the IP reaction, occurring on a nanoporous polysulfone (PSU) support layer. Isooctane was introduced as the organic solvent for TMC in this work due to its intermediate boiling point. MCM-41 silica NPs were loaded in MPD and TMC solutions in separate experiments, in a concentration range from 0 to 0.04 wt %, and the membrane performance was assessed and compared based on salt rejection and water flux. The prepared membranes were characterized via scanning electron microscopy (SEM), transmission electron microscopy (TEM), contact angle measurement, and attenuated total reflection Fourier transform infrared (ATR FT-IR) analysis. The results show that adding MCM-41 silica NPs into an MPD solution yields slightly improved and more stable results than adding them to a TMC solution. With 0.02% MCM-41 silica NPs in the MPD solution, the water flux was increased from 44.0 to 64.1 L/m²·h, while the rejection virtually remained the same at 95% (2000 ppm NaCl saline solution, 25 °C, 2068 kPa (300 psi)).

  20. DEVELOPMENT OF INFORMATION TECHNOLOGY STRATEGIC PLANNING FOR MANUFACTURING INDUSTRY (CASE STUDY: PT MCM

    Directory of Open Access Journals (Sweden)

    Leonardus Hardjo

    2013-10-01

    Full Text Available IT Department in PT MCM has to carry out the duties and functions of developing solution to support the business unit in their operation and gain some benefits which should be obtained by using IT in manufacturing such as increasing efficiency, improving the effectivity in making decision and helping to promote the products. This study aims to design information technology strategic planning in accordance with the strategic plan. The research method is using the IT Strategic Planning framework of Alex Cullen and Marc Cecere. This study uses SWOT and IT Balanced Scorecard to analyze the needs of IT at PT MCM. The results of this study are recommended strategic steps to optimize the implementation of IT in the company to improve the performance from IT division to obtain the benefits by implementing IT in manufacturing and to form IT Blueprint, which is part of the information technology strategic plan in PT MCM.

  1. Fuels by Waste Plastics Using Activated Carbon, MCM-41, HZSM-5 and Their Mixture

    Directory of Open Access Journals (Sweden)

    Miskolczi Norbert

    2016-01-01

    Full Text Available Waste material was pyrolyzed in a horizontal tubular reactor at 530-540°C using different catalysts, such as activated carbon, MCM-41, HZSM-5 and their mixtures. Products were investigated by gas-chromatography, EDXRFS and standardized methods. Catalysts significantly affected the yields of volatiles; e.g. HZSM-5 catalyst increased especially the yield of gaseous hydrocarbons, while MCM-41 catalyst was responsible for increasing the pyrolysis oil yield. Synergistic effects were found using mixtures of different catalysts. Furthermore the catalysts modified the main carbon frame of the products. Pyrolysis oil obtained over HZSM-5 catalyst contained large amounts of aromatics, while MCM-41 catalyst mainly isomerized the carbon frame. Regarding contaminants it was concluded, that the sulphur content could be significantly decreased by activated carbon, however it had only a slight effect to the other properties of the products.

  2. Expression of minichromosome maintenance genes in renal cell carcinoma

    Directory of Open Access Journals (Sweden)

    Zhong HB

    2017-11-01

    disease-free survival. Importantly, we also demonstrated that overexpression of MCM genes is an independent predictor for survival in RCC patients. Our results suggest that MCM2–7 genes may be an important prognostic marker for patients with RCC. Keywords: MCM proteins, kidney cancer, prognostic marker, metastases, survival

  3. Effect of growth factors (BMP-4/7 & bFGF on proliferation & osteogenic differentiation of bone marrow stromal cells

    Directory of Open Access Journals (Sweden)

    Shaohui Yuan

    2013-01-01

    Full Text Available Background & objectives: BMP (bone morphogenetic protein-4/7 and bFGF (basic fibroblast growth factor significantly promote the osteogenic activity and the proliferation of rabbit BMSCs (bone marrow stromal cells, respectively. However, their synergistic effects on the proliferation and the differentiation of BMSCs remain unclear. In the present study, the effects of bFGF and BMP-4/7 were investigated on the proliferation and the differentiation of rat BMSCs in vitro. Methods: BMSCs were isolated from New Zealand white rabbits and cultured to the third passage. The samples were divided into five groups according to the material implanted: (A 80 ng/ml BMP-4/7; (B 80 ng/ml bFGF; (C 30 ng/ml BMP-4/7 and 30 ng/ml bFGF; (D 50 ng/ml BMP-4/7 and 50 ng/ml bFGF; and (E 80 ng/ml BMP-4/7 and 80 ng/ml bFGF. Cell proliferation was analyzed using methyl thiazolyl tetrazolium (MTT assay. Alkaline phosphatase activity and osteocalcin (OC dynamics were also measured. Results: BMP-4/7 alone significantly (P<0.05 promoted the proliferation of BMSCs. At the same time, it also promoted or inhibited the osteogenic differentiation of BMSCs. The synergistic effects of BMP-4/7 and bFGF significantly promoted both the proliferation and the osteogenic differentiation of BMSCs. The treatment of the synergistic effects was dose and time dependent. Interpretation & conclusions: A rational combination of BMP-4/7 and bFGF can promote the proliferation and the osteogenic differentiation of BMSCs. In addition, the synergistic functions are effective.

  4. Enhanced adsorptive and photocatalytic achievements in removal of methylene blue by incorporating tungstophosphoric acid-TiO2 into MCM-41

    International Nuclear Information System (INIS)

    Zanjanchi, M.A.; Golmojdeh, H.; Arvand, M.

    2009-01-01

    The use of titania-dispersed materials in photocatalytic processes has been proposed as an alternative to the conventional bare TiO 2 , in order to modify the surface area and activity of the catalyst. A homogeneously dispersed Keggin unit into TiO 2 was synthesized using tungstophosphoric acid (TPA) and titanium tetraisopropoxide. This compound was then loaded into MCM-41 by dispersing it in a suspension containing the mesoporous phase. Two other titanium-containing MCM-41 catalysts, Ti-MCM-41 and TiO 2 /MCM-41 were also prepared using isomorphous substitution synthesis method and impregnation method, respectively, for the sake of comparison. The prepared photocatalysts were characterized by X-ray diffraction (XRD), nitrogen physisorption (BET) and chemical analysis. The catalysts were used to study degradation of methylene blue (MB) in aqueous solution. XRD result shows a pure anatase crystalline phase for TPA-containing TiO 2 indicating that there is good molecular distribution of tungstophosphoric acid into TiO 2 structure. Supported TPA-TiO 2 into MCM-41 shows both TPA-TiO 2 and MCM-41 characteristic X-ray reflections in the high-angle and low-angle parts of the XRD patterns, respectively. The experimental results show that adsorption is a major constituent in the elimination of MB from the dye solutions by the TPA-containing materials. Exploitation of both adsorption and photocatalytic processes speeds up the removal of the dye using the TPA-TiO 2 -loaded MCM-41 photocatalyst. The elimination of MB is completed within 15 min for a 30 mg l -1 MB solution containing a catalyst dose of 100 mg/100 ml. The efficiencies of the other photocatalysts such as commercial TiO 2 , Ti-MCM-41, TiO 2 /MCM-41 and TPA-TiO 2 for adsorption and degradation of MB were also studied and compared with that of the prepared catalyst.

  5. Eco-friendly synthesis for MCM-41 nanoporous materials using the non-reacted reagents in mother liquor.

    Science.gov (United States)

    Ng, Eng-Poh; Goh, Jia-Yi; Ling, Tau Chuan; Mukti, Rino R

    2013-03-04

    Nanoporous materials such as Mobil composite material number 41 (MCM-41) are attractive for applications such as catalysis, adsorption, supports, and carriers. Green synthesis of MCM-41 is particularly appealing because the chemical reagents are useful and valuable. We report on the eco-friendly synthesis of MCM-41 nanoporous materials via multi-cycle approach by re-using the non-reacted reagents in supernatant as mother liquor after separating the solid product. This approach was achieved via minimal requirement of chemical compensation where additional fresh reactants were added into the mother liquor followed by pH adjustment after each cycle of synthesis. The solid product of each successive batch was collected and characterized while the non-reacted reagents in supernatant can be recovered and re-used to produce subsequent cycle of MCM-41. The multi-cycle synthesis is demonstrated up to three times in this research. This approach suggests a low cost and eco-friendly synthesis of nanoporous material since less waste is discarded after the product has been collected, and in addition, product yield can be maintained at the high level.

  6. Coordination and Oxidation States of Iron Incorporated in Mesoporous MCM41

    International Nuclear Information System (INIS)

    Lazar, K.; Pal-Borbely, G.; Szegedi, A.; Beyer, H. K.

    2002-01-01

    Mesoporous Fe-MCM41 samples (Si/Fe=25) were synthesized and characterized under evacuation and reducing/oxidizing treatments by in situ FTIR and Moessbauer spectroscopies. Both Fe(II) and Fe(III) located in low coordination states in top layers of pore walls exhibit Lewis acidity and may participate in Fe(III) ↔ Fe(II) processes at low temperatures (570 K). Furthermore, Fe(III) ↔ Fe(II) cycles can be achieved and repeated with participation of the full amount of iron at higher temperatures (670 K). The accompanying formation of oxygen vacancies and restoration of the structure in the reverse process does not result in extended damages; the MCM41 structure retains its stability under the conditions applied.

  7. Comprehensive Characterization of Minichromosome Maintenance Complex (MCM) Protein Interactions Using Affinity and Proximity Purifications Coupled to Mass Spectrometry.

    Science.gov (United States)

    Dubois, Marie-Line; Bastin, Charlotte; Lévesque, Dominique; Boisvert, François-Michel

    2016-09-02

    The extensive identification of protein-protein interactions under different conditions is an important challenge to understand the cellular functions of proteins. Here we use and compare different approaches including affinity purification and purification by proximity coupled to mass spectrometry to identify protein complexes. We explore the complete interactome of the minichromosome maintenance (MCM) complex by using both approaches for all of the different MCM proteins. Overall, our analysis identified unique and shared interaction partners and proteins enriched for distinct biological processes including DNA replication, DNA repair, and cell cycle regulation. Furthermore, we mapped the changes in protein interactions of the MCM complex in response to DNA damage, identifying a new role for this complex in DNA repair. In summary, we demonstrate the complementarity of these approaches for the characterization of protein interactions within the MCM complex.

  8. THE THIOREDOXIN SYSTEM IN REGULATING MCF-7 CELL PROLIFERATION UNDER REDOX STATUS MODULATION

    Directory of Open Access Journals (Sweden)

    E. A. Stepovaya

    2016-01-01

    Full Text Available Introduction. Despite the available data on tumor cell functioning under the conditions of free radical-mediated oxidation, the mechanisms of redox regulation, cell proliferation management and apoptosis avoidance remain understudied.The objective of the study was to identify the role of the thioredoxin system in regulating MCF-7 breast cancer cell proliferation under redox status modulation with 1.4-dithioerythritol.Material and methods. The studies were conducted on the MCF-7 breast cancer cell line, grown in adherent cell culture. Cell redox status was modulated with5 mM N-ethylmaleimide – an SH group and peptide inhibitor and5 mM 1.4-dithioerythritol – a thiol group protector. The cell cycle was evaluated by flow cytometry, the same technique was used to measure the reactive oxygen species concentration. The levels of reduced and oxidized glutathione and the activity of thioredoxin reductase were identified by spectrophotometry. The intracellular concentrations of thioredoxin, cyclin E and cyclin-dependent kinase 2 were determined by Western blot analysis.Results and discussion. The essential role of the thioredoxin system in regulating MCF-7 breast cancer cell proliferation was exhibited. S-phase arrest under the effect of N-ethylmaleimide and G0/G1-phase arrest under the effect of 1.4-dithioerythritol are associated with the changes in the activity of redox-sensitive protein complexes (cyclins and cyclin-dependent kinases that regulate cell proliferation.Conclusion. Redoxdependent modulation of proliferation regulating intracellular protein activity occurs due to the thioredoxin system. This is a promising research area for seeking molecular targets of breast cell malignization. 

  9. Improvement of surface acidity and structural regularity of Zr-modified mesoporous MCM-41

    Energy Technology Data Exchange (ETDEWEB)

    Chen, L.F. [Departamento de Ciencias Basicas, Universidad Autonoma Metropolitana-A, Av. San Pablo 180, Col. Reynosa-Tamaulipas, 02200 Mexico D.F. (Mexico)]. E-mail: chenlf2001@yahoo.com; Norena, L.E. [Departamento de Ciencias Basicas, Universidad Autonoma Metropolitana-A, Av. San Pablo 180, Col. Reynosa-Tamaulipas, 02200 Mexico D.F. (Mexico); Navarrete, J. [Grupo de Molecular Ingenieria, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas 152, 07730 Mexico D.F. (Mexico); Wang, J.A. [Laboratorio de Catalisis y Materiales, SEPI-ESIQIE, Instituto Politecnico Nacional, Av. Politecnico S/N, Col. Zacatenco, 07738 Mexico D.F. (Mexico)

    2006-06-10

    This work reports the synthesis and surface characterization of a Zr-modified mesoporous MCM-41 solid with an ordered hexagonal arrangement, prepared through a templated synthesis route, using cetyltrimethylammonium chloride as the template. The surface features, crystalline structure, textural properties and surface acidity of the materials were characterized by in situ Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), N{sub 2} physisorption isotherms, {sup 29}Si MAS-NMR and in situ FT-IR of pyridine adsorption. It is evident that the surfactant cations inserted into the network of the solids during the preparation could be removed by calcination of the sample above 500 deg. C. The resultant material showed a large surface area of 680.6 m{sup 2} g{sup -1} with a uniform pore diameter distribution in a very narrow range centered at approximately 2.5 nm. Zirconium incorporation into the Si-MCM-41 framework, confirmed by {sup 29}Si MAS-NMR analysis, increased not only the wall thickness of the mesopores but also the long-range order of the periodically hexagonal structure. Both, Lewis and Broensted acid sites, were formed on the surface of the Zr-modified MCM-41 solid. Compared to Si-MCM-41 on which only very weak Lewis acid sites were formed, the densities of both Lewis and Broensted acid sites and the strength of the acidity on the Zr-modified sample were significantly increased, indicating that the incorporation of zirconium greatly enhances the acidity of the material.

  10. Solid-state (49/47)Ti NMR of titanium-based MCM-41 hybrid materials.

    Science.gov (United States)

    Ballesteros, Ruth; Fajardo, Mariano; Sierra, Isabel; Force, Carmen; del Hierro, Isabel

    2009-11-03

    Titanium solid-state NMR spectroscopy data for a series of organic-inorganic titanium MCM-41 based materials have been collected. These materials have been synthesized by first modifying the mesoporous silica MCM-41 in one step with a mixture of silanes: a triazine propyl triethoxysilane acting as functional linker and methyltrimethoxysilane or hexamethyldisilizane as capped agents to mask the remaining silanol groups. Second, the appropiate titanium precursor Ti(OPr(i))(4), [{Ti(OPr(i))(3)(OMent)}(2)] (OMent = 1R,2S,5R-(-)-menthoxo), Ti(OPr(i))(4), or [Ti(eta(5)-C(5)HMe(4))Cl(3)], has been immobilized by reaction with the modified MCM-41. Finally, after Ti(OPr(i))(4) immobilization onto the organomodified support the reaction with the chiral (+)-diethyl-l-tartrate was accomplished. The materials without functional linker have been also prepared by reaction in one step of the capped agent and the titanium precursor with the mesoporous silica. Relevant correlations of titanium NMR resonance chemical shifts and line widths can be inferred depending on different factors. The immobilization procedure used to prepare titanium-based MCM-41 hybrid materials and the choice of the silylating reagents employed to mask the silanol groups present on the silica surfaces produce significant differences in the Ti NMR spectra. Furthermore, depending on the electronic and sterical influence of the substituents directly attached to the titanium center, chemical shifts and line widths are modified providing novel information about titanium structure.

  11. Thermal and hydrothermal stability of ZrMCM-41 mesoporous ...

    Indian Academy of Sciences (India)

    Administrator

    The mesoporous structure of the ZrMCM-41 mesoporous molecular sieve still retains after calcination at 750°C for 3 h or ... adsorption, sensor and petrochemical industry. 2–5. However, the ... the pH value of the mixed solution was adjusted to.

  12. Homeobox A7 increases cell proliferation by up-regulation of epidermal growth factor receptor expression in human granulosa cells

    Directory of Open Access Journals (Sweden)

    Yanase Toshihiko

    2010-06-01

    Full Text Available Abstract Background Homeobox (HOX genes encode transcription factors, which regulate cell proliferation, differentiation, adhesion, and migration. The deregulation of HOX genes is frequently associated with human reproductive system disorders. However, knowledge regarding the role of HOX genes in human granulosa cells is limited. Methods To determine the role of HOXA7 in the regulation and associated mechanisms of cell proliferation in human granulosa cells, HOXA7 and epidermal growth factor receptor (EGFR expressions were examined in primary granulosa cells (hGCs, an immortalized human granulosa cell line, SVOG, and a granulosa tumor cell line, KGN, by real-time PCR and Western blotting. To manipulate the expression of HOXA7, the HOXA7 specific siRNA was used to knockdown HOXA7 in KGN. Conversely, HOXA7 was overexpressed in SVOG by transfection with the pcDNA3.1-HOAX7 vector. Cell proliferation was measured by the MTT assay. Results Our results show that HOXA7 and EGFR were overexpressed in KGN cells compared to hGCs and SVOG cells. Knockdown of HOXA7 in KGN cells significantly decreased cell proliferation and EGFR expression. Overexpression of HOXA7 in SVOG cells significantly promoted cell growth and EGFR expression. Moreover, the EGF-induced KGN proliferation was abrogated, and the activation of downstream signaling was diminished when HOXA7 was knocked down. Overexpression of HOXA7 in SVOG cells had an opposite effect. Conclusions Our present study reveals a novel mechanistic role for HOXA7 in modulating granulosa cell proliferation via the regulation of EGFR. This finding contributes to the knowledge of the pro-proliferation effect of HOXA7 in granulosa cell growth and differentiation.

  13. Influence of aluminum addition in the framework of MCM-41 mesoporous molecular sieve synthesized by non-hydrothermal method in an alkali-free system

    International Nuclear Information System (INIS)

    La-Salvia, Nathália; Lovón-Quintana, Juan José; Lovón, Adriana Siviero Pagani; Valença, Gustavo Paim

    2017-01-01

    Purely siliceous MCM-41 and Al-containing MCM-41 (Al-MCM-41) mesoporous materials were synthesized by non-hydrothermal method in alkali-free ions medium at room temperature and short reaction times. Under these synthesis conditions, it was also investigated the influence of Al incorporation in the crystal structure of MCM-41. The solids were characterized by ICP-OES, AAS, N 2 adsorption at 77 K, XRD, TEM, NH3 -TPD, 27 Al and 29 Si-MAS-NMR, FT-IR and TGA. The resulting mesoporous materials showed a well-defined hexagonally ordered pore geometry maintaining a uniform and unimodal pore size distribution with high specific surface areas (1000-1400 m 2 g -1 ). The Al +3 ions were introduced successfully in the structure of the purely siliceous MCM-41 expanding the unit cell parameter and forming four-coordinated Al species, and in a less extent, forming six-coordinated Al species. In addition, the surface acidity of the MCM-41 increased with Al loading. Contrary, the presence of Al in the MCM-41 mesoporous structure resulted in a decrease of the crystallinity and specific surface area possibly due to the presence of Al species in highly distorted tetrahedral structures and Al extra-framework or amorphous alumina occluded in the pores. The MCM-41 type mesoporous materials obtained in this work show similar characteristics of those synthesized by conventional hydrothermal methods. (author)

  14. Phosphorylation of Minichromosome Maintenance 3 (MCM3) by Checkpoint Kinase 1 (Chk1) Negatively Regulates DNA Replication and Checkpoint Activation.

    Science.gov (United States)

    Han, Xiangzi; Mayca Pozo, Franklin; Wisotsky, Jacob N; Wang, Benlian; Jacobberger, James W; Zhang, Youwei

    2015-05-08

    Mechanisms controlling DNA replication and replication checkpoint are critical for the maintenance of genome stability and the prevention or treatment of human cancers. Checkpoint kinase 1 (Chk1) is a key effector protein kinase that regulates the DNA damage response and replication checkpoint. The heterohexameric minichromosome maintenance (MCM) complex is the core component of mammalian DNA helicase and has been implicated in replication checkpoint activation. Here we report that Chk1 phosphorylates the MCM3 subunit of the MCM complex at Ser-205 under normal growth conditions. Mutating the Ser-205 of MCM3 to Ala increased the length of DNA replication track and shortened the S phase duration, indicating that Ser-205 phosphorylation negatively controls normal DNA replication. Upon replicative stress treatment, the inhibitory phosphorylation of MCM3 at Ser-205 was reduced, and this reduction was accompanied with the generation of single strand DNA, the key platform for ataxia telangiectasia mutated and Rad3-related (ATR) activation. As a result, the replication checkpoint is activated. Together, these data provide significant insights into the regulation of both normal DNA replication and replication checkpoint activation through the novel phosphorylation of MCM3 by Chk1. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  15. Characterization of 12-molybdophosphoric acid supported on mesoporous silica MCM-41 and its catalytic performance in the synthesis of hydroquinone diacetate

    International Nuclear Information System (INIS)

    Ahmed, Awad I.; Samra, S.E.; El-Hakam, S.A.; Khder, A.S.; El-Shenawy, H.Z.; El-Yazeed, W.S. Abo

    2013-01-01

    12-molybdophosphoric acid (PMA) was supported on mesoporous molecular sieves MCM-41 by impregnation of 12-molybdophosphoric acid followed by calcination. The nanochannels of MCM-41 provide a large surface area for the solid state dispersion of 12-molybdophosphoric acid. The samples have been characterized by N 2 adsorption–desorption at −196 °C, transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), and FT-IR measurements. The acidity and catalytic activity have been, respectively, examined by nonaqueous titration of n-butylamine in acetonitrile and synthesis of hydroquinone diacetate. The results showed that ordered hexagonal pore structure was observed in the synthesized MCM-41. Also the results indicate that PMA are highly dispersed on mesoporous silica MCM-41 spherical nanoparticles while PMA retains its Keggin structure. On the other hand, with increasing the introduced PMA amount, the specific surface area decreases, and the mesoporous ordering of the samples become poor. Both the surface acidity and the catalytic activity sharply increase with the modification of MCM-41 by PMA but decrease by increasing the calcination temperature. The sample with 55 wt% PMA/MCM-41 calcined at 350 °C shows the highest acidity and catalytic activity.

  16. Magnetic properties of iron loaded MCM-48 molecular sieves

    Energy Technology Data Exchange (ETDEWEB)

    Elias, Veronica R. [Centro de Investigacion y Tecnologia Quimica, Universidad Tecnologica Nacional, Facultad Regional Cordoba. Cordoba (Argentina); CONICET (Argentina); Oliva, Marcos I. [Facultad de Matematica, Astronomia y Fisica, Universidad Nacional de Cordoba, Cordoba (Argentina); IFEG-CONICET (Argentina); Vaschetto, Eliana G. [Centro de Investigacion y Tecnologia Quimica, Universidad Tecnologica Nacional, Facultad Regional Cordoba. Cordoba (Argentina); Urreta, Silvia E., E-mail: urreta@famaf.unc.edu.a [Facultad de Matematica, Astronomia y Fisica, Universidad Nacional de Cordoba, Cordoba (Argentina); Eimer, Griselda A. [Centro de Investigacion y Tecnologia Quimica, Universidad Tecnologica Nacional, Facultad Regional Cordoba. Cordoba (Argentina); CONICET (Argentina); Silvetti, Silvia P. [Facultad de Matematica, Astronomia y Fisica, Universidad Nacional de Cordoba, Cordoba (Argentina)

    2010-11-15

    Mesoporous molecular sieves of MCM-48 type were loaded with iron by the wet impregnation method, using Fe(III) nitrate or Fe(II) sulfate aqueous solutions as Fe sources, to obtain a magnetic porous composite. The iron loaded materials were characterized by XRD, N{sub 2} adsorption and DRUV-vis and compared with the Si-MCM-48 host. Their magnetic properties were studied by measuring the hysteresis loops up to 1.5 T at different temperatures (5-300 K) and by magnetization vs. temperature curves following the conventional zero field cooling (ZFC) and field cooling (FC) protocols. Materials with high structure regularity and surface area are obtained, which exhibit a mixed paramagnetic and superparamagnetic behavior, arising in isolated iron ions inserted in the host framework, and in small iron oxide clusters or nanoparticles forming inside the pores, respectively. Larger hematite particles (8-13 nm) grown on the external surface provide a quite small ferromagnetic contribution to the hysteresis loop.

  17. Magnetic properties of iron loaded MCM-48 molecular sieves

    International Nuclear Information System (INIS)

    Elias, Veronica R.; Oliva, Marcos I.; Vaschetto, Eliana G.; Urreta, Silvia E.; Eimer, Griselda A.; Silvetti, Silvia P.

    2010-01-01

    Mesoporous molecular sieves of MCM-48 type were loaded with iron by the wet impregnation method, using Fe(III) nitrate or Fe(II) sulfate aqueous solutions as Fe sources, to obtain a magnetic porous composite. The iron loaded materials were characterized by XRD, N 2 adsorption and DRUV-vis and compared with the Si-MCM-48 host. Their magnetic properties were studied by measuring the hysteresis loops up to 1.5 T at different temperatures (5-300 K) and by magnetization vs. temperature curves following the conventional zero field cooling (ZFC) and field cooling (FC) protocols. Materials with high structure regularity and surface area are obtained, which exhibit a mixed paramagnetic and superparamagnetic behavior, arising in isolated iron ions inserted in the host framework, and in small iron oxide clusters or nanoparticles forming inside the pores, respectively. Larger hematite particles (8-13 nm) grown on the external surface provide a quite small ferromagnetic contribution to the hysteresis loop.

  18. Butanol Dehydration over V₂O₅-TiO₂/MCM-41 Catalysts Prepared via Liquid Phase Atomic Layer Deposition.

    Science.gov (United States)

    Choi, Hyeonhee; Bae, Jung-Hyun; Kim, Do Heui; Park, Young-Kwon; Jeon, Jong-Ki

    2013-04-29

    MCM-41 was used as a support and, by using atomic layer deposition (ALD) in the liquid phase, a catalyst was prepared by consecutively loading titanium oxide and vanadium oxide to the support. This research analyzes the effect of the loading amount of vanadium oxide on the acidic characteristics and catalytic performance in the dehydration of butanol. The physical and chemical characteristics of the TiO₂-V₂O₅/MCM-41 catalysts were analyzed using XRF, BET, NH₃-TPD, XRD, Py-IR, and XPS. The dehydration reaction of butanol was performed in a fixed bed reactor. For the samples with vanadium oxide loaded to TiO₂/MCM-41 sample using the liquid phase ALD method, it was possible to increase the loading amount until the amount of vanadium oxide reached 12.1 wt %. It was confirmed that the structural properties of the mesoporous silica were retained well after titanium oxide and vanadium loading. The NH₃-TPD and Py-IR results indicated that weak acid sites were produced over the TiO₂/MCM-41 samples, which is attributed to the generation of Lewis acid sites. The highest activity of the V₂O₅(12.1)-TiO₂/MCM-41 catalyst in 2-butanol dehydration is ascribed to it having the highest number of Lewis acid sites, as well as the highest vanadium dispersion.

  19. Synthesis and characterization of Co-Fe Prussian blue nanoparticles within MCM-41

    International Nuclear Information System (INIS)

    Vien Vo; Nguyen Van Minh; Lee, Hyung Ik; Kim, Ji Man; Kim, Youngmee; Kim, Sung Jin

    2009-01-01

    A Prussian blue analogue, K 0.84 Co 1.08 [Fe(CN) 6 ] is prepared by reaction between [Fe(CN) 6 ] 3- in aqueous solution and ion-exchanged Co 2+ in the channels of MCM-41. Powder X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, nitrogen adsorption/desorption isotherms, diffuse reflectance UV-vis absorption spectroscopy and magnetic measurements were employed to characterize the product. The results show that the Prussian blue analogue is in nanoparticles within the channels and the hexagonal phase of MCM-41 remains intact during the reactions. A particle size effect on optical and magnetic properties of the nanoparticles was observed

  20. Preparation of hierarchical micro-mesoporous aluminosilicate composites by simple Y zeolite/MCM-48 silica assembly

    Energy Technology Data Exchange (ETDEWEB)

    Enterría, Marina, E-mail: marina@incar.csic.es; Suárez-García, Fabián; Martínez-Alonso, Amelia; Tascón, Juan M.D.

    2014-01-15

    Highlights: • Hierarchical micro-mesoporous aluminosilicates were synthesized. • Y zeolite core/MCM-48 silica shell structures were obtained. • Y zeolite favors the formation of the mesostructure. • Porosity and structure can be varied by modifying the preparation variables. • Duration of the hydrothermal step has a great effect on the materials properties. -- Abstract: A simple procedure to obtain hierarchical micro-mesoporous aluminosilicate composites was developed by growing MCM-48 silica over commercial Y zeolite. The obtained hierarchical composites have a microporous core and a mesoporous shell. The process consists in assembling dispersed Y zeolite with a mesoporous silica phase that is formed “in situ” by “soft-templating” with cetryltrimethylammonium bromide (CTAB) as surfactant. The Y zeolite/MCM-48 silica ratio and aging time were varied to study their effects on the final porosity and structure of the hierarchical composites. The pore textural and structural characteristics of the composites did not match those of the corresponding Y zeolite/MCM-48 silica physical mixtures. This implies that the synthesized composites integrate micropores and mesopores in the same bulk. The obtained composites exhibited micropore and mesopore volumes ranging between 0.15–0.31 and 0.30–0.51 cm{sup 3}/g, respectively. X-ray diffraction and N{sub 2} adsorption results revealed that the presence of zeolite in the reaction medium favors the formation of mesopores in the obtained materials, especially for short hydrothermal treatments. TEM results showed that the obtained adsorbents are constituted by an integrated micro-mesoporous bimodal system in which Y zeolite is surrounded by a thin cover of MCM-48 silica.

  1. Preparation of hierarchical micro-mesoporous aluminosilicate composites by simple Y zeolite/MCM-48 silica assembly

    International Nuclear Information System (INIS)

    Enterría, Marina; Suárez-García, Fabián; Martínez-Alonso, Amelia; Tascón, Juan M.D.

    2014-01-01

    Highlights: • Hierarchical micro-mesoporous aluminosilicates were synthesized. • Y zeolite core/MCM-48 silica shell structures were obtained. • Y zeolite favors the formation of the mesostructure. • Porosity and structure can be varied by modifying the preparation variables. • Duration of the hydrothermal step has a great effect on the materials properties. -- Abstract: A simple procedure to obtain hierarchical micro-mesoporous aluminosilicate composites was developed by growing MCM-48 silica over commercial Y zeolite. The obtained hierarchical composites have a microporous core and a mesoporous shell. The process consists in assembling dispersed Y zeolite with a mesoporous silica phase that is formed “in situ” by “soft-templating” with cetryltrimethylammonium bromide (CTAB) as surfactant. The Y zeolite/MCM-48 silica ratio and aging time were varied to study their effects on the final porosity and structure of the hierarchical composites. The pore textural and structural characteristics of the composites did not match those of the corresponding Y zeolite/MCM-48 silica physical mixtures. This implies that the synthesized composites integrate micropores and mesopores in the same bulk. The obtained composites exhibited micropore and mesopore volumes ranging between 0.15–0.31 and 0.30–0.51 cm 3 /g, respectively. X-ray diffraction and N 2 adsorption results revealed that the presence of zeolite in the reaction medium favors the formation of mesopores in the obtained materials, especially for short hydrothermal treatments. TEM results showed that the obtained adsorbents are constituted by an integrated micro-mesoporous bimodal system in which Y zeolite is surrounded by a thin cover of MCM-48 silica

  2. Efficient Hydrogenolysis of Guaiacol over Highly Dispersed Ni/MCM-41 Catalyst Combined with HZSM-5

    Directory of Open Access Journals (Sweden)

    Songbai Qiu

    2016-09-01

    Full Text Available A series of MCM-41 supported Ni catalysts with high metal dispersion was successfully synthesized by simple co-impregnation using proper ethylene glycol (EG. The acquired Ni-based catalysts performed the outstanding hydrogenolysis activity of guaiacol. The effects of the synthesis parameters including drying temperature, calcination temperature, and metal loading on the physical properties of NiO nanoparticles were investigated through the use of X-ray diffraction (XRD. The drying temperature was found to significantly influence the particle sizes of NiO supported on MCM-41, but the calcination temperature and metal loading had less influence. Interestingly, the small particle size (≤3.3 nm and the high dispersion of NiO particles were also obtained for co-impregnation on the mixed support (MCM-41:HZSM-5 = 1:1, similar to that on the single MCM-41 support, leading to excellent hydrogenation activity at low temperature. The guaiacol conversion could reach 97.9% at 150 °C, and the catalytic activity was comparative with that of noble metal catalysts. The hydrodeoxygenation (HDO performance was also promoted by the introduction of acidic HZSM-5 zeolite and an 84.1% yield of cyclohexane at 240 °C was achieved. These findings demonstrate potential applications for the future in promoting and improving industrial catalyst performance.

  3. Enhancement of Catalytic Performance of MCM-41 Synthesized with Rice Husk Silica by Addition of Titanium Dioxide for Photodegradation of Alachlor

    Directory of Open Access Journals (Sweden)

    Surachai Artkla

    2009-01-01

    Full Text Available Photocatalytic degradation of alachlor, a herbicide, in water on both bare TiO2 and TiO2 supported on mesoporous material, marked as TiO2/RH-MCM-41 were studied. The RH-MCM-41 support was synthesized from rice husk silica and other reagents by hydrothermal method. The required amount of titanium precursor (TiO2 P25 Degussa to give 10-60% was mixed with RH-MCM-41 and calcined at 300 °C for 6 h. The catalytic activities of TiO2 and TiO2/RH-MCM-41 for alachlor degradation were performed under UV radiation with wavelength of 300 nm. The ratio of catalyst weight to volume of alachlor solution was 1 g/L and all products were characterized by high performance liquid chromatograph. The reaction equilibrium was established in 30 min. in deionized water without adjusting the solution pH. The TiO2/RH-MCM-41 could adsorb alachlor more than the bare TiO2 (namely, 17% vs. 5% and the photocatalytic activity of alachlor degration on all TiO2/RH-MCM-41s was higher than that on the bare TiO2. By comparison per weight of TiO2, the 10%TiO2/RH-MCM-41 gave the highest alachlor conversion of 100% after 20 min. while 1% bare TiO2 showed conversion of 95%.

  4. Influence of incorporation method of sulfated zirconia in MCM-41 molecular sieve; Influencia do metodo de incorporacao da zirconia sulfatada na peneira molecular MCM-41

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, C.E.; Santos, J.S.B.; Cavalcante, J.N.A.; Andrade, M.R.A.; Sousa, B.V., E-mail: eduardopereira.eq@gmail.com [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Centro de Ciencia e Tecnologia

    2016-07-01

    Sulfated metal oxides and sulfated zirconia have attracted great attention in recent years due to its high catalytic activity. The sulfated zirconia has the function of assigning the acidic material, through the formation of Bronsted acids and Lewis sites. The incorporation of sulfated zirconia in MCM-41 molecular sieve was carried out through the techniques: dry and wet. The wet process involves the use of an excess of solution on the volume of the support pores. Therefore, the concentration of the metal precursor on the support depends on the solution concentration and the pore volume of the support. In the process of incorporating by dry, the volume of the solution containing the precursor does not exceed the pore volume of the support. After either procedure, the impregnated support must be dried in order to allow the precursor compound can be converted into a catalytically active phase. This study aims to evaluate two methods of incorporation of sulfated zirconia in the mesoporous molecular sieve MCM-41. The process of merger took for wet and dry impregnation. Through the XRD patterns it was possible to identify the presence of the hexagonal structure of the molecular sieve, as well as the tetragonal and monoclinic phases of zirconia. From the spectroscopic analysis in the infrared region to the method the wet, it was possible to identify the vibrational frequencies related to the merger of sulfated zirconia in the MCM-41 structure of the molecular sieve. (author)

  5. Influence of aluminum addition in the framework of MCM-41 mesoporous molecular sieve synthesized by non-hydrothermal method in an alkali-free system

    Energy Technology Data Exchange (ETDEWEB)

    La-Salvia, Nathália; Lovón-Quintana, Juan José; Lovón, Adriana Siviero Pagani; Valença, Gustavo Paim, E-mail: nathalialasalvia@gmail.com [Laboratório para o Estudo de Processos de Adsorção e Catálise - LEPAC, Faculdade de Engenharia Química, Universidade Estadual de Campinas - UNICAMP, Campinas, SP (Brazil)

    2017-11-15

    Purely siliceous MCM-41 and Al-containing MCM-41 (Al-MCM-41) mesoporous materials were synthesized by non-hydrothermal method in alkali-free ions medium at room temperature and short reaction times. Under these synthesis conditions, it was also investigated the influence of Al incorporation in the crystal structure of MCM-41. The solids were characterized by ICP-OES, AAS, N{sub 2} adsorption at 77 K, XRD, TEM, NH3 -TPD, {sup 27}Al and {sup 29}Si-MAS-NMR, FT-IR and TGA. The resulting mesoporous materials showed a well-defined hexagonally ordered pore geometry maintaining a uniform and unimodal pore size distribution with high specific surface areas (1000-1400 m{sup 2} g{sup -1}). The Al{sup +3} ions were introduced successfully in the structure of the purely siliceous MCM-41 expanding the unit cell parameter and forming four-coordinated Al species, and in a less extent, forming six-coordinated Al species. In addition, the surface acidity of the MCM-41 increased with Al loading. Contrary, the presence of Al in the MCM-41 mesoporous structure resulted in a decrease of the crystallinity and specific surface area possibly due to the presence of Al species in highly distorted tetrahedral structures and Al extra-framework or amorphous alumina occluded in the pores. The MCM-41 type mesoporous materials obtained in this work show similar characteristics of those synthesized by conventional hydrothermal methods. (author)

  6. A Novel Silicon Micromachined Integrated MCM Thermal Management System

    Science.gov (United States)

    Kazmierczak, M. J.; Henderson, H. T.; Gerner, F. M.

    1997-01-01

    "Micromachining" is a chemical means of etching three-dimensional structures, typically in single- crystalline silicon. These techniques are leading toward what is coming to be referred to as MEMS (Micro Electro Mechanical Systems), where in addition to the ordinary two-dimensional (planar) microelectronics, it is possible to build three-dimensional n-ticromotors, electrically- actuated raicrovalves, hydraulic systems and much more on the same microchip. These techniques become possible because of differential etching rates of various crystallographic planes and materials used for semiconductor n-ticrofabfication. The University of Cincinnati group in collaboration with Karl Baker at NASA Lewis were the first to form micro heat pipes in silicon by the above techniques. Current work now in progress using MEMS technology is now directed towards the development of the next generation in MCM (Multi Chip Module) packaging. Here we propose to develop a complete electronic thermal management system which will allow densifica6on in chip stacking by perhaps two orders of magnitude. Furthermore the proposed technique will allow ordinary conu-nercial integrated chips to be utilized. Basically, the new technique involves etching square holes into a silicon substrate and then inserting and bonding commercially available integrated chips into these holes. For example, over a 100 1/4 in. by 1 /4 in. integrated chips can be placed on a 4 in. by 4 in. silicon substrate to form a Multi-Chip Module (MCM). Placing these MCM's in-line within an integrated rack then allows for three-diniensional stacking. Increased miniaturization of microelectronic circuits will lead to very high local heat fluxes. A high performance thermal management system will be specifically designed to remove the generated energy. More specifically, a compact heat exchanger with milli / microchannels will be developed and tested to remove the heat through the back side of this MCM assembly for moderate and high

  7. New MCM8 mutation associated with premature ovarian insufficiency and chromosomal instability in a highly consanguineous Tunisian family.

    Science.gov (United States)

    Bouali, Nouha; Francou, Bruno; Bouligand, Jérôme; Imanci, Dilek; Dimassi, Sarra; Tosca, Lucie; Zaouali, Monia; Mougou, Soumaya; Young, Jacques; Saad, Ali; Guiochon-Mantel, Anne

    2017-10-01

    To identify the gene(s) involved in the etiology of premature ovarian insufficiency in a highly consanguineous Tunisian family. Genetic analysis of a large consanguineous family with several affected siblings. University hospital-based cytogenetics and molecular genetics laboratories. A highly consanguineous Tunisian family with several affected siblings born to healthy second-degree cousins. None. Targeted exome sequencing was performed by next-generation sequencing for affected family members. Mutations were validated by Sanger sequencing. Functional experiments were performed to explore the deleterious effects of the identified mutation. DNA damage was induced by increasing mitomycin C (MMC) concentrations on cultured peripheral lymphocytes. Analysis of the next-generation sequencing data revealed a new homozygous missense mutation in the minichromosome maintenance 8 gene (MCM8).This homozygous mutation (c. 482A>C; p.His161Pro) was predicted to be deleterious and segregated with the disease in the family. MCM8 participates in homologous recombination during meiosis and DNA double-stranded break repair by dimerizing with MCM9. Mcm8 knock out results in an early block in follicle development and small gonads. Given this, we tested the chromosomal breakage repair capacity of homozygous and heterozygous MCM8 p.His161Pro mutation on cultured peripheral lymphocytes exposed to increasing MMC concentrations. We found that chromosomal breakage after MMC exposure was significantly higher in cells from homozygously affected individuals than in those from a healthy control. Our findings provide additional support to the view that MCM8 mutations are involved in the primary ovarian insufficiency phenotype. Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  8. Selective Preparation of trans-Carveol over Ceria Supported Mesoporous Materials MCM-41 and SBA-15

    Directory of Open Access Journals (Sweden)

    Nariman F. Salakhutdinov

    2013-05-01

    Full Text Available Ce-modified mesoporous silica materials MCM-41 and SBA-15, namely 32 wt % Ce–Si–MCM-41, 16 wt % Ce–H–MCM-41 and 20 wt % Ce–Si–SBA-15, were prepared, characterized and studied in the selective preparation of trans-carveol by α-pinene oxide isomerization. The characterizations of these catalysts were performed using scanning electron microscopy, X-ray photoelectron spectroscopy, nitrogen adsorption and FTIR pyridine adsorption. Selective preparation of trans-carveol was carried out in the liquid phase in a batch reactor. The activity and the selectivity of catalyst were observed to be influenced by their acidity, basicity and morphology of the mesoporous materials. The formation of trans-carveol is moreover strongly influenced by the basicity of the used solvent and in order to achieve high yields of this desired alcohol it is necessary to use polar basic solvent.

  9. KIF7 Controls the Proliferation of Cells of the Respiratory Airway through Distinct Microtubule Dependent Mechanisms.

    Directory of Open Access Journals (Sweden)

    Garry L Coles

    2015-10-01

    Full Text Available The cell cycle must be tightly coordinated for proper control of embryonic development and for the long-term maintenance of organs such as the lung. There is emerging evidence that Kinesin family member 7 (Kif7 promotes Hedgehog (Hh signaling during embryonic development, and its misregulation contributes to diseases such as ciliopathies and cancer. Kif7 encodes a microtubule interacting protein that controls Hh signaling through regulation of microtubule dynamics within the primary cilium. However, whether Kif7 has a function in nonciliated cells remains largely unknown. The role Kif7 plays in basic cell biological processes like cell proliferation or cell cycle progression also remains to be elucidated. Here, we show that Kif7 is required for coordination of the cell cycle, and inactivation of this gene leads to increased cell proliferation in vivo and in vitro. Immunostaining and transmission electron microscopy experiments show that Kif7dda/dda mutant lungs are hyperproliferative and exhibit reduced alveolar epithelial cell differentiation. KIF7 depleted C3H10T1/2 fibroblasts and Kif7dda/dda mutant mouse embryonic fibroblasts have increased growth rates at high cellular densities, suggesting that Kif7 may function as a general regulator of cellular proliferation. We ascertained that in G1, Kif7 and microtubule dynamics regulate the expression and activity of several components of the cell cycle machinery known to control entry into S phase. Our data suggest that Kif7 may function to regulate the maintenance of the respiratory airway architecture by controlling cellular density, cell proliferation, and cycle exit through its role as a microtubule associated protein.

  10. MCM-41 functionalized with YVO{sub 4}:Eu{sup 3+}: a novel drug delivery system

    Energy Technology Data Exchange (ETDEWEB)

    Yang Piaoping [Key Laboratory of Rare Earth Chemistry and Physics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Quan Zewei [Key Laboratory of Rare Earth Chemistry and Physics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Lu Lanlan [Key Laboratory of Rare Earth Chemistry and Physics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Huang Shanshan [Key Laboratory of Rare Earth Chemistry and Physics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Lin Jun [Key Laboratory of Rare Earth Chemistry and Physics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Fu Honggang [School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080 (China)

    2007-06-13

    Luminescence functionalization of ordered mesoporous MCM-41 silica was realized by depositing a YVO{sub 4}:Eu{sup 3+} phosphor layer on its surface via the Pechini sol-gel process. This material, which combines the mesoporous structure of MCM-41 and the strong red luminescence property of YVO{sub 4}:Eu{sup 3+}, has been studied as a host carrier for drug delivery/release systems. The structure, morphology, texture and optical properties of Materials were well characterized by x-ray diffraction (XRD), Fourier infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), N{sub 2} adsorption and photoluminescence (PL) spectra. The results indicated that the specific surface area and pore volume of MCM-41, which were directly correlated to the drug-loading amount and ibuprofen (IBU) release rate, decreased in sequence after deposition of YVO{sub 4}:Eu{sup 3+} and loading of IBU as expected. The IBU-loaded YVO{sub 4}:Eu{sup 3+}MCM-41 system still showed red luminescence under UV irradiation (365 nm) and a controlled release property for IBU. In addition, the emission intensity of Eu{sup 3+} increases with an increase in the cumulative released amount of IBU, making the extent of drug release easily identified, tracked and monitored by the change of luminescence, which demonstrates its potential application in drug delivery/release systems.

  11. Suppression of ERβ signaling via ERβ knockout or antagonist protects against bladder cancer development.

    Science.gov (United States)

    Hsu, Iawen; Chuang, Kun-Lung; Slavin, Spencer; Da, Jun; Lim, Wei-Xun; Pang, See-Tong; O'Brien, Jeanne H; Yeh, Shuyuan

    2014-03-01

    Epidemiological studies showed that women have a lower bladder cancer (BCa) incidence, yet higher muscle-invasive rates than men, suggesting that estrogen and the estrogen receptors, estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ), may play critical roles in BCa progression. Using in vitro cell lines and an in vivo carcinogen N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN)-induced mouse BCa model, we found that ERβ plays a positive role in promoting BCa progression. Knockdown of ERβ with ERβ-shRNA in ERβ-positive human BCa J82, 647v and T24 cell lines led to suppressed cell growth and invasion. Mice lacking ERβ have less cancer incidence with reduced expression of the proliferation marker Ki67 in BBN-induced BCa. Consistently, our results show that non-malignant urothelial cells with ERβ knockdown are more resistant to carcinogen-induced malignant transformation. Mechanism dissection found that targeting ERβ suppressed the expression of minichromosome maintenance complex component 5 (MCM5), a DNA replication licensing factor that is involved in tumor cell growth. Restoring MCM5 expression can partially reverse ERβ knockdown-mediated growth reduction. Supportively, treating cells with the ERβ-specific antagonist, 4-[2-Phenyl-5,7-bis(trifluoromethyl) pyrazolo[1,5-a]pyrimidin-3-yl]phenol (PHTPP), reduced BCa cell growth and invasion, as well as MCM5 expression. Furthermore, we provide the first evidence that BCa burden and mortality can be controlled by PHTPP treatment in the carcinogen-induced BCa model. Together, these results demonstrate that ERβ could play positive roles in promoting BCa progression via MCM5 regulation. Targeting ERβ through ERβ-shRNA, PHTPP or via downstream targets, such as MCM5, could serve as potential therapeutic approaches to battle BCa.

  12. A potential bioactive wound dressing based on carboxymethyl cellulose/ZnO impregnated MCM-41 nanocomposite hydrogel.

    Science.gov (United States)

    Rakhshaei, Rasul; Namazi, Hassan

    2017-04-01

    Lack of antibacterial activity, deficient water vapor and oxygen permeability, and insufficient mechanical properties are disadvantages of existing wound dressings. Hydrogels could absorb wound exudates due to their strong swelling ratio and give a cooling sensation and a wet environment. To overcome these shortcomings, flexible nanocomposite hydrogel films was prepared through combination of zinc oxide impregnated mesoporous silica (ZnO-MCM-41) as a nano drug carrier with carboxymethyl cellulose (CMC) hydrogel. Citric acid was used as cross linker to avoid the cytotoxicity of conventional cross linkers. The prepared nanocomposite hydrogel was characterized using X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Zeta potential and UV-vis spectroscopy. Results of swelling and erosion tests showed CMC/ZnO nanocomposite hydrogel disintegrated during the first hours of the test. Using MCM-41 as a substrate for ZnO nanoparticles solved this problem and the CMC/ZnO-MCM-41 showed a great improvement in tensile strength (12%), swelling (100%), erosion (53%) and gas permeability (500%) properties. Drug delivery and antibacterial properties of the nanocomposite hydrogel films studied using tetracycline (TC) as a broad spectrum antibiotic and showed a sustained TC release. This could efficiently decrease bandage exchange. Cytocompatibility of the nanocomposite hydrogel films has been analyzed in adipose tissue-derived stem cells (ADSCs) and results showed cytocompatibility of CMC/ZnO-MCM-41. Based on these results the prepared CMC nanocomposite hydrogel containing ZnO impregnated MCM-41, could serve as a kind of promising wound dressing with sustained drug delivery properties. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Pore radius fine tuning of a silica matrix (MCM-41) based on the synthesis of alumina nanolayers with different thicknesses by atomic layer deposition

    International Nuclear Information System (INIS)

    Zemtsova, Elena G.; Arbenin, Andrei Yu.; Plotnikov, Alexander F.; Smirnov, Vladimir M.

    2015-01-01

    The authors investigated a new approach to modify the surface of the mesoporous silica matrix MCM-41. This approach is based on manipulating the chemical composition of the porous surface layer and also on fine tuning the pore radius by applying the atomic layer deposition (ALD) technique. The synthesis of alumina nanolayers was performed on the planar and the porous matrix (MCM-41) by the ALD technique using aluminum tri-sec-butoxide and water as precursors. The authors show that one cycle on silicon, using aluminum tri-sec-butoxide and water as precursors, results in a 1–1.2 Å increase in alumina nanolayer thickness. This is comparable to the increase in thickness per cycle for other precursors such as trimethylaluminum and aluminum chloride. The authors show that the synthesis of an Al 2 O 3 nanolayer on the pore surface of the mesoporous silica matrix MCM-41 by the ALD technique results in a regular change in the porous structure of the samples. The specific porosity (ml/g) of the MCM-41 was 0.95 and that of MCM-41 after 5 ALD cycles was 0.39. The pore diameter (nm) of MCM-41 was 3.3 and that of MCM-41 after 5 ALD cycles was 2.3

  14. MicroRNA-613 represses prostate cancer cell proliferation and invasion through targeting Frizzled7

    International Nuclear Information System (INIS)

    Ren, Wei; Li, Chan; Duan, Wanli; Du, Shuangkuan; Yang, Fan; Zhou, Jiancheng; Xing, Junping

    2016-01-01

    A growing number of studies have indicated that microRNAs (miRNAs) are critical regulators of carcinogenesis and cancer progression and may serve as potential therapeutic tools for cancer therapy. Frizzled7 (Fzd7), the most important receptor of the Wnt signaling pathway, is extensively involved in cancer development and progression. However, the role of Fzd7 in prostate cancer remains unclear. In this study, we aimed to explore the expression of Fzd7 in prostate cancer and test whether modulating Fzd7 expression by miR-613 would have an impact on prostate cancer cell proliferation and invasion. We found that Fzd7 was highly expressed in prostate cancer cell lines. Through bioinformatics analysis, Fzd7 was predicted as a target gene of miR-613, which was validated by dual-luciferase reporter assays, real-time quantitative polymerase chain reaction and Western blot analysis. By gain of function experiments, we showed that overexpression of miR-613 significantly suppressed prostate cancer cell proliferation and invasion. Furthermore, miR-613 overexpression markedly downregulated the Wnt signaling pathway. Through a rescue experiment, we showed that overexpression of Fzd7 could abrogate the inhibitory effect of miR-613 on cell proliferation and invasion as well as Wnt signaling. Additionally, these results were further strengthened by data showing that miR-613 was significantly downregulated in prostate cancer tissues, exhibiting an inverse correlation with Fzd7 expression. In conclusion, our study suggests that miR-613 functions as a tumor suppressor, partially through targeting Fzd7, and is a potential therapeutic target for prostate cancer. - Highlights: • Fzd7 was highly expressed in prostate cancer. • Fzd7 was predicted as a target gene of miR-613. • MiR-613 negatively regulated prostate cancer by Fzd7. • MiR-613 inversely correlated with Fzd7 in prostate cancer.

  15. MicroRNA-613 represses prostate cancer cell proliferation and invasion through targeting Frizzled7

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Wei [Medical College of Xi' an Jiao Tong University, Xi' an 710061 (China); Department of Urology, Shaanxi Provincial People' s Hospital, The Third Affiliated Hospital of Xi' an Jiaotong University, Xi' an 710068 (China); Li, Chan [Department of Ophthalmology, Shaanxi Provincial People' s Hospital, The Third Affiliated Hospital of Xi' an Jiaotong University, Xi' an 710068 (China); Duan, Wanli; Du, Shuangkuan; Yang, Fan; Zhou, Jiancheng [Department of Urology, Shaanxi Provincial People' s Hospital, The Third Affiliated Hospital of Xi' an Jiaotong University, Xi' an 710068 (China); Xing, Junping, E-mail: junpingxing@163.com [Department of Urology, The First Affiliated Hospital of Xi' an Jiaotong University, Xi' an 710061 (China)

    2016-01-15

    A growing number of studies have indicated that microRNAs (miRNAs) are critical regulators of carcinogenesis and cancer progression and may serve as potential therapeutic tools for cancer therapy. Frizzled7 (Fzd7), the most important receptor of the Wnt signaling pathway, is extensively involved in cancer development and progression. However, the role of Fzd7 in prostate cancer remains unclear. In this study, we aimed to explore the expression of Fzd7 in prostate cancer and test whether modulating Fzd7 expression by miR-613 would have an impact on prostate cancer cell proliferation and invasion. We found that Fzd7 was highly expressed in prostate cancer cell lines. Through bioinformatics analysis, Fzd7 was predicted as a target gene of miR-613, which was validated by dual-luciferase reporter assays, real-time quantitative polymerase chain reaction and Western blot analysis. By gain of function experiments, we showed that overexpression of miR-613 significantly suppressed prostate cancer cell proliferation and invasion. Furthermore, miR-613 overexpression markedly downregulated the Wnt signaling pathway. Through a rescue experiment, we showed that overexpression of Fzd7 could abrogate the inhibitory effect of miR-613 on cell proliferation and invasion as well as Wnt signaling. Additionally, these results were further strengthened by data showing that miR-613 was significantly downregulated in prostate cancer tissues, exhibiting an inverse correlation with Fzd7 expression. In conclusion, our study suggests that miR-613 functions as a tumor suppressor, partially through targeting Fzd7, and is a potential therapeutic target for prostate cancer. - Highlights: • Fzd7 was highly expressed in prostate cancer. • Fzd7 was predicted as a target gene of miR-613. • MiR-613 negatively regulated prostate cancer by Fzd7. • MiR-613 inversely correlated with Fzd7 in prostate cancer.

  16. Sulphonated cobalt phthalocyanine-MCM-41: An active photocatalyst for degradation of 2,4-dichlorophenol

    Energy Technology Data Exchange (ETDEWEB)

    Zanjanchi, M.A., E-mail: zanjanchi@guilan.ac.ir [Department of Chemistry, Faculty of Science, University of Guilan, P.O. Box 1914, Namjoo St., Rasht 41335 (Iran, Islamic Republic of); Ebrahimian, A.; Arvand, M. [Department of Chemistry, Faculty of Science, University of Guilan, P.O. Box 1914, Namjoo St., Rasht 41335 (Iran, Islamic Republic of)

    2010-03-15

    The photocatalytic activity of sulphonated cobalt phthalocyanine immobilized onto MCM-41 was investigated for decomposition of 2,4-dichlorophenol (2,4-DCP) in aqueous solutions. Immobilization of anion sulpho-cobalt phthalocyanine to the walls of MCM-41 was performed by pre-anchorage of 3-(aminopropyl)-triethoxysilane (APTES) onto MCM-41 via post-synthesis method. X-ray diffraction, nitrogen physisorption, diffuse reflectance spectroscopy, energy-dispersive X-ray and FT-IR methods were used to characterize the product. Photocatalytic efficiency of the prepared catalyst for degradation of 2,4-DCP was tested under illumination of UV-A and visible light. The results obtained reveal that the photocatalyst is very active in degradation of 2,4-DCP. The photodegradation process is completed within 3 h using a dose of 0.6 g/L of the catalyst under UV irradiation. The reactions follow a pseudo-first-order kinetics and the observed rate constant values change with 2,4-DCP concentrations. The reproducibility of the catalyst was tested. The reaction intermediates were identified by gas chromatoghraphy-mass spectrometery (GC-MS) technique.

  17. Multifunctional materials such as MCM-41÷Fe3O4÷folic acid as drug delivery system.

    Science.gov (United States)

    Popescu, Simona; Ardelean, Ioana Lavinia; Gudovan, Dragoş; Rădulescu, Marius; Ficai, Denisa; Ficai, Anton; Vasile, Bogdan Ştefan; Andronescu, Ecaterina

    2016-01-01

    In this study, MCM-41 mesoporous silica nanoparticles (NPs) and MCM-41÷Fe3O4 mesoporous silica NPs were prepared by sol-gel method using CTAB (cetyltrimethylammonium bromide) as template and TEOS (tetraethyl orthosilicate) as silica precursor in order to use these materials as drug delivery system (DDS) for different biologically active agents. The MCM-41 and MCM-41÷Fe3O4 mesoporous silica NPs were characterized using specific physico-chemical methods [transmission electron microscopy (TEM), scanning electron microscopy (SEM), nitrogen adsorption and desorption studies - BET (Brunauer-Emmett-Teller) method, X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy], while the release studies were done by a high-performance liquid chromatography (HPLC)-modified method. The pH dependence of the delivery of folic acid from the mesoporous structures was analyzed and found that the release is pH sensitive. The lower delivery at strongly acid pH comparing with neutral/slightly alkaline pH could be beneficial because in stomach the folic acid can be destroyed.

  18. Amino-functionalized mesoporous MCM-41 silica as an efficient adsorbent for water treatment: batch and fixed-bed column adsorption of the nitrate anion

    Science.gov (United States)

    Ebrahimi-Gatkash, Mehdi; Younesi, Habibollah; Shahbazi, Afsaneh; Heidari, Ava

    2017-07-01

    In the present study, amino-functionalized Mobil Composite Material No. 41 (MCM-41) was used as an adsorbent to remove nitrate anions from aqueous solutions. Mono-, di- and tri-amino functioned silicas (N-MCM-41, NN-MCM-41 and NNN-MCM-41) were prepared by post-synthesis grafting method. The samples were characterized by means of X-ray powder diffraction, FTIR spectroscopy, thermogravimetric analysis, scanning electron microscopy and nitrogen adsorption-desorption. The effects of pH, initial concentration of anions, and adsorbent loading were examined in batch adsorption system. Results of adsorption experiments showed that the adsorption capacity increased with increasing adsorbent loading and initial anion concentration. It was found that the Langmuir mathematical model indicated better fit to the experimental data than the Freundlich. According to the constants of the Langmuir equation, the maximum adsorption capacity for nitrate anion by N-MCM-41, NN-MCM-41 and NNN-MCM-41 was found to be 31.68, 38.58 and 36.81 mg/g, respectively. The adsorption kinetics were investigated with pseudo-first-order and pseudo-second-order model. Adsorption followed the pseudo-second-order rate kinetics. The coefficients of determination for pseudo-second-order kinetic model are >0.99. For continuous adsorption experiments, NNN-MCM-41 adsorbent was used for the removal of nitrate anion from solutions. Breakthrough curves were investigated at different bed heights, flow rates and initial nitrate anion concentrations. The Thomas and Yan models were utilized to calculate the kinetic parameters and to predict the breakthrough curves of different bed height. Results from this study illustrated the potential utility of these adsorbents for nitrate removal from water solution.

  19. Mcm2 deficiency results in short deletions allowing high resolution identification of genes contributing to lymphoblastic lymphoma

    Science.gov (United States)

    Rusiniak, Michael E.; Kunnev, Dimiter; Freeland, Amy; Cady, Gillian K.; Pruitt, Steven C.

    2011-01-01

    Mini-chromosome maintenance (Mcm) proteins are part of the replication licensing complex that is loaded onto chromatin during the G1-phase of the cell cycle and required for initiation of DNA replication in the subsequent S-phase. Mcm proteins are typically loaded in excess of the number of locations that are utilized during S-phase. Nonetheless, partial depletion of Mcm proteins leads to cancers and stem cell deficiencies. Mcm2 deficient mice, on a 129Sv genetic background, display a high rate of thymic lymphoblastic lymphoma. Here array comparative genomic hybridization (aCGH) is utilized to characterize the genetic damage accruing in these tumors. The predominant events are deletions averaging less than 0.5 Mb, considerably shorter than observed in prior studies using alternative mouse lymphoma models or human tumors. Such deletions facilitate identification of specific genes and pathways responsible for the tumors. Mutations in many genes that have been implicated in human lymphomas are recapitulated in this mouse model. These features, and the fact that the mutation underlying the accelerated genetic damage does not target a specific gene or pathway a priori, are valuable features of this mouse model for identification of tumor suppressor genes. Genes affected in all tumors include Pten, Tcfe2a, Mbd3 and Setd1b. Notch1 and additional genes are affected in subsets of tumors. The high frequency of relatively short deletions is consistent with elevated recombination between nearby stalled replication forks in Mcm2 deficient mice. PMID:22158038

  20. The 11C-radioisotopic study of methanol conversion on V-MCM-41; the influence of methyl iodide on the transformation

    International Nuclear Information System (INIS)

    Sarkadi-Priboczki, E.; Szelecsenyi, F.; Kovacs, Z.; Solmaz, A.; Balci, S.; Dogu, T.

    2007-01-01

    Complete text of publication follows. The MCM-41 mesoporous material has Lewis and even Bronsted acid sites to produce dimethyl ether with some hydrocarbons, while over metal modified MCM-41 mostly formaldehyde and dimethoxy methane (i.e. methylal) or methyl formate are produced. In present experiments V incorporated basically mild acid sites of MCM-41 was prepared by low temperature direct synthesis. The V-MCM-41 has enough main active Lewis sites (by V-) to form formaldehyde and also light Bronsted acid sites to let the adsorbed formaldehyde eliminate and afterwards, with methanol, to form dimethoxy methane in nonoxidative environment. This V-MCM-41 has been tested by ethanol conversion in non-oxidative environments too and diethoxy methane as main product was detected. In present work the methanol conversion, as well as the methanol co-reaction with methyl iodide are studied from the same V-MCM-41 sample using 11 C-technique. The 11 C-labelled radioactive methanol has been already applied for determination of methanol conversion rates on Cu-modified MCM-41. The V-MCM-41 was prepared by direct hydrothermal synthesis method. The adsorption rate of 11 C-methanol and, after the reaction, the desorption rate of the remaining 11 C-derivatives on catalyst were continuously detected by gamma detectors. The derivatives were analyzed by radio-gas chromatography (gas chromatograph with FID coupled on-line with a radioactivity detector). Both dimethyl ether and hydrocarbon formation are also in slight degrees according to weak Lewis and Bronsted acidities. Since the conversion was carried out without added oxygen gas, only the frame oxygen can take part into catalysis. In presence of non-radioactive methyl iodide, the radioactive methanol is converted to radioactive methyl iodide on V-MCM-41. The radio-GC analysis confirmed that the iodide induced change of the reaction performance was reversible i.e. the radioactive methyl iodide was regenerated to non-radioactive methyl

  1. Development of the MCM-D technique for pixel detector modules

    CERN Document Server

    Grah, Christian

    2005-01-01

    This thesis treats a copper--polymer based thin film technology, the MCM-D technique and its application when building hybrid pixel detector modules. The ATLAS experiment at the LHC will be equipped with a pixel detector system. The basic mechanical units of the pixel detector are multi chip modules. The main components of these modules are: 16 electronic chips, a controller chip and a large sensor tile, featuring more than 46000 sensor cells. MCM-D is a superior technique to build the necessary signal bus system and the power distribution system directly on the active sensor tile. In collaboration with the Fraunhofer Institute for Reliability and Microintegration, IZM, the thin film process is reviewed and enhanced. The multi layer system was designed and optimized for the interconnection system as well as for the 46000 pixel contacts. Laboratory measurements on prototypes prove that complex routing schemes for geometrically optimized single chips are suitable and have negligible influence on the front--end ...

  2. Prospects of Fe/MCM-41 as a Catalyst for Hydrocarbon Synthesis

    International Nuclear Information System (INIS)

    Cagnoli, Maria V.; Gallegos, Norma G.; Bengoa, Jose F.; Alvarez, Ana M.; Marchetti, Sergio G.; Moreno, Sergio M. J.; Roig, Anna; Mercader, Roberto C.

    2005-01-01

    We report the synthesis of cylindrical nanoparticles of metallic Fe entirely included in MCM-41 pores. Their dimensions are approx.3 nm diameter and approx. 3.8 nm length. We show that a coherent analysis of the results yielded by the various techniques is essential to obtain a catalyst supported on an MCM-41 matrix of ≅ 3 nm average pore diameter, which is active and selective toward olefins. The solids were characterized by low-angle x-ray diffraction, high-resolution transmission electron microscopy, high-resolution scanning transmission electron microscopy equipped with a high-angle annular dark-field, CO chemisorption, volumetric oxidation, and Moessbauer spectroscopy (in controlled atmosphere for the reduced catalysts). Catalytic results in the Fischer-Tropsch synthesis, as well as some unexpected results --like the inhomogeneous pore filling and discontinuous Fe particles-- are also discussed

  3. Regulation of proliferation and differentiation of adipocyte precursor cells in rainbow trout (Oncorhynchus mykiss).

    Science.gov (United States)

    Bouraoui, L; Gutiérrez, J; Navarro, I

    2008-09-01

    Here, we describe optimal conditions for the culture of rainbow trout (Oncorhynchus mykiss) pre-adipocytes obtained from adipose tissue and their differentiation into mature adipocytes, in order to study the endocrine control of adipogenesis. Pre-adipocytes were isolated by collagenase digestion and cultured on laminin or 1% gelatin substrate. The expression of proliferating cell nuclear antigen was used as a marker of cell proliferation on various days of culture. Insulin growth factor-I stimulated cell proliferation especially on days 5 and 7 of culture. Tumor necrosis factor alpha (TNFalpha) slightly enhanced cell proliferation only at a low dose. We verified the differentiation of cells grown in specific medium into mature adipocytes by oil red O (ORO) staining. Quantification of ORO showed an increase in triglycerides throughout culture. Immunofluorescence staining of cells at day 11 revealed the expression of CCAAT/enhancer-binding protein and peroxisome proliferator-activator receptor gamma, suggesting that these transcriptional factors are involved in adipocyte differentiation in trout. We also examined the effect of TNFalpha on the differentiation of these adipocytes in primary culture. TNFalpha inhibited the differentiation of these cells, as indicated by a decrease in glycerol-3-phosphate dehydrogenase activity, an established marker of adipocyte differentiation. In conclusion, the culture system described here for trout pre-adipocytes is a powerful tool to study the endocrine regulation of adipogenesis in this species.

  4. Synthesis and characterization of mesoporous Si–MCM-41 ...

    Indian Academy of Sciences (India)

    Administrator

    Table S1. MCM-41 synthesis strategies—parameters optimized. BET surface area at different temperature (m2/g). SiO2. Template Template H2O Temp. Aging. Parameters. No. source source mole mole. (°C) time (h) pH. 550 °C. 700 °C. 900 °C. Aging time. 1. Na2SiO3. CTABr. 0⋅25. 80. RT. 1. 10⋅5. 640. 490. 370. 2.

  5. Zinc(II) phthalocyanines immobilized in mesoporous silica Al-MCM-41 and their applications in photocatalytic degradation of pesticides

    Energy Technology Data Exchange (ETDEWEB)

    Silva, M. [Departamento de Quimica, Universidade de Coimbra, Rua Larga, 3004-535 Coimbra (Portugal); Laboratoire de Photochimie Moleculaire et Macromoleculaire, UMR CNRS 6505, Universite Blaise Pascal, F-63177 Aubiere cedex (France); Calvete, M.J.F.; Goncalves, N.P.F.; Burrows, H.D. [Departamento de Quimica, Universidade de Coimbra, Rua Larga, 3004-535 Coimbra (Portugal); Sarakha, M. [Laboratoire de Photochimie Moleculaire et Macromoleculaire, UMR CNRS 6505, Universite Blaise Pascal, F-63177 Aubiere cedex (France); Fernandes, A.; Ribeiro, M.F. [Instituto para a Biotecnologia e Bioengenharia, Centro para a Engenharia Biologica e Quimica, Instituto Superior Tecnico - Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Azenha, M.E., E-mail: meazenha@ci.uc.pt [Departamento de Quimica, Universidade de Coimbra, Rua Larga, 3004-535 Coimbra (Portugal); Pereira, M.M., E-mail: mmpereira@qui.uc.pt [Departamento de Quimica, Universidade de Coimbra, Rua Larga, 3004-535 Coimbra (Portugal)

    2012-09-30

    Highlights: Black-Right-Pointing-Pointer Complete immobilization of zinc(II) phthalocyanines accomplished in Al-MCM-41. Black-Right-Pointing-Pointer Efficient photodegradation of model pesticides achieved using 365 nm irradiation. Black-Right-Pointing-Pointer Sodium azide experiments showed the involvement of singlet oxygen ({sup 1}O{sub 2}). - Abstract: In the present study the authors investigated a set of three new zinc(II) phthalocyanines (zinc(II) tetranitrophthalocyanine (ZnTNPc), zinc(II) tetra(phenyloxy)phthalocyanine (ZnTPhOPc) and the tetraiodide salt of zinc(II)tetra(N,N,N-trimethylaminoethyloxy) phthalocyaninate (ZnTTMAEOPcI)) immobilized into Al-MCM-41 prepared via ship-in-a-bottle methodology. The samples were fully characterized by diffuse reflectance-UV-vis spectroscopy (DRS-UV-vis), luminescence, thermogravimetric analysis (TG/DSC), N{sub 2} adsorption techniques and elemental analysis. A comparative study was made on the photocatalytic performance upon irradiation within the wavelength range 320-460 nm of these three systems in the degradation of pesticides fenamiphos and pentachlorophenol. ZnTNPc-Al-MCM-41 and ZnTTMAEOPcI-Al-MCM-41 were found to be the most active systems, with the best performance observed with the immobilized cationic phthalocyanine, ZnTTMAEOPcI-Al-MCM-41. This system showed high activity even after three photocatalytic cycles. LC-MS product characterization and mechanistic studies indicate that singlet oxygen ({sup 1}O{sub 2}), produced by excitation of these immobilized photosensitizers, is a key intermediate in the photocatalytic degradation of both pesticides.

  6. Zinc(II) phthalocyanines immobilized in mesoporous silica Al-MCM-41 and their applications in photocatalytic degradation of pesticides

    International Nuclear Information System (INIS)

    Silva, M.; Calvete, M.J.F.; Gonçalves, N.P.F.; Burrows, H.D.; Sarakha, M.; Fernandes, A.; Ribeiro, M.F.; Azenha, M.E.; Pereira, M.M.

    2012-01-01

    Highlights: ► Complete immobilization of zinc(II) phthalocyanines accomplished in Al-MCM-41. ► Efficient photodegradation of model pesticides achieved using 365 nm irradiation. ► Sodium azide experiments showed the involvement of singlet oxygen ( 1 O 2 ). - Abstract: In the present study the authors investigated a set of three new zinc(II) phthalocyanines (zinc(II) tetranitrophthalocyanine (ZnTNPc), zinc(II) tetra(phenyloxy)phthalocyanine (ZnTPhOPc) and the tetraiodide salt of zinc(II)tetra(N,N,N-trimethylaminoethyloxy) phthalocyaninate (ZnTTMAEOPcI)) immobilized into Al-MCM-41 prepared via ship-in-a-bottle methodology. The samples were fully characterized by diffuse reflectance-UV–vis spectroscopy (DRS-UV–vis), luminescence, thermogravimetric analysis (TG/DSC), N 2 adsorption techniques and elemental analysis. A comparative study was made on the photocatalytic performance upon irradiation within the wavelength range 320–460 nm of these three systems in the degradation of pesticides fenamiphos and pentachlorophenol. ZnTNPc-Al-MCM-41 and ZnTTMAEOPcI-Al-MCM-41 were found to be the most active systems, with the best performance observed with the immobilized cationic phthalocyanine, ZnTTMAEOPcI-Al-MCM-41. This system showed high activity even after three photocatalytic cycles. LC–MS product characterization and mechanistic studies indicate that singlet oxygen ( 1 O 2 ), produced by excitation of these immobilized photosensitizers, is a key intermediate in the photocatalytic degradation of both pesticides.

  7. Investigation of Room Temperature Synthesis of Titanium Dioxide Nanoclusters Dispersed on Cubic MCM-48 Mesoporous Materials

    OpenAIRE

    Sridhar Budhi; Chia-Ming Wu; Dan Zhao; Ranjit T. Koodali

    2015-01-01

    Titania containing cubic MCM-48 mesoporous materials were synthesized successfully at room temperature by a modified Stöber method. The integrity of the cubic mesoporous phase was retained even at relatively high loadings of titania. The TiO2-MCM-48 materials were extensively characterized by a variety of physico-chemical techniques. The physico-chemical characterization indicate that Ti4+ ions can be substituted in framework tetrahedral positions. The relative amount of Ti4+ ions in tetrahe...

  8. Platelet-rich plasma stimulated by pulse electric fields: Platelet activation, procoagulant markers, growth factor release and cell proliferation.

    Science.gov (United States)

    Frelinger, A L; Torres, A S; Caiafa, A; Morton, C A; Berny-Lang, M A; Gerrits, A J; Carmichael, S L; Neculaes, V B; Michelson, A D

    2016-01-01

    Therapeutic use of activated platelet-rich plasma (PRP) has been explored for wound healing, hemostasis and antimicrobial wound applications. Pulse electric field (PEF) stimulation may provide more consistent platelet activation and avoid complications associated with the addition of bovine thrombin, the current state of the art ex vivo activator of therapeutic PRP. The aim of this study was to compare the ability of PEF, bovine thrombin and thrombin receptor activating peptide (TRAP) to activate human PRP, release growth factors and induce cell proliferation in vitro. Human PRP was prepared in the Harvest SmartPreP2 System and treated with vehicle, PEF, bovine thrombin, TRAP or Triton X-100. Platelet activation and procoagulant markers and microparticle generation were measured by flow cytometry. Released growth factors were measured by ELISA. The releasates were tested for their ability to stimulate proliferation of human epithelial cells in culture. PEF produced more platelet-derived microparticles, P-selectin-positive particles and procoagulant annexin V-positive particles than bovine thrombin or TRAP. These differences were associated with higher levels of released epidermal growth factor after PEF than after bovine thrombin or TRAP but similar levels of platelet-derived, vascular-endothelial, and basic fibroblast growth factors, and platelet factor 4. Supernatant from PEF-treated platelets significantly increased cell proliferation compared to plasma. In conclusion, PEF treatment of fresh PRP results in generation of microparticles, exposure of prothrombotic platelet surfaces, differential release of growth factors compared to bovine thrombin and TRAP and significant cell proliferation. These results, together with PEF's inherent advantages, suggest that PEF may be a superior alternative to bovine thrombin activation of PRP for therapeutic applications.

  9. The Fbw7 tumor suppressor targets KLF5 for ubiquitin-mediated degradation and suppresses breast cell proliferation.

    Science.gov (United States)

    Zhao, Dong; Zheng, Han-Qiu; Zhou, Zhongmei; Chen, Ceshi

    2010-06-01

    Fbw7 is a tumor suppressor frequently inactivated in cancers. The KLF5 transcription factor promotes breast cell proliferation and tumorigenesis through upregulating FGF-BP. The KLF5 protein degrades rapidly through the ubiquitin proteasome pathway. Here, we show that the Skp1-CUL1-Fbw7 E3 ubiquitin ligase complex (SCF(Fbw7)) targets KLF5 for ubiquitin-mediated degradation in a GSK3beta-mediated KLF5 phosphorylation-dependent manner. Mutation of the critical S303 residue in the KLF5 Cdc4 phospho-degrons motif ((303)SPPSS) abolishes the protein interaction, ubiquitination, and degradation by Fbw7. Inactivation of endogenous Fbw7 remarkably increases the endogenous KLF5 protein abundances. Endogenous Fbw7 suppresses the FGF-BP gene expression and breast cell proliferation through targeting KLF5 for degradation. These findings suggest that Fbw7 inhibits breast cell proliferation at least partially through targeting KLF5 for proteolysis. This new regulatory mechanism of KLF5 degradation may result in useful diagnostic and therapeutic targets for breast cancer and other cancers. Copyright 2010 AACR.

  10. CO2 capture on micro/meso-porous composites of (zeolite A)/(MCM-41) with Ca2+ located: Computer simulation and experimental studies

    International Nuclear Information System (INIS)

    Jianhai Zhou; Huiling Zhao; Jinxia Li; Yujun Zhu; Jun Hu; Honglai Liu; Ying Hu

    2013-01-01

    Composing of both zeolite and meso-porous structures, micro/meso-porous composites exhibit promising CO 2 capture capabilities. In this work, a full-atomic mimetic 5A-MCM-41 structure with bimodal pores has been constructed, in which the microporous structure of 5A zeolite is constructed and optimized based on zeolite A with Ca and Na cations introduced; whereas the meso-porous MCM-41 structure is produced by caving the cylindrical pores in the obtained 5A zeolite matrix. CO 2 adsorption on 5A-MCM- 41 has been simulated by the grand canonical Monte Carlo (GCMC). The simulation results demonstrated that CO 2 is preferentially adsorbed in micropores, and the CO 2 adsorption capacity and its isosteric heat on 5A-MCM-41 are much larger than those of N 2 . The CO 2 selectivity of 5A-MCM-41 results from the electrostatic interaction of the quadrupole CO 2 molecule with Ca 2+ cations of the zeolite. Furthermore, the hierarchical micro/meso-porous composites are synthesized to verify the simulated predictions. By the hydrothermal reaction using 5A zeolite 'seeds' as the silicon source and hexadecyl trimethylammonium bromide (CTAB) as the meso-porous template, 5A-MCM-41 composites are obtained, the characteristic results show that typical 5A microporous structure is remained and disordered meso-porous networks are produced in the composites.Moreover, the CO 2 adsorption capacity of the 5A-MCM- 41 composites can reach as high as 4.08 mmol/g at 100 kPa and 298 K. These observations have been strongly supported that micro/meso-porous composites with metal ions located would be promising adsorbents for CO 2 separation. (authors)

  11. The correlation of adsorption behavior between ciprofloxacin hydrochloride and the active sites of Fe-doped MCM-41

    Science.gov (United States)

    Wu, Ying; Tang, Yiming; Li, Laisheng; Liu, Peihong; Li, Xukai; Chen, Weirui; Xue, Ying

    2018-02-01

    Fe-MCM-41s with various molar ratios of silicon to iron (20, 40, 80 and 160) were prepared to investigate adsorption properties of ciprofloxacin hydrochloride (CPX) in aqueous solutions. Fe-MCM-41s were characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption/desorption isotherms and infrared spectroscopy (FT-IR). Effects of silicon–iron ratio, adsorbent dosage, pH and temperature were conducted to explore the adsorption mechanism of CPX on Fe-MCM-41. The results showed that the introduction of iron facilitated the absorption quantity for CPX from 20.04 to 83.33 mg g-1 at 120 min of reaction time, which was mainly attributed to surface complexation. The promotion of hydrophobic effect, electrostatic interactions and π-π electron donor–acceptor interaction also played coordinate roles in the adsorption process. The experimental kinetic data followed both the pseudo-second-order and intra-particle diffusion models, while the adsorption isotherm data fit well to Freundlich model at high temperature. Thermodynamic study showed that the adsorption was spontaneous. Under the effect of electrostatic interaction, pH of the solution strongly affected CPX adsorption. Five representative metal cations (Ca, Cu, Ni, Pb and Cd) were chosen to study the effects on CPX adsorption and their complexation. The inhibiting effect of metal cations on CPX adsorption was sequenced in the order of Cu > Ni > Pb > Cd > Ca, which followed the same order as the complexation stability constants between CPX and cations. The Fe-MCM-41 adsorbent possessed excellent reusability for 4 cycles use, suggesting a potential applicability of Fe-MCM-41 to remove CPX in water.

  12. Expression of WNT genes in cervical cancer-derived cells: Implication of WNT7A in cell proliferation and migration

    International Nuclear Information System (INIS)

    Ramos-Solano, Moisés; Meza-Canales, Ivan D.; Torres-Reyes, Luis A.; Alvarez-Zavala, Monserrat

    2015-01-01

    According to the multifactorial model of cervical cancer (CC) causation, it is now recognized that other modifications, in addition to Human papillomavirus (HPV) infection, are necessary for the development of this neoplasia. Among these, it has been proposed that a dysregulation of the WNT pathway might favor malignant progression of HPV-immortalized keratinocytes. The aim of this study was to identify components of the WNT pathway differentially expressed in CC vs. non-tumorigenic, but immortalized human keratinocytes. Interestingly, WNT7A expression was found strongly downregulated in cell lines and biopsies derived from CC. Restoration of WNT7A in CC-derived cell lines using a lentiviral gene delivery system or after adding a recombinant human protein decreases cell proliferation. Likewise, WNT7A silencing in non-tumorigenic cells markedly accelerates proliferation. Decreased WNT7A expression was due to hypermethylation at particular CpG sites. To our knowledge, this is the first study reporting reduced WNT7A levels in CC-derived cells and that ectopic WNT7A restoration negatively affects cell proliferation and migration. - Highlights: • WNT7A is expressed in normal keratinocytes or cervical cells without lesion. • WNT7A is significantly reduced in cervical cancer-derived cells. • Restoration of WNT7A expression in HeLa decreases proliferation and cell migration. • Silencing of WNT7A in HaCaT induces an increased proliferation and migration rate. • Decreased WNT7A expression in this model is due to hypermethylation

  13. Expression of WNT genes in cervical cancer-derived cells: Implication of WNT7A in cell proliferation and migration

    Energy Technology Data Exchange (ETDEWEB)

    Ramos-Solano, Moisés, E-mail: mrsolano84@gmail.com [División de Inmunología, Centro de Investigación Biomédica de Occidente (CIBO)-Instituto Mexicano del Seguro Social (IMSS), Guadalajara, Jalisco (Mexico); Programa de Doctorado en Ciencias Biomédica, Centro Universitario de Ciencias de la Salud (CUCS), Universidad de Guadalajara, Guadalajara, Jalisco (Mexico); Meza-Canales, Ivan D., E-mail: imezacanales@ice.mpg.de [Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, 07745 Jena (Germany); Torres-Reyes, Luis A., E-mail: torres_reyes_88@hotmail.com [División de Inmunología, Centro de Investigación Biomédica de Occidente (CIBO)-Instituto Mexicano del Seguro Social (IMSS), Guadalajara, Jalisco (Mexico); Programa de Doctorado en Ciencias Biomédica, Centro Universitario de Ciencias de la Salud (CUCS), Universidad de Guadalajara, Guadalajara, Jalisco (Mexico); Alvarez-Zavala, Monserrat, E-mail: monse_belan@hotmail.com [División de Inmunología, Centro de Investigación Biomédica de Occidente (CIBO)-Instituto Mexicano del Seguro Social (IMSS), Guadalajara, Jalisco (Mexico); Programa de Doctorado en Ciencias Biomédica, Centro Universitario de Ciencias de la Salud (CUCS), Universidad de Guadalajara, Guadalajara, Jalisco (Mexico); and others

    2015-07-01

    According to the multifactorial model of cervical cancer (CC) causation, it is now recognized that other modifications, in addition to Human papillomavirus (HPV) infection, are necessary for the development of this neoplasia. Among these, it has been proposed that a dysregulation of the WNT pathway might favor malignant progression of HPV-immortalized keratinocytes. The aim of this study was to identify components of the WNT pathway differentially expressed in CC vs. non-tumorigenic, but immortalized human keratinocytes. Interestingly, WNT7A expression was found strongly downregulated in cell lines and biopsies derived from CC. Restoration of WNT7A in CC-derived cell lines using a lentiviral gene delivery system or after adding a recombinant human protein decreases cell proliferation. Likewise, WNT7A silencing in non-tumorigenic cells markedly accelerates proliferation. Decreased WNT7A expression was due to hypermethylation at particular CpG sites. To our knowledge, this is the first study reporting reduced WNT7A levels in CC-derived cells and that ectopic WNT7A restoration negatively affects cell proliferation and migration. - Highlights: • WNT7A is expressed in normal keratinocytes or cervical cells without lesion. • WNT7A is significantly reduced in cervical cancer-derived cells. • Restoration of WNT7A expression in HeLa decreases proliferation and cell migration. • Silencing of WNT7A in HaCaT induces an increased proliferation and migration rate. • Decreased WNT7A expression in this model is due to hypermethylation.

  14. Relationship of preoperative gastric cancer CT enhancement ratio and perfusion parameters with serum tumor marker levels and proliferation molecule expression in tumor lesions

    Directory of Open Access Journals (Sweden)

    Yong-Hong Wang

    2017-06-01

    Full Text Available Objective: To study the relationship of preoperative gastric cancer CT enhancement ratio and perfusion parameters with serum tumor marker levels and proliferation molecule expression in tumor lesions. Methods: A total of 68 patients with gastric cancer treated in the Second Hospital of Yulin City between May 2012 and May 2016 were chosen as observation group and sub-divided into early and middle gastric cancer group (n=41 and advanced gastric cancer group (n=27 according to the tumor stage; 50 patients diagnosed with benign gastric diseases in our hospital during the same period were selected as benign gastric lesion group. CT enhancement rate and perfusion parameters of three groups of patients were detected by CT scan, serum tumor marker levels were evacuated by enzyme-linked immunosorbent assay (ELISA, and the proliferation gene mRNA expression levels were detected by RTPCR method. Results: CER, AF, BV and CL levels of advanced gastric cancer group were higher than those of early and middle gastric cancer group and benign gastric lesion group; serum CA72-4, CA19-9, CA125 and CEA contents of advanced gastric cancer group were higher than those of early and middle gastric cancer group and benign gastric lesion group; CADM1, miRNA-34a and Cystatin M mRNA expression in tissue of advanced gastric cancer group were lower than those of early and middle gastric cancer group and benign gastric lesion group while Survivin and I2PP2A mRNA expression were higher than those of early and middle gastric cancer group and benign gastric lesion group. The Pearson test showed that the CT enhancement rate and perfusion parameters in patients with gastric cancer are directly correlated with the serum tumor marker levels and the proliferation gene expression in tumor lesions. Conclusion: Preoperative gastric cancer CT enhancement rate and perfusion parameters are directly related to the tumor malignancy, and can be used as a reliable method for the long-term tumor

  15. Hydrothermal synthesis of meso porous silica MCM-41 using commercial sodium silicate

    International Nuclear Information System (INIS)

    Melendez O, H. I.; Mercado S, A.; Garcia C, L. A.; Castruita, G.; Perera M, Y A.

    2013-01-01

    In this work, ordered meso porous silica MCM-41 was prepared by hydrothermal synthesis using industrial-grade sodium silicate (Na 2 SiO 3 ) as silica source, hexadecyltrimethyl-ammonium bromide (CTAB) as template agent and ethyl acetate as ph regulator. The influence of CTAB/SiO 2 molar ratio, reaction time, aging temperature, and co-surfactant type on the structural and morphological properties of the obtained silica was studied. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption isotherms. Ordered meso porous MCM-41 silica was obtained at 80 C by using a range of CTAB/SiO 2 molar ratio from 0.35 to 0.71 and reaction times up to 72 h and isopropanol (i-Pr OH) as co-surfactant. (Author)

  16. Synthesis and characterization of V, Mo and Nb incorporated micro-mesoporous MCM-41 materials

    Energy Technology Data Exchange (ETDEWEB)

    Solmaz, Arzu, E-mail: arzu.solmaz@rshm.gov.tr [Gazi University, Faculty of Engineering, Chemical Engineering Department, 06570 Ankara (Turkey); Balci, Suna, E-mail: sunabalci@gazi.edu.tr [Gazi University, Faculty of Engineering, Chemical Engineering Department, 06570 Ankara (Turkey); Dogu, Timur, E-mail: tdogu@metu.edu.tr [Middle East Technical University, Faculty of Engineering, Chemical Engineering Department, 06531 Ankara (Turkey)

    2011-01-01

    Highly microporous metal-MCM-41 ordered mesoporous structure catalysts having different metal/Si (V, Mo, Nb) atomic ratios and combinations of metal sources were hydrothermally synthesized. The structural properties estimated using different techniques were found to be in agreement with each other. Metals were successfully incorporated into MCM-41 without deteriorating the ordered hexagonal structure. The metal ions in the synthesis solutions probably settled on the hydrophilic end of the template hence the metal incorporation resulted improvements in the micropore structure. Low loading of metals caused an increase in the surface area and pore volume values of the catalysts. The highest total (1310 m{sup 2} g{sup -1}) and micropore surface area values (1083 m{sup 2} g{sup -1}) were obtained by Nb incorporation. The micro- and mesopore dimensions of MCM-41 increased from 0.5 to 1.1 nm and from 2.5 to 2.8 nm, respectively, with metal incorporation. Low V/Si ratios and presence of Nb in the starting solution enhanced narrow mesopore size distribution. The pore dimension and wall thickness values estimated from nitrogen adsorption and X-ray diffraction methods were consistent with the corresponding values obtained using transmission electron microscopy.

  17. Estrogen receptor β inhibits estradiol-induced proliferation and migration of MCF-7 cells through regulation of mitofusin 2.

    Science.gov (United States)

    Ma, Li; Liu, Yueping; Geng, Cuizhi; Qi, Xiaowei; Jiang, Jun

    2013-06-01

    In the present study, we investigated whether estrogen receptor (ER) β affected the proliferation and migration of the human breast cancer cell line MCF-7 through regulation of mitofusin 2 (mfn2). A previous study reported that mfn2 may be regulated by ER through a non-classical pathway; in this pathway, the ER modulates the activities of other transcription factors by stabilizing their binding to DNA and/or recruiting coactivators to the complex. However, the previous study, unlike the study presented here, did not directly explore the interactions between ER and mfn2. Here, RT-PCR and western blot analysis were used to test the expression of mfn2 in MCF-7 cells after exposure to different doses of estradiol (E2). The ability of cells to proliferate and migrate was determined by MTT assay and a monolayer-wounding protocol, respectively. Finally, changes in MCF-7 cell biology after transfection with ERβ or mfn2 expression vectors were investigated, and the role of ERβ in mfn2 expression was also explored. Our results showed that E2 attenuated mfn2 expression in a dose-dependent manner, concomitant with the activation of proliferation and migration of MCF-7 cells. The mfn2 expression vector effectively suppressed E2-induced upregulation of PCNA and migration in MCF-7 cells. ERβ inhibited the E2-induced mfn2 downregulation that accompanied the inhibition of proliferation and migration in MCF-7 cells. Briefly, ERβ may inhibit E2-induced proliferation and migration of MCF-7 cells through regulation of mfn2.

  18. Synthesis of PdO/MCM-41 nanocomposites using trans-[PdCl2(PEt3)2] as the source of metal

    International Nuclear Information System (INIS)

    Hernandez-Pineda, Jessica; Rio, Jose Manuel del; Carreto, Enrique; Terres, Eduardo; Montoya, J. Asencion; Zuniga-Gonzalez, Maria de Jesus; Morgado, Jorge

    2009-01-01

    Three PdO/MCM-41 nanocomposites containing PdO species that are dispersed on an MCM-41 support have been prepared using trans-[PdCl 2 (PEt 3 ) 2 ] as the source of metal. Thermal gravimetric analysis of the decomposition of this complex in air reveals a remarkable mass loss of all nonmetallic elements centered at 300 deg. C. The materials were characterized with X-ray powder diffraction (XRPD), nitrogen sorption and TEM, which showed that the PdO nanoparticles were present inside the pores of MCM-41. XRPD analysis confirms formation of PdO (palladinite) nanocrystals, as the sole crystalline phase present in the nanocomposites.

  19. Carbon dioxide adsorption on micro-mesoporous composite materials of ZSM-12/MCM-48 type: The role of the contents of zeolite and functionalized amine

    Energy Technology Data Exchange (ETDEWEB)

    Santos, S.C.G. [Federal University of Sergipe, Materials Science and Engineering Postgraduate Program P" 2CEM, São Cristovão/SE (Brazil); Pedrosa, A.M.Garrido [Federal University of Sergipe, Departament of Chemistry (DQI), São Cristovão/SE (Brazil); Souza, M.J.B., E-mail: mjbsufs@gmail.com [Federal University of Sergipe, Department of Chemical Engineering (DEQ), Av. Marechal Rondon S/N, 49100-000, São Cristovão/SE (Brazil); Cecilia, J.A.; Rodríguez-Castellón, E. [University of Málaga, Department of Inorganic Chemistry, Crystallography and Mineralogy, Faculty of Sciences, 29071, Málaga (Spain)

    2015-10-15

    Highlights: • Synthesis of the micro-mesoporous composite materials of ZSM-12/MCM-48 type. • Application of these adsorbents in the carbon dioxide adsorption. • Effects of the contents of zeolite and amino group in the material surface on the CO{sub 2} capture efficiency. - Abstract: In this study ZSM-12/MCM-48 adsorbents have been synthesized at three ZSM-12 content, and also were functionalizated with amine groups by grafting. All the adsorbents synthesized were evaluated for CO{sub 2} capture. The X-ray diffraction analysis of the ZSM-12/MCM-48 composite showed the main characteristic peaks of ZSM-12 and MCM-48, and after the functionalization, the structure of MCM-48 on the composite impregnated was affected due amine presence. For the composites without amine, the ZSM-12 content was the factor determining in the adsorption capacity of CO{sub 2} and for the composites with amine the amount of amine was that influenced in the adsorption capacity.

  20. Carbon dioxide adsorption on micro-mesoporous composite materials of ZSM-12/MCM-48 type: The role of the contents of zeolite and functionalized amine

    International Nuclear Information System (INIS)

    2CEM, São Cristovão/SE (Brazil))" data-affiliation=" (Federal University of Sergipe, Materials Science and Engineering Postgraduate Program P2CEM, São Cristovão/SE (Brazil))" >Santos, S.C.G.; Pedrosa, A.M.Garrido; Souza, M.J.B.; Cecilia, J.A.; Rodríguez-Castellón, E.

    2015-01-01

    Highlights: • Synthesis of the micro-mesoporous composite materials of ZSM-12/MCM-48 type. • Application of these adsorbents in the carbon dioxide adsorption. • Effects of the contents of zeolite and amino group in the material surface on the CO 2 capture efficiency. - Abstract: In this study ZSM-12/MCM-48 adsorbents have been synthesized at three ZSM-12 content, and also were functionalizated with amine groups by grafting. All the adsorbents synthesized were evaluated for CO 2 capture. The X-ray diffraction analysis of the ZSM-12/MCM-48 composite showed the main characteristic peaks of ZSM-12 and MCM-48, and after the functionalization, the structure of MCM-48 on the composite impregnated was affected due amine presence. For the composites without amine, the ZSM-12 content was the factor determining in the adsorption capacity of CO 2 and for the composites with amine the amount of amine was that influenced in the adsorption capacity

  1. Immunoradiometric assay of a novel proliferation marker: tumour polypeptide specific antigen in breast cancer management in north India

    International Nuclear Information System (INIS)

    Phanna-Hazra, P.; Sharma, U.; Gupta, K.K.; Bhatnagar, V.; Idnani, R.; Gangwar, P.K.; Hazra, D.K.

    2004-01-01

    Tissue Polypeptide Specific Antigen (TPS) is a novel tumour marker defined by the monoclonal antibody M3 ,discovered by Bjorklund,which is claimed to be a proliferation marker, and belonging to the cytokeratin 8-18 family. M3 defines this antigen in particular out of a group of Tissue Polypeptide antigens (TPA) charecterised by the same Swedish group and was claimed to be a pancarcinoma antigen reportedly being elevated in several different cancers in the European literature.Pancarcinoma markers are of interest in relation to cancer detection as well as for assessing therapy and prognosis.Pancarcinoma antigens are also of interest for radiobioconjugate immunotargetting both for diagnosis as well as for therapy. There were no reports on this marker in an Indian population and therefore this study was initiated at two institutions in Meerut and Agra, both in the northern state of Uttar Pradesh. In addition to 250 healthy controls, 288 cases of breast cancer were studied .In addituion benign disorders were studied: breast fibroadenosis 16, breast fibro adenoma 5, breast abscess 4. TPS levels were determined by an immunoradiometric assay. In controls all but 4 had values less than 80 Units/1,the upper normal level quoted by Bjorklund.The relationship of the serum levels of the markers to histological grade and anatomical stage of the tumour were studied. In addition several of the cases underwent therapy with chemotherapy /radiotherapy/surgery or combinations thereof. The response to treatment during follow up was categorized as Complete emission(CR),Partial Remission (PR)Stable Disease(SD), Progressive Disease(PD)and recurrence (R) by the respective clinicians using standard criteria. In the cancer subjects there was a close correlation of TPS elevation with anatomical stage. 10 cases belonged to stage 1 with TPS levels 176.1+-103.94 Units/L ,61 to stage II(TPS levels 206.45 +-168.23).,79 to stage Ilia (TPS 251.5+-168.53),83 to stage IIIB (TPS 537.35+- 691.71),and 55

  2. Effect of MCM09, an active site-directed inhibitor of factor Xa, on B16-BL6 melanoma lung colonies in mice.

    Science.gov (United States)

    Rossi, C; Hess, S; Eckl, R W; di Lena, A; Bruno, A; Thomas, O; Poggi, A

    2006-03-01

    Treatment with anticoagulant drugs has shown potential inhibitory effect on tumor invasion, although the relationship with clotting inhibition was not clear. The aim of our study was to evaluate the potential antitumor activity of MCM09, a newly developed, active site-directed, small molecule inhibitor of factor Xa (FXa) [WO0216312], and to relate the findings to anticlotting potency. MCM09 (0.1-10 mg kg(-1)) or heparin (H; 10 mg kg(-1)) was injected intravenously (i.v.), with 5 x 10(4) B16-BL6 melanoma cells, in C57BL/6 mice. Mice were killed after 18 days, to count lung colonies. Ex vivo anticoagulant activity was measured by activated partial thromboplastin time (APTT) on mouse plasma. MCM09, a selective inhibitor of FXa (IC-50 = 2.4 nm against human FXa), inhibited in a dose-dependent manner B16-BL6 melanoma lung colonies in mice. Mean lung metastasis number was 20.9 +/- 4.8 in controls (n = 10), 1.2 +/- 0.4 in mice treated with H, 10 mg kg(-1) i.v. (P < 0.01), 0.9 +/- 0.3, 9.2 +/- 2.2 and 15.5 +/- 2.6 in mice treated with MCM09, at 10 (P < 0.01), 1 (P < 0.05) and 0.1 mg kg(-1) i.v. (ns), respectively. MCM09 (10 mg kg(-1) i.v.) significantly prolonged APTT (57.1 +/- 10.2 s) 30 min after i.v. injection when compared with controls (25.3 +/- 1.6 s; P < 0.05). Lung colonies were 74.2-72.6% reduced by MCM09 (10 mg kg(-1)) given 60 or 120 min before cells, but not by MCM09 given 60 min thereafter, suggesting a direct cell interaction as a mechanism underlying antitumor activity.

  3. Structure and thermal performance of poly(ethylene glycol) alkyl ether (Brij)/porous silica (MCM-41) composites as shape-stabilized phase change materials

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lingjian; Shi, Haifeng, E-mail: haifeng.shi@gmail.com; Li, Weiwei; Han, Xu; Zhang, Xingxiang, E-mail: zhangpolyu@gmail.com

    2013-10-20

    Graphical abstract: The maximum 50 wt% Brij58 is loaded into the porous MCM-41 networks, and a new peak at 18.8° in XRD patterns confirmed the changes of crystallization behavior of Brij58 against the bulk one. - Highlights: • Poly(ethylene glycol) hexadecyl ether and poly(ethylene glycol) octadecyl ether have the good thermal storage ability. • New peak at 18.8° proved the coexisted confined crystallization and nucleation-induced crystallization. • Poly(ethylene glycol) alkyl ether/MCM-41 PCMs exhibits the good thermal stability. - Abstract: A series of shape-stabilized phase change materials (PCMs), composed of poly(ethylene glycol) hexadecyl ether (Brij58) or poly(ethylene glycol) octadecyl ether (Brij76) and porous silica (MCM-41), were prepared by the physical mixing method. The structure, thermal stability, energy storage ability and crystallization behavior of these composites are deeply investigated and characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), wide-angle X-ray diffraction (WAXD) and thermogravimetric analysis (TGA). Obvious phase transition behavior and energy storage capability are observed for these Brij/MCM-41 composites, and the heat storage efficiency increased with the weight of Brij component. New peak at 18.8° demonstrated that the pore size and the surface adsorption ability of MCM-41 affect the crystallization behavior of Brij molecule. The crystalline structure and energy storage ability of these Brij/MCM-41 composites are discussed based on the crystallization process.

  4. Overexpressed ubiquitin ligase Cullin7 in breast cancer promotes cell proliferation and invasion via down-regulating p53

    International Nuclear Information System (INIS)

    Guo, Hongsheng; Wu, Fenping; Wang, Yan; Yan, Chong; Su, Wenmei

    2014-01-01

    Highlights: • Cullin7 is overexpressed in human breast cancer samples. • Cullin7 stimulated proliferation and invasion of breast cancer cells. • Inhibition of p53 contributes to Cullin7-induced proliferation and invasion. - Abstract: Ubiquitin ligase Cullin7 has been identified as an oncogene in some malignant diseases such as choriocarcinoma and neuroblastoma. However, the role of Cullin7 in breast cancer carcinogenesis remains unclear. In this study, we compared Cullin7 protein levels in breast cancer tissues with normal breast tissues and identified significantly higher expression of Cullin7 protein in breast cancer specimens. By overexpressing Cullin7 in breast cancer cells HCC1937, we found that Cullin7 could promote cell growth and invasion in vitro. In contrast, the cell growth and invasion was inhibited by silencing Cullin7 in breast cancer cell BT474. Moreover, we demonstrated that Cullin7 promoted breast cancer cell proliferation and invasion via down-regulating p53 expression. Thus, our study provided evidence that Cullin7 functions as a novel oncogene in breast cancer and may be a potential therapeutic target for breast cancer management

  5. Overexpressed ubiquitin ligase Cullin7 in breast cancer promotes cell proliferation and invasion via down-regulating p53

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Hongsheng [Department of Histology and Embryology, Guangdong Medical College, Dongguan 523808, Guangdong (China); Wu, Fenping [The 7th People’s Hospital of Chengdu, Chengdu 610041, Sichuan (China); Wang, Yan [The Second School of Clinical Medicine, Guangdong Medical College, Dongguan 523808, Guangdong (China); Yan, Chong [School of Pharmacy, Guangdong Medical College, Dongguan 523808, Guangdong (China); Su, Wenmei, E-mail: wenmeisutg@126.com [Oncology of Affiliated Hospital Guangdong Medical College, Zhanjiang 524000, Guangdong (China)

    2014-08-08

    Highlights: • Cullin7 is overexpressed in human breast cancer samples. • Cullin7 stimulated proliferation and invasion of breast cancer cells. • Inhibition of p53 contributes to Cullin7-induced proliferation and invasion. - Abstract: Ubiquitin ligase Cullin7 has been identified as an oncogene in some malignant diseases such as choriocarcinoma and neuroblastoma. However, the role of Cullin7 in breast cancer carcinogenesis remains unclear. In this study, we compared Cullin7 protein levels in breast cancer tissues with normal breast tissues and identified significantly higher expression of Cullin7 protein in breast cancer specimens. By overexpressing Cullin7 in breast cancer cells HCC1937, we found that Cullin7 could promote cell growth and invasion in vitro. In contrast, the cell growth and invasion was inhibited by silencing Cullin7 in breast cancer cell BT474. Moreover, we demonstrated that Cullin7 promoted breast cancer cell proliferation and invasion via down-regulating p53 expression. Thus, our study provided evidence that Cullin7 functions as a novel oncogene in breast cancer and may be a potential therapeutic target for breast cancer management.

  6. Grafting of [(64)Cu]-TPPF20 porphyrin complex on Functionalized nano-porous MCM-41 silica as a potential cancer imaging agent.

    Science.gov (United States)

    Fazaeli, Yousef; Feizi, Shahzad; Jalilian, Amir R; Hejrani, Ali

    2016-06-01

    Mesoporous silica, MCM-41, functionalized with 3-aminopropyltriethoxysilane (APTES) was investigated as a potential drug delivery system, using [(64)Cu]-5, 10, 15, 20-tetrakis penta fluorophenyl porphyrin complex. [(64)Cu]-TPPF20 complex was grafted on functionalized MCM-41. The product was characterized by paper chromatography, FTIR spectroscopy, low angle X-ray diffraction, CHN and TGA/DTA analyses and atomic force microscopy. The biological evaluations of the grafted complex, [(64)Cu]-TPPF20@NH2-MCM-41, were done in Fibrosarcoma tumor-bearing Sprague-Dawley rats using scarification studies and Sopha DST-XL Dual-Head SPECT system. The actual loading amount of aminopropyl groups was found about 1.6mmol per gram of final silica. The specific activity of the final compound was found to be 3Ci/g. Amine functionalized MCM-41 was found to be a good platform for theranostic radiopharmaceuticals such as copper-64 complexes. Considering the accumulation of the tracer in tumor cells, fast wash-out from normal tissues, the short half-life copper-64 and less imposed radiation doses to patients, [(64)Cu]-TPPF20@NH2-MCM-41 can potentially be a suitable candidate for tumor imaging applications and future PET studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Influence of incorporation method of sulfated zirconia in MCM-41 molecular sieve

    International Nuclear Information System (INIS)

    Pereira, C.E.; Santos, J.S.B.; Cavalcante, J.N.A.; Andrade, M.R.A.; Sousa, B.V.

    2016-01-01

    Sulfated metal oxides and sulfated zirconia have attracted great attention in recent years due to its high catalytic activity. The sulfated zirconia has the function of assigning the acidic material, through the formation of Bronsted acids and Lewis sites. The incorporation of sulfated zirconia in MCM-41 molecular sieve was carried out through the techniques: dry and wet. The wet process involves the use of an excess of solution on the volume of the support pores. Therefore, the concentration of the metal precursor on the support depends on the solution concentration and the pore volume of the support. In the process of incorporating by dry, the volume of the solution containing the precursor does not exceed the pore volume of the support. After either procedure, the impregnated support must be dried in order to allow the precursor compound can be converted into a catalytically active phase. This study aims to evaluate two methods of incorporation of sulfated zirconia in the mesoporous molecular sieve MCM-41. The process of merger took for wet and dry impregnation. Through the XRD patterns it was possible to identify the presence of the hexagonal structure of the molecular sieve, as well as the tetragonal and monoclinic phases of zirconia. From the spectroscopic analysis in the infrared region to the method the wet, it was possible to identify the vibrational frequencies related to the merger of sulfated zirconia in the MCM-41 structure of the molecular sieve. (author)

  8. Impact of partial sleep deprivation on immune markers.

    Science.gov (United States)

    Wilder-Smith, A; Mustafa, F B; Earnest, A; Gen, L; Macary, P A

    2013-10-01

    Sleep quality is considered to be an important predictor of immunity. Lack of sleep therefore may reduce immunity, thereby increasing the susceptibility to respiratory pathogens. A previous study showed that reduced sleep duration was associated with an increased likelihood of the common cold. It is important to understand the role of sleep in altering immune responses to understand how sleep deprivation leads to an increased susceptibility to the common cold or other respiratory infections. We sought to examine the impact of partial sleep deprivation on various immune markers. Fifty-two healthy volunteers were partially sleep deprived for one night. We took blood samples before the sleep deprivation, immediately after, and 4 and 7 days after sleep deprivation. We measured various immune markers and used a generalized estimating equation (GEE) to examine the differences in the repeated measures. CD4, CD8, CD14, and CD16 all showed significant time-dependent changes, but CD3 did not. The most striking time-dependent change was observed for the mitogen proliferation assay and for HLA-DR. There was a significant decrease in the mitogen proliferation values and HLA-DR immediately after the sleep deprivation experiment, which started to rise again on day 4 and normalized by day 7. The transiently impaired mitogen proliferation, the decreased HLA-DR, the upregulated CD14, and the variations in CD4 and CD8 that we observed in temporal relationship with partial sleep deprivation could be one possible explanation for the increased susceptibility to respiratory infections reported after reduced sleep duration. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Ck2-Dependent Phosphorylation Is Required to Maintain Pax7 Protein Levels in Proliferating Muscle Progenitors.

    Directory of Open Access Journals (Sweden)

    Natalia González

    Full Text Available Skeletal muscle regeneration and long term maintenance is directly link to the balance between self-renewal and differentiation of resident adult stem cells known as satellite cells. In turn, satellite cell fate is influenced by a functional interaction between the transcription factor Pax7 and members of the MyoD family of muscle regulatory factors. Thus, changes in the Pax7-to-MyoD protein ratio may act as a molecular rheostat fine-tuning acquisition of lineage identity while preventing precocious terminal differentiation. Pax7 is expressed in quiescent and proliferating satellite cells, while its levels decrease sharply in differentiating progenitors Pax7 is maintained in cells (reacquiring quiescence. While the mechanisms regulating Pax7 levels based on differentiation status are not well understood, we have recently described that Pax7 levels are directly regulated by the ubiquitin-ligase Nedd4, thus promoting proteasome-dependent Pax7 degradation in differentiating satellite cells. Here we show that Pax7 levels are maintained in proliferating muscle progenitors by a mechanism involving casein kinase 2-dependent Pax7 phosphorylation at S201. Point mutations preventing S201 phosphorylation or casein kinase 2 inhibition result in decreased Pax7 protein in proliferating muscle progenitors. Accordingly, this correlates directly with increased Pax7 ubiquitination. Finally, Pax7 down regulation induced by casein kinase 2 inhibition results in precocious myogenic induction, indicating early commitment to terminal differentiation. These observations highlight the critical role of post translational regulation of Pax7 as a molecular switch controlling muscle progenitor fate.

  10. Design of epoxy-functionalized Fe3O4@MCM-41 core-shell nanoparticles for enzyme immobilization.

    Science.gov (United States)

    Ulu, Ahmet; Ozcan, Imren; Koytepe, Suleyman; Ates, Burhan

    2018-05-01

    The scope of our research was to prepare the organosilane-modified Fe 3 O 4 @MCM-41 core-shell magnetic nanoparticles, used for L-ASNase immobilization and explored screening of immobilization conditions such as pH, temperature, thermal stability, kinetic parameters, reusability and storage stability. In this content, Fe 3 O 4 core-shell magnetic nanoparticles were prepared via co-precipitation method and coated with MCM-41. Then, Fe 3 O 4 @MCM-41 magnetic nanoparticles were functionalized by (3-glycidyloxypropyl) trimethoxysilane (GPTMS) as an organosilane compound. Subsequently, L-ASNase was covalently immobilized on epoxy-functionalized Fe 3 O 4 @MCM-41 magnetic nanoparticles. The immobilized L-ASNase had greater activity at high pH and temperature values. It also maintained >92% of the initial activity after incubation at 55 °C for 3 h. Regarding kinetic values, immobilized L-ASNase showed a higher Vmax and lower Km compared to native L-ASNase. In addition, it displayed excellent reusability for 12 successive cycles. After 30 days of storage at 4 °C and 25 °C, immobilized L-ASNase retained 54% and 26% of its initial activities while native L-ASNase lost about 68% and 84% of its initial activity, respectively. As a result, the immobilization of L-ASNase onto magnetic nanoparticles may provide an advantage in terms of removal of L-ASNase from reaction media. Copyright © 2018. Published by Elsevier B.V.

  11. Hydrothermal synthesis of meso porous silica MCM-41 using commercial sodium silicate

    Energy Technology Data Exchange (ETDEWEB)

    Melendez O, H. I.; Mercado S, A.; Garcia C, L. A.; Castruita, G.; Perera M, Y A., E-mail: ivan_melendez380@hotmail.com [Centro de Investigacion en Quimica Aplicada, Bldv. Enrique Reyna Hermosillo No. 140, Saltillo 25294, Coahuila (Mexico)

    2013-08-01

    In this work, ordered meso porous silica MCM-41 was prepared by hydrothermal synthesis using industrial-grade sodium silicate (Na{sub 2}SiO{sub 3}) as silica source, hexadecyltrimethyl-ammonium bromide (CTAB) as template agent and ethyl acetate as ph regulator. The influence of CTAB/SiO{sub 2} molar ratio, reaction time, aging temperature, and co-surfactant type on the structural and morphological properties of the obtained silica was studied. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption isotherms. Ordered meso porous MCM-41 silica was obtained at 80 C by using a range of CTAB/SiO{sub 2} molar ratio from 0.35 to 0.71 and reaction times up to 72 h and isopropanol (i-Pr OH) as co-surfactant. (Author)

  12. Standardizing evaluation of sarcoma proliferation- higher Ki-67 expression in the tumor periphery than the center

    DEFF Research Database (Denmark)

    Fernebro, J; Engellau, J; Persson, A

    2007-01-01

    Soft tissue sarcomas often present as large and histopathologically heterogenous tumors. Proliferation has repeatedly been identified as a prognostic factor and immunostaining for Ki-67 represents the most commonly used proliferation marker. There is, however, a lack of consensus on how to evaluate...... of proliferation in soft tissue sarcomas should be standardized for clinical application of Ki-67 as a prognostic marker....

  13. UTILIZATION OF RICE HUSK AS RAW MATERIAL IN SYNTHESIS OF MESOPOROUS SILICATES MCM-41

    Directory of Open Access Journals (Sweden)

    Suyanta Suyanta

    2011-12-01

    Full Text Available The research about synthesis and characterization of MCM-41 from rice husk has been done. Silica (SiO2 was extracted from rice husk by refluxing with 3M hydrochloric solution at 80 °C for 3 h. The acid-leached rice husk was filtered, washed, dried and calcined at 650 °C for 6 h lead the rough powder of rice husk silica with light brown in color. Characterization was carried out by X-ray diffraction (XRD and FTIR spectroscopy method. Rice husk silica was dissolved into the sodium hydroxide solution leading to the solution of sodium silicate, and used as silica source for the synthesis of MCM-41. MCM-41 was synthesized by hydrothermal process to the mixture prepared from 29 g of distilled water, 8.67 g of cetyltrimethyl ammonium bromide (CTMAB, 9.31 g of sodium silicate solution, and amount mL of 1 M H2SO4. Hydrothermal process was carried out at 100 °C in a teflon-lined stainless steel autoclave heated in the oven for 36 h. The solid phase was filtered, then washed with deionised water, and dried in the oven at 100 °C for 2 h. The surfactant CTMAB was removed by calcination at 550 °C for 10 h with heating rate 2 °C/min. The as-synthesized and calcined crystals were characterized by using FTIR spectroscopy, X-ray diffraction and N2 physisorption methods. In order to investigate the effect of silica source, the same procedure was carried out by using pure sodium silicate as silica source. It was concluded that silica extracted from rice husk can be used as raw materials in the synthesis of MCM-41, there is no significant difference in crystallinity and pore properties when was compared to material produced from commercial sodium silicate.

  14. A naringenin–tamoxifen combination impairs cell proliferation and survival of MCF-7 breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Hatkevich, Talia; Ramos, Joseph; Santos-Sanchez, Idalys; Patel, Yashomati M., E-mail: ympatel@uncg.edu

    2014-10-01

    Since over 60% of breast cancers are estrogen receptor positive (ER+), many therapies have targeted the ER. The ER is activated by both estrogen binding and phosphorylation. While anti-estrogen therapies, such as tamoxifen (Tam) have been successful they do not target the growth factor promoting phosphorylation of the ER. Other proliferation pathways such as the phosphatidylinositol-3 kinase, (PI3K) and the mitogen-activated protein kinase (MAPK) pathways are activated in breast cancer cells and are associated with poor prognosis. Thus targeting multiple cellular proliferation and survival pathways at the onset of treatment is critical for the development of more effective therapies. The grapefruit flavanone naringenin (Nar) is an inhibitor of both the PI3K and MAPK pathways. Previous studies examining either Nar or Tam used charcoal-stripped serum which removed estrogen as well as other factors. We wanted to use serum containing medium in order to retain all the potential inducers of cell proliferation so as not to exclude any targets of Nar. Here we show that a Nar–Tam combination is more effective than either Tam alone or Nar alone in MCF-7 breast cancer cells. We demonstrate that a Nar–Tam combination impaired cellular proliferation and viability to a greater extent than either component alone in MCF-7 cells. Furthermore, the use of a Nar–Tam combination requires lower concentrations of both compounds to achieve the same effects on proliferation and viability. Nar may function by inhibiting both PI3K and MAPK pathways as well as localizing ERα to the cytoplasm in MCF-7 cells. Our results demonstrate that a Nar–Tam combination induces apoptosis and impairs proliferation signaling to a greater extent than either compound alone. These studies provide critical information for understanding the molecular mechanisms involved in cell proliferation and apoptosis in breast cancer cells. - Highlights: • Nar–Tam impairs cell viability more effectively than

  15. A naringenin–tamoxifen combination impairs cell proliferation and survival of MCF-7 breast cancer cells

    International Nuclear Information System (INIS)

    Hatkevich, Talia; Ramos, Joseph; Santos-Sanchez, Idalys; Patel, Yashomati M.

    2014-01-01

    Since over 60% of breast cancers are estrogen receptor positive (ER+), many therapies have targeted the ER. The ER is activated by both estrogen binding and phosphorylation. While anti-estrogen therapies, such as tamoxifen (Tam) have been successful they do not target the growth factor promoting phosphorylation of the ER. Other proliferation pathways such as the phosphatidylinositol-3 kinase, (PI3K) and the mitogen-activated protein kinase (MAPK) pathways are activated in breast cancer cells and are associated with poor prognosis. Thus targeting multiple cellular proliferation and survival pathways at the onset of treatment is critical for the development of more effective therapies. The grapefruit flavanone naringenin (Nar) is an inhibitor of both the PI3K and MAPK pathways. Previous studies examining either Nar or Tam used charcoal-stripped serum which removed estrogen as well as other factors. We wanted to use serum containing medium in order to retain all the potential inducers of cell proliferation so as not to exclude any targets of Nar. Here we show that a Nar–Tam combination is more effective than either Tam alone or Nar alone in MCF-7 breast cancer cells. We demonstrate that a Nar–Tam combination impaired cellular proliferation and viability to a greater extent than either component alone in MCF-7 cells. Furthermore, the use of a Nar–Tam combination requires lower concentrations of both compounds to achieve the same effects on proliferation and viability. Nar may function by inhibiting both PI3K and MAPK pathways as well as localizing ERα to the cytoplasm in MCF-7 cells. Our results demonstrate that a Nar–Tam combination induces apoptosis and impairs proliferation signaling to a greater extent than either compound alone. These studies provide critical information for understanding the molecular mechanisms involved in cell proliferation and apoptosis in breast cancer cells. - Highlights: • Nar–Tam impairs cell viability more effectively than

  16. Testing an MCM for high-energy physics experiments a case study

    CERN Document Server

    Benso, A; Prinetto, P; Giovannetti, S; Mariani, R; Motto, S

    1999-01-01

    This paper presents the test strategy adopted at different hierarchical abstraction levels (from board to die level) during the development of a multichannel data acquisition and signal processing MCM, designed for the new generation experiments of high-energy physics on the Large Hadron Collider accelerator at CERN. (10 refs).

  17. TCF7L2 polymorphisms and inflammatory markers before and after treatment with fenofibrate

    Directory of Open Access Journals (Sweden)

    Kabagambe Edmond K

    2009-10-01

    Full Text Available Abstract Background Inflammation is implicated in causing diabetes. We tested whether transcription factor 7 like-2 (TCF7L2 gene polymorphisms (rs12255372 and rs7903146, consistently associated with type 2 diabetes, are associated with plasma concentrations of inflammatory markers before and after three weeks of daily treatment with fenofibrate. Methods Men and women in the Genetics of Lipid-Lowering Drugs and Diet Network study (n = 1025, age 49 ± 16 y were included. All participants suspended use of lipid-lowering drugs for three weeks and were then given 160 mg/day of fenofibrate for three weeks. Inflammatory markers and lipids were measured before and after fenofibrate. ANOVA was used to test for differences across TCF7L2 genotypes. Results Under the additive or dominant model, there were no significant differences (P > 0.05 in the concentrations of inflammatory markers (hsCRP, IL-2, IL-6, TNF-α and MCP-1 across TCF7L2 genotypes in the period before or after treatment. For both rs12255372 and rs7903146, homozygote T-allele carriers had significantly higher (P Conclusion Overall these data show no association between TCF7L2 polymorphisms and the inflammatory markers suggesting that the effects of TCF7L2 on diabetes may not be via inflammation.

  18. Cancer cell-associated cytoplasmic B7–H4 is induced by hypoxia through hypoxia-inducible factor-1α and promotes cancer cell proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, You-Kyoung [Department of Microbiology and Immunology, Inje University College of Medicine, Busan 614-735 (Korea, Republic of); Advanced Research Center for Multiple Myeloma, Inje University College of Medicine, Busan 614-735 (Korea, Republic of); Park, Sae-Gwang; Choi, Il-Whan [Department of Microbiology and Immunology, Inje University College of Medicine, Busan 614-735 (Korea, Republic of); Lee, Soo-Woong [Advanced Research Center for Multiple Myeloma, Inje University College of Medicine, Busan 614-735 (Korea, Republic of); Lee, Sang Min [Department of Internal Medicine, Division of Hematology/Oncology, Busan Paik Hospital, Inje University, Busan 614-735 (Korea, Republic of); Choi, Inhak, E-mail: miccih@inje.ac.kr [Department of Microbiology and Immunology, Inje University College of Medicine, Busan 614-735 (Korea, Republic of); Advanced Research Center for Multiple Myeloma, Inje University College of Medicine, Busan 614-735 (Korea, Republic of)

    2015-04-03

    Aberrant B7–H4 expression in cancer tissues serves as a novel prognostic biomarker for poor survival in patients with cancer. However, the factor(s) that induce cancer cell-associated B7–H4 remain to be fully elucidated. We herein demonstrate that hypoxia upregulates B7–H4 transcription in primary CD138{sup +} multiple myeloma cells and cancer cell lines. In support of this finding, analysis of the Multiple Myeloma Genomics Portal (MMGP) data set revealed a positive correlation between the mRNA expression levels of B7–H4 and the endogenous hypoxia marker carbonic anhydrogenase 9. Hypoxia-induced B7–H4 expression was detected in the cytoplasm, but not in cancer cell membranes. Chromatin immunoprecipitation analysis demonstrated binding of hypoxia-inducible factor-1α (HIF-1α) to proximal hypoxia-response element (HRE) sites within the B7–H4 promoter. Knockdown of HIF-1α and pharmacological inhibition of HIF-1α diminished B7–H4 expression. Furthermore, knockdown of cytoplasmic B7–H4 in MCF-7 decreased the S-phase cell population under hypoxia. Finally, MMGP analysis revealed a positive correlation between the transcript levels of B7–H4 and proliferation-related genes including MKI67, CCNA1, and Myc in several patients with multiple myeloma. Our results provide insight into the mechanisms underlying B7–H4 upregulation and its role in cancer cell proliferation in a hypoxic tumor microenvironment. - Highlights: • Hypoxia upregulates B7–H4 transcription and protein expression. • Hypoxia-induced B7–H4 is detected in the cytoplasm, but not on membrane. • ChIP assay reveals a binding of HIF-1α to B7–H4 promoter at HRE site. • Knockdown and pharmacological inhibition of HIF-1α reduce B7–H4 expression. • B7–H4 knockdown decrease the number of cells in S-phase of cell cycle.

  19. Characterization of Co and Fe-MCM-56 catalysts for NH3-SCR and N2O decomposition: An in situ FTIR study

    Science.gov (United States)

    Grzybek, Justyna; Gil, Barbara; Roth, Wieslaw J.; Skoczek, Monika; Kowalczyk, Andrzej; Chmielarz, Lucjan

    2018-05-01

    Two-step preparation of iron and cobalt-containing MCM-56 zeolites has been undertaken to evaluate the influence of their physicochemical properties in the selective catalytic reduction (NH3-SCR or DeNOx) of NO using NH3 as a reductant. Zeolites were prepared by the selective leaching of the framework cations by concentrated HNO3 solution and NH4F/HF mixture and consecutively, introduction of Co and Fe heteroatoms, in quantities below 1 wt%. Further calcination allowed to obtain highly dispersed active species. Their evaluation and speciation was realized by adsorption of pyridine and NO, followed by FTIR spectroscopy. Both Fe-MCM-56 zeolites showed excellent activities (maximum NO conversion 92%) with high selectivity to dinitrogen (above 99%) in the high temperature NH3-SCR process. High catalytic activity of Fe-MCM-56 zeolites was assigned to the formation of stable nitrates, delivering NO to react with NH3 at higher temperatures and suppressing the direct NO oxidation. It was found that more nitrates was formed in Fe-MCM-56 (HNO3) than in Fe-MCM-56 (HF/NH4F) and that could compensate for the lower Fe loading, resulting in very similar catalytic activity of both catalysts. At the same time both Co-and Fe-MCM-56 zeolites were moderately active in direct N2O decomposition, with maximum N2O conversion not higher than 80% and activity window starting at 500 °C. This phenomenon was expected since both types of catalysts contained well dispersed active centers, not beneficial for this reaction.

  20. Mesoporous MCM-41 embeded with Ru(II)-based chemosensor: Preparation, characterization, and emission variation towards pH

    International Nuclear Information System (INIS)

    Jingxia, Wang

    2014-01-01

    In this article, a pH sensing mesoporous MCM-41 material containing covalently bonded Ru(II) complex in the silicate network was prepared and named as Ru–MCM-41. The emission signal shows a tendency to decrease upon increasing pH values. The luminescent pH sensor can be explained by the protonation and deprotonation of the PIP ligand (PIP=2-phenyl-1H-imidazo[4,5-f][1,10]phenanthroline) and the fact that the mesoporousity of the MCM-41 matrix favors the –OH that diffused to the complex, resulting in quick emission quenching. It also shows a slight sensitivity towards dissolved molecular oxygen and varying temperatures, which, however, may not be too troublesome for actual applications. The sensing mechanism is also investigated. - Highlights: • An Ru complex was covalently grafted in mesoporous silicate network. • The emission signal decreased with increasing pH values. • The protonation and deprotonation of the ligand caused emission variation. • The emission was insensitive towards oxygen and temperature

  1. Rapamycin inhibits BMP-7-induced osteogenic and lipogenic marker expressions in fetal rat calvarial cells.

    Science.gov (United States)

    Yeh, Lee-Chuan C; Ma, Xiuye; Ford, Jeffery J; Adamo, Martin L; Lee, John C

    2013-08-01

    Bone morphogenetic proteins (BMPs) promote osteoblast differentiation and bone formation in vitro and in vivo. BMPs canonically signal through Smad transcription factors, but BMPs may activate signaling pathways traditionally stimulated by growth factor tyrosine kinase receptors. Of these, the mTOR pathway has received considerable attention because BMPs activate P70S6K, a downstream effector of mTOR, suggesting that BMP-induced osteogenesis is mediated by mTOR activation. However, contradictory effects of the mTOR inhibitor rapamycin (RAPA) on bone formation have been reported. Since bone formation is thought to be inversely related to lipid accumulation and mTOR is also important for lipid synthesis, we postulated that BMP-7 may stimulate lipogenic enzyme expression in a RAPA-sensitive mechanism. To test this hypothesis, we determined the effects of RAPA on BMP-7-stimulated expression of osteogenic and lipogenic markers in cultured fetal rat calvarial cells. Our study showed that BMP-7 promoted the expression of osteogenic and lipogenic markers. The effect of BMP-7 on osteogenic markers was greater in magnitude than on lipogenic markers and was temporally more sustained. RAPA inhibited basal and BMP-7-stimulated osteogenic and lipogenic marker expression and bone nodule mineralization. The acetyl CoA carboxylase inhibitor TOFA stimulated the expression of osteoblast differentiation markers, whereas palmitate suppressed their expression. We speculate that the BMP-7-stimulated adipogenesis is part of the normal anabolic response to BMPs, but that inappropriate activation of the lipid biosynthetic pathway by mTOR could have deleterious effects on bone formation and could explain paradoxical effects of RAPA to promote bone formation. Copyright © 2013 Wiley Periodicals, Inc.

  2. Swelling, Functionalization, and Structural Changes of the Nanoporous Layered Silicates AMH-3 and MCM-22

    KAUST Repository

    Kim, Wun-gwi

    2011-06-21

    Nanoporous layered silicate materials contain 2D-planar sheets of nanoscopic thickness and ordered porous structure. In comparison to porous 3D-framework materials such as zeolites, they have advantages such as significantly increased surface area and decreased diffusion limitations because the layers can potentially be exfoliated or intercalated into polymers to form nanocomposite materials. These properties are particularly interesting for applications as materials for enhancing molecular selectivity and throughput in composite membranes. In this report, the swelling and surface modification chemistry of two attractive nanoporous layered silicate materials, AMH-3 and MCM-22, were studied. We first describe a method, using long-chain diamines instead of monoamines, for swelling of AMH-3 while preserving its pore structure to a greater extent during the swelling process. Then, we describe a stepwise functionalization method for functionalizing the layer surfaces of AMH-3 and MCM-22 via silane condensation reactions. The covalently attached hydrocarbon chain molecules increased the hydrophobicity of AMH-3 and MCM-22 layer surfaces and therefore allow the possibility of effectively dispersing these materials in polymer matrices for thin film/membrane applications. © 2011 American Chemical Society.

  3. Ultrasonic-assisted synthesis of novel nanocomposite of poly(vinyl alcohol) and amino-modified MCM-41: A green adsorbent for Cd(II) removal.

    Science.gov (United States)

    Soltani, Roozbeh; Dinari, Mohammad; Mohammadnezhad, Gholamhossein

    2018-01-01

    Amino-modified MCM-41/poly(vinyl alcohol) nanocomposite (M-MCM-41/PVOH NC) was developed for the adsorption of Cd(II) from aqueous media. M-MCM-41/PVOH NC was prepared through ultrasonic-assisted and simple blending procedure with economical and environmentally friendly polymer. The as-prepared adsorbent was characterized by FT-IR, TEM, FE-SEM and TGA. The contact time, solution pH and initial concentration of Cd(II) were found to affect the adsorption of Cd(II) from aqueous media. Kinetic studies were carried out and pseudo-first-order (PFO), pseudo-second-order (PSO), Elovich, and intra-particle diffusion (IPD) reaction kinetic models were examined. The kinetic results revealed that the adsorption of Cd(II) onto M-MCM-41/PVOH NC followed PSO kinetic model and is a chemical adsorption. The equilibrium adsorption data were evaluated by different isotherms viz. Langmuir, Freundlich, and Dubinin Radushkevich (D-R) equations. The equilibrium data fitted better with the Langmuir isotherm and the maximum adsorption capacity of M-MCM-41/PVOH NC at 298K was calculated to be 46.73mgg -1 for Cd(II) on a typical saturated monomolecular layer with a fixed number of localized adsorption sites. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Novel acridone-modified MCM-41 type silica: Synthesis, characterization and fluorescence tuning

    Directory of Open Access Journals (Sweden)

    Maximilian Hemgesberg

    2011-06-01

    Full Text Available A Mobil Composition of Matter (MCM-41 type mesoporous silica material containing N-propylacridone groups has been successfully prepared by co-condensation of an appropriate organic precursor with tetraethyl orthosilicate (TEOS under alkaline sol–gel conditions. The resulting material was fully characterized by means of X-ray diffraction (XRD, N2-adsorption–desorption, transmission electron microscopy (TEM, IR and UV–vis spectroscopy, as well as 29Si and 13C CP-MAS NMR techniques. The material features a high inner surface area and a highly ordered two-dimensional hexagonal pore structure. The fluorescence properties of the organic chromophore can be tuned via complexation of its carbonyl group with scandium triflate, which makes the material a good candidate for solid state sensors and optics. The successful synthesis of highly ordered MCM materials through co-condensation was found to be dependent on the chemical interaction of the different precursors.

  5. Simultaneous efficient adsorption of Pb2+ and MnO4− ions by MCM-41 functionalized with amine and nitrilotriacetic acid anhydride

    International Nuclear Information System (INIS)

    Chen, Feiyun; Hong, Mingzhu; You, Weijie; Li, Chong; Yu, Yan

    2015-01-01

    Highlights: • MCM-41 was successfully modified with amine and nitrilotriacetic acid anhydride. • The adsorbent can simultaneously remove Pb 2+ and MnO 4 − by adjusting pH of the system. • The maximum adsorption capacities of Pb 2+ and MnO 4 − are 147 mg/g and 156 mg/g. • The absorbent exhibits good regeneration and reusability for 5 cycles use. - Abstract: A novel adsorbent NH 2 /MCM-41/NTAA, capable of simultaneous adsorption of cations and anions from aqueous solution, was prepared by immobilization of amine and nitrilotriacetic acid anhydride (NTAA) onto MCM-41. The structures and properties before and after surface modification were systematically investigated through X-ray diffraction (XRD), transmission electron microscope (TEM) and scanning electron microscope (SEM), nitrogen adsorption–desorption, and infrared spectroscopy (FTIR), thermogravimetry (TGA) and X-ray photoelectron spectroscopy (XPS). They together confirm that the amine and NTAA group were chemically bonded to the internal surface of the mesoporous. The NH 2 /MCM-41/NTAA were used to adsorb Pb 2+ and MnO 4 − in an aqueous solution in a batch system, and the maximum adsorption efficiency was found to occur at pH 5.0 and 3.0, respectively. NH 2 /MCM-41/NTAA exhibit preferable removal of Pb 2+ through electrostatic interactions and chelation, whereas it captures MnO 4 − by means of electrostatic interactions. The experimental data are fitted the Langmuir isotherm model reasonably well, with the maximum adsorption capacity of 147 mg/g for Pb 2+ and of 156 mg/g for MnO 4 − . The adsorption rates of both Pb 2+ and MnO 4 − are found to follow the pseudo-second order kinetics. Furthermore, the NH 2 /MCM-41/NTAA adsorbent performs good recyclability and reusability for 5 cycles use. This study indicates a potential applicability of NH 2 /MCM-41/NTAA as new absorbents for effective simultaneous adsorption of hazardous metal ions and anions from wastewater.

  6. The MADS-box transcription factor FgMcm1 regulates cell identity and fungal development in Fusarium graminearum.

    Science.gov (United States)

    Yang, Cui; Liu, Huiquan; Li, Guotian; Liu, Meigang; Yun, Yingzi; Wang, Chenfang; Ma, Zhonghua; Xu, Jin-Rong

    2015-08-01

    In eukaryotic cells, MADS-box genes are known to play major regulatory roles in various biological processes by combinatorial interactions with other transcription factors. In this study, we functionally characterized the FgMCM1 MADS-box gene in Fusarium graminearum, the causal agent of wheat and barley head blight. Deletion of FgMCM1 resulted in the loss of perithecium production and phialide formation. The Fgmcm1 mutant was significantly reduced in virulence, deoxynivalenol biosynthesis and conidiation. In yeast two-hybrid assays, FgMcm1 interacted with Mat1-1-1 and Fst12, two transcription factors important for sexual reproduction. Whereas Fgmcm1 mutants were unstable and produced stunted subcultures, Fgmcm1 mat1-1-1 but not Fgmcm1 fst12 double mutants were stable. Furthermore, spontaneous suppressor mutations occurred frequently in stunted subcultures to recover growth rate. Ribonucleic acid sequencing analysis indicated that a number of sexual reproduction-related genes were upregulated in stunted subcultures compared with the Fgmcm1 mutant, which was downregulated in the expression of genes involved in pathogenesis, secondary metabolism and conidiation. We also showed that culture instability was not observed in the Fvmcm1 mutants of the heterothallic Fusarium verticillioides. Overall, our data indicate that FgMcm1 plays a critical role in the regulation of cell identity, sexual and asexual reproduction, secondary metabolism and pathogenesis in F. graminearum. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  7. A Cu/Al-MCM-41 mesoporous molecular sieve: application in the abatement of no in exhaust gases

    Directory of Open Access Journals (Sweden)

    M. S. Batista

    2005-09-01

    Full Text Available Propane oxidation and reduction of NO to N2 with propane under oxidative conditions on a Cu-Al-MCM-41 mesoporous molecular sieve and Cu-ZSM-5 zeolites were studied. Both types of catalysts were prepared by ion exchange in aqueous solutions of copper acetate and characterised by X-ray diffraction (XRD, nitrogen sorption measurement, diffuse reflectance ultra-violet spectroscopy (DRS-UV, diffuse reflectance infra-red Fourier transform spectroscopy (DRIFTS of the adsorption of CO on Cu+ and temperature-programmed reduction with hydrogen (H2-TPR. The NO reduction was performed between 200 and 500 ºC using a GHSV = 42,000 h-1. H2-TPR data showed that in the prepared Cu-Al-MCM-41 all the Cu atoms are on the surface of the mesopores as highly dispersed CuO, which results in a decrease in specific surface area and in mesopore volume. H2-TPR together with DRIFTS data provided evidence that in Cu/ZSM-5 catalysts, Cu atoms are found as two different Cu2+ cations: Cualpha2+ and Cubeta2+, which are located on charge compensation sites, and their thermo-redox properties were different from those of Cu atoms in Cu-Al-MCM-41. The specific activity of the Cu2+ exchangeable cations in Cu-ZSM-5, irrespective of their nature, was much greater than that of the Cu2+ in Cu-Al-MCM-41, where they are found as CuO.

  8. Development and chamber evaluation of the MCM v3.2 degradation scheme for β-caryophyllene

    Directory of Open Access Journals (Sweden)

    M. E. Jenkin

    2012-06-01

    Full Text Available A degradation mechanism for β-caryophyllene has recently been released as part of version 3.2 of the Master Chemical Mechanism (MCM v3.2, describing the gas phase oxidation initiated by reaction with ozone, OH radicals and NO3 radicals. A detailed overview of the construction methodology is given, within the context of reported experimental and theoretical mechanistic appraisals. The performance of the mechanism has been evaluated in chamber simulations in which the gas phase chemistry was coupled to a representation of the gas-to-aerosol partitioning of 280 multi-functional oxidation products. This evaluation exercise considered data from a number of chamber studies of either the ozonolysis of β-caryophyllene, or the photo-oxidation of β-caryophyllene/NOx mixtures, in which detailed product distributions have been reported. This includes the results of a series of photo-oxidation experiments performed in the University of Manchester aerosol chamber, also reported here, in which a comprehensive characterization of the temporal evolution of the organic product distribution in the gas phase was carried out, using Chemical Ionisation Reaction Time-of-Flight Mass Spectrometry (CIR-TOF-MS, in conjunction with measurements of NOx, O3 and SOA mass loading. The CIR-TOF-MS measurements allowed approximately 45 time-resolved product ion signals to be detected, which were assigned on the basis of the simulated temporal profiles of the more abundant MCM v3.2 species, and their probable fragmentation patterns. The evaluation studies demonstrate that the MCM v3.2 mechanism provides an acceptable description of β-caryophyllene degradation under the chamber conditions considered, with the temporal evolution of the observables identified above generally being recreated within the uncertainty bounds of key parameters within the mechanism. The studies have highlighted a number of areas of uncertainty or discrepancy

  9. Heterogenic expression of stem cell markers in patient-derived glioblastoma spheroid cultures exposed to long-term hypoxia

    DEFF Research Database (Denmark)

    Rosenberg, Tine; Aaberg-Jessen, Charlotte; Petterson, Stine Asferg

    2018-01-01

    AIM: To investigate the time profile of hypoxia and stem cell markers in glioblastoma spheroids of known molecular subtype. MATERIALS & METHODS: Patient-derived glioblastoma spheroids were cultured up to 7 days in either 2% or 21% oxygen. Levels of proliferation (Ki-67), hypoxia (HIF-1α, CA9...

  10. Experimental study of polyethylene pyrolysis and combustion over HZSM-5, HUSY, and MCM-41.

    Science.gov (United States)

    Huang, Que; Liu, Changcheng; Wei, Ruichao; Wang, Jian

    2017-07-05

    The effects of temperatures, catalysts, and catalyst contents on polyethylene (PE) pyrolysis were investigated by using single-photon ionization time-of-flight mass spectrometry (SPI-TOFMS). The mass spectra of pyrolyzed PE and PE/catalysts from 300°C to 800°C illustrate that the pyrolysis reactions were apparently promoted and varied by introducing HZSM-5, HUSY, and MCM-41. As microporous catalysts, HZSM-5 and HUSY were found to accelerate the BTX formation at 400°C, which could not be observed for pure PE until 800°C. With the existence of MCM-41, only alkenes were produced below 600°C. The pyrolysis processes could to be accelerated by adding catalysts. Principal components analysis (PCA) was finally employed to identify the main factors with influence on the products distribution. Analytical results showed that the yield of the majority of products could be affected by different experimental conditions, that the type of catalysts makes the most significant influence. The impact of different types of catalysts on fire hazard of PE was studied by using the cone calorimeter. The results indicated that the time to ignition (TTI) and the peak heat release rate (pHRR) were changed remarkably. It is worth noting that with the addition of MCM-41, the pHRR is the minimum. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Photocatalytic removal of Congo red dye using MCM-48/Ni2O3 composite synthesized based on silica gel extracted from rice husk ash; fabrication and application.

    Science.gov (United States)

    Shaban, Mohamed; Abukhadra, Mostafa R; Hamd, Ahmed; Amin, Ragab R; Abdel Khalek, Ahmed

    2017-12-15

    MCM-48 mesoporous silica was successfully synthesized from silica gel extracted from rice husk ash and loaded by nickel oxide (Ni 2 O 3 ). The resulted composite was characterized using X-ray diffraction, scanning electron microscope, and UV-vis spectrophotometer. The role of MCM-48 as catalyst support in enhancing the photocatalytic properties of nickel oxide was evaluated through the photocatalytic degradation of Congo red dye under visible light source. MCM-48 as catalyst support for Ni 2 O 3 shows considerable enhancement in the adsorption capacity by 17% and 29% higher than the adsorption capacity of MCM-48 and Ni 2 O 3 , respectively. Additionally, the photocatalytic degradation percentage increased by about 64% relative to the degradation percentage using Ni 2 O 3 as a single component. The adsorption mechanism of MCM-48/Ni 2 O 3 is chemisorption process of multilayer form. The using of MCM-48 as catalyst support for Ni 2 O 3 enhanced the adsorption capacity and the photocatalytic degradation through increasing the surface area and prevents the nickel oxide particles from agglomeration. This was done through fixing nickel oxide particles throughout the porous structure which providing more exposed active adsorption sites and active photocatalyst sites for the incident photons. Based on the obtained results, supporting of nickel oxide particles onto MCM-48 are promising active centers for the degradation of Congo red dye molecules. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Sn-MCM-41 as Efficient Catalyst for the Conversion of Glucose into 5-Hydroxymethylfurfural in Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Qing Xu

    2013-11-01

    Full Text Available Recently, much attention has been paid to the development of technologies that facilitate the conversion of biomass into platform chemicals such as 5-hydroxymethylfurfural (5-HMF. In this paper, a tin-containing silica molecular sieve (Sn-MCM-41 was found to act as a bifunctional heterogeneous catalyst for the efficient conversion of glucose into 5-HMF in ionic liquid. In the presence of [EMIM]Br, the yield of 5-HMF converted from glucose reached 70% at 110 °C after 4 h. During the reaction, the active center of the catalyst first catalyzed the isomerization of glucose into fructose and then the dehydration of fructose into 5-HMF. After the reaction, the heterogeneous catalyst Sn-MCM-41 could be easily recovered and reused without a significant loss in activity. The catalyst Sn-MCM-41 was also able to catalyze the conversion of fructose into 5-HMF at an 80% yield. Moreover, the low toxicity of the Sn-based catalyst makes the method a greener approach for the conversion of saccharides into 5-HMF.

  13. Preparation of chitosan/MCM-41-PAA nanocomposites and the adsorption behaviour of Hg(II) ions

    Science.gov (United States)

    Fu, Yong; Huang, Yue; Hu, Jianshe

    2018-03-01

    A novel functional hybrid mesoporous composite material (CMP) based on chitosan and MCM-41-PAA was reported and its application as an excellent adsorbent for Hg(II) ions was also investigated. Innovatively, MCM-41-PAA was prepared by using diatomite and polyacrylic acid (PAA) with integrated polymer-silica hybrid frameworks, and then CMP was fabricated by introducing MCM-41-PAA to chitosan using glutaraldehyde as a cross-linking agent. The structure and morphology of CMP were characterized by X-ray diffraction, Fourier transform infrared spectra, thermogravimetric analysis, scanning electron microscopy and Brunauer-Emmett-Teller measurements. The results showed that the CMP possessed multifunctional groups such as -OH, -COOH and -NH2 with large specific surface area. Adsorption behaviour of Hg(II) ions onto CMP was fitted better by the pseudo-second-order kinetic model and the Langmuir model when the initial Hg(II) concentration, pH, adsorption temperature and time were 200 mg l-1, 4, 298 K and 120 min, respectively, as the optimum conditions. The corresponding maximum adsorption capacity could reach 164 mg g-1. According to the thermodynamic parameters determined such as free energy, enthalpy and entropy, the adsorption process of Hg(II) ions was spontaneous endothermic adsorption.

  14. Preparation of chitosan/MCM-41-PAA nanocomposites and the adsorption behaviour of Hg(II) ions

    Science.gov (United States)

    Fu, Yong; Huang, Yue; Hu, Jianshe

    2018-01-01

    A novel functional hybrid mesoporous composite material (CMP) based on chitosan and MCM-41-PAA was reported and its application as an excellent adsorbent for Hg(II) ions was also investigated. Innovatively, MCM-41-PAA was prepared by using diatomite and polyacrylic acid (PAA) with integrated polymer–silica hybrid frameworks, and then CMP was fabricated by introducing MCM-41-PAA to chitosan using glutaraldehyde as a cross-linking agent. The structure and morphology of CMP were characterized by X-ray diffraction, Fourier transform infrared spectra, thermogravimetric analysis, scanning electron microscopy and Brunauer–Emmett–Teller measurements. The results showed that the CMP possessed multifunctional groups such as –OH, –COOH and –NH2 with large specific surface area. Adsorption behaviour of Hg(II) ions onto CMP was fitted better by the pseudo-second-order kinetic model and the Langmuir model when the initial Hg(II) concentration, pH, adsorption temperature and time were 200 mg l−1, 4, 298 K and 120 min, respectively, as the optimum conditions. The corresponding maximum adsorption capacity could reach 164 mg g−1. According to the thermodynamic parameters determined such as free energy, enthalpy and entropy, the adsorption process of Hg(II) ions was spontaneous endothermic adsorption. PMID:29657793

  15. The Interaction between Checkpoint Kinase 1 (Chk1) and the Minichromosome Maintenance (MCM) Complex Is Required for DNA Damage-induced Chk1 Phosphorylation*

    Science.gov (United States)

    Han, Xiangzi; Aslanian, Aaron; Fu, Kang; Tsuji, Toshiya; Zhang, Youwei

    2014-01-01

    Chk1 is an essential mediator of the DNA damage response and cell cycle checkpoint. However, how exactly Chk1 transduces the checkpoint signaling is not fully understood. Here we report the identification of the heterohexamic minichromosome maintenance (MCM) complex that interacts with Chk1 by mass spectrometry. The interaction between Chk1 and the MCM complex was reduced by DNA damage treatment. We show that the MCM complex, at least partially, contributes to the chromatin association of Chk1, allowing for immediate phosphorylation of Chk1 by ataxia telangiectasia mutated and Rad3-related (ATR) in the presence of DNA damage. Further, phosphorylation of Chk1 at ATR sites reduces the interaction between Chk1 and the MCM complex, facilitating chromatin release of phosphorylated Chk1, a critical step in the initiation and amplification of cell cycle checkpoint. Together, these data provide novel insights into the activation of Chk1 in response to DNA damage. PMID:25049228

  16. Magnetic Fe3O4@MCM-41 core-shell nanoparticles functionalized with thiol silane for efficient l-asparaginase immobilization.

    Science.gov (United States)

    Ulu, Ahmet; Noma, Samir Abbas Ali; Koytepe, Suleyman; Ates, Burhan

    2018-06-06

    l-Asparaginase (l-ASNase) is a vital enzyme for medical treatment and food industry. Here, we assessed the use of Fe 3 O 4 @Mobil Composition of Matter No. 41 (MCM-41) magnetic nanoparticles as carrier matrix for l-ASNase immobilization. In addition, surface of Fe 3 O 4 @MCM-41 magnetic nanoparticles was functionalized with 3-mercaptopropyltrimethoxysilane (MPTMS) to enhance stability of l-ASNase. The chemical structure, thermal properties, magnetic profile and morphology of the thiol-functionalized Fe 3 O 4 @MCM-41 magnetic nanoparticles were characterized with Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential thermal analysis (DTA), differential scanning calorimetry (DSC), vibrating sample magnetometer (VSM), scanning electron microscope (SEM), energy dispersive X-ray (EDX) spectroscopy and zeta-potential measurement. l-ASNase was covalently immobilized onto the thiol-functionalized Fe 3 O 4 @MCM-41 magnetic nanoparticles. The properties of the immobilized enzyme, including optimum pH, temperature, kinetic parameters, thermal stability, reusability and storage stability were investigated and compared to free one. Immobilized enzyme was found to be stable over a wide range of pH and temperature range than free enzyme. The immobilized l-ASNase also showed higher thermal stability after 180 min incubation at 50 °C. The immobilized enzyme still retained 63% of its original activity after 16 times of reuse. The Km value for the immobilized enzyme was 1.15-fold lower than the free enzyme, which indicates increased affinity for the substrate. Additionally, the immobilized enzyme was active over 65% and 53% after 30 days of storage at 4 °C and room temperature (∼25 °C), respectively. Thereby, the results confirmed that thiol-functionalized Fe 3 O 4 @MCM-41 magnetic nanoparticles had high efficiency for l-ASNase immobilization and improved stability of L-ASNase.

  17. Efeito de diferentes fontes de sílica nos parâmetros texturais da peneira molecular MCM-41

    Directory of Open Access Journals (Sweden)

    M. S. B. Fontes

    2016-03-01

    Full Text Available Resumo Nas últimas décadas, pesquisas estão sendo desenvolvidas para obtenção de materiais eficientes e economicamente viáveis para aplicação em diversos setores da indústria. Os materiais mesoporosos da família MCM-41 estão entre os candidatos eficazes pela facilidade de síntese e estrutura que favorece uma gama de aplicações. O objetivo desse trabalho foi apresentar uma abordagem rítica das características e propriedades dos materiais mesoporosos do tipo MCM-41, enfocando nos aspectos estruturais. Além isso, foram discutidas as vantagens e desvantagens do uso de sílica comerciais e alternativas. As fontes de sílica comerciais analisadas foram sílica gel e TEOS; já as fontes de sílica alternativas foram cinza da casca de arroz, quartzo e pó de vidro. Os materiais analisados foram sintetizados pelo método hidrotérmico e caracterizados por DRX, FTIR, BET e TG. Os resultados apresentados comprovam a eficiência das fontes de sílica alternativas na síntese do MCM-41, pois os materiais apresentaram propriedades texturais dentro dos padrões exigidos. Dessa forma, eles estão aptos a serem testados na indústria em substituição aos MCM-41 sintetizados com fonte de sílica comercial.

  18. Comparison of the precision of two standardized co-ordinate systems for the quantitation of brain anatomy: preliminary results.

    Science.gov (United States)

    Sandor, T; Tieman, J; Ong, H T; Moss, M B; Jolesz, F; Albert, M

    1994-10-01

    We assessed reproducible definition of two standardized co-ordinate systems for intersubject analysis of brain images. The baselines in the two co-ordinate systems were a modification of the canthomeatal (mCM) line and the anterior-posterior commissural (AC-PC) line. Axial spin-echo MR images of four subjects at 1.5T were used. Operator error was computed from the replicate analyses of two operators. The mCM line was determined by the lens of the eye and the internal auditory canal, and the AC-PC line was determined by the intersection of AC and PC with the interhemispheric fissure. Reproducibility of the mCM markers (SD = 0.59 mm) did not differ significantly from that of the AC-PC line (SD = 0.68 mm). The measurement error of the angle of the baseline (delta alpha), however, was more than 7 times as large for the AC-PC line as for the mCM line. An additional error affecting the rostrocaudal rotation of the co-ordinate systems, attributable to the distance between the anatomic markers, was 2.1 and 3.6 degrees (3 mm and 5 mm slice thickness) for the mCM co-ordinate system and 8.2 and 11.0 degrees (3 mm and 5 mm slice thickness) for the AC-PC system. The AC-PC line based co-ordinate system is therefore, less reproducible than the mCM line based system. This could be improved if a combination of axial and sagittal images were used for the definition of the AC-PC line.

  19. Manganese porphyrin immobilized on magnetic MCM-41 nanoparticles as an efficient and reusable catalyst for alkene oxidations with sodium periodate

    Science.gov (United States)

    Hajian, Robabeh; Ehsanikhah, Amin

    2018-01-01

    This study describes the immobilization of tetraphenylporphyrinatomanganese(III) chloride, (MnPor), onto imidazole functionalized MCM-41 with magnetite nanoparticle core (Fe3O4@MCM-41-Im). The resultant material (Fe3O4@MCM-41-Im@MnPor) was characterized by X-ray diffractometry (XRD), Fourier transform infra-red (FT-IR), diffuse reflectance UV-Vis spectrophotometry (DR UV-Vis), field emission scanning electron microscopy (FESEM), Inductively coupled plasma (ICP), analyzer transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) surface area. This new heterogenized catalyst was applied as an efficient catalyst for the epoxidation of a variety of cyclic and linear olefins with NaIO4 under mild conditions. The prepared catalyst can be easily recovered through the application of an external magnet, and reused several times without any significant decrease in activity and magnetic properties.

  20. OX40 and IL-7 play synergistic roles in the homeostatic proliferation of effector memory CD4⁺ T cells.

    Science.gov (United States)

    Yamaki, Satoshi; Ine, Shouji; Kawabe, Takeshi; Okuyama, Yuko; Suzuki, Nobu; Soroosh, Pejman; Mousavi, Seyed Fazlollah; Nagashima, Hiroyuki; Sun, Shu-lan; So, Takanori; Sasaki, Takeshi; Harigae, Hideo; Sugamura, Kazuo; Kudo, Hironori; Wada, Motoshi; Nio, Masaki; Ishii, Naoto

    2014-10-01

    T-cell homeostasis preserves the numbers, the diversity and functional competence of different T-cell subsets that are required for adaptive immunity. Naïve CD4(+) T (TN ) cells are maintained in the periphery via the common γ-chain family cytokine IL-7 and weak antigenic signals. However, it is not clear how memory CD4(+) T-cell subsets are maintained in the periphery and which factors are responsible for the maintenance. To examine the homeostatic mechanisms, CFSE-labeled CD4(+) CD44(high) CD62L(low) effector memory T (TEM ) cells were transferred into sublethally-irradiated syngeneic C57BL/6 mice, and the systemic cell proliferative responses, which can be divided distinctively into fast and slow proliferations, were assessed by CFSE dye dilution. We found that the fast homeostatic proliferation of TEM cells was strictly regulated by both antigen and OX40 costimulatory signals and that the slow proliferation was dependent on IL-7. The simultaneous blockade of both OX40 and IL-7 signaling completely inhibited the both fast and slow proliferation. The antigen- and OX40-dependent fast proliferation preferentially expanded IL-17-producing helper T cells (Th17 cells). Thus, OX40 and IL-7 play synergistic, but distinct roles in the homeostatic proliferation of CD4(+) TEM cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. A STE12 homologue of the homothallic ascomycete Sordaria macrospora interacts with the MADS box protein MCM1 and is required for ascosporogenesis.

    Science.gov (United States)

    Nolting, Nicole; Pöggeler, Stefanie

    2006-11-01

    The MADS box protein MCM1 controls diverse developmental processes and is essential for fruiting body formation in the homothallic ascomycete Sordaria macrospora. MADS box proteins derive their regulatory specificity from a wide range of different protein interactions. We have recently shown that the S. macrospora MCM1 is able to interact with the alpha-domain mating-type protein SMTA-1. To further evaluate the functional roles of MCM1, we used the yeast two-hybrid approach to identify MCM1-interacting proteins. From this screen, we isolated a protein with a putative N-terminal homeodomain and C-terminal C2/H2-Zn2+ finger domains. The protein is a member of the highly conserved fungal STE12 transcription factor family of proteins and was therefore termed STE12. Furthermore, we demonstrate by means of two-hybrid and far western analysis that in addition to MCM1, the S. macrospora STE12 protein is able to interact with the mating-type protein SMTA-1. Unlike the situation in the closely related heterothallic ascomycete Neurospora crassa, deletion (Delta) of the ste12 gene in S. macrospora neither affects vegetative growth nor fruiting body formation. However, ascus and ascospore development are highly impaired by the Deltaste12 mutation. Our data provide another example of the functional divergence within the fungal STE12 transcription factor family.

  2. TSA suppresses miR-106b-93-25 cluster expression through downregulation of MYC and inhibits proliferation and induces apoptosis in human EMC.

    Science.gov (United States)

    Zhao, Zhi-Ning; Bai, Jiu-Xu; Zhou, Qiang; Yan, Bo; Qin, Wei-Wei; Jia, Lin-Tao; Meng, Yan-Ling; Jin, Bo-Quan; Yao, Li-Bo; Wang, Tao; Yang, An-Gang

    2012-01-01

    Histone deacetylase (HDAC) inhibitors are emerging as a novel class of anti-tumor agents and have manifested the ability to decrease proliferation and increase apoptosis in different cancer cells. A significant number of genes have been identified as potential effectors responsible for the anti-tumor function of HDAC inhibitor. However, the molecular mechanisms of these HDAC inhibitors in this process remain largely undefined. In the current study, we searched for microRNAs (miRs) that were affected by HDAC inhibitor trichostatin (TSA) and investigated their effects in endometrial cancer (EMC) cells. Our data showed that TSA significantly inhibited the growth of EMC cells and induced their apoptosis. Among the miRNAs that altered in the presence of TSA, the miR-106b-93-25 cluster, together with its host gene MCM7, were obviously down-regulated in EMC cells. p21 and BIM, which were identified as target genes of miR-106b-93-25 cluster, increased in TSA treated tumor cells and were responsible for cell cycle arrest and apoptosis. We further identified MYC as a regulator of miR-106b-93-25 cluster and demonstrated its down-regulation in the presence of TSA resulted in the reduction of miR-106b-93-25 cluster and up-regulation of p21 and BIM. More important, we found miR-106b-93-25 cluster was up-regulated in clinical EMC samples in association with the overexpression of MCM7 and MYC and the down-regulation of p21 and BIM. Thus our studies strongly indicated TSA inhibited EMC cell growth and induced cell apoptosis and cell cycle arrest at least partially through the down-regulation of the miR-106b-93-25 cluster and up-regulation of it's target genes p21 and BIM via MYC.

  3. Long-term omega-3 supplementation modulates behavior, hippocampal fatty acid concentration, neuronal progenitor proliferation and central TNF-α expression in 7 month old unchallenged mice

    Science.gov (United States)

    Grundy, Trent; Toben, Catherine; Jaehne, Emily J.; Corrigan, Frances; Baune, Bernhard T.

    2014-01-01

    Dietary polyunsaturated fatty acid (PUFA) manipulation is being investigated as a potential therapeutic supplement to reduce the risk of developing age-related cognitive decline (ARCD). Animal studies suggest that high omega (Ω)-3 and low Ω-6 dietary content reduces cognitive decline by decreasing central nervous system (CNS) inflammation and modifying neuroimmune activity. However, no previous studies have investigated the long term effects of Ω-3 and Ω-6 dietary levels in healthy aging mice leaving the important question about the preventive effects of Ω-3 and Ω-6 on behavior and underlying molecular pathways unaddressed. We aimed to investigate the efficacy of long-term Ω-3 and Ω-6 PUFA dietary supplementation in mature adult C57BL/6 mice. We measured the effect of low, medium, and high Ω-3:Ω-6 dietary ratio, given from the age of 3–7 months, on anxiety and cognition-like behavior, hippocampal tissue expression of TNF-α, markers of neuronal progenitor proliferation and gliogenesis and serum cytokine concentration. Our results show that a higher Ω-3:Ω-6 PUFA diet ratio increased hippocampal PUFA, increased anxiety, improved hippocampal dependent spatial memory and reduced hippocampal TNF-α levels compared to a low Ω-3:Ω-6 diet. Furthermore, serum TNF-α concentration was reduced in the higher Ω-3:Ω-6 PUFA ratio supplementation group while expression of the neuronal progenitor proliferation markers KI67 and doublecortin (DCX) was increased in the dentate gyrus as opposed to the low Ω-3:Ω-6 group. Conversely, Ω-3:Ω-6 dietary PUFA ratio had no significant effect on astrocyte or microglia number or cell death in the dentate gyrus. These results suggest that supplementation of PUFAs may delay aging effects on cognitive function in unchallenged mature adult C57BL/6 mice. This effect is possibly induced by increasing neuronal progenitor proliferation and reducing TNF-α. PMID:25484856

  4. Expressão de marcadores de proliferação celular e apoptose em carcinoma basocelular Markers expression of cell proliferation and apoptosis in basal cell carcinoma

    Directory of Open Access Journals (Sweden)

    Marília de Pádua Dornelas Corrêa

    2009-12-01

    Full Text Available FUNDAMENTOS: O carcinoma basocelular é o câncer mais comum em humanos. Estudos que utilizam recursos da biologia molecular e genética, associados à histomorfologia, permitem a identificação de fatores de risco no desenvolvimento de lesões mais recorrentes e agressivas. OBJETIVO: Correlacionar a expressão dos marcadores de apoptose (p53 e Bcl-2 e proliferação celular (Ki-67 e PCNA com os indicadores histológicos de gravidade do tumor. MÉTODOS: Estudaram-se cinco amostras das formas nodular, morfeiforme e superficial, respectivamente, e um grupo-controle com três pacientes livres de lesão. Empregou-se o teste de Mann-Whitney na comparação da expressão desses marcadores com a forma de apresentação do carcinoma basocelular. RESULTADOS: Verificou-se que a marcação do Bcl-2 foi expressiva nos CBCs ditos agressivos (variantes morfeiforme e nodular. Dos tumores estudados, 66,7% (n = 10 indicaram fortemente o p53. Nossos resultados mostram maior expressão do Ki-67 no carcinoma basocelular nodular e superficial, sem expressão nos controles. O PCNA mostrou forte marcação em todos os tipos de tumores e nos controles. CONCLUSÃO: Os achados nos permitem concluir que o Bcl-2 e o p53 apresentam tendência para diagnosticar gravidade do carcinoma basocelular e o Ki-67, por seu comportamento variável, não pode ser considerado como marcador de gravidade, assim como o PCNA, que não foi um bom marcador de proliferação celular.BACKGROUND: - Basal cell carcinoma is the most common form of human cancer. Studies employing molecular and genetic biology techniques, associated with histomorphology, lead to the identification of risk factors in the development of more recurring and aggressive lesions. OBJECTIVE - To correlate markers expression of apoptosis (p53 and bcl-2 and cell proliferation (Ki-67 and PCNA with histological indicators of tumor severity. METHODS - Five samples of the nodular, morpheaform and superficial types of carcinoma

  5. microRNA-328 inhibits cervical cancer cell proliferation and tumorigenesis by targeting TCF7L2

    International Nuclear Information System (INIS)

    Wang, Xuan; Xia, Ying

    2016-01-01

    microRNAs (miRNAs) play a vital role in tumor development and progression. In this study, we aimed to determine the expression and biological roles of miR-328 in cervical cancer and identify its direct target gene. Our data showed that miR-328 was significantly downregulated in human cervical cancer tissues and cells. Re-expression of miR-328 inhibited cervical cancer cell proliferation and colony formation in vitro and suppressed the growth of xenograft tumors in vivo. Bioinformatic analysis predicted TCF7L2 (an essential effector of canonical Wnt signaling) as a target gene of miR-328, which was confirmed by luciferase reporter assays. Enforced expression of miR-328 led to a decline in the expression of endogenous TCF7L2 in cervical cancer cells. In cervical cancer tissues, TCF7L2 protein levels were negatively correlated with miR-328 expression levels (r = −0.462, P = 0.017). Small interfering RNA-mediated knockdown of TCF7L2 significantly impaired the proliferation and colony formation of cervical cancer cells. Ectopic expression of a miRNA-resistant form of TCF7L2 significantly reversed the growth suppressive effects of miR-328 on cervical cancer cells, which was accompanied by induction of cyclin D1 expression. Taken together, our results provide first evidence for the growth suppressive activity of miR-328 in cervical cancer, which is largely ascribed to downregulation of TCF7L2. Restoration of miR-328 may have therapeutic potential in cervical cancer. -- Highlights: •miR-328 inhibits cervical cancer cell growth and tumorigenesis. •TCF7L2 is a direct target gene of miR-328 in cervical cancer. •Knockdown of TCF7L2 impairs the proliferation and colony formation of cervical cancer cells.

  6. microRNA-328 inhibits cervical cancer cell proliferation and tumorigenesis by targeting TCF7L2

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xuan [Department of Gynaecology, Qilu Hospital, Shandong University, Jinan (China); Department of Gynaecology, Yantai Yuhuangding Hospital, Qingdao University School of Medicine, Yantai (China); Xia, Ying, E-mail: YingXia2006@qq.com [Department of Gynecology, Huadong Hospital, Fudan University, Shanghai, 200040 (China)

    2016-06-24

    microRNAs (miRNAs) play a vital role in tumor development and progression. In this study, we aimed to determine the expression and biological roles of miR-328 in cervical cancer and identify its direct target gene. Our data showed that miR-328 was significantly downregulated in human cervical cancer tissues and cells. Re-expression of miR-328 inhibited cervical cancer cell proliferation and colony formation in vitro and suppressed the growth of xenograft tumors in vivo. Bioinformatic analysis predicted TCF7L2 (an essential effector of canonical Wnt signaling) as a target gene of miR-328, which was confirmed by luciferase reporter assays. Enforced expression of miR-328 led to a decline in the expression of endogenous TCF7L2 in cervical cancer cells. In cervical cancer tissues, TCF7L2 protein levels were negatively correlated with miR-328 expression levels (r = −0.462, P = 0.017). Small interfering RNA-mediated knockdown of TCF7L2 significantly impaired the proliferation and colony formation of cervical cancer cells. Ectopic expression of a miRNA-resistant form of TCF7L2 significantly reversed the growth suppressive effects of miR-328 on cervical cancer cells, which was accompanied by induction of cyclin D1 expression. Taken together, our results provide first evidence for the growth suppressive activity of miR-328 in cervical cancer, which is largely ascribed to downregulation of TCF7L2. Restoration of miR-328 may have therapeutic potential in cervical cancer. -- Highlights: •miR-328 inhibits cervical cancer cell growth and tumorigenesis. •TCF7L2 is a direct target gene of miR-328 in cervical cancer. •Knockdown of TCF7L2 impairs the proliferation and colony formation of cervical cancer cells.

  7. Vanadium-substituted heteropolyacids immobilized on amine- functionalized mesoporous MCM-41: A recyclable catalyst for selective oxidation of alcohols with H2O2

    International Nuclear Information System (INIS)

    Dong, Xinbo; Wang, Danjun; Li, Kebin; Zhen, Yanzhong; Hu, Huaiming; Xue, Ganglin

    2014-01-01

    Graphical abstract: Vanadium-substituted phosphotungstic acids are immobilized on amine- functionalized mesoporous MCM-41 and the hybrid catalyst is proved to be a highly efficient solid catalyst for the oxidation of aromatic alcohols to the corresponding carbonyl compounds with H 2 O 2 , featured by the high conversion and selectivity, easy recovery, and quite steady reuse. - Highlights: • Vanadium-substituted phosphotungstic acid immobilized on amine-functionalized mesoporous MCM-41 are prepared. • HPAs were fixed on the inner surface of mesoporous MCM-41 by chemical bonding to aminosilane groups. • The hybrid catalyst showed much higher catalytic activity than the pure HPAs. • The hybrid catalyst is a highly efficient recyclable solid catalyst for the selective oxidation of aromatic alcohols. - Abstract: New hybrid materials of vanadium-substituted phosphotungstic acids (VHPW) immobilized on amine-functionalized mesoporous MCM-41 (VHPW/MCM-41/NH 2 ) are prepared and characterized by FT-IR, XRD, N 2 adsorption, elemental analysis, SEM and TEM for their structural integrity and physicochemical properties. It is found that the structure of the heteropolyacids is retained upon immobilization over mesoporous materials. The catalytic activities of these hybrid materials are tested in the selective oxidation of alcohols to the carbonyl products with 30% aqueous H 2 O 2 as oxidant in toluene. The catalytic activities of different number of vanadium-substituted phosphotungstic acid are investigated, and among the catalysts, H 5 [PV 2 W 10 O 40 ] immobilized on amine-functionalized MCM-41 exhibits the highest activity with 97% conversion and 99% selectivity in the oxidation of benzyl alcohol to benzaldehyde. The hybrid catalyst is proved to be a highly efficient recyclable solid catalyst for the selective oxidation of aromatic alcohols to the corresponding aldehydes with H 2 O 2

  8. MCM3AP in recessive Charcot-Marie-Tooth neuropathy and mild intellectual disability

    NARCIS (Netherlands)

    Ylikallio, Emil; Woldegebriel, Rosa; Tumiati, Manuela; Isohanni, Pirjo; Ryan, Monique M.; Stark, Zornitza; Walsh, Maie; Sawyer, Sarah L.; Bell, Katrina M.; Oshlack, Alicia; Lockhart, Paul J.; Shcherbii, Mariia; Estrada-Cuzcano, Alejandro; Atkinson, Derek; Hartley, Taila; Tetreault, Martine; Cuppen, Inge; Van Der Pol, W. Ludo; Candayan, Ayse; Battaloglu, Esra; Parman, Yesim; Van Gassen, Koen L.I.; Van Den Boogaard, Marie José H.; Boycott, Kym M.; Kauppi, Liisa; Jordanova, Albena; Lönnqvist, Tuula; Tyynismaa, Henna

    2017-01-01

    Defects in mRNA export from the nucleus have been linked to various neurodegenerative disorders. We report mutations in the gene MCM3AP, encoding the germinal center associated nuclear protein (GANP), in nine affected individuals from five unrelated families. The variants were associated with severe

  9. CO2 methanation on the catalyst of Ni/MCM-41 promoted with CeO2.

    Science.gov (United States)

    Wang, Xiaoliu; Zhu, Lingjun; Liu, Yincong; Wang, Shurong

    2018-06-01

    CO 2 as a raw feed combined with renewable hydrogen for the production of useful chemicals and alternative energy products is one of the solutions to environmental and energy problems. In this study, a series of Ni-xCeO 2 /MCM-41 catalysts with a nickel content of 20wt% were prepared through deposition precipitation method for CO 2 methanation. Different characterization methods, including BET, XRD, TEM, SEM, H 2 -TPR and H 2 -TPD were applied to help explore the influence mechanism of CeO 2 on Ni/MCM-41 in CO 2 methanation. It was found that all CeO 2 -promoted catalysts exhibited enhanced catalytic activity when compared to Ni/MCM-41. The catalyst modified with 20wt% CeO 2 showed the best catalytic performance, with CO 2 conversion and CH 4 selectivity of 85.6% and 99.8%, respectively, at the temperature of 380°C under atmospheric pressure. The synergetic effects among Ni 0 active sites, the promoter and the support, including nickel dispersion improvement and increased CO 2 adsorption sites due to the addition of CeO 2 , were considered as important factors for high reactivity of the promoted catalysts. The stability test showed that the promoted catalyst maintained its high reactivity after 30h. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. [Effects of nicotine on bone marrow stromal cells proliferation and differentiation of chondrocyte in vitro].

    Science.gov (United States)

    Ying, Xiao-zhou; Peng, Lei; Cheng, Shao-wen; Chen, Qing-yu; Zhang, Wei; Kou, Dong-quan; Shen, Yue

    2011-11-01

    To examine the effects of various concentration of nicotine on bone marrow stromal cells (BMSCs) proliferation and differentiation of cartilaginous in vitro. BMSCs was obtained from femoral bone and tibia of New-Zealand albino rabbit. The cells of the 3rd generation were used in study. Different concentration of nicotine (0, 1 x 10(-7), 1 x 10(-6), 1 x 10(-5) M) were added into BMSCs. BMSCs proliferation was analyzed by MTT assay at the 1, 4, 7, 14 days. The expression of collagen type II and aggrecan as the marker genes of cartilaginous differentiation from BMSCs were detected by reverse transcriptase-polymerase chain reaction (RT-PCR). Microscope showed that BMSCs transformed from round to fusiform shape. The concentration of nicotine in 1 x 10(-7), 1 x 10(-6) M had a significant positive effect on cell proliferation and the expression of type II collagen in a time-dependent manner when supplemented in commonly used induction media (P<0.05). Concentrations of nicotine in 1 x 10(-7) can promote the expression of aggrecan at the 7th day after induction,and in 1 x 10(-5) M may inhibit the expression of type II collagen and aggrecan. It was implied that local application of nicotine at an appropriate concentration may be a promising approach for enhancing cartilaginous differentiation capacity of BMSCs in cartilage tissue engineering.

  11. Kinetic study of the catalytic pyrolysis of elephant grass using Ti-MCM-41

    Energy Technology Data Exchange (ETDEWEB)

    Fontes, Maria do Socorro Braga; Melo, Dulce Maria de Araujo; Rodrigues, Glicelia, E-mail: socorro.fontes@yahoo.com.br [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil); Barros, Joana Maria de Farias [Universidade Federal de Campina Grande (UFCG), Cuite, PB (Brazil). Dept. de Quimica; Braga, Renata Martins [Universidade Federal da Paraiba (UFPB/CEAR/DEER), Joao Pessoa, PB (Brazil). Centro de Energias Alternativas e Renovaveis. Dept. de Engenharia de Energia Renovaveis

    2014-08-15

    This work aimed to study the kinetics of thermal and catalytic pyrolysis using Ti-MCM-41 as catalyst in order to assess the catalytic pyrolysis efficiency compared to thermal pyrolysis of elephant grass. Ti-MCM-41 molecular sieve was synthesized by hydrothermal method from hydrogel with the following molar composition: 1.00 CTMABr: 4.00 SiO{sub 2}:X TiO{sub 2}: 1 + X Na{sub 2}O: 200.00 H{sub 2}O, which structure template used was cetyltrimethylammonium bromide (CTMABr). The materials synthesized were characterized by X-ray diffraction, IR spectroscopy, thermogravimetric analysis and specific area by the BET method, for subsequent application in the biomass pyrolysis process. The kinetic models proposed by Vyazovkin and Flynn-Wall were used to determine the apparent activation energy involved in the thermal and catalytic pyrolysis of elephant grass and the results showed that the catalyst used was effective in reducing the apparent activation energy involved in the thermal decomposition of elephant grass. (author)

  12. THE INFLUENCE OF Pd IMPREGNATION INTO Al-MCM-41 ON THE CHARACTERS AND ACTIVITY FOR BIOGASOLINE PRODUCTION BY CATALYTIC HYDROCRACKING OF FAMEs FROM NYAMPLUNG SEED OIL (Calophyllum Inophyllum

    Directory of Open Access Journals (Sweden)

    Hendro Juwono

    2013-08-01

    Full Text Available Biogasoline have been synthesized through catalytic hydrocracking reaction against FAMEs compounds (fatty acid methyl esters obtained from the transesterification of Nyamplung seed oil. The performance of Al-MCM-41 and Pd/Al-MCM-41 as the catalytic hydrocracking was compared. In this research, the influence of Pd impregnation into Al-MCM-41 catalyst on the characters and catalytic activity has been evaluated. The characters determined were crystallinity by using X-Ray Diffractometer (XRD, Si/Al ratio by Inductively Coupled Plasma (ICP, the acidity by pyridine adsorption, the surface area and pore volume by surface area analyzer and the morphology by Scanning Electron Microscopy (SEM. Catalytic activity was examined for hydrocracking of free fatty acid methyl esters (FAMEs produced from the transesterification of Nyamplung seed oil, by Hydrogen flowing. The research result showed that impregnation of Pd into Al-MCM-41 has been successfully carried out, which did not destroy the structural morphology of the catalyst. It was also discovered that the Pd impregnation could increase Si/Al ratio and the acidity but it leads to decrease in the catalyst surface area and the volume. Furthermore, Pd impregnated Al-MCM-41 showed superior activity compared to Al-MCM-41 for FAMEs hydrocracking. The superiority was indicated by higher effectiveness and yields selectiveness, that were 100% hydrocarbon composed of C9-C18 that was dominated by C12 emerging the gasoline fraction, compared of that by the results used Al-MCM-41 catalyst that were 97% hydrocarbon consisted of C8-C20 with equal abundance.

  13. Quick photo-Fenton degradation of phenolic compounds by Cu/Al2O3-MCM-41 under visible light irradiation: small particle size, stabilization of copper, easy reducibility of Cu and visible light active material.

    Science.gov (United States)

    Pradhan, Amaresh C; Nanda, Binita; Parida, K M; Das, Mira

    2013-01-14

    The present study reports the photo-Fenton degradation of phenolic compounds (phenol, 2-chloro-4-nitrophenol and 4-chloro-2-nitrophenol) in aqueous solution using mesoporous Cu/Al(2)O(3)-MCM-41 nanocomposite as a heterogeneous photo-Fenton-like catalyst. The in situ incorporation of mesoporous Al(2)O(3) (MA) into the framework of MCM-41 (sol-gel method) forms Al(2)O(3)-MCM-41 and wetness impregnation of Cu(II) on Al(2)O(3)-MCM-41 generates mesoporous Cu/Al(2)O(3)-MCM-41 composite. The effects of pH and H(2)O(2) concentration on degradation of phenol, 2-chloro-4-nitrophenol and 4-chloro-2-nitrophenol are studied. Kinetics analysis shows that the photocatalytic degradation reaction follows a first-order rate equation. Mesoporous 5 Cu/Al(2)O(3)-MCM-41 is found to be an efficient photo-Fenton-like catalyst for the degradation of phenolic compounds. It shows nearly 100% degradation in 45 min at pH 4. The combined effect of small particle size, stabilization of Cu(2+) on the support Al(2)O(3)-MCM-41, ease reducibility of Cu(2+) and visible light activeness are the key factors for quick degradation of phenolic compounds by Cu/Al(2)O(3)-MCM-41.

  14. The Cdc45/RecJ-like protein forms a complex with GINS and MCM, and is important for DNA replication in Thermococcus kodakarensis.

    Science.gov (United States)

    Nagata, Mariko; Ishino, Sonoko; Yamagami, Takeshi; Ogino, Hiromi; Simons, Jan-Robert; Kanai, Tamotsu; Atomi, Haruyuki; Ishino, Yoshizumi

    2017-10-13

    The archaeal minichromosome maintenance (MCM) has DNA helicase activity, which is stimulated by GINS in several archaea. In the eukaryotic replicative helicase complex, Cdc45 forms a complex with MCM and GINS, named as CMG (Cdc45-MCM-GINS). Cdc45 shares sequence similarity with bacterial RecJ. A Cdc45/RecJ-like protein from Thermococcus kodakarensis shows a bacterial RecJ-like exonuclease activity, which is stimulated by GINS in vitro. Therefore, this archaeal Cdc45/RecJ is designated as GAN, from GINS-associated nuclease. In this study, we identified the CMG-like complex in T. kodakarensis cells. The GAN·GINS complex stimulated the MCM helicase, but MCM did not affect the nuclease activity of GAN in vitro. The gene disruption analysis showed that GAN was non-essential for its viability but the Δgan mutant did not grow at 93°C. Furthermore, the Δgan mutant showed a clear retardation in growth as compared with the parent cells under optimal conditions at 85°C. These deficiencies were recovered by introducing the gan gene encoding the nuclease deficient GAN protein back to the genome. These results suggest that the replicative helicase complex without GAN may become unstable and ineffective in replication fork progression. The nuclease activity of GAN is not related to the growth defects of the Δgan mutant cells. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  15. A Framework for Evaluating Advanced Search Concepts for Multiple Autonomous Underwater Vehicle (AUV) Mine Countermeasures (MCM)

    National Research Council Canada - National Science Library

    Gooding, Trent

    2001-01-01

    .... In recent years, autonomous underwater vehicles (AUV) have emerged as a viable technology for conducting underwater search, survey, and clearance operations in support of the mine countermeasures (MCM) mission...

  16. A Comparative Characterization of the HPA-MCM-48 Type Catalysts Produced by the Direct Hydrothermal and Room Temperature Synthesis Methods

    International Nuclear Information System (INIS)

    Gucbilmez, Y.; Calis, I.; Yargic, A. S.

    2012-01-01

    MCM-48 type support materials synthesized by the direct hydrothermal synthesis (HTS) and room temperature synthesis (RTS) methods were incorporated with tungstophosphoric acid (TPA) in the range of 10-40 wt% by using a wet impregnation technique in methanol solutions. Resulting HPA-MCM-48 catalysts were characterized by the XRD, Nitrogen Physisorption, SEM, TEM, EDS, and FT-IR methods in order to determine the effects of different initial synthesis conditions on the catalyst properties. RTS samples were found to have better crystalline structures, higher BET surface areas, and higher BJH pore volumes than HTS samples. They also had slightly higher TPA incorporation, except for the 40 wt% samples, as evidenced by the EDS results. Keggin ion structure was preserved, for both methods, even at the highest acid loading of 40 wt%. It was concluded that the simpler and more economical RTS method was more successful than the HTS method for hetero poly acid incorporation into MCM-48 type materials

  17. Cell cycle dependent RRM2 may serve as proliferation marker and pharmaceutical target in adrenocortical cancer.

    Science.gov (United States)

    Grolmusz, Vince Kornél; Karászi, Katalin; Micsik, Tamás; Tóth, Eszter Angéla; Mészáros, Katalin; Karvaly, Gellért; Barna, Gábor; Szabó, Péter Márton; Baghy, Kornélia; Matkó, János; Kovalszky, Ilona; Tóth, Miklós; Rácz, Károly; Igaz, Péter; Patócs, Attila

    2016-01-01

    Adrenocortical cancer (ACC) is a rare, but agressive malignancy with poor prognosis. Histopathological diagnosis is challenging and pharmacological options for treatment are limited. By the comparative reanalysis of the transcriptional malignancy signature with the cell cycle dependent transcriptional program of ACC, we aimed to identify novel biomarkers which may be used in the histopathological diagnosis and for the prediction of therapeutical response of ACC. Comparative reanalysis of publicly available microarray datasets included three earlier studies comparing transcriptional differences between ACC and benign adrenocortical adenoma (ACA) and one study presenting the cell cycle dependent gene expressional program of human ACC cell line NCI-H295R. Immunohistochemical analysis was performed on ACC samples. In vitro effects of antineoplastic drugs including gemcitabine, mitotane and 9-cis-retinoic acid alone and in combination were tested in the NCI-H295R adrenocortical cell line. Upon the comparative reanalysis, ribonucleotide reductase subunit 2 (RRM2), responsible for the ribonucleotide dezoxyribonucleotide conversion during the S phase of the cell cycle has been validated as cell cycle dependently expressed. Moreover, its expression was associated with the malignancy signature, as well. Immunohistochemical analysis of RRM2 revealed a strong correlation with Ki67 index in ACC. Among the antiproliferative effects of the investigated compounds, gemcitabine showed a strong inhibition of proliferation and an increase of apoptotic events. Additionally, RRM2 has been upregulated upon gemcitabine treatment. Upon our results, RRM2 might be used as a proliferation marker in ACC. RRM2 upregulation upon gemcitabine treatment might contribute to an emerging chemoresistance against gemcitabine, which is in line with its limited therapeutical efficacy in ACC, and which should be overcome for successful clinical applications.

  18. [Prognostic and predictive molecular markers for urologic cancers].

    Science.gov (United States)

    Hartmann, A; Schlomm, T; Bertz, S; Heinzelmann, J; Hölters, S; Simon, R; Stoehr, R; Junker, K

    2014-04-01

    Molecular prognostic factors and genetic alterations as predictive markers for cancer-specific targeted therapies are used today in the clinic for many malignancies. In recent years, many molecular markers for urogenital cancers have also been identified. However, these markers are not clinically used yet. In prostate cancer, novel next-generation sequencing methods revealed a detailed picture of the molecular changes. There is growing evidence that a combination of classical histopathological and validated molecular markers could lead to a more precise estimation of prognosis, thus, resulting in an increasing number of patients with active surveillance as a possible treatment option. In patients with urothelial carcinoma, histopathological factors but also the proliferation of the tumor, mutations in oncogenes leading to an increasing proliferation rate and changes in genes responsible for invasion and metastasis are important. In addition, gene expression profiles which could distinguish aggressive tumors with high risk of metastasis from nonmetastasizing tumors have been recently identified. In the future, this could potentially allow better selection of patients needing systemic perioperative treatment. In renal cell carcinoma, many molecular markers that are associated with metastasis and survival have been identified. Some of these markers were also validated as independent prognostic markers. Selection of patients with primarily organ-confined tumors and increased risk of metastasis for adjuvant systemic therapy could be clinically relevant in the future.

  19. Gut microbial colonization orchestrates TLR2 expression, signaling and epithelial proliferation in the small intestinal mucosa.

    Directory of Open Access Journals (Sweden)

    Nives Hörmann

    Full Text Available The gut microbiota is an environmental factor that determines renewal of the intestinal epithelium and remodeling of the intestinal mucosa. At present, it is not resolved if components of the gut microbiota can augment innate immune sensing in the intestinal epithelium via the up-regulation of Toll-like receptors (TLRs. Here, we report that colonization of germ-free (GF Swiss Webster mice with a complex gut microbiota augments expression of TLR2. The microbiota-dependent up-regulation of components of the TLR2 signaling complex could be reversed by a 7 day broad-spectrum antibiotic treatment. TLR2 downstream signaling via the mitogen-activated protein kinase (ERK1/2 and protein-kinase B (AKT induced by bacterial TLR2 agonists resulted in increased proliferation of the small intestinal epithelial cell line MODE-K. Mice that were colonized from birth with a normal gut microbiota (conventionally-raised; CONV-R showed signs of increased small intestinal renewal and apoptosis compared with GF controls as indicated by elevated mRNA levels of the proliferation markers Ki67 and Cyclin D1, elevated transcripts of the apoptosis marker Caspase-3 and increased numbers of TUNEL-positive cells per intestinal villus structure. In accordance, TLR2-deficient mice showed reduced proliferation and reduced apoptosis. Our findings suggest that a tuned proliferation response of epithelial cells following microbial colonization could aid to protect the host from its microbial colonizers and increase intestinal surface area.

  20. Delta(9)-tetrahydrocannabinol inhibits 17beta-estradiol-induced proliferation and fails to activate androgen and estrogen receptors in MCF7 human breast cancer cells.

    Science.gov (United States)

    von Bueren, A O; Schlumpf, M; Lichtensteiger, W

    2008-01-01

    Delta(9)-tetrahydrocannabinol (THC) exerts palliative effects in cancer patients, but produces adverse effects on the endocrine and reproductive systems. Experimental evidence concerning such effects is controversial. Whether THC exhibits estrogenic or androgenic activity in vitro was investigated. Estrogenic effects of THC were analyzed in vitro by measuring the proliferation of estrogen-sensitive MCF7 cells. Androgenic activity was investigated by the A-Screen assay that measures androgen-dependent inhibition of proliferation of the androgen receptor (AR)-positive human mammary carcinoma cell line, MCF7-AR1. In contrast to 17beta-estradiol, included as positive control with an EC50 value (concentration required for 50% of maximal 17beta-estradiol-induced proliferation) of 1.00 x 10(-12) M, THC failed to induce cell proliferation in the MCF7 cell line at concentrations between 10(-13) and 10(-4) M. THC inhibited 17beta-estradiol-induced proliferation in wild-type MCF7 and MCF7-AR1 cells, with an IC50 value of 2.6 x 10(-5) M and 9 x 10(-6) M, respectively. THC failed to act as an estrogen, but antagonized 17beta-estradiol-induced proliferation. This effect was independent of the AR expression level.

  1. Síntesis de nopol a partir de β-pineno y aceite de trementina con el catalizador Sn-MCM-41

    Directory of Open Access Journals (Sweden)

    Edwin Alarcón Durango

    2006-01-01

    Full Text Available Se obtuvo nopol mediante la reacción de Prins por condensación de β-pineno y paraformaldehído usando el catalizador Sn-MCM-41. El catalizador se sintetizó por deposición química al vapor de una sal precursora de Sn sobre MCM-41. Las reacciones se realizaron partiendo de β-pineno de alta pureza o aceite comercial de trementina. Se evaluó el efecto de varios parámetros en la selectividad a nopol, tales como: la carga de Sn en el catalizador, la cantidad de solvente y catalizador, la temperatura y el tiempo de reacción. Los catalizadores se caracterizaron por DRX, IR, UV-VIS, absorción atómica y área superficial BET. Usando Sn-MCM-41 con bajas cargas de Sn se alcanzaron rendimientos a nopol cercanos a 100% con β-pineno de alta pureza. Partiendo de trementina como fuente de β-pineno y relaciones equimolares de reactivos, se alcanzaron selectividades a nopol hasta del 93%.

  2. Los arquetipos de los MCM: héroes y antíhéroes de los niños

    Directory of Open Access Journals (Sweden)

    OLIVIA VELARDE

    1992-01-01

    Full Text Available La presente investigación se ha llevado a cabo desde un enfoque que toma en cuenta la interdependencia entre los factores sociales, comunicativos y cognitivos en los procesos de enculturización infantil. La autora analiza las correspondencias existentes entre el uso de los MCM y las representaciones que los niños construyen sobre sí mismos y sobre el mundo que les rodea. Sobre la base de elementos de naturaleza tan heterogénea como los héroes de los relatos en los MCM, se muestra que el laborioso trabajo cognitivo realizado por los niños cuando definen la identidad y el comportamiento de los héroes sirve, sobre todo, para la autoafirmación del rol sexual; y que el trabajo no menos laborioso que llevan a cabo cuando definen qué puede ser imitado y no imitado de los personajes de los MCM y cuál es la importancia social de éstos sirve, sobre todo, para definir el rol de clase.

  3. On the hydrothermal stability of MCM-41. Evidence of capillary tension-induced effects

    NARCIS (Netherlands)

    Perez, Lidia Lopez; van Eck, Ernst R. H.; Melian-Cabrera, Ignacio

    2016-01-01

    MCM-41's limited hydrothermal stability has been often related to the hydrolysis of Si-O-Si bonds due to the low degree of condensation, its thin walls or a combination of them. In this work, evidence for an additional factor is provided; a physical effect that occurs during the drying of the

  4. Synthesis of magnetic core-shell structure Fe3O4@MCM-41 nanoparticle by vesicles in aqueous solutions☆

    Institute of Scientific and Technical Information of China (English)

    Weiming Song; Xuesong Liu; Ying Yang; Xuejia Han; Qigang Deng

    2015-01-01

    In this study, magnetic core–shel structure Fe3O4@MCM-41 nanoparticles were synthesized with vesicles as soft templates. In the preparation, FeCl2 and tetraethy orthosilicate (TEOS) were selected as Fe processor and Si pre-cursor, respectively. Stable vesicles first formed in 0.03 mol·L−1 1:2 mixture of anionic surfactant sodium dode-cyl sulfate and cationic surfactant cetyltrimethyl ammonium bromide. Then, TEOS was added in the vesicle aqueous solution, leading to a highly dispersed solution. After high-temperature calcination, Fe3O4@MCM-41 nanoparticles were obtained. Their structure and morphology were characterized by Saturn Digisizer, transmis-sion electron microscope and vibrating sample magneto-meter. The results indicate that the vesicles are spherical and their size could be tuned between 20 and 50 nm. The average grain diameter of synthesize magnetic core–shel Fe3O4@MCM-41 particles is 100–150 nm and most of them are in el iptical shape. The dispersion of magnet-ic particles is very good and magnetization values are up to 33.44 emu·g−1, which are superior to that of other Fe3O4 materials reported.

  5. Room temperature synthesis of Si-MCM-41 using polymeric version of ethyl silicate as a source of silica

    International Nuclear Information System (INIS)

    Gaydhankar, T.R.; Samuel, V.; Jha, R.K.; Kumar, R.; Joshi, P.N.

    2007-01-01

    Synthesis of mesoporous MCM-41 materials at room temperature using less expensive polymeric version of ethyl silicate (40 wt% SiO 2 ) as a source of silica was established. The influence of crucial synthesis parameters such as molar ratios of H 2 O/NH 4 OH, NH 4 OH/SiO 2 and CTMABr/SiO 2 in gel on the quality of the phase formed was investigated. Powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and low temperature N 2 adsorption-desorption isotherms have been employed to characterize the products. The magnitude of orderness, textural properties and thermal stability of the Si-MCM-41 samples prepared under identical judiciously pre-controlled synthesis conditions using ethyl silicate and conventional tetraethyl orthosilicate (TEOS) were assessed. Even though, ethyl silicate has proved to be suitable source for the preparation of MCM-41 at room temperature, there exists an optimum value of H 2 O/NH 4 OH for different NH 4 OH/SiO 2 molar ratios in the gel. Changes in the morphology were observed when NH 4 OH/SiO 2 , H 2 O/NH 4 OH molar ratios in the gels were changed

  6. Use of TiO{sub 2}/Cr-MCM-41 molecular sieve irradiated with visible light for the degradation of thiophene in the gas phase

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Fabielle C.; Canela, Maria Cristina; Stumbo, Alexandre M. [Laboratorio de Ciencias Quimicas (LCQUI), Universidade Estadual do Norte Fluminense Darcy Ribeiro, Av. Alberto Lamego, 2000 Campos dos Goytacazes-RJ, CEP 28013-602 (Brazil)

    2008-04-15

    Photocatalytic processes using TiO{sub 2} and UV radiation to eliminate pollutants are not yet suitable for industrial facilities due to their high consumption of energy. Transition metals incorporated onto mesoporous MCM-41 molecular sieves impregnated with TiO{sub 2} constitute an alternative that allows the use of solar light. In this study, Cr-substituted MCM-41 were synthesized (Si/Cr = 100, 50 and {infinity}) and impregnated with TiO{sub 2} (10 and 20 wt.%). Raman results showed the formation of anatase. Electronic spectroscopy and EPR exposed the formation of trivalent chromium after impregnation with TiO{sub 2}, which is related to a Cr-TiO{sub 2} interaction. The synthesized photocatalysts, as well as TiO{sub 2} P25, were tested in the degradation of thiophene in gaseous phase. A test with UV lamp showed 100% of conversion for 20%TiO{sub 2}/Cr-MCM-41(100) and exceeded the activity of TiO{sub 2} P25, probably due to the higher dispersion of TiO{sub 2} on the surface of the molecular sieve. During tests using visible light and 20%TiO{sub 2}/Cr-MCM-41(50) higher conversions than those of 20%TiO{sub 2}/Cr-MCM-41(100) and TiO{sub 2} P25 were observed. These results indicate that chromium concentration is a key factor influencing the photocatalytic activity under visible light. (author)

  7. Dual effects of adenovirus-mediated thrombopoietin gene transfer on hepatic oval cell proliferation and platelet counts

    International Nuclear Information System (INIS)

    Ichiba, Miho; Shimomura, Takashi; Murai, Rie; Hashiguchi, Koichi; Saeki, Toshiya; Yoshida, Yoko; Kanbe, Takamasa; Tanabe, Naotada; Tsuchiya, Hiroyuki; Miura, Norimasa; Tajima, Fumihito; Kurimasa, Akihiro; Hamada, Hirofumi; Shiota, Goshi

    2005-01-01

    Thrombopoietin (TPO) is the growth factor for megakaryocytes and platelets, however, it also acts as a potent regulator of stem cell proliferation. To examine the significance of TPO expression in proliferation of hepatic oval cells, the effect of adenovirus-mediated TPO gene transfer into livers of the Solt-Farber model, which mimics the condition where liver regeneration is impaired, was examined. Hepatic TPO mRNA peaked its expression at 2 days after gene transduction and then gradually decreased. The peripheral platelet number began to increase at 4 days (P < 0.05) and reached its plateau at 9 days (P < 0.01). Oval cells expressed c-Mpl, a receptor for TPO as well as immature hematopoietic and hepatocytic surface markers such as CD34 and AFP. The proliferating cell nuclear antigen-positive oval cells in rats into which adenovirus-TPO gene was transferred at 7 and 9 days were significantly greater than those in adenovirus-LacZ gene transferred (P < 0.05, each), and the total numbers of oval cells in the adenovirus-TPO gene transferred at 9 and 13 days were also significantly greater than those in adenovirus-LacZ gene transferred (P < 0.05, each). Expression of SCF protein was increased at 4, 7, and 9 days by TPO gene administration and that of c-Kit was increased at 4 and 7 days. These data suggest that adenovirus-mediated TPO gene transfer stimulated oval cell proliferation in liver as well as increasing peripheral platelet counts, emphasizing the significance of the TPO/c-Mpl system in proliferation of hepatic oval cells

  8. RUNX1 suppression induces megakaryocytic differentiation of UT-7/GM cells

    International Nuclear Information System (INIS)

    Nagai, Ryohei; Matsuura, Eri; Hoshika, Yusuke; Nakata, Emi; Nagura, Hironori; Watanabe, Ayako; Komatsu, Norio; Okada, Yoshiaki; Doi, Takefumi

    2006-01-01

    The transcription factor RUNX1 plays a crucial role in hematopoiesis. RUNX1 regulates both differentiation and proliferation of hematopoietic cells. Several reports have shown that RUNX1 participates in megakaryopoiesis, which is a process that leads to formation of platelets. However, to date, the mechanisms by which this occurs have not been fully elucidated. In the present study, we investigated whether siRNA-mediated depletion of RUNX1 affected megakaryopoiesis of UT-7/GM cells. The depletion of RUNX1 in UT-7/GM cells resulted in up-regulation of the expression of megakaryocytic markers and polyploidization, while cell proliferation was down-regulated. Furthermore, the overexpression of RUNX1 decreased the activity of megakaryocytic gene promoters. These results suggest that RUNX1 down-regulates terminal differentiation of megakaryocytes and promotes proliferation of megakaryocytic progenitors

  9. Peripheral T-lymphocytes express WNT7A and its restoration in leukemia-derived lymphoblasts inhibits cell proliferation

    International Nuclear Information System (INIS)

    Ochoa-Hernández, Alejandra B; Bravo-Cuellar, Alejandro; Jave-Suarez, Luis F; Barros-Núñez, Patricio; Aguilar-Lemarroy, Adriana; Ramos-Solano, Moisés; Meza-Canales, Ivan D; García-Castro, Beatriz; Rosales-Reynoso, Mónica A; Rosales-Aviña, Judith A; Barrera-Chairez, Esperanza; Ortíz-Lazareno, Pablo C; Hernández-Flores, Georgina

    2012-01-01

    WNT7a, a member of the Wnt ligand family implicated in several developmental processes, has also been reported to be dysregulated in some types of tumors; however, its function and implication in oncogenesis is poorly understood. Moreover, the expression of this gene and the role that it plays in the biology of blood cells remains unclear. In addition to determining the expression of the WNT7A gene in blood cells, in leukemia-derived cell lines, and in samples of patients with leukemia, the aim of this study was to seek the effect of this gene in proliferation. We analyzed peripheral blood mononuclear cells, sorted CD3 and CD19 cells, four leukemia-derived cell lines, and blood samples from 14 patients with Acute lymphoblastic leukemia (ALL), and 19 clinically healthy subjects. Reverse transcription followed by quantitative Real-time Polymerase chain reaction (qRT-PCR) analysis were performed to determine relative WNT7A expression. Restoration of WNT7a was done employing a lentiviral system and by using a recombinant human protein. Cell proliferation was measured by addition of WST-1 to cell cultures. WNT7a is mainly produced by CD3 T-lymphocytes, its expression decreases upon activation, and it is severely reduced in leukemia-derived cell lines, as well as in the blood samples of patients with ALL when compared with healthy controls (p ≤0.001). By restoring WNT7A expression in leukemia-derived cells, we were able to demonstrate that WNT7a inhibits cell growth. A similar effect was observed when a recombinant human WNT7a protein was used. Interestingly, restoration of WNT7A expression in Jurkat cells did not activate the canonical Wnt/β-catenin pathway. To our knowledge, this is the first report evidencing quantitatively decreased WNT7A levels in leukemia-derived cells and that WNT7A restoration in T-lymphocytes inhibits cell proliferation. In addition, our results also support the possible function of WNT7A as a tumor suppressor gene as well as a therapeutic

  10. Value of preoperative enhanced multi-slice spiral CT scan for judging TNM staging of gastric cancer as well as its relationship with tumor marker and proliferation molecule expression

    Directory of Open Access Journals (Sweden)

    Ai-Jun Wu

    2016-12-01

    Full Text Available Objective: To study the value of preoperative enhanced multi-slice spiral CT scan for judging TNM staging of gastric cancer as well as its relationship with tumor marker and proliferation molecule expression. Methods: A total of 135 patients with gastric cancer who received surgical resection in our hospital between May 2012 and October 2015 were selected as the research subjects, preoperative enhanced multi-slice spiral CT scan was conducted to judge TNM staging, and serum was collected to determine the content of tumor markers; tumor tissue was collected after operation to determine the content of cytokines and pro-proliferation molecules. Results: CEA, CA199, CA153, CA125 and CA724 content in serum as well as TGFβ1, TGFβ2, VEGF, FGF2, PTP1B, PIK3CD, Survivin, Ezrin and YAP content in gastric cancer tissue of patients with TNM II, III and IV stage gastric cancer were significantly higher than those of patients with TNM I stage; CEA, CA199, CA153, CA125 and CA724 content in serum as well as TGFβ1, TGFβ2, VEGF, FGF2, PTP1B, PIK3CD, Survivin, Ezrin and YAP content in gastric cancer tissue of patients with TNM III and IV stage gastric cancer were significantly higher than those of patients with TNM II stage; CEA, CA199, CA153, CA125 and CA724 content in serum as well as TGFβ1, TGFβ2, VEGF, FGF2, PTP1B, PIK3CD, Survivin, Ezrin and YAP content in gastric cancer tissue of patients with TNM IV stage gastric cancer were significantly higher than those of patients with TNM III stage. Conclusions: TNM staging of gastric cancer decided by preoperative enhanced multi-slice spiral CT scan has good consistency with the content of tumor markers in serum and proliferation molecules in tumor lesion.

  11. Evaluation of estrogenic potential of flavonoids using a recombinant yeast strain and MCF7/BUS cell proliferation assay.

    Directory of Open Access Journals (Sweden)

    Flávia A Resende

    Full Text Available Phytoestrogens are of interest because of their reported beneficial effects on many human maladies including cancer, neurodegeneration, cardiovascular disease and diabetes. Furthermore, there is a search for compounds with estrogenic activity that can replace estrogen in hormone replacement therapy during menopause, without the undesirable effects of estrogen, such as the elevation of breast cancer occurrence. Thus, the principal objective of this study was to assess the estrogenic activity of flavonoids with different hydroxylation patterns: quercetin, kaempferol, luteolin, fisetin, chrysin, galangin, flavone, 3-hydroxyflavone, 5-hydroxyflavone and 7-hydroxyflavone via two different in vitro assays, the recombinant yeast assay (RYA and the MCF-7 proliferation assay (E-screen, since the most potent phytoestrogens are members of the flavonoid family. In these assays, kaempferol was the only compound that showed ERα-dependent transcriptional activation activity by RYA, showing 6.74±1.7 nM EEQ, besides acting as a full agonist for the stimulation of proliferation of MCF-7/BUS cells. The other compounds did not show detectable levels of interaction with ER under the conditions used in the RYA. However, in the E-screen assay, compounds such as galangin, luteolin and fisetin also stimulated the proliferation of MCF-7/BUS cells, acting as partial agonists. In the evaluation of antiestrogenicity, the compounds quercetin, chrysin and 3-hydroxyflavone significantly inhibited the cell proliferation induced by 17-β-estradiol in the E-screen assay, indicating that these compounds may act as estrogen receptor antagonists. Overall, it became clear in the assay results that the estrogenic activity of flavonoids was affected by small structural differences such as the number of hydroxyl groups, especially those on the B ring of the flavonoid.

  12. Vanadium-substituted heteropolyacids immobilized on amine- functionalized mesoporous MCM-41: A recyclable catalyst for selective oxidation of alcohols with H{sub 2}O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Xinbo [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, Department of Chemistry (Ministry of Education), Northwest University, Xi' an 710069 (China); Wang, Danjun [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, Department of Chemistry (Ministry of Education), Northwest University, Xi' an 710069 (China); College of Chemistry Chemical Engineering, Yanan University, Shaanxi Key Laboratory of Chemical Reaction Engineering, Yan' an 716000 (China); Li, Kebin [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, Department of Chemistry (Ministry of Education), Northwest University, Xi' an 710069 (China); Zhen, Yanzhong [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, Department of Chemistry (Ministry of Education), Northwest University, Xi' an 710069 (China); College of Chemistry Chemical Engineering, Yanan University, Shaanxi Key Laboratory of Chemical Reaction Engineering, Yan' an 716000 (China); Hu, Huaiming [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, Department of Chemistry (Ministry of Education), Northwest University, Xi' an 710069 (China); Xue, Ganglin, E-mail: xglin707@163.com [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, Department of Chemistry (Ministry of Education), Northwest University, Xi' an 710069 (China)

    2014-09-15

    Graphical abstract: Vanadium-substituted phosphotungstic acids are immobilized on amine- functionalized mesoporous MCM-41 and the hybrid catalyst is proved to be a highly efficient solid catalyst for the oxidation of aromatic alcohols to the corresponding carbonyl compounds with H{sub 2}O{sub 2}, featured by the high conversion and selectivity, easy recovery, and quite steady reuse. - Highlights: • Vanadium-substituted phosphotungstic acid immobilized on amine-functionalized mesoporous MCM-41 are prepared. • HPAs were fixed on the inner surface of mesoporous MCM-41 by chemical bonding to aminosilane groups. • The hybrid catalyst showed much higher catalytic activity than the pure HPAs. • The hybrid catalyst is a highly efficient recyclable solid catalyst for the selective oxidation of aromatic alcohols. - Abstract: New hybrid materials of vanadium-substituted phosphotungstic acids (VHPW) immobilized on amine-functionalized mesoporous MCM-41 (VHPW/MCM-41/NH{sub 2}) are prepared and characterized by FT-IR, XRD, N{sub 2} adsorption, elemental analysis, SEM and TEM for their structural integrity and physicochemical properties. It is found that the structure of the heteropolyacids is retained upon immobilization over mesoporous materials. The catalytic activities of these hybrid materials are tested in the selective oxidation of alcohols to the carbonyl products with 30% aqueous H{sub 2}O{sub 2} as oxidant in toluene. The catalytic activities of different number of vanadium-substituted phosphotungstic acid are investigated, and among the catalysts, H{sub 5}[PV{sub 2}W{sub 10}O{sub 40}] immobilized on amine-functionalized MCM-41 exhibits the highest activity with 97% conversion and 99% selectivity in the oxidation of benzyl alcohol to benzaldehyde. The hybrid catalyst is proved to be a highly efficient recyclable solid catalyst for the selective oxidation of aromatic alcohols to the corresponding aldehydes with H{sub 2}O{sub 2}.

  13. Preparation of Organic-Inorganic Hybrid Materials Based on MCM-41 and Its Applications

    Directory of Open Access Journals (Sweden)

    Sana M. Alahmadi

    2013-01-01

    Full Text Available This work reports the covalent attachment of three different calix[4]arenes (calix[4]arene (C4, p-sulfonatocalix[4]arene (C4S, and p-tert-butyl-calix[4]arene (PC4 to MCM-41, using a three-step modification process. 3-Chloropropyltrimethoxysilane (ClPTS was first attached to the mesoporous silica surface and subsequently converted to amides via the reaction with toluene diisocyanate (TDI. Finally, calix[4]arene derivatives attached to the isocyanate ending remained available on toluene di-iso-cyanate. Changes in the surface properties of the mesoporous silica caused by the chemical modification were monitored using the Fourier transform infrared spectroscopy (FTIR, thermal analysis (TGA, and elemental analysis. The FTIR spectra and TGA analysis verify that the calix[4]arene derivatives are covalently attached to the mesoporous silica. The preservation of the MCM-41 channel system was checked by the X-ray diffraction and nitrogen adsorption analysis. These materials were then used to evaluate the sorption properties of some organotins compounds (Tributyltin (TBT, Triphenyltin (TPT, and Dibutyltin (DBT.

  14. Imaging regional variation of cellular proliferation in gliomas using 3'-deoxy-3'-[18F]fluorothymidine positron-emission tomography: an image-guided biopsy study

    International Nuclear Information System (INIS)

    Price, S.J.; Fryer, T.D.; Cleij, M.C.; Dean, A.F.; Joseph, J.; Salvador, R.; Wang, D.D.; Hutchinson, P.J.; Clark, J.C.; Burnet, N.G.; Pickard, J.D.; Aigbirhio, F.I.

    2009-01-01

    Aim: To compare regional variations in uptake of 3'-deoxy-3'- [ 18 F]-fluorothymidine (FLT) images using positron-emission tomography (PET) with measures of cellular proliferation from biopsy specimens obtained by image-guided brain biopsies. Materials and methods: Fourteen patients with a supratentorial glioma that required an image-guided brain biopsy were imaged preoperatively with dynamic PET after the administration of FLT. Maps of FLT irreversible uptake rate (K i ) and standardized uptake value (SUV) were calculated. These maps were co-registered to a gadolinium-enhanced T1-weighted spoiled gradient echo (SPGR) sequence that was used for biopsy guidance, and the mean and maximum K i and SUV determined for each biopsy site. These values were correlated with the MIB-1 labelling index (a tissue marker of proliferation) from these biopsy sites. Results: A total of 57 biopsy sites were studied. Although all measures correlated with MIB-1 labelling index, K i max provided the best correlation (Pearson coefficient, r = 0.68; p i mean (±SD) was significantly higher than in normal tissue (3.3 ± 1.7 x 10 -3 ml plasma /min/ml tissue versus 1.2 ± 0.7 x 10 -3 ml plasma /min/ml tissue ; p = 0.001). High-grade gliomas showed heterogeneous uptake with a mean K i of 7.7 ± 4 x 10 -3 ml plasma /min/ml tissue . A threshold K i mean of 1.8 x 10 -3 differentiates between normal tissue and tumour (sensitivity 84%, specificity 88%); however, the latter threshold underestimated the extent of tumour in half the cases. SUV closely agreed with K i measurements. Conclusion: FLT PET is a useful marker of cellular proliferation that correlates with regional variation in cellular proliferation; however, it is unable to identify the margin of gliomas

  15. Synthesis of AL-MCM-41 using gravel drilling the source of silica from wells drilling; Sintese do AL-MCM-41 usando como fonte de silica o cascalho de perfuracao de pocos de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Fontes, M.S.B.; Costa, C.C.; Melo, D.M.A.; Viana, L.M.; Viana, S.O.; Santos, L.M., E-mail: socorro.fontes@Yahoo.com.br [Universidade Federal do Rio grande do Norte (UFRN), Natal, RN (Brazil)

    2016-07-01

    The aim of this study was to synthesize Al-MCM-41 using gravel drilling as alternative source of silica, aiming at sustainable production and low cost. For hydrothermal synthesis of Al-MCM-41 was used gravel and sodium silicate as source of silica and sodium, respectively. The structural driver used was cetyltrimethylammonium bromide (CTMABr) and solvent distilled water. The hydrothermal synthesis was conducted at 100 ° C in a Teflon autoclave 45 ml jacketed stainless steel for a period of 120 hours with daily correcting pH (range 9-10) using 30% acetic acid. The material obtained was filtered, washed, dried at 100 ° C for 3 hours and then calcined at 550 ° C for 2 hours. Then it was characterized by XRD, FTIR and TG. For the results of characterization has been observed that the use of the gravel drilling as a source of silica was promising alternative for producing a mesoporous material with a high degree of hexagonal ordering. (author)

  16. The study of methanol transformation over Cu-modified ZSM-5, Beta zeolite and MCM-41 mesoporous silica using 11C-radioisotope labeling

    International Nuclear Information System (INIS)

    Sarkadi-Priboczki, E.; Kovacs, Z.

    2004-01-01

    Complete text of publication follows. The copper-containing zeolites and mesoporous silica, among other metals, are suitable for dehydrogenation of methanol. The Cu transition metal determines the route of methanol conversion on supports of ZSM-5 and Beta zeolite as well as MCM-41 mesoporous silica. The catalysis mechanism and the catalytic property are concluded from the composition of methanol derivates over Cu-modified catalysts. The Cu ion-exchanged ZSM-5 and Beta zeolite and MCM-41 mesoporous silica were synthesized and characterized using X-ray power diffraction, scanning electron microscope, nitrogen and pyridine adsorption, X-ray fluorescency and FTIR spectroscopy. The 11 C-radioactive labeling method ( 11 C radioisotope, T 1/2 = 20 min, is a gamma emitter by annihilation of its positron) is suitable for following the process of 11 C-methanol con- version i.e. adsorption, desorption and catalytic transformation as well as for investigation of small amounts of molecules over catalysts by very sensitive radioactivity detectors.The 11 C radioisotope was produced at cyclotron and the 11 C-methanol was synthesized by a classical radiochemical method. After catalysis the 11 C-radioactive and non radioactive volatile products were identified by radiogas chromatography hereby radiolabeled compound and -derivates were distinguished from other participant natural, nonradioactive carbon compounds. Along radioactive products dimethyl ether and small hydrocarbons products were formed by Bronsted acid sites of catalysts while formaldehyde and small methyl formate were formed by Cu metal over bifunctional Cu-ZSM-5, Cu-Beta zeolite and mesoporous Cu-MCM-41 silica at 240 deg C. The detection of methoxy methanol and dimethoxy methane confirmed the simultaneous presence of acid and basic sites of catalysts. At higher temperature (400 deg C) the CO and CO 2 final products were dominated. In our previous works, methanol conversion to hydrocarbons was observed by dehydration

  17. Recovery of silica from electronic waste for the synthesis of cubic MCM-48 and its application in preparing ordered mesoporous carbon molecular sieves using a green approach

    Energy Technology Data Exchange (ETDEWEB)

    Liou, Tzong-Horng, E-mail: thliou@mail.mcut.edu.tw [Ming Chi University of Technology, Department of Chemical Engineering, Taiwan (China)

    2012-07-15

    The electronics industry is one of the world's fastest growing manufacturing industries. However, e-waste has become a serious pollution problem. This study reports the recovery of e-waste for preparing valuable MCM-48 and ordered mesoporous carbon for the first time. Specifically, this study adopts an alkali-extracted method to obtain sodium silicate precursors from electronic packaging resin ash. The influence of synthesis variables such as gelation pH, neutral/cationic surfactant ratio, hydrothermal treatment temperature, and calcination temperature on the mesophase of MCM-48 materials is investigated. Experimental results confirm that well-ordered cubic MCM-48 materials were synthesized in strongly acidic and strongly basic media. The resulting mesoporous silica had a high surface area of 1,317 m{sup 2}/g, mean pore size of about 3.0 nm, and a high purity of 99.87 wt%. Ordered mesoporous carbon with high surface area (1,715 m{sup 2}/g) and uniform pore size of CMK-1 type was successfully prepared by impregnating MCM-48 template using the resin waste. The carbon structure was sensitive to the sulfuric acid concentration and carbonization temperature. Converting e-waste into MCM-48 materials not only eliminates the disposal problem of e-waste, but also transforms industrial waste into a useful nanomaterial.

  18. The effects of 3-methylcholanthrene on lymphocyte proliferation in the common carp (Cyprinus carpio L.)

    International Nuclear Information System (INIS)

    Reynaud, S.; Deschaux, P.

    2005-01-01

    The sensitivity of lymphocyte proliferation as bioindicator of pollution stress was evaluated in the common carp (Cyrinus carpio L.). The time course response of peripheral blood leukocyte proliferation in response or not to mitogens was measured from 1 to 7 days after peritoneal injection of 3-methylcholantrene (3-MC), and compared to the time course response of a highly sensitive biomarker, induction of cytochrome P450. 3-Methylcholanthrene (40 mg kg -1 ) inhibited both B- and T-lymphocyte proliferation in response to lipopolysaccharide (LPS) and concanavalin A (Con A). Studies with α-naphtofiavone, suggest the lack of metabolic processes. 3-Methylcholanthrene alone strongly stimulated resting peripheral blood leukocytes (PBLs) proliferation. This effect was not transient. The induction of lymphocyte proliferation paralleled the increase in cytochrome P450 content in the liver. The specificity of polycyclic aromatic hydrocarbon (PAH)-induced lymphocyte proliferation suggests that this immune activity may be an early marker of exposure to PAHs in aquatic environments. The capacity of 3-MC to induce rapid lymphocyte proliferation may be related to PAH-induced rapid clonal expansion in mammals. These results strongly suggested that the underlying mechanism might be the same in both models. More studies are needed in fish to explain this phenomenon and may be helpful in understanding the occurrence of neoplastic epizootics in fish associated with PAH exposition

  19. Gas-phase Precursors to Anthropogenic SOA: Using the MCM to Probe Detailed Observations of Aromatic Photo-oxidation

    Science.gov (United States)

    Rickard, A. R.; Wyche, K. P.; Metzger, A.; Monks, P. S.; Ellis, A. M.; Baltensperger, U.; Pilling, M. J.; Jenkin, M. E.

    2008-12-01

    The formation of photochemical ozone and particulate matter are major priorities in the determination of European air quality policies. Predictions of the future state of the atmosphere and the development of appropriate mitigation strategies rely on models, which necessarily incorporate chemistry. The Master Chemical Mechanism (MCM, http://mcm.leeds.ac.uk/MCM) is a near-explicit chemical mechanism originally conceived to model ozone formation in Europe but now also employed as a benchmark mechanism in a wide variety of applications where chemical detail is required. The MCM currently describes the detailed gas- phase tropospheric degradation of a 135 primary emitted volatile organic compounds (VOCs) leading to a mechanism containing ca. 5900 species and 13500 reactions. In order that the MCM continues to be a state-of-the-art resource for the atmospheric science community it resides under a constant regime of evaluation, development and improvement. Individual VOC photochemical mechanisms are evaluated using data obtained, under a variety of atmospheric conditions, from highly instrumented smog chambers. Smog chamber experiments are crucial, not only for mechanism evaluation, but also for mechanism development. Findings obtained from combined model and chamber studies can additionally provide key insight for guiding the directions of future laboratory experiments. Recently, the MCM was updated to MCMv3.1 in order to take into account recent advancements in the understanding of aromatic photo-oxidation, an important class of anthropogenic VOCs. As well as constituting precursors to secondary organic aerosol (SOA), aromatics generally have high photochemical ozone creation potentials (POCPs) and hence contribute significantly towards tropospheric ozone formation. In the work presented, a detailed gas-phase photochemical chamber box model, incorporating the MCMv3.1 degradation mechanism for 1,3,5-trimethylbenzene (TMB), has been used to simulate data measured during

  20. Acidic and Catalytic Properties of Mo-MCM-22 in Methane Aromatization: An FTIR Study

    Czech Academy of Sciences Publication Activity Database

    Sobalík, Zdeněk; Tvarůžková, Zdenka; Wichterlová, Blanka; Fíla, V.; Špatenka, Š.

    2003-01-01

    Roč. 253, - (2003), s. 271-282 ISSN 0926-860X R&D Projects: GA ČR GA104/99/0432 Institutional research plan: CEZ:AV0Z4040901 Keywords : methane aromatization * FTIR technique * MCM-22 Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.825, year: 2003

  1. Antiproliferative effects of TSA, PXD‑101 and MS‑275 in A2780 and MCF7 cells: Acetylated histone H4 and acetylated tubulin as markers for HDACi potency and selectivity.

    Science.gov (United States)

    Androutsopoulos, Vasilis P; Spandidos, Demetrios A

    2017-12-01

    Inhibition of histone deacetylase enzymes (HDACs) has been well documented as an attractive target for the development of chemotherapeutic drugs. The present study investigated the effects of two prototype hydroxamic acid HDAC inhibitors, namely Trichostatin A (TSA) and Belinostat (PXD‑101) and the benzamide Entinostat (MS‑275) in A2780 ovarian carcinoma and MCF7 breast adenocarcinoma cells. The three HDACi inhibited the proliferation of A2780 and MCF7 cells at comparable levels, below the µM range. Enzyme inhibition assays in a cell‑free system showed that TSA was the most potent inhibitor of total HDAC enzyme activity followed by PXD‑101 and MS‑275. Incubation of A2780 and MCF7 cells with the hydroxamates TSA and PXD‑101 for 24 h resulted in a dramatic increase of acetylated tubulin induction (up to 30‑fold for TSA). In contrast to acetylated tubulin, western blot analysis and flow cytometry indicated that the induction of acetylated histone H4 was considerably smaller. The benzamide MS‑275 exhibited nearly a 2‑fold induction of acetylated histone H4 and an even smaller induction of acetylated tubulin in A2780 and MCF7 cells. Taken together, these data suggest that although the three HDACi were equipotent in inhibiting proliferation of MCF7 and A2780 cells, only the benzamide MS‑275 did not induce acetylated tubulin expression, a marker of class IIb HDACs.

  2. Optimization of MCM-48 synthesis using factorial design

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, A.R. do; Medeiros, R.L.B. de A.; Melo, M. A. de F.; Melo, D.M. de A. [Universitdade Federal do Rio Grande do Norte (UFRN), Natal (Brazil); Souza, M.J.B. de, E-mail: ale3ufs@yahoo.com.br [Universidade Federal de Sergipe (UFS), Sao Cristovao (Brazil)

    2016-10-15

    MCM-48 mesoporous materials were hydrothermally synthesized according to the 2{sup 2} factorial design by varying the crystallization time and temperature of the synthesis gel, and characterized by means of X-ray diffraction analysis and adsorption of N{sub 2} . In the crystallization temperature and time conditions used, specific areas between 924 to 1102 m{sup 2}.g{sup -1}, pore volumes between 0.015 to 0.087 cm{sup 3}.g{sup -1} and pore diameters between 3.2 to 4.0 nm were obtained. It was observed that for the syntheses performed at high temperature, the crystallization time should be reduced so that the material structure is formed. (author)

  3. Age-dependent acute interference with stem and progenitor cell proliferation in the hippocampus after exposure to 1800 MHz electromagnetic radiation.

    Science.gov (United States)

    Xu, Falin; Bai, Qiongdan; Zhou, Kai; Ma, Li; Duan, Jiajia; Zhuang, Fangli; Xie, Cuicui; Li, Wenli; Zou, Peng; Zhu, Changlian

    2017-01-01

    To investigate the effects of exposure to an 1800 MHz electromagnetic field on cell death and cell proliferation in the developing brain, postnatal day 7 (P7) and P21 healthy Kunming mice were randomly assigned into the experimental and control groups. The experimental groups were exposed to an 1800 MHz electromagnetic field for 8 h daily for three consecutive days. The thymidine analog 5-bromo-2-deoxyuridine (BrdU) was injected intraperitoneally 1 h before each exposure session, and all animals were sacrificed 24 h after the last exposure. Cell death and proliferation markers were detected by immunohistochemistry in the dentate gyrus of the hippocampus. Electromagnetic exposure has no influence on cell death in the dentate gyrus of the hippocampus in P7 and P21 mice as indicated by active caspase-3 immunostaining and Fluoro-Jade labeling. The basal cell proliferation in the hippocampus was higher in P7 than in P21 mice as indicated by the number of cells labeled with BrdU and by immunohistochemical staining for phosphor-histone H3 (PHH3) and brain lipid-binding protein (BLBP). Electromagnetic exposure stimulated DNA synthesis in P7 neural stem and progenitor cells, but reduced cell division and the total number of stem cells in the hippocampus as indicated by increased BrdU labeling and reduced PHH3 and BLBP labeling compared to P7 control mice. There were no significant changes in cell proliferation in P21 mice after exposure to the electromagnetic field. These results indicate that interference with stem cell proliferation upon short-term exposure to an 1800 MHz electromagnetic field depends on the developmental stage of the brain.

  4. 7-Piperazinethylchrysin inhibits melanoma cell proliferation by ...

    African Journals Online (AJOL)

    In B16F10 and A375 cells, treatment with PEC caused the inhibition ... Conclusion: PEC inhibited melanoma cell proliferation, apparently by blocking the cell cycle at G0/G1 .... all statistical analyses. .... Financial support from the Department of.

  5. Protein kinase D1 stimulates proliferation and enhances tumorigenesis of MCF-7 human breast cancer cells through a MEK/ERK-dependent signaling pathway

    International Nuclear Information System (INIS)

    Karam, Manale; Legay, Christine; Auclair, Christian; Ricort, Jean-Marc

    2012-01-01

    Protein kinase D1, PKD1, is a novel serine/threonine kinase whose altered expression and dysregulation in many tumors as well as its activation by several mitogens suggest that this protein could regulate proliferation and tumorigenesis. Nevertheless, the precise signaling pathways used are still unclear and the potential direct role of PKD1 in tumor development and progression has not been yet investigated. In order to clarify the role of PKD1 in cell proliferation and tumorigenesis, we studied the effects of PKD1 overexpression in a human adenocarcinoma breast cancer cell line, MCF-7 cells. We demonstrated that overexpression of PKD1 specifically promotes MCF-7 cell proliferation through accelerating G0/G1 to S phase transition of the cell cycle. Moreover, inhibition of endogenous PKD1 significantly reduced cell proliferation. Taken together, these results clearly strengthen the regulatory role of PKD1 in cell growth. We also demonstrated that overexpression of PKD1 specifically diminished serum- and anchorage-dependence for proliferation and survival in vitro and allowed MCF-7 cells to form tumors in vivo. Thus, all these data highlight the central role of PKD1 in biological processes which are hallmarks of malignant transformation. Analysis of two major signaling pathways implicated in MCF-7 cell proliferation showed that PKD1 overexpression significantly increased ERK1/2 phosphorylation state without affecting Akt phosphorylation. Moreover, PKD1 overexpression-stimulated cell proliferation and anchorage-independent growth were totally impaired by inhibition of the MEK/ERK kinase cascade. However, neither of these effects was affected by blocking the PI 3-kinase/Akt signaling pathway. Thus, the MEK/ERK signaling appears to be a determining pathway mediating the biological effects of PKD1 in MCF-7 cells. Taken together, all these data demonstrate that PKD1 overexpression increases the aggressiveness of MCF-7 breast cancer cells through enhancing their oncogenic

  6. The proliferation marker pKi-67 becomes masked to MIB-1 staining after expression of its tandem repeats.

    Science.gov (United States)

    Schmidt, Mirko H H; Broll, Rainer; Bruch, Hans-Peter; Duchrow, Michael

    2002-11-01

    The Ki-67 antigen, pKi-67, is one of the most commonly used markers of proliferating cells. The protein can only be detected in dividing cells (G(1)-, S-, G(2)-, and M-phase) but not in quiescent cells (G(0)). The standard antibody to detect pKi-67 is MIB-1, which detects the so-called 'Ki-67 motif' FKELF in 9 of the protein's 16 tandem repeats. To investigate the function of these repeats we expressed three of them in an inducible gene expression system in HeLa cells. Surprisingly, addition of a nuclear localization sequence led to a complete absence of signal in the nuclei of MIB-1-stained cells. At the same time antibodies directed against different epitopes of pKi-67 did not fail to detect the protein. We conclude that the overexpression of the 'Ki-67 motif', which is present in the repeats, can lead to inability of MIB-1 to detect its antigen as demonstrated in adenocarcinoma tissue samples. Thereafter, in order to prevent the underestimation of Ki-67 proliferation indices in MIB-1-labeled preparations, additional antibodies (for example, MIB-21) should be used. Additionally, we could show in a mammalian two-hybrid assay that recombinant pKi-67 repeats are capable of self-associating with endogenous pKi-67. Speculating that the tandem repeats are intimately involved in its protein-protein interactions, this offers new insights in how access to these repeats is regulated by pKi-67 itself.

  7. Partial hydrogenation of alkynes on highly selective nano-structured mesoporous silica MCM-41 composite catalyst

    International Nuclear Information System (INIS)

    Kojoori, R.K.

    2016-01-01

    In this research, we have developed a silica MCM-41/Metformin/Pd (II) nano composite catalyst for the selective hydrogenation of alkynes to the corresponding (Z)-alkenes under a mild condition of atmospheric pressure and room temperature. Firstly, functionalized Si-MCM-41 metformin catalyst with the optimum performance was prepared. Then, the synthesized catalyst was elucidated by X-ray powder diffraction, BET surface area, FT-IR spectrophotometer, Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) and applied in partial hydrogenation of different alkynes, with high selectivity and high yield. The products were characterized by 1H-NMR, 13C-NMR, FT-IR, and Mass Spectrometry (MS) that strongly approved the (Z)-double bond configuration of produced alkenes. This prepared catalyst is competitive with the best palladium catalysts known for the selective liquid phase hydrogenation of alkynes and can be easily recovered and regenerated with keeping high activity and selectivity over at least three cycles with a simple regeneration procedure. (author)

  8. Synthesis of AL-MCM-41 using gravel drilling the source of silica from wells drilling

    International Nuclear Information System (INIS)

    Fontes, M.S.B.; Costa, C.C.; Melo, D.M.A.; Viana, L.M.; Viana, S.O.; Santos, L.M.

    2016-01-01

    The aim of this study was to synthesize Al-MCM-41 using gravel drilling as alternative source of silica, aiming at sustainable production and low cost. For hydrothermal synthesis of Al-MCM-41 was used gravel and sodium silicate as source of silica and sodium, respectively. The structural driver used was cetyltrimethylammonium bromide (CTMABr) and solvent distilled water. The hydrothermal synthesis was conducted at 100 ° C in a Teflon autoclave 45 ml jacketed stainless steel for a period of 120 hours with daily correcting pH (range 9-10) using 30% acetic acid. The material obtained was filtered, washed, dried at 100 ° C for 3 hours and then calcined at 550 ° C for 2 hours. Then it was characterized by XRD, FTIR and TG. For the results of characterization has been observed that the use of the gravel drilling as a source of silica was promising alternative for producing a mesoporous material with a high degree of hexagonal ordering. (author)

  9. Reduction of tobacco smoke components yield in commercial cigarette brands by addition of HUSY, NaY and Al-MCM-41 to the cigarette rod.

    Science.gov (United States)

    Marcilla, A; Gómez-Siurana, A; Berenguer, D; Martínez-Castellanos, I; Beltrán, M I

    2015-01-01

    The effect of two zeolites, HUSY, NaY and a mesoporous synthesized Al-MCM-41 material on the smoke composition of ten commercial cigarettes brands has been studied. Cigarettes were prepared by mixing the tobacco with the three powdered materials, and the smoke obtained under the ISO conditions was analyzed. Up to 32 compounds were identified and quantified in the gas fraction and 80 in the total particulate matter (TPM) condensed in the cigarettes filters and in the traps located after the mouth end of the cigarettes. Al-MCM-41 is by far the best additive, providing the highest reductions of the yield for most compounds and brands analyzed. A positive correlation was observed among the TPM and nicotine yields with the reduction obtained in nicotine, CO, and most compounds with the three additives. The amount of ashes in additive free basis increases due to the coke deposited on the solids, especially with Al-MCM-41. Nicotine is reduced with Al-MCM-41 by an average of 34.4% for the brands studied (49.5% for the brand where the major reduction was obtained and 18.5 for the brand behaving the worst). CO is reduced by an average of 18.6% (ranging from 10.3 to 35.2% in the different brands).

  10. First MCM-D modules for the b-physics layer of the ATLAS Pixel Detector

    CERN Document Server

    Basken, O; Ehrmann, O; Gerlach, P; Grah, C; Gregor, I M; Linder, C; Meuser, S; Richardson, J; Topper, M; Wolf, J

    2000-01-01

    The innermost layer (b-physics layer) of the ATLAS Pixel Detector will consist of modules based on MCM-D technology. Such a module consists of a sensor tile with an active area of 16.4 mm*60.4 mm, 16 read out ICs, each serving 24* 160 pixel unit cells, a module controller chip (MCC), an optical transceiver and the local signal interconnection and power distribution busses. We show a prototype of such a module with additional test pads on both sides. The outer dimensions of the final module will be 21.4 mm*67.8 mm. The extremely high wiring density, which is necessary to interconnect the read-out chips, was achieved using a thin film copper/photo-BCB process on the pixel array. The bumping of the read out chips was done using electroplating PbSn. All dice are then attached by flip-chip assembly to the sensor diodes and the local busses. The focus of this paper is the description of the first results of such MCM-D-type modules. (11 refs).

  11. Estrogen induced {beta}-1,4-galactosyltransferase 1 expression regulates proliferation of human breast cancer MCF-7 cells

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hee-Jung [Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan (Korea, Republic of); Division of Applied Medicine, School of Korean Medicine, Pusan National University, Yangsan-city, Gyeongsangnam-do (Korea, Republic of); Chung, Tae-Wook; Kim, Cheorl-Ho [Department of Molecular and Cellular Glycobiology, College of Natural Science, Sungkyunkwan University, Suwon, Kyungki-do (Korea, Republic of); Jeong, Han-Sol; Joo, Myungsoo [Division of Applied Medicine, School of Korean Medicine, Pusan National University, Yangsan-city, Gyeongsangnam-do (Korea, Republic of); Youn, BuHyun, E-mail: bhyoun72@pusan.ac.kr [Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan (Korea, Republic of); Ha, Ki-Tae, E-mail: hagis@pusan.ac.kr [Division of Applied Medicine, School of Korean Medicine, Pusan National University, Yangsan-city, Gyeongsangnam-do (Korea, Republic of)

    2012-10-05

    Highlights: Black-Right-Pointing-Pointer We examined the regulation and biological functions of B4GALT1 expression induced by estrogen. Black-Right-Pointing-Pointer Estrogen-induced B4GALT1 expression through the direct binding of ER-{alpha} to ERE in MCF-7 cells. Black-Right-Pointing-Pointer B4GALT1 expression activates the proliferation of MCF-7 cells via its receptor function. Black-Right-Pointing-Pointer Thus, we suggest B4GALT1 as a molecular target for inhibiting breast cancer proliferation. -- Abstract: Beta 1,4-galactosyltransferase 1 (B4GALT1) synthesizes galactose {beta}-1,4-N-acetylglucosamine (Gal{beta}1-4GlcNAc) groups on N-linked sugar chains of glycoproteins, which play important roles in many biological events, including the proliferation and migration of cancer cells. A previous microarray study reported that this gene is expressed by estrogen treatment in breast cancer. In this study, we examined the regulatory mechanisms and biological functions of estrogen-induced B4GALT1 expression. Our data showed that estrogen-induced expression of B4GALT1 is localized in intracellular compartments and in the plasma membrane. In addition, B4GALT1 has an enzyme activity involved in the production of the Gal{beta}1-4GlcNAc structure. The result from a promoter assay and chromatin immunoprecipitation revealed that 3 different estrogen response elements (EREs) in the B4GALT1 promoter are critical for responsiveness to estrogen. In addition, the estrogen antagonists ICI 182,780 and ER-{alpha}-ERE binding blocker TPBM inhibit the expression of estrogen-induced B4GALT1. However, the inhibition of signal molecules relating to the extra-nuclear pathway, including the G-protein coupled receptors, Ras, and mitogen-activated protein kinases, had no inhibitory effects on B4GALT1 expression. The knock-down of the B4GALT1 gene and the inhibition of membrane B4GALT1 function resulted in the significant inhibition of estrogen-induced proliferation of MCF-7 cells. Considering

  12. Estrogen induced β-1,4-galactosyltransferase 1 expression regulates proliferation of human breast cancer MCF-7 cells

    International Nuclear Information System (INIS)

    Choi, Hee-Jung; Chung, Tae-Wook; Kim, Cheorl-Ho; Jeong, Han-Sol; Joo, Myungsoo; Youn, BuHyun; Ha, Ki-Tae

    2012-01-01

    Highlights: ► We examined the regulation and biological functions of B4GALT1 expression induced by estrogen. ► Estrogen-induced B4GALT1 expression through the direct binding of ER-α to ERE in MCF-7 cells. ► B4GALT1 expression activates the proliferation of MCF-7 cells via its receptor function. ► Thus, we suggest B4GALT1 as a molecular target for inhibiting breast cancer proliferation. -- Abstract: Beta 1,4-galactosyltransferase 1 (B4GALT1) synthesizes galactose β-1,4-N-acetylglucosamine (Galβ1-4GlcNAc) groups on N-linked sugar chains of glycoproteins, which play important roles in many biological events, including the proliferation and migration of cancer cells. A previous microarray study reported that this gene is expressed by estrogen treatment in breast cancer. In this study, we examined the regulatory mechanisms and biological functions of estrogen-induced B4GALT1 expression. Our data showed that estrogen-induced expression of B4GALT1 is localized in intracellular compartments and in the plasma membrane. In addition, B4GALT1 has an enzyme activity involved in the production of the Galβ1-4GlcNAc structure. The result from a promoter assay and chromatin immunoprecipitation revealed that 3 different estrogen response elements (EREs) in the B4GALT1 promoter are critical for responsiveness to estrogen. In addition, the estrogen antagonists ICI 182,780 and ER-α-ERE binding blocker TPBM inhibit the expression of estrogen-induced B4GALT1. However, the inhibition of signal molecules relating to the extra-nuclear pathway, including the G-protein coupled receptors, Ras, and mitogen-activated protein kinases, had no inhibitory effects on B4GALT1 expression. The knock-down of the B4GALT1 gene and the inhibition of membrane B4GALT1 function resulted in the significant inhibition of estrogen-induced proliferation of MCF-7 cells. Considering these results, we propose that estrogen regulates the expression of B4GALT1 through the direct binding of ER-α to ERE and

  13. Homeostatic Proliferation and IL-7R Alpha Expression Do Not Correlate with Enhanced T Cell Proliferation and Protection in Chronic Mouse Malaria

    OpenAIRE

    Stephens, Robin; Seddon, Benedict; Langhorne, Jean

    2011-01-01

    While chronic infection has been shown to enhance protection from disease caused by several pathogens, the mechanisms are not known. The gamma-c family of cytokines IL-7, IL-2, and IL-15 are implicated in homeostatic proliferation, which is thought to maintain T cell memory. However in chronic infection, prolonged antigen exposure itself may contribute to lymphocyte survival. We have previously observed that chronic malaria infection enhances protection to re-infection, as well as enhancing B...

  14. Sonogashira Reaction of Aryl and Heteroaryl Halides with Terminal Alkynes Catalyzed by a Highly Efficient and Recyclable Nanosized MCM-41 Anchored Palladium Bipyridyl Complex

    Directory of Open Access Journals (Sweden)

    Chung-Yuan Mou

    2010-12-01

    Full Text Available A heterogeneous catalyst, nanosized MCM-41-Pd, was used to catalyze the Sonogashira coupling of aryl and heteroaryl halides with terminal alkynes in the presence of CuI and triphenylphosphine. The coupling products were obtained in high yields using low Pd loadings to 0.01 mol%, and the nanosized MCM-41-Pd catalyst was recovered by centrifugation of the reaction solution and re-used in further runs without significant loss of reactivity.

  15. Co-modified MCM-41 as an effective adsorbent for levofloxacin removal from aqueous solution: optimization of process parameters, isotherm, and thermodynamic studies.

    Science.gov (United States)

    Jin, Ting; Yuan, Wenhua; Xue, Yujie; Wei, Hong; Zhang, Chaoying; Li, Kebin

    2017-02-01

    Antibiotics are emerging contaminants due to their potential risks to human health and ecosystems. Poor biodegradability makes it necessary to develop effective physical-chemical methods to eliminate these contaminants from water. The cobalt-modified MCM-41 was prepared by a one-pot hydrothermal method and characterized by SAXRD, N 2 adsorption-desorption, SEM, UV-Vis DR, and FTIR spectroscopy. The results revealed that the prepared 3% Co-MCM-41 possessed mesoporous structure with BET surface areas at around 898.5 m 2 g -1 . The adsorption performance of 3% Co-MCM-41 toward levofloxacin (LVF) was investigated by batch experiments. The adsorption of LVF on 3% Co-MCM-41 was very fast and reached equilibrium within 2 h. The adsorption kinetics followed the pseudo-second-order kinetic model with the second-order rate constants in the range of 0.00198-0.00391 g mg -1  min -1 . The adsorption isotherms could be well represented by the Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherm equations. Nevertheless, D-R isotherm provided the best fit based on the coefficient of determination and average relative error values. The mean free energy of adsorption (E) calculated from D-R model was about 11 kJ mol -1 , indicating that the adsorption was mainly governed by a chemisorption process. Moreover, the adsorption capacity was investigated as a function of pH, adsorbent dosage, LVF concentration, and temperature with help of respond surface methodology (RSM). A quadratic model was established, and an optimal condition was obtained as follows: pH 8.5, adsorbent dosage of 1 g L -1 , initial LVF concentration of 119.8 mg L -1 , and temperature of 31.6 °C. Under the optimal condition, the adsorption capacity of 3% Co-MCM-41 to LVF could reach about 108.1 mg g -1 . The solution pH, adsorbent dosage, LVF concentration, and a combination of adsorbent dose and LVF concentration were significant factors affecting the adsorption process. The adsorption

  16. Association between expression of cumulus expansion markers and real-time proliferation of porcine follicular granulosa cells in a primary cell culture model.

    Science.gov (United States)

    Ciesiółka, S; Budna, J; Bryja, A; Kranc, W; Chachuła, A; Dyszkiewicz-Konwińska, M; Piotrowska, H; Bukowska, D; Antosik, P; Bruska, M; Brüssow, K P; Nowicki, M; Zabel, M; Kempisty, B

    2016-01-01

    Folliculogenesis is a compound process that involves both ovarian follicle growth and oocyte development, which is tightly attached to the follicular wall. During this process, cells that form the follicle structure undergo substantial morphological and molecular modifications that finally lead to differentiation and specialization of ovarian follicular cells. The differentiation of ovarian cells encompasses formation of follicle, which is composed of theca (TCs), mural granulosa (GCs), and cumulus cells (CCs). It was previously hypothesized that GCs and CCs represent undifferentiated and highly specialized follicular cells, respectively, which may have similar primordial cell origins. In this study, we investigated the expression pattern of cumulus expansion markers such as COX2, HAS2, PTX3, and TSG6 in porcine GCs during short-term, in vitro culture. We hypothesized that these genes may display an important function in GCs in relation to cellular real-time proliferation. The expression pattern of COX2, HAS2, PTX3, and TSG6 was evaluated after using RT-qPCR in relation to confocal microscopy observations of protein expression and distribution during real-time proliferation of porcine follicular GCs. The COX2 and HAS2 mRNAs were highly expressed after 120 h of in vitro culture (IVC), whereas PTX3 and TSG6 mRNAs were increased during the first 24-48 h of IVC (P less than 0.001, P less than 0.01). Conversely, all of the encoded proteins were highly expressed after 144-168 h of IVC as compared to other culture periods (P less than 0.001, P less than 0.01). When analyzing the realtime proliferation of GCs in vitro, we observed a logarithmic increase of cell proliferation between 0 h and 120 h of IVC. However, after 120-168 h of IVC, the cells reached the lag phase of proliferation. Since it is well accepted that porcine GCs undergo luteinization shortly after 24-48 h of IVC, the expression pattern of investigated genes indicated that Cox2 and Has2 are independent from

  17. Nicotine promotes cell proliferation and induces resistance to cisplatin by α7 nicotinic acetylcholine receptor‑mediated activation in Raw264.7 and El4 cells.

    Science.gov (United States)

    Wang, Yan Yan; Liu, Yao; Ni, Xiao Yan; Bai, Zhen Huan; Chen, Qiong Yun; Zhang, Ye; Gao, Feng Guang

    2014-03-01

    Although nicotine is a risk factor for carcinogenesis and atherosclerosis, epidemiological data indicate that nicotine has therapeutic benefits in treating Alzheimer's disease. Our previous studies also showed that nicotine-treated dendritic cells have potential antitumor effects. Hence, the precise effects of nicotine on the biological characterizations of cells are controversial. The aim of the present study was to assess the roles of α7 nicotinic acetylcholine receptors (nAChRs), Erk1/2-p38-JNK and PI3K-Akt pathway in nicotine-mediated proliferation and anti-apoptosis effects. The results firstly showed that nicotine treatment clearly augmented cell viability and upregulated PCNA expression in both Raw264.7 and El4 cells. Meanwhile, nicotine afforded protection against cisplatin-induced toxicity through inhibiting caspase-3 activation and upregulating anti-apoptotic protein expression. Further exploration demonstrated that nicotine efficiently abolished cisplatin-promoted mitochondria translocation of Bax and the release of cytochrome c. The pretreatment of α-bungarotoxin and tubocurarine chloride significantly attenuated nicotine-augmented cell viability, abolished caspase-3 activation and α7 nAChR upregulation. Both Erk-JNK-p38 and PI3K-Akt signaling pathways could be activated by nicotine treatment in Raw264.7 and El4 cells. Notably, when Erk-JNK and PI3K-Akt activities were inhibited, nicotine-augmented cell proliferation and anti-apoptotic effects were abolished accordingly. The results presented here indicate that nicotine could achieve α7 nAChR-mediated proliferation and anti-apoptotic effects by activating Erk-JNK and PI3K-Akt pathways respectively, providing potential therapeutic molecules to deal with smoking-associated human diseases.

  18. Síntese do material mesoporoso MCM-41 usando esponja de água-doce como fonte de sílica

    Directory of Open Access Journals (Sweden)

    Orivaldo da Silva Lacerda Júnior

    2013-01-01

    Full Text Available Fresh water sponge was used as a silica source for the synthesis of MCM-41 via the hydrothermal process. The silica was extracted from the sponge by washing with nitric acid and piranha solution. Synthesis of MCM-41 was performed at 100 °C for 5 days and the procedure was optimized, with modifications made to the leaching temperature of the silica and the synthesis of mesoporous material, which was characterized by XRD, FT-IR, SEM and adsorption of N2. The optimal result was achieved at a temperature of 135 °C for 3 days, showing ordered mesoporous material with a surface area of 1080 m² g-1.

  19. Rapid modifications of peripheral T-cell subsets that express CD127 in macaques treated with recombinant IL-7.

    Science.gov (United States)

    Dereuddre-Bosquet, Nathalie; Vaslin, Bruno; Delache, Benoit; Brochard, Patricia; Clayette, Pascal; Aubenque, Céline; Morre, Michel; Assouline, Brigitte; Le Grand, Roger

    2007-08-01

    Interleukin-7 (IL-7) is a key regulator of thymopoiesis and T-cell homeostasis, which increases blood T-cell number by enhancing thymic output of naive cells and peripheral proliferation. We explored the effects of unglycosylated recombinant simian IL-7 (rsIL-7) administration on peripheral T-cell subpopulations in healthy macaques. RsIL-7 was well tolerated. Mean half-life ranged between 9.3 and 13.9 hours. Blood CD3(+)CD4(+) and CD3(+)CD8(+) lymphocyte counts decreased rapidly after each rsIL-7 administration, the duration of these effects being dependent on the frequency of administration. At treatment completion, the increased of CD3(+) lymphocytes was marked at 100 microg/kg every 2 days. CD3(+) lymphocytes that harbour the alpha chain of IL-7 receptor (CD127) and CD3(+)CD8(+) lymphocytes that expressed the proliferation marker Ki-67 exhibited a similar initial profile. The expression of the anti-apoptotic marker Bcl-2 increased in CD3(+) lymphocytes during the treatment and post-treatment period in a dose/frequency dependent manner. RsIL-7 was well tolerated in macaques and induces rapid modifications of T-cells that express CD127.

  20. Novedoso método para preparar materiales nanoporosos compuestos MFI/MCM-41 a partir de caolín venezolano. Efecto de la concentración de NaOH

    Directory of Open Access Journals (Sweden)

    Freddy Imbert

    2012-05-01

    Full Text Available A MFI/MCM-41 composite material, a zeolite type MFI and Al-MCM-41 were synthesized from kaolin, using TPA and CTAB as structure directing agents. The MFI/MCM-41 composite material was synthesized in two steps. In the first, MFI was obtained and then treated with solutions of different NaOH concentrations (1 – 4M, in the second step the reaction mixture was treated under MCM-41 synthesis conditions. The solids obtained were characterized by scanning electron microscopy (SEM, chemical analysis by energy dispersive X-ray spectroscopy (EDX, transmission electron microscopy (TEM, adsorption of N2 at 77K, X-ray diffraction (XRD. In the absence of alkaline treatment two phases were observed – zeolite and mesoporous, whereas the zeolite crystals were larger than mesoporous particles. The alkaline treatment dissolved the zeolite structure creating mesoporosity, modifying the characteristic zeolite morphology and reducing its crystal domains. The treatment with 2 or 3M NaOH eases zeolite dissolution and leads to assemble of the zeolite building units around the surfactant and into the mesoporous walls. The incorporation of the zeolite building units into the mesoporous walls is governed by the relative quantities of crystalline and amorphous materials in the synthesis gel. The treatment with 4M NaOH led exclusively to the formation of Al-MCM-41.

  1. Acute inactivation of the replicative helicase in human cells triggers MCM8-9-dependent DNA synthesis

    DEFF Research Database (Denmark)

    Natsume, Toyoaki; Nishimura, Kohei; Minocherhomji, Sheroy

    2017-01-01

    stemming from replisome dissociation during DNA replication perturbation, we used a degron-based system for inducible proteolysis of a subunit of the replicative helicase. We show that MCM2-depleted cells activate a DNA damage response pathway and generate replication-associated DNA double-strand breaks...

  2. Effect of punicalagin on proliferation of porcine ovarian granulosa cells in vitro

    Directory of Open Access Journals (Sweden)

    Dagmara Packová

    2016-12-01

    Full Text Available Punicalagin is a major component responsible for pomegranate's (Punica granatum antioxidant properties. Punicalagin is the predominant ellagitannin of Punica granatum and present in two isomeric forms: punicalagin α and β. Punicalagin is metabolised to ellagic acid (antioxidant and microorganisms present in colon can metabolize ellagic acid to urolithins. The aim of in vitro study was to examine the effect of punicalagin on mitochondrial activity and markers of proliferation in porcine ovarian granulosa cells. The cells were cultivated during 24h without (control group and with various doses (0.01, 0.1, 1, 10 and 100 μg*ml-1 of pomegranate compound – punicalagin. MTT assay and immunocytochemistry were used in this study. Stimulatory influence of punicalagin on the mitochondrial activity of ovarian granulosa cells at concentrations 1 μg*ml-1 was found. Punicalagin (at 1 μg*ml-1 had a significant (P < 0.05 impact on the presence of proliferative markers cyclin B1 (increase and PCNA - proliferating cell nuclear antigen (decrease in porcine ovarian granulosa cells. These results suggest dose-dependent effect of punicalagin on cell proliferation. Further verification of possible role of punicalagin in proliferation is therefore needed.

  3. Reduction of tobacco smoke components yield in commercial cigarette brands by addition of HUSY, NaY and Al-MCM-41 to the cigarette rod

    Directory of Open Access Journals (Sweden)

    A. Marcilla

    2015-01-01

    Full Text Available The effect of two zeolites, HUSY, NaY and a mesoporous synthesized Al-MCM-41 material on the smoke composition of ten commercial cigarettes brands has been studied. Cigarettes were prepared by mixing the tobacco with the three powdered materials, and the smoke obtained under the ISO conditions was analyzed. Up to 32 compounds were identified and quantified in the gas fraction and 80 in the total particulate matter (TPM condensed in the cigarettes filters and in the traps located after the mouth end of the cigarettes. Al-MCM-41 is by far the best additive, providing the highest reductions of the yield for most compounds and brands analyzed. A positive correlation was observed among the TPM and nicotine yields with the reduction obtained in nicotine, CO, and most compounds with the three additives. The amount of ashes in additive free basis increases due to the coke deposited on the solids, especially with Al-MCM-41. Nicotine is reduced with Al-MCM-41 by an average of 34.4% for the brands studied (49.5% for the brand where the major reduction was obtained and 18.5 for the brand behaving the worst. CO is reduced by an average of 18.6% (ranging from 10.3 to 35.2% in the different brands.

  4. Prognostic value of proliferating cell nuclear antigen in parotid gland cancer.

    Science.gov (United States)

    Stenner, Markus; Demgensky, Ariane; Molls, Christoph; Hardt, Aline; Luers, Jan C; Grosheva, Maria; Huebbers, Christian U; Klussmann, Jens P

    2012-04-01

    Although cell proliferation is related to tumour aggressiveness and prognosis, there are few studies describing the expression of proliferative markers in salivary gland cancer. Our aim was to assess the long-term prognostic value of the proliferating cell nuclear antigen (PCNA) in a large group of histologically different salivary gland cancers. We analysed the expression of PCNA in 159 patients with parotid gland cancer by means of immunohistochemistry. The mean follow-up time was 56.6 months. A high expression of PCNA showed a significant correlation to the patients' pathological lymph node stage (p = 0.004). A high PCNA expression significantly indicated a poor 5-year disease-free (p = 0.046) and overall survival rate (p = 0.018). The PCNA expression was the only prognostic factor for a worse 5-year disease-free and overall survival in acinic cell carcinomas (p = 0.004, p = 0.022). The correlation between PCNA expression and survival probabilities of salivary gland cancer might make proliferation markers helpful tools in patient follow-up, prognosis and targeted therapy in salivary gland cancer in future.

  5. Epoxidation of natural limonene extracted from orange peels with hydrogen peroxide over Ti-MCM-41 catalyst

    Directory of Open Access Journals (Sweden)

    Wróblewska Agnieszka

    2018-03-01

    Full Text Available The paper presents the oxidation of natural limonene (extracted from waste orange peels by 60 wt% hydrogen peroxide, in the presence of Ti-MCM-41 catalyst and in methanol as the solvent. The aim of the research was to develop the most favorable technological parameters for the process of limonene oxidation (temperature, molar ratio of limonene to hydrogen peroxide, methanol concentration, Ti-MCM-41 catalyst content and reaction time by analyzing changes in the main functions describing this process: the conversion of limonene, selectivities of appropriate products, the conversion of hydrogen peroxide and the effective conversion of hydrogen peroxide. The process is environmentally friendly process and it uses renewable raw material - limonene and a safe oxidant -hydrogen peroxide. During the study, very valuable oxygenated derivatives of limonene were obtained: 1,2-epoxylimonene, its diol, carvone, carveol, and perillyl alcohol. These compounds are used in medicine, cosmetics, perfumery, food and polymers industries.

  6. MCM-41介孔碳材料的合成及其电化学性能%Synthesis of MCM-41 Mesoporous Carbon Materials and Their Electrochemical Performance

    Institute of Scientific and Technical Information of China (English)

    宋伟明; 徐立洋; 孙立; 邓启刚; 冯建; 程晓宇

    2017-01-01

    以十六烷基三甲基溴化铵(CTAB)为模板剂,可溶性淀粉(Starch)为碳源,通过软模板法一步合成了高度有序的介孔碳材料.通过热重分析(TG)、X射线衍射(XRD)、N2吸附-脱附和透射电子显微镜(TEM)对材料的结构进行了表征.结果表明:当m(模板剂CTAB)∶m(可溶性淀粉)=1.0∶1.5,650℃焙烧碳化3h,并用氢氟酸去除二氧化硅后,所得到的MCM-41有序介孔碳材料(OMC-650)的比表面积为985 m2/g,平均孔径为2.5nm,且孔径分布均匀.XRD和FEM分析结果表明,OMC-650具有典型的MCM-41结构特征,有序性良好.以OMC-650作为工作电极,氧化汞为参比电极,铂为辅助电极,用6 mol/L KOH做电解液,测其比电容为150 F/g,且经过1 000次充放电循环后,其比电容仍为138 F/g,为原电容的92%,说明所合成的材料具有良好的电容稳定性.%A highly ordered mesoporous carbon material was synthesized by a soft template method with hexadecyltrimethylammonium bromide (CTAB) as a template and soluble starch (Starch) as a carbon source.The structures of the resultant materials were characterized by thermal gravimetric analysis (TG),X-ray diffraction (XRD),N2 adsorption-desorption isotherms and transmission electron microscopy (TEM).The results showed that MCM-41 ordered mesoporous carbon material (OMC-650) was obtained when the mass ratio of CTAB to Starch was 1.0∶1.5,carbonized for 3 h at 650 ℃,and then removing the silica with hydrofluoric acid.OMC-650 possessed specific surface area of 985 m2/g and average pore diameter of 2.5 nm and exhibited a uniform distribution.XRD and TEM analysis showed that OMC-650 possesses a typical MCM-41 structural feature with high ordered structure.The electrochemical tests were conducted in a three-electrode system in 6 mol/L KOH solution.When OMC-650 was used as a working electrode,mercury oxide electrode was used as a reference electrode,and Pt wire electrode served as an auxiliary electrode.The specific capacitance of

  7. Nicotine promotes cell proliferation via α7-nicotinic acetylcholine receptor and catecholamine-synthesizing enzymes-mediated pathway in human colon adenocarcinoma HT-29 cells

    International Nuclear Information System (INIS)

    Wong, Helen Pui Shan; Yu Le; Lam, Emily Kai Yee; Tai, Emily Kin Ki; Wu, William Ka Kei; Cho, Chi Hin

    2007-01-01

    Cigarette smoking has been implicated in colon cancer. Nicotine is a major alkaloid in cigarette smoke. In the present study, we showed that nicotine stimulated HT-29 cell proliferation and adrenaline production in a dose-dependent manner. The stimulatory action of nicotine was reversed by atenolol and ICI 118,551, a β 1 - and β 2 -selective antagonist, respectively, suggesting the role of β-adrenoceptors in mediating the action. Nicotine also significantly upregulated the expression of the catecholamine-synthesizing enzymes [tyrosine hydroxylase (TH), dopamine-β-hydroxylase (DβH) and phenylethanolamine N-methyltransferase]. Inhibitor of TH, a rate-limiting enzyme in the catecholamine-biosynthesis pathway, reduced the actions of nicotine on cell proliferation and adrenaline production. Expression of α7-nicotinic acetylcholine receptor (α7-nAChR) was demonstrated in HT-29 cells. Methyllycaconitine, an α7-nAChR antagonist, reversed the stimulatory actions of nicotine on cell proliferation, TH and DβH expression as well as adrenaline production. Taken together, through the action on α7-nAChR nicotine stimulates HT-29 cell proliferation via the upregulation of the catecholamine-synthesis pathway and ultimately adrenaline production and β-adrenergic activation. These data reveal the contributory role α7-nAChR and β-adrenoceptors in the tumorigenesis of colon cancer cells and partly elucidate the carcinogenic action of cigarette smoke on colon cancer

  8. Dehydration of xylose to furfural over MCM-41-supported niobium-oxide catalysts.

    Science.gov (United States)

    García-Sancho, Cristina; Sádaba, Irantzu; Moreno-Tost, Ramón; Mérida-Robles, Josefa; Santamaría-González, José; López-Granados, Manuel; Maireles-Torres, Pedro

    2013-04-01

    A series of silica-based MCM-41-supported niobium-oxide catalysts are prepared, characterized by using XRD, N2 adsorption-desorption, X-ray photoelectron spectroscopy, Raman spectroscopy, and pyridine adsorption coupled to FTIR spectroscopy, and tested for the dehydration of D-xylose to furfural. Under the operating conditions used all materials are active in the dehydration of xylose to furfural (excluding the MCM-41 silica support). The xylose conversion increases with increasing Nb2 O5 content. At a loading of 16 wt % Nb2 O5 , 74.5 % conversion and a furfural yield of 36.5 % is achieved at 170 °C, after 180 min reaction time. Moreover, xylose conversion and furfural yield increase with the reaction time and temperature, attaining 82.8 and 46.2 %, respectively, at 190 °C and after 100 min reaction time. Notably, the presence of NaCl in the reaction medium further increases the furfural yield (59.9 % at 170 °C after 180 min reaction time). Moreover, catalyst reutilization is demonstrated by performing at least three runs with no loss of catalytic activity and without the requirement for an intermediate regeneration step. No significant niobium leaching is observed, and a relationship between the structure of the catalyst and the activity is proposed. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Quaternary ammonium-functionalized MCM-48 mesoporous silica as a sorbent for the dispersive solid-phase extraction of endocrine disrupting compounds in water.

    Science.gov (United States)

    Zhang, Shijuan; Lu, Fengli; Ma, Xiaoyun; Yue, Mingbo; Li, Yanxin; Liu, Jiammin; You, Jinmao

    2018-07-06

    MCM-48 mesoporous silica was functionalized with dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride, a quaternary ammonium salt with a long hydrophobic chain, to prepare a new sorbent for the dispersive solid-phase extraction (DSPE) of seven endocrine disrupting compounds (EDCs) including 4-hexylphenol, 4-octylphenol, 4-nonylphenol, bisphenol A, estrone, 17β-estradiol and estriol in water. A series of differently functionalized MCM-48 materials were also synthesized, and they served as reference materials to study the mechanism. The developed DSPE method was combined with HPLC with fluorescence detection to evaluate the adsorption performance. The results indicated that the quaternary ammonium-functionalized MCM-48 mesoporous silica can be used as ideal sorbent for EDCs in water with recoveries of higher than 95% due to the electrostatic interactions and hydrophobic effect. Hydrogen bonding and π-π interactions in other synthesized materials could lead to about 25-30% increase in recoveries, but the results for polyhydroxy compounds were still not satisfying. The quaternary ammonium-functionalized MCM-48 mesoporous silica was successfully applied to the DSPE of EDCs in real water samples. The optimum extraction conditions were sorbent amount, 15 mg; desorption time; 5 min; elution volume, 0.8 mL; sample pH 3.0; and salt addition, 5 g/L. The limits of detection were in the range of 1.2-2.6 ng/L, while the limits of quantitation were in the range of 4.3-8.3 ng/L. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. Short-term environmental enrichment exposure induces proliferation and maturation of doublecortin-positive cells in the prefrontal cortex

    Science.gov (United States)

    Fan, Chunling; Zhang, Mengqi; Shang, Lei; Cynthia, Ngobe Akume; Li, Zhi; Yang, Zhenyu; Chen, Dan; Huang, Jufang; Xiong, Kun

    2014-01-01

    Previous studies have demonstrated that doublecortin-positive immature neurons exist predominantly in the superficial layer of the cerebral cortex of adult mammals such as guinea pigs, and these neurons exhibit very weak properties of self-proliferation during adulthood under physiological conditions. To verify whether environmental enrichment has an impact on the proliferation and maturation of these immature neurons in the prefrontal cortex of adult guinea pigs, healthy adult guinea pigs were subjected to short-term environmental enrichment. Animals were allowed to play with various cognitive and physical stimulating objects over a period of 2 weeks, twice per day, for 60 minutes each. Immunofluorescence staining results indicated that the number of doublecortin-positive cells in layer II of the prefrontal cortex was significantly increased after short-term environmental enrichment exposure. In addition, these doublecortin-positive cells co-expressed 5-bromo-2-deoxyuridine (a marker of cell proliferation), c-Fos (a marker of cell viability) and NeuN (a marker of mature neurons). Experimental findings showed that short-term environmental enrichment can induce proliferation, activation and maturation of doublecortin-positive cells in layer II of the prefrontal cortex of adult guinea pigs. PMID:25206818

  11. Cdc6 is a rate-limiting factor for proliferative capacity during HL60 cell differentiation

    International Nuclear Information System (INIS)

    Barkley, Laura R.; Hong, Hye Kyung; Kingsbury, Sarah R.; James, Michelle; Stoeber, Kai; Williams, Gareth H.

    2007-01-01

    The DNA replication (or origin) licensing pathway represents a critical step in cell proliferation control downstream of growth signalling pathways. Repression of origin licensing through down-regulation of the MCM licensing factors (Mcm2-7) is emerging as a ubiquitous route for lowering proliferative capacity as metazoan cells exit the cell division cycle into quiescent, terminally differentiated and senescent 'out-of-cycle' states. Using the HL60 monocyte/macrophage differentiation model system and a cell-free DNA replication assay, we have undertaken direct biochemical investigations of the coupling of origin licensing to the differentiation process. Our data show that down-regulation of the MCM loading factor Cdc6 acts as a molecular switch that triggers loss of proliferative capacity during early engagement of the somatic differentiation programme. Consequently, addition of recombinant Cdc6 protein to in vitro replication reactions restores DNA replication competence in nuclei prepared from differentiating cells. Differentiating HL60 cells over-expressing either wild-type Cdc6 or a CDK phosphorylation-resistant Cdc6 mutant protein (Cdc6A4) exhibit an extended period of cell proliferation compared to mock-infected cells. Notably, differentiating HL60 cells over-expressing the Cdc6A4 mutant fail to down-regulate Cdc6 protein levels, suggesting that CDK phosphorylation of Cdc6 is linked to its down-regulation during differentiation and the concomitant decrease in cell proliferation. In this experimental model, Cdc6 therefore plays a key role in the sequential molecular events leading to repression of origin licensing and loss of proliferative capacity during execution of the differentiation programme

  12. Uniform Surface Modification of 3D Bioglass®-Based Scaffolds with Mesoporous Silica Particles (MCM-41) for Enhancing Drug Delivery Capability

    Science.gov (United States)

    Boccardi, Elena; Philippart, Anahí; Juhasz-Bortuzzo, Judith A.; Beltrán, Ana M.; Novajra, Giorgia; Vitale-Brovarone, Chiara; Spiecker, Erdmann; Boccaccini, Aldo R.

    2015-01-01

    The design and characterization of a new family of multifunctional scaffolds based on bioactive glass (BG) of 45S5 composition for bone tissue engineering and drug delivery applications are presented. These BG-based scaffolds are developed via a replication method of polyurethane packaging foam. In order to increase the therapeutic functionality, the scaffolds were coated with mesoporous silica particles (MCM-41), which act as an in situ drug delivery system. These sub-micron spheres are characterized by large surface area and pore volume with a narrow pore diameter distribution. The solution used for the synthesis of the silica mesoporous particles was designed to obtain a high-ordered mesoporous structure and spherical shape – both are key factors for achieving the desired controlled drug release. The MCM-41 particles were synthesized directly inside the BG-based scaffolds, and the drug-release capability of this combined system was evaluated. Moreover, the effect of MCM-41 particle coating on the bioactivity of the BG-based scaffolds was assessed. The results indicate that it is possible to obtain a multifunctional scaffold system characterized by high and interconnected porosity, high bioactivity, and sustained drug delivery capability. PMID:26594642

  13. Effects of composite films of silk fibroin and graphene oxide on the proliferation, cell viability and mesenchymal phenotype of periodontal ligament stem cells.

    Science.gov (United States)

    Rodríguez-Lozano, F J; García-Bernal, D; Aznar-Cervantes, S; Ros-Roca, M A; Algueró, M C; Atucha, N M; Lozano-García, A A; Moraleda, J M; Cenis, J L

    2014-12-01

    In regenerative dentistry, stem cell-based therapy often requires a scaffold to deliver cells and/or growth factors to the injured site. Graphene oxide (GO) and silk fibroin (SF) are promising biomaterials for tissue engineering as they are both non toxic and promote cell proliferation. On the other hand, periodontal ligament stem cells (PDLSCs) are mesenchymal stem cells readily accessible with a promising use in cell therapy. The purpose of this study was to investigate the effects of composite films of GO, SF and GO combined with fibroin in the mesenchymal phenotype, viability, adhesion and proliferation rate of PDLSCs. PDLSCs obtained from healthy extracted teeth were cultured on GO, SF or combination of GO and SF films up to 10 days. Adhesion level of PDSCs on the different biomaterials were evaluated after 12 h of culture, whereas proliferation rate of cells was assessed using the MTT assay. Level of apoptosis was determined using Annexin-V and 7-AAD and mesenchymal markers expression of PDLSCs were analyzed by flow cytometry. At day 7 of culture, MTT experiments showed a high rate of proliferation of PDLSCs growing on GO films compared to the other tested biomaterials, although it was slightly lower than in plastic (control). However PDLSCs growing in fibroin or GO plus fibroin films showed a discrete proliferation. Importantly, at day 10 of culture it was observed a significant increase in PDLSCs proliferation rate in GO films compared to plastic (P < 0.05), as well as in GO plus fibroin compared to fibroin alone (P < 0.001). Flow cytometry analysis showed that culture of PDLSCs in fibroin, GO or GO plus fibroin films did not significantly alter the level of expression of the mesenchymal markers CD73, CD90 or CD105 up to 168 h, being the cell viability in GO even better than obtained in plastic. Our findings suggest that the combination of human dental stem cells/fibroin/GO based-bioengineered constructs have strong potential for their therapeutic

  14. Titanium phosphate glass microcarriers induce enhanced osteogenic cell proliferation and human mesenchymal stem cell protein expression

    Directory of Open Access Journals (Sweden)

    Nilay J Lakhkar

    2015-11-01

    Full Text Available In this study, we have developed 50- to 100-µm-sized titanium phosphate glass microcarriers (denoted as Ti5 that show enhanced proliferation of human mesenchymal stem cells and MG63 osteosarcoma cells, as well as enhanced human mesenchymal stem cell expression of bone differentiation markers, in comparison with commercially available glass microspheres at all time points. We also demonstrate that these microcarriers provide superior human mesenchymal stem cell proliferation with conventional Dulbecco’s Modified Eagle medium than with a specially developed commercial stem cell medium. The microcarrier proliferative capacity is revealed by a 24-fold increase in MG63 cell numbers in spinner flask bioreactor studies performed over a 7-day period, versus only a 6-fold increase in control microspheres under the same conditions; the corresponding values of Ti5 and control microspheres under static culture are 8-fold and 7-fold, respectively. The capability of guided osteogenic differentiation is confirmed by ELISAs for bone morphogenetic protein-2 and osteopontin, which reveal significantly greater expression of these markers, especially osteopontin, by human mesenchymal stem cells on the Ti5 microspheres than on the control. Scanning electron microscopy and confocal laser scanning microscopy images reveal favorable MG63 and human mesenchymal stem cell adhesion on the Ti5 microsphere surfaces. Thus, the results demonstrate the suitability of the developed microspheres for use as microcarriers in bone tissue engineering applications.

  15. Removal of Cr(VI from Aqueous Solutions Using mino-fuctionalized Nanoporous MCM-41

    Directory of Open Access Journals (Sweden)

    Farshid Ghorbani

    2016-09-01

    Full Text Available An amino-functionalized nanoporous material was prepared by grafting 3-aminopropyl trimethoxysilane (APTMS group onto MCM-41. The as-synthesized material was characterized by X-ray diffraction (XRD analysis, nitrogen adsorption-desorption measurements (BET, thermogravimetric analysis (TGA, and Fourier transform infrared spectrometry (FTIR to confirm the ordered mesoporous structure and the functionalization of the amino group. The NH2-MCM-41 thus obtained was employed as the sorbent to remove Cr(VI ions from aqueous solutions. The batch adsorption process was carried out to evaluate the effects of solution pH, adsorbent dosage, metal ion concentration, and temperature. Results revealed that removal efficiency increased to a maximum of 124 mg.g‒1 and metal uptake decreased (0.1 g.l‒1 with increasing sorbent dosage from 0.1 to 3.5 g.l‒1. A reverse trend was, however, observed with increasing Cr(VI concentration. It was also found that a pH equal to 3 was the optimum level for the removal of Cr(VI ions from aqueous solutions. Thermodynamic examinations revealed the strong dependence of the adsorption process on temperature such that adsorption capacity increased with increasing temperature, indicating the endothermic and spontaneous nature of the adsorption process.

  16. Bufalin inhibits the differentiation and proliferation of human osteosarcoma cell line hMG63-derived cancer stem cells.

    Science.gov (United States)

    Chang, Yuewen; Zhao, Yongfang; Zhan, Hongsheng; Wei, Xiaoen; Liu, Tianjin; Zheng, Bo

    2014-02-01

    Cancer stem cells (CSCs) play an important role in drug resistance of tumor and are responsible for high recurrence rates. Agents that can suppress the proliferation and differentiation of CSCs would provide new opportunity to fight against tumor recurrence. In this study, we developed a new strategy to enrich CSCs in human osteosarcoma cell line hMG63. Using these CSCs as model, we tested the effect of bufalin, a traditional Chinese medicine, on the proliferation and differentiation of CSCs. hMG63 cells were cultured in poly-HEMA-treated dish and cancer stem cell-specific medium. In this nonadhesive culture system, hMG63 formed spheres, which were then collected and injected into the immunodeficient mice. Cisplatin was administered every 3 days for five times. The enriched xenograft tumors were cultured in cancer stem cell-specific medium again to form tumor spheres. Expression of cancer stem cell markers of these cells was measured by flow cytometry. These cells were then treated with bufalin, and the proliferation and differentiation ability were indicated by the expression level of molecular markers and the formation of sphere again in vitro. We obtained a low CD133+/CD44 cell population with high-level stem cell marker. When treated with bufalin, the sphere could not get attached to the flask and failed to differentiate, which was indicated by the stable expression of stem cell marker CD133 and OCT-4 in the condition permissive to differentiation. Treatment of bufalin also suppressed the single cells isolated from the sphere to form sphere again in the nonadhesive culture system, and a decreased expression of proliferation marker Ki67 was also detected in these cells. Sphere-formed and chemoresistant colon xenograft tumors in immunodeficient mice could enrich cancer stem cell population. Bufalin could inhibit proliferation and differentiation of CSCs.

  17. CCL19/CCR7 contributes to the pathogenesis of endometriosis via PI3K/Akt pathway by regulating the proliferation and invasion of ESCs.

    Science.gov (United States)

    Diao, Ruiying; Wei, Weixia; Zhao, Jinghui; Tian, Fuying; Cai, Xueyong; Duan, Yong-Gang

    2017-11-01

    The level of CCL19 increased in the peritoneal fluid of women with endometriosis, but the precise mechanism of CCL19/CCR7 in the pathogenesis of endometriosis remains unknown. ELISA and immunohistochemistry were performed to analyze CCL19/CCR7 expressions in peritoneal fluid and endometrium from women with endometriosis (n = 38) and controls (n = 32). Cell proliferation and transwell invasion assays were applied to detect proliferation and invasion of human endometrial stromal cells (ESCs). Expressions of Bcl2, MMP2, MMP9, and p-AKT/AKT were analyzed by Western blot. Peritoneal fluid concentration of CCL19 in patients with endometriosis was higher than that in controls. Those patients with moderate/severe endometriosis had significantly higher peritoneal fluid concentrations of CCL19 compared to those with minimal/mild endometriosis. Higher CCL19 and CCR7 were found in the endometrium with endometriosis compared to control. CCL19 significantly enhanced ESC proliferation and invasion through CCR7 via activating PI3K/Akt signal pathways. CCL19/CCR7 interaction significantly enhanced phosphorylation of Akt, Bcl2, MMP2, and MMP9 in ESCs. These data indicate CCL19/CCR7 contributes to proliferation and invasion of ESCs, which are conducive to the pathogenesis of endometriosis through activating PI3K/Akt pathway. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. Catalytic properties and acidity of modified MCM-41 mesoporous materials with low Si/Al ratio: heptane isomerisation

    Directory of Open Access Journals (Sweden)

    Ahmed Belhakem

    2006-06-01

    Full Text Available The catalytic properties and acidity of modified MCM-41 with a low Si/Al ratio and 0-95% NH4+ exchange were investigated. The samples were characterised by X-ray diffraction, scanning and transmission electron microscopy, and nitrogen adsorption. The acidity was studied by pyridine adsorption, temperature programmed desorption (TPD of ammonia, and infrared (IR spectroscopy. Adsorption of pyridine and IR spectroscopy indicated various types of Lewis and Brönsted acid sites. The density distribution of acid sites was determined by TPD. Both Lewis and Brönsted acid sites were found to be active in the heptane isomerisation. The presence of aluminium (low Si/Al combined to the ionic exchange between Na+ and NH4+ increases the acidity of MCM-41 materials. A close correlation between acidity and isomerisation was observed. Coke deposition, which reduces the activity, was also studied.

  19. PKI-587 and sorafenib alone and in combination on inhibition of liver cancer stem cell proliferation.

    Science.gov (United States)

    Gedaly, Roberto; Galuppo, Roberto; Musgrave, Yolanda; Angulo, Paul; Hundley, Jonathan; Shah, Malay; Daily, Michael F; Chen, Changguo; Cohen, Donald A; Spear, Brett T; Evers, B Mark

    2013-11-01

    Deregulated Ras/Raf/mitogen-activated protein kinase and PI3 K/AKT/mTOR signaling pathways are significant in hepatocellular carcinoma proliferation (HCC). In this study we evaluated differences in the antiproliferative effect of dual PI3 K/Akt/mTOR and Ras/Raf/mitogen-activated protein kinase inhibition of non liver cancer stem cell lines (PLC and HuH7) and liver cancer stem cell (LCSC) lines (CD133, CD44, CD24, and aldehyde dehydrogenase 1-positive cells). Flow cytometry was performed on the resulting tumors to identify the LCSC markers CD133, CD44, CD24, and aldehyde dehydrogenase 1. Methylthiazol tetrazolium assay was used to assess cellular proliferation. Finally, a Western blot assay was used to evaluate for inhibition of specific enzymes in these two signaling pathways. Using flow cytometry, we found that LCSC contain 64.4% CD133 + cells, 83.2% CD44 + cells, and 96.4% CD24 + cells. PKI-587 and sorafenib caused inhibiton of LCSC and HCC cell proliferation. PLC cells were more sensitive to PKI-587 than LCSC or Huh7 (P PKI-587 and sorafenib caused significantly more inhibition than monotherapy in HuH7, PLC, and LCSC. Using the methylthiazol tetrazolium assay, we found that the LCSC proliferation was inhibited with sorafenib monotherapy 39% at 5 μM (P PKI-587 at 0.1 μM (P = 0.002, n = 12) compared with control. The combination of PKI-587 and sorafenib, however, synergistically inhibited LCSC proliferation by 86% (P = 0.002; n = 12). LCSC (CD133+, CD44+, CD24+) were able to develop very aggressive tumors with low cell concentrations at 4 to 6 wk. Cells CD133+, CD44+, CD24+, which demonstrated at least moderate resistance to therapy in vitro. The combination of PKI-587 and sorafenib was better than either drug alone at inhibiting of LCSC and on HCC cell proliferation. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. CCL5 promotes proliferation of MCF-7 cells through mTOR-dependent mRNA translation

    International Nuclear Information System (INIS)

    Murooka, Thomas T.; Rahbar, Ramtin; Fish, Eleanor N.

    2009-01-01

    The proliferative capacity of cancer cells is regulated by factors intrinsic to cancer cells and by secreted factors in the microenvironment. Here, we investigated the proto-oncogenic potential of the chemokine receptor, CCR5, in MCF-7 breast cancer cell lines. At physiological levels, CCL5, a ligand for CCR5, enhanced MCF-7.CCR5 proliferation. Treatment with the mTOR inhibitor, rapamycin, inhibited this CCL5-inducible proliferation. Because mTOR directly modulates mRNA translation, we investigated whether CCL5 activation of CCR5 leads to increased translation. CCL5 induced the formation of the eIF4F translation initiation complex through an mTOR-dependent process. Indeed, CCL5 initiated mRNA translation, shown by an increase in high-molecular-weight polysomes. Specifically, we show that CCL5 mediated a rapid up-regulation of protein expression for cyclin D1, c-Myc and Dad-1, without affecting their mRNA levels. Taken together, we describe a mechanism by which CCL5 influences translation of rapamycin-sensitive mRNAs, thereby providing CCR5-positive breast cancer cells with a proliferative advantage.

  1. Cascade synthesis of dihydrobenzofuran via Claisen rearrangement of allyl aryl ethers using FeCl3/MCM-41 catalyst

    Directory of Open Access Journals (Sweden)

    Sachin S. Sakate

    2018-05-01

    Full Text Available Dihydrobenzofuran as one of the active ingredients of the naturally occurring motif is synthesized by using in situ generation of ortho allyl phenols. Aryl allyl ethers on reacting with catalytic amounts of non noble metal iron (III chloride supported on MCM-41 under moderate reaction conditions yield dihydrobenzofuran. First step via Claisen rearrangement gives ortho allyl phenol followed by its in situ cyclization to yield dihydrobenzofuran in very good yields. Both Lewis as well as Brønsted acidity of the catalyst as evidenced by Py-FTIR studies was found to catalyze the cascade synthesis of dihydrobenzofuran. The scope of the present strategy was successfully demonstrated for several substrates with varying electronic effects for the synthesis of corresponding dihydrobenzofuran with high yields in a range of 71–86%. Keywords: Claisen rearrangement, Dihydrobenzofuran, Aryl allyl ether, MCM-41, Ferric chloride

  2. LncRNA Taurine-Upregulated Gene 1 Promotes Cell Proliferation by Inhibiting MicroRNA-9 in MCF-7 Cells.

    Science.gov (United States)

    Zhao, Xiao-Bo; Ren, Guo-Sheng

    2016-12-01

    This study was designed to investigate the role of taurine-upregulated gene 1 ( TUG1 ) in MCF-7 breast cancer cells and the molecular mechanism involved in the regulation of microRNA-9 (miR-9). The expression of TUG1 in breast cancer tissues and cells was evaluated using quantitative reverse transcription polymerase chain reaction. Cell viability was examined using a 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay; cell cycle progression and apoptosis were analyzed using flow cytometry. A dual luciferase reporter assay was used to detect the relationship between TUG1 and miR-9. The expression of methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) was measured by western blot. Higher expression of TUG1 was observed in breast cancer tissues and cell lines than in the corresponding controls. TUG1 knockdown reduced proliferation, suppressed cell cycle progression, and promoted apoptosis of MCF-7 cells. The dual luciferase reporter assay showed that TUG1 could negatively regulate the expression of miR-9. MiR-9 inhibition abrogated the effect of TUG1 knockdown on the proliferation, cell cycle progression, and apoptosis of MCF-7 cells. TUG1 positively regulated the expression of MTHFD2 in breast cancer cells. TUG1 knockdown was significantly associated with decreased cell proliferation and it promoted apoptosis of breast cancer cells through the regulation of miR-9.

  3. Alternating current electric fields of varying frequencies: effects on proliferation and differentiation of porcine neural progenitor cells.

    Science.gov (United States)

    Lim, Ji-Hey; McCullen, Seth D; Piedrahita, Jorge A; Loboa, Elizabeth G; Olby, Natasha J

    2013-10-01

    Application of sinusoidal electric fields (EFs) has been observed to affect cellular processes, including alignment, proliferation, and differentiation. In the present study, we applied low-frequency alternating current (AC) EFs to porcine neural progenitor cells (pNPCs) and investigated the effects on cell patterning, proliferation, and differentiation. pNPCs were grown directly on interdigitated electrodes (IDEs) localizing the EFs to a region accessible visually for fluorescence-based assays. Cultures of pNPCs were exposed to EFs (1 V/cm) of 1 Hz, 10 Hz, and 50 Hz for 3, 7, and 14 days and compared to control cultures. Immunocytochemistry was performed to evaluate the expression of neural markers. pNPCs grew uniformly with no evidence of alignment to the EFs and no change in cell numbers when compared with controls. Nestin expression was shown in all groups at 3 and 7 days, but not at 14 days. NG2 expression was low in all groups. Co-expression of glial fibrillary acidic protein (GFAP) and TUJ1 was significantly higher in the cultures exposed to 10- and 50-Hz EFs than the controls. In summary, sinusoidal AC EFs via IDEs did not alter the alignment and proliferation of pNPCs, but higher frequency stimulation appeared to delay differentiation into mature astrocytes.

  4. A comparison of the effects of tributyltin chloride and triphenyltin chloride on cell proliferation, proapoptotic p53, Bax, and antiapoptotic Bcl-2 protein levels in human breast cancer MCF-7 cell line.

    Science.gov (United States)

    Fickova, Maria; Macho, Ladislav; Brtko, Julius

    2015-06-01

    In recent years it was disclosed, that numerous organotin(IV) derivatives have remarkable cytotoxicity against several types of cancer cells. The property to inhibit cell growth makes these compounds promising for antitumor therapy, as the clinical effectiveness of cisplatin is limited by drug resistance and significant side effects. Tributyltin and triphenyltin are known as endocrine disruptors. Moreover, the compounds exert their toxicity in mammals predominantly through nuclear receptor signaling. Here we present the effects of tributyltin chloride (TBT-Cl) and triphenyltin chloride (TPT-Cl) on cell proliferation, expression of proapoptotic p53, Bax, and antiapoptotic Bcl-2 proteins in human breast cancer MCF-7 cell line. Dose and time dependent (24, 48 and 72 h) cell expositions have demonstrated TBT-Cl as more effective in inhibiting MCF-7 cell proliferation than TPT-Cl. Short time treatment with TBT-Cl displayed marked stimulation of p53 protein expression when compared to TPT-Cl. Both organotin compounds displayed similar mild enhancement of Bax protein expression. The 24h exposition of TPT-Cl induced substantial diminution of Bcl-2 protein expression in comparison with both, untreated cells and TBT-Cl treated cells. Our observations indicate that TBT-Cl and TPT-Cl have different antiproliferative potency and distinct impact on expression of apoptosis marker proteins. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. ERK/CANP rapid signaling mediates 17β-estradiol-induced proliferation of human breast cancer cell line MCF-7 cells.

    Science.gov (United States)

    Wang, Guo-Sheng; Huang, Yan-Gang; Li, Huan; Bi, Shi-Jie; Zhao, Jin-Long

    2014-01-01

    17β-estradiol (E2) exerts its functions through both genomic and non-genomic signaling pathways. Because E2 is important in breast cancer development, we investigated whether its actions in promoting breast cancer cell proliferation occur through the non-genomic signaling pathway via extracellular signal-regulated kinase 1/2 (ERK1/2)/calcium-activated neutral protease (CANP). MCF-7 breast cancer cells were treated with ERKl/2 inhibitor (PD98059) or CANP inhibitor (calpeptin) before exposure to 1×10(-8) M E2. MTT colorimetry and flow cytometry were used to analyze effects on cell proliferation and cell cycle progression, respectively. Expression of phosphorylated-ERK (p-ERK), total ERK, and Capn4 proteins were assessed by Western blotting. Cell proliferation increased in cells treated with E2 for 24 h (P<0.05), and the proportion of cells in G0/G1 was decreased, accompanied by accelerated G1/S. Calpeptin pre-treatment significantly inhibited the E2-induced proliferation of MCF-7 cells (P<0.05), while also ameliorating the effects of E2 on cell cycle progression. Further, expression of p-ERK was rapidly up-regulated (after 10 min) by E2 (P<0.05), an effect that persisted 16 h after E2 exposure but which was significantly inhibited by PD98059 (P<0.05). Finally, expression of Capn4 protein was rapidly up-regulated in E2-exposed cells (P<0.05), but this change was significantly inhibited by PD98059 or calpeptin (P<0.05) pre-treatment. Thus, the rapid, non-genomic ERK/CANP signaling pathway mediates E2-induced proliferation of human breast cancer cells.

  6. Dedifferentiation, Proliferation, and Redifferentiation of Adult Mammalian Cardiomyocytes After Ischemic Injury.

    Science.gov (United States)

    Wang, Wei Eric; Li, Liangpeng; Xia, Xuewei; Fu, Wenbin; Liao, Qiao; Lan, Cong; Yang, Dezhong; Chen, Hongmei; Yue, Rongchuan; Zeng, Cindy; Zhou, Lin; Zhou, Bin; Duan, Dayue Darrel; Chen, Xiongwen; Houser, Steven R; Zeng, Chunyu

    2017-08-29

    Adult mammalian hearts have a limited ability to generate new cardiomyocytes. Proliferation of existing adult cardiomyocytes (ACMs) is a potential source of new cardiomyocytes. Understanding the fundamental biology of ACM proliferation could be of great clinical significance for treating myocardial infarction (MI). We aim to understand the process and regulation of ACM proliferation and its role in new cardiomyocyte formation of post-MI mouse hearts. β-Actin-green fluorescent protein transgenic mice and fate-mapping Myh6-MerCreMer-tdTomato/lacZ mice were used to trace the fate of ACMs. In a coculture system with neonatal rat ventricular myocytes, ACM proliferation was documented with clear evidence of cytokinesis observed with time-lapse imaging. Cardiomyocyte proliferation in the adult mouse post-MI heart was detected by cell cycle markers and 5-ethynyl-2-deoxyuridine incorporation analysis. Echocardiography was used to measure cardiac function, and histology was performed to determine infarction size. In vitro, mononucleated and bi/multinucleated ACMs were able to proliferate at a similar rate (7.0%) in the coculture. Dedifferentiation proceeded ACM proliferation, which was followed by redifferentiation. Redifferentiation was essential to endow the daughter cells with cardiomyocyte contractile function. Intercellular propagation of Ca 2+ from contracting neonatal rat ventricular myocytes into ACM daughter cells was required to activate the Ca 2+ -dependent calcineurin-nuclear factor of activated T-cell signaling pathway to induce ACM redifferentiation. The properties of neonatal rat ventricular myocyte Ca 2+ transients influenced the rate of ACM redifferentiation. Hypoxia impaired the function of gap junctions by dephosphorylating its component protein connexin 43, the major mediator of intercellular Ca 2+ propagation between cardiomyocytes, thereby impairing ACM redifferentiation. In vivo, ACM proliferation was found primarily in the MI border zone. An ischemia

  7. Zeolite MCM-22 Modified with Au and Cu for Catalytic Total Oxidation of Methanol and Carbon Monoxide

    Czech Academy of Sciences Publication Activity Database

    Kaminski, P.; Sobczak, I.; Decyk, P.; Ziolek, M.; Roth, Wieslaw Jerzy; Campo, B.; Daturi, M.

    2013-01-01

    Roč. 117, č. 5 (2013), s. 2147-2159 ISSN 1932-7447 R&D Projects: GA ČR(CZ) GAP106/12/0189 Institutional support: RVO:61388955 Keywords : adsorption * carbon dioxide * MCM-22 zeolites Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.835, year: 2013

  8. Oxidative Stress Induces Senescence in Cultured RPE Cells.

    Science.gov (United States)

    Aryan, Nona; Betts-Obregon, Brandi S; Perry, George; Tsin, Andrew T

    2016-01-01

    The aim of this research is to determine whether oxidative stress induces cellular senescence in human retinal pigment epithelial cells. Cultured ARPE19 cells were subjected to different concentrations of hydrogen peroxide to induce oxidative stress. Cells were seeded into 24-well plates with hydrogen peroxide added to cell medium and incubated at 37°C + 5% CO2 for a 90-minute period [at 0, 300, 400 and 800 micromolar (MCM) hydrogen peroxide]. The number of viable ARPE19 cells were recorded using the Trypan Blue Dye Exclusion Method and cell senescence was measured by positive staining for senescence-associated beta-galactosidase (SA-beta-Gal) protein. Without hydrogen peroxide treatment, the number of viable ARPE19 cells increased significantly from 50,000 cells/well to 197,000 within 72 hours. Treatment with hydrogen peroxide reduced this level of cell proliferation significantly (to 52,167 cells at 400 MCM; to 49,263 cells at 800 MCM). Meanwhile, cells with a high level of positive senescence-indicator SA-Beta-Gal-positive staining was induced by hydrogen peroxide treatment (from a baseline level of 12% to 80% at 400 MCM and at 800 MCM). Our data suggests that oxidative stress from hydrogen peroxide treatment inhibited ARPE19 cell proliferation and induced cellular senescence.

  9. Fabrication of a high-density MCM-D for a pixel detector system using a BCB/Cu technology

    CERN Document Server

    Topper, M; Engelmann, G; Fehlberg, S; Gerlach, P; Wolf, J; Ehrmann, O; Becks, K H; Reichl, H

    1999-01-01

    The MCM-D which is described here is a prototype for a pixel detector system for the planned Large Hadron Collider (LHC) at CERN, Geneva. The project is within the ATLAS experiment. The module consists of a sensor tile with an active area of 16.4 mm*60.4 mm, 16 readout chips, each serving 24*160 pixel unit cells, a module controller chip, an optical transceiver and the local signal interconnection and power distribution buses. The extremely high wiring density which is necessary to interconnect the readout chips was achieved using a thin film copper/photo-BCB process above the pixel array. The bumping of the readout chips was done by PbSn electroplating. All dice are then attached by flip-chip assembly to the sensor diodes and the local buses. The focus of this paper is a detailed description of the technologies for the fabrication of this advanced MCM-D. (10 refs).

  10. The proliferation marker pKi-67 organizes the nucleolus during the cell cycle depending on Ran and cyclin B.

    Science.gov (United States)

    Schmidt, Mirko H H; Broll, Rainer; Bruch, Hans-Peter; Bögler, Oliver; Duchrow, Michael

    2003-01-01

    The proliferation marker pKi-67 ('Ki-67 antigen') is commonly used in clinical and research pathology to detect proliferating cells, as it is only expressed during cell-cycle progression. Despite the fact that this antigen has been known for nearly two decades, there is still no adequate understanding of its function. This study has therefore identified proteins that interact with pKi-67, using a yeast two-hybrid system. A mammalian two-hybrid system and immunoprecipitation studies were used to verify these interactions. Among other cell-cycle regulatory proteins, two binding partners associated with the small GTPase Ran were identified. In addition, DNA-structural and nucleolus-associated proteins binding to pKi-67 were found. Moreover, it was demonstrated that the N-terminal domain of pKi-67 is capable of self-binding to its own repeat region encoded by exon 13. Since RanBP, a protein involved in the transport of macromolecules over the nuclear lamina, was found to be a binding partner, a possible effect of pKi-67 on the localization of cell-cycle regulatory proteins was proposed. To test this hypothesis, a tetracycline-responsive gene expression system was used to induce the pKi-67 fragments previously used for the two-hybrid screens in HeLa cells. Subsequent immunostaining revealed the translocation of cyclin B1 from cytoplasm to nucleoli in response to this expression. It is suggested that pKi-67 is a Ran-associated protein with a role in the disintegration and reformation of the nucleolus and thereby in entry into and exit from the M-phase. Copyright 2002 John Wiley & Sons, Ltd.

  11. Immunohistochemical proliferation markers may overestimate the growth potential after ionizing radiation. In vivo study in the rat anterior pituitary gland

    International Nuclear Information System (INIS)

    Nakasu, Satoshi; Fukami, Tadateru; Matsuda, Masayuki; Nakasu, Yoko

    2003-01-01

    The effect of ionizing radiation on the expression of immunohistochemical proliferation markers was examined in the rat pituitary gland. Rats were irradiated in the pituitary region with a dose of 40 Gy, or were sham-irradiated as controls. Bromodeoxyuridine (BrdU) was given to the rats after one week, either one hour (Br-1 group) or 17 hours (Br-17 group) before perfusion fixation. Immunohistochemical staining for BrdU, topoisomerase II-alpha (TopoII), Ki-67 (MIB-5), p21 WAF1/CiP1 (p21), and p27 Kip1 (p27) was performed. Apoptotic cells were detected by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end-labeling method. The mean BrdU labeling index (LI) and MIB-5 LI were significantly higher in the irradiated rats than in the sham rats in the Br-1 group. TopoII LI was higher in the irradiated rats than in the sham rats, although not significantly. p27-positive cells decreased in irradiated rats, but p21-positive cells increased more than in the sham rats. The number of apoptotic cells increased significantly after radiation. BrdU LIs were lower in the irradiated rats than in the sham rats in the Br-17 group. A few small BrdU-positive fragments with apoptotic features were phagocytosed in the anterior lobe cells. These results indicate that some ''immunohistochemically proliferating cells'' subsequently undergo apoptosis in the irradiated pituitary gland. The values of proliferative indices should be cautiously interpreted after irradiation of tissue. (author)

  12. Bizarre parosteal osteochondromatous proliferation: a new cytogenetic subgroup characterized by inversion of chromosome 7.

    Science.gov (United States)

    Broehm, Cory J; M'Lady, Gary; Bocklage, Thèrése; Wenceslao, Stella; Chafey, David

    2013-11-01

    Bizarre parosteal osteochondromatous proliferation (BPOP) is a rare, benign osteocartilaginous lesion characterized by a mixture of immature bone, bland spindle cells, and irregular, hypercellular cartilage undergoing calcification. A t(1;17)(q32;q21) has been reported as a unique recurring translocation identified in seven cases. Inversion of chromosome 7, inv(7)(q22q32), has also recently been described in one case of BPOP. We report an additional case of inv(7) in a BPOP occurring on the distal radius in a 36-year-old woman who presented with a slow-growing mass on the right wrist. Metaphase karyotype analysis of fresh tissue from tumor taken at resection revealed an inv(7)(q22q32). A review of the literature identified two additional cases of inv(7) (q21.1q31.3 and q22.1q31.3), both paired with inv(6)(p25q15), bringing the total number of cases of inv(7) in BPOP to four. These data suggest inv(7) may be another characteristic cytogenetic abnormality associated with and possibly contributing to the development of BPOP. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Density profile of nitrogen in cylindrical pores of MCM-41

    Science.gov (United States)

    Soper, Alan K.; Bowron, Daniel T.

    2017-09-01

    A straightforward approach using radiation scattering (X-ray or neutron) combined with atomistic modelling is used to accurately assess the pore dimensions in the porous silica, MCM-41. The method is used to calculate the density profile of nitrogen absorbed in this material at a variety of fractional pressures, p/p0, where p0 is the saturated vapour pressure, up to p/p0 = 0.36 at T = 87 K in the present instance. At this pressure two distinct layers of liquid nitrogen occur on the silica surface, with a relatively sharp gas-liquid interface. It is suggested surface tension effects at this interface strongly influence the growth of further layers.

  14. Kinetics of propane dehydrogenation in CO{sub 2} presence over chromium and gallium oxide catalysts based on MCM-41

    Energy Technology Data Exchange (ETDEWEB)

    Lapidus, A.L.; Gaidai, N.A.; Nekrasov, N.V.; Agafonov, A.Yu.; Botavina, M.A. [Russian Academy of Sciences, Moscow (Russian Federation). N.D. Zelinsky Institute of Organic Chemistry

    2012-07-01

    Chromium and gallium catalysts based on MCM-41 with different contents of active metals were prepared and tested for propane dehydrogenation in the presence and absence of CO{sub 2}. It was shown that CO{sub 2} increased the yield of propene and decreased considerably the rate of deactivation of Cr/MCM-41 and decreased propene yield and slightly improved the stability of Ga/MCM-41. The study of kinetics in unstationary and stationary fields showed that the decrease of propene yield was connected with strong competitive adsorption of CO{sub 2} over Ga-catalysts what presented difficulties for propane adsorption. The formation of cracking products was decreased in CO{sub 2} presence over both catalysts. The catalysts were differed by the adsorption capacity of the reaction components: C{sub 3}H{sub 6} was tied more strongly than CO{sub 2} over Cr-catalysts, CO{sub 2} was tied more firmly than C{sub 3}H{sub 6} over Ga-catalysts. Kinetic data showed that of H{sub 2} was bounded with the surface of Ga-catalysts very firmly, reverse watergas shift reaction proceeded in considerably more extent over Cr-catalysts than over Gaones. CO{sub 2} took active participation in oxidation of coke and surface of Cr-catalysts. The positive role of CO{sub 2} in propane dehydrogenation over Ga-catalysts consisted in a decrease of coke and cracking products. Kinetic equations and step-schemes for propene and cracking products formation were proposed. (orig.)

  15. Marker Assisted Transfer of Two Powdery Mildew Resistance Genes PmTb7A.1 and PmTb7A.2 from Triticum boeoticum (Boiss.) to Triticum aestivum (L.).

    Science.gov (United States)

    Elkot, Ahmed Fawzy Abdelnaby; Chhuneja, Parveen; Kaur, Satinder; Saluja, Manny; Keller, Beat; Singh, Kuldeep

    2015-01-01

    Powdery mildew (PM), caused by Blumeria graminis f. sp. tritici, is one of the important wheat diseases, worldwide. Two PM resistance genes, designated as PmTb7A.1 and PmTb7A.2, were identified in T. boeoticum acc. pau5088 and mapped on chromosome 7AL approximately 48cM apart. Two resistance gene analogue (RGA)-STS markers Ta7AL-4556232 and 7AL-4426363 were identified to be linked to the PmTb7A.1 and PmTb7A.2, at a distance of 0.6cM and 6.0cM, respectively. In the present study, following marker assisted selection (MAS), the two genes were transferred to T. aestivum using T. durum as bridging species. As many as 12,317 florets of F1 of the cross T. durum /T. boeoticum were pollinated with T. aestivum lines PBW343-IL and PBW621 to produce 61 and 65 seeds, respectively, of three-way F1. The resulting F1s of the cross T. durum/T. boeoticum//T. aestivum were screened with marker flanking both the PM resistance genes PmTb7A.1 and PmTb7A.2 (foreground selection) and the selected plants were backcrossed to generate BC1F1. Marker assisted selection was carried both in BC1F1 and the BC2F1 generations. Introgression of alien chromatin in BC2F1 plants varied from 15.4-62.9 percent. Out of more than 110 BC2F1 plants showing introgression for markers linked to the two PM resistance genes, 40 agronomically desirable plants were selected for background selection for the carrier chromosome to identify the plants with minimum of the alien introgression. Cytological analysis showed that most plants have chromosome number ranging from 40-42. The BC2F2 plants homozygous for the two genes have been identified. These will be crossed to generate lines combining both the PM resistance genes but with minimal of the alien introgression. The PM resistance gene PmTb7A.1 maps in a region very close to Sr22, a stem rust resistance gene effective against the race Ug99. Analysis of selected plants with markers linked to Sr22 showed introgression of Sr22 from T. boeoticum in several BC2F1 plants

  16. Marker Assisted Transfer of Two Powdery Mildew Resistance Genes PmTb7A.1 and PmTb7A.2 from Triticum boeoticum (Boiss. to Triticum aestivum (L..

    Directory of Open Access Journals (Sweden)

    Ahmed Fawzy Abdelnaby Elkot

    Full Text Available Powdery mildew (PM, caused by Blumeria graminis f. sp. tritici, is one of the important wheat diseases, worldwide. Two PM resistance genes, designated as PmTb7A.1 and PmTb7A.2, were identified in T. boeoticum acc. pau5088 and mapped on chromosome 7AL approximately 48cM apart. Two resistance gene analogue (RGA-STS markers Ta7AL-4556232 and 7AL-4426363 were identified to be linked to the PmTb7A.1 and PmTb7A.2, at a distance of 0.6cM and 6.0cM, respectively. In the present study, following marker assisted selection (MAS, the two genes were transferred to T. aestivum using T. durum as bridging species. As many as 12,317 florets of F1 of the cross T. durum /T. boeoticum were pollinated with T. aestivum lines PBW343-IL and PBW621 to produce 61 and 65 seeds, respectively, of three-way F1. The resulting F1s of the cross T. durum/T. boeoticum//T. aestivum were screened with marker flanking both the PM resistance genes PmTb7A.1 and PmTb7A.2 (foreground selection and the selected plants were backcrossed to generate BC1F1. Marker assisted selection was carried both in BC1F1 and the BC2F1 generations. Introgression of alien chromatin in BC2F1 plants varied from 15.4-62.9 percent. Out of more than 110 BC2F1 plants showing introgression for markers linked to the two PM resistance genes, 40 agronomically desirable plants were selected for background selection for the carrier chromosome to identify the plants with minimum of the alien introgression. Cytological analysis showed that most plants have chromosome number ranging from 40-42. The BC2F2 plants homozygous for the two genes have been identified. These will be crossed to generate lines combining both the PM resistance genes but with minimal of the alien introgression. The PM resistance gene PmTb7A.1 maps in a region very close to Sr22, a stem rust resistance gene effective against the race Ug99. Analysis of selected plants with markers linked to Sr22 showed introgression of Sr22 from T. boeoticum in

  17. Metathesis of 2-pentene over Mo and W supported mesoporous molecular sieves MCM-41 and SBA-15

    Czech Academy of Sciences Publication Activity Database

    Ibrahim, M. A.; Akhtar, M. N.; Čejka, Jiří; Montanari, E.; Balcar, Hynek; Kubů, Martin; Al-Khattaf, S. S.

    2017-01-01

    Roč. 53, SEP 2017 (2017), s. 119-126 ISSN 1226-086X R&D Projects: GA ČR(CZ) GAP106/12/0189 Institutional support: RVO:61388955 Keywords : metathesis * MCM-41 * SBA-15 Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 4.421, year: 2016

  18. Effect of activated autologous platelet-rich plasma on proliferation and osteogenic differentiation of human adipose-derived stem cells in vitro

    Science.gov (United States)

    Xu, Fang-Tian; Li, Hong-Mian; Yin, Qing-Shui; Liang, Zhi-Jie; Huang, Min-Hong; Chi, Guang-Yi; Huang, Lu; Liu, Da-Lie; Nan, Hua

    2015-01-01

    To investigate whether activated autologous platelet-rich plasma (PRP) can promote proliferation and osteogenic differentiation of human adipose-derived stem cells (hASCs) in vitro. hASCs were isolated from lipo-aspirates, and characterized by specific cell markers and multilineage differentiation capacity after culturing to the 3rd passage. PRP was collected and activated from human peripheral blood of the same patient. Cultured hASCs were treated with normal osteogenic inductive media alone (group A, control) or osteogenic inductive media plus 5%, 10%, 20%, 40%PRP (group B, C, D, E, respectively). Cell proliferation was assessed by CCK-8 assay. mRNA expression of osteogenic marker genes including alkaline phosphatase (ALP), osteopontin (OPN), osteocalcin (OCN) and core binding factor alpha 1 (Cbfa1) were determined by Real-Time Quantitative PCR Analysis (qPCR). Data revealed that different concentrations of activated autologous PRP significantly promoted hASCs growth in the proliferation phase compared to the without PRP group and resulted in a dose-response relationship. At 7-d and 14-d time point of the osteogenic induced stage, ALP activity in PRP groups gradually increased with the increasing of concentrations of PRP and showed that dose-response relationship. At 21-d time point of the osteogenic induced stage, PRP groups make much more mineralization and mRNA relative expression of ALP, OPN, OCN and Cbfa1 than that without PRP groups and show that dose-response relationship. This study indicated that different concentrations of activated autologous PRP can promote cell proliferation at earlier stage and promote osteogenic differentiation at later stage of hASCs in vitro. Moreover, it displayed a dose-dependent effect of activated autologous PRP on cell proliferation and osteogenic differentiation of hASCs in vitro. PMID:25901195

  19. Spatiotemporal distribution of proliferation, proapoptotic and antiapoptotic factors in the early human limb development.

    Science.gov (United States)

    Bečić, Tina; Bilan, Kanito; Mardešić, Snježana; Vukojević, Katarina; Saraga-Babić, Mirna

    2016-06-01

    Involvement of proliferation and apoptosis in the human limb development was analyzed electronmicroscopically and immunohistochemically in histological sections of 8 human embryos, 4(th) -10(th) week old, using apoptotic (caspase-3, AIF, BAX), anti-apoptotic (Bcl-2) and proliferation (Ki-67) markers, and TUNEL method. The data were analyzed by Mann-Whitney test, Kruskal-Wallis and Dunn's post hoc test. Initially, developing human limbs consisted of mesenchymal core and surface ectoderm with apical ectodermal ridge (AER). During progression of development, strong proliferation activity gradually decreased in the mesenchyme (from 78% to 68%) and in the epithelium (from 62% to 42%), while in the differentiating finger cartilages proliferation was constantly low (26-7%). Apoptotic caspase-3 and AIF-positive cells characterized mesenchyme and AER at earliest stages, while during digit separation they appeared in interdigital mesenchyme as well. Strong Bcl-2 expression was observed in AER, subridge mesenchyme and phalanges, while BAX expression charaterized limb areas undergoing apoptosis. Ultrastructurally, proliferating cells showed mitotic figures, while apoptotic cells were characterized by nuclear fragmentation. Macrophages were observed around the apoptotic cells. We suggest that intense proliferation enables growth and elongation of human limb primordia, and differential growth of digits. Both caspase-3 and AIF-dependant pathways of cell death control the extent of AER and numer of cells in the subridge mesenchyme at earliest developmental stages, as well as process of digit separation at later stages of limb development. Spatio-temporal co-expresson of Bcl-2 and BAX indicates their role in suppression of apoptosis and selective stimulation of growth during human limb morphogenesis. Copyright © 2016 Elsevier GmbH. All rights reserved.

  20. Galectin-7 promotes proliferation and Th1/2 cells polarization toward Th1 in activated CD4+ T cells by inhibiting The TGFβ/Smad3 pathway.

    Science.gov (United States)

    Luo, Zhenlong; Ji, Yudong; Tian, Dean; Zhang, Yong; Chang, Sheng; Yang, Chao; Zhou, Hongmin; Chen, Zhonghua Klaus

    2018-06-08

    Galectin-7 (Gal-7) has been associated with cell proliferation and apoptosis. It is known that Gal-7 antagonises TGFβ-mediated effects in hepatocytes by interacting with Smad3. Previously, we have demonstrated that Gal-7 is related to CD4+ T cells responses; nevertheless, its effect and functional mechanism on CD4+ T cells responses remain unclear. The murine CD4+ T cells were respectively cultured with Gal-7, anti-CD3/CD28 mAbs, or with anti-CD3/CD28 mAbs & Gal-7. The effects of Gal-7 on proliferation and the phenotypic changes in CD4+ T cells were assessed by flow cytometry. The cytokines from CD4+ T cells were analysed by quantitative real-time PCR. Subcellular localisation and expression of Smad3 were determined by immunofluorescence staining and Western blot, respectively. Gal-7 enhanced the proliferation of activated CD4+ T cells in a dose- and β-galactoside-dependent manner. Additionally, Gal-7 treatment did not change the ratio of Th2 cells in activated CD4+ T cells, while it increased the ratio of Th1 cells. Gal-7 also induced activated CD4+ T cells to produce a higher level of IFN-γ and TNF-α and a lower level of IL-10. Moreover, Gal-7 treatment significantly accelerated nuclear export of Smad3 in activated CD4+ T cells. These results revealed a novel role of Gal-7 in promoting proliferation and Th1/2 cells polarization toward Th1 in activated CD4+ T cells by inhibiting the TGFβ/Smad3 pathway. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. A Clean, Mild, and Efficient Preparation of Aryl 14H-benzo[a,j]xanthene leuco-dye Derivatives Via Nanocatalytic MCM-41-SO3H Under Ultrasonic Irradiation in Aqueous Media.

    Science.gov (United States)

    Fathollahi, Mostafa; Rostamizadeh, Shahnaz; Amani, Ali M

    2018-01-01

    The present study has developed an efficient and eco-friendly protocol for the synthesis of aryl-14-H-dibenzo[a,j] xanthenes through a one-pot condensation reaction of 2-naphthol and arylaldehydes in aqueous media using the nanocatalytic MCM-41-SO3H under ultrasonic illumination. Using SEM and XRD analyses, MCM-41-SO3H nanoparticles were characterized. Therefore, for high magnification, taking the SEM image, the mesoporous surface of MCM-41-SO3H nanoparticles coated with gold for 2 minutes was characterized. Moreover, at a scan rate of 0.02° (2θ)/sec, XRD analysis from 1.5° (2θ) to 10.0° (2θ) was performed. For our considered sample, some well-ordered XRD patterns with one main peak as well as three minor peaks equal to those of MCM-41 materials were observed. The suggested route demonstrates very promising properties like higher yields, decrease in the time of reaction (5-10 min), mild and straightforward conditions, low level of toxicity, and inclusion of a cost-efficient and ecofriendly catalyst having considerable reusability. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  2. Application of AlMCM-41 for competitive adsorption of methylene blue and rhodamine B: Thermodynamic and kinetic studies

    International Nuclear Information System (INIS)

    Eftekhari, S.; Habibi-Yangjeh, A.; Sohrabnezhad, Sh.

    2010-01-01

    AlMCM-41 was applied for adsorption of methylene blue (MB) and rhodamine B (RB) in single and binary component systems. In the single component systems, AlMCM-41 represents higher adsorption capacity for MB than RB with the maximal adsorption capacity of 2.08 x 10 -4 and 8.74 x 10 -5 mol/g at 25 deg. C for MB and RB, respectively. In the binary component system, MB and RB exhibit competitive adsorption onto the adsorbent. The adsorption is approximately reduced to 94 and 79% of single component adsorption systems for MB and RB (initial concentration of 8 x 10 -6 M) at 25 deg. C. In single and binary component systems, kinetic and adsorption isotherm studies demonstrate that the data are following pseudo-second-order kinetic model and Langmuir isotherm. Effect of solution pH on the adsorption in single and binary component systems was studied and the results were described by electrostatic interactions.

  3. Effect of essential amino acids on enteroids: Methionine deprivation suppresses proliferation and affects differentiation in enteroid stem cells

    International Nuclear Information System (INIS)

    Saito, Yuki; Iwatsuki, Ken; Hanyu, Hikaru; Maruyama, Natsuki; Aihara, Eitaro; Tadaishi, Miki; Shimizu, Makoto; Kobayashi-Hattori, Kazuo

    2017-01-01

    We investigated the effects of essential amino acids on intestinal stem cell proliferation and differentiation using murine small intestinal organoids (enteroids) from the jejunum. By selectively removing individual essential amino acids from culture medium, we found that 24 h of methionine (Met) deprivation markedly suppressed cell proliferation in enteroids. This effect was rescued when enteroids cultured in Met deprivation media for 12 h were transferred to complete medium, suggesting that Met plays an important role in enteroid cell proliferation. In addition, mRNA levels of the stem cell marker leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5) decreased in enteroids grown in Met deprivation conditions. Consistent with this observation, Met deprivation also attenuated Lgr5-EGFP fluorescence intensity in enteroids. In contrast, Met deprivation enhanced mRNA levels of the enteroendocrine cell marker chromogranin A (ChgA) and markers of K cells, enterochromaffin cells, goblet cells, and Paneth cells. Immunofluorescence experiments demonstrated that Met deprivation led to an increase in the number of ChgA-positive cells. These results suggest that Met deprivation suppresses stem cell proliferation, thereby promoting differentiation. In conclusion, Met is an important nutrient in the maintenance of intestinal stem cells and Met deprivation potentially affects cell differentiation. - Highlights: • Met influences the proliferation of enteroids. • Met plays a crucial role in the maintenance of stem cells. • Met deprivation potentially promotes differentiation into secretory cells.

  4. Profile of cell proliferation and apoptosis activated by the intrinsic and extrinsic pathways in the prostate of aging rats.

    Science.gov (United States)

    Gonzaga, Amanda C R; Campolina-Silva, Gabriel H; Werneck-Gomes, Hipácia; Moura-Cordeiro, Júnia D; Santos, Letícia C; Mahecha, Germán A B; Morais-Santos, Mônica; Oliveira, Cleida A

    2017-06-01

    Estrogens acting through the receptors ERα and ERβ participate in prostate normal growth and cancer. ERβ is highly expressed in the prostate epithelium, playing pro-apoptotic, anti-proliferative, and pro-differentiation roles. Apoptosis is activated by the intrinsic pathway after castration and by the extrinsic pathway after ERβ agonist treatment. This differential activation of apoptotic pathways is important since a major problem in the treatment of prostate cancer is the recurrence of tumors after androgen withdrawal. However, a comprehensive study about the pattern of apoptosis in the aging prostate is lacking, a knowledge gap that we aimed to address herein. Cellular age-related proliferative and apoptotic profiles of prostate tissue obtained from aging Wistar rats were evaluated. Cell death (caspase-3, -8, -9, TNFα) was assessed by immunohistochemistry, immunofluorescence, and TUNEL. Cell proliferation (MCM7) and cell survival factors (ERK1/2, p-ERK1/2, p-Akt, and NF-κB) were determined by immunohistochemistry. As the rats aged, the number of proliferating cells gradually reduced in the normal epithelium of all prostate lobes, while increasing in focal areas of intraepithelial proliferation. Interestingly, in areas of intraepithelial proliferation, we observed a reduction in the number of cells positive for caspase-3, -8, and -9. Regardless the animal's age, few prostate epithelial cells were positive for caspase-3, caspase-9, and TUNEL. In contrast, a progressive increase was seen in the positivity for caspase-8, especially in the atrophic epithelium of ventral prostate, which coincided with a reduction in TNFα immunoreaction. However, morphology of most caspase-8 positive cells suggests that they were not apoptotic. We also found reduced ERβ expression in the same areas. Possibly, low levels of the pro-apoptotic inductors TNFα and ERβ direct caspase-8 activity to an alternative pro-survival role in the atrophic epithelium. This hypothesis is

  5. WT1 Is Necessary for the Proliferation and Migration of Cells of Renin Lineage Following Kidney Podocyte Depletion

    Directory of Open Access Journals (Sweden)

    Natalya V. Kaverina

    2017-10-01

    Full Text Available Wilms' tumor suppressor 1 (WT1 plays an important role in cell proliferation and mesenchymal-epithelial balance in normal development and disease. Here, we show that following podocyte depletion in three experimental models, and in patients with focal segmental glomerulosclerosis (FSGS and membranous nephropathy, WT1 increased significantly in cells of renin lineage (CoRL. In an animal model of FSGS in RenWt1fl/fl reporter mice with inducible deletion of WT1 in CoRL, CoRL proliferation and migration to the glomerulus was reduced, and glomerular disease was worse compared with wild-type mice. To become podocytes, CoRL undergo mesenchymal-to-epithelial transformation (MET, typified by reduced staining for mesenchymal markers (MYH11, SM22, αSMA and de novo expression of epithelial markers (E-cadherin and cytokeratin18. Evidence for changes in MET markers was barely detected in RenWt1fl/fl mice. Our results show that following podocyte depletion, WT1 plays essential roles in CoRL proliferation and migration toward an adult podocyte fate.

  6. Protocol for the development of the Master Chemical Mechanism, MCM v3 (Part B: tropospheric degradation of aromatic volatile organic compounds

    Directory of Open Access Journals (Sweden)

    M. E. Jenkin

    2003-01-01

    Full Text Available Kinetic and mechanistic data relevant to the tropospheric degradation of aromatic volatile organic compounds (VOC have been used to define a mechanism development protocol, which has been used to construct degradation schemes for 18 aromatic VOC as part of version 3 of the Master Chemical Mechanism (MCM v3. This is complementary to the treatment of 107 non-aromatic VOC, presented in a companion paper. The protocol is divided into a series of subsections describing initiation reactions, the degradation chemistry to first generation products via a number of competitive routes, and the further degradation of first and subsequent generation products. Emphasis is placed on describing where the treatment differs from that applied to the non-aromatic VOC. The protocol is based on work available in the open literature up to the beginning of 2001, and some other studies known by the authors which were under review at the time. Photochemical Ozone Creation Potentials (POCP have been calculated for the 18 aromatic VOC in MCM v3 for idealised conditions appropriate to north-west Europe, using a photochemical trajectory model. The POCP values provide a measure of the relative ozone forming abilities of the VOC. These show distinct differences from POCP values calculated previously for the aromatics, using earlier versions of the MCM, and reasons for these differences are discussed.

  7. Evaluation of the influence of sulfur-based functional groups on the embedding of silver nanoparticles into the pores of MCM-41

    International Nuclear Information System (INIS)

    Oliveira, Roselaine da S.; Camilo, Fernanda F.; Bizeto, Marcos A.

    2016-01-01

    The incorporation of noble metals in the pores of mesoporous silicas might produce materials with interesting catalytic and sensing capabilities, but the proper control of pore filling and the avoidance of nanoparticles migration to outside the pores are processes not yet completely understood. In this work, we evaluated the role of –SH and –SO_3H groups post-grafted into MCM-41 on the production of silver nanoparticles by using 1-butanol as reducing agent. Thiol groups were the most efficient on promoting the formation of nanoparticles within the pores. Conversely, sulfonic groups establish electrostatic interactions with silver cations that preclude the formation of nanoparticle in yields comparable to thiol groups. MCM-41 without functional groups did not have good affinity to silver and the nanoparticles are produced outside the pores. This study showed the importance on selecting an adequate surface functional group in order to obtain silver nanoparticles filling the pores of MCM-41. - Graphical abstract: Silver nanoparticles formation inside the pores of sulfur-groups functionalized mesoporous silica. - Highlights: • Silver nanoparticles formation inside the pores of mesoporous silica. • n-butanol as reducing agent of impregnated silver cations. • Tuning the silica surface properties by grafting sulfur-based functional groups. • Influence on the loading and distribution of the nanoparticles through the pores.

  8. Effects of hydroxyapatite nanoparticles on proliferation and apoptosis of human breast cancer cells (MCF-7)

    International Nuclear Information System (INIS)

    Meena, Ramovatar; Kesari, Kavindra Kumar; Rani, Madhu; Paulraj, R.

    2012-01-01

    The study aimed to correlate cell proliferation inhibition with oxidative stress and p53 protein expression in cancerous cells. Hydroxyapatite (HAP) (Ca 10 (PO 4 ) 6 (OH) 2 ) is the essential component of inorganic composition in human bone. It has been found to have obvious inhibitory function on growth of many kinds of tumor cells and its nanoparticle has stronger anti-cancerous effect than macromolecule microparticles. Human breast cancer cells (MCF-7) were cultured and treated with HAP nanoparticles at various concentrations. Cells viability was detected with MTT colorimetric assay. The morphology of the cancerous cells was performed by transmission electron microscopy and the expression of a cell apoptosis related gene (p53) was determined by ELISA assay and flow cytometry (FCM). The intracellular reactive oxygen species (ROS) level in HAP exposed cells was measured by H 2 DCFDA staining. DNA damage was measured by single-cell gel electrophoresis assay. The statistical analysis was done by one way ANOVA. The cellular proliferation inhibition rate was significantly (p < 0.05) increasing in a dose-dependent manner of HAP nanoparticles. Cell apoptotic characters were observed after MCF-7 cells were treated by HAP nanoparticles for 48 h. Moreover, ELISA assay and FCM shows a dose-dependent activation of p53 in MCF-7 cells treated with nanoHAP. These causative factors of the above results may be justified by an overproduction of ROS. In this study, a significant (p < 0.05) increase in the level of intracellular ROS in HAP-treated cells was observed. This study shows that HAP inhibits the growth of human breast cancer MCF-7 cells as well as induces cell apoptosis. This study shows that HAP NPs Induce the production of intracellular reactive oxygen species and activate p53, which may be responsible for DNA damage and cell apoptosis.

  9. Experimental Study of the Effect of Si/Al Composition on the Aluminum Distribution in (Al)MCM-41

    Czech Academy of Sciences Publication Activity Database

    Dědeček, Jiří; Žilková, Naděžda; Čejka, Jiří

    44-45, 1/3 (2001), s. 259-266 ISSN 1387-1811 R&D Projects: GA AV ČR IAA4040001; GA AV ČR IBS4040017 Institutional research plan: CEZ:AV0Z4040901 Keywords : (Al)MCM-41 * Al distribution * VIS spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.497, year: 2001

  10. A MCM-D-type module for the ATLAS pixel detector

    CERN Document Server

    Becks, K H; Ehrmann, O; Gerlach, P; Gregor, I M; Pieters, P; Topper, M; Truzzi, C; Wolf, J

    1999-01-01

    For the ATLAS experiment at the planned Large Hadron Collider LHC at CERN hybrid pixel detectors are being built as innermost layers of the inner tracking detector system. Modules are the basic building blocks of the ATLAS pixel $9 detector. A module consists of a sensor tile with an active area of 16.4 mm*60.4 mm, 16 read out IC's, each serving 24*160 pixel unit cells, a module controller chip, an optical transceiver and the local signal interconnection and $9 power distribution busses. The dies are attached by flip-chip assembly to the sensor diodes and the local busses. In the following a module based on MCM-D technology will be discussed and prototype results will be presented.

  11. Uranium adsorption studies on aminopropyl modified mesoporous sorbent (NH{sub 2}-MCM-41) using statistical design method

    Energy Technology Data Exchange (ETDEWEB)

    Sert, Senol, E-mail: senol.sert@ege.edu.t [Ege University, Institute of Nuclear Sciences, 35100 Bornova-Izmir (Turkey); Eral, Meral [Ege University, Institute of Nuclear Sciences, 35100 Bornova-Izmir (Turkey)

    2010-11-30

    MCM-41 has been synthesized and modified in order to graft amine groups on its surface. The modified NH{sub 2}-MCM-41 adsorbent was characterized by using XRD, SEM, surface area and porosity analyzer, and FT-IR. This characterized adsorbent was investigated for uranium adsorption using the batch method. The central composite design (CCD) combined with the response surface methodology (RSM) was selected to determine the effects of parameters and their interactions for the removal of UO{sub 2}{sup 2+} ions. The optimum values of the parameters determined were 4.2 for the initial pH, 60 {sup o}C for the temperature, 90 mg L{sup -1} for the initial concentration and 173 min for the shaking time using the response surface methodology. {Delta}H{sup o} and {Delta}S{sup o} were calculated from the slope and the intercept of plots of ln K{sub d} versus 1/T. The isotherm models, Langmuir, Freundlich, Dubinin-Radushkevich (D-R) have been studied to explain the adsorption characteristics.

  12. Zero-valent Fe confined mesoporous silica nanocarriers (Fe(0) @ MCM-41) for targeting experimental orthotopic glioma in rats

    Science.gov (United States)

    Shevtsov, M. A.; Parr, M. A.; Ryzhov, V. A.; Zemtsova, E. G.; Arbenin, A. Yu; Ponomareva, A. N.; Smirnov, V. M.; Multhoff, G.

    2016-01-01

    Mesoporous silica nanoparticles (MSNs) impregnated with zero-valent Fe (Fe(0) @ MCM-41) represent an attractive nanocarrier system for drug delivery into tumor cells. The major goal of this work was to assess whether MSNs can penetrate the blood-brain barrier in a glioblastoma rat model. Synthesized MSNs nanomaterials were characterized by energy dispersive X-ray spectroscopy, measurements of X-ray diffraction, scanning electron microscopy and Mössbauer spectroscopy. For the detection of the MSNs by MR and for biodistribution studies MSNs were labeled with zero-valent Fe. Subsequent magnetometry and nonlinear-longitudinal-response-M2 (NLR-M2) measurements confirmed the MR negative contrast enhancement properties of the nanoparticles. After incubation of different tumor (C6 glioma, U87 glioma, K562 erythroleukemia, HeLa cervix carcinoma) and normal cells such as fibroblasts and peripheral blood mononuclear cells (PBMCs) MSNs rapidly get internalized into the cytosol. Intracellular residing MSNs result in an enhanced cytotoxicity as Fe(0) @ MCM-41 promote the reactive oxygen species production. MRI and histological studies indicated an accumulation of intravenously injected Fe(0) @ MCM-41 MSNs in orthotopic C6 glioma model. Biodistribution studies with measurements of second harmonic of magnetization demonstrated an increased and dose-dependent retention of MSNs in tumor tissues. Taken together, this study demonstrates that MSNs can enter the blood-brain barrier and accumulate in tumorous tissues. PMID:27386761

  13. Prognostic molecular markers in early breast cancer

    International Nuclear Information System (INIS)

    Esteva, Francisco J; Hortobagyi, Gabriel N

    2004-01-01

    A multitude of molecules involved in breast cancer biology have been studied as potential prognostic markers. In the present review we discuss the role of established molecular markers, as well as potential applications of emerging new technologies. Those molecules used routinely to make treatment decisions in patients with early-stage breast cancer include markers of proliferation (e.g. Ki-67), hormone receptors, and the human epidermal growth factor receptor 2. Tumor markers shown to have prognostic value but not used routinely include cyclin D 1 and cyclin E, urokinase-like plasminogen activator/plasminogen activator inhibitor, and cathepsin D. The level of evidence for other molecular markers is lower, in part because most studies were retrospective and not adequately powered, making their findings unsuitable for choosing treatments for individual patients. Gene microarrays have been successfuly used to classify breast cancers into subtypes with specific gene expression profiles and to evaluate prognosis. RT-PCR has also been used to evaluate expression of multiple genes in archival tissue. Proteomics technologies are in development

  14. Response to Extreme Temperatures of Mesoporous Silica MCM-41: Porous Structure Transformation Simulation and Modification of Gas Adsorption Properties.

    Science.gov (United States)

    Zhang, Shenli; Perez-Page, Maria; Guan, Kelly; Yu, Erick; Tringe, Joseph; Castro, Ricardo H R; Faller, Roland; Stroeve, Pieter

    2016-11-08

    Molecular dynamics (MD) and Monte Carlo (MC) simulations were applied together for the first time to reveal the porous structure transformation mechanisms of mesoporous silica MCM-41 subjected to temperatures up to 2885 K. Silica was experimentally characterized to inform the models and enable prediction of changes in gas adsorption/separation properties. MD simulations suggest that the pore closure process is activated by a collective diffusion of matrix atoms into the porous region, accompanied by bond reformation at the surface. Degradation is kinetically limited, such that complete pore closure is postponed at high heating rates. We experimentally observe decreased gas adsorption with increasing temperature in mesoporous silica heated at fixed rates, due to pore closure and structural degradation consistent with simulation predictions. Applying the Kissinger equation, we find a strong correlation between the simulated pore collapse temperatures and the experimental values which implies an activation energy of 416 ± 17 kJ/mol for pore closure. MC simulations give the adsorption and selectivity for thermally treated MCM-41, for N 2 , Ar, Kr, and Xe at room temperature within the 1-10 000 kPa pressure range. Relative to pristine MCM-41, we observe that increased surface roughness due to decreasing pore size amplifies the difference of the absolute adsorption amount differently for different adsorbate molecules. In particular, we find that adsorption of strongly interacting molecules can be enhanced in the low-pressure region while adsorption of weakly interacting molecules is inhibited. This then results in higher selectivity in binary mixture adsorption in mesoporous silica.

  15. Decay dynamics of blue-green luminescence in meso-porous MCM-41 nanotubes

    International Nuclear Information System (INIS)

    Lee, Y.C.; Liu, Y.L.; Wang, C.K.; Shen, J.L.; Cheng, P.W.; Cheng, C.F.; Ko, C.-H.; Lin, T.Y.

    2005-01-01

    Time-resolved photoluminescence (PL) was performed to investigate the decay of blue-green luminescence in MCM-41 nanotubes. The PL decay exhibits a clear nonexponential profile, which can be fitted by a stretched exponential function. In the temperature range from 50 to 300 K the photogenerated carriers become thermally activated with a characteristic energy of 29 meV, which is an indication of the phonon-assisted nonradiative process. The temperature dependence of the lifetime of PL decay has been explained using a model based on the radiative recombination of localized carriers and the phonon-assisted nonradiative recombination

  16. Dedifferentiation and proliferation of mammalian cardiomyocytes.

    Directory of Open Access Journals (Sweden)

    Yiqiang Zhang

    2010-09-01

    Full Text Available It has long been thought that mammalian cardiomyocytes are terminally-differentiated and unable to proliferate. However, myocytes in more primitive animals such as zebrafish are able to dedifferentiate and proliferate to regenerate amputated cardiac muscle.Here we test the hypothesis that mature mammalian cardiomyocytes retain substantial cellular plasticity, including the ability to dedifferentiate, proliferate, and acquire progenitor cell phenotypes. Two complementary methods were used: 1 cardiomyocyte purification from rat hearts, and 2 genetic fate mapping in cardiac explants from bi-transgenic mice. Cardiomyocytes isolated from rodent hearts were purified by multiple centrifugation and Percoll gradient separation steps, and the purity verified by immunostaining and RT-PCR. Within days in culture, purified cardiomyocytes lost their characteristic electrophysiological properties and striations, flattened and began to divide, as confirmed by proliferation markers and BrdU incorporation. Many dedifferentiated cardiomyocytes went on to express the stem cell antigen c-kit, and the early cardiac transcription factors GATA4 and Nkx2.5. Underlying these changes, inhibitory cell cycle molecules were suppressed in myocyte-derived cells (MDCs, while microRNAs known to orchestrate proliferation and pluripotency increased dramatically. Some, but not all, MDCs self-organized into spheres and re-differentiated into myocytes and endothelial cells in vitro. Cell fate tracking of cardiomyocytes from 4-OH-Tamoxifen-treated double-transgenic MerCreMer/ZEG mouse hearts revealed that green fluorescent protein (GFP continues to be expressed in dedifferentiated cardiomyocytes, two-thirds of which were also c-kit(+.Contradicting the prevailing view that they are terminally-differentiated, postnatal mammalian cardiomyocytes are instead capable of substantial plasticity. Dedifferentiation of myocytes facilitates proliferation and confers a degree of stemness

  17. The effects of 6-gingerol on proliferation, differentiation, and maturation of osteoblast-like MG-63 cells

    Energy Technology Data Exchange (ETDEWEB)

    Fan, J.Z.; Yang, X.; Bi, Z.G. [Department of Orthopedic Surgery, First Affiliated Hospital, Harbin Medicine University, Harbin (China)

    2015-04-28

    We investigated whether 6-gingerol affects the maturation and proliferation of osteoblast-like MG63 cells in vitro. Osteoblast-like MG63 cells were treated with 6-gingerol under control conditions, and experimental inflammation was induced by tumor necrosis factor-α (TNF-α). Expression of different osteogenic markers and cytokines was analyzed by real-time PCR, Western blotting, and enzyme-linked immunosorbent assay. In addition, alkaline phosphatase (ALP) enzyme activity and biomineralization as markers for differentiation were measured. Treatment with 6-gingerol resulted in insignificant effects on the proliferation rate. 6-Gingerol induced the differentiation of osteoblast-like cells with increased transcription levels of osteogenic markers, upregulated ALP enzyme activity, and enhanced mineralized nodule formation. Stimulation with TNF-α led to enhanced interleukin-6 and nuclear factor-κB expression and downregulated markers of osteoblastic differentiation. 6-Gingerol reduced the degree of inflammation in TNF-α-treated MG-63 cells. In conclusion, 6-gingerol stimulated osteoblast differentiation in normal physiological and inflammatory settings, and therefore, 6-gingerol represents a promising agent for treating osteoporosis or bone inflammation.

  18. Combined microcalorimetric and IR spectroscopic study on carbon dioxide adsorption in H-MCM-22

    Energy Technology Data Exchange (ETDEWEB)

    Arean, C.O., E-mail: co.arean@uib.es [Department of Chemistry, University of the Balearic Islands, 07122 Palma de Mallorca (Spain); Delgado, M.R. [Department of Chemistry, University of the Balearic Islands, 07122 Palma de Mallorca (Spain); Bulánek, R.; Frolich, K. [Department of Physical Chemistry, Faculty of Chemical Technology, University of Pardubice, 532 10 Pardubice (Czech Republic)

    2014-10-15

    Highlights: • Adsorption calorimetry and variable temperature IR spectroscopy is used to study adsorption of CO{sub 2} in the protonic zeolite H-MCM-22. • By simultaneously recording IR absorbance over a temperature range, temperature and equilibrium pressure, standard adsorption enthalpy and entropy of CO{sub 2} was determined. • The results are discussed in the broader context of carbon dioxide capture from the flue gas of fossil fuel fired power stations. - Abstract: The thermodynamics of carbon dioxide adsorption in the protonic zeolite H-MCM-22 (Si:Al = 16:1) was investigated by means of adsorption calorimetry and variable-temperature IR spectroscopy, a technique that affords determination of standard adsorption enthalpy (ΔH{sup 0}) and entropy (ΔS{sup 0}) from analysis of a series of IR spectra recorded over a temperature range while simultaneously measuring equilibrium pressure inside a closed IR cell. ΔH{sup 0} resulted to be −24.5 (±2) kJ mol{sup −1}, while for the entropy change the value of ΔS{sup 0} = −115 (±10) J mol{sup −1} K{sup −1} was obtained. The obtained ΔH{sup 0} value is compared with those reported in the literature for the adsorption of CO{sub 2} on other zeolites, and discussed in the context of carbon dioxide capture and sequestration.

  19. Pimonidazole: a novel hypoxia marker for complementary study of tumor hypoxia and tumor biology

    International Nuclear Information System (INIS)

    Varia, Mahesh A.; Kennedy, Andrew S.; Calkins-Adams, Dennise P.; Rinker, Lillian; Novotny, Debra; Fowler, Wesley C.; Raleigh, James A.

    1997-01-01

    Purpose/Objectives: Tumor hypoxia appears to be associated with treatment resistance and with gene expression that may lead to hypoxia-mediated selection of tumor cells as a source for cell growth and metastases. The objective of this study was to develop complementary techniques of hypoxia detection with molecular markers of cell proliferation and metastases in order to investigate the role of tumor hypoxia in tumor biology. Materials and Methods: Pimonidazole is a 2-nitroimidazole which is reductively-activated and becomes covalently bound to thiol-containing proteins only in hypoxic cells. These adducts can be detected using immunohistochemistry, enzyme linked immunosorbent assay or flow cytometry as a measure of hypoxia in tumors. Quantitative immunohistochemical analysis has been completed for five patients with squamous cell carcinoma of the cervix who were given pimonidazole hydrochloride (0.5 g/m 2 intravenously) followed by cervical biopsies 24 hours later. Informed consent was obtained according to a protocol approved by the Institutional Review Board. A minimum of 3 random biopsies were obtained from the tumors and at least four sections examined from each biopsy site. Formalin fixed, paraffin embedded tissue sections were immunostained for pimonidazole binding using a mouse monoclonal antibody. Commercially available monoclonal antibodies were used to detect cell proliferation markers MIB-1 (Ki-67) and to detect vascular endothelial growth factor (VEGF) in tumor cells in contiguous sections. The extent of immunostaining was expressed as the percent of immunostained to total tumor cells as determined by Chalkley point counting. Results: No clinical toxicities were associated with pimonidazole infusion. Immunostaining with pimonidazole antibody was observed in all patients indicating the presence of tumor hypoxia. Qualitatively there is little or no overlap between the areas of hypoxia and proliferation. Quantitative data tabulated below show the

  20. A Role of hIPI3 in DNA Replication Licensing in Human Cells.

    Science.gov (United States)

    Huang, Yining; Amin, Aftab; Qin, Yan; Wang, Ziyi; Jiang, Huadong; Liang, Lu; Shi, Linjing; Liang, Chun

    2016-01-01

    The yeast Ipi3p is required for DNA replication and cell viability in Sacharomyces cerevisiae. It is an essential component of the Rix1 complex (Rix1p/Ipi2p-Ipi1p-Ipi3p) that is required for the processing of 35S pre-rRNA in pre-60S ribosomal particles and for the initiation of DNA replication. The human IPI3 homolog is WDR18 (WD repeat domain 18), which shares significant homology with yIpi3p. Here we report that knockdown of hIPI3 resulted in substantial defects in the chromatin association of the MCM complex, DNA replication, cell cycle progression and cell proliferation. Importantly, hIPI3 silencing did not result in a reduction of the protein level of hCDC6, hMCM7, or the ectopically expressed GFP protein, indicating that protein synthesis was not defective in the same time frame of the DNA replication and cell cycle defects. Furthermore, the mRNA and protein levels of hIPI3 fluctuate in the cell cycle, with the highest levels from M phase to early G1 phase, similar to other pre-replicative (pre-RC) proteins. Moreover, hIPI3 interacts with other replication-initiation proteins, co-localizes with hMCM7 in the nucleus, and is important for the nuclear localization of hMCM7. We also found that hIPI3 preferentially binds to the origins of DNA replication including those at the c-Myc, Lamin-B2 and β-Globin loci. These results indicate that hIPI3 is involved in human DNA replication licensing independent of its role in ribosome biogenesis.