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Sample records for enhanced antiproliferative properties

  1. The "Janus face" of the thrombin binding aptamer: Investigating the anticoagulant and antiproliferative properties through straightforward chemical modifications.

    Science.gov (United States)

    Esposito, Veronica; Russo, Annapina; Amato, Teresa; Vellecco, Valentina; Bucci, Mariarosaria; Mayol, Luciano; Russo, Giulia; Virgilio, Antonella; Galeone, Aldo

    2018-02-01

    The thrombin binding aptamer (TBA) is endowed with both anticoagulant and antiproliferative activities. Its chemico-physical and/or biological properties can be tuned by the site-specific replacement of selected residues. Four oligodeoxynucleotides (ODNs) based on the TBA sequence (5'-GGTTGGTGTGGTTGG-3') and containing 2'-deoxyuridine (U) or 5-bromo-2'-deoxyuridine (B) residues at positions 4 or 13 have been investigated by NMR and CD techniques. Furthermore, their anticoagulant (PT assay) and antiproliferative properties (MTT assay) have been tested and compared with two further ODNs containing 5-hydroxymethyl-2'-deoxyuridine (H) residues in the same positions, previously investigated. The CD and NMR data suggest that all the investigated ODNs are able to form G-quadruplexes strictly resembling that of TBA. The introduction of B residues in positions 4 or 13 increases the melting temperature of the modified aptamers by 7 °C. The replacement of thymidines with U in the same positions results in an enhanced anticoagulant activity compared to TBA, also at low ODN concentration. Although all ODNs show antiproliferative properties, only TBA derivatives containing H in the positions 4 and 13 lose the anticoagulant activity and remarkably preserve the antiproliferative one. All ODNs have shown antiproliferative activities against two cancer cell lines but only those with U and B are endowed with anticoagulant activities similar or improved compared to TBA. The appropriate site-specific replacement of the residues in the TT loops of TBA with commercially available thymine analogues is a useful strategy either to improve the anticoagulant activity or to preserve the antiproliferative properties by quenching the anticoagulant ones. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Discovery of nitroaryl urea derivatives with antiproliferative properties

    Czech Academy of Sciences Publication Activity Database

    Wrobel, T.M.; Kielbus, M.; Kaczor, A.A.; Kryštof, Vladimír; Karczmarzyk, Z.; Wysocki, W.; Fruzinski, A.; Król, S.; Grabarska, A.; Stepulak, A.; Matosiuk, D.

    2016-01-01

    Roč. 31, č. 4 (2016), s. 608-618 ISSN 1475-6366 R&D Projects: GA ČR(CZ) GA15-15264S Institutional support: RVO:61389030 Keywords : Antiproliferative * cancer * CDK inhibitor Subject RIV: FR - Pharmacology ; Medidal Chemistry Impact factor: 4.293, year: 2016

  3. Screening antimutagenic and antiproliferative properties of extracts isolated from Jackfruit pulp (Artocarpus heterophyllus Lam).

    Science.gov (United States)

    Ruiz-Montañez, G; Burgos-Hernández, A; Calderón-Santoyo, M; López-Saiz, C M; Velázquez-Contreras, C A; Navarro-Ocaña, A; Ragazzo-Sánchez, J A

    2015-05-15

    The present focused on the study of the antimutagenic and antiproliferative potential of pulp Jackfruit (Artocarpus heterophyllus Lam) extract, using Salmonella typhimurium tester strains TA98 and TA100 with metabolic activation (S9) and a cancer cell line M12.C3.F6 (murine B-cell lymphoma), respectively. Jackfruit pulp extract was sequentially fractionated by chromatography (RP-HPLC) and each fraction was tested for antimutagenic and antiproliferative activities. The organic extracts obtained from Jackfruit pulp reduced the number of revertants caused by aflatoxin B1 (AFB1) and proliferation of cells M12.C3.F6; a dose-response relationship was showed. Sequential RP-HPLC fractionation of the active extracts produced both antimutagenic and/or antiproliferative fractions. These results suggested that the Jackfruit contained compounds with chemoprotective properties to reduce the mutagenicity of AFB1, also proliferation of a cancer cell line. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Diethylene glycol monoethyl ether (Transcutol) displays antiproliferative properties alone and in combination with xanthines.

    Science.gov (United States)

    Levi-Schaffer, F; Dayan, N; Touitou, E

    1996-01-01

    In the present study we have investigated the effects of diethylene glycol monoethyl ether (Transcutol) in combination with theophylline, caffeine and dyphylline and alone on 3T3 mouse fibroblast proliferation. These three xanthines (1-0.01 mM) inhibited fibroblast proliferation by themselves. Enhancement of the effect was detected by addition of 1 and 0.1 mM Transcutol. Transcutol alone also displayed a dose-dependent inhibition (2-0.01 mM) of both 3T3 and human normal and psoriatic fibroblasts, although normal human fibroblasts were the least sensitive to Transcutol antiproliferative activity. Transcutol was assessed for its antiproliferative effects on YAC lymphoma and P-815 mastocytoma human cell lines. Transcutol inhibited cell proliferation of both these cell lines, being more effective towards P-815 mastocytoma (at 2 mM it displayed 3.95-fold vs. 2.4-fold inhibition towards YAC lymphoma). In conclusion, we have shown that Transcutol has antiproliferative effects on 3T3 murine, human normal and psoriatic fibroblasts and tumour cell lines. In addition it enhances xanthine antiproliferative effects on 3T3 fibroblasts. Therefore it might be a useful topical drug alone or in combination with xanthines in the treatment of skin hyperproliferative disorders.

  5. Arctigenin in combination with quercetin synergistically enhances the anti-proliferative effect in prostate cancer cells

    Science.gov (United States)

    Wang, Piwen; Phan, Tien; Gordon, David; Chung, Seyung; Henning, Susanne M.; Vadgama, Jaydutt V.

    2014-01-01

    Scope We investigated whether a combination of two promising chemopreventive agents arctigenin and quercetin increases the anti-carcinogenic potency at lower concentrations than necessary when used individually in prostate cancer. Methods and results Androgen-dependent LAPC-4 and LNCaP prostate cancer cells were treated with low doses of arctigenin and quercetin alone or in combination for 48h. The anti-proliferative activity of arctigenin was 10-20 fold stronger than quercetin in both cell lines. Their combination synergistically enhanced the anti-proliferative effect, with a stronger effect in androgen receptor (AR) wild-type LAPC-4 cells than in AR mutated LNCaP cells. Arctigenin demonstrated a strong ability to inhibit AR protein expression in LAPC-4 cells. The combination treatment significantly inhibited both AR and PI3K/Akt pathways compared to control. A protein array analysis revealed that the mixture targets multiple pathways particularly in LAPC-4 cells including Stat3 pathway. The mixture significantly inhibited the expression of several oncogenic microRNAs including miR-21, miR-19b, and miR-148a compared to control. The mixture also enhanced the inhibition of cell migration in both cell lines compared to individual compounds tested. Conclusion The combination of arctigenin and quercetin, that target similar pathways, at low physiological doses, provides a novel regimen with enhanced chemoprevention in prostate cancer. PMID:25380086

  6. Arctigenin in combination with quercetin synergistically enhances the antiproliferative effect in prostate cancer cells.

    Science.gov (United States)

    Wang, Piwen; Phan, Tien; Gordon, David; Chung, Seyung; Henning, Susanne M; Vadgama, Jaydutt V

    2015-02-01

    We investigated whether a combination of two promising chemopreventive agents arctigenin (Arc) and quercetin (Q) increases the anticarcinogenic potency at lower concentrations than necessary when used individually in prostate cancer. Androgen-dependent LAPC-4 and LNCaP prostate cancer cells were treated with low doses of Arc and Q alone or in combination for 48 h. The antiproliferative activity of Arc was 10- to 20-fold stronger than Q in both cell lines. Their combination synergistically enhanced the antiproliferative effect, with a stronger effect in androgen receptor (AR) wild-type LAPC-4 cells than in AR mutated LNCaP cells. Arc demonstrated a strong ability to inhibit AR protein expression in LAPC-4 cells. The combination treatment significantly inhibited both AR and PI3K/Akt pathways compared to control. A protein array analysis revealed that the mixture targets multiple pathways particularly in LAPC-4 cells including Stat3 pathway. The mixture significantly inhibited the expression of several oncogenic microRNAs including miR-21, miR-19b, and miR-148a compared to control. The mixture also enhanced the inhibition of cell migration in both cell lines compared to individual compounds tested. The combination of Arc and Q that target similar pathways, at low physiological doses, provides a novel regimen with enhanced chemoprevention in prostate cancer. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Enhanced and Selective Antiproliferative Activity of Methotrexate-Functionalized-Nanocapsules to Human Breast Cancer Cells (MCF-7

    Directory of Open Access Journals (Sweden)

    Catiúscia P. de Oliveira

    2018-01-01

    Full Text Available Methotrexate is a folic acid antagonist and its incorporation into nanoformulations is a promising strategy to increase the drug antiproliferative effect on human breast cancer cells by overexpressing folate receptors. To evaluate the efficiency and selectivity of nanoformulations containing methotrexate and its diethyl ester derivative, using two mechanisms of drug incorporation (encapsulation and surface functionalization in the in vitro cellular uptake and antiproliferative activity in non-tumoral immortalized human keratinocytes (HaCaT and in human breast carcinoma cells (MCF-7. Methotrexate and its diethyl ester derivative were incorporated into multiwall lipid-core nanocapsules with hydrodynamic diameters lower than 160 nm and higher drug incorporation efficiency. The nanoformulations were applied to semiconfluent HaCaT or MCF-7 cells. After 24 h, the nanocapsules were internalized into HaCaT and MCF-7 cells; however, no significant difference was observed between the nanoformulations in HaCaT (low expression of folate receptors, while they showed significantly higher cellular uptakes than the blank-nanoformulation in MCF-7, which was the highest uptakes observed for the drug functionalized-nanocapsules. No antiproliferative activity was observed in HaCaT culture, whereas drug-containing nanoformulations showed antiproliferative activity against MCF-7 cells. The effect was higher for drug-surface functionalized nanocapsules. In conclusion, methotrexate-functionalized-nanocapsules showed enhanced and selective antiproliferative activity to human breast cancer cells (MCF-7 being promising products for further in vivo pre-clinical evaluations.

  8. Phytochemical Constituents, ChEs and Urease Inhibitions, Antiproliferative and Antioxidant Properties of Elaeagnus umbellata Thunb.

    Science.gov (United States)

    Ozen, Tevfik; Yenigun, Semiha; Altun, Muhammed; Demirtas, Ibrahim

    2017-01-01

    Due to the common ethnopharmacological used or scientifically examined biochemical properties, Elaeagnaceae family, Elaeagnus umbellate (Thunb.) (EU, Guz yemisi) was worth investigating. In this investigation, we revealed antioxidant, antiproliferative and enzyme inhibition activities of the water, methanol, ethanol, acetone, ethyl acetate and hexane extracts of EU as well as the contents of their phenolic, flavonoid, anthocyanin, ascorbic acid, lycopene and β- carotene. The antioxidant activity was screened by total antioxidant (phosphomolybdenum), inhibition of linoleic acid peroxidation, reducing power, 2-deoxyribose degradation assay, H2O2 scavenging and metal chelating activities of the samples were tested in vitro. Additionally, the scavenging activities of the extracts were determined against 1,1-diphenyl-2-picrylhydrazyl (DPPH˙), 2,2-azino-bis(3-ethylbenzothiazloine-6-sulfonicacid (ABTS˙+), superoxide anion and peroxide radicals. The samples were determined for their inhibitory activities against urease, acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). In vitro, antiproliferative activities of six different extracts were tested using the xCELLigence system against HeLa and HT29 cell lines. The antioxidant activities of the extracts were found higher than standard antioxidants. The water extracts of fruit and leaf showed the best antioxidant activity. In inhibition assays of urease, AChE and BuChE, all extracts exhibited remarkable inhibition potential. Ethyl acetate extracts, especially, showed better inhibition capacity. It was found that the antioxidant activities of the extracts presented consistently with their chemical contents. The antiproliferative activities of leaf extracts were more effective than the fruit extracts. The chromatographic methods were applied to the different solvents to analyses phenolic secondery metabolites. It was found that fumaric acid, 4- hydroxybenzoic acid, rutin and quercetin-3-

  9. Bioactive properties of commercialised pomegranate (Punica granatum) juice: antioxidant, antiproliferative and enzyme inhibiting activities.

    Science.gov (United States)

    Les, Francisco; Prieto, Jose M; Arbonés-Mainar, Jose Miguel; Valero, Marta Sofía; López, Víctor

    2015-06-01

    Pomegranate juice and related products have long been used either in traditional medicine or as nutritional supplements claiming beneficial effects. Although there are several studies on this food plant, only a few studies have been performed with pomegranate juice or marketed products. The aim of this work is to evaluate the antioxidant effects of pomegranate juice on cellular models using hydrogen peroxide as an oxidizing agent or DPPH and superoxide radicals in cell free systems. The antiproliferative effects of the juice were measured on HeLa and PC-3 cells by the MTT assay and pharmacologically relevant enzymes (cyclooxygenases, xanthine oxidase, acetylcholinesterase and monoamine oxidase A) were selected for enzymatic inhibition assays. Pomegranate juice showed significant protective effects against hydrogen peroxide induced toxicity in the Artemia salina and HepG2 models; these effects may be attributed to radical scavenging properties of pomegranate as the juice was able to reduce DPPH and superoxide radicals. Moderate antiproliferative activities in HeLa and PC-3 cancer cells were observed. However, pomegranate juice was also able to inhibit COX-2 and MAO-A enzymes. This study reveals some mechanisms by which pomegranate juice may have interesting and beneficial effects in human health.

  10. Isoliquiritigenin exhibits anti-proliferative properties in the pituitary independent of estrogen receptor function

    International Nuclear Information System (INIS)

    Weis, Karen E.; Raetzman, Lori T.

    2016-01-01

    The plant flavonoid isoliquiritigenin (ISL) is a botanical estrogen widely taken as an herbal supplement to ease the symptoms of menopause. ISL has been also shown to have anti-tumor properties in a number of cancer cell backgrounds. However, the effects of ISL on normal cells are less well known and virtually unstudied in the context of the pituitary gland. We have established a pituitary explant culture model to screen chemical agents for gene expression changes within the pituitary gland during a period of active proliferation and differentiation. Using this whole-organ culture system we found ISL to be weakly estrogenic based on its ability to induce Cckar mRNA expression, an estrogen receptor (ER) mediated gene. Using a range of ISL from 200 nM to 200 μM, we discovered that ISL promoted cell proliferation at a low concentration, yet potently inhibited proliferation at the highest concentration. ICI 182,780 failed to antagonize ISL's repression of pituitary cell proliferation, indicating the effect is independent of ER signaling. Coincident with a decrease in proliferating cells, we observed down-regulation of transcript for cyclin D2 and E2 and a strong induction of mRNA and protein for the cyclin dependent kinase inhibitor Cdkn1a (p21). Importantly, high dose ISL did not alter the balance of progenitor vs. differentiated cell types within the pituitary explants and they seemed otherwise healthy; however, TUNEL staining revealed an increase in apoptotic cell death in ISL treated cultures. Our results merit further examination of ISL as an anti-tumor agent in the pituitary gland. - Highlights: • Isoliquiritigenin possesses weak estrogenic activity based on induction of Cckar. • ISL can be anti-proliferative in pituitary explants without altering cell lineages. • Anti-proliferative behavior of ISL is not estrogen receptor mediated. • ISL induces p21 expression leading to cell cycle arrest and apoptosis.

  11. In vitro evaluation of antiproliferative and cytotoxic properties of pterostilbene against human colon cancer cells.

    Science.gov (United States)

    Wawszczyk, Joanna; Kapral, Małgorzata; Hollek, Andrzej; Węglarz, Ludmiła

    2014-01-01

    Colon cancer has been remaining the second leading cause of cancer mortality in Poland in the last years. Epidemiological, preclinical and clinical studies reveal that dietary phytochemicals may exert chemopreventive and therapeutic effect against colorectal cancer. There is a growing interest in identifying new biologically active agents from dietary sources in this respect. Pterostilbene (trans-3,5-dimethoxy-4-hydroxystilbene) is a naturally occurring stilbene, that has been found to have antioxidative, anti-inflammatory and antipro- liferative properties. Compared to other stilbenes, pterostilbene has greater bioavailability, and so, a greater potential for clinical applications. Recent studies showed that pterostilbene exhibits the hallmark characteristics of an anticancer agent. The aim of this study was to analyze antiproliferative and cytotoxic effects of pterostilbene on human colon cancer Caco-2 cells. They were cultured using standard techniques and exposed to increasing doses of pterostilbene (5-100 μM) for 48 and 72 h. Cell proliferation was determined by sulforhodamine B assay. The growth of treated cells was expressed as a percentage of that of untreated control cells. Pterostilbene decreased proliferation rate of Caco-2 cells in a dose- and time-dependent manner. Its concentrations = 25 μM did not affect cell growth after 48 h treatment period. Significant growth inhibition was observed in cultures incubated with higher concentrations of pterostilbene (40-100 μM). Pterostilbene at all concentrations used (5-100 μM) caused significant inhibition of cell proliferation when the experimental time period was elongated to 72 h. The maximum growth reduction was observed at 100 mM pterostilbene. The cytotoxicity of pterostilbene was evaluated in 48 h cultures based on lactate dehydrogenase (LDH) leakage into the culture medium and showed dose-related pattern. The findings of this study showed significant dose-dependent antiproliferative and cytotoxic

  12. Isoliquiritigenin exhibits anti-proliferative properties in the pituitary independent of estrogen receptor function

    Energy Technology Data Exchange (ETDEWEB)

    Weis, Karen E.; Raetzman, Lori T., E-mail: raetzman@life.illinois.edu

    2016-12-15

    The plant flavonoid isoliquiritigenin (ISL) is a botanical estrogen widely taken as an herbal supplement to ease the symptoms of menopause. ISL has been also shown to have anti-tumor properties in a number of cancer cell backgrounds. However, the effects of ISL on normal cells are less well known and virtually unstudied in the context of the pituitary gland. We have established a pituitary explant culture model to screen chemical agents for gene expression changes within the pituitary gland during a period of active proliferation and differentiation. Using this whole-organ culture system we found ISL to be weakly estrogenic based on its ability to induce Cckar mRNA expression, an estrogen receptor (ER) mediated gene. Using a range of ISL from 200 nM to 200 μM, we discovered that ISL promoted cell proliferation at a low concentration, yet potently inhibited proliferation at the highest concentration. ICI 182,780 failed to antagonize ISL's repression of pituitary cell proliferation, indicating the effect is independent of ER signaling. Coincident with a decrease in proliferating cells, we observed down-regulation of transcript for cyclin D2 and E2 and a strong induction of mRNA and protein for the cyclin dependent kinase inhibitor Cdkn1a (p21). Importantly, high dose ISL did not alter the balance of progenitor vs. differentiated cell types within the pituitary explants and they seemed otherwise healthy; however, TUNEL staining revealed an increase in apoptotic cell death in ISL treated cultures. Our results merit further examination of ISL as an anti-tumor agent in the pituitary gland. - Highlights: • Isoliquiritigenin possesses weak estrogenic activity based on induction of Cckar. • ISL can be anti-proliferative in pituitary explants without altering cell lineages. • Anti-proliferative behavior of ISL is not estrogen receptor mediated. • ISL induces p21 expression leading to cell cycle arrest and apoptosis.

  13. A supermolecular curcumin for enhanced antiproliferative and proapoptotic activities: molecular characteristics, computer modeling and in vivo pharmacokinetics

    International Nuclear Information System (INIS)

    Tan Qunyou; Wu Jianyong; Li Yi; Zhang Jingqing; Mei Hu; Zhao Chunjing

    2013-01-01

    The supermolecular curcumin (SMCCM) exhibiting remarkably improved solubility and release characteristics was fabricated to increase the oral bioavailability in rat as well as the antiproliferative and proapoptotic activities of curcumin (CCM) against human lung adenocarcinoma cell A549. SMCCM was characterized by differential scanning calorimetry, Fourier transform infrared spectroscopy, morphology and structure, aqueous solubility, and release behavior in vitro. Computer modeling of the supermolecular structure was performed. The pharmacokinetics, antiproliferative and proapoptotic activities of SMCCM were evaluated. The mechanisms by which SMCCM inhibited proliferation and induced apoptosis were identified. The formation of SMCCM was testified and the supermolecular structure was studied by a computer modeling technique. Compared to free CCM, SMCCM with much higher aqueous solubility exhibited obviously enhanced release and more favorable pharmacokinetic profiles, and, furthermore, SMCCM showed higher anticancer efficacy, enhanced induction of G2/M-phase arrest and apoptosis in A549 cells, which might be involved with the increases in reactive oxygen species production and intracellular Ca 2+ accumulation, and a decrease in mitochondrial membrane potential. SMCCM remarkably enhanced not only the oral bioavailability but also the antiproliferative and proapoptotic activities of CCM along with improved solubility and release characteristics of CCM. (paper)

  14. A supermolecular curcumin for enhanced antiproliferative and proapoptotic activities: molecular characteristics, computer modeling and in vivo pharmacokinetics

    Science.gov (United States)

    Tan, Qunyou; Wu, Jianyong; Li, Yi; Mei, Hu; Zhao, Chunjing; Zhang, Jingqing

    2013-01-01

    The supermolecular curcumin (SMCCM) exhibiting remarkably improved solubility and release characteristics was fabricated to increase the oral bioavailability in rat as well as the antiproliferative and proapoptotic activities of curcumin (CCM) against human lung adenocarcinoma cell A549. SMCCM was characterized by differential scanning calorimetry, Fourier transform infrared spectroscopy, morphology and structure, aqueous solubility, and release behavior in vitro. Computer modeling of the supermolecular structure was performed. The pharmacokinetics, antiproliferative and proapoptotic activities of SMCCM were evaluated. The mechanisms by which SMCCM inhibited proliferation and induced apoptosis were identified. The formation of SMCCM was testified and the supermolecular structure was studied by a computer modeling technique. Compared to free CCM, SMCCM with much higher aqueous solubility exhibited obviously enhanced release and more favorable pharmacokinetic profiles, and, furthermore, SMCCM showed higher anticancer efficacy, enhanced induction of G2/M-phase arrest and apoptosis in A549 cells, which might be involved with the increases in reactive oxygen species production and intracellular Ca2+ accumulation, and a decrease in mitochondrial membrane potential. SMCCM remarkably enhanced not only the oral bioavailability but also the antiproliferative and proapoptotic activities of CCM along with improved solubility and release characteristics of CCM.

  15. Thermodynamic, Anticoagulant, and Antiproliferative Properties of Thrombin Binding Aptamer Containing Novel UNA Derivative

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    Weronika Kotkowiak

    2018-03-01

    Full Text Available Thrombin is a serine protease that plays a crucial role in hemostasis, fibrinolysis, cell proliferation, and migration. Thrombin binding aptamer (TBA is able to inhibit the activity of thrombin molecule via binding to its exosite I. This 15-nt DNA oligonucleotide forms an intramolecular, antiparallel G-quadruplex structure with a chair-like conformation. In this paper, we report on our investigations on the influence of certain modified nucleotide residues on thermodynamic stability, folding topology, and biological properties of TBA variants. In particular, the effect of single incorporation of a novel 4-thiouracil derivative of unlocked nucleic acid (UNA, as well as single incorporation of 4-thiouridine and all four canonical UNAs, was evaluated. The studies presented herein have shown that 4-thiouridine in RNA and UNA series, as well as all four canonical UNAs, can efficiently modulate G-quadruplex thermodynamic and biological stability, and that the effect is strongly position dependent. Interestingly, TBA variants containing the modified nucleotide residues are characterized by unchanged folding topology. Thrombin time assay revealed that incorporation of certain UNA residues may improve G-quadruplex anticoagulant properties. Noteworthy, some TBA variants, characterized by decreased ability to inhibit thrombin activity, possess significant antiproliferative properties reducing the viability of the HeLa cell line even by 95% at 10 μM concentration.

  16. Stevia rebaudiana ethanolic extract exerts better antioxidant properties and antiproliferative effects in tumour cells than its diterpene glycoside stevioside.

    Science.gov (United States)

    López, Víctor; Pérez, Sergio; Vinuesa, Arturo; Zorzetto, Christian; Abian, Olga

    2016-04-01

    Steviol glycosides are currently being used as natural sweeteners by the food industry and Stevia rebaudiana has long been used as a sweet plant in South America for patients suffering from diabetes. In this study, a Stevia rebaudiana ethanolic extract (SREE) was prepared, analysed and tested for antioxidant activity in terms of free radical scavenging properties and antiproliferative effects in cervix (HeLa), pancreatic (MiaPaCa-2) and colonic (HCT116) cancer cells. The antiproliferative mechanism was confirmed by testing the effects on cyclin D1-CDK4. Bioassays were also performed for the diterpene glycoside stevioside. Our results demonstrate that the extract acts as an antioxidant being able to scavenge free radicals, but this activity was not due to stevioside. The extract also induced cell death in the three cell lines, being more active against cervix cancer cells (HeLa); however, the concentration of stevioside needed to produce antiproliferative effects was higher than the amount of steviol glycosides found in a lower dose of extract inducing cell death. In addition, the extract clearly inhibited CDK4 whereas stevioside did not, concluding that the antiproliferative activity of stevia may be due to inhibition of cyclin-dependent kinases performed by other compounds of the extract.

  17. Azithromycin Synergistically Enhances Anti-Proliferative Activity of Vincristine in Cervical and Gastric Cancer Cells

    International Nuclear Information System (INIS)

    Zhou, Xuezhang; Zhang, Yuyan; Li, Yong; Hao, Xiujing; Liu, Xiaoming; Wang, Yujiong

    2012-01-01

    In this study, the anti-proliferative and anticancer activity of azithromycin (AZM) was examined. In the presence of AZM, cell growth was inhibited more effectively in Hela and SGC-7901 cancer cells, relative to transformed BHK-21 cells. The respective 50% inhibition of cell growth (IC 50 ) values for Hela, SGC-7901 and BHK-21 were 15.66, 26.05 and 91.00 µg/mL at 72 h post incubation, indicative of a selective cytotoxicity against cancer cells. Cell apoptosis analysis using Hoechst nuclear staining and annexin V-FITC binding assay further demonstrated that AZM was capable of inducing apoptosis in both cancer cells and transformed cells. The apoptosis induced by AZM was partly through a caspase-dependent mechanism with an up-regulation of apoptotic protein cleavage PARP and caspase-3 products, as well as a down-regulation of anti-apoptotic proteins, Mcl-1, bcl-2 and bcl-X1. More importantly, a combination of AZM and a low dose of the common anti-cancer chemotherapeutic agent vincristine (VCR), produced a selectively synergistic effect on apoptosis of Hela and SGC-7901 cells, but not BHK-21 cells. In the presence of 12.50 μg/mL of VCR, the respective IC 50 values of Hela, SGC-7901 and BHK-21 cells to AZM were reduced to 9.47 µg/mL, 8.43 µg/mL and 40.15 µg/mL at 72 h after the incubation, suggesting that the cytotoxicity of AZM had a selective anti-cancer effect on cancer over transformed cells in vitro. These results imply that AZM may be a potential anticancer agent for use in chemotherapy regimens, and it may minimize side effects via reduction of dosage and enhancing the effectiveness common chemotherapeutic drugs

  18. PDE5 Inhibitors-Loaded Nanovesicles: Physico-Chemical Properties and In Vitro Antiproliferative Activity

    Directory of Open Access Journals (Sweden)

    Roberta F. De Rose

    2016-05-01

    Full Text Available Novel therapeutic approaches are required for the less differentiated thyroid cancers which are non-responsive to the current treatment. In this study we tested an innovative formulation of nanoliposomes containing sildenafil citrate or tadalafil, phosphodiesterase-5 inhibitors, on two human thyroid cancer cell lines (TPC-1 and BCPAP. Nanoliposomes were prepared by the thin layer evaporation and extrusion methods, solubilizing the hydrophilic compound sildenafil citrate in the aqueous phase during the hydration step and dissolving the lipophilic tadalafil in the organic phase. Nanoliposomes, made up of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine monohydrate (DPPC, cholesterol, and N-(carbonyl-methoxypolyethylene glycol-2000-1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE-mPEG2000 (6:3:1 molar ratio, were characterized by a mean diameter of ~100 nm, a very low polydispersity index (~0.1 and a negative surface charge. The drugs did not influence the physico-chemical properties of the systems and were efficiently retained in the colloidal structure. By using cell count and MTT assay, we found a significant reduction of the viability in both cell lines following 24 h treatment with both nanoliposomal-encapsulated drugs, notably greater than the effect of the free drugs. Our findings demonstrate that nanoliposomes increase the antiproliferative activity of phosphodiesterase-5 inhibitors, providing a useful novel formulation for the treatment of thyroid carcinoma.

  19. Daphne striata Tratt. and D. mezereum L.: a study of anti-proliferative activity towards human cancer cells and antioxidant properties.

    Science.gov (United States)

    Tundis, Rosa; Loizzo, Monica R; Bonesi, Marco; Peruzzi, Lorenzo; Efferth, Thomas

    2018-02-12

    In this study, we investigated for the first time the anti-proliferative and antioxidant properties of D. mezereum and D. striata. The aerial parts were extracted by maceration with n-hexane, dichloromethane, and methanol. MPLC, GC, and GC-MS were used for the phytochemical study. The anti-proliferative activity was tested against MCF-7, A549, LNCaP, ACHN, and C32 cancer human cells. The antioxidant activity was measured by employing β-carotene bleaching, ABTS, DPPH, and FRAP tests. The Relative Antioxidant Capacity Index (RACI) was applied from the perspective of statistics. D. mezereum dichloromethane extract showed a remarkable anti-proliferative with an IC 50 of 6.08 μg/mL against LNCaP cells. Experimental data indicate that Daphne species have interesting anti-proliferative and antioxidant properties that deserve more investigations to develop novel antineoplastic drugs.

  20. Phytochemical properties and anti-proliferative activity of Olea europaea L. leaf extracts against pancreatic cancer cells.

    Science.gov (United States)

    Goldsmith, Chloe D; Vuong, Quan V; Sadeqzadeh, Elham; Stathopoulos, Costas E; Roach, Paul D; Scarlett, Christopher J

    2015-07-17

    Olea europaea L. leaves are an agricultural waste product with a high concentration of phenolic compounds; especially oleuropein. Oleuropein has been shown to exhibit anti-proliferative activity against a number of cancer types. However, they have not been tested against pancreatic cancer, the fifth leading cause of cancer related death in Western countries. Therefore, water, 50% ethanol and 50% methanol extracts of Corregiola and Frantoio variety Olea europaea L. leaves were investigated for their total phenolic compounds, total flavonoids and oleuropein content, antioxidant capacity and anti-proliferative activity against MiaPaCa-2 pancreatic cancer cells. The extracts only had slight differences in their phytochemical properties, and at 100 and 200 μg/mL, all decreased the viability of the pancreatic cancer cells relative to controls. At 50 μg/mL, the water extract from the Corregiola leaves exhibited the highest anti-proliferative activity with the effect possibly due to early eluting HPLC peaks. For this reason, olive leaf extracts warrant further investigation into their potential anti-pancreatic cancer benefits.

  1. Recycling antimalarial leads for cancer: Antiproliferative properties of N-cinnamoyl chloroquine analogues

    OpenAIRE

    Bianca C Perez; Iva Fernandes; Nuno Mateus; Catia Teixeira; Paula Gomes

    2013-01-01

    Cinnamic acids and quinolines are known as useful scaffolds in the discovery of antitumor agents. Therefore, N-cinnamoylated analogues of chloroquine, recently reported as potent dual-action antimalarials, were evaluated against three different cancer cell lines: MKN-28, Caco-2, and MCF-7. All compounds display anti-proliferative activity in the micromolar range against the three cell lines tested, and most of them were more active than their parent drug, chloroquine, against all cell lines t...

  2. Antiproliferative and Antioxidant Properties of Anthocyanin Rich Extracts from Blueberry and Blackcurrant Juice

    Directory of Open Access Journals (Sweden)

    Zoriţa Diaconeasa

    2015-01-01

    Full Text Available The present study was aimed at evaluating the antiproliferative potential of anthocyanin-rich fractions (ARFs obtained from two commercially available juices (blueberry and blackcurrant juices on three tumor cell lines; B16F10 (murine melanoma, A2780 (ovarian cancer and HeLa (cervical cancer. Individual anthocyanin determination, identification and quantification were done using HPLC-MS. Antioxidant activity of the juices was determined through different mechanism methods such as DPPH and ORAC. For biological testing, the juices were purified through C18 cartridges in order to obtain fractions rich in anthocyanins. The major anthocyanins identified were glycosylated cyanidin derivatives. The antiproliferative activity of the fractions was tested using the MTT assay. The antiproliferative potential of ARF was found to be associated with those bioactive molecules, anthocyanins due to their antioxidant potential. The results obtained indicated that both blueberry and blackcurrants are rich sources of antioxidants including anthocyanins and therefore these fruits are highly recommended for daily consumption to prevent numerous degenerative diseases.

  3. Enhanced anti-proliferative efficacy of epothilone B loaded with Escherichia coli Nissle 1917 bacterial ghosts on the HeLa cells by mitochondrial pathway of apoptosis.

    Science.gov (United States)

    Zhu, Wenxing; Hao, Lujiang; Liu, Xinli; Orlando, Borrás-Hidalgo; Zhang, Yuyu

    2018-03-20

    Epothilones constitute a new class of microtubule-stabilizing anti-cancer agents with promising preclinical and clinical activity. However, its systemic application still causes some toxic side effects. To reduce these undesired effects, advanced drug delivery systems based on cell targeting carriers are needed currently. In this study, the high quality bacterial ghosts of the probiotic Escherichia coli Nissle 1917 (EcN) were prepared in a large scale and retained fully intact surface structures for specific attachment to mammalian cells. The EcN ghosts could be efficiently loaded with the low hydrophilic drug Epothilone B (Epo B) and the maximal load efficiency was approximately 2.5% (w/w). Cytotoxicity assays revealed that Epo B-ghosts exhibited enhanced anti-proliferative properties on the HeLa cells. The Epo B associated with EcN ghosts was more cytotoxic at least 10 times than the free Epo B at the same concentrations. Apoptosis assays showed that both Epo B-ghosts and free Epo B induced time course-dependent apoptosis and necrosis in HeLa cells, respectively. While the former induced more apoptosis and necrosis than the latter. Furthermore, the cytochrome C release and the activation of caspase-3 were more remarkable after treatment with the Epo B-ghosts compared to the free Epo B, which implied that Epo B-ghosts might more effectively induce the apoptosis mediated by mitochondrial pathway in HeLa cells. Therefore, the higher anti-proliferative effects of the Epo B-ghosts on the HeLa cells were mediated by mitochondrial pathway of apoptosis. The EcN ghosts may provide a useful drug delivery carrier for drug candidates in cancer therapy.

  4. Antibacterial, antioxidant and anti-proliferative properties and zinc content of five south Portugal herbs.

    Science.gov (United States)

    Nunes, Ricardo; Pasko, Pawel; Tyszka-Czochara, Malgorzata; Szewczyk, Agnieszka; Szlosarczyk, Marek; Carvalho, Isabel S

    2017-12-01

    Crataegus monogyna L. (Rosaceae) (CM), Equisetum telmateia L. (Equisataceae) (ET), Geranium purpureum Vil. (Geraniaceae) (GP), Mentha suaveolens Ehrh. (Lamiaceae) (MS), and Lavandula stoechas L. spp. luisieri (Lamiaceae) (LS) are all medicinal. To evaluate the antioxidant, antiproliferative and antimicrobial activities of plant extracts and quantify individual phenolics and zinc. Aerial part extracts were prepared with water (W), ethanol (E) and an 80% mixture (80EW). Antioxidant activity was measured with TAA, FRAP and RP methods. Phenolics were quantified with a HPLC. Zinc was quantified using voltammetry. Antibacterial activity (after 48 h) was tested using Enterococcus faecalis, Bacillus cereus, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Listeria monocytogenes. Antiproliferative activity (after 24 h) was tested using HEP G2 cells and fibroblasts. Solvents influenced results; the best were E and 80EW. GP had the highest antioxidant activity (TAA and FRAP of 536.90 mg AAE/g dw and 783.48 mg TE/g dw, respectively). CM had the highest zinc concentration (37.21 mg/kg) and phenolic variety, with neochlorogenic acid as the most abundant (92.91 mg/100 g dw). LS was rich in rosmarinic acid (301.71 mg/100 g dw). GP and LS inhibited the most microorganisms: B. cereus, E. coli and S. aureus. GP also inhibited E. faecalis. CM had the lowest MIC: 5830 μg/mL. The antibacterial activity is explained by the phenolics present. LS and CM showed the most significant anti-proliferative activity, which is explained by their zinc content. The most promising plants for further studies are CM, LS and GP.

  5. Recycling antimalarial leads for cancer: Antiproliferative properties of N-cinnamoyl chloroquine analogues.

    Science.gov (United States)

    Pérez, Bianca C; Fernandes, Iva; Mateus, Nuno; Teixeira, Cátia; Gomes, Paula

    2013-12-15

    Cinnamic acids and quinolines are known as useful scaffolds in the discovery of antitumor agents. Therefore, N-cinnamoylated analogues of chloroquine, recently reported as potent dual-action antimalarials, were evaluated against three different cancer cell lines: MKN-28, Caco-2, and MCF-7. All compounds display anti-proliferative activity in the micromolar range against the three cell lines tested, and most of them were more active than their parent drug, chloroquine, against all cell lines tested. Hence, N-cinnamoyl-chloroquine analogues are a good start towards development of affordable antitumor leads. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Enhancement of antiproliferative activity of interferons by RNA interference-mediated silencing of SOCS gene expression in tumor cells.

    Science.gov (United States)

    Takahashi, Yuki; Kaneda, Haruka; Takasuka, Nana; Hattori, Kayoko; Nishikawa, Makiya; Watanabe, Yoshihiko; Takakura, Yoshinobu

    2008-08-01

    The suppressor of cytokine signaling (SOCS) proteins, negative regulators of interferon (IFN)-induced signaling pathways, is involved in IFN resistance of tumor cells. To improve the growth inhibitory effect of IFN-beta and IFN-gamma on a murine melanoma cell line, B16-BL6, and a murine colon carcinoma cell line, Colon26 cells, SOCS-1 and SOCS-3 gene expression in tumor cells was downregulated by transfection of plasmid DNA expressing short hairpin RNA targeting one of these genes (pshSOCS-1 and pshSOCS-3, respectively). Transfection of pshSOCS-1 significantly increased the antiproliferative effect of IFN-gamma on B16-BL6 cells. However, any other combinations of plasmids and IFN had little effect on the growth of B16-BL6 cells. In addition, transfection of pshSOCS-1 and pshSOCS-3 produced little improvement in the effect of IFN on Colon26 cells. To understand the mechanism underlining these findings, the level of SOCS gene expression was measured by real time polymerase chain reaction. Addition of IFN-gamma greatly increased the SOCS-1 mRNA expression in B16-BL6 cells. Taking into account the synergistic effect of pshSOCS-1 and IFN-gamma on the growth of B16-BL6 cells, these findings suggest that IFN-gamma-induced high SOCS-1 gene expression in B16-BL6 cells significantly interferes with the antiproliferative effect of IFN-gamma. These results indicate that silencing SOCS gene expression can be an effective strategy to enhance the antitumor effect of IFN under conditions in which the SOCS gene expression is upregulated by IFN.

  7. Variability in Saponin Content, Cancer Antiproliferative Activity and Physicochemical Properties of Concentrated Agave Sap.

    Science.gov (United States)

    Santos-Zea, Liliana; Rosas-Pérez, Aratza Mireya; Leal-Díaz, Ana María; Gutiérrez-Uribe, Janet A

    2016-08-01

    Concentrated agave sap (CAS) has gained popularity as an unrefined sweetener. It is obtained by boiling "aguamiel" that contains phytochemicals with diverse bioactivities. Saponins have been the most widely studied agave phytochemicals due to their cancer antiproliferative effect but their concentration may vary due to maturity of the agave plant and collection site. In this study, 18 CAS samples produced in different states of Mexico were analyzed using multivariate methods to determine which physicochemical or phytochemical parameters were responsible for variation. Additionally, extracts with different saponin profiles were tested to determine possible correlations with antiproliferative activity. Total soluble solids, pH, and water activity were similar to those reported for other agave sweeteners. Antioxidant capacity of samples was correlated to browning index. Eleven steroidal saponins were found in CAS samples and they were the main source of variability. Magueyoside B, a kammogenin tetraglycoside, was the most abundant saponin in all samples. With respect to bioactivity, multivariate analysis indicated that magueyoside B and a gentrogenin tetraglycoside were compounds strongly related with bioactivity. CAS from Hidalgo, Puebla, and Veracruz had higher concentration of magueyoside B than from the other kamogenin tetraglycoside found in the samples from other Mexican states. These results could be used as a first approach to characterize and standardize CAS to validate the potential health benefits derived from its consumption. © 2016 Institute of Food Technologists®

  8. The nontoxic natural compound Curcumin exerts anti-proliferative, anti-migratory, and anti-invasive properties against malignant gliomas

    International Nuclear Information System (INIS)

    Senft, Christian; Polacin, Margareth; Priester, Maike; Seifert, Volker; Kögel, Donat; Weissenberger, Jakob

    2010-01-01

    New drugs are constantly sought after to improve the survival of patients with malignant gliomas. The ideal substance would selectively target tumor cells without eliciting toxic side effects. Here, we report on the anti-proliferative, anti-migratory, and anti-invasive properties of the natural, nontoxic compound Curcumin observed in five human glioblastoma (GBM) cell lines in vitro. We used monolayer wound healing assays, modified Boyden chamber trans-well assays, and cell growth assays to quantify cell migration, invasion, and proliferation in the absence or presence of Curcumin at various concentrations. Levels of the transcription factor phospho-STAT3, a potential target of Curcumin, were determined by sandwich-ELISA. Subsequent effects on transcription of genes regulating the cell cycle were analyzed by quantitative real-time PCR. Effects on apoptosis were determined by caspase assays. Curcumin potently inhibited GBM cell proliferation as well as migration and invasion in all cell lines contingent on dose. Simultaneously, levels of the biologically active phospho-STAT3 were decreased and correlated with reduced transcription of the cell cycle regulating gene c-Myc and proliferation marking Ki-67, pointing to a potential mechanism by which Curcumin slows tumor growth. Curcumin is part of the diet of millions of people every day and is without known toxic side effects. Our data show that Curcumin bears anti-proliferative, anti-migratory, and anti-invasive properties against GBM cells in vitro. These results warrant further in vivo analyses and indicate a potential role of Curcumin in the treatment of malignant gliomas

  9. Purification, structural characterization and antiproliferative properties of chondroitin sulfate/dermatan sulfate from tunisian fish skins.

    Science.gov (United States)

    Krichen, Fatma; Volpi, Nicola; Sila, Assaâd; Maccari, Francesca; Mantovani, Veronica; Galeotti, Fabio; Ellouz-Chaabouni, Semia; Bougatef, Ali

    2017-02-01

    Chondroitin sulfate/dermatan sulfate GAGs were extracted and purified from the skins of grey triggerfish (GTSG) and smooth hound (SHSG). The disaccharide composition produced by chondroitinase ABC treatment showed the presence of nonsulfated disaccharide, monosulfated disaccharides ΔDi6S and ΔDi4S, and disulfated disaccharides in different percentages. In particular, the nonsulfated disaccharide ΔDi0S of GTSG and SHSG were 3.5% and 5.5%, respectively, while monosulfated disaccharides ΔDi6S and ΔDi4S were evaluated to be 18.2%, 59% and 14.6%, 47.0%, respectively. Capillary elecrophoresis analysis of GTSG and SHSG contained 99.2% and 95.4% of chondroitin sulfate/dermatan sulfate, respectively. PAGE analysis showed a GTSG and SHSG having molecular masses with average values of 41.72KDa and 23.8KDa, respectively. HCT116 cell proliferation was inhibited (p<0.05) by 70.6% and 72.65% at 200μg/mL of GTSG and SHSG respectively. Both GTSG and SHSG demonstrated promising antiproliferative potential, which may be used as a novel, effective agent. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. The use of chitosan-dextran gel shows anti-inflammatory, antibiofilm, and antiproliferative properties in fibroblast cell culture.

    Science.gov (United States)

    Paramasivan, Sathish; Jones, Damien; Baker, Leonie; Hanton, Lyall; Robinson, Simon; Wormald, Peter J; Tan, Lorwai

    2014-01-01

    Chitosan-dextran gel has been used as an antihemostatic agent and antiadhesive agent after endoscopic sinus surgery. Because Staphylococcus aureus biofilms have been implicated in recalcitrant chronic rhinosinusitis, this study aimed to further investigate the (i) anti-inflammatory, (ii) bacterial biofilm inhibition, (iii) antiproliferative effects, and (iv) wound-healing properties of chitosan and chitosan-dextran gel. Fibroblasts were isolated from human nasal tissue and were used to determine the effects of chitosan and chitosan-dextran gel on (i) cell proliferation, (ii) wound healing, (iii) inflammation in fibroblast cultures challenged with superantigens S. aureus enterotoxin B (SEB) and toxic shock syndrome toxin (TSST), and (iv) on S. aureus biofilms. Chitosan was highly effective at reducing IL-8 expression after TSST and SEB challenge. Chitosan was also effective at reducing IL-8 expression of nonchallenged fibroblasts showing its anti-inflammatory effects on fibroblasts in a diseased state. Chitosan-dextran gel showed strong antibiofilm properties at 50% (v/v) concentration in vitro. Dextran, on its own, showed antibiofilm properties at 1.25% (w/v) concentration. Chitosan, on its own, reduced proliferation of fibroblasts to 82% of control proliferation and chitosan-dextran gel reduced proliferation of the fibroblasts to 0.04% of control proliferation. Relative to the no treatment controls, chitosan-dextran gel significantly delayed the wound-healing rate over the first 48 hours of the experiment. Chitosan-dextran gel reduced fibroblast proliferation and wound-healing time, showing a possible mechanism of reducing adhesions in the postsurgical period. Chitosan reduced IL-8 levels, showing its anti-inflammatory properties. Chitosan-dextran gel and dextran treatment showed antibiofilm properties in our model.

  11. Helleborus purpurascens—Amino Acid and Peptide Analysis Linked to the Chemical and Antiproliferative Properties of the Extracted Compounds

    Directory of Open Access Journals (Sweden)

    Adina-Elena Segneanu

    2015-12-01

    Full Text Available There is a strong drive worldwide to discover and exploit the therapeutic potential of a large variety of plants. In this work, an alcoholic extract of Helleborus purpurascens (family Ranunculaceae was investigated for the identification of amino acids and peptides with putative antiproliferative effects. In our work, a separation strategy was developed using solvents of different polarity in order to obtain active compounds. Biochemical components were characterized through spectroscopic (mass spectroscopy and chromatographic techniques (RP-HPLC and GC-MS. The biological activity of the obtained fractions was investigated in terms of their antiproliferative effects on HeLa cells. Through this study, we report an efficient separation of bioactive compounds (amino acids and peptides from a plant extract dependent on solvent polarity, affording fractions with unaffected antiproliferative activities. Moreover, the two biologically tested fractions exerted a major antiproliferative effect, thereby suggesting potential anticancer therapeutic activity.

  12. Helleborus purpurascens-Amino Acid and Peptide Analysis Linked to the Chemical and Antiproliferative Properties of the Extracted Compounds.

    Science.gov (United States)

    Segneanu, Adina-Elena; Grozescu, Ioan; Cziple, Florentina; Berki, Daniel; Damian, Daniel; Niculite, Cristina Mariana; Florea, Alexandru; Leabu, Mircea

    2015-12-11

    There is a strong drive worldwide to discover and exploit the therapeutic potential of a large variety of plants. In this work, an alcoholic extract of Helleborus purpurascens (family Ranunculaceae) was investigated for the identification of amino acids and peptides with putative antiproliferative effects. In our work, a separation strategy was developed using solvents of different polarity in order to obtain active compounds. Biochemical components were characterized through spectroscopic (mass spectroscopy) and chromatographic techniques (RP-HPLC and GC-MS). The biological activity of the obtained fractions was investigated in terms of their antiproliferative effects on HeLa cells. Through this study, we report an efficient separation of bioactive compounds (amino acids and peptides) from a plant extract dependent on solvent polarity, affording fractions with unaffected antiproliferative activities. Moreover, the two biologically tested fractions exerted a major antiproliferative effect, thereby suggesting potential anticancer therapeutic activity.

  13. AICAR Antiproliferative Properties Involve the AMPK-Independent Activation of the Tumor Suppressors LATS 1 and 2.

    Science.gov (United States)

    Philippe, Chloé; Pinson, Benoît; Dompierre, Jim; Pantesco, Véronique; Viollet, Benoît; Daignan-Fornier, Bertrand; Moenner, Michel

    2018-06-01

    AICAR (Acadesine) is a pharmacological precursor of purine nucleotide biosynthesis with anti-tumoral properties. Although recognized as an AMP mimetic activator of the protein kinase AMPK, the AICAR monophosphate derivative ZMP was also shown to mediate AMPK-independent effects. In order to unveil these AMPK-independent functions, we performed a transcriptomic analysis in AMPKα1/α2 double knockout murine embryonic cells. Kinetic analysis of the cellular response to AICAR revealed the up-regulation of the large tumor suppressor kinases (Lats) 1 and 2 transcripts, followed by the repression of numerous genes downstream of the transcriptional regulators Yap1 and Taz. This transcriptional signature, together with the observation of increased levels in phosphorylation of Lats1 and Yap1 proteins, suggested that the Hippo signaling pathway was activated by AICAR. This effect was observed in both fibroblasts and epithelial cells. Knockdown of Lats1/2 prevented the cytoplasmic delocalization of Yap1/Taz proteins in response to AICAR and conferred a higher resistance to the drug. These results indicate that activation of the most downstream steps of the Hippo cascade participates to the antiproliferative effects of AICAR. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  14. Phytochemical Constituents, Antioxidant and Antiproliferative Properties of a Liverwort, Lepidozia borneensis Stephani from Mount Kinabalu, Sabah, Malaysia

    Directory of Open Access Journals (Sweden)

    Mohd Fadzelly Abu Bakar

    2015-01-01

    Full Text Available The study aimed to investigate the phytochemical contents, antioxidant and antiproliferative activity of 80% methanol extract of Lepidozia borneensis. The total phenolic and total flavonoid contents were analysed using Folin-Ciocalteu and aluminium chloride colorimetric methods. Antioxidant properties were evaluated by using FRAP, ABTS, and DPPH assays while the effects of L. borneensis on the proliferation of MCF-7 cell line were evaluated by using MTT assay. The results showed that the total phenolic and flavonoid contents were 12.42 ± 0.47 mg GAE/g and 9.36 ± 1.29 mg CE/g, respectively. The GC-MS analysis revealed the presence of at least 35 compounds. The extract was found to induce cytotoxicity against MCF-7 cell line with IC50 value of 47.33 ± 7.37 µg/mL. Cell cycle analysis showed that the extract induced significant arrest at G0/G1 at 24 hours of treatment. After 72 hours of treatment, the proportion of cells in G0/G1 and G2-M phases had decreased significantly as compared to their control. Apoptosis occurred during the first 24 hours and significantly increased to 30.8% after 72 hours of treatment. No activation of caspase 3 was observed. These findings suggest that L. borneensis extract has the potential as natural antioxidant and anticancer agents.

  15. Synthesis and antiproliferative properties of new hydrophilic esters of triterpenic acids.

    Science.gov (United States)

    Eignerova, Barbara; Tichy, Michal; Krasulova, Jana; Kvasnica, Miroslav; Rarova, Lucie; Christova, Romana; Urban, Milan; Bednarczyk-Cwynar, Barbara; Hajduch, Marian; Sarek, Jan

    2017-11-10

    To improve the properties of cytotoxic triterpenoid acids 1-5, a large set of hydrophilic esters was synthesized. We choose betulinic acid (1), dihydrobetulinic acid (2), 21-oxoacid 3 along with highly active des-E lupane acids 4 and 5 as a model set of compounds for esterification of which the properties needed to be improved. As ester moieties were used - methoxyethanol and 2-(2-methoxyethoxy)ethanol and glycolic unit (type a-d), pyrrolidinoethanol, piperidinoethanol and morpholinoethanol (type f-h), and monosaccharide groups (type i-l). As a result, 56 triterpenic esters (49 new compounds) were obtained and their cytotoxicity on four cancer cell lines and normal human fibroblasts was tested. All new compounds were fully soluble at all tested concentrations, which used to be a problem of the parent compounds 1 and 2. 16 compounds had IC 50  acids 1-5. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  16. Investigation of the Antiproliferative Properties of Natural Sesquiterpenes from Artemisia asiatica and Onopordum acanthium on HL-60 Cells in Vitro

    Directory of Open Access Journals (Sweden)

    Judit Molnár

    2016-02-01

    Full Text Available Plants and plant extracts play a crucial role in the research into novel antineoplastic agents. Four sesquiterpene lactones, artecanin (1, 3β-chloro-4α,10α-dihydroxy-1α,2α-epoxy-5α,7αH-guaia-11(13-en-12,6α-olide (2, iso-seco-tanapartholide 3-O-methyl ether (3 and 4β,15-dihydro-3-dehydrozaluzanin C (4, were isolated from two traditionally used Asteraceae species (Onopordum acanthium and Artemisia asiatica. When tested for antiproliferative action on HL-60 leukemia cells, these compounds exhibited reasonable IC50 values in the range 3.6–13.5 μM. Treatment with the tested compounds resulted in a cell cycle disturbance characterized by increases in the G1 and G2/M populations, while there was a decrease in the S phase. Additionally, 1–3 elicited increases in the hypodiploid (subG1 population. The compounds elicited concentration-dependent chromatin condensation and disruption of the membrane integrity, as revealed by Hoechst 33258–propidium staining. Treatment for 24 h resulted in significant increases in activity of caspases-3 and -9, indicating that the tested sesquiterpenes induced the mitochondrial pathway of apoptosis. The proapoptotic properties of the sesquiterpene lactones were additionally demonstrated withannexin V staining. Compounds 1 and 2 increased the Bax/Bcl-2 expression and decreased the expressions of CDK1 and cyclin B2, as determined at the mRNA level by means of RT-PCR. These experimental results indicate that sesquiterpene lactones may be regarded as potential starting structures for the development of novel anticancer agents.

  17. The IL-6 receptor super-antagonist Sant7 enhances antiproliferative and apoptotic effects induced by dexamethasone and zoledronic acid on multiple myeloma cells.

    Science.gov (United States)

    Tassone, Pierfrancesco; Galea, Eulalia; Forciniti, Samantha; Tagliaferri, Pierosandro; Venuta, Salvatore

    2002-10-01

    Interleukin-6 (IL-6) is the major growth and survival factor for multiple myeloma (MM), and has been shown to protect MM cells from apoptosis induced by a variety of agents. IL-6 receptor antagonists, which prevent the assembly of functional IL-6 receptor complexes, inhibit cell proliferation and induce apoptosis in MM cells. We have investigated whether the IL-6 receptor super-antagonist Sant7 might enhance the antiproliferative and apoptotic effects induced by the combination of dexamethasone (Dex) and zoledronic acid (Zln) on human MM cell lines and primary cells from MM patients. Here we show that each of these compounds individually induced detectable antiproliferative effects on MM cells. Sant7 significantly enhanced growth inhibition and apoptosis induced by Dex and Zln on both MM cell lines and primary MM cells. These results indicate that overcoming IL-6 mediated cell resistance by Sant7 potentiates the effect of glucocorticoides and bisphosphonates on MM cell growth and survival, providing a rationale for therapies including IL-6 antagonists in MM.

  18. Thermodynamic, Anticoagulant, and Antiproliferative Properties of Thrombin Binding Aptamer Containing Novel UNA Derivative

    DEFF Research Database (Denmark)

    Kotkowiak, Weronika; Lisowiec-Wachnicka, Jolanta; Grynda, Jakub

    2018-01-01

    Thrombin is a serine protease that plays a crucial role in hemostasis, fibrinolysis, cell proliferation, and migration. Thrombin binding aptamer (TBA) is able to inhibit the activity of thrombin molecule via binding to its exosite I. This 15-nt DNA oligonucleotide forms an intramolecular, antipar......Thrombin is a serine protease that plays a crucial role in hemostasis, fibrinolysis, cell proliferation, and migration. Thrombin binding aptamer (TBA) is able to inhibit the activity of thrombin molecule via binding to its exosite I. This 15-nt DNA oligonucleotide forms an intramolecular......, antiparallel G-quadruplex structure with a chair-like conformation. In this paper, we report on our investigations on the influence of certain modified nucleotide residues on thermodynamic stability, folding topology, and biological properties of TBA variants. In particular, the effect of single incorporation......-quadruplex thermodynamic and biological stability, and that the effect is strongly position dependent. Interestingly, TBA variants containing the modified nucleotide residues are characterized by unchanged folding topology. Thrombin time assay revealed that incorporation of certain UNA residues may improve G...

  19. Development of antiproliferative nanohybrid compound with controlled release property using ellagic acid as the active agent

    Directory of Open Access Journals (Sweden)

    Hussein MZ

    2011-07-01

    Full Text Available Mohd Zobir Hussein1,2, Samer Hasan Al Ali2, Zulkarnain Zainal2, Muhammad Nazrul Hakim31Advanced Materials and Nanotechnology Laboratory, Institute of Advanced Technology (ITMA, 2Department of Chemistry, Faculty of Science, 3Department of Biomedical Science, Faculty of Medicine and Health Science, Universiti Putra Malaysia, Selangor, MalaysiaAbstract: An ellagic acid (EA–zinc layered hydroxide (ZLH nanohybrid (EAN was synthesized under a nonaqueous environment using EA and zinc oxide (ZnO as the precursors. Powder X-ray diffraction showed that the basal spacing of the nanohybrid was 10.4 Å, resulting in the spatial orientation of EA molecules between the interlayers of 22.5° from z-axis with two negative charges at 8,8′ position of the molecules pointed toward the ZLH interlayers. FTIR study showed that the intercalated EA spectral feature is generally similar to that of EA, but with bands slightly shifted. This indicates that some chemical bonding of EA presence between the nanohybrid interlayers was slightly changed, due to the formation of host–guest interaction. The nanohybrid is of mesopores type with 58.8% drug loading and enhanced thermal stability. The release of the drug active, EA from the nanohybrid was found to be sustained and therefore has good potential to be used as a drug controlled-release formulation. In vitro bioassay study showed that the EAN has a mild effect on the hepatocytes cells, similar to its counterpart, free EA.Keywords: ellagic acid, nonaqueous solution, ZnO, zinc-layered hydroxide, viability test

  20. Metformin synergistically enhances antiproliferative effects of cisplatin and etoposide in NCI-H460 human lung cancer cells

    Directory of Open Access Journals (Sweden)

    Sarah Fernandes Teixeira

    2013-12-01

    Full Text Available OBJECTIVE: To test the effectiveness of combining conventional antineoplastic drugs (cisplatin and etoposide with metformin in the treatment of non-small cell lung cancer in the NCI-H460 cell line, in order to develop new therapeutic options with high efficacy and low toxicity.METHODS: We used the 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assay and calculated the combination index for the drugs studied.RESULTS: We found that the use of metformin as monotherapy reduced the metabolic viability of the cell line studied. Combining metformin with cisplatin or etoposide produced a synergistic effect and was more effective than was the use of cisplatin or etoposide as monotherapy.CONCLUSIONS: Metformin, due to its independent effects on liver kinase B1, had antiproliferative effects on the NCI-H460 cell line. When metformin was combined with cisplatin or etoposide, the cell death rate was even higher.

  1. Modification of the estrogenic properties of diphenols by the incorporation of ferrocene. Generation of antiproliferative effects in vitro.

    Science.gov (United States)

    Vessières, Anne; Top, Siden; Pigeon, Pascal; Hillard, Elizabeth; Boubeker, Leila; Spera, Daniela; Jaouen, Gérard

    2005-06-16

    We report here the synthesis and the strong and unexpected antiproliferative effect of the organometallic diphenolic compound 1,1-bis(4'-hydroxyphenyl)-2-ferrocenyl-but-1-ene (4) on both hormone-dependent (MCF7) and -independent (MDA-MB231) breast cancer cells (IC(50) = 0.7 and 0.6 microM). Surprisingly, 6 [1,2-bis(4'-hydroxyphenyl)-2-ferrocenyl-but-1-ene], the regioisomer of 4, shows only a modest effect on these cell lines. This pertinent organometallic modification seems to trigger an intracellular oxidation of the structurally favorable compound 4, leading to the generation of a potent cytotoxic compound.

  2. Ruthenium(III) Complexes of Heterocyclic Tridentate (ONN) Schiff Base: Synthesis, Characterization and its Biological Properties as an Antiradical and Antiproliferative Agent

    Science.gov (United States)

    Ejidike, Ikechukwu P.; Ajibade, Peter A.

    2016-01-01

    The current work reports the synthesis, spectroscopic studies, antiradical and antiproliferative properties of four ruthenium(III) complexes of heterocyclic tridentate Schiff base bearing a simple 2′,4′-dihydroxyacetophenone functionality and ethylenediamine as the bridging ligand with RCHO moiety. The reaction of the tridentate ligands with RuCl3·3H2O lead to the formation of neutral complexes of the type [Ru(L)Cl2(H2O)] (where L = tridentate NNO ligands). The compounds were characterized by elemental analysis, UV-vis, conductivity measurements, FTIR spectroscopy and confirmed the proposed octahedral geometry around the Ru ion. The Ru(III) compounds showed antiradical potentials against 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals, with DPPH scavenging capability in the order: [(PAEBOD)RuCl2] > [(BZEBOD)RuCl2] > [(MOABOD)RuCl2] > [Vit. C] > [rutin] > [(METBOD)RuCl2], and ABTS radical in the order: [(PAEBOD)RuCl2] < [(MOABOD)RuCl2] < [(BZEBOD)RuCl2] < [(METBOD)RuCl2]. Furthermore, in vitro anti-proliferative activity was investigated against three human cancer cell lines: renal cancer cell (TK-10), melanoma cancer cell (UACC-62) and breast cancer cell (MCF-7) by SRB assay. PMID:26742030

  3. Ruthenium(III Complexes of Heterocyclic Tridentate (ONN Schiff Base: Synthesis, Characterization and its Biological Properties as an Antiradical and Antiproliferative Agent

    Directory of Open Access Journals (Sweden)

    Ikechukwu P. Ejidike

    2016-01-01

    Full Text Available The current work reports the synthesis, spectroscopic studies, antiradical and antiproliferative properties of four ruthenium(III complexes of heterocyclic tridentate Schiff base bearing a simple 2′,4′-dihydroxyacetophenone functionality and ethylenediamine as the bridging ligand with RCHO moiety. The reaction of the tridentate ligands with RuCl3·3H2O lead to the formation of neutral complexes of the type [Ru(LCl2(H2O] (where L = tridentate NNO ligands. The compounds were characterized by elemental analysis, UV-vis, conductivity measurements, FTIR spectroscopy and confirmed the proposed octahedral geometry around the Ru ion. The Ru(III compounds showed antiradical potentials against 2,2-Diphenyl-1-Picrylhydrazyl (DPPH and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS radicals, with DPPH scavenging capability in the order: [(PAEBODRuCl2] > [(BZEBODRuCl2] > [(MOABODRuCl2] > [Vit. C] > [rutin] > [(METBODRuCl2], and ABTS radical in the order: [(PAEBODRuCl2] < [(MOABODRuCl2] < [(BZEBODRuCl2] < [(METBODRuCl2]. Furthermore, in vitro anti-proliferative activity was investigated against three human cancer cell lines: renal cancer cell (TK-10, melanoma cancer cell (UACC-62 and breast cancer cell (MCF-7 by SRB assay.

  4. The Budding Yeast “Saccharomyces cerevisiae” as a Drug Discovery Tool to Identify Plant-Derived Natural Products with Anti-Proliferative Properties

    Directory of Open Access Journals (Sweden)

    Bouchra Qaddouri

    2011-01-01

    Full Text Available The budding yeast Saccharomyces cerevisiae is a valuable system to study cell-cycle regulation, which is defective in cancer cells. Due to the highly conserved nature of the cell-cycle machinery between yeast and humans, yeast studies are directly relevant to anticancer-drug discovery. The budding yeast is also an excellent model system for identifying and studying antifungal compounds because of the functional conservation of fungal genes. Moreover, yeast studies have also contributed greatly to our understanding of the biological targets and modes of action of bioactive compounds. Understanding the mechanism of action of clinically relevant compounds is essential for the design of improved second-generation molecules. Here we describe our methodology for screening a library of plant-derived natural products in yeast in order to identify and characterize new compounds with anti-proliferative properties.

  5. Targeting EGFR/HER2 pathways enhances the antiproliferative effect of gemcitabine in biliary tract and gallbladder carcinomas

    International Nuclear Information System (INIS)

    Pignochino, Ymera; Bardelli, Alberto; Aglietta, Massimo; Leone, Francesco; Sarotto, Ivana; Peraldo-Neia, Caterina; Penachioni, Junia Y; Cavalloni, Giuliana; Migliardi, Giorgia; Casorzo, Laura; Chiorino, Giovanna; Risio, Mauro

    2010-01-01

    Advanced biliary tract carcinomas (BTCs) have poor prognosis and limited therapeutic options. Therefore, it is crucial to combine standard therapies with molecular targeting. In this study EGFR, HER2, and their molecular transducers were analysed in terms of mutations, amplifications and over-expression in a BTC case series. Furthermore, we tested the efficacy of drugs targeting these molecules, as single agents or in combination with gemcitabine, the standard therapeutic agent against BTC. Immunohistochemistry, FISH and mutational analysis were performed on 49 BTC samples of intrahepatic (ICCs), extrahepatic (ECCs), and gallbladder (GBCs) origin. The effect on cell proliferation of different EGFR/HER2 pathway inhibitors as single agents or in combination with gemcitabine was investigated on BTC cell lines. Western blot analyses were performed to investigate molecular mechanisms of targeted drugs. EGFR is expressed in 100% of ICCs, 52.6% of ECCs, and in 38.5% of GBCs. P-MAPK and p-Akt are highly expressed in ICCs (>58% of samples), and to a lower extent in ECCs and GBCs (<46%), indicating EGFR pathway activation. HER2 is overexpressed in 10% of GBCs (with genomic amplification), and 26.3% of ECCs (half of which has genomic amplification). EGFR or its signal transducers are mutated in 26.5% of cases: 4 samples bear mutations of PI3K (8.2%), 3 cases (6.1%) in K-RAS, 4 (8.2%) in B-RAF, and 2 cases (4.1%) in PTEN, but no loss of PTEN expression is detected. EGI-1 cell line is highly sensitive to gemcitabine, TFK1 and TGBC1-TKB cell lines are responsive and HuH28 cell line is resistant. In EGI-1 cells, combination with gefitinib further increases the antiproliferative effect of gemcitabine. In TFK1 and TGBC1-TKB cells, the efficacy of gemcitabine is increased with addiction of sorafenib and everolimus. In TGBC1-TKB cells, lapatinib also has a synergic effect with gemcitabine. HuH28 becomes responsive if treated in combination with erlotinib. Moreover, HuH28 cells are

  6. Anti-proliferative, Cytotoxic and NF-ĸB Inhibitory Properties of Spiro(Lactone-Cyclohexanone) Compounds in Human Leukemia.

    Science.gov (United States)

    Bouhenna, Mustapha M; Orlikova, Barbora; Talhi, Oualid; Schram, Ben; Pinto, Diana C G A; Taibi, Nadia; Bachari, Khaldoun; Diederich, Marc; Silva, Artur M S; Mameri, Nabil

    2017-09-01

    NF-ĸB affects most aspects of cellular physiology. Deregulation of NF-ĸB signaling is associated with inflammatory diseases and cancer. In this study, we evaluated the cytotoxic and NF-ĸB inhibition potential of new spiro(lactone-cyclohexanone) compounds in two different human leukemia cell lines (U937 and K562). The anti-proliferative effects of the spiro(lactone-cyclohexanone) compounds on human K562 and U937 cell lines was evaluated by trypan blue staining, as well as their involvement in NF-kB regulation were analyzed by luciferase reporter gene assay, Caspase-3/7 activities were evaluated to analyze apoptosis induction. Both spiro(coumarin-cyclohexanone) 4 and spiro(6- methyllactone-cyclohexanone) 9 down-regulated cancer cell viability and proliferation. Compound 4 inhibited TNF-α-induced NF-ĸB activation in a dose-dependent manner and induced caspase-dependent apoptosis in both leukemia cell lines. Results show that compound 4 and compound 9 have potential as anti-cancer agents. In addition, compound 4 exerted NF-kB inhibition activity in leukemia cancer cells. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  7. The DNA binding site specificity and antiproliferative property of ternary Pt(II) and Zn(II) complexes of phenanthroline and N,N'-ethylenediaminediacetic acid.

    Science.gov (United States)

    Nakamura, Yusuke; Taruno, Yoko; Sugimoto, Masashi; Kitamura, Yusuke; Seng, Hoi Ling; Kong, Siew Ming; Ng, Chew Hee; Chikira, Makoto

    2013-03-14

    The binding site specificity of the ternary complexes, [M(II)(phen)(edda)] (M(II) = Pt(2+) and Zn(2+); phen = 1,10-phenanthroline; edda = N,N'-ethylenediaminediacetic acid), for the self-complementary oligonucleotides (ODNs), ds(C(1)G(2)C(3)G(4)A(5)A(6)T(7)T(8)C(9)G(10)C(11)G(12))(2) (ODN1) and ds(C(1)G(2)C(3)G(4)T(5)A(6)T(7)A(8)C(9)G(10)C(11)G(12))(2) (ODN2), was studied by NMR measurements. The results indicated that [Pt(ii)(phen)(edda)] was partially intercalated between C(3)/G(10) and G(4)/C(9) base pairs of ODN1 and ODN2 in the major grooves, whereas [Zn(II)(phen)(edda)] was bound specifically to the TATA region of ODN2 in the minor groove and to the terminal G(2)/C(11) base pair of ODN1 in the major groove. The preference for the TATA sequence over the AATT sequence in the binding of [Zn(phen)(edda)] was attributed to the wider minor groove width of the TATA sequence. The bindings of the complexes to ct-DNA were also studied by UV, CD, and fluorescence spectroscopy. Additionally, the antiproliferative property of [Pt(II)(phen)(edda)] towards MCF7 breast cancer cells and normal MCF10-A cells was compared with that of [Zn(II)(phen)(edda)].

  8. In vivo assessment of the antiproliferative properties of interferon-alpha during immunotherapy: Ki-67 (MIB-1) in patients with metastatic renal cell carcinoma

    DEFF Research Database (Denmark)

    Donskov, F; Marcussen, N; Hokland, M

    2004-01-01

    The aim of the present study was to investigate the in vivo antiproliferative effect of interferon alpha (IFN-alpha) in patients with metastatic renal cell carcinoma (mRCC). Core needle biopsies of metastatic and/or the primary kidney cancer were obtained before interleukin-2 (IL-2)- and IFN...

  9. Structure, solution chemistry, antiproliferative actions and protein binding properties of non-conventional platinum(ii) compounds with sulfur and phosphorus donors

    NARCIS (Netherlands)

    Mügge, C.; Rothenburger, C.; Beyer, A.; Görls, H.; Gabbiani, C.; Casini, A.; Michelucci, E.; Landini, I.; Nobili, S.; Mini, E.; Messori, L.; Weigand, W.

    2011-01-01

    Twelve Pt(ii) complexes with cis-PtP2S2 pharmacophores (where P2 refers to two monodentate or one bidentate phosphane ligand and S2 is a dithiolato ligand) were prepared, characterized and evaluated as potential antiproliferative agents. The various compounds were first studied from the structural

  10. Tumorigenic and Antiproliferative Properties of the TALE-Transcription Factors MEIS2D and MEIS2A in Neuroblastoma.

    Science.gov (United States)

    Groß, Anja; Schulz, Catrine; Kolb, Jasmine; Koster, Jan; Wehner, Sibylle; Czaplinski, Sebastian; Khilan, Abdulghani; Rohrer, Hermann; Harter, Patrick N; Klingebiel, Thomas; Langer, Julian D; Geerts, Dirk; Schulte, Dorothea

    2018-04-15

    Neuroblastoma is one of only a few human cancers that can spontaneously regress even after extensive dissemination, a poorly understood phenomenon that occurs in as many as 10% of patients. In this study, we identify the TALE-homeodomain transcription factor MEIS2 as a key contributor to this phenomenon. We identified MEIS2 as a MYCN-independent factor in neuroblastoma and showed that in this setting the alternatively spliced isoforms MEIS2A and MEIS2D exert antagonistic functions. Specifically, expression of MEIS2A was low in aggressive stage 4 neuroblastoma but high in spontaneously regressing stage 4S neuroblastoma. Moderate elevation of MEIS2A expression reduced proliferation of MYCN -amplified human neuroblastoma cells, induced neuronal differentiation and impaired the ability of these cells to form tumors in mice. In contrast, MEIS2A silencing or MEIS2D upregulation enhanced the aggressiveness of the tumor phenotype. Mechanistically, MEIS2A uncoupled a negative feedback loop that restricts accumulation of cellular retinoic acid, an effective agent in neuroblastoma treatment. Overall, our results illuminate the basis for spontaneous regression in neuroblastoma and identify an MEIS2A-specific signaling network as a potential therapeutic target in this common pediatric malignancy. Significance: This study illuminates the basis for spontaneous regressions that can occur in a common pediatric tumor, with implications for the development of new treatment strategies. Cancer Res; 78(8); 1935-47. ©2018 AACR . ©2018 American Association for Cancer Research.

  11. Gold(III) complexes with 2-substituted pyridines as experimental anticancer agents: solution behavior, reactions with model proteins, antiproliferative properties.

    Science.gov (United States)

    Maiore, Laura; Cinellu, Maria Agostina; Nobili, Stefania; Landini, Ida; Mini, Enrico; Gabbiani, Chiara; Messori, Luigi

    2012-03-01

    Gold(III) compounds form a family of promising cytotoxic and potentially anticancer agents that are currently undergoing intense preclinical investigations. Four recently synthesized and characterized gold(III) derivatives of 2-substituted pyridines are evaluated here for their biological and pharmacological behavior. These include two cationic adducts with 2-pyridinyl-oxazolines, [Au(pyox(R))Cl(2)][PF(6)], [pyox(R)=(S)-4-benzyl-2-(pyridin-2-yl)-4,5-dihydrooxazole, I; (S)-4-iso-propyl-2-(pyridin-2-yl)-4,5-dihydrooxazole, II] and two neutral complexes [Au(N,N'OH)Cl(2)], III, and [Au(N,N',O)Cl], IV, containing the deprotonated ligand N-(1-hydroxy-3-iso-propyl-2-yl)pyridine-2-carboxamide, N,N'H,OH, resulting from ring opening of bound pyox(R) ligand of complex II by hydroxide ions. The solution behavior of these compounds was analyzed. These behave as classical prodrugs: activation of the metal center typically takes place through release of the labile chloride ligands while the rest of the molecule is not altered; alternatively, activation may occur through gold(III) reduction. All compounds react eagerly with the model protein cyt c leading to extensive protein metalation. ESI MS experiments revealed details of gold-cyt c interactions and allowed us to establish the nature of protein bound metal containing fragments. The different behavior displayed by I and II compared to III and IV is highlighted. Remarkable cytotoxic properties, against the reference human ovarian carcinoma cell lines A2780/S and A2780/R were disclosed for all tested compounds with IC(50) values ranging from 1.43 to 6.18 μM in the sensitive cell line and from 1.59 to 10.86 μM in the resistant one. The common ability of these compounds to overcome cisplatin resistance is highlighted. The obtained results are thoroughly discussed in the frame of current knowledge on cytotoxic gold compounds. Copyright © 2011 Elsevier Inc. All rights reserved.

  12. Backbone modified TBA analogues endowed with antiproliferative activity.

    Science.gov (United States)

    Esposito, Veronica; Russo, Annapina; Amato, Teresa; Varra, Michela; Vellecco, Valentina; Bucci, Mariarosaria; Russo, Giulia; Virgilio, Antonella; Galeone, Aldo

    2017-05-01

    The thrombin binding aptamer (TBA) is endowed with antiproliferative properties but its potential development is counteracted by the concomitant anticoagulant activity. Five oligonucleotides (ODNs) based on TBA sequence (GGTTGGTGTGGTTGG) and containing l-residues or both l-residues and inversion of polarity sites have been investigated by NMR and CD techniques for their ability to form G-quadruplex structures. Furthermore, their anticoagulant (PT assay) and antiproliferative properties (MTT assay), and their resistance in fetal bovine serum have been tested. CD and NMR data suggest that the investigated ODNs are able to form right- and left-handed G-quadruplex structures. All ODNs do not retain the anticoagulant activity characteristic of TBA but are endowed with a significant antiproliferative activity against two cancerous cell lines. Their resistance in biological environment after six days is variable, depending on the ODN. A comparison between results and literature data suggests that the antiproliferative activity of the TBA analogues investigated could depends on two factors: a) biological pathways and targets different from those already identified or proposed for other antiproliferative G-quadruplex aptamers, and b) the contribution of the guanine-based degradation products. Modified TBA analogues containing l-residues and inversion of polarity sites lose the anticoagulant activity but gain antiproliferative properties against two cancer cell lines. This article is part of a Special Issue entitled "G-quadruplex" Guest Editor: Dr. Concetta Giancola and Dr. Daniela Montesarchio. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Semisynthesis, Characterization and Evaluation of New Adenosine Derivatives as Antiproliferative Agents

    Directory of Open Access Journals (Sweden)

    Francisco Valdés Zurita

    2018-05-01

    Full Text Available We describe the semisynthesis and biological effects of adenosine derivatives, which were anticipated to function as agonists for the A3 receptor. Molecular docking was used to select candidate compounds. Fifteen nucleoside derivatives were obtained through nucleophilic substitutions of the N6-position of the nucleoside precursor 6-chloropurine riboside by amines of different origin. All compounds were purified by column chromatography and further characterized by spectroscopic and spectrometric techniques, showing moderate yield. These molecules were then evaluated for their antiproliferative activity in human gastric cancer cells expressing the A3 receptor. We found that the compounds obtained have antiproliferative activity and that new structural modifications can enhance their biological activity. The ADME (Absorption, Distribution, Metabolism and Excretion properties of the most active compounds were also evaluated theoretically.

  14. Antiproliferative Properties Against Human Breast, Cervical and Ovarian Cancer Cell Lines, and Antioxidant Capacity of Leaf Aqueous Ethanolic Extract from Cotinus coggygria Scop.

    Directory of Open Access Journals (Sweden)

    Gospodinova Z.

    2017-10-01

    Full Text Available Cotinus coggygria Scop. leaf aqueous ethanolic extract was examined for its in vitro antiproliferative and antioxidant activity. Antiproliferative effect was assessed on four human gynecological cancer cell lines: breast (MCF7, T47D, cervical (HeLa and ovarian (A2780 and compared to the cell growth inhibitory effect on non-cancerous breast epithelial cell line MCF10A using MTT cell proliferation assay. Radical scavenging assay with DPPH was applied to evaluate antioxidant potential of the extract. The obtained results showed that the herb inhibited cell growth of all of the tested cancer cell lines and the highest was the cytostatic effect on A2780 cells with a half maximal inhibitory concentration (IC50 value of 30.8 μg/ml. For the other cell lines the IC50 values were in the range of 55-122.7 μg/ml. Additionally, the extract exerted considerably weaker reduction in cell proliferation of the non-cancerous cell line MCF10A compared to cancer cells, which indicates for antiproliferative selectivity. C. coggygria extract showed high free radical scavenging activity with an IC50 value of 11.2 μg/ml. The obtained data provide evidence for pharmacological potential of the tested extract and future more detailed studies concerning the molecular mechanisms of the anticancer effect of the herb are needed.

  15. Enhancing the magnetic properties of magnetic nanoparticles

    DEFF Research Database (Denmark)

    Ahlburg, Jakob; Saura-Múzquiz, Matilde; Stingaciu, Marian

    with a similar magnetic performance. There are several different ways of enhancing magnetic properties of 3d magnetic compounds. This includes, size control, core-shell particles or mixing hard and soft magnetic materials together to achieve an exchange coupling between the compounds and enhancing the magnetic...... energy product. In order to control the particle size, a hydrothermal synthesis is preferred. This followed by reduction or the oxides into either core shell particles, or a mixture of magnetic oxides and a metallic phase....

  16. Syntehsis and antiproliferative activities of chloropyridazine derivatives retain alkylsulfonyl moiety

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chae Won; Park, Myung Sook [College of Pharmacy, Duksung Women' s University, Seoul (Korea, Republic of)

    2016-11-15

    Some chloropyridazine derivatives have shown interesting pharmacodynamics properties in terms of antioxidant and anti-human rotavirus (HRV) activities (Figure 1). To date, however, no study has evaluated the antiproliferative effects of chloropyridazines in other types of human cancer cells. In conclusion, we designed and synthesized a total of five groups of alkoxy-(or alkylthio-, alkylselenyl-, alkylsufinyl alkylsulfonyl-)chloropyridazines, and their antiproliferative activity was evaluated in the human cancer cell lines. IC{sub 50} values showed that the alkylsulfonylchloropyridazine compounds exhibited more active than the other four groups having alkoxy, alkylthio, alkylselenyl, alkylsulfinyl moieties against MCF-7 and Hep2B Cells.

  17. Syntehsis and antiproliferative activities of chloropyridazine derivatives retain alkylsulfonyl moiety

    International Nuclear Information System (INIS)

    Kim, Chae Won; Park, Myung Sook

    2016-01-01

    Some chloropyridazine derivatives have shown interesting pharmacodynamics properties in terms of antioxidant and anti-human rotavirus (HRV) activities (Figure 1). To date, however, no study has evaluated the antiproliferative effects of chloropyridazines in other types of human cancer cells. In conclusion, we designed and synthesized a total of five groups of alkoxy-(or alkylthio-, alkylselenyl-, alkylsufinyl alkylsulfonyl-)chloropyridazines, and their antiproliferative activity was evaluated in the human cancer cell lines. IC_5_0 values showed that the alkylsulfonylchloropyridazine compounds exhibited more active than the other four groups having alkoxy, alkylthio, alkylselenyl, alkylsulfinyl moieties against MCF-7 and Hep2B Cells

  18. Enhancing the magnetic properties of magnetic nanoparticles

    DEFF Research Database (Denmark)

    Ahlburg, Jakob; Saura-Múzquiz, Matilde; Stingaciu, Marian

    with a similar magnetic performance. There are several different ways of enhancing magnetic properties of 3d magnetic compounds. This includes, size control, core-shell particles or mixing hard and soft magnetic materials together to achieve an exchange coupling between the compounds and enhancing the magnetic...... energy product. In order to control the particle size, a hydrothermal synthesis is preferred. This followed by reduction or the oxides into either core shell particles, or a mixture of magnetic oxides and a metallic phase.......Strong magnets with a high energy product are vital when optimizing the efficiency in the electric industry. But since the rare earth metals, normally used for making strong permanent magnets, are both expensive and difficult to mine, a great demand has come to cheaper types of magnets...

  19. Nanocrystalline permanent magnets with enhanced properties

    International Nuclear Information System (INIS)

    Leonowicz, M.

    2002-01-01

    Parameters of permanent magnets result from the combination of intrinsic properties such as saturation magnetization, magnetic exchange, and magnetocrystalline energy, as well as microstructural parameters such as phase structure, grain size, and orientation. Reduction of grain size into nanocrystalline regime (∼ 50 nm) leads to the enhanced remanence which derives from ferromagnetic exchange coupling between highly refined grains. In this study the fundamental phenomena, quantities, and structure parameters, which define nanophase permanent magnets are presented and discussed. The theoretical considerations are confronted with experimental data for nanocrystalline Sm-Fe-N type permanent magnets. (author)

  20. Antiproliferative and apoptotic activities of extracts of Asclepias subulata.

    Science.gov (United States)

    Rascón Valenzuela, Luisa Alondra; Jiménez Estrada, Manuel; Velázquez Contreras, Carlos Arturo; Garibay Escobar, Adriana; Medina Juárez, Luis Angel; Gámez Meza, Nohemi; Robles Zepeda, Ramón Enrique

    2015-01-01

    Asclepias subulata Decne. (Apocynaceae) is a shrub used in the Mexican traditional medicine for the treatment of cancer. The objective of this study was to evaluate the antiproliferative activity of methanol extract of aerial parts of A. subulata and its fractions against different cancer cell lines. Additionally, we analyzed the mechanism of action of the active fractions. Methanol extract fractions were prepared by serial extraction with n-hexane, ethyl acetate, and ethanol. The antiproliferative activity of methanol extract and its fractions was evaluated, against several murine (M12.C3.F6, RAW 264.7, and L929) and human (HeLa, A549, PC-3, LS 180, and ARPE-19) cell lines by the MTT assay, using concentrations of 0.4-400 µg/mL for 48 h. Ethanol and residual fractions were separated using silica gel column. Apoptosis induction of cancer cells was evaluated by Annexin and JC-1 staining using flow cytometry. Methanol extract and its fractions showed antiproliferative activity against all human cancer cell lines tested. Methanol extract had the highest antiproliferative activity on A549 and HeLa cells (IC50 values < 0.4 and 8.7 µg/mL, respectively). Ethanol and residual fractions exerted significant antiproliferative effect on A549 (IC50 < 0.4 µg/mL) and PC3 cells (IC50 1.4 and 5.1 µg/mL). Apoptotic assays showed that CEF7, CEF9, CRF6, and CRF5 fractions induced mitochondrial depolarization in A549 cells, 70, 73, 77, and 80%, respectively. Those fractions triggered the apoptosis mitochondrial pathway. Our data show that A. subulata extracts have potent antiproliferative properties on human cancer cell lines. This plant should be considered an important source of potent anticancer compounds.

  1. Iron(III-salophene: an organometallic compound with selective cytotoxic and anti-proliferative properties in platinum-resistant ovarian cancer cells.

    Directory of Open Access Journals (Sweden)

    Thilo S Lange

    2008-05-01

    Full Text Available In this pioneer study to the biological activity of organometallic compound Iron(III-salophene (Fe-SP the specific effects of Fe-SP on viability, morphology, proliferation, and cell-cycle progression on platinum-resistant ovarian cancer cell lines were investigated.Fe-SP displayed selective cytotoxicity against SKOV-3 and OVCAR-3 (ovarian epithelial adenocarcinoma cell lines at concentrations between 100 nM and 1 microM, while the viability of HeLa cells (epithelial cervix adenocarcinoma or primary lung or skin fibroblasts was not affected. SKOV-3 cells in contrast to fibroblasts after treatment with Fe-SP revealed apparent hallmarks of apoptosis including densely stained nuclear granular bodies within fragmented nuclei, highly condensed chromatin and chromatin fragmentation. Fe-SP treatment led to the activation of markers of the extrinsic (Caspase-8 and intrinsic (Caspase-9 pathway of apoptosis as well as of executioner Caspase-3 while PARP-1 was deactivated. Fe-SP exerted effects as an anti-proliferative agent with an IC(50 value of 300 nM and caused delayed progression of cells through S-phase phase of the cell cycle resulting in a complete S-phase arrest. When intra-peritoneally applied to rats Fe-SP did not show any systemic toxicity at concentrations that in preliminary trials were determined to be chemotherapeutic relevant doses in a rat ovarian cancer cell model.The present report suggests that Fe-SP is a potent growth-suppressing agent in vitro for cell lines derived from ovarian cancer and a potential therapeutic drug to treat such tumors in vivo.

  2. Apoptotic and antiproliferative properties of 3β-hydroxy-Δ5-steroidal congeners from a partially purified column fraction of Dendronephthya gigantea against HL-60 and MCF-7 cancer cells.

    Science.gov (United States)

    Fernando, I P Shanura; Sanjeewa, K K Asanka; Kim, Hyun-Soo; Wang, Lei; Lee, Won Woo; Jeon, You-Jin

    2018-04-01

    Organisms belonging to the genus Dendronephthya are among a group of marine invertebrates that produce a variety of terpenoids with biofunctional properties. Many of these terpenoids have been proven effective as anticancer drugs. Here, we report the antiproliferative effect of 3β-hydroxy-Δ5-steroidal congeners against the proliferation of HL-60 human leukemia cells and MCF-7 human breast cancer cells. The sterol-rich fraction (DGEHF2-1) inhibited the growth of HL-60 and MCF-7 cells with IC 50 values of 13.59 ± 1.40 and 29.41 ± 0.87 μg ml -1 respectively. Treatment with DGEHF2-1 caused a dose-dependent increase in apoptotic body formation, DNA damage and the sub-G 1 apoptotic cell population. Moreover, DGEHF2-1 downregulated the expression of Bcl-xL while upregulating Bax, caspase-9, and PARP cleavage in both HL-60 and MCF-7 cells. The steroid fraction was found to act via the mitochondria-mediated apoptosis pathway. Identification of the sterols was performed via gas chromatography-tandem mass spectrometry analysis. Studying the mechanism of the anticancer effect caused by these sterol derivatives could lead to the identification of other natural products with anticancer properties. Copyright © 2017 John Wiley & Sons, Ltd.

  3. A comparative assessment of antiproliferative properties of resveratrol and ethanol leaf extract of Anogeissus leiocarpus (DC) Guill and Perr against HepG2 hepatocarcinoma cells.

    Science.gov (United States)

    Olugbami, Jeremiah Olorunjuwon; Damoiseaux, Robert; France, Bryan; Onibiyo, Esther Modupe; Gbadegesin, Michael Adedapo; Sharma, Shivani; Gimzewski, James Kazimierz; Odunola, Oyeronke Adunni

    2017-08-02

    concentrations (12.5-25.0 μg/mL for resveratrol and 200-800 μg/mL for A2L) which are more pronounced in A2L-treated cells. Furthermore, the antioxidant status of HepG2 cells is not perturbed by resveratrol as compared with A2L. Assessment of 24-h post-treatment mitochondrial function shows that resveratrol is not mitotoxic as compared with A2L which exhibits mitotoxicity at its highest concentration. Taken together, findings from this study showed that A2L possesses strong antiproliferative activity and its prospect in the management of hepatocellular carcinoma deserves further investigation.

  4. Antiproliferative Action of Conjugated Linoleic Acid on Human MCF-7 Breast Cancer Cells Mediated by Enhancement of Gap Junctional Intercellular Communication through Inactivation of NF-κB

    Directory of Open Access Journals (Sweden)

    Md. Abdur Rakib

    2013-01-01

    Full Text Available The major conjugated linoleic acid (CLA isomers, c9,t11-CLA and t10,c12-CLA, have anticancer effects; however, the exact mechanisms underlying these effects are unknown. Evidence suggests that reversal of reduced gap junctional intercellular communication (GJIC in cancer cells inhibits cell growth and induces cell death. Hence, we determined that CLA isomers enhance GJIC in human MCF-7 breast cancer cells and investigated the underlying molecular mechanisms. The CLA isomers significantly enhanced GJIC of MCF-7 cells at 40 μM concentration, whereas CLA inhibited cell growth and induced caspase-dependent apoptosis. CLA increased connexin43 (Cx43 expression both at the transcriptional and translational levels. CLA inhibited nuclear factor-κB (NF-κB activity and enhanced reactive oxygen species (ROS generation. No significant difference was observed in the efficacy of c9,t11-CLA and t10,c12-CLA. These results suggest that the anticancer effect of CLA is associated with upregulation of GJIC mediated by enhanced Cx43 expression through inactivation of NF-κB and generation of ROS in MCF-7 cells.

  5. [The CK2 inhibitor quninalizarin enhances the anti-proliferative effect of icotinib on EGFR-TKIs-resistant cell lines and its underlying mechanisms].

    Science.gov (United States)

    Zhou, Y; Zhang, S; Li, K; Li, Q W; Zhou, F Z; Li, Z Y; Ma, H; Dong, X R; Liu, L; Wu, G; Meng, R

    2016-02-01

    adenocarcinoma cell lines, and enhances the suppressive effect of icotinib on the proliferation of EGFR-TKIs-resistant human lung adenocarcinoma cells.

  6. Enhancement of mechanical properties of 123 superconductors

    Science.gov (United States)

    Balachandran, U.

    1995-04-25

    A composition and method are disclosed of preparing YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} superconductor. Addition of tin oxide containing compounds to YBCO superconductors results in substantial improvement of fracture toughness and other mechanical properties without affect on T{sub c}. About 5-20% additions give rise to substantially improved mechanical properties.

  7. Enhancement of mechanical properties of 123 superconductors

    Science.gov (United States)

    Balachandran, Uthamalingam

    1995-01-01

    A composition and method of preparing YBa.sub.2 Cu.sub.3 O.sub.7-x superconductor. Addition of tin oxide containing compounds to YBCO superconductors results in substantial improvement of fracture toughness and other mechanical properties without affect on T.sub.c. About 5-20% additions give rise to substantially improved mechanical properties.

  8. Enhanced thermophysical properties via PAO superstructure

    Science.gov (United States)

    Pournorouz, Zahra; Mostafavi, Amirhossein; Pinto, Aditya; Bokka, Apparao; Jeon, Junha; Shin, Donghyun

    2017-01-01

    For the last few years, molten salt nanomaterials have attracted many scientists for their enhanced specific heat by doping a minute concentration of nanoparticles (up to 1% by weight). Likewise, enhancing the specific heat of liquid media is important in many aspects of engineering such as engine oil, coolant, and lubricant. However, such enhancement in specific heat was only observed for molten salts, yet other engineering fluids such as water, ethylene glycol, and oil have shown a decrease of specific heat with doped nanoparticles. Recent studies have shown that the observed specific heat enhancement resulted from unique nanostructures that were formed by molten salt molecules when interacting with nanoparticles. Thus, such enhancement in specific heat is only possible for molten salts because other fluids may not naturally form such nanostructures. In this study, we hypothesized such nanostructures can be mimicked through in situ formation of fabricated nano-additives, which are putative nanoparticles coated with useful organic materials (e.g., polar-group-ended organic molecules) leading to superstructures, and thus can be directly used for other engineering fluids. We first applied this approach to polyalphaolefin (PAO). A differential scanning calorimeter (DSC), a rheometer, and a customized setup were employed to characterize the heat capacity, viscosity, and thermal conductivity of PAO and PAO with fabricated nano-additives. Results showed 44.5% enhanced heat capacity and 19.8 and 22.98% enhancement for thermal conductivity and viscosity, respectively, by an addition of only 2% of fabricated nanostructures in comparison with pure PAO. Moreover, a partial melting of the polar-group-ended organic molecules was observed in the first thermal cycle and the peak disappeared in the following cycles. This indicates that the in situ formation of fabricated nano-additives spontaneously occurs in the thermal cycle to form nanostructures. Figure of merit analyses have

  9. Enhanced thermophysical properties via PAO superstructure.

    Science.gov (United States)

    Pournorouz, Zahra; Mostafavi, Amirhossein; Pinto, Aditya; Bokka, Apparao; Jeon, Junha; Shin, Donghyun

    2017-12-01

    For the last few years, molten salt nanomaterials have attracted many scientists for their enhanced specific heat by doping a minute concentration of nanoparticles (up to 1% by weight). Likewise, enhancing the specific heat of liquid media is important in many aspects of engineering such as engine oil, coolant, and lubricant. However, such enhancement in specific heat was only observed for molten salts, yet other engineering fluids such as water, ethylene glycol, and oil have shown a decrease of specific heat with doped nanoparticles. Recent studies have shown that the observed specific heat enhancement resulted from unique nanostructures that were formed by molten salt molecules when interacting with nanoparticles. Thus, such enhancement in specific heat is only possible for molten salts because other fluids may not naturally form such nanostructures. In this study, we hypothesized such nanostructures can be mimicked through in situ formation of fabricated nano-additives, which are putative nanoparticles coated with useful organic materials (e.g., polar-group-ended organic molecules) leading to superstructures, and thus can be directly used for other engineering fluids. We first applied this approach to polyalphaolefin (PAO). A differential scanning calorimeter (DSC), a rheometer, and a customized setup were employed to characterize the heat capacity, viscosity, and thermal conductivity of PAO and PAO with fabricated nano-additives. Results showed 44.5% enhanced heat capacity and 19.8 and 22.98% enhancement for thermal conductivity and viscosity, respectively, by an addition of only 2% of fabricated nanostructures in comparison with pure PAO. Moreover, a partial melting of the polar-group-ended organic molecules was observed in the first thermal cycle and the peak disappeared in the following cycles. This indicates that the in situ formation of fabricated nano-additives spontaneously occurs in the thermal cycle to form nanostructures. Figure of merit analyses have

  10. Antimicrobial and antiproliferative activities of stingless bee Melipona scutellaris geopropolis

    Directory of Open Access Journals (Sweden)

    da Cunha Marcos Guilherme

    2013-01-01

    Full Text Available Abstract Background Geopropolis is a type of propolis containing resin, wax, and soil, collected by threatened stingless bee species native to tropical countries and used in folk medicine. However, studies concerning the biological activity and chemical composition of geopropolis are scarce. In this study, we evaluated the antimicrobial and antiproliferative activity of the ethanolic extract of geopropolis (EEGP collected by Melipona scutellaris and its bioactive fraction against important clinical microorganisms as well as their in vitro cytotoxicity and chemical profile. Methods The antimicrobial activity of EEGP and fractions was examined by determining their minimum inhibitory concentration (MIC and minimum bactericidal concentration (MBC against six bacteria strains as well as their ability to inhibit Streptococcus mutans biofilm adherence. Total growth inhibition (TGI was chosen to assay the antiproliferative activity of EEGP and its bioactive fraction against normal and cancer cell lines. The chemical composition of M. scutellaris geopropolis was identified by reversed-phase high-performance liquid chromatography and gas chromatography–mass spectrometry. Results EEGP significantly inhibited the growth of Staphylococcus aureus strains and S. mutans at low concentrations, and its hexane fraction (HF presented the highest antibacterial activity. Also, both EEGP and HF inhibited S. mutans biofilm adherence (p Conclusions The empirical use of this unique type of geopropolis by folk medicine practitioners was confirmed in the present study, since it showed antimicrobial and antiproliferative potential against the cancer cell lines studied. It is possible that the major compounds found in this type of geopropolis are responsible for its properties.

  11. Phytochemical screening and antiproliferative effects of methanol ...

    African Journals Online (AJOL)

    Preliminary Phytochemical screening. Thin layer chromatographic profile (TLC) of methanol crude extract and antiproliferative studies were carried out in this research. Phytochemical screening revealed the presence of carbohydrate, glycoside, anthraquinone, steroid, triterpenes, saponin, tannins, flavonoids and alkaloid.

  12. Antimutagenicity and Antiproliferative Studies of Lipidic Extracts from White Shrimp (Litopenaeus vannamei

    Directory of Open Access Journals (Sweden)

    Carolina Moreno-Félix

    2010-11-01

    Full Text Available An organic extract from fresh shrimp (Litopenaeus vannamei was studied for antimutagenic and antiproliferative properties using Salmonella typhimurium tester strains TA98 and TA100 with metabolic activation (S9 and a cancer cell line (B-cell lymphoma, respectively. Shrimp extract was sequentially fractionated by thin layer chromatography (TLC and each fraction was tested for antimutagenic and antiproliferative activities. Crude organic extracts obtained from shrimp reduced the number of revertants caused by aflatoxina B1, showing a dose-response type of relationship. Sequential TLC fractionation of the active extracts produced several antimutagenic and/or antiproliferative fractions. These results suggested that the lipid fraction of the tested species contained compounds with chemoprotective properties that reduce the mutagenicity of AFB1 and proliferation of a cancer cell line.

  13. Bioactive Lipidic Extracts from Octopus (Paraoctopus limaculatus: Antimutagenicity and Antiproliferative Studies

    Directory of Open Access Journals (Sweden)

    Carolina Moreno-Félix

    2013-01-01

    Full Text Available Fractions from an organic extract from fresh octopus (Paraoctopus limaculatus were studied for biological activities such as antimutagenic and antiproliferative properties using Salmonella tester strains TA98 and TA100 with metabolic activation (S9 and a cancer cell line (B-cell lymphoma, respectively. A chloroform extract obtained from octopus tentacles was sequentially fractionated using thin layer chromatography (TLC, and each fraction was tested for antimutagenic and antiproliferative activities. Organic extract reduced the number of revertants caused by aflatoxin B1 showing a dose-response type of relationship. Sequential TLC fractionation of the active extracts produced several antimutagenic and/or antiproliferative fractions. Based on the results obtained, the isolated fractions obtained from octopus contain compounds with chemoprotective properties that reduce the mutagenicity of AFB1 and proliferation of cancer cell lines.

  14. Composite Materials with Magnetically Aligned Carbon Nanoparticles Having Enhanced Electrical Properties and Methods of Preparation

    Science.gov (United States)

    Hong, Haiping (Inventor); Peterson, G.P. (Bud) (Inventor); Salem, David R. (Inventor)

    2016-01-01

    Magnetically aligned carbon nanoparticle composites have enhanced electrical properties. The composites comprise carbon nanoparticles, a host material, magnetically sensitive nanoparticles and a surfactant. In addition to enhanced electrical properties, the composites can have enhanced mechanical and thermal properties.

  15. Eco-friendly synthesis, in vitro anti-proliferative evaluation, and 3D-QSAR analysis of a novel series of monocationic 2-aryl/heteroaryl-substituted 6-(2-imidazolinyl)benzothiazole mesylates.

    Science.gov (United States)

    Racané, Livio; Ptiček, Lucija; Sedić, Mirela; Grbčić, Petra; Kraljević Pavelić, Sandra; Bertoša, Branimir; Sović, Irena; Karminski-Zamola, Grace

    2018-04-17

    positively correlated with anti-proliferative activity, while compound's capability to accept H-bond was identified as a negatively correlated property. Comparison of molecular properties identified for different cell lines enabled assumptions about similarity of mode of action through which anti-proliferative activities against different cell lines are accomplished. Novel compounds that are predicted to have enhanced activities in comparison with herein presented ones were designed using 3D-QSAR analysis as guideline.

  16. Enhancement of nonlinear optical properties of compounds of silica ...

    Indian Academy of Sciences (India)

    Enhancement of nonlinear optical properties of compounds of silica glass and metallic nanoparticle. A GHARAATI1,∗ and A KAMALDAR1,2. 1Department of Physics, Payame Noor University, P.O. Box 19395-3697, Tehran, Iran. 2Department of Education 1, Shiraz, Iran. ∗. Corresponding author. E-mail: agharaati@pnu.ac.

  17. A comparative study of the flow enhancing properties of bentonite ...

    African Journals Online (AJOL)

    A comparative study of granule flow enhancing property of bentonite, magnesium stearate, talc and microcrystalline cellulose (MCC) was undertaken. Bentonite was processed into fine powder. A 10 %w/w of starch granules was prepared and separated into different sizes (˂180, 180-500, 500-710 and 710-850 μm).

  18. Enhanced photocatalytic properties in well-ordered mesoporous WO3

    KAUST Repository

    Li, Li; Krissanasaeranee, Methira; Pattinson, Sebastian W.; Stefik, Morgan; Wiesner, Ulrich; Steiner, Ullrich; Eder, Dominik

    2010-01-01

    We used polyisoprene-block-ethyleneoxide copolymers as structure-directing agents to synthesise well-ordered and highly-crystalline mesoporous WO 3 architectures that possess improved photocatalytic properties due to enhanced dye-adsorption in absence of diffusion limitation. © 2010 The Royal Society of Chemistry.

  19. Enhancement of nonlinear optical properties of compounds of silica

    Indian Academy of Sciences (India)

    The aim of this paper is to introduce a method for enhancing the nonlinear optical properties in silica glass by using metallic nanoparticles. First, the T-matrix method is developed to calculate the effective dielectric constant for the compound of silica glass and metallic nanoparticles, both of which possess nonlinear dielectric ...

  20. Enhancement in magnetic properties of magnesium substituted bismuth ferrite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jianlong; Xie, Dan, E-mail: xiedan@mail.tsinghua.edu.cn, E-mail: RenTL@mail.tsinghua.edu.cn; Teng, Changjiu; Zhang, Xiaowen; Zhang, Cheng; Sun, Yilin; Ren, Tian-Ling, E-mail: xiedan@mail.tsinghua.edu.cn, E-mail: RenTL@mail.tsinghua.edu.cn [Institute of Microelectronics, Tsinghua National Laboratory for Information Science and Technology (TNList), Tsinghua University, Beijing 100084 (China); Zeng, Min; Gao, Xingsen [Institute for Advanced Materials and Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou 510006 (China); Zhao, Yonggang [Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084 (China)

    2015-06-14

    We report a potential way to effectively improve the magnetic properties of BiFeO{sub 3} (BFO) nanoparticles through Mg{sup 2+} ion substitution at the Fe-sites of BFO lattice. The high purity and structural changes induced by Mg doping are confirmed by X-ray powder diffractometer and Raman spectra. Enhanced magnetic properties are observed in Mg substituted samples, which simultaneously exhibit ferromagnetic and superparamagnetic properties at room temperature. A physical model is proposed to support the observed ferromagnetism of Mg doped samples, and the superparamagnetic properties are revealed by the temperature dependent magnetization measurements. The improved magnetic properties and soft nature obtained by Mg doping in BFO nanoparticles demonstrate the possibility of BFO nanoparticles to practical applications.

  1. Antimicrobial and antiproliferative activities of stingless bee Melipona scutellaris geopropolis.

    Science.gov (United States)

    da Cunha, Marcos Guilherme; Franchin, Marcelo; de Carvalho Galvão, Lívia Câmara; de Ruiz, Ana Lúcia Tasca Góis; de Carvalho, João Ernesto; Ikegaki, Masarahu; de Alencar, Severino Matias; Koo, Hyun; Rosalen, Pedro Luiz

    2013-01-28

    Geopropolis is a type of propolis containing resin, wax, and soil, collected by threatened stingless bee species native to tropical countries and used in folk medicine. However, studies concerning the biological activity and chemical composition of geopropolis are scarce. In this study, we evaluated the antimicrobial and antiproliferative activity of the ethanolic extract of geopropolis (EEGP) collected by Melipona scutellaris and its bioactive fraction against important clinical microorganisms as well as their in vitro cytotoxicity and chemical profile. The antimicrobial activity of EEGP and fractions was examined by determining their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against six bacteria strains as well as their ability to inhibit Streptococcus mutans biofilm adherence. Total growth inhibition (TGI) was chosen to assay the antiproliferative activity of EEGP and its bioactive fraction against normal and cancer cell lines. The chemical composition of M. scutellaris geopropolis was identified by reversed-phase high-performance liquid chromatography and gas chromatography-mass spectrometry. EEGP significantly inhibited the growth of Staphylococcus aureus strains and S. mutans at low concentrations, and its hexane fraction (HF) presented the highest antibacterial activity. Also, both EEGP and HF inhibited S. mutans biofilm adherence (p < 0.05) and showed selectivity against human cancer cell lines, although only HF demonstrated selectivity at low concentrations. The chemical analyses performed suggest the absence of flavonoids and the presence of benzophenones as geopropolis major compounds. The empirical use of this unique type of geopropolis by folk medicine practitioners was confirmed in the present study, since it showed antimicrobial and antiproliferative potential against the cancer cell lines studied. It is possible that the major compounds found in this type of geopropolis are responsible for its properties.

  2. Comparative Antioxidant, Antiproliferative and Apoptotic Effects of ...

    African Journals Online (AJOL)

    Purpose: To determine and compare the antioxidant, antiproliferative and apoptotic effects of leaf infusions of Ilex laurina ... Both plant infusions inhibited viability and cell growth of SW480 and SW620 cells. .... 100 g of dry extract, from a gallic acid calibration curve [9]. ..... antioxidant capacity and in vitro inhibition of colon.

  3. Ribonucleases, nucleases and antiangiogenins in antiproliferative activities

    Czech Academy of Sciences Publication Activity Database

    Matoušek, Josef

    2011-01-01

    Roč. 6, č. 3 (2011), s. 363-382 ISSN 1574-3624 R&D Projects: GA ČR GA521/06/1149; GA ČR GA521/09/1214 Institutional research plan: CEZ:AV0Z50450515 Keywords : Angiogenin * Anticancer * Antiproliferative Subject RIV: CE - Biochemistry Impact factor: 0.500, year: 2011

  4. Comparative Antioxidant, Antiproliferative and Apoptotic Effects of ...

    African Journals Online (AJOL)

    Purpose: To determine and compare the antioxidant, antiproliferative and apoptotic effects of leaf infusions of Ilex laurina and Ilex paraguariensis in colon cancer cells. Methods: Antioxidant activity was determined by ORAC (Oxygen Radical Absorbance Capacity) and FRAP (Ferric Reducing Antioxidant Power). Cytotoxic ...

  5. Antiproliferative activity of cardenolide glycosides from Asclepias subulata.

    Science.gov (United States)

    Rascón-Valenzuela, L; Velázquez, C; Garibay-Escobar, A; Medina-Juárez, L A; Vilegas, W; Robles-Zepeda, R E

    2015-08-02

    Asclepias subulata Decne. is a shrub occurring in Sonora-Arizona desert (Mexico-USA). The ethnic groups, Seris and Pimas, use this plant for the treatment of sore eyes, gastrointestinal disorders and cancer. To isolate the compounds responsible for antiproliferative activity of the methanol extract of A. subulata. A bioguided fractionation of methanol extract of A. subulata was performed using MTT assay to measure the antiproliferative activity of different compounds on three human cancer cell lines (A549, LS 180 and PC-3), one murine cancer cell line (RAW 264.7) and one human normal cell line (ARPE-19). The methanol extract was partitioned with hexane, ethyl acetate and ethanol. The active fractions, ethanol and residual, were fractioned by silica-column chromatography and active sub-fractions were separated using HPLC. The chemical structures of isolated compounds were elucidated with different chemical and spectroscopic methods. A new cardenolide glycoside, 12, 16-dihydroxycalotropin, and three known, calotropin, corotoxigenin 3-O-glucopyranoside and desglucouzarin, were isolated of active sub-fractions. All isolated compounds showed a strong antiproliferative activity in human cancer cells. Calotropin was the more active with IC50 values of 0.0013, 0.06 and 0.41 µM on A549, LS 180 and PC-3 cell lines, respectively; while 12, 16-dihydroxycalotropin reached values of 2.48, 5.62 and 11.70 µM, on the same cells; corotoxigenin 3-O-glucopyranoside had IC50 of 2.64, 3.15 and 6.62 µM and desglucouzarin showed values of 0.90, 6.57 and 6.62, µM. Doxorubicin, positive control, showed IC50 values of 1.78, 6.99 and 3.18 µM, respectively. The isolated compounds had a weak effect on murine cancer cells and human normal cells, exhibiting selectivity to human cancer cells. In this study, we found that 12, 16-dihydroxicalotropin, calotropin, corotoxigenin 3-O-glucopyranoside and desglucouzarin are responsible of antiproliferative properties of A. subulata, and that these

  6. Antiproliferative and Antioxidant Activities of Wild Boletales Mushrooms from France.

    Science.gov (United States)

    Morel, Sylvie; Arnould, Stéphanie; Vitou, Manon; Boudard, Frédéric; Guzman, Caroline; Poucheret, Patrick; Fons, Françoise; Rapior, Sylvie

    2018-01-01

    We selected edible and inedible mushrooms growing in the Mediterranean area of France to screen their biological activity: Caloboletus calopus, Rubroboletus lupinus, R. pulchrotinctus, R. satanas, Gyroporus castaneus, Suillus luteus, and Omphalotus olearius. Mushrooms were sequentially extracted using cyclohexane, chloroform, ethanol, and water. The antiproliferative activity against the HCT116 colon adenocarcinoma cell line and the antioxidant properties (DPPH radical scavenging assay, Folin-Ciocalteu assay, and oxygen radical absorbance capacity) of the Boletales extracts were evaluated and compared. Among the 28 mushroom extracts evaluated, 11 presented antiproliferative activity against HCT116 cells. These activities were not linked to antioxidant capacity. Among the antioxidant extracts, most were aqueous extracts in the oxygen radical absorbance capacity assay, whereas the highest values on the Folin-Ciocalteu and DPPH assays were noted for chloroform, ethanol, or aqueous extracts, depending on the mushroom species. Further studies are necessary to identify bioactive compounds and to valorize the mushrooms-for edible species, directly as health foods, or, for inedible mushrooms, as ingredients in the pharmaceutical and food industries.

  7. Synthesis, DNA Binding, and Antiproliferative Activity of Novel Acridine-Thiosemicarbazone Derivatives

    Directory of Open Access Journals (Sweden)

    Sinara Mônica Vitalino de Almeida

    2015-06-01

    Full Text Available In this work, the acridine nucleus was used as a lead-compound for structural modification by adding different substituted thiosemicarbazide moieties. Eight new (Z-2-(acridin-9-ylmethylene-N-phenylhydrazinecarbothioamide derivatives (3a–h were synthesized, their antiproliferative activities were evaluated, and DNA binding properties were performed with calf thymus DNA (ctDNA by electronic absorption and fluorescence spectroscopies. Both hyperchromic and hypochromic effects, as well as red or blue shifts were demonstrated by addition of ctDNA to the derivatives. The calculated binding constants ranged from 1.74 × 104 to 1.0 × 106 M−1 and quenching constants from −0.2 × 104 to 2.18 × 104 M−1 indicating high affinity to ctDNA base pairs. The most efficient compound in binding to ctDNA in vitro was (Z-2-(acridin-9-ylmethylene-N- (4-chlorophenyl hydrazinecarbothioamide (3f, while the most active compound in antiproliferative assay was (Z-2-(acridin-9-ylmethylene-N-phenylhydrazinecarbothioamide (3a. There was no correlation between DNA-binding and in vitro antiproliferative activity, but the results suggest that DNA binding can be involved in the biological activity mechanism. This study may guide the choice of the size and shape of the intercalating part of the ligand and the strategic selection of substituents that increase DNA-binding or antiproliferative properties.

  8. 2014 Enhanced LAW Glass Property-Composition Models, Phase 2

    Energy Technology Data Exchange (ETDEWEB)

    Muller, Isabelle [The Catholic Univ. of America, Washington, DC (United States); Pegg, Ian L. [The Catholic Univ. of America, Washington, DC (United States); Joseph, Innocent [Energy Solutions, Salt Lake City, UT (United States); Gilbo, Konstantin [The Catholic Univ. of America, Washington, DC (United States)

    2015-10-28

    This report describes the results of testing specified by the Enhanced LAW Glass Property-Composition Models, VSL-13T3050-1, Rev. 0 Test Plan. The work was performed in compliance with the quality assurance requirements specified in the Test Plan. Results required by the Test Plan are reported. The te4st results and this report have been reviewed for correctness, technical adequacy, completeness, and accuracy.

  9. Enhancement of porous silicon photoluminescence property by lithium chloride treatment

    Science.gov (United States)

    Azaiez, Khawla; Zaghouani, Rabia Benabderrahmane; Khamlich, Saleh; Meddeb, Hosny; Dimassi, Wissem

    2018-05-01

    Porous silicon (PS) decorated by several nanostructured metal elements has still aroused interests as promising composites in many industrial applications. With the focus mainly on the synthesis, the aspect of stability against optical irradiation of such materials has so far not been thoroughly addressed. This work focuses primarily on the influence of lithium chloride solution (LiCl) treatment on the physical properties of PS. Variations in the structural and optoelectronic properties of PS were observed after immersion in (LiCl), as revealed by the obtained analyses. Moreover, enhanced photoluminescence (PL) property of the PS after passivation by lithium particles was clearly shown, and their presence on the surface of the microporous silicon was confirmed by FTIR spectroscopy and atomic force microscopy. An improvement of the minority carrier lifetime was also obtained, which was attributed to the decrease of the surface recombination velocity after LiCl treatment.

  10. Ozone treatment of polysaccharides from Arthrocnemum indicum: Physico-chemical characterization and antiproliferative activity.

    Science.gov (United States)

    Mzoughi, Zeineb; Chakroun, Ibtissem; Hamida, Sarra Ben; Rihouey, Christophe; Mansour, Hedi Ben; Le Cerf, Didier; Majdoub, Hatem

    2017-12-01

    The isolation, purification and ozone depolymerization of polysaccharides from Arthrocnemum indicum as well as the evaluation of their antiproliferative capacities were investigated. The ozone treatment for various reaction times (0, 15, 30, 45 and 60min) was employed as degradation method in order to attain lower molecular weight product with stronger antiproliferative property. According to FTIR, 1 H NMR and UV-vis analysis, the main chain of ozonolytic degraded polysaccharides could be preserved. The monosaccharide composition, which was determined via GC/MS analysis, showed that extracted polysaccharides were of type of arabinan-rich pectic polysaccharides. Macromolecular characteristics as well as intrinsic viscosity of the degraded polysaccharides were performed by size exclusion chromatography before and after ozone treatment. These experiments showed that intrinsic viscosity and molecular weight (Mn and Mw) of degraded samples decreased with increase in reaction time. Furthermore, preliminary antiproliferative tests indicated that degraded polysaccharide for 1h showed even better antiproliferative capacity. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Enhanced Photovoltaic Properties of Gradient Doping Solar Cells

    International Nuclear Information System (INIS)

    Zhang Chun-Lei; Du Hui-Jing; Zhu Jian-Zhuo; Xu Tian-Fu; Fang Xiao-Yong

    2012-01-01

    An optimum design of a-Si:H(n)/a-Si:H(i)/c-Si(p) heterojunction solar cell is realized with 24.27% conversion efficiency by gradient doping of the a-Si:H(n) layer. The photovoltaic properties are simulated by the AFORSHET software. Besides the additional electric field caused by the gradient doping, the enhanced and widen spectral response also improves the solar cell performance compared with the uniform-doping mode. The simulation shows that the gradient doping is efficient to improve the photovoltaic performance of the solar cells. The study is valuable for the solar cell design with excellent performances

  12. Enhancement of mechanical properties of epoxy/graphene nanocomposite

    Science.gov (United States)

    Berhanuddin, N. I. C.; Zaman, I.; Rozlan, S. A. M.; Karim, M. A. A.; Manshoor, B.; Khalid, A.; Chan, S. W.; Meng, Q.

    2017-10-01

    Graphene is a novel class of nanofillers possessing outstanding characteristics including most compatible with most polymers, high absolute strength, high aspect ratio and cost effectiveness. In this study, graphene was used to reinforce epoxy as a matrix, to enhance its mechanical properties. Two types of epoxy composite were developed which are epoxy/graphene nanocomposite and epoxy/modified graphene nanocomposite. The fabrication of graphene was going through thermal expansion and sonication process. Chemical modification was only done for modified graphene where 4,4’-Methylene diphenyl diisocyanate (MDI) is used. The mechanical properties of both nanocomposite, such as Young’s modulus and maximum stress were investigated. Three weight percentage were used for this study which are 0.5 wt%, 1.0 wt% and 1.5 wt%. At 0.5 wt%, modified and unmodified shows the highest value compared to neat epoxy, where the value were 8 GPa, 6 GPa and 0.675 GPa, respectively. For maximum stress, neat epoxy showed the best result compared to both nanocomposite due to the changes of material properties when adding the filler into the matrix. Therefore, both nanocomposite increase the mechanical properties of the epoxy, however modification surface of graphene gives better improvement.

  13. Antiproliferative, Antimicrobial and Apoptosis Inducing Effects of Compounds Isolated from Inula viscosa

    Directory of Open Access Journals (Sweden)

    Wamidh H. Talib

    2012-03-01

    Full Text Available The antiproliferative and antimicrobial effects of thirteen compounds isolated from Inula viscosa (L. were tested in this study. The antiproliferative activity was tested against three cell lines using the MTT assay. The microdilution method was used to study the antimicrobial activity against two Gram positive bacteria, two Gram negative bacteria and one fungus. The apoptotic activity was determined using a TUNEL colorimetric assay. Scanning electron microscopy was used to study the morphological changes in treated cancer cells and bacteria. Antiproliferative activity was observed in four flavonoids (nepetin, 3,3′-di-O-methylquercetin, hispidulin, and 3-O-methylquercetin. 3,3′-di-O-Methylquercetin and 3-O-methylquercetin showed selective antiproliferative activity against MCF-7 cells, with IC50 values of 10.11 and 11.23 µg/mL, respectively. Both compounds exert their antiproliferative effect by inducing apoptosis as indicted by the presence of DNA fragmentation, nuclear condensation, and formation of apoptotic bodies in treated cancer cells. The antimicrobial effect of Inula viscosa were also noticed in 3,3′-di-O-methylquercetin and 3-O-methyquercetin that inhibited Bacillus cereus at MIC of 62.5 and 125 µg/mL, respectively. Salmonella typhimurium was inhibited by both compounds at MIC of 125 µg/mL. 3,3′-di-O-Methylquercetin induced damage in bacterial cell walls and cytoplasmic membranes. Methylated quercetins isolated from Inula viscosa have improved anticancer and antimicrobial properties compared with other flavonoids and are promising as potential anticancer and antimicrobial agents.

  14. Biocatalytically Oligomerized Epicatechin with Potent and Specific Anti-proliferative Activity for Human Breast Cancer Cells

    Directory of Open Access Journals (Sweden)

    Ramaswamy Nagarajan

    2008-11-01

    Full Text Available Catechins, naturally occurring flavonoids derived from wine and green tea, are known to exhibit multiple health benefits. Epigallocatechin gallate (EGCG is one of the most widely investigated catechins, but its efficacy in cancer therapy is still inconsistent and limited. The poor stability of EGCG has contributed to the disparity in the reported anti-cancer activity and other beneficial properties. Here we report an innovative enzymatic strategy for the oligomerization of catechins (specifically epicatechin that yields stable, water-soluble oligomerized epicatechins with enhanced and highly specific anti-proliferative activity for human breast cancer cells. This one-pot oxidative oligomerization is carried out in ambient conditions using Horseradish Peroxidase (HRP as a catalyst yielding water-soluble oligo(epicatechins. The oligomerized epicatechins obtained exhibit excellent growth inhibitory effects against human breast cancer cells with greater specificity towards growth-inhibiting cancer cells as opposed to normal cells, achieving a high therapeutic differential. Our studies indicate that water-soluble oligomeric epicatechins surpass EGCG in stability, selectivity and efficacy at lower doses.

  15. Synthesis of urease hybrid nanoflowers and their enhanced catalytic properties.

    Science.gov (United States)

    Somturk, Burcu; Yilmaz, Ismail; Altinkaynak, Cevahir; Karatepe, Aslıhan; Özdemir, Nalan; Ocsoy, Ismail

    2016-05-01

    Increasing numbers of materials have been extensively used as platforms for enzyme immobilization to enhance catalytic activity and stability. Although stability of enzyme was accomplished with immobilization approaches, activity of the most of the enzymes was declined after immobilization. Herein, we synthesize the flower shaped-hybrid nanomaterials called hybrid nanoflower (HNF) consisting of urease enzyme and copper ions (Cu(2+)) and report a mechanistic elucidation of enhancement in both activity and stability of the HNF. We demonstrated how experimental factors influence morphology of the HNF. We proved that the HNF (synthesized from 0.02mgmL(-1) urease in 10mM PBS (pH 7.4) at +4°C) exhibited the highest catalytic activity of ∼2000% and ∼4000% when stored at +4°C and RT, respectively compared to free urease. The highest stability was also achieved by this HNF by maintaining 96.3% and 90.28% of its initial activity within storage of 30 days at +4°C and RT, respectively. This dramatically enhanced activity is attributed to high surface area, nanoscale-entrapped urease and favorable urease conformation of the HNF. The exceptional catalytic activity and stability properties of HNF can be taken advantage of to use it in fields of biomedicine and chemistry. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Enhancement in thermal and mechanical properties of bricks

    Directory of Open Access Journals (Sweden)

    Shibib Khalid S.

    2013-01-01

    Full Text Available A new type of porous brick is proposed. Sawdust is initially well mixed with wet clay in order to create voids inside the brick during the firing process. The voids will enhance the total performance of the brick due to the reduction of its density and thermal conductivity and a minor reduction of its compressive stress. All these properties have been measured experimentally and good performance has been obtained. Although a minor reduction in compressive stress has been observed with increased porosity, this property has still been larger than that of the common used hollow brick. Data obtained by this work lead to a new type of effective brick having a good performance with no possibility that mortar enters inside the holes which is the case with the common used hollow bricks. The mortar has a determent effect on thermal properties of the wall since it has some higher thermal conductivity and density than that of brick which increases the wall overall density and thermal conductivity of the wall.

  17. Synthesis and antiproliferative activity of 6-phenylaminopurines.

    Science.gov (United States)

    Canela, María-Dolores; Liekens, Sandra; Camarasa, María-José; Priego, Eva María; Pérez-Pérez, María-Jesús

    2014-11-24

    A series of novel 6-phenylaminopurines have been efficiently synthesized in 3 steps exploring different groups at positions 2, 8 and 9 of the purine ring and at the exocyclic nitrogen atom at position 6. Among the newly described purines, five compounds showed antiproliferative activity with IC50 values below 10 μM, the tetrahydroquinoline derivative at position 6 of phenylaminopurine being the most active of the series in the six cell lines tested. Moreover, the compounds induced G2/M phase arrest in human cervical carcinoma HeLa cells as reported for tubulin depolymerizing agents. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  18. Antiproliferative activity of recombinant human interferon-λ2 ...

    African Journals Online (AJOL)

    Antiproliferative activity of recombinant human interferon-λ2 expressed in stably ... The representing 26 kDa protein band of IFN-λ2 was detected by SDS-PAGE and ... The antiproliferative activity of hIFN-λ2 was determined by MTT assay.

  19. Antiproliferative effect of alcoholic extracts of some Gabonese ...

    African Journals Online (AJOL)

    Extracts from Piptadeniastrum africanum Brenan (Mimosaceae), Petersianthus macrocarpus (Breauv) L. (Lecydaceae), Cissus debilis Planch (Vitaceae) and Dieffenbachia seguine Jacq. (Araceae) were tested in vitro for their antiproliferative activity on human colon cancer cell line (CaCo-2). The highest antiproliferative ...

  20. Magnetic nanofluid properties as the heat transfer enhancement agent

    Directory of Open Access Journals (Sweden)

    Roszko Aleksandra

    2016-01-01

    Full Text Available The main purpose of this paper was to investigate an influence of various parameters on the heat transfer processes with strong magnetic field utilization. Two positions of experimental enclosure in magnetic environment, two methods of preparation and three different concentrations of nanoparticles (0.0112, 0.056 and 0.112 vol.% were taken into account together with the magnetic field strength. Analysed nanofluids consisted of distilled water (diamagnetic and Cu/CuO particles (paramagnetic of 40–60 nm size. The nanofluids components had different magnetic properties what caused complex interaction of forces’ system. The heat transfer data and fluid flow structure demonstrated the influence of magnetic field on the convective phenomena. The most visible consequence of magnetic field application was the heat transfer enhancement and flow reorganization under applied conditions.

  1. Enhancing the engineering properties of expansive soil using bagasse ash

    Science.gov (United States)

    Silmi Surjandari, Niken; Djarwanti, Noegroho; Umri Ukoi, Nafisah

    2017-11-01

    This paper deals with stabilization of expansive soil on a laboratory experimental basis. The aim of the research was to evaluate the enhancement of the engineering properties of expansive soil using bagasse ash. The soil is treated with bagasse ash by weight (0, 5, 10, 15, and 20%) based on dry mass. The performance of bagasse ash stabilized soil was evaluated using physical and strength performance tests, namely the plasticity index, standard Proctor compaction, and percentage swelling. An X-ray diffraction (XRD) test was conducted to evaluate the clay mineral, whereas an X-ray fluorescence (XRF) was to the chemical composition of bagasse ash. From the results, it was observed that the basic tests carried out proved some soil properties after the addition of bagasse ash. Furthermore, the plasticity index decreased from 53.18 to 47.70%. The maximum dry density of the specimen increased from 1.13 to 1.24 gr/cm3. The percentage swelling decreased from 5.48 to 3.29%. The outcomes of these tests demonstrate that stabilization of expansive soils using bagasse ash can improve the strength.

  2. Chromium carbide-CNT nanocomposites with enhanced mechanical properties

    International Nuclear Information System (INIS)

    Singh, Virendra; Diaz, Rene; Balani, Kantesh; Agarwal, Arvind; Seal, Sudipta

    2009-01-01

    Chromium carbide is widely used as a tribological coating material in high-temperature applications requiring high wear resistance and hardness. Herein, an attempt has been made to further enhance the mechanical and wear properties of chromium carbide coatings by reinforcing carbon nanotubes (CNTs) as a potential replacement of soft binder matrix using plasma spraying. The microstructures of the sprayed CNT-reinforced Cr 3 C 2 coatings were characterized using transmission electron microscopy and scanning electron microscopy. The mechanical properties were assessed using micro-Vickers hardness, nanoindentation and wear measurements. CNT reinforcement improved the hardness of the coating by 40% and decreased the wear rate of the coating by almost 45-50%. Cr 3 C 2 reinforced with 2 wt.% CNT had an elastic modulus 304.5 ± 29.2 GPa, hardness of 1175 ± 60 VH 0.300 and a coefficient of friction of 0.654. It was concluded that the CNT reinforcement increased the wear resistance by forming intersplat bridges while the improvement in the hardness was attributed to the deformation resistance of CNTs under indentation

  3. Enhanced tensile properties of magnesium composites reinforced with graphene nanoplatelets

    International Nuclear Information System (INIS)

    Rashad, Muhammad; Pan, Fusheng; Hu, Huanhuan; Asif, Muhammad; Hussain, Shahid; She, Jia

    2015-01-01

    The aim of this study is to fabricate magnesium reinforced metal matrix composites using graphene nanoplatelets (GNPs) via powder metallurgy processing in order to enhance room temperature mechanical properties. The microstructural evaluation and mechanical behaviors of composite powders and extruded bulk materials were examined by X-ray diffraction (XRD), differential scanning calorimetry (DSC), Raman spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) equipped with energy-dispersive spectrometer and mechanical tests. The uniform dispersion and large specific surface area per volume of GNPs embedded in magnesium matrix led to increament in microhardness, tensile strength and fracture strains of the composites. For example, when employing the pure magnesium reinforced with 0.30 wt% GNPs, the increase of Young's modulus, yield strength, and failure strain of extruded nanocomposite was +131%, +49.5% and +74.2% respectively, compared to those of extruded materials with no GNPs additive. Additionally, mechanical properties of synthesized composites were compared with previously reported Mg–CNTs composites. It was found that GNPs outperform CNTs due their high specific surface area

  4. Enhanced tensile properties of magnesium composites reinforced with graphene nanoplatelets

    Energy Technology Data Exchange (ETDEWEB)

    Rashad, Muhammad, E-mail: rashadphy87@gmail.com [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 (China); National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044 (China); Pan, Fusheng, E-mail: fspan@cqu.edu.cn [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 (China); National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044 (China); Chongqing Academy of Science and Technology, Chongqing 401123 (China); Hu, Huanhuan [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 (China); National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044 (China); Asif, Muhammad [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Hussain, Shahid [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 (China); She, Jia [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 (China); National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044 (China)

    2015-04-10

    The aim of this study is to fabricate magnesium reinforced metal matrix composites using graphene nanoplatelets (GNPs) via powder metallurgy processing in order to enhance room temperature mechanical properties. The microstructural evaluation and mechanical behaviors of composite powders and extruded bulk materials were examined by X-ray diffraction (XRD), differential scanning calorimetry (DSC), Raman spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) equipped with energy-dispersive spectrometer and mechanical tests. The uniform dispersion and large specific surface area per volume of GNPs embedded in magnesium matrix led to increament in microhardness, tensile strength and fracture strains of the composites. For example, when employing the pure magnesium reinforced with 0.30 wt% GNPs, the increase of Young's modulus, yield strength, and failure strain of extruded nanocomposite was +131%, +49.5% and +74.2% respectively, compared to those of extruded materials with no GNPs additive. Additionally, mechanical properties of synthesized composites were compared with previously reported Mg–CNTs composites. It was found that GNPs outperform CNTs due their high specific surface area.

  5. Synthesis of isocryptolepine analogues and their structure-activity relationship studies as antiplasmodial and antiproliferative agents.

    Science.gov (United States)

    Aroonkit, Pasuk; Thongsornkleeb, Charnsak; Tummatorn, Jumreang; Krajangsri, Suppachai; Mungthin, Mathirut; Ruchirawat, Somsak

    2015-04-13

    Novel isocryptolepine analogues have been conveniently synthesized and evaluated for antimalarial and antiproliferative activities. We have found 3-fluoro-8-bromo-isocryptolepine (1n) to have the highest activities against chloroquine-resistant K1, chloroquine-sensitive 3D7, and chloroquine- and mefloquine-resistant SKF58 and SRIV35 strains. Several fluorine-substituted analogues (1b, 1n, and 1q) also showed excellent selectivities while maintaining good to excellent activities against all four Plasmodium falciparum strains. Additionally, antiproliferative properties of isocryptolepine derivatives against HepG2, HuCCA-1, MOLT-3 and A549 cancer cell lines are reported for the first time in this study. 2-Chloroisocryptolepine (1c) and benzo-fused-2-chloroisocryptolepine (1i) showed significant bioactivities whereas several novel fluorinated compounds and 2-chloro-8-bromoisocryptolepine (1f) displayed excellent selectivities. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  6. Melipona mondury produces a geopropolis with antioxidant, antibacterial and antiproliferative activities

    Directory of Open Access Journals (Sweden)

    TÁSSIA L.A. DOS SANTOS

    Full Text Available ABSTRACT Geopropolis is a special type of propolis produced by stingless bees. Several pharmacological properties have been described for different types of geopropolis, but there have been no previous studies of the geopropolis from Melipona mondury. In this study, we investigated the antioxidant, antibacterial, and antiproliferative activities of M. mondury geopropolis, and determined its chemical profile. The antioxidant activity was determined using in vitro ABTS·+, ·DPPH, and β-carotene/linoleic acid co-oxidation methods. The antibacterial activity was determined using a microdilution method with Pseudomonas aeruginosa, Staphylococcus aureus, and methicillin-resistant S. aureus. The antiproliferative effect was determined in tumor cell lines using the Alamar Blue assay. The chemical profile was obtained using UHPLC-MS and UHPLC-MS/MS. The butanolic fraction had the highest concentration of phenolic compounds and more potent antioxidant properties in all assays. This fraction also had bacteriostatic and bactericidal effects against all bacterial strains at low concentrations, especially S. aureus. The hexane fraction had the highest antiproliferative potential, with IC50 values ranging from 24.2 to 46.6 µg/mL in HL-60 (human promyelocytic leukemia cell and K562 (human chronic myelocytic leukemia cell, respectively. Preliminary chemical analysis indicates the presence of terpenes and gallic acid in the geopropolis. Our results indicate the therapeutic potential of geopropolis from M. mondury against inflammatory, oxidative, infectious, and neoplastic diseases.

  7. Melipona mondury produces a geopropolis with antioxidant, antibacterial and antiproliferative activities.

    Science.gov (United States)

    Santos, Tássia L A Dos; Queiroz, Raphael F; Sawaya, Alexandra C H F; Lopez, Begoña Gimenez-Cassina; Soares, Milena B P; Bezerra, Daniel P; Rodrigues, Ana Carolina B C; Paula, Vanderlúcia F DE; Waldschmidt, Ana Maria

    2017-01-01

    Geopropolis is a special type of propolis produced by stingless bees. Several pharmacological properties have been described for different types of geopropolis, but there have been no previous studies of the geopropolis from Melipona mondury. In this study, we investigated the antioxidant, antibacterial, and antiproliferative activities of M. mondury geopropolis, and determined its chemical profile. The antioxidant activity was determined using in vitro ABTS·+, ·DPPH, and β-carotene/linoleic acid co-oxidation methods. The antibacterial activity was determined using a microdilution method with Pseudomonas aeruginosa, Staphylococcus aureus, and methicillin-resistant S. aureus. The antiproliferative effect was determined in tumor cell lines using the Alamar Blue assay. The chemical profile was obtained using UHPLC-MS and UHPLC-MS/MS. The butanolic fraction had the highest concentration of phenolic compounds and more potent antioxidant properties in all assays. This fraction also had bacteriostatic and bactericidal effects against all bacterial strains at low concentrations, especially S. aureus. The hexane fraction had the highest antiproliferative potential, with IC50 values ranging from 24.2 to 46.6 µg/mL in HL-60 (human promyelocytic leukemia cell) and K562 (human chronic myelocytic leukemia cell), respectively. Preliminary chemical analysis indicates the presence of terpenes and gallic acid in the geopropolis. Our results indicate the therapeutic potential of geopropolis from M. mondury against inflammatory, oxidative, infectious, and neoplastic diseases.

  8. Design of materials configurations for enhanced phononic and electronic properties

    Science.gov (United States)

    Daraio, Chiara

    The discovery of novel nonlinear dynamic and electronic phenomena is presented for the specific cases of granular materials and carbon nanotubes. This research was conducted for designing and constructing optimized macro-, micro- and nano-scale structural configurations of materials, and for studying their phononic and electronic behavior. Variation of composite arrangements of granular elements with different elastic properties in a linear chain-of-sphere, Y-junction or 3-D configurations led to a variety of novel phononic phenomena and interesting physical properties, which can be potentially useful for security, communications, mechanical and biomedical engineering applications. Mechanical and electronic properties of carbon nanotubes with different atomic arrangements and microstructures were also investigated. Electronic properties of Y-junction configured carbon nanotubes exhibit an exciting transistor switch behavior which is not seen in linear configuration nanotubes. Strongly nonlinear materials were designed and fabricated using novel and innovative concepts. Due to their unique strongly nonlinear and anisotropic nature, novel wave phenomena have been discovered. Specifically, violations of Snell's law were detected and a new mechanism of wave interaction with interfaces between NTPCs (Nonlinear Tunable Phononic Crystals) was established. Polymer-based systems were tested for the first time, and the tunability of the solitary waves speed was demonstrated. New materials with transformed signal propagation speed in the manageable range of 10-100 m/s and signal amplitude typical for audible speech have been developed. The enhancing of the mitigation of solitary and shock waves in 1-D chains were demonstrated and a new protective medium was designed for practical applications. 1-D, 2-D and 3-D strongly nonlinear system have been investigated providing a broad impact on the whole area of strongly nonlinear wave dynamics and creating experimental basis for new

  9. Evaluation of antiproliferative activity of pyrazolothiazolopyrimidine derivatives

    Directory of Open Access Journals (Sweden)

    N. S. Finiuk

    2018-04-01

    Full Text Available The research aim was to test cytotoxic effects in vitro of seven novel pyrazolothiazolopyrimidine derivatives in targeting several lines of tumor and pseudo-normal mammalian cells. We demonstrated that cytotoxic effects of these derivatives depended on the tissue origin of targeted cells. Leukemia cells were found to be the most sensitive to the action of compounds 2 and 7. Compound 2 demonstrated approximately two times higher toxicity towards the multidrug-resistant sub-line of HL-60/ADR cells compared to the Doxorubicin effect. Antiproliferative action of compounds 2 and 7 dropped in the order: leukemia > melanoma > hepatocarcinoma > glioblastoma > colon carcinoma > breast and ovarian carcinoma cells. These compounds were less toxic than Doxorubicin towards the non-tumor cells. The novel pyrazolothiazolopyrimidine, compound 2, demonstrated high toxicity towards human leukemia and, of special importance, towards multidrug-resistant leukemia cells, and low toxicity towards pseudo-normal cells.

  10. Antiproliferative effect of isopentenylated coumarins on several cancer cell lines.

    Science.gov (United States)

    Kawaii, S; Tomono, Y; Ogawa, K; Sugiura, M; Yano, M; Yoshizawa, Y; Ito, C; Furukawa, H

    2001-01-01

    33 coumarins, mainly the simple isopentenylated coumarins and derived pyrano- and furanocoumarins, were examined for their antiproliferative activity towards several cancer and normal human cell lines. The pyrano- and furanocoumarins showed strong activity against the cancer cell lines, whereas they had weak antiproliferative activity against the normal human cell lines. The decreasing rank order of potency was osthenone (10), clausarin (25), clausenidin (26), dentatin (24), nordentatin (23), imperatorin (29), seselin (27), xanthyletin (21), suberosin (17), phebalosin (8) and osthol (12). The structure-activity relationship established from the results revealed that the 1,1-dimethylallyl and isopentenyl groups have an important role for antiproliferative activity.

  11. Dielectric Property Enhancement in Polymer Composites with Engineered Interfaces

    Science.gov (United States)

    Krentz, Timothy Michael

    This thesis reports studies into the dielectric behavior of polymer composites filled with silica nanoparticles. The permittivity and dielectric breakdown strength (DBS) of these materials are critical to their performance in insulating applications such as high voltage power transmission. Until now, the mechanisms which lead to improvements in DBS in these systems have been poorly understood, in part because the effects of dispersion of the filler and the filler's surface electronic characteristics have been confused. The new surface modifications created in this thesis permit these two parameters to be addressed independently, leading to the hypothesis that nanocomposite dielectric materials exhibit DBS enhancement when electron avalanches are prevented from proceeding to reach a critical size capable of causing failure. The same control of dispersion and surface properties also lead to changes in the permittivity of the composite based upon the polarizability and trapping behavior of the filler. In this work, the dispersion and surface states of silica nanoparticles were independently controlled with two separate populations of surface molecules. Two matrix materials were studied, and in each system, a different, matrix-compatible long chain polymer is required to control dispersion. Conversely, a second population of short molecules is shown to be capable of creating electronic traps associated with the silica nanoparticle surface which lead to DBS enhancements largely independent of the matrix, indicating that the same failure mechanism is operating in both epoxy and polypropylene. Progressive variation in dispersion quality is attained with this surface modification scheme. This creates progressively smaller volumes of matrix polymer unaffected by the filler. This work shows that when these volumes approach and become smaller than the same scale as predicted for electron avalanches, the greatest changes in DBS are seen. Likewise, the plateau behavior of this

  12. Elastic Properties and Enhanced Piezoelectric Response at Morphotropic Phase Boundaries

    Directory of Open Access Journals (Sweden)

    Francesco Cordero

    2015-12-01

    Full Text Available The search for improved piezoelectric materials is based on the morphotropic phase boundaries (MPB between ferroelectric phases with different crystal symmetry and available directions for the spontaneous polarization. Such regions of the composition x − T phase diagrams provide the conditions for minimal anisotropy with respect to the direction of the polarization, so that the polarization can easily rotate maintaining a substantial magnitude, while the near verticality of the TMPB(x boundary extends the temperature range of the resulting enhanced piezoelectricity. Another consequence of the quasi-isotropy of the free energy is a reduction of the domain walls energies, with consequent formation of domain structures down to nanoscale. Disentangling the extrinsic and intrinsic contributions to the piezoelectricity in such conditions requires a high level of sophistication from the techniques and analyses for studying the structural, ferroelectric and dielectric properties. The elastic characterization is extremely useful in clarifying the phenomenology and mechanisms related to ferroelectric MPBs. The relationship between dielectric, elastic and piezoelectric responses is introduced in terms of relaxation of defects with electric dipole and elastic quadrupole, and extended to the response near phase transitions in the framework of the Landau theory. An account is provided of the anelastic experiments, from torsional pendulum to Brillouin scattering, that provided new important information on ferroelectric MPBs, including PZT, PMN-PT, NBT-BT, BCTZ, and KNN-based systems.

  13. Elastic Properties and Enhanced Piezoelectric Response at Morphotropic Phase Boundaries

    Science.gov (United States)

    Cordero, Francesco

    2015-01-01

    The search for improved piezoelectric materials is based on the morphotropic phase boundaries (MPB) between ferroelectric phases with different crystal symmetry and available directions for the spontaneous polarization. Such regions of the composition x−T phase diagrams provide the conditions for minimal anisotropy with respect to the direction of the polarization, so that the polarization can easily rotate maintaining a substantial magnitude, while the near verticality of the TMPBx boundary extends the temperature range of the resulting enhanced piezoelectricity. Another consequence of the quasi-isotropy of the free energy is a reduction of the domain walls energies, with consequent formation of domain structures down to nanoscale. Disentangling the extrinsic and intrinsic contributions to the piezoelectricity in such conditions requires a high level of sophistication from the techniques and analyses for studying the structural, ferroelectric and dielectric properties. The elastic characterization is extremely useful in clarifying the phenomenology and mechanisms related to ferroelectric MPBs. The relationship between dielectric, elastic and piezoelectric responses is introduced in terms of relaxation of defects with electric dipole and elastic quadrupole, and extended to the response near phase transitions in the framework of the Landau theory. An account is provided of the anelastic experiments, from torsional pendulum to Brillouin scattering, that provided new important information on ferroelectric MPBs, including PZT, PMN-PT, NBT-BT, BCTZ, and KNN-based systems. PMID:28793707

  14. Enhanced dielectric and electrical properties of annealed PVDF thin film

    Science.gov (United States)

    Arshad, A. N.; Rozana, M. D.; Wahid, M. H. M.; Mahmood, M. K. A.; Sarip, M. N.; Habibah, Z.; Rusop, M.

    2018-05-01

    Poly (vinylideneflouride) (PVDF) thin films were annealed at various annealing temperatures ranging from 70°C to 170°C. This study demonstrates that PVDF thin films annealed at temperature of 70°C (AN70) showed significant enhancement in their dielectric constant (14) at frequency of 1 kHz in comparison to un-annealed PVDF (UN-PVDF), dielectric constant (10) at the same measured frequency. As the annealing temperature was increased from 90°C (AN90) to 150°C (AN150), the dielectric constant value of PVDF thin films was observed to decrease gradually to 11. AN70 also revealed low tangent loss (tan δ) value at similar frequency. With respect to its resistivity properties, the values were found to increase from 1.98×104 Ω.cm to 3.24×104 Ω.cm for AN70 and UN-PVDF films respectively. The improved in dielectric constant, with low tangent loss and high resistivity value suggests that 70°C is the favorable annealing temperature for PVDF thin films. Hence, AN70 is a promising film to be utilized for application in electronic devices such as low frequency capacitor.

  15. CYP1-mediated antiproliferative activity of dietary flavonoids in MDA-MB-468 breast cancer cells

    International Nuclear Information System (INIS)

    Androutsopoulos, Vasilis P.; Ruparelia, Ketan; Arroo, Randolph R.J.; Tsatsakis, Aristidis M.; Spandidos, Demetrios A.

    2009-01-01

    Among the different mechanisms proposed to explain the cancer-protecting effect of dietary flavonoids, substrate-like interactions with cytochrome P450 CYP1 enzymes have recently been explored. In the present study, the metabolism of the flavonoids chrysin, baicalein, scutellarein, sinensetin and genkwanin by recombinant CYP1A1, CYP1B1 and CYP1A2 enzymes, as well as their antiproliferative activity in MDA-MB-468 human breast adenocarcinoma and MCF-10A normal breast cell lines, were investigated. Baicalein and 6-hydroxyluteolin were the only conversion products of chrysin and scutellarein metabolism by CYP1 family enzymes, respectively, while baicalein itself was not metabolized further. Sinensetin and genkwanin produced a greater number of metabolites and were shown to inhibit strongly in vitro proliferation of MDA-MB-468 cells at submicromolar and micromolar concentrations, respectively, without essentially affecting the viability of MCF-10A cells. Cotreatment of the CYP1 family inhibitor acacetin reversed the antiproliferative activity noticed for the two flavones in MDA-MB-468 cells to 13 and 14 μM respectively. In contrast chrysin, baicalein and scutellarein inhibited proliferation of MDA-MB-468 cells to a lesser extent than sinensetin and genkwanin. The metabolism of genkwanin to apigenin and of chrysin to baicalein was favored by CYP1B1 and CYP1A1, respectively. Taken together the data suggests that CYP1 family enzymes enhance the antiproliferative activity of dietary flavonoids in breast cancer cells, through bioconversion to more active products.

  16. Nanostructured interfaces for enhancing mechanical properties of composites: Computational micromechanical studies

    DEFF Research Database (Denmark)

    Mishnaevsky, Leon

    2015-01-01

    Computational micromechanical studies of the effect of nanostructuring and nanoengineering of interfaces, phase and grain boundaries of materials on the mechanical properties and strength of materials and the potential of interface nanostructuring to enhance the materials properties are reviewed....

  17. Antioxidant, Cytotoxic, and Antiproliferative Activities and Total Polyphenol Contents of the Extracts of Geissospermum reticulatum Bark

    Directory of Open Access Journals (Sweden)

    Joanna J. Sajkowska-Kozielewicz

    2016-01-01

    Full Text Available Geissospermum species are medically important plants due to their health-promoting effects. The objective of this study was to determine the antioxidant ability and antiproliferative and cytotoxic effects of infusions, tinctures, and ethanolic extracts of Geissospermum reticulatum barks in relation to the contents of total phenolics and flavonoids. Seven samples of barks were collected in various regions of Peruvian Amazonia. We found that the amount of total phenolics in the studied products varied from 212.40 ± 0.69 to 1253.92 ± 11.20 mg GAE/kg. In our study there is a correlation (R2=0.7947 between the results of antioxidants assays: FRAP and ORAC for tinctures, infusions, and ethanolic extracts of G. reticulatum barks. We have also observed antiproliferative activities of the ethanolic extracts on normal T-cells. These extracts have caused death on malignant cell lines (THP-1 and HL-60 and this data correlates well with their antioxidant capacity measured by ORAC method. Interestingly, the highest concentration of the ethanolic extract was not toxic in the zebrafish embryo developmental assay. Our results indicate that G. reticulatum is rich in antioxidants and have cytotoxic and antiproliferative properties. The data suggests potential immunosuppressive role of the extracts. This is the first study presenting the results of chemical and biological analysis of multiple preparations from G. reticulatum.

  18. faloabi@uniben.edu Antiproliferative and Pro-apoptotic activities

    African Journals Online (AJOL)

    MICHAEL HORSFALL

    Keyword: Persea americana, antiproliferative activity, apoptotic effect, flow ... of the stem bark of Persea americana in MCF-7 cell line by flow cytometer. .... of an electric milling machine. ... Flow Cytometric Measurement Of Cell Proliferation:.

  19. In vitro Evaluation of Antimitotic, Antiproliferative, DNA fragmentation and Anticancer activity of Chloroform and Ethanol extracts of Revia hypocrateriformis

    Directory of Open Access Journals (Sweden)

    Saboo Shweta S

    2012-05-01

    Full Text Available Objective: The plant Rivea hypocrateriformis (RH has numerous therapeutic utility in folk medicine having antidiabetic, antidepressant, analgesic as well as pregnancy irruption and anticancer properties. This led us to carry out the evaluation of plant for antimitotic, antiproliferative and cytotoxicity studies. Materials and Method: The dried aerial parts of RH were successively extracted with petroleum ether, chloroform, ethanol and water. All extracts are subjected to in vitro Antimitotic and Antiproliferative assay by Allium cepa root inhibition and yeast model. The successive chloroform, SCH and ethanol extract, SEE was subjected to in vitro anticancer activity by SRB assay MCF-7, HOP-62, MOLT-4, HCT-15 and PRO cell lines. Results: The SCH and SEE shows significant antimitotic and antiproliferative activity. The mitotic index was found to be 12.14 and 14.24 mg/mL respectively, which was near to standard, Methothrexate 11.39. The IC50 value of antiproliferative assay was found to be 47.88 to 27.12 mg/mL for SCH and SEE respectively. Conclusions: Based on these results, it is concluded that RH may be the good candidate for the treatment of cancer as SCH and SEE are cytotoxic against various cell line in SRB assay.

  20. The antiproliferative aspects of mortalin (review).

    Science.gov (United States)

    Wadhwa, R; Mitsui, Y; Ide, T; Kaul, S

    1995-07-01

    Cellular mortal and immortal phenotypes as defined by the limited and the infinite capacity of cells to divide are the characteristics of normal and cancerous cells in culture. Numerous strategies that have been employed to understand the mechanism(s) of normal as well as tumor cell growth have revealed that these are genetically controlled, however, the genes and the synchronized regulations remain largely undefined so far. The present report reviews the identification of mortalin, a novel member of murine hsp70 family of proteins, as a gene involved in pathways that determine divisional phenotype of cells in vitro. In the present study, the anti-proliferative activity of mortalin is demonstrated also in human skin fibroblasts (TIG-73PD) by microinjection of anti-mortalin antibody. Furthermore, studies on the mortalin immunofluorescence patterns in SV40-immortalized pre-crisis and post-crisis human cells have revealed that the change in the intracellular distribution of mortalin is linked to the change in the divisional phenotype of cells. Thus, the studies to resolve the molecular basis of association of the cytosolically distributed form of mortalin with cellular mortal phenotype would be important in understanding of the mechanism(s) that determine replicative potential of cells in culture.

  1. Synthesis and structure-activity relationship studies of furan-ring fused chalcones as antiproliferative agents.

    Science.gov (United States)

    Saito, Yusuke; Kishimoto, Maho; Yoshizawa, Yuko; Kawaii, Satoru

    2015-02-01

    As part of our continuing investigation of flavonoid derivatives as potential anticancer substances, the synthesis of 25 cinnamoyl derivatives of benzofuran as furan-fused chalcones was carried-out and these compounds were further evaluated for their antiproliferative activity towards HL60 promyelocytic leukemia cells. In comparison with 2',4'-dihydroxychalcone, attachment of a furan moiety on the A-ring enhanced activity by more than twofold. Benzofurans may be useful in the design of biologically active flavonoids. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  2. Antiproliferative and antimicrobial efficacy of the compounds isolated from the roots of Oenothera biennis L.

    Science.gov (United States)

    Singh, Shilpi; Dubey, Vijaya; Singh, Dhananjay Kumar; Fatima, Kaneez; Ahmad, Ateeque; Luqman, Suaib

    2017-09-01

    strong interaction with ODC (BE -4.17 to -4.46 kcal/mol). Oenotheralanosterol A (1), cetoleilyl diglucoside (2), oenotheralanosterol B (3), dihydroxyprenylxanthone acetylated (6) and dihydroxyprenylxanthone (7) inhibited CATD activity (IC 50 3.95 ± 0.49 to 24.35 ± 2.89 μg/ml). The in-silico molecular interaction analysis of compounds with CATD revealed the non-specific interaction. A moderate antimicrobial activity was observed against selected microbes with a growth inhibition ranging from 6 to 14 mm and minimum inhibitory concentration between 125 and 500 μg/ml. Oenotheralanosterol B (3) and dihydroxyprenylxanthone acetylated (6) exhibited better antimicrobial activity with an MIC range from 62.50 to 500 μg/ml. Oenotheralanosterol B (3) exhibited stronger antiproliferative and antimicrobial potential with respect to the other compounds tested, whereas oenotheralanosterol A (1) was a potent inhibitor of ODC and CATD. Hence, it is suggested that these in-vitro findings could be studied further in vivo for biological activity, safety evaluation and derivatization to enhance potency and efficacy. © 2017 Royal Pharmaceutical Society.

  3. Designing of Bulk Nano-Structures with Enhanced Thermoelectric Properties

    National Research Council Canada - National Science Library

    Kanatzidis, Mercouri; Hogan, Timothy; Murray, Chris

    2007-01-01

    .... K2Bi8Se13 is a member of this series and was found to be a promising thermoelectric. The charge transport properties were studied under pressure, where a significant increase in the power factor was observed...

  4. Designing of Bulk Nano-Structures With Enhanced Thermoelectric Properties

    National Research Council Canada - National Science Library

    Kanatzidis, Mercouri G

    2007-01-01

    .... K2Bi8Se13 is a member of this series and was found to be a promising thermoelectric. The charge transport properties were studied under pressure, where a significant increase in the power factor was observed...

  5. Verapamil stereoisomers induce antiproliferative effects in vascular smooth muscle cells via autophagy

    Energy Technology Data Exchange (ETDEWEB)

    Salabei, Joshua K. [Diabetes and Obesity Center, University of Louisville, Louisville, KY 40202 (United States); Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, KY 40202 (United States); Balakumaran, Arun [Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555‐0438 (United States); Frey, Justin C. [Department of Biology, University of Wisconsin-Eau Claire, Eau Claire, WI 54702 (United States); Boor, Paul J. [Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555‐0438 (United States); Treinen-Moslen, Mary [Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555‐0609 (United States); Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555‐0438 (United States); Conklin, Daniel J., E-mail: dj.conklin@louisville.edu [Diabetes and Obesity Center, University of Louisville, Louisville, KY 40202 (United States); Division of Cardiovascular Medicine, University of Louisville, Louisville, KY 40202 (United States); Department of Biology, University of Wisconsin-Eau Claire, Eau Claire, WI 54702 (United States); Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555‐0438 (United States)

    2012-08-01

    Calcium channel blockers (CCBs) are important in the management of hypertension and limit restenosis. Although CCB efficacy could derive from decreased blood pressure, other mechanisms independent of CCB activity also can contribute to antiproliferative action. To understand mechanisms of CCB-mediated antiproliferation, we studied two structurally dissimilar CCBs, diltiazem and verapamil, in cultured rat vascular smooth muscle cells (VSMC). To elucidate CCB-independent effects, pure stereoisomers of verapamil (R-verapamil, inactive VR; S-verapamil, active, VS) were used. The effects of CCB exposure on cell viability (MTT reduction), cell proliferation ({sup 3}H-thymidine incorporation), VSMC morphology by light and transmission electron microscopy (TEM) and autophagy (LC3I/II, ATG5) were measured. In general, verapamil, VR or VS treatment alone (80 μM) appreciably enhanced MTT absorbance although higher concentrations (VR or VS) slightly decreased MTT absorbance. Diltiazem (140 μM) markedly decreased MTT absorbance (40%) at 120 h. VR or VS treatment inhibited {sup 3}H-thymidine incorporation (24 h) and induced cytological alterations (i.e., karyokinesis, enhanced perinuclear MTT deposition, accumulated perinuclear “vacuoles”). TEM revealed perinuclear “vacuoles” to be aggregates of highly laminated and electron-dense vesicles resembling autophagosomes and lysosomes, respectively. Increased autophagosome activity was confirmed by a concentration-dependent increase in LC3-II formation by Western blotting and by increased perinuclear LC3-GFP{sup +} puncta in verapamil-treated VSMC. Verapamil stereoisomers appeared to decrease perinuclear mitochondrial density. These observations indicate that antiproliferative effects of verapamil stereoisomers are produced by enhanced mitochondrial damage and upregulated autophagy in VSMC. These effects are independent of CCB activity indicating a distinct mechanism of action that could be targeted for more efficacious anti

  6. Magnetosheath dynamic pressure enhancements: occurrence and typical properties

    Directory of Open Access Journals (Sweden)

    M. O. Archer

    2013-02-01

    Full Text Available The first comprehensive statistical study of large-amplitude (> 100% transient enhancements of the magnetosheath dynamic pressure reveals events of up to ~ 15 times the ambient dynamic pressure with durations up to 3 min and an average duration of around 30 s, predominantly downstream of the quasi-parallel shock. The dynamic pressure transients are most often dominated by velocity increases along with a small fractional increase in the density, though the velocity is generally only deflected by a few degrees. Superposed wavelet transforms of the magnetic field show that, whilst most enhancements exhibit changes in the magnetosheath magnetic field, the majority are not associated with changes in the Interplanetary Magnetic Field (IMF. However, there is a minority of enhancements that do appear to be associated with solar wind discontinuities which cannot be explained simply by random events. In general, it is found that during periods of magnetosheath dynamic pressure enhancements the IMF is steadier than usual. This suggests that a stable foreshock and hence foreshock structures or processes may be important in the generation of the majority of magnetosheath dynamic pressure enhancements.

  7. Antiproliferative and Antiangiogenic Effects of Punica granatum Juice (PGJ) in Multiple Myeloma (MM).

    Science.gov (United States)

    Tibullo, Daniele; Caporarello, Nunzia; Giallongo, Cesarina; Anfuso, Carmelina Daniela; Genovese, Claudia; Arlotta, Carmen; Puglisi, Fabrizio; Parrinello, Nunziatina L; Bramanti, Vincenzo; Romano, Alessandra; Lupo, Gabriella; Toscano, Valeria; Avola, Roberto; Brundo, Maria Violetta; Di Raimondo, Francesco; Raccuia, Salvatore Antonio

    2016-10-01

    Multiple myeloma (MM) is a clonal B-cell malignancy characterized by an accumulation of clonal plasma cells (PC) in the bone marrow (BM) leading to bone destruction and BM failure. Despite recent advances in pharmacological therapy, MM remains a largely incurable pathology. Therefore, novel effective and less toxic agents are urgently necessary. In the last few years, pomegranate has been studied for its potential therapeutic properties including treatment and prevention of cancer. Pomegranate juice (PGJ) contains a number of potential active compounds including organic acids, vitamins, sugars, and phenolic components that are all responsible of the pro-apoptotic effects observed in tumor cell line. The aim of present investigation is to assess the antiproliferative and antiangiogenic potential of the PGJ in human multiple myeloma cell lines. Our data demonstrate the anti-proliferative potential of PGJ in MM cells; its ability to induce G0/G1 cell cycle block and its anti-angiogenic effects. Interestingly, sequential combination of bortezomib/PGJ improved the cytotoxic effect of the proteosome inhibitor. We investigated the effect of PGJ on angiogenesis and cell migration/invasion. Interestingly, we observed an inhibitory effect on the tube formation, microvessel outgrowth aorting ring and decreased cell migration and invasion as showed by wound-healing and transwell assays, respectively. Analysis of angiogenic genes expression in endothelial cells confirmed the anti-angiogenic properties of pomegranate. Therefore, PGJ administration could represent a good tool in order to identify novel therapeutic strategies for MM treatment, exploiting its anti-proliferative and anti-angiogenic effects. Finally, the present research supports the evidence that PGJ could play a key role of a future therapeutic approach for treatment of MM in order to optimize the pharmacological effect of bortezomib, especially as adjuvant after treatment.

  8. Antiproliferative and Antiangiogenic Effects of Punica granatum Juice (PGJ in Multiple Myeloma (MM

    Directory of Open Access Journals (Sweden)

    Daniele Tibullo

    2016-10-01

    Full Text Available Multiple myeloma (MM is a clonal B-cell malignancy characterized by an accumulation of clonal plasma cells (PC in the bone marrow (BM leading to bone destruction and BM failure. Despite recent advances in pharmacological therapy, MM remains a largely incurable pathology. Therefore, novel effective and less toxic agents are urgently necessary. In the last few years, pomegranate has been studied for its potential therapeutic properties including treatment and prevention of cancer. Pomegranate juice (PGJ contains a number of potential active compounds including organic acids, vitamins, sugars, and phenolic components that are all responsible of the pro-apoptotic effects observed in tumor cell line. The aim of present investigation is to assess the antiproliferative and antiangiogenic potential of the PGJ in human multiple myeloma cell lines. Our data demonstrate the anti-proliferative potential of PGJ in MM cells; its ability to induce G0/G1 cell cycle block and its anti-angiogenic effects. Interestingly, sequential combination of bortezomib/PGJ improved the cytotoxic effect of the proteosome inhibitor. We investigated the effect of PGJ on angiogenesis and cell migration/invasion. Interestingly, we observed an inhibitory effect on the tube formation, microvessel outgrowth aorting ring and decreased cell migration and invasion as showed by wound-healing and transwell assays, respectively. Analysis of angiogenic genes expression in endothelial cells confirmed the anti-angiogenic properties of pomegranate. Therefore, PGJ administration could represent a good tool in order to identify novel therapeutic strategies for MM treatment, exploiting its anti-proliferative and anti-angiogenic effects. Finally, the present research supports the evidence that PGJ could play a key role of a future therapeutic approach for treatment of MM in order to optimize the pharmacological effect of bortezomib, especially as adjuvant after treatment.

  9. Antiproliferative, Cytotoxic, Antioxidant Activity and Polyphenols Contents in Leaves of Four Staphylea L. Species

    Directory of Open Access Journals (Sweden)

    Daniel Grancai

    2009-08-01

    Full Text Available Staphylea has been used for long time in Traditional Chinese Medicine (TCM and by Native Americans in a number of therapeutical indications. The present study describes in vitro antiproliferative, cytotoxic properties (MTT and LDH test and antioxidant activities (reduction of DPPH radical and peroxynitrite radical of Staphylea colchica Stev. (SC, S. elegans Zab. (SC, S. holocarpa Hemsl. (SH and S. pinnata L. (SP leave water extracts. Time- (24 and 72 h and dose- (1-150 μg/mL dependent effects of the above extracts were tested at the mitochondrial (MTT test and plasma membrane level (LDH leakage in A431 human skin carcinoma cells. Screening of these properties has shown time and dose dependent increase of harmful effects, the highest activity was observed for the SE, while the less active was the SH extract. The ED50 values for the mitochondrial and membrane damage were nearly identical for the SE and very similar for SH extract. These findings indicate simultaneous injury of both cell compartments by SE and SH extracts. The highest antioxidant potential of SE species is accompanied by the highest content of flavones/flavonols and polyphenols. Only flavonoid contents are associated with antiproliferative effects and cell membrane injury, while antioxidant properties are the result of polyphenol content. The data clearly demonstrate that individual Staphylea L. species differ, not only in the amount of biologically active compounds, but also by the extent of harmful and beneficial effects.

  10. Antiproliferative activity of flavonoids on several cancer cell lines.

    Science.gov (United States)

    Kawaii, S; Tomono, Y; Katase, E; Ogawa, K; Yano, M

    1999-05-01

    Twenty-seven Citrus flavonoids were examined for their antiproliferative activities against several tumor and normal human cell lines. As a result, 7 flavonoids were judged to be active against the tumor cell lines, while they had weak antiproliferative activity against the normal human cell lines. The rank order of potency was luteolin, natsudaidain, quercetin, tangeretin, eriodictyol, nobiletin, and 3,3',4',5,6,7,8-heptamethoxyflavone. The structure-activity relationship established from comparison among these flavones and flavanones showed that the ortho-catechol moiety in ring B and a C2-C3 double bond were important for the antiproliferative activity. As to polymethoxylated flavones, C-3 hydroxyl and C-8 methoxyl groups were essential for high activity.

  11. Superfocusing properties of disorder-enhanced plasmonic nanolenses

    KAUST Repository

    Gongora, J. S. Totero; Coluccio, Maria Laura; Proietti Zaccaria, Remo; Di Fabrizio, Enzo M.; Fratalocchi, Andrea

    2014-01-01

    We investigated a disordered plasmonic nanolens using an extensive campaign of FDTD simulations. Our results show that surface roughness plays a crucial role in the enhancement of the electromagnetic energy with respect to regular structures. © 2014 Optical Society of America.

  12. Nitrogen doped germania glasses with enhanced optical and mechanical properties

    DEFF Research Database (Denmark)

    Storgaard-Larsen, Torben; Poulsen, Christian; Leistiko, Otto

    1997-01-01

    A new type of ultraviolet photosensitive germanium doped glass has been developed for use in the fabrication of optical waveguide structures. By adding ammonia to the source gases during a plasma enhanced chemical vapor deposition of these glasses, ultraviolet induced refractive index changes of ...

  13. Membranes with Surface-Enhanced Antifouling Properties for Water Purification

    Science.gov (United States)

    Shahkaramipour, Nima; Tran, Thien N.; Ramanan, Sankara; Lin, Haiqing

    2017-01-01

    Membrane technology has emerged as an attractive approach for water purification, while mitigation of fouling is key to lower membrane operating costs. This article reviews various materials with antifouling properties that can be coated or grafted onto the membrane surface to improve the antifouling properties of the membranes and thus, retain high water permeance. These materials can be separated into three categories, hydrophilic materials, such as poly(ethylene glycol), polydopamine and zwitterions, hydrophobic materials, such as fluoropolymers, and amphiphilic materials. The states of water in these materials and the mechanisms for the antifouling properties are discussed. The corresponding approaches to coat or graft these materials on the membrane surface are reviewed, and the materials with promising performance are highlighted. PMID:28273869

  14. A peroxisome proliferator-activated receptor ligand MCC-555 imparts anti-proliferative response in pancreatic cancer cells by PPARgamma-independent up-regulation of KLF4

    Energy Technology Data Exchange (ETDEWEB)

    Min, Kyung-Won [Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996 (United States); Zhang, Xiaobo [Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996 (United States); College of Animal Science and Technology, Northwest A and F University, Yangling, Shaanxi, 712100 (China); Imchen, Temjenmongla [Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996 (United States); Baek, Seung Joon, E-mail: sbaek2@utk.edu [Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996 (United States)

    2012-09-01

    MCC-555 is a novel PPARα/γ dual ligand of the thiazolidinedione class and was recently developed as an anti-diabetic drug with unique properties. MCC-555 also has anti-proliferative activity through growth inhibition and apoptosis induction in several cancer cell types. Our group has shown that MCC-555 targets several proteins in colorectal tumorigenesis including nonsteroidal anti-inflammatory drug (NSAID)-activated gene (NAG-1) which plays an important role in chemoprevention responsible for chemopreventive compounds. NAG-1 is a member of the TGF-β superfamily and is involved in tumor progression and development; however, NAG-1's roles in pancreatic cancer have not been studied. In this report, we found that MCC-555 alters not only NAG-1 expression, but also p21 and cyclin D1 expression. NAG-1 and p21 expression was not blocked by PPARγ-specific antagonist GW9662, suggesting that MCC-555-induced NAG-1 and p21 expression is independent of PPARγ activation. However, decreasing cyclin D1 by MCC-555 seems to be affected by PPARγ activation. Further, we found that the GC box located in the NAG-1 promoter play an important role in NAG-1 transactivation by MCC-555. Subsequently, we screened several transcription factors that may bind to the GC box region in the NAG-1 promoter and found that KLF4 potentially binds to this region. Expression of KLF4 precedes NAG-1 and p21 expression in the presence of MCC-555, whereas blocking KLF4 expression using specific KLF4 siRNA showed that both NAG-1 and p21 expression by MCC-555 was blocked. In conclusion, MCC-555's actions on anti-proliferation involve both PPARγ-dependent and -independent pathways, thereby enhancing anti-tumorigenesis in pancreatic cancer cells. -- Highlights: ► PPARα/γ ligand MCC-555 exhibits anti-proliferative activity in pancreatic cancer cells. ► MCC-555 affects KLF4 expression following by NAG-1 and p21 expression in a PPARγ independent manner. ► MCC-555 also affects cyclin D1 down

  15. A peroxisome proliferator-activated receptor ligand MCC-555 imparts anti-proliferative response in pancreatic cancer cells by PPARgamma-independent up-regulation of KLF4

    International Nuclear Information System (INIS)

    Min, Kyung-Won; Zhang, Xiaobo; Imchen, Temjenmongla; Baek, Seung Joon

    2012-01-01

    MCC-555 is a novel PPARα/γ dual ligand of the thiazolidinedione class and was recently developed as an anti-diabetic drug with unique properties. MCC-555 also has anti-proliferative activity through growth inhibition and apoptosis induction in several cancer cell types. Our group has shown that MCC-555 targets several proteins in colorectal tumorigenesis including nonsteroidal anti-inflammatory drug (NSAID)-activated gene (NAG-1) which plays an important role in chemoprevention responsible for chemopreventive compounds. NAG-1 is a member of the TGF-β superfamily and is involved in tumor progression and development; however, NAG-1's roles in pancreatic cancer have not been studied. In this report, we found that MCC-555 alters not only NAG-1 expression, but also p21 and cyclin D1 expression. NAG-1 and p21 expression was not blocked by PPARγ-specific antagonist GW9662, suggesting that MCC-555-induced NAG-1 and p21 expression is independent of PPARγ activation. However, decreasing cyclin D1 by MCC-555 seems to be affected by PPARγ activation. Further, we found that the GC box located in the NAG-1 promoter play an important role in NAG-1 transactivation by MCC-555. Subsequently, we screened several transcription factors that may bind to the GC box region in the NAG-1 promoter and found that KLF4 potentially binds to this region. Expression of KLF4 precedes NAG-1 and p21 expression in the presence of MCC-555, whereas blocking KLF4 expression using specific KLF4 siRNA showed that both NAG-1 and p21 expression by MCC-555 was blocked. In conclusion, MCC-555's actions on anti-proliferation involve both PPARγ-dependent and -independent pathways, thereby enhancing anti-tumorigenesis in pancreatic cancer cells. -- Highlights: ► PPARα/γ ligand MCC-555 exhibits anti-proliferative activity in pancreatic cancer cells. ► MCC-555 affects KLF4 expression following by NAG-1 and p21 expression in a PPARγ independent manner. ► MCC-555 also affects cyclin D1 down

  16. Two approaches for enhancing the hydrogenation properties of ...

    Indian Academy of Sciences (India)

    Wintec

    ties of Pd. In the first approach, metal thin film (Cu, Ag) has been deposited over Pd and hydrogenation properties of ... Firstly, the critical temperature of miscibility gap for the α to β phase ... diffraction (GAXRD) studies have been done. 18. The.

  17. Enhanced properties of UPE/ESOA partially bio-nanocomposites ...

    Indian Academy of Sciences (India)

    59

    Epoxidized Soybean Oil Acrylate (ESOA) to recuperate its performance. .... Tensile properties were evaluated by using the universal testing machine (Model 3369) in .... carboxyl band at 1670cm-1 which are essential for making reaction with ..... increased hours of NaCl treatment, very small weight was gained in all the ...

  18. Antiproliferative activity of synthetic fatty acid amides from renewable resources.

    Science.gov (United States)

    dos Santos, Daiane S; Piovesan, Luciana A; D'Oca, Caroline R Montes; Hack, Carolina R Lopes; Treptow, Tamara G M; Rodrigues, Marieli O; Vendramini-Costa, Débora B; Ruiz, Ana Lucia T G; de Carvalho, João Ernesto; D'Oca, Marcelo G Montes

    2015-01-15

    In the work, the in vitro antiproliferative activity of a series of synthetic fatty acid amides were investigated in seven cancer cell lines. The study revealed that most of the compounds showed antiproliferative activity against tested tumor cell lines, mainly on human glioma cells (U251) and human ovarian cancer cells with a multiple drug-resistant phenotype (NCI-ADR/RES). In addition, the fatty methyl benzylamide derived from ricinoleic acid (with the fatty acid obtained from castor oil, a renewable resource) showed a high selectivity with potent growth inhibition and cell death for the glioma cell line-the most aggressive CNS cancer. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. The antiproliferative effect of coumarins on several cancer cell lines.

    Science.gov (United States)

    Kawaii, S; Tomono, Y; Ogawa, K; Sugiura, M; Yano, M; Yoshizawa, Y

    2001-01-01

    Twenty-one coumarins were examined for their antiproliferative activity towards several cancer cell lines, namely lung carcinoma (A549), melanin pigment producing mouse melanoma (B16 melanoma 4A5), human T-cell leukemia (CCRF-HSB-2), and human gastric cancer, lymph node metastasized (TGBC11TKB). The structure-activity relationship established from the results revealed that the 6,7-dihydroxy moiety had an important role for their antiproliferative activity. Analysis of cell cycle distribution indicated that esculetin-treated cells accumulated in the G1 (at 400 microM) or in S phase (at 100 microM).

  20. Design, Synthesis and Evaluation of Antiproliferative Activity of New Benzimidazolehydrazones

    Directory of Open Access Journals (Sweden)

    Valentina Onnis

    2016-04-01

    Full Text Available The synthesis and antiproliferative activity of new benzimidazole derivatives bearing an hydrazone mojety at the 2-position is described. The new N′-(4-arylidene-1H-benzo[d]imidazole-2-carbohydrazides were evaluated for their cytostatic activity toward the murine leukemia (L1210, human T-cell leukemia (CEM, human cervix carcinoma (HeLa and human pancreas carcinoma cells (Mia Paca-2. A preliminary structure-activity relationship could be defined. Some of the compounds possess encouraging and consistent antiproliferative activity, having IC50 values in the low micromolar range.

  1. Real-time observations of mechanical stimulus-induced enhancements of mechanical properties in osteoblast cells

    International Nuclear Information System (INIS)

    Zhang Xu; Liu Xiaoli; Sun Jialun; He Shuojie; Lee, Imshik; Pak, Hyuk Kyu

    2008-01-01

    Osteoblast, playing a key role in the pathophysiology of osteoporosis, is one of the mechanical stress sensitive cells. The effects of mechanical load-induced changes of mechanical properties in osteoblast cells were studied at real-time. Osteoblasts obtained from young Wister rats were exposed to mechanical loads in different frequencies and resting intervals generated by atomic force microscopy (AFM) probe tip and simultaneously measured the changes of the mechanical properties by AFM. The enhancement of the mechanical properties was observed and quantified by the increment of the apparent Young's modulus, E * . The observed mechanical property depended on the frequency of applied tapping loads. For the resting interval is 50 s, the mechanical load-induced enhancement of E * -values disappears. It seems that the enhanced mechanical property was recover able under no additional mechanical stimulus

  2. Novel Antitumor Platinum(II) Conjugates Containing the Nonsteroidal Anti-inflammatory Agent Diclofenac: Synthesis and Dual Mechanisms of Antiproliferative Effects.

    Science.gov (United States)

    Intini, Francesco Paolo; Zajac, Juraj; Novohradsky, Vojtech; Saltarella, Teresa; Pacifico, Concetta; Brabec, Viktor; Natile, Giovanni; Kasparkova, Jana

    2017-02-06

    One concept how to improve anticancer effects of conventional metallodrugs consists in conjugation of these compounds with other biologically (antitumor) active agents, acting by a different mechanism. Here, we present synthesis, biological effects, and mechanisms of action of new Pt(II) derivatives containing one or two nonsteroidal anti-inflammatory diclofenac (DCF) ligands also known for their antitumor effects. The antiproliferative properties of these metallic conjugates show that these compounds are potent and cancer cell selective cytotoxic agents exhibiting activity in cisplatin resistant and the COX-2 positive tumor cell lines. One of these compounds, compound 3, in which DCF molecules are coordinated to Pt(II) through their carboxylic group, is more potent than parental conventional Pt(II) drug cisplatin, free DCF and the congeners of 3 in which DCF ligands are conjugated to Pt(II) via a diamine. The potency of 3 is due to several factors including enhanced internalization that correlates with enhanced DNA binding and cytotoxicity. Mechanistic studies show that 3 combines multiple effects. After its accumulation in cells, it releases Pt(II) drug capable of binding/damaging DNA and DCF ligands, which affect distribution of cells in individual phases of the cell cycle, inhibit glycolysis and lactate transport, collapse mitochondrial membrane potential, and suppress the cellular properties characteristic of metastatic progression.

  3. Enhanced properties of graphene/fly ash geopolymeric composite cement

    Energy Technology Data Exchange (ETDEWEB)

    Saafi, Mohamed, E-mail: m.bensalem.saafi@strath.ac.uk [Department of Civil and Environmental Engineering, University of Strathclyde, G4 0NG (United Kingdom); Tang, Leung [Agilent Technologies, EH12 9DJ (United Kingdom); Fung, Jason; Rahman, Mahbubur [Department of Civil and Environmental Engineering, University of Strathclyde, G4 0NG (United Kingdom); Liggat, John [Department of Pure and Applied Chemistry, University of Strathclyde, G4 0NG (United Kingdom)

    2015-01-15

    This paper reports for the first time the incorporation of in-situ reduced graphene oxide (rGO) into geopolymers. The resulting rGO–geopolymeric composites are easy to manufacture and exhibit excellent mechanical properties. Geopolymers with graphene oxide (GO) concentrations of 0.00, 0.10, 0.35 and 0.50% by weight were fabricated. The functional groups, morphology, void filling mechanisms and mechanical properties of the composites were determined. The Fourier transform infrared (FTIR) spectra revealed that the alkaline solution reduced the hydroxyl/carbonyl groups of GO by deoxygenation and/or dehydration. Concomitantly, the spectral absorbance related to silica type cross-linking increased in the spectra. The scanning electron microscope (SEM) micrographs indicated that rGO altered the morphology of geopolymers from a porous nature to a substantially pore filled morphology with increased mechanical properties. The flexural tests showed that 0.35-wt.% rGO produced the highest flexural strength, Young's modulus and flexural toughness and they were increased by 134%, 376% and 56%, respectively.

  4. Synthesis, Antiproliferative, and Multidrug Resistance Reversal Activities of Heterocyclic α,β-Unsaturated Carbonyl Compounds.

    Science.gov (United States)

    Sun, Ju-Feng; Hou, Gui-Ge; Zhao, Feng; Cong, Wei; Li, Hong-Juan; Liu, Wen-Shuai; Wang, Chunhua

    2016-10-01

    A series of heterocyclic α,β-unsaturated carbonyl compounds (1a-1d, 2a-2d, 3a-3d, 4a-3d, and 5a-5d) with 1,5-diaryl-3-oxo-1,4-pentadienyl pharmacophore were synthesized for the development of anticancer and multidrug resistance reverting agents. The antiproliferative activities were tested against nine human cancer cell lines. Approximately 73% of the IC50 values were below 5 μm, while 35% of these figures were submicromolar, and compounds 3a-3d with 4-trifluoro methyl in the arylidene benzene rings were the most potent, since their IC50 values are between 0.06 and 3.09 μm against all cancer cell lines employed. Meanwhile, their multidrug resistance reversal properties and cellular uptake were further examined. The data displayed that all of these compounds could reverse multidrug resistance, particularly, compounds 3a and 4a demonstrated both potent multidrug resistance reverting properties and strong antiproliferative activities, which can be taken as leading molecules for further research of dual effect agents in tumor chemotherapy. © 2016 John Wiley & Sons A/S.

  5. In vitro biological screening of the anticholinesterase and antiproliferative activities of medicinal plants belonging to Annonaceae

    International Nuclear Information System (INIS)

    Formagio, A.S.N.; Vieira, M.C.; Volobuff, C.R.F.; Silva, M.S.; Matos, A.I.; Cardoso, C.A.L.; Foglio, M.A.; Carvalho, J.E.

    2015-01-01

    The aim of this research was to investigate the antiproliferative and anticholinesterase activities of 11 extracts from 5 Annonaceae species in vitro. Antiproliferative activity was assessed using 10 human cancer cell lines. Thin-layer chromatography and a microplate assay were used to screen the extracts for acetylcholinesterase (AchE) inhibitors using Ellman's reagent. The chemical compositions of the active extracts were investigated using high performance liquid chromatography. Eleven extracts obtained from five Annonaceae plant species were active and were particularly effective against the UA251, NCI-470 lung, HT-29, NCI/ADR, and K-562 cell lines with growth inhibition (GI 50 ) values of 0.04-0.06, 0.02-0.50, 0.01-0.12, 0.10-0.27, and 0.02-0.04 µg/mL, respectively. In addition, the Annona crassiflora and A. coriacea seed extracts were the most active among the tested extracts and the most effective against the tumor cell lines, with GI 50 values below 8.90 µg/mL. The A. cacans extract displayed the lowest activity. Based on the microplate assay, the percent AchE inhibition of the extracts ranged from 12 to 52%, and the A. coriacea seed extract resulted in the greatest inhibition (52%). Caffeic acid, sinapic acid, and rutin were present at higher concentrations in the A. crassiflora seed samples. The A. coriacea seeds contained ferulic and sinapic acid. Overall, the results indicated that A. crassiflora and A. coriacea extracts have antiproliferative and anticholinesterase properties, which opens up new possibilities for alternative pharmacotherapy drugs

  6. Kinetics Extraction Modelling and Antiproliferative Activity of Clinacanthus nutans Water Extract

    Directory of Open Access Journals (Sweden)

    Farah Nadiah Mohd Fazil

    2016-01-01

    Full Text Available Clinacanthus nutans is widely grown in tropical Asia and locally known “belalai gajah” or Sabah snake grass. It has been used as a natural product to treat skin rashes, snake bites, lesion caused by herpes, diabetes, fever, and cancer. Therefore, the objectives of this research are to determine the maximum yield and time of exhaustive flavonoids extraction using Peleg’s model and to evaluate potential of antiproliferative activity on human lung cancer cell (A549. The extraction process was carried out on fresh and dried leaves at 28 to 30°C with liquid-to-solid ratio of 10 mL/g for 72 hrs. The extracts were collected intermittently analysed using mathematical Peleg’s model and RP-HPLC. The highest amount of flavonoids was used to evaluate the inhibitory concentration (IC50 via 2D cell culture of A549. Based on the results obtained, the predicted maximum extract density was observed at 29.20 ± 14.54 hrs of extraction (texhaustive. However, the exhaustive time of extraction to acquire maximum flavonoids content exhibited approximately 10 hrs earlier. Therefore, 18 hrs of extraction time was chosen to acquire high content of flavonoids. The best antiproliferative effect (IC50 on A549 cell line was observed at 138.82 ± 0.60 µg/mL. In conclusion, the flavonoids content in Clinacanthus nutans water extract possesses potential antiproliferative properties against A549, suggesting an alternative approach for cancer treatment.

  7. In vitro biological screening of the anticholinesterase and antiproliferative activities of medicinal plants belonging to Annonaceae

    Energy Technology Data Exchange (ETDEWEB)

    Formagio, A.S.N.; Vieira, M.C. [Faculdade de Ciências Agrárias, Universidade Federal da Grande Dourados, Dourados, MS (Brazil); Volobuff, C.R.F.; Silva, M.S. [Faculdade de Ciências Biológicas e Ambientais, Universidade Federal da Grande Dourados, Dourados, MS (Brazil); Matos, A.I. [Faculdade de Ciências, Universidade de Lisboa, Lisboa (Portugal); Cardoso, C.A.L. [Curso de Química, Universidade Estadual do Mato Grosso do Sul, Dourados, MS (Brazil); Foglio, M.A.; Carvalho, J.E. [Centro Pluridisciplinar de Pesquisas Químicas, Biológicas e Agrícolas, Universidade Estadual de Campinas, Campinas, SP (Brazil)

    2015-02-13

    The aim of this research was to investigate the antiproliferative and anticholinesterase activities of 11 extracts from 5 Annonaceae species in vitro. Antiproliferative activity was assessed using 10 human cancer cell lines. Thin-layer chromatography and a microplate assay were used to screen the extracts for acetylcholinesterase (AchE) inhibitors using Ellman's reagent. The chemical compositions of the active extracts were investigated using high performance liquid chromatography. Eleven extracts obtained from five Annonaceae plant species were active and were particularly effective against the UA251, NCI-470 lung, HT-29, NCI/ADR, and K-562 cell lines with growth inhibition (GI{sub 50}) values of 0.04-0.06, 0.02-0.50, 0.01-0.12, 0.10-0.27, and 0.02-0.04 µg/mL, respectively. In addition, the Annona crassiflora and A. coriacea seed extracts were the most active among the tested extracts and the most effective against the tumor cell lines, with GI{sub 50} values below 8.90 µg/mL. The A. cacans extract displayed the lowest activity. Based on the microplate assay, the percent AchE inhibition of the extracts ranged from 12 to 52%, and the A. coriacea seed extract resulted in the greatest inhibition (52%). Caffeic acid, sinapic acid, and rutin were present at higher concentrations in the A. crassiflora seed samples. The A. coriacea seeds contained ferulic and sinapic acid. Overall, the results indicated that A. crassiflora and A. coriacea extracts have antiproliferative and anticholinesterase properties, which opens up new possibilities for alternative pharmacotherapy drugs.

  8. Enhancement of Unequal Error Protection Properties of LDPC Codes

    Directory of Open Access Journals (Sweden)

    Poulliat Charly

    2007-01-01

    Full Text Available It has been widely recognized in the literature that irregular low-density parity-check (LDPC codes exhibit naturally an unequal error protection (UEP behavior. In this paper, we propose a general method to emphasize and control the UEP properties of LDPC codes. The method is based on a hierarchical optimization of the bit node irregularity profile for each sensitivity class within the codeword by maximizing the average bit node degree while guaranteeing a minimum degree as high as possible. We show that this optimization strategy is efficient, since the codes that we optimize show better UEP capabilities than the codes optimized for the additive white Gaussian noise channel.

  9. Stretchable polyurethane sponge reinforced magnetorheological material with enhanced mechanical properties

    International Nuclear Information System (INIS)

    Ge, Lin; Xuan, Shouhu; Liao, Guojiang; Yin, Tiantian; Gong, Xinglong

    2015-01-01

    A stretchable magnetorheological material (SMRM) consisting of micro-meter carbonyl iron (CI) particles, low cross-linking polyurethane (PU) polymer and porous PU sponge has been developed. Due to the presence of the PU sponge, the high-performance MR material can be reversibly stretched or bent, just as MR elastomers. When the CI content increases to 80 wt%, the magnetic induced modulus of the MR material can reach as high as 7.34 MPa and the corresponding relative MR effect increases to 820%. A possible strengthening mechanism of the SMRM was proposed. The attractive mechanical properties make the SMRM a promising candidate for future high-performance devices. (technical note)

  10. Enhancing mechanical properties of chitosan films via modification with vanillin.

    Science.gov (United States)

    Zhang, Zhi-Hong; Han, Zhong; Zeng, Xin-An; Xiong, Xia-Yu; Liu, Yu-Jia

    2015-11-01

    The vanillin/chitosan composite films were prepared using the solvent evaporation method. The properties of the films including optical property, water vapor permeability (WVP), tensile strength (TS) and elongation at break (%E) were studied to investigate the effect of cross-linking agent of vanillin on chitosan films by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectrum (FT-IR). Results showed that the TS of composite films increased by 53.3% and the WVP decreased by 36.5% compared with pure chitosan film that were due to the formation of the dense network structure by FT-IR spectra. There were almost no changes of the thermal stability of the composite films compared with the pure chitosan film by TGA analysis. In addition, from the SEM images, it could be seen that the film with addition of vanillin with 0.5-10% concentration exhibited good compatibility. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Crumb Rubber Recycling in Enhancing Damping Properties of Concrete

    Science.gov (United States)

    Sugapriya, P.; Ramkrishnan, R.

    2018-02-01

    Damping plays a major role in the design of roadside structures that gets affected due to vibrations transmitted from moving traffic. In this study, fine aggregates were partially replaced with crumb rubber in concrete, at varying percentages of 5, 10, 15 and 20% by weight. Three different sets of concrete, mixed with crumb rubber were prepared using raw rubber, treated rubber and treated rubber with partial replacement of cement. Cement was partially replaced with Ultra-Fine Ground Granulated Blast furnace Slag (UFGGBS) for this study. Samples were cast, cured and tested for various properties on the 7th and 28th day. The damping ratio and frequency of the peak value from a number of waves in rubber incorporated beams were found out using a FFT Analyser along with its Strength, Damping and Sorptivity characteristics. SEM analysis was conducted to analyse the micro structural bonding between rubber and concrete. The mode shapes of pavement slabs were modelled and analysed using a FEM tool, ANSYS. From the results, the behaviour of the three sets of rubberized concrete were compared and analysed, and an optimum percentage for crumb rubber and UFGGBS was proposed to achieve best possible damping without compromising the strength properties.

  12. Enhancement of properties of recycled coarse aggregate concrete using bacteria

    Science.gov (United States)

    Sahoo; Arakha; Sarkar; P; Jha

    2016-01-01

    Due to rapid construction, necessity for raw materials of concrete, especially coarse aggregate, tends to increase the danger of early exhaustion of the natural resources. An alternative source of raw materials would perhaps delay the advent of this early exhaustion. Recycled coarse aggregate (RCA) plays a great role as an alternative raw material that can replace the natural coarse aggregate (NCA) for concrete. Previous studies show that the properties of RCA concrete are inferior in quality compared to NCA concrete. This article attempts to study the improvement of properties of RCA concrete with the addition of bacteria named as Bacillus subtilis. The experimental investigation was carried out to evaluate the improvement of the compressive strength, capillary water absorption, and drying shrinkage of RCA concrete incorporating bacteria. The compressive strength of RCA concrete is found to be increased by about 20% when the cell concentration of B. subtilis is 106 cells/ml. The capillary water absorption as well as drying shrinkage of RCA are reduced when bacteria is incorporated. The improvement of RCA concrete is confirmed to be due to the calcium carbonate precipitation as observed from the microstructure studies carried out on it such as EDX, SEM, and XRD.

  13. Anti-proliferative effect of Moringa oleifera Lam (Moringaceae) leaf ...

    African Journals Online (AJOL)

    Purpose: To investigate the in vitro anti-proliferative effect and mechanism of action of Moringa oleifera Lam. leaf extract on human colon carcinoma HCT116 cell line. Methods: M. oleifera leaves were extracted with methanol. It was fractionated by Sephadex LH-20 column chromatography. Several fractions were identified ...

  14. Evaluation of the anti-proliferative and cytotoxic potentials of ...

    African Journals Online (AJOL)

    The partitioned aqueous and chloroform fractions obtained from the methanol extract of the leaf of Cnidoscolus aconitifolius were examined for anti-proliferative (1-30 mg/mL) and cytotoxic activities (20-400 μg/mL) using the seed radicle inhibition and tadpole mortality assays over a period of 24 and 96 h respectively.

  15. Antimicrobial and antiproliferative activities of stingless bee Melipona scutellaris geopropolis

    OpenAIRE

    da Cunha, Marcos Guilherme; Franchin, Marcelo; Galv?o, L?viaC?maradeCarvalho; de Ruiz, AnaL?ciaTascaG?is; de Carvalho, Jo?o Ernesto; Ikegaki, Masarahu; de Alencar, Severino Matias; Koo, Hyun; Rosalen, Pedro Luiz

    2013-01-01

    Abstract Background Geopropolis is a type of propolis containing resin, wax, and soil, collected by threatened stingless bee species native to tropical countries and used in folk medicine. However, studies concerning the biological activity and chemical composition of geopropolis are scarce. In this study, we evaluated the antimicrobial and antiproliferative activity of the ethanolic extract of geopropolis (EEGP) collected by Melipona sc...

  16. Anti-proliferative activity of recombinant melittin expressed in ...

    African Journals Online (AJOL)

    Recombinant melittin was then successfully expressed in Escherichia coli. The activity of affinity-purified recombinant melittin was determined in human leukemic U937 cells. Results show that the recombinant melittin had the same anti-proliferative activity in human leukemic U937 cells in vitro as natural one. This shows the ...

  17. Antiproliferative activity of recombinant human interferon-λ2 ...

    African Journals Online (AJOL)

    Jane

    2011-07-20

    Jul 20, 2011 ... antiviral activity, antiproliferative activity and in vivo antitumor activity .... bovine serum albumin (BSA) and 0.05% (v/v) Tween 20 in PBS at room temperature for 1 h .... identified and developed into an important insect embryo.

  18. Evaluation of Antiproliferative Activity of Some Traditional Anticancer ...

    African Journals Online (AJOL)

    antiproliferative activity against six human tumor cell lines (A375.S2, WM1361A, CACO-2, ... presence of cancer therapy-related problems. ... Table 1: Characteristics of the plants investigated in this study ... of cell viability using MTT (3-(4, 5-.

  19. Antiproliferative Activity of Some Medicinal Plants on Human Breast ...

    African Journals Online (AJOL)

    Methods: The aerial parts of the plants were successively extracted with hexane, dichloromethane, methanol and ... plants by high performance liquid chromatography (HPLC) while their antiproliferative activity was ... seeds and flavonoid glycosides in the aerial parts. [23]. .... In the present study, quantification of the chosen.

  20. Antioxidant and Anti-proliferative Activities of Flavonoids from ...

    African Journals Online (AJOL)

    Purpose: To investigate the chemical composition of Bidens pilosa L. var. radiata. Sch Bip. (BP), as well as its antioxidant and anti-proliferative activities. Methods: The whole herb of BP was extracted with 95 % ethanol, which was then partitioned sequentially with petroleum ether, ethyl acetate and n-butyl alcohol to obtain ...

  1. Synthesis, antiproliferative and antibacterial activity of new amides of salinomycin.

    Science.gov (United States)

    Antoszczak, Michał; Maj, Ewa; Stefańska, Joanna; Wietrzyk, Joanna; Janczak, Jan; Brzezinski, Bogumil; Huczyński, Adam

    2014-04-01

    A series of 11 novel amides of salinomycin were synthesized for the first time. All the obtained compounds were found to show potent antiproliferative activity against human cancer cell lines including the drug-resistant cancer cells. Four new salinomycin derivatives revealed good antibacterial activity against clinical isolates of methicillin-resistant Staphylococcus epidermidis (MRSE). Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Antiproliferative activity of some novel platinum complexes on C6 ...

    African Journals Online (AJOL)

    MCF-7) and glioma cells (C6). IC50 values of the three compounds were lower in the cisplatin-resistant cell type C6 cell lines than in MCF-7 cells. Key words: Cisplatin, antiproliferative activity, breast cancer cells (MCF-7), glioma cells (C6), IC50.

  3. Discovery of Selective Phosphodiesterase 1 Inhibitors with Memory Enhancing Properties.

    Science.gov (United States)

    Dyck, Brian; Branstetter, Bryan; Gharbaoui, Tawfik; Hudson, Andrew R; Breitenbucher, J Guy; Gomez, Laurent; Botrous, Iriny; Marrone, Tami; Barido, Richard; Allerston, Charles K; Cedervall, E Peder; Xu, Rui; Sridhar, Vandana; Barker, Ryan; Aertgeerts, Kathleen; Schmelzer, Kara; Neul, David; Lee, Dong; Massari, Mark Eben; Andersen, Carsten B; Sebring, Kristen; Zhou, Xianbo; Petroski, Robert; Limberis, James; Augustin, Martin; Chun, Lawrence E; Edwards, Thomas E; Peters, Marco; Tabatabaei, Ali

    2017-04-27

    A series of potent thienotriazolopyrimidinone-based PDE1 inhibitors was discovered. X-ray crystal structures of example compounds from this series in complex with the catalytic domain of PDE1B and PDE10A were determined, allowing optimization of PDE1B potency and PDE selectivity. Reduction of hERG affinity led to greater than a 3000-fold selectivity for PDE1B over hERG. 6-(4-Methoxybenzyl)-9-((tetrahydro-2H-pyran-4-yl)methyl)-8,9,10,11-tetrahydropyrido[4',3':4,5]thieno[3,2-e][1,2,4]triazolo[1,5-c]pyrimidin-5(6H)-one was identified as an orally bioavailable and brain penetrating PDE1B enzyme inhibitor with potent memory-enhancing effects in a rat model of object recognition memory.

  4. Enhancement of strength properties of hot rolled 10KHSND steel

    International Nuclear Information System (INIS)

    Nasibov, A.G.; Popova, L.V.; Pikulin, S.A.; Globa, N.I.

    1989-01-01

    To find out the reasons of low hot rolling yield for 10KhSND steel sheets in mechanical properties, titanium effect in the range of 0.008-0.03% concentrations is studied. It is established that the titanium content in a solid solution is conserved within 0.003-0.005%, the rest of titanium is bound to carbonitrides Ti(C, N). It is shown that alloys with 0.025-0.03% titanium content possess the increased values of ultimate and yield strength the necessary level of impact strength and good wealdability. The good steel yield, when the titanium content is sustained at the given level, increases from 40 to 85%

  5. Enhancing the combustible properties of bamboo by torrefaction.

    Science.gov (United States)

    Rousset, Patrick; Aguiar, Clarissa; Labbé, Nicole; Commandré, Jean-Michel

    2011-09-01

    Bamboo has wide range of moisture content, low bulk energy density and is difficult to transport, handle, store and feed into existing combustion and gasification systems. Because of its important fuel characteristics such as low ash content, alkali index and heating value, bamboo is a promising energy crop for the future. The aim of this study was to evaluate the effects of torrefaction on the main energy properties of Bambusa vulgaris. Three different torrefaction temperatures were employed: 220, 250 and 280°C. The elemental characteristics of lignite and coal were compared to the torrefied bamboo. The characteristics of the biomass fuels tend toward those of low rank coals. Principal component analysis of FTIR data showed a clear separation between the samples by thermal treatment. The loadings plot indicated that the bamboo samples underwent chemical changes related to carbonyl groups, mostly present in hemicelluloses, and to aromatic groups present in lignin. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Nanostructured germanium deposited on heated substrates with enhanced photoelectric properties.

    Science.gov (United States)

    Stavarache, Ionel; Maraloiu, Valentin Adrian; Prepelita, Petronela; Iordache, Gheorghe

    2016-01-01

    Obtaining high-quality materials, based on nanocrystals, at low temperatures is one of the current challenges for opening new paths in improving and developing functional devices in nanoscale electronics and optoelectronics. Here we report a detailed investigation of the optimization of parameters for the in situ synthesis of thin films with high Ge content (50 %) into SiO 2 . Crystalline Ge nanoparticles were directly formed during co-deposition of SiO 2 and Ge on substrates at 300, 400 and 500 °C. Using this approach, effects related to Ge-Ge spacing are emphasized through a significant improvement of the spatial distribution of the Ge nanoparticles and by avoiding multi-step fabrication processes or Ge loss. The influence of the preparation conditions on structural, electrical and optical properties of the fabricated nanostructures was studied by X-ray diffraction, transmission electron microscopy, electrical measurements in dark or under illumination and response time investigations. Finally, we demonstrate the feasibility of the procedure by the means of an Al/n-Si/Ge:SiO 2 /ITO photodetector test structure. The structures, investigated at room temperature, show superior performance, high photoresponse gain, high responsivity (about 7 AW -1 ), fast response time (0.5 µs at 4 kHz) and great optoelectronic conversion efficiency of 900% in a wide operation bandwidth, from 450 to 1300 nm. The obtained photoresponse gain and the spectral width are attributed mainly to the high Ge content packed into a SiO 2 matrix showing the direct connection between synthesis and optical properties of the tested nanostructures. Our deposition approach put in evidence the great potential of Ge nanoparticles embedded in a SiO 2 matrix for hybrid integration, as they may be employed in structures and devices individually or with other materials, hence the possibility of fabricating various heterojunctions on Si, glass or flexible substrates for future development of Si

  7. Nanostructured germanium deposited on heated substrates with enhanced photoelectric properties

    Directory of Open Access Journals (Sweden)

    Ionel Stavarache

    2016-10-01

    Full Text Available Obtaining high-quality materials, based on nanocrystals, at low temperatures is one of the current challenges for opening new paths in improving and developing functional devices in nanoscale electronics and optoelectronics. Here we report a detailed investigation of the optimization of parameters for the in situ synthesis of thin films with high Ge content (50 % into SiO2. Crystalline Ge nanoparticles were directly formed during co-deposition of SiO2 and Ge on substrates at 300, 400 and 500 °C. Using this approach, effects related to Ge–Ge spacing are emphasized through a significant improvement of the spatial distribution of the Ge nanoparticles and by avoiding multi-step fabrication processes or Ge loss. The influence of the preparation conditions on structural, electrical and optical properties of the fabricated nanostructures was studied by X-ray diffraction, transmission electron microscopy, electrical measurements in dark or under illumination and response time investigations. Finally, we demonstrate the feasibility of the procedure by the means of an Al/n-Si/Ge:SiO2/ITO photodetector test structure. The structures, investigated at room temperature, show superior performance, high photoresponse gain, high responsivity (about 7 AW−1, fast response time (0.5 µs at 4 kHz and great optoelectronic conversion efficiency of 900% in a wide operation bandwidth, from 450 to 1300 nm. The obtained photoresponse gain and the spectral width are attributed mainly to the high Ge content packed into a SiO2 matrix showing the direct connection between synthesis and optical properties of the tested nanostructures. Our deposition approach put in evidence the great potential of Ge nanoparticles embedded in a SiO2 matrix for hybrid integration, as they may be employed in structures and devices individually or with other materials, hence the possibility of fabricating various heterojunctions on Si, glass or flexible substrates for future development of Si

  8. Bias-enhanced post-treatment process for enhancing the electron field emission properties of ultrananocrystalline diamond films

    International Nuclear Information System (INIS)

    Saravanan, A.; Huang, B. R.; Sankaran, K. J.; Tai, N. H.; Dong, C. L.; Lin, I. N.

    2015-01-01

    The electron field emission (EFE) properties of ultrananocrystalline diamond films were markedly improved via the bias-enhanced plasma post-treatment (bep) process. The bep-process induced the formation of hybrid-granular structure of the diamond (bep-HiD) films with abundant nano-graphitic phase along the grain boundaries that increased the conductivity of the films. Moreover, the utilization of Au-interlayer can effectively suppress the formation of resistive amorphous-carbon (a-C) layer, thereby enhancing the transport of electrons crossing the diamond-to-Si interface. Therefore, bep-HiD/Au/Si films exhibit superior EFE properties with low turn-on field of E 0  = 2.6 V/μm and large EFE current density of J e  = 3.2 mA/cm 2 (at 5.3 V/μm)

  9. Enhancement of Ultrahigh Performance Concrete Material Properties with Carbon Nanofiber

    Directory of Open Access Journals (Sweden)

    Libya Ahmed Sbia

    2014-01-01

    Full Text Available Ultrahigh performance concrete (UHPC realized distinctly high mechanical, impermeability, and durability characteristics by reducing the size and content of capillary pore, refining the microstructure of cement hydrates, and effectively using fiber reinforcement. The dense and fine microstructure of UHPC favor its potential to effectively disperse and interact with nanomaterials, which could complement the reinforcing action of fibers in UHPC. An optimization experimental program was implemented in order to identify the optimum combination of steel fiber and relatively low-cost carbon nanofiber in UHPC. The optimum volume fractions of steel fiber and carbon nanofiber identified for balanced improvement of flexural strength, ductility, energy sorption capacity, impact, and abrasion resistance of UHPC were 1.1% and 0.04%, respectively. Desired complementary/synergistic actions of nanofibers and steel fibers in UHPC were detected, which were attributed to their reinforcing effects at different scales, and the potential benefits of nanofibers to interfacial bonding and pull-out behavior of fibers in UHPC. Modification techniques which enhanced the hydrophilicity and bonding potential of nanofibers to cement hydrates benefited their reinforcement efficiency in UHPC.

  10. Maximizing Tensile Strain in Germanium Nanomembranes for Enhanced Optoelectronic Properties

    Science.gov (United States)

    Sanchez Perez, Jose Roberto

    Silicon, germanium, and their alloys, which provide the leading materials platform of microelectronics, are extremely inefficient light emitters because of their indirect fundamental energy band gap. This basic materials property has so far hindered the development of group-IV photonic-active devices, including light emitters and diode lasers, thereby significantly limiting our ability to integrate electronic and photonic functionalities at the chip level. Theoretical studies have predicted that tensile strain in Ge lowers the direct energy band gap relative to the indirect one, and that, with sufficient strain, Ge becomes direct-band gap, thus enabling facile interband light emission and the fabrication of Group IV lasers. It has, however, not been possible to impart sufficient strain to Ge to reach the direct-band gap goal, because bulk Ge fractures at much lower strains. Here it is shown that very thin sheets of Ge(001), called nanomembranes (NMs), can be used to overcome this materials limitation. Germanium nanomembranes (NMs) in the range of thicknesses from 20nm to 100nm were fabricated and then transferred and mounted to a flexible substrate [a polyimide (PI) sheet]. An apparatus was developed to stress the PI/NM combination and provide for in-situ Raman measurements of the strain as a function of applied stress. This arrangement allowed for the introduction of sufficient biaxial tensile strain (>1.7%) to transform Ge to a direct-band gap material, as determined by photoluminescence (PL) measurements and theory. Appropriate shifts in the emission spectrum and increases in PL intensities were observed. The advance in this work was nanomembrane fabrication technology; i.e., making thin enough Ge sheets to accept sufficiently high levels of strain without fracture. It was of interest to determine if the strain at which fracture ultimately does occur can be raised, by evaluating factors that initiate fracture. Attempts to assess the effect of free edges (enchant

  11. TRISO coated fuel particles with enhanced SiC properties

    International Nuclear Information System (INIS)

    Lopez-Honorato, E.; Tan, J.; Meadows, P.J.; Marsh, G.; Xiao, P.

    2009-01-01

    The silicon carbide (SiC) layer used for the formation of TRISO coated fuel particles is normally produced at 1500-1650 deg. C via fluidized bed chemical vapor deposition from methyltrichlorosilane in a hydrogen environment. In this work, we show the deposition of SiC coatings with uniform grain size throughout the coating thickness, as opposed to standard coatings which have larger grain sizes in the outer sections of the coating. Furthermore, the use of argon as the fluidizing gas and propylene as a carbon precursor, in addition to hydrogen and methyltrichlorosilane, allowed the deposition of stoichiometric SiC coatings with refined microstructure at 1400 and 1300 deg. C. The deposition of SiC at lower deposition temperatures was also advantageous since the reduced heat treatment was not detrimental to the properties of the inner pyrolytic carbon which generally occurs when SiC is deposited at 1500 deg. C. The use of a chemical vapor deposition coater with four spouts allowed the deposition of uniform and spherical coatings.

  12. Modifying zirconia solid electrolyte surface property to enhance oxide transport

    Energy Technology Data Exchange (ETDEWEB)

    Liaw, B.Y.; Song, S.Y. [Univ. of Hawaii, Honolulu, HI (United States)

    1996-12-31

    Bismuth-strontium-calcium-copper oxide (Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8}, BSCCO) is known for its high T{sub c} superconducting behavior and mixed conducting property. The applicability of similar high T{sub c} cuprates for intermediate-temperature solid oxide fuel cell (SOFC) application has been studied recently. We investigated the electrochemical behavior of several Ag{vert_bar}BSCCO{vert_bar}10 mol% yttria-stabilized zirconia (YSZ){vert_bar}Ag and Ag{vert_bar}YSZ{vert_bar}Ag cells using complex impedance spectroscopy. A highly uniform and porous microstructure was observed at the interface of the YSZ and BSCCO. The ionic conductivity determined from the Nyquest plots in the temperature range of 200-700{degrees}C agrees with the values reported in the literature. The specific resistance of the BSCCO{vert_bar}YSZ interface was also determined to be lower than those of the conventional manganite electrode, suggesting that BSCCO seems attractive for cathode applications in SOFC.

  13. Enhanced electrical properties in bilayered ferroelectric thin films

    Science.gov (United States)

    Zhang, Hao; Long, WeiJie; Chen, YaQing; Guo, DongJie

    2013-03-01

    Sr2Bi4Ti5O18 (SBTi) single layered and Sr2Bi4Ti5O18/Pb(Zr0.53Ti0.47)O3 (SBTi/PZT) bilayered thin films have been prepared on Pt/TiO2/SiO2/Si substrates by pulsed-laser deposition (PLD). The related structural characterizations and electrical properties have been comparatively investigated. X-ray diffraction reveals that both films have crystallized into perovskite phases and scanning electron microscopy shows the sharp interfaces. Both films show well-saturated ferroelectric hysteresis loops, however, compared with the single layered SBTi films, the SBTi/PZT bilayered films have significantly increased remnant polarization ( P r) and decreased coercive field ( E c), with the applied field of 260 kV/cm. The measured P r and E c of SBTi and SBTi/PZT films were 7.9 μC/cm2, 88.1 kV/cm and 13.0 μC/cm2, 51.2 kV/cm, respectively. In addition, both films showed good fatigue-free characteristics, the switchable polarization decreased by 9% and 11% of the initial values after 2.2×109 switching cycles for the SBTi single layered films and the SBTi/PZT bilayered films, respectively. Our results may provide some guidelines for further optimization of multilayered ferroelectric thin films.

  14. Ultra-nanocrystalline diamond nanowires with enhanced electrochemical properties

    International Nuclear Information System (INIS)

    Shalini, Jayakumar; Lin, Yi-Chieh; Chang, Ting-Hsun; Sankaran, Kamatchi Jothiramalingam; Chen, Huang-Chin; Lin, I.-Nan; Lee, Chi-Young; Tai, Nyan-Hwa

    2013-01-01

    The effects of N 2 incorporation in Ar/CH 4 plasma on the electrochemical properties and microstructure of ultra-nanocrystalline diamond (UNCD) films are reported. While the electrical conductivity of the films increased monotonously with increasing N 2 content (up to 25%) in the plasma, the electrochemical behavior was optimized for UNCD films grown in (Ar–10% N 2 )/CH 4 plasma. Transmission electron microscopy showed that the main factor resulting in high conductivity in the films was the formation of needle-like nanodiamond grains and the induction graphite layer encapsulating these grains. The electrochemical process for N 2 -incorporated UNCD films can readily be activated due to the presence of nanographite along the grain boundaries of the films. The formation of needle-like diamond grains was presumably due to the presence of CN species that adhered to the existing nanodiamond clusters, which suppressed radial growth of the nanodiamond crystals, promoting anisotropic growth and the formation of needle-like nanodiamond. The N 2 -incorporated UNCD films outperformed other electrochemical electrode materials, such as boron-doped diamond and glassy carbon, in that the UNCD electrodes could sense dopamine, urea, and ascorbic acid simultaneously in the same mixture with clear resolution

  15. Nanoconfinement: an effective way to enhance PVDF piezoelectric properties.

    Science.gov (United States)

    Cauda, Valentina; Stassi, Stefano; Bejtka, Katarzyna; Canavese, Giancarlo

    2013-07-10

    The dimensional confinement and oriented crystallization are both key factors in determining the piezoelectric properties of a polymeric nanostructured material. Here we prepare arrays of one-dimensional polymeric nanowires showing piezoelectric features by template-wetting two distinct polymers into anodic porous alumina (APA) membranes. In particular, poly(vinylidene fluoride), PVDF, and its copolymer poly(vinylidene fluoride-trifluoroethylene), PVTF, are obtained in commercially available APA, showing a final diameter of about 200 nm and several micrometers in length, reflecting the templating matrix features. We show that the crystallization of both polymers into a ferroelectric phase is directed by the nanotemplate confinement. Interestingly, the PVDF nanowires mainly crystallize into the β-phase in the nanoporous matrix, whereas the reference thin film of PVDF crystallizes in the α nonpolar phase. In the case of the PVTF nanowires, needle-like crystals oriented perpendicularly to the APA channel walls are observed, giving insight on the molecular orientation of the polymer within the nanowire structure. A remarkable piezoelectric behavior of both 1-D polymeric nanowires is observed, upon recording ferroelectric polarization, hysteresis, and displacement loops. In particular, an outstanding piezoelectric effect is observed for the PVDF nanowires with respect to the polymeric thin film, considering that no poling was carried out. Current versus voltage (I-V) characteristics showed a consistent switching behavior of the ferroelectric polar domains, thus revealing the importance of the confined and oriented crystallization of the polymer in monodimensional nanoarchitectures.

  16. Carbon Nanotube Chopped Fiber for Enhanced Properties in Additive Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Menchhofer, Paul A [ORNL; Lindahl, John M [ORNL; JohnsonPhD, DR Joseph E. [Nanocomp Technologies, Inc.

    2016-06-06

    Nanocomp Technologies, Inc. is working with Oak Ridge National Laboratory to develop carbon nanotube (CNT) composite materials and evaluate their use in additive manufacturing (3D printing). The first phase demonstrated feasibility and improvements for carbon nanotube (CNT)- acrylonitrile butadiene styrene (ABS) composite filaments use in additive manufacturing, with potential future work centering on further improvements. By focusing the initial phase on standard processing methods (developed mainly for the incorporation of carbon fibers in ABS) and characterization techniques, a basis of knowledge for the incorporation of CNTs in ABS was learned. The ability to understand the various processing variables is critical to the successful development of these composites. From the degradation effects on ABS (caused by excessive temperatures), to the length of time the ABS is in the melt state, to the order of addition of constituents, and also to the many possible mixing approaches, a workable flow sequence that addresses each processing step is critical to the final material properties. Although this initial phase could not deal with each of these variables in-depth, a future study is recommended that will build on the lessons learned for this effort.

  17. Differences in antiproliferative effect of STAT3 inhibition in HCC cells with versus without HBV expression

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Yun; Zhou, Lin; Xie, Haiyang; Wang, Weilin [Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, First Affiliated Hospital, School of Medicine, Zhejiang University, Qingchun Road 79, Hangzhou, Zhejiang 310003 (China); Key Laboratory of Combined Multi-organ Transplantation of Ministry of Public Health, Qingchun Road 79, Hangzhou, Zhejiang 310003 (China); Zheng, Shusen, E-mail: shusenzheng@zju.edu.cn [Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, First Affiliated Hospital, School of Medicine, Zhejiang University, Qingchun Road 79, Hangzhou, Zhejiang 310003 (China); Key Laboratory of Combined Multi-organ Transplantation of Ministry of Public Health, Qingchun Road 79, Hangzhou, Zhejiang 310003 (China)

    2015-06-05

    Chronic infection with hepatitis B virus (HBV) plays an important role in the etiology of hepatocellular carcinoma (HCC). Signal transducer and activator of transcription 3 (STAT3) inactivation could inhibit the tumor growth of HCC. In this study, differential antiproliferative effect of STAT3 inhibition was observed with HBV-related HCC cells being more resistant than non-HBV-related HCC cells. Resistance of HBV-related HCC cells to STAT3 inhibition was positively correlated to the expression of HBV. Enhanced ERK activation after STAT3 blockade was detected in HBV-related HCC cells but not in non-HBV-related HCC cells. Combined ERK and STAT3 inhibition eliminates the discrepancy between the two types of HCC cells. Moderate reduced HBV expression was found after STAT3 inhibition. These findings disclose a discrepancy in cellular response to STAT3 inhibition between non-HBV-related and HBV-related HCC cells and underscore the complexity of antiproliferative effect of STAT3 inactivation in HBV-related HCC cells. - Highlights: • HBV endows HCC cells with resistance to STAT3 inactivation on proliferation. • Abnormal ERK activation after STAT3 inhibition in HBV-related HCC cells. • Combined ERK and STAT3 inhibition eliminates the discrepancy. • STAT3 inhibition moderately reduces HBV expression.

  18. Differences in antiproliferative effect of STAT3 inhibition in HCC cells with versus without HBV expression

    International Nuclear Information System (INIS)

    Hong, Yun; Zhou, Lin; Xie, Haiyang; Wang, Weilin; Zheng, Shusen

    2015-01-01

    Chronic infection with hepatitis B virus (HBV) plays an important role in the etiology of hepatocellular carcinoma (HCC). Signal transducer and activator of transcription 3 (STAT3) inactivation could inhibit the tumor growth of HCC. In this study, differential antiproliferative effect of STAT3 inhibition was observed with HBV-related HCC cells being more resistant than non-HBV-related HCC cells. Resistance of HBV-related HCC cells to STAT3 inhibition was positively correlated to the expression of HBV. Enhanced ERK activation after STAT3 blockade was detected in HBV-related HCC cells but not in non-HBV-related HCC cells. Combined ERK and STAT3 inhibition eliminates the discrepancy between the two types of HCC cells. Moderate reduced HBV expression was found after STAT3 inhibition. These findings disclose a discrepancy in cellular response to STAT3 inhibition between non-HBV-related and HBV-related HCC cells and underscore the complexity of antiproliferative effect of STAT3 inactivation in HBV-related HCC cells. - Highlights: • HBV endows HCC cells with resistance to STAT3 inactivation on proliferation. • Abnormal ERK activation after STAT3 inhibition in HBV-related HCC cells. • Combined ERK and STAT3 inhibition eliminates the discrepancy. • STAT3 inhibition moderately reduces HBV expression

  19. Oldenlandia diffusa Promotes Antiproliferative and Apoptotic Effects in a Rat Hepatocellular Carcinoma with Liver Cirrhosis

    Directory of Open Access Journals (Sweden)

    Yun-Young Sunwoo

    2015-01-01

    Full Text Available Oldenlandia diffusa (OD is commonly used with various diseases such as cancer, arthritis, and autoimmune disease. Liver cirrhosis is a predominant risk factor for hepatocellular carcinoma (HCC. Here, we show that the therapeutic effect of OD, which was investigated both in vitro and chemically, induced HCC model. OD significantly enhanced apoptosis and antiproliferative activity and reduced migration ability of HCC cells. In vivo, OD was treated twice a day for 28 days after confirmed HCC model through 2-[18F]-fluoro-2-deoxy-D-glucose (18F-FDG imaging. The survival in OD treated groups was shown to have a greater therapeutic effect than the control group. 28 days after OD treatment, OD treated groups resulted in a significant reduction in tumor number, size, 18F-FDG uptake, and serum levels such as alanine transaminase, aspartate transaminase, and alkaline phosphate compared to the control group. Also, proliferated cells in tumor sites by OD were reduced compared to the control group. Furthermore, several rats in OD treated group survived over 60 days and liver morphology of these rats showed the difference between tumor mass and normal tissue. These results suggest that OD may have antiproliferative activity, inhibition of metastasis, and apoptotic effects in chemically induced HCC model and can have the potential use for clinical application as anticancer drug of the herbal extract.

  20. Chemical Potential Tuning and Enhancement of Thermoelectric Properties in Indium Selenides.

    Science.gov (United States)

    Rhyee, Jong-Soo; Kim, Jin Hee

    2015-03-20

    Researchers have long been searching for the materials to enhance thermoelectric performance in terms of nano scale approach in order to realize phonon-glass-electron-crystal and quantum confinement effects. Peierls distortion can be a pathway to enhance thermoelectric figure-of-merit ZT by employing natural nano-wire-like electronic and thermal transport. The phonon-softening known as Kohn anomaly, and Peierls lattice distortion decrease phonon energy and increase phonon scattering, respectively, and, as a result, they lower thermal conductivity. The quasi-one-dimensional electrical transport from anisotropic band structure ensures high Seebeck coefficient in Indium Selenide. The routes for high ZT materials development of In₄Se₃ - δ are discussed from quasi-one-dimensional property and electronic band structure calculation to materials synthesis, crystal growth, and their thermoelectric properties investigations. The thermoelectric properties of In₄Se₃ - δ can be enhanced by electron doping, as suggested from the Boltzmann transport calculation. Regarding the enhancement of chemical potential, the chlorine doped In₄Se₃ - δ Cl 0.03 compound exhibits high ZT over a wide temperature range and shows state-of-the-art thermoelectric performance of ZT = 1.53 at 450 °C as an n -type material. It was proven that multiple elements doping can enhance chemical potential further. Here, we discuss the recent progress on the enhancement of thermoelectric properties in Indium Selenides by increasing chemical potential.

  1. Chemical Potential Tuning and Enhancement of Thermoelectric Properties in Indium Selenides

    Directory of Open Access Journals (Sweden)

    Jong-Soo Rhyee

    2015-03-01

    Full Text Available Researchers have long been searching for the materials to enhance thermoelectric performance in terms of nano scale approach in order to realize phonon-glass-electron-crystal and quantum confinement effects. Peierls distortion can be a pathway to enhance thermoelectric figure-of-merit ZT by employing natural nano-wire-like electronic and thermal transport. The phonon-softening known as Kohn anomaly, and Peierls lattice distortion decrease phonon energy and increase phonon scattering, respectively, and, as a result, they lower thermal conductivity. The quasi-one-dimensional electrical transport from anisotropic band structure ensures high Seebeck coefficient in Indium Selenide. The routes for high ZT materials development of In4Se3−δ are discussed from quasi-one-dimensional property and electronic band structure calculation to materials synthesis, crystal growth, and their thermoelectric properties investigations. The thermoelectric properties of In4Se3−δ can be enhanced by electron doping, as suggested from the Boltzmann transport calculation. Regarding the enhancement of chemical potential, the chlorine doped In4Se3−δCl0.03 compound exhibits high ZT over a wide temperature range and shows state-of-the-art thermoelectric performance of ZT = 1.53 at 450 °C as an n-type material. It was proven that multiple elements doping can enhance chemical potential further. Here, we discuss the recent progress on the enhancement of thermoelectric properties in Indium Selenides by increasing chemical potential.

  2. Schinus terebinthifolius: phenolic constituents and in vitro antioxidant, antiproliferative and in vivo anti-inflammatory activities

    Directory of Open Access Journals (Sweden)

    Marciane M. da Silva

    Full Text Available ABSTRACT Schinus terebinthifolius Raddi, Anacardiaceae, native to Brazil, is referred to as "pimento-rosa" and is used to treat inflammatory disease in folk medicine. Studies have reported important pharmacological properties, but these effects have still not been fully exploited. This study reports that the crude extract and isolated compounds of S. terebinthifolius (leaves have in vitro antioxidant, antiproliferative, and in vivo anti-inflammatory activities. The samples were evaluated for antioxidant activity using 2, 2-diphenyl-1-picrylhydrazyl, β-carotene/linoleic acid and 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid reagents. The anti-inflammatory effects were assayed against a carrageenan-induced paw oedema model in mice to test doses of 10, 100 and 300 mg/kg at different time points in addition to myeloperoxidase activity analysis. The antiproliferative activity was evaluated using ten human tumour cell lines. Two derivatives of gallic acid and four flavonoids were isolated and exhibited considerable antioxidant activity. The extract and its compounds showed selectivity towards ovarian cancer cells, with growth inhibitory activity values ranging from 1.9 to 6.5 µg/ml. Sample extracts and methyl gallate significantly inhibited carrageenan-induced oedema in the mice paw oedema experimental model. The calculated topological polar surface area for methyl gallate (86.98 Å2 showed good intestinal absorption. The effects reported herein are be related to the presence of flavonoids and the galloyl phenolic derivative content.

  3. Apoptotic and anti-proliferative effects of all-trans retinoic acid

    International Nuclear Information System (INIS)

    Zamora, Monica; Ortega, Juan Alberto; Alana, Lide; Vinas, Octavi; Mampel, Teresa

    2006-01-01

    We examined the apoptotic and anti-proliferative effects of all-trans retinoic acid (atRA) in HeLa cells. Our results demonstrated that HeLa cells were more sensitive to the anti-proliferative effects of atRA than to its apoptotic effects. Furthermore, we demonstrated that caspase inhibition attenuates cell death but does not alter the atRA-dependent reduction in cell proliferation, which suggests that atRA-induced apoptosis is independent of the arrest in cell proliferation. To check whether ANT proteins mediated these atRA effects, we transiently transfected cells with expression vectors encoding for individual ANT (adenine nucleotide translocase 1-3). Our results revealed that ANT1 and ANT3 over-expressing HeLa cells increased their atRA sensitivity. Thus, our results not only demonstrate the different functional activities of ANT isoforms, but also contribute to a better understanding of the properties of atRA as an anti-tumoral agent used in cancer therapy

  4. Anti-inflammatory, antiproliferative, and cytoprotective activity of NO chimera nitrates of use in cancer chemoprevention.

    Science.gov (United States)

    Hagos, Ghenet K; Abdul-Hay, Samer O; Sohn, Johann; Edirisinghe, Praneeth D; Chandrasena, R Esala P; Wang, Zhiqiang; Li, Qian; Thatcher, Gregory R J

    2008-11-01

    Nonsteroidal anti-inflammatory drugs (NSAIDs) have shown promise in colorectal cancer (CRC), but they are compromised by gastrotoxicity. NO-NSAIDs are hybrid nitrates conjugated to an NSAID designed to exploit the gastroprotective properties of NO bioactivity. The NO chimera ethyl 2-((2,3-bis(nitrooxy)propyl)disulfanyl)benzoate (GT-094), a novel nitrate containing an NSAID and disulfide pharmacophores, is effective in vivo in rat models of CRC and is a lead compound for design of agents of use in CRC. Preferred chemopreventive agents possess 1) antiproliferative and 2) anti-inflammatory actions and 3) the ability to induce cytoprotective phase 2 enzymes. To determine the contribution of each pharmacophore to the biological activity of GT-094, these three biological activities were studied in vitro in compounds that deconstructed the structural elements of the lead GT-094. The anti-inflammatory and antiproliferative actions of GT-094 in vivo were recapitulated in vitro, and GT-094 was seen to induce phase 2 enzymes via the antioxidant responsive element. In the variety of colon, macrophage-like, and liver cell lines studied, the evidence from structure-activity relationships was that the disulfide structural element of GT-094 is the dominant contributor in vitro to the anti-inflammatory activity, antiproliferation, and enzyme induction. The results provide a direction for lead compound refinement. The evidence for a contribution from the NO mimetic activity of nitrates in vitro was equivocal, and combinations of nitrates with acetylsalicylic acid were inactive.

  5. Antiproliferative effects of an analog of curcumin in Hep-2 cells: a comparative study with curcumin.

    Science.gov (United States)

    Kumaravel, Mohankumar; Sankar, Pajaniradje; Latha, Periyasamy; Benson, Chellakan S; Rukkumani, Rajagopalan

    2013-02-01

    Curcumin, the major active principle of Curcuma longa, is one of the promising, plant-derived, chemopreventive agents being studied for its anticarcinogenic and antioxidant properties. Hence, in our study, we aimed at testing the antiproliferative efficacy of an o-hydroxyl substituted analog of curcumin, bis demethoxy curcumin analog (BDMC-A), and comparing its efficacy with that of curcumin. BDMC-A was synthesised with a yield of 78% and 98% purity. Hep-2 cells and the MTT cell viability assay were used to examine cell proliferation. LDH assay and cell counts were performed to assess the cytotoxicity and anti-proliferative effects of the compound, respectively. Flow cytometry followed by Western blot were performed to investigate the cell cycle distribution. BDMC-A inhibited cell proliferation at a much lower concentration (IC50 20 microM) than curcumin (IC50 50 microM). Similar effects were observed in the LDH release and cell count assays. Flow cytometric studies using propidium iodide showed accumulation of cells in the G0/G1 phase and the arrest was further confirmed by immunoblotting of protein cyclin D1. BDMC-A was more potent in inhibiting the cells at a lower dose when compared with curcumin. Our results showed that the analog of curcumin is likely to possess more efficacy compared with curcumin in inhibiting cancer.

  6. Antiproliferative and Apoptosis Induction Potential of the Methanolic Leaf Extract of Holarrhena floribunda (G. Don

    Directory of Open Access Journals (Sweden)

    J. A. Badmus

    2015-01-01

    Full Text Available Natural plant products with potent growth inhibition and apoptosis induction properties are extensively being investigated for their cancer chemopreventive potential. Holarrhena floribunda (HF is used in a wide range of traditional medicine practices. The present study investigated the antiproliferative and apoptosis induction potential of methanolic leaf extracts of HF against breast (MCF-7, colorectal (HT-29, and cervical (HeLa cancer cells relative to normal KMST-6 fibroblasts. The MTT assay in conjunction with the trypan blue dye exclusion and clonogenic assays were used to determine the effects of the extracts on the cells. Caspase activities were assayed with Caspase-Glo 3/7 and Caspase-9 kits. Apoptosis induction was monitored by flow cytometry using the APOPercentage and Annexin V-FITC kits. Reactive oxygen species (ROS was measured using the fluorogenic molecular probe 5-(and-6-chloromethyl-2′,7′-dichlorofluorescein diacetate acetyl ester and cell cycle arrest was detected with propidium iodide. Dose-response analyses of the extract showed greater sensitivity in cancer cell lines than in fibroblast controls. Induction of apoptosis, ROS, and cell cycle arrest were time- and dose-dependent for the cancer cell lines studied. These findings provide a basis for further studies on the isolation, characterization, and mechanistic evaluation of the bioactive compounds responsible for the antiproliferative activity of the plant extract.

  7. Antioxidant and Antiproliferative Activities of Heated Sterilized Pepsin Hydrolysate Derived from Half-Fin Anchovy (Setipinna taty

    Directory of Open Access Journals (Sweden)

    Dongfeng Wang

    2011-06-01

    Full Text Available In this paper we studied the antioxidant and antiproliferative activities of the heated pepsin hydrolysate from a marine fish half-fin anchovy (HAHp-H. Furthermore, we compared the chemical profiles including the amino acid composition, the browning intensity, the IR and UV-visible spectra, and the molecular weight distribution between the half-fin anchovy pepsin hydrolysate (HAHp and HAHp-H. Results showed that heat sterilization on HAHp improved the 1,1-diphenyl-2-picryl-hydrazil (DPPH radical-scavenging activity and reducing power. In addition, the antiproliferative activities were all increased for HAHp-H on DU-145 human prostate cancer cell line, 1299 human lung cancer cell line and 109 human esophagus cancer cell line. The contents of free amino acid and reducing sugar of HAHp-H were decreased (P < 0.05. However, hydrophobic amino acid residues and the browning intensity of HAHp-H were increased. FT-IR spectroscopy indicated that amide I and amide III bands of HAHp-H were slightly modified, whereas band intensity of amide II was reduced dramatically. Thermal sterilization resulted in the increased fractions of HAHp-H with molecular weight of 3000–5000 Da and below 500 Da. The enhanced antioxidant and antiproliferative activities of HAHp-H might be attributed to the Maillard reaction.

  8. Antiproliferative and Pro-Apoptotic Effect of Novel Nitro-Substituted Hydroxynaphthanilides on Human Cancer Cell Lines

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    Tereza Kauerova

    2016-07-01

    Full Text Available Ring-substituted hydroxynaphthanilides are considered as cyclic analogues of salicylanilides, compounds possessing a wide range of pharmacological activities, including promising anticancer properties. The aim of this study was to evaluate the potential anticancer effect of novel nitro-substituted hydroxynaphthanilides with a special focus on structure-activity relationships. The antiproliferative effect was assessed by Water Soluble Tetrazolium Salts-1 (WST-1 assay, and cytotoxicity was evaluated via dye exclusion test. Flow cytometry was used for cell cycle analysis and detection of apoptosis using Annexin V-FITC/PI assay. Protein expression was estimated by Western blotting. Our data indicate that the potential to cause the antiproliferative effect increases with the shift of the nitro substituent from the ortho- to the para-position. The most potent compounds, 3-hydroxy-N-(3-nitrophenylnaphthalene-2-carboxamide (2, and 2-hydroxy-N-(4-nitrophenyl-naphthalene-1-carboxamide (6 showed antiproliferative activity against THP-1 and MCF-7 cancer cells without affecting the proliferation of 3T3-L1 non-tumour cells. Compounds 2 and 6 induced the accumulation of THP-1 and MCF-7 cells in G1 phase associated with the downregulation of cyclin E1 protein levels, while the levels of cyclin B1 were not affected. Moreover, compound 2 was found to exert the pro-apoptotic effect on the THP-1 cells. These results suggest that hydroxynaphthanilides might represent a potential model structure for the development of novel anticancer agents.

  9. NO-Releasing Enmein-Type Diterpenoid Derivatives with Selective Antiproliferative Activity and Effects on Apoptosis-Related Proteins

    Directory of Open Access Journals (Sweden)

    Dahong Li

    2016-09-01

    Full Text Available A series of nine enmein-type ent-kaurane diterpenoid and furoxan-based nitric oxide (NO donor hybrids (10a–i were designed and synthesized from commercially available oridonin (1. These hybrids were evaluated for their antiproliferative activity against Bel-7402, K562, MGC-803, and CaEs-17 human cancer cell lines and L-02 normal liver cells. The antiproliferative activity against tumor cells was stronger than the lead compound 1 and parent molecule 9 in most cases. Especially, compound 10f showed the strongest activity against human hepatocarcinoma Bel-7402 cell line with an IC50 of 0.81 μM and could also release 33.7 μmol/L NO at the time point of 60 min. Compounds 10a–i also showed cytotoxic selectivity between tumor and normal liver cells with IC50 ranging from 22.1 to 33.9 μM. Furthermore, the apoptotic properties on Bel-7402 cells revealed that 10f could induce S phase cell cycle arrest and apoptosis at low micromolar concentrations. The effects of 10f on apoptosis-related proteins were also investigated. The potent antiproliferative activities and mechanistic studies warrant further preclinical investigations.

  10. Fullerene–epoxy nanocomposites-enhanced mechanical properties at low nanofiller loading

    International Nuclear Information System (INIS)

    Rafiee, Mohammad A.; Yavari, Fazel; Rafiee, Javad; Koratkar, Nikhil

    2011-01-01

    In this study, we characterized the mechanical properties of fullerence (C 60 ) epoxy nanocomposites at various weight fractions of fullerene additives in the epoxy matrix. The mechanical properties measured were the Young’s modulus, ultimate tensile strength, fracture toughness, fracture energy, and the material’s resistance to fatigue crack propagation. All of the above properties of the epoxy polymer were significantly enhanced by the fullerene additives at relatively low nanofiller loading fractions (∼0.1 to 1% of the epoxy matrix weight). By contrast, other forms of nanoparticle fillers such as silica, alumina, and titania nanoparticles require up to an order of magnitude higher weight fraction to achieve comparable enhancement in properties.

  11. Composition, antimicrobial, antioxidant, and antiproliferative activity of Origanum dictamnus (dittany essential oil

    Directory of Open Access Journals (Sweden)

    Gregoria Mitropoulou

    2015-05-01

    Full Text Available Background: Nowadays, there has been an increased interest in essential oils from various plant origins as potential antimicrobial, antioxidant, and antiproliferative agents. This trend can be mainly attributed to the rising number and severity of food poisoning outbreaks worldwide along with the recent negative consumer perception against artificial food additives and the demand for novel functional foods with possible health benefits. Origanum dictamnus (dittany is an aromatic, tender perennial plant that only grows wild on the mountainsides and gorges of the island of Crete in Greece. Objective: The aim of the present study was to investigate the antimicrobial, antioxidant, and antiproliferative properties of O. dictamnus essential oil and its main components and assess its commercial potential in the food industry. Design: O. dictamnus essential oil was initially analyzed by gas chromatography–mass spectrometry (GC–MS to determine semi-quantitative chemical composition of the essential oils. Subsequently, the antimicrobial properties were assayed and the minimum inhibitory and non-inhibitory concentration values were determined. The antioxidant activity and cytotoxic action against the hepatoma adenocarcinoma cell line HepG2 of the essential oil and its main components were further evaluated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH assay and by the sulforhodamine B (SRB assay, respectively. Results: The main constituents of O. dictamnus essential oil identified by GC–MS analysis were carvacrol (52.2%, γ-terpinene (8.4%, p-cymene (6.1%, linalool (1.4%, and caryophyllene (1.3%. O. dictamnus essential oil and its main components were effective against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Listeria monocytogenes, Salmonella Enteritidis, Salmonella typhimurium, Saccharomyces cerevisiae, and Aspergillus niger. In addition, the estimated IC50 value for the DPPH radical scavenging activity for O. dictamnus

  12. Composition, antimicrobial, antioxidant, and antiproliferative activity of Origanum dictamnus (dittany) essential oil.

    Science.gov (United States)

    Mitropoulou, Gregoria; Fitsiou, Eleni; Stavropoulou, Elisavet; Papavassilopoulou, Eleni; Vamvakias, Manolis; Pappa, Aglaia; Oreopoulou, Antigoni; Kourkoutas, Yiannis

    2015-01-01

    Nowadays, there has been an increased interest in essential oils from various plant origins as potential antimicrobial, antioxidant, and antiproliferative agents. This trend can be mainly attributed to the rising number and severity of food poisoning outbreaks worldwide along with the recent negative consumer perception against artificial food additives and the demand for novel functional foods with possible health benefits. Origanum dictamnus (dittany) is an aromatic, tender perennial plant that only grows wild on the mountainsides and gorges of the island of Crete in Greece. The aim of the present study was to investigate the antimicrobial, antioxidant, and antiproliferative properties of O. dictamnus essential oil and its main components and assess its commercial potential in the food industry. O. dictamnus essential oil was initially analyzed by gas chromatography-mass spectrometry (GC-MS) to determine semi-quantitative chemical composition of the essential oils. Subsequently, the antimicrobial properties were assayed and the minimum inhibitory and non-inhibitory concentration values were determined. The antioxidant activity and cytotoxic action against the hepatoma adenocarcinoma cell line HepG2 of the essential oil and its main components were further evaluated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and by the sulforhodamine B (SRB) assay, respectively. The main constituents of O. dictamnus essential oil identified by GC-MS analysis were carvacrol (52.2%), γ-terpinene (8.4%), p-cymene (6.1%), linalool (1.4%), and caryophyllene (1.3%). O. dictamnus essential oil and its main components were effective against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Listeria monocytogenes, Salmonella Enteritidis, Salmonella typhimurium, Saccharomyces cerevisiae, and Aspergillus niger. In addition, the estimated IC50 value for the DPPH radical scavenging activity for O. dictamnus essential oil was 0.045±0.0042% (v/v) and was mainly

  13. Characterization and Antiproliferative Activity of Nobiletin-Loaded Chitosan Nanoparticles

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    Ana G. Luque-Alcaraz

    2012-01-01

    Full Text Available Nobiletin is a polymethoxyflavonoid with a remarkable antiproliferative effect. In order to overcome its low aqueous solubility and chemical instability, the use of nanoparticles as carriers has been proposed. This study explores the possibility of binding nobiletin to chitosan nanoparticles, as well as to evaluate their antiproliferative activity. The association and loading efficiencies are 69.1% and 7.0%, respectively. The formation of an imine bond between chitosan amine groups and the carbonyl group of nobiletin, via Schiff-base, is proposed. Nobiletin-loaded chitosan nanoparticles exhibit considerable inhibition (IC50=8 μg/mL of cancerous cells, revealing their great potential for applications in cancer chemotherapy.

  14. Rosmarinus officinalis essential oil: antiproliferative, antioxidant and antibacterial activities

    Directory of Open Access Journals (Sweden)

    Abdullah Ijaz Hussain

    2010-12-01

    Full Text Available The aim of this work was to investigate and compare the antiproliferative, antioxidant and antibacterial activities of Rosmarinus officinalis essential oil, native to Pakistan. The essential oil content from the leaves of R. officinalis was 0.93 g 100g-1. The GC and GC-MS analysis revealed that the major components determined in R. officinalis essential oil were 1,8-cineol (38.5%, camphor (17.1%, α-pinene (12.3%, limonene (6.23%, camphene (6.00% and linalool (5.70%. The antiproliferative activity was tested against two cancer (MCF-7 and LNCaP and one fibroblast cell line (NIH-3T3 using the MTT assay, while, the antioxidant activity was evaluated by the reduction of 2, 2-diphenyl-1-picryl hydrazyl (DPPH and measuring percent inhibition of peroxidation in linoleic acid system. The disc diffusion and modified resazurin microtitre-plate assays were used to evaluate the inhibition zones (IZ and minimum inhibitory concentration (MIC of R. officinalis essential oil, respectively. It is concluded from the results that Rosmarinus officinalis essential oil exhibited antiproliferative, antioxidant and antibacterial activities.

  15. Antioxidant and antiproliferative activity of Granny Smith apple pomace

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    Savatović Slađana M.

    2008-01-01

    Full Text Available Granny Smith apple pomace was subjected to evaluation as valuable source of antioxidant and anticancer phytochemicals on the basis of its content in phenolic compounds, antioxidant and antiproliferative activity. The total cotent of phenolics, flavonoids and flavan-3-ols in apple pomace determined spectrophotometrically, was 7.02 mg/g, 0.51 mg/g and 8.80 mg/g. Major phenolics (phenolic acids, flavan-3-ols, flavonoids and dihydrochalcons in apple pomace were identified and quantified by HPLC. The antioxidant activity of apple pomace on stable 1,1-diphenyl-2-picrylhydrazyl (DPPH and reactive hydroxyl radicals, was investigated by electron spin resonance (ESR spectroscopy. The IC50 DPPH and IC50 OH values of Granny Smith apple pomace were 9.51 mg/ml and 29.17 mg/ml, respectively. The antiproliferative activities of apple pomace on cervix epitheloid carcinoma (HeLa, colon adenocarcinoma (HT-29 and breast adenocarcinoma (MCF7 cell lines were determined according to the MTT (3-(4,5-dimethylthiazol-2-yl- 2,5-diphenyltetrazolium bromide colorimetric assay. The IC50 HeLa , IC50 HT-29 and IC50 MCF7 values of Granny Smith apple pomace were 26.40 mg/ml, 22.47 mg/ml and 21.26 mg/ml, respectively. The significant correlations between antioxidant activities and antiproliferative activities were established (p<0.05.

  16. SnO2 nanosheets grown on graphene sheets with enhanced lithium storage properties.

    Science.gov (United States)

    Ding, Shujiang; Luan, Deyan; Boey, Freddy Yin Chiang; Chen, Jun Song; Lou, Xiong Wen David

    2011-07-07

    We demonstrate a new hydrothermal method to directly grow SnO(2) nanosheets on a graphene oxide support that is subsequently reduced to graphene. This unique SnO(2)/graphene hybrid structure exhibits enhanced lithium storage properties with high reversible capacities and good cycling performance. This journal is © The Royal Society of Chemistry 2011

  17. A theranostic agent to enhance osteogenic and magnetic resonance imaging properties of calcium phosphate cements

    NARCIS (Netherlands)

    Ventura, M.; Sun, Y.; Cremers, S.; Borm, P.; Tahmasebi Birgani, Zeinab; Habibovic, Pamela; Heerschap, A.; van der Kraan, P.M.; Jansen, J.A.; Walboomers, X.F.

    2014-01-01

    With biomimetic biomaterials, like calcium phosphate cements (CPCs), non-invasive assessment of tissue regeneration is challenging. This study describes a theranostic agent (TA) to simultaneously enhance both imaging and osteogenic properties of such a bone substitute material. For this purpose,

  18. Anisotropic Effective Mass, Optical Property, and Enhanced Band Gap in BN/Phosphorene/BN Heterostructures.

    Science.gov (United States)

    Hu, Tao; Hong, Jisang

    2015-10-28

    Phosphorene is receiving great research interests because of its peculiar physical properties. Nonetheless, the phosphorus has a trouble of degradation due to oxidation. Hereby, we propose that the electrical and optical anisotropic properties can be preserved by encapsulating into hexagonal boron nitride (h-BN). We found that the h-BN contributed to enhancing the band gap of the phosphorene layer. Comparing the band gap of the pristine phosphorene layer, the band gap of the phosphorene/BN(1ML) system was enhanced by 0.15 eV. It was further enhanced by 0.31 eV in the BN(1ML)/phosphorene/BN(1ML) trilayer structure. However, the band gap was not further enhanced when we increased the thickness of the h-BN layers even up to 4 MLs. Interestingly, the anisotropic effective mass and optical property were still preserved in BN/phosphorene/BN heterostructures. Overall, we predict that the capping of phosphorene by the h-BN layers can be an excellent solution to protect the intrinsic properties of the phosphorene.

  19. Gallic Acid Content and an Antioxidant Mechanism Are Responsible for the Antiproliferative Activity of ‘Ataulfo’ Mango Peel on LS180 Cells

    Directory of Open Access Journals (Sweden)

    Gustavo. R. Velderrain-Rodríguez

    2018-03-01

    Full Text Available Mango “Ataulfo” peel is a rich source of polyphenols (PP, with antioxidant and anti-cancer properties; however, it is unknown whether such antiproliferative activity is related to PP’s antioxidant activity. The content (HPLC-DAD, antioxidant (DPPH, FRAP, ORAC, and antiproliferative activities (MTT of free (FP and chemically-released PP from mango ‘Ataulfo’ peel after alkaline (AKP and acid (AP hydrolysis, were evaluated. AKP fraction was higher (µg/g DW in gallic acid (GA; 23,816 ± 284 than AP (5610 ± 8 of FR (not detected fractions. AKP fraction and GA showed the highest antioxidant activity (DPPH/FRAP/ORAC and GA’s antioxidant activity follows a single electron transfer (SET mechanism. AKP and GA also showed the best antiproliferative activity against human colon adenocarcinoma cells (LS180; IC50 (µg/mL 138.2 ± 2.5 and 45.7 ± 5.2 and mouse connective cells (L929; 93.5 ± 7.7 and 65.3 ± 1.2; Cheminformatics confirmed the hydrophilic nature (LogP, 0.6 and a good absorption capacity (75% for GA. Data suggests that GA’s antiproliferative activity appears to be related to its antioxidant mechanism, although other mechanisms after its absorption could also be involved.

  20. Antiproliferative and Molecular Mechanism of Eugenol-Induced Apoptosis in Cancer Cells

    Directory of Open Access Journals (Sweden)

    Eko Supriyanto

    2012-05-01

    Full Text Available Phenolic phytochemicals are a broad class of nutraceuticals found in plants which have been extensively researched by scientists for their health-promoting potential. One such a compound which has been comprehensively used is eugenol (4-allyl-2-methoxyphenol, which is the active component of Syzigium aromaticum (cloves. Aromatic plants like nutmeg, basil, cinnamon and bay leaves also contain eugenol. Eugenol has a wide range of applications like perfumeries, flavorings, essential oils and in medicine as a local antiseptic and anesthetic. Increasing volumes of literature showed eugenol possesses antioxidant, antimutagenic, antigenotoxic, anti-inflammatory and anticancer properties. Molecular mechanism of eugenol-induced apoptosis in melanoma, skin tumors, osteosarcoma, leukemia, gastric and mast cells has been well documented. This review article will highlight the antiproliferative activity and molecular mechanism of the eugenol induced apoptosis against the cancer cells and animal models.

  1. Heme oxygenase is not involved in the anti-proliferative effects of statins on pancreatic cancer cells

    International Nuclear Information System (INIS)

    Vanova, K.; Boukalova, S.; Gbelcova, H.; Muchova, L.; Neuzil, J.; Gurlich, R.; Ruml, T.; Vitek, L.

    2016-01-01

    Pancreatic cancer is recognized as one of the most fatal tumors due to its aggressiveness and resistance to therapy. Statins were previously shown to inhibit the proliferation of cancer cells via various signaling pathways. In healthy tissues, statins activate the heme oxygenase pathway, nevertheless the role of heme oxygenase in pancreatic cancer is still controversial. The aim of this study was to evaluate, whether anti-proliferative effects of statins in pancreatic cancer cells are mediated via the heme oxygenase pathway. In vitro effects of various statins and hemin, a heme oxygenase inducer, on cell proliferation were evaluated in PA-TU-8902, MiaPaCa-2 and BxPC-3 human pancreatic cancer cell lines. The effect of statins on heme oxygenase activity was assessed and heme oxygenase-silenced cells were used for pancreatic cancer cell proliferation studies. Cell death rate and reactive oxygen species production were measured in PA-TU-8902 cells, followed by evaluation of the effect of cerivastatin on GFP-K-Ras trafficking and expression of markers of invasiveness, osteopontin (SPP1) and SOX2. While simvastatin and cerivastatin displayed major anti-proliferative properties in all cell lines tested, pravastatin did not affect the cell growth at all. Strong anti-proliferative effect was observed also for hemin. Co-treatment of cerivastatin and hemin increased anti-proliferative potential of these agents, via increased production of reactive oxygen species and cell death compared to individual treatment. Heme oxygenase silencing did not prevent pancreatic cancer cells from the tumor-suppressive effect of cerivastatin or hemin. Cerivastatin, but not pravastatin, protected Ras protein from trafficking to the cell membrane and significantly reduced expressions of SPP1 (p < 0.05) and SOX2 (p < 0.01). Anti-proliferative effects of statins and hemin on human pancreatic cancer cell lines do not seem to be related to the heme oxygenase pathway. While hemin triggers reactive

  2. Enhancement in thermal property and mechanical property of phase change microcapsule with modified carbon nanotube

    International Nuclear Information System (INIS)

    Li, Min; Chen, Meirong; Wu, Zhishen

    2014-01-01

    Highlights: • Carbon nanotubes was grafted and used to enhance the thermal conductivities of the microcapsules. • The average particle size of the prepared MicroPCMs/CNTs-SA is 0.1 μm. • The thermal conductivity of MicroPCMs/CNTs-SA with 4% of CNTs increased by 79.2% compared with MicroPCMs. • MicroPCMs/CNTs-SA has better durability and thermal stability compared to the original MicroPCMs. - Abstract: Carbon nanotubes grafted with stearyl alcohol (CNTs-SA) was used in synthesizing phase change microcapsules (MicroPCMs) in order to enhance the thermal conductivities of the microcapsules. Urea–formaldehyde resin (UFR) was used as wall material. Scanning Electron Microscope (SEM), laser particle size analyzer, Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimeter (DSC) are employed to characterize the prepared MicroPCMs containing the grafted CNTs (MicroPCMs/CNTs-SA). The results indicated that CNTs improved the performance of microcapsules. The average particle diameter of MicroPCMs/CNTs-SA is much smaller than that of MicroPCMs. There was no chemical reaction among paraffin, CNTs and UFR. The phase change temperature and latent heat of MicroPCMs/CNTs-SA was 26.2 °C and 47.7 J/g, respectively. The thermal conductivity of MicroPCMs/CNTs-SA with 4% of CNTs increased by 79.2% compared with MicroPCMs. The initial decomposition temperature of MicroPCMs/CNTs-SA is 38 °C higher than that of MicroPCMs. After 100 heating and cooling cycles, MicroPCMs/CNTs-SA still has good durability and thermal stability

  3. Laser induced surface structuring of Cu for enhancement of field emission properties

    Science.gov (United States)

    Akram, Mahreen; Bashir, Shazia; Jalil, Sohail Abdul; Shahid Rafique, Muhammad; Hayat, Asma; Mahmood, Khaliq

    2018-02-01

    The effect of Nd:YAG (1064 nm, 10 ns, 10 Hz) laser induced surface structuring of copper (Cu) for enhancement of field emission (FE) properties has been investigated. X-ray diffraction analysis was employed to investigate the surface structural and compositional modifications. The surface structuring was explored by scanning electron microscope investigation. FE properties were studied under UHV conditions in a parallel plate configuration of planar un-irradiated Cu anode and laser irradiated Cu cathode. The Fowler-Nordheim plots were drawn to confirm the dominance of FE behavior of the measured I-V characteristics. The obtained values of turn-on field ‘E o’, field enhancement factor ‘β’ and maximum current density ‘J max’ come out to be to be in the range of 5.5-8.5 V μm-1, 1380-2730 and 147-375 μA cm-2 respectively for the Cu samples irradiated at laser irradiance ranging from 13 to 50 GW cm-2. The observed enhancement in the FE properties has been correlated with the growth of various surface structures such as ridged protrusions, cones and pores/tiny holes. The porous morphology is found to be responsible for a significant enhancement in the FE parameters.

  4. Enhancement in transport properties of seeded melt-textured YBCO by Cu-site doping

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yu X. [Department of Physics, Hong Kong Baptist University, Kowloon (China); Texas Center for Superconductivity and Department of Mechanical Engineering, University of Houston, Houston, TX (United States); Lo, W.; Salama, Kamel [Texas Center for Superconductivity and Department of Mechanical Engineering, University of Houston, Houston, TX (United States); Tang, Tong B. [Department of Physics, Hong Kong Baptist University, Kowloon (China)

    2002-05-01

    A significant research effort has been made worldwide to introduce nanometre-scale weak superconducting regions into seeded melt-textured superconductors to enhance their critical current density, trapped magnetic field and levitation force. The enhancement in these properties is dependent on the pinning forces exerted on the magnetic flux lines. In this paper we present a substantial improvement in the transport properties of these materials by optimizing the fabrication conditions, controlling the oxygen deficiency, as well as adjusting the doping level of Zn in YBa{sub 2}(Cu{sub 1-x}Zn{sub x}){sub 3}O{sub 7-}{delta} large grains. The enhancement is found to be as much as 30% by doping between about x=0.001 25 and 0.002 53. The results strongly indicate that the introduction of local nanometre-scale weak superconducting regions by Zn substitution for Cu in the CuO{sub 2} plane enhances the transport properties. Due to the simplicity of the processing conditions, these doping techniques can have a significant potential for a variety of engineering applications. (author)

  5. Potent anti-proliferative effects against oral and cervical cancers of Thai medicinal plants selected from the Thai/Lanna medicinal plant recipe database "MANOSROI III".

    Science.gov (United States)

    Manosroi, Aranya; Akazawa, Hiroyuki; Pattamapun, Kassara; Kitdamrongtham, Worapong; Akihisa, Toshihiro; Manosroi, Worapaka; Manosroi, Jiradej

    2015-07-01

    Thai/Lanna medicinal plant recipes have been used for the treatment of several diseases including oral and cervical cancers. To investigate anti-proliferative activity on human cervical (HeLa) and oral (KB) cancer cell lines of medicinal plants selected from Thai/Lanna medicinal plant recipe database "MANOSROI III". Twenty-three methanolic plant crude extracts were tested for phytochemicals and anti-proliferative activity on HeLa and KB cell lines for 24 h by the sulforhodamine B (SRB) assay at the doses of 1 × 10(1)-1 × 10(-6 )mg/ml. The nine extracts with the concentrations giving 50% growth inhibition (GI50) lower than 100 µg/ml were further semi-purified by liquid/liquid partition in order to evaluate and enhance the anti-proliferative potency. All extracts contained steroids/triterpenoids, but not xanthones. The methanolic extracts of Gloriosa superba L. (Colchinaceae) root and Albizia chinensis (Osbeck) Merr. (Leguminosae-Mimosoideae) wood gave the highest anti-proliferative activity on HeLa and KB cell lines with the GI50 values of 0.91 (6.0- and 0.31-fold of cisplatin and doxorubicin) and 0.16 µg/ml (28.78- and 82.29-fold of cisplatin and doxorubicin), respectively. Hexane and methanol-water fractions of G. superba exhibited the highest anti-proliferative activity on HeLa and KB cell lines with the GI50 values of 0.15 (37- and 1.9-fold of cisplatin and doxorubicin) and 0.058 µg/ml (77.45- and 221.46-fold of cisplatin and doxorubicin), respectively. This study has demonstrated the potential of plants selected from MANOSROI III database especially G. superba and A. chinensis for further development as anti-oral and cervical cancer agents.

  6. Enhanced field emission properties of carbon nanotube bundles confined in SiO2 pits

    Science.gov (United States)

    Lim, Yu Dian; Grapov, Dmitry; Hu, Liangxing; Kong, Qinyu; Tay, Beng Kang; Labunov, Vladimir; Miao, Jianmin; Coquet, Philippe; Aditya, Sheel

    2018-02-01

    It has been widely reported that carbon nanotubes (CNTs) exhibit superior field emission (FE) properties due to their high aspect ratios and unique structural properties. Among the various types of CNTs, random growth CNTs exhibit promising FE properties due to their reduced inter-tube screening effect. However, growing random growth CNTs on individual catalyst islands often results in spread out CNT bundles, which reduces overall field enhancement. In this study, significant improvement in FE properties in CNT bundles is demonstrated by confining them in microfabricated SiO2 pits. Growing CNT bundles in narrow (0.5 μm diameter and 2 μm height) SiO2 pits achieves FE current density of 1-1.4 A cm-2, which is much higher than for freestanding CNT bundles (76.9 mA cm-2). From the Fowler Nordheim plots, confined CNT bundles show a higher field enhancement factor. This improvement can be attributed to the reduced bundle diameter by SiO2 pit confinement, which yields bundles with higher aspect ratios. Combining the obtained outcomes, it can be conclusively summarized that confining CNTs in SiO2 pits yields higher FE current density due to the higher field enhancement of confined CNTs.

  7. Enhancing and quenching luminescence with gold nanoparticle films: the influence of substrate on the luminescent properties

    International Nuclear Information System (INIS)

    Guidelli, Eder José; Baffa, Oswaldo; Ramos, Ana Paula

    2016-01-01

    Gold nanoparticle (AuNP) films were sputtered over glass and aluminum substrates to enhance optically stimulated luminescence (OSL), a luminescent technique employed for radiation detection, from x-ray irradiated NaCl nanocrystals. The AuNP films deposited over glass led to enhanced-OSL emission, whereas the AuNP films deposited on aluminum substrates quenched the OSL emission. The enhanced-OSL intensity is proportional to the optical density of the film's plasmon resonance band at the stimulation wavelength. For the case of the AuNP/aluminum films, the luminescence quenching diminishes, and OSL intensity partially recovers upon increasing the distance between the AuNPs and the aluminum substrates, and between the luminescent nanocrystals and the AuNP films. These results suggest that plasmonic interactions between the emitter nanocrystals, the localized surface plasmons (LSP) of the AuNPs, and the substrate are responsible for the OSL enhancement and quenching. In this sense, the substrate dictates whether LSP relaxation occurs by radiative or non-radiative transisitions, leading to enhanced or quenched OSL, respectively. Therefore, besides showing that AuNP films can enhance and/or tune the sensitivity of luminescent radiation detectors, and demonstrating OSL as a new technique to investigate mechanisms of plasmon-enhanced luminescence, these results bring insights on how substrates strongly modify the optical properties of AuNP films. (paper)

  8. Enhancing the biophysical properties of mRFP1 through incorporation of fluoroproline

    Energy Technology Data Exchange (ETDEWEB)

    Deepankumar, Kanagavel; Nadarajan, Saravanan Prabhu; Ayyadurai, Niraikulam; Yun, Hyungdon, E-mail: hyungdon@ynu.ac.kr

    2013-11-01

    Graphical abstract: Enhancing the biophysical properties of mRFP1 through incorporation of (2S, 4R)-4-fluoroproline at proline residues after mutating non-permissive site Pro63 into Ala. -- Highlights: •We incorporate (4S)-FP into mRFP1 led to insoluble protein. •Whereas, incorporation of (4R)-FP resulted in soluble but lost its fluorescence. •mRFP1-P63A mutant accommodate (4R)-FP and gave soluble protein with fluorescence. •Moreover mRFP1-P63A[(4R)-FP] showed enhanced biophysical properties of protein. -- Abstract: Here we enhanced the stability and biophysical properties of mRFP1 through a combination of canonical and non-canonical amino acid mutagenesis. The global replacement of proline residue with (2S, 4R)-4-fluoroproline [(4R)-FP] into mRFP1 led to soluble protein but lost its fluorescence, whereas (2S, 4S)-4-fluoroproline [(4S)-FP] incorporation resulted in insoluble protein. The bioinformatics analysis revealed that (4R)-FP incorporation at Pro63 caused fluorescence loss due to the steric hindrance of fluorine atom of (4R)-FP with the chromophore. Therefore, Pro63 residue was mutated with the smallest amino acid Ala to maintain non coplanar conformation of the chromophore and helps to retain its fluorescence with (4R)-FP incorporation. The incorporation of (4R)-FP into mRFP1-P63A showed about 2–3-fold enhancement in thermal and chemical stability. The rate of maturation is also greatly accelerated over the presence of (4R)-FP into mRFP1-P63A. Our study showed that a successful enhancement in the biophysical property of mRFP1-P63A[(4R)-FP] using non-canonical amino acid mutagenesis after mutating non-permissive site Pro63 into Ala.

  9. Enhancing the biophysical properties of mRFP1 through incorporation of fluoroproline

    International Nuclear Information System (INIS)

    Deepankumar, Kanagavel; Nadarajan, Saravanan Prabhu; Ayyadurai, Niraikulam; Yun, Hyungdon

    2013-01-01

    Graphical abstract: Enhancing the biophysical properties of mRFP1 through incorporation of (2S, 4R)-4-fluoroproline at proline residues after mutating non-permissive site Pro63 into Ala. -- Highlights: •We incorporate (4S)-FP into mRFP1 led to insoluble protein. •Whereas, incorporation of (4R)-FP resulted in soluble but lost its fluorescence. •mRFP1-P63A mutant accommodate (4R)-FP and gave soluble protein with fluorescence. •Moreover mRFP1-P63A[(4R)-FP] showed enhanced biophysical properties of protein. -- Abstract: Here we enhanced the stability and biophysical properties of mRFP1 through a combination of canonical and non-canonical amino acid mutagenesis. The global replacement of proline residue with (2S, 4R)-4-fluoroproline [(4R)-FP] into mRFP1 led to soluble protein but lost its fluorescence, whereas (2S, 4S)-4-fluoroproline [(4S)-FP] incorporation resulted in insoluble protein. The bioinformatics analysis revealed that (4R)-FP incorporation at Pro63 caused fluorescence loss due to the steric hindrance of fluorine atom of (4R)-FP with the chromophore. Therefore, Pro63 residue was mutated with the smallest amino acid Ala to maintain non coplanar conformation of the chromophore and helps to retain its fluorescence with (4R)-FP incorporation. The incorporation of (4R)-FP into mRFP1-P63A showed about 2–3-fold enhancement in thermal and chemical stability. The rate of maturation is also greatly accelerated over the presence of (4R)-FP into mRFP1-P63A. Our study showed that a successful enhancement in the biophysical property of mRFP1-P63A[(4R)-FP] using non-canonical amino acid mutagenesis after mutating non-permissive site Pro63 into Ala

  10. Enhanced catalytic properties of mesoporous mordenite for benzylation of benzene with benzyl alcohol

    Energy Technology Data Exchange (ETDEWEB)

    Saxena, Sandeep K.; Viswanadham, Nagabhatla, E-mail: nagabhatla.viswanadham@gmail.com

    2017-01-15

    Graphical abstract: The nano size pores (∼10 nm) created in the microporous mordenite zeolite facilitated enhanced catalytic activity to produce as high as 97 wt.% yield of di-phenyl methane in the benzylation of benzene with benzyl alcohol at solvent-free liquid phase reaction conditions. - Highlights: • Nano pores of ∼10 nm size have been created in microporous mordenite. • Dealumination at optimized conditions resulted in enhanced properties of mordenite. • Hierarchically porous mordenite enhanced bulky catalytic reactions. • As high as 97% selectivity to Di-phenyl methane obtained. • Solvent-free, liquid phase alkylation catalyst with stable activity for reusability. - Abstract: Zeolite mordenite has been treated with nitric acid at different severities so as to facilitate the framework dealumination and optimization of the textural properties such as acidity and porosity. The samples obtained have been characterized by X-ray diffraction, FTIR, SEM, TEM, surface area, porosity by N{sub 2} adsorption and ammonia TPD. The resultant samples have been evaluated towards the bulky alkylation reaction of benzylation of benzene with benzyl alcohol. The studies indicated the improvement in the textural properties such as surface area, pore volume and acidity of the samples after the acid treatment. While, the phenomenon of enhancement in properties was exhibited by all the acid treated mordenite samples, the highest improvement in properties was observed at a particular condition of acid treatment (SM-2 sample). This particular sample also exhibited highest acidity and the presence of ∼10 nm size pores that resulted in the effective catalytic activity towards the bulky alkylation reaction of benzene with benzyl alcohol to produce high yields of di-phenyl methane.

  11. Modification of curcumin with polyethylene glycol enhances the delivery of curcumin in preadipocytes and its antiadipogenic property.

    Science.gov (United States)

    Kim, Choon Young; Bordenave, Nicolas; Ferruzzi, Mario G; Safavy, Ahmad; Kim, Kee-Hong

    2011-02-09

    Conjugation of curcumin (CCM) by polyethylene glycol (PEG) has been previously developed to improve water solubility of the natural form of CCM and its antiproliferative role in some human cancer cell lines. This study examined the cellular uptake kinetics of the natural form of CCM and CCM-PEG. Their cytotoxic effect in proliferating preadipocytes and antiadipogenic property in differentiating preadipocytes had also been investigated. CCM and CCM-PEG were found to be differently absorbed in 3T3-L1 preadipocytes and adipocytes with a limited amount of CCM-PEG absorption in the cell. The improved water solubility of CCM-PEG was correlated with increased cellular retention of CCM in 3T3-L1 cells, particularly in preadipocytes. Consequently, CCM-PEG treatment sensitized proliferating preadipocytes to CCM-induced cell toxicity. Furthermore, incubation of differentiating 3T3-L1 cells with CCM-PEG resulted in improvement of the inhibitory role of CCM in adipocyte differentiation with no toxic effect. These results suggest that pegylation-improved water solubility and cellular retention of CCM may be uniquely useful for improving the delivery of CCM in preadipocytes and its antiadipogenic ability.

  12. 8-O-Azeloyl-14-benzoylaconine: a new alkaloid from the roots of Aconitum karacolicum Rapcs and its antiproliferative activities.

    Science.gov (United States)

    Chodoeva, Ainura; Bosc, Jean-Jacques; Guillon, Jean; Decendit, Alain; Petraud, Michel; Absalon, Christelle; Vitry, Christiane; Jarry, Christian; Robert, Jacques

    2005-12-01

    A new alkaloid of Aconitum karacolicum Rapcs, from the Ranunculaceae family, collected in Kirghizstan, was isolated from the roots of this plant, using a purification scheme based upon its in vitro antiproliferative properties against three human tumour cell lines in culture. Structural identification was performed using high resolution MS-MS mass spectrometry and (1)H, (13)C, 2D NOESY NMR spectroscopy analysis. This compound consists of a 14-benzoylaconine moiety substituted on C-8 by an azeloyl chain. It presents in vitro cytotoxicity with an IC(50) of about 10-20 microM, which warrants further investigation on its possible interest in cancer chemotherapy.

  13. Plasmon mediated enhancement and tuning of optical emission properties of two dimensional graphitic carbon nitride nanosheets.

    Science.gov (United States)

    Bayan, Sayan; Gogurla, Narendar; Midya, Anupam; Singha, Achintya; Ray, Samit K

    2017-12-01

    We demonstrate surface plasmon induced enhancement and tunablilty in optical emission properties of two dimensional graphitic carbon nitride (g-C 3 N 4 ) nanosheets through the attachment of gold (Au) nanoparticles. Raman spectroscopy has revealed surface enhanced Raman scattering that arises due to the combined effect of the charge transfer process and localized surface plasmon induced enhancement in electromagnetic field, both occurring at the nanoparticle-nanosheet interface. Photoluminescence studies suggest that at an optimal concentration of nanoparticles, the emission intensity can be enhanced, which is maximum within the 500-525 nm region. Further, the fabricated electroluminescent devices reveal that the emission feature can be tuned from bluish-green to red (∼160 nm shift) upon attaching Au nanoparticles. We propose that the π*→π transition in g-C 3 N 4 can trigger surface plasmon oscillation in Au, which subsequently increases the excitation process in the nanosheets and results in enhanced emission in the green region of the photoluminescence spectrum. On the other hand, electroluminescence of g-C 3 N 4 can induce plasmon oscillation more efficiently and thus can lead to red emission from Au nanoparticles through the radiative damping of particle plasmons. The influence of nanoparticle size and coverage on the emission properties of two dimensional g-C 3 N 4 , nanosheets has also been studied in detail.

  14. Enhanced magnetodielectric and multiferroic properties of Er-doped bismuth ferrite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, A.; Banerjee, M. [Department of Physics, National Institute of Technology, Durgapur 713209 (India); Basu, S., E-mail: soumen.basu@phy.nitdgp.ac.in [Department of Physics, National Institute of Technology, Durgapur 713209 (India); Mukadam, M.D.; Yusuf, S.M. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Pal, M. [CSIR-Central Glass & Ceramic Research Institute, Kolkata 700032 (India)

    2015-07-15

    An enhancement in multiferroic properties has been achieved for chemically prepared BFO nanoparticles by doping with erbium (Er). XRD along with electron microscopy study reveals the phase purity and nanocrystalline nature of BFO. Enhancement of both the magnetic moment and resistivity is observed by virtue of Er doping. The observed enhanced magnetic moment is considered to be associated with smaller crystallite whereas increase of resistivity may be attributed to a decrease of oxygen vacancies. Doping also display an improvement of leakage behaviour and dielectric constant in nanocrystalline BFO, reflected in well-developed P-E loop. In addition, large enhancement in magnetodielectric coefficient is observed because of Er doping. Therefore, the results provide interesting approaches to improve the multiferroic properties of BFO, which has great implication towards its applications. - Highlights: • Synthesis of pure Er-doped BFO nanoparticles by chemical route. • Large increase in magnetic moment and resistivity due to Er doping. • Er doping produce well developed P-E loop and enhance polarization. • Drastic increase in dielectric constant as well as magnetodielectric coefficient observes because of Er doping.

  15. Enhancement of heat transfer coefficient multi-metallic nanofluid with ANFIS modeling for thermophysical properties

    Directory of Open Access Journals (Sweden)

    Balla Hyder H.

    2015-01-01

    Full Text Available Cu and Zn-water nanofluid is a suspension of the Cu and Zn nanoparticles with the size 50 nm in the water base fluid for different volume fractions to enhance its Thermophysical properties. The determination and measuring the enhancement of Thermophysical properties depends on many limitations. Nanoparticles were suspended in a base fluid to prepare a nanofluid. A coated transient hot wire apparatus was calibrated after the building of the all systems. The vibro-viscometer was used to measure the dynamic viscosity. The measured dynamic viscosity and thermal conductivity with all parameters affected on the measurements such as base fluids thermal conductivity, volume factions, and the temperatures of the base fluid were used as input to the Artificial Neural Fuzzy inference system to modeling both dynamic viscosity and thermal conductivity of the nanofluids. Then, the ANFIS modeling equations were used to calculate the enhancement in heat transfer coefficient using CFD software. The heat transfer coefficient was determined for flowing flow in a circular pipe at constant heat flux. It was found that the thermal conductivity of the nanofluid was highly affected by the volume fraction of nanoparticles. A comparison of the thermal conductivity ratio for different volume fractions was undertaken. The heat transfer coefficient of nanofluid was found to be higher than its base fluid. Comparisons of convective heat transfer coefficients for Cu and Zn nanofluids with the other correlation for the nanofluids heat transfer enhancement are presented. Moreover, the flow demonstrates anomalous enhancement in heat transfer nanofluids.

  16. Enhanced Mechanical Properties of Poplar Wood by a Combined-Hydro-Thermo-Mechanical (CHTM) Modification

    OpenAIRE

    Houri Sharifnia; Behbood Mohebbi

    2011-01-01

    The current research explains an innovated technique to enhanced mechanice properties of poplar wood by combination of two modification techniques, hydrothermal and mechanical. Blocks of 50×55×500mm3 were cut from poplar wood and treated in a reactor at 120, 150 and 180°C for 30 min. Afterwards, the blocks were pressed at 180°C for 20 min at a pressure of 80 bar to achieve a compression set of 60% in radial direction. Density and bending properties (moduli of elasticity and rupture) as well a...

  17. Non-toxic poly(ethylene terephthalate)/clay nanocomposites with enhanced barrier properties

    KAUST Repository

    Hayrapetyan, Suren

    2012-01-01

    Motivated by the technological need for poly(ethylene terephthalate) materials with improved barrier properties together with the requirement for sustainability this study focuses on an eco-friendly sulfonated polyester as clay compatibilizer to facilitate polymer mixing during melt compounding. We demonstrate that the nanocomposites based on sulfonated polyester are a reliable alternative to their imidazolium counterparts, exhibiting enhanced properties (water vapor and UV transmission), without sacrificing the excellent transparency, clarity and mechanical strength of the matrix. © 2011 Elsevier Ltd. All rights reserved.

  18. Enhanced dispersion of carbon nanotubes in hyperbranched polyurethane and properties of nanocomposites

    International Nuclear Information System (INIS)

    Rana, Sravendra; Karak, Niranjan; Cho, Jae Whan; Kim, Young Ho

    2008-01-01

    Hyperbranched polyurethane (HBPU) nanocomposites with multi-walled carbon nanotubes (MWNTs) were prepared by in situ polymerization on the basis of poly(ε-caprolactone)diol as the soft segment, 4,4'-methylene bis(phenylisocyanate) as the hard segment, and castor oil as the multifunctional group for the hyperbranched structure. A dominant improvement in the dispersion of MWNTs in the HBPU matrix was found, and good solubility of HBPU-MWNT nanocomposites in organic solvents was shown. Due to the well-dispersed MWNTs, the nanocomposites resulted in achieving excellent shape memory properties as well as enhanced mechanical properties compared to pure HBPU.

  19. Antiproliferative Activity of Phenylpropanoids Isolated from Lagotis brevituba Maxim.

    Science.gov (United States)

    Xiang, Yuan; Jing, Zhao; Haixia, Wang; Ruitao, Yu; Huaixiu, Wen; Zenggen, Liu; Lijuan, Mei; Yiping, Wang; Yanduo, Tao

    2017-10-01

    The aim of the present study was to evaluate the antiproliferative effect of phenylpropanoids isolated from the n-BuOH-soluble fraction of an ethanolic extract of Lagotis brevituba Maxim. The phenylpropanoids were identified as echinacoside, lagotioside, glucopyranosyl(1-6)martynoside, plantamoside, and verbascoside. Three of the compounds, lagotioside, glucopyranosyl(1-6)martynoside, and plantamoside, were isolated from L. brevituba for the first time. The antiproliferative activity of the isolates was evaluated in human gastric carcinoma (MGC-803), human colorectal carcinoma (HCT116), human hepatocellar carcinoma (HepG2), and human lung cancer (HCT116) cells using an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Plantamoside showed promising activity against MGC-803 cells, with a half maximal inhibitory concentration value of 37.09 μM. The mechanism of the pro-apoptosis effect of plantamoside was then evaluated in MGC-803 cells. Changes in cell morphology, including disorganization of the architecture of actin microfilaments and formation of apoptotic bodies, together with cell cycle arrest in G2/M phases, were observed after treatment of plantamoside. The antiproliferative and pro-apoptotic effects were associated with a decrease in the ratio of Bcl-2/Bax and reduced mitochondrial membrane potential, which was accompanied by the release of reactive oxygen species and Ca 2+ into the cytoplasm. Taken together, the results indicated that plantamoside promotes apoptosis via a mitochondria-dependent mechanism. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  20. ITO films with enhanced electrical properties deposited on unheated ZnO-coated polymer substrates

    International Nuclear Information System (INIS)

    Nunes de Carvalho, C.; Lavareda, G.; Fortunato, E.; Alves, H.; Goncalves, A.; Varela, J.; Nascimento, R.; Amaral, A.

    2005-01-01

    Indium tin oxide (ITO) films were deposited by radio frequency (rf)-plasma enhanced reactive thermal evaporation (rf-PERTE) at room temperature on intrinsic ZnO/polymer substrates to enhance their electrical and structural properties. The polymer substrate used is polyethylene terephthalate (PET). The thickness of the ZnO films varied in the range 50-150 nm. The average thickness of the ITO films is of about 170 nm. Results show that ITO deposited on bare PET substrates exhibit: an average visible transmittance of about 85% and an electrical resistivity of 5.6 x 10 -2 Ω cm. ITO on ZnO/PET substrates show the optical quality practically preserved and the resistivity decreased to a minimum value of 1.9x10 -3 Ω cm for ZnO layers 125 nm thick. The electrical properties of ITO on ZnO/PET are largely improved by the increase in carrier mobility

  1. Enhanced performance in capacitive force sensors using carbon nanotube/polydimethylsiloxane nanocomposites with high dielectric properties

    Science.gov (United States)

    Jang, Hyeyoung; Yoon, Hyungsuk; Ko, Youngpyo; Choi, Jaeyoo; Lee, Sang-Soo; Jeon, Insu; Kim, Jong-Ho; Kim, Heesuk

    2016-03-01

    Force sensors have attracted tremendous attention owing to their applications in various fields such as touch screens, robots, smart scales, and wearable devices. The force sensors reported so far have been mainly focused on high sensitivity based on delicate microstructured materials, resulting in low reproducibility and high fabrication cost that are limitations for wide applications. As an alternative, we demonstrate a novel capacitive-type force sensor with enhanced performance owing to the increased dielectric properties of elastomers and simple sensor structure. We rationally design dielectric elastomers based on alkylamine modified-multi-walled carbon nanotube (MWCNT)/polydimethylsiloxane (PDMS) composites, which have a higher dielectric constant than pure PDMS. The alkylamine-MWCNTs show excellent dispersion in a PDMS matrix, thus leading to enhanced and reliable dielectric properties of the composites. A force sensor array fabricated with alkylamine-MWCNT/PDMS composites presents an enhanced response due to the higher dielectric constant of the composites than that of pure PDMS. This study is the first to report enhanced performance of capacitive force sensors by modulating the dielectric properties of elastomers. We believe that the disclosed strategy to improve the sensor performance by increasing the dielectric properties of elastomers has great potential in the development of capacitive force sensor arrays that respond to various input forces.Force sensors have attracted tremendous attention owing to their applications in various fields such as touch screens, robots, smart scales, and wearable devices. The force sensors reported so far have been mainly focused on high sensitivity based on delicate microstructured materials, resulting in low reproducibility and high fabrication cost that are limitations for wide applications. As an alternative, we demonstrate a novel capacitive-type force sensor with enhanced performance owing to the increased

  2. Magnetorheological technology for fabricating tunable solid electrolyte with enhanced conductivity and mechanical property

    Science.gov (United States)

    Peng, Gangrou; Ge, Yu; Ding, Jie; Wang, Caiyun; Wallace, Gordon G.; Li, Weihua

    2018-03-01

    Ionogels are a new class of hybrid materials where ionic liquids are immobilized by macromolecular support. The excessive amount of crosslinking polymer enhances the mechanical strength but compromises the conductivity. Here, we report an elastomeric magnetorheological (MR) ionogel with an enhanced conductivity and mechanical strength as well. Following the application of magnetic nanoparticles into an ionic liquid containing minimum cross-linking agent, the formation, thus physical properties, of MR ionogels are co-controlled by simultaneously applied UV light and external magnetic field. The application of MR ionogels as solid electrolytes in supercapacitors is also demonstrated to study electrochemical performance. This work opens a new avenue to synthesize robust ionogels with the desired conductivity and controllable mechanical properties for soft flexible electronic devices. Besides, as a new class of conductive MR elastomers, the proposed MR ionogel also possesses the potential for engineering applications, such as sensors and actuators.

  3. Enhancement of optical properties of InAs quantum dots grown by using periodic arsine interruption

    International Nuclear Information System (INIS)

    Kim, Jungsub; Yang, Changjae; Sim, Uk; Lee, Jaeyel; Yoon, Euijoon; Lee, Youngsoo

    2009-01-01

    We investigated the morphological and optical properties of InAs quantum dots (QDs) grown by using periodic arsine interruption (PAI) and compared them with QDs grown conventionally. In the conventional growth, the formation of large islands was observed, which suppresses the nucleation and growth of QDs. Furthermore, the growth of capping layers was significantly degraded by these large islands. On the other hand, in the PAI growth, the formation of large islands was completely suppressed, resulting in the increase of the density and aspect ratio of QDs and the uniform growth of capping layers. As a result of photoluminescence (PL) measurements, we found that the emission efficiency was enhanced and the full-width-half-maximum was reduced to 32 meV. The temperature dependence of these optical properties also revealed the enhancement of the uniformity of QDs grown by the PAI method.

  4. Antiproliferative Activity and Cellular Uptake of Evodiamine and Rutaecarpine Based on 3D Tumor Models

    Directory of Open Access Journals (Sweden)

    Hui Guo

    2016-07-01

    Full Text Available Evodiamine (EVO and rutaecarpine (RUT are promising anti-tumor drug candidates. The evaluation of the anti-proliferative activity and cellular uptake of EVO and RUT in 3D multicellular spheroids of cancer cells would better recapitulate the native situation and thus better reflect an in vivo response to the treatment. Herein, we employed the 3D culture of MCF-7 and SMMC-7721 cells based on hanging drop method and evaluated the anti-proliferative activity and cellular uptake of EVO and RUT in 3D multicellular spheroids, and compared the results with those obtained from 2D monolayers. The drugs’ IC50 values were significantly increased from the range of 6.4–44.1 μM in 2D monolayers to 21.8–138.0 μM in 3D multicellular spheroids, which may be due to enhanced mass barrier and reduced drug penetration in 3D models. The fluorescence of EVO and RUT was measured via fluorescence spectroscopy and the cellular uptake of both drugs was characterized in 2D tumor models. The results showed that the cellular uptake concentrations of RUT increased with increasing drug concentrations. However, the EVO concentrations uptaken by the cells showed only a small change with increasing drug concentrations, which may be due to the different solubility of EVO and Rut in solvents. Overall, this study provided a new vision of the anti-tumor activity of EVO and RUT via 3D multicellular spheroids and cellular uptake through the fluorescence of compounds.

  5. Chemopreventive and Antiproliferative Effect of Andrographis Paniculata Extract

    Directory of Open Access Journals (Sweden)

    Agrawal RC

    2017-06-01

    Full Text Available An Andrographis paniculata leaf and stem extract was studied in Hela cells lines by In Vitro methods and anti promoting effect by skin tumour model. The dose dependent cytotoxicity was observed in HeLa cell lines by stem and leaves extracts of Andrographis paniculata extract. The prevention of bone marrow micronucleus formation by Andrographis paniculata leaves and stem extract was also observed. The reductions in tumour numbers were observed. The glutathione level was increased in the liver of animals which received the treatment of Andrographis extract along with DMBA + Croton Oil. The revealing information about the anticancer, antiproliferative and antimutagenic effect of an Andrographis paniculata extract was observed.

  6. Relationship between structure and antiproliferative activity of 1-azaflavanones.

    Science.gov (United States)

    Kawaii, Satoru; Endo, Kotaro; Tokiwano, Tetsuo; Yoshizawa, Yuko

    2012-07-01

    The synthesis of 19 derivatives of 2-phenyl-3,4-dihydroquinolin-4(1H)-one, as aza analogs of flavanones, was carried out and these compounds were further screened for their antiproliferative activity toward HL60 promyelocytic leukemia cells. In comparison with flavanone the replacement of C-ring ether oxygen atom with a nitrogen atom potentiated activity by more than 100-fold. It was suggested that the aromaticity of the B-ring contributes greatly to the activity of 1-azaflavanones.

  7. Enhancement of mechanical and electrical properties of continuous-fiber-reinforced epoxy composites with stacked graphene

    OpenAIRE

    Naveh, Naum; Shepelev, Olga; Kenig, Samuel

    2017-01-01

    Impregnation of expandable graphite (EG) after thermal treatment with an epoxy resin containing surface-active agents (SAAs) enhanced the intercalation of epoxy monomer between EG layers and led to further exfoliation of the graphite, resulting in stacks of few graphene layers, so-called “stacked” graphene (SG). This process enabled electrical conductivity of cured epoxy/SG composites at lower percolation thresholds, and improved thermo-mechanical properties were measured with either Kevlar, ...

  8. Tip-Enhanced Raman Scattering Microscopy: A Step toward Nanoscale Control of Intrinsic Molecular Properties

    Science.gov (United States)

    Yano, Taka-aki; Hara, Masahiko

    2018-06-01

    Tip-enhanced Raman scattering microscopy, a family of scanning probe microscopy techniques, has been recognized as a powerful surface analytical technique with both single-molecule sensitivity and angstrom-scale spatial resolution. This review covers the current status of tip-enhanced Raman scattering microscopy in surface and material nanosciences, including a brief history, the basic principles, and applications for the nanoscale characterization of a variety of nanomaterials. The focus is on the recent trend of combining tip-enhanced Raman scattering microscopy with various external stimuli such as pressure, voltage, light, and temperature, which enables the local control of the molecular properties and functions and also enables chemical reactions to be induced on a nanometer scale.

  9. In vitro anti-proliferative activity of clove extract on human gastric carcinoma

    Directory of Open Access Journals (Sweden)

    A. Karimi

    2017-10-01

    Full Text Available Background and objectives: Cancer cell resistance to common chemotherapy agents is on rise. Plants are considered valuable sources of herbal drugs for cancer therapy. The present study was conducted to investigate the in vitro antioxidant, anti-proliferative, and apoptosis-inducing properties of clove (Syzygium aromaticum L. extract in human gastric carcinoma (AGS. Methods: Crude ethanol extract of S. aromaticum dried buds was prepared and  in vitro anti-proliferative effects of the extract on AGS and normal Human dermal fibroblasts (HDF cell lines were studied by MTT assay. To examine apoptosis induction, AGS cells were incubated with IC50 concentrations of the extract, stained with propidium iodide (PI and annexin V-fluorescein isothiocyanate (FITC, and analyzed by flow cytometry. Antioxidant activity and total phenolics and flavonoids contents were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH assay, Folin-Ciocalteu method, and aluminum chloride colorimetric method, respectively. Results: The IC50 of DPPH and total phenolics and flavonoids contents of the extract were 10.05±1.93 μg/mL, 225.6±40 mg GAE/g, and 29.30±2.35 mgRUT/g, respectively. The IC50 of the extract against HDFs was 649 µg/mL, higher than AGS cells, which was 118.7 g/mL at 48 h after treatment. Flow cytometric analysis showed that the extract induced cell apoptosis. Conclusions: Crude ethanol S. aromaticum extract had high total phenolics content, and suppressed the proliferation of human gastric cancer cells, likely due to apoptosis induction. Further studies should be conducted to determine the mechanisms of its anticancer effects.

  10. Controlled biomineralization of electrospun poly(ε-caprolactone) fibers to enhance their mechanical properties.

    Science.gov (United States)

    Xie, Jingwei; Zhong, Shaoping; Ma, Bing; Shuler, Franklin D; Lim, Chwee Teck

    2013-03-01

    Electrospun polymeric fibers have been investigated as scaffolding materials for bone tissue engineering. However, their mechanical properties, and in particular stiffness and ultimate tensile strength, cannot match those of natural bones. The objective of the study was to develop novel composite nanofiber scaffolds by attaching minerals to polymeric fibers using an adhesive material - the mussel-inspired protein polydopamine - as a "superglue". Herein, we report for the first time the use of dopamine to regulate mineralization of electrospun poly(ε-caprolactone) (PCL) fibers to enhance their mechanical properties. We examined the mineralization of the PCL fibers by adjusting the concentration of HCO(3)(-) and dopamine in the mineralized solution, the reaction time and the surface composition of the fibers. We also examined mineralization on the surface of polydopamine-coated PCL fibers. We demonstrated the control of morphology, grain size and thickness of minerals deposited on the surface of electrospun fibers. The obtained mineral coatings render electrospun fibers with much higher stiffness, ultimate tensile strength and toughness, which could be closer to the mechanical properties of natural bone. Such great enhancement of mechanical properties for electrospun fibers through mussel protein-mediated mineralization has not been seen previously. This study could also be extended to the fabrication of other composite materials to better bridge the interfaces between organic and inorganic phases. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  11. Enhanced mechanical properties of epoxy nanocomposites by mixing noncovalently functionalized boron nitride nanoflakes.

    Science.gov (United States)

    Lee, Dongju; Song, Sung Ho; Hwang, Jaewon; Jin, Sung Hwan; Park, Kwang Hyun; Kim, Bo Hyun; Hong, Soon Hyung; Jeon, Seokwoo

    2013-08-12

    The influence of surface modifications on the mechanical properties of epoxy-hexagonal boron nitride nanoflake (BNNF) nanocomposites is investigated. Homogeneous distributions of boron nitride nanoflakes in a polymer matrix, preserving intrinsic material properties of boron nitride nanoflakes, is the key to successful composite applications. Here, a method is suggested to obtain noncovalently functionalized BNNFs with 1-pyrenebutyric acid (PBA) molecules and to synthesize epoxy-BNNF nanocomposites with enhanced mechanical properties. The incorporation of noncovalently functionalized BNNFs into epoxy resin yields an elastic modulus of 3.34 GPa, and 71.9 MPa ultimate tensile strength at 0.3 wt%. The toughening enhancement is as high as 107% compared to the value of neat epoxy. The creep strain and the creep compliance of the noncovalently functionalized BNNF nanocomposite is significantly less than the neat epoxy and the nonfunctionalized BNNF nanocomposite. Noncovalent functionalization of BNNFs is effective to increase mechanical properties by strong affinity between the fillers and the matrix. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Enhancement in microstructural and optoelectrical properties of thermally evaporated CdTe films for solar cells

    Science.gov (United States)

    Chander, Subhash; Dhaka, M. S.

    2018-03-01

    The optimization of microstructural and optoelectrical properties of a thin layer is an important step prior device fabrication process, so an enhancement in these properties of thermally evaporated CdTe thin films is reported in this communication. The films having thickness 450 nm and 850 nm were deposited on thoroughly cleaned glass and indium tin oxide (ITO) substrates followed by annealing at 450 °C in air atmosphere. These films were characterized for microstructural and optoelectrical properties employing X-ray diffraction, scanning electron microscopy coupled with energy-dispersive spectroscopy, UV-Vis spectrophotometer and source meter. The films found to be have zinc-blende cubic structure with preferred reflection (111) while the crystallographic parameters and direct energy band gap are strongly influenced by the film thickness. The surface morphology studies show that the films are uniform, smooth, homogeneous and nearly dense-packed as well as free from voids and pitfalls as where elemental analysis revealed the presence of Cd and Te element in the deposited films. The electrical analysis showed linear behavior of current with voltage while conductivity is decreased for higher thickness. The results show that the microstructural and optoelectrical properties of CdTe thin layer could be enhanced by varying thickness and films having higher thickness might be processed as promising absorber thin layer to the CdTe-based solar cells.

  13. Preparation of Basalt Incorporated Polyethylene Composite with Enhanced Mechanical Properties for Various Applications

    Directory of Open Access Journals (Sweden)

    Bredikhin Pavel

    2017-01-01

    Full Text Available The present article showed the possibility of increasing the complex of mechanical properties of polyolefins with dispersed mineral fillers obtained by fine grinding of basalt rocks via ball mill processing. The composites based on dispersed basalt, which were derived from Samara rock mass (Russia with rare earth elements containing, were obtained by extrusion combining the binder and filler, followed by preparation injection-molded test samples. The study of mechanical properties of materials developed showed the possibility of a significant increase in strength characteristics of different types of polyethylene: the breaking stress at static bending for HDPE can be increasing more than 60% and the impact strength by more than 4 times. In addition the incorporation of the dispersed basalt also enhanced the thermal properties of the composites (the oxygen index of HDPE increases from 19 to 25%.

  14. Antioxidant, Antimicrobial and Antiproliferative Activities of Five Lichen Species

    Directory of Open Access Journals (Sweden)

    Snežana Marković

    2011-08-01

    Full Text Available The antioxidative, antimicrobial and antiproliferative potentials of the methanol extracts of the lichen species Parmelia sulcata, Flavoparmelia caperata, Evernia prunastri, Hypogymnia physodes and Cladonia foliacea were evaluated. The total phenolic content of the tested extracts varied from 78.12 to 141.59 mg of gallic acid equivalent (GA/g of extract and the total flavonoid content from 20.14 to 44.43 mg of rutin equivalent (Ru/g of extract. The antioxidant capacities of the lichen extracts were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH radicals scavenging. Hypogymnia physodes with the highest phenolic content showed the strongest DPPH radical scavenging effect. Further, the antimicrobial potential of the lichen extracts was determined by a microdilution method on 29 microorganisms, including 15 strains of bacteria, 10 species of filamentous fungi and 4 yeast species. A high antimicrobial activity of all the tested extracts was observed with more potent inhibitory effects on the growth of Gram (+ bacteria. The highest antimicrobial activity among lichens was demonstrated by Hypogymnia physodes and Cladonia foliacea. Finally, the antiproliferative activity of the lichen extracts was explored on the colon cancer adenocarcinoma cell line HCT-116 by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide viability assay and acridine orange/ethidium bromide staining. The methanol extracts of Hypogymnia physodes and Cladonia foliacea showed a better cytotoxic activity than the other extracts. All lichen species showed the ability to induce apoptosis of HCT-116 cells.

  15. Antiproliferative Activity and Chemical Constituents of Hypericum dyeri. Rehder

    International Nuclear Information System (INIS)

    Ali, M.; Arfan, M.; Zaman, K.

    2013-01-01

    The antiproliferative activity of hexane (F1), ethyl acetate (F2), butanol (F3) and water (F4) extracts of Hypericum dyeri were tested in vitro for their anti- proliferative (anticancer) activity on the cell lines: HT-29 human colon adenocarcinoma, NCI-H460 human non-small cell lung carcinoma, MCF-7 human breast cancer, OVCAR-3 human ovarian adenocarcinoma and RXF-393 human renal cell carcinoma with etoposide as positive control. Among the various extracts the F1 showed relatively potent anti-proliferative activity (IC50, 17.20 +- 4.80 micro g/mL) on NCI-H460 human non-small cell lung carcinoma cell growth. Six compounds were also isolated for the first time from this source. These phytochemicals were identified as 1-Octatriacontanol (1), Hexacosyl tetracosanoate (2), Geddic acid (3), Octacosanoic acid (4), Ceric acid (5) and Sitosterol (6) on the basis of spectroscopic studies such as 1H NMR ,13C NMR, 2D NMR and Mass spectroscopy as well as established with help of reported literature. (author)

  16. Antioxidant, Antimicrobial and Antiproliferative Activities of Five Lichen Species

    Science.gov (United States)

    Mitrović, Tatjana; Stamenković, Slaviša; Cvetković, Vladimir; Tošić, Svetlana; Stanković, Milan; Radojević, Ivana; Stefanović, Olgica; Čomić, Ljiljana; Đačić, Dragana; Ćurčić, Milena; Marković, Snežana

    2011-01-01

    The antioxidative, antimicrobial and antiproliferative potentials of the methanol extracts of the lichen species Parmelia sulcata, Flavoparmelia caperata, Evernia prunastri, Hypogymnia physodes and Cladonia foliacea were evaluated. The total phenolic content of the tested extracts varied from 78.12 to 141.59 mg of gallic acid equivalent (GA)/g of extract and the total flavonoid content from 20.14 to 44.43 mg of rutin equivalent (Ru)/g of extract. The antioxidant capacities of the lichen extracts were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals scavenging. Hypogymnia physodes with the highest phenolic content showed the strongest DPPH radical scavenging effect. Further, the antimicrobial potential of the lichen extracts was determined by a microdilution method on 29 microorganisms, including 15 strains of bacteria, 10 species of filamentous fungi and 4 yeast species. A high antimicrobial activity of all the tested extracts was observed with more potent inhibitory effects on the growth of Gram (+) bacteria. The highest antimicrobial activity among lichens was demonstrated by Hypogymnia physodes and Cladonia foliacea. Finally, the antiproliferative activity of the lichen extracts was explored on the colon cancer adenocarcinoma cell line HCT-116 by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) viability assay and acridine orange/ethidium bromide staining. The methanol extracts of Hypogymnia physodes and Cladonia foliacea showed a better cytotoxic activity than the other extracts. All lichen species showed the ability to induce apoptosis of HCT-116 cells. PMID:21954369

  17. Antiproliferative Activity of Flavonoids from Croton sphaerogynus Baill. (Euphorbiaceae

    Directory of Open Access Journals (Sweden)

    Kátia Pereira dos Santos

    2015-01-01

    Full Text Available Croton sphaerogynus is a shrub from the Atlantic Rain Forest in southeastern Brazil. A lyophilized crude EtOH extract from leaves of C. sphaerogynus, obtained by maceration at room temperature (seven days, was suspended in methanol and partitioned with hexane. The purified MeOH phase was fractionated over Sephadex LH-20 yielding five fractions (F1–F5 containing flavonoids, as characterized by HPLC-DAD and HPLC-MS analyses. The antiproliferative activity of the crude EtOH extract, MeOH and hexane phases, and fractions F1–F5 was evaluated on in vitro cell lines NCI-H460 (nonsmall cell lung, MCF-7 (breast cancer, and U251 (glioma. The MeOH phase showed activity (mean log GI50 0.54 higher than the hexane phase and EtOH extract (mean log GI50 1.13 and 1.19, resp.. F1 exhibited activity against NCI-H460 (nonsmall cell lung (GI50 1.2 μg/mL, which could be accounted for the presence of flavonoids and/or diterpenes. F4 showed moderate activity (mean log GI50 1.05, while F5 showed weak activity (mean log GI50 1.36. It is suggested that the antiproliferative activity of the crude EtOH extract and MeOH phase is accounted for a synergistic combination of flavonoids and diterpenes.

  18. Peptide-Graphene Interactions Enhance the Mechanical Properties of Silk Fibroin.

    Science.gov (United States)

    Cheng, Yuan; Koh, Leng-Duei; Li, Dechang; Ji, Baohua; Zhang, Yingyan; Yeo, Jingjie; Guan, Guijian; Han, Ming-Yong; Zhang, Yong-Wei

    2015-10-07

    Studies reveal that biomolecules can form intriguing molecular structures with fascinating functionalities upon interaction with graphene. Then, interesting questions arise. How does silk fibroin interact with graphene? Does such interaction lead to an enhancement in its mechanical properties? In this study, using large-scale molecular dynamics simulations, we first examine the interaction of graphene with several typical peptide structures of silk fibroin extracted from different domains of silk fibroin, including pure amorphous (P1), pure crystalline (P2), a segment from N-terminal (P3), and a combined amorphous and crystalline segment (P4), aiming to reveal their structural modifications. Our study shows that graphene can have intriguing influences on the structures formed by the peptides with sequences representing different domains of silk fibroin. In general, for protein domains with stable structure and strong intramolecular interaction (e.g., β-sheets), graphene tends to compete with the intramolecular interactions and thus weaken the interchain interaction and reduce the contents of β-sheets. For the silk domains with random or less ordered secondary structures and weak intramolecular interactions, graphene tends to enhance the stability of peptide structures; in particular, it increases the contents of helical structures. Thereafter, tensile simulations were further performed on the representative peptides to investigate how such structure modifications affect their mechanical properties. It was found that the strength and resilience of the peptides are enhanced through their interaction with graphene. The present work reveals interesting insights into the interactions between silk peptides and graphene, and contributes in the efforts to enhance the mechanical properties of silk fibroin.

  19. Enhancing the piezoelectric properties of flexible hybrid AlN materials using semi-crystalline parylene

    Science.gov (United States)

    Jackson, Nathan; Mathewson, Alan

    2017-04-01

    Flexible piezoelectric materials are desired for numerous applications including biomedical, wearable, and flexible electronics. However, most flexible piezoelectric materials are not compatible with CMOS fabrication technology, which is desired for most MEMS applications. This paper reports on the development of a hybrid flexible piezoelectric material consisting of aluminium nitride (AlN) and a semi-crystalline polymer substrate. Various types of semi-crystalline parylene and polyimide materials were investigated as the polymer substrate. The crystallinity and surfaces of the polymer substrates were modified by micro-roughening and annealing in order to determine the effects on the AlN quality. The AlN crystallinity and piezoelectric properties decreased when the polymer surfaces were treated with O2 plasma. However, increasing the crystallinity of the parylene substrate prior to deposition of AlN caused enhanced c-axis (002) AlN crystallinity and piezoelectric response of the AlN. Piezoelectric properties of 200 °C annealed parylene-N substrate resulted in an AlN d 33 value of 4.87 pm V-1 compared to 2.17 pm V-1 for AlN on polyimide and 4.0 pm V-1 for unannealed AlN/parylene-N. The electrical response measurements to an applied force demonstrated that the parylene/AlN hybrid material had higher V pp (0.918 V) than commercial flexible piezoelectric material (PVDF) (V pp 0.36 V). The results in this paper demonstrate that the piezoelectric properties of a flexible AlN hybrid material can be enhanced by increasing the crystallinity of the polymer substrate, and the enhanced properties can function better than previous flexible piezoelectrics.

  20. Enhanced properties of tungsten thin films deposited with a novel HiPIMS approach

    Science.gov (United States)

    Velicu, Ioana-Laura; Tiron, Vasile; Porosnicu, Corneliu; Burducea, Ion; Lupu, Nicoleta; Stoian, George; Popa, Gheorghe; Munteanu, Daniel

    2017-12-01

    Despite the tremendous potential for industrial use of tungsten (W), very few studies have been reported so far on controlling and tailoring the properties of W thin films obtained by physical vapor deposition techniques and, even less, for those deposited by High Power Impulse Magnetron Sputtering (HiPIMS). This study presents results on the deposition process and properties characterization of nanocrystalline W thin films deposited on silicon and molybdenum substrates (100 W average sputtering power) by conventional dc magnetron sputtering (dcMS) and HiPIMS techniques. Topological, structural, mechanical and tribological properties of the deposited thin films were investigated. It was found that in HiPIMS, both deposition process and coatings properties may be optimized by using an appropriate magnetic field configuration and pulsing design. Compared to the other deposited samples, the W films grown in multi-pulse (5 × 3 μs) HiPIMS assisted by an additional magnetic field, created with a toroidal-shaped permanent magnet placed in front of the magnetron cathode, show significantly enhanced properties, such as: smoother surfaces, higher homogeneity and denser microstructure, higher hardness and Young's modulus values, better adhesion to the silicon substrate and lower coefficient of friction. Mechanical behaviour and structural changes are discussed based on plasma diagnostics results.

  1. Carbon-based sputtered coatings for enhanced chitosan-based films properties

    Science.gov (United States)

    Fernandes, C.; Calderon V., S.; Ballesteros, Lina F.; Cerqueira, Miguel A.; Pastrana, L. M.; Teixeira, José A.; Ferreira, P. J.; Carvalho, S.

    2018-03-01

    In order to make bio-based packaging materials competitive in comparison to petroleum-based one, some of their properties need to be improved, among which gas permeability is of crucial importance. Thus, in this work, carbon-based coatings were applied on chitosan-based films by radiofrequency reactive magnetron sputtering aiming to improve their barrier properties. Chemical and morphological properties were evaluated in order to determine the effect of the coatings on the chemical structure, surface hydrophobicity and barrier properties of the system. Chemical analysis, performed by electron energy loss spectroscopy and Fourier transform infrared spectroscopy, suggests similar chemical characteristics among all coatings although higher incorporation of hydrogen as the acetylene flux increases was observed. On the other hand, scanning transmission electron microscopy revealed that the porosity of the carbon layer can be tailored by the acetylene flux. More importantly, the chitosan oxygen permeability showed a monotonic reduction as a function of the acetylene flux. This study opens up new opportunities to apply nanostructured coatings on bio-based polymer for enhanced oxygen barrier properties.

  2. Nanocomposites biodegradable coating on BOPET films to enhance hot seal strength properties

    Energy Technology Data Exchange (ETDEWEB)

    Barbaro, G., E-mail: giovannibarbaro@email.it; Galdi, M. R., E-mail: mrgaldi@unisa.it; Di Maio, L., E-mail: ldimaio@unisa.it; Incarnato, L., E-mail: lincarnato@unisa.it [Industrial Engineering Department, University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano (Italy)

    2015-12-17

    The coating technology is a strategic solution to improve the properties of flexible packaging films. Indeed, additional functional layers are often designed and added as coating on the substrate, in order to improve the characteristic of the flexible packaging and to meet the requirements for the desired gas or vapour barrier, for adhesion and sealing, or for improving the film printability, its aesthetics and durability. Moreover, this technology allows to functionalize a polymeric substrate applying materials with different chemistry, rheology, thermal and structural characteristics. BOPET films are widely used for food packaging applications thanks to their good gas barrier and mechanical properties, high transparency and for the excellent printability. In regard to sealing performance, BOPET films show poor sealing properties so they are mostly submitted to lamination processes with polyethylene. Nevertheless, this solution compromises the PET recyclability and influences the gas permeability of the multilayer PET based structures. The aim of this work is to investigate on the effect of nanocomposite biodegradable coatings for BOPET substrates in enhancing the heat sealing strength of eco-compatible PET/PLA films. At this regards, different percentages of Cloisite C30B (0%, 2% and 4%{sub wt/wt}) have been added to PLA by solution intercalation technique and the nanocomposite biodegradable materials produced have been applied on BOPET commercial films by casting. The BOPET coated films have been characterized in order to evaluate the heat sealing strength and the mechanical, gas permeability and surface properties. The results have shown that the addition of nanoclay in PLA coating significantly enhance the hot tack properties of the PET/PLA system produced, while the oxygen and water vapour permeability are slightly increased if compared to pure BOPET films.

  3. Nanocomposites biodegradable coating on BOPET films to enhance hot seal strength properties

    International Nuclear Information System (INIS)

    Barbaro, G.; Galdi, M. R.; Di Maio, L.; Incarnato, L.

    2015-01-01

    The coating technology is a strategic solution to improve the properties of flexible packaging films. Indeed, additional functional layers are often designed and added as coating on the substrate, in order to improve the characteristic of the flexible packaging and to meet the requirements for the desired gas or vapour barrier, for adhesion and sealing, or for improving the film printability, its aesthetics and durability. Moreover, this technology allows to functionalize a polymeric substrate applying materials with different chemistry, rheology, thermal and structural characteristics. BOPET films are widely used for food packaging applications thanks to their good gas barrier and mechanical properties, high transparency and for the excellent printability. In regard to sealing performance, BOPET films show poor sealing properties so they are mostly submitted to lamination processes with polyethylene. Nevertheless, this solution compromises the PET recyclability and influences the gas permeability of the multilayer PET based structures. The aim of this work is to investigate on the effect of nanocomposite biodegradable coatings for BOPET substrates in enhancing the heat sealing strength of eco-compatible PET/PLA films. At this regards, different percentages of Cloisite C30B (0%, 2% and 4% wt/wt ) have been added to PLA by solution intercalation technique and the nanocomposite biodegradable materials produced have been applied on BOPET commercial films by casting. The BOPET coated films have been characterized in order to evaluate the heat sealing strength and the mechanical, gas permeability and surface properties. The results have shown that the addition of nanoclay in PLA coating significantly enhance the hot tack properties of the PET/PLA system produced, while the oxygen and water vapour permeability are slightly increased if compared to pure BOPET films

  4. Nanocomposites biodegradable coating on BOPET films to enhance hot seal strength properties

    Science.gov (United States)

    Barbaro, G.; Galdi, M. R.; Di Maio, L.; Incarnato, L.

    2015-12-01

    The coating technology is a strategic solution to improve the properties of flexible packaging films. Indeed, additional functional layers are often designed and added as coating on the substrate, in order to improve the characteristic of the flexible packaging and to meet the requirements for the desired gas or vapour barrier, for adhesion and sealing, or for improving the film printability, its aesthetics and durability. Moreover, this technology allows to functionalize a polymeric substrate applying materials with different chemistry, rheology, thermal and structural characteristics. BOPET films are widely used for food packaging applications thanks to their good gas barrier and mechanical properties, high transparency and for the excellent printability. In regard to sealing performance, BOPET films show poor sealing properties so they are mostly submitted to lamination processes with polyethylene. Nevertheless, this solution compromises the PET recyclability and influences the gas permeability of the multilayer PET based structures. The aim of this work is to investigate on the effect of nanocomposite biodegradable coatings for BOPET substrates in enhancing the heat sealing strength of eco-compatible PET/PLA films. At this regards, different percentages of Cloisite C30B (0%, 2% and 4%wt/wt) have been added to PLA by solution intercalation technique and the nanocomposite biodegradable materials produced have been applied on BOPET commercial films by casting. The BOPET coated films have been characterized in order to evaluate the heat sealing strength and the mechanical, gas permeability and surface properties. The results have shown that the addition of nanoclay in PLA coating significantly enhance the hot tack properties of the PET/PLA system produced, while the oxygen and water vapour permeability are slightly increased if compared to pure BOPET films.

  5. Water-processed carbon nanotube/graphene hybrids with enhanced field emission properties

    International Nuclear Information System (INIS)

    Song, Meng; Xu, Peng; Wang, Xu; Wu, Huizhen; Wang, Miao; Song, Yenan; Li, Zhenhua; Zhao, Pei; Shang, Xuefu

    2015-01-01

    Integrating carbon nanotubes (CNTs) and graphene into hybrid structures provides a novel approach to three dimensional (3D) materials with advantageous properties. Here we present a water-processing method to create integrated CNT/graphene hybrids and test their field emission properties. With an optimized mass ratio of CNTs to graphene, the hybrid shows a significantly enhanced field emission performance, such as turn-on electric field of 0.79 V/μm, threshold electric field of 1.05 V/μm, maximum current density of 0.1 mA/cm 2 , and field enhancement factor of ∼1.3 × 10 4 . The optimized mass ratio for field emission emphasizes the importance of both CNTs and graphene in the hybrid. We also hypothesize a possible mechanism for this enhanced field emission performance from the CNT/graphene hybrid. During the solution treatment, graphene oxide behaves as surfactant sheets for CNTs to form a well dispersed solution, which leads to a better organized 3D structure with more conducting channels for electron transport

  6. Enhancement of transport properties of a Brownian particle due to quantum effects: Smoluchowski limit

    International Nuclear Information System (INIS)

    Shit, Anindita; Chattopadhyay, Sudip; Chaudhuri, Jyotipratim Ray

    2012-01-01

    Graphical abstract: By invoking physically motivated coordinate transformation into quantum Smoluchowski equation, we have presented a transparent treatment for the determination of the effective diffusion coefficient and current of a quantum Brownian particle. Substantial enhancement in the efficiency of the diffusive transport is envisaged due to the quantum correction effects. Highlights:: ► Transport of a quantum Brownian particle in a periodic potential has been addressed. ► Governing quantum Smoluchowski equation (QSE) includes state dependent diffusion. ► A coordinate transformation is used to recast QSE with constant diffusion. ► Transport properties increases in comparison to the corresponding classical result. ► This enhancement is purely a quantum effect. - Abstract: The transport property of a quantum Brownian particle that interacts strongly with a bath (in which a typical damping constant by far exceeds a characteristic frequency of the isolated system) under the influence of a tilted periodic potential has been studied by solving quantum Smoluchowski equation (QSE). By invoking physically motivated coordinate transformation into QSE, we have presented a transparent treatment for the determination of the effective diffusion coefficient of a quantum Brownian particle and the current (the average stationary velocity). Substantial enhancement in the efficiency of the diffusive transport is envisaged due to the quantum correction effects only if the bath temperature hovers around an appropriate range of intermediate values. Our findings also confirm the results obtained in the classical cases.

  7. Water-processed carbon nanotube/graphene hybrids with enhanced field emission properties

    Energy Technology Data Exchange (ETDEWEB)

    Song, Meng; Xu, Peng; Wang, Xu; Wu, Huizhen; Wang, Miao, E-mail: peizhao@zju.edu.cn, E-mail: miaowang@css.zju.edu.cn [Department of Physics, Zhejiang University, Hangzhou 310027 (China); Song, Yenan; Li, Zhenhua; Zhao, Pei, E-mail: peizhao@zju.edu.cn, E-mail: miaowang@css.zju.edu.cn [Institute of Applied Mechanics, Zhejiang University, Hangzhou 310027 (China); Shang, Xuefu [Department of Physics, Faculty of Science, Jiangsu University, Zhenjiang 212013 (China)

    2015-09-15

    Integrating carbon nanotubes (CNTs) and graphene into hybrid structures provides a novel approach to three dimensional (3D) materials with advantageous properties. Here we present a water-processing method to create integrated CNT/graphene hybrids and test their field emission properties. With an optimized mass ratio of CNTs to graphene, the hybrid shows a significantly enhanced field emission performance, such as turn-on electric field of 0.79 V/μm, threshold electric field of 1.05 V/μm, maximum current density of 0.1 mA/cm{sup 2}, and field enhancement factor of ∼1.3 × 10{sup 4}. The optimized mass ratio for field emission emphasizes the importance of both CNTs and graphene in the hybrid. We also hypothesize a possible mechanism for this enhanced field emission performance from the CNT/graphene hybrid. During the solution treatment, graphene oxide behaves as surfactant sheets for CNTs to form a well dispersed solution, which leads to a better organized 3D structure with more conducting channels for electron transport.

  8. Synthesis of Curcumin Glycosides with Enhanced Anticancer Properties Using One-Pot Multienzyme Glycosylation Technique.

    Science.gov (United States)

    Gurung, Rit Bahadur; Gong, So Youn; Dhakal, Dipesh; Le, Tuoi Thi; Jung, Na Rae; Jung, Hye Jin; Oh, Tae Jin; Sohng, Jae Kyung

    2017-09-28

    Curcumin is a natural polyphenolic compound, widely acclaimed for its antioxidant, antiinflammatory, antibacterial, and anticancerous properties. However, its use has been limited due to its low-aqueous solubility and poor bioavailability, rapid clearance, and low cellular uptake. In order to assess the effect of glycosylation on the pharmacological properties of curcumin, one-pot multienzyme (OPME) chemoenzymatic glycosylation reactions with UDP- α-D-glucose or UDP-α-D-2-deoxyglucose as donor substrate were employed. The result indicated significant conversion of curcumin to its glycosylated derivatives: curcumin 4'- O -β- glucoside, curcumin 4',4''-di- O -β-glucoside, curcumin 4'- O -β-2-deoxyglucoside, and curcumin 4',4''-di- O -β-2-deoxyglucoside. The products were characterized by ultra-fast performance liquid chromatography, high-resolution quadruple-time-of-flight electrospray ionization-mass spectrometry, and NMR analyses. All the products showed improved water solubility and comparable antibacterial activities. Additionally, the curcumin 4'- O -β-glucoside and curcumin 4'- O -β-2-deoxyglucoside showed enhanced anticancer activities compared with the parent aglycone and diglycoside derivatives. This result indicates that glycosylation can be an effective approach for enhancing the pharmaceutical properties of different natural products, such as curcumin.

  9. Halogenated salicylaldehyde azines: The heavy atom effect on aggregation-induced emission enhancement properties

    International Nuclear Information System (INIS)

    Chen, Xiao-tong; Tong, Ai-jun

    2014-01-01

    This study investigates the heavy-atom effect (HAE) on aggregation-induced emission enhancement (AIEE) properties of salicylaldehyde azines. For this purpose, a series of halogenated salicylaldehyde azine derivatives, namely, chloro-salicylaldehyde azine (1), bromo-salicylaldehyde azine (2) and iodo-salicylaldehyde azine (3) are synthesized. 1 and 2 display typical AIEE characteristics of salicylaldehyde azine compounds; whereas for the iodo-substituent in 3, is found to be effective “external” heavy atom quenchers to salicylaldehyde azine fluorescence in aggregated state. Based on its weak fluorescence in aggregated state and relative strong fluorescence in dispersed state, 3 can also be applied as a turn-on fluorescence probe for egg albumin detection attributed to hydrophobic interaction. -- Highlights: • This study investigates the heavy-atom effect (HAE) on aggregation-induced emission enhancement (AIEE) properties of salicylaldehyde azines. • Chloro- and bromo-salicylaldehyde display typical AIEE properties of salicylaldehyde azine, whereas the iodo-substitute quenches AIEE in aggregated state. • Iodo-salicylaldehyde can be applied as a turn-on fluorescence probe for egg albumin detection attributed to hydrophobic interaction

  10. Enhancing the functional properties and nutritional quality of ice cream with processed amla (Indian gooseberry).

    Science.gov (United States)

    Goraya, Rajpreet Kaur; Bajwa, Usha

    2015-12-01

    Amla (Indian gooseberry) and its processed products are rich source of vitamin C, phenols, dietary fibre and antioxidants. In contrast, ice cream is a poor source of these phytochemicals and antioxidants; therefore, the present investigation was undertaken to enhance the functional properties and nutritional quality of ice cream with the incorporation of processed amla. Ice cream was prepared using amla shreds, pulp, preserve and candy at 5 to 20 % and powder at 0.5 to 2.0 % levels in ice cream mix prior to freezing. Inclusion of amla products at augmented levels resulted in significant changes in physico-chemical properties and phytochemical content of ice cream. The total solids decreased on addition of shreds and pulp and increased with preserve, candy and powder in ice cream at increasing levels. The functional constituents i.e. fibre, total phenols, tannins, ascorbic acid and antioxidant activity increased with greater level of inclusion. Incorporation of processed amla raised the melting resistance of ice cream and decreased the overrun. The samples with 5 % shreds and pulp, 10 % preserve and candy and 0.5 % powder were found to have highest overall acceptability scores. Inclusion of amla in all the forms i.e. shreds, pulp, preserve, candy and powder enhanced the functional properties and nutritional value of ice cream.

  11. Cellulose Acetate/N-TiO2 Biocomposite Flexible Films with Enhanced Solar Photochromic Properties

    Science.gov (United States)

    Radhika, T.; Anju, K. R.; Silpa, M. S.; Ramalingam, R. Jothi; Al-Lohedan, Hamad A.

    2017-07-01

    Flexible cellulose acetate/N-TiO2 nanocomposite films containing various concentrations of nanosized N-TiO2 and an intelligent methylene blue ink have been prepared by solution casting. The hydrothermally prepared nitrogen-doped titania (N-TiO2) and the films were characterized in detail. The photochromic properties of the prepared films were investigated under ultraviolet (UV), visible light, and simulated solar irradiation by UV-Vis spectrophotometry. Upon irradiation, the films exhibited rapid photochromic response that was reversible at room temperature. Films with higher content of nano N-TiO2 showed enhanced decoloration/recoloration under all irradiation conditions, with fast decoloration/recoloration under simulated solar irradiation. These results suggest that the amount of nano N-TiO2 in the composite, the concentration of methylene blue, and the solvent greatly influence the photochromic properties of the films. Such flexible and transparent cellulose acetate/N-TiO2 films with enhanced decoloration/recoloration properties under solar irradiation are promising smart materials for use in photoreversible printed electronics applications.

  12. Site specific replacements of a single loop nucleoside with a dibenzyl linker may switch the activity of TBA from anticoagulant to antiproliferative.

    Science.gov (United States)

    Scuotto, Maria; Rivieccio, Elisa; Varone, Alessia; Corda, Daniela; Bucci, Mariarosaria; Vellecco, Valentina; Cirino, Giuseppe; Virgilio, Antonella; Esposito, Veronica; Galeone, Aldo; Borbone, Nicola; Varra, Michela; Mayol, Luciano

    2015-09-18

    Many antiproliferative G-quadruplexes (G4s) arise from the folding of GT-rich strands. Among these, the Thrombin Binding Aptamer (TBA), as a rare example, adopts a monomolecular well-defined G4 structure. Nevertheless, the potential anticancer properties of TBA are severely hampered by its anticoagulant action and, consequently, no related studies have appeared so far in the literature. We wish to report here that suitable chemical modifications in the TBA sequence can preserve its antiproliferative over anticoagulant activity. Particularly, we replaced one residue of the TT or TGT loops with a dibenzyl linker to develop seven new quadruplex-forming TBA based sequences (TBA-bs), which were studied for their structural (CD, CD melting, 1D NMR) and biological (fibrinogen, PT and MTT assays) properties. The three-dimensional structures of the TBA-bs modified at T13 (TBA-bs13) or T12 (TBA-bs12), the former endowed with selective antiproliferative activity, and the latter acting as potently as TBA in both coagulation and MTT assays, were further studied by 2D NMR restrained molecular mechanics. The comparative structural analyses indicated that neither the stability, nor the topology of the G4s, but the different localization of the two benzene rings of the linker was responsible for the loss of the antithrombin activity for TBA-bs13. © Crown copyright 2015.

  13. Tube-like natural halloysite/poly(tetrafluoroethylene) nanocomposites: simultaneous enhancement in thermal and mechanical properties

    Science.gov (United States)

    Gamini, Suresh; Vasu, V.; Bose, Suryasarathi

    2017-04-01

    In the current study, PTFE (polytetrafluroethylene) matrix is reinforced with different wt% (2%-10%) of Halloysite nanotubes (HNTs). PTFE samples are fabricated with 2 wt% increment and are designated from ‘B’to ‘F’ and designation ‘A’ refers to neat PTFE. Thermal and mechanical characterization of the fabricated composites is studied. The calorimetric measurements showed enhanced degree of crystallinity of the nanocomposites, which is from 57.83% to 74.7%. The dynamic mechanical analysis results have shown enhanced storage modulus and loss modulus and reduced damping behaviour, without affecting glass transition temperature. Moreover, significant improvements in mechanical properties are observed from the experimental results. The results are discussed and validated with the existing literature. The phase and the fracture morphology of the nanocomposites is studied using scanning electron microscope and discussed herein.

  14. Preparation and physical properties of enhanced radiation induced crosslinking of ethylene-vinyl alcohol copolymer (EVOH)

    International Nuclear Information System (INIS)

    Deng Pengyang; Liu Meihua; Zhang Wanxi; Sun Jiazhen

    2007-01-01

    Preparation and physical properties of ethylene-vinyl alcohol copolymer (EVOH) crosslinked by enhanced radiation have been studied through various methods. It was found that the most effective agent for irradiation-crosslinking was triallyl isocyanurate (TAIC) among four kinds of polyfunctional monomers. Gel content (65.6%) was formed for EVOH-44 (content of ethylene is 44 mol%) at 200 kGy with 5% TAIC, but for EVOH-32 (content of ethylene is 32 mol%), only 37.4% gel content was formed under the same conditions. This result showed that the more the content of ethylene units comprised in EVOH, the easier the chemical bonds could be formed between different molecular chains. Tensile strength and elastic modulus increased after crosslinking at high test temperature and elongation at break decreased at the same time. Hygroscopicity of EVOH showed noticeable decrease after enhancement radiation-crosslinking

  15. The magnetic-nanofluid heat pipe with superior thermal properties through magnetic enhancement

    Science.gov (United States)

    2012-01-01

    This study developed a magnetic-nanofluid (MNF) heat pipe (MNFHP) with magnetically enhanced thermal properties. Its main characteristic was additional porous iron nozzle in the evaporator and the condenser to form a unique flowing pattern of MNF slug and vapor, and to magnetically shield the magnet attraction on MNF flowing. The results showed that an optimal thermal conductivity exists in the applied field of 200 Oe. Furthermore, the minor thermal performance of MNF at the condenser limited the thermal conductivity of the entire MNFHP, which was 1.6 times greater than that filled with water for the input power of 60 W. The feasibilities of an MNFHP with the magnetically enhanced heat transfer and the ability of vertical operation were proved for both a promising heat-dissipation device and the energy architecture integrated with an additional energy system. PMID:22716909

  16. The role of polymer dots on efficiency enhancement of organic solar cells: Improving charge transport property

    Science.gov (United States)

    Li, Jinfeng; Zhang, Xinyuan; Liu, Chunyu; Li, Zhiqi; He, Yeyuan; Zhang, Zhihui; Shen, Liang; Guo, Wenbin; Ruan, Shengping

    2017-07-01

    In this work, poly(9,9-dioctylfluorene)-co-(4,7-di-2-thienyl-2,1,3-benzothiadiazole) (PF-5DTBT) and copolymer poly(styrene-co-maleic anhydride) (PSMA) dots were prepared as additive for active layer doping to enhance the power conversion efficiency (PCE) of organic solar cells (OSCs), which based on poly[N-9″-hepta-decanyl-2,7-carbazole-alt-5,5-(4‧,7‧-di-2-thienyl-2‧,1‧,3‧-benzothiadiazole) (PCDTBT) and [6,6]-phenyl C71 butyric acid methyl-ester (PC71BM). A high efficiency of 7.40% was achieved due to increase of short-circuit current (Jsc) and fill factor (FF). The operation mechanism of OSCs doping with polymer dots was investigated, which demonstrated that the efficiency enhancement ascribes to improvement of electrical properties, such as exciton generation, exction dissociation, charge transport, and charge collection.

  17. Ionizing radiation changes the electronic properties of melanin and enhances the growth of melanized fungi.

    Science.gov (United States)

    Dadachova, Ekaterina; Bryan, Ruth A; Huang, Xianchun; Moadel, Tiffany; Schweitzer, Andrew D; Aisen, Philip; Nosanchuk, Joshua D; Casadevall, Arturo

    2007-05-23

    Melanin pigments are ubiquitous in nature. Melanized microorganisms are often the dominating species in certain extreme environments, such as soils contaminated with radionuclides, suggesting that the presence of melanin is beneficial in their life cycle. We hypothesized that ionizing radiation could change the electronic properties of melanin and might enhance the growth of melanized microorganisms. Ionizing irradiation changed the electron spin resonance (ESR) signal of melanin, consistent with changes in electronic structure. Irradiated melanin manifested a 4-fold increase in its capacity to reduce NADH relative to non-irradiated melanin. HPLC analysis of melanin from fungi grown on different substrates revealed chemical complexity, dependence of melanin composition on the growth substrate and possible influence of melanin composition on its interaction with ionizing radiation. XTT/MTT assays showed increased metabolic activity of melanized C. neoformans cells relative to non-melanized cells, and exposure to ionizing radiation enhanced the electron-transfer properties of melanin in melanized cells. Melanized Wangiella dermatitidis and Cryptococcus neoformans cells exposed to ionizing radiation approximately 500 times higher than background grew significantly faster as indicated by higher CFUs, more dry weight biomass and 3-fold greater incorporation of (14)C-acetate than non-irradiated melanized cells or irradiated albino mutants. In addition, radiation enhanced the growth of melanized Cladosporium sphaerospermum cells under limited nutrients conditions. Exposure of melanin to ionizing radiation, and possibly other forms of electromagnetic radiation, changes its electronic properties. Melanized fungal cells manifested increased growth relative to non-melanized cells after exposure to ionizing radiation, raising intriguing questions about a potential role for melanin in energy capture and utilization.

  18. In vitro Antioxidant and Antiproliferative Activities of Various Solvent Fractions from Clerodendrum viscosum Leaves.

    Science.gov (United States)

    Shendge, Anil Khushalrao; Basu, Tapasree; Chaudhuri, Dipankar; Panja, Sourav; Mandal, Nripendranath

    2017-07-01

    Free radicals such as reactive oxygen and nitrogen species, generated in the body, play an important role in the fulfillment of various physiological functions but their imbalance in the body lead to cellular injury and various clinical disorders such as cancer, neurodegenaration, and inflammation. The objective of this study is to fight this problem, natural antioxidant from plants can be considered as possible protective agents against various diseases such as cancer which might also modify the redox microenvironment to reduce the genetic instability. This study was designed to evaluate the antioxidant and antiproliferative potential of Clerodendrum viscosum fractions against various carcinomas. In this present study, 70% methanolic extract of C. viscosum leaves have been fractionated to obtain hexane, chloroform, ethyl acetate, butanol, and water fractions, which were tested for their antioxidant and anticancer properties. It was observed that chloroform and ethyl acetate fractions showed good free radical scavenging properties as well as inhibited the proliferation of human lung cancer (A459), breast (MCF-7), and brain (U87) cells. Moreover, they arrested the cell cycle at G2/M phase of breast and brain cancer. These inhibitory effects were further confirmed by bromodeoxyuridine uptake imaging. Phytochemical investigations further indicate the presence of tannic acid, quercetin, ellagic caid, gallic acid, reserpine, and methyl gallate which might be the reason for these fractions' antioxidant and antiproliferative activities. Clerodendrum viscosum leaf chloroform and Clerodendrum viscosum leaf ethyl acetate fractions from C. viscosum showed good reactive oxygen species and reactive nitrogen species scavenging potential. Both the fractions arrested cell cycle at G2/M phase in MCF-7 and U87 cells which lead to induce apoptosis. Crude extract of Clerodendrum viscosum leaves was fractionated using different solventsAmong them, chloroform and ethyl acetate fractions

  19. Applying Semigroup Property of Enhanced Chebyshev Polynomials to Anonymous Authentication Protocol

    Directory of Open Access Journals (Sweden)

    Hong Lai

    2012-01-01

    Full Text Available We apply semigroup property of enhanced Chebyshev polynomials to present an anonymous authentication protocol. This paper aims at improving security and reducing computational and storage overhead. The proposed scheme not only has much lower computational complexity and cost in the initialization phase but also allows the users to choose their passwords freely. Moreover, it can provide revocation of lost or stolen smart card, which can resist man-in-the-middle attack and off-line dictionary attack together with various known attacks.

  20. Photocured epoxy/graphene nanocomposites with enhanced water vapor barrier properties

    Science.gov (United States)

    Periolatto, M.; Sangermano, M.; Spena, P. Russo

    2016-05-01

    A transparent, water vapor barrier film made of an epoxy resin and graphene oxide (GO) was synthesized by photopolymerization process. The epoxy/GO film with just 0.05 wt% GO gives a 93% WVTR reduction with respect to the pristine polymer, reaching barrier properties better than other polymer composites containing higher amounts of graphene. The excellent water vapor barrier is attributed to the good dispersion of GO in the polymer matrix. Moreover, GO significantly enhances the toughness and the damping capacity of the epoxy resins. The hybrid film can have potential applications in anticorrosive coatings, electronic devices, pharmaceuticals and food packaging.

  1. Thermophysical Properties of Nanoparticle-Enhanced Ionic Liquids (NEILs) Heat-Transfer Fluids

    Energy Technology Data Exchange (ETDEWEB)

    Fox, Elise B.; Visser, Ann E.; Bridges, Nicholas J.; Amoroso, Jake W.

    2013-06-20

    An experimental investigation was completed on nanoparticle enhanced ionic liquid heat transfer fluids as an alternative to conventional organic based heat transfer fluids (HTFs). These nanoparticle-based HTFs have the potential to deliver higher thermal conductivity than the base fluid without a significant increase in viscosity at elevated temperatures. The effect of nanoparticle morphology and chemistry on thermophysical properties was examined. Whisker shaped nanomaterials were found to have the largest thermal conductivity temperature dependence and were also less likely to agglomerate in the base fluid than spherical shaped nanomaterials.

  2. Photocured epoxy/graphene nanocomposites with enhanced water vapor barrier properties

    Energy Technology Data Exchange (ETDEWEB)

    Periolatto, M.; Spena, P. Russo [Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, Bolzano (Italy); Sangermano, M. [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, C.so Duca degli Abruzzi 24, Torino (Italy)

    2016-05-18

    A transparent, water vapor barrier film made of an epoxy resin and graphene oxide (GO) was synthesized by photopolymerization process. The epoxy/GO film with just 0.05 wt% GO gives a 93% WVTR reduction with respect to the pristine polymer, reaching barrier properties better than other polymer composites containing higher amounts of graphene. The excellent water vapor barrier is attributed to the good dispersion of GO in the polymer matrix. Moreover, GO significantly enhances the toughness and the damping capacity of the epoxy resins. The hybrid film can have potential applications in anticorrosive coatings, electronic devices, pharmaceuticals and food packaging.

  3. Photocured epoxy/graphene nanocomposites with enhanced water vapor barrier properties

    International Nuclear Information System (INIS)

    Periolatto, M.; Spena, P. Russo; Sangermano, M.

    2016-01-01

    A transparent, water vapor barrier film made of an epoxy resin and graphene oxide (GO) was synthesized by photopolymerization process. The epoxy/GO film with just 0.05 wt% GO gives a 93% WVTR reduction with respect to the pristine polymer, reaching barrier properties better than other polymer composites containing higher amounts of graphene. The excellent water vapor barrier is attributed to the good dispersion of GO in the polymer matrix. Moreover, GO significantly enhances the toughness and the damping capacity of the epoxy resins. The hybrid film can have potential applications in anticorrosive coatings, electronic devices, pharmaceuticals and food packaging.

  4. Enhancement in photovoltaic properties of silicon solar cells by surface plasmon effect of palladium nanoparticles

    Science.gov (United States)

    Atyaoui, Malek; Atyaoui, Atef; Khalifa, Marwen; Elyagoubi, Jalel; Dimassi, Wissem; Ezzaouia, Hatem

    2016-04-01

    This work presents the surface Plasmon effect of Palladium nanoparticles (Pd NPs) on the photovoltaic properties of silicon solar cells. Pd NPs were deposited on the p-type silicon base of the n+/p junction using a chemical deposition method in an aqueous solution containing Palladium (II) Nitrate (PdNO3)2 and Ammonium Hydroxide (NH4OH) followed by a thermal treatment at 500 °C under nitrogen atmosphere. Chemical composition and surface morphology of the treated silicon base were examined by energy dispersive X-ray (EDX) spectroscopy, scanning electronic microscopy (SEM) and Atomic Force Microscopy (AFM). The effect of the deposited Pd NPs on the electrical properties was evaluated by the internal quantum efficiency (IQE) and current-voltage (I-V) measurements. The results indicate that the formation of the Pd NPs is accompanied by an enhanced light absorption and improved photovoltaic parameters.

  5. Semi-degradable poly(β-amino ester) networks with temporally controlled enhancement of mechanical properties.

    Science.gov (United States)

    Safranski, David L; Weiss, Daiana; Clark, J Brian; Taylor, W Robert; Gall, Ken

    2014-08-01

    Biodegradable polymers are clinically used in numerous biomedical applications, and classically show a loss of mechanical properties within weeks of implantation. This work demonstrates a new class of semi-degradable polymers that show an increase in mechanical properties through degradation via a controlled shift in a thermal transition. Semi-degradable polymer networks, poly(β-amino ester)-co-methyl methacrylate, were formed from a low glass transition temperature crosslinker, poly(β-amino ester), and high glass transition temperature monomer, methyl methacrylate, which degraded in a manner dependent upon the crosslinker chemical structure. In vitro and in vivo degradation revealed changes in mechanical behavior due to the degradation of the crosslinker from the polymer network. This novel polymer system demonstrates a strategy to temporally control the mechanical behavior of polymers and to enhance the initial performance of smart biomedical devices. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  6. Enhancing Microstructure and Mechanical Properties of AZ31-MWCNT Nanocomposites through Mechanical Alloying

    Directory of Open Access Journals (Sweden)

    J. Jayakumar

    2013-01-01

    Full Text Available Multiwall carbon nanotubes (MWCNTs reinforced Mg alloy AZ31 nanocomposites were fabricated by mechanical alloying and powder metallurgy technique. The reinforcement material MWCNTs were blended in three weight fractions (0.33%, 0.66%, and 1% with the matrix material AZ31 (Al-3%, zinc-1% rest Mg and blended through mechanical alloying using a high energy planetary ball mill. Specimens of monolithic AZ31 and AZ31-MWCNT composites were fabricated through powder metallurgy technique. The microstructure, density, hardness, porosity, ductility, and tensile properties of monolithic AZ31 and AZ31-MWCNT nano composites were characterized and compared. The characterization reveals significant reduction in CNT (carbon nanoTube agglomeration and enhancement in microstructure and mechanical properties due to mechanical alloying through ball milling.

  7. Enhanced thermal and mechanical properties of PVA composites formed with filamentous nanocellulose fibrils.

    Science.gov (United States)

    Li, Wei; Wu, Qiong; Zhao, Xin; Huang, Zhanhua; Cao, Jun; Li, Jian; Liu, Shouxin

    2014-11-26

    Long filamentous nanocellulose fibrils (NCFs) were prepared from chemical-thermomechanical pulps (CTMP) using ultrasonication. Their contribution to enhancements in thermal stability and mechanical properties of poly(vinyl alcohol) films were investigated. The unique chemical pretreatment and mechanical effects of CTMP loosen and unfold fibers during the pulping process, which enables further chemical purification and subsequent ultrasound treatment for formation of NCFs. The NCFs exhibited higher crystallinity (72.9%) compared with that of CTMP (61.5%), and had diameters ranging from 50 to 120 nm. A NCF content of 6 wt% was found to yield the best thermal stability, light transmittance, and mechanical properties in the PVA/NCF composites. The composites also exhibited a visible light transmittance of 73.7%, and the tensile strength and Young's modulus were significantly improved, with values 2.8 and 2.4 times larger, respectively, than that of neat PVA. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Hybrid Organic/Inorganic Perovskite–Polymer Nanocomposites: Toward the Enhancement of Structural and Electrical Properties

    KAUST Repository

    Privitera, Alberto

    2017-11-30

    Hybrid organic/inorganic perovskite nanoparticles (NPs) have garnered remarkable research attention because of their promising photophysical properties. New and interesting properties emerge after combining perovskite NPs with semiconducting materials. Here, we report the synthesis and investigation of a composite material obtained by mixing CH3NH3PbBr3 nanocrystals with the semiconducting polymer poly(3-hexylthiophene) (P3HT). By the combination of structural techniques and optical and magnetic spectroscopies we observed multiple effects of the perovskite NPs on the P3HT: (i) an enlargement of P3HT crystalline domains, (ii) a strong p-doping of the P3HT, and (iii) an enhancement of interchain order typical of H-aggregates. These observations open a new avenue toward innovative perovskite NP-based applications.

  9. Enhancement of Electrical Properties of Nanostructured Polysilicon Layers Through Hydrogen Passivation.

    Science.gov (United States)

    Zhou, D; Xu, T; Lambert, Y; Cristini-Robbe; Stiévenard, D

    2015-12-01

    The light absorption of polysilicon planar junctions can be improved using nanostructured top surfaces due to their enhanced light harvesting properties. Nevertheless, associated with the higher surface, the roughness caused by plasma etching and defects located at the grain boundary in polysilicon, the concentration of the recombination centers increases, leading to electrical performance deterioration. In this work, we demonstrate that wet oxidation combined with hydrogen passivation using SiN(x):H are the key technological processes to significantly decrease the surface recombination and improve the electrical properties of nanostructured n(+)-i-p junctions. Nanostructured surface is fabricated by nanosphere lithography in a low-cost and controllable approach. Furthermore, it has been demonstrated that the successive annealing of silicon nitride films has significant effect on the passivation quality, resulting in some improvements on the efficiency of the Si nanostructure-based solar cell device.

  10. Hybrid Organic/Inorganic Perovskite–Polymer Nanocomposites: Toward the Enhancement of Structural and Electrical Properties

    KAUST Repository

    Privitera, Alberto; Righetto, Marcello; de Bastiani, Michele; Carraro, Francesco; Rancan, Marzio; Armelao, Lidia; Granozzi, Gaetano; Bozio, Renato; Franco, Lorenzo

    2017-01-01

    Hybrid organic/inorganic perovskite nanoparticles (NPs) have garnered remarkable research attention because of their promising photophysical properties. New and interesting properties emerge after combining perovskite NPs with semiconducting materials. Here, we report the synthesis and investigation of a composite material obtained by mixing CH3NH3PbBr3 nanocrystals with the semiconducting polymer poly(3-hexylthiophene) (P3HT). By the combination of structural techniques and optical and magnetic spectroscopies we observed multiple effects of the perovskite NPs on the P3HT: (i) an enlargement of P3HT crystalline domains, (ii) a strong p-doping of the P3HT, and (iii) an enhancement of interchain order typical of H-aggregates. These observations open a new avenue toward innovative perovskite NP-based applications.

  11. Enhancing the Properties of Coal Briquette Using Spear Grass (Imperata Cylindrica

    Directory of Open Access Journals (Sweden)

    Adaora Stellamaris OGBUAGU

    2010-12-01

    Full Text Available Studies have been carried out on utilizing agricultural wastes (spear grass to enhance the properties of coal briquette. The proximate analysis of the plant material was carried out alongside with a sample of coal (sub-bituminous coal. Briquettes of different compositions were produced by blending the plant material with the coal at various concentrations: 0%, 10%, 20%, 30%, 40%, 50% and 100%, using cassava starch as a binder and calcium hydroxide (Ca(OH2 as desulfurizing agent. The properties of the briquettes were compared. It was found that the ignition, burning rate and reduction in smoke emission showed improvement with increase in biomass concentration. Compressive strength and cooking efficiency (water boiling time and specific fuel consumption showed initial improvement and rendered to decrease with briquette containing 30% biomass.

  12. Enhancing Mechanical and Thermal Properties of Epoxy Nanocomposites via Alignment of Magnetized SiC Whiskers.

    Science.gov (United States)

    Townsend, James; Burtovyy, Ruslan; Aprelev, Pavel; Kornev, Konstantin G; Luzinov, Igor

    2017-07-12

    This research is focused on the fabrication and properties of epoxy nanocomposites containing magnetized SiC whiskers (MSiCWs). To this end, we report an original strategy for fabrication of magnetically active SiCWs by decorating the whiskers with magnetic (iron oxide) nanoparticles via polymer-polymer (poly(acrylic acid)/poly(2-vinyl pyridine)) complexation. The obtained whiskers demonstrated a substantial magnetic response in the polymerizing epoxy resin, with application of only a 20 mT (200 G) magnetic field. We also found that the whiskers chemically reacted with the epoxy resin, causing formation of an extended interphase near the boundary of the whiskers. The SiC whiskers oriented with the magnetic field demonstrated positive effects on the behavior of epoxy-based nanocomposites. Namely, the aligned MSiCWs enhanced the thermomechanical properties of the materials significantly above that of the neat epoxy and epoxy nanocomposite, with randomly oriented whiskers.

  13. Valorisation of blueberry waste and use of compression to manufacture sustainable starch films with enhanced properties.

    Science.gov (United States)

    Luchese, Cláudia Leites; Uranga, Jone; Spada, Jordana Corralo; Tessaro, Isabel Cristina; de la Caba, Koro

    2018-08-01

    Blueberry waste from juice processing was valorised to develop starch films by compression moulding. The compression process resulted in hydrophobic films with water contact angles even higher than 100° for the films prepared with the highest blueberry waste content. Additionally, the film solubility was reduced by the incorporation of blueberry waste, regardless of the solution pH. These films also exhibited good barrier properties against UV light due to the aromatic compounds present in the blueberry waste. Furthermore, films showed a homogenous surface, although some pores appeared in the cross-section for the films with the highest blueberry waste content. Results highlighted the use of thermo-mechanical processes such as compression to manufacture sustainable films with enhanced properties through waste valorisation by the techniques actually employed at industrial scale. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Enhancement of mechanical properties of a TRIP-aided austenitic stainless steel by controlled reversion annealing

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, A.S., E-mail: atef.hamada@suezuniv.edu.eg [Centre for Advanced Steels Research, Box 4200, University of Oulu, 90014 Oulu (Finland); Metallurgical and Materials Engineering Department, Faculty of Petroleum & Mining Engineering, Suez University, Box 43721, Suez (Egypt); Kisko, A.P. [Centre for Advanced Steels Research, Box 4200, University of Oulu, 90014 Oulu (Finland); Sahu, P. [Department of Physics, Jadavpur University, Kolkata 700032 (India); Karjalainen, L.P. [Centre for Advanced Steels Research, Box 4200, University of Oulu, 90014 Oulu (Finland)

    2015-03-25

    Controlled martensitic reversion annealing was applied to a heavily cold-worked metastable austenitic low-Ni Cr–Mn austenitic stainless steel (Type 201) to obtain different ultrafine austenite grain sizes to enhance the mechanical properties, which were then compared with the conventional coarse-grained steel. Characterization of the deformed and reversion annealed microstructures was performed by electron back scattered diffraction (EBSD), X-ray diffraction (XRD) and light and transmission electron microscopy (TEM). The steel with a reverted grain size ~1.5 μm due to annealing at 800 °C for 10 s showed significant improvements in the mechanical properties with yield stress ~800 MPa and tensile strength ~1100 MPa, while the corresponding properties of its coarse grained counterpart were ~450 MPa and ~900 MPa, respectively. However, the fracture elongation of the reversion annealed steel was ~50% as compared to ~70% in the coarse grained steel. A further advantage is that the anisotropy of mechanical properties present in work-hardened steels also disappears during reversion annealing.

  15. Short-Term Changes in Physical and Chemical Properties of Soil Charcoal Support Enhanced Landscape Mobility

    Science.gov (United States)

    Pyle, Lacey A.; Magee, Kate L.; Gallagher, Morgan E.; Hockaday, William C.; Masiello, Caroline A.

    2017-11-01

    Charcoal is a major component of the stable soil organic carbon reservoir, and the physical and chemical properties of charcoal can sometimes significantly alter bulk soil properties (e.g., by increasing soil water holding capacity). However, our understanding of the residence time of soil charcoal remains uncertain, with old measured soil charcoal ages in apparent conflict with relatively short modeled and measured residence times. These discrepancies may exist because the fate of charcoal on the landscape is a function not just of its resistance to biological decomposition but also its physical mobility. Mobility may be important in controlling charcoal landscape residence time and may artificially inflate estimates of its degradability, but few studies have examined charcoal vulnerability to physical redistribution. Charcoal landscape redistribution is likely higher than other organic carbon fractions owing to charcoal's low bulk density, typically less than 1.0 g/cm3. Here we examine both the physical and chemical properties of soil and charcoal over a period of two years following a 2011 wildfire in Texas. We find little change in properties with time; however, we find evidence of enhanced mobility of charcoal relative to other forms of soil organic matter. These data add to a growing body of evidence that charcoal is preferentially eroded, offering another explanation for variations observed in its environmental residence times.

  16. Antiproliferative Activity of Hamigerone and Radicinol Isolated from Bipolaris papendorfii

    Directory of Open Access Journals (Sweden)

    Periyasamy Giridharan

    2014-01-01

    Full Text Available Secondary metabolites from fungi organisms have extensive past and present use in the treatment of many diseases and serve as compounds of interest both in their natural form and as templates for synthetic modification. Through high throughput screening (HTS and bioassay-guided isolation, we isolated two bioactive compounds hamigerone (1 and radicinol (2. These compounds were isolated from fungus Bipolaris papendorfii, isolated from the rice fields of Dera, Himachal Pradesh, India. The structures of the compounds were established on the basis of spectroscopic data, namely, NMR (1H, 13C, mass, and UV. Both compounds were found to be antiproliferative against different cancer cells. Furthermore we have also noted that both compounds showed increase in apoptosis by favorably modulating both tumor suppressor protein (p53 and antiapoptic protein (BCL-2, and in turn increase caspase-3 expression in cancer cells. This is the first report of these compounds from fungus Bipolaris papendorfii and their anticancer activity.

  17. A green multicomponent synthesis of tocopherol analogues with antiproliferative activities.

    Science.gov (United States)

    Ingold, Mariana; Dapueto, Rosina; Victoria, Sabina; Galliusi, Germán; Batthyàny, Carlos; Bollati-Fogolín, Mariela; Tejedor, David; García-Tellado, Fernando; Padrón, José M; Porcal, Williams; López, Gloria V

    2018-01-01

    A one-pot efficient, practical and eco-friendly synthesis of tocopherol analogues has been developed using water or solvent free conditions via Passerini and Ugi multicomponent reactions. These reactions can be optimized using microwave irradiation or ultrasound as the energy source. Accordingly, a small library of 30 compounds was prepared for biological tests. The evaluation of the antiproliferative activity in the human solid tumor cell lines A549 (lung), HBL-100 (breast), HeLa (cervix), SW1573 (lung), T-47D (breast), and WiDr (colon) provided lead compounds with GI 50 values between 1 and 5 μM. A structure-activity relationship is also discussed. One of the studied compounds comes up as a future candidate for the development of potent tocopherol-mimetic therapeutic agents for cancer. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  18. In vitro anti-proliferative effect of interferon alpha in solid tumors: A potential predicative test

    International Nuclear Information System (INIS)

    Fuchsberger, N.; Kubes, M.; Kontsek, P.; Borecky, L.; Hornak, M.; Silvanova; Godal, A.; Svec, J.

    1993-01-01

    An in vitro test for the anti-proliferative effect of human leukocyte interferon (IFN-alpha) was performed in primary cultures of tumor cells obtained from 32 patients with either malignant melanoma (13), renal carcinoma (4) or bladder carcinoma (15). Our results demonstrated activity of IFN in all three groups of solid tumors. However, appreciable differences in sensitivity to anti-proliferative effect of IFN between individual tumors of the same type were found. The potential of this anti-proliferative test for prediction of treatment response in IFN-therapy is discussed. (author)

  19. The antiproliferative effect of acridone alkaloids on several cancer cell lines.

    Science.gov (United States)

    Kawaii, S; Tomono, Y; Katase, E; Ogawa, K; Yano, M; Takemura, Y; Ju-ichi, M; Ito, C; Furukawa, H

    1999-04-01

    Fifteen acridone alkaloids were examined for their antiproliferative activity toward monolayers and suspension of several types of cancer and normal human cell lines. As a result, atalaphyllidine (9), 5-hydroxy-N-methylseverifoline (11), atalaphyllinine (12), and des-N-methylnoracronycine (13) showed potent antiproliferative activity against tumor cell lines, whereas they have weak cytotoxicity on normal human cell lines. The structure-activity relationship established from the results revealed that a secondary amine, hydroxyl groups at C-1 and C-5, and a prenyl group at C-2 played an important role for antiproliferative activities of the tetracyclic acridones.

  20. A synthetic cryptochrome inhibitor induces anti-proliferative effects and increases chemosensitivity in human breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Sung Kook [Department of Brain & Cognitive Sciences, Daegu-Gyeongbuk Institute of Science & Technology, Daegu, 711-873 (Korea, Republic of); Department of Biological Sciences, Seoul National University, Seoul, 151-747 (Korea, Republic of); Department of Brain & Cognitive Sciences, Seoul National University, Seoul, 151-747 (Korea, Republic of); Chung, Sooyoung [Department of Biological Sciences, Seoul National University, Seoul, 151-747 (Korea, Republic of); Department of Biomedical Sciences, College of Medicine, Korea University, Seoul, 136-705 (Korea, Republic of); Kim, Hee-Dae [Department of Biological Sciences, Seoul National University, Seoul, 151-747 (Korea, Republic of); Lee, Ju Hyung [Department of Systems Biology, Yonsei University College of Life Science and Biotechnology, Seoul 120-749 (Korea, Republic of); Jang, Jaebong [College of Pharmacy, Seoul National University, Seoul, 151-742 (Korea, Republic of); Kim, Jeongah; Kim, Doyeon [Department of Brain & Cognitive Sciences, Daegu-Gyeongbuk Institute of Science & Technology, Daegu, 711-873 (Korea, Republic of); Department of Biological Sciences, Seoul National University, Seoul, 151-747 (Korea, Republic of); Department of Brain & Cognitive Sciences, Seoul National University, Seoul, 151-747 (Korea, Republic of); Son, Gi Hoon [Department of Biomedical Sciences, College of Medicine, Korea University, Seoul, 136-705 (Korea, Republic of); Oh, Young J. [Department of Systems Biology, Yonsei University College of Life Science and Biotechnology, Seoul 120-749 (Korea, Republic of); Suh, Young-Ger [College of Pharmacy, Seoul National University, Seoul, 151-742 (Korea, Republic of); Lee, Cheol Soon [Gachon Clinical Trials Center, Gachon University, Incheon, 417-842 (Korea, Republic of); and others

    2015-11-13

    Disruption of circadian rhythm is a major cause of breast cancer in humans. Cryptochrome (CRY), a circadian transcription factor, is a risk factor for initiation of breast cancer, and it is differentially expressed between normal and breast cancer tissues. Here, we evaluated the anti-proliferative and pro-apoptotic activity of KS15, a recently discovered small-molecule inhibitor of CRY, in human breast cancer cells. First, we investigated whether KS15 treatment could promote E-box-mediated transcription by inhibiting the activity of CRY in MCF-7 human breast cancer cells. Protein and mRNA levels of regulators of cell cycle and apoptosis, as well as core clock genes, were differentially modulated in response to KS15. Next, we investigated whether KS15 could inhibit proliferation and increase sensitivity to anti-tumor drugs in MCF-7 cells. We found that KS15 decreased the speed of cell growth and increased the chemosensitivity of MCF-7 cells to doxorubicin and tamoxifen, but had no effect on MCF-10A cells. These findings suggested that pharmacological inhibition of CRY by KS15 exerts an anti-proliferative effect and increases sensitivity to anti-tumor drugs in a specific type of breast cancer. - Highlights: • Cryptochrome inhibitor (KS15) has anti-tumor activity to human breast cancer cells. • KS15 induces differential changes in cell cycle regulators and pro-apoptotic genes. • KS15 inhibits MCF-7 cell growth and enhances susceptibility to anti-tumor drugs.

  1. Curcumin Conjugated with PLGA Potentiates Sustainability, Anti-Proliferative Activity and Apoptosis in Human Colon Carcinoma Cells

    Science.gov (United States)

    Waghela, Bhargav N.; Sharma, Anupama; Dhumale, Suhashini; Pandey, Shashibahl M.; Pathak, Chandramani

    2015-01-01

    Curcumin, an ingredient of turmeric, exhibits a variety of biological activities such as anti-inflammatory, anti-atherosclerotic, anti-proliferative, anti-oxidant, anti-cancer and anti-metastatic. It is a highly pleiotropic molecule that inhibits cell proliferation and induces apoptosis in cancer cells. Despite its imperative biological activities, chemical instability, photo-instability and poor bioavailability limits its utilization as an effective therapeutic agent. Therefore, enhancing the bioavailability of curcumin may improve its therapeutic index for clinical setting. In the present study, we have conjugated curcumin with a biodegradable polymer Poly (D, L-lactic-co-glycolic acid) and evaluated its apoptotic potential in human colon carcinoma cells (HCT 116). The results show that curcumin-PLGA conjugate efficiently inhibits cell proliferation and cell survival in human colon carcinoma cells as compared to native curcumin. Additionally, curcumin conjugated with PLGA shows improved cellular uptake and exhibits controlled release at physiological pH as compared to native curcumin. The curcumin-PLGA conjugate efficiently activates the cascade of caspases and promotes intrinsic apoptotic signaling. Thus, the results suggest that conjugation potentiates the sustainability, anti-proliferative and apoptotic activity of curcumin. This approach could be a promising strategy to improve the therapeutic index of cancer therapy. PMID:25692854

  2. A synthetic cryptochrome inhibitor induces anti-proliferative effects and increases chemosensitivity in human breast cancer cells

    International Nuclear Information System (INIS)

    Chun, Sung Kook; Chung, Sooyoung; Kim, Hee-Dae; Lee, Ju Hyung; Jang, Jaebong; Kim, Jeongah; Kim, Doyeon; Son, Gi Hoon; Oh, Young J.; Suh, Young-Ger; Lee, Cheol Soon

    2015-01-01

    Disruption of circadian rhythm is a major cause of breast cancer in humans. Cryptochrome (CRY), a circadian transcription factor, is a risk factor for initiation of breast cancer, and it is differentially expressed between normal and breast cancer tissues. Here, we evaluated the anti-proliferative and pro-apoptotic activity of KS15, a recently discovered small-molecule inhibitor of CRY, in human breast cancer cells. First, we investigated whether KS15 treatment could promote E-box-mediated transcription by inhibiting the activity of CRY in MCF-7 human breast cancer cells. Protein and mRNA levels of regulators of cell cycle and apoptosis, as well as core clock genes, were differentially modulated in response to KS15. Next, we investigated whether KS15 could inhibit proliferation and increase sensitivity to anti-tumor drugs in MCF-7 cells. We found that KS15 decreased the speed of cell growth and increased the chemosensitivity of MCF-7 cells to doxorubicin and tamoxifen, but had no effect on MCF-10A cells. These findings suggested that pharmacological inhibition of CRY by KS15 exerts an anti-proliferative effect and increases sensitivity to anti-tumor drugs in a specific type of breast cancer. - Highlights: • Cryptochrome inhibitor (KS15) has anti-tumor activity to human breast cancer cells. • KS15 induces differential changes in cell cycle regulators and pro-apoptotic genes. • KS15 inhibits MCF-7 cell growth and enhances susceptibility to anti-tumor drugs.

  3. Evaluation of the Volatile Oil Composition and Antiproliferative Activity of Laurus nobilis L. (Lauraceae on Breast Cancer Cell Line Models

    Directory of Open Access Journals (Sweden)

    Rana Abu-Dahab

    2014-03-01

    Full Text Available Volatile oil composition and antiproliferative activity of Laurus nobilis L. (Lauraceae fruits and leaves grown in Jordan were investigated. GC-MS analysis of the essential oil of the fruits resulted in the identification of 45 components representing 99.7 % of the total oil content, while the leaf essential oil yielded 37 compounds representing 93.7% of the total oil content. Oxygenated monoterpene 1,8-cineole was the main component in the fruit and leaf oils. Using sulphorhodamine B assay; the crude ethanol fraction, among other solvent extracts, showed strong antiproliferative activity for both leaves and fruits, nevertheless, the fruits were more potent against both breast cancer cell models (MCF7 and T47D. At IC 50 values ; the mechanism of apoptosis was nevertheless different: where L. nobilis fruit proapoptotic efficacy was not regulated by either p53 or p21, L. nobilis leaf extract components enhanced the p53 levels substantially. In both extracts, apoptosis was not caspase-8 or Fas Ligand and sFas (Fas/APO-1 dependent. Our studies highlight L. nobilis as a potential natural agent for breast cancer therapy. Compared with non induced basal cells, both L. nobilis fruits and leaves induced a significant enrichment in the cytoplasmic mono- and oligonucleosomes after assumed induction of programmed MCF7 cell death.

  4. Analysis of Flavonoids in Rhamnus davurica and Its Antiproliferative Activities

    Directory of Open Access Journals (Sweden)

    Guilin Chen

    2016-09-01

    Full Text Available Rhamnus davurica Pall. (R. davurica has been used as a traditional medicinal herb for many years in China and abroad. It has been well documented as a rich source of flavonoids with diversified structures, which in turn results in far-ranging biological activities, such as anti-inflammation, anticancer, antibacterial and antioxidant activities. In order to further correlate their anticancer potentials with the phytochemical components, the fingerprint profile of R. davurica herb from Dongbei was firstly investigated using HPLC-ESI-MS/MS. Thirty two peaks were detected and identified, 14 of which were found in R. davurica for the first time in this work. Furthermore, a total of 23 peaks were resolved as flavonoids, which are the major components found in R. davurica. Meanwhile, the antiproliferative activities against human cancer cells of HT-29 and SGC-7901 in vitro exhibited distinct inhibitory effects with IC50 values at 24.96 ± 0.74 and 89.53 ± 4.11 μg/mL, respectively. Finally, the general toxicity against L-O2 cells displayed a much higher IC50 at 229.19 ± 8.52 μg/mL, which suggested very low or no toxicity on hepatic cell viability. The current study revealed for the first time the correlations between the flavonoids of R. davurica with their antiproliferative activities, which indicated that the fingerprint profile of flavonoids and their anticancer activities could provide valuable information on the quality control for herbal medicines and their derived natural remedies from this valuable medicinal plant.

  5. Photo-physical properties enhancement of bare and core-shell quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Mumin, Md Abdul, E-mail: pcharpentier@eng.uwo.ca; Akhter, Kazi Farida, E-mail: pcharpentier@eng.uwo.ca; Charpentier, Paul A., E-mail: pcharpentier@eng.uwo.ca [Chemical and Biochemical Engineering, Western University, London Ontario (Canada)

    2014-03-31

    Semiconductor nanocrystals (NCs) (also known as quantum dots, QDs) have attracted immense attention for their size-tunable optical properties that makes them impressive candidates for solar cells, light emitting devices, lasers, as well as biomedical imaging. However monodispersity, high and consistent photoluminescence, photostability, and biocompatibility are still major challenges. This work focuses on optimizing the photophysical properties and biocompatibility of QDs by forming core-shell nanostructures and their encapsulation by a carrier. Highly luminescent CdS and CdS-ZnS core-shell QDs with 5 nm sizes were synthesized using a facile approach based on pyrolysis of the single molecule precursors. After capping the CdS QDs with a thin layer of ZnS to reduce toxicity, the photoluminescence and photostability of the core-shell QDs was significantly enhanced. To make both the bare and core/shell structure QDs more resistant against photochemical reactions, a mesoporous silica layer was grown on the QDs through a reverse microemulsion technique based on hydrophobic interaction. This encapsulation enhanced the quantum yield and photostability compared to the bare QDs by providing much stronger resistance to oxidation and Oswald ripening of QDs. Encapsulation also improved biocompatibility of QDs that was evaluated with human umbilical vein endothelial cell lines (HUVEC)

  6. Enhanced functional connectivity properties of human brains during in-situ nature experience

    Directory of Open Access Journals (Sweden)

    Zheng Chen

    2016-07-01

    Full Text Available In this study, we investigated the impacts of in-situ nature and urban exposure on human brain activities and their dynamics. We randomly assigned 32 healthy right-handed college students (mean age = 20.6 years, SD = 1.6; 16 males to a 20 min in-situ sitting exposure in either a nature (n = 16 or urban environment (n = 16 and measured their Electroencephalography (EEG signals. Analyses revealed that a brief in-situ restorative nature experience may induce more efficient and stronger brain connectivity with enhanced small-world properties compared with a stressful urban experience. The enhanced small-world properties were found to be correlated with “coherent” experience measured by Perceived Restorativeness Scale (PRS. Exposure to nature also induces stronger long-term correlated activity across different brain regions with a right lateralization. These findings may advance our understanding of the functional activities during in-situ environmental exposures and imply that a nature or nature-like environment may potentially benefit cognitive processes and mental well-being.

  7. Enhanced functional connectivity properties of human brains during in-situ nature experience.

    Science.gov (United States)

    Chen, Zheng; He, Yujia; Yu, Yuguo

    2016-01-01

    In this study, we investigated the impacts of in-situ nature and urban exposure on human brain activities and their dynamics. We randomly assigned 32 healthy right-handed college students (mean age = 20.6 years, SD = 1.6; 16 males) to a 20 min in-situ sitting exposure in either a nature (n = 16) or urban environment (n = 16) and measured their Electroencephalography (EEG) signals. Analyses revealed that a brief in-situ restorative nature experience may induce more efficient and stronger brain connectivity with enhanced small-world properties compared with a stressful urban experience. The enhanced small-world properties were found to be correlated with "coherent" experience measured by Perceived Restorativeness Scale (PRS). Exposure to nature also induces stronger long-term correlated activity across different brain regions with a right lateralization. These findings may advance our understanding of the functional activities during in-situ environmental exposures and imply that a nature or nature-like environment may potentially benefit cognitive processes and mental well-being.

  8. Aluminum oxide barrier coating on polyethersulfone substrate by atomic layer deposition for barrier property enhancement

    International Nuclear Information System (INIS)

    Kim, Hyun Gi; Kim, Sung Soo

    2011-01-01

    Aluminum oxide layers were deposited on flexible polyethersulfone (PES) substrates via plasma enhanced atomic layer deposition (PEALD) process using trimethylaluminum (TMA) and oxygen as precursor and reactant materials. Several process parameters in PEALD process were investigated in terms of refractive index and layer thickness. Number of process cycle increased the thickness and refractive index of the layer to enhance the barrier properties. Non-physisorbed TMA and unreacted oxygen were purged before and after the plasma reaction, respectively. Identical purge time was applied to TMA and oxygen and it was optimized for 10 s. Thinner and denser layer was formed as substrate temperature increased. However, the PES substrate could be deformed above 120 o C. Aluminum oxide layer formed on PES at optimized conditions have 11.8 nm of thickness and reduced water vapor transmission rate and oxygen transmission rate to below 4 x 10 -3 g/m 2 day and 4 x 10 -3 cm 3 /m 2 day, respectively. Polycarbonate and polyethylene naphthalate films were also tested at optimized conditions, and they also showed quite appreciable barrier properties to be used as plastic substrates.

  9. Nest-like structures of Sr doped Bi2WO6: Synthesis and enhanced photocatalytic properties

    International Nuclear Information System (INIS)

    Liu Ying; Wang Weimin; Fu Zhengyi; Wang Hao; Wang Yucheng; Zhang Jinyong

    2011-01-01

    Highlights: → Bi 2 WO 6 with 3D nest-like structures was obtained without the presence of templates but after Sr-doping, which represents a marked improvement over previous reports. → The products showed enhanced photocatalytic properties over pure Bi 2 WO 6 . → Samples subsequently thermal treated at 500 deg. C show better photocatalytic activities. - Abstract: A series of Sr-doped Bi 2 WO 6 with three-dimensional (3D) nest-like structures were synthesized through simple hydrothermal route and characterized by XRD, FESEM, TEM, XPS, UV-vis DRS, etc. Morphology observation revealed that the as-synthesized Bi 2 WO 6 were self-assembled three-dimensional (3D) nest-like structures, which were constructed from nanoplates. UV-vis diffuse reflectance spectra indicated that the samples had absorption in both UV and visible light areas. Their photocatalytic activities were evaluated by photodegradation of rhodamine B (RhB) under UV and visible light irradiation (λ > 420 nm). The photocatalytic properties were enhanced after Sr doping. Samples subsequently thermal treated at 500 deg. C showed higher photocatalytic activities. The reasons for the differences in the photocatalytic activities of these nest-like Bi 2 WO 6 microstructures were further investigated.

  10. Enhancing the functional properties of thermophilic enzymes by chemical modification and immobilization.

    Science.gov (United States)

    Cowan, Don A; Fernandez-Lafuente, Roberto

    2011-09-10

    The immobilization of proteins (mostly typically enzymes) onto solid supports is mature technology and has been used successfully to enhance biocatalytic processes in a wide range of industrial applications. However, continued developments in immobilization technology have led to more sophisticated and specialized applications of the process. A combination of targeted chemistries, for both the support and the protein, sometimes in combination with additional chemical and/or genetic engineering, has led to the development of methods for the modification of protein functional properties, for enhancing protein stability and for the recovery of specific proteins from complex mixtures. In particular, the development of effective methods for immobilizing large multi-subunit proteins with multiple covalent linkages (multi-point immobilization) has been effective in stabilizing proteins where subunit dissociation is the initial step in enzyme inactivation. In some instances, multiple benefits are achievable in a single process. Here we comprehensively review the literature pertaining to immobilization and chemical modification of different enzyme classes from thermophiles, with emphasis on the chemistries involved and their implications for modification of the enzyme functional properties. We also highlight the potential for synergies in the combined use of immobilization and other chemical modifications. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. Diatomite as a novel composite ingredient for chitosan film with enhanced physicochemical properties.

    Science.gov (United States)

    Akyuz, Lalehan; Kaya, Murat; Koc, Behlul; Mujtaba, Muhammad; Ilk, Sedef; Labidi, Jalel; Salaberria, Asier M; Cakmak, Yavuz Selim; Yildiz, Aysegul

    2017-12-01

    Practical applications of biopolymers in different industries are gaining considerable increase day by day. But still, these biopolymers lack important properties in order to meet the industrial demands. In the same regard, in the current study, chitosan composite films are produced by incorporating diatomite soil at two different concentrations. In order to obtain a homogeneous film, glutaraldehyde was supplemented to chitosan solution as a cross-linker. Compositing diatomaceous earth to chitosan film resulted in improvement of various important physicochemical properties compared to control such as; enhanced film wettability, increase elongation at break and improved thermal stability (264-277°C). The microstructure of the film was observed to haveconsisted of homogeneously distributed blister-shaped structures arised due to the incorporation of diatomite. The incorporation of diatomite did not influence the overall antioxidant activity of the composite films, which can be ascribe to the difficulty radicals formation. Chitosan film incorporated with increasing fraction of diatomite revealed a notable enhancement in the antimicrobial activity. Additionally with the present study, for the first time possible interactions between chitosan/diatomite were determined via quantum chemical calculations. Current study will be helpful in giving a new biotechnological perspective to diatom in terms of its successful application in hydrophobic composite film production. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Enhanced antimicrobial properties, cytocompatibility, and corrosion resistance of plasma-modified biodegradable magnesium alloys.

    Science.gov (United States)

    Zhao, Ying; Jamesh, Mohammed Ibrahim; Li, Wing Kan; Wu, Guosong; Wang, Chenxi; Zheng, Yufeng; Yeung, Kelvin W K; Chu, Paul K

    2014-01-01

    Magnesium alloys are potential biodegradable materials and have received increasing attention due to their outstanding biological performance and mechanical properties. However, rapid degradation in the physiological environment and potential toxicity limit clinical applications. Recently, special magnesium-calcium (Mg-Ca) and magnesium-strontium (Mg-Sr) alloys with biocompatible chemical compositions have been reported, but the rapid degradation still does not meet clinical requirements. In order to improve the corrosion resistance, a rough, hydrophobic and ZrO(2)-containing surface film is fabricated on Mg-Ca and Mg-Sr alloys by dual zirconium and oxygen ion implantation. Weight loss measurements and electrochemical corrosion tests show that the corrosion rate of the Mg-Ca and Mg-Sr alloys is reduced appreciably after surface treatment. A systematic investigation of the in vitro cellular response and antibacterial capability of the modified binary magnesium alloys is performed. The amounts of adherent bacteria on the Zr-O-implanted and Zr-implanted samples diminish remarkably compared to the unimplanted control. In addition, significantly enhanced cell adhesion and proliferation are observed from the Zr-O-implanted sample. The results suggest that dual zirconium and oxygen ion implantation, which effectively enhances the corrosion resistance, in vitro biocompatibility and antimicrobial properties of Mg-Ca and Mg-Sr alloys, provides a simple and practical means to expedite clinical acceptance of biodegradable magnesium alloys. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  13. Synergistic effect of Al and Gd on enhancement of mechanical properties of magnesium alloys

    Directory of Open Access Journals (Sweden)

    Bita Pourbahari

    2017-04-01

    Full Text Available The effect of Gd/Al ratio on the properties of as-cast Mg-Gd-Al-Zn alloys was investigated by changing the chemical composition from that of AZ61 to GZ61. At the ratio of 1, the Al2Gd phase becomes predominant and Mg17Al12 is hardly seen in the microstructure. As a potent inoculant, the Al2Gd phase resulted in intense grain refinement and enhancement of strength, ductility and toughness. For instance, the tensile strength and elongation to failure of Mg-3Gd-3Al-1Zn alloy were enhanced by ~4% and 180% compared with those of AZ61 alloy, respectively. However, at high Gd/Al ratios, the Al2Gd phase was replaced by (Mg,Al3Gd and Mg5Gd phases and very large grain sizes were achieved, which led to poor tensile properties and the appearance of cleavage facets on the fracture surfaces. Therefore, it can be deduced that the presence of Gd and Al, in appropriate amounts to reach Gd/Al ratio of ~ 1, is required for the achievement of grain refinement, good ductility, high strength, and the appearance of ductile fracture surfaces in the Mg-Gd-Al-Zn system. Conclusively, the Mg-Gd-Al-Zn alloys can be considered as a new class of structural magnesium alloy and it is superior to both AZ (Mg-Al-Zn and GZ (Mg-Gd-Zn series of alloys.

  14. The Acetone Extract of Sclerocarya birrea (Anacardiaceae) Possesses Antiproliferative and Apoptotic Potential against Human Breast Cancer Cell Lines (MCF-7)

    Science.gov (United States)

    Tanih, Nicoline Fri; Ndip, Roland Ndip

    2013-01-01

    Interesting antimicrobial data from the stem bark of Sclerocarya birrea, which support its use in traditional medicine for the treatment of many diseases, have been delineated. The current study was aimed to further study some pharmacological and toxicological properties of the plant to scientifically justify its use. Anticancer activity of water and acetone extracts of S. birrea was evaluated on three different cell lines, HT-29, HeLa, and MCF-7 using the cell titre blue viability assay in 96-well plates. Apoptosis was evaluated using the acridine orange and propidium iodide staining method, while morphological structure of treated cells was examined using SEM. The acetone extract exhibited remarkable antiproliferative activities on MCF-7 cell lines at dose- and time-dependent manners (24 h and 48 h of incubation). The extract also exerted apoptotic programmed cell death in MCF-7 cells with significant effect on the DNA. Morphological examination also displayed apoptotic characteristics in the treated cells, including clumping, condensation, and culminating to budding of the cells to produce membrane-bound fragmentation, as well as formation of apoptotic bodies. The acetone extract of S. birrea possesses antiproliferative and apoptotic potential against MCF-7-treated cells and could be further exploited as a potential lead in anticancer therapy. PMID:23576913

  15. 76 FR 72046 - Enhanced-Use Lease (EUL) of Department of Veterans Affairs (VA) Real Property for the Development...

    Science.gov (United States)

    2011-11-21

    ... DEPARTMENT OF VETERANS AFFAIRS Enhanced-Use Lease (EUL) of Department of Veterans Affairs (VA) Real Property for the Development of Space for Community Services and Parking in Memphis, TN AGENCY... property is located. This project meets this requirement. Approved: November 14, 2011. Eric K. Shinseki...

  16. 76 FR 72048 - Enhanced-Use Lease (EUL) of Department of Veterans Affairs (VA) Real Property for the Development...

    Science.gov (United States)

    2011-11-21

    ... DEPARTMENT OF VETERANS AFFAIRS Enhanced-Use Lease (EUL) of Department of Veterans Affairs (VA) Real Property for the Development of Permanent Housing in Grand Island, NE AGENCY: Department of... property is located. This project meets this requirement. Approved: November 14, 2011. Eric K. Shinseki...

  17. Cellulose nanocrystal/polyolefin biocomposites prepared by solid-state shear pulverization: Superior dispersion leading to synergistic property enhancements

    Science.gov (United States)

    Krishnan A. Iyer; Gregory T. Schueneman; John M. Torkelson

    2015-01-01

    Cellulose nanocrystals (CNCs), a class of renewable bionanomaterials with excellent mechanical properties, have gained major interest as filler for polymers. However, challenges associated with effective CNC dispersion have hindered the production of composites with desired property enhancements. Here, composites of polypropylene (PP) and low density polyethylene (LDPE...

  18. Evaluation of Anti-Wear Properties of Metalworking Fluids Enhanced with Halloysite Nanotubes

    Directory of Open Access Journals (Sweden)

    Laura Peña-Parás

    2017-10-01

    Full Text Available The study of nanoparticles as additives for metalworking fluids (MWFs with applications in the metal removal processes, or machining, has received increasing attention due to the possible enhancements on tribological properties. In this study, low-cost and environmentally friendly nanoparticle additives of halloysite clay nanotubes (HNTs were dispersed in metalworking fluids utilized for milling processes. Concentrations of 0.01, 0.05, 0.10 wt. % were incorporated into a mineral oil (MO and a semi-synthetic fluid (SF by ultrasonication. The anti-wear properties of metalworking nanofluids were characterized with a T-05 block-on-ring tribotester at a contact pressure of 0.5 GPa. Surface roughness of worn block materials was obtained with an optical 3D surface measurement system. Results showed that at a concentration of 0.10 wt. % HNTs block mass loss was lowered by 24% for the MO + HNTs nanofluids. For the SF + HNTs, a reduction of 63% and 32% in wear mass loss and coefficient of friction (COF, respectively, were found at the same concentration. The tribological enhancing mechanism for the applied contact pressure was proposed to be due to a reduction of the area of contact and nanoparticle sliding between surfaces with no HNT deposition, evidenced by energy dispersive spectrometry (EDS. Furthermore, surface roughness studies of worn blocks showed smoother surfaces with lower groove density with the addition of nanoparticle additives. The results of this study demonstrate that HNTs can improve the lubricity of metalworking cutting fluids used for machining processes, enhancing tool life and providing better surface finish of products.

  19. Enhanced microwave absorption properties in cobalt–zinc ferrite based nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Poorbafrani, A., E-mail: a.poorbafrani@gmail.com; Kiani, E.

    2016-10-15

    In an attempt to find a solution to the problem of the traditional spinel ferrite used as the microwave absorber, the Co{sub 0.6}Zn{sub 0.4}Fe{sub 2}O{sub 4}–Paraffin nanocomposites were investigated. Cobalt–zinc ferrite powders, synthesized through PVA sol–gel method, were combined with differing concentrations of Paraffin wax. The nanocomposite samples were characterized employing various experimental techniques including X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Alternating Gradient Force Magnetometer (AGFM), and Vector Network Analyzer (VNA). The saturation magnetization and coercivity were enhanced utilizing appropriate stoichiometry, coordinate agent, and sintering temperature required for the preparation of cobalt–zinc ferrite. The complex permittivity and permeability spectra, and Reflection Loss (RL) of Co{sub 0.6}Zn{sub 0.4}Fe{sub 2}O{sub 4}–Paraffin nanocomposites were measured in the frequency range of 1–18 GHz. The microwave absorption properties of nanocomposites indicated that the absorbing composite containing 20 wt% of paraffin manifests the strongest microwave attenuation ability. The composite exhibited the reflection loss less than –10 dB in the whole C-band and 30% of the X-band frequencies. - Highlights: • We enhanced the magnetic properties of cobalt–zinc Ferrite nanocomposites. • The samples showed absorption in the whole C-band and 30% of the X-band frequencies. • We tried to solve the problem of the spinel ferrite utilized as efficient absorber. • We enhanced the microwave reflection loss over extended frequency ranges.

  20. Enhanced electrical transport and thermoelectric properties in Ni doped Cu3SbSe4

    Science.gov (United States)

    Kumar, Aparabal; Dhama, P.; Das, Anish; Sarkar, Kalyan Jyoti; Banerji, P.

    2018-05-01

    In this study, we report the enhanced thermoelectric performance of Cu3SbSe4 by Ni doping at Cu site. Cu3-xNixSbSe4 (x = 0, 0.01, 0.03, 0.05) were prepared by melt growth, ball milling followed by spark plasma sintering. Structural characterization, phase analysis and surface morphology were carried out using X-ray diffraction, field emission scanning electron microscopy and energy dispersive X-ray spectroscopy. Electrical and thermal properties of all the samples were investigated in the temperature range 300 - 650 K. Decrease in electrical resistivity with Ni doping due to increase in carrier concentration with enhanced Seebeck coefficient via increase in density of state near the Fermi level gives a remarkably high power factor. At the same time, thermal conductivity was found to decrease due to increased carrier-phonon scattering and acoustic phonon scattering. Consequently, a remarkable enhancement in the thermoelectric figure of merit (ZT˜ 0.65) of Cu3-xNixSbSe4 was achieved for x = 0.01 sample. Thus, Ni doping is an effective approach to improve the efficiency of Cu3SbSe4.

  1. Novel GQD-PVP-CdS composite with enhanced visible-light-driven photocatalytic properties

    International Nuclear Information System (INIS)

    Fan, Tao; Li, Yinle; Shen, Jianfeng; Ye, Mingxin

    2016-01-01

    Graphical abstract: - Highlights: • GQD-PVP-CdS composite was prepared for the first time through a facile hydrothermal route. • GQD-PVP-CdS demonstrated outstanding photoactivity under visible light illumination. • GQDs and polymeric material are compounded with CdS nanoparticles simultaneously for the first time. • The addition of GQDs plays pivotal roles in the enhancement of the photoactivity. - Abstract: A facile one-step hydrothermal method to synthesize graphene quantum dots (GQDs)-polyvinyl pyrrolidone (PVP)-CdS nanocomposite was reported. The nanocomposite was thoroughly characterized with X-ray diffraction, transmission electron microscopy, scanning electron microscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and ultraviolet–visible spectroscopy. The results confirmed the formation of GQD-PVP-CdS composite with a uniform size (5–10 nm) and a relatively low band gap (E_g = 2.23 eV). Moreover, the as-prepared composite exhibited enhanced photocatalytic activity toward the degradation of organic contaminants, with 92.3% of methyl orange (10 mg/L) removed after 3 hours of visible light illumination. This enhancement in photocatalytic activity was postulated to be attributed to the upconversion property of GQDs and a more efficient charge distribution between GQDs and CdS particles.

  2. Enhanced Photovoltaic Properties of the Solar Cells Based on Cosensitization of CdS and Hydrogenation

    Directory of Open Access Journals (Sweden)

    Hongcai He

    2015-01-01

    Full Text Available The hydrogenated TiO2 porous nanocrystalline film is modified with CdS quantum dots by successive ionic layer adsorption and reaction (SILAR method to prepare the cosensitized TiO2 solar cells by CdS quantum dots and hydrogenation. The structure and topography of the composite photoanode film were confirmed by X-ray diffraction and scanning electron microscopy. With deposited CdS nanoparticles, UV absorption spectra of H:TiO2 photoanode film indicated a considerably enhanced absorption in the visible region. The cosensitized TiO2 solar cell by CdS quantum dots and hydrogenation presents much better photovoltaic properties than either CdS sensitized TiO2 solar cells or hydrogenated TiO2 solar cells, which displays enhanced photovoltaic performance with power conversion efficiency (η of 1.99% (Jsc=6.26 mA cm−2, Voc=0.65 V, and FF = 0.49 under full one-sun illumination. The reason for the enhanced photovoltaic performance of the novel cosensitized solar cell is primarily explained by studying the Nyquist spectrums, IPCE spectra, dark current, and photovoltaic performances.

  3. Chromatographic analysis, anti-proliferative and radical scavenging activity of Pinus wallichina essential oil growing in high altitude areas of Kashmir, India.

    Science.gov (United States)

    Yousuf Dar, Mohd; Shah, Wajaht A; Mubashir, Sofi; Rather, Manzoor A

    2012-10-15

    To evaluate the in vitro anti-proliferative and radical scavenging properties of the essential oil and its fractions and to determine the chemo-type of P. wallichiana essential oil. Pinus wallichiana oil was extracted by hydro-distillation and fractionated by silica gel column chromatography method. The oil and its fractions were analyzed by Gas chromatography, Gas chromatography-mass spectrometry and (13)C NMR. Different concentrations of oil 12.5, 25, 50 and 100μg/ml and single concentration 50μg/ml of its fractions B(1), B(2), A(2), G(2), Uk(13) and I(2) were evaluated for its anti-proliferative activity by in vitro {3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide} assay against human monocyte, lung carcinoma, liver adenocarcinoma, prostate and ovarian carcinoma, while as the radical scavenging activity was evaluated by different in vitro DPPH assays. The analyses indicated the presence of 17 constituents with β-pinene (46.8%) and α-pinene (25.2%) as major constituents. The oil and its fractions showed significant anti-proliferative activity. The radical scavenging activity also showed good results. The oil could be used as a drug to control the diseases like cancer, cirrhosis and arteriosclerosis, caused by reactive oxygen species. Copyright © 2012 Elsevier GmbH. All rights reserved.

  4. Facile synthesis of Cu/tetrapod-like ZnO whisker compounds with enhanced photocatalytic properties

    Science.gov (United States)

    Liu, Hong; Liu, Huarong; Fan, Ximei

    2017-09-01

    Cu/tetrapod-like ZnO whisker (T-ZnOw) compounds were successfully synthesized using N2H4 \\cdot H2O as a reducing agent by a simple reduction method without any insert gas at room temperature. The crystal phase composition and morphology of the as-prepared samples were investigated by XRD, SEM and FESEM tests. The photocatalytic property of the as-prepared samples was detected by the degradation of methyl orange (MO) aqueous solution under UV irradiation. It can be found that Cu nanoparticles (CuNPs) dispersed on the surface of T-ZnOw increased with the increasing of Cu/Zn molar ratios (Cu/Zn MRs), and an octahedral structure of CuNPs was obtained when the sample was prepared with less than and equal to 7.30% Cu/Zn MR, but tended to a spherical or nanorod structure of CuNPs densely arranged on the surface of T-ZnOw, which is prepared by Cu/Zn MRs up to 22.00%. All the compounds exhibited excellent photocatalytic activity in decomposing of MO than T-ZnOw, the photocatalytic property of the samples increased with the increasing of Cu/Zn MRs up to 7.30%, while it decreases when further increasing the Cu/Zn MRs. The Schottky barrier of the Cu/T-ZnOw compound can effectively capture photoinduced electrons from the interface and enhanced the photocatalytic property of T-ZnOw.

  5. Activating "Invisible" Glue: Using Electron Beam for Enhancement of Interfacial Properties of Graphene-Metal Contact.

    Science.gov (United States)

    Kim, Songkil; Russell, Michael; Kulkarni, Dhaval D; Henry, Mathias; Kim, Steve; Naik, Rajesh R; Voevodin, Andrey A; Jang, Seung Soon; Tsukruk, Vladimir V; Fedorov, Andrei G

    2016-01-26

    Interfacial contact of two-dimensional graphene with three-dimensional metal electrodes is crucial to engineering high-performance graphene-based nanodevices with superior performance. Here, we report on the development of a rapid "nanowelding" method for enhancing properties of interface to graphene buried under metal electrodes using a focused electron beam induced deposition (FEBID). High energy electron irradiation activates two-dimensional graphene structure by generation of structural defects at the interface to metal contacts with subsequent strong bonding via FEBID of an atomically thin graphitic interlayer formed by low energy secondary electron-assisted dissociation of entrapped hydrocarbon contaminants. Comprehensive investigation is conducted to demonstrate formation of the FEBID graphitic interlayer and its impact on contact properties of graphene devices achieved via strong electromechanical coupling at graphene-metal interfaces. Reduction of the device electrical resistance by ∼50% at a Dirac point and by ∼30% at the gate voltage far from the Dirac point is obtained with concurrent improvement in thermomechanical reliability of the contact interface. Importantly, the process is rapid and has an excellent insertion potential into a conventional fabrication workflow of graphene-based nanodevices through single-step postprocessing modification of interfacial properties at the buried heterogeneous contact.

  6. Enhanced mechanical properties of hydrothermal carbamated cellulose nanocomposite film reinforced with graphene oxide.

    Science.gov (United States)

    Gan, Sinyee; Zakaria, Sarani; Syed Jaafar, Sharifah Nabihah

    2017-09-15

    Cellulose carbamate (CC) was synthesized via hydrothermal process and mixed with graphene oxide (GO) to form a homogeneous cellulose matrix nanocomposite films. The properties of CC/GO nanocomposite films fabricated using simple solution-mixing method with different GO loadings were studied. Transmission electron microscope analysis showed the exfoliation of self-synthesized GO nanosheets within the CC matrix. X-ray diffraction results confirmed the crystalline structure of CC/GO films as the CC/GO mass ratio increased from 100/0 to 100/4. The mechanical properties of CC/GO film were significantly improved as compared to neat CC film. From thermogravimetric analysis result, the introduction of GO enhanced the thermal stability and carbon yields. The 3D homogeneous porous structures of the CC/GO films were observed under Field emission scanning electron microscope. These improvements in nanocomposite film properties could be confirmed by Fourier transform infrared spectroscopy due to the strong and good interactions between CC and GO. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Mechanism of mechanical property enhancement in nitrogen and titanium implanted 321 stainless steel

    International Nuclear Information System (INIS)

    Xu Ming; Li Liuhe; Liu Youming; Cai Xun; Chen Qiulong; Chu, Paul K.

    2006-01-01

    Ion implantation is a well-known method to modify surface mechanical properties. The improvement of the mechanical properties can usually be attributed to the formation of new strengthening phases, solution strengthening, dislocation strengthening, or grain refinement. However, in many cases, the roles of individual factors are not clear. In this study, we implanted nitrogen and titanium into 321 stainless steel samples to investigate the enhancement mechanism of the mechanical properties. Nano-indentation experiments were conducted to measure the hardness under various loadings. The N and Ti implanted 321 stainless steel samples were found to behave differently in the hardness (GPa) versus depth (nm) diagram. The effects of the radiation damage, solution strengthening, and dispersion strengthening phase were analyzed. Characterization of the modified layers was performed using techniques such as Auger electron spectroscopy (AES) and grazing incidence X-ray diffraction (GIXRD). Transmission electron microscopy (TEM) and X-ray diffraction were also applied to reveal the structure of the untreated 321 stainless steel

  8. Properties enhancement of cassava starch based bioplastics with addition of graphene oxide

    Science.gov (United States)

    Amri, A.; Ekawati, L.; Herman, S.; Yenti, S. R.; Zultiniar; Aziz, Y.; Utami, S. P.; Bahruddin

    2018-04-01

    The properties of cassava starch based bioplastic have been successfully enhanced by additioning of graphene oxide (GO) filler. The composite was synthesized via starch intercalation method using glycerol plasticizer with variation of 5 – 15 % v/v GO filler and mixing time of 30 and 60 minutes. The effects of GO content and the mixing time to the mechanical, water uptake and biodegradation were studied. The synthesis of GO and its integration in the bioplastic composite were also elucidated. The increasing of the GO content and mixing time improved the mechanical properties of composite mainly due to of good homogeneity among the constituents in the composite as indicated by scanning electron microscopy (SEM) and Fourier Transfom Infrared (FTIR) spectroscopy. The bioplastic produced using 15% of GO and 60 minutes mixing time had the highest mechanical properties with tensile strenght of 3,92 Mpa, elongation of 13,22% and modulus young of 29,66 MPa. The water uptake and biodegradation increased as the increase of GO content and decreased as the increase of the mixing time. Graphene oxide is the promissing filler for further development of cassava starch based bioplastics.

  9. Enhancing the Properties of Carbon and Gold Substrates by Surface Modification

    Energy Technology Data Exchange (ETDEWEB)

    Harnisch, Jennifer Anne [Iowa State Univ., Ames, IA (United States)

    2001-01-01

    The properties of both carbon and gold substrates are easily affected by the judicious choice of a surface modification protocol. Several such processes for altering surface composition have been published in literature. The research presented in this thesis primarily focuses on the development of on-column methods to modify carbon stationary phases used in electrochemically modulated liquid chromatography (EMLC). To this end, both porous graphitic carbon (PGC) and glassy carbon (GC) particles have been modified on-column by the electroreduction of arenediazonium salts and the oxidation of arylacetate anions (the Kolbe reaction). Once modified, the carbon stationary phases show enhanced chromatographic performance both in conventional liquid chromatographic columns and EMLC columns. Additionally, one may also exploit the creation of aryl films to by electroreduction of arenediazonium salts in the creation of nanostructured materials. The formation of mercaptobenzene film on the surface of a GC electrode provides a linking platform for the chemisorption of gold nanoparticles. After deposition of nanoparticles, the surface chemistry of the gold can be further altered by self-assembled monolayer (SAM) formation via the chemisorption of a second thiol species. Finally, the properties of gold films can be altered such that they display carbon-like behavior through the formation of benzenehexathiol (BHT) SAMs. BHT chemisorbs to the gold surface in a previously unprecedented planar fashion. Carbon and gold substrates can be chemically altered by several methodologies resulting in new surface properties. The development of modification protocols and their application in the analytical arena is considered herein.

  10. Antiproliferative effects of prenylflavonoids from hops on human colon cancer cell lines

    Czech Academy of Sciences Publication Activity Database

    Hudcová, T.; Bryndová, Jana; Fialová, K.; Fiala, J.; Karabín, M.; Jelínek, L.; Dostalek, P.

    2014-01-01

    Roč. 120, č. 3 (2014), s. 225-230 ISSN 0046-9750 Institutional support: RVO:67985823 Keywords : hop * prenylflavonoids * xanthohumol * isoxanthohumol * antiproliferative * colon cancer Subject RIV: GM - Food Processing Impact factor: 1.240, year: 2014

  11. Polish natural bee honeys are anti-proliferative and anti-metastatic agents in human glioblastoma multiforme U87MG cell line.

    Directory of Open Access Journals (Sweden)

    Justyna Moskwa

    Full Text Available Honey has been used as food and a traditional medicament since ancient times. However, recently many scientists have been concentrating on the anti-oxidant, anti-proliferative, anti-inflammatory and other properties of honey. In this study, we investigated for the first time an anticancer effect of different honeys from Poland on tumor cell line - glioblastoma multiforme U87MG. Anti-proliferative activity of honeys and its interferences with temozolomide were determined by a cytotoxicity test and DNA binding by [H3]-thymidine incorporation. A gelatin zymography was used to conduct an evaluation of metalloproteinases (MMP-2 and MMP-9 expression in U87MG treatment with honey samples. The honeys were previously tested qualitatively (diastase activity, total phenolic content, lead and cadmium content. The data demonstrated that the examined honeys have a potent anti-proliferative effect on U87MG cell line in a time- and dose-dependent manner, being effective at concentrations as low as 0.5% (multifloral light honey - viability 53% after 72 h of incubation. We observed that after 48 h, combining honey with temozolomide showed a significantly higher inhibitory effect than the samples of honey alone. We observed a strong inhibition of MMP-2 and MMP-9 for the tested honeys (from 20 to 56% and from 5 to 58% compared to control, respectively. Our results suggest that Polish honeys have an anti-proliferative and anti-metastatic effect on U87MG cell line. Therefore, natural bee honey can be considered as a promising adjuvant treatment for brain tumors.

  12. Synthesis and antiproliferative activity of a cyclic analog of dolastatin 10.

    Science.gov (United States)

    Poncet, J; Hortala, L; Busquet, M; Guéritte-Voegelein, F; Thoret, S; Pierré, A; Atassi, G; Jouin, P

    1998-10-20

    A cyclic analog of the natural antiproliferative compound dolastatin 10 was synthesized by introducing an ester link between the N- and C-terminal residues which were modified accordingly. The final macrolactonization was performed by using isopropenyl chloroformate and DMAP as reagents. This analog exhibits submicromolar antiproliferative activity against the L1210 and HT29 cell lines and inhibits in vitro tubulin polymerization (IC50, 39 microM).

  13. Effect of gas sparging on flux enhancement and phytochemical properties of clarified pineapple juice by microfiltration

    KAUST Repository

    Laorko, Aporn

    2011-08-01

    Membrane fouling is a major obstacle in the application of microfiltration. Several techniques have been proposed to enhance the permeate flux during microfiltration. Gas sparging is a hydrodynamic method for improving the performance of the membrane process. In this study, a 0.2 μm hollow fiber microfiltration membrane was used to study the effect of cross flow velocity (CFV) and gas injection factor () on the critical and limiting flux during microfiltration of pineapple juice. In addition, the phytochemical properties of clarified juice were investigated. In the absence of gas sparging, the critical and limiting flux increased as the CFV or shear stress number increased. The use of gas sparging led to a remarkable improvement in both the critical and limiting flux but it was more effective at the lower CFV (1.5 m s-1), compared to those at higher CFV (2.0 and 2.5 m s-1). When the gas injection factor was applied at 0.15, 0.25 and 0.35 with a CFV of 1.5 m s -1, the enhancement of 55.6%, 75.5% and 128.2% was achieved for critical flux, while 65.8%, 69.7% and 95.2% was achieved for limiting flux, respectively. The results also indicated that the use of gas sparging was an effective method to reduce reversible fouling and external irreversible fouling rather than internal irreversible fouling. In addition, the CFV and gas sparging did not affect pH, total soluble solids, colour, total phenolic content and the antioxidant property of the clarified juice. The l-ascorbic acid and total vitamin C were significantly decreased when the higher CFV and high gas injection factor were applied. The results also indicated that the use of gas sparging with low CFV was beneficial for flux enhancement while most of the phytochemical properties of the clarified juice was preserved. © 2011 Elsevier B.V. All rights reserved.

  14. The Meaning-Enhancing Properties of Psychedelics and Their Mediator Role in Psychedelic Therapy, Spirituality, and Creativity

    Directory of Open Access Journals (Sweden)

    Ido Hartogsohn

    2018-03-01

    Full Text Available Past research has demonstrated to the ability of psychedelics to enhance suggestibility, and pointed to their ability to amplify perception of meaning. This paper examines the existing evidence for the meaning-enhancing properties of psychedelics, and argues that the tendency of these agents to enhance the perception of significance offers valuable clues to explaining their reported ability to stimulate a variety of therapeutic processes, enhance creativity, and instigate mystical-type experiences. Building upon previous research, which suggested the potential role of psychedelic meaning-enhancement in enhancing placebo response, the paper explores the mechanisms by which the meaning-amplifying properties of psychedelics might also play a role in enhancing creativity, as well as in effecting mystical-type experiences. The wider social and public-health implications of this hypothesis are discussed, and suggestions are made as to the various ways in which scientific understanding of the meaning-enhancing properties of psychedelics might be advanced and utilized.

  15. Enhanced magnetic and ferroelectric properties in scandium doped nano Bi2Fe4O9

    International Nuclear Information System (INIS)

    Dutta, Dimple P.; Sudakar, C.; Mocherla, Pavana S.V.; Mandal, Balaji P.; Jayakumar, Onnatu D.; Tyagi, Avesh K.

    2012-01-01

    In this study we report the synthesis of undoped and Sc 3+ doped Bi 2 Fe 4 O 9 nanoparticles using sonochemical technique. X-ray diffraction reveals that all samples are single phase with no impurities detected. EDS analysis was done to confirm the extent of Sc 3+ doping in the samples. The size and morphology of the nanoparticles have been analyzed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The Bi 2 Fe 4 O 9 nanoparticles show a weak ferromagnetic behavior at room temperature, which is quite different from the linear M–H relationship reported for bulk Bi 2 Fe 4 O 9 . A magnetization of 0.144 μB/f.u. is obtained at 300 K, which is mainly attributed to the uncompensated moments at the disordered particle surface resulting from the reduced coordination of the surface spins, arising due to lattice strain or oxygen deficiency. Addition of Sc 3+ dopant in varying concentrations in these Bi 2 Fe 4 O 9 nanoparticles, improves their magnetic as well as ferroelectric properties. The leakage current is considerably reduced and electric polarization increases significantly in case of Bi 2 Fe 4(1−x) Sc x O 9 (x = 0.1) nanoparticles. Thus it can be inferred that Sc 3+ doped Bi 2 Fe 4 O 9 nanoparticles shows promise as good multiferroic materials. -- Graphical abstract: Undoped and Sc 3+ doped Bi 2 Fe 4 O 9 nanoparticles have been synthesized using sonochemical technique. The bi-functionalities of Sc 3+ doped Bi 2 Fe 4 O 9 nanoparticles have been demonstrated. The Bi 2 Fe 4(1−x) Sc x O 9 (x = 0.1) nanoparticles showed enhanced magnetic and ferroelectric properties with considerably less lossy characteristics compared to the bulk Bi 2 Fe 4 O 9 . Highlights: ► Phase pure Bi 2 Fe 4 O 9 nanostructures synthesized using a facile sonochemical technique. ► Nanoparticles show a weak ferromagnetic order at room temperature. ► Sc 3+ doping in Bi 2 Fe 4 O 9 nanoparticles alters their magnetic and ferroelectric properties. ► A

  16. Anti-proliferative therapy for HIV cure: a compound interest approach.

    Science.gov (United States)

    Reeves, Daniel B; Duke, Elizabeth R; Hughes, Sean M; Prlic, Martin; Hladik, Florian; Schiffer, Joshua T

    2017-06-21

    In the era of antiretroviral therapy (ART), HIV-1 infection is no longer tantamount to early death. Yet the benefits of treatment are available only to those who can access, afford, and tolerate taking daily pills. True cure is challenged by HIV latency, the ability of chromosomally integrated virus to persist within memory CD4 + T cells in a non-replicative state and activate when ART is discontinued. Using a mathematical model of HIV dynamics, we demonstrate that treatment strategies offering modest but continual enhancement of reservoir clearance rates result in faster cure than abrupt, one-time reductions in reservoir size. We frame this concept in terms of compounding interest: small changes in interest rate drastically improve returns over time. On ART, latent cell proliferation rates are orders of magnitude larger than activation and new infection rates. Contingent on subtypes of cells that may make up the reservoir and their respective proliferation rates, our model predicts that coupling clinically available, anti-proliferative therapies with ART could result in functional cure within 2-10 years rather than several decades on ART alone.

  17. Anti-proliferative effects of Bifidobacterium adolescentis SPM0212 extract on human colon cancer cell lines

    International Nuclear Information System (INIS)

    Lee, Do Kyung; Jang, Seok; Kim, Mi Jin; Kim, Jung Hyun; Chung, Myung Jun; Kim, Kyung Jae; Ha, Nam Joo

    2008-01-01

    Lactic acid bacteria (LAB) are beneficial probiotic organisms that contribute to improved nutrition, microbial balance, and immuno-enhancement of the intestinal tract, as well as anti-tumor activity. The aim of the present work was to study the growth inhibition of tumor cells by butanol extract of Bifidobacterium adolescentis isolated from healthy young Koreans. The anti-proliferative activity of B. adolescentis isolates was assessed by XTT assays on three human colon cancer cell lines (Caco-2, HT-29, and SW480). The effects of B. adolescentis SPM0212 butanol extract on tumor necrosis factor-α (TNF-α) and nitric oxide (NO) production were tested using the murine macrophage RAW 264.7 cell line. The butanol extract of B. adolescentis SPM0212 dose-dependently inhibited the growth of Caco-2, HT-29, and SW480 cells by 70%, 30%, and 40%, respectively, at 200 μg/mL. Additionally, the butanol extract of B. adolescentis SPM0212 induced macrophage activation and significantly increased the production of TNF-α and NO, which regulate immune modulation and are cytotoxic to tumor cells. The butanol extract of B. adolescentis SPM0212 increased activity of the host immune system and may improve human health by helping to prevent colon cancer as a biological response modifier

  18. Antiproliferative Activity of Egg Yolk Peptides in Human Colon Cancer Cells.

    Science.gov (United States)

    Yousr, Marwa N; Aloqbi, Akram A; Omar, Ulfat M; Howell, Nazlin K

    2017-01-01

    Egg yolk peptides were successfully prepared from egg yolk protein by-products after lecithin extraction. Defatted egg yolk protein was hydrolyzed with pepsin and pancreatin and purified by gel filtration to produce egg yolk gel filtration fraction (EYGF-33) with antiproliferative activity. The highlight of this study was that the peptide EYGF-33 (1.0 mg/ml) significantly inhibits cell viability of colon cancer cells (Caco-2) with no inhibitory effects on the viability of human colon epithelial normal cells (HCEC) after 48 h. Reduced cell viability can be explained by cell cycle arrest in the S-phase in which DNA replication normally takes place. EYGF-33 significantly enhanced the production of superoxide anions in the mitochondria of Caco-2 cells; this could activate a mitochondrial apoptotic pathway leading to typical Poly Adenosine diphosphate-ribose polymerase (PARP) cleavage as observed in the Western blot result. The induction of apoptotic cell death by EYGF-33 was supported by the externalization of phosphatidylserine (PS). However, further elucidation of the mechanism of EYGF-33-mediated apoptosis would provide further support for its use as a potential therapeutic and chemopreventive agent.

  19. Enhanced UV light detection using wavelength-shifting properties of Silicon nanoparticles

    International Nuclear Information System (INIS)

    Magill, S.; Xie, J.; Nayfeh, M.; Fizari, M.; Malloy, J.; Maximenko, Y.; Yu, H.

    2015-01-01

    Detection of UV photons is becoming increasingly necessary with the use of noble gases and liquids in elementary particle experiments. Cerenkov light in crystals and glasses, scintillation light in neutrino, dark matter, and rare decay experiments all require sensitivity to UV photons. New sensor materials are needed that can directly detect UV photons and/or absorb UV photons and re-emit light in the visible range measurable by existing photosensors. It has been shown that silicon nanoparticles are sensitive to UV light in a wavelength range around ∼ 200 nm. UV light is absorbed and re-emitted at wavelengths in the visible range depending on the size of the nanoparticles. Initial tests of the wavelength-shifting properties of silicon nanoparticles are presented here that indicate by placing a film of nanoparticles in front of a standard visible-wavelength detecting photosensor, the response of the sensor is significantly enhanced at wavelengths < 320 nm

  20. Enhanced photoelectrochemical properties of TiO2 nanorod arrays decorated with CdS nanoparticles

    International Nuclear Information System (INIS)

    Xie, Zheng; Wang, Weipeng; Liu, Can; Li, Zhengcao; Liu, Xiangxuan; Zhang, Zhengjun

    2014-01-01

    TiO 2 nanorod arrays (TiO 2 NRAs) sensitized with CdS nanoparticles were fabricated via successive ion layer adsorption and reaction (SILAR), and TiO 2 NRAs were obtained by oxidizing Ti NRAs obtained through oblique angle deposition. The TiO 2 NRAs decorated with CdS nanoparticles exhibited excellent photoelectrochemical and photocatalytic properties under visible light, and the one decorated with 20 SILAR cycles CdS nanoparticles shows the best performance. This can be attributed to the enhanced separation of electrons and holes by forming heterojunctions of CdS nanoparticles and TiO 2 NRAs. This provides a promising way to fabricate the material for solar energy conversion and wastewater degradation. (paper)

  1. Synthesis of gold nanoflowers using deep eutectic solvent with high surface enhanced Raman scattering properties

    Science.gov (United States)

    Aghakhani Mahyari, Farzaneh; Tohidi, Maryam; Safavi, Afsaneh

    2016-09-01

    A facile, seed-less and one-pot method was developed for synthesis of gold nanoflowers with multiple tips through reduction of HAuCl4 with deep eutectic solvent at room temperature. This solvent is eco-friendly, low-cost, non-toxic and biodegradable and can act as both reducing and shape-controlling agent. In this protocol, highly branched and stable gold nanoflowers were obtained without using any capping agent. The obtained products were characterized by different techniques including, field emission scanning electron microscopy, transmission electron microscopy, x-ray diffraction and UV-vis spectroscopy. The as-prepared gold nanoflowers exhibit efficient surface-enhanced Raman scattering (SERS) properties which can be used as excellent substrates for SERS.

  2. Stress hysteresis and mechanical properties of plasma-enhanced chemical vapor deposited dielectric films

    Science.gov (United States)

    Thurn, Jeremy; Cook, Robert F.; Kamarajugadda, Mallika; Bozeman, Steven P.; Stearns, Laura C.

    2004-02-01

    A comprehensive survey is described of the responses of three plasma-enhanced chemical vapor deposited dielectric film systems to thermal cycling and indentation contact. All three films—silicon oxide, silicon nitride, and silicon oxy-nitride—exhibited significant nonequilibrium permanent changes in film stress on thermal cycling or annealing. The linear relationship between stress and temperature changed after the films were annealed at 300 °C, representing a structural alteration in the film reflecting a change in coefficient of thermal expansion or biaxial modulus. A double-substrate method was used to deduce both thermoelastic properties before and after the anneal of selected films and the results were compared with the modulus deconvoluted from small-scale depth-sensing indentation experiments (nanoindentation). Rutherford backscattering spectrometry and hydrogen forward scattering were used to deduce the composition of the films and it was found that all the films contained significant amounts of hydrogen.

  3. Enhanced thermoelectric property of oxygen deficient nickel doped SnO2 for high temperature application

    Science.gov (United States)

    Paulson, Anju; Sabeer, N. A. Muhammad; Pradyumnan, P. P.

    2018-04-01

    Motivated by the detailed investigation on the thermoelectric performance of oxide materials our work concentrated on the influence of acceptor dopants and defect density in the lattice plane for the enhancement of thermoelectric power. The series of Sn1‑x Nix O2 (0.01 ≤ x ≤ 0.05) compositions were prepared by solid state reaction mechanism and found that 3 atomic percentage Ni doped SnO2 can be considered as a good candidate due to its promising electrical and transport properties. Defect lattices were introduced in the sample and the deviation from oxygen stochiometry was ensured using photoluminescence measurement. High power factor was obtained for the 3 atomic percentage nickel doped SnO2 due to the effective number of charge carrier concentration and the depletion of oxygen rich layers. Defect centered and acceptor doped SnO2 lattice opens a new door for energy harvesting at higher temperatures.

  4. Enhanced Properties of Porous GaN Prepared by UV Assisted Electrochemical Etching

    International Nuclear Information System (INIS)

    Ainorkhilah Mahmood; Ainorkhilah Mahmood; Siang, C.L.

    2011-01-01

    The structural and optical properties of porous GaN films on sapphire (0001) prepared by UV assisted electrochemical etching were reported in this study. SEM micrographs indicated that the shapes of the pores for both porous samples are nearly hexagonal. XRD revealed that the broadening in spectrum is due to the small size crystallites. As compared to the as grown GaN films, porous layers exhibit a substantial photoluminescence (PL) intensity enhancement with red-shifted band-edge PL peaks associated with the relaxation of compressive stress. The shift of E2(high) to the lower frequency in Raman spectra of the porous GaN films further confirms such a stress relaxation. (author)

  5. Retracted-Enhanced X-Ray Absorption Property of Gold-Doped Single Wall Carbon Nanotube

    Directory of Open Access Journals (Sweden)

    Alimin Alimin

    2015-11-01

    Full Text Available Enhanced X-ray absorption property of single wall carbon nanotube (SWCNT through gold (Au doping (Au@SWCNT has been studied. Mass attenuation coefficient of SWCNT increased 5.2-fold after Au doping treatment. The use of ethanol in the liquid phase adsorption could produce Au nanoparticles as confirmed by the X-ray Diffraction (XRD patterns. The possibility of gold nanoparticles encapsulated in the internal tube space of SWCNT was observed by transmission electron microscope technique. A significant decrease of nitrogen uptakes and upshifts of Radial Breathing Mode (RBM of Au@SWCNT specimen suggest that the nanoparticles might be encapsulated in the internal tube spaces of the nanotube. In addition, a decrease intensity of XRD pattern of Au@SWCNT at around 2θ ≈ 2.6° supports the suggestion that Au nanoparticles are really encapsulated into SWCNT.

  6. Enhanced photovoltaic properties of perovskite solar cells by TiO2 homogeneous hybrid structure.

    Science.gov (United States)

    Su, Pengyu; Fu, Wuyou; Yao, Huizhen; Liu, Li; Ding, Dong; Feng, Fei; Feng, Shuang; Xue, Yebin; Liu, Xizhe; Yang, Haibin

    2017-10-01

    In this paper, we fabricated a TiO 2 homogeneous hybrid structure for application in perovskite solar cells (PSCs) under ambient conditions. Under the standard air mass 1.5 global (AM 1.5G) illumination, PSCs based on homogeneous hybrid structure present a maximum power conversion efficiency of 5.39% which is higher than that of pure TiO 2 nanosheets. The enhanced properties can be explained by the better contact of TiO 2 nanosheets/nanoparticles with CH 3 NH 3 PbI 3 and fewer pinholes in electron transport materials. The advent of such unique structure opens up new avenues for the future development of high-efficiency photovoltaic cells.

  7. Plasmonic properties and enhanced fluorescence of gold and dye-doped silica nanoparticle aggregates

    Science.gov (United States)

    Green, Nathaniel Scott

    The development of metal-enhanced fluorescence has prompted a great interest in augmenting the photophysical properties of fluorescent molecules with noble metal nanostructures. Our research efforts, outlined in this dissertation, focus on augmenting properties of fluorophores by conjugation with gold nanostructures. The project goals are split into two separate efforts; the enhancement in brightness of fluorophores and long distance non-radiative energy transfer between fluorophores. We believe that interacting dye-doped silica nanoparticles with gold nanoparticles can facilitate both of these phenomena. Our primary research interest is focused on optimizing brightness, as this goal should open a path to studying the second goal of non-radiative energy transfer. The two major challenges to this are constructing suitable nanomaterials and functionalizing them to promote plasmonically active complexes. The synthesis of dye-doped layered silica nanoparticles allows for control over the discrete location of the dye and a substrate that can be surface functionalized. Controlling the exact location of the dye is important to create a silica spacer, which promotes productive interactions with metal nanostructures. Furthermore, the synthesis of silica nanoparticles allows for various fluorophores to be studied in similar environments (removing solvent and other chemo-sensitive issues). Functionalizing the surface of silica nanoparticles allows control over the degree of silica and gold nanoparticle aggregation in solution. Heteroaggregation in solution is useful for producing well-aggregated clusters of many gold around a single silica nanoparticle. The dye-doped surface functionalized silica nanoparticles can than be mixed efficiently with gold nanomaterials. Aggregating multiple gold nanospheres around a single dye-doped silica nanoparticle can dramatically increase the fluorescent brightness of the sample via metal-enhanced fluorescence due to increase plasmonic

  8. Antibacterial, Antiproliferative, and Immunomodulatory Activity of Silver Nanoparticles Synthesized with Fucans from the Alga Dictyota mertensii

    Directory of Open Access Journals (Sweden)

    Marília Medeiros Fernandes-Negreiros

    2017-12-01

    Full Text Available In this study, we aimed to synthesize silver nanoparticles containing fucans from Dictyota mertensii (Martius Kützing using an environmentally friendly method and to characterize their structure as well as antiproliferative, immunomodulatory, and antibacterial effects. Fucan-coated silver nanoparticles (FN were characterized by Fourier-transform infrared analysis, dynamic light scattering, zeta potential, atomic force microscopy, energy dispersive X-ray spectroscopy, and inductively coupled plasma emission spectrometry. They were evaluated for their effect on cell viability, minimum inhibitory bactericidal concentration, and release of nitric oxide and cytokines. The FN were successfully synthesized using an environmentally friendly method. They were size-stable for 16 months, of a spherical shape, negative charge (−19.1 mV, and an average size of 103.3 ± 43 nm. They were able to inhibit the proliferation of the melanoma tumor cell line B16F10 (60%. In addition, they had immunomodulatory properties: they caused an up to 7000-fold increase in the release of nitric oxide and cytokines (IL-10; IL-6 and TNF-α up to 7000 times. In addition, the FN showed inhibitory effect on Gram-positive and -negative bacteria, with MIC values of 50 µg/mL. Overall, the data showed that FN are nanoparticles with the potential to be used as antitumor, immunomodulatory, and antibacterial agents.

  9. A Novel Hemagglutinin with Antiproliferative Activity against Tumor Cells from the Hallucinogenic Mushroom Boletus speciosus

    Directory of Open Access Journals (Sweden)

    Jian Sun

    2014-01-01

    Full Text Available Little was known about bioactive compounds from the hallucinogenic mushroom Boletus speciosus. In the present study, a hemagglutinin (BSH, B. speciosus hemagglutinin was isolated from its fruiting bodies and enzymatic properties were also tested. The chromatographic procedure utilized comprised anion exchange chromatography on Q-Sepharose, cation exchange chromatography on CM-Cellulose, cation exchange chromatography on SP-Sepharose, and gel filtration by FPLC on Superdex 75. The hemagglutinin was a homodimer which was estimated to be approximately 31 kDa in size. The activity of BSH was stable up to 60°C, while there was a precipitous drop in activity when the temperature was elevated to 70°C. BSH retained 25% hemagglutinating activity when exposed to 100 mM NaOH and 25 mM HCl. The activity was potently inhibited by 1.25 mM Hg2+ and slightly inhibited by Fe2+, Ca2+, and Pb2+. None of the sugars tested showed inhibition towards BSH. Its hemagglutinating activity towards human erythrocytes type A, type B, and type AB was higher than type O. The hemagglutinin showed antiproliferative activity towards hepatoma Hep G2 cells and mouse lymphocytic leukemia cells (L1210 in vitro, with IC50 of 4.7 μM and 7.0 μM, respectively. It also exhibited HIV-1 reverse transcriptase inhibitory activity with an IC50 of 7.1 μM.

  10. A novel hemagglutinin with antiproliferative activity against tumor cells from the hallucinogenic mushroom Boletus speciosus.

    Science.gov (United States)

    Sun, Jian; Ng, Tzi-Bun; Wang, Hexiang; Zhang, Guoqing

    2014-01-01

    Little was known about bioactive compounds from the hallucinogenic mushroom Boletus speciosus. In the present study, a hemagglutinin (BSH, B. speciosus hemagglutinin) was isolated from its fruiting bodies and enzymatic properties were also tested. The chromatographic procedure utilized comprised anion exchange chromatography on Q-Sepharose, cation exchange chromatography on CM-Cellulose, cation exchange chromatography on SP-Sepharose, and gel filtration by FPLC on Superdex 75. The hemagglutinin was a homodimer which was estimated to be approximately 31 kDa in size. The activity of BSH was stable up to 60°C, while there was a precipitous drop in activity when the temperature was elevated to 70°C. BSH retained 25% hemagglutinating activity when exposed to 100 mM NaOH and 25 mM HCl. The activity was potently inhibited by 1.25 mM Hg(2+) and slightly inhibited by Fe(2+), Ca(2+), and Pb(2+). None of the sugars tested showed inhibition towards BSH. Its hemagglutinating activity towards human erythrocytes type A, type B, and type AB was higher than type O. The hemagglutinin showed antiproliferative activity towards hepatoma Hep G2 cells and mouse lymphocytic leukemia cells (L1210) in vitro, with IC50 of 4.7 μ M and 7.0 μ M, respectively. It also exhibited HIV-1 reverse transcriptase inhibitory activity with an IC50 of 7.1 μ M.

  11. Pyridine-substituted thiazolylphenol derivatives: Synthesis, modeling studies, aromatase inhibition, and antiproliferative activity evaluation.

    Science.gov (United States)

    Ertas, Merve; Sahin, Zafer; Berk, Barkin; Yurttas, Leyla; Biltekin, Sevde N; Demirayak, Seref

    2018-04-01

    Drugs used in breast cancer treatments target the suppression of estrogen biosynthesis. During this suppression, the main goal is to inhibit the aromatase enzyme that is responsible for the cyclization and structuring of estrogens either with steroid or non-steroidal-type inhibitors. Non-steroidal derivatives generally have a planar aromatic structure attached to the triazole ring system in their structures, which inhibits hydroxylation reactions during aromatization by coordinating the heme group. Bioisosteric replacement of the triazole ring system and development of aromatic/cyclic structures of the side chain can increase the selectivity for aromatase enzyme inhibition. In this study, pyridine-substituted thiazolylphenol derivatives, which are non-steroidal triazole bioisosteres, were synthesized using the Hantzsch method, and physical analysis and structural determination studies were performed. The IC 50 values of the compounds were determined by a fluorescence-based aromatase inhibition assay. Then, their antiproliferative activities on the MCF7 and HEK 293 cell lines were evaluated with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Furthermore, the crystal structure of human placental aromatase was subjected to a series of docking experiments to identify the possible interactions between the most active structure and the active site. Lastly, an in silico technique was performed to analyze and predict the drug-likeness, molecular and ADME properties of the synthesized molecules. © 2018 Deutsche Pharmazeutische Gesellschaft.

  12. Implantation and growth of dendritic gold nanostructures on graphene derivatives: electrical property tailoring and Raman enhancement.

    Science.gov (United States)

    Jasuja, Kabeer; Berry, Vikas

    2009-08-25

    Interfacing electron-rich metal nanoparticles with graphene derivatives can sensitively regulate the properties of the resultant hybrid with potential applications in metal-doped graphene field-effect transistors (FETs), surface-enhanced Raman spectroscopy, and catalysis. Here, we show that by controlling the rate of diffusion and catalytic reduction of gold ions on graphene oxide (GO), dendritic "snowflake-shaped" gold nanostructures (SFGNs) can be templated on graphene. The structural features of the SFGNs and their interfacing mechanism with GO were characterized by microscopic analysis and Raman-scattering. We demonstrate that (a) SFGNs grow on GO-surface via diffusion limited aggregation; (b) SFGN's morphology (dendritic to globular), size (diameter of 150-500 nm and a height of 45-55 nm), coverage density, and dispersion stability can be controlled by regulating the chemiophysical forces; (c) SFGNs enhance the Raman signal by 2.5 folds; and (d) SFGNs act as antireduction resist during GO-SFGN's chemical reduction. Further, the SFGNs interfacing with graphene reduces the apparent band gap (from 320 to 173 meV) and the Schottky barrier height (from 126 to 56 meV) of the corresponding FET.

  13. Enhanced photocatalytic activity of C@ZnO core-shell nanostructures and its photoluminescence property

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Tao; Yu, Shanwen; Fang, Xiaoxin; Huang, Honghong; Li, Lun [School of Materials and Chemical Engineering, Hubei University of Technology, Wuhan (China); Wang, Xiuyuan [College of Plant Science and Technology, Huazhong Agricultural University, Wuhan (China); Wang, Huihu, E-mail: wanghuihu@mail.hbut.edu.cn [School of Materials and Chemical Engineering, Hubei University of Technology, Wuhan (China); Hubei Provincial Key Laboratory of Green Materials for Light Industry, Hubei University of Technology, Wuhan (China)

    2016-12-15

    Highlights: • C@ZnO nanostructures were synthesized by a facile hydrothermal carbonization method. • Glucose content has a great influence on the microstructure of C@ZnO nanostructures. • An ultrathin amorphous carbon layer enhances the adsorption capacity of C@ZnO. • C@ZnO nanostructures exhibit the improved photocatalytic activity and stability. - Abstract: An ultrathin layer of amorphous carbon coated C@ZnO core-shell nanostructures were synthesized via a facile hydrothermal carbonization process using glucose as precursor in this work. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and diffuse reflectance UV–vis spectroscopy (DRS) were used for the characterization of as-prepared samples. Photoluminescence (PL) properties of C@ZnO samples were investigated using PL spectroscopy. The microstructure analysis results show that the glucose content has a great influence on the size, morphology, crystallinity and surface chemical states of C@ZnO nanostructures. Moreover, the as-prepared C@ZnO core-shell nanostructures exhibit the enhanced photocatalytic activity and good photostability for methyl orange dye degradation due to its high adsorption ability and its improved optical characteristics.

  14. Enhancement of mechanical and electrical properties of continuous-fiber-reinforced epoxy composites with stacked graphene.

    Science.gov (United States)

    Naveh, Naum; Shepelev, Olga; Kenig, Samuel

    2017-01-01

    Impregnation of expandable graphite (EG) after thermal treatment with an epoxy resin containing surface-active agents (SAAs) enhanced the intercalation of epoxy monomer between EG layers and led to further exfoliation of the graphite, resulting in stacks of few graphene layers, so-called "stacked" graphene (SG). This process enabled electrical conductivity of cured epoxy/SG composites at lower percolation thresholds, and improved thermo-mechanical properties were measured with either Kevlar, carbon or glass-fiber-reinforced composites. Several compositions with SAA-modified SG led to higher dynamic moduli especially at high temperatures, reflecting the better wetting ability of the modified nanoparticles. The hydrophilic/hydrophobic nature of the SAA dictates the surface energy balance. More hydrophilic SAAs promoted localization of the SG at the Kevlar/epoxy interface, and morphology seems to be driven by thermodynamics, rather than the kinetic effect of viscosity. This effect was less obvious with carbon or glass fibers, due to the lower surface energy of the carbon fibers or some incompatibility with the glass-fiber sizing. Proper choice of the surfactant and fine-tuning of the crosslink density at the interphase may provide further enhancements in thermo-mechanical behavior.

  15. Enhancement of mechanical and electrical properties of continuous-fiber-reinforced epoxy composites with stacked graphene

    Directory of Open Access Journals (Sweden)

    Naum Naveh

    2017-09-01

    Full Text Available Impregnation of expandable graphite (EG after thermal treatment with an epoxy resin containing surface-active agents (SAAs enhanced the intercalation of epoxy monomer between EG layers and led to further exfoliation of the graphite, resulting in stacks of few graphene layers, so-called “stacked” graphene (SG. This process enabled electrical conductivity of cured epoxy/SG composites at lower percolation thresholds, and improved thermo-mechanical properties were measured with either Kevlar, carbon or glass-fiber-reinforced composites. Several compositions with SAA-modified SG led to higher dynamic moduli especially at high temperatures, reflecting the better wetting ability of the modified nanoparticles. The hydrophilic/hydrophobic nature of the SAA dictates the surface energy balance. More hydrophilic SAAs promoted localization of the SG at the Kevlar/epoxy interface, and morphology seems to be driven by thermodynamics, rather than the kinetic effect of viscosity. This effect was less obvious with carbon or glass fibers, due to the lower surface energy of the carbon fibers or some incompatibility with the glass-fiber sizing. Proper choice of the surfactant and fine-tuning of the crosslink density at the interphase may provide further enhancements in thermo-mechanical behavior.

  16. Properties and uses of storage for enhancing the grid penetration of very large photovoltaic systems

    International Nuclear Information System (INIS)

    Solomon, A.A.; Faiman, D.; Meron, G.

    2010-01-01

    In this third paper, which studies the hourly generation data for the year 2006 from the Israel Electric Corporation, with a view to incorporating very large photovoltaic (PV) power plants, we address the question: What properties should storage have in order to enhance the grid penetration of large PV systems in an efficient and substantial manner? We first impose the constraint that no PV energy losses are permitted other than those due to storage inefficiency. This constraint leads to powerful linkages between the energy capacity and power capacity of storage, and PV system size, and their combined effect on grid penetration. Various strategies are then examined for enhancing grid penetration, based upon this newfound knowledge. Specific strategies examined include PV energy dumping and baseload rescheduling both on a seasonal basis and shorter time periods. We found, inter alia, that at high grid flexibilities (in the range ff=0.8-1), PV grid penetration levels could be possible in the range 60-90% of annual requirements. Moreover, with appropriately designed storage and accurate forecasting, a future grid could be operated at ff=1.

  17. Chitosan nanocomposite films: enhanced electrical conductivity, thermal stability, and mechanical properties.

    Science.gov (United States)

    Marroquin, Jason B; Rhee, K Y; Park, S J

    2013-02-15

    A novel, high-performance Fe(3)O(4)/MWNT/Chitosan nanocomposite has been prepared by a simple solution evaporation method. A significant synergistic effect of Fe(3)O(4) and MWNT provided enhanced electrical conductivity, mechanical properties, and thermal stability on the nanocomposites. A 5% (wt) loading of Fe(3)O(4)/MWNT in the nanocomposite increased conductivity from 5.34×10(-5) S/m to 1.49×10(-2) S/m compared to 5% (wt) MWNT loadings. The Fe(3)O(4)/MWNT/Chitosan films also exhibited increases in tensile strength and modulus of 70% and 155%, respectively. The integral procedure decomposition temperature (IPDT) was enhanced from 501 °C to 568 °C. These effects resulted from a number of factors: generation of a greater number of conductive channels through interactions between MWNT and Fe(3)O(4) surfaces, a higher relative crystallinity, the antiplasticizing effects of Fe(3)O(4), a restricted mobility and hindrance of depolymerization of the Chitosan chain segments, as well as uniform distribution, improved dispersion, and strong interfacial adhesion between the MWNT and Chitosan matrix. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Enhanced Microbial, Functional and Sensory Properties of Herbal Yogurt Fermented with Korean Traditional Plant Extracts.

    Science.gov (United States)

    Joung, Jae Yeon; Lee, Ji Young; Ha, Young Sik; Shin, Yong Kook; Kim, Younghoon; Kim, Sae Hun; Oh, Nam Su

    2016-01-01

    This study evaluated the effects of two Korean traditional plant extracts (Diospyros kaki THUNB. leaf; DK, and Nelumbo nucifera leaf; NN) on the fermentation, functional and sensory properties of herbal yogurts. Compared to control fermentation, all plant extracts increased acidification rate and reduced the time to complete fermentation (pH 4.5). Supplementation of plant extracts and storage time were found to influence the characteristics of the yogurts, contributing to increased viability of starter culture and phenolic compounds. In particular, the increase in the counts of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus was highest (2.95 and 1.14 Log CFU/mL respectively) in DK yogurt. Furthermore, supplementation of the plant extracts significantly influenced to increase the antioxidant activity and water holding capacity and to produce volatile compounds. The higher antioxidant activity and water holding capacity were observed in NN yogurt than DK yogurt. Moreover, all of the sensory characteristics were altered by the addition of plant extracts. Addition of plant extracts increased the scores related to flavor, taste, and texture from plain yogurt without a plant extract, as a result of volatile compounds analysis. Thus, the overall preference was increased by plant extracts. Consequently, supplementation of DK and NN extracts in yogurt enhanced the antioxidant activity and physical property, moreover increased the acceptability of yogurt. These findings demonstrate the possibility of using plant extracts as a functional ingredient in the manufacture of herbal yogurt.

  19. Pyrene-Phosphonate Conjugate: Aggregation-Induced Enhanced Emission, and Selective Fe3+ Ions Sensing Properties

    Directory of Open Access Journals (Sweden)

    Sachin D. Padghan

    2017-08-01

    Full Text Available A new pyrene-phosphonate colorimetric receptor 1 has been designed and synthesized in a one-step process via amide bond formation between pyrene butyric acid chloride and phosphonate-appended aniline. The pyrene-phosphonate receptor 1 showed aggregation-induced enhanced emission (AIEE properties in water/acetonitrile (ACN solutions. Dynamic light scattering (DLS characterization revealed that the aggregates of receptor 1 at 80% water fraction have an average size of ≈142 nm. Field emission scanning electron microscopy (FE-SEM analysis confirmed the formation of spherical aggregates upon solvent evaporation. The sensing properties of receptor 1 were investigated by UV-vis, fluorescence emission spectroscopy, and other optical methods. Among the tested metal ions, receptor 1 is capable of recognizing the Fe3+ ion selectively. The changes in spectral measurements were explained on the basis of complex formation. The composition of receptor 1 and Fe3+ ions was determined by using Job’s plot and found to be 1:1. The receptor 1–Fe3+ complex showed a reversible UV-vis response in the presence of EDTA.

  20. Development of Chitosan Scaffolds with Enhanced Mechanical Properties for Intestinal Tissue Engineering Applications.

    Science.gov (United States)

    Zakhem, Elie; Bitar, Khalil N

    2015-10-13

    Massive resections of segments of the gastrointestinal (GI) tract lead to intestinal discontinuity. Functional tubular replacements are needed. Different scaffolds were designed for intestinal tissue engineering application. However, none of the studies have evaluated the mechanical properties of the scaffolds. We have previously shown the biocompatibility of chitosan as a natural material in intestinal tissue engineering. Our scaffolds demonstrated weak mechanical properties. In this study, we enhanced the mechanical strength of the scaffolds with the use of chitosan fibers. Chitosan fibers were circumferentially-aligned around the tubular chitosan scaffolds either from the luminal side or from the outer side or both. Tensile strength, tensile strain, and Young's modulus were significantly increased in the scaffolds with fibers when compared with scaffolds without fibers. Burst pressure was also increased. The biocompatibility of the scaffolds was maintained as demonstrated by the adhesion of smooth muscle cells around the different kinds of scaffolds. The chitosan scaffolds with fibers provided a better candidate for intestinal tissue engineering. The novelty of this study was in the design of the fibers in a specific alignment and their incorporation within the scaffolds.

  1. Enhanced mechanical and thermal properties of poly (vinyl alcohol)/corn starch blends by nanoclay intercalation.

    Science.gov (United States)

    Tian, Huafeng; Wang, Kai; Liu, Di; Yan, Jiaan; Xiang, Aimin; Rajulu, A Varada

    2017-08-01

    Poly (vinyl alcohol) (PVA)/corn starch blend films with enhanced properties were fabricated by melt processing and montmorillonite (MMT) reinforcing. It was revealed that strong hydrogen bonding occurred between the abundant OH groups of the matrix and polar SiOSi and OH groups of MMT. The highly exfoliated MMT nanolayers were randomly dispersed in the matrix containing MMT lower than 10wt%, whereas the intercalated structure was predominant with MMT content higher than 10wt%. With the increase of MMT, the glass transition temperature as well as equilibrium torque increased. The water sorption decreased and water resistant properties were improved with the incorporation of MMT due to the restricted swelling of the matrix by MMT nanolayers. Significant improvement in strength and flexibility were observed due to the fine dispersion of the MMT layers and the strong interaction between MMT and the matrix. The thermal stability was also improved. The MMT nanolayers could act as the heat and mass transport barriers and retard the thermal decomposition of the composites. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Electrical transport properties of graphene nanowalls grown at low temperature using plasma enhanced chemical vapor deposition

    Science.gov (United States)

    Zhao, Rong; Ahktar, Meysam; Alruqi, Adel; Dharmasena, Ruchira; Jasinski, Jacek B.; Thantirige, Rukshan M.; Sumanasekera, Gamini U.

    2017-05-01

    In this work, we report the electrical transport properties of uniform and vertically oriented graphene (graphene nanowalls) directly synthesized on multiple substrates including glass, Si/SiO2 wafers, and copper foils using radio-frequency plasma enhanced chemical vapor deposition (PECVD) with methane (CH4) as the precursor at relatively low temperatures. The temperature for optimum growth was established with the aid of transmission electron microscopy, scanning electron microscopy, and Raman spectroscopy. This approach offers means for low-cost graphene nanowalls growth on an arbitrary substrate with the added advantage of transfer-free device fabrication. The temperature dependence of the electrical transport properties (resistivity and thermopower) were studied in the temperature range, 30-300 K and analyzed with a combination of 2D-variable range hopping (VRH) and thermally activated (TA) conduction mechanisms. An anomalous temperature dependence of the thermopower was observed for all the samples and explained with a combination of a diffusion term having a linear temperature dependence plus a term with an inverse temperature dependence.

  3. Largely enhanced thermal and mechanical properties of polymer nanocomposites via incorporating C60@graphene nanocarbon hybrid

    International Nuclear Information System (INIS)

    Song, Ping’an; Liu, Lina; Yu, Youming; Huang, Guobo; Guo, Qipeng

    2013-01-01

    Although considerable progress has been achieved to create advanced polymer nanocomposites using nanocarbons including fullerene (C 60 ) and graphene, it remains a major challenge to effectively disperse them in a polymer matrix and to fully exert their extraordinary properties. Here we report a novel approach to fabricate the C 60 @graphene nanocarbon hybrid (C 60 : ∼47.9 wt%, graphene: ∼35.1%) via three-step reactions. The presence of C 60 on a graphene sheet surface can effectively prevent the aggregation of the latter which in turn helps the dispersion of the former in a polymer matrix during melt-processing. C 60 @graphene is found to be uniformly dispersed in a polypropylene (PP) matrix. Compared with pristine C 60 or graphene, C 60 @graphene further improves the thermal stability and mechanical properties of PP. The incorporation of 2.0 wt% C 60 @graphene (relative to PP) can remarkably increase the initial degradation temperature by around 59 ° C and simultaneously enhance the tensile strength and Young’s modulus by 67% and 76%, respectively, all of which are higher than those of corresponding PP/C 60 (graphene) nanocomposites. These significant performance improvements are mainly due to the free-radical-trapping effect of C 60 , and the thermal barrier and reinforcing effects of graphene nanosheets as well as the effective stress load transfer. This work provides a new methodology to design multifunctional nanohybrids for creating advanced materials. (paper)

  4. Ambient redox synthesis of vanadium-doped manganese dioxide nanoparticles and their enhanced zinc storage properties

    Science.gov (United States)

    Alfaruqi, Muhammad Hilmy; Islam, Saiful; Mathew, Vinod; Song, Jinju; Kim, Sungjin; Tung, Duong Pham; Jo, Jeonggeun; Kim, Seokhun; Baboo, Joseph Paul; Xiu, Zhiliang; Kim, Jaekook

    2017-05-01

    In this work, we demonstrate the first use of a V-doped MnO2 nanoparticle electrode for zinc-ion battery (ZIB) applications. The V-doped MnO2 was prepared via a simple redox reaction and the X-ray diffraction studies confirmed the formation of pure MnO2, accompanied by an anisotropic expansion of MnO2 lattice, suggesting the incorporation of V-ions into the MnO2 framework. V doping of MnO2 not only increased the specific surface area but also improved the electronic conductivity. When Zn-storage properties were tested, the V-doped MnO2 electrode registered a higher discharge capacity of 266 mAh g-1 compared to 213 mAh g-1 for the pure MnO2 electrode. On prolonged cycling, the doped electrode retained 31% higher capacity than that of the bare MnO2 electrode and thereby demonstrated superior cycling performance. This study may pave the way towards understanding the enhancement of the energy storage properties via doping in electrodes of aqueous ZIB applications and also furthers the efforts for the practical realization of a potential eco-friendly battery system.

  5. Enhanced Microbial, Functional and Sensory Properties of Herbal Yogurt Fermented with Korean Traditional Plant Extracts

    Science.gov (United States)

    Joung, Jae Yeon; Lee, Ji Young; Ha, Young Sik; Shin, Yong Kook; Kim, Younghoon; Kim, Sae Hun; Oh, Nam Su

    2016-01-01

    This study evaluated the effects of two Korean traditional plant extracts (Diospyros kaki THUNB. leaf; DK, and Nelumbo nucifera leaf; NN) on the fermentation, functional and sensory properties of herbal yogurts. Compared to control fermentation, all plant extracts increased acidification rate and reduced the time to complete fermentation (pH 4.5). Supplementation of plant extracts and storage time were found to influence the characteristics of the yogurts, contributing to increased viability of starter culture and phenolic compounds. In particular, the increase in the counts of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus was highest (2.95 and 1.14 Log CFU/mL respectively) in DK yogurt. Furthermore, supplementation of the plant extracts significantly influenced to increase the antioxidant activity and water holding capacity and to produce volatile compounds. The higher antioxidant activity and water holding capacity were observed in NN yogurt than DK yogurt. Moreover, all of the sensory characteristics were altered by the addition of plant extracts. Addition of plant extracts increased the scores related to flavor, taste, and texture from plain yogurt without a plant extract, as a result of volatile compounds analysis. Thus, the overall preference was increased by plant extracts. Consequently, supplementation of DK and NN extracts in yogurt enhanced the antioxidant activity and physical property, moreover increased the acceptability of yogurt. These findings demonstrate the possibility of using plant extracts as a functional ingredient in the manufacture of herbal yogurt. PMID:27499669

  6. Graphene immobilized enzyme/polyethersulfone mixed matrix membrane: Enhanced antibacterial, permeable and mechanical properties

    International Nuclear Information System (INIS)

    Duan, Linlin; Wang, Yuanming; Zhang, Yatao; Liu, Jindun

    2015-01-01

    Graphical abstract: - Highlights: • Lysozyme was immobilized on the surface of graphene oxide (GO) and reduced GO (RGO). • The novel hybrid membranes based on lysozyme and graphene were fabricated firstly. • These membranes showed good antibacterial and mechanical performance. - Abstract: Enzyme immobilization has been developed to address lots of issues of free enzyme, such as instability, low activity and difficult to retain. In this study, graphene was used as an ideal carrier for lysozyme immobilization, including graphene oxide (GO) immobilized lysozyme (GO-Ly) and chemically reduced graphene oxide (CRGO) immobilized lysozyme (CRGO-Ly). Herein, lysozyme as a bio-antibacterial agent has excellent antibacterial performance and the products of its catalysis are safety and nontoxic. Then the immobilized lysozyme materials were blended into polyethersulfone (PES) casting solution to prepare PES ultrafiltration membrane via phase inversion method. GO and CRGO were characterized by Fourier transform infrared spectroscopy (FTIR), Ultraviolet–visible spectrum (UV), X-ray diffraction (XRD), and transmission electron microscopy (TEM) and the immobilized lysozyme composites were observed by fluorescent microscopy. The results revealed that GO and CRGO were successfully synthesized and lysozyme was immobilized on their surfaces. The morphology, hydrophilicity, mechanical properties, separation properties and antibacterial activity of the hybrid membranes were characterized in detail. The hydrophilicity, water flux and mechanical strength of the hybrid membranes were significantly enhanced after adding the immobilized lysozyme. In the antibacterial experiment, the hybrid membranes exhibited an effective antibacterial performance against Escherichia coli (E. coli).

  7. Enhancing the antimony sorption properties of nano titania-chitosan beads using epichlorohydrin as the crosslinker.

    Science.gov (United States)

    Nishad, Padala Abdul; Bhaskarapillai, Anupkumar; Velmurugan, Sankaralingam

    2017-07-15

    Antimony is classified as a pollutant of priority importance by USEPA. We have earlier reported the synthesis of nano-titania impregnated epichlorohydrin crosslinked chitosan (TA-Cts-Epi) beads, in a format suitable for large scale applications with high sorption capacity for antimony. To understand the sorption mechanism, and to fine tune the bead composition, the effect of crosslinking density on the swelling and sorption properties of the beads was investigated in detail. Epichlorohydrin effected significant changes in physical and sorption properties of the beads. The antimony sorption capacity of the TA-Cts-Epi beads prepared by crosslinking 0.3g non-crosslinked titania-chitosan beads (TA-Cts-NCL) with 6.4mmol epichlorohydrin was 493μmol/g, while those crosslinked with 0.64mmol showed a capacity of 133μmol/g. Whereas, TA-Cts-NCL beads showed a capacity of 75μmol/g. The increase in uptake capacity with increase in crosslinking demonstrated the active involvement of the epichlorohydrin moieties in antimony binding leading to enhanced sorption. Apart from altering the stability, swelling behaviour and sorption kinetics of the beads, crosslinking significantly increased the uptake of the anionic species via electrostatic interactions. Epichlorohydrin crosslinked chitosan beads prepared without TiO 2 also showed similar behaviour. The results demonstrated the involvement of chitosan, TiO 2 and epichlorohydrin in sorption. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Enhanced photoelectrochemical properties of copper-assisted catalyzed etching black silicon by electrodepositing cobalt

    Science.gov (United States)

    Cai, Weidong; Xiong, Haiying; Su, Xiaodong; Zhou, Hao; Shen, Mingrong; Fang, Liang

    2017-11-01

    Black silicon (Si) photoelectrodes are promising for improving the performance of photoelectrochemical (PEC) water splitting. Here, we report the fabrication of p-black Si and n+p-black Si photocathodes via a controllable copper-assisted catalyzed etching method. The etching process affects only the topmost less than 200 nm of Si and is independent of the surface doping. The synergistic effects of the excellent light harvesting of the black Si and the improved charge transfer properties of the p-n junction boost the production and utilization of photogenerated carriers. The mean reflectance of the pristine Si samples is about 10% from 400 to 950 nm, while that of the black Si samples is reduced as low as 5%. In addition, the PEC properties of the n+p-black Si photocathode can be further enhanced by depositing a cobalt (Co) layer. Compared with the p-Si sample, the onset potential of the Co/n+p-black Si photocathode is positively shifted by 560 mV to 0.33 V vs. reversible hydrogen electrode and the saturation photocurrent density is increased from 22.7 to 32.6 mA/cm2. The design of the Co/n+p-black Si photocathode offers an efficient strategy for preparing PEC solar energy conversion devices.

  9. Photoconductivity enhancement and charge transport properties in ruthenium-containing block copolymer/carbon nanotube hybrids.

    Science.gov (United States)

    Lo, Kin Cheung; Hau, King In; Chan, Wai Kin

    2018-04-05

    Functional polymer/carbon nanotube (CNT) hybrid materials can serve as a good model for light harvesting systems based on CNTs. This paper presents the synthesis of block copolymer/CNT hybrids and the characterization of their photocurrent responses by both experimental and computational approaches. A series of functional diblock copolymers was synthesized by reversible addition-fragmentation chain transfer polymerizations for the dispersion and functionalization of CNTs. The block copolymers contain photosensitizing ruthenium complexes and modified pyrene-based anchoring units. The photocurrent responses of the polymer/CNT hybrids were measured by photoconductive atomic force microscopy (PCAFM), from which the experimental data were analyzed by vigorous statistical models. The difference in photocurrent response among different hybrids was correlated to the conformations of the hybrids, which were elucidated by molecular dynamics simulations, and the electronic properties of polymers. The photoresponse of the block copolymer/CNT hybrids can be enhanced by introducing an electron-accepting block between the photosensitizing block and the CNT. We have demonstrated that the application of a rigorous statistical methodology can unravel the charge transport properties of these hybrid materials and provide general guidelines for the design of molecular light harvesting systems.

  10. Mechanical and tribological properties of silicon nitride films synthesized by ion beam enhanced deposition

    International Nuclear Information System (INIS)

    Chen Yuanru; Li Shizhuo; Zhang Xushou; Liu Hong; Yang Genqing; Qu Baochun

    1991-01-01

    This article describes preliminary investigations of mechanical and tribological properties of silicon nitride film formed by ion beam enhanced deposition (IBED) on GH37 (Ni-based alloys) steel. The films were synthesized by silicon vapor deposition with a rate of 1 A/s and by 40 keV nitrogen ion bombardment simultaneously. The thickness of the film was about 5000 A. X-ray photoelectron spectroscopy and infrared absorption spectroscopy revealed that a stoichiometric Si 3 N 4 film was formed. The observation of TEM showed that the IBED Si 3 N 4 film normally had an amorphous structure. However, electron diffraction patterns revealed a certain crystallinity. The mechanical and tribological properties of the films were investigated with a scratch tester, microhardness meter, and a ball-on-disc tribometer respectively. Results show that the adhesive strength between film and substrate is about 51 N, the Vickers microhardness with a load of 0.2 N is 980, the friction coefficient measured for steel against silicon nitride film ranges from 0.1 to 0.15, and the wear rate of coatings is about 6.8x10 -5 mm 3 /(mN). Finally, the relationship among thermal annealing, crystallinity and tribological characteristics of the Si 3 N 4 film is discussed. (orig.)

  11. Enhanced impact properties of cementitious composites reinforced with pultruded flax/polymeric matrix fabric

    Directory of Open Access Journals (Sweden)

    Magdi El-Messiry

    2017-09-01

    Full Text Available Fiber reinforced concrete (FRC has become increasingly applied in civil engineering in the last decades. Natural fiber fabric reinforced cement composites are considered to prevent damage resulting from an impact loading on the cementite plate. Flax woven fabric that has a high energy absorption capability was chosen. To increase the interfacial shear properties, the fabric was pultruded with different matrix properties that affect the strength and toughness of the pultruded fabric. In this study, three fabric structures are used to increase the anchoring of the cement in the fabric. The compressive strength and the impact energy were measured. The results revealed that pultruded fabric reinforced cement composite (PFRC absorbs much more impact energy. PFRC under impact loading has more micro cracks, while plain cement specimen shows brittle failure. The compressive test results of PFRC indicate that flax fiber fabric polymer enhanced compressive strength remarkably. Fiber reinforcement is a very effective in improving the impact resistance of PFRC. The study defines the influence factors that control the energy dissipation of the composite, which are the hardness of the polymer and the fabric cover factor. Significant correlation between impact energy and compressive strength was proved.

  12. Polyaniline/carbon nanotube/CdS quantum dot composites with enhanced optical and electrical properties

    Energy Technology Data Exchange (ETDEWEB)

    Goswami, Mrinmoy [Department of Physics, National Institute of Technology, Durgapur, 713209 (India); Ghosh, Ranajit, E-mail: ghosh.ranajit@gmail.com [CSIR-Central Mechanical Engineering Research Institute, Durgapur, 713209 (India); Maruyama, Takahiro [Department of Applied Chemistry, Meijo University, Nagoya, 4688502 (Japan); Meikap, Ajit Kumar [Department of Physics, National Institute of Technology, Durgapur, 713209 (India)

    2016-02-28

    Graphical abstract: - Highlights: • A new kind of polyaniline/carbon nanotube/CdS quantum dot composites have been synthesized via in-situ polymerization of aniline monomer. • A degree of increase in conductivity. • Size-dependent optical properties of CdS quantum dots have been observed. - Abstract: A new kind of polyaniline/carbon nanotube/CdS quantum dot composites have been developed via in-situ polymerization of aniline monomer in the presence of dispersed CdS quantum dots (size: 2.7–4.8 nm) and multi-walled carbon nanotubes (CNT), which exhibits enhanced optical and electrical properties. The existences of 1st order, 2nd order, and 3rd order longitudinal optical phonon modes, strongly indicate the high quality of synthesized CdS quantum dots. The occurrence of red shift of free exciton energy in photoluminescence is due to size dependent quantum confinement effect of CdS. The conductivity of the composites (for example PANI/CNT/CdS (2 wt.% CdS)) is increased by about 7 of magnitude compared to that of pure PANI indicating a charge transfer between CNT and polymer via CdS quantum dots. This advanced material has a great potential for high-performance of electro-optical applications.

  13. Enhanced protective properties and UV stability of epoxy/graphene nanocomposite coating on stainless steel

    Directory of Open Access Journals (Sweden)

    H. Alhumade

    2016-12-01

    Full Text Available Epoxy-Graphene (E/G nanocomposites with different loading of graphene were prepared via in situ prepolymerization and evaluated as protective coating for Stainless Steel 304 (SS304. The prepolymer composites were spin coated on SS304 substrates and thermally cured. Transmission Electron Microscopy (TEM and Scanning Electron Microscopy (SEM were utilized to examine the dispersion of graphene in the epoxy matrix. Epoxy and E/G nanocomposites were characterized using X-ray diffraction (XRD and Fourier Transform Infrared (FTIR techniques and the thermal behavior of the prepared coatings is analyzed using Thermogravimetric analysis (TGA and Differential scanning calorimetry (DSC. The corrosion protection properties of the prepared coatings were evaluated using Electrochemical Impedance Spectroscopy (EIS and Cyclic Voltammetry (CV measurements. In addition to corrosion mitigation properties, the long-term adhesion performance of the coatings was evaluated by measuring the adhesion of the coatings to the SS304 substrate after 60 days of exposure to 3.5 wt% NaCl medium. The effects of graphene loading on the impact resistance, flexibility, and UV stability of the coating are analyzed and discussed. SEM was utilized to evaluate post adhesion and UV stability results. The results indicate that very low graphene loading up to 0.5 wt % significantly enhances the corrosion protection, UV stability, and impact resistance of epoxy coatings.

  14. Temperature-Induced Lattice Relaxation of Perovskite Crystal Enhances Optoelectronic Properties and Solar Cell Performance

    KAUST Repository

    Banavoth, Murali

    2016-12-14

    Hybrid organic-inorganic perovskite crystals have recently become one of the most important classes of photoactive materials in the solar cell and optoelectronic communities. Albeit improvements have focused on state-of-the-art technology including various fabrication methods, device architectures, and surface passivation, progress is yet to be made in understanding the actual operational temperature on the electronic properties and the device performances. Therefore, the substantial effect of temperature on the optoelectronic properties, charge separation, charge recombination dynamics, and photoconversion efficiency are explored. The results clearly demonstrated a significant enhancement in the carrier mobility, photocurrent, charge carrier lifetime, and solar cell performance in the 60 ± 5 °C temperature range. In this temperature range, perovskite crystal exhibits a highly symmetrical relaxed cubic structure with well-aligned domains that are perpendicular to a principal axis, thereby remarkably improving the device operation. This finding provides a new key variable component and paves the way toward using perovskite crystals in highly efficient photovoltaic cells.

  15. Enhancing Effect of Glycerol on the Tensile Properties of Bombyx mori Cocoon Sericin Films

    Directory of Open Access Journals (Sweden)

    Liangjun Zhu

    2011-05-01

    Full Text Available An environmental physical method described herein was developed to improve the tensile properties of Bombyx mori cocoon sericin films, by using the plasticizer of glycerol, which has a nontoxic effect compared with other chemical crosslinkers. The changes in the tensile characteristics and the structure of glycerolated (0–40 wt% of glycerol sericin films were investigated. Sericin films, both in dry and wet states, showed enhanced tensile properties, which might be regulated by the addition of different concentrations of glycerol. The introduction of glycerol results in the higher amorphous structure in sericin films as evidenced by analysis of attenuated total reflection Fourier transform infrared (ATR-FTIR spectra, thermogravimetry (TGA and differential scanning calorimetry (DSC curves. Scanning Electron Microscopy (SEM observation revealed that glycerol was homogeneously blended with sericin molecules when its content was 10 wt%, while a small amount of redundant glycerol emerged on the surface of sericin films when its content was increased to 20 wt% or higher. Our results suggest that the introduction of glycerol is a novel nontoxic strategy which can improve the mechanical features of sericin-based materials and subsequently promote the feasibility of its application in tissue engineering.

  16. Residual Stress Induced Mechanical Property Enhancement in Steel Encapsulated Light Metal Matrix Composites

    Science.gov (United States)

    Fudger, Sean James

    Macro hybridized systems consisting of steel encapsulated light metal matrix composites (MMCs) were produced with the goal of creating a low cost/light weight composite system with enhanced mechanical properties. MMCs are frequently incorporated into advanced material systems due to their tailorable material properties. However, they often have insufficient ductility for many structural applications. The macro hybridized systems take advantage of the high strength, modulus, and damage tolerance of steels and high specific stiffness and low density of MMCs while mitigating the high density of steels and the poor ductility of MMCs. Furthermore, a coefficient of thermal expansion (CTE) mismatch induced residual compressive stress method is utilized as a means of improving the ductility of the MMCs and overall efficiency of the macro hybridized systems. Systems consisting of an A36, 304 stainless steel, or NitronicRTM 50 stainless steel shell filled with an Al-SiC, Al-Al2O3, or Mg-B4C MMC are evaluated in this work. Upon cooling from processing temperatures, residual strains are generated due to a CTE mismatch between each of the phases. The resulting systems offer higher specific properties and a more structurally efficient system can be attained. Mechanical testing was performed and improvements in yield stress, ultimate tensile stress, and ductility were observed. However, the combination of these dissimilar materials often results in the formation of intermetallic compounds. In certain loading situations, these typically brittle intermetallic layers can result in degraded performance. X-ray Diffraction (XRD), X-ray Energy Dispersive Spectroscopy (EDS), and Electron Backscatter Diffraction (EBSD) are utilized to characterize the intermetallic layer formation at the interface between the steel and MMC. As the residual stress condition in each phase has a large impact on the mechanical property improvement, accurate quantification of these strains/stresses is

  17. Enhanced production of bacterial cellulose by using a biofilm reactor and its material property analysis

    Directory of Open Access Journals (Sweden)

    Demirci Ali

    2009-07-01

    Full Text Available Abstract Bacterial cellulose has been used in the food industry for applications such as low-calorie desserts, salads, and fabricated foods. It has also been used in the paper manufacturing industry to enhance paper strength, the electronics industry in acoustic diaphragms for audio speakers, the pharmaceutical industry as filtration membranes, and in the medical field as wound dressing and artificial skin material. In this study, different types of plastic composite support (PCS were implemented separately within a fermentation medium in order to enhance bacterial cellulose (BC production by Acetobacter xylinum. The optimal composition of nutritious compounds in PCS was chosen based on the amount of BC produced. The selected PCS was implemented within a bioreactor to examine the effects on BC production in a batch fermentation. The produced BC was analyzed using X-ray diffraction (XRD, field emission scanning electron microscopy (FESEM, thermogravimetric analysis (TGA, and dynamic mechanical analysis (DMA. Among thirteen types of PCS, the type SFYR+ was selected as solid support for BC production by A. xylinum in a batch biofilm reactor due to its high nitrogen content, moderate nitrogen leaching rate, and sufficient biomass attached on PCS. The PCS biofilm reactor yielded BC production (7.05 g/L that was 2.5-fold greater than the control (2.82 g/L. The XRD results indicated that the PCS-grown BC exhibited higher crystallinity (93% and similar crystal size (5.2 nm to the control. FESEM results showed the attachment of A. xylinum on PCS, producing an interweaving BC product. TGA results demonstrated that PCS-grown BC had about 95% water retention ability, which was lower than BC produced within suspended-cell reactor. PCS-grown BC also exhibited higher Tmax compared to the control. Finally, DMA results showed that BC from the PCS biofilm reactor increased its mechanical property values, i.e., stress at break and Young's modulus when compared to

  18. Ambient redox synthesis of vanadium-doped manganese dioxide nanoparticles and their enhanced zinc storage properties

    Energy Technology Data Exchange (ETDEWEB)

    Alfaruqi, Muhammad Hilmy; Islam, Saiful; Mathew, Vinod; Song, Jinju; Kim, Sungjin; Tung, Duong Pham; Jo, Jeonggeun; Kim, Seokhun; Baboo, Joseph Paul; Xiu, Zhiliang; Kim, Jaekook, E-mail: jaekook@chonnam.ac.kr

    2017-05-15

    Highlights: • The V-doped MnO{sub 2} was prepared by a simple ambient redox reaction. • The V-doped MnO{sub 2} was tested as a cathode in aqueous zinc-ion batteries (ZIBs). • The doped cathode showed better zinc-storage properties than the bare cathode. • The present study facilitates the development of safe and reliable aqueous ZIBs. - Abstract: In this work, we demonstrate the first use of a V-doped MnO{sub 2} nanoparticle electrode for zinc-ion battery (ZIB) applications. The V-doped MnO{sub 2} was prepared via a simple redox reaction and the X-ray diffraction studies confirmed the formation of pure MnO{sub 2}, accompanied by an anisotropic expansion of MnO{sub 2} lattice, suggesting the incorporation of V-ions into the MnO{sub 2} framework. V doping of MnO{sub 2} not only increased the specific surface area but also improved the electronic conductivity. When Zn-storage properties were tested, the V-doped MnO{sub 2} electrode registered a higher discharge capacity of 266 mAh g{sup −1} compared to 213 mAh g{sup −1} for the pure MnO{sub 2} electrode. On prolonged cycling, the doped electrode retained 31% higher capacity than that of the bare MnO{sub 2} electrode and thereby demonstrated superior cycling performance. This study may pave the way towards understanding the enhancement of the energy storage properties via doping in electrodes of aqueous ZIB applications and also furthers the efforts for the practical realization of a potential eco-friendly battery system.

  19. Carbon Nanotube Sheet Scrolled Fiber Composite for Enhanced Interfacial Mechanical Properties

    Science.gov (United States)

    Kokkada Ravindranath, Pruthul

    The high tensile strength of Polymer Matrix Composites (PMC) is derived from the high tensile strength of the embedded carbon fibers. However, their compressive strength is significantly lower than their tensile strength, as they tend to fail through micro-buckling, under compressive loading. Fiber misalignment and the presence of voids created during the manufacturing processes, add to the further reduction in the compressive strength of the composites. Hence, there is more scope for improvement. Since, the matrix is primarily responsible for the shear load transfer and dictating the critical buckling load of the fibers by constraining the fibers from buckling, to improve the interfacial mechanical properties of the composite, it is important to modify the polymer matrix, fibers and/or the interface. In this dissertation, a novel approach to enhance the polymer matrix-fiber interface region has been discussed. This approach involves spiral wrapping carbon nanotube (CNT) sheet around individual carbon fiber or fiber tow, at room temperature at a prescribed wrapping angle (bias angle), and then embed the scrolled fiber in a resin matrix. The polymer infiltrates into the nanopores of the multilayer CNT sheet to form CNT/polymer nanocomposite surrounding fiber, and due to the mechanical interlocking, provides reinforcement to the interface region between fiber and polymer matrix. This method of nano-fabrication has the potential to improve the mechanical properties of the fiber-matrix interphase, without degrading the fiber properties. The effect of introducing Multi-Walled Carbon Nanotubes (MWNT) in the polymer matrix was studied by analyzing the atomistic model of the epoxy (EPON-862) and the embedded MWNTs. A multi-scale method was utilized by using molecular dynamics (MD) simulations on the nanoscale model of the epoxy with and without the MWNTs to calculate compressive strength of the composite and predict the enhancement in the composite material. The influence

  20. Antiproliferative and Antibacterial Activities of Cirsium scabrum from Tunisia

    Directory of Open Access Journals (Sweden)

    Ramla Sahli

    2017-01-01

    Full Text Available Several Cirsium species are known for their uses in traditional medicine and consequently are studied for their phytochemical content and their biological activities. In the framework of a previous study conducted on eight extremophile plants from Tunisia, we highlighted that the crude methanolic extract of C. scabrum, a not investigated thistle, showed moderate but quite selective cytotoxic activity against the cancerous cell line J774 compared to the noncancerous cell line WI38 (IC50 = 11.53 μg/ml on J774, IC50 = 29.89 µg/ml on WI38, and selectivity index = 2.6. In the current study, the partitions of the leaves of C. scabrum were analyzed for their antiproliferative activity on the same cell lines. From the most active petroleum ether partition, we isolated four triterpenoids including lupeol, taraxasterol acetate, and a (1 : 1 mixture of 25-hydroperoxycycloart-23-en-3β-ol and 24-hydroperoxycycloart-25-en-3β-ol. These two cycloartane-type triterpenoids are mostly responsible for this cytotoxic activity. On the other hand, the antimicrobial potential of this plant was also evaluated against 36 microorganisms. The moderate antibacterial activity against 6 Staphylococcus aureus and 2 Dermabacter hominis strains is mainly attributed to the butanol partition whose major compounds are glycosides of flavones.

  1. Antiproliferative and Antibacterial Activities of Cirsium scabrum from Tunisia.

    Science.gov (United States)

    Sahli, Ramla; Rivière, Céline; Dufloer, Cédric; Beaufay, Claire; Neut, Christel; Bero, Joanne; Hennebelle, Thierry; Roumy, Vincent; Ksouri, Riadh; Quetin-Leclercq, Joelle; Sahpaz, Sevser

    2017-01-01

    Several Cirsium species are known for their uses in traditional medicine and consequently are studied for their phytochemical content and their biological activities. In the framework of a previous study conducted on eight extremophile plants from Tunisia, we highlighted that the crude methanolic extract of C. scabrum , a not investigated thistle, showed moderate but quite selective cytotoxic activity against the cancerous cell line J774 compared to the noncancerous cell line WI38 (IC 50 = 11.53  μ g/ml on J774, IC 50 = 29.89  µ g/ml on WI38, and selectivity index = 2.6). In the current study, the partitions of the leaves of C. scabrum were analyzed for their antiproliferative activity on the same cell lines. From the most active petroleum ether partition, we isolated four triterpenoids including lupeol, taraxasterol acetate, and a (1 : 1) mixture of 25-hydroperoxycycloart-23-en-3 β -ol and 24-hydroperoxycycloart-25-en-3 β -ol. These two cycloartane-type triterpenoids are mostly responsible for this cytotoxic activity. On the other hand, the antimicrobial potential of this plant was also evaluated against 36 microorganisms. The moderate antibacterial activity against 6 Staphylococcus aureus and 2 Dermabacter hominis strains is mainly attributed to the butanol partition whose major compounds are glycosides of flavones.

  2. Antiproliferative Constituents of Geopropolis from the Bee Melipona scutellaris.

    Science.gov (United States)

    da Cunha, Marcos Guilherme; Rosalen, Pedro Luiz; Franchin, Marcelo; de Alencar, Severino Matias; Ikegaki, Masaharu; Ransom, Tanya; Beutler, John Albert

    2016-02-01

    Fractionation of geopropolis from Melipona scutellaris, guided by antiproliferative activity against two colon cancer cell lines (COLO205 and KM12), led to the isolation of two new cinnamic acid esters, mammea-type coumarins 5,7-dihydroxy-6-(3-methyl-2-butenyl)-8-(4-cinnamoyl-3-methyl-1-oxobutyl)-4-propyl-coumarin (1) and 5,7-dihydroxy-6-(4-cinnamoyl-3-methyl-1-oxobutyl)-4-phenylcoumarin (2), along with five known coumarins, mammeigin (3), hydroxymammeigin (4), mammeisin (5), cinnamoyloxy-mammeisin (6), and mammein (7), and the prenylated benzophenone ent-nemorosone (8). Among the isolated compounds, 5 and 7 showed the highest cell growth inhibition against COLO205 (GI50 9.7 and 10.7 µM, respectively) and KM12 (GI50 12.0 and 10.9 µM, respectively). The presence of these compounds suggests that plants of Clusiaceae family, especially the genera Kielmeyera and Clusia, are likely to be major sources of geopropolis produced by M. scutellaris. Georg Thieme Verlag KG Stuttgart · New York.

  3. DNA Mismatch Binding and Antiproliferative Activity of Rhodium Metalloinsertors

    Science.gov (United States)

    Ernst, Russell J.; Song, Hang; Barton, Jacqueline K.

    2009-01-01

    Deficiencies in mismatch repair (MMR) are associated with carcinogenesis. Rhodium metalloinsertors bind to DNA base mismatches with high specificity and inhibit cellular proliferation preferentially in MMR-deficient cells versus MMR-proficient cells. A family of chrysenequinone diimine complexes of rhodium with varying ancillary ligands that serve as DNA metalloinsertors has been synthesized, and both DNA mismatch binding affinities and antiproliferative activities against the human colorectal carcinoma cell lines HCT116N and HCT116O, an isogenic model system for MMR deficiency, have been determined. DNA photocleavage experiments reveal that all complexes bind to the mismatch sites with high specificities; DNA binding affinities to oligonucleotides containing single base CA and CC mismatches, obtained through photocleavage titration or competition, vary from 104 to 108 M−1 for the series of complexes. Significantly, binding affinities are found to be inversely related to ancillary ligand size and directly related to differential inhibition of the HCT116 cell lines. The observed trend in binding affinity is consistent with the metalloinsertion mode where the complex binds from the minor groove with ejection of mismatched base pairs. The correlation between binding affinity and targeting of the MMR-deficient cell line suggests that rhodium metalloinsertors exert their selective biological effects on MMR-deficient cells through mismatch binding in vivo. PMID:19175313

  4. Antiproliferative compounds of Cyphostemma greveana from a Madagascar dry forest.

    Science.gov (United States)

    Cao, Shugeng; Hou, Yanpeng; Brodie, Peggy; Miller, James S; Randrianaivo, Richard; Rakotobe, Etienne; Rasamison, Vincent E; Kingston, David G I

    2011-04-01

    Bioassay-guided fractionation of the EtOH extracts obtained from a plant identified as Cyphostemma greveana Desc. (Vitaceae) led to the identification of one macrolide, lasiodiplodin (1), three sesquiterpenoids, 12-hydroxy-15-oxoselina-4,11-diene (2), 1β,6α-dihydroxyeudesm-4(15)-ene (3), and (7R*)-opposit-4(15)-ene-1β,7-diol (5), and a new diterpenoid, 16,18-dihydroxykolavenic acid lactone (4). All the isolates were tested against the A2780 human ovarian cancer cell line, and compound 4 and a fraction containing 5 as the major constituent showed antiproliferative activities with IC(50) values of 0.44 μM (0.14 μg/ml) and 0.045 μg/ml, respectively. A partial synthesis of compound 5 was carried out, but the pure synthetic compound was inactive, indicating that the activity of the fraction containing it must be due to a very minor and as yet unidentified substance. Copyright © 2011 Verlag Helvetica Chimica Acta AG, Zürich.

  5. The antiproliferative and apoptotic effects of apigenin on glioblastoma cells.

    Science.gov (United States)

    Stump, Trevor A; Santee, Brittany N; Williams, Lauren P; Kunze, Rachel A; Heinze, Chelsae E; Huseman, Eric D; Gryka, Rebecca J; Simpson, Denise S; Amos, Samson

    2017-07-01

    Glioblastoma (GBM) is highly proliferative, infiltrative, malignant and the most deadly form of brain tumour. The epidermal growth factor receptor (EGFR) is overexpressed, amplified and mutated in GBM and has been shown to play key and important roles in the proliferation, growth and survival of this tumour. The goal of our study was to investigate the antiproliferative, apoptotic and molecular effects of apigenin in GBM. Proliferation and viability tests were carried out using the trypan blue exclusion, MTT and lactate dehydrogenase (LDH) assays. Flow cytometry was used to examine the effects of apigenin on the cell cycle check-points. In addition, we determined the effects of apigenin on EGFR-mediated signalling pathways by Western blot analyses. Our results showed that apigenin reduced cell viability and proliferation in a dose- and time-dependent manner while increasing cytotoxicity in GBM cells. Treatment with apigenin-induced is poly ADP-ribose polymerase (PARP) cleavage and caused cell cycle arrest at the G2M checkpoint. Furthermore, our data revealed that apigenin inhibited EGFR-mediated phosphorylation of mitogen-activated protein kinase (MAPK), AKT and mammalian target of rapamycin (mTOR) signalling pathways and attenuated the expression of Bcl-xL. Our results demonstrated that apigenin has potent inhibitory effects on pathways involved in GBM proliferation and survival and could potentially be used as a therapeutic agent for GBM. © 2017 Royal Pharmaceutical Society.

  6. Owning genetic information and gene enhancement techniques: why privacy and property rights may undermine social control of the human genome.

    Science.gov (United States)

    Moore, A D

    2000-04-01

    In this article I argue that the proper subjects of intangible property claims include medical records, genetic profiles, and gene enhancement techniques. Coupled with a right to privacy these intangible property rights allow individuals a zone of control that will, in most cases, justifiably exclude governmental or societal invasions into private domains. I argue that the threshold for overriding privacy rights and intangible property rights is higher, in relation to genetic enhancement techniques and sensitive personal information, than is commonly suggested. Once the bar is raised, so-to-speak, the burden of overriding it is formidable. Thus many policy decisions that have been recently proposed or enacted--citywide audio and video surveillance, law enforcement DNA sweeps, genetic profiling, national bans on genetic testing and enhancement of humans, to name a few--will have to be backed by very strong arguments.

  7. Essential Oil from Myrica rubra Leaves Potentiated Antiproliferative and Prooxidative Effect of Doxorubicin and its Accumulation in Intestinal Cancer Cells.

    Science.gov (United States)

    Ambrož, Martin; Hanušová, Veronika; Skarka, Adam; Boušová, Iva; Králová, Věra; Langhasová, Lenka; Skálová, Lenka

    2016-01-01

    Essential oil from the leaves of Myrica rubra, a subtropical Asian fruit tree traditionally used in folk medicines, has a significant antiproliferative effect in several intestinal cancer cell lines. Doxorubicin belongs to the most important cytostatics used in cancer therapy. The present study was designed to evaluate the effects of defined essential oil from M. rubra leaves on efficacy, prooxidative effect, and accumulation of doxorubicin in cancer cell lines and in non-cancerous cells. For this purpose, intestinal adenocarcinoma CaCo2 cells were used. Human fibroblasts (periodontal ligament) and a primary culture of rat hepatocytes served as models of non-cancerous cells. The results showed that the sole essential oil from M. rubra has a strong prooxidative effect in cancer cells while it acts as a mild antioxidant in hepatocytes. Combined with doxorubicin, the essential oil enhanced the antiproliferative and prooxidative effects of doxorubicin in cancer cells. At higher concentrations, synergism of doxorubicin and essential oil from M. rubra was proved. In non-cancerous cells, the essential oil did not affect the toxicity of doxorubicin and the doxorubicin-mediated reactive oxygen species formation. The essential oil increased the intracellular concentration of doxorubicin and enhanced selectively the doxorubicin accumulation in nuclei of cancer cells. Taken together, essential oil from M. rubra leaves could be able to improve the doxorubicin efficacy in cancer cells due to an increased reactive oxygen species production, and the doxorubicin accumulation in nuclei of cancer cells. Georg Thieme Verlag KG Stuttgart · New York.

  8. Enhanced mechanical properties and increased corrosion resistance of a biodegradable magnesium alloy by plasma electrolytic oxidation (PEO)

    International Nuclear Information System (INIS)

    White, Leon; Koo, Youngmi; Neralla, Sudheer; Sankar, Jagannathan; Yun, Yeoheung

    2016-01-01

    Highlights: • Plasma electrolytic oxidation (PEO) method was developed to control corrosion, porosity, and mechanical property. • Mechanical properties of PEO-coated AZ31 alloys were affected by the different electrolyte. • Mechanical properties and corrosion resistance of PEO-coated AZ31 alloys were compared with uncoated one. - Abstract: We report the enhanced mechanical properties of AZ31 magnesium alloys by plasma electrolytic oxidation (PEO) coating in NaOH, Na_2SiO_3, KF and NaH_2PO_4·2H_2O containing electrolytes. Mechanical properties including wear resistance, surface hardness and elastic modulus were increased for PEO-coated AZ31 Mg alloys (PEO-AZ31). DC polarization in Hank's solution indicating that the corrosion resistance significantly increased for PEO-coating in KF-contained electrolyte. Based on these results, the PEO coating method shows promising potential for use in biodegradable implant applications where tunable corrosion and mechanical properties are needed.

  9. Regeneration of Achilles' tendon: the role of dynamic stimulation for enhanced cell proliferation and mechanical properties.

    Science.gov (United States)

    Lee, Jongman; Guarino, Vincenzo; Gloria, Antonio; Ambrosio, Luigi; Tae, Giyoong; Kim, Young Ha; Jung, Youngmee; Kim, Sang-Heon; Kim, Soo Hyun

    2010-01-01

    The tissue engineering of tendon was studied using highly elastic poly(L-lactide-co-epsilon-caprolactone) (PLCL) scaffolds and focusing on the effect of dynamic tensile stimulation. Tenocytes from rabbit Achilles tendon were seeded (1.0 x 10(6) cells/scaffold) onto porous PLCL scaffolds and cultured for periods of 2 weeks and 4 weeks. This was performed in a static system and also in a bioreactor equipped with tensile modulation which mimicked the environmental surroundings of tendons with respect to tensile extension. The degradation of the polymeric scaffolds during the culture was relatively slow. However, there was an indication that cells accelerated the degradation of PLCL scaffolds. The scaffold/cell adducts from the static culture exhibited inferior strength (at 2 weeks 350 kPa, 4 weeks 300 kPa) compared to the control without cells (at 2 weeks 460 kPa, 4 weeks 340 kPa), indicating that the cells contributed to the enhanced degradation. On the contrary, the corresponding values of the adducts from the dynamic culture (at 2 weeks 430 kPa, 4 weeks 370 kPa) were similar to, or higher than, those from the control. This could be explained by the increased quantity of cells and neo-tissues in the case of dynamic culture compensating for the loss in tensile strength. Compared with static and dynamic culture conditions, mechanical stimulation played a crucial role in the regeneration of tendon tissue. In the case of the dynamic culture system, cell proliferation was enhanced and secretion of collagen type I was increased, as evidenced by DNA assay and histological and immunofluorescence analysis. Thus, tendon regeneration, indicated by improved mechanical and biological properties, was demonstrated, confirming the effect of mechanical stimulation. It could be concluded that the dynamic tensile stimulation appeared to be an essential factor in tendon/ligament tissue engineering, and that elastic PLCL co-polymers could be very beneficial in this process.

  10. Highly Enhanced Gas Adsorption Properties in Vertically Aligned MoS2 Layers.

    Science.gov (United States)

    Cho, Soo-Yeon; Kim, Seon Joon; Lee, Youhan; Kim, Jong-Seon; Jung, Woo-Bin; Yoo, Hae-Wook; Kim, Jihan; Jung, Hee-Tae

    2015-09-22

    In this work, we demonstrate that gas adsorption is significantly higher in edge sites of vertically aligned MoS2 compared to that of the conventional basal plane exposed MoS2 films. To compare the effect of the alignment of MoS2 on the gas adsorption properties, we synthesized three distinct MoS2 films with different alignment directions ((1) horizontally aligned MoS2 (basal plane exposed), (2) mixture of horizontally aligned MoS2 and vertically aligned layers (basal and edge exposed), and (3) vertically aligned MoS2 (edge exposed)) by using rapid sulfurization method of CVD process. Vertically aligned MoS2 film shows about 5-fold enhanced sensitivity to NO2 gas molecules compared to horizontally aligned MoS2 film. Vertically aligned MoS2 has superior resistance variation compared to horizontally aligned MoS2 even with same surface area exposed to identical concentration of gas molecules. We found that electrical response to target gas molecules correlates directly with the density of the exposed edge sites of MoS2 due to high adsorption of gas molecules onto edge sites of vertically aligned MoS2. Density functional theory (DFT) calculations corroborate the experimental results as stronger NO2 binding energies are computed for multiple configurations near the edge sites of MoS2, which verifies that electrical response to target gas molecules (NO2) correlates directly with the density of the exposed edge sites of MoS2 due to high adsorption of gas molecules onto edge sites of vertically aligned MoS2. We believe that this observation extends to other 2D TMD materials as well as MoS2 and can be applied to significantly enhance the gas sensor performance in these materials.

  11. A Guide for Using Mechanical Stimulation to Enhance Tissue-Engineered Articular Cartilage Properties.

    Science.gov (United States)

    Salinas, Evelia Y; Hu, Jerry C; Athanasiou, Kyriacos

    2018-04-26

    The use of tissue-engineered articular cartilage (TEAC) constructs has the potential to become a powerful treatment option for cartilage lesions resulting from trauma or early stages of pathology. Although fundamental tissue-engineering strategies based on the use of scaffolds, cells, and signals have been developed, techniques that lead to biomimetic AC constructs that can be translated to in vivo use are yet to be fully confirmed. Mechanical stimulation during tissue culture can be an effective strategy to enhance the mechanical, structural, and cellular properties of tissue-engineered constructs toward mimicking those of native AC. This review focuses on the use of mechanical stimulation to attain and enhance the properties of AC constructs needed to translate these implants to the clinic. In vivo, mechanical loading at maximal and supramaximal physiological levels has been shown to be detrimental to AC through the development of degenerative changes. In contrast, multiple studies have revealed that during culture, mechanical stimulation within narrow ranges of magnitude and duration can produce anisotropic, mechanically robust AC constructs with high cellular viability. Significant progress has been made in evaluating a variety of mechanical stimulation techniques on TEAC, either alone or in combination with other stimuli. These advancements include determining and optimizing efficacious loading parameters (e.g., duration and frequency) to yield improvements in construct design criteria, such as collagen II content, compressive stiffness, cell viability, and fiber organization. With the advancement of mechanical stimulation as a potent strategy in AC tissue engineering, a compendium detailing the results achievable by various stimulus regimens would be of great use for researchers in academia and industry. The objective is to list the qualitative and quantitative effects that can be attained when direct compression, hydrostatic pressure, shear, and tensile

  12. Enhancement of antibacterial properties of polyurethanes by chitosan and heparin immobilization

    International Nuclear Information System (INIS)

    Kara, Filiz; Aksoy, E. Ayse; Yuksekdag, Zehranur; Aksoy, Serpil; Hasirci, Nesrin

    2015-01-01

    Graphical abstract: - Highlights: • Polyurethane elastomer was synthesized in medical purity. • Chitosan (CH) and heparin (Hep) were immobilized on polyurethane films. • Modification with CH and Hep increased hydrophilicity and surface free energy. • Immobilized films had high antibacterial activity against four bacteria. • Bacterial adhesion significantly decreased on the modified surfaces. - Abstract: Being antibacterial is a required property for the materials used in medical devices and instruments. Polyurethanes (PUs) are one class of polymers widely used in the production of devices that especially come in contact with blood (e.g. heart valves, blood vessels, vascular grafts and catheters). In this study, hexamethylene diisocyanate based polyurethanes (PUh) were synthesized and antibacterial and anti-adhesive properties were added by immobilizing chitosan (CH) and heparin (Hep) on the samples of PUh via a stepwise process. Chemistry and topography of the modified film samples (PUh-CH and PUh-CH-Hep) were examined by Fourier Transform Infrared Spectrophotometry-Attenuated Total Reflectance (FTIR-ATR), Electron Spectroscopy for Chemical Analysis (ESCA) and Atomic Force Microscopy (AFM), and surface free energy (SFE) values after each step were determined by goniometer. PUh-CH and PUh-CH-Hep samples were found to be antibacterial against Staphylococcus aureus (S. aureus) and Staphylococcus epidermidis (S. epidermidis) (both Gram positive) and Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) (both Gram negative) bacteria, and bacterial adhesion results showed a significant decrease in the number of viable bacteria on both modified samples where PUh-CH-Hep was the most effective. The findings of this study show that polymeric surfaces can be effectively modified and converted to be antibacterial by chitosan and heparin immobilization, and presence of both chemicals enhance efficacy against bacteria.

  13. Intercropping enhances productivity and maintains the most soil fertility properties relative to sole cropping.

    Directory of Open Access Journals (Sweden)

    Zhi-Gang Wang

    Full Text Available Yield and nutrient acquisition advantages are frequently found in intercropping systems. However, there are few published reports on soil fertility in intercropping relative to monocultures. A field experiment was therefore established in 2009 in Gansu province, northwest China. The treatments comprised maize/faba bean, maize/soybean, maize/chickpea and maize/turnip intercropping, and their correspoding monocropping. In 2011 (the 3rd year and 2012 (the 4th year the yields and some soil chemical properties and enzyme activities were examined after all crop species were harvested or at later growth stages. Both grain yields and nutrient acquisition were significantly greater in all four intercropping systems than corresponding monocropping over two years. Generally, soil organic matter (OM did not differ significantly from monocropping but did increase in maize/chickpea in 2012 and maize/turnip in both years. Soil total N (TN did not differ between intercropping and monocropping in either year with the sole exception of maize/faba bean intercropping receiving 80 kg P ha-1 in 2011. Intercropping significantly reduced soil Olsen-P only in 2012, soil exchangeable K in both years, soil cation exchangeable capacity (CEC in 2012, and soil pH in 2012. In the majority of cases soil enzyme activities did not differ across all the cropping systems at different P application rates compared to monocrops, with the exception of soil acid phosphatase activity which was higher in maize/legume intercropping than in the corresponding monocrops at 40 kg ha-1 P in 2011. P fertilization can alleviate the decline in soil Olsen-P and in soil CEC to some extent. In summary, intercropping enhanced productivity and maintained the majority of soil fertility properties for at least three to four years, especially at suitable P application rates. The results indicate that maize-based intercropping may be an efficient cropping system for sustainable agriculture with carefully

  14. Enhanced mechanical properties of thermosensitive chitosan hydrogel by silk fibers for cartilage tissue engineering

    International Nuclear Information System (INIS)

    Mirahmadi, Fereshteh; Tafazzoli-Shadpour, Mohammad; Shokrgozar, Mohammad Ali; Bonakdar, Shahin

    2013-01-01

    Articular cartilage has limited repair capability following traumatic injuries and current methods of treatment remain inefficient. Reconstructing cartilage provides a new way for cartilage repair and natural polymers are often used as scaffold because of their biocompatibility and biofunctionality. In this study, we added degummed chopped silk fibers and electrospun silk fibers to the thermosensitive chitosan/glycerophosphate hydrogels to reinforce two hydrogel constructs which were used as scaffold for hyaline cartilage regeneration. The gelation temperature and gelation time of hydrogel were analyzed by the rheometer and vial tilting method. Mechanical characterization was measured by uniaxial compression, indentation and dynamic mechanical analysis assay. Chondrocytes were then harvested from the knee joint of the New Zealand white rabbits and cultured in constructs. The cell proliferation, viability, production of glycosaminoglycans and collagen type II were assessed. The results showed that mechanical properties of the hydrogel were significantly enhanced when a hybrid with two layers of electrospun silk fibers was made. The results of GAG and collagen type II in cell-seeded scaffolds indicate support of the chondrogenic phenotype for chondrocytes with a significant increase in degummed silk fiber–hydrogel composite for GAG content and in two-layer electrospun fiber–hydrogel composite for Col II. It was concluded that these two modified scaffolds could be employed for cartilage tissue engineering. - Highlights: • Chitosan hydrogel composites fabricated by two forms of silk fiber • Silk fibers provide structural support for the hydrogel matrix. • The mechanical properties of hydrogel significantly improved by associating with silk. • Production of GAG and collagen type II was demonstrated within the scaffolds

  15. Enhanced photoelectrochemical properties of 100 MeV Si8+ ion irradiated barium titanate thin films

    International Nuclear Information System (INIS)

    Solanki, Anjana; Choudhary, Surbhi; Satsangi, Vibha R.; Shrivastav, Rohit; Dass, Sahab

    2013-01-01

    Highlights: ► Effect of 100 MeV Si 8+ ion irradiation on photoelectrochemical (PEC) properties of BaTiO 3 thin films was studied. ► Films were deposited on Indium doped Tin Oxide (ITO) coated glass by sol–gel spin coating technique. ► Optimal irradiation fluence for best PEC response was 5 × 10 11 ion cm −2 . ► Maximum photocurrent density was observed to be 0.7 mA cm −2 at 0.4 V/SCE. ► Enhanced photo-conversion efficiency was due to maximum negative flatband potential, donor density and lowest resistivity. -- Abstract: Effects of high electronic energy deposition on the structure, surface topography, optical property and photoelectrochemical behavior of barium titanate (BaTiO 3 ) thin films were investigated by irradiating films with 100 MeV Si 8+ ions at different ion fluences in the range of 1 × 10 11 –2 × 10 13 ions cm −2 . BaTiO 3 thin films were deposited on indium tin oxide coated glass substrate by sol gel spin coating method. Irradiation induced modifications in the films were analyzed using the results from XRD, SEM, cross sectional SEM, AFM and UV–Vis spectrometry. Maximum photocurrent density of 0.7 mA cm −2 at 0.4 V/SCE and applied bias hydrogen conversion efficiency (ABPE) of 0.73% was observed for BaTiO 3 film irradiated at 5 × 10 11 ions cm −2 , which can be attributed to maximum negative value of the flatband potential and donor density and lowest resistivity

  16. Effects of particle shape and size on nanofluid properties for potential Enhanced Oil Recovery (EOR

    Directory of Open Access Journals (Sweden)

    Tengku Mohd Tengku Amran

    2016-01-01

    Full Text Available Application of Enhanced Oil Recovery (EOR in oil and gas industry is very important to increase oil recovery and prolong the lifetime of a reservoir but it has been very costly and losing properties of EOR agent due to harsh condition. Nanoparticles have been used in EOR application since they are not degradable in reservoir condition and used in smaller amount compared to polymer usage. Commonly, EOR techniques are focusing on increasing the sweep efficiency by controlling the mobility ratio between reservoir fluid and injected fluid. Thus, this research aimed to analyze the nanofluid viscosity at different particle size and shape, volumetric concentration and types of dispersing fluid, as well as to determine the oil recovery performance at different nanofluid concentration. The nanofluid viscosity was investigated at nanoparticle sizes of 15nm and 60nm and shapes of 15nm spherical-solid and porous. Five nanofluid samples with concentration ranging from 0.1wt.% to 7wt.% were used to investigate the effect of volumetric concentration. Distilled water, ethanol, ethylene glycol (EG and brine were used for the effect of dispersing fluids. Oil recovery was investigated at five different concentrations of nanofluid samples through flooding test. It was found that viscosity of nanofluid increased with decreasing particle size and increasing volumetric concentration. Solid shape particle and increasing dispersing fluid viscosity resulted in higher nanofluid viscosity. The higher the nanofluid concentration, the higher the oil recovery obtained. It can be concluded that nanofluid properties have been significantly affected by the environment and the particle used for potential EOR application.

  17. Enhancement of insulating properties of brick clay by renewable agricultural wastes

    Directory of Open Access Journals (Sweden)

    Viktor Bánhidi

    2008-12-01

    Full Text Available The use of agricultural wastes (byproducts in various segments of brick and tile industry is increasing continuously. These additives, which are previously mixed into the raw or compound clay, start to ignite during the firing process, providing extra thermal energy inside the product and decreasing the required external energy need. Besides this effect, the combustion of additives increases the porosity of the final product resulting in enhanced thermal insulation properties. In this paper the effect of some common agricultural wastes (sawdust, rice-peel and seed-shell on the thermal properties of brick clay products was investigated. The brick samples were prepared from the mixture of the yellow and gray clay in the ratio of 4:1, water content was between 15.57-16.67 wt.% and the pore-forming additives in concentrations 0, 4 and 7 wt.%. To measure the steady state thermal conductivity of the clay mixtures, samples with dimensions of 300×300×50 mm were prepared. Drying and firing were performed using the industrial partner’s standard procedures. Precise thermal conductivity data was measured, using a RAPID‑K type static thermal conductivity instrument. The results showed that increasing the quantity of agricultural byproducts in the clay mixture significantly decreases the thermal conductivity of the final products, while only a minor reduction in the mechanical strength was observed. It was found that the most efficient byproduct additive was the sunflower seed‑shell. With the addition of only 7 wt.% seed‑shell to the basic clay the thermal conductivity decreased from 0,27 W/m·K to 0,17 W/m·K (i.e. ~36%.

  18. Using The Corngrass1 Gene To Enhance The Biofuel Properties Of Crop Plants

    Energy Technology Data Exchange (ETDEWEB)

    Hake, Sarah [USDA Agricultural Research Service, Washington DC (United States); Chuck, George [USDA Agricultural Research Service, Washington DC (United States)

    2015-10-29

    The development of novel plant germplasm is vital to addressing our increasing bioenergy demands. The major hurdle to digesting plant biomass is the complex structure of the cell walls, the substrate of fermentation. Plant cell walls are inaccessible matrices of macromolecules that are polymerized with lignin, making fermentation difficult. Overcoming this hurdle is a major goal toward developing usable bioenergy crop plants. Our project seeks to enhance the biofuel properties of perennial grass species using the Corngrass1 (Cg1) gene and its targets. Dominant maize Cg1 mutants produce increased biomass by continuously initiating extra axillary meristems and leaves. We cloned Cg1 and showed that its phenotype is caused by over expression of a unique miR156 microRNA gene that negatively regulates SPL transcription factors. We transferred the Cg1 phenotype to other plants by expressing the gene behind constitutive promoters in four different species, including the monocots, Brachypodium and switchgrass, and dicots, Arabidopsis and poplar. All transformants displayed a similar range of phenotypes, including increased biomass from extended leaf production, and increased vegetative branching. Field grown switchgrass transformants showed that overall lignin content was reduced, the ratio of glucans to xylans was increased, and surprisingly, that starch levels were greatly increased. The goals of this project are to control the tissue and temporal expression of Cg1 by using different promoters to drive its expression, elucidate the function of the SPL targets of Cg1 by generating gain and loss of function alleles, and isolate downstream targets of select SPL genes using deep sequencing and chromatin immunoprecipitation. We believe it is possible to control biomass accumulation, cell wall properties, and sugar levels through manipulation of either the Cg1 gene and/or its SPL targets.

  19. Enhancement of antibacterial properties of polyurethanes by chitosan and heparin immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Kara, Filiz [Department of Chemistry, Faculty of Science, Gazi University, 06500 Ankara (Turkey); Aksoy, E. Ayse [Department of Basic Pharmaceutical Sciences, Faculty of Pharmacy, Hacettepe University, 06100 Ankara (Turkey); Yuksekdag, Zehranur [Biotechnology Laboratory, Department of Biology, Faculty of Science, Gazi University, 06500 Ankara (Turkey); Aksoy, Serpil [Department of Chemistry, Faculty of Science, Gazi University, 06500 Ankara (Turkey); Hasirci, Nesrin, E-mail: nhasirci@metu.edu.tr [BIOMATEN, Center of Excellence in Biomaterials and Tissue Engineering, Middle East Technical University, 06800 Ankara (Turkey); Department of Chemistry, Faculty of Arts and Sciences, Middle East Technical University, 06800 Ankara (Turkey)

    2015-12-01

    Graphical abstract: - Highlights: • Polyurethane elastomer was synthesized in medical purity. • Chitosan (CH) and heparin (Hep) were immobilized on polyurethane films. • Modification with CH and Hep increased hydrophilicity and surface free energy. • Immobilized films had high antibacterial activity against four bacteria. • Bacterial adhesion significantly decreased on the modified surfaces. - Abstract: Being antibacterial is a required property for the materials used in medical devices and instruments. Polyurethanes (PUs) are one class of polymers widely used in the production of devices that especially come in contact with blood (e.g. heart valves, blood vessels, vascular grafts and catheters). In this study, hexamethylene diisocyanate based polyurethanes (PUh) were synthesized and antibacterial and anti-adhesive properties were added by immobilizing chitosan (CH) and heparin (Hep) on the samples of PUh via a stepwise process. Chemistry and topography of the modified film samples (PUh-CH and PUh-CH-Hep) were examined by Fourier Transform Infrared Spectrophotometry-Attenuated Total Reflectance (FTIR-ATR), Electron Spectroscopy for Chemical Analysis (ESCA) and Atomic Force Microscopy (AFM), and surface free energy (SFE) values after each step were determined by goniometer. PUh-CH and PUh-CH-Hep samples were found to be antibacterial against Staphylococcus aureus (S. aureus) and Staphylococcus epidermidis (S. epidermidis) (both Gram positive) and Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) (both Gram negative) bacteria, and bacterial adhesion results showed a significant decrease in the number of viable bacteria on both modified samples where PUh-CH-Hep was the most effective. The findings of this study show that polymeric surfaces can be effectively modified and converted to be antibacterial by chitosan and heparin immobilization, and presence of both chemicals enhance efficacy against bacteria.

  20. Enhanced mechanical properties of thermosensitive chitosan hydrogel by silk fibers for cartilage tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Mirahmadi, Fereshteh [Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); National Cell Bank of Iran, Pasteur Institute of Iran, Tehran (Iran, Islamic Republic of); Tafazzoli-Shadpour, Mohammad, E-mail: Tafazoli@aut.ac.ir [Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Shokrgozar, Mohammad Ali, E-mail: mashokrgozar@pasteur.ac.ir [National Cell Bank of Iran, Pasteur Institute of Iran, Tehran (Iran, Islamic Republic of); Bonakdar, Shahin [National Cell Bank of Iran, Pasteur Institute of Iran, Tehran (Iran, Islamic Republic of)

    2013-12-01

    Articular cartilage has limited repair capability following traumatic injuries and current methods of treatment remain inefficient. Reconstructing cartilage provides a new way for cartilage repair and natural polymers are often used as scaffold because of their biocompatibility and biofunctionality. In this study, we added degummed chopped silk fibers and electrospun silk fibers to the thermosensitive chitosan/glycerophosphate hydrogels to reinforce two hydrogel constructs which were used as scaffold for hyaline cartilage regeneration. The gelation temperature and gelation time of hydrogel were analyzed by the rheometer and vial tilting method. Mechanical characterization was measured by uniaxial compression, indentation and dynamic mechanical analysis assay. Chondrocytes were then harvested from the knee joint of the New Zealand white rabbits and cultured in constructs. The cell proliferation, viability, production of glycosaminoglycans and collagen type II were assessed. The results showed that mechanical properties of the hydrogel were significantly enhanced when a hybrid with two layers of electrospun silk fibers was made. The results of GAG and collagen type II in cell-seeded scaffolds indicate support of the chondrogenic phenotype for chondrocytes with a significant increase in degummed silk fiber–hydrogel composite for GAG content and in two-layer electrospun fiber–hydrogel composite for Col II. It was concluded that these two modified scaffolds could be employed for cartilage tissue engineering. - Highlights: • Chitosan hydrogel composites fabricated by two forms of silk fiber • Silk fibers provide structural support for the hydrogel matrix. • The mechanical properties of hydrogel significantly improved by associating with silk. • Production of GAG and collagen type II was demonstrated within the scaffolds.

  1. Enhanced mechanical properties and increased corrosion resistance of a biodegradable magnesium alloy by plasma electrolytic oxidation (PEO).

    Science.gov (United States)

    White, Leon; Koo, Youngmi; Neralla, Sudheer; Sankar, Jagannathan; Yun, Yeoheung

    2016-06-01

    We report the enhanced mechanical properties of AZ31 magnesium alloys by plasma electrolytic oxidation (PEO) coating in NaOH, Na 2 SiO 3 , KF and NaH 2 PO 4 ·2H 2 O containing electrolytes. Mechanical properties including wear resistance, surface hardness and elastic modulus were increased for PEO-coated AZ31 Mg alloys (PEO-AZ31). DC polarization in Hank's solution indicating that the corrosion resistance significantly increased for PEO-coating in KF-contained electrolyte. Based on these results, the PEO coating method shows promising potential for use in biodegradable implant applications where tunable corrosion and mechanical properties are needed.

  2. Strontium-doped calcium silicate bioceramic with enhanced in vitro osteogenic properties.

    Science.gov (United States)

    No, Young Jung; Roohaniesfahani, Seyediman; Lu, Zufu; Shi, Jeffrey; Zreiqat, Hala

    2017-06-05

    Gehlenite (GLN, Ca 2 SiAl 2 O 7 ) is a bioceramic that has been recently shown to possess excellent mechanical strength and in vitro osteogenic properties for bone regeneration. Substitutional incorporation of strontium in place of calcium is an effective way to further enhance biological properties of calcium-based bioceramics and glasses. However, such strategy has the potential to affect other important physicochemical parameters such as strength and degradation due to differences in the ionic radius of strontium and calcium. This study is the first to investigate the effect of a range of concentrations of strontium substitution of calcium at 1, 2, 5, 10 mol% (S1-GLN, S2-GLN, S5-GLN and S10-GLN) on the physicochemical and biological properties of GLN. We showed that up to 2 mol% strontium ion substitution retains the monophasic GLN structure when sintered at 1450 °C, whereas higher concentrations resulted in presence of calcium silicate impurities. Increased strontium incorporation resulted in changes in grain morphology and reduced densification when the ceramics were sintered at 1450 °C. Porous GLN, S1-GLN and S2-GLN scaffolds (∼80% porosity) showed compressive strengths of 2.05 ± 0.46 MPa, 1.76 ± 0.79 MPa and 1.57 ± 0.52 MPa respectively. S1-GLN and S2-GLN immersed in simulated body fluid showed increased strontium ion release but reduced calcium and silicon ion release compared to GLN without affecting overall weight loss and pH over a 21 d period. The bioactivity of the S2-GLN ceramics was significantly improved as reflected in the significant upregulation of HOB proliferation and differentiation compared to GLN. Overall, these results suggest that increased incorporation of strontium presents a trade-off between bioactivity and mechanical strength for GLN bioceramics. This is an important consideration in the development of strontium-doped bioceramics.

  3. Chemical composition, antioxidant, anti-inflammatory and anti-proliferative activities of essential oils of plants from Burkina Faso.

    Directory of Open Access Journals (Sweden)

    Bagora Bayala

    Full Text Available This research highlights the chemical composition, antioxidant, anti-inflammatory and anti-proliferative activities of essential oils from leaves of Ocimum basilicum, Ocimum americanum, Hyptis spicigera, Lippia multiflora, Ageratum conyzoides, Eucalyptus camaldulensis and Zingiber officinale. Essential oils were analyzed by gas chromatography-mass spectrometry and gas chromatography-flame ionization detector. Major constituents were α-terpineol (59.78% and β-caryophyllene (10.54% for Ocimum basilicum; 1, 8-cineol (31.22%, camphor (12.730%, α-pinene (6.87% and trans α-bergamotene (5.32% for Ocimum americanum; β-caryophyllene (21%, α-pinene (20.11%, sabinene (10.26%, β-pinene (9.22% and α-phellandrene (7.03% for Hyptis spicigera; p-cymene (25.27%, β-caryophyllene (12.70%, thymol (11.88, γ-terpinene (9.17% and thymyle acetate (7.64% for Lippia multiflora; precocene (82.10%for Ageratum conyzoides; eucalyptol (59.55%, α-pinene (9.17% and limonene (8.76% for Eucalyptus camaldulensis; arcurcumene (16.67%, camphene (12.70%, zingiberene (8.40%, β-bisabolene (7.83% and β-sesquiphellandrène (5.34% for Zingiber officinale. Antioxidant activities were examined using 1,1-diphenyl-2-picryl-hydrazyl (DPPH and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS methods. O. basilicum and L. multiflora exhibited the highest antioxidant activity in DPPH and ABTS tests, respectively. Anti-inflammatory properties were evaluated by measuring the inhibition of lipoxygenase activity and essential oil of Z. officinale was the most active. Anti-proliferative effect was assayed by the measurement of MTT on LNCaP and PC-3 prostate cancer cell lines, and SF-763 and SF-767 glioblastoma cell lines. Essential oils from A. conyzoides and L. multiflora were the most active on LNCaP and PC-3 cell lines, respectively. The SF-767 glioblastoma cell line was the most sensitive to O. basilicum and L. multiflora EOs while essential oil of A. conyzoides showed the

  4. Enhancing the mechanical properties of electrospun polyester mats by heat treatment

    Directory of Open Access Journals (Sweden)

    M. Kancheva

    2015-01-01

    Full Text Available Microfibrous materials with a targeted design based on poly(L-lactic acid (PLA and poly(ε-caprolactone (PCL were prepared by electrospinning and by combining electrospinning and electrospraying. Several approaches were used: (i electrospinning of a common solution of the two polymers, (ii simultaneous electrospinning of two separate solutions of PLA and PCL, (iii electrospinning of PLA solution in conjunction with electrospraying of PCL solution, and (iv alternating layer-by-layer deposition by electrospinning of separate PLA and PCL solutions. The mats were heated at the melting temperature of PCL (60°", thus achieving melting of PCL fibers/particles and thermal sealing of the fibers. The mats subjected to thermal treatment were characterized by greater mean fiber diameters and reduced values of the water contact angle compared to the pristine mats. Heat treatment of the mats affected their thermal stability and led to an increase in the crystallinity degree of PLA incorporated in the mats, whereas that of PCL was reduced. All mats were characterized by enhanced mechanical properties after thermal treatment as compared to the non-treated fibrous materials.

  5. Maghemite nanoparticles with enhanced magnetic properties: one-pot preparation and ultrastable dextran shell.

    Science.gov (United States)

    Di Corato, Riccardo; Aloisi, Alessandra; Rella, Simona; Greneche, Jean-Marc; Pugliese, Giammarino; Pellegrino, Teresa; Malitesta, Cosimino; Rinaldi, Rosaria

    2018-05-10

    In the field on nanomedicine, superparamagnetic nanoparticles are one of the most studied nanomaterials for theranostics. In this paper, a one-pot synthesis of magnetic nanoparticles is presented, with elevated control on particles size from 10 to 40 nm. The monitoring of vacuum level is here introduced as a crucial parameter for achieving a fine particle morphology. Magnetic properties of these nanoparticles are highly affected by disorders or mismatches in crystal structure. A prolonged oxidation step is applied to the obtained nanoparticles to transform the magnetic phases into a pure maghemite one, confirmed by a high resolution XPS analysis, by Mössbauer spectrometry and, indirectly, by increased performances in magnetization curves and in relaxation times. Afterward, the attained nanoparticles are transferred in water by a non-derivatized dextran coating. The thermogravimetric analysis confirms that the polysaccharide molecules replace the oleic acid on the surface by stabilizing the particles in aqueous phase and culture media. Preliminary in vitro test reveals as the dextran coated nanoparticles are not passively internalized from the cells. As proof of concept, a secondary layer of chitosan assures a positive charge to the nanoparticle surface, thus enhancing the cellular internalization.

  6. Electrospun microcrimped fibers with nonlinear mechanical properties enhance ligament fibroblast phenotype.

    Science.gov (United States)

    Grace Chao, Pen-hsiu; Hsu, Hsiang-Yi; Tseng, Hsiao-Yun

    2014-09-01

    Fiber structure and order greatly impact the mechanical behavior of fibrous materials. In biological tissues, the nonlinear mechanics of fibrous scaffolds contribute to the functionality of the material. The nonlinear mechanical properties of the wavy structure (crimp) in collagen allow tissue flexibility while preventing over-extension. A number of approaches have tried to recreate this complex mechanical functionality. We generated microcrimped fibers by briefly heating electrospun parallel fibers over the glass transition temperature or by ethanol treatment. The crimp structure is similar to those of collagen fibers found in native aorta, intestines, or ligaments. Using poly-L-lactic acid fibers, we demonstrated that the bulk materials exhibit changed stress-strain behaviors with a significant increase in the toe region in correlation to the degree of crimp, similar to those observed in collagenous tissues. In addition to mimicking the stress-strain behavior of biological tissues, the microcrimped fibers are instructive in cell morphology and promote ligament phenotypic gene expression. This effect can be further enhanced by dynamic tensile loading, a physiological perturbation in vivo. This rapid and economical approach for microcrimped fiber production provides an accessible platform to study structure-function relationships and a novel functional scaffold for tissue engineering and cell mechanobiology studies.

  7. Environmental Synthesis of Few Layers Graphene Sheets Using Ultrasonic Exfoliation with Enhanced Electrical and Thermal Properties.

    Directory of Open Access Journals (Sweden)

    Monir Noroozi

    Full Text Available In this paper, we report how few layers graphene that can be produced in large quantity with low defect ratio from exfoliation of graphite by using a high intensity probe sonication in water containing liquid hand soap and PVP. It was founded that the graphene powder obtained by this simple exfoliation method after the heat treatment had an excellent exfoliation into a single or layered graphene sheets. The UV-visible spectroscopy, FESEM, TEM, X-ray powder diffraction and Raman spectroscopy was used to analyse the graphene product. The thermal diffusivity of the samples was analysed using a highly accurate thermal-wave cavity photothermal technique. The data obtained showed excellent enhancement in the thermal diffusivity of the graphene dispersion. This well-dispersed graphene was then used to fabricate an electrically conductive polymer-graphene film composite. The results demonstrated that this low cost and environmental friendly technique allowed to the production of high quality layered graphene sheets, improved the thermal and electrical properties. This may find use in the wide range of applications based on graphene.

  8. Cyclization Reaction of Acyl Thiourea Chitosan: Enhanced Antifungal Properties via Structural Optimization.

    Science.gov (United States)

    Qin, Yukun; Liu, Weixiang; Xing, Ronge; Liu, Song; Li, Kecheng; Li, Pengcheng

    2018-03-06

    In this study, 3-methyl-1,2,4-triazolyl chitosan (MTACS) and 3-chloromethyl-1,2,4-triazolyl chitosan (CMTACS) were prepared via cyclization of acyl thiourea chitosan (TUCS). Their structures were confirmed by FT-IR, ¹H-NMR, elemental analysis, DSC, XRD, and SEM. The conformations were predicted using the Gaussian 09 program. Additionally, the antifungal properties of MTACS and CMTACS against Stemphylium solani weber ( S. solani ), Alternaria porri ( A. porri ), and Gloeosporium theae-sinensis ( G. theae-sinensis ) were assayed in vitro and ranged from 250 μg/mL to 1000 μg/mL. The results showed that MTACS and CMTACS exhibited enhanced inhibitory effect on the selected fungi compared to the original chitosan and TUCS. In particular, they displayed better antifungal activities against A. porri and G. theae-sinensis than that of the positive control, Triadimefon. The findings described here may lead to them being used as antifungal agents for crop protection.

  9. Cyclization Reaction of Acyl Thiourea Chitosan: Enhanced Antifungal Properties via Structural Optimization

    Directory of Open Access Journals (Sweden)

    Yukun Qin

    2018-03-01

    Full Text Available In this study, 3-methyl-1,2,4-triazolyl chitosan (MTACS and 3-chloromethyl-1,2,4-triazolyl chitosan (CMTACS were prepared via cyclization of acyl thiourea chitosan (TUCS. Their structures were confirmed by FT-IR, 1H-NMR, elemental analysis, DSC, XRD, and SEM. The conformations were predicted using the Gaussian 09 program. Additionally, the antifungal properties of MTACS and CMTACS against Stemphylium solani weber (S. solani, Alternaria porri (A. porri, and Gloeosporium theae-sinensis (G. theae-sinensis were assayed in vitro and ranged from 250 μg/mL to 1000 μg/mL. The results showed that MTACS and CMTACS exhibited enhanced inhibitory effect on the selected fungi compared to the original chitosan and TUCS. In particular, they displayed better antifungal activities against A. porri and G. theae-sinensis than that of the positive control, Triadimefon. The findings described here may lead to them being used as antifungal agents for crop protection.

  10. Electrospun microcrimped fibers with nonlinear mechanical properties enhance ligament fibroblast phenotype

    International Nuclear Information System (INIS)

    Grace Chao, Pen-hsiu; Hsu, Hsiang-Yi; Tseng, Hsiao-Yun

    2014-01-01

    Fiber structure and order greatly impact the mechanical behavior of fibrous materials. In biological tissues, the nonlinear mechanics of fibrous scaffolds contribute to the functionality of the material. The nonlinear mechanical properties of the wavy structure (crimp) in collagen allow tissue flexibility while preventing over-extension. A number of approaches have tried to recreate this complex mechanical functionality. We generated microcrimped fibers by briefly heating electrospun parallel fibers over the glass transition temperature or by ethanol treatment. The crimp structure is similar to those of collagen fibers found in native aorta, intestines, or ligaments. Using poly-L-lactic acid fibers, we demonstrated that the bulk materials exhibit changed stress–strain behaviors with a significant increase in the toe region in correlation to the degree of crimp, similar to those observed in collagenous tissues. In addition to mimicking the stress–strain behavior of biological tissues, the microcrimped fibers are instructive in cell morphology and promote ligament phenotypic gene expression. This effect can be further enhanced by dynamic tensile loading, a physiological perturbation in vivo. This rapid and economical approach for microcrimped fiber production provides an accessible platform to study structure–function relationships and a novel functional scaffold for tissue engineering and cell mechanobiology studies. (papers)

  11. Green Route Fabrication of Graphene Oxide Reinforced Polymer Composites with Enhanced Mechanical Properties

    International Nuclear Information System (INIS)

    Mahendran, R.; Sridharan, D.; Santhakumar, K.; Gnanasekaran, G.

    2016-01-01

    A facile and “Green” route has been applied to fabricate graphene oxide (GO) reinforced polymer composites utilizing “deionized water” as solvent. The GO was reinforced into water soluble poly(vinyl alcohol) (PVA) and poly-2-acrylamido-2-methyl-1-propanesulfonic acid (PAMPS) matrix by ultrasonication followed by mechanical stirring. The incorporation and dispersion of the GO in the polymer matrix were analyzed by XRD, FE-SEM, AFM, FT-IR, and TGA. Further, the FE-SEM and AFM images revealed that the surface roughness and agglomeration of the GO in the polymer matrix increased by increasing its concentration. Ionic exchange capacity, proton conductivity, and tensile texture results showed that the reinforcement of GO in the polymer matrix enhances the physicochemical properties of the host polymer. These PVA/PAMPS/GO nano composites showed improved mechanical stability compared to the pristine polymer, because of strong interfacial interactions within the components and homogeneous dispersion of the GO sheets in the PVA/PAMPS matrix.

  12. Enhanced Photocatalytic Properties of Ag-Loaded N-Doped Tio2 Nanotube Arrays

    Directory of Open Access Journals (Sweden)

    Gao Dawei

    2018-03-01

    Full Text Available Highly ordered TiO2 nanotube (TiO2 NT arrays were prepared by anodic oxidizing method on the surface of the Ti substrate. Nitrogen-doped TiO2 nanotube (N-TiO2 NT arrays were carried out by ammonia solution immersion, and Ag nanoparticles loaded N-doped TiO2 nanotube (Ag/N-TiO2 NT arrays were obtained by successive ionic layer adsorption and reaction (SILAR technique. The samples were characterized by the X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, field emission scanning electron microscopy (FESEM, high-resolution transmission electron microscopy (HRTEM, photoluminescence (PL emission spectra, ultraviolet–visible (UV–vis diffuse reflectance spectroscopy (DRS. The result indicated that the diameter and wall thickness of the TiO2 NT are 100–120 and 20–30 nm, respectively. Moreover, the morphology and structure of the highly ordered TiO2 NTs were not affected by N-doping. Furthermore, Ag nanoparticles were evenly deposited on the surface of TiO2 NTs in the form of elemental silver. Finally, the photocatalytic activity of Ag/N-TiO2 NTs was evaluated by degradation of methyl orange (MO under visible-light irradiation. The Ag/N-TiO2 NTs exhibited enhanced photocatalytic properties, which could reach 95% after 90-min irradiation.

  13. Enhanced piezoelectric properties of vertically aligned single-crystalline NKN nano-rod arrays.

    Science.gov (United States)

    Kang, Min-Gyu; Oh, Seung-Min; Jung, Woo-Suk; Moon, Hi Gyu; Baek, Seung-Hyub; Nahm, Sahn; Yoon, Seok-Jin; Kang, Chong-Yun

    2015-05-08

    Piezoelectric materials capable of converting between mechanical and electrical energy have a great range of potential applications in micro- and nano-scale smart devices; however, their performance tends to be greatly degraded when reduced to a thin film due to the large clamping force by the substrate and surrounding materials. Herein, we report an effective method for synthesizing isolated piezoelectric nano-materials as means to relax the clamping force and recover original piezoelectric properties of the materials. Using this, environmentally friendly single-crystalline NaxK1-xNbO3 (NKN) piezoelectric nano-rod arrays were successfully synthesized by conventional pulsed-laser deposition and demonstrated to have a remarkably enhanced piezoelectric performance. The shape of the nano-structure was also found to be easily manipulated by varying the energy conditions of the physical vapor. We anticipate that this work will provide a way to produce piezoelectric micro- and nano-devices suitable for practical application, and in doing so, open a new path for the development of complex metal-oxide nano-structures.

  14. Enhanced microwave absorption properties of graphite nanoflakes by coating hexagonal boron nitride nanocrystals

    KAUST Repository

    Zhong, Bo; Liu, Wei; Yu, Yuanlie; Xia, Long; Zhang, Jiulin; Chai, Zhenfei; Wen, Guangwu

    2017-01-01

    We report herein the synthesis of a novel hexagonal boron nitride nanocrystal/graphite nanoflake (h-BNNC/GNF) composite through a wet-chemistry coating of graphite nanoflakes and subsequent in-situ thermal treatment process. The characterization results of X-ray diffraction, scanning electron microscope, transmission electron microscope, energy dispersive X-ray spectrum, and X-ray photoelectron spectroscopy demonstrate that h-BNNCs with diameter of tens of nanometers are highly crystallized and anchored on the surfaces of graphite nanoflakes without obvious aggregation. The minimum reflection loss (RL) value of the h-BNNC/GNF based absorbers could reach −32.38dB (>99.99% attenuation) with the absorber thickness of 2.0mm. This result is superior to the other graphite based and some dielectric loss microwave absorption materials recently reported. Moreover, the frequency range where the RL is less than −10dB is 3.49-17.28GHz with the corresponding thickness of 5.0 to 1.5mm. This reveals a better electromagnetic microwave absorption performance of h-BNNC/GNFs from the X-band to the Ku-band. The remarkable enhancement of the electromagnetic microwave absorption properties of h-BNNC/GNFs can be assigned to the increase of multiple scattering, interface polarization as well as the improvement of the electromagnetic impedance matching of graphite nanoflakes after being coated with h-BNNCs.

  15. Polyaniline/carbon nanotube/CdS quantum dot composites with enhanced optical and electrical properties

    Science.gov (United States)

    Goswami, Mrinmoy; Ghosh, Ranajit; Maruyama, Takahiro; Meikap, Ajit Kumar

    2016-02-01

    A new kind of polyaniline/carbon nanotube/CdS quantum dot composites have been developed via in-situ polymerization of aniline monomer in the presence of dispersed CdS quantum dots (size: 2.7-4.8 nm) and multi-walled carbon nanotubes (CNT), which exhibits enhanced optical and electrical properties. The existences of 1st order, 2nd order, and 3rd order longitudinal optical phonon modes, strongly indicate the high quality of synthesized CdS quantum dots. The occurrence of red shift of free exciton energy in photoluminescence is due to size dependent quantum confinement effect of CdS. The conductivity of the composites (for example PANI/CNT/CdS (2 wt.% CdS)) is increased by about 7 of magnitude compared to that of pure PANI indicating a charge transfer between CNT and polymer via CdS quantum dots. This advanced material has a great potential for high-performance of electro-optical applications.

  16. Enhanced microwave absorption properties of graphite nanoflakes by coating hexagonal boron nitride nanocrystals

    KAUST Repository

    Zhong, Bo

    2017-05-31

    We report herein the synthesis of a novel hexagonal boron nitride nanocrystal/graphite nanoflake (h-BNNC/GNF) composite through a wet-chemistry coating of graphite nanoflakes and subsequent in-situ thermal treatment process. The characterization results of X-ray diffraction, scanning electron microscope, transmission electron microscope, energy dispersive X-ray spectrum, and X-ray photoelectron spectroscopy demonstrate that h-BNNCs with diameter of tens of nanometers are highly crystallized and anchored on the surfaces of graphite nanoflakes without obvious aggregation. The minimum reflection loss (RL) value of the h-BNNC/GNF based absorbers could reach −32.38dB (>99.99% attenuation) with the absorber thickness of 2.0mm. This result is superior to the other graphite based and some dielectric loss microwave absorption materials recently reported. Moreover, the frequency range where the RL is less than −10dB is 3.49-17.28GHz with the corresponding thickness of 5.0 to 1.5mm. This reveals a better electromagnetic microwave absorption performance of h-BNNC/GNFs from the X-band to the Ku-band. The remarkable enhancement of the electromagnetic microwave absorption properties of h-BNNC/GNFs can be assigned to the increase of multiple scattering, interface polarization as well as the improvement of the electromagnetic impedance matching of graphite nanoflakes after being coated with h-BNNCs.

  17. Enhanced electrical and optical properties of CdS:Na thin films by photochemical deposition

    Science.gov (United States)

    Kumar, V. Nirmal; Suriakarthick, R.; Gopalakrishnan, R.; Hayakawa, Y.

    2017-06-01

    CdS:Na thin film was deposited on a glass substrate by photochemical deposition from aqueous solution contained CdSO4.5H2O and Na2S2O3 as cation and anion sources, respectively. The anion source Na2S2O3 served as Na dopant source. The deposited film exhibited cubic phase of CdS and incorporation of Na was revealed from X-ray diffraction study. The incorporation of Na in CdS changed the surface morphology from spherical to nano rods. CdS:Na thin film showed blue shift in its absorption spectrum which was more desirable for transmitting higher energy photons (visible region) in thin film solar cells. The Raman analysis confirmed 1 LO and 2 LO process at 297 and 593 cm-1, respectively. The carrier concentration of CdS increased with the inclusion of Na and its resistivity value decreased. Both the electrical and optical properties of CdS were enhanced in CdS:Na thin films which was desirable as a window layer material for photovoltaic application.

  18. Enhanced mechanical properties of thermosensitive chitosan hydrogel by silk fibers for cartilage tissue engineering.

    Science.gov (United States)

    Mirahmadi, Fereshteh; Tafazzoli-Shadpour, Mohammad; Shokrgozar, Mohammad Ali; Bonakdar, Shahin

    2013-12-01

    Articular cartilage has limited repair capability following traumatic injuries and current methods of treatment remain inefficient. Reconstructing cartilage provides a new way for cartilage repair and natural polymers are often used as scaffold because of their biocompatibility and biofunctionality. In this study, we added degummed chopped silk fibers and electrospun silk fibers to the thermosensitive chitosan/glycerophosphate hydrogels to reinforce two hydrogel constructs which were used as scaffold for hyaline cartilage regeneration. The gelation temperature and gelation time of hydrogel were analyzed by the rheometer and vial tilting method. Mechanical characterization was measured by uniaxial compression, indentation and dynamic mechanical analysis assay. Chondrocytes were then harvested from the knee joint of the New Zealand white rabbits and cultured in constructs. The cell proliferation, viability, production of glycosaminoglycans and collagen type II were assessed. The results showed that mechanical properties of the hydrogel were significantly enhanced when a hybrid with two layers of electrospun silk fibers was made. The results of GAG and collagen type II in cell-seeded scaffolds indicate support of the chondrogenic phenotype for chondrocytes with a significant increase in degummed silk fiber-hydrogel composite for GAG content and in two-layer electrospun fiber-hydrogel composite for Col II. It was concluded that these two modified scaffolds could be employed for cartilage tissue engineering. © 2013.

  19. Enhanced visible light photocatalytic property of red phosphorus via surface roughening

    International Nuclear Information System (INIS)

    Li, Weibing; Yue, Jiguang; Hua, Fangxia; Feng, Chang; Bu, Yuyu; Chen, Zhuoyuan

    2015-01-01

    Highlights: • Photocatalytic RhB degradation of red phosphorus was studied for the first time. • Surface rough can increase the photocatalysis reaction active sites. • Surface rough red phosphorus possesses high photocatalytic performance. • Surface rough red phosphorus has high industrial application value. - Abstract: Red phosphorus with rough surface (SRP) was prepared by catalyst-assisted hydrothermal synthesis using Co 2+ catalyst. The photocatalytic Rhodamine B (RhB) degradation of red phosphorus (RP) and SRP was studied for the first time in this work. Rough surface can enhance the dye adsorption ability of RP. About 75% RhB was absorbed by SRP after 30-min adsorption in 100 ml RhB solution with concentration of 10 mg l −1 in dark. After only 10 min of illumination by visible light, more than 95% RhB was degraded, indicating that SRP has a great application potential in the area of photocatalysis. The photocatalytic RhB degradation properties of RP are much weaker than those of SRP. The increase of the number of the active sites for the photocatalytic reactions, the electron mobility and the lifetime of the photogenerated electrons cause the significant improvement of the photocatalytic performance of SRP based on the experimental results obtained

  20. OPTIMIZATION OF PROCESS PARAMETERS FOR ENHANCED MECHANICAL PROPERTIES OF POLYPROPYLENE TERNARY NANOCOMPOSITES

    Directory of Open Access Journals (Sweden)

    Oladipupo Olaosebikan Ogunleye

    2015-02-01

    Full Text Available Preparation of Polypropylene ternary nanocomposites (PPTN was accomplished by blending multiwall carbon nanotube (MWCNT in polypropylene/clay binary system using a melt intercalation method. The effects of MWCNT loadings (A, melting temperature (B and mixing speed (C were investigated and optimized using central composite design. The analysis of the fitted cubic model clearly indicated that A and B were the main factors influencing the tensile properties at a fixed value of C. However, the analysis of variance showed that the interactions between the process parameters, such as; AB, AC, AB2, A2B and ABC, were highly significant on both tensile strength and Young’s modulus enhancement, while no interaction is significant in all models considered for elongation. The established optimal conditions gave 0.17%, 165 °C, and 120 rpm for A, B and C, respectively. These conditions yielded a percentage increase of 57 and 63% for tensile strength and Young’s modulus respectively compared to the virgin Polypropylene used.

  1. Preparation and Properties of Polymer/Vermiculite Hybrid Superabsorbent Reinforced by Fiber for Enhanced Oil Recovery

    Directory of Open Access Journals (Sweden)

    Fayang Jin

    2014-01-01

    Full Text Available A series of polymer/clay hybrid superabsorbent composites (SACFs comprising acrylamide, acrylic acid, sodium 2-acrylamido-tetradecyl sulfonate, fiber, and vermiculite by in situ intercalation and exfoliated method was successfully synthesized. The structure of SACFs was characterized by IR, SXRD, and SEM measurements. Much notable absorbency for SACF-2 was observed compared to that for SACF-1 in the absence of hydrophobic group in the high cationic solution due to the alkyl carbon chain and sulfonic acid group of hydrophobic moistures protecting the cations from attacking the carboxylate groups. What is more, high temperature fiber which acts as bridge connection for the polymeric network structure enhanced both toughness and strength for SACF-4 in the harsh conditions. At the total dissolved substance of 212000 mg/L for Tarim Basin injected water and the temperature of 120°C, desired absorbency as well as water retaining property for SACF-4 was observed during the long period of thermal ageing. Core flooding experiments demonstrated that SACFs could migrate as amoeba in the porous medium and accumulated in the narrow channel to adjust injection profile, promoting the subsequent water diverting into the unswept zones. Finally, characteristic parameters for SACFs calculated from flooding experiment further confirmed these polymer/clay hybrid composites reinforced by fiber would have robust application in the mature oilfield for profile control.

  2. Hydrothermal synthesis of mesoporous metal oxide arrays with enhanced properties for electrochemical energy storage

    International Nuclear Information System (INIS)

    Xiao, Anguo; Zhou, Shibiao; Zuo, Chenggang; Zhuan, Yongbing; Ding, Xiang

    2015-01-01

    Highlights: • NiO mesoporous nanowall arrays are prepared via hydrothermal method. • Mesoporous nanowall arrays are favorable for fast ion/electron transfer. • NiO mesoporous nanowall arrays show good supercapacitor performance. - Abstract: Mesoporous nanowall NiO arrays are prepared by a facile hydrothermal synthesis method with a following annealing process. The NiO nanowall shows continuous mesopores ranging from 5 to 10 nm and grows vertically on the substrate forming a porous net-like structure with macropores of 20–300 nm. A plausible mechanism is proposed for the growth of mesoporous nanowall NiO arrays. As cathode material of pseudocapacitors, the as-prepared mesoporous nanowall NiO arrays show good pseudocapacitive performances with a high capacitance of 600 F g −1 at 2 A g −1 and impressive high-rate capability with a specific capacitance of 338 F g −1 at 40 A g −1 . In addition, the mesoporous nanowall NiO arrays possess good cycling stability. After 6000 cycles at 2 A g −1 , a high capacitance of 660 F g −1 is attained, and no obvious degradation is observed. The good electrochemical performance is attributed to its highly porous morphology, which provides large reaction surface and short ion diffusion paths, leading to enhanced electrochemical properties

  3. Isocyanate toughening of pCBT/organoclay nanocomposites with exfoliated structure and enhanced mechanical properties

    Directory of Open Access Journals (Sweden)

    T. Abt

    2014-12-01

    Full Text Available Cyclic butylene terephthalate (CBT® is an interesting matrix material for the preparation of nanocomposites due to its very low, water-like melt viscosity which favours clay exfoliation. Nevertheless, polymerized CBT (pCBT is inherently brittle. This paper reports the preparation of isocyanate-toughened nanocomposites made from CBT and organo-modified montmorillonite. The role of the organoclay as reinforcement and the polymeric isocyanate (PMDI as toughening agent on the properties of pCBT was studied. The organoclay increased the stiffness and strength by up to 20% whereas the PMDI improved the deformation behaviour. However, the PMDI did not affect the degree of clay dispersion or exfoliation and flocculated-intercalated structures were observed. The compatibility between the pCBT matrix and clay was further increased by preparing PMDI-tethered intercalated organoclay. The modified organoclay then exfoliated during ring-opening polymerization and yielded true pCBT/clay nanocomposites. This work demonstrates that reactive chain extension of CBT with a polyfunctional isocyanate is an effective method to obtain toughened pCBT nanocomposites. Moreover, isocyanates can enhance the compatibility between pCBT and nanofiller as well as the degree of exfoliation.

  4. Enhanced visible light photocatalytic property of red phosphorus via surface roughening

    Energy Technology Data Exchange (ETDEWEB)

    Li, Weibing, E-mail: lwbing@qust.edu.cn [School of Environment and Safety Engineering, Qingdao University of Science and Technology, 53 Zhengzhou Road, Qingdao 266042 (China); Yue, Jiguang; Hua, Fangxia; Feng, Chang [School of Environment and Safety Engineering, Qingdao University of Science and Technology, 53 Zhengzhou Road, Qingdao 266042 (China); Bu, Yuyu; Chen, Zhuoyuan [Key Laboratory of Marine Environmental Corrosion and Bio-fouling, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071 (China)

    2015-10-15

    Highlights: • Photocatalytic RhB degradation of red phosphorus was studied for the first time. • Surface rough can increase the photocatalysis reaction active sites. • Surface rough red phosphorus possesses high photocatalytic performance. • Surface rough red phosphorus has high industrial application value. - Abstract: Red phosphorus with rough surface (SRP) was prepared by catalyst-assisted hydrothermal synthesis using Co{sup 2+} catalyst. The photocatalytic Rhodamine B (RhB) degradation of red phosphorus (RP) and SRP was studied for the first time in this work. Rough surface can enhance the dye adsorption ability of RP. About 75% RhB was absorbed by SRP after 30-min adsorption in 100 ml RhB solution with concentration of 10 mg l{sup −1} in dark. After only 10 min of illumination by visible light, more than 95% RhB was degraded, indicating that SRP has a great application potential in the area of photocatalysis. The photocatalytic RhB degradation properties of RP are much weaker than those of SRP. The increase of the number of the active sites for the photocatalytic reactions, the electron mobility and the lifetime of the photogenerated electrons cause the significant improvement of the photocatalytic performance of SRP based on the experimental results obtained.

  5. Emergent Low-Symmetry Phases and Large Property Enhancements in Ferroelectric KNbO 3 Bulk Crystals

    Energy Technology Data Exchange (ETDEWEB)

    Lummen, Tom T. A. [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 USA; Leung, J. [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 USA; Kumar, Amit [School of Mathematics and Physics, Queen' s University Belfast, University Road, Belfast BT71NN Northern Ireland UK; Wu, X. [Department of Physics, University of Texas at Austin, Austin TX 78712 USA; Ren, Y. [Department of Physics, University of Texas at Austin, Austin TX 78712 USA; VanLeeuwen, Brian K. [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 USA; Haislmaier, Ryan C. [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 USA; Holt, Martin [Center for Nanoscale Materials, Argonne National Laboratory, Argonne IL 60439 USA; Lai, Keji [Department of Physics, University of Texas at Austin, Austin TX 78712 USA; Kalinin, Sergei V. [Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge TN 37831 USA; Gopalan, Venkatraman [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 USA

    2017-06-19

    The design of new or enhanced functionality in materials is traditionally viewed as requiring the discovery of new chemical compositions through synthesis. Large property enhancements may however also be hidden within already well-known materials, when their structural symmetry is deviated from equilibrium through a small local strain or field. Here, the discovery of enhanced material properties associated with a new metastable phase of monoclinic symmetry within bulk KNbO3 is reported. This phase is found to coexist with the nominal orthorhombic phase at room temperature, and is both induced by and stabilized with local strains generated by a network of ferroelectric domain walls. While the local microstructural shear strain involved is only approximate to 0.017%, the concurrent symmetry reduction results in an optical second harmonic generation response that is over 550% higher at room temperature. Moreover, the meandering walls of the low-symmetry domains also exhibit enhanced electrical conductivity on the order of 1 S m(-1). This discovery reveals a potential new route to local engineering of significant property enhancements and conductivity through symmetry lowering in ferroelectric crystals.

  6. Antiproliferative/cytotoxic effects of molecular iodine, povidone-iodine and Lugol's solution in different human carcinoma cell lines.

    Science.gov (United States)

    Rösner, Harald; Möller, Wolfgang; Groebner, Sabine; Torremante, Pompilio

    2016-09-01

    Clinical trials have revealed that molecular iodine (I 2 ) has beneficial effects in fibrocystic breast disease and in cyclic mastalgia. Likewise, povidone-iodine (PVP-I), which is widely used in clinical practice as an antiseptic agent following tumour surgery, has been demonstrated to have cytotoxic effects on colon cancer and ascites tumour cells. Our previous study indicated that the growth of breast cancer and seven other human malignant cell lines was variably diminished by I 2 and iodolactones. With the intention of developing an iodine-based anticancer therapy, the present investigations extended these studies by comparing the cytotoxic capacities of I 2 , potassium iodide (KJ), PVP-I and Lugol's solution on various human carcinoma cell lines. Upon staining the cell nuclei with Hoechst 33342, the cell densities were determined microscopically. While KJ alone did not affect cell proliferation, it enhanced the antiproliferative activity of I 2 . In addition, PVP-I significantly inhibited the proliferation of human MCF-7 breast carcinoma, IPC melanoma, and A549 and H1299 lung carcinoma cells in a concentration corresponding to 20 µM I 2 . Likewise, Lugol's solution in concentrations corresponding to 20-80 µM I 2 were observed to reduce the growth of MCF-7 cells. Experiments with fresh human blood samples revealed that the antiproliferative activity of PVP-I and I 2 is preserved in blood plasma to a high degree. These findings suggest that PVP-I, Lugol's solution, and a combination of iodide and I 2 may be potent agents for use in the development of antitumour strategies.

  7. Harnessing microbial subsurface metal reduction activities to synthesise nanoscale cobalt ferrite with enhanced magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Coker, Victoria S.; Telling, Neil D.; van der Laan, Gerrit; Pattrick, Richard A.D.; Pearce, Carolyn I.; Arenholz, Elke; Tuna, Floriana; Winpenny, Richard E.P.; Lloyd, Jonathan R.

    2009-03-24

    Nanoscale ferrimagnetic particles have a diverse range of uses from directed cancer therapy and drug delivery systems to magnetic recording media and transducers. Such applications require the production of monodisperse nanoparticles with well-controlled size, composition, and magnetic properties. To fabricate these materials purely using synthetic methods is costly in both environmental and economical terms. However, metal-reducing microorganisms offer an untapped resource to produce these materials. Here, the Fe(III)-reducing bacterium Geobacter sulfurreducens is used to synthesize magnetic iron oxide nanoparticles. A combination of electron microscopy, soft X-ray spectroscopy, and magnetometry techniques was employed to show that this method of biosynthesis results in high yields of crystalline nanoparticles with a narrow size distribution and magnetic properties equal to the best chemically synthesized materials. In particular, it is demonstrated here that cobalt ferrite (CoFe{sub 2}O{sub 4}) nanoparticles with low temperature coercivity approaching 8 kOe and an effective anisotropy constant of {approx} 10{sup 6} erg cm{sup -3} can be manufactured through this biotechnological route. The dramatic enhancement in the magnetic properties of the nanoparticles by the introduction of high quantities of Co into the spinel structure represents a significant advance over previous biomineralization studies in this area using magnetotactic bacteria. The successful production of nanoparticulate ferrites achieved in this study at high yields could open up the way for the scaled-up industrial manufacture of nanoparticles using environmentally benign methodologies. Production of ferromagnetic nanoparticles for pioneering cancer therapy, drug delivery, chemical sensors, catalytic activity, photoconductive materials, as well as more traditional uses in data storage embodies a large area of inorganic synthesis research. In particular, the addition of transition metals other than

  8. Harnessing microbial subsurface metal reduction activities to synthesize nanoscale cobalt ferrite with enhanced magnetic properties

    International Nuclear Information System (INIS)

    Coker, Victoria S.; Telling, Neil D.; van der Laan, Gerrit; Pattrick, Richard A.D.; Pearce, Carolyn I.; Arenholz, Elke; Tuna, Floriana; Winpenny, Richard E.P.; Lloyd, Jonathan R.

    2009-01-01

    Nanoscale ferrimagnetic particles have a diverse range of uses from directed cancer therapy and drug delivery systems to magnetic recording media and transducers. Such applications require the production of monodisperse nanoparticles with well-controlled size, composition, and magnetic properties. To fabricate these materials purely using synthetic methods is costly in both environmental and economical terms. However, metal-reducing microorganisms offer an untapped resource to produce these materials. Here, the Fe(III)-reducing bacterium Geobacter sulfurreducens is used to synthesize magnetic iron oxide nanoparticles. A combination of electron microscopy, soft X-ray spectroscopy, and magnetometry techniques was employed to show that this method of biosynthesis results in high yields of crystalline nanoparticles with a narrow size distribution and magnetic properties equal to the best chemically synthesized materials. In particular, it is demonstrated here that cobalt ferrite (CoFe 2 O 4 ) nanoparticles with low temperature coercivity approaching 8 kOe and an effective anisotropy constant of ∼ 10 6 erg cm -3 can be manufactured through this biotechnological route. The dramatic enhancement in the magnetic properties of the nanoparticles by the introduction of high quantities of Co into the spinel structure represents a significant advance over previous biomineralization studies in this area using magnetotactic bacteria. The successful production of nanoparticulate ferrites achieved in this study at high yields could open up the way for the scaled-up industrial manufacture of nanoparticles using environmentally benign methodologies. Production of ferromagnetic nanoparticles for pioneering cancer therapy, drug delivery, chemical sensors, catalytic activity, photoconductive materials, as well as more traditional uses in data storage embodies a large area of inorganic synthesis research. In particular, the addition of transition metals other than Fe into the structure

  9. Antioxidative and antiproliferative activities of novel pyrido[1,2-a]benzimidazoles.

    Science.gov (United States)

    Tireli, Martina; Starčević, Kristina; Martinović, Tamara; Pavelić, Sandra Kraljević; Karminski-Zamola, Grace; Hranjec, Marijana

    2017-02-01

    A series of pyrido[1,2-a]benzimidazoles has been designed, and novel examples are synthesized and evaluated for their potential antiproliferative activity against four human tumour cell lines-cervical (HeLa), colorectal (SW620), breast (MCF-7) and hepatocellular carcinoma (HepG2). In addition, their antioxidative potency has been evaluated by in vitro spectrophotometric assays. Preliminary structure-activity relationships among the synthesized compounds are discussed. Evaluation of their antioxidative capacity has shown that two compounds (25 and 26) possess promising reducing characteristics and free radical scavenging activity. Selective antiproliferative effect in the single-digit micromolar range was observed for compound 25 on MCF-7 [Formula: see text] and HeLa [Formula: see text] cell lines, comparable to the standards 5-fluorouracil and cisplatin. The combination of the radical scavenging activity and antiproliferative activity of compound 25 positions this compound as a potential lead candidate for further optimization.

  10. Characterization of Metabolic, Diffusion, and Perfusion Properties in GBM: Contrast-Enhancing versus Non-Enhancing Tumor.

    Science.gov (United States)

    Autry, Adam; Phillips, Joanna J; Maleschlijski, Stojan; Roy, Ritu; Molinaro, Annette M; Chang, Susan M; Cha, Soonmee; Lupo, Janine M; Nelson, Sarah J

    2017-12-01

    Although the contrast-enhancing (CE) lesion on T 1 -weighted MR images is widely used as a surrogate for glioblastoma (GBM), there are also non-enhancing regions of infiltrative tumor within the T 2 -weighted lesion, which elude radiologic detection. Because non-enhancing GBM (Enh-) challenges clinical patient management as latent disease, this study sought to characterize ex vivo metabolic profiles from Enh- and CE GBM (Enh+) samples, alongside histological and in vivo MR parameters, to assist in defining criteria for estimating total tumor burden. Fifty-six patients with newly diagnosed GBM received a multi-parametric pre-surgical MR examination. Targets for obtaining image-guided tissue samples were defined based on in vivo parameters that were suspicious for tumor. The actual location from where tissue samples were obtained was recorded, and half of each sample was analyzed for histopathology while the other half was scanned using HR-MAS spectroscopy. The Enh+ and Enh- tumor samples demonstrated comparable mitotic activity, but also significant heterogeneity in microvascular morphology. Ex vivo spectroscopic parameters indicated similar levels of total choline and N-acetylaspartate between these contrast-based radiographic subtypes of GBM, and characteristic differences in the levels of myo-inositol, creatine/phosphocreatine, and phosphoethanolamine. Analysis of in vivo parameters at the sample locations were consistent with histological and ex vivo metabolic data. The similarity between ex vivo levels of choline and NAA, and between in vivo levels of choline, NAA and nADC in Enh+ and Enh- tumor, indicate that these parameters can be used in defining non-invasive metrics of total tumor burden for patients with GBM. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  11. Characterization of Metabolic, Diffusion, and Perfusion Properties in GBM: Contrast-Enhancing versus Non-Enhancing Tumor

    Directory of Open Access Journals (Sweden)

    Adam Autry

    2017-12-01

    Full Text Available BACKGROUND: Although the contrast-enhancing (CE lesion on T1-weighted MR images is widely used as a surrogate for glioblastoma (GBM, there are also non-enhancing regions of infiltrative tumor within the T2-weighted lesion, which elude radiologic detection. Because non-enhancing GBM (Enh− challenges clinical patient management as latent disease, this study sought to characterize ex vivo metabolic profiles from Enh− and CE GBM (Enh+ samples, alongside histological and in vivo MR parameters, to assist in defining criteria for estimating total tumor burden. Methods: Fifty-six patients with newly diagnosed GBM received a multi-parametric pre-surgical MR examination. Targets for obtaining image-guided tissue samples were defined based on in vivo parameters that were suspicious for tumor. The actual location from where tissue samples were obtained was recorded, and half of each sample was analyzed for histopathology while the other half was scanned using HR-MAS spectroscopy. Results: The Enh+ and Enh− tumor samples demonstrated comparable mitotic activity, but also significant heterogeneity in microvascular morphology. Ex vivo spectroscopic parameters indicated similar levels of total choline and N-acetylaspartate between these contrast-based radiographic subtypes of GBM, and characteristic differences in the levels of myo-inositol, creatine/phosphocreatine, and phosphoethanolamine. Analysis of in vivo parameters at the sample locations were consistent with histological and ex vivo metabolic data. CONCLUSIONS: The similarity between ex vivo levels of choline and NAA, and between in vivo levels of choline, NAA and nADC in Enh+ and Enh− tumor, indicate that these parameters can be used in defining non-invasive metrics of total tumor burden for patients with GBM.

  12. Antiproliferative activity of aqueous leaf extract of Annona muricata L. on the prostate, BPH-1 cells, and some target genes.

    Science.gov (United States)

    Asare, George Awuku; Afriyie, Dan; Ngala, Robert A; Abutiate, Harry; Doku, Derek; Mahmood, Seidu A; Rahman, Habibur

    2015-01-01

    Annona muricata L. has been reported to possess antitumor and antiproliferative properties. Not much work has been done on its effect on BPH-1 cell lines, and no in vivo studies targeting the prostate organ exist. The study determined the effect of A muricata on human BPH-1 cells and prostate organ. The MTT assay was performed on BPH-1 cells using the aqueous leaf extract of A muricata. Cells (1 × 10(5) per well) were challenged with 0.5, 1.0, and 1.5 mg/mL extract for 24, 48, and 72 hours. Cell proliferation and morphology were examined microscopically. BPH-1 cells (1 × 10(4) per well) were seeded into 6-well plates and incubated for 48 hours with 0.5, 1.0, and 1.5 mg/mL A muricata extract. Reverse transcriptase polymerase chain reaction was performed using mRNA extracted from the cells. Possible target genes, Bax and Bcl-2, were examined. Twenty F344 male rats (≈200 g) were gavaged 30 mg/mL (10 rats) and 300 mg/mL (10 rats) and fed ad libitum alongside 10 control rats. Rats were sacrificed after 60 days. The prostate, seminal vesicles, and testes were harvested for histological examination. Annona muricata demonstrated antiproliferative effects with an IC50 of 1.36 mg/mL. Best results were obtained after 48 hours, with near cell extinction at 72 hours. Bax gene was upregulated, while Bcl-2 was downregulated. Normal histological architecture was observed for all testes. Seminal vesicle was significantly reduced in test groups (P BPH-1 cells and reduces prostate size, possibly through apoptosis. © The Author(s) 2014.

  13. 14-Day thawed plasma retains clot enhancing properties and inhibits tPA-induced fibrinolysis.

    Science.gov (United States)

    Huebner, Benjamin R; Moore, Ernest E; Moore, Hunter B; Shepherd-Singh, Raymond; Sauaia, Angela; Stettler, Gregory R; Nunns, Geoffrey R; Silliman, Christopher C

    2017-11-01

    Plasma-first resuscitation attenuates trauma-induced coagulopathy (TIC); however, the logistics of plasma-first resuscitation require thawed plasma (TP) be readily available due to the obligatory thawing time of fresh frozen plasma (FFP). The current standard is storage of TP for up to 5 days at 4°C, based on factor levels at outdate, for use in patients at risk for TIC, but there remains a 2.2% outdated wastage rate. However, the multitude of plasma proteins in attenuating TIC remains unknown. We hypothesize that TP retains the ability to enhance clotting and reduce tPA-induced fibrinolysis at 14-day storage. FFP was thawed and stored at 4°C at the following intervals: 14, 10, 7, 5, 3, and 1-day prior to the experiment. Healthy volunteers underwent blood draws followed by 50% dilution with TP stored at previously mentioned intervals as well as FFP, normal saline (NS), albumin, and whole blood (WB) control. Samples underwent tPA-modified (75 ng/mL) thrombelastography (TEG) with analysis of R-time, angle, maximum amplitude (MA), and LY30. TEG properties did not change significantly over the thawed storage. 14-day TP retained the ability to inhibit tPA-induced hyperfibrinolysis (median LY30% 9.6%) similar to FFP (5.6%), WB (14.6%), and superior to albumin (59.3%) and NS (58.1%). 14-day TP also retained faster clot formation (median angle, 66.2°) and superior clot strength (MA, 61.5 mm) to albumin (34.8°, 21.6 mm) and NS (41.6°, 32.2 mm). TP plasma stored for 14 days retains clot-enhancing ability and resistance to clot degradation similar to FFP. A clinical trial is needed to validate these in vitro results. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Controllable synthesis and enhanced photocatalytic properties of Cu2O/Cu31S16 composites

    International Nuclear Information System (INIS)

    Liu, Xueqin; Li, Zhen; Zhang, Qiang; Li, Fei

    2012-01-01

    Highlights: ► Facile sonochemical route. ► The content of Cu 31 S 16 in the Cu 2 O/Cu 31 S 16 can be easily controlled. ► Structure and optical properties of Cu 2 O/Cu 31 S 16 were discussed. ► Enhanced photocatalytic property of Cu 2 O/Cu 31 S 16 . ► Cu 2 O/Cu 31 S 16 core/shell structures were more stable than single Cu 2 O particles. -- Abstract: The controlled synthesis of Cu 2 O/Cu 31 S 16 microcomposites with hierarchical structures had been prepared via a convenient sonochemical route. Ultrasonic irradiation of a mixture of Cu 2 O and (NH 2 ) 2 CS in an aqueous medium yielded Cu 2 O/Cu 31 S 16 composites. The content of Cu 31 S 16 in the Cu 2 O/Cu 31 S 16 can be easily controlled by adjusting the synthesis time. The Cu 31 S 16 layer not only protected and stabilized Cu 2 O particles, but also prohibited the recombination of photogenerated electrons–holes pair between Cu 31 S 16 and Cu 2 O. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) spectra, ultraviolet–visible (UV–Vis) spectroscopy and photoluminescence (PL) spectroscopy were used to characterize the products. Photocatalytic performance of the Cu 2 O/Cu 31 S 16 hierarchical structures was evaluated by measuring the decomposition rate of methyl orange solution under natural light. To the best of our knowledge, this is the first report on the preparation and photocatalytic activity of Cu 2 O/Cu 31 S 16 microcomposite. Additionally, the Cu 2 O/Cu 31 S 16 core/shell structures were more stable than single Cu 2 O particles during photocatalytic process since the photocatalytic activity of the second reused architecture sample was much higher than that of pure Cu 2 O. The Cu 2 O/Cu 31 S 16 microcomposites may be a good promising candidate for wastewater treatment.

  15. Conjugation of Benzylvanillin and Benzimidazole Structure Improves DNA Binding with Enhanced Antileukemic Properties

    Science.gov (United States)

    Al-Mudarris, Ban A.; Chen, Shih-Hsun; Liang, Po-Huang; Osman, Hasnah; Jamal Din, Shah Kamal Khan; Abdul Majid, Amin M. S.

    2013-01-01

    Benzyl-o-vanillin and benzimidazole nucleus serve as important pharmacophore in drug discovery. The benzyl vanillin (2-(benzyloxy)-3-methoxybenzaldehyde) compound shows anti-proliferative activity in HL60 leukemia cancer cells and can effect cell cycle progression at G2/M phase. Its apoptosis activity was due to disruption of mitochondrial functioning. In this study, we have studied a series of compounds consisting of benzyl vanillin and benzimidazole structures. We hypothesize that by fusing these two structures we can produce compounds that have better anticancer activity with improved specificity particularly towards the leukemia cell line. Here we explored the anticancer activity of three compounds namely 2-(2-benzyloxy-3-methoxyphenyl)-1H-benzimidazole, 2MP, N-1-(2-benzyloxy-3-methoxybenzyl)-2-(2-benzyloxy-3-methoxyphenyl)-1H-benzimidazole, 2XP, and (R) and (S)-1-(2-benzyloxy-3-methoxyphenyl)-2, 2, 2-trichloroethyl benzenesulfonate, 3BS and compared their activity to 2-benzyloxy-3-methoxybenzaldehyde, (Bn1), the parent compound. 2XP and 3BS induces cell death of U937 leukemic cell line through DNA fragmentation that lead to the intrinsic caspase 9 activation. DNA binding study primarily by the equilibrium binding titration assay followed by the Viscosity study reveal the DNA binding through groove region with intrinsic binding constant 7.39 µM/bp and 6.86 µM/bp for 3BS and 2XP respectively. 2XP and 3BS showed strong DNA binding activity by the UV titration method with the computational drug modeling showed that both 2XP and 3BS failed to form any electrostatic linkages except via hydrophobic interaction through the minor groove region of the nucleic acid. The benzylvanillin alone (Bn1) has weak anticancer activity even after it was combined with the benzimidazole (2MP), but after addition of another benzylvanillin structure (2XP), stronger activity was observed. Also, the combination of benzylvanillin with benzenesulfonate (3BS) significantly improved the

  16. Antioxidant and antiproliferative activities in different maturation stages of broccoli (Brassica oleracea Italica) biofortified with selenium.

    Science.gov (United States)

    Bachiega, Patricia; Salgado, Jocelem Mastrodi; de Carvalho, João Ernesto; Ruiz, Ana Lúcia T G; Schwarz, Kélin; Tezotto, Tiago; Morzelle, Maressa Caldeira

    2016-01-01

    In this work, three different broccoli maturity stages subjected to biofortification with selenium were evaluated for antioxidant and antiproliferative activities. Antioxidant trials have shown that the maturation stages biofortified with selenium had significantly higher amounts of phenolic compounds and antioxidant activity, especially seedlings. Although non-polar extracts of all samples show antiproliferative activity, the extract of broccoli seedlings biofortified with selenium stood out, presenting cytocidal activity for a glioma line (U251, GI50 28.5 mg L(-1)). Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Enhanced pyroelectric and piezoelectric properties of PZT with aligned porosity for energy harvesting applications.

    Science.gov (United States)

    Zhang, Yan; Xie, Mengying; Roscow, James; Bao, Yinxiang; Zhou, Kechao; Zhang, Dou; Bowen, Chris R

    2017-04-14

    This paper demonstrates the significant benefits of exploiting highly aligned porosity in piezoelectric and pyroelectric materials for improved energy harvesting performance. Porous lead zirconate (PZT) ceramics with aligned pore channels and varying fractions of porosity were manufactured in a water-based suspension using freeze-casting. The aligned porous PZT ceramics were characterized in detail for both piezoelectric and pyroelectric properties and their energy harvesting performance figures of merit were assessed parallel and perpendicular to the freezing direction. As a result of the introduction of porosity into the ceramic microstructure, high piezoelectric and pyroelectric harvesting figures of merits were achieved for porous freeze-cast PZT compared to dense PZT due to the reduced permittivity and volume specific heat capacity. Experimental results were compared to parallel and series analytical models with good agreement and the PZT with porosity aligned parallel to the freezing direction exhibited the highest piezoelectric and pyroelectric harvesting response; this was a result of the enhanced interconnectivity of the ferroelectric material along the poling direction and reduced fraction of unpoled material that leads to a higher polarization. A complete thermal energy harvesting system, composed of a parallel-aligned PZT harvester element and an AC/DC converter, was successfully demonstrated by charging a storage capacitor. The maximum energy density generated by the 60 vol% porous parallel-connected PZT when subjected to thermal oscillations was 1653 μJ cm -3 , which was 374% higher than that of the dense PZT with an energy density of 446 μJ cm -3 . The results are beneficial for the design and manufacture of high performance porous pyroelectric and piezoelectric materials in devices for energy harvesting and sensor applications.

  18. Aldehyde dehydrogenase (ALDH activity does not select for cells with enhanced aggressive properties in malignant melanoma.

    Directory of Open Access Journals (Sweden)

    Lina Prasmickaite

    Full Text Available BACKGROUND: Malignant melanoma is an exceptionally aggressive, drug-resistant and heterogeneous cancer. Recently it has been shown that melanoma cells with high clonogenic and tumourigenic abilities are common, but markers distinguishing such cells from cells lacking these abilities have not been identified. There is therefore no definite evidence that an exclusive cell subpopulation, i.e. cancer stem cells (CSC, exists in malignant melanoma. Rather, it is suggested that multiple cell populations are implicated in initiation and progression of the disease, making it of importance to identify subpopulations with elevated aggressive properties. METHODS AND FINDINGS: In several other cancer forms, Aldehyde Dehydrogenase (ALDH, which plays a role in stem cell biology and resistance, is a valuable functional marker for identification of cells that show enhanced aggressiveness and drug-resistance. Furthermore, the presence of ALDH(+ cells is linked to poor clinical prognosis in these cancers. By analyzing cell cultures, xenografts and patient biopsies, we showed that aggressive melanoma harboured a large, distinguishable ALDH(+ subpopulation. In vivo, ALDH(+ cells gave rise to ALDH(- cells, while the opposite conversion was rare, indicating a higher abilities of ALDH(+ cells to reestablish tumour heterogeneity with respect to the ALDH phenotype. However, both ALDH(+ and ALDH(- cells demonstrated similarly high abilities for clone formation in vitro and tumour initiation in vivo. Furthermore, both subpopulations showed similar sensitivity to the anti-melanoma drugs, dacarbazine and lexatumumab. CONCLUSIONS: These findings suggest that ALDH does not distinguish tumour-initiating and/or therapy-resistant cells, implying that the ALDH phenotype is not associated with more-aggressive subpopulations in malignant melanoma, and arguing against ALDH as a "universal" marker. Besides, it was shown that the ability to reestablish tumour heterogeneity is not

  19. Hepatobiliary contrast agents for contrast-enhanced MRI of the liver: properties, clinical development and applications

    International Nuclear Information System (INIS)

    Reimer, Peter; Schneider, Guenter; Schima, Wolfgang

    2004-01-01

    Hepatobiliary contrast agents with uptake into hepatocytes followed by variable biliary excretion represent a unique class of cell-specific MR contrast agents. Two hepatobiliary contrast agents, mangafodipir trisodium and gadobenate dimeglumine, are already clinically approved. A third hepatobiliary contrast agent, Gd-EOB-DTPA, is under consideration. The purpose of this review is to provide an overview on the properties, clinical development and application of these three hepatobiliary contrast agents. Bolus injectable paramagnetic hepatobiliary contrast agents combine established features of extracellular agents with the advantages of hepatocyte specificity. The detection and characterisation of focal liver disease appears to be improved compared to unenhanced MRI, MRI with unspecific contrast agents and contrast-enhanced CT. To decrease the total time spent by a patient in the MR scanner, it is advisable to administer the agent immediately after acquisition of unenhanced T1-w MRI. After infusion or bolus injection (with dynamic FS-T1-w 2D or 3D GRE) of the contrast agent, moderately and heavily T2w images are acquired. Post-contrast T1-w MRI is started upon completion of T2-w MRI for mangafodipir trisodium and Gd-EOB-DTPA as early as 20 min following injection, while gadobenate dimeglumine scans are obtained >60 min following injection. Post-contrast acquisition techniques with near isotropic 3D pulse sequences with fat saturation parallel the technical progress made by MSCT combined with an unparalleled improvement in tumour-liver contrast. The individual decision that hepatobiliary contrast agent one uses is partly based on personal preferences. No comparative studies have been conducted comparing the advantages or disadvantages of all three agents directly against each other. (orig.)

  20. Role of direct covalent bonding in enhanced heat dissipation property of flexible graphene oxide–carbon nanotube hybrid film

    International Nuclear Information System (INIS)

    Hwang, Yongseon; Kim, Myeongjin; Kim, Jooheon

    2013-01-01

    The thermal conductivity of graphene oxide/multiwalled carbon nanotube (GO/MWCNT) hybrid films with and without covalent bonding is examined in this study. To fabricate chemically bonded GO/MWCNT hybrid films, chlorinated GO and amino-functionalized MWCNTs are bonded covalently. The mixtures of surface modified GO and MWCNT were filtered and then subjected to hot pressing to fabricate stacked films. Examination of these chemically bonded hybrid films reveal that chlorine-doped GO exhibits enhanced electrical properties because it creates hole charge carriers by attracting the electrons in GO towards chlorine. Enhanced electrical conductivity and low sheet resistance are observed also with increasing MWCNT loadings. On comparing the through-plane thermal properties, the chemically bonded hybrid films were found to exhibit higher thermal conductivity than do the physically bonded hybrid films because of the synergetic interaction of functional groups in GO and MWCNTs in the former films. However, excess addition of MWCNTs to the films leads to an increasing phonon scattering density and a decreased thermal conductivity. - Highlights: • Graphene oxide/carbon nanotube (GO/CNT) films are bonded covalently. • GO/CNT hybrid films are prepared through filtering and hot-pressing method. • Chemically bonded hybrid films exhibit enhanced electrical and thermal properties. • Enhanced thermal conductivity is explained according to increasing CNT contents

  1. Synthesis, antimicrobial, and antiproliferative activities of substituted phenylfuranylnicotinamidines

    Directory of Open Access Journals (Sweden)

    Youssef MM

    2016-03-01

    cell (LC50 values. Structure-activity relationship studies demonstrated that the activity of members of this series can be modulated from cytostatic to cytotoxic based on the substitution pattern/nature on the terminal phenyl ring. The most active compound was found to be 4e displaying a submicromolar GI50 value of 0.83 µM, with TGI and LC50 values of 2.51 and 100 µM, respectively. Finally, the possible underlying mechanism of action of this series of compounds was investigated by determining their nuclease-like DNA degradation ability in addition to their antioxidant power and all monocations proved to be effective in all assays.Keywords: substituted phenylfuranylnicotinamidines, Suzuki coupling, antiproliferative, antibacterial, antioxidant

  2. Facile preparation and enhanced microwave absorption properties of flake carbonyl iron/Fe3O4 composite

    International Nuclear Information System (INIS)

    Min, Dandan; Zhou, Wancheng; Luo, Fa; Zhu, Dongmei

    2017-01-01

    Highlights: • Flake carbonyl iron/Fe 3 O 4 composites were prepared by surface oxidation technique. • Lower permittivity and modest permeability was obtained by the FCI/Fe 3 O 4 composites. • Enhanced absorption efficiency and broader absorption band were obtained. - Abstract: Flake carbonyl iron/Fe 3 O 4 (FCI/Fe 3 O 4 ) composites with enhanced microwave absorption properties were prepared by a direct and flexible surface oxidation technique. The phase structures, morphology, magnetic properties, frequency-dependent electromagnetic and microwave absorption properties of the composites were investigated. The measurement results showed that lower permittivity as well as modest permeability was obtained by the FCI/Fe 3 O 4 composites. The calculated microwave absorption properties indicated that enhanced absorption efficiency and broader absorption band were obtained by the FCI/Fe 3 O 4 composite comparing with the FCI composite. The absorption frequency range with reflection loss (RL) below −5 dB of FCI/Fe 3 O 4 composites at reaction time of 90 min at thickness of 1.5 mm is 13.3 GHz from 4.7 to 18 GHz, while the bandwidth of the FCI composite is only 5.9 GHz from 2.6 to 8.5 GHz at the same thickness. Thus, such absorbers could act as effective and wide broadband microwave absorbers in the GHz range.

  3. Enhanced photocatalytic properties of ZnO/reduced graphene oxide sheets (rGO) composites with controllable morphology and composition

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yanting, E-mail: 928221565@qq.com; Liu, Lin, E-mail: llspzjnu@163.com; Cui, Tingting, E-mail: wuleiwangyou@163.com; Tong, Guoxiu, E-mail: tonggx@zjnu.cn; Wu, Wenhua, E-mail: tongwu@zjnu.cn

    2017-08-01

    Highlights: • An easy one-step low-temperature chemical etching route for ZnO NR/rGO composites. • Modulation over the ZnO morphology and content in ZnO NR/rGO composites. • Investigating shape and content-dependent optical and photocatalytic properties. • Revealing the enhancement mechanism of optical and photocatalytic properties. - Abstract: ZnO with various morphologies and contents was used to decorate reduced graphene oxide (rGO) sheets via an easy one-step low-temperature chemical etching route to improve photocatalytic properties. The ZnO shape and content in ZnO/rGO composites were adjusted by changing aging time, heating mode, and rGO mass added. Shape and content-dependent optical and photocatalytic properties are observed in ZnO/rGO composites. A moderate amount of ZnO nanorings (NRs) decorated with rGO can significantly improve the light absorption and photo-luminescence emission because of plasmonic resonant absorption and plasmonic nanoantenna radiation, respectively. ZnO NR/rGO composites with a moderate ZnO content of 29.54 wt.% exhibit the optimum photocatalytic activity with a 0.025 min{sup −1} apparent rate constant, which is significantly higher than those of pure rGO (0.0085 min{sup −1}) and ZnO NRs (0.018 min{sup −1}). The improved performance is ascribed to the synergistic effect of enhanced adsorption capacity, plasmonic light absorption, plasmonic nanoantenna radiation, and the prolonged lifetime of photogenerated electron-hole pairs. Our findings not only offer insights into the plasmon enhanced optical and photocatalytic properties of ZnO NR/rGO composites but also suggest the possibility of fabricating ZnO NR/rGO photocatalyst with enhanced performance.

  4. Enhanced

    Directory of Open Access Journals (Sweden)

    Martin I. Bayala

    2014-06-01

    Full Text Available Land Surface Temperature (LST is a key parameter in the energy balance model. However, the spatial resolution of the retrieved LST from sensors with high temporal resolution is not accurate enough to be used in local-scale studies. To explore the LST–Normalised Difference Vegetation Index relationship potential and obtain thermal images with high spatial resolution, six enhanced image sharpening techniques were assessed: the disaggregation procedure for radiometric surface temperatures (TsHARP, the Dry Edge Quadratic Function, the Difference of Edges (Ts∗DL and three models supported by the relationship of surface temperature and water stress of vegetation (Normalised Difference Water Index, Normalised Difference Infrared Index and Soil wetness index. Energy Balance Station data and in situ measurements were used to validate the enhanced LST images over a mixed agricultural landscape in the sub-humid Pampean Region of Argentina (PRA, during 2006–2010. Landsat Thematic Mapper (TM and Moderate Resolution Imaging Spectroradiometer (EOS-MODIS thermal datasets were assessed for different spatial resolutions (e.g., 960, 720 and 240 m and the performances were compared with global and local TsHARP procedures. Results suggest that the Ts∗DL technique is the most adequate for simulating LST to high spatial resolution over the heterogeneous landscape of a sub-humid region, showing an average root mean square error of less than 1 K.

  5. Proapoptotic and Antiproliferative Effects of Thymus caramanicus on Human Breast Cancer Cell Line (MCF-7 and Its Interaction with Anticancer Drug Vincristine

    Directory of Open Access Journals (Sweden)

    Saeed Esmaeili-Mahani

    2014-01-01

    Full Text Available Thymus caramanicus Jalas is one of the species of thymus that grows in the wild in different regions of Iran. Traditionally, leaves of this plant are used in the treatment of diabetes, arthritis, and cancerous situation. Therefore, the present study was designed to investigate the selective cytotoxic and antiproliferative properties of Thymus caramanicus extract (TCE. MCF-7 human breast cancer cells were used in this study. Cytotoxicity of the extract was determined using MTT and neutral red assays. Biochemical markers of apoptosis (caspase 3, Bax, and Bcl-2 and cell proliferation (cyclin D1 were evaluated by immunoblotting. Vincristine was used as anticancer control drug in extract combination therapy. The data showed that incubation of cells with TCE (200 and 250 μg/mL significantly increased cell damage, activated caspase 3 and Bax/Bcl2 ratio. In addition, cyclin D1 was significantly decreased in TCE-treated cells. Furthermore, concomitant treatment of cells with extract and anticancer drug produced a significant cytotoxic effect as compared to extract or drugs alone. In conclusion, thymus extract has a potential proapoptotic/antiproliferative property against human breast cancer cells and its combination with chemotherapeutic agent vincristine may induce cell death effectively and be a potent modality to treat this type of cancer.

  6. Lactobacillus casei Exerts Anti-Proliferative Effects Accompanied by Apoptotic Cell Death and Up-Regulation of TRAIL in Colon Carcinoma Cells

    Science.gov (United States)

    Santarmaki, Valentina; Aindelis, Georgios; Tompoulidou, Evgenia; Lamprianidou, Eleftheria E.; Saxami, Georgia; Ypsilantis, Petros; Lampri, Evangeli S.; Simopoulos, Constantinos; Kotsianidis, Ioannis; Galanis, Alex; Kourkoutas, Yiannis; Dimitrellou, Dimitra; Chlichlia, Katerina

    2016-01-01

    Probiotic microorganisms such as lactic acid bacteria (LAB) exert a number of strain-specific health-promoting activities attributed to their immunomodulatory, anti-inflammatory and anti-carcinogenic properties. Despite recent attention, our understanding of the biological processes involved in the beneficial effects of LAB strains is still limited. To this end, the present study investigated the growth-inhibitory effects of Lactobacillus casei ATCC 393 against experimental colon cancer. Administration of live Lactobacillus casei (as well as bacterial components thereof) on murine (CT26) and human (HT29) colon carcinoma cell lines raised a significant concentration- and time-dependent anti-proliferative effect, determined by cell viability assays. Specifically, a dramatic decrease in viability of colon cancer cells co-incubated with 109 CFU/mL L. casei for 24 hours was detected (78% for HT29 and 52% for CT26 cells). In addition, live L. casei induced apoptotic cell death in both cell lines as revealed by annexin V and propidium iodide staining. The significance of the in vitro anti-proliferative effects was further confirmed in an experimental tumor model. Oral daily administration of 109 CFU live L. casei for 13 days significantly inhibited in vivo growth of colon carcinoma cells, resulting in approximately 80% reduction in tumor volume of treated mice. Tumor growth inhibition was accompanied by L. casei-driven up-regulation of the TNF-related apoptosis-inducing ligand TRAIL and down-regulation of Survivin. Taken together, these findings provide evidence for beneficial tumor-inhibitory, anti-proliferative and pro-apoptotic effects driven by this probiotic LAB strain. PMID:26849051

  7. Lactobacillus casei Exerts Anti-Proliferative Effects Accompanied by Apoptotic Cell Death and Up-Regulation of TRAIL in Colon Carcinoma Cells.

    Directory of Open Access Journals (Sweden)

    Angeliki Tiptiri-Kourpeti

    Full Text Available Probiotic microorganisms such as lactic acid bacteria (LAB exert a number of strain-specific health-promoting activities attributed to their immunomodulatory, anti-inflammatory and anti-carcinogenic properties. Despite recent attention, our understanding of the biological processes involved in the beneficial effects of LAB strains is still limited. To this end, the present study investigated the growth-inhibitory effects of Lactobacillus casei ATCC 393 against experimental colon cancer. Administration of live Lactobacillus casei (as well as bacterial components thereof on murine (CT26 and human (HT29 colon carcinoma cell lines raised a significant concentration- and time-dependent anti-proliferative effect, determined by cell viability assays. Specifically, a dramatic decrease in viability of colon cancer cells co-incubated with 10(9 CFU/mL L. casei for 24 hours was detected (78% for HT29 and 52% for CT26 cells. In addition, live L. casei induced apoptotic cell death in both cell lines as revealed by annexin V and propidium iodide staining. The significance of the in vitro anti-proliferative effects was further confirmed in an experimental tumor model. Oral daily administration of 10(9 CFU live L. casei for 13 days significantly inhibited in vivo growth of colon carcinoma cells, resulting in approximately 80% reduction in tumor volume of treated mice. Tumor growth inhibition was accompanied by L. casei-driven up-regulation of the TNF-related apoptosis-inducing ligand TRAIL and down-regulation of Survivin. Taken together, these findings provide evidence for beneficial tumor-inhibitory, anti-proliferative and pro-apoptotic effects driven by this probiotic LAB strain.

  8. Lactobacillus casei Exerts Anti-Proliferative Effects Accompanied by Apoptotic Cell Death and Up-Regulation of TRAIL in Colon Carcinoma Cells.

    Science.gov (United States)

    Tiptiri-Kourpeti, Angeliki; Spyridopoulou, Katerina; Santarmaki, Valentina; Aindelis, Georgios; Tompoulidou, Evgenia; Lamprianidou, Eleftheria E; Saxami, Georgia; Ypsilantis, Petros; Lampri, Evangeli S; Simopoulos, Constantinos; Kotsianidis, Ioannis; Galanis, Alex; Kourkoutas, Yiannis; Dimitrellou, Dimitra; Chlichlia, Katerina

    2016-01-01

    Probiotic microorganisms such as lactic acid bacteria (LAB) exert a number of strain-specific health-promoting activities attributed to their immunomodulatory, anti-inflammatory and anti-carcinogenic properties. Despite recent attention, our understanding of the biological processes involved in the beneficial effects of LAB strains is still limited. To this end, the present study investigated the growth-inhibitory effects of Lactobacillus casei ATCC 393 against experimental colon cancer. Administration of live Lactobacillus casei (as well as bacterial components thereof) on murine (CT26) and human (HT29) colon carcinoma cell lines raised a significant concentration- and time-dependent anti-proliferative effect, determined by cell viability assays. Specifically, a dramatic decrease in viability of colon cancer cells co-incubated with 10(9) CFU/mL L. casei for 24 hours was detected (78% for HT29 and 52% for CT26 cells). In addition, live L. casei induced apoptotic cell death in both cell lines as revealed by annexin V and propidium iodide staining. The significance of the in vitro anti-proliferative effects was further confirmed in an experimental tumor model. Oral daily administration of 10(9) CFU live L. casei for 13 days significantly inhibited in vivo growth of colon carcinoma cells, resulting in approximately 80% reduction in tumor volume of treated mice. Tumor growth inhibition was accompanied by L. casei-driven up-regulation of the TNF-related apoptosis-inducing ligand TRAIL and down-regulation of Survivin. Taken together, these findings provide evidence for beneficial tumor-inhibitory, anti-proliferative and pro-apoptotic effects driven by this probiotic LAB strain.

  9. Parallel Solid-Phase Synthesis Using a New Diethylsilylacetylenic Linker and Leading to Mestranol Derivatives with Potent Antiproliferative Activities on Multiple Cancer Cell Lines.

    Science.gov (United States)

    Dutour, Raphael; Maltais, Rene; Perreault, Martin; Roy, Jenny; Poirier, Donald

    2018-03-07

    RM-133 belongs to a new family of aminosteroid derivatives demonstrating interesting anticancer properties, as confirmed in vivo in four mouse cancer xenograft models. However, the metabolic stability of RM-133 needs to be improved. After investigation, the replacement of its androstane scaffold by a more stable estrane scaffold led to the development of the mestranol derivative RM-581. Using solid-phase strategy involving five steps, we quickly synthesized a series of RM-581 analogs using the recently-developed diethylsilyl acetylenic linker. To establish structure-activity relationships, we then investigated their antiproliferative potency on a panel of cancer cell lines from various cancers (breast, prostate, ovarian and pancreatic). Some of the mestranol derivatives have shown in vitro anticancer activities that are close to, or better than those observed for RM-581. Compound 23, a mestranol derivative having a ((3,5-dimethylbenzoyl)-L-prolyl)piperazine side chain at position C2, was found to be active as an antiproliferative agent (IC50 = 0.38 ± 0.34 to 3.17 ± 0.10 µM) and to be twice as active as RM-581 on LNCaP, PC-3, MCF-7, PANC-1 and OVCAR-3 cancer cells (IC50 = 0.56 ± 0.30, 0.89 ± 0.63, 1.36 ± 0.31, 2.47 ± 0.91 and 3.17 ± 0.10 µM, respectively). Easily synthesized in good yields by both solid-phase organic synthesis and classic solution-phase chemistry, this promising candidate could be used as an antiproliferative agent on a variety of cancers, notably pancreatic and ovarian cancers, both having very bad prognoses. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  10. Amorphous and crystalline TiO2 nanotube arrays for enhanced Li-ion intercalation properties.

    Science.gov (United States)

    Guan, Dongsheng; Cai, Chuan; Wang, Ying

    2011-04-01

    We have employed a simple process of anodizing Ti foils to prepare TiO2 nanotube arrays which show enhanced electrochemical properties for applications as Li-ion battery electrode materials. The lengths and pore diameters of TiO2 nanotubes can be finely tuned by varying voltage, electrolyte composition, or anodization time. The as-prepared nanotubes are amorphous and can be converted into anatase nanotubes with heat treatment at 480 degrees C. Rutile crystallites emerge in the anatase nanotube when the annealing temperature is increased to 580 degrees C, resulting in TiO2 nanotubes of mixed phases. The morphological features of nanotubes remain unchanged after annealing. Li-ion insertion performance has been studied for amorphous and crystalline TiO2 nanotube arrays. Amorphous nanotubes with a length of 3.0 microm and an outer diameter of 125 nm deliver a capacity of 91.2 microA h cm(-2) at a current density of 400 microA cm(-2), while those with a length of 25 microm and an outer diameter of 158 nm display a capacity of 533 microA h cm-2. When the 3-microm long nanotubes become crystalline, they deliver lower capacities: the anatase nanotubes and nanotubes of mixed phases show capacities of 53.8 microA h cm-2 and 63.1 microA h cm(-2), respectively at the same current density. The amorphous nanotubes show excellent capacity retention ability over 50 cycles. The cycled nanotubes show little change in morphology compared to the nanotubes before electrochemical cycling. All the TiO2 nanotubes demonstrate higher capacities than amorphous TiO2 compact layer reported in literature. The amorphous TiO2 nanotubes with a length of 1.9 microm exhibit a capacity five times higher than that of TiO2 compact layer even when the nanotube array is cycled at a current density 80 times higher than that for the compact layer. These results suggest that anodic TiO2 nanotube arrays are promising electrode materials for rechargeable Li-ion batteries.

  11. Enhancing Electrophoretic Display Lifetime: Thiol-Polybutadiene Evaporation Barrier Property Response to Network Microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Cook, Caitlyn Christian [California State Polytechnic State Univ., San Luis Obispo, CA (United States)

    2017-02-27

    An evaporation barrier is required to enhance the lifetime of electrophoretic deposition (EPD) displays. As EPD functions on the basis of reversible deposition and resuspension of colloids suspended in a solvent, evaporation of the solvent ultimately leads to device failure. Incorporation of a thiol-polybutadiene elastomer into EPD displays enabled display lifetime surpassing six months in counting and catalyzed rigid display transition into a flexible package. Final flexible display transition to mass production compels an electronic-ink approach to encapsulate display suspension within an elastomer shell. Final thiol-polybutadiene photosensitive resin network microstructure was idealized to be dense, homogeneous, and expose an elastic response to deformation. Research at hand details an approach to understanding microstructural change within display elastomers. Polybutadiene-based resin properties are modified via polymer chain structure, with and without added aromatic urethane methacrylate difunctionality, and in measuring network response to variation in thiol and initiator concentration. Dynamic mechanical analysis results signify that cross-linked segments within a difunctionalized polybutadiene network were on average eight times more elastically active than that of linked segments within a non-functionalized polybutadiene network. Difunctionalized polybutadiene samples also showed a 2.5 times greater maximum elastic modulus than non-functionalized samples. Hybrid polymer composed of both polybutadiene chains encompassed TE-2000 stiffness and B-1000 elasticity for use in encapsulating display suspension. Later experiments measured kinetic and rheological response due to alteration in dithiol cross-linker chain length via real time Fourier transform infrared spectroscopy and real-time dynamic rheology. Distinct differences were discovered between dithiol resin systems, as maximum thiol conversion achieved in short and long chain length dithiols was 86% and

  12. Antioxidative and in vitro antiproliferative activity of Arctium lappa root extracts

    Science.gov (United States)

    2011-01-01

    Background Arctium lappa, known as burdock, is widely used in popular medicine for hypertension, gout, hepatitis and other inflammatory disorders. Pharmacological studies indicated that burdock roots have hepatoprotective, anti-inflammatory, free radical scavenging and antiproliferative activities. The aim of this study was to evaluate total phenolic content, radical scavenging activity by DPPH and in vitro antiproliferative activity of different A. lappa root extracts. Methods Hot and room temperature dichloromethanic, ethanolic and aqueous extracts; hydroethanolic and total aqueous extract of A. lappa roots were investigated regarding radical scavenging activity by DPPH, total phenolic content by Folin-Ciocalteau method and antiproliferative in vitro activity was evaluated in human cancer cell lines. The hydroethanolic extract analyzed by high-resolution electrospray ionization mass spectroscopy. Results Higher radical scavenging activity was found for the hydroethanolic extract. The higher phenolic contents were found for the dichloromethane, obtained both by Soxhlet and maceration extraction and hydroethanolic extracts. The HRESI-MS demonstrated the presence of arctigenin, quercetin, chlorogenic acid and caffeic acid compounds, which were identified by comparison with previous data. The dichloromethane extracts were the only extracts that exhibited activity against cancer cell lines, especially for K562, MCF-7 and 786-0 cell lines. Conclusions The hydroethanolic extracts exhibited the strongest free radical scavenging activity, while the highest phenolic content was observed in Soxhlet extraction. Moreover, the dichloromethanic extracts showed selective antiproliferative activity against K562, MCF-7 and 786-0 human cancer cell lines. PMID:21429215

  13. Antioxidative and in vitro antiproliferative activity of Arctium lappa root extracts.

    Science.gov (United States)

    Predes, Fabricia S; Ruiz, Ana L T G; Carvalho, João E; Foglio, Mary A; Dolder, Heidi

    2011-03-23

    Arctium lappa, known as burdock, is widely used in popular medicine for hypertension, gout, hepatitis and other inflammatory disorders. Pharmacological studies indicated that burdock roots have hepatoprotective, anti-inflammatory, free radical scavenging and antiproliferative activities. The aim of this study was to evaluate total phenolic content, radical scavenging activity by DPPH and in vitro antiproliferative activity of different A. lappa root extracts. Hot and room temperature dichloromethanic, ethanolic and aqueous extracts; hydroethanolic and total aqueous extract of A. lappa roots were investigated regarding radical scavenging activity by DPPH, total phenolic content by Folin-Ciocalteau method and antiproliferative in vitro activity was evaluated in human cancer cell lines. The hydroethanolic extract analyzed by high-resolution electrospray ionization mass spectroscopy. Higher radical scavenging activity was found for the hydroethanolic extract. The higher phenolic contents were found for the dichloromethane, obtained both by Soxhlet and maceration extraction and hydroethanolic extracts. The HRESI-MS demonstrated the presence of arctigenin, quercetin, chlorogenic acid and caffeic acid compounds, which were identified by comparison with previous data. The dichloromethane extracts were the only extracts that exhibited activity against cancer cell lines, especially for K562, MCF-7 and 786-0 cell lines. The hydroethanolic extracts exhibited the strongest free radical scavenging activity, while the highest phenolic content was observed in Soxhlet extraction. Moreover, the dichloromethanic extracts showed selective antiproliferative activity against K562, MCF-7 and 786-0 human cancer cell lines. © 2011 Predes et al; licensee BioMed Central Ltd.

  14. Antiproliferative and Pro-apoptotic activities of the stem bark of ...

    African Journals Online (AJOL)

    Persea americana (Lauraceae) have been used in traditional medicine for a wide range of illness and some of these uses have been proven scientifically. The aim of this present study is to screen for the phytochemical content, determine the proximate parameter and determine the antiproliferative and apoptotic effects of ...

  15. A Simple and Sensitive High-Content Assay for the Characterization of Antiproliferative Therapeutic Antibodies.

    Science.gov (United States)

    Stengl, Andreas; Hörl, David; Leonhardt, Heinrich; Helma, Jonas

    2017-03-01

    Monoclonal antibodies (mAbs) have become a central class of therapeutic agents in particular as antiproliferative compounds. Their often complex modes of action require sensitive assays during early, functional characterization. Current cell-based proliferation assays often detect metabolites that are indicative of metabolic activity but do not directly account for cell proliferation. Measuring DNA replication by incorporation of base analogues such as 5-bromo-2'-deoxyuridine (BrdU) fills this analytical gap but was previously restricted to bulk effect characterization in enzyme-linked immunosorbent assay formats. Here, we describe a cell-based assay format for the characterization of antiproliferative mAbs regarding potency and mode of action in a single experiment. The assay makes use of single cell-based high-content-analysis (HCA) for the reliable quantification of replicating cells and DNA content via 5-ethynyl-2'-deoxyuridine (EdU) and 4',6-diamidino-2-phenylindole (DAPI), respectively, as sensitive measures of antiproliferative mAb activity. We used trastuzumab, an antiproliferative therapeutic antibody interfering with HER2 cell surface receptor-mediated growth signal transduction, and HER2-overexpressing cell lines BT474 and SKBR3 to demonstrate up to 10-fold signal-to-background (S/B) ratios for treated versus untreated cells and a shift in cell cycle profiles indicating antibody-induced cell cycle arrest. The assay is simple, cost-effective, and sensitive, providing a cell-based format for preclinical characterization of therapeutic mAbs.

  16. Antioxidative and in vitro antiproliferative activity of Arctium lappa root extracts

    Directory of Open Access Journals (Sweden)

    Carvalho João E

    2011-03-01

    Full Text Available Abstract Background Arctium lappa, known as burdock, is widely used in popular medicine for hypertension, gout, hepatitis and other inflammatory disorders. Pharmacological studies indicated that burdock roots have hepatoprotective, anti-inflammatory, free radical scavenging and antiproliferative activities. The aim of this study was to evaluate total phenolic content, radical scavenging activity by DPPH and in vitro antiproliferative activity of different A. lappa root extracts. Methods Hot and room temperature dichloromethanic, ethanolic and aqueous extracts; hydroethanolic and total aqueous extract of A. lappa roots were investigated regarding radical scavenging activity by DPPH, total phenolic content by Folin-Ciocalteau method and antiproliferative in vitro activity was evaluated in human cancer cell lines. The hydroethanolic extract analyzed by high-resolution electrospray ionization mass spectroscopy. Results Higher radical scavenging activity was found for the hydroethanolic extract. The higher phenolic contents were found for the dichloromethane, obtained both by Soxhlet and maceration extraction and hydroethanolic extracts. The HRESI-MS demonstrated the presence of arctigenin, quercetin, chlorogenic acid and caffeic acid compounds, which were identified by comparison with previous data. The dichloromethane extracts were the only extracts that exhibited activity against cancer cell lines, especially for K562, MCF-7 and 786-0 cell lines. Conclusions The hydroethanolic extracts exhibited the strongest free radical scavenging activity, while the highest phenolic content was observed in Soxhlet extraction. Moreover, the dichloromethanic extracts showed selective antiproliferative activity against K562, MCF-7 and 786-0 human cancer cell lines.

  17. [Variability of the sensitivity of human lymphocytes to the antiproliferative action of alkylating agents].

    Science.gov (United States)

    Veremko, L N; Telegin, L Iu; Pevnitskii, L A

    1983-05-01

    A study was made of variability of the sensitivity of peripheral blood lymphocytes from different donors to an antiproliferative action of cyclophosphamide and thiophosphamide. A similar degree of the sensitivity was revealed to alkylating agents differing in the action mode, with this degree being independent of the "stimulation index" magnitude.

  18. Antioxidant, anti-inflammatory and antiproliferative activities of Kalanchoe gracilis (L.) DC stem.

    Science.gov (United States)

    Lai, Zhen-Rung; Ho, Yu-Ling; Huang, Shun-Chieh; Huang, Tai-Hung; Lai, Shang-Chih; Tsai, Jen-Chieh; Wang, Ching-Ying; Huang, Guan-Jhong; Chang, Yuan-Shiun

    2011-01-01

    Oxidative stress and inflammation are related to several chronic diseases including cancer and atherosclerosis. Kalanchoe gracilis (L.) DC is a special folk medicinal plant in Taiwan. The aim of this study was to evaluate the antioxidant, anti-inflammatory and antiproliferative activities of the methanolic extract and fractions of the stem of K. gracilis. TEAC, total phenolic compound content, total flavonoid content, DPPH radical scavenging activity, reducing power, inhibition of NO production in LPS-induced RAW264.7 cells, and inhibition of cancer cell proliferation were analyzed. Among all fractions, the chloroform fraction showed the highest TEAC and DPPH radical scavenging activities. The chloroform fraction also had the highest content of polyphenols and flavonoids. Chloroform fractions also decreased LPS-induced NO production and expressions of iNOS and COX-2 in RAW264.7 cells. The antiproliferative activities of the methanolic extract and fractions were studied in vitro using HepG2 cells, and the results were consistent with their antioxidant capacities. Chloroform fractions had the highest antiproliferative activity with an IC(50) of 136.85 ± 2.32 μg/ml. Eupafolin also had good pharmacological activity in the antioxidant, anti-inflammation and antiproliferative. Eupafolin might be an important bioactive compound in the stem of K. gracilis. The above experimental data indicated that the stem of K. gracilis is a potent antioxidant medicinal plant, and such efficacy may be mainly attributed to its polyphenolic compounds.

  19. Biochemical characterization and antioxidant and antiproliferative activities of different Ganoderma collections.

    Science.gov (United States)

    Saltarelli, Roberta; Ceccaroli, Paola; Buffalini, Michele; Vallorani, Luciana; Casadei, Lucia; Zambonelli, Alessandra; Iotti, Mirco; Badalyan, Susanna; Stocchi, Vilberto

    2015-01-01

    The aim of this study was to conduct a molecular and biochemical characterization and to compare the antioxidant and antiproliferative activities of four Ganoderma isolates belonging to Ganoderma lucidum (Gl-4, Gl-5) and Ganoderma resinaceum (F-1, F-2) species. The molecular identification was performed by ITS and IGS sequence analyses and the biochemical characterization by enzymatic and proteomic approaches. The antioxidant activity of the ethanolic extracts was compared by three different methods and their flavonoid contents were also analyzed by high-performance liquid chromatography. The antiproliferative effect on U937 cells was determined by MTT assay. The studied mycelia differ both in the enzymatic activities and protein content. The highest content in total phenol and the highest antioxidant activity for DPPH free radical scavenging and chelating activity on Fe(2+) were observed with the Gl-4 isolate of G. lucidum. The presence of quercetin, rutin, myricetin, and morin as major flavonoids with effective antioxidant activity was detected. The ethanolic extracts from mycelia of G. lucidum isolates possess a substantial antiproliferative activity against U937 cells in contrast to G. resinaceum in which the antiproliferative effects were insignificant. This study provides a comparison between G. lucidum and G. resinaceum mycelial strains, and shows that G. resinaceum could be utilized to obtain several bioactive compounds. © 2015 S. Karger AG, Basel.

  20. Synthesis and Antiproliferative Activity of Minor Hops Prenylflavonoids and New Insights on Prenyl Group Cyclization

    Directory of Open Access Journals (Sweden)

    Jarosław Popłoński

    2018-03-01

    Full Text Available Synthesis of minor prenylflavonoids found in hops and their non-natural derivatives were performed. The antiproliferative activity of the obtained compounds against some human cancer cell lines was investigated. Using xanthohumol isolated from spent hops as a lead compound, a series of minor hop prenylflavonoids and synthetic derivatives were obtained by isomerization, cyclisation, oxidative-cyclisation, oxidation, reduction and demethylation reactions. Three human cancer cell lines—breast (MCF-7, prostate (PC-3 and colon (HT-29—were used in antiproliferative assays, with cisplatin as a control compound. Five minor hop prenyl flavonoids and nine non-natural derivatives of xanthohumol have been synthetized. Syntheses of xanthohumol K, its dihydro- and tetrahydro-derivatives and 1″,2″,α,β-tetrahydroxanthohumol C were described for the first time. All of the minor hops prenyl flavonoids exhibited strong to moderate antiproliferative activity in vitro. The minor hops flavonoids xanthohumol C and 1″,2″-dihydroxanthohumol K and non-natural 2,3-dehydroisoxanthohumol exhibited the activity comparable to cisplatin. Results described in the article suggest that flavonoids containing chromane- and chromene-like moieties, especially chalcones, are potent antiproliferative agents. The developed new efficient, regioselective cyclisation reaction of the xanthohumol prenyl group to 1″,2″-dihydroxantohumol K may be used in the synthesis of other compounds with the chromane moiety.

  1. Polymers for enhanced oil recovery : A paradigm for structure-property relationship in aqueous solution

    NARCIS (Netherlands)

    Wever, D. A. Z.; Picchioni, F.; Broekhuis, A. A.

    Recent developments in the field of water-soluble polymers aimed at enhancing the aqueous solution viscosity are reviewed. Classic and novel associating water-soluble polymers for enhanced oil recovery (EOR) applications are discussed along with their limitations. Particular emphasis is placed on

  2. A Nanotube Surface Reinforced Graphite Fiber Exhibiting Significantly Enhanced Properties, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Nanotechnology which includes carbon nanotubes has the potential to produce materials that exhibit properties beyond those expected from conventional materials which...

  3. Astemizole synergizes calcitriol antiproliferative activity by inhibiting CYP24A1 and upregulating VDR: a novel approach for breast cancer therapy.

    Directory of Open Access Journals (Sweden)

    Janice García-Quiroz

    Full Text Available Calcitriol antiproliferative effects include inhibition of the oncogenic ether-à-go-go-1 potassium channel (Eag1 expression, which is necessary for cell cycle progression and tumorigenesis. Astemizole, a new promising antineoplastic drug, targets Eag1 by blocking ion currents. Herein, we characterized the interaction between calcitriol and astemizole as well as their conjoint antiproliferative action in SUM-229PE, T-47D and primary tumor-derived breast cancer cells.Molecular markers were studied by immunocytochemistry, Western blot and real time PCR. Inhibitory concentrations were determined by dose-response curves and metabolic activity assays. At clinically achievable drug concentrations, synergistic antiproliferative interaction was observed between calcitriol and astemizole, as calculated by combination index analysis (CI <1. Astemizole significantly enhanced calcitriol's growth-inhibitory effects (3-11 folds, P<0.01. Mean IC(20 values were 1.82 ± 2.41 nM and 1.62 ± 0.75 µM; for calcitriol (in estrogen receptor negative cells and astemizole, respectively. Real time PCR showed that both drugs alone downregulated, while simultaneous treatment further reduced Ki-67 and Eag1 gene expression (P<0.05. Astemizole inhibited basal and calcitriol-induced CYP24A1 and CYP3A4 mRNA expression (cytochromes involved in calcitriol and astemizole degradation in breast and hepatoma cancer cells, respectively, while upregulated vitamin D receptor (VDR expression.Astemizole synergized calcitriol antiproliferative effects by downregulating CYP24A1, upregulating VDR and targeting Eag1. This study provides insight into the molecular mechanisms involved in astemizole-calcitriol combined antineoplastic effect, offering scientific support to test both compounds in combination in further preclinical and clinical studies of neoplasms expressing VDR and Eag1. VDR-negative tumors might also be sensitized to calcitriol antineoplastic effects by the use of astemizole

  4. Enhanced mechanical properties of linear segmented shape memory poly(urethane-urea) by incorporating flexible PEG400 and rigid piperazine

    Science.gov (United States)

    Zhang, Xiao-Yan; Ma, Yu-Fei; Li, Yong-Gang; Wang, Pin-Pin; Wang, Yuan-Liang; Luo, Yan-Feng

    2012-12-01

    The goal of this study is to design and synthesize a linear segmented shape memory poly(urethane-urea) (SMPUU) that possesses near-body-temperature shape memory temperature ( T tran) and enhanced mechanical properties by incorporating flexible poly(ethylene glycol) 400 (PEG400) to form poly(D,L-lactic acid)-based macrodiols (PDLLA-PEG400-PDLLA) and then rigid piperazine (PPZ) as a chain extender to form the desired SMPUUs (PEG400-PUU-PPZ). PEG400 increased M n while maintaining a lower T g of PDLLA-PEG400-PDLLA, which together with PPZ improved the mechanical properties of PEG400-PUU-PPZ. The obtained optimum SMPUU with enhanced mechanical properties ( σ y = 24.28 MPa; ɛ f = 698%; U f = 181.5 MJ/m3) and a T g of 40.62°C exhibited sound shape memory properties as well, suggesting a promising SMPUU for in vivo biomedical applications.

  5. Enhanced mechanical properties and increased corrosion resistance of a biodegradable magnesium alloy by plasma electrolytic oxidation (PEO)

    Energy Technology Data Exchange (ETDEWEB)

    White, Leon; Koo, Youngmi [FIT BEST Laboratory, Engineering Research Center, Department of Chemical, Biological, and Bio Engineering, North Carolina A& T State University, Greensboro, NC 27411 (United States); Neralla, Sudheer [Jet-Hot LLC, Burlington, NC 27215 (United States); Sankar, Jagannathan [FIT BEST Laboratory, Engineering Research Center, Department of Chemical, Biological, and Bio Engineering, North Carolina A& T State University, Greensboro, NC 27411 (United States); Yun, Yeoheung, E-mail: yyun@ncat.edu [FIT BEST Laboratory, Engineering Research Center, Department of Chemical, Biological, and Bio Engineering, North Carolina A& T State University, Greensboro, NC 27411 (United States)

    2016-06-15

    Highlights: • Plasma electrolytic oxidation (PEO) method was developed to control corrosion, porosity, and mechanical property. • Mechanical properties of PEO-coated AZ31 alloys were affected by the different electrolyte. • Mechanical properties and corrosion resistance of PEO-coated AZ31 alloys were compared with uncoated one. - Abstract: We report the enhanced mechanical properties of AZ31 magnesium alloys by plasma electrolytic oxidation (PEO) coating in NaOH, Na{sub 2}SiO{sub 3}, KF and NaH{sub 2}PO{sub 4}·2H{sub 2}O containing electrolytes. Mechanical properties including wear resistance, surface hardness and elastic modulus were increased for PEO-coated AZ31 Mg alloys (PEO-AZ31). DC polarization in Hank's solution indicating that the corrosion resistance significantly increased for PEO-coating in KF-contained electrolyte. Based on these results, the PEO coating method shows promising potential for use in biodegradable implant applications where tunable corrosion and mechanical properties are needed.

  6. Enhanced thermal and mechanical properties of epoxy composites by mixing thermotropic liquid crystalline epoxy grafted graphene oxide

    Directory of Open Access Journals (Sweden)

    B. Qi

    2014-07-01

    Full Text Available Graphene oxide (GO sheets were chemically grafted with thermotropic liquid crystalline epoxy (TLCP. Then we fabricated composites using TLCP-g-GO as reinforcing filler. The mechanical properties and thermal properties of composites were systematically investigated. It is found that the thermal and mechanical properties of the composites are enhanced effectively by the addition of fillers. For instance, the composites containing 1.0 wt% of TLCP-g-GO present impact strength of 51.43 kJ/m2, the tensile strength of composites increase from 55.43 to 80.85 MPa, the flexural modulus of the composites increase by more than 48%. Furthermore, the incorporation of fillers is effective to improve the glass transition temperature and thermal stability of the composites. Therefore, the presence of the TLCP-g-GO in the epoxy matrix could make epoxy not only stronger but also tougher.

  7. Enhanced ferroelectric photoelectrochemical properties of polycrystalline BiFeO{sub 3} film by decorating with Ag nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Qing; Shen, Mingrong; Fang, Liang, E-mail: lfang@suda.edu.cn [College of Physics, Optoelectronics and Energy and Jiangsu Key Laboratory of Thin Films, Soochow University, Suzhou 215006 (China); Zhou, Yang; You, Lu; Wang, Junling [School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore 639798 (Singapore)

    2016-01-11

    Polycrystalline BiFeO{sub 3} (BFO) films are fabricated on Pt/Ti/SiO{sub 2}/Si(100) substrate as photoelectrode using sol-gel method. The microstructure, optical, and photoelectrochemical (PEC) properties of the films are characterized and optimized by controlling the film thickness. Moreover, the PEC properties of the BFO films are dependent on ferroelectric polarization, which is mainly ascribed to the modulation of band structure at the BFO/electrolyte interface by the polarization. Further enhancement of PEC properties is obtained by decorating the samples with appropriate amounts of Ag nanoparticles, which is attributed to the reduced electron-hole recombination, and localized surface plasmon resonance effect of Ag nanoparticles.

  8. Enhancement of Moisture Protective Properties and Stability of Pectin through Formation of a Composite Film: Effects of Shellac and Plasticizer.

    Science.gov (United States)

    Luangtana-Anan, Manee; Soradech, Sitthiphong; Saengsod, Suthep; Nunthanid, Jurairat; Limmatvapirat, Sontaya

    2017-12-01

    The aim of this investigation was to develop the high moisture protective ability and stable pectin through the design of composite films based on varying shellac concentrations. A film casting method was applied to prepare a free film. The moisture protective properties and mechanical properties were investigated. The findings was the composite films exhibited the reductions in the hydrophilicity, water vapor permeability, and the moisture content compared with pectin films. The single and composite films were then study for their stability at 40 °C and 75% RH for 90 d. Among the concentrations of shellac, 50% (w/w) could improve stability in terms of moisture protection after 90 d of storage, whereas lower concentrations of shellac (10% to 40%) could not achieve this. However, the higher shellac content also contributed to weaker mechanical properties. The mechanical improvement and stability of composite films with the incorporation of plasticizers were further investigated. Polyethylene glycol 400 and diethyl phthalate at a concentration of 10% were used. The results indicated that both plasticizers could enhance the mechanical characteristics and had a slight effect on moisture protection. The stability of pectin in terms of moisture protective properties could, therefore, be modified through the fabrication of composite films with hydrophobic polymers, that is, shellac and the addition of proper plasticizers to enhance mechanical properties, which could offer wide applications for edible film in food, agro, and pharmaceutical industries. The composite film with 50% shellac could improve moisture protective properties of pectin film. Adding a plasticizer could build up the higher mechanical characteristics of composite film. Stability of pectin could be modified by fabrication of composite films with proper content of shellac and plasticizer. © 2017 Institute of Food Technologists®.

  9. On the enhancement of pervaporation properties of plasma-deposited hybrid silica membranes

    Energy Technology Data Exchange (ETDEWEB)

    Ngamou, P.H.T.; Creatore, M. [Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands); Overbeek, J.P.; Kreiter, R.; Van Veen, H.M.; Vente, J.F. [ECN, Energy research Centre of the Netherlands, Petten (Netherlands); Cuperus, P.F. [SolSep BV, Apeldoorn (Netherlands)

    2013-06-24

    The separation performance of a polymeric-supported hybrid silica membrane in the dehydration process of a butanol-water mixture at 95C has been enhanced by applying a bias to the substrate during the plasma deposition.

  10. Facile preparation and enhanced microwave absorption properties of flake carbonyl iron/Fe{sub 3}O{sub 4} composite

    Energy Technology Data Exchange (ETDEWEB)

    Min, Dandan, E-mail: mdd4776@126.com; Zhou, Wancheng; Luo, Fa; Zhu, Dongmei

    2017-08-01

    Highlights: • Flake carbonyl iron/Fe{sub 3}O{sub 4} composites were prepared by surface oxidation technique. • Lower permittivity and modest permeability was obtained by the FCI/Fe{sub 3}O{sub 4} composites. • Enhanced absorption efficiency and broader absorption band were obtained. - Abstract: Flake carbonyl iron/Fe{sub 3}O{sub 4} (FCI/Fe{sub 3}O{sub 4}) composites with enhanced microwave absorption properties were prepared by a direct and flexible surface oxidation technique. The phase structures, morphology, magnetic properties, frequency-dependent electromagnetic and microwave absorption properties of the composites were investigated. The measurement results showed that lower permittivity as well as modest permeability was obtained by the FCI/Fe{sub 3}O{sub 4} composites. The calculated microwave absorption properties indicated that enhanced absorption efficiency and broader absorption band were obtained by the FCI/Fe{sub 3}O{sub 4} composite comparing with the FCI composite. The absorption frequency range with reflection loss (RL) below −5 dB of FCI/Fe{sub 3}O{sub 4} composites at reaction time of 90 min at thickness of 1.5 mm is 13.3 GHz from 4.7 to 18 GHz, while the bandwidth of the FCI composite is only 5.9 GHz from 2.6 to 8.5 GHz at the same thickness. Thus, such absorbers could act as effective and wide broadband microwave absorbers in the GHz range.

  11. Enhanced mechanical properties and biocompatibility of novel hydroxyapatite/TOPAS hybrid composite for bone tissue engineering applications

    Energy Technology Data Exchange (ETDEWEB)

    Ain, Qurat Ul [Department of Materials Engineering, School of Chemical and Materials Engineering, National University of Sciences and Technology, H-12, Islamabad (Pakistan); Khan, Ahmad Nawaz, E-mail: ahmad.nawaz@scme.nust.edu.pk [Department of Materials Engineering, School of Chemical and Materials Engineering, National University of Sciences and Technology, H-12, Islamabad (Pakistan); Nabavinia, Mahboubeh [Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA (United States); Mujahid, Mohammad [Department of Materials Engineering, School of Chemical and Materials Engineering, National University of Sciences and Technology, H-12, Islamabad (Pakistan)

    2017-06-01

    The bioactivity and mechanical properties of hybrid composites of hydroxyapatite (HA) in cyclic olefinic copolymer (COC) also known commercially as TOPAS are investigated, first time, for regeneration and repair of the bone tissues. HA is synthesized to obtain the spherically shaped nanoparticles in the size range of 60 ± 20 nm. Various concentrations of HA ranging from 1 to 30 wt% are dispersed in TOPAS using sodium dodecyl sulfate (SDS) coupling agent for better dispersion and interaction of hydrophilic HA with hydrophobic TOPAS. Scanning electron microscope shows the uniform dispersion of HA ≤ 10 wt% in TOPAS and at higher concentrations > 10 wt%, agglomeration occurs in the hybrid composites. Tunable mechanical properties are achieved as the compressive modulus and strength are increased around 140% from 6.4 to 15.3 MPa and 185% from 0.26 to 0.74 MPa, respectively. Such increase in the mechanical properties of TOPAS is attributed to the anchoring of the polymer chains in the vicinity of HA nanoparticles owing to better dispersion and interfacial interactions. In comparison to neat TOPAS, hybrid composites of TOPAS/HA promoted the cell adhesion and proliferation significantly. The cell density and proliferation of TOPAS/HA hybrid composites is enhanced 9 and 3 folds, respectively, after 1 day culturing in preosteoblasts cells. Moreover, the morphology of cells changed from spherical to flattened spread morphology demonstrating clearly the migration of the cells for the formation of interconnected cellular network. Additionally, very few dead cells are found in hybrid composites showing their cytocompatibility. Overall, the hybrid composites of TOPAS/HA exhibited superior strength and stiffness along with enhanced cytocompatibility for bone tissue engineering applications. - Highlights: • TOPAS/HA hybrid composites exhibited enhanced mechanical properties owing to better dispersion and interaction of HA. • Without affecting the degradation rate, the

  12. Enhanced mechanical properties and biocompatibility of novel hydroxyapatite/TOPAS hybrid composite for bone tissue engineering applications

    International Nuclear Information System (INIS)

    Ain, Qurat Ul; Khan, Ahmad Nawaz; Nabavinia, Mahboubeh; Mujahid, Mohammad

    2017-01-01

    The bioactivity and mechanical properties of hybrid composites of hydroxyapatite (HA) in cyclic olefinic copolymer (COC) also known commercially as TOPAS are investigated, first time, for regeneration and repair of the bone tissues. HA is synthesized to obtain the spherically shaped nanoparticles in the size range of 60 ± 20 nm. Various concentrations of HA ranging from 1 to 30 wt% are dispersed in TOPAS using sodium dodecyl sulfate (SDS) coupling agent for better dispersion and interaction of hydrophilic HA with hydrophobic TOPAS. Scanning electron microscope shows the uniform dispersion of HA ≤ 10 wt% in TOPAS and at higher concentrations > 10 wt%, agglomeration occurs in the hybrid composites. Tunable mechanical properties are achieved as the compressive modulus and strength are increased around 140% from 6.4 to 15.3 MPa and 185% from 0.26 to 0.74 MPa, respectively. Such increase in the mechanical properties of TOPAS is attributed to the anchoring of the polymer chains in the vicinity of HA nanoparticles owing to better dispersion and interfacial interactions. In comparison to neat TOPAS, hybrid composites of TOPAS/HA promoted the cell adhesion and proliferation significantly. The cell density and proliferation of TOPAS/HA hybrid composites is enhanced 9 and 3 folds, respectively, after 1 day culturing in preosteoblasts cells. Moreover, the morphology of cells changed from spherical to flattened spread morphology demonstrating clearly the migration of the cells for the formation of interconnected cellular network. Additionally, very few dead cells are found in hybrid composites showing their cytocompatibility. Overall, the hybrid composites of TOPAS/HA exhibited superior strength and stiffness along with enhanced cytocompatibility for bone tissue engineering applications. - Highlights: • TOPAS/HA hybrid composites exhibited enhanced mechanical properties owing to better dispersion and interaction of HA. • Without affecting the degradation rate, the

  13. Enhanced field emission properties of tilted graphene nanoribbons on aggregated TiO{sub 2} nanotube arrays

    Energy Technology Data Exchange (ETDEWEB)

    Hung, Shang-Chao, E-mail: schung99@gmail.com [Department of Information Technology & Communication, Shih Chien University Kaohsiung Campus, Neimen, Kaohsiung 845, Taiwan (China); Chen, Yu-Jyun [Graduate Institute of Electro-Optical Engineering & Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China)

    2016-07-15

    Highlights: • Graphene nanoribbons (GNBs) slanted on aggregate TiO{sub 2} nanotube (A-TNTs) as field-emitters. • Turn-on electric field and field enhancement factor β are dependent on the substrate morphology. • Various quantities of GNRs are deposited on top of A-TNTs (GNRs/A-TNTs) with different morphologies. • With an increase of GNBs compositions, the specimens' turn-on electric field is reduced to 2.8 V/μm. • The field enhancement factor increased rapidly to about 1964 with the addition of GNRs. - Abstract: Graphene nanoribbons (GNRs) slanted on aggregate TiO{sub 2} nanotube arrays (A-TNTs) with various compositions as field-emitters are reported. The morphology, crystalline structure, and composition of the as-obtained specimens were characterized by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and Raman spectrometry. The dependence of the turn-on electric field and the field enhancement factor β on substrate morphology was studied. An increase of GNRs reduces the specimens’ turn-on electric field to 2.8 V/μm and the field enhancement factor increased rapidly to about 1964 with the addition of GNRs. Results show a strong dependence of the field emission on GNR composition aligned with the gradient on the top of the A-TNT substrate. Enhanced FE properties of the modified TNTs can be mainly attributed to their improved electrical properties and rougher surface morphology.

  14. Going greener: Synthesis of fully biobased unsaturated polyesters for styrene crosslinked resins with enhanced thermomechanical properties

    Directory of Open Access Journals (Sweden)

    C. S. M. F. Costa

    2017-11-01

    Full Text Available The main goal of this work was the development of fully biobased unsaturated polyesters (UPs that upon crosslinking with unsaturated monomers (UM could lead to greener unsaturated polyester resins (UPRs with similar thermomechanical properties to commercial fossil based UPR. After the successful synthesis of the biobased UPs, those were crosslinked with styrene (Sty, the most commonly used monomer, and the influence of the chemical structure of the UPs on the thermomechanical characteristics of UPRs were evaluated. The properties were compared with those of a commercial resin (Resipur 9837©. The BioUPRs presented high gel contents and contact angles that are similar to the commercial resin. The thermomechanical properties were evaluated by dynamic mechanical thermal analysis (DMTA and it was found that the UPR synthesized using propylene glycol (PG, succinic acid (SuAc and itaconic acid (ItAc presented very close thermomechanical properties compared to the commercial resin.

  15. Non-toxic poly(ethylene terephthalate)/clay nanocomposites with enhanced barrier properties

    KAUST Repository

    Hayrapetyan, Suren; Kelarakis, Antonios; Estevez, Luis; Lin, Qin; Dana, Kausik; Chung, Yi-Lin; Giannelis, Emmanuel P.

    2012-01-01

    Motivated by the technological need for poly(ethylene terephthalate) materials with improved barrier properties together with the requirement for sustainability this study focuses on an eco-friendly sulfonated polyester as clay compatibilizer

  16. Enhancing mechanical properties of ceramic papers loaded with zeolites using borate compounds as binders

    OpenAIRE

    Juan P. Cecchini; Ramiro M. Serra; María A. Ulla; Miguel A. Zanuttini; Viviana G. Milt

    2013-01-01

    NaY zeolite-containing ceramic papers were prepared by a papermaking technique with a dual polyelectrolyte retention system that implied the use of cationic and anionic polymers. To improve their mechanical properties, we found that some borate compounds could be successfully used as ceramic binders. Three types of sodium and/or calcium borates were tested as binders: colemanite, nobleite, and anhydrous ulexite. The improvement in the mechanical properties depends both on the borate used and ...

  17. A critical evaluation of the enhancement of mechanical properties of epoxy modified using CNTs

    Science.gov (United States)

    Bedsole, Robert W.; Park, Cheol; Bogert, Philip B.; Tippur, Hareesh V.

    2015-09-01

    Carbon nanotubes (CNTs) have been widely shown in the literature to improve mechanical properties of epoxy, such as tensile strength, elastic modulus, strain to failure, and fracture toughness. These improvements in nanocomposite properties have been attributed to the extraordinary properties of the nanotubes, as well as the quality of their dispersion within and adhesion to the epoxy matrix. However, many authors have also struggled to show significant mechanical improvements using similar methodologies and despite, in some cases, showing qualitative improvements in dispersion with optical microscopy. These authors have frequently resorted to other methods for improving the mechanical properties of CNT/epoxy, such as electrically aligning CNTs, using different types of CNTs, or modifying the stoichiometry. The current work examines many different dispersion techniques, types of CNTs, types of epoxies, curing cycles, and other variables in an attempt to improve the mechanical properties of neat epoxy with CNTs. Despite seeing significant changes in the microscopy, no significant improvements in tensile or fracture properties have been attributed to CNTs in this work.

  18. Supplementation of exogenous adenosine 5'-triphosphate enhances mechanical properties of 3D cell-agarose constructs for cartilage tissue engineering.

    Science.gov (United States)

    Gadjanski, Ivana; Yodmuang, Supansa; Spiller, Kara; Bhumiratana, Sarindr; Vunjak-Novakovic, Gordana

    2013-10-01

    Formation of tissue-engineered cartilage is greatly enhanced by mechanical stimulation. However, direct mechanical stimulation is not always a suitable method, and the utilization of mechanisms underlying mechanotransduction might allow for a highly effective and less aggressive alternate means of stimulation. In particular, the purinergic, adenosine 5'-triphosphate (ATP)-mediated signaling pathway is strongly implicated in mechanotransduction within the articular cartilage. We investigated the effects of transient and continuous exogenous ATP supplementation on mechanical properties of cartilaginous constructs engineered using bovine chondrocytes and human mesenchymal stem cells (hMSCs) encapsulated in an agarose hydrogel. For both cell types, we have observed significant increases in equilibrium and dynamic compressive moduli after transient ATP treatment applied in the fourth week of cultivation. Continuous ATP treatment over 4 weeks of culture only slightly improved the mechanical properties of the constructs, without major changes in the total glycosaminoglycan (GAG) and collagen content. Structure-function analyses showed that transiently ATP-treated constructs, and in particular those based on hMSCs, had the highest level of correlation between compositional and mechanical properties. Transiently treated groups showed intense staining of the territorial matrix for GAGs and collagen type II. These results indicate that transient ATP treatment can improve functional mechanical properties of cartilaginous constructs based on chondrogenic cells and agarose hydrogels, possibly by improving the structural organization of the bulk phase and territorial extracellular matrix (ECM), that is, by increasing correlation slopes between the content of the ECM components (GAG, collagen) and mechanical properties of the construct.

  19. Morphology controlled Y{sub 2}O{sub 3}:Eu{sup 3+} nanophosphors with enhanced photoluminescence properties

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Deepak [School of Physics and Materials Science, Thapar University, Patiala 147003, Punjab (India); Sharma, Manoj, E-mail: manojnarad@sggswu.org [Department of Nanotechnology, Sri Guru Granth Sahib World University, Fatehgarh Sahib 140406, Punjab (India); Pandey, O.P., E-mail: oppandey@thapar.edu [School of Physics and Materials Science, Thapar University, Patiala 147003, Punjab (India)

    2015-02-15

    Eu{sup 3+} doped Y{sub 2}O{sub 3} is prepared by a co-precipitation method using ammonium hydrogen carbonate as precipitating agent. In the present work we studied the effect of different molar concentrations of Poly vinyl pyrrolidone (PVP) and 1-Thio-glycerol (TG) as capping agents to enhance the optical and morphological properties of Y{sub 2}O{sub 3}:Eu{sup 3+} nanophosphors. In addition, variation of pH was studied to control the particle size of the synthesized product. The polymer concentration (TG and PVP) was also optimized at different pH to get higher luminescence of Eu{sup 3+} doped Y{sub 2}O{sub 3} nanoparticles (NPs). It was observed that pH of solution during synthesis and also its concentration affect the morphological and optical properties of Y{sub 2}O{sub 3}:Eu{sup 3+}. The structural, morphological and optical properties were studied by an X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy and photoluminescence spectroscopy. XRD studies followed by Rietveld refinement confirmed the body-centered cubic structure of doped nanophosphors. It was observed that at optimized pH and polymer concentration the nanoparticles of Y{sub 2}O{sub 3}:Eu{sup 3+} have narrow size distribution and exhibited enhanced photoluminescent properties. - highlights: • Nano-sized Y{sub 2}O{sub 3}:Eu{sup 3+} were synthesized by a co-precipitation method using PVP and TG as capping agents. • Effect of polymers (PVP and TG) on morphological properties of Y{sub 2}O{sub 3}:Eu{sup 3+} has been explained in detail. • Improvement in PL intensity for Y{sub 2}O{sub 3}:Eu{sup 3+} prepared with polymers has been explained in detail.

  20. Synergistic effect of cellulose nanocrystals/graphene oxide nanosheets as functional hybrid nanofiller for enhancing properties of PVA nanocomposites.

    Science.gov (United States)

    El Miri, Nassima; El Achaby, Mounir; Fihri, Aziz; Larzek, Mohamed; Zahouily, Mohamed; Abdelouahdi, Karima; Barakat, Abdellatif; Solhy, Abderrahim

    2016-02-10

    Novel functional hybrid nanofillers composed of cellulose nanocrystals (CNC) and graphene oxide nanosheets (GON), at different weight ratios (2:1, 1:1 and 1:2), were successfully prepared and characterized, and their synergistic effect in enhancing the properties of poly(vinyl alcohol) (PVA) nanocomposites was investigated. Due to the synergistic reinforcement, it was found that the Young's modulus, tensile strength and toughness of the PVA nanocomposite containing 5 wt% hybrid nanofiller (1:2) were significantly improved by 320%, 124% and 159%, respectively; and the elongation at break basically remained compared to the neat PVA matrix. In addition, the glass and melting temperatures as well as the moisture sorption of nanocomposites were also enhanced. This synergistic effect improved the dispersion homogeneity by avoiding the agglomeration phenomenon of nanofillers within the polymer matrix, resulting in nanocomposites with largely enhanced properties compared to those prepared from single nanofiller (CNC or GON). The preparation of these hybrid nanofillers and their incorporation into a polymer provided a novel method for the development of novel multifunctional nanocomposites based on the combination of existing nanomaterials. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Effects of low-temperature pretreatment on enhancing properties of refuse-derived fuel via microwave irradiation.

    Science.gov (United States)

    Liu, Zhen; Wang, Han-Qing; Zhou, Yue-Yun; Zhang, Xiao-Dong; Liu, Jian-Wen

    2017-07-01

    The present study focuses on pretreatment of enhancing the properties of refuse-derived fuel (RDF) via low-temperature microwave irradiation. These improved properties include lower chlorine content, a more porous surface structure and better combustion characteristics. In this study, low-temperature microwave irradiation was carried out in a modified microwave apparatus and the range of temperature was set to be 220-300℃. We found that the microwave absorbability of RDF was enhanced after being partly carbonized. Moreover, with the increasing of the final temperature, the organochlorine removal ratio was greatly increased to 80% and the content of chlorine was dramatically decreased to an extremely low level. It was also interesting to find that the chlorine of RDF was mainly released as HCl rather than organic chloride volatiles. The finding is just the same as the polyvinyl chloride pyrolysis process. In addition, pores and channels emerged during the modifying operation and the modified RDF has better combustibility and combustion stability than traditional RDF. This work revealed that low-temperature modification of RDF via microwave irradiation is significant for enhancing the quality of RDF and avoiding HCl erosion of equipment substantially.

  2. Enhancing Hydrogen Diffusion in Silica Matrix by Using Metal Ion Implantation to Improve the Emission Properties of Silicon Nanocrystals

    Directory of Open Access Journals (Sweden)

    J. Bornacelli

    2014-01-01

    Full Text Available Efficient silicon-based light emitters continue to be a challenge. A great effort has been made in photonics to modify silicon in order to enhance its light emission properties. In this aspect silicon nanocrystals (Si-NCs have become the main building block of silicon photonic (modulators, waveguide, source, and detectors. In this work, we present an approach based on implantation of Ag (or Au ions and a proper thermal annealing in order to improve the photoluminescence (PL emission of Si-NCs embedded in SiO2. The Si-NCs are obtained by ion implantation at MeV energy and nucleated at high depth into the silica matrix (1-2 μm under surface. Once Si-NCs are formed inside the SiO2 we implant metal ions at energies that do not damage the Si-NCs. We have observed by, PL and time-resolved PL, that ion metal implantation and a subsequent thermal annealing in a hydrogen-containing atmosphere could significantly increase the emission properties of Si-NCs. Elastic Recoil Detection measurements show that the samples with an enhanced luminescence emission present a higher hydrogen concentration. This suggests that ion metal implantation enhances the hydrogen diffusion into silica matrix allowing a better passivation of surface defects on Si NCs.

  3. Pentiptycene-based polyurethane with enhanced mechanical properties and CO2-plasticization resistance for thin film gas separation membranes.

    Science.gov (United States)

    Pournaghshband Isfahani, Ali; Sadeghi, Morteza; Wakimoto, Kazuki; Shrestha, Binod Babu; Bagheri, Rouhollah; Sivaniah, Easan; Ghalei, Behnam

    2018-04-30

    Development of thin film composite (TFC) membranes offers an opportunity to achieve the permeability/selectivity requirements for optimum CO2 separation performance. However, the durability and performance of thin film gas separation membranes are mostly challenged by weak mechanical properties and high CO2 plasticization. Here, we designed new polyurethane (PU) structures with bulky aromatic chain extenders that afford preferred mechanical properties for ultra-thin film formation. An improvement of about 1500% in Young's modulus and 600% in hardness was observed for pentiptycene-based PUs compared to typical PU membranes. Single (CO2, H2, CH4, and N2) and mixed (CO2/N2 and CO2/CH4) gas permeability tests were performed on the PU membranes. The resulting TFC membranes showed a high CO2 permeance up to 1400 GPU (10-6 cm3(STP) cm-2s-1 cmHg-1) and the CO2/N2 and CO2/H2 selectivities of about 22 and 2.1, respectively. The enhanced mechanical properties of pentiptycene-based PUs results in high performance thin membranes with the similar selectivity of the bulk polymer. The thin film membranes prepared from pentiptycene-based PUs also showed a two-fold enhanced plasticization resistance compared to non-pentiptycene containing PU membranes.

  4. Enhanced mechanical, thermal and antimicrobial properties of poly(vinyl alcohol)/graphene oxide/starch/silver nanocomposites films.

    Science.gov (United States)

    Usman, Adil; Hussain, Zakir; Riaz, Asim; Khan, Ahmad Nawaz

    2016-11-20

    In the present work, synthesis of poly(vinyl alcohol)/graphene oxide/starch/silver (PVA/GO/Starch/Ag) nanocomposites films is reported. Such films have been characterized and investigated for their mechanical, thermal and antimicrobial properties. The exfoliation of GO in the PVA matrix occurs owing to the non-covalent interactions of the polymer chains of PVA and hydrophilic surface of the GO layers. Presence of GO in PVA and PVA/starch blends were found to enhance the tensile strength of the nanocomposites system. It was found that the thermal stability of PVA as well as PVA/starch blend systems increased by the incorporation of GO where strong physical bonding between GO layers and PVA/starch blends is assumed to cause thermal barrier effects. Antimicrobial properties of the prepared films were investigated against Escherichia coli and Staphylococcus aureus. Our results show enhanced antimicrobial properties of the prepared films where PVA-GO, PVA-Ag, PVA-GO-Ag and PVA-GO-Ag-Starch showed antimicrobial activity in ascending order. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Impact strength and flexural properties enhancement of methacrylate silane treated oil palm mesocarp fiber reinforced biodegradable hybrid composites.

    Science.gov (United States)

    Eng, Chern Chiet; Ibrahim, Nor Azowa; Zainuddin, Norhazlin; Ariffin, Hidayah; Yunus, Wan Md Zin Wan

    2014-01-01

    Natural fiber as reinforcement filler in polymer composites is an attractive approach due to being fully biodegradable and cheap. However, incompatibility between hydrophilic natural fiber and hydrophobic polymer matrix restricts the application. The current studies focus on the effects of incorporation of silane treated OPMF into polylactic acid (PLA)/polycaprolactone (PCL)/nanoclay/OPMF hybrid composites. The composites were prepared by melt blending technique and characterize the composites with Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). FTIR spectra indicated that peak shifting occurs when silane treated OPMF was incorporated into hybrid composites. Based on mechanical properties results, incorporation of silane treated OPMF enhances the mechanical properties of unmodified OPMF hybrid composites with the enhancement of flexural and impact strength being 17.60% and 48.43%, respectively, at 10% fiber loading. TGA thermogram shows that incorporation of silane treated OPMF did not show increment in thermal properties of hybrid composites. SEM micrographs revealed that silane treated OPMF hybrid composites show good fiber/matrix adhesion as fiber is still embedded in the matrix and no cavity is present on the surface. Water absorption test shows that addition of less hydrophilic silane treated OPMF successfully reduces the water uptake of hybrid composites.

  6. A nano-sandwich construct built with graphene nanosheets and carbon nanotubes enhances mechanical properties of hydroxyapatite-polyetheretherketone scaffolds.

    Science.gov (United States)

    Feng, Pei; Peng, Shuping; Wu, Ping; Gao, Chengde; Huang, Wei; Deng, Youwen; Xiao, Tao; Shuai, Cijun

    2016-01-01

    A nano-sandwich construct was built by combining two-dimensional graphene nanosheets (GNSs) and one-dimensional carbon nanotubes (CNTs) to improve the mechanical properties of hydroxyapatite-polyetheretherketone (HAP-PEEK) scaffolds for bone tissue engineering. In this nano-sandwich construct, the long tubular CNTs penetrated the interlayers of graphene and prevented their aggregation, increasing the effective contact area between the construct and matrix. The combination of GNSs and CNTs in a weight ratio of 2:8 facilitated the dispersion of each other and provided a synergetic effect in enhancing the mechanical properties. The compressive strength and modulus of the scaffolds were increased by 63.58% and 56.54% at this time compared with those of HAP-PEEK scaffolds, respectively. The carbon-based fillers, pulling out and bridging, were also clearly observed in the matrix. Moreover, the dangling of CNTs and their entangling with GNSs further reinforced the mechanical properties. Furthermore, apatite layer formed on the scaffold surface after immersing in simulated body fluid, and the cells attached and spread well on the surface of the scaffolds and displayed good viability, proliferation, and differentiation. These evidence indicate that the HAP-PEEK scaffolds enhanced by GNSs and CNTs are a promising alternative for bone tissue engineering.

  7. Enhanced superconducting properties of MgB2 by carbon substitution using carbon containing nano additives

    International Nuclear Information System (INIS)

    Devadas, K.M.; Varghese, Neson; Vinod, K.; Rahul, S.; Thomas, Syju; Anooja, J.B.; Syamaprasad, U.; Sundaresan, A.; Roy, S.B.

    2010-01-01

    A comparative study on the effect of doping of nano carbon, nano diamond and nano SiC in MgB 2 is carried out. The J c (H) is significantly enhanced for all doped samples compared to the pure sample among which MgB 1.9 C 0.1 (nano C) exhibits the best J c (H) performance. The enhanced performance is due to the effective substitution of C at B site which is confirmed by the systematic decrease in both α axis and T c . (author)

  8. Metal-organic frameworks at interfaces of hybrid perovskite solar cells for enhanced photovoltaic properties.

    Science.gov (United States)

    Shen, Deli; Pang, Aiying; Li, Yafeng; Dou, Jie; Wei, Mingdeng

    2018-01-31

    In this study, metal-organic frameworks, as an interfacial layer, were introduced into perovskite solar cells (PSCs) for the first time. An interface modified with the metal-organic framework ZIF-8 efficiently enhanced perovskite crystallinity and grain sizes, and the photovoltaic performance of the PSCs was significantly improved, resulting in a maximum PCE of 16.99%.

  9. Enhancement of mechanical properties and interfacial adhesion by chemical odification of natural fibre reinforced polypropylene composites

    CSIR Research Space (South Africa)

    Erasmus, E

    2008-11-01

    Full Text Available with the polymer matrix. Therefore, the constituents need to be chemically modified to enhancing adhesion between fibre and polymer matrix. The aim of this work is to improve the interfacial adhesion between the polypropylene matrix and the natural fibre...

  10. Neuroprotective and memory enhancing properties of a dual agonist of the FGF receptor and NCAM

    DEFF Research Database (Denmark)

    Enevoldsen, Maj N; Kochoyan, Artur; Jurgenson, Monika

    2012-01-01

    subcutaneous administration, enhances long-term memory in normal mice and ameliorates memory deficit in mice with induced brain inflammation. Moreover, Enreptin reduces cognitive impairment and neuronal death induced by Aß25-35 in a rat model of Alzheimer's disease, and reduces the mortality rate and clinical...

  11. Transmission Property of Directly Modulated Signals Enhanced by a Micro-ring Resonator

    DEFF Research Database (Denmark)

    An, Yi; Lorences Riesgo, Abel; Seoane, Jorge

    2012-01-01

    A silicon micro-ring resonator is used to enhance the modulation speed of a 10-Gbit/s directly modulated laser to 40 Gbit/s. The generated signal is transmitted error free over 4.5 km SSMF. Dispersion tolerance is also studied....

  12. Enhancement of Nutritional and Antioxidant Properties of Peanut Meal by Bio-modification with Bacillus licheniformis.

    Science.gov (United States)

    Yang, Xinjian; Teng, Da; Wang, Xiumin; Guan, Qingfeng; Mao, Ruoyu; Hao, Ya; Wang, Jianhua

    2016-11-01

    Peanut meal (PM) is limited in practical use (feed or food) from imbalance of amino acid profile and denaturation of protein. Fermentation was used to promote its nutritional and functional properties by single-factor experiments and orthogonal experiments. Results showed that the nutritional properties of fermented peanut meal (crude protein content, dry matter content, ash content, acid soluble oligopeptides content, in vitro digestibility, and content of organic acids) had a significant increase (P implied that the nutritional and antioxidant properties of peanut meal were improved effectively by biological modification, which could be valuable in terms of nutrition and protein resources. It is great of importance to meet requirement of raw materials for husbandry in China when facing a huge lacking of feedstuff, especially for protein feed with an over 80 % import amount depending from other countries yearly.

  13. Enhancement of thermoelectric properties of Mg2Si compounds with Bi doping through carrier concentration tuning

    Science.gov (United States)

    Lee, Ji Eun; Cho, Sang-Hum; Oh, Min-Wook; Ryu, Byungi; Joo, Sung-Jae; Kim, Bong-Seo; Min, Bok-Ki; Lee, Hee-Woong; Park, Su-Dong

    2014-07-01

    The Bi-doped Mg2Si powder was fabricated with solid state reaction method and consolidated with hot pressing method and then its thermoelectric properties were investigated. The n-type transport properties were measured in all samples and temperature dependence of the electrical properties shows a behavior of degenerate semiconductors for Bi-doped samples. The electrical resistivity and the Seebeck coefficient were greatly reduced with Bi, which was mainly due to the increment of the carrier concentration. The samples have maximum carrier concentration of 8.2 × 1018 cm-3. The largest ZT value of 0.61 was achieve at 873 K for Mg2.04SiBi0.02. The Bi-doping was found to be an effective n-type dopant to adjust carrier concentration. [Figure not available: see fulltext.

  14. CEMCAN Software Enhanced for Predicting the Properties of Woven Ceramic Matrix Composites

    Science.gov (United States)

    Murthy, Pappu L. N.; Mital, Subodh K.; DiCarlo, James A.

    2000-01-01

    Major advancements are needed in current high-temperature materials to meet the requirements of future space and aeropropulsion structural components. Ceramic matrix composites (CMC's) are one class of materials that are being evaluated as candidate materials for many high-temperature applications. Past efforts to improve the performance of CMC's focused primarily on improving the properties of the fiber, interfacial coatings, and matrix constituents as individual phases. Design and analysis tools must take into consideration the complex geometries, microstructures, and fabrication processes involved in these composites and must allow the composite properties to be tailored for optimum performance. Major accomplishments during the past year include the development and inclusion of woven CMC micromechanics methodology into the CEMCAN (Ceramic Matrix Composites Analyzer) computer code. The code enables one to calibrate a consistent set of constituent properties as a function of temperature with the aid of experimentally measured data.

  15. Fe3O4 nanoparticles decorated MWCNTs @ C ferrite nanocomposites and their enhanced microwave absorption properties

    Science.gov (United States)

    Zhang, Kaichuang; Gao, Xinbao; Zhang, Qian; Chen, Hao; Chen, Xuefang

    2018-04-01

    Fe3O4 nanoparticles decorated MWCNTs @ C ferrite nanocomposites were synthesized using a co-precipitation method and a calcination process. As one kind absorbing material, we researched the electromagnetic absorption properties of the composites that were mixed with a filler loading of 80 wt% paraffin. In addition, we studied the influence of the magnetic nanoparticle content on the absorbing properties. The results showed that the frequency corresponding to the maximum absorptions shifted to lower frequency when the magnetic nanoparticles content increased. The Fe3O4 nanoparticles decorated MWCNTs @ C ferrite nanocomposites with approximately 60% Fe3O4 nanoparticles showed the best electromagnetic absorption properties. The maximum reflection loss was -52.47 dB with a thickness of 2.0 mm at 10.4 GHz.

  16. Preparation and characterization of molten salt based nanothermic fluids with enhanced thermal properties for solar thermal applications

    International Nuclear Information System (INIS)

    Madathil, Pramod Kandoth; Balagi, Nagaraj; Saha, Priyanka; Bharali, Jitalaxmi; Rao, Peddy V.C.; Choudary, Nettem V.; Ramesh, Kanaparthi

    2016-01-01

    Highlights: • Prepared and characterized inorganic ternary molten salt based nanothermic fluids. • MoS_2 and CuO nanoparticles incorporated ternary molten salts have been prepared. • Thermal properties enhanced by the addition of MoS_2 and CuO nanoparticles. • The amount of nanoparticles has been optimized. - Abstract: In the current energy scenario, solar energy is attracting considerable attention as a renewable energy source with ample research and commercial opportunities. The novel and efficient technologies in the solar energy are directed to develop methods for solar energy capture, storage and utilization. High temperature thermal energy storage systems can deal with a wide range of temperatures and therefore they are highly recommended for concentrated solar power (CSP) applications. In the present study, a systematic investigation has been carried out to identify the suitable inorganic nanoparticles and their addition in the molten salt has been optimized. In order to enhance the thermo-physical properties such as thermal conductivity and specific heat capacity of molten salt based HTFs, we report the utilization of MoS_2 and CuO nanoparticles. The enhancement in the above mentioned thermo-physical properties has been demonstrated for optimized compositions and the morphologies of nanoparticle-incorporated molten salts have been studied by scanning electron microscopy (SEM). Nanoparticle addition to molten salts is an efficient method to prepare thermally stable molten salt based heat transfer fluids which can be used in CSP plants. It is also observed that the sedimentation of nanoparticles in molten salt is negligible compared to that in organic heat transfer fluids.

  17. Property enhancement by grain refinement of zinc-aluminium foundry alloys

    International Nuclear Information System (INIS)

    Krajewski, W K; Piwowarski, G; Krajewski, P K; Greer, A L

    2016-01-01

    Development of cast alloys with good mechanical properties and involving less energy consumption during their melting is one of the key demands of today's industry. Zinc foundry alloys of high and medium Al content, i.e. Zn-(15-30) wt.% Al and Zn-(8-12) wt.% Al, can satisfy these requirements. The present paper summarizes the work [1-9] on improving properties of sand-cast ZnAl10 (Zn-10 wt.% Al) and ZnAl25 (Zn-25 wt. % Al) alloys by melt inoculation. Special attention was devoted to improving ductility, whilst preserving high damping properties at the same time. The composition and structural modification of medium- and high-aluminium zinc alloys influence their strength, tribological properties and structural stability. In a series of studies, Zn - (10-12) wt. % Al and Zn - (25-26) wt.% Al - (1-2.5) wt.% Cu alloys have been doped with different levels of added Ti. The melted alloys were inoculated with ZnTi-based refiners and it was observed that the dendritic structure is significantly finer already after addition of 50 - 100 ppm Ti to the melted alloys. The alloy's structure and mechanical properties have been studied using: SEM (scanning electron microscopy), LM (light microscopy), dilatometry, pin-on-disc wear, and tensile strength measurements. Grain refinement leads to significant improvement of ductility in the binary high-aluminium Zn-(25-27) Al alloys while in the medium-aluminium alloys the effect is rather weak. In the ternary alloys Zn-26Al-Cu, replacing a part of Cu with Ti allows dimensional changes to be reduced while preserving good tribological properties. Furthermore, the high initial damping properties were nearly entirely preserved after inoculation. The results obtained allow us to characterize grain refinement of the examined high-aluminium zinc alloys as a promising process leading to the improvement of their properties. At the same time, using low melting ZnTi-based master alloys makes it possible to avoid the excessive melt

  18. Properties of Ground Level Enhancement Events and the Associated Solar Eruptions During Solar Cycle 23

    Science.gov (United States)

    Gopalswamy, N.; Xie, H.; Yashiro, S.; Akiyama, S.; Makela, P.; Usokin, I. G.

    2012-01-01

    Solar cycle 23 witnessed the most complete set of observations of coronal mass ejections (CMEs) associated with the Ground Level Enhancement (GLE) events. We present an overview of the observed properties of the GLEs and those of the two associated phenomena, viz., flares and CMEs, both being potential sources of particle acceleration. Although we do not find a striking correlation between the GLE intensity and the parameters of flares and CMEs, the solar eruptions are very intense involving X-class flares and extreme CME speeds (average approx. 2000 km/s). An M7.1 flare and a 1200 km/s CME are the weakest events in the list of 16 GLE events. Most (80 %) of the CMEs are full halos with the three non-halos having widths in the range 167 to 212 degrees. The active regions in which the GLE events originate are generally large: 1290 msh (median 1010 msh) compared to 934 msh (median: 790 msh) for SEP-producing active regions. For accurate estimation of the CME height at the time of metric type II onset and GLE particle release, we estimated the initial acceleration of the CMEs using flare and CME observations. The initial acceleration of GLE-associated CMEs is much larger (by a factor of 2) than that of ordinary CMEs (2.3 km/sq s vs. 1 km/sq s). We confirmed the initial acceleration for two events for which CME measurements are available in the inner corona. The GLE particle release is delayed with respect to the onset of all electromagnetic signatures of the eruptions: type II bursts, low frequency type III bursts, soft X-ray flares and CMEs. The presence of metric type II radio bursts some 17 min (median: 16 min; range: 3 to 48 min) before the GLE onset indicates shock formation well before the particle release. The release of GLE particles occurs when the CMEs reach an average height of approx 3.09 R(sub s) (median: 3.18 R (sub s) ; range: 1.71 to 4.01 R (sub s) ) for well-connected events (source longitude in the range W20–W90). For poorly connected events, the

  19. Enhancement of surface mechanical properties by using TiN[BCN/BN]{sub n}/c-BN multilayer system

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, H. [Laboratorio de Recubrimientos Duros, CDT-ASTIN SENA, Cali (Colombia); Caicedo, J.C., E-mail: Jcesarca@calima.univalle.edu.co [Grupo de Peliculas Delgadas, Universidad del Valle, Cali (Colombia); Amaya, C. [Grupo de Peliculas Delgadas, Universidad del Valle, Cali (Colombia); Munoz-Saldana, J. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Queretaro, Mexico (Mexico); Yate, L.; Esteve, J. [Department de Fisica Aplicada i Optica, Universitat de Barcelona, Catalunya (Spain); Prieto, P. [Grupo de Peliculas Delgadas, Universidad del Valle, Cali (Colombia); Centro de Excelencia en Nuevos Materiales, CENM, Cali (Colombia)

    2010-11-15

    The aim of this work is to improve the mechanical properties of AISI 4140 steel substrates by using a TiN[BCN/BN]{sub n}/c-BN multilayer system as a protective coating. TiN[BCN/BN]{sub n}/c-BN multilayered coatings via reactive r.f. magnetron sputtering technique were grown, systematically varying the length period ({Lambda}) and the number of bilayers (n) because one bilayer (n = 1) represents two different layers (t{sub BCN} + t{sub BN}), thus the total thickness of the coating and all other growth parameters were maintained constant. The coatings were characterized by Fourier transform infrared spectroscopy showing bands associated with h-BN bonds and c-BN stretching vibrations centered at 1400 cm{sup -1} and 1100 cm{sup -1}, respectively. Coating composition and multilayer modulation were studied via secondary ion mass spectroscopy. Atomic force microscopy analysis revealed a reduction in grain size and roughness when the bilayer number (n) increased and the bilayer period decreased. Finally, enhancement of mechanical properties was determined via nanoindentation measurements. The best behavior was obtained when the bilayer period ({Lambda}) was 80 nm (n = 25), yielding the relative highest hardness ({approx}30 GPa) and elastic modulus (230 GPa). The values for the hardness and elastic modulus are 1.5 and 1.7 times greater than the coating with n = 1, respectively. The enhancement effects in multilayered coatings could be attributed to different mechanisms for layer formation with nanometric thickness due to the Hall-Petch effect; because this effect, originally used to explain increased hardness with decreasing grain size in bulk polycrystalline metals, has also been used to explain hardness enhancements in multilayered coatings taking into account the thickness reduction at individual single layers that make up the multilayered system. The Hall-Petch model based on dislocation motion within layered and across layer interfaces has been successfully applied to

  20. Enhancement of surface mechanical properties by using TiN[BCN/BN] n/c-BN multilayer system

    Science.gov (United States)

    Moreno, H.; Caicedo, J. C.; Amaya, C.; Muñoz-Saldaña, J.; Yate, L.; Esteve, J.; Prieto, P.

    2010-11-01

    The aim of this work is to improve the mechanical properties of AISI 4140 steel substrates by using a TiN[BCN/BN] n/c-BN multilayer system as a protective coating. TiN[BCN/BN] n/c-BN multilayered coatings via reactive r.f. magnetron sputtering technique were grown, systematically varying the length period ( Λ) and the number of bilayers ( n) because one bilayer ( n = 1) represents two different layers ( tBCN + tBN), thus the total thickness of the coating and all other growth parameters were maintained constant. The coatings were characterized by Fourier transform infrared spectroscopy showing bands associated with h-BN bonds and c-BN stretching vibrations centered at 1400 cm -1 and 1100 cm -1, respectively. Coating composition and multilayer modulation were studied via secondary ion mass spectroscopy. Atomic force microscopy analysis revealed a reduction in grain size and roughness when the bilayer number ( n) increased and the bilayer period decreased. Finally, enhancement of mechanical properties was determined via nanoindentation measurements. The best behavior was obtained when the bilayer period ( Λ) was 80 nm ( n = 25), yielding the relative highest hardness (˜30 GPa) and elastic modulus (230 GPa). The values for the hardness and elastic modulus are 1.5 and 1.7 times greater than the coating with n = 1, respectively. The enhancement effects in multilayered coatings could be attributed to different mechanisms for layer formation with nanometric thickness due to the Hall-Petch effect; because this effect, originally used to explain increased hardness with decreasing grain size in bulk polycrystalline metals, has also been used to explain hardness enhancements in multilayered coatings taking into account the thickness reduction at individual single layers that make up the multilayered system. The Hall-Petch model based on dislocation motion within layered and across layer interfaces has been successfully applied to multilayered coatings to explain this

  1. Enhancement of surface mechanical properties by using TiN[BCN/BN]n/c-BN multilayer system

    International Nuclear Information System (INIS)

    Moreno, H.; Caicedo, J.C.; Amaya, C.; Munoz-Saldana, J.; Yate, L.; Esteve, J.; Prieto, P.

    2010-01-01

    The aim of this work is to improve the mechanical properties of AISI 4140 steel substrates by using a TiN[BCN/BN] n /c-BN multilayer system as a protective coating. TiN[BCN/BN] n /c-BN multilayered coatings via reactive r.f. magnetron sputtering technique were grown, systematically varying the length period (Λ) and the number of bilayers (n) because one bilayer (n = 1) represents two different layers (t BCN + t BN ), thus the total thickness of the coating and all other growth parameters were maintained constant. The coatings were characterized by Fourier transform infrared spectroscopy showing bands associated with h-BN bonds and c-BN stretching vibrations centered at 1400 cm -1 and 1100 cm -1 , respectively. Coating composition and multilayer modulation were studied via secondary ion mass spectroscopy. Atomic force microscopy analysis revealed a reduction in grain size and roughness when the bilayer number (n) increased and the bilayer period decreased. Finally, enhancement of mechanical properties was determined via nanoindentation measurements. The best behavior was obtained when the bilayer period (Λ) was 80 nm (n = 25), yielding the relative highest hardness (∼30 GPa) and elastic modulus (230 GPa). The values for the hardness and elastic modulus are 1.5 and 1.7 times greater than the coating with n = 1, respectively. The enhancement effects in multilayered coatings could be attributed to different mechanisms for layer formation with nanometric thickness due to the Hall-Petch effect; because this effect, originally used to explain increased hardness with decreasing grain size in bulk polycrystalline metals, has also been used to explain hardness enhancements in multilayered coatings taking into account the thickness reduction at individual single layers that make up the multilayered system. The Hall-Petch model based on dislocation motion within layered and across layer interfaces has been successfully applied to multilayered coatings to explain this

  2. Enhanced protective properties of epoxy/polyaniline-camphorsulfonate nanocomposite coating on an ultrafine-grained metallic surface

    Science.gov (United States)

    Pour-Ali, Sadegh; Kiani-Rashid, Alireza; Babakhani, Abolfazl; Davoodi, Ali

    2016-07-01

    An ultrafine-grained surface layer on mild steel substrate with average grain size of 77 nm was produced through wire brushing process. Surface grain size was determined through transmission electron microscopy and X-ray diffraction methods. This substrate was coated with epoxy and an in situ synthesized epoxy/polyaniline-camphorsulfonate (epoxy/PANI-CSA) nanocomposite. The corrosion behavior was studied by open circuit potential, potentiodynamic polarization and impedance measurements. Results of electrochemical tests evidenced the enhanced protective properties of epoxy/PANI-CSA coating on the substrate with ultrafine-grained surface.

  3. Method of producing an item with enhanced wetting properties by fast replication and replication tool used in the method

    DEFF Research Database (Denmark)

    2016-01-01

    , 2b) comprises a microscale structured master surface (3a, 3b, 3c) having a lateral master pattern and a vertical master profile. The microscale structured master surface (3a, 3b, 3c) has been provided by localized pulsed laser treatment to generate microscale phase explosions. A method of producing...... an item with enhanced wetting properties uses the replication tool (1) to form an item (4) with a general shape as defined by the tool surface. The formed item (4) comprises a microscale textured replica surface (5a, 5b, 5c) with a lateral arrangement of polydisperse microscale protrusions....

  4. Application of transglycosylated stevia and hesperidin as drug carriers to enhance biopharmaceutical properties of poorly-soluble artemisinin.

    Science.gov (United States)

    Letchmanan, Kumaran; Shen, Shou-Cang; Ng, Wai Kiong; Tan, Reginald B H

    2018-01-01

    Biopharmaceutical properties of poorly water-soluble antimalarial drug, Artemisinin (ART), were improved by formulating amorphous solid dispersions with transglycosylated food additives (Hsp-G and Stevia-G) via co-spray drying. Both the formulated ART/Hsp-G and ART/Stevia-G showed superior dissolution properties with a burst release of more than 95% of drug within 5 min, whereas untreated ART dissolved only 4% in 5min. The supersaturation solubility of the formulated ART was enhanced by 2-fold as compared with untreated counterpart. The storage stability tests indicated that these formulations chemically stable at room temperature and under low humidity (water-soluble ART. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Semi-Degradable Poly(β-amino ester) Networks with Temporally-Controlled Enhancement of Mechanical Properties

    Science.gov (United States)

    Safranski, David L.; Weiss, Daiana; Clark, J. Brian; Taylor, W.R.; Gall, Ken

    2014-01-01

    Biodegradable polymers are clinically used in numerous biomedical applications, and classically show a loss in mechanical properties within weeks of implantation. This work demonstrates a new class of semi-degradable polymers that show an increase in mechanical properties through degradation via a controlled shift in a thermal transition. Semi-degradable polymer networks, poly(β-amino ester)-co-methyl methacrylate, were formed from a low glass transition temperature crosslinker, poly(β-amino ester), and high glass transition temperature monomer, methyl methacrylate, which degraded in a manner dependent upon the crosslinker chemical structure. In vitro and in vivo degradation revealed changes in mechanical behavior due to the degradation of the crosslinker from the polymer network. This novel polymer system demonstrates a strategy to temporally control the mechanical behavior of polymers and to enhance the initial performance of smart biomedical devices. PMID:24769113

  6. Nanostructure and optical properties of CeO{sub 2} thin films obtained by plasma-enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Barreca, D.; Bruno, G.; Gasparotto, A.; Losurdo, M.; Tondello, E

    2003-12-15

    In the present study, Spectroscopic Ellipsometry (SE) is used to investigate the interrelations between nanostructure and optical properties of CeO{sub 2} thin films deposited by Plasma-Enhanced Chemical Vapor Deposition (PE-CVD). The layers were synthesized in Ar and Ar-O{sub 2} plasmas on Si(100) substrates at temperatures lower than 300 deg. C. Both the real and imaginary parts of the complex dielectric functions and, subsequently, the optical constants of the films are derived up to 6.0 eV photon energy. Particular attention is devoted to the influence of synthesis conditions and sample properties on the optical response, taking into account the effects of surface roughness and SiO{sub 2} interface layer on Si.

  7. Design of Xylose-Based Semisynthetic Polyurethane Tissue Adhesives with Enhanced Bioactivity Properties.

    Science.gov (United States)

    Balcioglu, Sevgi; Parlakpinar, Hakan; Vardi, Nigar; Denkbas, Emir Baki; Karaaslan, Merve Goksin; Gulgen, Selam; Taslidere, Elif; Koytepe, Suleyman; Ates, Burhan

    2016-02-01

    Developing biocompatible tissue adhesives with high adhesion properties is a highly desired goal of the tissue engineering due to adverse effects of the sutures. Therefore, our work involves synthesis, characterization, adhesion properties, protein adsorption, in vitro biodegradation, in vitro and in vivo biocompatibility properties of xylose-based semisynthetic polyurethane (NPU-PEG-X) bioadhesives. Xylose-based semisynthetic polyurethanes were developed by the reaction among 4,4'-methylenebis(cyclohexyl isocyanate) (MCI), xylose and polyethylene glycol 200 (PEG). Synthesized polyurethanes (PUs) showed good thermal stability and high adhesion strength. The highest values in adhesion strength were measured as 415.0 ± 48.8 and 94.0 ± 2.8 kPa for aluminum substrate and muscle tissue in 15% xylose containing PUs (NPU-PEG-X-15%), respectively. The biodegradation of NPU-PEG-X-15% was also determined as 19.96 ± 1.04% after 8 weeks of incubation. Relative cell viability of xylose containing PU was above 86%. Moreover, 10% xylose containing NPU-PEG-X (NPU-PEG-X-10%) sample has favorable tissue response, and inflammatory reaction between 1 and 6 weeks implantation period. With high adhesiveness and biocompatibility properties, NPU-PEG-X can be used in the medical field as supporting materials for preventing the fluid leakage after abdominal surgery or wound closure.

  8. Enhanced mechanical properties of 1,3-trimethylene carbonate polymers and networks

    NARCIS (Netherlands)

    Pêgo, A.P.; Grijpma, Dirk W.; Feijen, Jan

    2003-01-01

    Poly(1,3-trimethylene carbonate), poly(TMC), has often been regarded as a rubbery polymer that cannot be applied in the biomedical field due to its poor dimensional stability, tackiness and inadequate mechanical properties. In this study we show that high molecular weight, amorphous poly(TMC) is

  9. Significant Enhancement of Mechanical and Thermal Properties of Thermoplastic Polyester Elastomer by Polymer Blending and Nanoinclusion

    Directory of Open Access Journals (Sweden)

    Manwar Hussain

    2016-01-01

    Full Text Available Thermoplastic elastomer composites and nanocomposites were fabricated via melt processing technique by blending thermoplastic elastomer (TPEE with poly(butylene terephthalate (PBT thermoplastic and also by adding small amount of organ