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Sample records for cd19 complex formation

  1. Immunotherapy of B-Cell Lymphoma with an Engineered Bispecific Antibody Targeting CD19 and CD5

    Directory of Open Access Journals (Sweden)

    Frank Breitling

    2013-05-01

    Full Text Available Using genetic engineering a humanized Fab fragment with specificity for CD19 was fused to a disulfide-stabilized single-chain antibody (dsFv recognizing CD5. This format should show reduced immunogenicity and improved tissue penetration. The specificity of bsAb FabCD19xdsFvCD5 binding to target cells was verified by flow cytometry on B and T lymphoma cell lines. Binding affinities of both arms were compared with the bivalent parental antibodies against CD19 and CD5 by binding competition assay. Redirected lysis of B lymphoma cells by preactivated PBMC from healthy donors was demonstrated in a chromium-release assay. A clear dose-response relationship could be established in the range from 1 ng/mL to 10 mg/mL bsAb. To evaluate the in vivo efficacy of bsAb FabCD19xdsFvCD5, NOD/SCID mice were intravenously injected with luciferase transfected Raji lymphoma cells together with pre-activated PBMC. Mice received five injections of therapeutic bsAb or control antibodies. While in the control groups all mice died within 40 to 50 days, 40% of bsAb treated animals survived longer than 60 days.

  2. Complexity of formation in holography

    Science.gov (United States)

    Chapman, Shira; Marrochio, Hugo; Myers, Robert C.

    2017-01-01

    It was recently conjectured that the quantum complexity of a holographic boundary state can be computed by evaluating the gravitational action on a bulk region known as the Wheeler-DeWitt patch. We apply this complexity=action duality to evaluate the `complexity of formation' [1, 2], i.e. the additional complexity arising in preparing the entangled thermofield double state with two copies of the boundary CFT compared to preparing the individual vacuum states of the two copies. We find that for boundary dimensions d > 2, the difference in the complexities grows linearly with the thermal entropy at high temperatures. For the special case d = 2, the complexity of formation is a fixed constant, independent of the temperature. We compare these results to those found using the complexity=volume duality.

  3. Complexity of Formation in Holography

    CERN Document Server

    Chapman, Shira; Myers, Robert C

    2016-01-01

    It was recently conjectured that the quantum complexity of a holographic boundary state can be computed by evaluating the gravitational action on a bulk region known as the Wheeler-DeWitt patch. We apply this complexity=action duality to evaluate the `complexity of formation' (arXiv:1509.07876, arXiv:1512.04993), i.e., the additional complexity arising in preparing the entangled thermofield double state with two copies of the boundary CFT compared to preparing the individual vacuum states of the two copies. We find that for boundary dimensions $d>2$, the difference in the complexities grows linearly with the thermal entropy at high temperatures. For the special case $d=2$, the complexity of formation is a fixed constant, independent of the temperature. We compare these results to those found using the complexity=volume duality.

  4. Compulsory formation of solvento complexes

    Energy Technology Data Exchange (ETDEWEB)

    Kukushkin, Yu.N.; Kukushkin, V.Yu.

    1986-01-01

    The essence of the method of the compulsory formation of solvated complexes which are labile in substitution reactions has been described in this review. It is based on three techniques for eliminating ligands from the inner sphere of the original compounds: 1) binding of the ligands in sparingly soluble productions or their conversion into highly volatile compounds; 2) binding of the ligands in stronger compounds than the original products; 3) chemical conversion of coordinated ligands, which result in a loss of donor capacity by the reaction products and the departure of these products from the inner sphere of the complex compounds. If the solvent in which the reaction is carried out has a sufficient donor capability, the coordination capacity of the central ion is saturated by means of solvent molecules with the formation of a solvento complex. The method has been illustrated by a large number of concrete examples of reactions which result in the formation of compounds with an assigned composition.

  5. Convergence of Acquired Mutations and Alternative Splicing of CD19 Enables Resistance to CART-19 Immunotherapy

    Science.gov (United States)

    Sotillo, Elena; Barrett, David M.; Black, Kathryn L; Bagashev, Asen; Oldridge, Derek; Wu, Glendon; Sussman, Robyn; Lanauze, Claudia; Ruella, Marco; Gazzara, Matthew R.; Martinez, Nicole M.; Harrington, Colleen T.; Chung, Elaine Y.; Perazzelli, Jessica; Hofmann, Ted J.; Maude, Shannon L.; Raman, Pichai; Barrera, Alejandro; Gill, Saar; Lacey, Simon F.; Melenhorst, Jan J.; Allman, David; Jacoby, Elad; Fry, Terry; Mackall, Crystal; Barash, Yoseph; Lynch, Kristen W.; Maris, John M.; Grupp, Stephan A.; Thomas-Tikhonenko, Andrei

    2015-01-01

    The CD19 antigen, expressed on most B-cell acute lymphoblastic leukemias (B-ALL), can be targeted with chimeric antigen receptor–armed T cells (CART-19), but relapses with epitope loss occur in 10% to 20% of pediatric responders. We detected hemizygous deletions spanning the CD19 locus and de novo frameshift and missense mutations in exon 2 of CD19 in some relapse samples. However, we also discovered alternatively spliced CD19 mRNA species, including one lacking exon 2. Pull-down/siRNA experiments identified SRSF3 as a splicing factor involved in exon 2 retention, and its levels were lower in relapsed B-ALL. Using genome editing, we demonstrated that exon 2 skipping bypasses exon 2 mutations in B-ALL cells and allows expression of the N-terminally truncated CD19 variant, which fails to trigger killing by CART-19 but partly rescues defects associated with CD19 loss. Thus, this mechanism of resistance is based on a combination of deleterious mutations and ensuing selection for alternatively spliced RNA isoforms. Significance CART-19 yield 70% response rates in patients with B-ALL, but also produce escape variants. We discovered that the underlying mechanism is the selection for preexisting alternatively spliced CD19 isoforms with the compromised CART-19 epitope. This mechanism suggests a possibility of targeting alternative CD19 ectodomains, which could improve survival of patients with B-cell neoplasms. PMID:26516065

  6. Therapeutic targeting of CD19 in hematological malignancies: past, present, future and beyond.

    Science.gov (United States)

    Katz, Ben-Zion; Herishanu, Yair

    2014-05-01

    Abstract During the past few decades, CD19 has been at the center of various scientific/translational endeavors to develop targeted therapeutics against B-cell malignancies. Due to the expression pattern of CD19 throughout the B-cell lineage, and on most B-cell malignancies, it became a preferred target for the development of experimental therapeutic agents during the first years of the monoclonal antibodies era. Successful preclinical experiments led to the first generation of clinical trials, based predominantly on toxin/anti-CD19 murine immunoconjugates. These, however, mostly failed due to poor biochemical design of the reagents, and the generation of human anti-murine antibodies. Modern anti-CD19 reagents are based on humanized anti-CD19 antibodies designed to attract components of the immune system, predominantly T-cells, to eliminate CD19+ target cells. These include, for example, modified anti-CD19 antibodies, and bispecific anti-CD19/CD3 antibodies. One of the most attractive approaches to target malignant B-cells is based on the introduction of chimeric antigen receptors (CARs) into patient derived T-cells. CARs are composed of extracellular recognition sequences derived from anti-CD19 antibodies, and intracellular signaling components that can foster T-cell activation. The novel anti-B-cell therapeutics have shown promising clinical effects against various B-cell malignancies, including acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL) and non-Hodgkin lymphoma (NHL), although expected side effects (e.g. significant immunosuppression) were also recorded. These novel successful anti-CD19 agents may have the potential to be used in other fields, such as autoimmunity.

  7. Pattern Formation and Complexity Emergence

    Science.gov (United States)

    Berezin, Alexander A.

    2001-03-01

    Success of nonlinear modelling of pattern formation and self-organization encourages speculations on informational and number theoretical foundations of complexity emergence. Pythagorean "unreasonable effectiveness of integers" in natural processes is perhaps extrapolatable even to universal emergence "out-of-nothing" (Leibniz, Wheeler). Because rational numbers (R = M/N) are everywhere dense on real axis, any digital string (hence any "book" from "Library of Babel" of J.L.Borges) is "recorded" infinitely many times in arbitrary many rationals. Furthermore, within any arbitrary small interval there are infinitely many Rs for which (either or both) integers (Ms and Ns) "carry" any given string of any given length. Because any iterational process (such as generation of fractal features of Mandelbrot Set) is arbitrary closely approximatable with rational numbers, the infinite pattern of integers expresses itself in generation of complexity of the world, as well as in emergence of the world itself. This "tunnelling" from Platonic World ("Platonia" of J.Barbour) to a real (physical) world is modern recast of Leibniz's motto ("for deriving all from nothing there suffices a single principle").

  8. Stereoregularity Drives Precipitation in Polyelectrolyte Complex Formation

    Science.gov (United States)

    Tirrell, Matthew; Perry, Sarah; Leon, Lorraine; Kade, Matthew; Priftis, Dimitris; Black, Katie; Hoffman, Kyle; Whitmer, Jonathan; Qin, Jian; de Pablo, Juan

    2014-03-01

    This study investigates the effect of stereoregularity on the formation of polypeptide-based complex formation and assembly into micelles, hydrogels and ordered phases. We demonstrate that fluid complex coacervate formation (rather than solid complex precipitation) between oppositely charged polypeptides requires at least one racemic partner in order to disrupt backbone hydrogen bonding networks and prevent the hydrophobic collapse of the polymers into compact, fibrillar secondary structures. Computer simulations bear this out and enable visualization of the molecular structure of the complexes. The ability to choose between conditions of fluid phase formation and solid phase formation is a useful tool in developing new self-assembled materials based on polyelectrolyte complex formation. Support from the Argonne National Laboratory Laboratory Research and Development Program (2011-217) is gratefully acknowledged.

  9. A Tet-On Inducible System for Controlling CD19-Chimeric Antigen Receptor Expression upon Drug Administration.

    Science.gov (United States)

    Sakemura, Reona; Terakura, Seitaro; Watanabe, Keisuke; Julamanee, Jakrawadee; Takagi, Erina; Miyao, Kotaro; Koyama, Daisuke; Goto, Tatsunori; Hanajiri, Ryo; Nishida, Tetsuya; Murata, Makoto; Kiyoi, Hitoshi

    2016-08-01

    T cells genetically modified with a CD19 chimeric antigen receptor (CD19CAR) are remarkably effective against B-cell malignancies in clinical trials. However, major concerns remain regarding toxicities, such as hypogammaglobulinemia, due to B-cell aplasia or severe cytokine release syndrome after overactivation of CAR T cells. To resolve these adverse events, we aimed to develop an inducible CAR system by using a tetracycline regulation system that would be activated only in the presence of doxycycline (Dox). In this study, the second-generation CD19CAR was fused into the third-generation Tet-On vector (Tet-CD19CAR) and was retrovirally transduced into primary CD8(+) T cells. Tet-CD19CAR T cells were successfully generated and had minimal background CD19CAR expression without Dox. Tet-CD19CAR T cells in the presence of Dox were equivalently cytotoxic against CD19(+) cell lines and had equivalent cytokine production and proliferation upon CD19 stimulation, compared with conventional CD19CAR T cells. The Dox(+) Tet-CD19CAR T cells also had significant antitumor activity in a xenograft model. However, without Dox, Tet-CD19CAR T cells lost CAR expression and CAR T-cell functions in vitro and in vivo, clearly segregating the "On" and "Off" status of Tet-CD19CAR cells by Dox administration. In addition to suicide-gene technology, controlling the expression and the functions of CAR with an inducible vector is a potential solution for CAR T-cell therapy-related toxicities, and may improve the safety profile of CAR T-cell therapy. This strategy might also open the way to treat other malignancies in combination with other CAR or TCR gene-modified T cells. Cancer Immunol Res; 4(8); 658-68. ©2016 AACRSee related Spotlight by June, p. 643.

  10. Clinical immunotherapy of B-cell malignancy using CD19-targeted CAR T-cells.

    Science.gov (United States)

    Maher, John

    2014-02-01

    The CD19 molecule is ubiquitously expressed throughout all stages of B-cell differentiation, but is not found on haemopoietic stem cells. Since most B-cell leukaemias and lymphomas retain CD19 expression, it represents an excellent target for immunotherapy of these malignant disorders. Over the past 10 years, compelling pre-clinical evidence has accrued to indicate that expression of a CD19-targeted chimeric antigen receptor (CAR) in peripheral blood T-cells exerts therapeutic efficacy in diverse models of B-cell malignancy. Building on this, clinical studies are ongoing in several centres in which autologous CD19-specific CAR T-cells are undergoing evaluation in patients with acute and chronic B-cell leukaemia and refractory lymphoma. Early data have generated considerable excitement, providing grounds to speculate that CAR-based immunotherapy will radically alter existing management paradigms in B-cell malignancy. The focus of this mini-review is to evaluate these emerging clinical data and to speculate on clinical prospects for this new therapeutic modality.

  11. CD19-CAR engineered NK-92 cells are sufficient to overcome NK cell resistance in B-cell malignancies.

    Science.gov (United States)

    Romanski, Annette; Uherek, Christoph; Bug, Gesine; Seifried, Erhard; Klingemann, Hans; Wels, Winfried S; Ottmann, Oliver G; Tonn, Torsten

    2016-07-01

    Many B-cell acute and chronic leukaemias tend to be resistant to killing by natural killer (NK) cells. The introduction of chimeric antigen receptors (CAR) into T cells or NK cells could potentially overcome this resistance. Here, we extend our previous observations on the resistance of malignant lymphoblasts to NK-92 cells, a continuously growing NK cell line, showing that anti-CD19-CAR (αCD19-CAR) engineered NK-92 cells can regain significant cytotoxicity against CD19 positive leukaemic cell lines and primary leukaemia cells that are resistant to cytolytic activity of parental NK-92 cells. The 'first generation' CAR was generated from a scFv (CD19) antibody fragment, coupled to a flexible hinge region, the CD3ζ chain and a Myc-tag and cloned into a retrovirus backbone. No difference in cytotoxic activity of NK-92 and transduced αCD19-CAR NK-92 cells towards CD19 negative targets was found. However, αCD19-CAR NK-92 cells specifically and efficiently lysed CD19 expressing B-precursor leukaemia cell lines as well as lymphoblasts from leukaemia patients. Since NK-92 cells can be easily expanded to clinical grade numbers under current Good Manufactoring Practice (cGMP) conditions and its safety has been documented in several phase I clinical studies, treatment with CAR modified NK-92 should be considered a treatment option for patients with lymphoid malignancies.

  12. STAR FORMATION ACROSS THE W3 COMPLEX

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    Román-Zúñiga, Carlos G.; Ybarra, Jason E.; Tapia, Mauricio [Instituto de Astronomía, Universidad Nacional Autónoma de México, Unidad Académica en Ensenada, Km 103 Carr. Tijuana–Ensenada, Ensenada 22860 (Mexico); Megías, Guillermo D. [Facultad de Física. Universidad de Sevilla. Dpto. Física Atómica, Molecular y Nuclear, Sevilla, E-41080 (Spain); Lada, Elizabeth A. [Astronomy Department, University of Florida, 211 Bryant Space Sciences Center, FL 32611 (United States); Alves, Joáo F. [Institute of Astronomy, University of Vienna, Türkenschanzstr. 17, A-1180 Vienna (Austria)

    2015-09-15

    We present a multi-wavelength analysis of the history of star formation in the W3 complex. Using deep, near-infrared ground-based images combined with images obtained with Spitzer and Chandra observatories, we identified and classified young embedded sources. We identified the principal clusters in the complex and determined their structure and extension. We constructed extinction-limited samples for five principal clusters and constructed K-band luminosity functions that we compare with those of artificial clusters with varying ages. This analysis provided mean ages and possible age spreads for the clusters. We found that IC 1795, the centermost cluster of the complex, still hosts a large fraction of young sources with circumstellar disks. This indicates that star formation was active in IC 1795 as recently as 2 Myr ago, simultaneous to the star-forming activity in the flanking embedded clusters, W3-Main and W3(OH). A comparison with carbon monoxide emission maps indicates strong velocity gradients in the gas clumps hosting W3-Main and W3(OH) and shows small receding clumps of gas at IC 1795, suggestive of rapid gas removal (faster than the T Tauri timescale) in the cluster-forming regions. We discuss one possible scenario for the progression of cluster formation in the W3 complex. We propose that early processes of gas collapse in the main structure of the complex could have defined the progression of cluster formation across the complex with relatively small age differences from one group to another. However, triggering effects could act as catalysts for enhanced efficiency of formation at a local level, in agreement with previous studies.

  13. Star Formation Across the W3 Complex

    CERN Document Server

    Román-Zúñiga, C G; Megias, G; Tapia, M; Lada, E A; Alves, J F

    2015-01-01

    We present a multi-wavelength analysis of the history of star formation in the W3 complex. Using deep, near-infrared ground-based images, combined with images obtained with Spitzer and Chandra observatories, we identified and classified young embedded sources. We identified the principal clusters in the complex, and determined their structure and extension. We constructed extinction-limited samples for five principal clusters, and constructed K-band luminosity functions (KLF) that we compare with those of artificial clusters with varying ages. This analysis provided mean ages and possible age spreads for the clusters. We found that IC 1795, the centermost cluster of the complex, still hosts a large fraction of young sources with circumstellar disks. This indicates that star formation was active in IC 1795 as recently as 2 Myr ago, simultaneous to the star forming activity in the flanking embedded clusters, W3-Main and W3(OH). A comparison with carbon monoxide emission maps indicates strong velocity gradients ...

  14. Interactive formation control in complex environments.

    Science.gov (United States)

    Henry, Joseph; Shum, Hubert P H; Komura, Taku

    2014-02-01

    The degrees of freedom of a crowd is much higher than that provided by a standard user input device. Typically, crowd-control systems require multiple passes to design crowd movements by specifying waypoints, and then defining character trajectories and crowd formation. Such multi-pass control would spoil the responsiveness and excitement of real-time control systems. In this paper, we propose a single-pass algorithm to control a crowd in complex environments. We observe that low-level details in crowd movement are related to interactions between characters and the environment, such as diverging/merging at cross points, or climbing over obstacles. Therefore, we simplify the problem by representing the crowd with a deformable mesh, and allow the user, via multitouch input, to specify high-level movements and formations that are important for context delivery. To help prevent congestion, our system dynamically reassigns characters in the formation by employing a mass transport solver to minimize their overall movement. The solver uses a cost function to evaluate the impact from the environment, including obstacles and areas affecting movement speed. Experimental results show realistic crowd movement created with minimal high-level user inputs. Our algorithm is particularly useful for real-time applications including strategy games and interactive animation creation.

  15. CD19 CAR immune pressure induces B-precursor acute lymphoblastic leukaemia lineage switch exposing inherent leukaemic plasticity.

    Science.gov (United States)

    Jacoby, Elad; Nguyen, Sang M; Fountaine, Thomas J; Welp, Kathryn; Gryder, Berkley; Qin, Haiying; Yang, Yinmeng; Chien, Christopher D; Seif, Alix E; Lei, Haiyan; Song, Young K; Khan, Javed; Lee, Daniel W; Mackall, Crystal L; Gardner, Rebecca A; Jensen, Michael C; Shern, Jack F; Fry, Terry J

    2016-07-27

    Adoptive immunotherapy using chimeric antigen receptor (CAR) expressing T cells targeting the CD19 B lineage receptor has demonstrated marked success in relapsed pre-B-cell acute lymphoblastic leukaemia (ALL). Persisting CAR-T cells generate sustained pressure against CD19 that may drive unique mechanisms of resistance. Pre-B ALL originates from a committed pre-B cell or an earlier progenitor, with potential to reprogram into other hematopoietic lineages. Here we report changes in lineage markers including myeloid conversion in patients following CD19 CAR therapy. Using murine ALL models we study the long-term effects of CD19 CAR-T cells and demonstrate partial or complete lineage switch as a consistent mechanism of CAR resistance depending on the underlying genetic oncogenic driver. Deletion of Pax5 or Ebf1 recapitulates lineage reprogramming occurring during CD19 CAR pressure. Our findings establish lineage switch as a mechanism of CAR resistance exposing inherent plasticity in genetic subtypes of pre-B-cell ALL.

  16. Widespread cotranslational formation of protein complexes.

    Directory of Open Access Journals (Sweden)

    Caia D S Duncan

    2011-12-01

    Full Text Available Most cellular processes are conducted by multi-protein complexes. However, little is known about how these complexes are assembled. In particular, it is not known if they are formed while one or more members of the complexes are being translated (cotranslational assembly. We took a genomic approach to address this question, by systematically identifying mRNAs associated with specific proteins. In a sample of 31 proteins from Schizosaccharomyces pombe that did not contain RNA-binding domains, we found that ∼38% copurify with mRNAs that encode interacting proteins. For example, the cyclin-dependent kinase Cdc2p associates with the rum1 and cdc18 mRNAs, which encode, respectively, an inhibitor of Cdc2p kinase activity and an essential regulator of DNA replication. Both proteins interact with Cdc2p and are key cell cycle regulators. We obtained analogous results with proteins with different structures and cellular functions (kinesins, protein kinases, transcription factors, proteasome components, etc.. We showed that copurification of a bait protein and of specific mRNAs was dependent on the presence of the proteins encoded by the interacting mRNAs and on polysomal integrity. These results indicate that these observed associations reflect the cotranslational interaction between the bait and the nascent proteins encoded by the interacting mRNAs. Therefore, we show that the cotranslational formation of protein-protein interactions is a widespread phenomenon.

  17. [CD4+, CD8+ AND CD19+ cells in individuals with dyslipidemia].

    Science.gov (United States)

    Pereira de Moura, Jose; Santos Rosa, Manuel; Alves, Vera; Mota Pinto, Anabela; Rodrigues, Victor; Silva, José Manuel; Alves de Moura, J J

    2013-01-01

    Introdução: Os mecanismos imunológicos e inflamatórios têm um papel crucial no desenvolvimento da aterosclerose e na sua tradução clínica. São inúmeros os estudos que procuraram relacionar os mais diversos marcadores inflamatórios – leucócitos, proteína C reactiva, interleucinas, quimiocinas, moléculas de adesão, metaloproteinases, etc – com os factores de risco clássicos da aterosclerose, a formação da placa e os fenómenos clínicos. Não são tantos, que tenhamos conhecimento, os trabalhos que analisaram o comportamento das diversas células mononucleares na fisiopatologia da aterosclerose. Sendo os monócitos/macrófagos e os linfócitos células fundamentais no desencadear e posterior evolução desta doença vascular, procurámos determinar as percentagens das diversas populações celulares periféricas em indivíduos dislipidémicos e em normolipidémicos.Material e Métodos: Por citometria de fluxo, determinámos em indivíduos com dislipidemia e num grupo controlo, as concentrações no sangue periférico dos CD3+, CD4+, CD8+, CD19+, CD56+, CD56CD8+, DN, CD25+, CD26+, CD25CD3+, CD26CD3+, CD25CD26CD3+, CCR5+, CCR5CD3+, CCR5CD4+, HLADR+, HLADRCD4+, HLADRCD8h+, HLADRCD8low+, HLADRCD8+, CD95+, CD95CD95L+, CD3CD95+, CD3CD95L+, CD62L+, CD3CD62L+, CD69+, CD69CD3+ e CD69CD4+. Resultados: Embora na sua grande maioria não tenham sido encontradas diferenças significativas entre os dois grupos de participantes, verificaram-se em algumas populações celulares, resultados que nos mereceram alguns comentários. Neste artigo debruçámo-nos apenas sobre as populações positivas para os CD4, CD8 e CD19.Discussão: A menor concentração das células CD4+ na nossa população de dislipidémicos foi aparentemente inesperada devido ao relacionamento existente entre este tipo celular, os factores de risco e a aterosclerose. Não foram determinados os subtipos Th1 e Th2, nem a população de células reguladoras CD4+CD25+, que poderiam explicar a

  18. PTEN and PI-3 kinase inhibitors control LPS signaling and the lymphoproliferative response in the CD19+ B cell compartment

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Alok R. [UCSD Department of Pediatrics, Moores UCSD Cancer Center, University of California School of Medicine, San Diego, CA 92093 (United States); Peirce, Susan K. [Department of Pediatrics, Emory University School of Medicine, Atlanta, GA (United States); Joshi, Shweta [UCSD Department of Pediatrics, Moores UCSD Cancer Center, University of California School of Medicine, San Diego, CA 92093 (United States); Durden, Donald L., E-mail: ddurden@ucsd.edu [UCSD Department of Pediatrics, Moores UCSD Cancer Center, University of California School of Medicine, San Diego, CA 92093 (United States); Division of Pediatric Hematology-Oncology, UCSD Rady Children' s Hospital, La Jolla, CA (United States)

    2014-09-10

    Pattern recognition receptors (PRRs), e.g. toll receptors (TLRs) that bind ligands within the microbiome have been implicated in the pathogenesis of cancer. LPS is a ligand for two TLR family members, TLR4 and RP105 which mediate LPS signaling in B cell proliferation and migration. Although LPS/TLR/RP105 signaling is well-studied; our understanding of the underlying molecular mechanisms controlling these PRR signaling pathways remains incomplete. Previous studies have demonstrated a role for PTEN/PI-3K signaling in B cell selection and survival, however a role for PTEN/PI-3K in TLR4/RP105/LPS signaling in the B cell compartment has not been reported. Herein, we crossed a CD19cre and PTEN{sup fl/fl} mouse to generate a conditional PTEN knockout mouse in the CD19+ B cell compartment. These mice were further crossed with an IL-14α transgenic mouse to study the combined effect of PTEN deletion, PI-3K inhibition and expression of IL-14α (a cytokine originally identified as a B cell growth factor) in CD19+ B cell lymphoproliferation and response to LPS stimulation. Targeted deletion of PTEN and directed expression of IL-14α in the CD19+ B cell compartment (IL-14+PTEN-/-) lead to marked splenomegaly and altered spleen morphology at baseline due to expansion of marginal zone B cells, a phenotype that was exaggerated by treatment with the B cell mitogen and TLR4/RP105 ligand, LPS. Moreover, LPS stimulation of CD19+ cells isolated from these mice display increased proliferation, augmented AKT and NFκB activation as well as increased expression of c-myc and cyclinD1. Interestingly, treatment of LPS treated IL-14+PTEN-/- mice with a pan PI-3K inhibitor, SF1126, reduced splenomegaly, cell proliferation, c-myc and cyclin D1 expression in the CD19+ B cell compartment and normalized the splenic histopathologic architecture. These findings provide the direct evidence that PTEN and PI-3K inhibitors control TLR4/RP105/LPS signaling in the CD19+ B cell compartment and that pan PI

  19. The Tol2 transposon system mediates the genetic engineering of T-cells with CD19-specific chimeric antigen receptors for B-cell malignancies.

    Science.gov (United States)

    Tsukahara, T; Iwase, N; Kawakami, K; Iwasaki, M; Yamamoto, C; Ohmine, K; Uchibori, R; Teruya, T; Ido, H; Saga, Y; Urabe, M; Mizukami, H; Kume, A; Nakamura, M; Brentjens, R; Ozawa, K

    2015-02-01

    Engineered T-cell therapy using a CD19-specific chimeric antigen receptor (CD19-CAR) is a promising strategy for the treatment of advanced B-cell malignancies. Gene transfer of CARs to T-cells has widely relied on retroviral vectors, but transposon-based gene transfer has recently emerged as a suitable nonviral method to mediate stable transgene expression. The advantages of transposon vectors compared with viral vectors include their simplicity and cost-effectiveness. We used the Tol2 transposon system to stably transfer CD19-CAR into human T-cells. Normal human peripheral blood lymphocytes were co-nucleofected with the Tol2 transposon donor plasmid carrying CD19-CAR and the transposase expression plasmid and were selectively propagated on NIH3T3 cells expressing human CD19. Expanded CD3(+) T-cells with stable and high-level transgene expression (~95%) produced interferon-γ upon stimulation with CD19 and specifically lysed Raji cells, a CD19(+) human B-cell lymphoma cell line. Adoptive transfer of these T-cells suppressed tumor progression in Raji tumor-bearing Rag2(-/-)γc(-/-) immunodeficient mice compared with control mice. These results demonstrate that the Tol2 transposon system could be used to express CD19-CAR in genetically engineered T-cells for the treatment of refractory B-cell malignancies.

  20. Wiskott-Aldrich Syndrome Interacting Protein Deficiency Uncovers the Role of the Co-receptor CD19 as a Generic Hub for PI3 Kinase Signaling in B Cells.

    Science.gov (United States)

    Keppler, Selina Jessica; Gasparrini, Francesca; Burbage, Marianne; Aggarwal, Shweta; Frederico, Bruno; Geha, Raif S; Way, Michael; Bruckbauer, Andreas; Batista, Facundo D

    2015-10-20

    Humans with Wiskott-Aldrich syndrome display a progressive immunological disorder associated with compromised Wiskott-Aldrich Syndrome Interacting Protein (WIP) function. Mice deficient in WIP recapitulate such an immunodeficiency that has been attributed to T cell dysfunction; however, any contribution of B cells is as yet undefined. Here we have shown that WIP deficiency resulted in defects in B cell homing, chemotaxis, survival, and differentiation, ultimately leading to diminished germinal center formation and antibody production. Furthermore, in the absence of WIP, several receptors, namely the BCR, BAFFR, CXCR4, CXCR5, CD40, and TLR4, were impaired in promoting CD19 co-receptor activation and subsequent PI3 kinase (PI3K) signaling. The underlying mechanism was due to a distortion in the actin and tetraspanin networks that lead to altered CD19 cell surface dynamics. In conclusion, our findings suggest that, by regulating the cortical actin cytoskeleton, WIP influences the function of CD19 as a general hub for PI3K signaling.

  1. CD19-Targeted chimeric antigen receptor-modified T-cell immunotherapy for B-cell malignancies.

    Science.gov (United States)

    Turtle, C J; Riddell, S R; Maloney, D G

    2016-09-01

    Chimeric antigen receptors (CARs) comprise a tumor-targeting moiety, often in the form of a single chain variable fragment derived from a monoclonal antibody, fused to one or more intracellular T-cell signaling sequences. Lymphodepletion chemotherapy followed by infusion of T cells that are genetically modified to express a CD19-specific CAR is a promising therapy for patients with refractory CD19(+) B-cell malignancies, producing rates of complete remission that are remarkably high in acute lymphoblastic leukemia and encouraging in non-Hodgkin lymphoma and chronic lymphocytic leukemia. Responses are often durable, although additional studies are needed to define the role of CAR-T cell immunotherapy in the context of other treatments. CAR-modified T-cell immunotherapy can be complicated by cytokine release syndrome and neurologic toxicity, which in most cases are manageable and reversible. Here we review recent clinical trial data and discuss issues for the field.

  2. Dynamics of lane formation in driven binary complex plasmas

    NARCIS (Netherlands)

    Sutterlin, K. R.; Wysocki, A.; Ivlev, A. V.; Rath, C.; Thomas, H. M.; Rubin-Zuzic, M.; W. J. Goedheer,; Fortov, V. E.; Lipaev, A. M.; Molotkov, V. I.; Petrov, O. F.; Morfill, G. E.; Lowen, H.

    2009-01-01

    The dynamical onset of lane formation is studied in experiments with binary complex plasmas under microgravity conditions. Small microparticles are driven and penetrate into a cloud of big particles, revealing a strong tendency towards lane formation. The observed time-resolved lane-formation proces

  3. CD19-Chimeric Antigen Receptor T Cells for Treatment of Chronic Lymphocytic Leukaemia and Acute Lymphoblastic Leukaemia

    DEFF Research Database (Denmark)

    Lorentzen, C L; thor Straten, Per

    2015-01-01

    Adoptive cell therapy (ACT) for cancer represents a promising new treatment modality. ACT based on the administration of cytotoxic T cells genetically engineered to express a chimeric antigen receptor (CAR) recognizing CD19 expressed by B cell malignancies has been shown to induce complete lasting......-associated toxicities, which needs attention. Herein we review current data and discuss key aspects of this powerful approach to treat and potentially cure B cell malignancies....

  4. Anti-CD19 chimeric antigen receptor T-cell therapy for adult Philadelphia chromosome-positive acute lymphoblastic leukemia

    Science.gov (United States)

    Zhu, Yang-min; Wu, Zhao; Tan, You-ping; Du, Yuan-yuan; Liu, Zhi; Ou, Rui-ming; Liu, Shuang; Pu, Cheng-fei; Jiang, Jing; Wang, Jin-ping; Xiao, Lei; Zhang, Qing

    2016-01-01

    Abstract Rationale: The presence of the Philadelphia chromosome (Ph) in acute lymphoblastic leukemia (ALL) has been associated with a high risk of disease relapse and a poor prognosis. Allogeneic hematopoietic stem cell transplantation (HSCT) is an established treatment for adults with Ph-positive ALL, but relapse remains the primary cause of treatment failure, and is associated with an extremely poor prognosis. The emergence of resistance to tyrosine kinase inhibitors (TKIs) poses a challenge for patients with disease relapses after initial treatment with TKI-containing regimens. Patient concerns: Two patients with TKI-resistant recurrent Ph-positive ALL. Diagnoses: Ph-positive ALL. Interventions: Anti-CD19 CAR T-cell infusion. Outcomes: One patient's bone marrow blasts decreased significantly, and the other reached negative minimal residual disease (MRD). However, we first recorded the development of new-onset acute graft-versus-host disease (aGVHD) after anti-CD19 CAR T-cell infusion in a patient who received allogeneic HSCT. Our 2 case reports also demonstrate the efficacy of anti-CD19 CAR T-cell therapy in the treatment of TKI-resistant Ph-positive ALL. Lessons: Our report suggests that anti-CD19 CAR T-cell therapy may be a promising option for the treatment of relapsed Ph-positive ALL after conventional chemotherapy or allogeneic HSCT. However, caution is due given the possibility of the adverse effects of cytokine release syndrome (CRS)-induced aGVHD for patients receiving allogeneic HSCT. PMID:28002337

  5. Phase 1 studies of central memory-derived CD19 CAR T-cell therapy following autologous HSCT in patients with B-cell NHL.

    Science.gov (United States)

    Wang, Xiuli; Popplewell, Leslie L; Wagner, Jamie R; Naranjo, Araceli; Blanchard, M Suzette; Mott, Michelle R; Norris, Adam P; Wong, ChingLam W; Urak, Ryan Z; Chang, Wen-Chung; Khaled, Samer K; Siddiqi, Tanya; Budde, Lihua E; Xu, Jingying; Chang, Brenda; Gidwaney, Nikita; Thomas, Sandra H; Cooper, Laurence J N; Riddell, Stanley R; Brown, Christine E; Jensen, Michael C; Forman, Stephen J

    2016-06-16

    Myeloablative autologous hematopoietic stem cell transplantation (HSCT) is a mainstay of therapy for relapsed intermediate-grade B-cell non-Hodgkin lymphoma (NHL); however, relapse rates are high. In phase 1 studies designed to improve long-term remission rates, we administered adoptive T-cell immunotherapy after HSCT, using ex vivo-expanded autologous central memory-enriched T cells (TCM) transduced with lentivirus expressing CD19-specific chimeric antigen receptors (CARs). We present results from 2 safety/feasibility studies, NHL1 and NHL2, investigating different T-cell populations and CAR constructs. Engineered TCM-derived CD19 CAR T cells were infused 2 days after HSCT at doses of 25 to 200 × 10(6) in a single infusion. In NHL1, 8 patients safely received T-cell products engineered from enriched CD8(+) TCM subsets, expressing a first-generation CD19 CAR containing only the CD3ζ endodomain (CD19R:ζ). Four of 8 patients (50%; 95% confidence interval [CI]: 16-84%) were progression free at both 1 and 2 years. In NHL2, 8 patients safely received T-cell products engineered from enriched CD4(+) and CD8(+) TCM subsets and expressing a second-generation CD19 CAR containing the CD28 and CD3ζ endodomains (CD19R:28ζ). Six of 8 patients (75%; 95% CI: 35-97%) were progression free at 1 year. The CD4(+)/CD8(+) TCM-derived CD19 CAR T cells (NHL2) exhibited improvement in expansion; however, persistence was ≤28 days, similar to that seen by others using CD28 CARs. Neither cytokine release syndrome nor delayed hematopoietic engraftment was observed in either trial. These data demonstrate the safety and feasibility of CD19 CAR TCM therapy after HSCT. Trials were registered at www.clinicaltrials.gov as #NCT01318317 and #NCT01815749.

  6. The synaptic recruitment of lipid rafts is dependent on CD19-PI3K module and cytoskeleton remodeling molecules.

    Science.gov (United States)

    Xu, Liling; Auzins, Arturs; Sun, Xiaolin; Xu, Yinsheng; Harnischfeger, Fiona; Lu, Yun; Li, Zhanguo; Chen, Ying-Hua; Zheng, Wenjie; Liu, Wanli

    2015-08-01

    Sphingolipid- and cholesterol-rich lipid raft microdomains are important in the initiation of BCR signaling. Although it is known that lipid rafts promote the coclustering of BCR and Lyn kinase microclusters within the B cell IS, the molecular mechanism of the recruitment of lipid rafts into the B cell IS is not understood completely. Here, we report that the synaptic recruitment of lipid rafts is dependent on the cytoskeleton-remodeling proteins, RhoA and Vav. Such an event is also efficiently regulated by motor proteins, myosin IIA and dynein. Further evidence suggests the synaptic recruitment of lipid rafts is, by principle, an event triggered by BCR signaling molecules and second messenger molecules. BCR-activating coreceptor CD19 potently enhances such an event depending on its cytoplasmic Tyr421 and Tyr482 residues. The enhancing function of the CD19-PI3K module in synaptic recruitment of lipid rafts is also confirmed in human peripheral blood B cells. Thus, these results improve our understanding of the molecular mechanism of the recruitment of lipid raft microdomains in B cell IS.

  7. Case Report: CD19-positive acute myeloblastic leukemia with trisomy 21 as a sole acquired karyotypic abnormality

    Institute of Scientific and Technical Information of China (English)

    Hua-feng WANG; Yi-zhi CHENG; Huan-ping WANG; Zhi-mei CHEN; Ji-yu LOU; Jie JIN

    2009-01-01

    We report that a 63-year-old Chinese female had acute myeloblastic leukemia (AML) in which trisomy 21 (+21) was found as the sole acquired karyotypic abnormality. The blasts were positive for myeloperoxidase, and the immunophenotype was positive for cluster of differentiation 19 (CDI9), CD33, CD34, and human leukocyte antigens (HLA)-DR. The chromosomal analysis of bone marrow showed 47,XX,+21 [2]/46,XX[18]. Fluorescent in situ hybridization (FISH) showed that three copies of AML1 were situated in separate chromosomes, and that t(8;21) was negative. The patient did not have any features of Down syndrome. A diagnosis of CD19-positive AML-M5 was established with trisomy 21 as a sole acquired karyotypic abnormality. The patient did not respond well to chemotherapy and died three months after the diagnosis. This is the first reported case of CD19-positive AM L with trisomy 21 as the sole cytogenetic abnormality. The possible prognostic significance of the finding in AML with +21 as the sole acquired karyotypic abnormality was discussed.

  8. Curcumin complexation with cyclodextrins by the autoclave process: Method development and characterization of complex formation.

    Science.gov (United States)

    Hagbani, Turki Al; Nazzal, Sami

    2017-03-30

    One approach to enhance curcumin (CUR) aqueous solubility is to use cyclodextrins (CDs) to form inclusion complexes where CUR is encapsulated as a guest molecule within the internal cavity of the water-soluble CD. Several methods have been reported for the complexation of CUR with CDs. Limited information, however, is available on the use of the autoclave process (AU) in complex formation. The aims of this work were therefore to (1) investigate and evaluate the AU cycle as a complex formation method to enhance CUR solubility; (2) compare the efficacy of the AU process with the freeze-drying (FD) and evaporation (EV) processes in complex formation; and (3) confirm CUR stability by characterizing CUR:CD complexes by NMR, Raman spectroscopy, DSC, and XRD. Significant differences were found in the saturation solubility of CUR from its complexes with CD when prepared by the three complexation methods. The AU yielded a complex with expected chemical and physical fingerprints for a CUR:CD inclusion complex that maintained the chemical integrity and stability of CUR and provided the highest solubility of CUR in water. Physical and chemical characterizations of the AU complexes confirmed the encapsulated of CUR inside the CD cavity and the transformation of the crystalline CUR:CD inclusion complex to an amorphous form. It was concluded that the autoclave process with its short processing time could be used as an alternate and efficient methods for drug:CD complexation.

  9. Liesegang patterns: Complex formation of precipitate in an electric field

    Indian Academy of Sciences (India)

    István Lagzi

    2005-02-01

    Formation of 1D Liesegang patterns was studied numerically in precipitation and reversible complex formation of precipitate scenarios in an electric field. The Ostwald’s supersaturation model reported by Büki, Kárpáti-Smidróczki and Zrínyi (BKZ model) was extended further. In the presence of an electric field the position of the first and the last bands () measured from the junction point of the outer and the inner electrolytes can be described by the function = 1 $_{}^{1/2}$ + 2 + 3 , where is the time elapsed until the nth band formation, 1, 2 and 3 are constants. The variation of the total number of bands with different electric field strengths () has a maximum. For higher one can observe a moving precipitation zone that becomes wider due to precipitation and reversible complex formation.

  10. Geology of the Biwabik Iron Formation and Duluth Complex.

    Science.gov (United States)

    Jirsa, Mark A; Miller, James D; Morey, G B

    2008-10-01

    The Biwabik Iron Formation is a approximately 1.9 billion year-old sequence of iron-rich sedimentary rocks that was metamorphosed at its eastern-most extent by approximately 1.1 billion year-old intrusions of the Duluth Complex. The metamorphic recrystallization of iron-formation locally produced iron-rich amphiboles and other fibrous iron-silicate minerals. The presence of these minerals in iron-formation along the eastern part of what is known as the Mesabi Iron Range, and their potential liberation by iron mining has raised environmental health concerns. We describe here the geologic setting and mineralogic composition of the Biwabik Iron Formation in and adjacent to the contact metamorphic aureole of the Duluth Complex. The effects of metamorphism are most pronounced within a few kilometers of the contact, and decrease progressively away from it. The contact aureole has been divided into four metamorphic zones-each characterized by the composition and crystal structure of the metamorphic minerals it contains. The recrystallization of iron-formation to iron-rich amphibole minerals (grunerite and cummingtonite) and iron-pyroxene minerals (hedenbergite and ferrohypersthene) is best developed in zones that are most proximal to the Duluth Complex contact.

  11. Pattern formation in oscillatory complex networks consisting of excitable nodes

    Science.gov (United States)

    Liao, Xuhong; Xia, Qinzhi; Qian, Yu; Zhang, Lisheng; Hu, Gang; Mi, Yuanyuan

    2011-05-01

    Oscillatory dynamics of complex networks has recently attracted great attention. In this paper we study pattern formation in oscillatory complex networks consisting of excitable nodes. We find that there exist a few center nodes and small skeletons for most oscillations. Complicated and seemingly random oscillatory patterns can be viewed as well-organized target waves propagating from center nodes along the shortest paths, and the shortest loops passing through both the center nodes and their driver nodes play the role of oscillation sources. Analyzing simple skeletons we are able to understand and predict various essential properties of the oscillations and effectively modulate the oscillations. These methods and results will give insights into pattern formation in complex networks and provide suggestive ideas for studying and controlling oscillations in neural networks.

  12. Inebilizumab, a B Cell-Depleting Anti-CD19 Antibody for the Treatment of Autoimmune Neurological Diseases: Insights from Preclinical Studies

    Directory of Open Access Journals (Sweden)

    Ding Chen

    2016-11-01

    Full Text Available Exaggerated or inappropriate responses by B cells are an important feature in many types of autoimmune neurological diseases. The recent success of B-cell depletion in the treatment of multiple sclerosis (MS has stimulated the development of novel B-cell-targeting therapies with the potential for improved efficacy. CD19 has emerged as a promising target for the depletion of B cells as well as CD19-positive plasmablasts and plasma cells. Inebilizumab (MEDI-551, an anti-CD19 antibody with enhanced antibody-dependent cell-mediated cytotoxicity against B cells, is currently being evaluated in MS and neuromyelitis optica. This review discusses the role of B cells in autoimmune neurological disorders, summarizes the development of inebilizumab, and analyzes the recent results for inebilizumab treatment in an autoimmune encephalitis mouse model. The novel insights obtained from these preclinical studies can potentially guide future investigation of inebilizumab in patients.

  13. Formation of Complex Molecules via radiative association reactions

    Science.gov (United States)

    Acharyya, Kinsuk; Herbst, Eric

    2016-07-01

    The detection of increasing numbers of complex organic molecules in the various phases of star formation plays a key role since they follow the same chemical rules of carbon-based chemistry that are observed in our planet Earth. Many of these molecules are believed to be formed on the surfaces of grains, and can then be released to the gas phase when these grains are heated. This is evident when we observe a rich chemistry in hot core regions. However, recently complex organic molecules have also been observed in cold clouds. Therefore, it is necessary to re-examine various pathways for the formation of these molecules in the gas phase. In this presentation, I will discuss role of radiative association reactions in the formation of complex molecules in the gas phase and at low temperature. We will compare abundance of assorted molecules with and without new radiative association reactions and will show that the abundance of a few complex molecules such as HCOOCH3, CH3OCH3 etc. can go up due to introduction of these reactions, which can help to explain their observed abundances.

  14. Gel phase formation in dilute triblock copolyelectrolyte complexes

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Samanvaya; Andreev, Marat; Levi, Adam E.; Goldfeld, David J.; Mao, Jun; Heller, William T.; Prabhu, Vivek M.; de Pablo, Juan J.; Tirrell, Matthew V.

    2017-02-23

    Assembly of oppositely charged triblock copolyelectrolytes into phase-separated gels at low polymer concentrations (<1% by mass) has been observed in scattering experiments and molecular dynamics simulations. Here we show that in contrast to uncharged, amphiphilic block copolymers that form discrete micelles at low concentrations and enter a phase of strongly interacting micelles in a gradual manner with increasing concentration, the formation of a dilute phase of individual micelles is prevented in polyelectrolyte complexation-driven assembly of triblock copolyelectrolytes. Gel phases form and phase separate almost instantaneously on solvation of the copolymers. Furthermore, molecular models of self-assembly demonstrate the presence of oligo-chain aggregates in early stages of copolyelectrolyte assembly, at experimentally unobservable polymer concentrations. Our discoveries contribute to the fundamental understanding of the structure and pathways of complexation-driven assemblies, and raise intriguing prospects for gel formation at extraordinarily low concentrations, with applications in tissue engineering, agriculture, water purification and theranostics.

  15. SPECTROPHOTOMETRIC STUDIES OF SANGUINARINE-Β-CYCLODEXTRIN COMPLEX FORMATION

    Directory of Open Access Journals (Sweden)

    Veaceslav Boldescu

    2008-06-01

    Full Text Available The main aim of this study was to investigate the influence of pH and the presence of hydrophilic polymer polyvinylpyrrolidone on the formation of sanguinarine-β-cyclodextrin (SANG-β-CD inclusion complex. Spectrophotometric studies of the SANG-β-CD systems in the presence and without 0.1 % PVP at the pH 5.0 did not show any evidence of the complex formation. However, the same systems showed several obvious evidences at the pH 8.0: the hyperchromic and the hypochromic effects and the presence of the isosbestic point in the region of 200 – 210 nm. The association constants calculated by three linear methods: Benesi-Hildebrand, Scott and Scatchard, were two times higher for the systems with addition of 0.1% PVP than for the systems without it.

  16. Formation of complex and unstable chromosomal translocations in yeast.

    Directory of Open Access Journals (Sweden)

    Kristina H Schmidt

    Full Text Available Genome instability, associated with chromosome breakage syndromes and most human cancers, is still poorly understood. In the yeast Saccharomyces cerevisiae, numerous genes with roles in the preservation of genome integrity have been identified. DNA-damage-checkpoint-deficient yeast cells that lack Sgs1, a RecQ-like DNA helicase related to the human Bloom's-syndrome-associated helicase BLM, show an increased rate of genome instability, and we have previously shown that they accumulate recurring chromosomal translocations between three similar genes, CAN1, LYP1 and ALP1. Here, the chromosomal location, copy number and sequence similarity of the translocation targets ALP1 and LYP1 were altered to gain insight into the formation of complex translocations. Among 844 clones with chromosomal rearrangements, 93 with various types of simple and complex translocations involving CAN1, LYP1 and ALP1 were identified. Breakpoint sequencing and mapping showed that the formation of complex translocation types is strictly dependent on the location of the initiating DNA break and revealed that complex translocations arise via a combination of interchromosomal translocation and template-switching, as well as from unstable dicentric intermediates. Template-switching occurred between sequences on the same chromosome, but was inhibited if the genes were transferred to different chromosomes. Unstable dicentric translocations continuously gave rise to clones with multiple translocations in various combinations, reminiscent of intratumor heterogeneity in human cancers. Base substitutions and evidence of DNA slippage near rearrangement breakpoints revealed that translocation formation can be accompanied by point mutations, and their presence in different translocation types within the same clone provides evidence that some of the different translocation types are derived from each other rather than being formed de novo. These findings provide insight into eukaryotic

  17. The Dynamics of Coalition Formation on Complex Networks

    Science.gov (United States)

    Auer, S.; Heitzig, J.; Kornek, U.; Schöll, E.; Kurths, J.

    2015-08-01

    Complex networks describe the structure of many socio-economic systems. However, in studies of decision-making processes the evolution of the underlying social relations are disregarded. In this report, we aim to understand the formation of self-organizing domains of cooperation (“coalitions”) on an acquaintance network. We include both the network’s influence on the formation of coalitions and vice versa how the network adapts to the current coalition structure, thus forming a social feedback loop. We increase complexity from simple opinion adaptation processes studied in earlier research to more complex decision-making determined by costs and benefits, and from bilateral to multilateral cooperation. We show how phase transitions emerge from such coevolutionary dynamics, which can be interpreted as processes of great transformations. If the network adaptation rate is high, the social dynamics prevent the formation of a grand coalition and therefore full cooperation. We find some empirical support for our main results: Our model develops a bimodal coalition size distribution over time similar to those found in social structures. Our detection and distinguishing of phase transitions may be exemplary for other models of socio-economic systems with low agent numbers and therefore strong finite-size effects.

  18. The catalytic role of uranyl in formation of polycatechol complexes

    Directory of Open Access Journals (Sweden)

    Halada Gary P

    2011-03-01

    Full Text Available Abstract To better understand the association of contaminant uranium with natural organic matter (NOM and the fate of uranium in ground water, spectroscopic studies of uranium complexation with catechol were conducted. Catechol provides a model for ubiquitous functional groups present in NOM. Liquid samples were analyzed using Raman, FTIR, and UV-Vis spectroscopy. Catechol was found to polymerize in presence of uranyl ions. Polymerization in presence of uranyl was compared to reactions in the presence of molybdate, another oxyion, and self polymerization of catechol at high pH. The effect of time and dissolved oxygen were also studied. It was found that oxygen was required for self-polymerization at elevated pH. The potential formation of phenoxy radicals as well as quinones was monitored. The benzene ring was found to be intact after polymerization. No evidence for formation of ether bonds was found, suggesting polymerization was due to formation of C-C bonds between catechol ligands. Uranyl was found to form outer sphere complexes with catechol at initial stages but over time (six months polycatechol complexes were formed and precipitated from solution (forming humic-like material while uranyl ions remained in solution. Our studies show that uranyl acts as a catalyst in catechol-polymerization.

  19. Correlations between community structure and link formation in complex networks.

    Directory of Open Access Journals (Sweden)

    Zhen Liu

    Full Text Available BACKGROUND: Links in complex networks commonly represent specific ties between pairs of nodes, such as protein-protein interactions in biological networks or friendships in social networks. However, understanding the mechanism of link formation in complex networks is a long standing challenge for network analysis and data mining. METHODOLOGY/PRINCIPAL FINDINGS: Links in complex networks have a tendency to cluster locally and form so-called communities. This widely existed phenomenon reflects some underlying mechanism of link formation. To study the correlations between community structure and link formation, we present a general computational framework including a theory for network partitioning and link probability estimation. Our approach enables us to accurately identify missing links in partially observed networks in an efficient way. The links having high connection likelihoods in the communities reveal that links are formed preferentially to create cliques and accordingly promote the clustering level of the communities. The experimental results verify that such a mechanism can be well captured by our approach. CONCLUSIONS/SIGNIFICANCE: Our findings provide a new insight into understanding how links are created in the communities. The computational framework opens a wide range of possibilities to develop new approaches and applications, such as community detection and missing link prediction.

  20. Segrosome complex formation during DNA trafficking in bacterial cell division

    Directory of Open Access Journals (Sweden)

    Maria A. Oliva

    2016-09-01

    Full Text Available Bacterial extrachromosomal DNAs often contribute to virulence in pathogenic organisms or facilitate adaptation to particular environments. The transmission of genetic information from one generation to the next requires sufficient partitioning of DNA molecules to ensure that at least one copy reaches each side of the division plane and is inherited by the daughter cells. Segregation of the bacterial chromosome occurs during or after replication and probably involves a strategy in which several protein complexes participate to modify the folding pattern and distribution first of the origin domain and then of the rest of the chromosome. Low-copy number plasmids rely on specialised partitioning systems, which in some cases use a mechanism that show striking similarity to eukaryotic DNA segregation. Overall, there have been multiple systems implicated in the dynamic transport of DNA cargo to a new cellular position during the cell cycle but most seem to share a common initial DNA partitioning step, involving the formation of a nucleoprotein complex called the segrosome. The particular features and complex topologies of individual segrosomes depend on both the nature of the DNA binding protein involved and on the recognized centromeric DNA sequence, both of which vary across systems. The combination of in vivo and in vitro approaches, with structural biology has significantly furthered our understanding of the mechanisms underlying DNA trafficking in bacteria. Here, I discuss recent advances and the molecular details of the DNA segregation machinery, focusing on the formation of the segrosome complex.

  1. Nanoparticle-protein complexes mimicking corona formation in ocular environment.

    Science.gov (United States)

    Jo, Dong Hyun; Kim, Jin Hyoung; Son, Jin Gyeong; Dan, Ki Soon; Song, Sang Hoon; Lee, Tae Geol; Kim, Jeong Hun

    2016-12-01

    Nanoparticles adsorb biomolecules to form corona upon entering the biological environment. In this study, tissue-specific corona formation is provided as a way of controlling protein interaction with nanoparticles in vivo. In the vitreous, the composition of the corona was determined by the electrostatic and hydrophobic properties of the associated proteins, regardless of the material (gold and silica) or size (20- and 100-nm diameter) of the nanoparticles. To control protein adsorption, we pre-incubate 20-nm gold nanoparticles with 5 selectively enriched proteins from the corona, formed in the vitreous, to produce nanoparticle-protein complexes. Compared to bare nanoparticles, nanoparticle-protein complexes demonstrate improved binding to vascular endothelial growth factor (VEGF) in the vitreous. Furthermore, nanoparticle-protein complexes retain in vitro anti-angiogenic properties of bare nanoparticles. In particular, priming the nanoparticles (gold and silica) with tissue-specific corona proteins allows nanoparticle-protein complexes to exert better in vivo therapeutic effects by higher binding to VEGF than bare nanoparticles. These results suggest that controlled corona formation that mimics in vivo processes may be useful in the therapeutic use of nanomaterials in local environment.

  2. Complex formation between polyelectrolytes and oppositely charged oligoelectrolytes

    Science.gov (United States)

    Zhou, Jiajia; Barz, Matthias; Schmid, Friederike

    2016-04-01

    We study the complex formation between one long polyanion chain and many short oligocation chains by computer simulations. We employ a coarse-grained bead-spring model for the polyelectrolyte chains and model explicitly the small salt ions. We systematically vary the concentration and the length of the oligocation and examine how the oligocations affects the chain conformation, the static structure factor, the radial and axial distribution of various charged species, and the number of bound ions in the complex. At low oligocation concentration, the polyanion has an extended structure. Upon increasing the oligocation concentration, the polyanion chain collapses and forms a compact globule, but the complex still carries a net negative charge. Once the total charge of the oligocations is equal to that of the polyanion, the collapse stops and is replaced by a slow expansion. In this regime, the net charge on the complexes is positive or neutral, depending on the microion concentration in solution. The expansion can be explained by the reduction of the oligocation bridging. We find that the behavior and the structure of the complex are largely independent of the length of oligocations, and very similar to that observed when replacing the oligocations by multivalent salt cations, and conclude that the main driving force keeping the complex together is the release of monovalent counterions and coions. We speculate on the implications of this finding for the problem of controlled oligolyte release and oligolyte substitution.

  3. Cu(II) complex formation with xylitol in alkaline solutions.

    Science.gov (United States)

    Norkus, Eugenijus; Vaiciūniene, Jūrate; Vuorinen, Tapani; Gaidamauskas, Ernestas; Reklaitis, Jonas; Jääskeläinen, Anna-Stiina; Crans, Debbie C

    2004-02-25

    The formation of four Cu(II)-xylitol complexes was observed in aqueous alkaline solutions (11.0 or =10), whereas dinuclear complex Cu2Xyl (log beta=29.2 +/- 0.3) is the predominant species at low ligand-to-metal ratio (L:M=0.5). Diffusion coefficients and molar absorptivities of the complex species were determined. pH variable 13C NMR suggested that pKa values of xylitol are rather similar and equal to 13.8 +/- 0.2, 13.9 +/- 0.1 and 13.9 +/- 0.2 for OH-groups adjacent to (C-1,C-5), (C-3) and (C-2,C-4) carbon atoms, respectively.

  4. Co-infusion of haplo-identical CD19-chimeric antigen receptor T cells and stem cells achieved full donor engraftment in refractory acute lymphoblastic leukemia

    Directory of Open Access Journals (Sweden)

    Bo Cai

    2016-11-01

    Full Text Available Abstract Background Elderly patients with relapsed and refractory acute lymphoblastic leukemia (ALL have poor prognosis. Autologous CD19 chimeric antigen receptor-modified T (CAR-T cells have potentials to cure patients with B cell ALL; however, safety and efficacy of allogeneic CD19 CAR-T cells are still undetermined. Case presentation We treated a 71-year-old female with relapsed and refractory ALL who received co-infusion of haplo-identical donor-derived CD19-directed CAR-T cells and mobilized peripheral blood stem cells (PBSC following induction chemotherapy. Undetectable minimal residual disease by flow cytometry was achieved, and full donor cell engraftment was established. The transient release of cytokines and mild fever were detected. Significantly elevated serum lactate dehydrogenase, alanine transaminase, bilirubin and glutamic-oxalacetic transaminase were observed from days 14 to 18, all of which were reversible after immunosuppressive therapy. Conclusions Our preliminary results suggest that co-infusion of haplo-identical donor-derived CAR-T cells and mobilized PBSCs may induce full donor engraftment in relapsed and refractory ALL including elderly patients, but complications related to donor cell infusions should still be cautioned. Trial registration Allogeneic CART-19 for Elderly Relapsed/Refractory CD19+ ALL. NCT02799550

  5. Titanium complex formation of organic ligands in titania gels.

    Science.gov (United States)

    Nishikiori, Hiromasa; Todoroki, Kenta; Setiawan, Rudi Agus; Teshima, Katsuya; Fujii, Tsuneo; Satozono, Hiroshi

    2015-01-27

    Thin films of organic ligand-dispersing titania gels were prepared from titanium alkoxide sols containing ligand molecules by steam treatment without heating. The formation of the ligand-titanium complex and the photoinduced electron transfer process in the systems were investigated by photoelectrochemical measurements. The complex was formed between the 8-hydroxyquinoline (HQ) and titanium species, such as the titanium ion, on the titania nanoparticle surface through the oxygen and nitrogen atoms of the quinolate. A photocurrent was observed in the electrodes containing the complex due to the electron injection from the LUMO of the complex into the titania conduction band. A bidentate ligand, 2,3-dihydroxynaphthalene (DHN), formed the complex on the titania surface through dehydration between its two hydroxyl groups of DHN and two TiOH groups of the titania. The electron injection from the HOMO of DHN to the titania conduction band was observed during light irradiation. This direct electron injection was more effective than the two-step electron injection.

  6. The ribosome-associated complex antagonizes prion formation in yeast.

    Science.gov (United States)

    Amor, Alvaro J; Castanzo, Dominic T; Delany, Sean P; Selechnik, Daniel M; van Ooy, Alex; Cameron, Dale M

    2015-01-01

    The number of known fungal proteins capable of switching between alternative stable conformations is steadily increasing, suggesting that a prion-like mechanism may be broadly utilized as a means to propagate altered cellular states. To gain insight into the mechanisms by which cells regulate prion formation and toxicity we examined the role of the yeast ribosome-associated complex (RAC) in modulating both the formation of the [PSI(+)] prion - an alternative conformer of Sup35 protein - and the toxicity of aggregation-prone polypeptides. The Hsp40 RAC chaperone Zuo1 anchors the RAC to ribosomes and stimulates the ATPase activity of the Hsp70 chaperone Ssb. We found that cells lacking Zuo1 are sensitive to over-expression of some aggregation-prone proteins, including the Sup35 prion domain, suggesting that co-translational protein misfolding increases in Δzuo1 strains. Consistent with this finding, Δzuo1 cells exhibit higher frequencies of spontaneous and induced prion formation. Cells expressing mutant forms of Zuo1 lacking either a C-terminal charged region required for ribosome association, or the J-domain responsible for Ssb ATPase stimulation, exhibit similarly high frequencies of prion formation. Our findings are consistent with a role for the RAC in chaperoning nascent Sup35 to regulate folding of the N-terminal prion domain as it emerges from the ribosome.

  7. Simulations of photochemical smog formation in complex urban areas

    Science.gov (United States)

    Muilwijk, C.; Schrijvers, P. J. C.; Wuerz, S.; Kenjereš, S.

    2016-12-01

    In the present study we numerically investigated the dispersion of photochemical reactive pollutants in complex urban areas by applying an integrated Computational Fluid Dynamics (CFD) and Computational Reaction Dynamics (CRD) approach. To model chemical reactions involved in smog generation, the Generic Reaction Set (GRS) approach is used. The GRS model was selected since it does not require detailed modeling of a large set of reactive components. Smog formation is modeled first in the case of an intensive traffic emission, subjected to low to moderate wind conditions in an idealized two-dimensional street canyon with a building aspect ratio (height/width) of one. It is found that Reactive Organic Components (ROC) play an important role in the chemistry of smog formation. In contrast to the NOx/O3 photochemical steady state model that predicts a depletion of the (ground level) ozone, the GRS model predicts generation of ozone. Secondly, the effect of direct sunlight and shadow within the street canyon on the chemical reaction dynamics is investigated for three characteristic solar angles (morning, midday and afternoon). Large differences of up to one order of magnitude are found in the ozone production for different solar angles. As a proof of concept for real urban areas, the integrated CFD/CRD approach is applied for a real scale (1 × 1 km2) complex urban area (a district of the city of Rotterdam, The Netherlands) with high traffic emissions. The predicted pollutant concentration levels give realistic values that correspond to moderate to heavy smog. It is concluded that the integrated CFD/CRD method with the GRS model of chemical reactions is both accurate and numerically robust, and can be used for modeling of smog formation in complex urban areas.

  8. Formation of gold mineralization in ultramafic alkalic magmatic complexes

    Science.gov (United States)

    Ryabchikov, I. D.; Kogarko, L. N.; Sazonov, A. M.; Kononkova, N. N.

    2016-06-01

    Study of mineral inclusions within alluvial gold particles of the Guli Complex (East Siberia) and findings of lode gold in rocks of the same intrusion have demonstrated that gold mineralization occurs in interstitions of both early high-magnesium rocks (dunite) and later alkalic and carbonatite rocks. In dunite the native gold occurs in association with Fe-Ni sulfides (monosulfide solid solution, pentlandite, and heazlewoodite). Formation of the gold-bearing alloys took place under a low oxygen potential over a broad range of temperatures: from those close to 600°C down to below 400°C.

  9. Formation and characterization of thioglycolic acid-silver cluster complexes.

    Science.gov (United States)

    Bellina, Bruno; Antoine, Rodolphe; Broyer, Michel; Gell, Lars; Sanader, Željka; Mitrić, Roland; Bonačić-Koutecký, Vlasta; Dugourd, Philippe

    2013-06-21

    Gas phase reactivity observed in an ion trap was used to produce silver clusters protected with thioglycolic acid. Fragmentation pathways as well as optical properties were explored experimentally and theoretically. Sequential losses of SCH2 and CO2 in the ion trap lead to redox reactions with charge transfers between the metal part and the carboxylate and thiolate groups. This allows us to control the number of electrons in the metallic subunit and thus optical properties of the complexes. The presented formation process can be used as a prototype for tuning optical and chemical properties of ligated metal clusters by varying the number of confined electrons within the metallic subunit.

  10. Characterization of Hydrogen Complex Formation in III-V Semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Michael D

    2006-09-28

    Atomic hydrogen has been found to react with some impurity species in semiconductors. Hydrogenation is a methodology for the introduction of atomic hydrogen into the semiconductor for the express purpose of forming complexes within the material. Efforts to develop hydrogenation as an isolation technique for AlGaAs and Si based devices failed to demonstrate its commercial viability. This was due in large measure to the low activation energies of the formed complexes. Recent studies of dopant passivation in long wavelength (0.98 - 1.55m) materials suggested that for the appropriate choice of dopants much higher activation energies can be obtained. This effort studied the formation of these complexes in InP, This material is extensively used in optoelectronics, i.e., lasers, modulators and detectors. The experimental techniques were general to the extent that the results can be applied to other areas such as sensor technology, photovoltaics and to other material systems. The activation energies for the complexes have been determined and are reported in the scientific literature. The hydrogenation process has been shown by us to have a profound effect on the electronic structure of the materials and was thoroughly investigated. The information obtained will be useful in assessing the long term reliability of device structures fabricated using this phenomenon and in determining new device functionalities.

  11. Formation of Soft Nanoparticles via Polyelectrolyte Complexation: A Viscometric Study

    Directory of Open Access Journals (Sweden)

    Rondon Céline

    2014-05-01

    Full Text Available This paper describes the formation of soft nanoparticles resulting from electrostatically driven complexation of oppositely charged polyelectrolytes. The system was composed of a strong polyanion (polystyrene sulfonate, PSS and a weak polycation (poly(allylamine hydrochloride, PAH in large excess. Soft nanoparticles were obtained by pouring a PSS solution into a PAH one under constant stirring. The polyelectrolyte complexes (PEC were characterized through a viscometric study complemented by Dynamic Light Scattering (DLS, electrophoretic mobility and suspension turbidity measurements. PEC suspensions were centrifuged and by measuring the viscosity of the supernatant, we were able to estimate the free polycation concentration and hence the percentage of complexed polycation. We also measured the relative viscosity of the suspensions; from the estimated contribution of the PEC particles and of the polycation in excess, the average particle volume fraction was estimated. From all viscometric data, we could derive the evolution of the binding stoichiometry in PEC and of the effective particle volume fraction as a function of the mixing ratio (ratio of the cationic to anionic groups and of the pH. Our results emphasize the importance of charge accessibility in controlling both the stoichiometry and packing density of the complexes.

  12. Star Formation in the Orion-Monoceros Complex

    CERN Document Server

    Chen Hsu Tai

    2006-01-01

    Pre-main sequence stars in the Orion-Monoceros Complex are either distributed in groups closed associated with dense cores, or dispersed along molecular filaments. Some molecular clouds are apparently affected by the Orion-Eridanus Superbubble created by the Wolf-Rayet winds and supernovae from the Ori OB1 association, whose shock fronts compressed and triggered starbirth in adjacent molecular clouds. We present evidence of a formation sequence from the older star association Ori OB1a, which no longer is associated with molecular gas, to Ori OB1b and 1c, which are associated respectively with Orion A and B molecular clouds, and eventually to Ori OB1d currently active in star formation. The Orion-Eridanus Superbubble continues to spread out to NGC 2149, vdB 64, and the Crossbones, and likely also to Mon R2. The triggering by ionization or the superbubble--both consequences of massive stars--would produce stars and disperse molecular clouds much more efficiently than isolation star formation via spontaneous clo...

  13. 葡聚糖硫酸钠(DSS)诱导的小鼠肠炎模型中CD19+CD5+CD1dhiB细胞的表达及抑炎作用%The role of CD19+CD5+CD1dhi B cells in dextran sulfact sodium (DSS)induced inflammatory bowel disease C57BL/6 mouse model

    Institute of Scientific and Technical Information of China (English)

    汪路曼; 钱静; 刘小明; 常丽君; 储以微

    2013-01-01

    目的 探讨CD19+ CD5+ CD1dhiB细胞在葡聚糖硫酸钠(dextran sulfact sodium,DSS)诱导的C57BL/6小鼠肠炎模型中的表达及抑炎作用.方法 建立DSS诱导的小鼠肠炎模型(n=200),获取疾病不同阶段的脾淋巴细胞,流式细胞仪检测CD19+ CD5+ CD1 dhiB细胞的比例变化;体内转输该群细胞至疾病小鼠,观察小鼠肠炎临床评分以及肠道局部炎性因子分泌的变化.结果 在小鼠肠炎的急性期(第0~10天),CD19+ CD5+CD1 dhiB细胞比例明显增多,在肠炎消退期(第12天),其比例恢复到正常水平;转输疾病急性期(第8天)的CD19+ CD5+ CD1 dhiB细胞可有效控制疾病的进展,缓解病程;ELISA检测提示转输急性期的该群细胞可显著抑制肠道局部促炎细胞因子IFN-γ、TNF-α和IL-6的分泌.结论 DSS诱导的小鼠肠炎中CD19+ CD5+ CD1 dhiB细胞比例随病程发生改变,并可通过抑制肠道局部炎性细胞因子的分泌缓解病症.%Objective To investigate the change in cell number of CD19 + CD5+ Cdldhi B cells and its function in dextran sulfate sodium (DSS) induced inflammatory bowel disease (IBD) C57BL/6 mouse model. Methods The murine model of inflammatory bowel disease was set up by DSS treatment. Splenic CD19+ CD5+ Cdldhi B cells were harvested from mice during different disease stages,and were analyzed by flow cytometry. CD19+ CD5+ Cdldhi B cells were adoptively transferred to the DSS-treated mice, then clinical symptom was evaluated and the production of inflammatory cytokines in local intestine was detected. Results The proportion of CD19+ CD5+ Cdldhi B cells was increased in the acute phase (Day 0 - 10) of the disease and returned to baseline in the recovery phase (Day 12). Adoptive transfer of CD19+ CD5+ Cdldhi B cells from mice in acute phase (Day 8) remarkably inhibited the production of proinflammatory cytokines (IFN-γ, TNF-α and IL-6) in local intestine and resolved the inflammation. Conclusions The proportion of CD19+ CD5+ Cdldhi B

  14. Dynamical complexity in the perception-based network formation model

    Science.gov (United States)

    Jo, Hang-Hyun; Moon, Eunyoung

    2016-12-01

    Many link formation mechanisms for the evolution of social networks have been successful to reproduce various empirical findings in social networks. However, they have largely ignored the fact that individuals make decisions on whether to create links to other individuals based on cost and benefit of linking, and the fact that individuals may use perception of the network in their decision making. In this paper, we study the evolution of social networks in terms of perception-based strategic link formation. Here each individual has her own perception of the actual network, and uses it to decide whether to create a link to another individual. An individual with the least perception accuracy can benefit from updating her perception using that of the most accurate individual via a new link. This benefit is compared to the cost of linking in decision making. Once a new link is created, it affects the accuracies of other individuals' perceptions, leading to a further evolution of the actual network. As for initial actual networks, we consider both homogeneous and heterogeneous cases. The homogeneous initial actual network is modeled by Erdős-Rényi (ER) random networks, while we take a star network for the heterogeneous case. In any cases, individual perceptions of the actual network are modeled by ER random networks with controllable linking probability. Then the stable link density of the actual network is found to show discontinuous transitions or jumps according to the cost of linking. As the number of jumps is the consequence of the dynamical complexity, we discuss the effect of initial conditions on the number of jumps to find that the dynamical complexity strongly depends on how much individuals initially overestimate or underestimate the link density of the actual network. For the heterogeneous case, the role of the highly connected individual as an information spreader is also discussed.

  15. Manufacture of clinical-grade CD19-specific T cells stably expressing chimeric antigen receptor using Sleeping Beauty system and artificial antigen presenting cells.

    Directory of Open Access Journals (Sweden)

    Harjeet Singh

    Full Text Available Adoptive transfer of T cells expressing a CD19-specific chimeric antigen receptor (CAR is being evaluated in multiple clinical trials. Our current approach to adoptive immunotherapy is based on a second generation CAR (designated CD19RCD28 that signals through a CD28 and CD3-ζ endodomain. T cells are electroporated with DNA plasmids from the Sleeping Beauty (SB transposon/transposase system to express this CAR. Stable integrants of genetically modified T cells can then be retrieved when co-cultured with designer artificial antigen presenting cells (aAPC in the presence of interleukin (IL-2 and 21. Here, we reveal how the platform technologies of SB-mediated transposition and CAR-dependent propagation on aAPC were adapted for human application. Indeed, we have initiated clinical trials in patients with high-risk B-lineage malignancies undergoing autologous and allogeneic hematopoietic stem-cell transplantation (HSCT. We describe the process to manufacture clinical grade CD19-specific T cells derived from healthy donors. Three validation runs were completed in compliance with current good manufacturing practice for Phase I/II trials demonstrating that by 28 days of co-culture on γ-irradiated aAPC ∼10(10 T cells were produced of which >95% expressed CAR. These genetically modified and propagated T cells met all quality control testing and release criteria in support of infusion.

  16. BIP induces mice CD19(hi) regulatory B cells producing IL-10 and highly expressing PD-L1, FasL.

    Science.gov (United States)

    Tang, Youfa; Jiang, Qing; Ou, Yanghui; Zhang, Fan; Qing, Kai; Sun, Yuanli; Lu, Wenjie; Zhu, Huifen; Gong, Feili; Lei, Ping; Shen, Guanxin

    2016-01-01

    Many studies have shown that B cells possess a regulatory function in mouse models of autoimmune diseases. Regulatory B cells can modulate immune response through many types of molecular mechanisms, including the production of IL-10 and the expression of PD-1 Ligand and Fas Ligand, but the microenvironmental factors and mechanisms that induce regulatory B cells have not been fully identified. BIP (binding immunoglobulin protein), a member of the heat shock protein 70 family, is a type of evolutionarily highly conserved protein. In this article, we have found that IL-10(+), PD-L1(hi) and FasL(hi) B cells are discrete cell populations, but enriched in CD19(hi) cells. BIP can induce IL-10-producing splenic B cells, IL-10 secretion and B cells highly expressing PD-L1 and FasL. CD40 signaling acts in synergy with BIP to induce regulatory B cells. BIP increased surface CD19 molecule expression intensity and IL-10(+), PD-L1(hi) and FasL(hi) B cells induced by BIP share the CD19(hi) phenotype. Furthermore, B cells treated with BIP and anti-CD40 can lead to suppression of T cell proliferation and the effect is partially IL-10-dependent and mainly BIP-induced. Taken together, our findings identify a novel function of BIP in the induction of regulatory B cells and add a new reason for the therapy of autoimmune disorders or other inflammatory conditions.

  17. Changes in protein structure at the interface accompanying complex formation

    Directory of Open Access Journals (Sweden)

    Devlina Chakravarty

    2015-11-01

    Full Text Available Protein interactions are essential in all biological processes. The changes brought about in the structure when a free component forms a complex with another molecule need to be characterized for a proper understanding of molecular recognition as well as for the successful implementation of docking algorithms. Here, unbound (U and bound (B forms of protein structures from the Protein–Protein Interaction Affinity Database are compared in order to enumerate the changes that occur at the interface atoms/residues in terms of the solvent-accessible surface area (ASA, secondary structure, temperature factors (B factors and disorder-to-order transitions. It is found that the interface atoms optimize contacts with the atoms in the partner protein, which leads to an increase in their ASA in the bound interface in the majority (69% of the proteins when compared with the unbound interface, and this is independent of the root-mean-square deviation between the U and B forms. Changes in secondary structure during the transition indicate a likely extension of helices and strands at the expense of turns and coils. A reduction in flexibility during complex formation is reflected in the decrease in B factors of the interface residues on going from the U form to the B form. There is, however, no distinction in flexibility between the interface and the surface in the monomeric structure, thereby highlighting the potential problem of using B factors for the prediction of binding sites in the unbound form for docking another protein. 16% of the proteins have missing (disordered residues in the U form which are observed (ordered in the B form, mostly with an irregular conformation; the data set also shows differences in the composition of interface and non-interface residues in the disordered polypeptide segments as well as differences in their surface burial.

  18. Formation of STIM and Orai complexes: puncta and distal caps.

    Science.gov (United States)

    Barr, Valarie A; Bernot, Kelsie M; Shaffer, Meredith H; Burkhardt, Janis K; Samelson, Lawrence E

    2009-09-01

    In the last few years, great progress has been made in understanding how stromal interacting molecule 1 (STIM1), a protein containing a calcium sensor that is located in the endoplasmic reticulum, and Orai1, a protein that forms a calcium channel in the plasma membrane, interact and give rise to store-operated calcium entry. Pharmacological depletion of calcium stores leads to the formation of clusters containing STIM and Orai that appear to be sites for calcium influx. Similar puncta are also produced in response to physiological stimuli in immune cells. In T cells engaged with antigen-presenting cells, clusters containing STIM and Orai accumulate at the immunological synapse. We recently discovered that in activated T cells, STIM1 and Orai1 also accumulate in cap-like structures opposite the immune synapse at the distal pole of the cell. Both caps and puncta are long-lived stable structures containing STIM1 and Orai1 in close proximity. The function of puncta as sites of calcium influx is clear. We speculate that the caps may provide a secondary site of calcium entry. Alternatively, they may serve as a source of preformed channel complexes that move to new immune synapses as T cells repeatedly engage antigen-presenting cells.

  19. Integrin activation and focal complex formation in cardiac hypertrophy

    Science.gov (United States)

    Laser, M.; Willey, C. D.; Jiang, W.; Cooper, G. 4th; Menick, D. R.; Zile, M. R.; Kuppuswamy, D.

    2000-01-01

    Cardiac hypertrophy is characterized by both remodeling of the extracellular matrix (ECM) and hypertrophic growth of the cardiocytes. Here we show increased expression and cytoskeletal association of the ECM proteins fibronectin and vitronectin in pressure-overloaded feline myocardium. These changes are accompanied by cytoskeletal binding and phosphorylation of focal adhesion kinase (FAK) at Tyr-397 and Tyr-925, c-Src at Tyr-416, recruitment of the adapter proteins p130(Cas), Shc, and Nck, and activation of the extracellular-regulated kinases ERK1/2. A synthetic peptide containing the Arg-Gly-Asp (RGD) motif of fibronectin and vitronectin was used to stimulate adult feline cardiomyocytes cultured on laminin or within a type-I collagen matrix. Whereas cardiocytes under both conditions showed RGD-stimulated ERK1/2 activation, only collagen-embedded cells exhibited cytoskeletal assembly of FAK, c-Src, Nck, and Shc. In RGD-stimulated collagen-embedded cells, FAK was phosphorylated only at Tyr-397 and c-Src association occurred without Tyr-416 phosphorylation and p130(Cas) association. Therefore, c-Src activation is not required for its cytoskeletal binding but may be important for additional phosphorylation of FAK. Overall, our study suggests that multiple signaling pathways originate in pressure-overloaded heart following integrin engagement with ECM proteins, including focal complex formation and ERK1/2 activation, and many of these pathways can be activated in cardiomyocytes via RGD-stimulated integrin activation.

  20. Immunotherapy of non-Hodgkin's lymphoma with a defined ratio of CD8+ and CD4+ CD19-specific chimeric antigen receptor-modified T cells.

    Science.gov (United States)

    Turtle, Cameron J; Hanafi, Laïla-Aïcha; Berger, Carolina; Hudecek, Michael; Pender, Barbara; Robinson, Emily; Hawkins, Reed; Chaney, Colette; Cherian, Sindhu; Chen, Xueyan; Soma, Lorinda; Wood, Brent; Li, Daniel; Heimfeld, Shelly; Riddell, Stanley R; Maloney, David G

    2016-09-07

    CD19-specific chimeric antigen receptor (CAR)-modified T cells have antitumor activity in B cell malignancies, but factors that affect toxicity and efficacy have been difficult to define because of differences in lymphodepletion and heterogeneity of CAR-T cells administered to individual patients. We conducted a clinical trial in which CD19 CAR-T cells were manufactured from defined T cell subsets and administered in a 1:1 CD4(+)/CD8(+) ratio of CAR-T cells to 32 adults with relapsed and/or refractory B cell non-Hodgkin's lymphoma after cyclophosphamide (Cy)-based lymphodepletion chemotherapy with or without fludarabine (Flu). Patients who received Cy/Flu lymphodepletion had increased CAR-T cell expansion and persistence, and higher response rates [50% complete remission (CR), 72% overall response rate (ORR)] than patients who received Cy-based lymphodepletion without Flu (8% CR, 50% ORR). The CR rate in patients treated with Cy/Flu at the maximally tolerated dose was 64% (82% ORR; n = 11). Cy/Flu minimized the effects of an immune response to the murine single-chain variable fragment component of the CAR, which limited CAR-T cell expansion and clinical efficacy in patients who received Cy-based lymphodepletion without Flu. Severe cytokine release syndrome (sCRS) and grade ≥3 neurotoxicity were observed in 13 and 28% of all patients, respectively. Serum biomarkers, one day after CAR-T cell infusion, correlated with subsequent sCRS and neurotoxicity. Immunotherapy with CD19 CAR-T cells in a defined CD4(+)/CD8(+) ratio allowed identification of correlative factors for CAR-T cell expansion, persistence, and toxicity, and facilitated optimization of lymphodepletion that improved disease response and overall and progression-free survival.

  1. Spectroscopic investigation on the inclusion complex formation between amisulpride and γ-cyclodextrin.

    Science.gov (United States)

    Negi, Jeetendra Singh; Singh, Shivpal

    2013-02-15

    The purpose of this research was to investigate inclusion complex formation between poorly soluble drug amisulpride (AMI) and γ-cyclodextrin (γ-CD). The solubility of AMI was enhanced by formation of inclusion complex of AMI with nano-hydrophobic cavity of γ-CD. The stoichiometry of inclusion complex was studied by continuous variation Job's plot method and found 1:1. The binding constant was found 1166.65 M(-1) by Benesi-Hildebrand plot. The molecular docking of AMI and γ-CD was done to investigate complexation. The inclusion complex formation was further confirmed by (1)H NMR and FT-IR, DSC and XRD analysis. The solubility of AMI was increased 3.74 times after inclusion complex formation with γ-CD.

  2. Complexity of gold nanoparticle formation disclosed by dynamics study

    DEFF Research Database (Denmark)

    Engelbrekt, Christian; Jensen, Palle Skovhus; Sørensen, Karsten

    2013-01-01

    Although chemically synthesized gold nanoparticles (AuNPs) from gold salt (HAuCl4) are among the most studied nanomaterials, understanding the formation mechanisms is a challenge mainly due to limited dynamics information. A range of in situ methods with down to millisecond (ms) time resolution...... have been employed in the present report to monitor time-dependent physical and chemical properties in aqueous solution during the chemical synthesis. Chemical synthesis of AuNPs is a reduction process accompanied by release of ions and protons, and formation of solid particles. Dynamic information......]- to form Au atoms during the early stage of the synthesis process. pH- and conductivity-dynamics point further clearly to formation of coating layers on AuNPs and adsorbate exchange between MES and starch. © 2013 American Chemical Society....

  3. Influence of the Hydrophobicity of Polyelectrolytes on Polyelectrolyte Complex Formation and Complex Particle Structure and Shape

    Directory of Open Access Journals (Sweden)

    Gudrun Petzold

    2011-08-01

    Full Text Available Polyelectrolyte complexes (PECs were prepared by structural uniform and strongly charged cationic and anionic modified alternating maleic anhydride copolymers. The hydrophobicity of the polyelectrolytes was changed by the comonomers (ethylene, isobutylene and styrene. Additionally, the n−/n+ ratio of the molar charges of the polyelectrolytes and the procedure of formation were varied. The colloidal stability of the systems and the size, shape, and structure of the PEC particles were investigated by turbidimetry, dynamic light scattering (DLS and atomic force microscopy (AFM. Dynamic light scattering indicates that beside large PEC particle aggregates distinct smaller particles were formed by the copolymers which have the highest hydrophobicity (styrene. These findings could be proved by AFM. Fractal dimension (D, root mean square (RMS roughness and the surface profiles of the PEC particles adsorbed on mica allow the following conclusions: the higher the hydrophobicity of the polyelectrolytes, the broader is the particle size distribution and the minor is the swelling of the PEC particles. Hence, the most compact particles are formed with the very hydrophobic copolymer.

  4. Low Dose Total Body Irradiation Combined With Recombinant CD19-Ligand × Soluble TRAIL Fusion Protein is Highly Effective Against Radiation-resistant B-precursor Acute Lymphoblastic Leukemia in Mice

    Directory of Open Access Journals (Sweden)

    Fatih M. Uckun

    2015-04-01

    Full Text Available In high-risk remission B-precursor acute lymphoblastic leukemia (BPL patients, relapse rates have remained high post-hematopoietic stem cell transplantation (HSCT even after the use of very intensive total body irradiation (TBI-based conditioning regimens, especially in patients with a high “minimal residual disease” (MRD burden. New agents capable of killing radiation-resistant BPL cells and selectively augmenting their radiation sensitivity are therefore urgently needed. We report preclinical proof-of-principle that the potency of radiation therapy against BPL can be augmented by combining radiation with recombinant human CD19-Ligand × soluble TRAIL (“CD19L–sTRAIL” fusion protein. CD19L–sTRAIL consistently killed radiation-resistant primary leukemia cells from BPL patients as well as BPL xenograft cells and their leukemia-initiating in vivo clonogenic fraction. Low dose total body irradiation (TBI combined with CD19L–sTRAIL was highly effective against (1 xenografted CD19+ radiochemotherapy-resistant human BPL in NOD/SCID (NS mice challenged with an otherwise invariably fatal dose of xenograft cells derived from relapsed BPL patients as well as (2 radiation-resistant advanced stage CD19+ murine BPL with lymphomatous features in CD22ΔE12xBCR-ABL double transgenic mice. We hypothesize that the incorporation of CD19L–sTRAIL into the pre-transplant TBI regimens of patients with very high-risk BPL will improve their survival outcome after HSCT.

  5. PEG10 Activation by Co-Stimulation of CXCR5 and CCR7 Essentially Contributes to Resistance to Apoptosis in CD19+CD34+ B Cells from Patients with B Cell Lineage Acute and Chronic Lymphocytic Leukemia

    Institute of Scientific and Technical Information of China (English)

    ChunsongHu; JeiXiong; LinjeiZhang; BaojunHuang; QiupingZhang; QunLi; MingzhenYang; YaouWu; QunWu; QianShen; QingpingGao; KejianZhang; ZhiminSun; JunyanLin; YouxinJin

    2004-01-01

    We investigated CD19+CD34+ and CD19+CD34 B cells from cord blood (CB) and typical patients with B cell lineage acute and chronic lymphocytic leukemia (B-ALL and B-CLL) in terms of expression and functions of CXCR5/CXCL13 and CCR7/CCL19. CXCR5 and CCR7 were selectively frequent expressed on B-ALL, B-CLL and CB CD19+CD34+ B cells, but not on CD19+CD34- B cells. Instead of induction of impressive chemotactic responsiveness, CXCL13 and CCL19 together induced significant resistance to TNF-α-mediated apoptosis in B-ALL and B-CLL but not CB CD19+CD34+ B cells. B-ALL and B-CLL CD19+CD34+ B cells expressed elevatedlevel of Paternally Expressed Gene 10 (PEG10), and CXCL13 and CCL19 together significantly up-regulated PEG10 expression in the cells. We found that CXCL13 and CCL19 together by means of activation of CXCR5 and CCR7 up-regulated PEG10 expression and function, subsequent stabilized caspase-3 and caspase-8 in B-ALL and B-CLL CD19+CD34+ B cells, and rescued the cells from TNF-α-mediated apoptosis. We suggested that normal lymphocytes, especially naive B and T cells, utilized CXCR5/CXCL13 and CCR7/CCL19 for migration, homing, maturation, and cell homeostasis as well as secondary lymphoid tissues organogenesis. Meanwhile certain malignant cells took advantages of CXCR5/CXCL13 and CCR7/CCL19 for infiltration, resistance to apoptosis, and inappropriate proliferation. Cellular & Molecular Immunology.

  6. PEG10 Activation by Co-Stimulation of CXCR5 and CCR7 Essentially Contributes to Resistance to Apoptosis in CD19+CD34+ B Cells from Patients with B Cell Lineage Acute and Chronic Lymphocytic Leukemia

    Institute of Scientific and Technical Information of China (English)

    Chunsong Hu; Qian Shen; Qingping Gao; Kejian Zhang; Zhimin Sun; Junyan Liu; Youxin Jin; Jinquan Tan; Jei Xiong; Linjei zhang; Baojun Huang; Qiuping Zhang; Qun Li; Mingzhen Yang; Yaou Wu; Qun Wu

    2004-01-01

    We investigated CD19+CD34+ and CD19+CD34- B cells from cord blood (CB) and typical patients with B cell lineage acute and chronic lymphocytic leukemia (B-ALL and B-CLL) in terms of expression and functions of CXCR5/CXCL13 and CCR7/CCL19. CXCR5 and CCR7 were selectively frequent expressed on B-ALL, B-CLL and CB CD19+CD34+ B cells, but not on CD19+CD34- B cells. Instead of induction of impressive chemotactic responsiveness, CXCL13 and CCL19 together induced significant resistance to TNF-α-mediated apoptosis in B-ALL and B-CLL but not CB CD19+CD34+ B cells. B-ALL and B-CLL CD19+CD34+ B cells expressed elevated level of Paternally Expressed Gene 10 (PEG10), and CXCL13 and CCL19 together significantly up-regulated PEG10 expression in the cells. We found that CXCL13 and CCL19 together by means of activation of CXCR5 and CCR7 up-regulated PEG10 expression and function, subsequent stabilized caspase-3 and caspase-8 in B-ALL and B-CLL CD19+CD34+ B cells, and rescued the cells from TNF-α-mediated apoptosis. We suggested that normal lymphocytes, especially na(I)ve B and T cells, utilized CXCR5/CXCL13 and CCR7/CCL19 for migration, homing, maturation, and cell homeostasis as well as secondary lymphoid tissues organogenesis.Meanwhile certain malignant cells took advantages of CXCR5/CXCL13 and CCR7/CCL19 for infiltration,resistance to apoptosis, and inappropriate proliferation.

  7. Effects of chemical and enzymatic modifications on starch-linoleic acid complex formation.

    Science.gov (United States)

    Arijaje, Emily Oluwaseun; Wang, Ya-Jane

    2017-02-15

    This study investigated the complexation yield and physicochemical properties of soluble and insoluble starch complexes with linoleic acid when a β-amylase treatment was applied to acetylated and debranched potato starch. The degree of acetylation was generally higher in the soluble complexes than in the insoluble ones. The insoluble complexes from the acetylated starch displayed the V-type pattern, whereas, the soluble complexes displayed a mixture of either the A-/V-type or the B-/V-type pattern. Acetylation decreased onset and peak melting temperatures for the insoluble complexes, whereas no melting endotherm was observed in the soluble complexes. Acetylation substantially increased the amount of complexed linoleic acid in the insoluble complexes, but had little positive effect on the formation of the soluble complexes. The β-amylase treatment significantly increased the complexed linoleic content in both soluble and insoluble complexes for the low acetylated starch, but not for the high acetylated starch.

  8. The Effect of Complex Formation upon the Redox Potentials of Metallic Ions. Cyclic Voltammetry Experiments.

    Science.gov (United States)

    Ibanez, Jorge G.; And Others

    1988-01-01

    Describes experiments in which students prepare in situ soluble complexes of metal ions with different ligands and observe and estimate the change in formal potential that the ion undergoes upon complexation. Discusses student formation and analysis of soluble complexes of two different metal ions with the same ligand. (CW)

  9. Isolation and characterization of unusual multinuclear Schiff base complexes: rearrangements reactions and octanuclear cluster formation.

    Science.gov (United States)

    Martínez Belmonte, Marta; Escudero-Adán, Eduardo C; Martin, Eddy; Kleij, Arjan W

    2012-05-07

    The isolation and full characterization of multinuclear Schiff base complexes is reported, and their relevance as precursors for octanuclear Zn(8) salen cluster complex formation is discussed. Starting from simple precursors, three tetranuclear Zn(4) complexes were accessed that incorporate typical half-salen units and comprise of bridging acetates. The use of alternative reaction conditions or a step-wise approach smoothly leads to Zn(8) cluster formation. In addition, the tetranuclear Zn(4) complexes themselves may also serve as precursors toward Zn(8) cluster formation when treated under appropriate reaction conditions. The influence of the solvent medium in the latter Zn(4) → Zn(8) conversion was separately studied and revealed the formation of unusual pyridine-ligated multinuclear structures with fully condensed salen coordination pockets, providing a possible prelude to octanuclear cluster formation.

  10. Formation of transcription factor complexes during embryonic erythroid development

    NARCIS (Netherlands)

    X. Yu (Xiao)

    2013-01-01

    textabstractHematopoiesis is a classic model for the study of embryonic and adult stem cell differentiation. Erythropoiesis is the process of generating erythrocytes from hematopoietic stem cells (HSC). In Chapter1, we introduce the process of erythropoiesis and discuss proteins and protein complexe

  11. Dimeric interactions and complex formation using direct coevolutionary couplings.

    Science.gov (United States)

    dos Santos, Ricardo N; Morcos, Faruck; Jana, Biman; Andricopulo, Adriano D; Onuchic, José N

    2015-09-04

    We develop a procedure to characterize the association of protein structures into homodimers using coevolutionary couplings extracted from Direct Coupling Analysis (DCA) in combination with Structure Based Models (SBM). Identification of dimerization contacts using DCA is more challenging than intradomain contacts since direct couplings are mixed with monomeric contacts. Therefore a systematic way to extract dimerization signals has been elusive. We provide evidence that the prediction of homodimeric complexes is possible with high accuracy for all the cases we studied which have rich sequence information. For the most accurate conformations of the structurally diverse dimeric complexes studied the mean and interfacial RMSDs are 1.95Å and 1.44Å, respectively. This methodology is also able to identify distinct dimerization conformations as for the case of the family of response regulators, which dimerize upon activation. The identification of dimeric complexes can provide interesting molecular insights in the construction of large oligomeric complexes and be useful in the study of aggregation related diseases like Alzheimer's or Parkinson's.

  12. Coexistence facilitates interspecific biofilm formation in complex microbial communities

    DEFF Research Database (Denmark)

    Madsen, Jonas Stenløkke; Røder, Henriette Lyng; Russel, Jakob

    2016-01-01

    Social interactions in which bacteria respond to one another by modifying their phenotype are central determinants of microbial communities. It is known that interspecific interactions influence the biofilm phenotype of bacteria; a phenotype that is central to the fitness of bacteria. However...... correlated with an increase in planktonic cell numbers, thus implying a behavioral response rather than mere growth competition. Our findings suggest that an increase in biofilm formation is a common adaptive response to long-term coexistence....

  13. Flow induced streamer formation in particle laden complex flows

    Science.gov (United States)

    Debnath, Nandini; Hassanpourfard, Mahtab; Ghosh, Ranajay; Trivedi, Japan; Thundat, Thomas; Kumar, Aloke

    2016-11-01

    We study the combined flow of a polyacrylamide (PAM)solution with polystyrene (PS) nanoparticles, through a microfluidic device containing an array of micropillars. The flow is characterized by a very low Reynolds number (Re= 20), PS nanoparticles localize near pillar walls to form thin slender string-like structures, which we call 'streamers' due to their morphology. Post-formation, these streamers show significant viscous behavior for short observational time-scales, and at longer observational time scales elastic response dominates. Our abiotic streamers could provide a framework for understanding similar structures that often form in biological systems. PhD student, Department of Mechanical Engineering.

  14. Collectin-11/MASP complex formation triggers activation of the lectin complement pathway--the fifth lectin pathway initiation complex

    DEFF Research Database (Denmark)

    Ma, Ying Jie; Skjoedt, Mikkel-Ole; Garred, Peter

    2013-01-01

    complement pathway regulator MAP-1. Furthermore, we found that complex formation between recombinant collectin-11 and recombinant MASP-2 on Candida albicans leads to deposition of C4b. Native collectin-11 in serum mediated complement activation and deposition of C4b and C3b, and formation of the terminal...... complement complex on C. albicans. Moreover, spiking collectin-11-depleted serum, which did not mediate complement activation, with recombinant collectin-11 restored the complement activation capability. These results define collectin-11 as the fifth recognition molecule in the lectin complement pathway...

  15. Protein-free parallel triple-stranded DNA complex formation

    Science.gov (United States)

    Shchyolkina, A. K.; Timofeev, E. N.; Lysov, Yu. P.; Florentiev, V. L.; Jovin, T. M.; Arndt-Jovin, D. J.

    2001-01-01

    A 14 nt DNA sequence 5′-AGAATGTGGCAAAG-3′ from the zinc finger repeat of the human KRAB zinc finger protein gene ZNF91 bearing the intercalator 2-methoxy,6-chloro,9-amino acridine (Acr) attached to the sugar–phosphate backbone in various positions has been shown to form a specific triple helix (triplex) with a 16 bp hairpin (intramolecular) or a two-stranded (intermolecular) duplex having the identical sequence in the same (parallel) orientation. Intramolecular targets with the identical sequence in the antiparallel orientation and a non-specific target sequence were tested as controls. Apparent binding constants for formation of the triplex were determined by quantitating electrophoretic band shifts. Binding of the single-stranded oligonucleotide probe sequence to the target led to an increase in the fluorescence anisotropy of acridine. The parallel orientation of the two identical sequence segments was confirmed by measurement of fluorescence resonance energy transfer between the acridine on the 5′-end of the probe strand as donor and BODIPY-Texas Red on the 3′-amino group of either strand of the target duplex as acceptor. There was full protection from OsO4-bipyridine modification of thymines in the probe strand of the triplex, in accordance with the presumed triplex formation, which excluded displacement of the homologous duplex strand by the probe–intercalator conjugate. The implications of these results for the existence of protein-independent parallel triplexes are discussed. PMID:11160932

  16. Investigation of complex formation processes of hydroxypropylmethylcellulose and polymethacrylic acid in aqueous solutions

    Directory of Open Access Journals (Sweden)

    M. Katayeva

    2012-12-01

    Full Text Available The complex formation process of hydroxypropylcellulose (HPC with polymethacrylic acid (PMA have been studied using methods of turbidimetric and viscosimetric titration. Position of maximum depending on polymer concentration and molecular mass of polysaccharide have different values.

  17. Ionic liquid effects on Mizoroki-Heck reactions: more than just carbene complex formation.

    Science.gov (United States)

    Gyton, Matthew R; Cole, Marcus L; Harper, Jason B

    2011-08-28

    Reaction profiles for a Mizoroki-Heck reaction in either an ionic liquid or a molecular solvent with different palladium sources demonstrate that the rate enhancements observed in ionic liquids cannot be solely attributed to Pd-carbene complex formation.

  18. Localization and dynamics of amylose-lipophilic molecules inclusion complex formation in starch granules

    NARCIS (Netherlands)

    Manca, Marianna; Woortman, Albert J. J.; Mura, Andrea; Loos, Katja; Loi, Maria Antonietta

    2015-01-01

    Inclusion complex formation between lipophilic dye molecules and amylose polymers in starch granules is investigated using laser spectroscopy and microscopy. By combining confocal laser scanning microscopy (CLSM) with spatial resolved photoluminescence (PL) spectroscopy, we are able to discriminate

  19. OTDM-to-WDM Conversion of Complex Modulation Formats by Time-Domain Optical Fourier Transformation

    DEFF Research Database (Denmark)

    Palushani, Evarist; Richter, T.; Ludwig, R.

    2012-01-01

    We demonstrate the utilization of the optical Fourier transform technique for serial-to-parallel conversion of 64×10-GBd OTDM data tributaries with complex modulation formats into 50-GHz DWDM grid without loss of phase and amplitude information.......We demonstrate the utilization of the optical Fourier transform technique for serial-to-parallel conversion of 64×10-GBd OTDM data tributaries with complex modulation formats into 50-GHz DWDM grid without loss of phase and amplitude information....

  20. Formation of complex anodic films on porous alumina matrices

    Indian Academy of Sciences (India)

    Alexander Zahariev; Assen Girginov

    2003-04-01

    The kinetics of growth of complex anodic alumina films was investigated. These films were formed by filling porous oxide films (matrices) having deep pores. The porous films (matrices) were obtained voltastatically in (COOH)2 aqueous solution under various voltages. The filling was done by re-anodization in an electrolyte solution not dissolving the film. Data about the kinetics of re-anodization depending on the porosity of the matrices were obtained. On the other hand, the slopes of the kinetic curves during reanodization were calculated by two equations expressing the dependence of these slopes on the ionic current density. A discrepancy was ascertained between the values of the calculated slopes and those experimentally found. For this discrepancy a possible explanation is proposed, related to the temperature increase in the film, because of that the real current density significantly increases during re-anodization.

  1. Upregulation of CD19⁺CD24(hi)CD38(hi) regulatory B cells is associated with a reduced risk of acute lung injury in elderly pneumonia patients.

    Science.gov (United States)

    Song, Haihan; Xi, Jianjun; Li, Guang-Gang; Xu, Shumin; Wang, Chunmei; Cheng, Tingting; Li, Hongqiang; Zhang, Ying; Liu, Xiandong; Bai, Jianwen

    2016-04-01

    Acute lung injury (ALI) is a common complication in elderly pneumonia patients who have a rapid progression, and is accompanied by a high mortality rate. Because the treatment options of ALI are limited to supportive care, identifying pneumonia patients who are at higher risk of ALI development is the emphasis of many studies. Here, we approach this problem from an immunological perspective by examining CD19(+)CD24(hi)CD38(hi) B cells, an important participant in acute and chronic inflammation. We find that elderly pneumonia patients have elevated CD19(+)CD24(hi)CD38(hi) B cell frequency compared to healthy individuals. This B cell population may express a higher level of IL-10, which has been was shown to suppress CD4(+) T cell-mediated proinflammatory cytokine interferon gamma (IFNg) and tumor necrosis factor alpha (TNFa) production, through an IL-10-dependent mechanism. We also observe that the frequency of CD19(+)CD24(hi)CD38(hi) B cell is positively correlated with the frequency of CD4(+)CD25(+)Foxp3(+)Tregs in peripheral blood. Moreover, consistent with CD19(+)CD24(hi)CD38(hi) B cell's anti-inflammatory role, we find that pneumonia patients who later developed ALI have reduced level of CD19(+)CD24(hi)CD38(hi) B cells. Together, our results demonstrated that CD19(+)CD24(hi)CD38(hi) B cells in pneumonia patients possess regulatory function in vivo, and are associated with a reduced ALI risk.

  2. SCIENTIFIC PRINCIPLES FOR MODIFICATION OF WATER-SOLUBLE POLYMERS. FORMATION OF MACROMOLECULAR COMPLEXES

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    The study of nanosecond dynamics of macromolecules with the luminescent methods make it possible to investigate the formation and functioning of polymeric complexes, polymeric conjugates and macromolecular metal complexes, which are widely used for solving many practical tasks. The nanosecond dynamics of macromolecules are a highly sensitive indicator of interpolymer complexes (IPC) formation. It enables us to solve the problems of studying IPC formation and stability and to investigate the interpolymer reactions of exchange and substitution. The investigation of changes in the rotational mobility of globular protein molecules as a whole makes it possible to determine the complex composition and its stability, and to control the course of polymer-protein conjugate formstion reaction. The nanosecond dynamics of polymers interacting with surfacants' ions (S)are the sensitive indicator of the S-polymer complex formation. A method for determining the equilibrium constants of the S-polymer complex formation was developed on the basis of the study of polymer chains mobility. It is established that nanosecond dynamics influences the course of chemical reactions in polymer chains. Moreover, the marked effect of the nanosecond dynamics is also revealed in the study of photophysical processes (the formation of excimers and energy migration of electron excitation) in polymers with photoactive groups. It was found that the efficiency of both processes increases with increasing the mobility of side chains, the carriers of photoactive groups.

  3. Complex formation and solubility of Pu(IV) with malonic and succinic acids

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, T.; Kobayashi, T.; Takagi, I.; Moriyama, H. [Kyoto Univ. (Japan). Dept. of Nuclear Engineering; Fujiwara, A. [Radioactive Waste Management Funding and Research Center, Tokyo (Japan); Kulyako, Y.M.; Perevalov, S.A.; Myasoedov, B.F. [Russian Academy of Sciences (RAS), Moscow (RU). V.I. Vernadsky Inst. of Geochemistry and Analytical Chemistry (GEOKHI)

    2009-07-01

    The complex formation constants of tetravalent plutonium ion with malonic and succinic acids in aqueous solution were determined by the solvent-extraction method. Also, by taking the known values of the solubility products, the hydrolysis constants and the formation constants, the experimental solubility data of plutonium in the presence of carboxylates were analyzed. (orig.)

  4. Oxidative peptide /and amide/ formation from Schiff base complexes

    Science.gov (United States)

    Strehler, B. L.; Li, M. P.; Martin, K.; Fliss, H.; Schmid, P.

    1982-01-01

    One hypothesis of the origin of pre-modern forms of life is that the original replicating molecules were specific polypeptides which acted as templates for the assembly of poly-Schiff bases complementary to the template, and that these polymers were then oxidized to peptide linkages, probably by photo-produced oxidants. A double cycle of such anti-parallel complementary replication would yield the original peptide polymer. If this model were valid, the Schiff base between an N-acyl alpha mino aldehyde and an amino acid should yield a dipeptide in aqueous solution in the presence of an appropriate oxidant. In the present study it is shown that the substituted dipeptide, N-acetyl-tyrosyl-tyrosine, is produced in high yield in aqueous solution at pH 9 through the action of H2O2 on the Schiff-base complex between N-acetyl-tyrosinal and tyrosine and that a great variety of N-acyl amino acids are formed from amino acids and aliphatic aldehydes under similar conditions.

  5. Excretion technique of radioactive materials in vivo by complex formation

    Energy Technology Data Exchange (ETDEWEB)

    Takaya, Haruo; Uchiumi, Akira; Takatsu, Akiko [National Inst. of Materials and Chemical Research, Tsukuba, Ibaraki (Japan)

    2000-02-01

    To establish an excretion technique of RI metals ({sup 63}Ni, {sup 109}Cd and {sup 210}Pb) in vivo, many kinds of complexing agents were developed. The performance evaluation of these agents was carried out by mouse in vivo. They are various kinds of carbohydrate formazan derivatives with deduced uni-saccharide (D-glucose, D-mannose and D-galactose) or disaccharide (maltose) and functional group (-COOH, -NH, -OH, -N=N- and pyridyl group). For example of synthesis method of, formazan derivative with maltose was described. 100 mouse with 8 to 10 g were classified to four groups. 1 group get 0.1 ml of nickel ion hemoperitoneum injection once (control). 2 group had 0.1 ml nickel ion hemoperitoneum injection at one time a day and then 0.1 ml eccritic hypodermic injection during 5 days. 3 group get 0.1 ml cadmium ion hemoperitoneum injection once (control). 4 group had 0.1 ml cadmium ion hemoperitoneum injection and then 0.1 ml eccritic hypodermic injection at one time a day for 5 days. Decay of residue was measured. PCF-maltose showed the best chemical protector against radiation in these agents. Especially, this eccritic can excrete {sup 63}Ni and {sup 109}Cd without effect on the essential metals such as calcium, magnesium and iron. (S.Y.)

  6. Structure of soybean serine acetyltransferase and formation of the cysteine regulatory complex as a molecular chaperone

    Science.gov (United States)

    Serine acetyltransferase (SAT) catalyzes the limiting reaction in plant and microbial biosynthesis of cysteine. In addition to its enzymatic function, SAT forms a macromolecular complex with O-acetylserine sulfhydrylase (OASS). Formation of the cysteine regulatory complex (CRC) is a critical biochem...

  7. FORMATION AND ELECTROCHEMICAL BEHAVIOUR OF POLYION COMPLEXES FOR ELECTROCHROMIC DISPLAY MATERIAL

    Institute of Scientific and Technical Information of China (English)

    WAN Guoxiang; WANG Bing; DENG Zhenghua; LUO Chunqiao

    1988-01-01

    Formation of intermacromolecular complexes containing viologen and electron-transfer reaction occurred on the electrode modified by the complex films were studied. Compositions and morphology of the complexes depend on the properties of polyanion and chemical environment of complexation. The analytical results of cyclic voltammetry (CV) and rotating disk voltammetry(RDV) indicated: (1) active sites of viologen in network of complexes transferred single electron reversibly; (2) the redox peak currents showed excellent symmetry and stability; (3) redox potentials were related to properties of polyanions, varying from -0.4 to -0.6V (vs. SCE). Electrochromic materials with different displaying colors could be obtained by changing the structure of polyviologen.

  8. Formation and recondensation of complex organic molecules during protostellar luminosity outbursts

    CERN Document Server

    Taquet, Vianney; Charnley, Steven B

    2016-01-01

    During the formation of stars, the accretion of the surrounding material toward the central object is thought to undergo strong luminosity outbursts, followed by long periods of relative quiescence, even at the early stages of star formation when the protostar is still embedded in a large envelope. We investigated the gas phase formation and the recondensation of the complex organic molecules (COMs) di-methyl ether and methyl formate, induced by sudden ice evaporation processes occurring during luminosity outbursts of different amplitudes in protostellar envelopes. For this purpose, we updated a gas phase chemical network forming complex organic molecules in which ammonia plays a key role. The model calculations presented here demonstrate that ion-molecule reactions alone could account for the observed presence of di-methyl ether and methyl formate in a large fraction of protostellar cores, without recourse to grain-surface chemistry, although they depend on uncertain ice abundances and gas phase reaction bra...

  9. Suilysin-induced Platelet-Neutrophil Complexes Formation is Triggered by Pore Formation-dependent Calcium Influx

    Science.gov (United States)

    Zhang, Shengwei; Zheng, Yuling; Chen, Shaolong; Huang, Shujing; Liu, Keke; Lv, Qingyu; Jiang, Yongqiang; Yuan, Yuan

    2016-01-01

    Platelet activation and platelet–neutrophil interactions have been found to be involved in inflammation, organ failure and soft-tissue necrosis in bacterial infections. Streptococcus suis, an emerging human pathogen, can cause streptococcal toxic-shock syndrome (STSS) similarly to Streptococcus pyogenes. Currently, S. suis–platelet interactions are poorly understood. Here, we found that suilysin (SLY), the S. suis cholesterol-dependent cytolysin (CDC), was the sole stimulus of S. suis that induced platelet-neutrophil complexes (PNC) formation. Furthermore, P-selectin released in α-granules mediated PNC formation. This process was triggered by the SLY-induced pore forming-dependent Ca2+ influx. Moreover, we demonstrated that the Ca2+ influx triggered an MLCK-dependent pathway playing critical roles in P-selectin activation and PNC formation, however, PLC-β-IP3/DAG-MLCK and Rho-ROCK-MLCK signalling were not involved. Additionally, the “outside-in” signalling had a smaller effect on the SLY-induced P-selectin release and PNC formation. Interestingly, other CDCs including pneumolysin and streptolysin O have also been found to induce PNC formation in a pore forming-dependent Ca2+ influx manner. It is possible that the bacterial CDC-mediated PNC formation is a similar response mechanism used by a wide range of bacteria. These findings may provide useful insight for discovering potential therapeutic targets for S. suis-associated STSS. PMID:27830834

  10. Evidence for the formation of a complex between osteopontin and osteocalcin.

    Science.gov (United States)

    Ritter, N M; Farach-Carson, M C; Butler, W T

    1992-08-01

    We hypothesize that the mechanisms governing bone formation and remodeling involve the assembly of some of the components of the extracellular matrix into supramolecular complexes. We have examined the associations of osteopontin (OPN) with other proteins isolated from demineralized rat long bones. Three ligand binding techniques were used to demonstrate the formation of complexes between osteopontin and osteocalcin (OCN). Using gel overlay assays, the binding between soluble 125I-OPN and OCN immobilized in acrylamide gels was visualized. Competition for 125I-OPN-OCN complexes was demonstrated when unlabeled OCN-enriched bone extract was included in gel overlay solutions. Also, gel overlay assays showed 125I-OCN binding to OPN. Saturable binding was shown in solid-phase filter binding assays, which yielded an equilibrium binding constant of moderately high affinity (approximately 10(-8) M). Specificity of OPN-OCN complex formation was confirmed by measuring binding in the presence of unlabeled OPN and OCN versus a bone-localized serum protein, alpha 2HS-glycoprotein. Finally, the formation of soluble complexes were demonstrated in a modified Hummel-Dreyer gel filtration assay. These results indicate that OPN and OCN form complexes in vitro. The possible functions of OPN-OCN complexes in osteoclast recruitment and attachment are discussed.

  11. Late-Stage Reservoir Formation Effect and Its Dynamic Mechanisms in Complex Superimposed Basins

    Institute of Scientific and Technical Information of China (English)

    KANG Dejiang; PANG Xiongqi; KUANG Jun; LUO Xiaorong; PANG Hong; LEI Lei

    2010-01-01

    Complex superimposed basins exhibit multi-stage tectonic events and multi-stage reservoir formation; hydrocarbon reservoirs formed in the early stage have generally late-stage genesis characteristics after undergoing adjustment,reconstruction and destruction of later-stage multiple tectonic events.In this paper,this phenomenon is called the late-stage reservoir formation effect.The late-stage reservoir formation effect is a basic feature of oil and gas-forming reservoirs in complex superimposed basins,revealing not only multi-stage character,relevance and complexity of oil and gas-forming reservoirs in superimposed basins but also the importance of late-stage reservoir formation.Late-stage reservoir formation is not a basic feature of off and gas forming reservoir in superimposed basins.Multi-stage reservoir formation only characterizes one aspect of oil and gas-forming reservoir in superimposed basins and does not represent fully the complexity of oil and gas-forming reservoir in superimposed basins.We suggest using"late-stage reservoir formation effect"to replace the"late-stage reservoir formation"concept to guide the exploration of complex reservoirs in superimposed basins.Under current geologic conditions,the late-stage reservoir formation effect is represented mainly by four basic forms:phase transformation,scale reconstruction,component variation and trap adjustment.The late-stage reservoir formation effect is produced by two kinds of geologic processes:first,the off and gas retention function of various geologic thresholds(hydrocarbon expulsion threshold,hydrocarbon migration threshold,and hydrocarbon accumulating threshold)causes the actual time of oil and gas reservoir formation to be later than the time of generation of large amounts of hydrocarbon in a conventional sense,producing the late-stage reservoir formation effect; second,multiple types of tectonic events(continuously strong reconstruction,early-stage strong reconstruction,middle-stage strong

  12. Complex 3D Vortex Lattice Formation by Phase-Engineered Multiple Beam Interference

    Directory of Open Access Journals (Sweden)

    Jolly Xavier

    2012-01-01

    Full Text Available We present the computational results on the formation of diverse complex 3D vortex lattices by a designed superposition of multiple plane waves. Special combinations of multiples of three noncoplanar plane waves with a designed relative phase shift between one another are perturbed by a nonsingular beam to generate various complex 3D vortex lattice structures. The formation of complex gyrating lattice structures carrying designed vortices by means of relatively phase-engineered plane waves is also computationally investigated. The generated structures are configured with both periodic as well as transversely quasicrystallographic basis, while these whirling complex lattices possess a long-range order of designed symmetry in a given plane. Various computational analytical tools are used to verify the presence of engineered geometry of vortices in these complex 3D vortex lattices.

  13. Comparative thermodynamic study on complex formation of native and hydroxypropylated cyclodextrins with benzoic acid

    Energy Technology Data Exchange (ETDEWEB)

    Terekhova, Irina V., E-mail: ivt@isc-ras.ru [Institute of Solution Chemistry of RAS, Ivanovo (Russian Federation)

    2011-11-10

    Highlights: Black-Right-Pointing-Pointer Comparative calorimetric study on complexation of benzoic acid by native and modified cyclodextrins was performed. Black-Right-Pointing-Pointer Van der Waals interactions are responsible for complex formation with {alpha}-cyclodextrins. Black-Right-Pointing-Pointer Complex formation of {beta}-cyclodextrins is governed by dehydration and hydrophobic interactions. Black-Right-Pointing-Pointer Binding of two benzoic acid molecules by {gamma}-cyclodextrins is driven by van der Waals interactions and solvent reorganization. Black-Right-Pointing-Pointer Hydroxypropyl groups favor binding of benzoic acid only with hydroxypropyl-{beta}-cyclodextrin. - Abstract: Complex formation of native and hydroxypropylated {alpha}-, {beta}- and {gamma}-cyclodextrins with benzoic acid in water was studied by means of calorimetry of solution at 298.15 K. The 1:1 complexes are formed with {alpha}- and {beta}-cyclodextrins, while 1:2 binding stoichiometry was observed for {gamma}-cyclodextrins. Thermodynamic parameters of complex formation of hydroxypropylated cyclodextrins were determined for the first time and analyzed. Comparison of binding affinity of native and modified cyclodextrins was carried out.

  14. FEM simulation of formation of metamorphic core complex with ANSYS software

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This study utilizes ANSYS to establish FEM's model of metamorphic core complex,and used thermal-structure analysis to simulate metamorphic core complex's temperature field and stress field.The metamorphic core complex formation mechanism is discussed.The simulation results show that the temperature field change appearing as the earth surface's temperature is the lowest,and the temperature of metamorphic core complex's nucleus is the highest.The temperature field is higher along with depth increase,and the stress field change appearing as the biggest stress occurs in the nucleus.The next stress field occurs at the top of the cover.

  15. Evolution Methods of Formation of Neuronet Models of Complex Economic Systems

    Directory of Open Access Journals (Sweden)

    Khemelyov Oleksandr H.

    2014-01-01

    Full Text Available The article analyses principles of formation of neuronet models of complex economic systems. It justifies prospectiveness of use of artificial intellect methods when modelling complex economic systems. It shows a possibility of use of evolution methods when forming neuronet models of complex economic systems for ensuring invariance of their generalising properties. It offers an algorithm with a genome from operons of fixed length. It considers all operons from the point of view of functional positions. It notes a specific feature of the algorithm, which allows excluding anthropogenic factors when selecting the neuronet models architecture. It proves adequacy of the formed neuronet models of complex economic systems.

  16. Formation and metamorphic evolution of the Douling Complex from the East Qinling Mountains

    Institute of Scientific and Technical Information of China (English)

    张寿广; 魏春景; 赵子然; 沈洁

    1996-01-01

    The Douling Complex occurs as a Precambrian tectonic block distributed between the North China and Yangtze plates and has a protracted evolutional history. It is composed of various metamorpnic intrusives and supracrustal rocks. According to the studies on geology and geochronology, it can be concluded that the complex may have been formed in the early Proterozoic, about 2000 Ma ago and experienced two phases of regional metamorphism during the Jinningian and late Caledonian-early Hercynian. It can be correlated with the Qinling Complex from the North Qinling Mountains in lithic assemblage, formation age, tectonic setting and metamorphism, and is probably a thrust nappe split from the Qinling Complex.

  17. Egress of CD19(+)CD5(+) cells into peripheral blood following treatment with the Bruton tyrosine kinase inhibitor ibrutinib in mantle cell lymphoma patients.

    Science.gov (United States)

    Chang, Betty Y; Francesco, Michelle; De Rooij, Martin F M; Magadala, Padmaja; Steggerda, Susanne M; Huang, Min Mei; Kuil, Annemieke; Herman, Sarah E M; Chang, Stella; Pals, Steven T; Wilson, Wyndham; Wiestner, Adrian; Spaargaren, Marcel; Buggy, Joseph J; Elias, Laurence

    2013-10-03

    Ibrutinib (PCI-32765) is a highly potent oral Bruton tyrosine kinase (BTK) inhibitor in clinical development for treating B-cell lymphoproliferative diseases. Patients with chronic lymphocytic leukemia (CLL) often show marked, transient increases of circulating CLL cells following ibrutinib treatments, as seen with other inhibitors of the B-cell receptor (BCR) pathway. In a phase 1 study of ibrutinib, we noted similar effects in patients with mantle cell lymphoma (MCL). Here, we characterize the patterns and phenotypes of cells mobilized among patients with MCL and further investigate the mechanism of this effect. Peripheral blood CD19(+)CD5(+) cells from MCL patients were found to have significant reduction in the expression of CXCR4, CD38, and Ki67 after 7 days of treatment. In addition, plasma chemokines such as CCL22, CCL4, and CXCL13 were reduced 40% to 60% after treatment. Mechanistically, ibrutinib inhibited BCR- and chemokine-mediated adhesion and chemotaxis of MCL cell lines and dose-dependently inhibited BCR, stromal cell, and CXCL12/CXCL13 stimulations of pBTK, pPLCγ2, pERK, or pAKT. Importantly, ibrutinib inhibited migration of MCL cells beneath stromal cells in coculture. We propose that BTK is essential for the homing of MCL cells into lymphoid tissues, and its inhibition results in an egress of malignant cells into peripheral blood. This trial was registered at www.clinicaltrials.gov as #NCT00114738.

  18. Complexometric determination: Part I - EDTA and complex formation with the Cu2+ ion

    Directory of Open Access Journals (Sweden)

    Rajković Miloš B.

    2002-01-01

    Full Text Available Compounds forming very stable complexes - chelates, have a wide field of application in analytical chemistry. The most famous group of these compounds are complexons. Complexons represent organic polyaminocarbonic acids as for example ethylenediaminetetraacetic acid (EDTA and its salts. The EDTA molecule has six coordinative sites. It is a hexadentate ligands i.e. it has two binding nitrogen atoms and four oxygen atoms from carboxyl groups and it forms complexes with almost all metal ions. EDTA as a tetraprotonic acid, H4Y disociates through four steps, yielding the ions HsY-, H2Y2-, HY3- and Y4-. Which of the EDTA forms will be encountered in a solution, depends on the pH. Due to the poor solubility of EDTA in pure water, as well as in most organic solvents, the disodium salt of EDTA Na2H2Y-2H2O, under the commercial name complexon III, is utilized for analytical determinations. In water, EDTA forms soluble, stabile chelate complexes with all cations, at the molar ratio 1:1, regardless of the charge of the metal ion. In contrast to other equilibria, which are mainly defined by Le Chatellier's principle, equilibria related to metal-EDTA complex formation are also dependent on the influence of the secondary equilibria of EDTA complex formation. Complexing reactions, which are equilibrium reactions, are simultaneously influenced by the following factors: solution pH and the presence of complexing agents which may also form a stabile complex with metal ions. The secondary reaction influence may be viewed and monitored through conditional stability constants. In the first part of the paper, the reaction of the formation of the Cu2+-ion complex with EDTA is analyzed beginning from the main reaction through various influences of secondary reactions on the complex Cu2+-EDTA: pH effect, complexation effect and hydrolysis effect. The equations are given for conditional stability constants, which include equilibrium reactions under actual conditions.

  19. Circulating (CD3−CD19+CD20−IgD−CD27highCD38high) Plasmablasts: A Promising Cellular Biomarker for Immune Activity for Anti-PLA2R1 Related Membranous Nephropathy?

    Science.gov (United States)

    Beukinga, Ingrid; Willard-Gallo, Karen; Nortier, Joëlle; Pradier, Olivier

    2016-01-01

    Membranous nephropathy (MN) is a kidney specific autoimmune disease mainly mediated by anti-phospholipase A2 receptor 1 autoantibody (PLA2R1 Ab). The adequate assessment of chimeric anti-CD20 monoclonal antibody, rituximab (RTX), efficacy is still needed to improve clinical outcome of patient with MN. We evaluated the modification of plasmablasts (CD3−CD19+CD20−IgD−CD27highCD38high), a useful biomarker of RTX response in other autoimmune diseases, and memory (CD3−CD19+CD20+IgD−CD27+CD38−) and naive (CD3−CD19+CD20+IgD+CD27−CD38low) B cells by fluorescence-activated cell sorter analysis in PLA2R1 related MN in one patient during the 4 years of follow-up after RTX. RTX induced complete disappearance of CD19+ B cells, plasmablasts, and memory B cells as soon as day 15. Despite severe CD19+ lymphopenia, plasmablasts and memory B cells reemerged early before naive B cells (days 45, 90, and 120, resp.). During the follow-up, plasmablasts decreased more rapidly than memory B cells but still remained elevated as compared to day 0 of RTX. Concomitantly, anti-PLA2R1 Ab increased progressively. Our single case report suggests that, besides monitoring of serum anti-PLA2R1 Ab level, enumeration of circulating plasmablasts and memory B cells represents an attractive and complementary tool to assess immunological activity and efficacy of RTX induced B cells depletion in anti-PLA2R1 Ab related MN. PMID:27493452

  20. Formation of complex organic molecules in cold objects: the role of gas phase reactions

    OpenAIRE

    Balucani, Nadia; Ceccarelli, Cecilia; Taquet, Vianney

    2015-01-01

    While astrochemical models are successful in reproducing many of the observed interstellar species, they have been struggling to explain the observed abundances of complex organic molecules. Current models tend to privilege grain surface over gas phase chemistry in their formation. One key assumption of those models is that radicals trapped in the grain mantles gain mobility and react on lukewarm (>30 K) dust grains. Thus, the recent detections of methyl formate (MF) and dimethyl ether (DME) ...

  1. Can arsenic-phytochelatin complex formation be used as an indicator for toxicity in Helianthus annuus?

    Science.gov (United States)

    Raab, Andrea; Ferreira, Katia; Meharg, Andrew A; Feldmann, Jörg

    2007-01-01

    The formation of arsenic-phytochelatin (As-PC) complexes is thought to be part of the plant detoxification strategy for arsenic. This work examines (i) the arsenic (As) concentration-dependent formation of As-PC complex formation and (ii) redistribution and metabolism of As after arrested As uptake in Helianthus annuus. HPLC with parallel ICP-MS/ES-MS detection was used to identify and quantify the species present in plant extracts exposed to arsenate (As(V)) (between 0 and 66.7 micromol As l-1 for 24 h). At As concentrations below the EC50 value for root growth (22 micromol As l-1) As uptake is exponential, but it is reduced at concentrations above. Translocation between root and shoot seemed to be limited to the uptake phase of arsenic. No redistribution of As between root and shoot was observed after arresting As exposure. The formation of As-PC complexes was concentration-dependent. The amount and number of As-PC complexes increased exponentially with concentration up to 13.7 micromol As l-1. As(III)-PC3 and GS-As(III)-PC2 complexes were the dominant species in all samples. The ratio of PC-bound As to unbound As increased up to 1.3 micromol As l-1 and decreased at higher concentrations. Methylation of inorganic As was only a minor pathway in H. annuus with about 1% As methylated over a 32 d period. The concentration dependence of As-PC complex formation, amount of unbound reduced and oxidized PC2, and the relative uptake rate showed that As starts to influence the cellular metabolism of H. annuus negatively at As concentrations well below the EC50 value determined by more traditional means. Generally, As-PC complexes and PC-synthesis rate seem to be the more sensitive parameters to be studied when As toxicity values are to be estimated.

  2. Thermodynamic functions of formation of n-alkane complexes with crystalline urea

    Energy Technology Data Exchange (ETDEWEB)

    Tolmachev, V.V.; Semenov, L.V.; Gaile, A.A.; Proskuryakov, V.A.

    1987-07-10

    For optimization of the conditions of deparaffination of petroleum fractions with the aid of urea, with the composition of the feedstock taken into account, it is important to know the equilibrium constants of formation of complexes of urea with n-alkanes differing in the number of carbon atoms in their molecules, as functions of temperature. In this investigation they obtained experimental data necessary for calculating the thermodynamic functions of formation of n-alkane complexes with crystalline urea up to the decomposition temperature, using Kirchhoff's equations.

  3. Complex Formation of Selected Radionuclides with Ligands Commonly Found in Ground Water: Low Molecular Organic Acids

    DEFF Research Database (Denmark)

    Jensen, Bror Skytte; Jensen, H.

    1985-01-01

    A general approach to the analysis of potentiometric data on complex formation between cations and polybasic amphoteric acids is described. The method is used for the characterisation of complex formation between Cs+, Sr2+, Co2+, La 3+, and Eu3+ with a α-hydroxy acids, tartaric acid and citric ac......, and with the α-amino acids, aspartic acid and L-cysteine. The cations have been chosen as typical components of reactor waste, and the acids because they are often found as products of microbial activity in pits or wherever organic material decays...

  4. Mass-dependent and -independent fractionation of isotopes in Ni and Pb chelate complex formation reactions

    Science.gov (United States)

    Nomura, Masao; Kudo, Takashi; Adachi, Atsuhiko; Aida, Masao; Fujii, Yasuhiko

    2013-11-01

    Mass independent fractionation (MIF) has been a very interesting topic in the field of inorganic isotope chemistry, in particular, geo- and cosmo- chemistry. In the present work, we studied the isotope fractionation of Ni(II) and Pb(II) ions in complex formation with chelating reagent EDTA. To obtain clear results on the mass dependence of the isotope fractionation, we have conducted long-distance ion exchange chromatography of Ni(II) and Pb(II), using chelate complex reagent EDTA. The results apparently show that the isotope fractionation in Ni complex formation system is governed by the mass dependent rule. On the other hand the isotope fractionation in the Pb complex system is governed by the mass independent rule or the nuclear volume effect.

  5. Mass-dependent and -independent fractionation of isotopes in Ni and Pb chelate complex formation reactions

    Energy Technology Data Exchange (ETDEWEB)

    Nomura, Masao; Kudo, Takashi; Adachi, Atsuhiko; Aida, Masao; Fujii, Yasuhiko [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, O-okayama Meguroku, Tokyo, 152-8550 (Japan)

    2013-11-13

    Mass independent fractionation (MIF) has been a very interesting topic in the field of inorganic isotope chemistry, in particular, geo- and cosmo- chemistry. In the present work, we studied the isotope fractionation of Ni(II) and Pb(II) ions in complex formation with chelating reagent EDTA. To obtain clear results on the mass dependence of the isotope fractionation, we have conducted long-distance ion exchange chromatography of Ni(II) and Pb(II), using chelate complex reagent EDTA. The results apparently show that the isotope fractionation in Ni complex formation system is governed by the mass dependent rule. On the other hand the isotope fractionation in the Pb complex system is governed by the mass independent rule or the nuclear volume effect.

  6. Thermodynamic characteristics of the formation of complexes of nickel(II) with L-homoserine

    Science.gov (United States)

    Gridchin, S. N.

    2016-12-01

    The formation of complexes of nickel(II) with L-homoserine at 298.15 K and ionic strengths I = 0.5, 1.0, and 1.5 (KNO3) are investigated by potentiometry and calorimetry. Standard characteristics of studied equilibria (log K°, Δr G°, Δr H°, and Δr S°) are determined.

  7. FORMATION AND QUANTIFICATION OF PROTEIN COMPLEXES BETWEEN PEROXISOMAL ALCOHOL OXIDASE AND GROEL

    NARCIS (Netherlands)

    EVERS, ME; LANGER, T; HARDER, W; HARTL, FU; VEENHUIS, M; Hartl, Franz-Ulrich

    1992-01-01

    We have studied the use of yeast peroxisomal alcohol oxidase (AO) as a model protein for in vitro binding by GroEL. Dilution of denatured AO in neutral buffer leads to aggregation of the protein, which is prevented by the addition of GroEL. Formation of complexes between GroEL and denatured AO was d

  8. Lymphoma Remissions Caused by Anti-CD19 Chimeric Antigen Receptor T Cells Are Associated With High Serum Interleukin-15 Levels.

    Science.gov (United States)

    Kochenderfer, James N; Somerville, Robert P T; Lu, Tangying; Shi, Victoria; Bot, Adrian; Rossi, John; Xue, Allen; Goff, Stephanie L; Yang, James C; Sherry, Richard M; Klebanoff, Christopher A; Kammula, Udai S; Sherman, Marika; Perez, Arianne; Yuan, Constance M; Feldman, Tatyana; Friedberg, Jonathan W; Roschewski, Mark J; Feldman, Steven A; McIntyre, Lori; Toomey, Mary Ann; Rosenberg, Steven A

    2017-03-14

    Purpose T cells genetically modified to express chimeric antigen receptors (CARs) targeting CD19 (CAR-19) have potent activity against acute lymphoblastic leukemia, but fewer results supporting treatment of lymphoma with CAR-19 T cells have been published. Patients with lymphoma that is chemotherapy refractory or relapsed after autologous stem-cell transplantation have a grim prognosis, and new treatments for these patients are clearly needed. Chemotherapy administered before adoptive T-cell transfer has been shown to enhance the antimalignancy activity of adoptively transferred T cells. Patients and Methods We treated 22 patients with advanced-stage lymphoma in a clinical trial of CAR-19 T cells preceded by low-dose chemotherapy. Nineteen patients had diffuse large B-cell lymphoma, two patients had follicular lymphoma, and one patient had mantle cell lymphoma. Patients received a single dose of CAR-19 T cells 2 days after a low-dose chemotherapy conditioning regimen of cyclophosphamide plus fludarabine. Results The overall remission rate was 73% with 55% complete remissions and 18% partial remissions. Eleven of 12 complete remissions are ongoing. Fifty-five percent of patients had grade 3 or 4 neurologic toxicities that completely resolved. The low-dose chemotherapy conditioning regimen depleted blood lymphocytes and increased serum interleukin-15 (IL-15). Patients who achieved a remission had a median peak blood CAR(+) cell level of 98/μL and those who did not achieve a remission had a median peak blood CAR(+) cell level of 15/μL ( P = .027). High serum IL-15 levels were associated with high peak blood CAR(+) cell levels ( P = .001) and remissions of lymphoma ( P < .001). Conclusion CAR-19 T cells preceded by low-dose chemotherapy induced remission of advanced-stage lymphoma, and high serum IL-15 levels were associated with the effectiveness of this treatment regimen. CAR-19 T cells will likely become an important treatment for patients with relapsed lymphoma.

  9. Quantum statistical vibrational entropy and enthalpy of formation of helium-vacancy complex in BCC W

    Science.gov (United States)

    Wen, Haohua; Woo, C. H.

    2016-12-01

    High-temperature advance-reactor design and operation require knowledge of in-reactor materials properties far from the thermal ground state. Temperature-dependence due to the effects of lattice vibrations is important to the understanding and formulation of atomic processes involved in irradiation-damage accumulation. In this paper, we concentrate on the formation of He-V complex. The free-energy change in this regard is derived via thermodynamic integration from the phase-space trajectories generated from MD simulations based on the quantum fluctuation-dissipation relation. The change of frequency distribution of vibration modes during the complex formation is properly accounted for, and the corresponding entropy change avoids the classical ln(T) divergence that violates the third law. The vibrational enthalpy and entropy of formation calculated this way have significant effects on the He kinetics during irradiation.

  10. Structure and kinetics of formation of catechol complexes of ferric soybean lipoxygenase-1

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, M.J.; Brennan, B.A.; Chase, D.B. [E.I. du Pont de Nemours & Co., Wilmington, DE (United States)]|[Haverford College, PA (United States)] [and others

    1995-11-21

    Ferric soybean lipoxygenase forms stable complexes with 4-substituted catechols. The structure of the complex between the enzyme and 3,4-dihydroxybenzonitrile has been studied by resonance Raman, electron paramagnetic resonance, visible, and X-ray spectroscopies. It is a bidentate iron-catecholate complex with at least one water ligand. The kinetics of formation of complexes between lipoxygenase and 3,4-dihydroxybenzonitrile and 3,4-dihydroxyacetophenone have been studied by stopped-flow spectroscopy. The data are consistent with two kinetically distinct, reversible steps. The pH dependence of the first step suggests that the substrate for the reaction is the catechol monoanion. When these results are combined, plausible mechanisms for the complexation reaction are suggested. 51 refs., 12 figs., 2 tabs.

  11. Formation of complex impact craters - Evidence from Mars and other planets

    Science.gov (United States)

    Pike, R. J.

    1980-01-01

    An analysis of the depth vs diameter data of Arthur (1980), is given along with geomorphic data for 73 Martian craters. The implications for the formation of complex impact craters on solid planets is discussed. The analysis integrates detailed morphological observations on planetary craters with geologic data from terrestrial meteorite and explosion craters. The simple to complex transition for impact craters on Mars appears at diameters in the range of 3 to 8 km. Five features appear sequentially with increasing crater size, flat floors, central peaks and shallower depths, scalloped rims, and terraced walls. This order suggests that a shallow depth of excavation and a rebound mechanism have produced the central peaks, not centripetal collapse and deep sliding. Simple craters are relatively uniform in shape from planet to planet, but complex craters vary considerably. Both the average onset diameter for complex impact craters on Mars and the average depth of complex craters vary inversely with gravitational acceleration on four planets.

  12. Formation Equilibria of Ternary Metal Complexes with Citric Acid and Glutamine (Alanine) in Aqueous Solution

    Institute of Scientific and Technical Information of China (English)

    王进平; 牛春吉; 杨魁跃; 倪嘉缵

    2004-01-01

    The species and their formation constants in the ternary systems were obtained by the Scogs2 software from potentiometric titration data. The Comics software was used to calculate the distribution of species in the ternary systems. MLXH, MLXH2 and MLXH3 are the common species in these systems. The coordination behaviors of the rare earths are very similar and their stability is closely matched. The ternary rare earth complexes are more stable than the corresponding ternary complexes of calcium. The ternary zinc complex with glutamine as the secondary ligand is more stable than the corresponding complexes of rare earths, but the ternary complex with alanine as the secondary ligand shows an inverse trend. The distributions of species in the ternary systems vary with pH changing. A prediction can be made that exogenous rare earths can affect the species of Ca and Zn in human body.

  13. The Vtc proteins in vacuole fusion: coupling NSF activity to V(0) trans-complex formation

    DEFF Research Database (Denmark)

    Müller, Oliver; Bayer, Martin J; Peters, Christopher;

    2002-01-01

    The fusion of cellular membranes comprises several steps; membrane attachment requires priming of SNAREs and tethering factors by Sec18p/NSF (N-ethylmaleimide sensitive factor) and LMA1. This leads to trans-SNARE pairing, i.e. formation of SNARE complexes between apposed membranes. The yeast...... vacuole system has revealed two subsequent molecular events: trans-complex formation of V-ATPase proteolipid sectors (V(0)) and release of LMA1 from the membrane. We have now identified a hetero-oligomeric membrane integral complex of vacuolar transporter chaperone (Vtc) proteins integrating these events....... The Vtc complex associates with the R-SNARE Nyv1p and with V(0). Subunits Vtc1p and Vtc4p control the initial steps of fusion. They are required for Sec18p/NSF activity in SNARE priming, membrane binding of LMA1 and V(0) trans-complex formation. In contrast, subunit Vtc3p is required for the latest step...

  14. HCF-1 self-association via an interdigitated Fn3 structure facilitates transcriptional regulatory complex formation.

    Science.gov (United States)

    Park, Jihye; Lammers, Fabienne; Herr, Winship; Song, Ji-Joon

    2012-10-23

    Host-cell factor 1 (HCF-1) is an unusual transcriptional regulator that undergoes a process of proteolytic maturation to generate N- (HCF-1(N)) and C- (HCF-1(C)) terminal subunits noncovalently associated via self-association sequence elements. Here, we present the crystal structure of the self-association sequence 1 (SAS1) including the adjacent C-terminal HCF-1 nuclear localization signal (NLS). SAS1 elements from each of the HCF-1(N) and HCF-1(C) subunits form an interdigitated fibronectin type 3 (Fn3) tandem repeat structure. We show that the C-terminal NLS recruited by the interdigitated SAS1 structure is required for effective formation of a transcriptional regulatory complex: the herpes simplex virus VP16-induced complex. Thus, HCF-1(N)-HCF-1(C) association via an integrated Fn3 structure permits an NLS to facilitate formation of a transcriptional regulatory complex.

  15. Stability of furosemide polymorphs and the effects of complex formation with β-cyclodextrin and maltodextrin.

    Science.gov (United States)

    Garnero, Claudia; Chattah, Ana Karina; Longhi, Marcela

    2016-11-05

    The effect of the formation of supramolecular binary complexes with β-cyclodextrin and maltodextrin on the chemical and physical stability of the polymorphs I and II of furosemide was evaluated in solid state. The solid samples were placed under accelerated storage conditions and exposed to daylight into a stability chamber for a 6-month. Chemical stability was monitored by high performance liquid chromatography, while the physical stability was studied by solid state nuclear magnetic resonance, powder X-ray diffraction and scanning electron microscopy. Changes in the physical appearance of the samples were evaluated. The studies showed a significant stabilizing effect of β-cyclodextrin on furosemide form II. Our results suggest that the complex formation is a useful tool for improving the stability of furosemide polymorphs. These new complexes are promising candidates that can be used in the pharmaceutical industry for the preparation of alternative matrices that improve physicochemical properties.

  16. Lethal synergism between organic and inorganic wood preservatives via formation of an unusual lipophilic ternary complex

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, Zhi-Guo; Li, Yan; Fan, Rui-Mei; Chao, Xi-Juan [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085 (China); Zhu, Ben-Zhan, E-mail: bzhu@rcees.ac.cn [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085 (China); Linus Pauling Institute, Oregon State University, Corvallis, OR 97331 (United States)

    2013-02-01

    We have shown previously that exposing bacteria to wood preservatives pentachlorophenol (PCP) and copper-containing compounds together causes synergistic toxicity. However, it is not clear whether these findings also hold true in mammalian cells; and if so, what is the underlying molecular mechanism? Here we show that PCP and a model copper complex bis-(1,10-phenanthroline) cupric (Cu(OP){sub 2}), could also induce synergistic cytotoxicity in human liver cells. By the single crystal X-ray diffraction and atomic absorption spectroscopy assay, the synergism was found to be mainly due to the formation of a lipophilic ternary complex with unusual structural and composition characteristics and subsequent enhanced cellular copper uptake, which markedly promoted cellular reactive oxygen species (ROS) production, leading to apoptosis by decreasing mitochondrial membrane potential, increasing pro-apoptotic protein expression, releasing cytochrome c from mitochondria and activating caspase-3, and -9. Analogous results were observed with other polychlorinated phenols (PCPs) and Cu(OP){sub 2}. Synergistic cytotoxicity could be induced by PCP/Cu(OP){sub 2} via formation of an unusual lipophilic complex in HepG2 cells. The formation of ternary complexes with similar lipophilic character could be of relevance as a general mechanism of toxicity, which should be taken into consideration especially when evaluating the toxicity of environmental pollutants found at currently-considered non- or sub-toxic concentrations. -- Highlights: ► The combination of PCP/Cu(OP){sub 2} induces synergistic cytotoxicity in HepG2 cells. ► The synergism is mainly due to forming a lipophilic ternary complex between them. ► The formation of lipophilic ternary complex enhances cellular copper uptake. ► PCP/Cu(OP){sub 2} stimulates the cellular ROS production. ► The ROS promoted by PCP/Cu(OP){sub 2} induces mitochondria-dependent apoptosis.

  17. Complexes of triggered star formation in supergiant shell of Holmberg II

    Science.gov (United States)

    Egorov, Oleg V.; Lozinskaya, Tatiana A.; Moiseev, Alexei V.; Shchekinov, Yuri A.

    2017-01-01

    We report a detailed analysis of all regions of current star formation in the walls of the supergiant H I shell (SGS) in the galaxy Holmberg II based on observations with a scanning Fabry-Perot interferometer at the Russian 6-m telescope. We compare the structure and kinematics of ionized gas with that of atomic hydrogen and with the stellar population of the SGS. Our deep Hα images and archival images taken by the Hubble Space Telescope demonstrate that current star formation episodes are larger and more complicated than previously thought: they represent unified star-forming complexes with sizes of several hundred pc rather than `chains' of separate bright nebulae in the walls of the SGS. The fact that we are dealing with unified complexes is evidenced by identified faint shell-like structures of ionized and neutral gas which connect several distinct bright H II regions. Formation of such complexes is due to the feedback of stars with very inhomogeneous ambient gas in the walls of the SGS. The arguments supporting an idea about the triggering of star formation in SGS by the H I supershells collision are presented. We also found a faint ionized supershell inside the H I SGS expanding with a velocity of no greater than 10-15 km s-1. Five OB stars located inside the inner supershell are sufficient to account for its radiation, although a possibility of leakage of ionizing photons from bright H II regions is not ruled out as well.

  18. Toward a Reduced Complexity Channel Resolving Model for Sedimentary Delta Formation

    Science.gov (United States)

    Liang, M.; Voller, V. R.; Edmonds, D. A.; Paola, C.

    2010-12-01

    Predicting styles of delta growth in restoration areas is a challenge as we try to restore impacted coastlines. Cellular and rule-based reduced complexity models offer a worthwhile means of uncovering key dynamics in delta morphodynamics without the need to fully solve the governing transport equations. In terms of modeling sedimentary delta building processes a critical ingredients is accounting for the formation and bifurcation of channels; phenomena that can be related to the formation of levees and mouth-bars. To that end, we have developed a reduced complexity model that uses a simplified shallow-water solver to study channel formation, mouth bar deposition, and delta development under different forcings. Under the assumption that the flow has a very low Froude Number (Fr2jet. We test the reduced model against flow over Gaussian-shaped bumps of various heights. Comparison of results from this model with results from a full scale commercial code (Delft3D) show a satisfactory agreement on the critical mouth bar height needed to divert flow around the bar. Based on the same diffusive equation, we develop a low-Froude water-routing method for reduced complexity morphodynamics models. The preliminary results show that the method is capable of producing reasonable channel forms and mouth bar formation, and provides a good starting point for development of a channel resolving delta building model.

  19. Complexes of triggered star formation in supergiant shell of Holmberg II.

    Science.gov (United States)

    Egorov, Oleg V.; Lozinskaya, Tatiana A.; Moiseev, Alexei V.; Shchekinov, Yuri A.

    2016-09-01

    We report a detailed analysis of all regions of current star formation in the walls of the supergiant H I shell (SGS) in the galaxy Holmberg II based on observations with a scanning Fabry-Perot interferometer at the 6-m SAO RAS telescope. We compare the structure and kinematics of ionized gas with that of atomic hydrogen and with the stellar population of the SGS. Our deep Hα images and archival images taken by the HST demonstrate that current star formation episodes are larger and more complicated than previously thought: they represent unified star-forming complexes with sizes of several hundred pc rather than `chains' of separate bright nebulae in the walls of the SGS. The fact that we are dealing with unified complexes is evidenced by identified faint shell-like structures of ionized and neutral gas which connect several distinct bright H II regions. Formation of such complexes is due to the feedback of stars with very inhomogeneous ambient gas in the walls of the SGS. The arguments supporting an idea about the triggering of star formation in SGS by the H I supershells collision are presented. We also found a faint ionized supershell inside the H I SGS expanding with a velocity of no greater than 10 - 15 km s-1. Five OB stars located inside the inner supershell are sufficient to account for its radiation, although a possibility of leakage of ionizing photons from bright H II regions is not ruled out as well.

  20. Ubisemiquinone is the electron donor for superoxide formation by complex III of heart mitochondria.

    Science.gov (United States)

    Turrens, J F; Alexandre, A; Lehninger, A L

    1985-03-01

    Much evidence indicates that superoxide is generated from O2 in a cyanide-sensitive reaction involving a reduced component of complex III of the mitochondrial respiratory chain, particularly when antimycin A is present. Although it is generally believed that ubisemiquinone is the electron donor to O2, little experimental evidence supporting this view has been reported. Experiments with succinate as electron donor in the presence of antimycin A in intact rat heart mitochondria, which contain much superoxide dismutase but little catalase, showed that myxothiazol, which inhibits reduction of the Rieske iron-sulfur center, prevented formation of hydrogen peroxide, determined spectrophotometrically as the H2O2-peroxidase complex. Similarly, depletion of the mitochondria of their cytochrome c also inhibited formation of H2O2, which was restored by addition of cytochrome c. These observations indicate that factors preventing the formation of ubisemiquinone also prevent H2O2 formation. They also exclude ubiquinol, which remains reduced under these conditions, as the reductant of O2. Since cytochrome b also remains fully reduced when myxothiazol is added to succinate- and antimycin A-supplemented mitochondria, reduced cytochrome b may also be excluded as the reductant of O2. These observations, which are consistent with the Q-cycle reactions, by exclusion of other possibilities leave ubisemiquinone as the only reduced electron carrier in complex III capable of reducing O2 to O2-.

  1. The role of focal adhesion complexes in fibroblast mechanotransduction during scar formation.

    Science.gov (United States)

    Rustad, Kristine C; Wong, Victor W; Gurtner, Geoffrey C

    2013-10-01

    Historically, great efforts have been made to elucidate the biochemical pathways that direct the complex process of wound healing; however only recently has there been recognition of the importance that mechanical signals play in the process of tissue repair and scar formation. The body's physiologic response to injury involves a dynamic interplay between mechanical forces and biochemical cues which directs a cascade of signals leading ultimately to the formation of fibrotic scar. Fibroblasts are a highly mechanosensitive cell type and are also largely responsible for the generation of the fibrotic matrix during scar formation and are thus a critical player in the process of mechanotransduction during tissue repair. Mechanotransduction is initiated at the interface between the cell membrane and the extracellular matrix where mechanical signals are first translated into a biochemical response. Focal adhesions are dynamic multi-protein complexes through which the extracellular matrix links to the intracellular cytoskeleton. These focal adhesion complexes play an integral role in the propagation of this initial mechanical cue into an extensive network of biochemical signals leading to widespread downstream effects including the influx of inflammatory cells, stimulation of angiogenesis, keratinocyte migration, fibroblast proliferation and collagen synthesis. Increasing evidence has demonstrated the importance of the biomechanical milieu in healing wounds and suggests that an integrated approach to the discovery of targets to decrease scar formation may prove more clinically efficacious than previous purely biochemical strategies.

  2. The influence of amylose-LPC complex formation on the susceptibility of wheat starch to amylase.

    Science.gov (United States)

    Ahmadi-Abhari, S; Woortman, A J J; Oudhuis, A A C M; Hamer, R J; Loos, K

    2013-09-12

    This study was aimed to assess the role of lysophosphatidylcholine (LPC) in the development of slowly digestible starch (SDS). The influence of LPC, on the enzymatic degradation of diluted 9% wheat starch suspensions (w/w) was investigated, using an in vitro digestion method. Wheat starch suspensions containing 0.5-5% LPC (based on starch) were heated in a Rapid Visco Analyser (RVA) till 95 °C and subjected to enzyme hydrolysis by porcine pancreatic α-amylase at 37 °C for several digestion periods. In vitro digestion measurements demonstrated that complexing starch with 5% LPC leads to a 22% decrease in rate of reducing sugar compared to the reference while the samples containing 0.5% LPC showed an equal digestibility comparable to the control. A clear decrease in the formation of reducing sugars was observed in presence of 2-5% LPC, since the results after 15 min digestion imply the formation of SDS due to the formation of amylose-LPC inclusion complexes. The DSC measurements proved the presence of amylose-LPC inclusion complexes even after 240 min digestion demonstrating the low susceptibility of amylose-V complexes to amylase.

  3. A study of the formation constants of ternary and quaternary complexes of some bivalent transition metals

    Directory of Open Access Journals (Sweden)

    MADHURJYA NEOG

    2010-01-01

    Full Text Available The formation of hetero-ligand 1:1:1, M(II-Opda-Sal/Gly ternary and 1:1:1:1, M(II-Opda-Sal-Gly quaternary complexes, where M(II = Ni, Cu, Zn and Cd; Opda = o‑phenylenediamine, Sal = salicylic acid, Gly = glycine, was studied pH-metrically in aqueous medium. The formation constants for the resulting ternary and quaternary complexes were evaluated at a constant ionic strength, μ = 0.20 mol dm-3 and temperature, 30±0.1 °C. The order of the formation constants in terms of the metal ion for both type of complexes was found to be Cu(II > Ni(II > Zn(II > Cd(II. This order was explained based on the increasing number of fused rings, the coordination number of the metal ions, the Irving – William order and the stability of various species. The expected species formed in solution were pruned with the Fortran IV program SPEPLOT and the stability of the ternary and quaternary complexes is explained.

  4. Speciation of phytate ion in aqueous solution. Alkali metal complex formation in different ionic media.

    Science.gov (United States)

    De Stefano, Concetta; Milea, Demetrio; Pettignano, Alberto; Sammartano, Silvio

    2003-08-01

    The acid-base properties of phytic acid [ myo-inositol 1,2,3,4,5,6-hexakis(dihydrogen phosphate)] (H(12)Phy; Phy(12-)=phytate anion) were studied in aqueous solution by potentiometric measurements ([H+]-glass electrode) in lithium and potassium chloride aqueous media at different ionic strengths (0iodide (Et(4)NI; e.g., at I=0.5 mol L(-1), log K(3)(H)=11.7, 8.0, 9.1, and 9.1 in Et(4)NI, LiCl, NaCl and KCl, respectively; the protonation constants in Et(4)NI and NaCl were already reported), owing to the strong interactions occurring between the phytate and alkaline cations present in the background salt. We explained this in terms of complex formation between phytate and alkali metal ions. Experimental evidence allows us to consider the formation of 13 mixed proton-metal-ligand complexes, M(j)H(i)Phy((12-i-j)-), (M+ =Li+, Na+, K+), with jstability of alkali metal complexes follows the trend Li+ > or =Na+K+. Some measurements were also performed at constant ionic strength (I=0.5 mol L(-1)), using different mixtures of Et(4)NI and alkali metal chlorides, in order to confirm the formation of hypothesized and calculated metal-proton-ligand complex species and to obtain conditional protonation constants in these multi-component ionic media.

  5. Globular cluster formation with multiple stellar populations from hierarchical star cluster complexes

    Science.gov (United States)

    Bekki, Kenji

    2017-01-01

    Most old globular clusters (GCs) in the Galaxy are observed to have internal chemical abundance spreads in light elements. We discuss a new GC formation scenario based on hierarchical star formation within fractal molecular clouds. In the new scenario, a cluster of bound and unbound star clusters (`star cluster complex', SCC) that have a power-law cluster mass function with a slope (β) of 2 is first formed from a massive gas clump developed in a dwarf galaxy. Such cluster complexes and β = 2 are observed and expected from hierarchical star formation. The most massive star cluster (`main cluster'), which is the progenitor of a GC, can accrete gas ejected from asymptotic giant branch (AGB) stars initially in the cluster and other low-mass clusters before the clusters are tidally stripped or destroyed to become field stars in the dwarf. The SCC is initially embedded in a giant gas hole created by numerous supernovae of the SCC so that cold gas outside the hole can be accreted onto the main cluster later. New stars formed from the accreted gas have chemical abundances that are different from those of the original SCC. Using hydrodynamical simulations of GC formation based on this scenario, we show that the main cluster with the initial mass as large as [2 - 5] × 105M⊙ can accrete more than 105M⊙ gas from AGB stars of the SCC. We suggest that merging of hierarchical star cluster complexes can play key roles in stellar halo formation around GCs and self-enrichment processes in the early phase of GC formation.

  6. A Reaction Method for Estimating Gibbs Energy and Enthalpy of Formation of Complex Minerals

    Science.gov (United States)

    Li, Ruibing; Zhang, Tingan; Liu, Yan; Kuang, Shibo

    2017-04-01

    New and updated thermodynamic data for simple binary compounds are readily available from both experimental measurements and theoretical calculations. Based on these available data, an approach is proposed to predict Gibbs energies and enthalpies of formation for complex minerals of metallurgical, chemical, and other industrial importance. The approach assumes that complex minerals are formed from binary composite oxides, which in turn, are formed from individual pure oxides. The validity of this approach is examined by comparing the calculated values of Gibbs energies and enthalpies against the experimentally measured ones reported in literature. The results show that for typical complex minerals with available experimental data, the calculated results exhibit an average residual of 0.51 pct for Gibbs energies and 0.52 pct for enthalpies, compared to the experimental results. This new approach thus correlates well with experimental approaches and can be applied to most of the complex minerals.

  7. Reversible Formation and Transmetalation of Schiff-Base Complexes in Subcomponent Self-Assembly Reactions.

    Science.gov (United States)

    Lewing, Dennis; Koppetz, Hannah; Hahn, F Ekkehardt

    2015-08-03

    Dinuclear complexes [Zn2(NS,NS)2] 3 and [Ni2(NS,NS)2] 6 bearing Schiff-base ligands featuring two NS donor groups were obtained in subcomponent self-assembly reactions using nickel or zinc as template metals. Several transmetalation reactions starting from 3 or 6 yielded the complexes [Pd2(NS,NS)2] 4 and [Co2(NS,NS)2] 5, and their molecular structures were determined by X-ray diffraction. Starting from the mononuclear complex [Ni(NS/NOH)2] 9 featuring a coordinated NS Schiff base and a free NOH Schiff base, completely reversible thermodynamically controlled imine bond formation was observed leading to complex [Ni2(NS,NS)2] 6 and the free Schiff -base ligand NOH,NOH 10.

  8. Higher proportions of peripheral CD19+CD5+ B cells predict the effect of corticosteroid in patients with late-onset hemorrhagic cystitis after allogeneic hematopoietic stem cell transplantation

    Institute of Scientific and Technical Information of China (English)

    FU Hai-xia; WANG Jing-zhi; ZHAO Ting; ZHANG Yuan-yuan; CHEN Yao; HUANG Xiao-jun; XU Lan-ping; LIU Dai-hong; LIU Kai-yan; CHEN Huan; HAN Wei; ZHANG Xiao-hui; WANG Yu; WANG Feng-rong

    2011-01-01

    Background The cause of late-onset hemorrhagic cystitis (LOHC) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains obscure. In clinical practice, some LOHC patients respond to immunosuppression.The aim of this study was to determine the immune pathogenesis of LOHC post allo-HSCT.Methods With the diagnosis of LOHC, patients were given initial treatment consisting of fluid hydration, alkalization and forced diuresis, and empirical anti-viral therapy for 10-14 days or until a week after the virus became negative. The nonresponders were applied corticosteroid. Seven to ten days later, patients' response was evaluated. Along with treatment, CD19+ B lymphocyte subsets were measured at various study points.Results From October 2009 to March 2010, we found 28 cases of LOHC occurred in 25 patients who underwent allo-HSCT in our hospital. Except that three cases were not treated according to the protocol, the other 25 cases were divided into three groups: anti-virus responders (Group A, n=6), corticosteroid responders (Group B1, n=16),corticosteroid and anti-virus nonresponders (Group C, n=3) according to their clinical response. Percentages of CD19+CD5+ B lymphocytes were not significantly different among three groups at onset of LOCH. However, in Group B1after the first anti-virus phase, percentages of CD19+CD5+ lymphocytes significantly increased comparing with those at onset (P=0.022), and then significantly decreased at PR (P=0.003) and CR (P=0.002) with corticosteroid treatment. But significant change was not observed in Groups A and C.Conclusion The immune etiology seems to be involved in the development of LOHC and the proportion of CD19+CD5+lymphocytes may serve as a cellular biomarker to predict the response to corticosteroid in LOHC.

  9. An autocatalytic radical chain pathway in formation of an iron(IV)-oxo complex by oxidation of an iron(II) complex with dioxygen and isopropanol.

    Science.gov (United States)

    Morimoto, Yuma; Lee, Yong-Min; Nam, Wonwoo; Fukuzumi, Shunichi

    2013-03-28

    Evidence of an autocatalytic radical chain pathway has been reported in formation of a non-heme iron(IV)-oxo complex by oxidation of an iron(II) complex with dioxygen and isopropanol in acetonitrile at 298 K. The radical chain reaction is initiated by hydrogen abstraction from isopropanol by the iron(IV)-oxo complex.

  10. Rapid-reaction kinetic characterization of the pathway of streptokinase-plasmin catalytic complex formation.

    Science.gov (United States)

    Verhamme, Ingrid M; Bock, Paul E

    2008-09-19

    Binding of the fibrinolytic proteinase plasmin (Pm) to streptokinase (SK) in a tight stoichiometric complex transforms Pm into a potent proteolytic activator of plasminogen. SK binding to the catalytic domain of Pm, with a dissociation constant of 12 pm, is assisted by SK Lys(414) binding to a Pm kringle, which accounts for a 11-20-fold affinity decrease when Pm lysine binding sites are blocked by 6-aminohexanoic acid (6-AHA) or benzamidine. The pathway of SK.Pm catalytic complex formation was characterized by stopped-flow kinetics of SK and the Lys(414) deletion mutant (SKDeltaK414) binding to Pm labeled at the active site with 5-fluorescein ([5F]FFR-Pm) and the reverse reactions by competitive displacement of [5F]FFR-Pm with active site-blocked Pm. The rate constants for the biexponential fluorescence quenching caused by SK and SKDeltaK414 binding to [5F]FFR-Pm were saturable as a function of SK concentration, reporting encounter complex affinities of 62-110 nm in the absence of lysine analogs and 4900-6500 and 1430-2200 nm in the presence of 6-AHA and benzamidine, respectively. The encounter complex with SKDeltaK414 was approximately 10-fold weaker in the absence of lysine analogs but indistinguishable from that of native SK in the presence of 6-AHA and benzamidine. The studies delineate for the first time the sequence of molecular events in the formation of the SK.Pm catalytic complex and its regulation by kringle ligands. Analysis of the forward and reverse reactions supports a binding mechanism in which SK Lys(414) binding to a Pm kringle accompanies near-diffusion-limited encounter complex formation followed by two slower, tightening conformational changes.

  11. cAMP prevents TNF-induced apoptosis through inhibiting DISC complex formation in rat hepatocytes.

    Science.gov (United States)

    Bhattacharjee, Rajesh; Xiang, Wenpei; Wang, Yinna; Zhang, Xiaoying; Billiar, Timothy R

    2012-06-22

    Tumor necrosis factor α (TNF) is a pleiotropic proinflammatory cytokine that plays a role in immunity and the control of cell proliferation, cell differentiation, and apoptosis. The pleiotropic nature of TNF is due to the formation of different signaling complexes upon the binding of TNF to its receptor, TNF receptor type 1 (TNFR1). TNF induces apoptosis in various mammalian cells when the cells are co-treated with a transcription inhibitor like actinomycin D (ActD). When TNFR1 is activated, it recruits an adaptor protein, TNF receptor-associated protein with death domain (TRADD), through its cytoplasmic death effector domain (DED). TRADD, in turn, recruits other signaling proteins, including TNF receptor-associated protein 2 (TRAF2) and receptor-associated protein kinase (RIPK) 1, to form a complex. Subsequently, this complex combines with FADD and procaspase-8, converts into a death-inducing signaling complex (DISC) to induce apoptosis. Cyclic AMP (cAMP) is a second messenger that regulates various cellular processes such as cell proliferation, gene expression, and apoptosis. cAMP analogues are reported to act as anti-apoptotic agents in various cell types, including hepatocytes. We found that a cAMP analogue, dibutyryl cAMP (db-cAMP), inhibits TNF+ActD-induced apoptosis in rat hepatocytes. The protein kinase A (PKA) inhibitor KT-5720 reverses this inhibitory effect of cAMP on apoptosis. Cytoprotection by cAMP involves down-regulation of various apoptotic signal regulators like TRADD and FADD and inhibition of caspase-8 and caspase-3 cleavage. We also found that cAMP exerts its affect at the proximal level of TNF signaling by inhibiting the formation of the DISC complex upon the binding of TNF to TNFR1. In conclusion, our study shows that cAMP prevents TNF+ActD-induced apoptosis in rat hepatocytes by inhibiting DISC complex formation.

  12. Spectroscopic studies on U(VI)-salicylate complex formation with multiple equilibria

    Energy Technology Data Exchange (ETDEWEB)

    Cha, W.; Cho, H.R.; Jung, E.C.; Park, K.K.; Kim, W.H.; Song, K. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of). Nuclear Chemistry Research Div.

    2012-07-01

    This study investigates multiple equilibria related to the formation of the U(VI)-salicylate complex in a pH range of 3.0-5.5 using UV-Vis absorption and fluorescence measurement techniques. The absorbance changes at the characteristic charge-transfer bands of the complex were monitored, and the results indicated the presence of multiple equilibria and the formation of both 1:1 and 1:2 (U(VI):salicylate) complexes possessing bi-dentate chelate structures. The determined step-wise formation constants (log K{sub 1:1} and log K{sub 1:2}) are as follows: 12.5 {+-} 0.1 and 11.4 {+-} 0.2 for salicylate, 11.2 {+-} 0.1 and 10.1 {+-} 0.2 for 5-sulfosalicylate, and 12.4 {+-} 0.1 and 11.4 {+-} 0.1 for 2,6-dihydroxybenzoate, respectively. The molar absorptivities of the complexes are also provided. Furthermore, time-resolved laser-induced luminescence spectra of U(VI) species demonstrate the presence of both a dynamic and static quenching process upon the addition of a salicylate ligand. Particularly for the luminescent hydroxouranyl species, a strong static quenching effect is observed. The results suggest that both the UO{sub 2}(HSal){sup +} and the U(VI)-Sal chelate complexes serve as ground-state complexes that induce static quenching. The Stern-Volmer parameters were derived based on the measured luminescent intensity and lifetime data. The static quenching constants (log K{sub S}) obtained are 3.3 {+-} 0.1, 4.9 {+-} 0.1, and 4.4 {+-} 0.1 for UO{sub 2}{sup 2+}, (UO{sub 2}){sub 2}(OH){sub 2}{sup 2+} and (UO{sub 2}){sub 3}(OH){sub 5}{sup +}, respectively. (orig.)

  13. Thermodynamics of mixed-ligand complex formation of mercury (II) ethylenediaminetetraacetate with amino acids in solution

    Energy Technology Data Exchange (ETDEWEB)

    Pyreu, Dmitrii, E-mail: pyreu@mail.ru [Department of Inorganic and Analytic Chemistry, Ivanovo State University, Ermak 39, Ivanovo 153025 (Russian Federation); Kozlovskii, Eugenii [Department of Inorganic and Analytic Chemistry, Ivanovo State University, Ermak 39, Ivanovo 153025 (Russian Federation); Gruzdev, Matvei; Kumeev, Roman [Institute of Solution Chemistry, Ivanovo (Russian Federation)

    2012-11-20

    Highlights: Black-Right-Pointing-Pointer Stable mixed ligand complexes of HgEdta with amino acids at physiological pH value. Black-Right-Pointing-Pointer The thermodynamic and NMR data evident the ambidentate coordination mode of arginine. Black-Right-Pointing-Pointer Participation of the guanidinic group of Arg in coordination process. Black-Right-Pointing-Pointer Binuclear complexes (HgEdta){sub 2}L with the bridging function of amino acid. - Abstract: The mixed-ligand complex formation in the systems Hg{sup 2+} - Edta{sup 4-} - L{sup -}(L = Arg, Orn, Ser) has been studied by means of calorimetry, pH-potentiometry and NMR spectroscopy in aqueous solution at 298.15 K and the ionic strength of I = 0.5 (KNO{sub 3}). The thermodynamic parameters of formation of the HgEdtaL, HgEdtaHL and (HgEdta){sub 2}L complexes have been determined. The most probable coordination mode for the complexone and the amino acid in the mixed-ligand complexes was discussed.

  14. 3D structure and formation of hydrothermal vent complexes in the Møre Basin

    Science.gov (United States)

    Kjoberg, Sigurd; Schmiedel, Tobias; Planke, Sverre; Svensen, Henrik H.; Galland, Oliver; Jerram, Dougal A.

    2016-04-01

    The mid-Norwegian Møre margin is regarded as a type example of a volcanic rifted margin, with its formation usually related to the influence of the Icelandic plume activity. The area is characterized by the presence of voluminous basaltic complexes such as extrusive lava sequences, intrusive sills and dikes, and hydrothermal vent complexes within the Møre Basin. Emplacement of hydrothermal vent complexes is accommodated by deformation of the host rock. The edges of igneous intrusions mobilize fluids by heat transfer into the sedimentary host rock (aureoles). Fluid expansion may lead to formation of piercing structures due to upward fluid migration. Hydrothermal vent complexes induce bending of overlying strata, leading to the formation of dome structures at the paleo-surface. These dome structures are important as they indicate the accommodation created for the intrusions by deformation of the upper layers of the stratigraphy, and may form important structures in many volcanic margins. Both the morphological characteristics of the upper part and the underlying feeder-structure (conduit-zone) can be imaged and studied on 3D seismic data. Seismic data from the Tulipan prospect located in the western part of the Møre Basin have been used in this study. The investigation focusses on (1) the vent complex geometries, (2) the induced surface deformation patterns, (3) the relation to the intrusions (heat source), as well as (4) the emplacement depth of the hydrothermal vent complexes. We approach this by doing a detailed 3D seismic interpretation of the Tulipan seismic data cube. The complexes formed during the initial Eocene, and are believed to be a key factor behind the rapid warming event called the Paleocene-Eocene thermal maximum (PETM). The newly derived understanding of age, eruptive deposits, and formation of hydrothermal vent complexes in the Møre Basin enables us to contribute to the general understanding of the igneous plumbing system in volcanic basins and

  15. High-Frequency Promoter Firing Links THO Complex Function to Heavy Chromatin Formation

    DEFF Research Database (Denmark)

    Mouaikel, John; Causse, Sébastien Z; Rougemaille, Mathieu;

    2013-01-01

    The THO complex is involved in transcription, genome stability, and messenger ribonucleoprotein (mRNP) formation, but its precise molecular function remains enigmatic. Under heat shock conditions, THO mutants accumulate large protein-DNA complexes that alter the chromatin density of target genes...... (heavy chromatin), defining a specific biochemical facet of THO function and a powerful tool of analysis. Here, we show that heavy chromatin distribution is dictated by gene boundaries and that the gene promoter is necessary and sufficient to convey THO sensitivity in these conditions. Single...

  16. Standard Enthalpies of Formation of Solid Complexes of Lanthanide Nitrates with Alanine

    Institute of Scientific and Technical Information of China (English)

    杨旭武; 陈三平; 高胜利; 刘晓华; 史启祯

    2002-01-01

    The combustion energies of fourteen solid complexes of lanthanide nitrate with alanine were determined. The standard enthalpies of combustion, Δc,coor(s)H°, and standard enthalpies of formation, Δf,coor(s)H°, were calculated for these complexes. The relationship of Δc,coor(s)H° and Δf,coor(s)H° with the atomic numbers of the elements in the lanthanide series were examined. The results show that a certain amount of covalence is present in the chemical bond between the lanthanide cations and alanine.

  17. EPR study of complex formation between copper (II) ions and sympathomimetic amines in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Preoteasa, E.A. [Inst. of Atomic Physics, IFIN, Bucharest (Romania); Duliu, O.G.; Grecu, V.V. [Bucharest, Univ. (Romania). Dept. of Atomic and Nuclear Physics

    1997-07-01

    The complex formation between sympathomimetic amines (SA): adrenaline (AD), noradrenaline (NA), dopamine (DA), ephedrine (ED) and p-tyramine (pTA), and Cu(II) ion in aqueous solution has been studied by X-band EPR at room temperature. Excepting pTA, all investigated SA yielded two types of complexes in different pH domains. All complexes consistent with a ligand fields having a distorted octahedral symmetry, i.e., hexacoordination of Cu(II). The covalence coefficient calculated from the isotropic g and A values has shown strong ionic sigma-type ligand bonds. A structural model with the Cu(II) ion bound by four catecholic O(hydroxy) atoms for the low pH complexes of AD, NA and DA is proposed. For the high pH complexes of the former compounds as well as for both Ed complexes, the authors suppose Cu(II) bound by two N (amino) and two O (hydroxy) atoms. The spectra are consistent to water binding on the longitudinal octahedron axis in all compounds excepting the high pH complex of Ed, where OH2- ions are bound. Possible implications for the SA-cell receptors interactions are discussed.

  18. Green synthesis of ZnO nanoparticles via complex formation by using Curcuma longa extract

    Energy Technology Data Exchange (ETDEWEB)

    Fatimah, Is, E-mail: isfatimah@uii.ac.id; Yudha, Septian P.; Mutiara, Nur Afisa Lintang [Chemistry Department, Islamic University of Indonesia Kampus Terpadu UII, Jl. Kaliurang Km 14, Sleman, Yogyakarta (Indonesia)

    2016-02-08

    Synthesis of ZnO nanoparticles(NPs) were conducted via Zn(II) complex formation by using Curcuma longa extract as template. Curcuma longa extract has the ability to form zinc ions complex with curcumin as ligating agent. Study on synthesis was conducted by monitoring thermal degradation of the material. Successful formation of zinc oxide nanoparticles was confirmed by employing x-ray diffraction, surface area analysis and transmission electron microscopy(TEM) studies. From the XRD analysis it is denoted that ZnO in hexagonal wurtzite phase was formed and particle size was varied as varied temperature. The data are also confirmed by TEM analysis which shows the particle sie at the range 20-80nm. The NPs exhibited excelent photocatalytic activity for methylene blue degradation and also significant antibacterial activity for Eschericia coli. The activity in methylene blue degradation was also confirmed from fast chemical oxygen demand (COD) reduction.

  19. Pattern formation in a complex Swift-Hohenberg equation with phase bistability

    CERN Document Server

    de Valcárcel, Manuel Martínez-Quesada Germán J

    2016-01-01

    We study pattern formation in a complex Swift Hohenberg equation with phase-sensitive (parametric) gain. Such an equation serves as a universal order parameter equation describing the onset of spontaneous oscillations in extended systems submitted to a kind of forcing dubbed rocking when the instability is towards long wavelengths. Applications include two-level lasers and photorefractive oscillators. Under rocking, the original continuous phase symmetry of the system is replaced by a discrete one, so that phase bistability emerges. This leads to the spontaneous formation of phase-locked spatial structures like phase domains and dark-ring (phase-) cavity solitons. Stability of the homogeneous solutions is studied and numerical simulations are made covering all the dynamical regimes of the model, which turn out to be very rich. Formal derivations of the rocked complex Swift-Hohenberg equation, using multiple scale techniques, are given for the two-level laser and the photorefractive oscillator.

  20. Green synthesis of ZnO nanoparticles via complex formation by using Curcuma longa extract

    Science.gov (United States)

    Fatimah, Is; Yudha, Septian P.; Mutiara, Nur Afisa Lintang

    2016-02-01

    Synthesis of ZnO nanoparticles(NPs) were conducted via Zn(II) complex formation by using Curcuma longa extract as template. Curcuma longa extract has the ability to form zinc ions complex with curcumin as ligating agent. Study on synthesis was conducted by monitoring thermal degradation of the material. Successful formation of zinc oxide nanoparticles was confirmed by employing x-ray diffraction, surface area analysis and transmission electron microscopy(TEM) studies. From the XRD analysis it is denoted that ZnO in hexagonal wurtzite phase was formed and particle size was varied as varied temperature. The data are also confirmed by TEM analysis which shows the particle sie at the range 20-80nm. The NPs exhibited excelent photocatalytic activity for methylene blue degradation and also significant antibacterial activity for Eschericia coli. The activity in methylene blue degradation was also confirmed from fast chemical oxygen demand (COD) reduction.

  1. Adsorption of Thiourea and Formation of Nickel-thiourea Complexes at Initial Stage of Nickel Deposition

    Institute of Scientific and Technical Information of China (English)

    HU Guang-hui; WU Hui-huang; YANG Fang-zu; LIU Xin-yu

    2004-01-01

    The effect of thiourea(TU) on the nickel deposition process was analyzed by means of linear-sweep voltammetry. Raman spectroscopy and infrared reflectance spectroscopy were used to investigate the adsorption of TU and the formation of nickel-TU complexes on copper surface. The experimental results indicate that the nucleation and the preceding conversion step are involved in the deposition of nickel on copper electrodes. TU makes the onset nucleation potential negative due to the formation of nickel-TU complexes, which can accelerate the nickel deposition. Moreover, the S atom in the TU molecule adsorbed on copper surface facilitates the coordination of TU to Ni2+. Meanwhile, TU might be adsorbed at a flatter orientation if no Ni2+ is on the surface, while at a perpendicular orientation when Ni2+ is coadsorbed.

  2. Decay of Activity Complexes, Formation of Unipolar Magnetic Regions and Coronal Holes in their Causal Relation

    CERN Document Server

    Golubeva, Elena

    2016-01-01

    North-south asymmetry of sunspot activity resulted in an asynchronous reversal of the Sun's polar fields in the current cycle. The asymmetry is also observed in the formation of polar coronal holes. A stable coronal hole was first formed at the South Pole, despite the later polar-field reversal there. The aim of this study is to understand processes making this situation possible. Synoptic magnetic maps from the Global Oscillation Network Group and corresponding coronal-hole maps from the Extreme ultraviolet Imaging Telescope aboard the Solar and Heliospheric Observatory and the Atmospheric Imaging Assembly aboard the Solar Dynamics Observatory are analyzed here to study a causal relationship between the decay of activity complexes, evolution of large-scale magnetic fields, and formation of coronal holes. Ensembles of coronal holes associated with decaying active regions and activity complexes are presented. These ensembles take part in global rearrangements of the Sun's open magnetic flux. In particular, the...

  3. A rapid and quantitative coat protein complex II vesicle formation assay using luciferase reporters.

    Science.gov (United States)

    Fromme, J Chris; Kim, Jinoh

    2012-02-15

    The majority of protein export from the endoplasmic reticulum (ER) is facilitated by coat protein complex II (COPII). The COPII proteins deform the ER membrane into vesicles at the ER exit sites. During the vesicle formation step, the COPII proteins load cargo molecules into the vesicles. Formation of COPII vesicles has been reconstituted in vitro in yeast and in mammalian systems. These in vitro COPII vesicle formation assays involve incubation of microsomal membranes and purified COPII proteins with nucleotides. COPII vesicles are separated from the microsomes by differential centrifugation. Interestingly, the efficiency of the COPII vesicle formation with purified recombinant mammalian COPII proteins is lower than that with cytosol, suggesting that an additional cytosolic factor(s) is involved in this process. Indeed, other studies have also implicated additional factors. To facilitate biochemical identification of such regulators, a rapid and quantitative COPII vesicle formation assay is necessary because the current assay is lengthy. To expedite this assay, we generated luciferase reporter constructs. The reporter proteins were packaged into COPII vesicles and yielded quantifiable luminescent signals, resulting in a rapid and quantitative COPII vesicle formation assay.

  4. Peculiarities of litter invertebrates’ multispecies complexes formation on the Khortitsa island (Zaporizhzhya province

    Directory of Open Access Journals (Sweden)

    D. О. Fedorchenko

    2008-02-01

    Full Text Available Peculiarities of litter invertebrates’ complexes formation under conditions of the Khortitsa National Reserve (Zaporizhzhya province are studied. The dispersion of taxonomic groups of different levels (families and species in litter mesofauna is swayed by the inter- and intrasystem factors; the largest influence has the power of litter and its humidity. The rate of ecological factors’ influence at different taxonomic levels may diverge.

  5. The role of eIF-4C in protein synthesis initiation complex formation

    NARCIS (Netherlands)

    Goumans, H.; Thomas, A.; Verhoeven, H.; Voorma, H.O.; Benne, R.

    1980-01-01

    eIF-4C has a pronounced stimulatory effect on initiation complex formation with native 80-S ribosomes (80-Sn) as the only source of ribosomal subunits, but only a small effect when washed 40-S subunits are used. eIF-4C is accessary to eIF-3 in dissociating 80-Sn ribosomes. eIF-4C is present on 40-

  6. Formation and Identification of Unresolved Complex Mixtures in Lacustrine Biodegraded Oil from Nanxiang Basin, China

    OpenAIRE

    Pengfei Guo; Sheng He; Shukui Zhu; Derong Chai; Shiyan Yin; Wei Dai; Wanfeng Zhang

    2014-01-01

    A comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC × GC/TOFMS) method has been developed for the formation and identification of unresolved complex mixtures (UCMs) in lacustrine biodegraded oils that with the same source rock, similar maturity, and increasing degradation rank from Nanxiang Basin, China. Normal alkanes, light hydrocarbons, isoprenoids, steranes, and terpanes are degraded gradually from oil B330 to oil G574. The compounds in biodegraded oil ...

  7. Microscopic Mechanism and Kinetics of Ice Formation at Complex Interfaces: Zooming in on Kaolinite

    CERN Document Server

    Sosso, Gabriele C; Donadio, Davide; Tribello, Gareth A; Michaelides, Angelos

    2016-01-01

    Most ice in nature forms thanks to impurities which boost the exceedingly low nucleation rate of pure supercooled water. However, the microscopic details of ice nucleation on these substances remain largely unknown. Here, we have unraveled the molecular mechanism and the kinetics of ice formation on kaolinite, a clay mineral playing a key role in climate science. We find that the formation of ice at strong supercooling in the presence of this clay is twenty orders of magnitude faster than homogeneous freezing. The critical nucleus is substantially smaller than that found for homogeneous nucleation and, in contrast to the predictions of classical nucleation theory (CNT), it has a strong 2D character. Nonetheless, we show that CNT describes correctly the formation of ice at this complex interface. Kaolinite also promotes the exclusive nucleation of hexagonal ice, as opposed to homogeneous freezing where a mixture of cubic and hexagonal polytypes is observed.

  8. Potentiometric studies on the complex formation of some Ln(III) ions with 4-nitrocatechol

    Energy Technology Data Exchange (ETDEWEB)

    Bhuyan, B.C.; Dubey, S.N. (Kurukshetra Univ. (India). Dept. of Chemistry)

    1981-07-01

    The interaction of La(III), Ce(III), Pr(III), Nd(III), Sm(III), Gd(III), Tb(III), Dy(III), Ho(III) and Y(III) with 4-nitrocatechol has been investigated potentiometrically in aqueous medium at 25deg and at ionic strengths of 0.05, 0.1, 0.15 and 0.2M (KNO/sub 3/). The proton-ligand formation constants and metal-ligand formation constants have been calculated using the Calvin-Bjerrum titration technique as modified by Irving and Rossotti. The thermodynamic formation constants have also been determined. The order of stabilities of the lanthanide complexes with the above ligand is found to be: La(III) < Ce(III) approximately Pr(III) < Nd(III) < Sm(III) < Gd(III) < Y(III) < Tb(III) < Dy(III) < Ho(III).

  9. True boundary for the formation of homoleptic transition-metal hydride complexes.

    Science.gov (United States)

    Takagi, Shigeyuki; Iijima, Yuki; Sato, Toyoto; Saitoh, Hiroyuki; Ikeda, Kazutaka; Otomo, Toshiya; Miwa, Kazutoshi; Ikeshoji, Tamio; Aoki, Katsutoshi; Orimo, Shin-ichi

    2015-05-04

    Despite many exploratory studies over the past several decades, the presently known transition metals that form homoleptic transition-metal hydride complexes are limited to the Groups 7-12. Here we present evidence for the formation of Mg3 CrH8 , containing the first Group 6 hydride complex [CrH7 ](5-) . Our theoretical calculations reveal that pentagonal-bipyramidal H coordination allows the formation of σ-bonds between H and Cr. The results are strongly supported by neutron diffraction and IR spectroscopic measurements. Given that the Group 3-5 elements favor ionic/metallic bonding with H, along with the current results, the true boundary for the formation of homoleptic transition-metal hydride complexes should be between Group 5 and 6. As the H coordination number generally tends to increase with decreasing atomic number of transition metals, the revised boundary suggests high potential for further discovery of hydrogen-rich materials that are of both technological and fundamental interest.

  10. Complexes of triggered star formation in supergiant shell of Holmberg II

    CERN Document Server

    Egorov, Oleg V; Moiseev, Alexei V; Shchekinov, Yuri A

    2016-01-01

    We report a detailed analysis of all regions of current star formation in the walls of the supergiant HI shell (SGS) in the galaxy Holmberg II based on observations with a scanning Fabry-Perot interferometer at the 6-m SAO RAS telescope. We compare the structure and kinematics of ionized gas with that of atomic hydrogen and with the stellar population of the SGS. Our deep H$\\alpha$ images and archival images taken by the HST demonstrate that current star formation episodes are larger and more complicated than previously thought: they represent unified star-forming complexes with sizes of several hundred pc rather than 'chains' of separate bright nebulae in the walls of the SGS. The fact that we are dealing with unified complexes is evidenced by identified faint shell-like structures of ionized and neutral gas which connect several distinct bright HII regions. Formation of such complexes is due to the feedback of stars with very inhomogeneous ambient gas in the walls of the SGS. The arguments supporting an ide...

  11. Formylglycinamide Ribonucleotide Amidotransferase from Thermotoga maritima: Structural Insights into Complex Formation

    Energy Technology Data Exchange (ETDEWEB)

    Morar, Mariya; Hoskins, Aaron A.; Stubbe, JoAnne; Ealick, Steven E. (MIT); (Cornell)

    2008-10-02

    In the fourth step of the purine biosynthetic pathway, formyl glycinamide ribonucleotide (FGAR) amidotransferase, also known as PurL, catalyzes the conversion of FGAR, ATP, and glutamine to formyl glycinamidine ribonucleotide (FGAM), ADP, P{sub i}, and glutamate. Two forms of PurL have been characterized, large and small. Large PurL, present in most Gram-negative bacteria and eukaryotes, consists of a single polypeptide chain and contains three major domains: the N-terminal domain, the FGAM synthetase domain, and the glutaminase domain, with a putative ammonia channel located between the active sites of the latter two. Small PurL, present in Gram-positive bacteria and archaea, is structurally homologous to the FGAM synthetase domain of large PurL, and forms a complex with two additional gene products, PurQ and PurS. The structure of the PurS dimer is homologous with the N-terminal domain of large PurL, while PurQ, whose structure has not been reported, contains the glutaminase activity. In Bacillus subtilis, the formation of the PurLQS complex is dependent on glutamine and ADP and has been demonstrated by size-exclusion chromatography. In this work, a structure of the PurLQS complex from Thermotoga maritima is described revealing a 2:1:1 stoichiometry of PurS:Q:L, respectively. The conformational changes observed in TmPurL upon complex formation elucidate the mechanism of metabolite-mediated recruitment of PurQ and PurS. The flexibility of the PurS dimer is proposed to play a role in the activation of the complex and the formation of the ammonia channel. A potential path for the ammonia channel is identified.

  12. FORMATION AND RECONDENSATION OF COMPLEX ORGANIC MOLECULES DURING PROTOSTELLAR LUMINOSITY OUTBURSTS

    Energy Technology Data Exchange (ETDEWEB)

    Taquet, Vianney [Leiden Observatory, Leiden University, P.O. Box 9513, 2300-RA Leiden (Netherlands); Wirström, Eva S. [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-439 92 Onsala (Sweden); Charnley, Steven B. [Astrochemistry Laboratory and The Goddard Center for Astrobiology, Mailstop 691, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20770 (United States)

    2016-04-10

    During the formation of stars, the accretion of surrounding material toward the central object is thought to undergo strong luminosity outbursts followed by long periods of relative quiescence, even at the early stages of star formation when the protostar is still embedded in a large envelope. We investigated the gas-phase formation and recondensation of the complex organic molecules (COMs) di-methyl ether and methyl formate, induced by sudden ice evaporation processes occurring during luminosity outbursts of different amplitudes in protostellar envelopes. For this purpose, we updated a gas-phase chemical network forming COMs in which ammonia plays a key role. The model calculations presented here demonstrate that ion–molecule reactions alone could account for the observed presence of di-methyl ether and methyl formate in a large fraction of protostellar cores without recourse to grain-surface chemistry, although they depend on uncertain ice abundances and gas-phase reaction branching ratios. In spite of the short outburst timescales of about 100 years, abundance ratios of the considered species higher than 10% with respect to methanol are predicted during outbursts due to their low binding energies relative to water and methanol which delay their recondensation during cooling. Although the current luminosity of most embedded protostars would be too low to produce complex organics in the hot-core regions that are observable with current sub-millimetric interferometers, previous luminosity outburst events would induce the formation of COMs in extended regions of protostellar envelopes with sizes increasing by up to one order of magnitude.

  13. [Regularities of formation of chlorophyll-human serum albumin functionally active complexes in the aqueous medium].

    Science.gov (United States)

    Semichaevskiĭ, V D

    1975-01-01

    In the system with constant content of the chlorophyll a and increasing amounts of human serum albumin, dependence of pigment incorporation into the complex upon interaction of its aqueous associates with protein solutions was studied by applying the gel filtration on Sephadex G-75 and by measuring light scattering and rate of sensitized photoreduction of the methyl red by ascorbic-acid. The curves were obtained after extraction of the chlorophyll by acetone from dry pigment-protein films formed after desiccation of the aqueous systems. Sigmoid character of the above dependences, their linearization in Hill's coordinates and the value of cooperativity coefficient close to 2 testifies in favour of the cooperative character of the complex formation, two pigment molecules reacting with a single protein molecule. Measurement of adsorption isotherms and their treatment with use of the Brunauer-Emmett-Teller theory of polymolecular adsorption make it possible to evaluate the maximum molar ratio of the pigment to the protein in the complex (close to 2). The pigment-pigment interaction suggests that the chlorophyll molecules adsorbed on the protein are in the state of loosely packed dimers. Deaggregation of aqueus pigment associates by the protein in the course of complex formation results in a considerable increase of the protosensitizing chlorophyll activity.

  14. Perfluoroalkyl Cobalt(III) Fluoride and Bis(perfluoroalkyl) Complexes: Catalytic Fluorination and Selective Difluorocarbene Formation.

    Science.gov (United States)

    Leclerc, Matthew C; Bayne, Julia M; Lee, Graham M; Gorelsky, Serge I; Vasiliu, Monica; Korobkov, Ilia; Harrison, Daniel J; Dixon, David A; Baker, R Tom

    2015-12-30

    Four perfluoroalkyl cobalt(III) fluoride complexes have been synthesized and characterized by elemental analysis, multinuclear NMR spectroscopy, X-ray crystallography, and powder X-ray diffraction. The remarkable cobalt fluoride (19)F NMR chemical shifts (-716 to -759 ppm) were studied computationally, and the contributing paramagnetic and diamagnetic factors were extracted. Additionally, the complexes were shown to be active in the catalytic fluorination of p-toluoyl chloride. Furthermore, two examples of cobalt(III) bis(perfluoroalkyl)complexes were synthesized and their reactivity studied. Interestingly, abstraction of a fluoride ion from these complexes led to selective formation of cobalt difluorocarbene complexes derived from the trifluoromethyl ligand. These electrophilic difluorocarbenes were shown to undergo insertion into the remaining perfluoroalkyl fragment, demonstrating the elongation of a perfluoroalkyl chain arising from a difluorocarbene insertion on a cobalt metal center. The reactions of both the fluoride and bis(perfluoroalkyl) complexes provide insight into the potential catalytic applications of these model systems to form small fluorinated molecules as well as fluoropolymers.

  15. Moessbauer study of peroxynitrito complex formation with Fe{sup III}-chelates

    Energy Technology Data Exchange (ETDEWEB)

    Homonnay, Zoltan, E-mail: homonnay@ludens.elte.hu; Buszlai, Peter; Nador, Judit [Eoetvoes University, Institute of Chemistry (Hungary); Sharma, Virender K. [Florida Institute of Technology (United States); Kuzmann, Erno; Vertes, Attila [Eoetvoes University, Institute of Chemistry (Hungary)

    2012-03-15

    The reaction of the {mu}-oxo-diiron(III)-L complex (L = EDTA, ethylene diamine tetraacetate, HEDTA, hydroxyethyl ethylene diamine triacetate, and CyDTA, cyclohexane diamine tetraacetate) with peroxynitrite in alkaline solution was studied by Moessbauer spectroscopy using rapid-freezing technique. These complexes yield an (L)Fe{sup III}({eta}{sup 2}-O{sub 2}){sup 3-} complex ion when they react with hydrogen peroxide and the formation of the peroxide adduct results in a deep purple coloration of the solution. The same color appears when the reaction occurs with peroxinitrite. Although spectrophotometry indicated some difference between the molar extinction coefficients of the peroxo and the peroxinitrito adducts, the Moessbauer parameters proved to be the same within experimental error. It is concluded that the peroxynitrite ion decomposes when reacting with Fe{sup III}(L) and the peroxo adduct forms.

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

    Directory of Open Access Journals (Sweden)

    Lin Chih-Li

    2010-02-01

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

  17. cAMP prevents TNF-induced apoptosis through inhibiting DISC complex formation in rat hepatocytes

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharjee, Rajesh [Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA 15213 (United States); Xiang, Wenpei [Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA 15213 (United States); Family Planning Research Institute, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People' s Republic of China (China); Wang, Yinna [Vascular Medicine Institute, University of Pittsburgh School of Medicine, 10051-5A BST 3, 3501 Fifth Avenue, Pittsburgh, PA 15261 (United States); Zhang, Xiaoying [Department of Medicine/Endocrinology Division, University of Pittsburgh Medical Center, 200 Lothrop St., Pittsburgh, PA 15213 (United States); Billiar, Timothy R., E-mail: billiartr@upmc.edu [Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA 15213 (United States)

    2012-06-22

    Highlights: Black-Right-Pointing-Pointer cAMP blocks cell death induced by TNF and actinomycin D in cultured hepatocytes. Black-Right-Pointing-Pointer cAMP blocks NF-{kappa}B activation induced by TNF and actinomycin D. Black-Right-Pointing-Pointer cAMP blocks DISC formation following TNF and actinomycin D exposure. Black-Right-Pointing-Pointer cAMP blocks TNF signaling at a proximal step. -- Abstract: Tumor necrosis factor {alpha} (TNF) is a pleiotropic proinflammatory cytokine that plays a role in immunity and the control of cell proliferation, cell differentiation, and apoptosis. The pleiotropic nature of TNF is due to the formation of different signaling complexes upon the binding of TNF to its receptor, TNF receptor type 1 (TNFR1). TNF induces apoptosis in various mammalian cells when the cells are co-treated with a transcription inhibitor like actinomycin D (ActD). When TNFR1 is activated, it recruits an adaptor protein, TNF receptor-associated protein with death domain (TRADD), through its cytoplasmic death effector domain (DED). TRADD, in turn, recruits other signaling proteins, including TNF receptor-associated protein 2 (TRAF2) and receptor-associated protein kinase (RIPK) 1, to form a complex. Subsequently, this complex combines with FADD and procaspase-8, converts into a death-inducing signaling complex (DISC) to induce apoptosis. Cyclic AMP (cAMP) is a second messenger that regulates various cellular processes such as cell proliferation, gene expression, and apoptosis. cAMP analogues are reported to act as anti-apoptotic agents in various cell types, including hepatocytes. We found that a cAMP analogue, dibutyryl cAMP (db-cAMP), inhibits TNF + ActD-induced apoptosis in rat hepatocytes. The protein kinase A (PKA) inhibitor KT-5720 reverses this inhibitory effect of cAMP on apoptosis. Cytoprotection by cAMP involves down-regulation of various apoptotic signal regulators like TRADD and FADD and inhibition of caspase-8 and caspase-3 cleavage. We also found

  18. CARBON DIOXIDE INFLUENCE ON THE THERMAL FORMATION OF COMPLEX ORGANIC MOLECULES IN INTERSTELLAR ICE ANALOGS

    Energy Technology Data Exchange (ETDEWEB)

    Vinogradoff, V.; Fray, N.; Bouilloud, M.; Cottin, H. [LISA Laboratoire Interuniversitaire des Systèmes Atmosphériques, UMR CNRS 7583, Université Paris Est Créteil (UPEC), Université Paris Diderot (UPD), Institut Pierre Simon Laplace, Labex ESEP, Paris (France); Duvernay, F.; Chiavassa, T., E-mail: vvinogradoff@mnhn.fr [PIIM, Laboratoire de Physique des Interactions Ioniques et Moléculaires, Université Aix-Marseille, UMR CNRS 7345, Marseille (France)

    2015-08-20

    Interstellar ices are submitted to energetic processes (thermal, UV, and cosmic-ray radiations) producing complex organic molecules. Laboratory experiments aim to reproduce the evolution of interstellar ices to better understand the chemical changes leading to the reaction, formation, and desorption of molecules. In this context, the thermal evolution of an interstellar ice analogue composed of water, carbon dioxide, ammonia, and formaldehyde is investigated. The ice evolution during the warming has been monitored by IR spectroscopy. The formation of hexamethylenetetramine (HMT) and polymethylenimine (PMI) are observed in the organic refractory residue left after ice sublimation. A better understanding of this result is realized with the study of another ice mixture containing methylenimine (a precursor of HMT) with carbon dioxide and ammonia. It appears that carbamic acid, a reaction product of carbon dioxide and ammonia, plays the role of catalyst, allowing the reactions toward HMT and PMI formation. This is the first time that such complex organic molecules (HMT, PMI) are produced from the warming (without VUV photolysis or irradiation with energetic particles) of abundant molecules observed in interstellar ices (H{sub 2}O, NH{sub 3}, CO{sub 2}, H{sub 2}CO). This result strengthens the importance of thermal reactions in the ices’ evolution. HMT and PMI, likely components of interstellar ices, should be searched for in the pristine objects of our solar system, such as comets and carbonaceous chondrites.

  19. Formation mechanism and biological activity of novel thiolated human-like collagen iron complex.

    Science.gov (United States)

    Zhu, Chenhui; Liu, Lingyun; Deng, Jianjun; Ma, Xiaoxuan; Hui, Junfeng; Fan, Daidi

    2016-03-01

    To develop an iron supplement that is effectively absorbed and utilized, thiolated human-like collagen was created to improve the iron binding capacity of human-like collagen. A thiolated human-like collagen-iron complex was prepared in a phosphate buffer, and one mole of thiolated human-like collagen-iron possessed approximately 28.83 moles of iron. The characteristics of thiolated human-like collagen-iron were investigated by ultraviolet-visible absorption spectroscopy, Fourier transform infrared spectroscopy, circular dichroism, and differential scanning calorimetry. The results showed that the thiolated human-like collagen-iron complex retained the secondary structure of human-like collagen and had greater thermodynamic stability than human-like collagen, although interactions between iron ions and human-like collagen occurred during the formation of the complex. In addition, to evaluate the bioavailability of thiolated human-like collagen-iron, an in vitro Caco-2 cell model and an in vivo iron deficiency anemia mouse model were employed. The data demonstrated that the thiolated human-like collagen-iron complex exhibited greater bioavailability and was more easily utilized than FeSO4, ferric ammonium citrate, or ferrous glycinate. These results indicated that the thiolated human-like collagen-iron complex is a potential iron supplement in the biomedical field.

  20. Young stellar population and ongoing star formation in the HII complex Sh2-252

    CERN Document Server

    Jose, Jessy; Samal, M R; Ojha, D K; Ogura, K; Kim, J S; Kobayashi, N; Goyal, A; Chauhan, N; Eswaraiah, C

    2013-01-01

    In this paper an extensive survey of the star forming complex Sh2-252 has been undertaken with an aim to explore its hidden young stellar population as well as to understand the structure and star formation history. This complex is composed of five embedded clusters associated with the sub-regions A, C, E, NGC 2175s and Teu 136. Using 2MASS-NIR and Spitzer-IRAC, MIPS photometry we identified 577 young stellar objects (YSOs), of which, 163 are Class I, 400 are Class II and 14 are transition disk YSOs. Spatial distribution of the candidate YSOs shows that they are mostly clustered around the sub-regions in the western half of the complex, suggesting enhanced star formation activity towards its west. Using the spectral energy distribution and optical colour-magnitude diagram based age analyses, we derived probable evolutionary status of the sub-regions of Sh2-252. Our analysis shows that the region A is the youngest (~ 0.5 Myr), the regions B, C and E are of similar evolutionary stage (~ 1-2 Myr) and the cluster...

  1. Quantitative serine protease assays based on formation of copper(II)-oligopeptide complexes.

    Science.gov (United States)

    Ding, Xiaokang; Yang, Kun-Lin

    2015-01-07

    A quantitative protease assay based on the formation of a copper-oligopeptide complex is developed. In this assay, when a tripeptide GGH fragment is cleaved from an oligopeptide chain by serine proteases, the tripeptide quickly forms a pink GGH/Cu(2+) complex whose concentration can be determined quantitatively by using UV-Vis spectroscopy. Therefore, activities of serine proteases can be determined from the formation rate of the GGH/Cu(2+) complex. This principle can be used to detect the presence of serine protease in a real-time manner, or measure proteolytic activities of serine protease cleaving different oligopeptide substrates. For example, by using this assay, we demonstrate that trypsin, a model serine protease, is able to cleave two oligopeptides GGGGKGGH () and GGGGRGGH (). However, the specificity constant (kcat/Km) for is higher than that of (6.4 × 10(3) mM(-1) min(-1)vs. 1.3 × 10(3) mM(-1) min(-1)). This result shows that trypsin is more specific toward arginine (R) than lysine (K) in the oligopeptide sequence.

  2. SOHLH2 is essential for synaptonemal complex formation during spermatogenesis in early postnatal mouse testes.

    Science.gov (United States)

    Park, Miree; Lee, Youngeun; Jang, Hoon; Lee, Ok-Hee; Park, Sung-Won; Kim, Jae-Hwan; Hong, Kwonho; Song, Hyuk; Park, Se-Pill; Park, Yun-Yong; Ko, Jung Jae; Choi, Youngsok

    2016-02-12

    Spermatogenesis- and oogenesis-specific helix-loop-helix transcription factor 2 (SOHLH2) is exclusively expressed in germ cells of the gonads. Previous studies show that SOHLH2 is critical for spermatogenesis in mouse. However, the regulatory mechanism of SOHLH2 during early spermatogenesis is poorly understood. In the present study, we analyzed the gene expression profile of the Sohlh2-deficient testis and examined the role of SOHLH2 during spermatogenesis. We found 513 genes increased in abundance, while 492 genes decreased in abundance in 14-day-old Sohlh2-deficient mouse testes compared to wildtype mice. Gene ontology analysis revealed that Sohlh2 disruption effects the relative abundance of various meiotic genes during early spermatogenesis, including Spo11, Dmc1, Msh4, Prdm9, Sycp1, Sycp2, Sycp3, Hormad1, and Hormad2. Western blot analysis and immunostaining showed that SYCP3, a component of synaptonemal complex, was significantly less abundant in Sohlh2-deficient spermatocytes. We observed a lack of synaptonemal complex formation during meiosis in Sohlh2-deficient spermatocytes. Furthermore, we found that SOHLH2 interacted with two E-boxes on the mouse Sycp1 promoter and Sycp1 promoter activity increased with ectopically expressed SOHLH2. Taken together, our data suggest that SOHLH2 is critical for the formation of synaptonemal complexes via its regulation of Sycp1 expression during mouse spermatogonial differentiation.

  3. The plant cell cycle: Pre-Replication complex formation and controls.

    Science.gov (United States)

    Brasil, Juliana Nogueira; Costa, Carinne N Monteiro; Cabral, Luiz Mors; Ferreira, Paulo C G; Hemerly, Adriana S

    2017-03-16

    The multiplication of cells in all living organisms requires a tight regulation of DNA replication. Several mechanisms take place to ensure that the DNA is replicated faithfully and just once per cell cycle in order to originate through mitoses two new daughter cells that contain exactly the same information from the previous one. A key control mechanism that occurs before cells enter S phase is the formation of a pre-replication complex (pre-RC) that is assembled at replication origins by the sequential association of the origin recognition complex, followed by Cdt1, Cdc6 and finally MCMs, licensing DNA to start replication. The identification of pre-RC members in all animal and plant species shows that this complex is conserved in eukaryotes and, more importantly, the differences between kingdoms might reflect their divergence in strategies on cell cycle regulation, as it must be integrated and adapted to the niche, ecosystem, and the organism peculiarities. Here, we provide an overview of the knowledge generated so far on the formation and the developmental controls of the pre-RC mechanism in plants, analyzing some particular aspects in comparison to other eukaryotes.

  4. Mode of formation and structural features of DNA-cationic liposome complexes used for transfection.

    Science.gov (United States)

    Gershon, H; Ghirlando, R; Guttman, S B; Minsky, A

    1993-07-20

    Complexes formed between cationic liposomes and nucleic acids represent a highly efficient vehicle for delivery of DNA and RNA molecules into a large variety of eukaryotic cells. By using fluorescence, gel electrophoresis, and metal-shadowing electron microscopy techniques, the factors that affect the, yet unclear, interactions between DNA and cationic liposomes as well as the structural features of the resulting complexes have been elucidated. A model is suggested according to which cationic liposomes bind initially to DNA molecules to form clusters of aggregated vesicles along the nucleic acids. At a critical liposome density, two processes occur, namely, DNA-induced membrane fusion, indicated by lipid mixing studies, and liposome-induced DNA collapse, pointed out by the marked cooperativity of the encapsulation processes, by their modulations by DNA-condensing agents, and also by their conspicuous independence upon DNA length. The DNA collapse leads to the formation of condensed structures which can be completely encapsulated within the fused lipid bilayers in a fast, highly cooperative process since their exposed surface is substantially smaller than that of extended DNA molecules. The formation of the transfecting DNA-liposome complexes in which the nucleic acids are fully encapsulated within a positively-charged lipid bilayer is proposed, consequently, to be dominated by mutual effects exerted by the DNA and the cationic liposomes, leading to interrelated lipid fusion and DNA collapse.

  5. Decay of Activity Complexes, Formation of Unipolar Magnetic Regions, and Coronal Holes in Their Causal Relation

    Science.gov (United States)

    Golubeva, E. M.; Mordvinov, A. V.

    2016-12-01

    The peculiar development of solar activity in the current cycle resulted in an asynchronous reversal of the Sun's polar fields. The asymmetry is also observed in the formation of polar coronal holes. A stable coronal hole was first formed at the South Pole, despite the later polar-field reversal there. The aim of this study is to understand the processes making this situation possible. Synoptic magnetic maps from the Global Oscillation Network Group and corresponding coronal-hole maps from the Extreme ultraviolet Imaging Telescope onboard the Solar and Heliospheric Observatory and the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory are analyzed here to study the causal relationship between the decay of activity complexes, evolution of large-scale magnetic fields, and formation of coronal holes. Ensembles of coronal holes associated with decaying active regions and activity complexes are presented. These ensembles take part in global rearrangements of the Sun's open magnetic flux. In particular, the south polar coronal hole was formed from an ensemble of coronal holes that came into existence after the decay of multiple activity complexes observed during 2014.

  6. Solid inclusion complexes of vanillin with cyclodextrins: their formation, characterization, and high-temperature stability.

    Science.gov (United States)

    Kayaci, Fatma; Uyar, Tamer

    2011-11-09

    This study reports the formation of solid vanillin/cyclodextrin inclusion complexes (vanillin/CD ICs) with the aim to enhance the thermal stability and sustained release of vanillin by inclusion complexation. The solid vanillin/CD ICs with three types of CDs (α-CD, β-CD, and γ-CD) were prepared using the freeze-drying method; in addition, a coprecipitation method was also used in the case of γ-CD. The presence of vanillin in CD ICs was confirmed by FTIR and (1)H NMR studies. Moreover, (1)H NMR study elucidated that the complexation stoichiometry for both vanillin/β-CD IC and vanillin/γ-CD IC was a 1:1 molar ratio, whereas it was 0.625:1 for vanillin/α-CD IC. XRD studies have shown channel-type arrangement for CD molecules, and no diffraction peak for free vanillin was observed for vanillin/β-CD IC and vanillin/γ-CD IC, indicating that complete inclusion complexation was successfully achieved for these CD ICs. In the case of vanillin/α-CD IC, the sample was mostly amorphous and some uncomplexed vanillin was present, suggesting that α-CD was not very effective for complexation with vanillin compared to β-CD and γ-CD. Furthermore, DSC studies for vanillin/β-CD IC and vanillin/γ-CD IC have shown no melting point for vanillin, elucidating the true complex formation, whereas a melting point for vanillin was recorded for vanillin/α-CD IC, confirming the presence of some uncomplexed vanillin in this sample. TGA thermograms indicated that thermal evaporation/degradation of vanillin occurred over a much higher temperature range (150-300 °C) for vanillin/CD ICs samples when compared to pure vanillin (80-200 °C) or vanillin/CD physical mixtures, signifying that the thermal stability of vanillin was increased due to the inclusion complexation with CDs. Moreover, headspace GC-MS analyses indicated that the release of vanillin was sustained at higher temperatures in the case of vanillin/CD ICs due to the inclusion complexation when compared to vanillin

  7. Complex Organic Molecules Formation in Space Through Gas Phase Reactions: A Theoretical Approach

    Science.gov (United States)

    Redondo, Pilar; Barrientos, Carmen; Largo, Antonio

    2017-02-01

    Chemistry in the interstellar medium (ISM) is capable of producing complex organic molecules (COMs) of great importance to astrobiology. Gas phase and grain surface chemistry almost certainly both contribute to COM formation. Amino acids as building blocks of proteins are some of the most interesting COMs. The simplest one, glycine, has been characterized in meteorites and comets and, its conclusive detection in the ISM seems to be highly plausible. In this work, we analyze the gas phase reaction of glycine and {{{CH}}5}+ to establish the role of this process in the formation of alanine or other COMs in the ISM. Formation of protonated α- and β-alanine in spite of being exothermic processes is not viable under interstellar conditions because the different paths leading to these isomers present net activation energies. Nevertheless, glycine can evolve to protonated 1-imide-2, 2-propanediol, protonated amino acetone, protonated hydroxyacetone, and protonated propionic acid. However, formation of acetic acid and protonated methylamine is also a favorable process and therefore will be a competitive channel with the evolution of glycine to COMs.

  8. High-throughput metagenomic technologies for complex microbial community analysis: open and closed formats.

    Science.gov (United States)

    Zhou, Jizhong; He, Zhili; Yang, Yunfeng; Deng, Ye; Tringe, Susannah G; Alvarez-Cohen, Lisa

    2015-01-27

    Understanding the structure, functions, activities and dynamics of microbial communities in natural environments is one of the grand challenges of 21st century science. To address this challenge, over the past decade, numerous technologies have been developed for interrogating microbial communities, of which some are amenable to exploratory work (e.g., high-throughput sequencing and phenotypic screening) and others depend on reference genes or genomes (e.g., phylogenetic and functional gene arrays). Here, we provide a critical review and synthesis of the most commonly applied "open-format" and "closed-format" detection technologies. We discuss their characteristics, advantages, and disadvantages within the context of environmental applications and focus on analysis of complex microbial systems, such as those in soils, in which diversity is high and reference genomes are few. In addition, we discuss crucial issues and considerations associated with applying complementary high-throughput molecular technologies to address important ecological questions.

  9. The effect of the Ti (IV-citrate complex on staphylococcus aureus growth and biofilm formation

    Directory of Open Access Journals (Sweden)

    Gritsenko Viktor A.

    2015-01-01

    Full Text Available The primary objective of this study was to investigate the influence of the Ti (IV-citrate complex on growth dynamics and biofilm formation of S. aureus. Speciation analysis was performed in order to estimate the structure of the Ti complex existing in citrate solutions at near-physiological pH. It is estimated that the fully deprotonated tris(citratetitanate ion [Ti(C6H4O73]8- predominates in solution at pH 6.46-7.44, and that this is most probably the biologically active form of Ti(IV-citrate. In in vitro experiments, increasing concentrations of citric acid solutions (0.05, 0.005, 0.0005 M, served as positive controls, while the effects of respective concentrations of Ti(IV-citrate were examined. The obtained results indicate that citrate decreased S. aureus 48 growth at all studied concentrations, whereas S. aureus 44 growth was decreased only by high concentrations of citrate (0.05M. Incubation of S. aureus culture with Ti(IV-citrate significantly potentiated citrate-induced effects. Ti(IV-citrate significantly altered specific bacterial growth rate in a similar manner. The most significant growth reduction was observed at the initial period of bacterial growth. At the same time, the opposite effect was detected in investigations of the effect of citrate and Ti(IV-citrate on S. aureus biofilm formation. Citric acid suppressed S. aureus biofilm formation, whereas Ti(IV-citrate displayed a significant stimulatory effect. Our findings suggest that Ti(IV-citrate possesses a more pronounced biological effect than citrate. The proposed mechanism of this action is activation of complex transport into the cell and induction of oxidative stress. However, the exact mechanism of Ti(IV-citrate biological action on bacterial cultures remains unknown.

  10. Electrochemistry of metal complexes applications from electroplating to oxide layer formation

    CERN Document Server

    Survila, Arvydas

    2015-01-01

    This book aims to sequentially cover all the major stages of electrochemical processes (mass transport, adsorption, charge transfer), with a special emphasis on their deep interrelation. Starting with general considerations on equilibria in solutions and at interfaces as well as on mass transport, the text acquaints readers with the theory and common experimental practice for studying electrochemical reactions of metals complexes. The core part of the book deals with all important aspects of electroplating, including a systematic discussion of co-deposition of metals and formation of alloys.

  11. Peculiarities of latent inhibition formation in SHR rats in conditioned task of different complexity.

    Science.gov (United States)

    Kostyunina, N V; Loskutova, L V

    2012-05-01

    Inhibition of attention to irrelevant stimuli was studied in SHR rats using latent inhibition test. Latent inhibition was formed in two types of conditioned tasks with different levels of complexity and stress. Passive and active avoidance conditioning was preceded by preexposure to conditioned stimulus consisting of 20 and 100 non-reinforced presentations, respectively. Control Wistar rats demonstrated successful formation of latent inhibition in both tasks. SHR rats showed different degree of disruption of latent inhibition depending on the type of behavioral task. We assume that learning defect in these animals in respect to both novel and preexposed conditioned stimuli is associated with the lack of behavioral inhibition.

  12. Basic building units, self-assembly and crystallization in the formation of complex inorganic open architectures

    Indian Academy of Sciences (India)

    C N R Rao

    2001-10-01

    Careful investigations of open-framework metal phosphates reveal that the formation of these complex architectures is likely to involve a process wherein one-dimensional ladders or chains, and possibly zero-dimens ional monomers, transform to higher dimensional structures. The one-dimensional ladder appears to be the primary building unit of these structures. At one stage of the building-up process, spontaneous self-assembly of a low-dimensional structure such as the ladder seems to occur, followed by crys tallization of a two- or three-dimensional structure. Accordingly, many of the higher dimensional structures retain the structural features of the 1D structure, indicating the occurrence of self-assembly. These findings mark the beginnings of our understan ding of complex supramolecular inorganic materials.

  13. Trans-complex formation by proteolipid channels in the terminal phase of membrane fusion

    DEFF Research Database (Denmark)

    Peters, C; Bayer, M J; Bühler, S;

    2001-01-01

    SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptors) and Rab-GTPases, together with their cofactors, mediate the attachment step in the membrane fusion of vesicles. But how bilayer mixing--the subsequent core process of fusion--is catalysed remains unclear. Ca2+/calmodu......SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptors) and Rab-GTPases, together with their cofactors, mediate the attachment step in the membrane fusion of vesicles. But how bilayer mixing--the subsequent core process of fusion--is catalysed remains unclear. Ca2......-complex formation occurs downstream from trans-SNARE pairing, and depends on both the Rab-GTPase Ypt7 and calmodulin. The maintenance of existing complexes and completion of fusion are independent of trans-SNARE pairs. Reconstituted proteolipids form sealed channels, which can expand to form aqueous pores in a Ca2...

  14. Formation and dynamics of "waterproof" photoluminescent complexes of rare earth ions in crowded environment.

    Science.gov (United States)

    Ignatova, Tetyana; Blades, Michael; Duque, Juan G; Doorn, Stephen K; Biaggio, Ivan; Rotkin, Slava V

    2014-12-28

    Understanding behavior of rare-earth ions (REI) in crowded environments is crucial for several nano- and bio-technological applications. Evolution of REI photoluminescence (PL) in small compartments inside a silica hydrogel, mimic to a soft matter bio-environment, has been studied and explained within a solvation model. The model uncovered the origin of high PL efficiency to be the formation of REI complexes, surrounded by bile salt (DOC) molecules. Comparative study of these REI-DOC complexes in bulk water solution and those enclosed inside the hydrogel revealed a strong correlation between an up to 5×-longer lifetime of REIs and appearance of the DOC ordered phase, further confirmed by dynamics of REI solvation shells, REI diffusion experiments and morphological characterization of microstructure of the hydrogel.

  15. Formation, Structure and In Vitro Antitumour Activity of a Novel Binuclear Organotin Complex

    Institute of Scientific and Technical Information of China (English)

    Lai Jin TIAN; Yu Xi SUN; Guo Ming YANG; Bo Chu QIAN; Zhi Cai SHANG

    2005-01-01

    A 1:1 reaction of triphenyltin chloride with potassium N-[(3,5-dibromo-2-hydroxyl-phenyl)methylene]valinate in benzene led to the formation of a novel mixed organotin dinuclear phenyl-tin bond cleavage process. In the complex, there are two distinct types of carboxylate moieties and a trans-O2SnC2N and a trans-O2SnC3 in distorted trigonal bipyramidal geometries were bridged by a carboxylate group. In vitro antimmor activity of the complex against three human tumour cell lines (HeLa, CoLo205 and MCF-7) was found to be much higher than cis-platin used in clinic.

  16. Radiation increases the cellular uptake of exosomes through CD29/CD81 complex formation

    Energy Technology Data Exchange (ETDEWEB)

    Hazawa, Masaharu; Tomiyama, Kenichi; Saotome-Nakamura, Ai; Obara, Chizuka; Yasuda, Takeshi; Gotoh, Takaya; Tanaka, Izumi; Yakumaru, Haruko; Ishihara, Hiroshi; Tajima, Katsushi, E-mail: tajima@nirs.go.jp

    2014-04-18

    Highlights: • Radiation increases cellular uptake of exosomes. • Radiation induces colocalization of CD29 and CD81. • Exosomes selectively bind the CD29/CD81 complex. • Radiation increases the cellular uptake of exosomes through CD29/CD81 complex formation. - Abstract: Exosomes mediate intercellular communication, and mesenchymal stem cells (MSC) or their secreted exosomes affect a number of pathophysiologic states. Clinical applications of MSC and exosomes are increasingly anticipated. Radiation therapy is the main therapeutic tool for a number of various conditions. The cellular uptake mechanisms of exosomes and the effects of radiation on exosome–cell interactions are crucial, but they are not well understood. Here we examined the basic mechanisms and effects of radiation on exosome uptake processes in MSC. Radiation increased the cellular uptake of exosomes. Radiation markedly enhanced the initial cellular attachment to exosomes and induced the colocalization of integrin CD29 and tetraspanin CD81 on the cell surface without affecting their expression levels. Exosomes dominantly bound to the CD29/CD81 complex. Knockdown of CD29 completely inhibited the radiation-induced uptake, and additional or single knockdown of CD81 inhibited basal uptake as well as the increase in radiation-induced uptake. We also examined possible exosome uptake processes affected by radiation. Radiation-induced changes did not involve dynamin2, reactive oxygen species, or their evoked p38 mitogen-activated protein kinase-dependent endocytic or pinocytic pathways. Radiation increased the cellular uptake of exosomes through CD29/CD81 complex formation. These findings provide essential basic insights for potential therapeutic applications of exosomes or MSC in combination with radiation.

  17. Gas Phase Reactions of Ions Derived from Anionic Uranyl Formate and Uranyl Acetate Complexes

    Science.gov (United States)

    Perez, Evan; Hanley, Cassandra; Koehler, Stephen; Pestok, Jordan; Polonsky, Nevo; Van Stipdonk, Michael

    2016-12-01

    The speciation and reactivity of uranium are topics of sustained interest because of their importance to the development of nuclear fuel processing methods, and a more complete understanding of the factors that govern the mobility and fate of the element in the environment. Tandem mass spectrometry can be used to examine the intrinsic reactivity (i.e., free from influence of solvent and other condensed phase effects) of a wide range of metal ion complexes in a species-specific fashion. Here, electrospray ionization, collision-induced dissociation, and gas-phase ion-molecule reactions were used to create and characterize ions derived from precursors composed of uranyl cation (UVIO2 2+) coordinated by formate or acetate ligands. Anionic complexes containing UVIO2 2+ and formate ligands fragment by decarboxylation and elimination of CH2=O, ultimately to produce an oxo-hydride species [UVIO2(O)(H)]-. Cationic species ultimately dissociate to make [UVIO2(OH)]+. Anionic complexes containing acetate ligands exhibit an initial loss of acetyloxyl radical, CH3CO2•, with associated reduction of uranyl to UVO2 +. Subsequent CID steps cause elimination of CO2 and CH4, ultimately to produce [UVO2(O)]-. Loss of CH4 occurs by an intra-complex H+ transfer process that leaves UVO2 + coordinated by acetate and acetate enolate ligands. A subsequent dissociation step causes elimination of CH2=C=O to leave [UVO2(O)]-. Elimination of CH4 is also observed as a result of hydrolysis caused by ion-molecule reaction with H2O. The reactions of other anionic species with gas-phase H2O create hydroxyl products, presumably through the elimination of H2.

  18. Hormad1 mutation disrupts synaptonemal complex formation, recombination, and chromosome segregation in mammalian meiosis.

    Science.gov (United States)

    Shin, Yong-Hyun; Choi, Youngsok; Erdin, Serpil Uckac; Yatsenko, Svetlana A; Kloc, Malgorzata; Yang, Fang; Wang, P Jeremy; Meistrich, Marvin L; Rajkovic, Aleksandar

    2010-11-04

    Meiosis is unique to germ cells and essential for reproduction. During the first meiotic division, homologous chromosomes pair, recombine, and form chiasmata. The homologues connect via axial elements and numerous transverse filaments to form the synaptonemal complex. The synaptonemal complex is a critical component for chromosome pairing, segregation, and recombination. We previously identified a novel germ cell-specific HORMA domain encoding gene, Hormad1, a member of the synaptonemal complex and a mammalian counterpart to the yeast meiotic HORMA domain protein Hop1. Hormad1 is essential for mammalian gametogenesis as knockout male and female mice are infertile. Hormad1 deficient (Hormad1(-/) (-)) testes exhibit meiotic arrest in the early pachytene stage, and synaptonemal complexes cannot be visualized by electron microscopy. Hormad1 deficiency does not affect localization of other synaptonemal complex proteins, SYCP2 and SYCP3, but disrupts homologous chromosome pairing. Double stranded break formation and early recombination events are disrupted in Hormad1(-/) (-) testes and ovaries as shown by the drastic decrease in the γH2AX, DMC1, RAD51, and RPA foci. HORMAD1 co-localizes with γH2AX to the sex body during pachytene. BRCA1, ATR, and γH2AX co-localize to the sex body and participate in meiotic sex chromosome inactivation and transcriptional silencing. Hormad1 deficiency abolishes γH2AX, ATR, and BRCA1 localization to the sex chromosomes and causes transcriptional de-repression on the X chromosome. Unlike testes, Hormad1(-/) (-) ovaries have seemingly normal ovarian folliculogenesis after puberty. However, embryos generated from Hormad1(-/) (-) oocytes are hyper- and hypodiploid at the 2 cell and 8 cell stage, and they arrest at the blastocyst stage. HORMAD1 is therefore a critical component of the synaptonemal complex that affects synapsis, recombination, and meiotic sex chromosome inactivation and transcriptional silencing.

  19. Hormad1 mutation disrupts synaptonemal complex formation, recombination, and chromosome segregation in mammalian meiosis.

    Directory of Open Access Journals (Sweden)

    Yong-Hyun Shin

    2010-11-01

    Full Text Available Meiosis is unique to germ cells and essential for reproduction. During the first meiotic division, homologous chromosomes pair, recombine, and form chiasmata. The homologues connect via axial elements and numerous transverse filaments to form the synaptonemal complex. The synaptonemal complex is a critical component for chromosome pairing, segregation, and recombination. We previously identified a novel germ cell-specific HORMA domain encoding gene, Hormad1, a member of the synaptonemal complex and a mammalian counterpart to the yeast meiotic HORMA domain protein Hop1. Hormad1 is essential for mammalian gametogenesis as knockout male and female mice are infertile. Hormad1 deficient (Hormad1(-/ (- testes exhibit meiotic arrest in the early pachytene stage, and synaptonemal complexes cannot be visualized by electron microscopy. Hormad1 deficiency does not affect localization of other synaptonemal complex proteins, SYCP2 and SYCP3, but disrupts homologous chromosome pairing. Double stranded break formation and early recombination events are disrupted in Hormad1(-/ (- testes and ovaries as shown by the drastic decrease in the γH2AX, DMC1, RAD51, and RPA foci. HORMAD1 co-localizes with γH2AX to the sex body during pachytene. BRCA1, ATR, and γH2AX co-localize to the sex body and participate in meiotic sex chromosome inactivation and transcriptional silencing. Hormad1 deficiency abolishes γH2AX, ATR, and BRCA1 localization to the sex chromosomes and causes transcriptional de-repression on the X chromosome. Unlike testes, Hormad1(-/ (- ovaries have seemingly normal ovarian folliculogenesis after puberty. However, embryos generated from Hormad1(-/ (- oocytes are hyper- and hypodiploid at the 2 cell and 8 cell stage, and they arrest at the blastocyst stage. HORMAD1 is therefore a critical component of the synaptonemal complex that affects synapsis, recombination, and meiotic sex chromosome inactivation and transcriptional silencing.

  20. Zeaxanthin Radical Cation Formation in Minor Light-Harvesting Complexes of Higher Plant Antenna

    Energy Technology Data Exchange (ETDEWEB)

    Avenson, Thomas H.; Ahn, Tae Kyu; Zigmantas, Donatas; Niyogi, Krishna K.; Li, Zhirong; Ballottari, Matteo; Bassi, Roberto; Fleming, Graham R.

    2008-01-31

    Previous work on intact thylakoid membranes showed that transient formation of a zeaxanthin radical cation was correlated with regulation of photosynthetic light-harvesting via energy-dependent quenching. A molecular mechanism for such quenching was proposed to involve charge transfer within a chlorophyll-zeaxanthin heterodimer. Using near infrared (880-1100 nm) transient absorption spectroscopy, we demonstrate that carotenoid (mainly zeaxanthin) radical cation generation occurs solely in isolated minor light-harvesting complexes that bind zeaxanthin, consistent with the engagement of charge transfer quenching therein. We estimated that less than 0.5percent of the isolated minor complexes undergo charge transfer quenching in vitro, whereas the fraction of minor complexes estimated to be engaged in charge transfer quenching in isolated thylakoids was more than 80 times higher. We conclude that minor complexes which bind zeaxanthin are sites of charge transfer quenching in vivo and that they can assume Non-quenching and Quenching conformations, the equilibrium LHC(N)<--> LHC(Q) of which is modulated by the transthylakoid pH gradient, the PsbS protein, and protein-protein interactions.

  1. Ice Complex formation in arctic East Siberia during the MIS3 Interstadial

    Science.gov (United States)

    Wetterich, Sebastian; Tumskoy, Vladimir; Rudaya, Natalia; Andreev, Andrei A.; Opel, Thomas; Meyer, Hanno; Schirrmeister, Lutz; Hüls, Matthias

    2014-01-01

    A continuous 15 m long sequence of Ice Complex permafrost (Yedoma) exposed in a thermo-cirque at the southern coast of Bol'shoy Lyakhovsky Island (New Siberian Archipelago, Dmitry Laptev Strait) was studied to reconstruct past landscape and environmental dynamics. The sequence accumulated during the Marine Isotope Stage 3 (MIS3) Interstadial between >49 and 29 ka BP in an ice-wedge polygon. The frozen deposits were cryolithologically described and sampled on a vertical bluff between two ice wedges. According to sedimentological and geochronological data, the section is subdivided into three units which correlate with environmental conditions of the early, middle, and late MIS3 period. Palynological data support this stratification. The stable isotope signature of texture ice in the polygon structure reflects fractionation due to local freeze-thaw processes, while the signature of an approximately 5 m wide and more than 17 m high ice wedge fits very well into the regional stable-water isotope record. Regional climate dynamics during the MIS3 Interstadial and local landscape conditions of the polygonal patterned ground controlled the Ice Complex formation. The sequence presented here completes previously published MIS3 permafrost records in Northeast Siberia. Late Quaternary stadial-interstadial climate variability in arctic West Beringia is preserved at millennial resolution in the Ice Complex. A MIS3 climate optimum was revealed between 48 and 38 ka BP from the Ice Complex on Bol'shoy Lyakhovsky Island.

  2. Formation of novel transition metal hydride complexes with ninefold hydrogen coordination

    Science.gov (United States)

    Takagi, Shigeyuki; Iijima, Yuki; Sato, Toyoto; Saitoh, Hiroyuki; Ikeda, Kazutaka; Otomo, Toshiya; Miwa, Kazutoshi; Ikeshoji, Tamio; Orimo, Shin-ichi

    2017-01-01

    Ninefold coordination of hydrogen is very rare, and has been observed in two different hydride complexes comprising rhenium and technetium. Herein, based on a theoretical/experimental approach, we present evidence for the formation of ninefold H- coordination hydride complexes of molybdenum ([MoH9]3−), tungsten ([WH9]3−), niobium ([NbH9]4−) and tantalum ([TaH9]4−) in novel complex transition-metal hydrides, Li5MoH11, Li5WH11, Li6NbH11 and Li6TaH11, respectively. All of the synthesized materials are insulated with band gaps of approximately 4 eV, but contain a sufficient amount of hydrogen to cause the H 1s-derived states to reach the Fermi level. Such hydrogen-rich materials might be of interest for high-critical-temperature superconductivity if the gaps close under compression. Furthermore, the hydride complexes exhibit significant rotational motions associated with anharmonic librations at room temperature, which are often discussed in relation to the translational diffusion of cations in alkali-metal dodecahydro-closo-dodecaborates and strongly point to the emergence of a fast lithium conduction even at room temperature. PMID:28287143

  3. Formation of novel transition metal hydride complexes with ninefold hydrogen coordination.

    Science.gov (United States)

    Takagi, Shigeyuki; Iijima, Yuki; Sato, Toyoto; Saitoh, Hiroyuki; Ikeda, Kazutaka; Otomo, Toshiya; Miwa, Kazutoshi; Ikeshoji, Tamio; Orimo, Shin-Ichi

    2017-03-13

    Ninefold coordination of hydrogen is very rare, and has been observed in two different hydride complexes comprising rhenium and technetium. Herein, based on a theoretical/experimental approach, we present evidence for the formation of ninefold H- coordination hydride complexes of molybdenum ([MoH9](3-)), tungsten ([WH9](3-)), niobium ([NbH9](4-)) and tantalum ([TaH9](4-)) in novel complex transition-metal hydrides, Li5MoH11, Li5WH11, Li6NbH11 and Li6TaH11, respectively. All of the synthesized materials are insulated with band gaps of approximately 4 eV, but contain a sufficient amount of hydrogen to cause the H 1s-derived states to reach the Fermi level. Such hydrogen-rich materials might be of interest for high-critical-temperature superconductivity if the gaps close under compression. Furthermore, the hydride complexes exhibit significant rotational motions associated with anharmonic librations at room temperature, which are often discussed in relation to the translational diffusion of cations in alkali-metal dodecahydro-closo-dodecaborates and strongly point to the emergence of a fast lithium conduction even at room temperature.

  4. Platelet-neutrophil complex formation-a detailed in vitro analysis of murine and human blood samples.

    Science.gov (United States)

    Mauler, Maximilian; Seyfert, Julia; Haenel, David; Seeba, Hannah; Guenther, Janine; Stallmann, Daniela; Schoenichen, Claudia; Hilgendorf, Ingo; Bode, Christoph; Ahrens, Ingo; Duerschmied, Daniel

    2016-05-01

    Platelets form complexes with neutrophils during inflammatory processes. These aggregates migrate into affected tissues and also circulate within the organism. Several studies have evaluated platelet-neutrophil complexes as a marker of cardiovascular diseases in human and mouse. Although multiple publications have reported platelet-neutrophil complex counts, we noticed that different methods were used to analyze platelet-neutrophil complex formation, resulting in significant differences, even in baseline values. We established a protocol for platelet-neutrophil complex measurement with flow cytometry in murine and human whole blood samples. In vitro platelet-neutrophil complex formation was stimulated with ADP or PMA. We tested the effect of different sample preparation steps and cytometer settings on platelet-neutrophil complex detection and noticed false-positive counts with increasing acquisition speed. Platelet-neutrophil complex formation depends on platelet P-selectin expression, and antibody blocking of P-selectin consequently prevented ADP-induced platelet-neutrophil complex formation. These findings may help generating more comparable data among different research groups that examine platelet-neutrophil complexes as a marker for cardiovascular disease and novel therapeutic interventions.

  5. Investigation of molecular interactions in the complex formation of tartaric acid derivatives with di(2-ethylhexyl) phosphoric acid

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The molecular interactions in the complex formation of two tartaric acid derivatives with di(2-ethylhexyl) phosphoric acid are investigated. The complex formation with a 1:1 stoichiometry between tartaric acid derivatives and D2EHPA can be obtained through UV-Vis titration, NMR chemical shifts and molecular dynamic simulations. Furthermore, the differences of the two complexes on the binding constants and strength of hydrogen bonds can also be determined. Such research will ideally provide insight into ways of regulating the complex forming properties of tartaric acid derivatives for composing or syn- thesizing new chiral resolving agents.

  6. Investigation of molecular interactions in the complex formation of tartaric acid derivatives with di(2-ethylhexyl) phosphoric acid

    Institute of Scientific and Technical Information of China (English)

    TAN Bin; ZHAI Zheng; LUO GuangSheng; WANG JiaDing

    2008-01-01

    The molecular interactions in the complex formation of two tartaric acid derivatives with di(2-ethylhexyl) phosphoric acid are investigated. The complex formation with a 1:1 stoichiometry between tartaric acid derivatives and D2EHPA can be obtained through UV-Vis titration, NMR chemical shifts and molecular dynamic simulations. Furthermore, the differences of the two complexes on the binding constants and strength of hydrogen bonds can also be determined. Such research will ideally provide insight into ways of regulating the complex forming properties of tartaric acid derivatives for composing or syn-thesizing new chiral resolving agents.

  7. Complex dynamics of osteoclast formation and death in long-term cultures.

    Directory of Open Access Journals (Sweden)

    Timur Akchurin

    Full Text Available BACKGROUND: Osteoclasts, cells responsible for bone resorption, contribute to the development of degenerative, metabolic and neoplastic bone diseases, which are often characterized by persistent changes in bone microenvironment. We aimed to investigate the dynamics of osteoclast formation and death in cultures that considerably exceeded the length of standard protocol and to design a mathematical model describing osteoclastogenesis. METHODOLOGY/PRINCIPAL FINDINGS: RAW 264.7 monocytic cells fuse to form multinucleated osteoclasts upon treatment with pro-resorptive cytokine RANKL. We have found that in long-term experiments (15-26 days, the dynamics of changes in osteoclast numbers was remarkably complex and qualitatively variable in different experiments. Whereas 19 of 46 experiments exhibited single peak of osteoclast formation, in 27 experiments we observed development of successive waves of osteoclast formation and death. Periodic changes in osteoclast numbers were confirmed in long-term cultures of mouse bone marrow cells treated with M-CSF and RANKL. Because the dynamics of changes in osteoclast numbers was found to be largely independent of monocytes, a two-species model of ordinary differential equations describing the changes in osteoclasts and monocytes was ineffective in recapitulating the oscillations in osteoclast numbers. Following experimental observation that medium collected from mature osteoclasts inhibited osteoclastogenesis in fresh cultures, we introduced a third variable, factor f, to describe osteoclast-derived inhibitor. This model allowed us to simulate the oscillatory changes in osteoclasts, which were coupled to oscillatory changes in the factor f, whereas monocytes changed exponentially. Importantly, to achieve the experimentally observed oscillations with increasing amplitude, we also had to assume that osteoclast presence stimulates osteoclast formation. CONCLUSIONS/SIGNIFICANCE: This study identifies the critical

  8. The Scaling Relations and Star Formation Laws of Mini-starburst Complexes

    Science.gov (United States)

    Nguyen-Luong, Quang; Nguyen, Hans V. V.; Motte, Fredérique; Schneider, Nicola; Fujii, Michiko; Louvet, Fabien; Hill, Tracey; Sanhueza, Patricio; Chibueze, James O.; Didelon, Pierre

    2016-12-01

    The scaling relations and star formation laws for molecular cloud complexes (MCCs) in the Milky Way are investigated. MCCs are mostly large (R > 50 pc), massive (˜106 {\\text{}}{M}⊙ ) gravitationally unbound cloud structures. We compare their masses {M}{gas}, mass surface densities {{{Σ }}}{M{gas}}, radii R, velocity dispersions σ, star formation rates (SFRs), and SFR densities {{{Σ }}}{SFR} with those of structures ranging from cores, clumps, and giant molecular clouds, to MCCs, and galaxies, spanning eight orders of magnitudes in size and 13 orders of magnitudes in mass. This results in the following universal relations:σ ˜ {R}0.5,{M}{gas}˜ {R}2,{{{Σ }}}{SFR}˜ {{{Σ }}}{M{gas}}1.5, {SFR}˜ {{M}{gas}}0.9, {and} {SFR}˜ {σ }2.7. Variations in the slopes and coefficients of these relations are found at individual scales, signifying different physics acting at different scales. Additionally, there are breaks at the MCC scale in the σ {--}R relation and between starburst and normal star-forming objects in the {SFR}{--}{M}{gas} and {{{Σ }}}{SFR}-{{{Σ }}}{{{M}}{gas}} relations. Therefore, we propose to use the Schmidt-Kennicutt diagram to distinguish starburst from normal star-forming structures by applying a {{{Σ }}}{M{gas}} threshold of ˜100 {\\text{}}{M}⊙ pc-2 and a {{{Σ }}}{SFR} threshold of 1 {\\text{}}{M}⊙ yr-1 kpc-2. Mini-starburst complexes are gravitationally unbound MCCs that have enhanced {{{Σ }}}{SFR} (>1 {\\text{}}{M}⊙ yr-1 kpc-2), probably caused by dynamic events such as radiation pressure, colliding flows, or spiral arm gravitational instability. Because of dynamical evolution, gravitational boundedness does not play a significant role in regulating the star formation activity of MCCs, especially the mini-starburst complexes, which leads to the dynamical formation of massive stars and clusters. We emphasize the importance of understanding mini-starbursts in investigating the physics of starburst galaxies.

  9. Studies on chalcone derivatives: complex formation, thermal behavior, stability constant and antioxidant activity.

    Science.gov (United States)

    El-Sayed, Yusif S; Gaber, M

    2015-02-25

    The chalcone 3-[4'-dimethylaminophenyl]-1-(2-pyridyl) prop-2-en-1-one (DMAPP) and 3-(4'-diethylaminophenyl)-1-(2-pyridinyl) prop-2-en-1-one abbreviated as DEAPP have been synthesized and characterized with IR, (1)H NMR, (13)C NMR spectroscopic techniques as described previously (El-Daly et al., 2008; Gaber et al., 2009; El-Sayed, 2013). By using UV visible spectroscopy method the mole fraction ratio for copper with DMAPP and DEAPP complexes were determined and it was found to be 1:1. The stability constants of this complex have been determined by Job's method. The stability constant (Kf) of copper with DMAPP and DEAPP complexes in universal buffer pH=3.2 was determined to be 9.9×10(4) and 5.2×10(4) respectively. The effect of Cu(II) ion on the emission spectrum of the free chalcone is also assigned. Adherence to Beer's law and Ringbom optimum concentration ranges are determined. The thermal decomposition of the metal complexes is studied by TGA technique. The kinetic parameters like activation energy, pre-exponential factor and entropy of activation are estimated. The structure of complexes was energetically optimized through molecular mechanics applying MM(+) force field coupled with molecular dynamics simulation. The bond lengths and bond angles have been calculated to confirm the geometry of the ligands and their Cu(II) complexes. The mode of interaction of the chalcone to copper nanoparticles was studied. The apparent association constants of the colloidal copper nanoparticles:chalcone complexes in solution were evaluated using the spectral method and compared with the formation constant of the Cu(II) chalcone complexes. Antioxidant activity of these chalcones was evaluated by using 1,1'-diphenyl-2-picrylhydrazyl (DPPH) radicals scavenging method, which showed that the antioxidant activity of DMAPP has higher value than the DEAPP. Semi-empirical study results showed that DMAPP have higher dipole moment than DEAPP.

  10. Studies on chalcone derivatives: Complex formation, thermal behavior, stability constant and antioxidant activity

    Science.gov (United States)

    El-Sayed, Yusif S.; Gaber, M.

    2015-02-01

    The chalcone 3-[4‧-dimethylaminophenyl]-1-(2-pyridyl) prop-2-en-1-one (DMAPP) and 3-(4‧-diethylaminophenyl)-1-(2-pyridinyl) prop-2-en-1-one abbreviated as DEAPP have been synthesized and characterized with IR, 1H NMR, 13C NMR spectroscopic techniques as described previously (El-Daly et al., 2008; Gaber et al., 2009; El-Sayed, 2013). By using UV visible spectroscopy method the mole fraction ratio for copper with DMAPP and DEAPP complexes were determined and it was found to be 1:1. The stability constants of this complex have been determined by Job's method. The stability constant (Kf) of copper with DMAPP and DEAPP complexes in universal buffer pH = 3.2 was determined to be 9.9 × 104 and 5.2 × 104 respectively. The effect of Cu(II) ion on the emission spectrum of the free chalcone is also assigned. Adherence to Beer's law and Ringbom optimum concentration ranges are determined. The thermal decomposition of the metal complexes is studied by TGA technique. The kinetic parameters like activation energy, pre-exponential factor and entropy of activation are estimated. The structure of complexes was energetically optimized through molecular mechanics applying MM+ force field coupled with molecular dynamics simulation. The bond lengths and bond angles have been calculated to confirm the geometry of the ligands and their Cu(II) complexes. The mode of interaction of the chalcone to copper nanoparticles was studied. The apparent association constants of the colloidal copper nanoparticles:chalcone complexes in solution were evaluated using the spectral method and compared with the formation constant of the Cu(II) chalcone complexes. Antioxidant activity of these chalcones was evaluated by using 1,1‧-diphenyl-2-picrylhydrazyl (DPPHrad) radicals scavenging method, which showed that the antioxidant activity of DMAPP has higher value than the DEAPP. Semi-empirical study results showed that DMAPP have higher dipole moment than DEAPP [1].

  11. Quantum chemical insights in energy dissipation and carotenoid radical cation formation in light harvesting complexes.

    Science.gov (United States)

    Wormit, Michael; Dreuw, Andreas

    2007-06-21

    Light harvesting complexes (LHCs) have been identified in all photosynthetic organisms. To understand their function in light harvesting and energy dissipation, detailed knowledge about possible excitation energy transfer (EET) and electron transfer (ET) processes in these pigment proteins is of prime importance. This again requires the study of electronically excited states of the involved pigment molecules, in LHCs of chlorophylls and carotenoids. This paper represents a critical review of recent quantum chemical calculations on EET and ET processes between pigment pairs relevant for the major LHCs of green plants (LHC-II) and of purple bacteria (LH2). The theoretical methodology for a meaningful investigation of such processes is described in detail, and benefits and limitations of standard methods are discussed. The current status of excited state calculations on chlorophylls and carotenoids is outlined. It is focused on the possibility of EET and ET in the context of chlorophyll fluorescence quenching in LHC-II and carotenoid radical cation formation in LH2. In the context of non-photochemical quenching of green plants, it is shown that replacement of the carotenoid violaxanthin by zeaxanthin in its binding pocket of LHC-II can not result in efficient quenching. In LH2, our computational results give strong evidence that the S(1) states of the carotenoids are involved in carotenoid cation formation. By comparison of theoretical findings with recent experimental data, a general mechanism for carotenoid radical cation formation is suggested.

  12. Gastrointestinal migrating motor complex during early stage of cholesterol gallstone formation in guinea pigs

    Institute of Scientific and Technical Information of China (English)

    Wang Ling; Bai Wenyuan; Ma Yongzhi; Gu Yong

    2008-01-01

    Objective: To determine the changes of gastrointestinal migrating motor complex (MMC) during the early stage of cholesterol gallstone formation. Methods: Totally 45 healthy adult guinea pigs were randomly and equally divided into 3 groups, that is, normal control, group B (1% cholesterol diet for 2 weeks) and group C (1% cholesterol diet for 4 weeks). Three pairs of silver electrodes were inserted into the gastric antrum, duodenum and jejunum of every animal respectively. Record of gastrointestinal MMC of these guinea pigs were recorded and analyzed.Gallbladder bile was taken to detect the formation of cholesterol gallstone. Results: There were only 29 guineapigs living. The MMC cycle time and the duration of phase Ⅱ were prolonged significantly and gradually compared with the control group (P<0.01), but the duration of phase Ⅲ became significantly and gradually shorter. Conclusion:During the early stage of cholesterol gallstone formation, the MMC cycle time and the duration of phase Ⅱ are prolonged and the duration of phase Ⅲ is shortened

  13. Statistical considerations on the formation of circular photosynthetic light-harvesting complexes from Rhodopseudomonas palustris.

    Science.gov (United States)

    Taniguchi, Masahiko; Henry, Sarah; Cogdell, Richard J; Lindsey, Jonathan S

    2014-07-01

    Depending on growth conditions, some species of purple photosynthetic bacteria contain peripheral light-harvesting (LH2) complexes that are heterogeneous owing to the presence of different protomers (containing different αβ-apoproteins). Recent spectroscopic studies of Rhodopseudomonas palustris grown under low-light conditions suggest the presence of a C 3-symmetric LH2 nonamer comprised of two distinct protomers. The software program Cyclaplex, which enables generation and data-mining of virtual libraries of molecular rings formed upon combinatorial reactions, has been used to delineate the possible number and type of distinct nonamers as a function of numbers of distinct protomers. The yield of the C 3-symmetric nonamer from two protomers (A and B in varying ratios) has been studied under the following conditions: (1) statistical, (2) enriched (preclusion of the B-B sequence), and (3) seeded (pre-formation of an A-B-A block). The yield of C 3-symmetric nonamer is at most 0.98 % under statistical conditions versus 5.6 % under enriched conditions, and can be dominant under conditions of pre-seeding with an A-B-A block. In summary, the formation of any one specific nonamer even from only two protomers is unlikely on statistical grounds but must stem from enhanced free energy of formation or a directed assembly process by as-yet unknown factors.

  14. Formation of complex organic molecules in cold objects: the role of gas-phase reactions

    Science.gov (United States)

    Balucani, Nadia; Ceccarelli, Cecilia; Taquet, Vianney

    2015-04-01

    While astrochemical models are successful in reproducing many of the observed interstellar species, they have been struggling to explain the observed abundances of complex organic molecules. Current models tend to privilege grain surface over gas-phase chemistry in their formation. One key assumption of those models is that radicals trapped in the grain mantles gain mobility and react on lukewarm ( ≳ 30 K) dust grains. Thus, the recent detections of methyl formate (MF) and dimethyl ether (DME) in cold objects represent a challenge and may clarify the respective role of grain-surface and gas-phase chemistry. We propose here a new model to form DME and MF with gas-phase reactions in cold environments, where DME is the precursor of MF via an efficient reaction overlooked by previous models. Furthermore, methoxy, a precursor of DME, is also synthesized in the gas phase from methanol, which is desorbed by a non-thermal process from the ices. Our new model reproduces fairly well the observations towards L1544. It also explains, in a natural way, the observed correlation between DME and MF. We conclude that gas-phase reactions are major actors in the formation of MF, DME and methoxy in cold gas. This challenges the exclusive role of grain-surface chemistry and favours a combined grain-gas chemistry.

  15. Dust, Gas, and Star Formation in the MBM 18--19 High-Latitude Cloud Complex

    Science.gov (United States)

    Larson, Kristen A.; Reed, Cyrus M.

    Projected on the plane of the sky, the MBM 19 molecular cloud extends from the MBM 18 high-latitude cloud toward the Taurus star-forming regions. We present a new CO(J = 1--0) map of MBM 19 that shows clumpy emission with line intensities above 3 K in some regions despite low, relatively smooth 100 micron emission and modest visual extinction. This map complements data that show extremely high polarization efficiency of dust aligned along the bridge axis and low values of the ratio of total-to-selective extinction throughout the complex. In addition, several ongoing searches for spectral signatures of young stars have found evidence for star formation associated with MBM 18--19. We discuss variation in the molecular gas fraction and dust-to-gas ratio estimates, as well as the implications all these data have for understanding star formation in the region. Results of this study and others like it will provide insight into dust and gas of the translucent interstellar medium and star formation at high galactic latitude. This research was supported by the American Astronomical Society's Small Research Grant Program.

  16. A MULTI-WAVELENGTH STUDY OF STAR FORMATION ACTIVITY IN THE S235 COMPLEX

    Energy Technology Data Exchange (ETDEWEB)

    Dewangan, L. K.; Luna, A.; Mayya, Y. D. [Instituto Nacional de Astrofísica, Óptica y Electrónica, Luis Enrique Erro # 1, Tonantzintla, Puebla, C.P. 72840, México (Mexico); Ojha, D. K.; Ninan, J. P.; Mallick, K. K. [Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005 (India); Anandarao, B. G., E-mail: lokeshd@prl.res.in [Physical Research Laboratory, Navrangpura, Ahmedabad—380 009 (India)

    2016-03-01

    We have carried out an extensive multi-wavelength study to investigate the star formation process in the S235 complex. The S235 complex has a spherelike shell appearance at wavelengths longer than 2 μm and harbors an O9.5V type star approximately at its center. A near-infrared extinction map of the complex traces eight subregions (having A{sub V} > 8 mag), and five of them appear to be distributed in an almost regularly spaced manner along the spherelike shell surrounding the ionized emission. This picture is also supported by the integrated {sup 12}CO and {sup 13}CO intensity maps and by Bolocam 1.1 mm continuum emission. The position–velocity analysis of CO reveals an almost semi-ringlike structure, suggesting an expanding H ii region. We find that the Bolocam clump masses increase as we move away from the location of the ionizing star. This correlation is seen only for those clumps that are distributed near the edges of the shell. Photometric analysis reveals 435 young stellar objects (YSOs), 59% of which are found in clusters. Six subregions (including five located near the edges of the shell) are very well correlated with the dust clumps, CO gas, and YSOs. The average values of Mach numbers derived using NH{sub 3} data for three (East 1, East 2, and Central E) out of these six subregions are 2.9, 2.3, and 2.9, indicating these subregions are supersonic. The molecular outflows are detected in these three subregions, further confirming the ongoing star formation activity. Together, all these results are interpreted as observational evidence of positive feedback of a massive star.

  17. A defined peptide that inhibits the formation of the glycoprotein IIb and IIIa complex.

    Science.gov (United States)

    Chiang, Thomas M; Zhu, Jiaqian

    2005-01-01

    Collagen-platelet interaction plays an important role in hemostasis and pathological thrombosis. The proposed mechanism of the interaction was the activation of platelets-->releasing of contents from granules-->aggregation. The common end point is the platelets and fibrin aggregates. Platelet glycoprotein (GP) IIb/IIIa (the alphaIIbbeta3 integrin) complexes serve as a receptor for the binding of fibrinogen to form firmed aggregates. Blockading of GP IIb/IIIa has been proposed to prevent platelet aggregation independent of the substance(s) responsible for activating the platelets. The development of various forms of GP IIb/IIIa inhibitor has resulted in the inhibition of platelet aggregation, although studies of alphaIIbbeta3 receptor function and various GP IIb/IIIa inhibitors have demonstrated the potential for these agents to produce effects on other aspects of platelet function as well as having nonplatelet effects. This study investigated platelet inhibition provided by blocking the GP IIb/IIIa complex formation by using a peptide derived from the GP IIIa molecule. The peptide inhibits both types I and III collagen-induced platelet aggregation in a dose-dependent manner. The defined peptide interferes with the formation of the GP IIb/IIIa complex by inhibiting the binding of FITC-PAC-1 onto ADP-, type I collagen-, and type III collagen-activated platelets. However, P-selectin secretion is not affected by the peptide. In addition, the peptide is not interfering with the binding of FITC-PAC-1 to platelets that were preincubated with indomethacin. Results from this study may suggest that the defined peptide is an effective agent to block the interaction of types I and III collagen with platelets.

  18. The formation of ethylene glycol and other complex organic molecules in star-forming regions

    CERN Document Server

    Rivilla, V M; Cesaroni, R; Fontani, F; Codella, C; Zhang, Q

    2016-01-01

    We study the molecular abundance and spatial distribution of the simplest sugar alcohol, ethylene glycol (EG), the simplest sugar glycoladehyde (GA), and other chemically related complex organic species towards the massive star-forming region G31.41+0.31. We have analyzed multiple single dish and interferometric data, and obtained excitation temperatures and column densities using an LTE analysis. We have reported for the first time the presence of EG towards G31.41+0.31, and we have also detected multiple transitions of other complex organic molecules such as GA, methyl formate (MF), dimethyl ether (DME) and ethanol (ET). The high angular resolution images show that the EG emission is very compact, peaking towards the maximum of the continuum. These observations suggest that low abundance complex organic molecules, like EG or GA, are good probes of the gas located closer to the forming stars. Our analysis confirms that EG is more abundant than GA in G31.41+0.31, as previously observed in other interstellar r...

  19. Formation of a porphyrin pi-cation radical in the fluoride complex of horseradish peroxidase.

    Science.gov (United States)

    Farhangrazi, Z S; Sinclair, R; Powers, L; Yamazaki, I

    1995-11-21

    Horseradish peroxidase (HRP) was oxidized by IrCl6(2-) to a mixture of compounds I and II, the rate of oxidation and the ratio of the mixture being greatly affected by pH (Hayashi & Yamazaki, 1979). Oxidation of HRP by IrCl6(2-) in the presence of fluoride was significantly accelerated. This resulted in the formation of a new compound which is a ferric fluoride complex containing a porphyrin pi-cation radical. The spectrum of the new compound showed a decreased absorption band in the Soret region and a broad band at 570 nm; which was converted to that of the original ferric fluoride complex by addition of ascorbate or hydroquinone. Addition of cyanide slowed down the oxidation of HRP by IrCl6(2-), and the oxidation product was the same as that obtained in the absence of cyanide. Compound I was formed when H2O2 was added to HRP in the presence of fluoride or cyanide. The one-electron reduction potential (Eo') of the oxidized HRP-fluoride complex was measured at several pH values, the Eo' value at pH 7 being 861 +/- 4 mV. The ratio of delta Eo' to delta pH was 49 mV/pH unit.

  20. Temperature and dose dependence of defect complex formation with ion implanted Mn/Fe in ZnO

    CERN Document Server

    Mølholt, T E; Gunnlaugsson, H P; Bharuth-Ram, K; Fanciulli, M; Gíslason, H P; Johnston, K; Kobayashi, Y; Langouche, G; Masenda, H; Naidoo, D; Ólafsson, S; Sielemann, R; Weyer, G

    2009-01-01

    57Fe Mössbauer spectroscopy following ion implantation of radioactive 57Mn+ ( T1/2=85.4 s) has been applied to study the formation of Fe/Mn implantation-induced defects in ZnO at temperatures between 319 and 390 K. The formation of ferric iron–vacancy complexes is found to depend strongly on the implanted dose and to be faster and more efficient at higher temperatures. The results at these temperatures suggest the mobility of the Zn vacancy, together with vacancy trapping at the substitutional Mn/Fe impurities are responsible for the formation of Fe–VZn complexes

  1. Formation, Isolation and Characterization of a New Ruthenium Complex in Reaction of Acetone Masked Terminal Alkynone with Transfer Hydrogenation Catalyst

    Institute of Scientific and Technical Information of China (English)

    郭敏捷; 李到; 孙延辉; 成江; 张兆国

    2004-01-01

    Reaction of [1S,2S-(Ts-diphen)Ru(Ⅱ)(p-cymene)] (1S,2S-Ts-diphen= 1S,2S-N-tosyl-1,2-diphenylethylenediamine) and 2-hydroxy-2-methyl-non-3-yn-5-one under transfer hydrogenation condition gave a ruthenium complex bearing a 2,5-dihydrofuran moiety. The complex was characterized and a possible mechanism for the formation of the complex was proposed.

  2. Thermodynamics of Complex Sulfide Inclusion Formation in Ca-Treated Al-Killed Structural Steel

    Science.gov (United States)

    Guo, Yin-tao; He, Sheng-ping; Chen, Gu-jun; Wang, Qian

    2016-08-01

    Controlling the morphology of the sulfide inclusion is of vital importance in enhancing the properties of structural steel. Long strip-shaped sulfides in hot-rolled steel can spherize when, instead of the inclusion of pure single-phase MnS, the guest is a complex sulfide, such as an oxide-sulfide duplex and a solid-solution sulfide particle. In this study, the inclusions in a commercial rolled structural steel were investigated. Spherical and elongated oxide-sulfide duplex as well as single-phase (Mn,Ca)S solid solution inclusions were observed in the steel. A thermodynamic equilibrium between the oxide and sulfide inclusions was proposed to understand the oxide-sulfide duplex inclusion formation. Based on the equilibrium solidification principle, thermodynamic discussions on inclusion precipitation during the solidification process were performed for both general and resulfurized structural steel. The predicted results of the present study agreed well with the experimental ones.

  3. Formation of Large Polysulfide Complexes during the Lithium-Sulfur Battery Discharge

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Bin [Vanderbilt University, Nashville; Alhassan, Saeed M. [The Petroleum Institute; Pantelides, Sokrates T [ORNL

    2014-01-01

    Sulfur cathodes have much larger capacities than transition-metal-oxide cathodes used in commercial lithium-ion batteries but suffer from unsatisfactory capacity retention and long-term cyclability. Capacity degradation originates from soluble lithium polysulfides gradually diffusing into the electrolyte. Understanding of the formation and dynamics of soluble polysulfides during the discharging process at the atomic level remains elusive, which limits further development of lithium-sulfur (Li-S) batteries. Here we report first-principles molecular dynamics simulations and density functional calculations, through which the discharging products of Li-S batteries are studied. We find that, in addition to simple Li2Sn (1 n 8) clusters generated from single cyclooctasulfur (S8) rings, large Li-S clusters form by collectively coupling several different rings to minimize the total energy. At high lithium concentration, a Li-S network forms at the sulfur surfaces. The results can explain the formation of the soluble Li-S complex, such as Li2S8, Li2S6, and Li2S4, and the insoluble Li2S2 and Li2S structures. In addition, we show that the presence of oxygen impurities in graphene, particularly oxygen atoms bonded to vacancies and edges, may stabilize the lithium polysulfides that may otherwise diffuse into the electrolyte.

  4. Formation of Large Polysulfide Complexes during the Lithium-Sulfur Battery Discharge

    Science.gov (United States)

    Wang, Bin; Alhassan, Saeed M.; Pantelides, Sokrates T.

    2014-09-01

    Sulfur cathodes have much larger capacities than transition-metal-oxide cathodes used in commercial lithium-ion batteries but suffer from unsatisfactory capacity retention and long-term cyclability. Capacity degradation originates from soluble lithium polysulfides gradually diffusing into the electrolyte. Understanding of the formation and dynamics of soluble polysulfides during the discharging process at the atomic level remains elusive, which limits further development of lithium-sulfur (Li-S) batteries. Here we report first-principles molecular dynamics simulations and density functional calculations, through which the discharging products of Li-S batteries are studied. We find that, in addition to simple Li2Sn (1≤n ≤8) clusters generated from single cyclooctasulfur (S8) rings, large Li-S clusters form by collectively coupling several different rings to minimize the total energy. At high lithium concentration, a Li-S network forms at the sulfur surfaces. The results can explain the formation of the soluble Li-S complex, such as Li2S8, Li2S6, and Li2S4, and the insoluble Li2S2 and Li2S structures. In addition, we show that the presence of oxygen impurities in graphene, particularly oxygen atoms bonded to vacancies and edges, may stabilize the lithium polysulfides that may otherwise diffuse into the electrolyte.

  5. Formation of complex organic molecules in cold objects: the role of gas phase reactions

    CERN Document Server

    Balucani, Nadia; Taquet, Vianney

    2015-01-01

    While astrochemical models are successful in reproducing many of the observed interstellar species, they have been struggling to explain the observed abundances of complex organic molecules. Current models tend to privilege grain surface over gas phase chemistry in their formation. One key assumption of those models is that radicals trapped in the grain mantles gain mobility and react on lukewarm (>30 K) dust grains. Thus, the recent detections of methyl formate (MF) and dimethyl ether (DME) in cold objects represent a challenge and may clarify the respective role of grain surface and gas phase chemistry. We propose here a new model to form DME and MF with gas phase reactions in cold environments, where DME is the precursor of MF via an efficient reaction overlooked by previous models. Furthermore, methoxy, a precursor of DME, is also synthetized in the gas phase from methanol, which is desorbed by a non-thermal process from the ices. Our new model reproduces fairy well the observations towards L1544. It also...

  6. P31comet, a member of the synaptonemal complex, participates in meiotic DSB formation in rice.

    Science.gov (United States)

    Ji, Jianhui; Tang, Ding; Shen, Yi; Xue, Zhihui; Wang, Hongjun; Shi, Wenqing; Zhang, Chao; Du, Guijie; Li, Yafei; Cheng, Zhukuan

    2016-09-20

    The human mitotic arrest-deficient 2 (Mad2) binding protein p31(comet) participates in the spindle checkpoint and coordinates cell cycle events in mitosis although its function in meiosis remains unknown in all organisms. Here, we reveal P31(comet) as a synaptonemal complex (SC) protein in rice (Oryza sativa L.). In p31(comet), homologous pairing and synapsis are eliminated, leading to the homologous nondisjunction and complete sterility. The failure in loading of histone H2AX phosphorylation (γH2AX) in p31(comet), together with the suppressed chromosome fragmentation in rice completion of meiotic recombination 1 (com1) p31(comet) and radiation sensitive 51c (rad51c) p31(comet) double mutants, indicates that P31(comet) plays an essential role in double-strand break (DSB) formation. Interestingly, the dynamic colocalization pattern between P31(comet) and ZEP1 (a transverse filament protein of SC) by immunostaining, as well as the interaction between P31(comet) and CENTRAL REGION COMPONENT 1 (CRC1) in yeast two-hybrid assays, suggests possible involvement of P31(comet) in SC installation. Together, these data indicate that P31(comet) plays a key role in DSB formation and SC installation, mainly through its cooperation with CRC1.

  7. Unraveling the complexities of circadian and sleep interactions with memory formation through invertebrate research

    Directory of Open Access Journals (Sweden)

    Maximilian eMichel

    2014-08-01

    Full Text Available Across phylogeny, the endogenous biological clock has been recognized as providing adaptive advantages to organisms through coordination of physiological and behavioral processes. Recent research has emphasized the role of circadian modulation of memory in generating peaks and troughs in cognitive performance. The circadian clock along with homeostatic processes also regulates sleep, which itself impacts the formation and consolidation of memory. Thus, the circadian clock, sleep and memory form a triad with ongoing dynamic interactions. With technological advances and the development of a global 24/7 society, understanding the mechanisms underlying these connections becomes pivotal for development of therapeutic treatments for memory disorders and to address issues in cognitive performance arising from non-traditional work schedules. Invertebrate models, such as Drosophila melanogaster and the mollusks Aplysia and Lymnaea, have proven invaluable tools for identification of highly conserved molecular processes in memory. Recent research from invertebrate systems has outlined the influence of sleep and the circadian clock upon synaptic plasticity. In this review, we discuss the effects of the circadian clock and sleep on memory formation in invertebrates drawing attention to the potential of in vivo and in vitro approaches that harness the power of simple invertebrate systems to correlate individual cellular processes with complex behaviors. In conclusion, this review highlights how studies in invertebrates with relatively simple nervous systems can provide mechanistic insights into corresponding behaviors in higher organisms and can be used to outline possible therapeutic options to guide further targeted inquiry.

  8. Unraveling the complexities of circadian and sleep interactions with memory formation through invertebrate research.

    Science.gov (United States)

    Michel, Maximilian; Lyons, Lisa C

    2014-01-01

    Across phylogeny, the endogenous biological clock has been recognized as providing adaptive advantages to organisms through coordination of physiological and behavioral processes. Recent research has emphasized the role of circadian modulation of memory in generating peaks and troughs in cognitive performance. The circadian clock along with homeostatic processes also regulates sleep, which itself impacts the formation and consolidation of memory. Thus, the circadian clock, sleep and memory form a triad with ongoing dynamic interactions. With technological advances and the development of a global 24/7 society, understanding the mechanisms underlying these connections becomes pivotal for development of therapeutic treatments for memory disorders and to address issues in cognitive performance arising from non-traditional work schedules. Invertebrate models, such as Drosophila melanogaster and the mollusks Aplysia and Lymnaea, have proven invaluable tools for identification of highly conserved molecular processes in memory. Recent research from invertebrate systems has outlined the influence of sleep and the circadian clock upon synaptic plasticity. In this review, we discuss the effects of the circadian clock and sleep on memory formation in invertebrates drawing attention to the potential of in vivo and in vitro approaches that harness the power of simple invertebrate systems to correlate individual cellular processes with complex behaviors. In conclusion, this review highlights how studies in invertebrates with relatively simple nervous systems can provide mechanistic insights into corresponding behaviors in higher organisms and can be used to outline possible therapeutic options to guide further targeted inquiry.

  9. Nucleoporin translocated promoter region (Tpr) associates with dynein complex, preventing chromosome lagging formation during mitosis.

    Science.gov (United States)

    Nakano, Hiroshi; Funasaka, Tatsuyoshi; Hashizume, Chieko; Wong, Richard W

    2010-04-01

    Gain or loss of whole chromosomes is often observed in cancer cells and is thought to be due to aberrant chromosome segregation during mitosis. Proper chromosome segregation depends on a faithful interaction between spindle microtubules and kinetochores. Several components of the nuclear pore complex/nucleoporins play critical roles in orchestrating the rapid remodeling events that occur during mitosis. Our recent studies revealed that the nucleoporin, Rae1, plays critical roles in maintaining spindle bipolarity. Here, we show association of another nucleoporin, termed Tpr (translocated promoter region), with the molecular motors dynein and dynactin, which both orchestrate with the spindle checkpoints Mad1 and Mad2 during cell division. Overexpression of Tpr enhanced multinucleated cell formation. RNA interference-mediated knockdown of Tpr caused a severe lagging chromosome phenotype and disrupted spindle checkpoint proteins expression and localization. Next, we performed a series of rescue and dominant negative experiments to confirm that Tpr orchestrates proper chromosome segregation through interaction with dynein light chain. Our data indicate that Tpr functions as a spatial and temporal regulator of spindle checkpoints, ensuring the efficient recruitment of checkpoint proteins to the molecular motor dynein to promote proper anaphase formation.

  10. Generalized additive models reveal the intrinsic complexity of wood formation dynamics.

    Science.gov (United States)

    Cuny, Henri E; Rathgeber, Cyrille B K; Kiessé, Tristan Senga; Hartmann, Felix P; Barbeito, Ignacio; Fournier, Meriem

    2013-04-01

    The intra-annual dynamics of wood formation, which involves the passage of newly produced cells through three successive differentiation phases (division, enlargement, and wall thickening) to reach the final functional mature state, has traditionally been described in conifers as three delayed bell-shaped curves followed by an S-shaped curve. Here the classical view represented by the 'Gompertz function (GF) approach' was challenged using two novel approaches based on parametric generalized linear models (GLMs) and 'data-driven' generalized additive models (GAMs). These three approaches (GFs, GLMs, and GAMs) were used to describe seasonal changes in cell numbers in each of the xylem differentiation phases and to calculate the timing of cell development in three conifer species [Picea abies (L.), Pinus sylvestris L., and Abies alba Mill.]. GAMs outperformed GFs and GLMs in describing intra-annual wood formation dynamics, showing two left-skewed bell-shaped curves for division and enlargement, and a right-skewed bimodal curve for thickening. Cell residence times progressively decreased through the season for enlargement, whilst increasing late but rapidly for thickening. These patterns match changes in cell anatomical features within a tree ring, which allows the separation of earlywood and latewood into two distinct cell populations. A novel statistical approach is presented which renews our understanding of xylogenesis, a dynamic biological process in which the rate of cell production interplays with cell residence times in each developmental phase to create complex seasonal patterns.

  11. Enhanced conformational sampling to visualize a free-energy landscape of protein complex formation.

    Science.gov (United States)

    Iida, Shinji; Nakamura, Haruki; Higo, Junichi

    2016-06-15

    We introduce various, recently developed, generalized ensemble methods, which are useful to sample various molecular configurations emerging in the process of protein-protein or protein-ligand binding. The methods introduced here are those that have been or will be applied to biomolecular binding, where the biomolecules are treated as flexible molecules expressed by an all-atom model in an explicit solvent. Sampling produces an ensemble of conformations (snapshots) that are thermodynamically probable at room temperature. Then, projection of those conformations to an abstract low-dimensional space generates a free-energy landscape. As an example, we show a landscape of homo-dimer formation of an endothelin-1-like molecule computed using a generalized ensemble method. The lowest free-energy cluster at room temperature coincided precisely with the experimentally determined complex structure. Two minor clusters were also found in the landscape, which were largely different from the native complex form. Although those clusters were isolated at room temperature, with rising temperature a pathway emerged linking the lowest and second-lowest free-energy clusters, and a further temperature increment connected all the clusters. This exemplifies that the generalized ensemble method is a powerful tool for computing the free-energy landscape, by which one can discuss the thermodynamic stability of clusters and the temperature dependence of the cluster networks.

  12. Protein complex formation and intranuclear dynamics of NAC1 in cancer cells.

    Science.gov (United States)

    Nakayama, Naomi; Kato, Hiroaki; Sakashita, Gyosuke; Nariai, Yuko; Nakayama, Kentaro; Kyo, Satoru; Urano, Takeshi

    2016-09-15

    Nucleus accumbens-associated protein 1 (NAC1) is a cancer-related transcription regulator protein that is also involved in the pluripotency and differentiation of embryonic stem cells. NAC1 is overexpressed in various carcinomas including ovarian, cervical, breast, and pancreatic carcinomas. NAC1 knock-down was previously shown to result in the apoptosis of ovarian cancer cell lines and to rescue their sensitivity to chemotherapy, suggesting that NAC1 may be a potential therapeutic target, but protein complex formation and the dynamics of intranuclear NAC1 in cancer cells remain poorly understood. In this study, analysis of HeLa cell lysates by fast protein liquid chromatography (FPLC) on a sizing column showed that the NAC1 peak corresponded to an apparent molecular mass of 300-500 kDa, which is larger than the estimated molecular mass (58 kDa) of the protein. Furthermore, live cell photobleaching analyses with green fluorescent protein (GFP)-fused NAC1 proteins revealed the intranuclear dynamics of NAC1. Collectively our results demonstrate that NAC1 forms a protein complex to function as a transcriptional regulator in cancer cells.

  13. Spectrophotometric Determination of Gemifloxacin Mesylate in Pharmaceutical Formulations Through Ion-Pair Complex Formation

    Directory of Open Access Journals (Sweden)

    Marothu Vamsi Krishna

    2008-01-01

    Full Text Available Four simple and sensitive ion-pairing spectrophotometric methods have been described for the assay of gemifloxacin mesylate (GFX either in pure form or in pharmaceutical formulations. The developed methods involve formation of colored chloroform extractable ion-pair complexes of the drug with safranin O (SFN O and methylene blue (MB in basic medium; Napthol blue 12BR (NB 12BR and azocaramine G (AG in acidic medium. The extracted complexes showed absorbance maxima at 525, 650, 620 and 540 nm for SFN O, MB, NB 12BR and AG, respectively.Beer's law is obeyed in the concentration ranges 3-15, 4-20, 2-10 and 2-10 μg/mL with molar absorptivity of 2.81 × 104, 2.20 x 104, 4.02 × 104 and 4.15 × 104 L mole−1 cm−1 and relative standard deviation of 0.077, 0.104, 0.080 and 0.103% for SFN O, MB, NB 12BR and AG, respectively. These methods have been successfully applied for the assay of drug in pharmaceutical formulations. No interference was observed from common pharmaceutical adjuvants. Results of analysis were validated statistically and through recovery studies.

  14. A multi-wavelength study of star formation activity in the S235 complex

    CERN Document Server

    Dewangan, L K; Luna, A; Anandarao, B G; Ninan, J P; Mallick, K K; Mayya, Y D

    2016-01-01

    We have carried out an extensive multi-wavelength study to investigate the star formation process in the S235 complex. The S235 complex has a sphere-like shell appearance at wavelengths longer than 2 $\\mu$m and harbors an O9.5V type star approximately at its center. Near-infrared extinction map traces eight subregions (having A$_{V}$ $>$ 8 mag), and five of them appear to be distributed in an almost regularly spaced manner along the sphere-like shell surrounding the ionized emission. This picture is also supported by the integrated $^{12}$CO and $^{13}$CO intensity maps and by Bolocam 1.1 mm continuum emission. The position-velocity analysis of CO reveals an almost semi-ring like structure, suggesting an expanding H\\,{\\sc ii} region. We find that the Bolocam clump masses increase as we move away from the location of the ionizing star. This correlation is seen only for those clumps which are distributed near the edges of the shell. Photometric analysis reveals 435 young stellar objects (YSOs), 59\\% of which ar...

  15. Interactions between plutonism and detachments during metamorphic core complex formation, Serifos Island (Cyclades, Greece)

    Science.gov (United States)

    Rabillard, Aurélien; Arbaret, Laurent; Jolivet, Laurent; Le Breton, Nicole; Gumiaux, Charles; Augier, Romain; Grasemann, Bernhard

    2015-06-01

    In order to better understand the interactions between plutonic activity and strain localization during metamorphic core complex formation, the Miocene granodioritic pluton of Serifos (Cyclades, Greece) is studied. This pluton (11.6-9.5 Ma) intruded the Cycladic Blueschists during thinning of the Aegean domain along a system of low-angle normal faults belonging to the south dipping West Cycladic Detachment System (WCDS). Based on structural fieldwork, together with microstructural observations and anisotropy of magnetic susceptibility, we recognize a continuum of deformation from magmatic to brittle conditions within the magmatic body. This succession of deformation events is kinematically compatible with the development of the WCDS. The architecture of the pluton shows a marked asymmetry resulting from its interaction with the detachments. We propose a tectonic scenario for the emplacement of Serifos pluton and its subsequent cooling during the Aegean extension: (1) A first stage corresponds to the metamorphic core complex initiation and associated southwestward shearing along the Meghàlo Livadhi detachment. (2) In the second stage, the Serifos pluton has intruded the dome at shallow crustal level, piercing through the ductile/brittle Meghàlo Livadhi detachment. Southwest directed extensional deformation was contemporaneously transferred upward in the crust along the more localized Kàvos Kiklopas detachment. (3) The third stage was marked by synmagmatic extensional deformation and strain localization at the contact between the pluton and the host rocks resulting in nucleation of narrow shear zones, which (4) continued to develop after the pluton solidification.

  16. Electrocatalytic Oxidation of Formate with Nickel Diphosphane Dipeptide Complexes. Effect of Ligands Modified with Amino Acids

    Energy Technology Data Exchange (ETDEWEB)

    Galan, Brandon R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Reback, Matthew L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jain, Avijita [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Appel, Aaron M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Shaw, Wendy J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2013-09-03

    A series of nickel bis-diphosphine complexes with dipeptides appended to the ligands were investigated for the catalytic oxidation of formate. Typical rates of ~7 s-1 were found, similar to the parent complex (~8 s-1), with amino acid size and positioning contributing very little to rate or operating potential. Hydroxyl functionalities did result in lower rates, which were recovered by protecting the hydroxyl group. The results suggest that the overall dielectric introduced by the dipeptides does not play an important role in catalysis, but free hydroxyl groups do influence activity suggesting contributions from intra- or intermolecular interactions. These observations are important in developing a fundamental understanding of the affect that an enzyme-like outer coordination sphere can have upon molecular catalysts. This work was funded by the US DOE Basic Energy Sciences, Chemical Sciences, Geoscience and Biosciences Division (BRG, AJ, AMA, WJS), the US DOE Basic Energy Sciences, Physical Bioscience program (MLR). Pacific Northwest National Laboratory is operated by Battelle for the U.S. Department of Energy.

  17. Soft versus hard junction formation for α-terthiophene molecular wires and their charge transfer complexes

    Science.gov (United States)

    Vezzoli, Andrea; Grace, Iain M.; Brooke, Carly; Nichols, Richard J.; Lambert, Colin J.; Higgins, Simon J.

    2017-03-01

    We used a range of scanning tunnelling microscopy (STM)-based methods to conduct a detailed study of single molecule junction conductance enhancement upon charge transfer complex formation, using bis(thiaalkyl)arene molecular wires as electron donors and tetracyanoethylene (TCNE) as an electron acceptor. Using the "hard" STM break junction (STM-BJ) method, in which a Au STM tip is pushed into a Au substrate and then withdrawn in the presence of molecules, we see a single, very broad, peak in the resulting conductance histogram when all data are used; the conductance enhancement is 25-fold for a terthiophene donor and 15-fold for a phenyl group. After rational data selection, in which only current-distance curves that contain a current plateau >0.2 nm long are used in the conductance histogram, three sharper peaks are resolved in the histograms for the charge transfer complexes; two substantially lower-conductance peaks are resolved for the uncomplexed molecules. Using the "soft" STM I(s) technique, in which initial contact between tip and substrate is avoided and the current limit is about an order of magnitude lower, we were able to resolve two peaks for the uncomplexed molecules depending upon the initial set point current (i.e., tip height), one at the same value as the lower of the two data-selected STM-BJ histogram peaks and an additional peak beyond the low-current limit for the STM-BJ experiment. For the terthiophene, the low, medium, and high conductance peaks for the TCNE complex are, respectively, ca. 70, 70, and 46 times higher in conductance than the corresponding peaks for the free molecule.

  18. Oceanic crust formation in the Egeria Fracture Zone Complex (Central Indian Ocean)

    Science.gov (United States)

    Le Minor, Marine; Gaina, Carmen; Sigloch, Karin; Minakov, Alexander

    2016-04-01

    This study aims to analyse in detail the oceanic crust fabric and volcanic features (seamounts) formed for the last 10 million years at the Central Indian Ridge between 19 and 21 latitude south. Multibeam bathymetry and magnetic data has been collected in 2013 as part of the French-German expedition RHUM-RUM (Reunion hotspot and upper mantle - Reunion's unterer mantel). Three long profiles perpendicular on the Central Indian Ridge (CIR), south of the Egeria fracture zone, document the formation of oceanic crust since 10 million years, along with changes in plate kinematics and variations in the magmatic input. We have inspected the abyssal hill geometry and orientation along conjugate oceanic flanks and within one fracture zone segment where we could identify J-shaped features that are indicators of changes in plate kinematics. The magnetic anomaly data shows a slight asymmetry in seafloor spreading rates on conjugate flanks: while a steady increase in spreading rate from 10 Ma to the present is shown by the western flank, the eastern part displays a slowing down from 5 Ma onwards. The deflection of the anti J-shaped abyssal hill lineations suggest that the left-stepping Egeria fracture zone complex (including the Egeria, Flinders and an un-named fracture zone to the southeast) was under transpression from 9 to 6 Ma and under transtension since 3 Ma. The transpressional event was triggered by a clockwise mid-ocean ridge reorientation and a decrease of its offset, whereas the transtensional regime was probably due to a counter-clockwise change in the spreading direction and an increase of the ridge offset. The new multibeam data along the three profiles reveal that crust on the eastern side is smoother (as shown by the abyssal hill number and structure) and hosts several seamounts (with age estimations of 7.67, 6.10 and 0.79 Ma), in contrast to the rougher conjugate western flank. Considering that the western flank was closer to the Reunion plume, and therefore

  19. Formation of ethylene glycol and other complex organic molecules in star-forming regions

    Science.gov (United States)

    Rivilla, V. M.; Beltrán, M. T.; Cesaroni, R.; Fontani, F.; Codella, C.; Zhang, Q.

    2017-02-01

    Context. The detection of complex organic molecules related with prebiotic chemistry in star-forming regions allows us to investigate how the basic building blocks of life are formed. Aims: Ethylene glycol (CH2OH)2 is the simplest sugar alcohol and the reduced alcohol of the simplest sugar glycoladehyde (CH2OHCHO). We study the molecular abundance and spatial distribution of (CH2OH)2, CH2OHCHO and other chemically related complex organic species (CH3OCHO, CH3OCH3, and C2H5OH) towards the chemically rich massive star-forming region G31.41+0.31. Methods: We analyzed multiple single-dish (Green Bank Telescope and IRAM 30 m) and interferometric (Submillimeter Array) spectra towards G31.41+0.31, covering a range of frequencies from 45 to 258 GHz. We fitted the observed spectra with a local thermodynamic equilibrium (LTE) synthetic spectra, and obtained excitation temperatures and column densities. We compared our findings in G31.41+0.31 with the results found in other environments, including low- and high-mass star-forming regions, quiescent clouds and comets. Results: We report for the first time the presence of the aGg' conformer of (CH2OH)2 towards G31.41+0.31, detecting more than 30 unblended lines. We also detected multiple transitions of other complex organic molecules such as CH2OHCHO, CH3OCHO, CH3OCH3, and C2H5OH. The high angular resolution images show that the (CH2OH)2 emission is very compact, peaking towards the maximum of the 1.3 mm continuum. These observations suggest that low abundance complex organic molecules, like (CH2OH)2 or CH2OHCHO, are good probes of the gas located closer to the forming stars. Our analysis confirms that (CH2OH)2 is more abundant than CH2OHCHO in G31.41+0.31, as previously observed in other interstellar regions. Comparing different star-forming regions we find evidence of an increase of the (CH2OH)2/CH2OHCHO abundance ratio with the luminosity of the source. The CH3OCH3/CH3OCHO and (CH2OH)2/C2H5OH ratios are nearly constant with

  20. Thermodynamic properties of actinide complexes. II. Thorium(IV)--acetate system. [Formation of thorium(IV)-acetate complexes in aqueous perchlorate medium

    Energy Technology Data Exchange (ETDEWEB)

    Portanova, R.; Di Bernardo, P.; Traverso, O.; Mazzocchin, G.A.; Magon, L.

    1975-10-01

    The changes in free energy, enthalpy and entropy for the formation of thorium(IV)--acetate complexes have been determined at 25/sup 0/C and in 1.00 M aqueous perchlorate-medium. All five complexes formed, are found to be stabilized by a large gain of entropy. The marked increase in the values of ..delta..H/sub j/ and ..delta..S/sub j/, relative to the third step of complexation has been explained in terms of a coordination change.

  1. Evolution of multi-mineral formation evaluation using LWD data in complex carbonates offshore Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Ferraris, Paolo; Borovskaya, Irina [Schlumberger, Houston, TX (United States)

    2012-07-01

    Petrophysical Formation Evaluation using Logging While Drilling (LWD) measurements is a new requisite when drilling in carbonates reservoirs offshore Brazil. These reservoirs are difficult to characterize due to an unusual mixture of the minerals constituting the matrix and affecting rock texture. As wells are getting deeper and more expensive, an early identification of the drilled targets potential is necessary for valuable decisions. Brazil operators have been especially demanding towards service providers, pushing for development of suitable services able to positively identify and quantify not only the presence of hydrocarbons but also their flowing capability. In addition to the standard gamma ray / resistivity / porosity and density measurements, three new measurements have proven to be critical to evaluate complex carbonate formations: Nuclear Magnetic Resonance (NMR), Spectroscopy and Capture Cross-Section (sigma). Under appropriate logging conditions, NMR data provides lithology independent porosity, bound and free fluids fractions, reservoir texture and permeability. Capture Spectroscopy allows assessment of mineral composition in terms of calcite, dolomite, quartz and clay fractions, and in addition highlights presence of other heavier minerals. Finally, sigma allows performing a volumetric formation evaluation without requiring custom optimization of the classical exponents used in all forms of resistivity saturation equations. All these new measurements are inherently statistical and if provided by wireline after drilling the well they may result in significant usage of rig time. When acquired simultaneously while drilling they have three very clear advantages: 1) no extra rig time, 2) improved statistics due to long formation exposure (drilling these carbonates is a slow process and rate of penetration (ROP) rarely exceeds 10 m/hr), 3) less invasion effect and better hole condition. This paper describes the development of two LWD tools performing the

  2. From PII signaling to metabolite sensing: a novel 2-oxoglutarate sensor that details PII-NAGK complex formation.

    Directory of Open Access Journals (Sweden)

    Jan Lüddecke

    Full Text Available The widespread PII signal transduction proteins are known for integrating signals of nitrogen and energy supply and regulating cellular behavior by interacting with a multitude of target proteins. The PII protein of the cyanobacterium Synechococcus elongatus forms complexes with the controlling enzyme of arginine synthesis, N-acetyl-L-glutamate kinase (NAGK in a 2-oxoglutarate- and ATP/ADP-dependent manner. Fusing NAGK and PII proteins to either CFP or YFP yielded a FRET sensor that specifically responded to 2-oxoglutarate. The impact of the fluorescent tags on PII and NAGK was evaluated by enzyme assays, surface plasmon resonance spectroscopy and isothermal calorimetric experiments. The developed FRET sensor provides real-time data on PII - NAGK interaction and its modulation by the effector molecules ATP, ADP and 2-oxoglutarate in vitro. Additionally to its utility to monitor 2-oxoglutarate levels, the FRET assay provided novel insights into PII - NAGK complex formation: (i It revealed the formation of an encounter-complex between PII and NAGK, which holds the proteins in proximity even in the presence of inhibitors of complex formation; (ii It revealed that the PII T-loop residue Ser49 is neither essential for complex formation with NAGK nor for activation of the enzyme but necessary to form a stable complex and efficiently relieve NAGK from arginine inhibition; (iii It showed that arginine stabilizes the NAGK hexamer and stimulates PII - NAGK interaction.

  3. Complex formation reactions of lanthanum(III), cerium(III), thorium(IV), dioxouranyl(IV) complexes with tricine.

    Science.gov (United States)

    Mohamed, Mahmoud M A

    2007-08-01

    Equilibrium studies for the heavy metal ions La(III), Ce(III), Th(IV) and UO2(IV) (M) complexes of the zwitterionic buffer tricine (L) in aqueous solution are investigated. Stoichiometry and stability constants for the different complexes formed as well as hydrolysis products of the metal cations are determined at 25 degrees C and ionic strength 0.1 M NaNO3. The stability of the formed complexes are discussed in terms of the nature of the heavy metal cation. The solid complexes are synthesized and characterized by means of elemental analysis, FTIR, and TG analysis. The general molecular formulae of the obtained complexes is suggested to be [M(L)2](NO3)n-2(H2O)x, where n = the charge of the metal cation, x = no. of water molecules.

  4. Swarming and complex pattern formation in Paenibacillus vortex studied by imaging and tracking cells

    Directory of Open Access Journals (Sweden)

    Jacob Eshel

    2008-02-01

    Full Text Available Abstract Background Swarming motility allows microorganisms to move rapidly over surfaces. The Gram-positive bacterium Paenibacillus vortex exhibits advanced cooperative motility on agar plates resulting in intricate colonial patterns with geometries that are highly sensitive to the environment. The cellular mechanisms that underpin the complex multicellular organization of such a simple organism are not well understood. Results Swarming by P. vortex was studied by real-time light microscopy, by in situ scanning electron microscopy and by tracking the spread of antibiotic-resistant cells within antibiotic-sensitive colonies. When swarming, P. vortex was found to be peritrichously flagellated. Swarming by the curved cells of P. vortex occurred on an extremely wide range of media and agar concentrations (0.3 to 2.2% w/v. At high agar concentrations (> 1% w/v rotating colonies formed that could be detached from the main mass of cells by withdrawal of cells into the latter. On lower percentage agars, cells moved in an extended network composed of interconnected "snakes" with short-term collision avoidance and sensitivity to extracts from swarming cells. P. vortex formed single Petri dish-wide "supercolonies" with a colony-wide exchange of motile cells. Swarming cells were coupled by rapidly forming, reversible and non-rigid connections to form a loose raft, apparently connected via flagella. Inhibitors of swarming (p-Nitrophenylglycerol and Congo Red were identified. Mitomycin C was used to trigger filamentation without inhibiting growth or swarming; this facilitated dissection of the detail of swarming. Mitomycin C treatment resulted in malcoordinated swarming and abortive side branch formation and a strong tendency by a subpopulation of the cells to form minimal rotating aggregates of only a few cells. Conclusion P. vortex creates complex macroscopic colonies within which there is considerable reflux and movement and interaction of cells. Cell

  5. Formation of metamorphic core complexes in non-over-thickened continental crust: A case study of Liaodong Peninsula (East Asia)

    OpenAIRE

    Wang, Kun; Burov, Evgueni; Gumiaux, Charles; Chen, Yan; Lu, Gang; Mezri, Leila; Zhao, Liang

    2015-01-01

    International audience; Pre-thickened hot orogenic crust is often considered a necessary condition for the formation of continental metamorphic core complexes (MCCs). However, the discovery of MCCs in the Liaodong Peninsula, where the crust has a normal thickness (~ 35 km), challenges the universality of this scenario. Therefore, we implement a series of 2-D numerical thermo-mechanical modeling experiments in which we investigate the conditions of MCC formation in normal crusts, as well as th...

  6. Protostellar Interferometric Line Survey (PILS): Constraining the formation of complex organic molecules with ALMA

    Science.gov (United States)

    Jorgensen, Jes K.; Coutens, Audrey; Bourke, Tyler L.; Favre, Cecile; Garrod, Robin; Lykke, Julie; Mueller, Holger; Oberg, Karin I.; Schmalzl, Markus; van der Wiel, Matthijs; van Dishoeck, Ewine; Wampfler, Susanne F.

    2015-08-01

    Understanding how, when and where complex organic and potentially prebiotic molecules are formed is a fundamental goal of astrochemistry and an integral part of origins of life studies. Already now ALMA is showing its capabilities for studies of the chemistry of solar-type stars with its high sensitivity for faint lines, high spectral resolution which limits line confusion, and high angular resolution making it possible to study the structure of young protostars on solar-system scales. We here present the first results from a large unbiased survey “Protostellar Interferometric Line Survey (PILS)” targeting one of the astrochemical template sources, the low-mass protostellar binary IRAS 16293-2422. The survey is more than an order of magnitude more sensitive than previous surveys of the source and provide imaging down to 25 AU scales (radius) around each of the two components of the binary. An example of one of the early highlights from the survey is unambiguous detections of the (related) prebiotic species glycolaldehyde, ethylene glycol (two lowest energy conformers), methyl formate and acetic acid. The glycolaldehyde-ethylene glycol abundance ratio is high in comparison to comets and other protostars - but agrees with previous measurements, e.g., in the Galactic Centre clouds possibly reflecting different environments and/or evolutionary histories. Complete mapping of this and other chemical networks in comparison with detailed chemical models and laboratory experiments will reveal the origin of complex organic molecules in a young protostellar system and investigate the link between these protostellar stages and the early Solar System.

  7. Development of excretion stimulating techniques for radioactive materials via complex formation

    Energy Technology Data Exchange (ETDEWEB)

    Takaya, Haruo; Utsumi, Akira; Takatsu, Akiko [National Inst. of materials and Chemical Research, Tsukuba, Ibaraki (Japan)

    1999-02-01

    This research project aimed to establish a technique for rapid excretion of RI metals (Ni, Cd, Pb) incorporated into human body and here, development of removing agents which allow complex formation with metals was attempted. The reactivities of those agents with metals such as Ni, Cd were investigated. The gluco-formazan derivatives produced in the previous year; PF, PCF, PHF, PPF, PPCF and PPHF were investigated in the respect of reactivities with various metals. Those formazan derivatives were mixed with a metal ion (alkaline earth metals, lanthanoids, 1st transition metal) in buffered sodium-perchlorate solution to determine the chelating activity and the stability of metal chelation was estimated by spectrophotometric method. In formazan derivative with glucose, mannose or galactose, N atom of imino, azo and pyridyl groups, and O atoms of carboxyl and hydroxy groups possibly mediate the bonding with a metal ion. These chelate agents were little reactive for alkali metals, alkaline earth metals (Mg, Sr, Ba) or lanthanoid elements, but their affinities to Zn, Cd, Ni and Co were very high. It was demonstrated that either of the formazan derivatives was able to make chelate complex, suggesting that those are usable for excretion of RI metal ({sup 63}Ni and {sup 109}Cd). These gluco-formazan thus obtained were able to excrete these RI metals in the human body without affecting the metabolism of physiologically indispensable metals such as Ca, Mg, Fe etc. Furthermore, it seems necessary to make pharmacokinetic study on absorption, distribution, metabolism, excretion of the gluco-formazan derivatives. (M.N.)

  8. ENVIRONMENTALLY FRIENDLY COMPLEXONES. THE THERMODYNAMIC CHARACTERISTICS OF THE FORMATION OF AL3+ ION COMPLEXES WITH ETHYLENEDIAMINEDISUCCINIC ACID IN AQUEOUS SOLUTIONS

    Directory of Open Access Journals (Sweden)

    L.N. Tolkacheva

    2012-06-01

    Full Text Available Complex formation between Al3+ and ethylenediamine - N,N`-disuccinic acid (H4L was studied at 25°C against the background of 0.1, 0.5, 1.0 N solutions of KNO3 by potentiometry and mathematical modeling. The extrapolation of concentration constants to zero ionic strength was used to calculate the thermodynamic constants of the formation of the AlL–, AlHL complexes using an equation with one individual parameter (logβ0 = 16.27 ± 0.07, 9.19 ± 0.2 respectively.

  9. Apatite formation behaviour during metasomatism in the Bathtub Intrusion (Babbitt deposit, Duluth Complex, USA)

    Science.gov (United States)

    Raič, Sara; Mogessie, Aberra; Krenn, Kurt; Hauzenberger, Christoph A.; Tropper, Peter

    2016-04-01

    The mineralized troctolitic Bathtub intrusion (Duluth Complex, NE-Minnesota) is known for its famous Cu-Ni-Sulfide±PGM Babbitt deposit, where platinum group minerals (PGMs) are either hosted by primary magmatic sulfides (base metal sulfides) or associated with hydrothermally altered portions. This secondary generation of PGMs is present in alteration patches and suggests the involvement of hydrothermal fluids in the mobilization of platinum-group elements (PGEs). Accessory fluorapatite in these samples reveals besides H2O- and CO2-rich primary fluid inclusions, textural and compositional variations that also record magmatic and metasomatic events. Based on detailed back-scattered electron imaging (BSE) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICPMS), a primary magmatic origin is reflected by homogeneous or zoned grains, where zoning patterns are either concentric or oscillatory, with respect to LREE. Late magmatic to hydrothermal processes are indicated by grains with bright LREE-enriched rims or conversion textures with REE-enriched patches in the interior of the apatite. A metasomatic formation of monazite from apatite is documented by the presence of monazite inclusions in apatite and newly grown monazite at altered apatite rims. They formed by the release of REEs from the apatite during a fluid-induced alteration, based on the coupled substitution Ca2+ + P5+ = REE3+ + Si4+ (Rønsbo 1989; Rønsbo 2008). Samples with monazite inclusions in apatite further display occurrences of PGMs associated with hydrothermal alteration patches (chlorite + amphibole). The presence of H2O- and CO2-rich fluid inclusions in apatite, the metasomatically induced monazite growth, as well as the occurrence of PGMs in hydrothermally alteration zones, also suggest the involvement of aqueous chloride complexes in a H2O dominated fluid in the transportation of LREE and redistribution of the second generation of PGEs. Rønsbo, J.G. (1989): Coupled substitutions

  10. Structure Formation of Ultrathin PEO Films at Solid Interfaces—Complex Pattern Formation by Dewetting and Crystallization

    Directory of Open Access Journals (Sweden)

    Hans-Georg Braun

    2013-02-01

    Full Text Available The direct contact of ultrathin polymer films with a solid substrate may result in thin film rupture caused by dewetting. With crystallisable polymers such as polyethyleneoxide (PEO, molecular self-assembly into partial ordered lamella structures is studied as an additional source of pattern formation. Morphological features in ultrathin PEO films (thickness < 10 nm result from an interplay between dewetting patterns and diffusion limited growth pattern of ordered lamella growing within the dewetting areas. Besides structure formation of hydrophilic PEO molecules, n-alkylterminated (hydrophobic PEO oligomers are investigated with respect to self-organization in ultrathin films. Morphological features characteristic for pure PEO are not changed by the presence of the n-alkylgroups.

  11. THE PRINCIPLES OF POWER-RISE BUILDINGS COMPLEXES FORMATION USING WIND ENERGY

    Directory of Open Access Journals (Sweden)

    NEVGAMONNIY G. U.

    2015-11-01

    Full Text Available Raising of problem. The methodology of designing energy-efficient tower building should be based on systematic analysis of the building as a unified energy system. The prominent architect Norman Foster (Sir Norman Foster writes: "Architects cannot solve all the world's environmental problems, but we can design buildings that require only a fraction of current energy consumption, in addition, through proper urban planning we can affect traffic flows. The location and functionality of buildings, its structural flexibility and technological resources, orientation, shape and structure, heating and ventilation characteristics used in the construction materials - all these parameters affect the amount of energy required for the construction, operation and maintenance of the building, and as for transportation, moving to it and from it" [1]. Purpose. The purpose of the study is scientific justification principles of architectural formation decisions of the power-rise energy efficient complexes and developing methods of architectural design of PRBC using wind energy. To develop the science-based principles forming the architectural buildings with the use of alternative energy and determine the specific features of the architectural design of buildings. Conclusion. The principles of architectural forming in the use of wind power and identify possible trends for the development of buildings with integrated wind installations. Polyfunctional wind power plants are in special properties of certain material and structural elements of the building structure, improve aerodynamic performance of the outer shell and therefore wind energy devices. Thus, the power efficiency of energy active building depends on its space solutions.

  12. Calculating the contribution of different binding modes to Quinacrine - DNA complex formation from polarized fluorescence data

    CERN Document Server

    Voloshin, Igor; Karachevtsev, Victor; Zozulya, Victor

    2013-01-01

    Binding of acridine derivative quinacrine (QA) to chicken erythrocyte DNA was studied by methods of absorption and polarized fluorescent spectroscopy. Measurements were carried out in aqueous buffered solutions (pH 6.9) of different dye concentrations (QA concentration range from $10^{-6}$ till $10^{-4}$ M) and ionic strengths ($Na^{+}$ concentration rang from $10^{-3}$ till 0.15 M) in a wide range of phosphate-to-dye molar ratios ($P/D$). It is established that the minimum of fluorescent titration curve plotted as relative fluorescence intensity $vs$ $P/D$ is conditioned by the competition between the two types of QA binding to DNA which posses by different emission parameters: (i) intercalative one dominating under high $P/D$ values, and (ii) outside electrostatic binding dominating under low $P/D$ values, which is accompanied by the formation of non-fluorescent dye associates on the DNA backbone. Absorption and fluorescent characteristics of complexes formed were determined. The method of calculation of di...

  13. CD8+ TCR repertoire formation is guided primarily by the peptide component of the antigenic complex.

    Science.gov (United States)

    Koning, Dan; Costa, Ana I; Hoof, Ilka; Miles, John J; Nanlohy, Nening M; Ladell, Kristin; Matthews, Katherine K; Venturi, Vanessa; Schellens, Ingrid M M; Borghans, Jose A M; Kesmir, Can; Price, David A; van Baarle, Debbie

    2013-02-01

    CD8(+) T cells recognize infected or dysregulated cells via the clonotypically expressed αβ TCR, which engages Ag in the form of peptide bound to MHC class I (MHC I) on the target cell surface. Previous studies have indicated that a diverse Ag-specific TCR repertoire can be beneficial to the host, yet the determinants of clonotypic diversity are poorly defined. To better understand the factors that govern TCR repertoire formation, we conducted a comprehensive clonotypic analysis of CD8(+) T cell populations directed against epitopes derived from EBV and CMV. Neither pathogen source nor the restricting MHC I molecule were linked with TCR diversity; indeed, both HLA-A and HLA-B molecules were observed to interact with an overlapping repertoire of expressed TRBV genes. Peptide specificity, however, markedly impacted TCR diversity. In addition, distinct peptides sharing HLA restriction and viral origin mobilized TCR repertoires with distinct patterns of TRBV gene usage. Notably, no relationship was observed between immunodominance and TCR diversity. These findings provide new insights into the forces that shape the Ag-specific TCR repertoire in vivo and highlight a determinative role for the peptide component of the peptide-MHC I complex on the molecular frontline of CD8(+) T cell-mediated immune surveillance.

  14. Measurement of the formation of complexes in tyrosine kinase-mediated signal transduction

    Energy Technology Data Exchange (ETDEWEB)

    Ladbury, John E., E-mail: j.ladbury@biochem.ucl.ac.uk [Department of Biochemistry and Molecular Biology, University College London, Gower Street, London WC1E 6BT (United Kingdom)

    2007-01-01

    The use of isothermal titration calorimetry (ITC) provides a full thermodynamic characterization of an interaction in one experiment. The determination of the affinity is an important value; however, the additional layer of information provided by the change in enthalpy and entropy can help in understanding the biology. This is demonstrated with respect to tyrosine kinase-mediated signal transduction. Isothermal titration calorimetry (ITC) provides highly complementary data to high-resolution structural detail. An overview of the methodology of the technique is provided. Ultimately, the correlation of the thermodynamic parameters determined by ITC with structural perturbation observed on going from the free to the bound state should be possible at an atomic level. Currently, thermodynamic data provide some insight as to potential changes occurring on complex formation. Here, this is demonstrated in the context of in vitro quantification of intracellular tyrosine kinase-mediated signal transduction and the issue of specificity of the important interactions. The apparent lack of specificity in the interactions of domains of proteins involved in early signalling from membrane-bound receptors is demonstrated using data from ITC.

  15. Formation and identification of unresolved complex mixtures in lacustrine biodegraded oil from Nanxiang Basin, China.

    Science.gov (United States)

    Guo, Pengfei; He, Sheng; Zhu, Shukui; Chai, Derong; Yin, Shiyan; Dai, Wei; Zhang, Wanfeng

    2014-01-01

    A comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC × GC/TOFMS) method has been developed for the formation and identification of unresolved complex mixtures (UCMs) in lacustrine biodegraded oils that with the same source rock, similar maturity, and increasing degradation rank from Nanxiang Basin, China. Normal alkanes, light hydrocarbons, isoprenoids, steranes, and terpanes are degraded gradually from oil B330 to oil G574. The compounds in biodegraded oil (oil G574) have fewer types, the polarity difference of compounds in different types is minor, and the relative content of individual compounds is similar. All the features make the compounds in biodegraded oil coelute in GC analysis and form the raised "baseline hump" named UCMs. By injecting standard materials and analyzing mass spectrums of target compounds, it is shown that cyclic alkanes with one to five rings are the major components of UCMs. Furthermore, UCMs were divided into six classes. Classes I and II, composed of alkyl-cyclohexanes, alkyl-naphthanes, and their isomers, are originated from the enrichment of hydrocarbons resistant to degradation in normal oils. Classes III ~ VI, composed of sesquiterpenoids, tricyclic terpanes, low molecular steranes, diasteranes, norhopanes, and their isomers, are probably from some newly formed compounds during the microbial transformation of oil.

  16. Formation and Identification of Unresolved Complex Mixtures in Lacustrine Biodegraded Oil from Nanxiang Basin, China

    Directory of Open Access Journals (Sweden)

    Pengfei Guo

    2014-01-01

    Full Text Available A comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC × GC/TOFMS method has been developed for the formation and identification of unresolved complex mixtures (UCMs in lacustrine biodegraded oils that with the same source rock, similar maturity, and increasing degradation rank from Nanxiang Basin, China. Normal alkanes, light hydrocarbons, isoprenoids, steranes, and terpanes are degraded gradually from oil B330 to oil G574. The compounds in biodegraded oil (oil G574 have fewer types, the polarity difference of compounds in different types is minor, and the relative content of individual compounds is similar. All the features make the compounds in biodegraded oil coelute in GC analysis and form the raised “baseline hump” named UCMs. By injecting standard materials and analyzing mass spectrums of target compounds, it is shown that cyclic alkanes with one to five rings are the major components of UCMs. Furthermore, UCMs were divided into six classes. Classes I and II, composed of alkyl-cyclohexanes, alkyl-naphthanes, and their isomers, are originated from the enrichment of hydrocarbons resistant to degradation in normal oils. Classes III ~ VI, composed of sesquiterpenoids, tricyclic terpanes, low molecular steranes, diasteranes, norhopanes, and their isomers, are probably from some newly formed compounds during the microbial transformation of oil.

  17. Complexation and sequestration of BMP-2 from an ECM mimetic hyaluronan gel for improved bone formation.

    Directory of Open Access Journals (Sweden)

    Marta Kisiel

    Full Text Available Bone morphogenetic protein-2 (BMP-2 is considered a promising adjuvant for the treatment of skeletal non-union and spinal fusion. However, BMP-2 delivery in a conventional collagen scaffold necessitates a high dose to achieve an efficacious outcome. To lower its effective dose, we precomplexed BMP-2 with the glycosaminoglycans (GAGs dermatan sulfate (DS or heparin (HP, prior to loading it into a hyaluronic acid (HA hydrogel. In vitro release studies showed that BMP-2 precomplexed with DS or HP had a prolonged delivery compared to without GAG. BMP-2-DS complexes achieved a slightly faster release in the first 24 h than HP; however, both delivered BMP-2 for an equal duration. Analysis of the kinetic interaction between BMP-2 and DS or HP showed that HP had approximately 10 times higher affinity for BMP-2 than DS, yet it equally stabilized the protein, as determined by alkaline phosphatase activity. Ectopic bone formation assays at subcutaneous sites in rats demonstrated that HA hydrogel-delivered BMP-2 precomplexed with GAG induced twice the volume of bone compared with BMP-2 delivered uncomplexed to GAG.

  18. Decamethylytterbocene Complexes of Bipyridines and Diazabutadienes: Multiconfigurational Ground States and Open-Shell Singlet Formation

    Energy Technology Data Exchange (ETDEWEB)

    Booth, Corwin H.; Walter, Marc D.; Kazhdan, Daniel; Hu, Yung-Jin; Lukens, Wayne W.; Bauer, Eric D.; Maron, Laurent; Eisenstein, Odile; Andersen, Richard A.

    2009-04-22

    Partial ytterbium f-orbital occupancy (i.e., intermediate valence) and open-shell singlet formation are established for a variety of bipyridine and diazabutadiene adducts with decamethylytterbocene, (C5Me5)2Yb, abbreviated as Cp*2Yb. Data used to support this claim include ytterbium valence measurements using Yb LIII-edge X-ray absorption near-edge structure spectroscopy, magnetic susceptibility, and complete active space self-consistent field (CASSCF) multiconfigurational calculations, as well as structural measurements compared to density functional theory calculations. The CASSCF calculations indicate that the intermediate valence is the result of a multiconfigurational ground-state wave function that has both an open-shell singlet f13(?*)1, where pi* is the lowest unoccupied molecular orbital of the bipyridine or dpiazabutadiene ligands, and a closed-shell singlet f14 component. A number of other competing theories for the unusual magnetism in these materials are ruled out by the lack of temperature dependence of the measured intermediate valence. These results have implications for understanding chemical bonding not only in organolanthanide complexes but also for f-element chemistry in general, as well as understanding magnetic interactions in nanoparticles and devices.

  19. Decamethylytterbocene complexes of bipyridines and diazabutadines: multiconfigurational ground states and open-shell singlet formation

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Eric D [Los Alamos National Laboratory; Booth, C H [LBNL; Walter, M D [LBNL; Kazhdan, D [LBNL; Hu, Y - J [LBNL; Lukens, Wayne [LBNL; Maron, Laurent [INSA TOULOUSE; Eisentein, Odile [UNIV MONTPELLIER 2; Anderson, Richard [LBNL

    2009-01-01

    Partial ytterbium f-orbital occupancy (i.e. intermediate valence) and open-shell singlet Draft 12/formation are established for a variety of bipyridine and diazabutadiene adducts to decamethylytterbocene, (C{sub 5}Me{sub 5}){sub 2}Yb or Cp*{sub 2}Yb. Data used to support this claim includes ytterbium valence measurements using Yb Lm-edge x-ray absorption near-edge structure (XANES) spectroscopy, magnetic susceptibility and Complete Active Space Self-Consistent Field (CASSCF) multi configurational calculations, as well as structural measurements compared to density-functional theory (DFT) calculations. The CASSCF calculations indicate that the intermediate valence is the result of a multiconfigurational ground state wave function that has both an open-shell singlet f{sup 13} and a closed-shell singlet f{sup 14} component. A number of other competing theories for the unusual magnetism in these materials are ruled out by the presence of intermediate valence and its lack of any significant temperature dependence. These results have implications for understanding chemical bonding not only in organolanthanide complexes, but also for organometallic chemistry in general, as well as understanding magnetic interactions in nanopartic1es and devices.

  20. Multiple episodes of star formation in the CN15/16/17 molecular complex

    CERN Document Server

    Gennaro, M; Brandner, W; Stolte, A; Rochau, B; Beuther, H; Gouliermis, D; Tackenberg, J; Kudryavtseva, N; Hussmann, B; Schuller, F; Henning, Th

    2012-01-01

    We have started a campaign to identify massive star clusters inside bright molecular bubbles towards the Galactic Center. The CN15/16/17 molecular complex is the first example of our study. The region is characterized by the presence of two young clusters, DB10 and DB11, visible in the NIR, an ultra-compact HII region identified in the radio, several young stellar objects visible in the MIR, a bright diffuse nebulosity at 8\\mu m coming from PAHs and sub-mm continuum emission revealing the presence of cold dust. Given its position on the sky (l=0.58, b=-0.85) and its kinematic distance of ~7.5 kpc, the region was thought to be a very massive site of star formation in proximity of the CMZ. The cluster DB11 was estimated to be as massive as 10^4 M_sun. However the region's properties were known only through photometry and its kinematic distance was very uncertain given its location at the tangential point. We aimed at better characterizing the region and assess whether it could be a site of massive star formatio...

  1. Reaction of a copper(II)-nitrosyl complex with hydrogen peroxide: putative formation of a copper(I)-peroxynitrite intermediate.

    Science.gov (United States)

    Kalita, Apurba; Kumar, Pankaj; Mondal, Biplab

    2012-05-14

    The reaction of a Cu(II)-nitrosyl complex (1) with hydrogen peroxide at -20 °C in acetonitrile results in the formation of the corresponding Cu(I)-peroxynitrite intermediate. The reduction of the Cu(II) center was monitored by UV-visible spectroscopic studies. Formation of the peroxynitrite intermediate has been confirmed by its characteristic phenol ring nitration reaction as well as isolation of corresponding Cu(I)-nitrate (2). On air oxidation, 2 resulted in the corresponding Cu(II)-nitrate (3). Thus, these results demonstrate a possible decomposition pathway for H(2)O(2) and NO through the formation of a peroxynitrite intermediate in biological systems.

  2. Thermodynamics of mixed-ligand complex formation of zinc nitrilotriacetate with amino acids and dipeptides in solution

    Energy Technology Data Exchange (ETDEWEB)

    Pyreu, Dmitrii, E-mail: pyreu@mail.ru [Department of Inorganic and Analytic Chemistry, Ivanovo State UniversityErmak 39, Ivanovo 153025 (Russian Federation); Gruzdev, Matvey; Kumeev, Roman [G.A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences, Ivanovo (Russian Federation); Gridchin, Sergei [Ivanovo State University of Chemistry and Technology, Ivanovo (Russian Federation)

    2014-10-20

    Highlights: • Stable mixed ligand complexes of ZnNta with amino acids and dipeptides. • Histamine-like coordination mode of His in the complex ZnNtaHis. • Glycine-like coordination of Lys and Orn in the complexes ZnNtaL and ZnNtaHL • NH{sub 2}, CO-coordination mode of GlyGly in the complex ZnNtaGG. • NH{sub 2}, N{sup −} or NH2, N{sup −}, COO-coordination modes of GlyGly in the complex ZnNtaGGH{sub −1}. - Abstract: The isothermal calorimetry, pH-potentiometric titration and {sup 1}H and {sup 13}C NMR methods has been used to study the mixed-ligand complex formation in the systems Zn{sup 2+}–Nta{sup 3–}–L{sup −} (L = His, Orn, Lys, GlyGly, AlaAla) in aqueous solution at 298.15 K and the ionic strength of I = 0.5 (KNO{sub 3}). The thermodynamic parameters of formation of the mixed complexes have been determined. The relationship between the probable coordination modes of the complexone and amino acid or dipeptide molecules in the mixed-ligand complex and the thermodynamic parameters has been discussed.

  3. Complexes of hydroxamates. V: Equilibrium and kinetics of the formation of the binary and ternary complexes involved in the nickel(II)-histidinehydroxamic acid-pyridoxal system.

    Science.gov (United States)

    el-Ezaby, M S; Shuaib, N M; Marafie, H M; Hassan, M M

    1988-07-01

    Equilibrium-based computer models utilizing SUPERQUAD program were made to determine the formation constants of the binary complexes of Ni(II) with histidine-hydroxamic acid (HX) from pH-metric titration data at 25 degrees C and I = 0.15 M NaCl. The species were monomeric in the pH range 3.0-8.0. The mechanism of their complex formation was determined using the stopped flow technique under the same experimental conditions of the equilibrium study. It has been concluded that Ni2+ and NiOH- were the active species in the complex formation reactions. Moreover, the reaction of HX with pyridoxal (PL) was studied in the absence of metal-ions by polarographic and spectrophotometric techniques at pH greater than or equal to 5.0. No rates were observed by using the stopped-flow methods. The formation constants for the binary system (HX-PL) and the ternary system (Ni(II)-HX-PL) were also determined by the same program applied on data obtained from pH metric titration at 25 degrees C and I = 0.15 M NaCl. Ternary complex formation involving PL and the species of the Ni(II)-HX system was also investigated kinetically in the pH range of 6.5-10.5. Several rate steps have been observed which have been interpreted qualitatively in terms of sequence of processes involving the condensation of aldehydic form of PL with amino moiety of HX. A comparison with other pertinent systems is also discussed.

  4. Formation mechanism of a silane-PVA/PVAc complex film on a glass fiber surface.

    Science.gov (United States)

    Repovsky, Daniel; Jane, Eduard; Palszegi, Tibor; Slobodnik, Marek; Velic, Dusan

    2013-10-21

    Mechanical properties of glass fiber reinforced composite materials are affected by fiber sizing. A complex film formation, based on a silane film and PVA/PVAc (polyvinyl alcohol/polyvinyl acetate) microspheres on a glass fiber surface is determined at 1) the nanoscale by using atomic force microscopy (AFM), and 2) the macroscale by using the zeta potential. Silane groups strongly bind through the Si-O-Si bond to the glass surface, which provides the attachment mechanism as a coupling agent. The silane groups form islands, a homogeneous film, as well as empty sites. The average roughness of the silanized surface is 6.5 nm, whereas it is only 0.6 nm for the non-silanized surface. The silane film vertically penetrates in a honeycomb fashion from the glass surface through the deposited PVA/PVAc microspheres to form a hexagonal close pack structure. The silane film not only penetrates, but also deforms the PVA/PVAc microspheres from the spherical shape in a dispersion to a ellipsoidal shape on the surface with average dimensions of 300/600 nm. The surface area value Sa represents an area of PVA/PVAc microspheres that are not affected by the silane penetration. The areas are found to be 0.2, 0.08, and 0.03 μm(2) if the ellipsoid sizes are 320/570, 300/610, and 270/620 nm for silane concentrations of 0, 3.8, and 7.2 μg mL(-1), respectively. The silane film also moves PVA/PVAc microspheres in the process of complex film formation, from the low silane concentration areas to the complex film area providing enough silane groups to stabilize the structure. The values for the residual silane honeycomb structure heights (Ha ) are 6.5, 7, and 12 nm for silane concentrations of 3.8, 7.2, and 14.3 μg mL(-1), respectively. The pH-dependent zeta-potential results suggest a specific role of the silane groups with effects on the glass fiber surface and also on the PVA/PVAc microspheres. The non-silanized glass fiber surface and the silane film have similar zeta potentials ranging

  5. Actinide oxalate complexes formation as a function of temperature by capillary electrophoresis coupled with inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Brunel, Benoit; Mendes, Mickael; Aupiais, Jean [CEA, DAM, DIF, Arpajon (France); Philippini, Violaine [Nice Univ. Sophia Antipolis (France). Inst. de Chimie de Nice

    2015-05-01

    Complexation of various actinides (U(VI), Np(V), Pu(V), Am(III)) by oxalato ligand was studied by capillary electrophoresis (ICPMS detection) in 0.1 mol L{sup -1} NaClO{sub 4} ionic strength solutions at various temperatures (15, 25, 35, 45 and 55 C). For each solution a unique peak was observed as a result of a fast equilibrium between the free ions and the complexes (labile systems). The results confirmed the formation of the 1:1, 1:2 and 1:3 complexes for U(VI) and Am(III); the formation of the 1:1 and 1:2 complexes for Np(V) and the formation of only 1 complex for Pu(V). For each complex, the thermodynamic parameters (the Gibbs energy Δ{sub r}G(T), the molar entropy change Δ{sub r}S(T) and the molar enthalpy change Δ{sub r}H(T{sup 0})) were fitted to the experimental data. The effect of the ionic medium was treated using the specific ion interaction theory and the thermodynamic parameters at zero ionic strength were compared to previously published data.

  6. Formats

    Directory of Open Access Journals (Sweden)

    Gehmann, Ulrich

    2012-03-01

    Full Text Available In the following, a new conceptual framework for investigating nowadays’ “technical” phenomena shall be introduced, that of formats. The thesis is that processes of formatting account for our recent conditions of life, and will do so in the very next future. It are processes whose foundations have been laid in modernity and which will further unfold for the time being. These processes are embedded in the format of the value chain, a circumstance making them resilient to change. In addition, they are resilient in themselves since forming interconnected systems of reciprocal causal circuits.Which leads to an overall situation that our entire “Lebenswelt” became formatted to an extent we don’t fully realize, even influencing our very percep-tion of it.

  7. Structure Formation of Ultrathin PEO Films at Solid Interfaces—Complex Pattern Formation by Dewetting and Crystallization.

    Science.gov (United States)

    Braun, Hans-Georg; Meyer, Evelyn

    2013-02-05

    The direct contact of ultrathin polymer films with a solid substrate may result in thin film rupture caused by dewetting. With crystallisable polymers such as polyethyleneoxide (PEO), molecular self-assembly into partial ordered lamella structures is studied as an additional source of pattern formation. Morphological features in ultrathin PEO films (thickness PEO molecules, n-alkylterminated (hydrophobic) PEO oligomers are investigated with respect to self-organization in ultrathin films. Morphological features characteristic for pure PEO are not changed by the presence of the n-alkylgroups.

  8. Complex formation of 2-(o-hydroxyphenyl)-benzoxazole and 2-(o-hydroxyphenyl)-benzothiazole with beryllium ions

    Energy Technology Data Exchange (ETDEWEB)

    Gladilovich, D.B.; Stolyarov, K.P. (Leningradskij Gosudarstvennyj Univ. (USSR))

    1984-12-01

    Using spectrophotometric and luminescence methods the interaction of beryllium ions With 2-(0-hydroxyphenyl)-benzoxazole and 2-(0-hydroxyphenyl)-benzothiazole has been studied. The formation of at least three BeL/sup +/, Be(OH)L and BeL/sub 2/ complexes (where L=singly charged anion of ligand) is established.

  9. [Electric conductivity changes in salt-free solutions in connection with the formation of polyriboadenylic and polyribouridylic acid complexes].

    Science.gov (United States)

    Filippov, S M; Vorontsova, O V; Kuznetsov, I A

    1984-01-01

    Conductometric and spectrophotometric investigations of concentrated salt-free solutions of poly(A) -- poly(U) demonstrated the 1:1 complex formation. It was accomplished by the increase of solution conductivity in contrast to the situation when DNA redenaturation takes place.

  10. A developmental framework for complex plasmodesmata formation revealed by large-scale imaging of the Arabidopsis leaf epidermis.

    Science.gov (United States)

    Fitzgibbon, Jessica; Beck, Martina; Zhou, Ji; Faulkner, Christine; Robatzek, Silke; Oparka, Karl

    2013-01-01

    Plasmodesmata (PD) form tubular connections that function as intercellular communication channels. They are essential for transporting nutrients and for coordinating development. During cytokinesis, simple PDs are inserted into the developing cell plate, while during wall extension, more complex (branched) forms of PD are laid down. We show that complex PDs are derived from existing simple PDs in a pattern that is accelerated when leaves undergo the sink-source transition. Complex PDs are inserted initially at the three-way junctions between epidermal cells but develop most rapidly in the anisocytic complexes around stomata. For a quantitative analysis of complex PD formation, we established a high-throughput imaging platform and constructed PDQUANT, a custom algorithm that detected cell boundaries and PD numbers in different wall faces. For anticlinal walls, the number of complex PDs increased with increasing cell size, while for periclinal walls, the number of PDs decreased. Complex PD insertion was accelerated by up to threefold in response to salicylic acid treatment and challenges with mannitol. In a single 30-min run, we could derive data for up to 11k PDs from 3k epidermal cells. This facile approach opens the door to a large-scale analysis of the endogenous and exogenous factors that influence PD formation.

  11. Nuclear magnetic resonance study of charge transfer complex formation between Silver Nitrate and Benzylcyanide in Solvent Ethylene Glycol

    CERN Document Server

    Modarress, H

    2003-01-01

    The formation constant for charge transfer complexes between electron acceptor (AgNo sub 3) and electron donor benzylcyanide (C sub 6 H sub 5 -CH sub 2 -C ident to N) in solvent ethyleneglycol [(CH sub 2 OH) sub 2] has been evaluated by using the nuclear magnetic resonance chemical shifts of aromatic group of benzylcyanide measured against external references, tetramethylsilane, hexamethyldisilane and cyclohexane at 20 sup d ig sup C. The external referencing procedure eliminated the interference of internal reference in the course of complexation. The necessary bulk magnetic susceptibility corrections on the measured chemical shifts have been made. The solution nationalised and their effects on the formation constant have been considered and a new equation has been suggested to obtain the main ionic activity coefficient of AgNO sub 3 from nuclear magnetic resonance results. The mean ionic activity coefficient has been taken into account in the formation constant calculations. The results indicated that the a...

  12. Explicit solution format for complex-valued natural frequency of beam with R-shunted piezoelectric laminate transducer

    DEFF Research Database (Denmark)

    Høgsberg, Jan Becker; Cöent, Adrien Le

    2014-01-01

    Analysis and design of resistive shunt circuits for piezoelectric damping of beam structures is often based on a representation in terms of the single target vibration mode of the beam, neglecting spill-over effects from the out-of-bandwidth or residual vibration modes. In this article, a solution...... format is derived for the complex-valued natural frequency of the beam with a shunted piezoelectric laminate transducer, where the influence from the residual modes is taken into account by a quasi-static representation. This explicit solution format contains system parameters that directly represent....... The accuracy of the explicit frequency solution format is verified by comparison with numerical results. It is found that the complex-valued natural frequency of the first vibration mode of a beam with a piezoelectric laminate transducer shunted to a resistance is estimated with sufficient accuracy...

  13. Nudel is crucial for the WAVE complex assembly in vivo by selectively promoting subcomplex stability and formation through direct interactions

    Institute of Scientific and Technical Information of China (English)

    Shuang Wu; Li Ma; Yibo Wu; Rong Zeng; Xueliang Zhu

    2012-01-01

    The WAVE regulatory complex (WRC),consisting of WAVE,Sra,Nap,Abi,and HSPC300,activates the Arp2/3 complex to control branched actin polymerization in response to Rac activation.How the WRC is assembled in vivo is not clear.Here we show that Nudel,a protein critical for lamellipodia formation,dramatically stabilized the Sra1-Nap1-Abi1 complex against degradation in cells through a dynamic binding to Sra1,whereas its physical interaction with HSPC300 protected free HSPC300 from the proteasome-mediated degradation and stimulated the HSPC300-WAVE2 complex formation.By contrast,Nudel showed little or no interactions with the Sra1-Nap1-Abi1-WAVE2 and the Sra1-Nap1-Abi1-HSPC300 complexes as well as the mature WRC.Depletion of Nudel by RNAi led to general subunit degradation and markedly attenuated the levels of mature WRC.It also abolished the WRC-dependent actin polymerization in vitro and the Rac1-induced lamellipodial actin network formation during cell spreading.Therefore,Nudel is important for the early steps of the WRC assembly in vivo by antagonizing the instability of certain WRC subunits and subcomplexes.

  14. Mixed ligand complex formation of FeIII with boric acid and typical N-donor multidentate ligands

    Indian Academy of Sciences (India)

    G N Mukherjee; Ansuman Das

    2002-06-01

    Equilibrium study of the mixed ligand complex formation of FeIII with boric acid in the absence and in the presence of 2,2'-bipyridine, 1,10-phenanthroline, diethylenetriamine and triethylenetetramine (L) in different molar ratios provides evidence of formation of Fe(OH)2+, Fe(OH)$^{+}_{2}$, Fe(L)3+, Fe(H2BO4), Fe(OH)(H2BO4)-, Fe(OH)2(H2BO4)2-, Fe(L)(H2BO4) and Fe2(L)2(BO4)+ complexes. Fe(L)$^{3+}_{2}$, Fe(L)2(H2BO4) and Fe2(L)4(BO4)+ complexes are also indicated with 2,2'-bipyridine and 1,10-phenanthroline. Complex formation equilibria and stability constants of the complexes at 25 ± 0 × 1° C in aqueous solution at a fixed ionic strength, = 0.1 mol -3 (NaNO3) have been determined by potentiometric method.

  15. Protection of metal artefacts with the formation of metal-oxalates complexes by Beauveria bassiana.

    Directory of Open Access Journals (Sweden)

    Edith eJoseph

    2012-01-01

    Full Text Available Several fungi present high tolerance to toxic metals and some are able to transform metals into metal-oxalate complexes. In this study, the ability of Beauveria bassiana to produce copper oxalates was evaluated in vitro. Growth performance was tested on various copper-containing media. B. bassiana proved highly resistant to copper, tolerating concentrations of up to 20 g.L-1, and precipitating copper oxalates on all media tested. Chromatographic analyses showed that this species produced oxalic acid as sole metal chelator. The production of metal-oxalates can be used in the restoration and conservation of archaeological and modern metal artefacts. The production of copper-oxalates was confirmed directly using metallic pieces (both archaeological and modern. The conversion of corrosion products into copper oxalates was demonstrated as well. In order to assess whether the capability of B. bassiana to produce metal-oxalates could be applied to other metals, iron and silver were tested as well. Iron appears to be directly sequestered in the wall of the fungal hyphae forming oxalates and probably goethite. However, the formation of a homogeneous layer on the object is not yet optimal. Silver nitrate was extracellularly reduced into nanoparticles of elemental silver by an unknown mechanism. The production of copper oxalates is immediately applicable for the conservation of copper-based artefacts. For iron and silver this is not yet the case. However, the vast ability of B. bassiana to transform toxic metals using different immobilization mechanisms seems to offer considerable possibilities for industrial applications, such as the bioremediation of contaminated soils or the green synthesis of chemicals.

  16. Effect of pH and chemical mechanical planarization process conditions on the copper-benzotriazole complex formation

    Science.gov (United States)

    Cho, Byoung-Jun; Kim, Jin-Yong; Hamada, Satomi; Shima, Shohei; Park, Jin-Goo

    2016-06-01

    Benzotriazole (BTA) has been used to protect copper (Cu) from corrosion during Cu chemical mechanical planarization (CMP) processes. However, an undesirable Cu-BTA complex is deposited after Cu CMP processes and it should be completely removed at post-Cu CMP cleaning for next fabrication process. Therefore, it is very important to understand of Cu-BTA complex formation behavior for its applications such as Cu CMP and post-Cu CMP cleaning. The present study investigated the effect of pH and polisher conditions on the formation of Cu-BTA complex layers using electrochemical techniques (potentiodynamic polarization and electrochemical impedance spectroscopy) and the surface contact angle. The wettability was not a significant factor for the polishing interface, as no difference in the contact angles was observed for these processes. Both electrochemical techniques revealed that BTA had a unique advantage of long-term protection for Cu corrosion in an acidic condition (pH 3).

  17. In vivo analysis of formation and endocytosis of the Wnt/β-catenin signaling complex in zebrafish embryos.

    Science.gov (United States)

    Hagemann, Anja I H; Kurz, Jennifer; Kauffeld, Silke; Chen, Qing; Reeves, Patrick M; Weber, Sabrina; Schindler, Simone; Davidson, Gary; Kirchhausen, Tomas; Scholpp, Steffen

    2014-09-15

    After activation by Wnt/β-Catenin ligands, a multi-protein complex assembles at the plasma membrane as membrane-bound receptors and intracellular signal transducers are clustered into the so-called Lrp6-signalosome [Corrected]. However, the mechanism of signalosome formation and dissolution is yet not clear. Our imaging studies of live zebrafish embryos show that the signalosome is a highly dynamic structure. It is continuously assembled by Dvl2-mediated recruitment of the transducer complex to the activated receptors and partially disassembled by endocytosis. We find that, after internalization, the ligand-receptor complex and the transducer complex take separate routes. The Wnt-Fz-Lrp6 complex follows a Rab-positive endocytic path. However, when still bound to the transducer complex, Dvl2 forms intracellular aggregates. We show that this endocytic process is not only essential for ligand-receptor internalization but also for signaling. The μ2-subunit of the endocytic Clathrin adaptor Ap2 interacts with Dvl2 to maintain its stability during endocytosis. Blockage of Ap2μ2 function leads to Dvl2 degradation, inhibiton of signalosome formation at the plasma membrane and, consequently, reduction of signaling. We conclude that Ap2μ2-mediated endocytosis is important to maintain Wnt/β-catenin signaling in vertebrates.

  18. Mechanism of Formation of Copper(II) Chloro Complexes Revealed by Transient Absorption Spectroscopy and DFT/TDDFT Calculations.

    Science.gov (United States)

    Mereshchenko, Andrey S; Olshin, Pavel K; Karabaeva, Kanykey E; Panov, Maxim S; Wilson, R Marshall; Kochemirovsky, Vladimir A; Skripkin, Mikhail Yu; Tveryanovich, Yury S; Tarnovsky, Alexander N

    2015-07-16

    Copper(II) complexes are extremely labile with typical ligand exchange rate constants on the order of 10(6)-10(9) M(-1) s(-1). As a result, it is often difficult to identify the actual formation mechanism of these complexes. In this work, using UV-vis transient absorption when probing in a broad time range (20 ps to 8 μs) in conjunction with DFT/TDDFT calculations, we studied the dynamics and underlying reaction mechanisms of the formation of extremely labile copper(II) CuCl4(2-) chloro complexes from copper(II) CuCl3(-) trichloro complexes and chloride ions. These two species, produced via photochemical dissociation of CuCl4(2-) upon 420 nm excitation into the ligand-to-metal-charge-transfer electronic state, are found to recombine into parent complexes with bimolecular rate constants of (9.0 ± 0.1) × 10(7) and (5.3 ± 0.4) × 10(8) M(-1) s(-1) in acetonitrile and dichloromethane, respectively. In dichloromethane, recombination occurs via a simple one-step addition. In acetonitrile, where [CuCl3](-) reacts with the solvent to form a [CuCl3CH3CN](-) complex in less than 20 ps, recombination takes place via ligand exchange described by the associative interchange mechanism that involves a [CuCl4CH3CN](2-) intermediate. In both solvents, the recombination reaction is potential energy controlled.

  19. Complex formation between the uncoupler carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) and valinomycin in the presence of potassium.

    Science.gov (United States)

    O'Brien, T A; Nieva-Gomez, D; Gennis, R B

    1978-03-25

    Spectroscopic evidence is presented which indicates that the uncoupler carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) and the peptide antibiotic valinomycin form a complex in the presence of potassium. Complex formation has been observed both in aqueous and nonaqueous media. Several techniques have been used to indicate the existence of a complex in aqueous solution. In the presence of valinomycin and K+, the absorption spectrum of FCCP is significantly perturbed, and there is also a large induced circular dichroism signal. In addition, the previously characterized complex which forms between valinomycin, K+, and the fluorescent probe 8-anilino-1-naphthalene-sulfonate (ANS) in aqueous solution is apparently disrupted by the addition of FCCP. The result is an effective quenching of the fluorescence due to the bound probe as it is displaced from the valinomycin.K+ by the uncoupler. In a nonpolar solvent, the absorption spectrum of FCCP is also perturbed by valinomycin in the presence of K+, again indicating the formation of a complex. These data point to the importance of considering the role of valinomycin.K+.uncoupler complex in interpreting physiological or ion transport data in which these substances have been used together.

  20. Formation of oil complex collectors in the Pripyatskiy trough. Formirovaniye kollektorov neftenosnykh kompleksov Pripyatskogo progiba

    Energy Technology Data Exchange (ETDEWEB)

    Demidovich, L.A.

    1979-01-01

    Based on a comprehensive study of sedimentary formations, the formation of capacitance and filtering properties of rocks is examined. In order to clarify the conditions of formation and dispersal of rock-collectors of oil and gas, tectonic-lithological geochemical method is used. Results are used from multiple-factor analysis. A general classification of the collectors is given. It was compiled with regard for rock lithogenesis. Possibilities are examined for predicting collectors using the data of geochemical studies.

  1. THE FORMATION OF DESIGN AND ORGANIZATIONAL AND TECHNOLOGICAL DECISIONS OF THE CONSTRUCTION OF HIGH-RISE MULTIPURPOSE COMPLEXES

    Directory of Open Access Journals (Sweden)

    BOLSHAKOV V. I.

    2016-05-01

    Full Text Available Purpose. The formation of the many ways the construction of high-rise multipurpose complexes. Methodology. The formation of system implementation variants of creation and functioning of high-rise multipurpose complexes using combinatorial morphological analysis and synthesis. Findings. Many life cycle options of high-rise multipurpose complexes. Originality. The developed method of formation of organizational and technological solutions adapted to the conditions of the construction of high-rise multipurpose complexes, which provides the opportunity for multi-variant conditions, taking into account regulatory requirements for fire safety, insolation of buildings and premises, protection against noise and vibration, energy efficiency, infrastructure and population density of a residential district with a full range of institutions and enterprises of local significance, within existing resource constraints, to ensure the commissioning of objects with specified technical and economic characteristics. Practical value. The proposed model and the methodology allow to determine a rational variant of high-rise building according to specified criteria and constraints.

  2. Complex Explosive Phonolitic Volcanism From Tenerife, Canary Islands: the Diego Hernandez Formation

    Science.gov (United States)

    Olin, P. H.; Edgar, C. J.; Wolff, J. A.; Nichols, H. J.; Cas, R.; Marti, J.

    2001-12-01

    The Diego Hernandez Formation (DHF) consists of several phonolitic pyroclastic packages erupted between 0.53 and 0.196 Ma. Here we focus on the most intense period of DHF explosive phonolitic activity, from 0.32 - 0.28 Ma, during which three major plinian sequences with intraplinian ignimbrites, respectively the Aldea (0.320 +/- 0.008 Ma), Fasnia (0.309 +/- 0.012 Ma) and Poris Members (0.276 +/- 0.016 Ma) were emplaced. A minor disconformity, representing a pause of perhaps a few weeks' duration, separates lower and upper parts of the Fasnia Member. Volumes are difficult to estimate due to substantial offshore deposition, but each of the three has a minimum volume of a few cubic kilometers DRE. The dominant phonolite component in all three units shows broad chemical variations that suggest a similar magmatic lineage. However, details of trace element covariations do not support evolution of phonolite from a common parent, while the order of extraction of different compositions within a single eruption is complex. The Aldea and the lower Fasnia contain highly evolved phonolitic pumice (Zr up to 2,000 ppm), variably mixed with mafic and intermediate magmatic components. Plinian fall units in the upper Fasnia have little admixed mafic material yet are significantly less evolved than preceeding units (Zr = 850 - 1500 ppm), and show overall normal compositional zoning. However, highly evolved phonolite reappears towards the end of the Fasnia eruption sequence, and is more abundant in interbedded ignimbrites than in plinian fall units. The Poris Member contains phonolite similar to the least evolved compositions in the upper Fasnia, with a minor population of a much less differentiated phonolite (Zr = 600 - 650 ppm) that has little affinity with the the rest of the sequence, but resembles magmas erupted during a later DHF cycle. Both Poris phonolite types mingled with basaltic liquid. The repeated eruption of multiple felsic magmas with distinct trace element signatures

  3. TPR domain of NrfG mediates complex formation between heme lyase and formate-dependent nitrite reductase in Escherichia coli O157:H7.

    Science.gov (United States)

    Han, Dohyun; Kim, Kyunggon; Oh, Jongkil; Park, Jungeun; Kim, Youngsoo

    2008-02-15

    Escherichia coli synthesize C-type cytochromes only during anaerobic growth in media supplemented with nitrate and nitrite. The reduction of nitrate to ammonium in the periplasm of Escherichia coli involves two separate periplasmic enzymes, nitrate reductase and nitrite reductase. The nitrite reductase involved, NrfA, contains cytochrome C and is synthesized coordinately with a membrane-associated cytochrome C, NrfB, during growth in the presence of nitrite or in limiting nitrate concentrations. The genes NrfE, NrfF, and NrfG are required for the formate-dependent nitrite reduction pathway, which involves at least two C-type cytochrome proteins, NrfA and NrfB. The NrfE, NrfF, and NrfG genes (heme lyase complex) are involved in the maturation of a special C-type cytochrome, apocytochrome C (apoNrfA), to cytochrome C (NrfA) by transferring a heme to the unusual heme binding motif of the Cys-Trp-Ser-Cys-Lys sequence in apoNrfA protein. Thus, in order to further investigate the roles of NrfG in the formation of heme lyase complex (NrfEFG) and in the interaction between heme lyase complex and formate-dependent nitrite reductase (NrfA), we determined the crystal structure of NrfG at 2.05 A. The structure of NrfG showed that the contact between heme lyase complex (NrfEFG) and NrfA is accomplished via a TPR domain in NrfG which serves as a binding site for the C-terminal motif of NrfA. The portion of NrfA that binds to TPR domain of NrfG has a unique secondary motif, a helix followed by about a six-residue C-terminal loop (the so called "hook conformation"). This study allows us to better understand the mechanism of special C-type cytochrome assembly during the maturation of formate-dependent nitrite reductase, and also adds a new TPR binding conformation to the list of TPR-mediated protein-protein interactions.

  4. Unusual dimer formation of cyclometalated ruthenium NHC p-cymene complexes.

    Science.gov (United States)

    Schleicher, David; Tronnier, Alexander; Leopold, Hendrik; Borrmann, Horst; Strassner, Thomas

    2016-02-28

    We present the synthesis and structural characterization of novel ruthenium complexes containing C^C* cyclometalated N-heterocyclic carbene ligands, η(6)-arene (p-cymene) ligands and one bridging chlorine ion. Complexes of the general formula [Ru(p-cymene)(C^C*)Cl] were prepared via a one-pot synthesis using in situ transmetalation from the correspondent silver NHC complexes. These complexes react with sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaBAr(F)4) to form dinuclear complexes of the general structure [Ru(p-cymene)(C^C*)-μ-Cl-(p-cymene)(C^C*)Ru](+)[BAr(F)4](-). Solid-state structures confirm that the pseudo-tetrahedral coordination around the metal center with the η(6)-ligand aligned perpendicularly to the C^C* ligand and the i-Pr group "atop" is retained in the bimetallic complexes.

  5. Mixed-ligand complex formation equilibria of CuII with biguanide in presence of glycine as the auxiliary ligand

    Indian Academy of Sciences (India)

    Tannistha Roy Barman; G N Mukherjee

    2006-09-01

    Equilibrium study on the mixed ligand complex formation of CuII with biguanide(Bg) and glycine (HG), indicated the formation of the complexes: Cu(Bg)2+, Cu(Bg)$_{2}^{2+}$, Cu(Bg-H)(Bg)+, Cu(Bg-H)2, Cu(Bg)(OH)+, Cu(Bg-H)(OH); Cu(G)+, Cu(G)(OH), Cu(G)2; Cu(G)(Bg)+, Cu(G)(Bg-H); (G)Cu(Bg)Cu(G)2+, (G)Cu(Bg-H)Cu(G)+, and (G)Cu(Bg-2H)Cu(G). From the deprotonation constants of coordinated biguanide (Bg) in the complexes Cu(Bg)(OH)+, Cu(Bg-H)(Bg)+ and Cu(G)(Bg)+, the Lewis basicities of the coordinated ligand species (Bg-H)-, OH- and glycinate (G-) were found to be of the order: (Bg-H)- >> OH- > G-. Bridging (N1-N4, N2-N5) tetradentate mode of coordination by biguanide species Bg, (Bg-H)- and (Bg-2H)2- was indicated from the occurrence of biguanide-bridged dinuclear mixed ligand complexes (G)Cu(Bg)Cu(G)2+, (G)Cu(Bg-H)Cu(G)+, (G)Cu(Bg-2H)Cu(G) in the complexation equilibria.

  6. Spontaneous Binding of Molecular Oxygen at the Qo-Site of the bc1 Complex Could Stimulate Superoxide Formation

    DEFF Research Database (Denmark)

    Husen, Peter; Solov'yov, Ilia A

    2016-01-01

    to drive ATP synthesis. This molecular machinery, however, is suspected to be a source of superoxide, which is toxic to the cell, even in minuscular quantities, and believed to be a factor in aging. Through molecular dynamics simulations, we investigate here the migration of molecular oxygen in the bc1...... complex in order to identify possible reaction sites that could lead to superoxide formation. It is found, in particular, that oxygen penetrates spontaneously the Qo binding site of the bc1 complex in the presence of an intermediate semiquinone radical, thus making the Qo-site a strong candidate for being...... a center of superoxide production....

  7. Improvement of the absorption of /sup 3/H-cholecalciferol by formation of its cyclodextrin complex

    Energy Technology Data Exchange (ETDEWEB)

    Szejtli, J.; Gerloczy, A. (Biochemical Research Laboratory of Chinoin Pharmaceutical and Chemical Works, Budapest (Hungary)); Fonagy, A. (Orszagos Frederic Joliot-Curie Sugarbiologiai es Sugaregeszseguegyi Kutato Intezet, Budapest (Hungary))

    1983-02-01

    Oral administration of ..beta..-cyclodextrin inclusion complex of /sup 3/H-labelled vitamin D/sub 3/ (cholecalciferol) to rats resulted in significantly higher blood radioactivity as with the non-complexed vitamin. Difference in the first 90 minutes was 2.3-2.8 fold, and it remained significantly higher up to the 6th h. After 24 h there was no difference between the blood radioactivity of animals treated with complexed and with non-complexed vitamin D/sub 3/.

  8. HPV16E6-Dependent c-Fos Expression Contributes to AP-1 Complex Formation in SiHa Cells

    Directory of Open Access Journals (Sweden)

    Feixin Liang

    2011-01-01

    Full Text Available To date, the major role of HPV16E6 in cancer has been considered to be its ability to inhibit the p53 tumor-suppressor protein, thereby thwarting p53-mediated cytotoxic responses to cellular stress signals. Here, we show that HPV16E6-dependent c-fos oncogenic protein expression contributes to AP-1 complex formation under oxidative stress in SiHa cells (HPV16-positive squamous cell carcinoma of the cervix. In addition, we examined the role of HPV16E6 in TGF-α-induced c-fos expression and found that the c-fos protein expression induced by TGF-α is HPV16E6 dependent. Thus, our results provide the first evidence that HPV16E6 contributes to AP-1 complex formation after both ligand-dependent and independent EGFR activation, suggesting a new therapeutic approach to the treatment of HPV-associated tumors.

  9. Microbial adhesion and biofilm formation on microfiltration membranes: a detailed characterization using model organisms with increasing complexity.

    Science.gov (United States)

    Vanysacker, L; Denis, C; Declerck, P; Piasecka, A; Vankelecom, I F J

    2013-01-01

    Since many years, membrane biofouling has been described as the Achilles heel of membrane fouling. In the present study, an ecological assay was performed using model systems with increasing complexity: a monospecies assay using Pseudomonas aeruginosa or Escherichia coli separately, a duospecies assay using both microorganisms, and a multispecies assay using activated sludge with or without spiked P. aeruginosa. The microbial adhesion and biofilm formation were evaluated in terms of bacterial cell densities, species richness, and bacterial community composition on polyvinyldifluoride, polyethylene, and polysulfone membranes. The data show that biofouling formation was strongly influenced by the kind of microorganism, the interactions between the organisms, and the changes in environmental conditions whereas the membrane effect was less important. The findings obtained in this study suggest that more knowledge in species composition and microbial interactions is needed in order to understand the complex biofouling process. This is the first report describing the microbial interactions with a membrane during the biofouling development.

  10. Formation of inclusion complexes between high amylose starch and octadecyl ferulate via steam jet cooking

    Science.gov (United States)

    Amylose can form inclusion complexes with guest molecules and represents an interesting approach to deliver bioactive molecules. However, ferulic acid has been shown not to form single helical inclusion complexes with amylose. To overcome this problem a ferulic acid ester, octadecyl ferulate, posses...

  11. Volcanostratigraphic Sequences of Kebo-Butak Formation at Bayat Geological Field Complex, Central Java Province and Yogyakarta Special Province, Indonesia

    Directory of Open Access Journals (Sweden)

    Sri Mulyaningsih

    2016-08-01

    Full Text Available Bayat Complex is usually used as a work field for students of geology and other geosciences. The study area is located in the southern part of the Bayat Complex. Administratively, it belongs to Central Java Province and Yogyakarta Special Province. The lithology of Bayat is very complex, composed of various kinds of igneous, sedimentary, metamorphic, and volcanic rocks. Most of previous researchers interpreted Bayat as a melange complex constructed within a subduction zone. Kebo-Butak is one of formations that forms the Bayat field complex. The formation is composed of basalt, layers of pumice, tuff, shale, and carbonaceous tuff. Most of them are known as volcanic rocks. These imply that volcanic activities are more probable to construct the geology of Bayat rather than the subducted melange complex. The geological mapping, supported by geomorphology, petrology, stratigraphy, and geological structures, had been conducted in a comprehensive manner using the deduction-induction method. The research encounters basalt, black pumice, tuff with basaltic glasses fragments, zeolite, argilic clay, as well as feldspathic- and pumice tuff. Petrographically, the basalt is composed of labradorite, olivine, clinopyroxene, and volcanic glass. Black pumice and tuff contain prismatic clinopyroxene, granular olivine, and volcanic glasses. Feldspathic tuff and pumice tuff are crystal vitric tuff due to more abundant feldspar, quartz, and amphibole than volcanic glass. Zeolite comprises chlorite and altered glasses as deep sea altered volcanic rocks. The geologic structure is very complex, the major structures are normal faults with pyrite in it. There were two deep submarine paleovolcanoes namely Tegalrejo and Baturagung. The first paleovolcano erupted effusively producing basaltic sequence, while the second one erupted explosively ejecting feldspathic-rich pyroclastic material. The two paleovolcanoes erupted simultaneously and repeatedly.

  12. In vitro complex formation and inhibition of hepatic cytochrome P450 activity by different macrolides and tiamulin in goats and cattle

    NARCIS (Netherlands)

    Zweers-Zeilmaker, W.M.; Miert, A.S.J.P.A.M. van; Horbach, G.J.; Witkamp, R.F.

    1998-01-01

    In humans, clinically relevant drug–drug interactions occur with some macrolide antibiotics via the formation of stable metabolic intermediate (MI) complexes with enzymes of the cytochrome P4503A (CYP3A) subfamily. The formation of such complexes can result in a decreased biotransformation rate of s

  13. Opposite activation of the Hedgehog pathway in CD138+ plasma cells and CD138-CD19+ B cells identifies two subgroups of patients with multiple myeloma and different prognosis.

    Science.gov (United States)

    Martello, M; Remondini, D; Borsi, E; Santacroce, B; Procacci, M; Pezzi, A; Dico, F A; Martinelli, G; Zamagni, E; Tacchetti, P; Pantani, L; Testoni, N; Marzocchi, G; Rocchi, S; Zannetti, B A; Mancuso, K; Cavo, M; Terragna, C

    2016-09-01

    Hyperactivation of the Hedgehog (Hh) pathway, which controls refueling of multiple myeloma (MM) clones, might be critical to disease recurrence. Although several studies suggest the Hh pathway is activated in CD138- immature cells, differentiated CD138+ plasma cells might also be able to self-renew by producing themselves the Hh ligands. We studied the gene expression profiles of 126 newly diagnosed MM patients analyzed in both the CD138+ plasma cell fraction and CD138-CD19+ B-cell compartment. Results demonstrated that an Hh-gene signature was able to cluster patients in two subgroups characterized by the opposite Hh pathway expression in mature plasma cells and their precursors. Strikingly, patients characterized by Hh hyperactivation in plasma cells, but not in their B cells, displayed high genomic instability and an unfavorable outcome in terms of shorter progression-free survival (hazard ratio: 1.92; 95% confidence interval: 1.19-3.07) and overall survival (hazard ratio: 2.61; 95% confidence interval: 1.26-5.38). These results suggest that the mechanisms triggered by the Hh pathway ultimately led to identify a more indolent vs a more aggressive biological and clinical subtype of MM. Therefore, patient stratification according to their molecular background might help the fine-tuning of future clinical and therapeutic studies.

  14. Shatter Complex Formation in the Twin Craters Lava Flow, Zuni-Bandera Field, New Mexico

    Science.gov (United States)

    von Meerscheidt, H. C.; Bleacher, J. E.; Brand, B. D.; deWet, A.; Samuels, R.; Hamilton, C.; Garry, W. B.; Bandfield, J. L.

    2013-12-01

    . Prominent ';a';a channels travel around the bluff, leaving a 'wake' of uncovered ground on the downstream side. We interpret this shatter area to have been a branching tube network within an active sheet. The limestone bluff acted as an obstacle that caused a backup of lava within the tubes, driving episodes of shattering. The mounds likely represent earlier solidified sections between active, possibly braided, tube branches, which remained as mounds within the shatter area after the adjacent crust subsided. When lava broke out from the pressurized sheet-like lobe, it formed the ';a';a channels. This section of the flow field is interpreted using inferences from shatter ring formation, but is perhaps better termed a shatter sheet or shatter complex. This study has implications for understanding lava flow dynamics at constriction points, as well as the evolution and morphology of shatter rings.

  15. Oxo-group-14-element bond formation in binuclear uranium(V) Pacman complexes.

    Science.gov (United States)

    Jones, Guy M; Arnold, Polly L; Love, Jason B

    2013-07-29

    Simple and versatile routes to the functionalization of uranyl-derived U(V)-oxo groups are presented. The oxo-lithiated, binuclear uranium(V)-oxo complexes [{(py)3LiOUO}2(L)] and [{(py)3LiOUO}(OUOSiMe3)(L)] were prepared by the direct combination of the uranyl(VI) silylamide "ate" complex [Li(py)2][(OUO)(N")3] (N" = N(SiMe3)2) with the polypyrrolic macrocycle H4L or the mononuclear uranyl (VI) Pacman complex [UO2(py)(H2L)], respectively. These oxo-metalated complexes display distinct U-O single and multiple bonding patterns and an axial/equatorial arrangement of oxo ligands. Their ready availability allows the direct functionalization of the uranyl oxo group leading to the binuclear uranium(V) oxo-stannylated complexes [{(R3Sn)OUO}2(L)] (R = nBu, Ph), which represent rare examples of mixed uranium/tin complexes. Also, uranium-oxo-group exchange occurred in reactions with [TiCl(OiPr)3] to form U-O-C bonds [{(py)3LiOUO}(OUOiPr)(L)] and [(iPrOUO)2(L)]. Overall, these represent the first family of uranium(V) complexes that are oxo-functionalised by Group 14 elements.

  16. From N-alkylimidazole ligands at a rhenium center: ring opening or formation of NHC complexes.

    Science.gov (United States)

    Huertos, Miguel A; Pérez, Julio; Riera, Lucía; Menéndez-Velázquez, Amador

    2008-10-15

    Cationic rhenium tricarbonyl complexes with three N-alkylimidazole ligands undergo deprotonation of the central CH group upon reaction with 1 equiv of KN(SiMe3)2. For the tris(N-methylimidazole) complex, the metal fragment shifts from N to C, leaving an NHC complex with a nonsubstituted N atom. For compounds with at least one N-mesitylimidazole ligand, the intramolecular attack of the deprotonated carbon onto the central carbon of an N-mesitylimidazole ligand results in ring opening of the latter.

  17. THE ROLE OF EDUCATIONAL COMPLEXES IN THE IMPLEMENTATION OF THE PARTNERSHIP MODEL FORMATION OF THE NATIONAL QUALIFICATIONS FRAMEWORK

    Directory of Open Access Journals (Sweden)

    Kristina V. Gileva

    2015-01-01

    Full Text Available The aim of the study is to define potential of modern educational complexes in the field of formation of national system of qualifications on the basis of interpretation of procedures changes in regulation of social and labour relations. Methods. The methods involve analysis, generalisation, ordering and a technique of modelling of processes.Results. The authors describe key positions of the theory of the continuous education that provides rapprochement of requirements of employers with quality of vocational training and the content of educational process in the branch educational institutions. The possible contribution of educational complexes to creation of national system of qualifications and professional standards is considered. In this connection various forms of partnership of the given complexes with public authorities, public structures, and also employers are described.Scientific novelty. The concept of business competence characterising ability of system of vocational training is offered to satisfy the requirement of a labour market by means of active integration of educational, innovative and labour processes.Practical significance. The presented model of interaction of educational complexes and subjects of a labour market can be realised by working out of professional standards, creation of the expert centers and the innovative platforms intended to realisation of advisory activity on the basis of high schools; and also organizational-methodical support of processes of professional certification system formation. According to authors, this model will help to co-ordinate the content of professional and Federal State Educational Standards (FSES. 

  18. EXPRESSION OF SV40 Tag AND FORMATION Tag-p53 AND Tag-Rb COMPLEXES IN CHINESE BRAIN TUMORS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective: To investigate the expression of SV40 Tag andformation of Tag-p53 and Tag-Rb complexes in Chinese brain tumors. Methods: SV40 large tumor antigen (Tag) were investigated by immunoprecipitation, silver staining and Western blot in 65 cases of Chinese brain tumors and 8 cases of normal brain tissues. Tag-p53 and Tag-Rb complexes were screened by the same way in 20 and 15 Tag positive tumor tissues respectively. Results: Tag was found in all of 8 ependymomas and 2 choroid plexus papillomas, 90% (9/10) of pituitary adenomas, 73% (11/15) of astrocytomas, 70% (7/10) of meningiomas, 50% (4/8) of glioblastoma multiform, 33% (2/6) of medulloblastomas, 5 oligodendrogliomas, 1 pineocytoma and 8 normal brain tissues were negative for Tag. Tag-p53 complex was detected in all of 20 Tag positive tumors as well as Tag-Rb complex in all of 15 Tag positive tumors. Conclusion: SV40 Tag is not only expressed in human brain tumors, but also it can form specific complexes with tumor suppressors p53 and Rb. SV40 is correlated to human brain tumorigenesis. The inactivation of p53 and Rb due to the formation of Tag-p53 and Tag-Rb complexes is possibly an important mechanism in the etiopathogenesis of human brain tumors.

  19. Computational assessment of electron density in metallo-organic nickel pincer complexes for formation of PC bonds.

    Science.gov (United States)

    Eller, Joshua J; Downey, Karen

    2015-10-05

    Hydrophosphination is an atomically efficient method for introducing new carbon-phosphorous bonds in organic synthesis. New late-transition metal catalytic complexes are proposed to facilitate this process. These nickel-based complexes are analyzed using semiempirical (SE), Hartree-Fock (H-F), and density functional theory (DFT) models. H-F proves to be ineffective, while the SE approach has limited, qualitative use. DFT shows electron density at the metal center suitable for catalyzing bond formation in the proposed, reductive hydrophosphination mechanism. It also shows that the pincer complexes under investigation are relatively insensitive to solvent dielectric constant and to the chemical character of the monodentate ligand, both in terms of electron distribution and in terms of molecular orbital energies.

  20. Interaction of phosphorus dendrimers with HIV peptides—Fluorescence studies of nano-complexes formation

    Energy Technology Data Exchange (ETDEWEB)

    Ciepluch, Karol, E-mail: ciepluch@biol.uni.lodz.pl [Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska Street 141/143, 90-236 Lodz (Poland); Ionov, Maksim [Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska Street 141/143, 90-236 Lodz (Poland); Majoral, Jean-Pierre [Laboratoire de Chimie de Coordination du CNRS (LCC), 205 Route de Narbonne, F-31077 Toulouse cedex 4 (France); Muñoz-Fernández, Maria Angeles [Laboratorio InmunoBiología Molecular, Hospital General Universitario Gregorio Marañón, Madrid (Spain); Bryszewska, Maria [Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska Street 141/143, 90-236 Lodz (Poland)

    2014-04-15

    In this study, dendrimers emerge as an alternative approach for delivery of HIV peptides to dendritic cells. Gp160, NH-EIDNYTNTIYTLLEE-COOH; P24, NH-DTINEEAAEW-COOH and Nef, NHGMDDPEREVLEWRFDSRLAF-COOH peptides were complexed with two types of positively charged phosphorus-containing dendrimers (CPD). Fluorescence polarization, dynamic light scattering, transmission and electron microscopy (TEM) techniques were chosen to evaluate the dendriplexes stability. We were able to show that complexes were stable in time and temperature. This is crucial for using these peptide/dendrimer nano-complexes in a new vaccine against HIV-1 infection. -- Highlights: • The phosphorus dendrimers as nanocarriers of HIV-peptides are proposed. • The complexes of dendrimers and HIV-peptides were stable in time, temperature. • The results convince that phosphorus dendrimers could be consider as anti-HIV vaccine candidates.

  1. Rcf1 mediates cytochrome oxidase assembly and respirasome formation, revealing heterogeneity of the enzyme complex.

    Science.gov (United States)

    Vukotic, Milena; Oeljeklaus, Silke; Wiese, Sebastian; Vögtle, F Nora; Meisinger, Chris; Meyer, Helmut E; Zieseniss, Anke; Katschinski, Doerthe M; Jans, Daniel C; Jakobs, Stefan; Warscheid, Bettina; Rehling, Peter; Deckers, Markus

    2012-03-01

    The terminal enzyme of the mitochondrial respiratory chain, cytochrome oxidase, transfers electrons to molecular oxygen, generating water. Within the inner mitochondrial membrane, cytochrome oxidase assembles into supercomplexes, together with other respiratory chain complexes, forming so-called respirasomes. Little is known about how these higher oligomeric structures are attained. Here we report on Rcf1 and Rcf2 as cytochrome oxidase subunits in S. cerevisiae. While Rcf2 is specific to yeast, Rcf1 is a conserved subunit with two human orthologs, RCF1a and RCF1b. Rcf1 is required for growth in hypoxia and complex assembly of subunits Cox13 and Rcf2, as well as for the oligomerization of a subclass of cytochrome oxidase complexes into respirasomes. Our analyses reveal that the cytochrome oxidase of mitochondria displays intrinsic heterogeneity with regard to its subunit composition and that distinct forms of respirasomes can be formed by complex variants.

  2. Inhibition of PRL-2·CNNM3 Protein Complex Formation Decreases Breast Cancer Proliferation and Tumor Growth.

    Science.gov (United States)

    Kostantin, Elie; Hardy, Serge; Valinsky, William C; Kompatscher, Andreas; de Baaij, Jeroen H F; Zolotarov, Yevgen; Landry, Melissa; Uetani, Noriko; Martínez-Cruz, Luis Alfonso; Hoenderop, Joost G J; Shrier, Alvin; Tremblay, Michel L

    2016-05-13

    The oncogenic phosphatase of regenerating liver 2 (PRL-2) has been shown to regulate intracellular magnesium levels by forming a complex through an extended amino acid loop present in the Bateman module of the CNNM3 magnesium transporter. Here we identified highly conserved residues located on this amino acid loop critical for the binding with PRL-2. A single point mutation (D426A) of one of those critical amino acids was found to completely disrupt PRL-2·human Cyclin M 3 (CNNM3) complex formation. Whole-cell voltage clamping revealed that expression of CNNM3 influenced the surface current, whereas overexpression of the binding mutant had no effect, indicating that the binding of PRL-2 to CNNM3 is important for the activity of the complex. Interestingly, overexpression of the CNNM3 D426A-binding mutant in cancer cells decreased their ability to proliferate under magnesium-deprived situations and under anchorage-independent growth conditions, demonstrating a PRL-2·CNNM3 complex-dependent oncogenic advantage in a more stringent environment. We further confirmed the importance of this complex in vivo using an orthotopic xenograft breast cancer model. Finally, because molecular modeling showed that the Asp-426 side chain in CNNM3 buries into the catalytic cavity of PRL-2, we showed that a PRL inhibitor could abrogate complex formation, resulting in a decrease in proliferation of human breast cancer cells. In summary, we provide evidence that this fundamental regulatory aspect of PRL-2 in cancer cells could potentially lead to broadly applicable and innovative therapeutic avenues.

  3. Terminal axonal arborization and synaptic bouton formation critically rely on abp1 and the arp2/3 complex.

    Directory of Open Access Journals (Sweden)

    Nicole Koch

    Full Text Available Neuronal network formation depends on properly timed and localized generation of presynaptic as well as postsynaptic structures. Although of utmost importance for understanding development and plasticity of the nervous system and neurodegenerative diseases, the molecular mechanisms that ensure the fine-control needed for coordinated establishment of pre- and postsynapses are still largely unknown. We show that the F-actin-binding protein Abp1 is prominently expressed in the Drosophila nervous system and reveal that Abp1 is an important regulator in shaping glutamatergic neuromuscular junctions (NMJs of flies. STED microscopy shows that Abp1 accumulations can be found in close proximity of synaptic vesicles and at the cell cortex in nerve terminals. Abp1 knock-out larvae have locomotion defects and underdeveloped NMJs that are characterized by a reduced number of both type Ib synaptic boutons and branches of motornerve terminals. Abp1 is able to indirectly trigger Arp2/3 complex-mediated actin nucleation and interacts with both WASP and Scar. Consistently, Arp2 and Arp3 loss-of-function also resulted in impairments of bouton formation and arborization at NMJs, i.e. fully phenocopied abp1 knock-out. Interestingly, neuron- and muscle-specific rescue experiments revealed that synaptic bouton formation critically depends on presynaptic Abp1, whereas the NMJ branching defects can be compensated for by restoring Abp1 functions at either side. In line with this presynaptic importance of Abp1, also presynaptic Arp2 and Arp3 are crucial for the formation of type Ib synaptic boutons. Interestingly, presynaptic Abp1 functions in NMJ formation were fully dependent on the Arp2/3 complex, as revealed by suppression of Abp1-induced synaptic bouton formation and branching of axon terminals upon presynaptic Arp2 RNAi. These data reveal that Abp1 and Arp2/3 complex-mediated actin cytoskeletal dynamics drive both synaptic bouton formation and NMJ branching. Our

  4. Siderophile element systematics of IAB complex iron meteorites: New insights into the formation of an enigmatic group

    Science.gov (United States)

    Worsham, Emily A.; Bermingham, Katherine R.; Walker, Richard J.

    2016-09-01

    Siderophile trace element abundances and the 187Re-187Os isotopic systematics of the metal phases of 58 IAB complex iron meteorites were determined in order to investigate formation processes and how meteorites within chemical subgroups may be related. Close adherence of 187Re-187Os isotopic data of most IAB iron meteorites to a primordial isochron indicates that the siderophile elements of most members of the complex remained closed to elemental disturbance soon after formation. Minor, presumably late-stage open-system behavior, however, is observed in some members of the sLM, sLH, sHL, and sHH subgroups. The new siderophile element abundance data are consistent with the findings of prior studies suggesting that the IAB subgroups cannot be related to one another by any known crystallization process. Equilibrium crystallization, coupled with crystal segregation, solid-liquid mixing, and subsequent fractional crystallization can account for the siderophile element variations among meteorites within the IAB main group (MG). The data for the sLM subgroup are consistent with equilibrium crystallization, combined with crystal segregation and mixing. By contrast, the limited fractionation of siderophile elements within the sLL subgroup is consistent with metal extraction from a chondritic source with little subsequent processing. The limited data for the other subgroups were insufficient to draw robust conclusions about crystallization processes involved in their formation. Collectively, multiple formational processes are represented in the IAB complex, and modeling results suggest that fractional crystallization within the MG may have been a more significant process than has been previously recognized.

  5. A First Step Towards Synthesising Rubrics and Video for the Formative Assessment of Complex Skills

    NARCIS (Netherlands)

    Ackermans, Kevin; Rusman, Ellen; Brand-Gruwel, Saskia; Specht, Marcus

    2016-01-01

    Abstract. The performance objectives used for the formative assessment of com- plex skills are generally set through text-based analytic rubrics[1]. Moreover, video modeling examples are a widely applied method of observational learning, providing students with context-rich modeling examples of comp

  6. A Case Study of Teacher Personal Practice Assessment Theories and Complexities of Implementing Formative Assessment

    Science.gov (United States)

    Box, Cathy; Skoog, Gerald; Dabbs, Jennifer M.

    2015-01-01

    The value and effectiveness of formative assessment in the classroom has gained an increasing amount of attention during the past decade, especially since the publication of seminal work by Black and Wiliam titled "Assessment and Classroom Learning." Since that time, there has been a renewed interest in describing and evaluating teacher…

  7. Professional Motivation Formation of Future Specialists under the Conditions of Regional Educational Complex

    Science.gov (United States)

    Kargina, Elena Mikhaylovna

    2015-01-01

    Motivation plays the leading role in the organization of the personality structure. It is a driving force of the activity. Motivation accounts for the behavior and activity and has a great impact on professional self-determination and person's satisfaction with the work. The problem of professional motivation formation of a future specialist is…

  8. Encapsulation of nabumetone by means of -drug: ({beta}-cyclodextrin){sub 2}:polyvinylpyrrolidone ternary complex formation

    Energy Technology Data Exchange (ETDEWEB)

    Valero, Margarita [Departamento de Quimica Fisica, Facultad de Farmacia, Universidad de Salamanca, Salamanca (Spain)]. E-mail: mvalero@usal.es; Tejedor, Javier [Departamento de Quimica Fisica, Facultad de Farmacia, Universidad de Salamanca, Salamanca (Spain); Rodriguez, Licesio J. [Departamento de Quimica Fisica, Facultad de Farmacia, Universidad de Salamanca, Salamanca (Spain)

    2007-10-15

    The aim of the present study was to investigate the effect of the presence of the water-soluble polymer polyvinylpyrrolidone (PVP) MW=24,000 g/mol, on the complexing of the anti-inflammatory drug nabumetone, with {beta}-cyclodextrin ({beta}-CD). The data show that the polymer interacts with the free nabumetone and with the nabumetone:{beta}-CD inclusion complex, in both cases with a stoichiometry of 1:1. The interaction constants are 1.3x10{sup 4} M{sup -1} and 1.6x10{sup 4} M{sup -1}, respectively. The presence of PVP, changes the drug:cyclodextrin interaction, a nabumetone:({beta}-CD){sub 2}:PVP complex being formed. In addition, the presence of PVP, produces a strong increase in the global binding constant, {beta} {sub 2}=(22.12{+-}0.22)x10{sup 6} M{sup -2} at 1% PVP. In the ternary complex, the nabumetone is wrapped at both ends for the {beta}-CD. In this complex the polymer seems to act as a bridge between both {beta}-CD molecules that bind the nabumetone.

  9. Formation of a Bazooka-Stardust complex is essential for plasma membrane polarity in epithelia.

    Science.gov (United States)

    Krahn, Michael P; Bückers, Johanna; Kastrup, Lars; Wodarz, Andreas

    2010-09-01

    Apical-basal polarity in Drosophila melanogaster epithelia depends on several evolutionarily conserved proteins that have been assigned to two distinct protein complexes: the Bazooka (Baz)-PAR-6 (partitioning defective 6)-atypical protein kinase C (aPKC) complex and the Crumbs (Crb)-Stardust (Sdt) complex. These proteins operate in a functional hierarchy, in which Baz is required for the proper subcellular localization of all other proteins. We investigated how these proteins interact and how this interaction is regulated. We show that Baz recruits Sdt to the plasma membrane by direct interaction between the Postsynaptic density 95/Discs large/Zonula occludens 1 (PDZ) domain of Sdt and a region of Baz that contains a phosphorylation site for aPKC. Phosphorylation of Baz causes the dissociation of the Baz-Sdt complex. Overexpression of a nonphosphorylatable version of Baz blocks the dissociation of Sdt from Baz, causing phenotypes very similar to those of crb and sdt mutations. Our findings provide a molecular mechanism for the phosphorylation-dependent interaction between the Baz-PAR-3 and Crb complexes during the establishment of epithelial polarity.

  10. G protein activation by G protein coupled receptors: ternary complex formation or catalyzed reaction?

    Science.gov (United States)

    Roberts, David J; Waelbroeck, Magali

    2004-09-01

    G protein coupled receptors catalyze the GDP/GTP exchange on G proteins, thereby activating them. The ternary complex model, designed to describe agonist binding in the absence of GTP, is often extended to G protein activation. This is logically unsatisfactory as the ternary complex does not accumulate when G proteins are activated by GTP. Extended models taking into account nucleotide binding exist, but fail to explain catalytic G protein activation. This review puts forward an enzymatic model of G protein activation and compares its predictions with the ternary complex model and with observed receptor phenomenon. This alternative model does not merely provide a new set of formulae but leads to a new philosophical outlook and more readily accommodates experimental observations. The ternary complex model implies that, HRG being responsible for efficient G protein activation, it should be as stable as possible. In contrast, the enzyme model suggests that although a limited stabilization of HRG facilitates GDP release, HRG should not be "too stable" as this might trap the G protein in an inactive state and actually hinder G protein activation. The two models also differ completely in the definition of the receptor "active state": the ternary complex model implies that the active state corresponds to a single active receptor conformation (HRG); in contrast, the catalytic model predicts that the active receptor state is mobile, switching smoothly through various conformations with high and low affinities for agonists (HR, HRG, HRGGDP, HRGGTP, etc.).

  11. The formation of hydrophilic Np(IV) complexes and their potential application in nuclear fuel reprocessing

    Energy Technology Data Exchange (ETDEWEB)

    May, I.; Taylor, R.J.; Brown, G. [British Nuclear Fuels Ltd., Sellafield (United Kingdom)

    1998-06-12

    A series of organic ligands have been screened for their effectiveness as complexants for Np(IV) in a neptunium rejection stage of an advanced PUREX process. Four of these species, formohydroxamic acid, acetohydroxamic acid, glycolic acid and pyruvic acid, readily form hydrophilic complexes with Np(IV) and can strip the actinide from 30% TBP/OK (30% tributylphosphate in odourless kerosene) into nitric acid. Near infra-red spectroscopy has been used to monitor Np(IV) complexation in nitric acid. Distribution experiments have been undertaken between nitric acid and 30% TBP/OK to examine the effect of ligand and nitric acid concentration on Np(IV) stripping. Finally, it has been shown that the extractability of U(VI) is unaffected by the presence of these ligands and all can be used to selectively strip Np(IV) from a U(VI) product stream in an advanced PUREX process. (orig.) 11 refs.

  12. Considerable fluorescence enhancement upon supramolecular complex formation between berberine and p-sulfonated calixarenes

    Science.gov (United States)

    Megyesi, Mónika; Biczók, László

    2006-06-01

    Remarkably strong binding of berberine to 4-sulfonatocalix[8]arene was found in aqueous solution, which led to fluorescence quantum yield increase of a factor about 40 at pH 2. The hypsochromic shift of the fluorescence maximum implied that berberine sensed less polar microenvironment when confined to SCX8. The stability of the supramolecular complex significantly diminished when sulfocalixarenes of smaller ring size served as host compounds but the pH affected the association strength to a much lesser extent. All berberine complexes proved to be barely fluorescent at pH 12.2 because of excited state quenching by the hosts via electron transfer.

  13. In vivo protein interactions and complex formation in the Pectobacterium atrosepticum subtype I-F CRISPR/Cas System.

    Directory of Open Access Journals (Sweden)

    Corinna Richter

    Full Text Available Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR and their associated proteins (Cas; CRISPR associated are a bacterial defense mechanism against extra-chromosomal elements. CRISPR/Cas systems are distinct from other known defense mechanisms insofar as they provide acquired and heritable immunity. Resistance is accomplished in multiple stages in which the Cas proteins provide the enzymatic machinery. Importantly, subtype-specific proteins have been shown to form complexes in combination with small RNAs, which enable sequence-specific targeting of foreign nucleic acids. We used Pectobacterium atrosepticum, a plant pathogen that causes soft-rot and blackleg disease in potato, to investigate protein-protein interactions and complex formation in the subtype I-F CRISPR/Cas system. The P. atrosepticum CRISPR/Cas system encodes six proteins: Cas1, Cas3, and the four subtype specific proteins Csy1, Csy2, Csy3 and Cas6f (Csy4. Using co-purification followed by mass spectrometry as well as directed co-immunoprecipitation we have demonstrated complex formation by the Csy1-3 and Cas6f proteins, and determined details about the architecture of that complex. Cas3 was also shown to co-purify all four subtype-specific proteins, consistent with its role in targeting. Furthermore, our results show that the subtype I-F Cas1 and Cas3 (a Cas2-Cas3 hybrid proteins interact, suggesting a protein complex for adaptation and a role for subtype I-F Cas3 proteins in both the adaptation and interference steps of the CRISPR/Cas mechanism.

  14. In vivo protein interactions and complex formation in the Pectobacterium atrosepticum subtype I-F CRISPR/Cas System.

    Science.gov (United States)

    Richter, Corinna; Gristwood, Tamzin; Clulow, James S; Fineran, Peter C

    2012-01-01

    Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and their associated proteins (Cas; CRISPR associated) are a bacterial defense mechanism against extra-chromosomal elements. CRISPR/Cas systems are distinct from other known defense mechanisms insofar as they provide acquired and heritable immunity. Resistance is accomplished in multiple stages in which the Cas proteins provide the enzymatic machinery. Importantly, subtype-specific proteins have been shown to form complexes in combination with small RNAs, which enable sequence-specific targeting of foreign nucleic acids. We used Pectobacterium atrosepticum, a plant pathogen that causes soft-rot and blackleg disease in potato, to investigate protein-protein interactions and complex formation in the subtype I-F CRISPR/Cas system. The P. atrosepticum CRISPR/Cas system encodes six proteins: Cas1, Cas3, and the four subtype specific proteins Csy1, Csy2, Csy3 and Cas6f (Csy4). Using co-purification followed by mass spectrometry as well as directed co-immunoprecipitation we have demonstrated complex formation by the Csy1-3 and Cas6f proteins, and determined details about the architecture of that complex. Cas3 was also shown to co-purify all four subtype-specific proteins, consistent with its role in targeting. Furthermore, our results show that the subtype I-F Cas1 and Cas3 (a Cas2-Cas3 hybrid) proteins interact, suggesting a protein complex for adaptation and a role for subtype I-F Cas3 proteins in both the adaptation and interference steps of the CRISPR/Cas mechanism.

  15. Pentosan polysulfate increases affinity between ADAMTS-5 and TIMP-3 through formation of an electrostatically driven trimolecular complex.

    Science.gov (United States)

    Troeberg, Linda; Mulloy, Barbara; Ghosh, Peter; Lee, Meng-Huee; Murphy, Gillian; Nagase, Hideaki

    2012-04-01

    The semi-synthetic sulfated polysaccharide PPS (pentosan polysulfate) increases affinity between the aggrecan-degrading ADAMTSs (adamalysins with thrombospondin motifs) and their endogenous inhibitor, TIMP (tissue inhibitor of metalloproteinases)-3. In the present study we demonstrate that PPS mediates the formation of a high-affinity trimolecular complex with ADAMTS-5 and TIMP-3. A TIMP-3 mutant that lacks extracellular-matrix-binding ability was insensitive to this affinity increase, and truncated forms of ADAMTS-5 that lack the Sp (spacer) domain had reduced PPS-binding ability and sensitivity to the affinity increase. PPS molecules composed of 11 or more saccharide units were 100-fold more effective than those of eight saccharide units, indicating the involvement of extended or multiple protein-interaction sites. The formation of a high-affinity trimolecular complex was completely abolished in the presence of 0.4 M NaCl. These results suggest that PPS enhances the affinity between ADAMTS-5 and TIMP-3 by forming electrostatically driven trimolecular complexes under physiological conditions.

  16. Concomitant Carboxylate and Oxalate Formation From the Activation of CO2 by a Thorium(III) Complex

    Science.gov (United States)

    Formanuik, Alasdair; Ortu, Fabrizio; Inman, Christopher J.; Kerridge, Andrew; Castro, Ludovic

    2016-01-01

    Abstract Improving our comprehension of diverse CO2 activation pathways is of vital importance for the widespread future utilization of this abundant greenhouse gas. CO2 activation by uranium(III) complexes is now relatively well understood, with oxo/carbonate formation predominating as CO2 is readily reduced to CO, but isolated thorium(III) CO2 activation is unprecedented. We show that the thorium(III) complex, [Th(Cp′′)3] (1, Cp′′={C5H3(SiMe3)2‐1,3}), reacts with CO2 to give the mixed oxalate‐carboxylate thorium(IV) complex [{Th(Cp′′)2[κ2‐O2C{C5H3‐3,3′‐(SiMe3)2}]}2(μ‐κ2:κ2‐C2O4)] (3). The concomitant formation of oxalate and carboxylate is unique for CO2 activation, as in previous examples either reduction or insertion is favored to yield a single product. Therefore, thorium(III) CO2 activation can differ from better understood uranium(III) chemistry. PMID:27714966

  17. Fluorimetric determination of diosmin and hesperidin in combined dosage forms and in plasma through complex formation with terbium

    Directory of Open Access Journals (Sweden)

    Dalia Mohamed

    2013-06-01

    Full Text Available A sensitive and simple fluorimetric method was developed for the determination of diosmin and hesperidin. The proposed method involves the formation of ternary complex with Tb3+ in the presence of Tris buffer. The fluorescence quenching of Tb3+ at 549 and 494 nm (λex at 275 and 248 nm due to the complex formation was quantitatively measured for diosmin and hesperidin, respectively. The reaction conditions and the fluorescence spectral properties of the complexes have been investigated. Under the described conditions, the proposed method was applicable over the concentration range (4.93 × 10−6–1.81 × 10−5 mol and (3.28 × 10−6–1.64 × 10−5 mol with mean percentage recoveries 100.22 ± 0.89 and 99.13 ± 0.72 for diosmin and hesperidin, respectively. The proposed method was applied successfully for the determination of studied drugs in bulk powder, dosage forms and plasma samples. The results obtained by applying the described method were statistically analyzed and compared with those obtained by applying a reported method. The method was validated according to ICH recommendations.

  18. The Non-canonical Tetratricopeptide Repeat (TPR) Domain of Fluorescent (FLU) Mediates Complex Formation with Glutamyl-tRNA Reductase.

    Science.gov (United States)

    Zhang, Min; Zhang, Feilong; Fang, Ying; Chen, Xuemin; Chen, Yuhong; Zhang, Wenxia; Dai, Huai-En; Lin, Rongcheng; Liu, Lin

    2015-07-10

    The tetratricopeptide repeat (TPR)-containing protein FLU is a negative regulator of chlorophyll biosynthesis in plants. It directly interacts through its TPR domain with glutamyl-tRNA reductase (GluTR), the rate-limiting enzyme in the formation of δ-aminolevulinic acid (ALA). Delineation of how FLU binds to GluTR is important for understanding the molecular basis for FLU-mediated repression of synthesis of ALA, the universal tetrapyrrole precursor. Here, we characterize the FLU-GluTR interaction by solving the crystal structures of the uncomplexed TPR domain of FLU (FLU(TPR)) at 1.45-Å resolution and the complex of the dimeric domain of GluTR bound to FLU(TPR) at 2.4-Å resolution. Three non-canonical TPR motifs of each FLU(TPR) form a concave surface and clamp the helix bundle in the C-terminal dimeric domain of GluTR. We demonstrate that a 2:2 FLU(TPR)-GluTR complex is the functional unit for FLU-mediated GluTR regulation and suggest that the formation of the FLU-GluTR complex prevents glutamyl-tRNA, the GluTR substrate, from binding with this enzyme. These results also provide insights into the spatial regulation of ALA synthesis by the membrane-located FLU protein.

  19. Formation of competitive potential of the machine-building complex of the region

    Directory of Open Access Journals (Sweden)

    Oleg Ivanovich Botkin

    2014-03-01

    Full Text Available The article describes the features of competitive potential of regional machine-building complex in a globalized world economy. The purpose of the research is the development of theoretically reasonable economic basis of the machine-building complex considering  the  features of business in the conditions of the WTO. In the work, the hypothesis of a special role of the external economic factors locates in development of the enterprises of regional industrial complexes. The study of the theoretical provisions defining the development of the region revealed the factors determining influence of the international trade agreements on spatial localization of the industry. The main attention is paid to an analytical assessment of the current state and the trends, which have developed in the period of post-crisis economic recovery. Analysis of the main indicators of attractiveness has revealed the weak position of local industrial enterprises in the WTO. The directions of strengthening of the competitive capacity of the local industrial enterprises are defined. The obtained results allow us to increase the sustainability of the industry by means of effective management mechanism improvements and to create favorable operating conditions of a machine-building complex of the region

  20. Development of excretion stimulating techniques for radioactive materials via complex formation

    Energy Technology Data Exchange (ETDEWEB)

    Takaya, Haruo; Uchiumi, Akira; Takatsu, Akiko [National Inst. of Materials and Chemical Research, Tsukuba, Ibaraki (Japan)

    1998-02-01

    With an aim to establish an effective technique to eliminate RI metals incorporated into an organism through rapid excretion out of the body, development of complex forming agents which fill the following conditions was attempted; (1) it is able to form a stable complex with RI metal ion targetted, (2) the cell toxicity is low and (3) it has no effects on the physiologically essential metal ions. As such complex-foaming agents which allow to excrete Ni and Cd incorporated, several sugar-formazan derivatives were synthesized by introducing various functional groups into 4-0-{alpha}-D-glucopyranosyl {beta}-D-glucopyranose, a reducing disaccharide. First, maltose-phenylhydrazine was synthesized from phenylhydrazine and maltose, and its solution in ethylacetate-pyridine was added with diazotized o-aminophenol. Thus, maltose-formazan was obtained. Six kinds of formazan derivatives were able to foam the respective complexes with Co, Ni, Cu, Zn and Cd, but not with Mg, Ca, Fe, etc., suggesting that these derivatives are usable as an excreting agent for Ni and Cd. (M.N.)

  1. Viewbrics: Formative Assessment of Complex Skills with Video-Enhanced Rubrics (VER) in Dutch Secondary Education

    NARCIS (Netherlands)

    Rusman, Ellen; Nadolski, Rob; Boon, Jo; Ackermans, Kevin

    2016-01-01

    To learn complex skills, like collaboration, learners need to acquire a concrete and consistent mental model of what it means to master this skill. If learners know their current mastery level and know their targeted mastery level, they can better determine their subsequent learning activities. Rubr

  2. Imaging inclusion complex formation in starch granules using confocal laser scanning microscopy

    NARCIS (Netherlands)

    Manca, Marianna; Woortman, Albert J. J.; Loos, Katja; Loi, Maria A.

    2015-01-01

    The tendency of amylose to form inclusion complexes with guest molecules has been an object of wide interest due to its fundamental role in food processing. Here we investigated the features of starch granules from several botanical sources using confocal laser scanning microscopy (CLSM) and uncover

  3. ParB Partition Proteins: Complex Formation and Spreading at Bacterial and Plasmid Centromeres

    Directory of Open Access Journals (Sweden)

    Barbara Funnell

    2016-08-01

    Full Text Available In bacteria, active partition systems contribute to the faithful segregation of both chromosomes and low-copy-number plasmids. Each system depends on a site-specific DNA binding protein to recognize and assemble a partition complex at a centromere-like site, commonly called parS. Many plasmid and all chromosomal centromere-binding proteins are dimeric helix-turn-helix DNA binding proteins, which are commonly named ParB. Although the overall sequence conservation among ParBs is not high, the proteins share similar domain and functional organization, and they assemble into similar higher-order complexes. In vivo, ParBs spread; that is, DNA binding extends away from the parS site into the surrounding nonspecific DNA, a feature that reflects higher-order complex assembly. ParBs bridge and pair DNA at parS and nonspecific DNA sites. ParB dimers interact with each other via flexible conformations of an N-terminal region. This review will focus on the properties of the HTH centromere-binding protein, in light of recent experimental evidence and models that are adding to our understanding of how these proteins assemble into large and dynamic partition complexes at and around their specific DNA sites.

  4. Kolmogorov complexity of epithelial pattern formation: the role of regulatory network configuration.

    Science.gov (United States)

    Flann, Nicholas S; Mohamadlou, Hamid; Podgorski, Gregory J

    2013-05-01

    The tissues of multicellular organisms are made of differentiated cells arranged in organized patterns. This organization emerges during development from the coupling of dynamic intra- and intercellular regulatory networks. This work applies the methods of information theory to understand how regulatory network structure both within and between cells relates to the complexity of spatial patterns that emerge as a consequence of network operation. A computational study was performed in which undifferentiated cells were arranged in a two dimensional lattice, with gene expression in each cell regulated by identical intracellular randomly generated Boolean networks. Cell-cell contact signalling between embryonic cells is modeled as coupling among intracellular networks so that gene expression in one cell can influence the expression of genes in adjacent cells. In this system, the initially identical cells differentiate and form patterns of different cell types. The complexity of network structure, temporal dynamics and spatial organization is quantified through the Kolmogorov-based measures of normalized compression distance and set complexity. Results over sets of random networks that operate in the ordered, critical and chaotic domains demonstrate that: (1) ordered and critical networks tend to create the most information-rich patterns; (2) signalling configurations in which cell-to-cell communication is non-directional mostly produce simple patterns irrespective of the internal network domain; and (3) directional signalling configurations, similar to those that function in planar cell polarity, produce the most complex patterns, but only when the intracellular networks function in non-chaotic domains.

  5. [A complexity analysis of Chinese herbal property theory: the multiple formations of herbal property].

    Science.gov (United States)

    Jin, Rui; Zhang, Bing

    2012-11-01

    Chinese herbal property theory (CHPT) is the fundamental characteristic of Chinese materia medica different from modern medicines. It reflects the herbal properties associated with efficacy and formed the early framework of four properties and five flavors in Shennong's Classic of Materia Medica. After the supplement and improvement of CHPT in the past thousands of years, it has developed a theory system including four properties, five flavors, meridian entry, direction of medicinal actions (ascending, descending, floating and sinking) and toxicity. However, because of the influence of philosophy about yin-yang theory and five-phase theory and the difference of cognitive approach and historical background at different times, CHPT became complex. One of the complexity features was the multiple methods for determining herbal property, which might include the inference from herbal efficacy, the thought of Chinese Taoist School and witchcraft, the classification thinking according to manifestations, etc. Another complexity feature was the multiselection associations between herbal property and efficacy, which indicated that the same property could be inferred from different kinds of efficacy. This paper analyzed these complexity features and provided the importance of cognitive approaches and efficacy attributes corresponding to certain herbal property in the study of CHPT.

  6. Association of phycoerythrin and phycocyanin: in vitro formation of a functional energy transferring phycobilisome complex of Porphyridium sordidum

    Energy Technology Data Exchange (ETDEWEB)

    Lipschultz, C.A.; Gantt, E.

    1981-01-01

    Functional in vitro association and dissociation of a phycobiliprotein complex, isolated from phycobilisomes of the red alga Porphyridium sordidum, were studied. The complex contained large bangiophyceaen phycoerythrin and cyanophytan phycocyanin in an equimolar ratio and had absorption maxima at 625, 567, and 550 nm and a shoulder at 495 nm. Emission at 655 nm (with excitation at 545 nm) from phycocyanin indicated functional coupling. The complex was stable over a wide buffer concentration range, and, notably, it was maximally stable in low phosphate, <0.01 M, unlike the phycobilisomes, which dissociate at this concentration. Its molecular weight was estimated to be ca. 510 000, and by electron microscopy it was seen to consist of two units of similar size. The complex in 0.1 M phosphate was separated on a sucrose gradient into a homogeneous phycoerythrin band and a spectrally heterogeneous phycocyanin band. In vitro association of phycoerythrin and phycocyanin resulted in a complex with the same absorbance, emission, sedimentation, and molar pigment ratio as those of the native complex. The spectrally heterogeneous phycocyanin fractions from the dissociation gradient varied in the degree of association with phycoerythrin. Phycocyanin fractions absorbing from 622 to 633 nm exhibited high associability (>70%), whereas those with maxima at 617-620 nm had low associability (<30%). The presence of a 30 000 molecular weight polypeptide accompanied high associability, where it was ca. 2-fold more prominent. It is suggested that this polypeptide is involved in complex formation and could serve either in the stabilization of the conformational state of cyanophytan phycocyanin or as a direct linker between phycobiliproteins.

  7. Supramolecular Formation via Hydrogen Bonding in Copper and Nickel Complexes with 2-Hydroxynicotinic Acid

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Two complexes, Cu(HnicO)2 1 and Ni(HnicO)2(H2O)2 2 (H2nicO = 2-hydroxy- nicolinic acid), were synthesized by hydrothermal reactions and structurally characterized. Complex 1 crystallizes in monoclinic, space group P21/n, with a = 8.314(7), b = 6.275(4), c = 11.283(7) (A), β = 98.32(3)°, V = 582.5(7) (A)3, Z = 2, Mr = 339.74, Dc = 1.937 g/cm3, F(000) = 342, μ = 1.908 mm-1, S = 1.097, the final R = 0.0284 and wR = 0.0781 for 1177 observed reflections with I>2σ(I). Complex 2 crystallizes in monoclinic, space group P21/c, with a = 7.438(5), b = 12.22(1), c = 7.537(5) (A), β = 100.07(3)°, V = 674.3(8) (A)3, Z = 2, Mr = 370.95, Dc = 1.827 g/cm3, F(000) = 380, μ = 1.487 mm-1, S = 1.041, the final R = 0.0335 and wR = 0.0779 for 1202 observed reflections with I>2σ(I). There are extended 3D framework structures in complexes 1 and 2 due to the N-H…O and C-H…O hydrogen bonds. The copper atom in 1 has square planar coordination, while the nickel atom in 2 adopts octahedral coordination geometry. The TG curve shows that complex 2 is stable in solid state to 150 ℃.

  8. Initial formation of an indigenous crop complex in eastern North America at 3800 B.P.

    Science.gov (United States)

    Smith, Bruce D; Yarnell, Richard A

    2009-04-21

    Although geneticists and archaeologists continue to make progress world-wide in documenting the time and place of the initial domestication of a growing number of plants and animals, far less is known regarding the critically important context of coalescence of various species into distinctive sets or complexes of domesticates in each of the world's 10 or more independent centers of agricultural origin. In this article, the initial emergence of a crop complex is described for one of the best-documented of these independent centers, eastern North America (ENA). Before 4000 B.P. there is no indication of a crop complex in ENA, only isolated evidence for single indigenous domesticate species. By 3800 B.P., however, at least 5 domesticated seed-bearing plants formed a coherent complex in the river valley corridors of ENA. Accelerator mass spectrometer radiocarbon dates and reanalysis of archaeobotanical assemblages from a short occupation of the Riverton Site in Illinois documents the contemporary cultivation at 3800 B.P. of domesticated bottle gourd (Lagenaria siceraria), marshelder (Iva annua var. macrocarpa), sunflower (Helianthus annuus var. macrocarpus), and 2 cultivated varieties of chenopod (Chenopodium berlandieri), as well as the possible cultivation of Cucurbita pepo squash and little barley (Hordeum pusillum). Rather than marking either an abrupt developmental break or a necessary response to population-packing or compressed resource catchments, the coalescence of an initial crop complex in ENA appears to reflect an integrated expansion and enhancement of preexisting hunting and gathering economies that took place within a context of stable long-term adaptation to resource-rich river valley settings.

  9. CR2-mediated activation of the complement alternative pathway results in formation of membrane attack complexes on human B lymphocytes

    DEFF Research Database (Denmark)

    Nielsen, C H; Marquart, H V; Prodinger, W M;

    2001-01-01

    Normal human B lymphocytes activate the alternative pathway of complement via complement receptor type 2 (CR2, CD21), that binds hydrolysed C3 (iC3) and thereby promotes the formation of a membrane-bound C3 convertase. We have investigated whether this might lead to the generation of a C5...... convertase and consequent formation of membrane attack complexes (MAC). Deposition of C3 fragments and MAC was assessed on human peripheral B lymphocytes in the presence of 30% autologous serum containing 4.4 mM MgCl2/20 mM EGTA, which abrogates the classical pathway of complement without affecting...... the alternative pathway. Blockade of the CR2 ligand-binding site with the monoclonal antibody FE8 resulted in 56 +/- 13% and 71 +/- 9% inhibition of the C3-fragment and MAC deposition, respectively, whereas the monoclonal antibody HB135, directed against an irrelevant CR2 epitope, had no effect. Blockade...

  10. Chabazite and dolomite formation in a dolocrete profile: An example of a complex alkaline paragenesis in Lanzarote, Canary Islands

    Science.gov (United States)

    Alonso-Zarza, Ana M.; Bustamante, Leticia; Huerta, Pedro; Rodríguez-Berriguete, Álvaro; Huertas, María José

    2016-05-01

    This paper studies the weathering and soil formation processes operating on detrital sediments containing alkaline volcanic rock fragments of the Mirador del Río dolocrete profile. The profile consists of a lower horizon of removilised weathered basalts, an intermediate red sandy mudstones horizon with irregular carbonate layers and a topmost horizon of amalgamated carbonate layers with root traces. Formation occurred in arid to semiarid climates, giving place to a complex mineralogical association, including Mg-carbonates and chabazite, rarely described in cal/dolocretes profiles. Initial vadose weathering processes occurred in the basalts and in directly overlying detrital sediments, producing (Stage 1) red-smectites and dolomicrite. Dominant phreatic (Stage 2) conditions allowed precipitation of coarse-zoned dolomite and chabazite filling porosities. In Stages 3 and 4, mostly pedogenic, biogenic processes played an important role in dolomite and calcite accumulation in the profile. Overall evolution of the profile and its mineralogical association involved initial processes dominated by alteration of host rock, to provide silica and Mg-rich alkaline waters, suitable for chabazite and dolomite formation, without a previous carbonate phase. Dolomite formed both abiogenically and biogenically, but without a previous carbonate precursor and in the absence of evaporites. Dominance of calcite towards the profile top is the result of Mg/Ca decrease in the interstitial meteoric waters due to decreased supply of Mg from weathering, and increased supply of Ca in aeolian dust. Meteoric origin of the water is confirmed by C and O isotope values, which also indicate lack of deep sourced CO2. The dolocrete studied and its complex mineral association reveal the complex interactions that occur at surface during weathering and pedogenesis of basalt-sourced rocks.

  11. Complexity

    CERN Document Server

    Gershenson, Carlos

    2011-01-01

    The term complexity derives etymologically from the Latin plexus, which means interwoven. Intuitively, this implies that something complex is composed by elements that are difficult to separate. This difficulty arises from the relevant interactions that take place between components. This lack of separability is at odds with the classical scientific method - which has been used since the times of Galileo, Newton, Descartes, and Laplace - and has also influenced philosophy and engineering. In recent decades, the scientific study of complexity and complex systems has proposed a paradigm shift in science and philosophy, proposing novel methods that take into account relevant interactions.

  12. On Magnetic Activity Band Overlap, Interaction, and the Formation of Complex Solar Active Regions

    CERN Document Server

    McIntosh, Scott W

    2014-01-01

    Recent work has revealed an phenomenological picture of the how the $\\sim$11-year sunspot cycle of Sun arises. The production and destruction of sunspots is a consequence of the latitudinal-temporal overlap and interaction of the toroidal magnetic flux systems that belong to the 22-year magnetic activity cycle and are rooted deep in the Sun's convective interior. We present a conceptually simple extension of this work, presenting a hypothesis on how complex active regions can form as a direct consequence of the intra- and extra-hemispheric interaction taking place in the solar interior. Furthermore, during specific portions of the sunspot cycle we anticipate that those complex active regions may be particular susceptible to profoundly catastrophic breakdown---producing flares and coronal mass ejections of most severe magnitude.

  13. Electromediated formation of DNA complexes with cell membranes and its consequences for gene delivery

    CERN Document Server

    Escoffre, Jean-Michel; Favard, Cyril; Teissié, Justin; Dean, David S; Rols, Marie-Pierre

    2011-01-01

    Electroporation is a physical method to induce the uptake of therapeutic drugs and DNA, by eukaryotic cells and tissues. The phenomena behind electro-mediated membrane permeabilization to plasmid DNA have been shown to be significantly more complex than those for small molecules. Small molecules cross the permeabilized membrane by diffusion whereas plasmid DNA first interacts with the electropermeabilized part of the cell surface, forming localized aggregates. The dynamics of this process is still poorly understood because direct observations have been limited to scales of the order of seconds. Here, cells are electropermeabilized in the presence of plasmid DNA and monitored with a temporal resolution of 2 ms. This allows us to show that during the first pulse application, plasmid complexes, or aggregates, start to form at distinct sites on the cell membrane. FRAP measurements show that the positions of these sites are remarkably immobile during the application of further pluses. A theoretical model is propos...

  14. Almost enclosed buckyball joints: synthesis, complex formation, and computational simulations of pentypticene-extended tribenzotriquinacene.

    Science.gov (United States)

    Henne, Stefan; Bredenkötter, Björn; Alaghemandi, Mohammad; Bureekaew, Sareeya; Schmid, Rochus; Volkmer, Dirk

    2014-12-01

    We report the synthesis of a tribenzotriquinacene-based (TBTQ) receptor (3) for C60 fullerene, which is extended by pentiptycene moieties to provide an almost enclosed concave ball bearing. The system serves as a model for a self-assembling molecular rotor with a flexible and adapting stator. Unexpectedly, nuclear magnetic resonance spectroscopic investigations reveal a surprisingly low complex stability constant of K1 =213±37 M(-1) for [C60 ⊂3], seemingly inconsistent with the previously reported TBTQ systems. Molecular dynamics (MD) simulations have been conducted for three different [C60 ⊂TBTQ] complexes to resolve this. Because of the dominating dispersive interactions, the binding energies increase with the contact area between guest and host, however, only for rigid host structures. By means of free-energy calculations with an explicit solvent model it can be shown that the novel flexible TBTQ receptor 3 binds weakly because of hampering entropic contributions.

  15. Volumetric analysis of complex lunar craters - Implications for basin ring formation

    Science.gov (United States)

    Hale, W. S.; Grieve, R. A. F.

    1982-01-01

    The crater to basin transition in complex lunar craters is characterized by combining morphological and volumetric analyses of their central peaks with subsurface data from terrestrial complex impact structures which suggest that the amount of uplifted material, as judged from its depth of origin, continues to increase with increasing rim diameter. This latter phenomenon implies that a redistribution of uplifted material away from a centralized peak may occur in the larger craters. The morphological and volumetric changes described occur over a rim diameter range of 51-80 km, which is considerably lower than the previously proposed range for the crater to basin transition of 140-175 km. Evidence is given in support of a crater to basin transition which begins at 51-80 km, and is characterized by a relative reduction in central peak volume and a development of rings of floor roughening which may be precursors of peak ring development.

  16. Highly active and selective catalysis of copper diphosphine complexes for the transformation of carbon dioxide into silyl formate.

    Science.gov (United States)

    Motokura, Ken; Kashiwame, Daiki; Takahashi, Naoki; Miyaji, Akimitsu; Baba, Toshihide

    2013-07-22

    Copper diphosphine complexes have been found to be highly active and selective homogeneous catalysts for the hydrosilylation of CO2. The structure of the phosphine ligands strongly affects their catalytic activity. Turnover number (TON) reaches 70,000 after 24 hours with 1,2-bis(diisopropylphosphino)benzene as a ligand under 1 atmosphere of CO2. (1)H and (13)C NMR spectra, carried out under the reaction conditions, showed the reaction mechanism through insertion of CO2 into Cu-H to afford Cu/formate species.

  17. Formation of complement membrane attack complex in mammalian cerebral cortex evokes seizures and neurodegeneration.

    Science.gov (United States)

    Xiong, Zhi-Qi; Qian, Weihua; Suzuki, Katsuaki; McNamara, James O

    2003-02-01

    The complement system consists of >30 proteins that interact in a carefully regulated manner to destroy invading bacteria and prevent the deposition of immune complexes in normal tissue. This complex system can be activated by diverse mechanisms proceeding through distinct pathways, yet all converge on a final common pathway in which five proteins assemble into a multimolecular complex, the membrane attack complex (MAC). The MAC inserts into cell membranes to form a functional pore, resulting in ion flux and ultimately osmotic lysis. Immunohistochemical evidence of the MAC decorating neurons in cortical gray matter has been identified in multiple CNS diseases, yet the deleterious consequences, if any, of MAC deposition in the cortex of mammalian brain in vivo are unknown. Here we demonstrate that the sequential infusion of individual proteins of the membrane attack pathway (C5b6, C7, C8, and C9) into the hippocampus of awake, freely moving rats induced both behavioral and electrographic seizures as well as cytotoxicity. The onset of seizures occurred during or shortly after the infusion of C8/C9. Neither seizures nor cytotoxicity resulted from the simultaneous infusion of all five proteins premixed in vitro. The requirement for the sequential infusion of all five proteins together with the temporal relationship of seizure onset to infusions of C8/C9 implies that the MAC was formed in vivo and triggered both seizures and cytotoxicity. Deposition of the complement MAC in cortical gray matter may contribute to epileptic seizures and cell death in diverse diseases of the human brain.

  18. Extractive Spectrophotometric Determination of Fluconazole by Ion-pair Complex Formation with Bromocresol Green

    Institute of Scientific and Technical Information of China (English)

    JALALI,Fahimeh; RAJABI,Mohammad J.

    2007-01-01

    An extraction-spectrophotometric method for the determination of trace amounts of fluconazole was described.Fluconazole was effectively extracted as a 1 : 1 ion-pair complex with bromocresole green (BCG) at pH 3.0 into chloroform, followed by spectrophotometric determination at 420 nm. Beer's law was obeyed over the range of 4-procedure was applied to the determination of fluconazole in pharmaceutical preparations as well as its recovery from a blood serum sample.

  19. Formation and characterization of stable fluorescent complexes between neutral conjugated polymers and cyclodextrins.

    Science.gov (United States)

    Martínez-Tomé, Maria José; Esquembre, Rocío; Mallavia, Ricardo; Mateo, C Reyes

    2013-01-01

    Solubilisation and stabilization of conjugated polymers, CPs, in aqueous media remains a challenge for many researches trying to extend the biological and environmental applications of this kind of polymers. A number of different alternatives have been considered to address this problem, which are mostly based on the enhancement of the macromolecule polarity, by appending hydrophilic side chains on the polymer backbone. In this work we have investigated a new strategy in which water solubilization is reached by external addition of classical cyclodextrins (α-, β- and γ-CDs) to a solution of non-polar CPs. This strategy allows working with such polymers eliminating the need to synthesize new water-soluble species. The polymer selected for the study was poly-[9,9-bis(6'-bromohexyl-2,7-fluoren-dyil)-co-alt-(benzene-1,4-diy)], PFPBr(2), a polyfluorene previously synthesized in our laboratory. Results show that PFPBr(2) forms fluorescent complexes in aqueous media with β-CD and γ-CD, and much less efficiently with α-CD, probably due to the small size of its cavity. The new PFPBr(2)/CD complexes are stable in time and in a large range of pH, however, at high concentration and temperature, they tend to aggregate and precipitate. In order to increase stabilization and minimize polymer aggregation, complexes were encapsulated inside the pores of silica glasses fabricated using the sol-gel process, obtaining transparent and fluorescent hybrid matrices which were stable in time and temperature. In addition, immobilization of the complexes allows an easy manipulation of the material, thus offering promising applications in the development of biological and chemical sensors.

  20. In vivo formation of complex microvessels lined by human endothelial cells in an immunodeficient mouse

    OpenAIRE

    2000-01-01

    We have identified conditions for forming cultured human umbilical vein endothelial cells (HUVEC) into tubes within a three-dimensional gel that on implantation into immunoincompetent mice undergo remodeling into complex microvessels lined by human endothelium. HUVEC suspended in mixed collagen/fibronectin gels organize into cords with early lumena by 24 h and then apoptose. Twenty-hour constructs, s.c. implanted in immunodeficient mice, display HUVEC-lined thin-walled microvessels within the...

  1. Stable complex formation of CENP-B with the CENP-A nucleosome.

    Science.gov (United States)

    Fujita, Risa; Otake, Koichiro; Arimura, Yasuhiro; Horikoshi, Naoki; Miya, Yuta; Shiga, Tatsuya; Osakabe, Akihisa; Tachiwana, Hiroaki; Ohzeki, Jun-ichirou; Larionov, Vladimir; Masumoto, Hiroshi; Kurumizaka, Hitoshi

    2015-05-26

    CENP-A and CENP-B are major components of centromeric chromatin. CENP-A is the histone H3 variant, which forms the centromere-specific nucleosome. CENP-B specifically binds to the CENP-B box DNA sequence on the centromere-specific repetitive DNA. In the present study, we found that the CENP-A nucleosome more stably retains human CENP-B than the H3.1 nucleosome in vitro. Specifically, CENP-B forms a stable complex with the CENP-A nucleosome, when the CENP-B box sequence is located at the proximal edge of the nucleosome. Surprisingly, the CENP-B binding was weaker when the CENP-B box sequence was located in the distal linker region of the nucleosome. This difference in CENP-B binding, depending on the CENP-B box location, was not observed with the H3.1 nucleosome. Consistently, we found that the DNA-binding domain of CENP-B specifically interacted with the CENP-A-H4 complex, but not with the H3.1-H4 complex, in vitro. These results suggested that CENP-B forms a more stable complex with the CENP-A nucleosome through specific interactions with CENP-A, if the CENP-B box is located proximal to the CENP-A nucleosome. Our in vivo assay also revealed that CENP-B binding in the vicinity of the CENP-A nucleosome substantially stabilizes the CENP-A nucleosome on alphoid DNA in human cells.

  2. Structure of ultradisperse nickel particles produced by the thermolysis of nickel formate-monoethanol amine complexes

    Energy Technology Data Exchange (ETDEWEB)

    Khvorov, M.M.; Dudchenko, A.K.; Khimchenko, IU.I.

    1986-05-01

    Histograms of the size distribution of ultradisperse nickel particles produced by the thermolysis of amine complexes are plotted using dark-field and light-field electron microscopy data. It is found that the size distribution can be adequately approximated by logarithmically probabilistic functions. The ultradisperse nickel particles feature several types of structure, i.e., faceted stable single crystals coated by an organic film, small aggregates of such crystals, large stable globules, and hexahedral and trihedral crystals. 8 references.

  3. Unusual C-C bond cleavage in the formation of amine-bis(phenoxy) group 4 benzyl complexes: Mechanism of formation and application to stereospecific polymerization

    KAUST Repository

    Gowda, Ravikumar R.

    2014-08-11

    Group 4 tetrabenzyl compounds MBn4 (M = Zr, Ti), upon protonolysis with an equimolar amount of the tetradentate amine-tris(phenol) ligand N[(2,4-tBu2C6H2(CH 2)OH]3 in toluene from -30 to 25 °C, unexpectedly lead to amine-bis(phenoxy) dibenzyl complexes, BnCH2N[(2,4- tBu2C6H2(CH2)O] 2MBn2 (M = Zr (1), Ti (2)) in 80% (1) and 75% (2) yields. This reaction involves an apparent cleavage of the >NCH2-ArOH bond (loss of the phenol in the ligand) and formation of the >NCH 2-CH2Bn bond (gain of the benzyl group in the ligand). Structural characterization of 1 by X-ray diffraction analysis confirms that the complex formed is a bis(benzyl) complex of Zr coordinated by a newly derived tridentate amine-bis(phenoxy) ligand arranged in a mer configuration in the solid state. The abstractive activation of 1 and 2 with B(C6F 5)3·THF in CD2Cl2 at room temperature generates the corresponding benzyl cations {BnCH2N[(2,4- tBu2C6H2(CH2)O] 2MBn(THF)}+[BnB(C6F5) 3]- (M = Zr (3), Ti, (4)). These cationic complexes, along with their analogues derived from (imino)phenoxy tri- and dibenzyl complexes, [(2,6-iPr2C6H3)N=C(3,5- tBu2C6H2)O]ZrBn3 (5) and [2,4-Br2C6H2(O)(6-CH2(NC 5H9))CH2N=CH(2-adamantyl-4-MeC 6H2O)]ZrBn2 (6), have been found to effectively polymerize the biomass-derived renewable β-methyl-α-methylene- γ-butyrolactone (βMMBL) at room temperature into the highly stereoregular polymer PβMMBL with an isotacticity up to 99% mm. A combined experimental and DFT study has yielded a mechanistic pathway for the observed unusual C-C bond cleavage in the present protonolysis reaction between ZrBn4 and N[(2,4-tBu2C 6H2(CH2)OH]3 for the formation of complex 1, which involves the benzyl radical and the Zr(III) species, resulting from thermal and photochemical decomposition of ZrBn4, followed by a series of reaction sequences consisting of protonolysis, tautomerization, H-transfer, oxidation, elimination, and radical coupling. © 2014 American Chemical Society.

  4. Use of spectroscopic technique to develop a reagent for Mo(VI) utilizing micellar effects on complex formation

    Science.gov (United States)

    Taşcioğlu, Sülin; Kaki, E.; Taşcioğlu, Senay

    2012-09-01

    Ultraviolet and visible spectral properties of aqueous solutions of molybdenum(VI) (Mo), gallic acid (GA), Lalanine (Ala), and L-Phenylalanine (Phe), and of their binary and ternary solutions were investigated in the absence and presence of anionic, cationic, and nonionic surfactant micelles. Evaluation of the spectra in a comparative way revealed that both Ala and Phe form ternary complexes with Mo and GA. The formation of a quaternary complex between Mo, GA, Phe, and cetyltrimethylammonium bromide at pH 4.5 provided a reagent system with a strikingly high sensitivity (1.2•106 l/(mol•cm)) for use in the spectrophotometric determination of Mo. A mechanism of micellar effects was discussed in terms of the substrate molecular charge and hydrophobicity, and rationalized on the basis of the spectral data obtained above and below the isoelectric pH of the amino acids.

  5. Formation and annealing of metastable (interstitial oxygen)-(interstitial carbon) complexes in n- and p-type silicon

    CERN Document Server

    Makarenko, L F; Lastovskii, S B; Murin, L I; Moll, M; Pintilie, I

    2014-01-01

    It is shown experimentally that, in contrast to the stable configuration of (interstitial carbon)-(interstitial oxygen) complexes (CiOi), the corresponding metastable configuration (CiOi{*}) cannot be found in n-Si based structures by the method of capacitance spectroscopy. The rates of transformation CiOi{*} -> CiOi are practically the same for both n- and p-Si with a concentration of charge carriers of no higher than 10(13) cm(-3). It is established that the probabilities of the simultaneous formation of stable and metastable configurations of the complex under study in the case of the addition of an atom of interstitial carbon to an atom of interstitial oxygen is close to 50\\%. This is caused by the orientation dependence of the interaction potential of an atom of interstitial oxygen with an interstitial carbon atom, which diffuses to this oxygen atom.

  6. Expression of a kinase-dead form of CPK33 involved in florigen complex formation causes delayed flowering.

    Science.gov (United States)

    Kawamoto, Nozomi; Endo, Motomu; Araki, Takashi

    2015-01-01

    Regulation of flowering time is crucial for reproductive success of plants. FLOWERING LOCUS T (FT) protein is a central component of florigen and forms a ternary complex with 14-3-3 and FD, a basic leucine zipper transcription factor, in the shoot apex and promotes flowering. This complex formation requires phosphorylation of threonine residue at position 282 of FD. A calcium-dependent protein kinase CPK33 is responsible for the phosphorylation. However, possibly due to functional redundancy among calcium-dependent protein kinases, impact of the loss of CPK33 reported in the previous study was rather limited. Here, we report that expression of a kinase-dead form of CPK33 caused a clear delayed-flowering phenotype, supporting for an important role of CPK33 in florigen function through FD phosphorylation.

  7. Axonal transport and neurodegenerative disease: vesicle-motor complex formation and their regulation

    Directory of Open Access Journals (Sweden)

    Anderson EN

    2014-03-01

    Full Text Available Eric N Anderson,* Joseph A White II,* Shermali GunawardenaDepartment of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY, USA *These authors contributed equally to this work Abstract: The process of axonal transport serves to move components over very long distances on microtubule tracks in order to maintain neuronal viability. Molecular motors – kinesin and dynein – are essential for the movement of neuronal cargoes along these tracks; defects in this pathway have been implicated in the initiation or progression of some neurodegenerative diseases, suggesting that this process may be a key contributor in neuronal dysfunction. Recent work has led to the identification of some of the motor-cargo complexes, adaptor proteins, and their regulatory elements in the context of disease proteins. In this review, we focus on the assembly of the amyloid precursor protein, huntingtin, mitochondria, and the RNA-motor complexes and discuss how these may be regulated during long-distance transport in the context of neurodegenerative disease. As knowledge of these motor-cargo complexes and their involvement in axonal transport expands, insight into how defects in this pathway contribute to the development of neurodegenerative diseases becomes evident. Therefore, a better understanding of how this pathway normally functions has important implications for early diagnosis and treatment of diseases before the onset of disease pathology or behavior. Keywords: kinesin, dynein, amyloid precursor protein, huntingtin, microtubules

  8. Facile formation and redox of benzoxazole-2-thiolate-bridged dinuclear Pt(II/III) complexes.

    Science.gov (United States)

    Wang, Zhe; Jiang, Lu; Liu, Zhi-Pan; Gan, C R Raymond; Liu, Zhaolin; Zhang, Xin-Hai; Zhao, Jin; Hor, T S Andy

    2012-10-28

    Reaction of [Pt(L)(μ-Cl)](2) (L = ppy (2-phenylpyridine) or bzq (benzo[h]quinoline)) with 2-mercaptobenzoxazole (NOSH) and NaOAc in THF at r.t. yields the dinuclear Pt(II) d(8)-d(8) complexes [Pt(2)L(2)(μ-NOS-κN,S)(2)] (L = ppy, 1; L = bzq, 2) and the Pt(III) d(7)-d(7) complexes [Pt(2)(ppy)(2)(μ-NOS-κN,S)(2)(NOS-κS)(2)] (L = ppy, 3; L = bzq, 4) in one pot. The C,N-cyclometalated ligand is chelating whereas the N,S-donating benzoxazole-2-thiolates doubly bridge the two metal centers. The Pt···Pt separations of 3.0204(3) and 2.9726(8) Å in 1 and 2 contract to 2.685(1) Å in 3 and 2.6923(3) Å in 4, respectively, when two S-bound thiolate ligands coordinate trans- to the Pt···Pt axis. However, cyclometalation is preserved and there is minimum perturbation of the bridging ligands. Complexes 3 and 4 can be also obtained by oxidative addition of the thiolate ligand. In the presence of NaBH(4), 3 and 4 can be reduced to 1 and 2, respectively. At r.t., 1 and 2 exhibit intense orange-red luminescence at 625 nm and 631 nm, respectively. The electrochemical properties of 1-4 have been also discussed.

  9. Formation of oxygen complexes in controlled atmosphere at surface of doped glassy carbon

    Indian Academy of Sciences (India)

    Aleksandra A Perić-Grujić; Tatjana M Vasiljević; Olivera M Nešković; Miomir V Veljković; Zoran V Laušević; Mila D Laušević

    2006-10-01

    The effects of boron and phosphorus incorporation in phenolic resin precursor to the oxidation resistance of glassy carbon have been studied. In order to reveal the nature and composition of the oxygen complexes formed at the surface of doped glassy carbon, under controlled atmosphere, the surface of the samples was cleaned under vacuum up to 1273 K. Specific functional groups, subsequently formed under dry CO2 or O2 atmosphere on the surface of boron-doped and phosphorus-doped glassy carbon samples, were examined using the temperature-programmed desorption method combined with mass spectrometric analysis. Characterization of surface properties of undoped and doped samples has shown that in the presence of either boron or phosphorus heteroatoms, a lower amount of oxygen complexes formed after CO2 exposure, while, typically, higher amount of oxygen complexes formed after O2 exposure. It has been concluded that the surface of undoped glassy carbon has a greater affinity towards CO2, while in the presence of either boron or phosphorus heteroatoms, the glassy carbon surface affinity becomes greater towards O2, under experimental conditions.

  10. Predicting permeability from the characteristic relaxation time and intrinsic formation factor of complex conductivity spectra

    Science.gov (United States)

    Revil, A.; Binley, A.; Mejus, L.; Kessouri, P.

    2015-08-01

    Low-frequency quadrature conductivity spectra of siliclastic materials exhibit typically a characteristic relaxation time, which either corresponds to the peak frequency of the phase or the quadrature conductivity or a typical corner frequency, at which the quadrature conductivity starts to decrease rapidly toward lower frequencies. This characteristic relaxation time can be combined with the (intrinsic) formation factor and a diffusion coefficient to predict the permeability to flow of porous materials at saturation. The intrinsic formation factor can either be determined at several salinities using an electrical conductivity model or at a single salinity using a relationship between the surface and quadrature conductivities. The diffusion coefficient entering into the relationship between the permeability, the characteristic relaxation time, and the formation factor takes only two distinct values for isothermal conditions. For pure silica, the diffusion coefficient of cations, like sodium or potassium, in the Stern layer is equal to the diffusion coefficient of these ions in the bulk pore water, indicating weak sorption of these couterions. For clayey materials and clean sands and sandstones whose surface have been exposed to alumina (possibly iron), the diffusion coefficient of the cations in the Stern layer appears to be 350 times smaller than the diffusion coefficient of the same cations in the pore water. These values are consistent with the values of the ionic mobilities used to determine the amplitude of the low and high-frequency quadrature conductivities and surface conductivity. The database used to test the model comprises a total of 202 samples. Our analysis reveals that permeability prediction with the proposed model is usually within an order of magnitude from the measured value above 0.1 mD. We also discuss the relationship between the different time constants that have been considered in previous works as characteristic relaxation time, including

  11. Formative assessment and design of a complex clinical decision support tool for pulmonary embolism.

    Science.gov (United States)

    Khan, Sundas; McCullagh, Lauren; Press, Anne; Kharche, Manish; Schachter, Andy; Pardo, Salvatore; McGinn, Thomas

    2016-02-01

    Electronic health record (EHR)-based clinical decision support (CDS) tools are rolled out with the urgency to meet federal requirements without time for usability testing and refinement of the user interface. As part of a larger project to design, develop and integrate a pulmonary embolism CDS tool for emergency physicians, we conducted a formative assessment to determine providers' level of interest and input on designs and content. This was a study to conduct a formative assessment of emergency medicine (EM) physicians that included focus groups and key informant interviews. The focus of this study was twofold, to determine the general attitude towards CDS tool integration and the ideal integration point into the clinical workflow. To accomplish this, we first approached EM physicians in a focus group, then, during key informant interviews, we presented workflow designs and gave a scenario to help the providers visualise how the CDS tool works. Participants were asked questions regarding the trigger location, trigger words, integration into their workflow, perceived utility and heuristic of the tool. Results from the participants' survey responses to trigger location, perceived utility and efficiency, indicated that the providers felt the tool would be more of a hindrance than an aid. However, some providers commented that they had not had exposure to CDS tools but had used online calculators, and thought the tools would be helpful at the point-of-care if integrated into the EHR. Furthermore, there was a preference for an order entry wireframe. This study highlights several factors to consider when designing CDS tools: (1) formative assessment of EHR functionality and clinical environment workflow, (2) focus groups and key informative interviews to incorporate providers' perceptions of CDS and workflow integration and/or (3) the demonstration of proposed workflows through wireframes to help providers visualise design concepts.

  12. Synergistic evaluation of a complex conglomerate reservoir for EOR, Barrancas formation, Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Simlote, V.N.; Ebanks, W.J.; Eslinger, E.V.; Harpole, K.J.

    1985-02-01

    An engineering/geological study of the Top Red Conglomerate (TRC) section of the Barrancas formation, Mendoza area, Argentina, was conducted (1) to evaluate historical waterflood performance and recovery efficiency and (2) to develop a reservoir description and predictive model for later use in evaluation of reservoir response to EOR process applications. Original oil in place (OOIP) in the TRC reservoir was about 400 million STB (63.6 x 10/sup 6/ stock-tank m/sup 3/). The field had produced about 154 million STB (24.5 x 10/sup 6/ stock-tank m/sup 3/) or 38.5% OOIP through 1980 and is under consideration for application of a caustic flooding EOR process. The TRC shows extremely large variations in permeability, both areally and vertically, owing to its origin as the uppermost part of a thick, alluvial fan, braided channel sequence of sediments. Porosity and permeability development in these rocks is governed primarily by the abundance of detrital clays. Reservoir quality also is reduced somewhat in localized areas by the presence of calcite and zeolite cements and by authigenic clays. An abundance of chemically reactive minerals in the formation poses a significant potential for formation damage and/or adverse reactions with injected EOR chemicals. A geological description of layering and areal variability in the reservoir was developed and used to guide the application of a black oil simulator to two cross-sectional models. Simulation of waterflood performance indicated good vertical sweep efficiency near injection wells, with less efficient sweep farther away owing to gravity segregation and an adverse mobility ratio. A preliminary screening and feasibility study evaluated several EOR processes for recovering the oil left after waterflooding. Caustic flooding appeared to be the most feasible EOR process for application in this reservoir.

  13. CO2 Photoreduction by Formate Dehydrogenase and a Ru-Complex in a Nanoporous Glass Reactor.

    Science.gov (United States)

    Noji, Tomoyasu; Jin, Tetsuro; Nango, Mamoru; Kamiya, Nobuo; Amao, Yutaka

    2017-02-01

    In this study, we demonstrated the conversion of CO2 to formic acid under ambient conditions in a photoreduction nanoporous reactor using a photosensitizer, methyl viologen (MV(2+)), and formate dehydrogenase (FDH). The overall efficiency of this reactor was 14 times higher than that of the equivalent solution. The accumulation rate of formic acid in the nanopores of 50 nm is 83 times faster than that in the equivalent solution. Thus, this CO2 photoreduction nanoporous glass reactor will be useful as an artificial photosynthesis system that converts CO2 to fuel.

  14. A Highly Efficient Heterogenized Iridium Complex for the Catalytic Hydrogenation of Carbon Dioxide to Formate.

    Science.gov (United States)

    Park, Kwangho; Gunasekar, Gunniya Hariyanandam; Prakash, Natarajan; Jung, Kwang-Deog; Yoon, Sungho

    2015-10-26

    A heterogenized catalyst on a highly porous covalent triazine framework was synthesized and characterized to have a coordination environment similar to that of its homogeneous counterpart. The catalyst efficiently converted CO2 into formate through hydrogenation with a turnover number of 5000 after 2 h and an initial turnover frequency of up to 5300 h(-1) ; both of these values are the highest reported to date for a heterogeneous catalyst, which makes it attractive toward industrial application. Furthermore, the synthesized catalyst was found to be stable in air and was recycled by simple filtration without significant loss of catalytic activity.

  15. A role for protein phosphatase PP1γ in SMN complex formation and subnuclear localization to Cajal bodies.

    Science.gov (United States)

    Renvoisé, Benoît; Quérol, Gwendoline; Verrier, Eloi Rémi; Burlet, Philippe; Lefebvre, Suzie

    2012-06-15

    The spinal muscular atrophy (SMA) gene product SMN forms with gem-associated protein 2-8 (Gemin2-8) and unrip (also known as STRAP) the ubiquitous survival motor neuron (SMN) complex, which is required for the assembly of spliceosomal small nuclear ribonucleoproteins (snRNPs), their nuclear import and their localization to subnuclear domain Cajal bodies (CBs). The concentration of the SMN complex and snRNPs in CBs is reduced upon SMN deficiency in SMA cells. Subcellular localization of the SMN complex is regulated in a phosphorylation-dependent manner and the precise mechanisms remain poorly understood. Using co-immunoprecipitation in HeLa cell extracts and in vitro protein binding assays, we show here that the SMN complex and its component Gemin8 interact directly with protein phosphatase PP1γ. Overexpression of Gemin8 in cells increases the number of CBs and results in targeting of PP1γ to CBs. Moreover, depletion of PP1γ by RNA interference enhances the localization of the SMN complex and snRNPs to CBs. Consequently, the interaction between SMN and Gemin8 increases in cytoplasmic and nuclear extracts of PP1γ-depleted cells. Two-dimensional protein gel electrophoresis revealed that SMN is hyperphosphorylated in nuclear extracts of PP1γ-depleted cells and expression of PP1γ restores these isoforms. Notably, SMN deficiency in SMA leads to the aberrant subcellular localization of Gemin8 and PP1γ in the atrophic skeletal muscles, suggesting that the function of PP1γ is likely to be affected in disease. Our findings reveal a role of PP1γ in the formation of the SMN complex and the maintenance of CB integrity. Finally, we propose Gemin8 interaction with PP1γ as a target for therapeutic intervention in SMA.

  16. The Catabolite Repressor Protein-Cyclic AMP Complex Regulates csgD and Biofilm Formation in Uropathogenic Escherichia coli.

    Science.gov (United States)

    Hufnagel, David A; Evans, Margery L; Greene, Sarah E; Pinkner, Jerome S; Hultgren, Scott J; Chapman, Matthew R

    2016-12-15

    The extracellular matrix protects Escherichia coli from immune cells, oxidative stress, predation, and other environmental stresses. Production of the E. coli extracellular matrix is regulated by transcription factors that are tuned to environmental conditions. The biofilm master regulator protein CsgD upregulates curli and cellulose, the two major polymers in the extracellular matrix of uropathogenic E. coli (UPEC) biofilms. We found that cyclic AMP (cAMP) regulates curli, cellulose, and UPEC biofilms through csgD The alarmone cAMP is produced by adenylate cyclase (CyaA), and deletion of cyaA resulted in reduced extracellular matrix production and biofilm formation. The catabolite repressor protein (CRP) positively regulated csgD transcription, leading to curli and cellulose production in the UPEC isolate, UTI89. Glucose, a known inhibitor of CyaA activity, blocked extracellular matrix formation when added to the growth medium. The mutant strains ΔcyaA and Δcrp did not produce rugose biofilms, pellicles, curli, cellulose, or CsgD. Three putative CRP binding sites were identified within the csgD-csgB intergenic region, and purified CRP could gel shift the csgD-csgB intergenic region. Additionally, we found that CRP binded upstream of kpsMT, which encodes machinery for K1 capsule production. Together our work shows that cAMP and CRP influence E. coli biofilms through transcriptional regulation of csgD IMPORTANCE The catabolite repressor protein (CRP)-cyclic AMP (cAMP) complex influences the transcription of ∼7% of genes on the Escherichia coli chromosome (D. Zheng, C. Constantinidou, J. L. Hobman, and S. D. Minchin, Nucleic Acids Res 32:5874-5893, 2004, https://dx.doi.org/10.1093/nar/gkh908). Glucose inhibits E. coli biofilm formation, and ΔcyaA and Δcrp mutants show impaired biofilm formation (D. W. Jackson, J.W. Simecka, and T. Romeo, J Bacteriol 184:3406-3410, 2002, https://dx.doi.org/10.1128/JB.184.12.3406-3410.2002). We determined that the c

  17. WRAP53 is essential for Cajal body formation and for targeting the survival of motor neuron complex to Cajal bodies.

    Science.gov (United States)

    Mahmoudi, Salah; Henriksson, Sofia; Weibrecht, Irene; Smith, Stephen; Söderberg, Ola; Strömblad, Staffan; Wiman, Klas G; Farnebo, Marianne

    2010-11-02

    The WRAP53 gene gives rise to a p53 antisense transcript that regulates p53. This gene also encodes a protein that directs small Cajal body-specific RNAs to Cajal bodies. Cajal bodies are nuclear organelles involved in diverse functions such as processing ribonucleoproteins important for splicing. Here we identify the WRAP53 protein as an essential factor for Cajal body maintenance and for directing the survival of motor neuron (SMN) complex to Cajal bodies. By RNA interference and immunofluorescence we show that Cajal bodies collapse without WRAP53 and that new Cajal bodies cannot be formed. By immunoprecipitation we find that WRAP53 associates with the Cajal body marker coilin, the splicing regulatory protein SMN, and the nuclear import receptor importinβ, and that WRAP53 is essential for complex formation between SMN-coilin and SMN-importinβ. Furthermore, depletion of WRAP53 leads to accumulation of SMN in the cytoplasm and prevents the SMN complex from reaching Cajal bodies. Thus, WRAP53 mediates the interaction between SMN and associated proteins, which is important for nuclear targeting of SMN and the subsequent localization of the SMN complex to Cajal bodies. Moreover, we detect reduced WRAP53-SMN binding in patients with spinal muscular atrophy, which is the leading genetic cause of infant mortality worldwide, caused by mutations in SMN1. This suggests that loss of WRAP53-mediated SMN trafficking contributes to spinal muscular atrophy.

  18. WRAP53 is essential for Cajal body formation and for targeting the survival of motor neuron complex to Cajal bodies.

    Directory of Open Access Journals (Sweden)

    Salah Mahmoudi

    Full Text Available The WRAP53 gene gives rise to a p53 antisense transcript that regulates p53. This gene also encodes a protein that directs small Cajal body-specific RNAs to Cajal bodies. Cajal bodies are nuclear organelles involved in diverse functions such as processing ribonucleoproteins important for splicing. Here we identify the WRAP53 protein as an essential factor for Cajal body maintenance and for directing the survival of motor neuron (SMN complex to Cajal bodies. By RNA interference and immunofluorescence we show that Cajal bodies collapse without WRAP53 and that new Cajal bodies cannot be formed. By immunoprecipitation we find that WRAP53 associates with the Cajal body marker coilin, the splicing regulatory protein SMN, and the nuclear import receptor importinβ, and that WRAP53 is essential for complex formation between SMN-coilin and SMN-importinβ. Furthermore, depletion of WRAP53 leads to accumulation of SMN in the cytoplasm and prevents the SMN complex from reaching Cajal bodies. Thus, WRAP53 mediates the interaction between SMN and associated proteins, which is important for nuclear targeting of SMN and the subsequent localization of the SMN complex to Cajal bodies. Moreover, we detect reduced WRAP53-SMN binding in patients with spinal muscular atrophy, which is the leading genetic cause of infant mortality worldwide, caused by mutations in SMN1. This suggests that loss of WRAP53-mediated SMN trafficking contributes to spinal muscular atrophy.

  19. Preparation and Standard Formation Enthalpy of 2-Amino-4,6-dimethylpyrimidine and Its Related Complexes of Copper

    Institute of Scientific and Technical Information of China (English)

    CHEN San-ping; WEI Qing; JIAO Bao-juan; GAO Sheng-li

    2003-01-01

    The complexes of hydrous copper chloride and copper nitrate with 2-amino-4,6-dimethylpyrimidine(ADMP) were prepared via reflux in alcohol. The compositions of the complexes were identified as Cu(ADMP)2Cl2*2H2O(b) and Cu(ADMP)(NO3)2*H2O(c) by chemical and elemental analyses. The complexes were characterized by IR, XPS, 1H NMR and TG-DTG techniques. The constant-volume combustion energies of ADMP and the complexes, ΔcE, were determined by a precise rotating-bomb calorimeter at 298.15 K. They were (-3664.53±1.18), (-4978.47±2.72) and (-1696.70±1.36) Kj/mol, respectively. Their standard enthalpies of combustion, ΔcH0m, and standard enthalpies of formation, ΔfH0m, were calculated to be (-3666.39±1.18), (-4977.23±2.72), (-1691.12±1.36) Kj/mol and (19.09±1.43), (-2041.80±3.29), (-2397.24±1.65) Kj/mol, respectively.

  20. Characterization and reconstitution of the nucleational complex responsible for mineral formation by growth plate cartilage matrix vesicles.

    Science.gov (United States)

    Wu, L N; Genge, B R; Sauer, G R; Wuthier, R E

    1996-01-01

    Previous studies revealed that matrix vesicles (MV) have an acid-labile nucleationally active core (ALNAC) essential for mineral formation; current studies were aimed at characterizing and reconstituting ALNAC. SDS-PAGE and FTIR analyses revealed the presence of lipids, proteins and amorphous calcium phosphate (ACP) in ALNAC. Extraction with chloroform-methanol reduced, but did not destroy MV calcification; treatment with chloroform-methanol-HCl destroyed all activity. This acidic solvent extracted the annexins, (phosphatidylserine (PS)-dependent Ca(2+)-binding proteins), and dissociated PS-Ca(2+)-Pi complexes present in the MV. Attempts to reconstitute ALNAC, centered on the Ca(2+)-PS-Pi complex. Various pure lipids, electrolytes and proteins were combined to form a synthetic nucleationally active complex (SNAC), analyzing the rate of Ca2+ uptake. Inclusion of phosphatidylethanolamine (PE) or sphingomyelin (SM) with PS, or Mg2+ or Zn2+ with Ca2+, strongly inhibited activity; incorporation of annexin V increased SNAC activity. Thus, approaching from either deconstruction or reconstruction, it appears that ALNAC is composed of ACP complexed with PS and the annexins. Other lipids, proteins and electrolytes modulate its activity. These findings also indicate how ALNAC must be formed in vivo.

  1. Coordination equilibria in the complex formation of guanylurea with CuII: Formation and stability of binary CuII-guanylurea and ternary CuII-guanylurea-glycinate complexes

    Indian Academy of Sciences (India)

    Tannistha Roy Barman; G N Mukherjee

    2008-07-01

    Combined pH-metric and spectrophotometric investigations on the complex formation equilibria of CuII with guanylurea (H$_{2}^{1}$NC(=O) 2NH.C(=3NH) 4NH2), hereafter, GuH, in the absence and in the presence of glycine (GlyH), in aqueous solution indicates variety of binary and mixed-ligand complexes: Cu(Gu)+, Cu(Gu)(OH); Cu(Gu)2, Cu(Gu-H)(Gu)-, Cu(Gu-H)$_{2}^{2-}$, Cu(Gu-H)(Gu-2H)3-; Cu(Gly)+, Cu(Gly) (OH); Cu(Gly)(Gu); Cu(Gly)(Gu-H)-, Cu(Gly)(Gu-2H)2-; (Gly)Cu(Gu)Cu(Gly)+, (Gly)Cu(Gu-H)Cu(Gly) and (Gly)Cu(Gu-2H)Cu(Gly)-. At pH < 6, guanylurea anion (Gu-) acts as a [(C=O), 3N-] or [=1NH, 3N-] bidentate ligand and above pH 7 it is transformed through a coordination equilibrium into a (=1N-, =3N-) bidentate ligand, similar to biguanide dianion. Occurrence of dinuclear complex species, (Gly) Cu(Gu)Cu(Gly)+, in the complexation equilibria, indicates bridging double bidentate [(1NH2, 3N-), (C=O, 4NH2)] and/or [(1NH2, 4NH2), (C=O, 3N-)] chelation by Gu- ion in an isomeric equilibrium. Above pH 6.5, the dinuclear complex decomposes mostly to the mononuclear species, Cu(Gly)(OH) and Cu(Gu)(OH) and only partly deprotonates to (Gly)Cu(Gu-H)Cu(Gly) and (Gly)Cu(Gu-2H)Cu(Gly)-. Electronic spectral shifts, with change of pH have been correlated with the possible modes of coordination of guanylurea species.

  2. Mesoscopic Modeling of Thrombus Formation and Growth: Platelet Deposition in Complex Geometries

    Science.gov (United States)

    Yazdani, Alireza; Karniadakis, George

    2014-11-01

    Haemodynamics and blood rheology are important contributing factors to thrombus formation at a vulnerable vessel wall, and adhesion of platelets to a vascular surface, particularly in regions of flow stagnation, recirculation and reattachment is significantly important in formation of thrombi. For example, haemodynamic micro-environment can have effects on thrombosis inside the atherosclerotic plaques and aneurysms. To study these effects, we have developed and validated a model for platelet aggregation in blood flow using Dissipative Particle Dynamics (DPD) method. In this model platelets are considered as single DPD particles interacting with each other via Morse potential once activated. We assign an activation delay time to each platelet such that they remain passive during that time. We investigate the effect of different geometries on platelet aggregation by considering arterial stenosis at different levels of occlusion, and aneurysms of different shapes and sizes. The results show a marked increase in platelet aggregation within the boundaries of deceleration zone by increasing the degree of stenosis. Further, we observe enhanced platelet margination and wall deposition in the presence of red blood cells.

  3. Synergistic evaluation of a complex conglomerate reservoir for enhanced oil recovery, Barrancas Formation, Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Simlote, V.N.; Ebanks, W.J.; Eslinger, E.V.

    1982-09-01

    An Engineering-geological study of the Top Red Conglomerate (TRC) portions of the Barrancas formation, Mendoza area, Argentina, was conducted to evaluate waterflood performance and develop a predictive model for use in evaluating reservoir response to caustic flooding. Initial oil in place of the TRC reservoir was approximately 400 million STB. The field has produced 154 million STB through 1980, and it is being considered for enhanced recovery processes. The TRC has large variations in permeability, owing to its origin as the uppermost part of a thick alluvial fan-braided channel sequence of sediments. Porosity and permeability development in these rocks are governed mainly by the abundance of detrital clay, and are reduced somewhat by calcite and zeolite cements and authigenic clays. Chemically reactive components are potential causes of formation damage by reactions with injected chemicals. A geological model of layering and areal variability in the reservoir was used to guide the application of a black oil simulator to two cross-sections. This simulation of waterflooded performance indicated good vertical sweep efficiency near injection wells but less efficient sweep farther away because of gravity segregation. The relative merits of several enhanced recovery processes were evaluated for recovering the oil left after waterflooding. Caustic flooding appears to be the most feasible; therefore, the chemical reactivity of representative core samples were evaluated. The mineralogy and cation exchange capacity (CEC) results are presented. CEC values were compared with short term caustic consumption measurements.

  4. Formation and structure of the first metal complexes comprising amidino-guanidinate ligands.

    Science.gov (United States)

    Sroor, Farid M; Liebing, Phil; Hrib, Cristian G; Gräsing, Daniel; Hilfert, Liane; Edelmann, Frank T

    2016-11-01

    The first metal complexes comprising amidino-guanidinate ligands have been prepared and structurally characterized, namely bis-[μ-N,N',N'',N'''-tetraisopropyl-1-(1-butyl-amidinato)guanidinato-κ(3)N(1),N(2):N(2)]bis-[(tetra-hydro-furan)lithium], [Li2(C18H37N4)2(C4H8O)2], (2), and [bis-(tetra-hydro-furan)-lithium]-di-μ-chlorido-{(N,N'-di-cyclo-hexyl-1-butyl-amidinato-κ(2)N(1),N(2))[N,N',N'',N'''-tetra-cyclo-hexyl-1-(1-butyl-amidinato)guanidinato-κ(2)N(1),N(2)]holmate(III)}, [HoLiCl2(C4H8O)2(C17H31N2)(C30H53N4)], (3). The novel lithium amidino-guanidinate precursors Li[ (n) BuC(=NR)(NR)C(NR)2] [1: R = Cy (cyclo-hex-yl), 2: R = (i) Pr) were obtained by treatment of N,N'-diorganocarbodi-imides, R-N=C=N-R (R = (i) Pr, Cy), with 0.5 equivalents of n-butyl-lithium under well-defined reaction conditions. An X-ray diffraction study of 2 revealed a ladder-type dimeric structure in the solid state. Reaction of anhydrous holmium(III) chloride with in situ-prepared 2 afforded the unexpected holmium 'ate' complex [ (n) BuC(=NCy)(NCy)C(NCy)2]Ho[ (n) BuC(NCy)2](μ-Cl)2Li(THF)2 (3) in 71% yield. An X-ray crystal structure determination of 3 showed that this complex contains both an amidinate ligand and the new amidino-guanidinate ligand.

  5. Formation and structure of the first metal complexes comprising amidinoguanidinate ligands

    Directory of Open Access Journals (Sweden)

    Farid M. Sroor

    2016-11-01

    Full Text Available The first metal complexes comprising amidinoguanidinate ligands have been prepared and structurally characterized, namely bis[μ-N,N′,N′′,N′′′-tetraisopropyl-1-(1-butylamidinatoguanidinato-κ3N1,N2:N2]bis[(tetrahydrofuranlithium], [Li2(C18H37N42(C4H8O2], (2, and [bis(tetrahydrofuranlithium]-di-μ-chlorido-{(N,N′-dicyclohexyl-1-butylamidinato-κ2N1,N2[N,N′,N′′,N′′′-tetracyclohexyl-1-(1-butylamidinatoguanidinato-κ2N1,N2]holmate(III}, [HoLiCl2(C4H8O2(C17H31N2(C30H53N4], (3. The novel lithium amidinoguanidinate precursors Li[nBuC(=NR(NRC(NR2] [1: R = Cy (cyclohexyl, 2: R = iPr were obtained by treatment of N,N′-diorganocarbodiimides, R—N=C=N—R (R = iPr, Cy, with 0.5 equivalents of n-butyllithium under well-defined reaction conditions. An X-ray diffraction study of 2 revealed a ladder-type dimeric structure in the solid state. Reaction of anhydrous holmium(III chloride with in situ-prepared 2 afforded the unexpected holmium `ate' complex [nBuC(=NCy(NCyC(NCy2]Ho[nBuC(NCy2](μ-Cl2Li(THF2 (3 in 71% yield. An X-ray crystal structure determination of 3 showed that this complex contains both an amidinate ligand and the new amidinoguanidinate ligand.

  6. Formation and structure of the first metal complexes comprising amidino­guanidinate ligands

    Science.gov (United States)

    Sroor, Farid M.; Liebing, Phil; Hrib, Cristian G.; Gräsing, Daniel; Hilfert, Liane; Edelmann, Frank T.

    2016-01-01

    The first metal complexes comprising amidino­guanidinate ligands have been prepared and structurally characterized, namely bis­[μ-N,N′,N′′,N′′′-tetraisopropyl-1-(1-butyl­amidinato)guanidinato-κ3 N 1,N 2:N 2]bis­[(tetra­hydro­furan)lithium], [Li2(C18H37N4)2(C4H8O)2], (2), and [bis­(tetra­hydro­furan)­lithium]-di-μ-chlorido-{(N,N′-di­cyclo­hexyl-1-butyl­amidinato-κ2 N 1,N 2)[N,N′,N′′,N′′′-tetra­cyclo­hexyl-1-(1-butyl­amidinato)guanidinato-κ2 N 1,N 2]holmate(III)}, [HoLiCl2(C4H8O)2(C17H31N2)(C30H53N4)], (3). The novel lithium amidino­guanidinate precursors Li[nBuC(=NR)(NR)C(NR)2] [1: R = Cy (cyclo­hex­yl), 2: R = iPr) were obtained by treatment of N,N′-diorganocarbodi­imides, R—N=C=N—R (R = iPr, Cy), with 0.5 equivalents of n-butyl­lithium under well-defined reaction conditions. An X-ray diffraction study of 2 revealed a ladder-type dimeric structure in the solid state. Reaction of anhydrous holmium(III) chloride with in situ-prepared 2 afforded the unexpected holmium ‘ate’ complex [nBuC(=NCy)(NCy)C(NCy)2]Ho[nBuC(NCy)2](μ-Cl)2Li(THF)2 (3) in 71% yield. An X-ray crystal structure determination of 3 showed that this complex contains both an amidinate ligand and the new amidino­guanidinate ligand. PMID:27840700

  7. An analysis of packaging formats for complex digtal objects: review of principles

    Science.gov (United States)

    Bekaert, Jeroen L.; Hochstenbach, Patrick; De Kooning, Emiel; Van de Walle, Rik

    2003-11-01

    During recent years, the number of organizations making digital information available has massively increased. This evolution encouraged the development of standards for packaging and encoding digital representations of complex objects (such as a digital music albums or digitized books and photograph albums). The primary goal of this article is to offer a method to compare these packaging standards and best practices tailored to the needs of the digital library community and the rising digital preservation programs. The contribution of this paper is the definition of an integrated reference model, based on both the OAIS framework and some additional significant properties that affect the quality, usability, encoding and behavior of the digital objects.

  8. Melatonin Stimulates Dendrite Formation and Complexity in the Hilar Zone of the Rat Hippocampus: Participation of the Ca++/Calmodulin Complex

    Directory of Open Access Journals (Sweden)

    Aline Domínguez-Alonso

    2015-01-01

    Full Text Available Melatonin (MEL, the main product synthesized by the pineal gland, stimulates early and late stages of neurodevelopment in the adult brain. MEL increases dendrite length, thickness and complexity in the hilar and mossy neurons of hippocampus. Dendrite formation involves activation of Ca2+/Calmodulin (CaM-dependent kinase II (CaMKII by CaM. Previous work showed that MEL increased the synthesis and translocation of CaM, suggesting that MEL activates CaM-dependent enzymes by this pathway. In this work we investigated whether MEL stimulates dendrite formation by CaMKII activation in organotypic cultures from adult rat hippocampus. We found that the CaMKII inhibitor, KN-62, abolished the MEL stimulatory effects on dendritogenesis and that MEL increased the relative amount of CaM in the soluble fraction of hippocampal slices. Also, PKC inhibition abolished dendritogenesis, while luzindole, an antagonist of MEL receptors (MT1/2, partially blocked the effects of MEL. Moreover, autophosphorylation of CaMKII and PKC was increased in presence of MEL, as well as phosphorylation of ERK1/2. Our results indicate that MEL stimulates dendrite formation through CaMKII and the translocation of CaM to the soluble fraction. Dendritogenesis elicited by MEL also required PKC activation, and signaling through MT1/2 receptors was partially involved. Data strongly suggest that MEL could repair the loss of hippocampal dendrites that occur in neuropsychiatric disorders by increasing CaM levels and activation of CaMKII.

  9. Loss of Snf5 Induces Formation of an Aberrant SWI/SNF Complex

    Directory of Open Access Journals (Sweden)

    Payel Sen

    2017-02-01

    Full Text Available The SWI/SNF chromatin remodeling complex is highly conserved from yeast to human, and aberrant SWI/SNF complexes contribute to human disease. The Snf5/SMARCB1/INI1 subunit of SWI/SNF is a tumor suppressor frequently lost in pediatric rhabdoid cancers. We examined the effects of Snf5 loss on the composition, nucleosome binding, recruitment, and remodeling activities of yeast SWI/SNF. The Snf5 subunit is shown by crosslinking-mass spectrometry (CX-MS and subunit deletion analysis to interact with the ATPase domain of Snf2 and to form a submodule consisting of Snf5, Swp82, and Taf14. Snf5 promotes binding of the Snf2 ATPase domain to nucleosomal DNA and enhances the catalytic and nucleosome remodeling activities of SWI/SNF. Snf5 is also required for SWI/SNF recruitment by acidic transcription factors. RNA-seq analysis suggests that both the recruitment and remodeling functions of Snf5 are required in vivo for SWI/SNF regulation of gene expression. Thus, loss of SNF5 alters the structure and function of SWI/SNF.

  10. The invariant chain p35 isoform promotes formation of nonameric complexes with MHC II molecules.

    Science.gov (United States)

    Cloutier, Maryse; Gauthier, Catherine; Fortin, Jean-Simon; Thibodeau, Jacques

    2014-07-01

    Four different isoforms of the human invariant chain (Ii) have been described (p33, p35, p41 and p43). These heterotrimerize in the endoplasmic reticulum (ER) before associating with MHC class II molecules (MHCIIs). However, the final stoichiometry of the Ii/MHCII complex remains debated. This is particularly interesting as both p35 and p43 include a di-arginine motif that requires masking by MHCII to allow ER egress. Here, to functionally address the requirement for stoichiometric interactions, we used a recombinant DR heterodimer bearing its own cytoplasmic di-lysine ER-retention motif (DRKKAA). When coexpressed with p33 and a control myc-tagged DR (DRmyc), DRKKAA was retained in the ER but had little impact on surface expression of DRmyc. However, when coexpressed with p35, DRKKAA restricted the surface expression of DRmyc, indicating that Ii trimers can be loaded with more than one MHCII. Similar results were obtained using HLA-DQ instead of DRmyc, showing that a single trimeric Ii scaffold can include distinct MHCII isotypes. Altogether, these results demonstrate that the subunit stoichiometry of oligomeric Ii/MHCII complexes is influenced by p35.

  11. Separation of drug stereoisomers by the formation of. beta. -cyclodextrin inclusion complexes

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, D.W.; Ward, T.J.; Armstrong, R.D.; Beesley, T.E.

    1986-05-30

    For many drugs, only racemic mixtures are available for clinical use. Because different stereoisomers of drugs often cause different physiological responses, the use of pure isomers could elicit more exact therapeutic effects. Differential complexation of a variety of drug stereoisomers by immobilized ..beta..-cyclodextrin was investigated. Chiral recognition and racemic resolution were observed with a number of compounds from such clinically useful classes as ..beta..-blockers, calcium-channel blockers, sedative hypnotics, antihistamines, anticonvulsants, diuretics, and synthetic opiates. Separation of the diastereomers of the cardioactive and antimalarial cinchona alkaloids and of two antiestrogens was demonstrated as well. Three dimensional projections of ..beta..-cyclodextrin complexes of propanol, which is resolved by this technique, and warfarin, which is not, are compared. These studies have improved the understanding and application of the chiral interactions of ..beta..-cyclodextrin, and they have demonstrated a means to measure optical purity and to isolate or produce pure enantiomers of drugs. In addition, this highly specific technique could also be used in the pharmacological evaluation of enantiometric drugs. 27 references, 3 figures, 2 tables.

  12. Surfactant induced complex formation and their effects on the interfacial properties of seawater.

    Science.gov (United States)

    Guzmán, Eduardo; Santini, Eva; Benedetti, Alessandro; Ravera, Francesca; Ferrari, Michele; Liggieri, Libero

    2014-11-01

    The effect of a cationic surfactant, hexadecyltrimethylammonium bromide (CTAB), on the interfacial properties of seawater has been studied by dynamic and equilibrium surface tension and by dilational rheology essays. Important modifications of the surface tension and dilational rheology response have been observed already at the very low CTAB concentrations, where the effects due to the high ionic strength are negligible. The comparison with the effects of CTAB in different seawater models, or in natural seawater fractions, points out the establishment of strong interactions between the surfactant molecules and the lipophilic fraction of organic material dispersed/dissolved in seawater, affecting the interfacial activity of the molecules. Considering the biochemical richness of seawater, these results can be explained assuming interaction mechanisms and adsorption schemes similar to those speculated for protein and other macromolecules in the presence of surfactants, which in fact show similar features. Thus already at the low concentrations the surfactant molecules form highly surface-active complexes with part of the organic fraction of seawater. At the larger surfactant concentrations these complexes compete for adsorption with an excess of free CTAB molecules which, according to the thermodynamic conditions, are most favoured to occupy the liquid interface. The results of this study underline the important role of the sea organic content in enhancing the surface-activity of surfactants, which is relevant for a deeper understand of the direct and indirect effects of these types of pollutants on the physico-chemical environment in the sea coastal areas and develop mitigation strategies.

  13. Modified photoreactivity due to mixed crystal formation. I. Three mixed crystals between isostructural cobaloxime complexes.

    Science.gov (United States)

    Vithana, Champika; Uekusa, Hidehiro; Sekine, Akiko; Ohashi, Yuji

    2002-04-01

    Three crystals of 2-cyanoethyl cobaloxime complexes with 3-chloropyridine, 3-bromopyridine and 3-methylpyridine as axial base ligands are isostructural to one another. Three mixed crystals were formed between the pairs: (3-bromopyridine)(2-cyanoethyl)cobaloxime-(2-cyanoethyl)(3-methylpyridine)cobaloxime(0.45/0.55);(3-chloropyridine)(2-cyanoethyl)cobaloxime-(2-cyanoethyl)(3bromopyridine)cobaloxime (0.61/0.39); (3-chloropyridine)(2-cyanoethyl)cobaloxime-(2-cyanoethyl)(3-methylpyridine)cobaloxime (0.44/0.56). The X-ray crystal structure analysis revealed that the mixed compounds are also isostructural to the component crystals. It was found from the change in IR spectra that the 2-cyanoethyl groups in the three mixed crystals isomerized to 1-cyanoethyl groups on exposure to a xenon lamp, as observed for the 2-cyanoethyl groups in the component crystals. Rate constants for the three mixed and three component crystals, measured under the same conditions, are approximately the same, as the reaction cavities for the 2-cyanoethyl groups in the six crystals have almost the same size. For the mixed crystal between 3-chloropyridine and 3-methylpyridine complexes, the isomerization proceeded with retention of the single-crystal form. The conformation and configuration of the 1-cyanoethyl group that was produced were well explained by the shape of the reaction cavity before irradiation.

  14. Tribofilm Formation As a Result of Complex Interaction at the Tool/Chip Interface during Cutting

    Directory of Open Access Journals (Sweden)

    German S. Fox-Rabinovich

    2014-07-01

    Full Text Available Tribofilms are dynamic structures that form at the interface during frictional sliding. These films play a significant role in friction control, particularly under heavy loaded/high temperature conditions, such as those found at the cutting tool/chip interface. The thermodynamic aspects of tribofilm formation are discussed here. Thermodynamic analysis of entropy production during friction shows that there are two types of tribofilms that affect the wear behavior of a cutting tool: (1 tribofilms forming as a result of the surface modification of the cutting tools with further tribo-oxidation; and (2 tribofilms that form as a result of material transfer from the contacting frictional body (the workpiece during the tool/chip interaction. Experimental examples are presented, outlining the beneficial role of both types of tribofilms.

  15. Formation of high nuclearity mixed-valent polyoxovanadates in the presence of copper amine complexes

    Indian Academy of Sciences (India)

    Jency Thomas; Sanjeev Sharma; S E Lofland; K V Ramanujachary; A Ramanana

    2006-01-01

    Two new Müller-type clusters, a one-dimensional solid {Cu()2}4[Cl ⊂ V15O36]$\\cdot$12H2O 1, and a three-dimensional solid {Cu()2}4[Cl ⊂ V18O42]$\\cdot$12H2O 2, have been synthesised by employing identical hydrothermal conditions except varying the nature of organic diamine. 1 crystallised in a chiral space group 212121 with = 12.757(1), = 18.927(2) and = 28.590(3) Å, and = 4. 2 crystallised in a tetragonal system with space group 4/, = 15.113(1) and = 18.542(3) Å, and = 2. Mixed-valent vanadium ions in structures 1 and 2 have been established both by magnetisation and bond-length bondvalence measurements. Chemistry of formation of high nuclearity polyoxovanadate clusters is discussed.

  16. Formation of complex Al-N-C layer in aluminium by successive carbon and nitrogen implantation

    Energy Technology Data Exchange (ETDEWEB)

    Uglov, V.V.; Cherenda, N.N. E-mail: info@research.bsu.unibel.by; Khodasevich, V.V.; Sokol, V.A.; Abramov, I.I.; Danilyuk, A.L.; Wenzel, A.; Gerlach, J.; Rauschenbach, B

    1999-01-01

    The results of Auger electron spectroscopy and transmission electron microscopy of the surface layer of aluminium after successive implantation by carbon and nitrogen ions are presented in this work. The energy of implanted ions is 40 keV. The implantation dose varies in the range (3.3-6.5)x10{sup 17} ions/cm{sup 2}. The findings show that successive implantation leads to the formation of two main layers in aluminium. The first layer is AlNC{sub x} (0

  17. Formation of complex Al-N-C layer in aluminium by successive carbon and nitrogen implantation

    Science.gov (United States)

    Uglov, V. V.; Cherenda, N. N.; Khodasevich, V. V.; Sokol, V. A.; Abramov, I. I.; Danilyuk, A. L.; Wenzel, A.; Gerlach, J.; Rauschenbach, B.

    1999-01-01

    The results of Auger electron spectroscopy and transmission electron microscopy of the surface layer of aluminium after successive implantation by carbon and nitrogen ions are presented in this work. The energy of implanted ions is 40 keV. The implantation dose varies in the range (3.3-6.5) × 10 17 ions/cm 2. The findings show that successive implantation leads to the formation of two main layers in aluminium. The first layer is AlNC x (0 < x < 0.5) layer with violated hcp. AlN structure, where carbon atoms form bonds with nitrogen atoms. The second layer contains disoriented Al 4C 3 precipitates and carbon atoms migrated from the first layer. The mechanism of migration is discussed.

  18. On the complexity and dynamics of in vivo Cisplatin-DNA adduct formation using HPLC/ICP-MS.

    Science.gov (United States)

    Ziehe, Matthias; Esteban-Fernández, Diego; Hochkirch, Ulrike; Thomale, Jürgen; Linscheid, Michael W

    2012-10-01

    In this work we present a methodology to measure the complex adduct spectrum caused by the interaction of Cisplatin with DNA. By using an optimized DNA digestion procedure we were able to show that the adduct spectrum in in vivo duplex DNA is much more complex than described so far. For the first time a high abundance of interstrand adducts has been detected by using HPLC/ESI-MS. These adducts could play a key role in the DNA repair mechanisms and the development of cellular resistance to Cisplatin. By species-unspecific isotope dilution analysis HPLC/ICP-MS measurements, we were able to study the kinetics of adduct formation. With these experiments we proved that after the initial formation of adducts a rearrangement occurs on the DNA-strands leading to significant changes in adduct patterns over time. Furthermore, the parameters of the species-unspecific isotope dilution analysis were optimized to allow measurements of specific adducts in the DNA of Cisplatin exposed cells.

  19. In vitro platelet activation, aggregation and platelet-granulocyte complex formation induced by surface modified single-walled carbon nanotubes.

    Science.gov (United States)

    Fent, János; Bihari, Péter; Vippola, Minnamari; Sarlin, Essi; Lakatos, Susan

    2015-08-01

    Surface modification of single-walled carbon nanotubes (SWCNTs) such as carboxylation, amidation, hydroxylation and pegylation is used to reduce the nanotube toxicity and render them more suitable for biomedical applications than their pristine counterparts. Toxicity can be manifested in platelet activation as it has been shown for SWCNTs. However, the effect of various surface modifications on the platelet activating potential of SWCNTs has not been tested yet. In vitro platelet activation (CD62P) as well as the platelet-granulocyte complex formation (CD15/CD41 double positivity) in human whole blood were measured by flow cytometry in the presence of 0.1mg/ml of pristine or various surface modified SWCNTs. The effect of various SWCNTs was tested by whole blood impedance aggregometry, too. All tested SWCNTs but the hydroxylated ones activate platelets and promote platelet-granulocyte complex formation in vitro. Carboxylated, pegylated and pristine SWCNTs induce whole blood aggregation as well. Although pegylation is preferred from biomedical point of view, among the samples tested by us pegylated SWCNTs induced far the most prominent activation and a well detectable aggregation of platelets in whole blood.

  20. Mechanisms of defect complex formation and environmental-assisted fracture behavior of iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, B.R.; Muratov, L.S.; Kang, B.S.J.; Li, K.Z. [West Virginia Univ., Morgantown, WV (United States)

    1997-12-01

    Iron aluminide has excellent corrosion resistance in high-temperature oxidizing-sulfidizing environments; however, there are problems at room and medium temperature with hydrogen embrittlement as related to exposure to moisture. In this research, a coordinated computational modeling/experimental study of mechanisms related to environmental-assisted fracture behavior of selected iron aluminides is being undertaken. The modeling and the experimental work will connect at the level of coordinated understanding of the mechanisms for hydrogen penetration and for loss of strength and susceptibility to fracture. The focus of the modeling component at this point is on the challenging question of accurately predicting the iron vacancy formation energy in Fe{sub 3}A{ell} and the subsequent tendency, if present, for vacancy clustering. The authors have successfully performed, on an ab initio basis, the first calculation of the vacancy formation energy in Fe{sub 3}A{ell}. These calculations include lattice relaxation effects which are quite large. This has significant implications for vacancy clustering effects with consequences to be explored for hydrogen diffusion. The experimental work at this stage has focused on the relationship of the choice and concentration of additives to the improvement of resistance to hydrogen embrittlement and hence to the fracture behavior. For this reason, comparative crack growth tests of FA-186, FA-187, and FA-189 iron aluminides (all with basic composition of Fe-28A{ell}-5Cr, at % with micro-alloying additives of Zr, C or B) under, air, oxygen, or water environment have been performed. These tests showed that the alloys are susceptible to room temperature hydrogen embrittlement in both B2 and DO{sub 3} conditions. Test results indicated that FA-187, and FA-189 are intrinsically more brittle than FA-186.

  1. Formation of the Yandangshan volcanic-plutonic complex (SE China) by melt extraction and crystal accumulation

    Science.gov (United States)

    Yan, Li-Li; He, Zhen-Yu; Jahn, Bor-ming; Zhao, Zhi-Dan

    2016-12-01

    The association of volcanic and shallow plutonic rocks in caldera may provide important clues to the geochemical evolution of silicic magma systems. The Yandangshan caldera is a typical example of late Mesozoic volcanic-plutonic complex in SE China. It is composed of a series of rhyolitic extrusives and subvolcanic intrusions of porphyritic quartz syenites. In this work, we conducted petrological and geochemical studies, as well as zircon dating, on the coexisting volcanic and plutonic rocks from the Yandangshan caldera. The results of SHRIMP and LA-ICP-MS zircon U-Pb dating revealed that the crystallization of the rhyolitic extrusives and subvolcanic intrusions was contemporaneous within analytical errors and in a short period (104-98 Ma). Geochemically, the volcanic rocks are characterized by high Rb/Sr and Rb/Ba ratios and depletion in Ba, Sr, P, Eu and Ti, while the shallow plutons show high K, Ba, Al, Fe and low Rb/Sr and Rb/Ba ratios with insignificant negative Eu anomalies. The volcanic and plutonic rocks have a similar range of zircon Hf isotopic compositions (εHf(t) = - 10.0 to + 1.5) and TDM2 model ages of 2.10-1.23 Ga. They also have comparable whole-rock Sr and Nd isotopic compositions ((87Sr/86Sr)i = 0.7084-0.7090; εNd(t) = - 7.8 to - 6.5) and zircon oxygen isotopic compositions (δ18O mainly = 4.5 to 6.0‰). We argue that the volcanic-plutonic complex of the Yandangshan caldera was formed by reworking of Paleoproterozoic lower crusts in the eastern Cathaysia block, and that the complex could be linked by fractional crystallization and crystal accumulation in a shallow magma chamber. The volcanic rocks represent the highly fractionated end-member, whereas the subvolcanic intrusions of porphyritic quartz syenites could be the residual crystal mushes. This case study could have a general implication for the genetic relationship between volcanic and shallow plutonic rocks in calderas.

  2. The thermodynamic characteristics of complex formation of Cd2+ with N,N-Bis(carboxymethyl)aspartic acid in aqueous solutions at 298.15 K

    Science.gov (United States)

    Lytkin, A. I.; Chernyavskaya, N. V.; Litvinenko, V. E.

    2011-01-01

    The equilibrium constants and heats of formation of complexes of N,N-bis(carboxymethyl)aspartic acid (H4Y) with Cd2+ ions at 298.15 K and ionic strengths of 0.2, 0.5, and 1.0 (KNO3) were determined by potentiometric titration and calorimetrically. The thermodynamic characteristics of formation of the CdY2- complex at fixed and zero ionic strength values were calculated. The values obtained were interpreted.

  3. Combustion energies and standard molar enthalpies of formation for the complexes of the first-row transitional metal chlorides with L-α-histidine

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Seven novel solid complexes of the first-row transitional metal with L-α-histidine were synthesized, and their compositions were determined. The constant-volume combustion energies of the complexes were measured by a precision rotation bomb calorimeter. The standard molar enthalpies of combustion and the standard molar enthalpies of formation were calculated. The results indicated thatthe plots of the standard enthalpies of formation against the atomic number of the metal show a regularity of zigzag.

  4. An Anomalous Formation Pathway for Dislocation-Sulfur Vacancy Complexes in Polycrystalline Monolayer MoS2.

    Science.gov (United States)

    Yu, Zhi Gen; Zhang, Yong-Wei; Yakobson, Boris I

    2015-10-14

    Two-dimensional (2D) molybdenum disulfide (MoS2) has attracted significant attention recently due to its direct bandgap semiconducting characteristics. Experimental studies on monolayer MoS2 show that S vacancy concentration varies greatly; while recent theoretical studies show that the formation energy of S vacancy is high and thus its concentration should be low. We perform density functional theory calculations to study the structures and energetics of vacancy and interstitial in both grain boundary (GB) and grain interior (GI) in monolayer MoS2 and uncover an anomalous formation pathway for dislocation-double S vacancy (V2S) complexes in MoS2. In this pathway, a (5|7) defect in an S-polar GB energetically favorably converts to a (4|6) defect, which possesses a duality: dislocation and double S vacancy. Its dislocation character allows it to glide into GI through thermal activation at high temperatures, bringing the double vacancy with it. Our findings here not only explain why VS is predominant in exfoliated 2D MoS2 and V2S is predominant in chemical vapor deposition (CVD)-grown 2D MoS2 but also reproduce GB patterns in CVD-grown MoS2. The new pathway for sulfur vacancy formation revealed here provides important insights and guidelines for controlling the quality of monolayer MoS2.

  5. Star formation in the filament of S254-S258 OB complex: a cluster in the process of making

    CERN Document Server

    Samal, M R; Jose, J; Zavagno, A; Takahashi, S; Neichel, B; Kim, J S; Chauhan, N; Pandey, A K; Zinchenko, I; Tamura, M; Ghosh, S K

    2015-01-01

    Infrared Dark Clouds are ideal laboratories to study the initial processes of high-mass star and star cluster formation. We investigated star formation activity of an unexplored filamentary dark cloud (~5.7pc x 1.9pc), which itself is part of a large filament (~20pc) located in the S254-S258 OB complex at a distance of 2.5kpc. Using MIPS Spitzer 24 micron data, we uncover 49 sources with SNR greater than 5. We identified 45 sources as candidate YSOs of Class I, Flat-spectrum & Class II nature. Additional 17 candidate YSOs (9 Class I & 8 Class II) are also identified using JHK and WISE photometry. We find that the protostar to Class II sources ratio (~2) and the protostar fraction (~70%) of the region are high. When the protostar fraction compared to other young clusters, it suggests that the star formation in the dark cloud was possibly started only 1 Myr ago. Combining the NIR photometry of the YSO candidates with the theoretical evolutionary models, we infer that most of the candidate YSOs formed in...

  6. A novel high throughput biochemical assay to evaluate the HuR protein-RNA complex formation.

    Directory of Open Access Journals (Sweden)

    Vito G D'Agostino

    Full Text Available The RNA binding protein HuR/ELAVL1 binds to AU-rich elements (AREs promoting the stabilization and translation of a number of mRNAs into the cytoplasm, dictating their fate. We applied the AlphaScreen technology using purified human HuR protein, expressed in a mammalian cell-based system, to characterize in vitro its binding performance towards a ssRNA probe whose sequence corresponds to the are present in TNFα 3' untranslated region. We optimized the method to titrate ligands and analyzed the kinetic in saturation binding and time course experiments, including competition assays. The method revealed to be a successful tool for determination of HuR binding kinetic parameters in the nanomolar range, with calculated Kd of 2.5±0.60 nM, k on of 2.76±0.56*10(6 M(-1 min(-1, and k off of 0.007±0.005 min(-1. We also tested the HuR-RNA complex formation by fluorescent probe-based RNA-EMSA. Moreover, in a 384-well plate format we obtained a Z-factor of 0.84 and an averaged coefficient of variation between controls of 8%, indicating that this biochemical assay fulfills criteria of robustness for a targeted screening approach. After a screening with 2000 small molecules and secondary verification with RNA-EMSA we identified mitoxantrone as an interfering compound with rHuR and TNFα probe complex formation. Notably, this tool has a large versatility and could be applied to other RNA Binding Proteins recognizing different RNA, DNA, or protein species. In addition, it opens new perspectives in the identification of small-molecule modulators of RNA binding proteins activity.

  7. Determination of formation constants and structural characterization of cyclodextrin inclusion complexes with two phenolic isomers: carvacrol and thymol

    Directory of Open Access Journals (Sweden)

    Miriana Kfoury

    2016-01-01

    Full Text Available Carvacrol and thymol have been widely studied for their ability to control food spoilage and to extend shelf-life of food products due to their antimicrobial and antioxidant activities. However, they suffer from poor aqueous solubility and pronounced flavoring ability that limit their application in food systems. These drawbacks could be surpassed by encapsulation in cyclodextrins (CDs. Applications of their inclusion complexes with CDs were reported without investigating the inclusion phenomenon in deep. In this study, inclusion complexes were characterized in terms of formation constants (Kf, complexation efficiency (CE, CD:guest molar ratio and increase in bulk formulation by using an UV–visible competitive method, phase solubility studies as well as 1H and DOSY 1H NMR titration experiments. For the first time, a new algorithmic treatment that combines the chemical shifts and diffusion coefficients variations for all guest protons was applied to calculate Kf. The position of the hydroxy group in carvacrol and thymol did not affect the stoichiometry of the inclusion complexes but led to a different binding stability with CDs. 2D ROESY NMR experiments were also performed to prove the encapsulation and illustrate the stable 3D conformation of the inclusion complexes. The structural investigation was accomplished with molecular modeling studies. Finally, the radical scavenging activity of carvacrol and thymol was evaluated by the ABTS radical scavenging assay. An improvement of this activity was observed upon encapsulation. Taken together, these results evidence that the encapsulation in CDs could be valuable for applications of carvacrol and thymol in food.

  8. On the formation and structure of rare-earth element complexes in aqueous solutions under hydrothermal conditions with new data on gadolinium aqua and chloro complexes

    Science.gov (United States)

    Mayanovic, Robert A.; Anderson, Alan J.; Bassett, William A.; Chou, I.-Ming

    2007-01-01

    (III) chloro complexes increases steadily with temperature from 0.4 ?? 0.2 to 1.7 ?? 0.3 in the 0.006m chloride solution and from 0.9 ?? 0.7 to 1.8 ?? 0.7 in the 0.1m GdCl3 aqueous solution in the 300-500????C range. Conversely, the number of H2O ligands of Gd(H2O)??-nCln+3-n complexes decreases steadily from 8.9 ?? 0.4 to 5.8 ?? 0.7 in the 0.006m GdCl3 aqueous solution and from 9.0 ?? 0.5 to 5.3 ?? 1.0 in the 0.1m GdCl3 aqueous solution at temperatures from 25 to 500????C. Analysis of our results shows that the chloride ions partially displace the inner-shell water molecules during Gd(III) complex formation under hydrothermal conditions. The Gd-OH2 bond of the partially-hydrated Gd(III) chloro complexes exhibits slightly smaller rates of length contraction (??? 0.005??A??/100????C) for both solutions. The structural aspects of chloride speciation of Gd(III) as measured from this study and of Yb(III) as measured from our previous experiments are consistent with the solubility of these and other REE in deep-sea hydrothermal fluids. ?? 2006 Elsevier B.V. All rights reserved.

  9. The role of Glu259 in Escherichia coli elongation factor Tu in ternary complex formation

    DEFF Research Database (Denmark)

    Nautrup Pedersen, Gitte; Rattenborg, Thomas; Knudsen, Charlotte Rohde;

    1998-01-01

    Determination of the crystal structure of the ternary complex formed between elongation factor Tu:GTP and aminoacylated tRNA revealed three regions of interaction between elongation factor Tu and tRNA. The structure indicates that the conserved glutamic acid at position 271 in Thermus aquaticus EF......-Tu could be involved in the binding of the 3' CCA-Phe end of the aminoacylated tRNA. Therefore, the corresponding residue, Glu259, of Escherichia coli EF-Tu was mutated into alanine, aspartic acid, glutamine and tyrosine, in order to substantiate the crystallographic structural evidence and to obtain...... of interaction with tRNA, while mutation to tyrosine abolished completely the interaction with tRNA. Finally, mutation to glutamine resulted in an elongation factor Tu variant behaving like the wild type. In conclusion, the environment around the site binding the CCA-Phe end of the tRNA is very restricted...

  10. Immune complex formation and in situ B-cell clonal expansion in human cerebral cavernous malformations.

    Science.gov (United States)

    Shi, Changbin; Shenkar, Robert; Kinloch, Andrew; Henderson, Scott G; Shaaya, Mark; Chong, Anita S; Clark, Marcus R; Awad, Issam A

    2014-07-15

    Cerebral cavernous malformations (CCMs) represent clusters of dilated vascular channels, predisposing to hemorrhagic stroke and seizures. They are associated with defective blood brain barrier, hemorrhages of different ages and a robust inflammatory cell infiltrate. We report for the first time evidence of co-localized IgG and complement membrane attack complexes in CCM lesions. CD4(+) and CD8(+) T-cells are aggregated with CD20(+) B-cells. And IgG repertoire analyses demonstrate in situ B-cell clonal expansion and antigen-driven affinity maturation in CCMs. These results suggest an organ-intrinsic adaptive immune response in CCMs that should be further characterized as a potential therapeutic target.

  11. The Formation of Complex Organic Compounds in Astrophysical Ices and their Implications for Astrobiology

    Science.gov (United States)

    Sandford, Scott A.

    2015-01-01

    Ices in astrophysical environments are generally dominated by very simple molecules like H2O, CH3OH, CH4, NH3, CO, CO2, etc, although they likely contain PAHs as well. These molecules, particularly H2O, are of direct interest to astrobiology in-and-of themselves since they represent some of the main carriers of the biogenic elements C, H, O, and N. In addition, these compounds are present in the dense interstellar clouds in which new stars and planetary systems are formed and may play a large role in the delivery of volatiles and organics to the surfaces of new planets. However, these molecules are all far simpler than the more complex organic compounds found in living systems.

  12. Formation of palladium nanofilms using electrochemical atomic layer deposition (E-ALD) with chloride complexation.

    Science.gov (United States)

    Sheridan, Leah B; Gebregziabiher, Daniel K; Stickney, John L; Robinson, David B

    2013-02-05

    Pd thin films were formed by electrochemical atomic layer deposition (E-ALD) using surface-limited redox replacement (SLRR) of Cu underpotential deposits (UPD) on polycrystalline Au substrates. An automated electrochemical flow deposition system was used to deposit Pd atomic layers using a sequence of steps referred to as a cycle. The initial step was Cu UPD, followed by its exchange for Pd ions at open circuit, and finishing with a blank rinse to complete the cycle. Deposits were formed with up to 75 cycles and displayed proportional deposit thicknesses. Previous reports by this group indicated excess Pd deposition at the flow cell ingress, from electron probe microanalysis (EPMA). Those results suggested that the SLRR mechanism did not involve direct transfer between a Cu(UPD) atom and a Pd(2+) ion that would take its position. Instead, it was proposed that electrons are transferred through the metallic surface to reduce Pd(2+) ions near the surface where their activity is highest. It was proposed that if the cell was filled completely before a significant fraction of the Cu(UPD) atoms had been oxidized then the deposit would be homogeneous. Previous work with EDTA indicated that the hypothesis had merit, but it proved to be very sensitive to the EDTA concentration. In the present study, chloride was used to complex Pd(2+) ions, forming PdCl(4)(2-), to slow the exchange rate. Both complexing agents led to a decrease in the rate of replacement, producing more homogeneous films. Although the use of EDTA improved the homogeneity, it also decreased the deposit thickness by a factor of 3 compared to the thickness obtained via the use of chloride.

  13. Spectrophotometric determination of nizatidine and ranitidine through charge transfer complex formation.

    Science.gov (United States)

    Walash, M; Sharaf-El Din, M; Metwalli, M E-S; RedaShabana, M

    2004-07-01

    Two Spectrophotometric procedures are presented for the determination of two commonly used H2-receptor antagonists, nizatidine (I) and ranitidine hydrochloride (II). The methods are based mainly on charge transfer complexation reaction of these drugs with either p-chloranilic acid (rho-CA) or 2, 3 dichloro-5, 6-dicyanoquinone (DDQ). The produced colored products are quantified spectrophotometrically at 515 and 467 nm in chloranilic acid and DDQ methods, respectively. The molar ratios for the reaction products and the optimum assay conditions were studied. The methods determine the cited drugs in concentration ranges of 20-200 and 20-160 microg/mL for nizatidine and ranges of 20-240 and 20-140 microg/mL for ranitidine with chloranilic acid and DDQ methods, respectively. A more detailed investigation of the complexes formed was made with respect to their composition, association constant, molar absorptivity and free energy change. The proposed procedures were successfully utilized in the determination of the drugs in pharmaceutical preparations. The standard addition method was applied by adding nizatidine and ranitidine to the previously analyzed tablets or capsules. The recovery of each drug was calculated by comparing the concentration obtained from the spiked mixtures with those of the pure drug. The results of analysis of commercial tablets and the recovery study (standard addition method) of the cited drugs suggested that there is no interference from any excipients, which are present in tablets or capsules. Statistical comparison of the results was performed with regard to accuracy and precision using student's t-test and F-ratio at 95% confidence level. There is no significant difference between the reported and proposed methods with regard to accuracy and precision.

  14. Vipp1 is required for basic thylakoid membrane formation but not for the assembly of thylakoid protein complexes.

    Science.gov (United States)

    Aseeva, Elena; Ossenbühl, Friederich; Sippel, Claudia; Cho, Won K; Stein, Bernhard; Eichacker, Lutz A; Meurer, Jörg; Wanner, Gerhard; Westhoff, Peter; Soll, Jürgen; Vothknecht, Ute C

    2007-02-01

    Vipp1 (vesicle inducing protein in plastids 1) is found in cyanobacteria and chloroplasts where it is essential for thylakoid formation. Arabidopsis thaliana mutant plants with a reduction of Vipp1 to about 20% of wild type content become albinotic at an early stage. We propose that this drastic phenotype results from an inability of the remaining Vipp1 protein to assemble into a homo-oligomeric complex, indicating that oligomerization is a prerequisite for Vipp1 function. A Vipp1-ProteinA fusion protein, expressed in the Deltavipp1 mutant background, is able to reinstate oligomerization and restore photoautotrophic growth. Plants containing Vipp1-ProteinA in amounts comparable to Vipp1 in the wild type exhibit a wild type phenotype. However, plants with a reduced amount of Vipp1-ProteinA protein are growth-retarded and significantly paler than the wild type. This phenotype is caused by a decrease in thylakoid membrane content and a concomitant reduction in photosynthetic activity. To the extent that thylakoid membranes are made in these plants they are properly assembled with protein-pigment complexes and are photosynthetically active. This strongly supports a function of Vipp1 in basic thylakoid membrane formation and not in the functional assembly of thylakoid protein complexes. Intriguingly, electron microscopic analysis shows that chloroplasts in the mutant plants are not equally affected by the Vipp1 shortage. Indeed, a wide range of different stages of thylakoid development ranging from wild-type-like chloroplasts to plastids nearly devoid of thylakoids can be observed in organelles of one and the same cell.

  15. 3-Pyridylmethanol vs. N,N‧-diethylnicotinamide in copper(II) complex formation - A comparative EPR study

    Science.gov (United States)

    Husáriková, L.; Repická, Z.; Valigura, D.; Valko, M.; Mazúr, M.

    2013-10-01

    Copper(II) complexes, formed from 4-chlorosalicylic acid anion A (A = 4-Clsal-), different copper(II) salts (Cu(ac)2 or CuSO4) and different N-donor ligands B (B = 3-pyridylmethanol (ron) or N,N'-diethylnicotinamide (denia)) with varying N-donor ligand-to-metal ratio (x), were studied by EPR spectroscopy in the frozen water/methanol (1:3 v/v) solutions. The number of ligand B molecules coordinated to Cu(II) central ion was determined from the nitrogen perpendicular and parallel superhyperfine splitting multiplets of Cu(II) EPR spectra. It was found for both N-donor ligands: (i) At lower ligand B concentrations (x = 1, 2), [CuB] and/or [CuB2] species having one and/or two molecules of ligands B in equatorial position were dominant. The dominant ternary complex particles were [CuA2B2] species. (ii) At higher ligand B concentrations (x ⩾ 4) the formation of [CuB3] and/or [CuB4] species having three and/or four molecules of ligands B in equatorial position was confirmed. Such information is not possible to get from Cu(II) EPR spectra of powdered samples of given copper(II) complexes.

  16. Fac-mer equilibria of coordinated iminodiacetate (ida2-) in ternary CuII(ida)(H-1B)- complex formation (B = imidazole, benzimidazole) in aqueous solution

    Indian Academy of Sciences (India)

    Susmita Bandyopadhyay; G N Mukherjee

    2003-08-01

    pH potentiometric and spectrophotometric investigations on the complex formation equilibria of CuII with iminodiacetate (ida2-) and heterocyclic N-bases, viz. imidazole and benzimidazole (B), in aqueous solution in binary and ternary systems using different molar ratios of the reactants indicated the formation of complexes of the types, Cu(ida), Cu(ida)(OH)-, (ida)Cu(OH)Cu(ida)-, Cu(B)2+, Cu(H-1B)+, Cu(ida)(H-1B)-, (ida)Cu(B)Cu(ida) and (ida)Cu(H-1B)Cu(ida)-. Formation constants of the complexes at 25 ± 1° at a fixed ionic strength, = 0.1 mol dm-3 (NaNO3) in aqueous solution were evaluated and the complex formation equilibria were elucidated with the aid of speciation curves. Departure of the experimental values of the reproportionation constants (log Cu) of ternary Cu(ida)(H-1B)- complexes from the statistically expected values, despite their formation in appreciable amounts at equilibrium, were assigned to fac(f)-mer(m) equilibria of the ida2- ligand coordinated to CuII, as the N-heterocyclic donors, (H-1B)-, coordinate trans- to the N-(ida2-) atom in the binary Cu(ida) complex to form the ternary Cu(ida) (H-1B)- complexes.

  17. Isotopic evidence for complex microbial ecosystems in the phosphate-rich interval of the Miocene Monterey Formation

    Science.gov (United States)

    Theiling, B. P.; Coleman, M. L.

    2014-12-01

    The middle Miocene Monterey Formation has long been debated as a crucial global sink for organic carbon that led to global cooling. We evaluate proxies for the microbial ecosystem to investigate organic carbon burial within the phosphate-rich interval of the Monterey Formation at Naples Beach, California by combining mineralogical evidence with δ34S analyses of carbonate associated sulfate (CAS). All δ34S are below Miocene seawater values (~22‰, VCDT) and range from +12.2‰ to +18.5‰. δ34SCAS Sulfate reducing bacteria then consume the excess, residual sulfate, generating free H2S in the absence of available iron. H2S diffuses upward towards the sediment-water interface (an oxic-suboxic mixing zone) where H2S is oxidized to 34S-depleted sulfate either aerobically or coupled to nitrate reduction, and lowers seawater pH. The high phosphate content and low carbonate content of this interval of the Monterey Formation supports a model of precipitation in lower pH waters. Assuming a -40‰ fractionation of δ34S due to microbial sulfate reduction, we estimate at least a 10%-20% contribution of sulfate from sulfide oxidation to marine porewater sulfate. These results suggest that the phosphate-rich interval of the Monterey Formation housed a complex suite of iron and sulfate reducing bacteria as well as sulfide oxidizing bacteria, suggesting that significant organic carbon was consumed during early diagenesis and may account for low organic carbon content described in previous studies.

  18. Equilibrium and kinetic analysis of human interleukin-13 and IL-13 receptor alpha-2 complex formation.

    Science.gov (United States)

    Lacy, Eilyn R

    2012-03-01

    Interleukin 13 (IL-13) is a pleiotropic cytokine secreted by activated T cells. Both IL-13 and its polymorphic variant (IL-13-R110Q) have been shown to be associated with multiple diseases such as asthma and allergy. Two IL-13 receptors have been identified, IL-13R alpha-1 receptor (IL-13Rα1) and IL-13R alpha-2 receptor (IL-13Rα2). It has been well established that IL-13 binds to IL-13Rα1 alone with low nM affinity while binding to the IL-13Rα1/IL-4R receptor complex is significantly tighter (pM). The affinity between IL-13 and IL-13Rα2, however, remains elusive. Several values have been reported in the literature varying from 20 pM to 2.5 nM. The affinities previously reported were obtained using surface plasmon resonance (SPR) or Scatchard analysis of (125) I-IL-13 binding data. This report presents the results for the kinetics and equilibrium binding analysis studies performed using label-free kinetic exclusion assay (KEA) for the interaction of human IL-13 and IL-13Rα2. KEA equilibrium analysis showed that the affinities of IL-13Rα2 are 107 and 56 pM for IL-13 and its variant (IL-13-R110Q), respectively. KEA kinetic analysis showed that a tight and very stable complex is formed between IL-13Rα2 and IL-13, as shown by calculated dissociation rate constants slower than 5 × 10(-5) per second. Kinetic analysis also showed significant differences in the kinetic behavior of wild type (wt) versus IL-13-R110Q. IL-13-R110Q not only associates to IL-13Rα2 slower than wt human IL-13 (wt-IL-13), as previously reported, but IL-13-R110Q also dissociates slower than wt-IL-13. These results show that IL-13Rα2 is a high affinity receptor and provide a new perspective on kinetic behavior that could have significant implications in the understanding of the role of IL-13-R110Q in the disease state.

  19. Formation of redispersible polyelectrolyte complex nanoparticles from gallic acid-chitosan conjugate and gum arabic.

    Science.gov (United States)

    Hu, Qiaobin; Wang, Taoran; Zhou, Mingyong; Xue, Jingyi; Luo, Yangchao

    2016-11-01

    Polyelectrolyte complex (PEC) nanoparticles between chitosan (CS) and biomacromolecules offer better physicochemical properties as delivery vehicles for nutrients than other CS-based nanoparticles. Our major objective was to fabricate PEC nanoparticles between water soluble gallic acid-chitosan conjugate (GA-CS) and gum arabic. The optimal fabrication method, physicochemical characteristics and stability were investigated. Furthermore, we also evaluated the effects of nano spray drying technology on the morphology and redispersibility of nanoparticle powders using Buchi B-90 Nano Spray Dryer. Results showed that the mass ratio between GA-CS and gum arabic and the preparation pH had significant contributions in determining the particle size and count rate of the nanoparticles, with the ratio of 3:1 and pH 5.0 being the optimal conditions that resulted in 112.2nm and 122.9kcps. The polyethylene glycol (PEG) played a vital role in forming the well-separated spray dried nanoparticles. The most homogeneous nanoparticles with the smoothest surface were obtained when the mass ratio of GA-CS and PEG was 1:0.5. In addition, the GA-CS/gum arabic spray dried nanoparticles exhibited excellent water-redispersibiliy compared to native CS/gum arabic nanoparticles. Our results demonstrated GA-CS/gum arabic nanoparticles were successfully fabricated with promising physicochemical properties and great potential for their applications in food and pharmaceutical industries.

  20. Soft matter strategies for controlling food texture: formation of hydrogel particles by biopolymer complex coacervation.

    Science.gov (United States)

    Wu, Bi-cheng; Degner, Brian; McClements, David Julian

    2014-11-19

    Soft matter physics principles can be used to address important problems in the food industry. Starch granules are widely used in foods to create desirable textural attributes, but high levels of digestible starch may pose a risk of diabetes. Consequently, there is a need to find healthier replacements for starch granules. The objective of this research was to create hydrogel particles from protein and dietary fiber with similar dimensions and functional attributes as starch granules. Hydrogel particles were formed by mixing gelatin (0.5 wt%) with pectin (0 to 0.2 wt%) at pH values above the isoelectric point of the gelatin (pH 9, 30 °C). When the pH was adjusted to pH 5, the biopolymer mixture spontaneously formed micron-sized particles due to electrostatic attraction of cationic gelatin with anionic pectin through complex coacervation. Differential interference contrast (DIC) microscopy showed that the hydrogel particles were translucent and spheroid, and that their dimensions were determined by pectin concentration. At 0.01 wt% pectin, hydrogel particles with similar dimensions to swollen starch granules (D3,2 ≈ 23 µm) were formed. The resulting hydrogel suspensions had similar appearances to starch pastes and could be made to have similar textural attributes (yield stress and shear viscosity) by adjusting the effective hydrogel particle concentration. These hydrogel particles may therefore be used to improve the texture of reduced-calorie foods and thereby help tackle obesity and diabetes.

  1. The interaction of streptococcal enolase with canine plasminogen: the role of surfaces in complex formation.

    Directory of Open Access Journals (Sweden)

    Vinod Balhara

    Full Text Available The enolase from Streptococcus pyogenes (Str enolase F137L/E363G is a homo-octamer shaped like a donut. Plasminogen (Pgn is a monomeric protein composed of seven discrete separated domains organized into a lock washer. The enolase is known to bind Pgn. In past work we searched for conditions in which the two proteins would bind to one another. The two native proteins in solution would not bind under any of the tried conditions. We found that if the structures were perturbed binding would occur. We stated that only the non-native Str enolase or Pgn would interact such that we could detect binding. We report here the results of a series of dual polarization interferometry (DPI experiments coupled with atomic force microscopy (AFM, isothermal titration calorimetry (ITC, dynamic light scattering (DLS, and fluorescence. We show that the critical condition for forming stable complexes of the two native proteins involves Str enolase binding to a surface. Surfaces that attract Str enolase are a sufficient condition for binding Pgn. Under certain conditions, Pgn adsorbed to a surface will bind Str enolase.

  2. Colorimetric determination of sildenafil citrate (Viagra) through ion-associate complex formation.

    Science.gov (United States)

    Amin, Alaa S; Moustafa, Moustafa E; El-Dosoky, Reham

    2009-01-01

    A simple, quick, accurate, and sensitive colorimetric method is described for the determination of sildenafil citrate (SLD). The method is based on the reaction of SLD with Congo Red, Sudan II, and Gentian Violet in buffered aqueous solutions at pH 2.5, 6.5, and 11.0, respectively, to give highly colored soluble ion-associate complex species; the colored products are quantitated colorimetrically at 523, 554, and 569 nm, respectively. The various experimental conditions were optimized. The stoichiometric ratio was found to be 1:1 for all ion associates; the calculated logarithmic stability constants were 8.51, 7.79, and 5.58, respectively. Beer's law was obeyed over the concentration range of 0.2-7.0 microg/mL, whereas the Ringbom optimum concentration range was 0.4-6.5 microg/mL. Values for molar absorptivity, Sandell sensitivity, and detection and quantification limits were also calculated. The proposed method was successfully applied to the determination of SLD in Viagra tablets and in serum samples by using the technique of standard additions with mean accuracy values of 100.06 +/- 1.14, 99.87 +/- 0.70, and 99.86 +/- 0.97% for Viagra tablets and 99.88 +/- 0.60, 99.90 +/- 0.90, and 100.24 +/- 0.80% for serum samples, respectively.

  3. Multi-Robot Coalitions Formation with Deadlines: Complexity Analysis and Solutions.

    Science.gov (United States)

    Guerrero, Jose; Oliver, Gabriel; Valero, Oscar

    2017-01-01

    Multi-robot task allocation is one of the main problems to address in order to design a multi-robot system, very especially when robots form coalitions that must carry out tasks before a deadline. A lot of factors affect the performance of these systems and among them, this paper is focused on the physical interference effect, produced when two or more robots want to access the same point simultaneously. To our best knowledge, this paper presents the first formal description of multi-robot task allocation that includes a model of interference. Thanks to this description, the complexity of the allocation problem is analyzed. Moreover, the main contribution of this paper is to provide the conditions under which the optimal solution of the aforementioned allocation problem can be obtained solving an integer linear problem. The optimal results are compared to previous allocation algorithms already proposed by the first two authors of this paper and with a new method proposed in this paper. The results obtained show how the new task allocation algorithms reach up more than an 80% of the median of the optimal solution, outperforming previous auction algorithms with a huge reduction of the execution time.

  4. Dynamic Modelling Reveals 'Hotspots' on the Pathway to Enzyme-Substrate Complex Formation.

    Directory of Open Access Journals (Sweden)

    Shane E Gordon

    2016-03-01

    Full Text Available Dihydrodipicolinate synthase (DHDPS catalyzes the first committed step in the diaminopimelate pathway of bacteria, yielding amino acids required for cell wall and protein biosyntheses. The essentiality of the enzyme to bacteria, coupled with its absence in humans, validates DHDPS as an antibacterial drug target. Conventional drug design efforts have thus far been unsuccessful in identifying potent DHDPS inhibitors. Here, we make use of contemporary molecular dynamics simulation and Markov state models to explore the interactions between DHDPS from the human pathogen Staphylococcus aureus and its cognate substrate, pyruvate. Our simulations recover the crystallographic DHDPS-pyruvate complex without a priori knowledge of the final bound structure. The highly conserved residue Arg140 was found to have a pivotal role in coordinating the entry of pyruvate into the active site from bulk solvent, consistent with previous kinetic reports, indicating an indirect role for the residue in DHDPS catalysis. A metastable binding intermediate characterized by multiple points of intermolecular interaction between pyruvate and key DHDPS residue Arg140 was found to be a highly conserved feature of the binding trajectory when comparing alternative binding pathways. By means of umbrella sampling we show that these binding intermediates are thermodynamically metastable, consistent with both the available experimental data and the substrate binding model presented in this study. Our results provide insight into an important enzyme-substrate interaction in atomistic detail that offers the potential to be exploited for the discovery of more effective DHDPS inhibitors and, in a broader sense, dynamic protein-drug interactions.

  5. The formation of host-guest complexes between surfactants and cyclodextrins.

    Science.gov (United States)

    Valente, Artur J M; Söderman, Olle

    2014-03-01

    Cyclodextrins are able to act as host molecules in supramolecular chemistry with applications ranging from pharmaceutics to detergency. Among guest molecules surfactants play an important role with both fundamental and practical applications. The formation of cyclodextrin/surfactant host-guest compounds leads to an increase in the critical micelle concentration and in the solubility of surfactants. The possibility of changing the balance between several intermolecular forces, and thus allowing the study of, e.g., dehydration and steric hindrance effects upon association, makes surfactants ideal guest molecules for fundamental studies. Therefore, these systems allow for obtaining a deep insight into the host-guest association mechanism. In this paper, we review the influence on the thermodynamic properties of CD-surfactant association by highlighting the effect of different surfactant architectures (single tail, double-tailed, gemini and bolaform), with special emphasis on cationic surfactants. This is complemented with an assessment of the most common analytical techniques used to follow the association process. The applied methods for computation of the association stoichiometry and stability constants are also reviewed and discussed; this is an important point since there are significant discrepancies and scattered data for similar systems in the literature. In general, the surfactant-cyclodextrin association is treated without reference to the kinetics of the process. However, there are several examples where the kinetics of the process can be investigated, in particular those where volumes of the CD cavity and surfactant (either the tail or in special cases the head group) are similar in magnitude. This will also be critically reviewed.

  6. In-situ formation of complex oxide precipitates during processing of oxide dispersion strengthened ferritic steels

    Energy Technology Data Exchange (ETDEWEB)

    Jayasankar, K., E-mail: jayasankar.met@gmail.com [CSIR-Institute of Minerals & Materials Technology, Bhubaneswar 751013 (India); Pandey, Abhishek [CSIR-Advanced Materials & Processes Research Institute, Bhopal 462026 (India); Mishra, B.K. [CSIR-Institute of Minerals & Materials Technology, Bhubaneswar 751013 (India); Das, Siddhartha [Indian Institute of Technology, Kharagpur 721302 (India)

    2016-01-15

    Highlights: • Use of dual drive planetary ball mill for Bench scale (>1 kg) production. • X-ray diffraction and TEM were used to study transformations during sintering. • HIPped and rolled samples with nearly 99% density successfully produced. - Abstract: In fusion and fission reactor material development, ODS alloys are the most suitable candidate materials due to its high temperature creep properties and irradiation resistance properties. This paper describes the preparation of oxide dispersion strengthened alloy powder in large quantity (>1 kg batch) in dual drive planetary ball mill using pre-alloyed ferrtic steel powder with nano sized Y{sub 2}O{sub 3}. The consolidation of the powders was carried out in hot isostatic press (HIP) followed by hot rolling. 99% of the theoretical density was achieved by this method. The vickers hardness values of pressed and rolled samples were in the range of 380 ± 2HV and 719 ± 2HV, respectively. Samples were further investigated using X-ray diffraction particle size analyzer and electron microscope. Initial increase in particle size with milling was observed showing flattening of the particle. It was found that 5 h of milling time is sufficient to reduce the particle size to achieve the desired size. Transmission electron microscopy analysis of milled ODS steel powder revealed a uniform distribution of combustion synthesized nano-Y{sub 2}O{sub 3} in ferritic steel matrix after a milling time of 5 h. Preliminary results demonstrated suitability of dual drive planetary ball mill for mass production of alloy within a short time due to various kinds of forces acting at a time during milling process. Fine monoclinic Y{sub 2}Si{sub 2}O{sub 7} precipitates were also observed in the steel. This study explains the particle characteristics of nano Y{sub 2}O{sub 3} dispersed ODS powder and formation of nano clusters in ODS ferritic alloy.

  7. Unique formation of two high-nuclearity metallamacrocycles from a mononuclear complex [Zn(dmpzdtc)2] (dmpzdtc=3,5-dimethylpyrazole-1-dithiocarboxylate) via CS2 elimination.

    Science.gov (United States)

    Li, Hong-Xi; Wu, Hua-Zhou; Zhang, Wen-Hua; Ren, Zhi-Gang; Zhang, Yong; Lang, Jian-Ping

    2007-12-21

    Dissolution of a mononuclear complex [Zn(dmpzdtc)2] in BrCH2CH2Br or DMF saturated with water followed by CS2 elimination led to the formation of two unique high-nuclearity metallamacrocyclic complexes, [Zn4(micro-dmpz)6(micro-OH)2]2 and [Zn4(micro-dmpz)6(micro-OH)2]4.

  8. Reaction of dimethyl ether with hydroxyl radicals: kinetic isotope effect and prereactive complex formation.

    Science.gov (United States)

    Bänsch, Cornelie; Kiecherer, Johannes; Szöri, Milan; Olzmann, Matthias

    2013-09-05

    The kinetic isotope effect of the reactions OH + CH3OCH3 (DME) and OH + CD3OCD3 (DME-d6) was experimentally and theoretically studied. Experiments were carried out in a slow-flow reactor at pressures between 5 and 21 bar (helium as bath gas) with production of OH by laser flash photolysis of HNO3 and time-resolved detection of OH by laser-induced fluorescence. The temperature dependences of the rate coefficients obtained can be described by the following modified Arrhenius expressions: k(OH+DME) = (4.5 ± 1.3) × 10(-16) (T/K)(1.48) exp(66.6 K/T) cm(3) s(-1) (T = 292-650 K, P = 5.9-20.9 bar) and k(OH+DME-d6) = (7.3 ± 2.2) × 10(-23) (T/K)(3.57) exp(759.8 K/T) cm(3) s(-1) (T = 387-554 K, P = 13.0-20.4 bar). A pressure dependence of the rate coefficients was not observed. The agreement of our experimental results for k(OH+DME) with values from other authors is very good, and from a fit to all available literature data, we derived the following modified Arrhenius expression, which reproduces the values obtained in the temperature range T = 230-1500 K at pressures between 30 mbar and 21 bar to better than within ±20%: k(OH+DME) = 8.45 × 10(-18) (T/K)(2.07) exp(262.2 K/T) cm(3) s(-1). For k(OH+DME-d6), to the best of our knowledge, this is the first experimental study. For the analysis of the reaction pathway and the kinetic isotope effect, potential energy diagrams were calculated by using three different quantum chemical methods: (I) CCSD(T)/cc-pV(T,Q)Z//MP2/6-311G(d,p), (II) CCSD(T)/cc-pV(T,Q)Z//CCSD/cc-pVDZ, and (III) CBS-QB3. In all three cases, the reaction is predicted to proceed via a prereaction OH-ether complex with subsequent intramolecular hydrogen abstraction and dissociation to give the methoxymethyl radical and water. Overall rate coefficients were calculated by assuming a thermal equilibrium between the reactants and the prereaction complex and by calculating the rate coefficients of the hydrogen abstraction step from canonical transition state theory

  9. Thermoacoustical analysis of solutions of poly(ethylene glycol) 200 through H-bond complex formation

    Energy Technology Data Exchange (ETDEWEB)

    Yasmin, Maimoona, E-mail: myasmin908@gmail.com [Department of Physics, University of Lucknow, Lucknow 226007 (India); Gupta, Manisha, E-mail: guptagm@rediffmail.com [Department of Physics, University of Lucknow, Lucknow 226007 (India)

    2011-05-10

    Research highlights: {yields} The presence of two electronegative elements viz. nitrogen and oxygen in its molecular architecture, ethanolamine has greater extent of interaction with PEG. {yields} Ethanolamine and m-cresol may be involved in a complex type of network of hydrogen bonding. {yields} Ethanolamine has greater extent of interaction with PEG than m-cresol and aniline particularly with least magnitude from aniline, where electron availability is least because of delocalization. {yields} The difference in molar volume between the components of the mixture control the mixture properties. - Abstract: Densities ({rho}) and ultrasonic velocities (u) of binary mixtures of poly(ethylene glycol) 200, PEG, with ethanolamine, m-cresol and aniline have been measured at various concentrations at 293.15, 303.15 and 313.15 K and have been fitted by third order polynomial equations at each temperature. The calculated values of isentropic compressibility (k{sub s}), free volume (V{sub f}), internal pressure ({pi}{sub i}), relaxation time ({tau}) and surface tension ({sigma}) at different mole fractions of PEG have been used to explain the hydrogen bonding and intermolecular interactions present in the mixture. Using these data, excess molar volume (V{sup E}), excess intermolecular free length (L{sub f}{sup E}), excess acoustic impedance (Z{sup E}) and excess pseudo-Grueneisen parameter ({Gamma}{sup E}) have been calculated and the results have been fitted to Redlich-Kister polynomial equation. All the results support each other and help in understanding the interactions in the mixture. Various models and mixing rules have been applied to evaluate the ultrasonic velocity data and have been compared with the experimental results.

  10. Soft matter strategies for controlling food texture: formation of hydrogel particles by biopolymer complex coacervation

    Science.gov (United States)

    Wu, Bi-cheng; Degner, Brian; McClements, David Julian

    2014-11-01

    Soft matter physics principles can be used to address important problems in the food industry. Starch granules are widely used in foods to create desirable textural attributes, but high levels of digestible starch may pose a risk of diabetes. Consequently, there is a need to find healthier replacements for starch granules. The objective of this research was to create hydrogel particles from protein and dietary fiber with similar dimensions and functional attributes as starch granules. Hydrogel particles were formed by mixing gelatin (0.5 wt%) with pectin (0 to 0.2 wt%) at pH values above the isoelectric point of the gelatin (pH 9, 30 °C). When the pH was adjusted to pH 5, the biopolymer mixture spontaneously formed micron-sized particles due to electrostatic attraction of cationic gelatin with anionic pectin through complex coacervation. Differential interference contrast (DIC) microscopy showed that the hydrogel particles were translucent and spheroid, and that their dimensions were determined by pectin concentration. At 0.01 wt% pectin, hydrogel particles with similar dimensions to swollen starch granules (D3,2 ≈ 23 µm) were formed. The resulting hydrogel suspensions had similar appearances to starch pastes and could be made to have similar textural attributes (yield stress and shear viscosity) by adjusting the effective hydrogel particle concentration. These hydrogel particles may therefore be used to improve the texture of reduced-calorie foods and thereby help tackle obesity and diabetes.

  11. Electrochemiluminescence detection of TNT by resonance energy transfer through the formation of a TNT-amine complex.

    Science.gov (United States)

    Qi, Wenjing; Xu, Min; Pang, Lei; Liu, Zhongyuan; Zhang, Wei; Majeed, Saadat; Xu, Guobao

    2014-04-14

    2,4,6-Trinitrotoluene (TNT) is a widely used nitroaromatic explosive with significant detrimental effects on the environment and human health. Its detection is of great importance. In this study, both electrochemiluminescence (ECL)-based detection of TNT through the formation of a TNT-amine complex and the detection of TNT through electrochemiluminescence resonance energy transfer (ECRET) are developed for the first time. 3-Aminopropyltriethoxysilane (APTES)-modified [Ru(phen)3](2+) (phen=1,10-phenanthroline)-doped silica nanoparticles (RuSiNPs) with uniform sizes of (73±3) nm were synthesized. TNT can interact with APTES-modified RuSiNPs through charge transfer from electron-rich amines in the RuSiNPs to the electron-deficient aromatic ring of TNT to form a red TNT-amine complex. The absorption spectrum of this complex overlaps with the ECL spectrum of the APTES-modified RuSiNPs/triethylamine system. As a result, ECL signals of the APTES-modified RuSiNPs/triethylamine system are turned off in the presence of TNT owing to resonance energy transfer from electrochemically excited RuSiNPs to the TNT-amine complex. This ECRET method has been successfully applied for the sensitive determination of TNT with a linear range from 1×10(-9) to 1×10(-6) M with a fast response time within 1 min. The limit of detection is 0.3 nM. The method exhibits good selectivity towards 2,4-dinitrotoluene, p-nitrotoluene, nitrobenzene, phenol, p-quinone, 8-hydroxyquinoline, p-phenylenediamine, K3[Fe(CN)6], Fe(3+), NO3(-), NO2(-), Cr(3+), Fe(2+), Pb(2+), SO3(2-), formaldehyde, oxalate, proline, and glycine.

  12. Complex formation between malate dehydrogenase and isocitrate dehydrogenase from Bacillus subtilis is regulated by tricarboxylic acid cycle metabolites.

    Science.gov (United States)

    Bartholomae, Maike; Meyer, Frederik M; Commichau, Fabian M; Burkovski, Andreas; Hillen, Wolfgang; Seidel, Gerald

    2014-02-01

    In Bacillus subtilis, recent in vivo studies revealed that particular enzymes of the tricarboxylic acid cycle form complexes that allow an efficient transfer of metabolites. Remarkably, a complex of the malate dehydrogenase (Mdh) (EC 1.1.1.37) with isocitrate dehydrogenase (Icd) (EC 1.1.1.42) was identified, although both enzymes do not catalyze subsequent reactions. In the present study, the interactions between these enzymes were characterized in vitro by surface plasmon resonance in the absence and presence of their substrates and cofactors. These analyses revealed a weak but specific interaction between Mdh and Icd, which was specifically stimulated by a mixture of substrates and cofactors of Icd: isocitrate, NADP(+) and Mg(2+). Wild-type Icd converted these substrates too fast, preventing any valid quantitative analysis of the interaction with Mdh. Therefore, binding of the IcdS104P mutant to Mdh was quantified because the mutation reduced the enzymatic activity by 174-fold but did not affect the stimulatory effect of substrates and cofactors on Icd-Mdh complex formation. The analysis of the unstimulated Mdh-IcdS104P interaction revealed kinetic constants of k(a) = 2.0 ± 0.2 × 10(2) m(-1) ·s(-1) and k(d) = 1.0 ± 0.1 × 10(-3) ·s(-1) and a K(D) value of 5.0 ± 0.1 μm. Addition of isocitrate, NADP(+) and Mg(2+) stimulated the affinity of IcdS104P to Mdh by 33-fold (K(D) = 0.15 ± 0.01 μm, k(a) = 1.7 ± 0.7 × 10(3) m(-1) ·s(-1), k(d) = 2.6 ± 0.6 × 10(-4) ·s(-1)). Analyses of the enzymatic activities of wild-type Icd and Mdh showed that Icd activity doubles in the presence of Mdh, whereas Mdh activity was slightly reduced by Icd. In summary, these data indicate substrate control of complex formation in the tricarboxylic acid cycle metabolon assembly and maintenance of the α-ketoglutarate supply for amino acid anabolism in vivo.

  13. The late Quaternary Diego Hernandez Formation, Tenerife: Volcanology of a complex cycle of voluminous explosive phonolitic eruptions

    Science.gov (United States)

    Edgar, C. J.; Wolff, J. A.; Olin, P. H.; Nichols, H. J.; Pittari, A.; Cas, R. A. F.; Reiners, P. W.; Spell, T. L.; Martí, J.

    2007-02-01

    The Diego Hernandez Formation (DHF; 600-ca. 180 ka) represents the products of the most recent complete cycle of phonolitic explosive volcanism on Tenerife (Canary Islands, Spain). We provide a revised and detailed stratigraphy, new 40Ar/ 39Ar and (U-Th)/He age determinations for major eruptive units, a summary of new chemical data and an overview of the key characteristics of the cycle, including volume estimates, dispersal patterns, eruption styles, phreatomagmatic influences and caldera collapse episodes. The complex stratigraphy of the DHF is divided into 20 named members, each representing a major eruption, as well as numerous unnamed members of limited present-day exposure. The major eruptions are represented by the Fortaleza (370 ka), Roque (347 ka, 3 km 3), Aldea (319 ka, 3 km 3), Fasnia (309 ka, 13 km 3), Poris (268 ka, 3.5 km 3), Arafo (4 km 3), Caleta (223 ka, 3.5 km 3) and Abrigo (between 196 and 171 ka, 20 km 3) Members. The Aldea, Fasnia and Poris Members consist of highly complex successions of plinian fall, surge and flow deposits and several of the eruptions produced widespread and internally complex ignimbrite sheets. Phreatomagmatism occurred most frequently in the opening phase of the eruptions but also recurred repeatedly throughout many of the sequences. Inferred sources of water include a shallow caldera lake and groundwater, and intermittent phreatomagmatic activity was an important influence on eruption style. Another important factor was conduit and vent instability, which frequently loaded the eruption column with dense lithic debris and occasionally triggered column collapse and ignimbrite formation. Most of the major DHF eruptions were triggered by injection of mafic magma into existing phonolitic magma bodies. Two phonolitic magma types were available for eruption during the lifetime of the DHF, but each was dominant at different times. The results presented here support a caldera collapse rather than a landslide model for the origin

  14. Cerimetric determination of simvastatin in pharmaceuticals based on redox and complex formation reactions

    Energy Technology Data Exchange (ETDEWEB)

    Basavaiah, K.; Devi, O.Z [University of Mysore, Manasagangotri, Mysore (India). Dept. of Chemistry]. E-mail: basavaiahk@yahoo.co.in

    2008-07-01

    Two sensitive spectrophotometric methods are described for the determination of simvastatin (SMT) in bulk drug and in tablets. The methods are based on the oxidation of SMT by a measured excess of cerium (IV) in acid medium followed by determination of unreacted oxidant by two different reaction schemes. In one procedure (method A), the residual cerium (IV) is reacted with a fixed concentration of ferroin and the increase in absorbance is measured at 510 nm. The second approach (method B) involves the reduction of the unreacted cerium (IV) with a fixed quantity of iron (II), and the resulting iron (III) is complexed with thiocyanate and the absorbance measured at 470 nm. In both methods, the amount of cerium (IV) reacted corresponds to SMT concentration. The experimental conditions for both methods were optimized. In method A, the absorbance is found to increase linearly with SMT concentration (r = 0.9995) whereas in method B, the same decreased (r = -0.9943). The systems obey Beer's law for 0.6-7.5 and 0.5-5.0 {mu}g mL{sup -1} for method A and method B, respectively. The calculated molar absorptivity values are 2.7 X 104 and 1.06 X 105 Lmol{sup -1} cm{sup -1}, respectively; and the corresponding sandel sensitivity values are 0.0153 and 0.0039 {mu}g cm{sup -2}, respectively. The limit of detection (LOD) and quantification (LOQ) are reported for both methods. Intra-day and inter-day precision, and accuracy of the methods were established as per the current ICH guidelines. The methods were successfully applied to the determination of SMT in tablets and the results were statistically compared with those of the reference method by applying the Student's t-test and F-test. No interference was observed from the common excipients added to tablets. The accuracy and validity of the methods were further ascertained by performing recovery experiments via standard addition procedure. (author)

  15. Micellar effect on the sensitivity of spectrophotometric Mo(VI) determination based on the formation of gallic acid complex providing evidence for the polyoxoanion structure of molybdate ions

    Energy Technology Data Exchange (ETDEWEB)

    Tascioglu, Senay [Department of Chemistry, Faculty of Arts and Sciences, Gazi University, Ankara (Turkey)]. E-mail: senaytas@gazi.edu.tr; Sendil, Olcay [Department of Chemistry, Faculty of Arts and Sciences, Gazi University, Ankara (Turkey); Beyreli, Sivekar [Department of Chemistry, Faculty of Arts and Sciences, Gazi University, Ankara (Turkey)

    2007-05-08

    In this study effects of anionic (sodium dodecyl sulfate, SDS), cationic (cetyltrimethylammonium bromide, CTAB) and nonionic (Triton X-100, TX100) micelles on the sensitivity of spectrophotometric molybdenum(VI) (Mo) determination based on the formation of a binary complex with gallic acid (GA) were investigated. Micellar CTAB was found to enhance the formation of Mo-GA complex. SDS micelles exerted an inhibitory effect while TX100 micelles had no effect on the complex formation. By the optimization of experimental conditions, the determination limit of the method suggested in the literature was lowered from 5.2 x 10{sup -5} to 4.6 x 10{sup -6} and to 5.7 x 10{sup -7} M, in the absence and presence of CTAB, respectively. The mechanism of the effect of CTAB was investigated by spectrophotometric titrations and it was concluded that CTAB did not form a ternary complex with Mo and GA. The stoichiometry of the complex, deduced from the results of spectrophotometric titrations, provided evidence for the formation of para-Mo{sub 7}O{sub 4} {sup 6-} polyanions at pH 4.5, indicating to the formation of a charge transfer complex between these ions and GA in micellar medium.

  16. Study of inclusion complex formation between tropaeolin OO and beta-cyclodextrin by spectrophotometry and Infrared spectroscopy.

    Science.gov (United States)

    Wang, Huai You; Han, Juan; Feng, Xia Guang; Pang, Yan Ling

    2006-09-01

    The mechanism of the inclusion of tropaeolin OO (TPOO) and beta-cyclodextrin (beta-CD) has been studied by spectrophotometry. The inclusion depth of the guest molecule in the host molecule was demonstrated by infrared spectrometry. Effect of the pH, concentrations of beta-CD, solvents and ionic strength on the inclusion of TPOO and beta-CD were examined. The result showed that TPOO reacts with beta-CD to form a 1:1 host-guest complex with an apparent formation constant of 1.50 x 10(3) l mol(-1). The thermodynamic parameters of inclusion reaction, DeltaG degrees , DeltaH degrees and DeltaS degrees were obtained.

  17. Protons and Mg2+ cations as probes in investigating the role of GTP in initiation complex formation.

    Science.gov (United States)

    Beaudry, P; Begard, E; Douzou, P; Grunberg-Manago, M

    1978-12-01

    fMet-tRNAfMet binding to both 30-S subunits and to 70-S particles is dependent on both pH AND Mg2+ concentration: for fMet-tRNAfMet binding to 70-S particles, variations of pH and Mg2+ concentration are tightly interdependent. This behavior can be interpreted by the polyelectrolyte theory as a direct consequence of the fact that the binding occurs in a polyanionic micro-environment. The pH-dependent binding to 70-S particles clearly shows the involvement of two prototropic groups which appear to be those carrying out GTP hydrolysis, therefore directly linked to initiation complex formation; in the presence of a non-hydrolyzable analogue to GTP, guanosine 5'-[beta, gamma-imido]triphosphate, the binding of fMet-tRNAfMet shows much less interdependence between variation of pH and Mg2+ concentration.

  18. Complex formation of CdSe/ZnS/TOPO nanocrystal vs. molecular chaperone in aqueous solution by hydrophobic interaction

    Energy Technology Data Exchange (ETDEWEB)

    Horiuchi, Hiromi [Department of Applied Physics, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Kogane-i, Tokyo 184-8588 (Japan)]. E-mail: horihiro@cc.tuat.ac.jp; Iwami, Noriya [Department of Applied Physics, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Kogane-i, Tokyo 184-8588 (Japan); Tachibana, Fumi [Department of Applied Physics, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Kogane-i, Tokyo 184-8588 (Japan); Ohtaki, Akashi [Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Kogane-i, Tokyo 184-8588 (Japan); Iizuka, Ryo [Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Kogane-i, Tokyo 184-8588 (Japan); Zako, Tamotsu [Bioengineering Laboratory, RIKEN - Institute of Physical and Chemical Research, 2-1, Hirosawa, Wako, Saitama 351-0198 (Japan); Oda, Masaru [Department of Applied Physics, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Kogane-i, Tokyo 184-8588 (Japan); Strategic Research Initiative for Future Nano-Science and Technology, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Kogane-i, Tokyo 184-8588 (Japan); Yohda, Masafumi [Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Kogane-i, Tokyo 184-8588 (Japan); Strategic Research Initiative for Future Nano-Science and Technology, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Kogane-i, Tokyo 184-8588 (Japan); Tani, Toshiro [Department of Applied Physics, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Kogane-i, Tokyo 184-8588 (Japan); Strategic Research Initiative for Future Nano-Science and Technology, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Kogane-i, Tokyo 184-8588 (Japan)

    2007-11-15

    Feasibilities to stabilize CdSe/ZnS/trioctylphosphineoxide (TOPO) nanocrystals (quantum dots, QDs) in aqueous solutions with prefoldin macromolecules in their bioactive states are reported. Prefoldin is a jellyfish-shaped hexameric co-chaperone of the group II chaperonins. As a protein folding intermediate is captured within its central cavity, so CdSe/ZnS/TOPO QDs would also be included within this cavity. It is also found the QDs can be much more dispersed in aqueous solutions and suspended for certain period of time by adding trace amount of t-butanol in the buffer prior to the mixing of the QDs mother solution. While biochemical procedures are evaluated with ordinary fluorescence measurements, possible complex formations are also evaluated with TIRFM single-molecule detection techniques.

  19. Formation and characterization of thin films from phthalocyanine complexes: An electrosynthesis study using the atomic-force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Vergara, M.E. [Departamento de Ingenieria Mecatronica, Escuela de Ingenieria, Universidad Anahuac del Norte, Avenida Lomas de la Anahuac s/n, Col. Lomas Anahuac, 52786, Huixquilucan (Mexico)]. E-mail: elena.sanchez@anahuac.mx; Islas Bernal, I.F. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, 04510, Mexico D.F. (Mexico); Rivera, M. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, 04510, Mexico D.F. (Mexico); Ortiz Rebollo, A. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, A.P. 70-360, Coyoacan, 04510, Mexico, D.F. (Mexico); Alvarez Bada, J.R. [Instituto Tecnologico y de Estudios Superiores de Monterrey, Campus Ciudad de Mexico, Calle del Puente 222, Col. Ejidos de Huipulco, 14380, Mexico D.F. (Mexico)

    2007-05-07

    ({mu}-Cyano)(phthalocyaninato)metal(III) [PcMCN]{sub n} species with a central transition metal ion, such as Fe(III) and Co(III), were used to prepare molecular films on a highly oriented pyrolytic graphite electrode substrate by using the cyclic voltammetry technique. In order to investigate the influence of the ligand on the film properties, 1,8-dihydroxyanthraquinone and 2,6-dihydroxyanthraquinone as bivalent ligands were employed. The structure of the molecular materials was analyzed by infrared spectroscopy. The in situ film formation, texture, composition and conductivity of each film were further investigated using atomic force microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and the four-probe technique, respectively. The [PcMCN]{sub n} complexes provided conductive films with an electrical conductivity of 1 x 10{sup -6} {omega}{sup -1} cm{sup -1} at 298 K.

  20. Thermodynamics of complexes formation by ITC in methanol/water = 9/1 (v/v) solution: A case study

    Energy Technology Data Exchange (ETDEWEB)

    Fisicaro, Emilia, E-mail: emilia.fisicaro@unipr.it [University of Parma, Department of Pharmacy, Parco Area delle Scienze, 27/A, 43124 Parma (Italy); Compari, Carlotta; Bacciottini, Franco; Contardi, Laura [University of Parma, Department of Pharmacy, Parco Area delle Scienze, 27/A, 43124 Parma (Italy); Carcelli, Mauro; Rispoli, Gabriele; Rogolino, Dominga [University of Parma, Department of Chemistry, Parco Area delle Scienze, 17/A, 43124 Parma (Italy)

    2014-06-01

    Graphical abstract: Integrase strand transfert inhibitors chelate the metal ions in the active site of HIV integrase. - Highlights: • Development of inhibitors acting against those viral enzymes operating via a cooperative two-metal ion mechanism, such as HIV integrase (IN), requires optimizing the binding affinity to the target. • We have defined an experimental procedure for obtaining reliable thermodynamic data by ITC in methanol/water = 9/1 (v/v) as solvent. • Formation heats in mixed solvent of the complexes formed by a ligand, model of Raltegravir, with Mg(II), Mn(II), Co(II) and Zn(II) are here reported. - Abstract: Most enzymes that participate in the biochemistry of nucleic acids require divalent metal ion cofactors to promote activity. Development of potent inhibitors, acting against those viral enzymes operating via a cooperative two-metal ion mechanism, such as HIV integrase (IN) and RNase H, hepatitis C virus polymerase and influenza endonuclease, requires optimizing the binding affinity to the target, which is dictated by the binding free energy composed of both enthalpic and entropic contributions. They can be obtained by using isothermal titration microcalorimetry. We have defined an experimental procedure for obtaining reliable thermodynamic data in methanol/water = 9/1 0.1 M KCl as solvent, used to overcome solubility problems. In this way we have measured the heats of formation of the complexes formed by N-(4-fluorobenzyl)-5-hydroxy-2-isopropyl-1-methyl-6-oxo-1, 6-dihydroxypyrimidine-4-carboxylate (HL, a model of Raltegravir, the antiretroviral drug produced by Merck and Co.), and a series of divalent metal ions of biological interest (Mg(II), Mn(II), Co(II) and Zn(II)), whose speciation was previously determined by potentiometry.

  1. Extracellular Fibrinogen-binding Protein (Efb) from Staphylococcus aureus Inhibits the Formation of Platelet-Leukocyte Complexes.

    Science.gov (United States)

    Posner, Mareike G; Upadhyay, Abhishek; Abubaker, Aisha Alsheikh; Fortunato, Tiago M; Vara, Dina; Canobbio, Ilaria; Bagby, Stefan; Pula, Giordano

    2016-02-05

    Extracellular fibrinogen-binding protein (Efb) from Staphylococcus aureus inhibits platelet activation, although its mechanism of action has not been established. In this study, we discovered that the N-terminal region of Efb (Efb-N) promotes platelet binding of fibrinogen and that Efb-N binding to platelets proceeds via two independent mechanisms: fibrinogen-mediated and fibrinogen-independent. By proteomic analysis of Efb-interacting proteins within platelets and confirmation by pulldown assays followed by immunoblotting, we identified P-selectin and multimerin-1 as novel Efb interaction partners. The interaction of both P-selectin and multimerin-1 with Efb is independent of fibrinogen. We focused on Efb interaction with P-selectin. Excess of P-selectin extracellular domain significantly impaired Efb binding by activated platelets, suggesting that P-selectin is the main receptor for Efb on the surface of activated platelets. Efb-N interaction with P-selectin inhibited P-selectin binding to its physiological ligand, P-selectin glycoprotein ligand-1 (PSGL-1), both in cell lysates and in cell-free assays. Because of the importance of P-selectin-PSGL-1 binding in the interaction between platelets and leukocytes, we tested human whole blood and found that Efb abolishes the formation of platelet-monocyte and platelet-granulocyte complexes. In summary, we present evidence that in addition to its documented antithrombotic activity, Efb can play an immunoregulatory role via inhibition of P-selectin-PSGL-1-dependent formation of platelet-leukocyte complexes.

  2. Synthesis of Reusable Silica Nanosphere-Supported Pt(IV Complex for Formation of Disulfide Bonds in Peptides

    Directory of Open Access Journals (Sweden)

    Xiaonan Hou

    2017-02-01

    Full Text Available Some peptide-based drugs, including oxytocin, vasopressin, ziconotide, pramlintide, nesiritide, and octreotide, contain one intramolecular disulfide bond. A novel and reusable monodispersed silica nanosphere-supported Pt(IV complex (SiO2@TPEA@Pt(IV; TPEA: N-[3-(trimethoxysilylpropyl]ethylenediamine was synthesized via a four-step procedure and was used for the formation of intramolecular disulfide bonds in peptides. Transmission electron microscopy (TEM and chemical mapping results for the Pt(II intermediates and for SiO2@TPEA@Pt(IV show that the silica nanospheres possess a monodisperse spherical structure and contain uniformly-distributed Si, O, C, N, Cl, and Pt. The valence state of Pt on the silica nanospheres was characterized by X-ray photoelectron spectroscopy (XPS. The Pt(IV loaded on SiO2@TPEA@Pt(IV was 0.15 mmol/g, as determined by UV-VIS spectrometry. The formation of intramolecular disulfides in six dithiol-containing peptides of variable lengths by the use of SiO2@TPEA@Pt(IV was investigated, and the relative oxidation yields were determined by high-performance liquid chromatography (HPLC. In addition, peptide 1 (Ac-CPFC-NH2 was utilized to study the reusability of SiO2@TPEA@Pt(IV. No significant decrease in the relative oxidation yield was observed after ten reaction cycles. Moreover, the structure of SiO2@TPEA@Pt(IV after being used for ten cycles was determined to be similar to its initial one, demonstrating the cycling stability of the complex.

  3. Directional R-Loop Formation by the CRISPR-Cas Surveillance Complex Cascade Provides Efficient Off-Target Site Rejection

    Directory of Open Access Journals (Sweden)

    Marius Rutkauskas

    2015-03-01

    Full Text Available CRISPR-Cas systems provide bacteria and archaea with adaptive immunity against foreign nucleic acids. In type I CRISPR-Cas systems, invading DNA is detected by a large ribonucleoprotein surveillance complex called Cascade. The crRNA component of Cascade is used to recognize target sites in foreign DNA (protospacers by formation of an R-loop driven by base-pairing complementarity. Using single-molecule supercoiling experiments with near base-pair resolution, we probe here the mechanism of R-loop formation and detect short-lived R-loop intermediates on off-target sites bearing single mismatches. We show that R-loops propagate directionally starting from the protospacer-adjacent motif (PAM. Upon reaching a mismatch, R-loop propagation stalls and collapses in a length-dependent manner. This unambiguously demonstrates that directional zipping of the R-loop accomplishes efficient target recognition by rapidly rejecting binding to off-target sites with PAM-proximal mutations. R-loops that reach the protospacer end become locked to license DNA degradation by the auxiliary Cas3 nuclease/helicase without further target verification.

  4. The Human SepSecS-tRNA[superscript Sec] Complex Reveals the Mechanism of Selenocysteine Formation

    Energy Technology Data Exchange (ETDEWEB)

    Palioura, Sotiria; Sherrer, R. Lynn; Steitz, Thomas A.; Söll, Dieter; Simonovic, Miljan; (Yale); (UIC)

    2009-08-13

    Selenocysteine is the only genetically encoded amino acid in humans whose biosynthesis occurs on its cognate transfer RNA (tRNA). O-Phosphoseryl-tRNA:selenocysteinyl-tRNA synthase (SepSecS) catalyzes the final step of selenocysteine formation by a poorly understood tRNA-dependent mechanism. The crystal structure of human tRNA{sup Sec} in complex with SepSecS, phosphoserine, and thiophosphate, together with in vivo and in vitro enzyme assays, supports a pyridoxal phosphate-dependent mechanism of Sec-tRNA{sup Sec} formation. Two tRNA{sup Sec} molecules, with a fold distinct from other canonical tRNAs, bind to each SepSecS tetramer through their 13-base pair acceptor-T{Upsilon}C arm (where {Upsilon} indicates pseudouridine). The tRNA binding is likely to induce a conformational change in the enzyme's active site that allows a phosphoserine covalently attached to tRNA{sup Sec}, but not free phosphoserine, to be oriented properly for the reaction to occur.

  5. Steady state and time-resolved fluorescence spectroscopy of quinine sulfate dication bound to sodium dodecylsulfate micelles: Fluorescent complex formation

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Sunita; Pant, Debi D., E-mail: ddpant@pilani.bits-pilani.ac.in

    2014-01-15

    Interaction of quinine sulfate dication (QSD) with anionic, sodium dodecylsulphate (SDS) surfactant has been studied at different premicellar, micellar and postmicellar concentrations in aqueous phase using steady state, time-resolved fluorescence and fluorescence anisotropy techniques. At premicellar concentrations of SDS, the decrease in absorbance, appearance of an extra fluorescence band at lower wavelengths and tri-exponential decay behavior of fluorescence, are attributed to complex formation between QSD molecules and surfactant monomers. At postmicellar concentrations the red shift in fluorescence spectrum, increase in quantum yield and increase in fluorescence lifetimes are attributed to incorporation of solute molecules to micelles. At lower concentrations of SDS, a large shift in fluorescence is observed on excitation at the red edge of absorption spectrum and this is explained in terms of distribution of ion pairs of different energies in the ground state and the observed fluorescence lifetime behavior corroborates with this model. The temporal fluorescence anisotropy decay of QSD in SDS micelles allowed determination of restriction on the motion of the fluorophore. All the different techniques used in this study reveal that the photophysics of QSD is very sensitive to the microenvironments of SDS micelles and QSD molecules reside at the water-micelle interface. -- Highlights: • Probe molecule is very sensitive to microenvironment of micelles. • Highly fluorescent ion-pair formation has been observed. • Modulated photophysics of probe molecule in micellar solutions has been observed. • Probe molecules strongly bind with micelles and reside at probe–micelle interface.

  6. Local development and globalization: the case of the formation of the agroindustrial complex of lemon in Colima, México

    Directory of Open Access Journals (Sweden)

    Saúl Martínez González

    2008-03-01

    Full Text Available The multinational company has been the main vehicle of internationalization of capital and trade integration between countries. The global expansion phase of the transnational corporation is associated with the hegemony of capitalism in the United States, whose influence has been decisive in the territories where it operates. This essay is a case of the influence of transnational company Coca Cola in the formation of the region of Tecoman, Colima, as providing an input to the company during the period dominated by Fordism. This region is formed from exogenous impulses of the needs of lemon essential oil by transnational companies which in turn have determined the stages of growth and expansion in the region that occur in phases of boom and bust. Dependence on oil exports Mexican lime by an American multinational company is determined, in turn, by the behavior of the economic cycle in the United States. This study highlights the stage of formation of the agroindustrial complex and does not attempt to analyze the current situation

  7. Ternary complex formation between AmtB, GlnZ and the nitrogenase regulatory enzyme DraG reveals a novel facet of nitrogen regulation in bacteria.

    Science.gov (United States)

    Huergo, Luciano F; Merrick, Mike; Pedrosa, Fábio O; Chubatsu, Leda S; Araujo, Luíza M; Souza, Emanuel M

    2007-12-01

    Ammonium movement across biological membranes is facilitated by a class of ubiquitous channel proteins from the Amt/Rh family. Amt proteins have also been implicated in cellular responses to ammonium availability in many organisms. Ammonium sensing by Amt in bacteria is mediated by complex formation with cytosolic proteins of the P(II) family. In this study we have characterized in vitro complex formation between the AmtB and P(II) proteins (GlnB and GlnZ) from the diazotrophic plant-associative bacterium Azospirillum brasilense. AmtB-P(II) complex formation only occurred in the presence of adenine nucleotides and was sensitive to 2-oxoglutarate when Mg(2+) and ATP were present, but not when ATP was substituted by ADP. We have also shown in vitro complex formation between GlnZ and the nitrogenase regulatory enzyme DraG, which was stimulated by ADP. The stoichiometry of this complex was 1:1 (DraG monomer : GlnZ trimer). We have previously reported that in vivo high levels of extracellular ammonium cause DraG to be sequestered to the cell membrane in an AmtB and GlnZ-dependent manner. We now report the reconstitution of a ternary complex involving AmtB, GlnZ and DraG in vitro. Sequestration of a regulatory protein by the membrane-bound AmtB-P(II) complex defines a new regulatory role for Amt proteins in Prokaryotes.

  8. Formation of metamorphic core complexes in non-over-thickened continental crust: A case study of Liaodong Peninsula (East Asia)

    Science.gov (United States)

    Wang, Kun; Burov, Evgueni; Gumiaux, Charles; Chen, Yan; Lu, Gang; Mezri, Leila; Zhao, Liang

    2015-12-01

    Pre-thickened hot orogenic crust is often considered a necessary condition for the formation of continental metamorphic core complexes (MCCs). However, the discovery of MCCs in the Liaodong Peninsula, where the crust has a normal thickness (~ 35 km), challenges the universality of this scenario. Therefore, we implement a series of 2-D numerical thermo-mechanical modeling experiments in which we investigate the conditions of MCC formation in normal crusts, as well as the relationships between the underlying mechanisms and the syn-rift basin evolution. In these experiments, we explore the impact of the lithostratigraphic and thermo-rheological structure of the crust. We also examine the lithosphere thickness, strain softening, extension rate, and surface erosion/ sedimentation processes. The experiments demonstrate that high thermal gradients and crustal heterogeneities result only in a symmetric spreading dome, which is geometrically incompatible with the observations of the MCCs in the Liaodong Peninsula. According to our further findings, the strain softening should play a key role in the development of asymmetric strain localization and domal topography uplift, while synchronous surface erosion controls the polarity of the syn-rift basin. The synthetic model data are compatible with the geological observations and cooling history based on the thermo-chronology for the eastern part of the East Asia during the late Mesozoic to the early Cenozoic. The model-predicted P-T-t paths are essentially different from those inferred for the other known MCCs, confirming the exceptional character of the MCC formation in the wide rift system of the East Asia.

  9. Auditory Scene Analysis and sonified visual images. Does consonance negatively impact on object formation when using complex sonified stimuli?

    Directory of Open Access Journals (Sweden)

    David J Brown

    2015-10-01

    Full Text Available A critical task for the brain is the sensory representation and identification of perceptual objects in the world. When the visual sense is impaired, hearing and touch must take primary roles and in recent times compensatory techniques have been developed that employ the tactile or auditory system as a substitute for the visual system. Visual-to-auditory sonifications provide a complex, feature-based auditory representation that must be decoded and integrated into an object-based representation by the listener. However, we don’t yet know what role the auditory system plays in the object integration stage and whether the principles of auditory scene analysis apply. Here we used coarse sonified images in a two-tone discrimination task to test whether auditory feature-based representations of visual objects would be confounded when their features conflicted with the principles of auditory consonance. We found that listeners (N = 36 performed worse in an object recognition task when the auditory feature-based representation was harmonically consonant. We also found that this conflict was not negated with the provision of congruent audio-visual information. The findings suggest that early auditory processes of harmonic grouping dominate the object formation process and that the complexity of the signal, and additional sensory information have limited effect on this.

  10. Auditory scene analysis and sonified visual images. Does consonance negatively impact on object formation when using complex sonified stimuli?

    Science.gov (United States)

    Brown, David J; Simpson, Andrew J R; Proulx, Michael J

    2015-01-01

    A critical task for the brain is the sensory representation and identification of perceptual objects in the world. When the visual sense is impaired, hearing and touch must take primary roles and in recent times compensatory techniques have been developed that employ the tactile or auditory system as a substitute for the visual system. Visual-to-auditory sonifications provide a complex, feature-based auditory representation that must be decoded and integrated into an object-based representation by the listener. However, we don't yet know what role the auditory system plays in the object integration stage and whether the principles of auditory scene analysis apply. Here we used coarse sonified images in a two-tone discrimination task to test whether auditory feature-based representations of visual objects would be confounded when their features conflicted with the principles of auditory consonance. We found that listeners (N = 36) performed worse in an object recognition task when the auditory feature-based representation was harmonically consonant. We also found that this conflict was not negated with the provision of congruent audio-visual information. The findings suggest that early auditory processes of harmonic grouping dominate the object formation process and that the complexity of the signal, and additional sensory information have limited effect on this.

  11. Star formation and chemical complexity in the Orion nebula: A new view with the IRAM and ALMA interferometers

    Science.gov (United States)

    Baudry, Alain; Brouillet, Nathalie; Despois, Didier

    2016-11-01

    The Orion nebula is one of the most observed celestial regions in the Milky Way. It is an active massive star-forming region, especially well studied in the millimeter and submillimeter domains that allow us to unveil the cool and obscured regions in which stars are being formed. After a brief introduction to the main properties of a radio telescope, we recall that the most sensitive radio interferometers, the IRAM mm array and, especially, the recently built ALMA millimeter/submillimeter array, offer an outstanding spatial resolution reaching the sub-arcsecond scale, or even about 10 milli-arcseconds for ALMA (about four times the Earth's orbit radius at the Orion distance). These interferometers can reveal the fine spatial details of the Orion clouds of gas and dust within which new stars and associated planetary systems are being formed. The high spectral resolution and sensitivity of both interferometers and the broad instantaneous bandwidth offered by ALMA allowed us to map the emission from a number of complex organic molecules, to estimate the molecular abundances, and to address some important aspects of the molecular complexity in Orion. Our observations do not lead to a unique molecular formation and excitation scheme, but the chemistry at work in the proto-stellar 'fragments' at the center of the Orion nebula can be compared with the chemistry prevailing in comets of the Solar system. We have underlined the possible links between the prebiotic molecules observed in space and the chemistry leading to the early terrestrial life.

  12. FRK inhibits migration and invasion of human glioma cells by promoting N-cadherin/β-catenin complex formation.

    Science.gov (United States)

    Shi, Qiong; Song, Xu; Wang, Jun; Gu, Jia; Zhang, Weijian; Hu, Jinxia; Zhou, Xiuping; Yu, Rutong

    2015-01-01

    Fyn-related kinase (FRK), a member of Src-related tyrosine kinases, is recently reported to function as a potent tumor suppressor in several cancer types. Our previous study has also shown that FRK over-expression inhibited the migration and invasion of glioma cells. However, the mechanism of FRK effect on glioma cell migration and invasion, a feature of human malignant gliomas, is still not clear. In this study, we found that FRK over-expression increased the protein level of N-cadherin, but not E-cadherin. Meanwhile, FRK over-expression promoted β-catenin translocation to the plasma membrane, where it formed complex with N-cadherin, while decreased β-catenin level in the nuclear fraction. In addition, down-regulation of N-cadherin by siRNA promoted the migration and invasion of glioma U251 and U87 cells and abolished the inhibitory effect of FRK on glioma cell migration and invasion. In summary, these results indicate that FRK inhibits migration and invasion of human glioma cells by promoting N-cadherin/β-catenin complex formation.

  13. Formation of transgressive anorthosite seams in the Bushveld Complex via tectonically induced mobilisation of plagioclase-rich crystal mushes

    Institute of Scientific and Technical Information of China (English)

    Wolfgang D. Maier; Bartosz T. Karykowski; Sheng-Hong Yang

    2016-01-01

    The formation of anorthosites in layered intrusions has remained one of petrology’s most enduring enigmas. We have studied a sequence of layered chromitite, pyroxenite, norite and anorthosite overlying the UG2 chromitite in the Upper Critical Zone of the eastern Bushveld Complex at the Smokey Hills platinum mine. Layers show very strong medium to large scale lateral continuity, but abundant small scale irregularities and transgressive relationships. Particularly notable are irregular masses and seams of anorthosite that have intrusive relationships to their host rocks. An anorthosite layer locally transgresses several 10 s of metres into its footwall, forming what is referred to as a “pothole” in the Bushveld Complex. It is proposed that the anorthosites formed from plagioclase-rich crystal mushes that originally accumulated at or near the top of the cumulate pile. The slurries were mobilised during tectonism induced by chamber subsidence, a model that bears some similarity to that generally proposed for oceanic mass flows. The anorthosite slurries locally collapsed into pull-apart structures and injected their host rocks. The final step was down-dip drainage of Fe-rich intercumulus liquid, leaving behind anor-thosite adcumulates.

  14. CLUSTER CONCEPT AS INSTITUTIONAL BASIS OF FORMATION OF THE INNOVATIVE ENVIRONMENT OF THE OIL AND GAS COMPLEX

    Directory of Open Access Journals (Sweden)

    Bondarenko K. S.

    2015-10-01

    Full Text Available The article represents the author's view on the issue of formation of innovative environment in the oil and gas industry through clustering. The main task of the author is, on the one hand, clusters’ role justification in optimization of organizational structure of regional fuel and energy complex. On the other hand, it is a justification of the state's functions in ensuring the intensification of innovation. To solve this complex problem the author explores the approaches to the definition of "cluster", adapting existing theories to clustering of the regional to the oil and gas sector. There are the structural-logic "Competitive diamond" Russian oil cluster "and" Competitive diamond "oil cluster Russia." The author 'classification of innovations in the energy sector is developed. The question of revitalization of the state’s efforts to build a favorable innovation environment was considered based on several logical promises. The first, public policy objectives to stimulate investment in innovation are substantiated. Second, we studied directions of transformation of the global energy market and their impact on the economic security of Russia as oil exporters. Separately, the emphasis is placed on fiscal policy in the energy sector

  15. Stereoselective formation and catalytic activity of hydrido(acylphosphane)(chlorido)(pyrazole)rhodium(III) complexes. Experimental and DFT studies.

    Science.gov (United States)

    San Nacianceno, Virginia; Azpeitia, Susan; Ibarlucea, Lourdes; Mendicute-Fierro, Claudio; Rodríguez-Diéguez, Antonio; Seco, José M; San Sebastian, Eider; Garralda, María A

    2015-08-07

    The reaction of [{RhCl(COD)}2] (COD = 1,5-cyclooctadiene) with L = pyrazole (Hpz), 3(5)-methylpyrazole (Hmpz) or 3,5-dimethylpyrazole (Hdmpz) and PPh2(o-C6H4CHO) (Rh : L : P = 1 : 2 : 1) gives hydridoacyl complexes [RhHCl{PPh2(o-C6H4CO)}(L)2] (). Stereoselective formation of and with pyrazoles trans to hydrido and phosphorus and hydrogen bond formation with O-acyl and chlorido occur. is a mixture of two linkage isomers in a 9 : 1 ratio, with two 5-methylpyrazole ligands or with one 3- and one 5-methylpyrazole ligand, respectively. Fluxional undergoes metallotropic tautomerization and is a mixture of equal amounts of and , with hydrido trans to pyrazole or chlorido, respectively. Complexes readily exchange hydrido by chlorido to afford [RhCl2{PPh2(o-C6H4CO)}(L)2] (, and ) as single isomers with cis chloridos and two N-HCl hydrogen bonds. The reaction of with PPh3 or PPh2OH affords static [RhHCl{PPh2(o-C6H4CO)}(PPh3)L] () or [RhHCl{PPh2(o-C6H4CO)}(PPh2OH)L] () respectively with trans P-atoms and pyrazoles forming N-HCl hydrogen bonds. and contain single species with hydrido cis to chlorido, while is a mixture of equal amounts of and . Complexes , with an additional O-HO hydrogen bond, selectively contain only the cis-H,Cl species with all the three ligands. The reaction of [{RhCl(COD)}2] with L and PPh2(o-C6H4CHO) (Rh : L : P = 1 : 1 : 2) led to complexes with trans P-atoms, [RhHCl{PPh2(o-C6H4CO)}{PPh2(o-C6H4CHO)-κP}L] (, and ), at room temperature, and to [RhCl{PPh2(o-C6H4CO)}{PPh2(o-C6H4CHOH)}(Hmpz)] () or [RhCl{PPh2(o-C6H4CO)}2L] () with hydrogen evolution in refluxing benzene. DFT calculations were used to predict the correct isomers, their ratios and the particular intramolecular hydrogen bonds in these complexes. Single crystal X-ray diffraction analysis was performed on , and . Complexes are efficient homogeneous catalysts (0.5 mol% loading) in the hydrolysis of amine- or ammonia-borane (AB) to generate up to 3 equivalents

  16. Concept model of the formation process of humic acid-kaolin complexes deduced by trichloroethylene sorption experiments and various characterizations.

    Science.gov (United States)

    Zhu, Xiaojing; He, Jiangtao; Su, Sihui; Zhang, Xiaoliang; Wang, Fei

    2016-05-01

    To explore the interactions between soil organic matter and minerals, humic acid (HA, as organic matter), kaolin (as a mineral component) and Ca(2+) (as metal ions) were used to prepare HA-kaolin and Ca-HA-kaolin complexes. These complexes were used in trichloroethylene (TCE) sorption experiments and various characterizations. Interactions between HA and kaolin during the formation of their complexes were confirmed by the obvious differences between the Qe (experimental sorbed TCE) and Qe_p (predicted sorbed TCE) values of all detected samples. The partition coefficient kd obtained for the different samples indicated that both the organic content (fom) and Ca(2+) could significantly impact the interactions. Based on experimental results and various characterizations, a concept model was developed. In the absence of Ca(2+), HA molecules first patched onto charged sites of kaolin surfaces, filling the pores. Subsequently, as the HA content increased and the first HA layer reached saturation, an outer layer of HA began to form, compressing the inner HA layer. As HA loading continued, the second layer reached saturation, such that an outer-third layer began to form, compressing the inner layers. In the presence of Ca(2+), which not only can promote kaolin self-aggregation but can also boost HA attachment to kaolin, HA molecules were first surrounded by kaolin. Subsequently, first and second layers formed (with inner layer compression) via the same process as described above in the absence of Ca(2+), except that the second layer continued to load rather than reach saturation, within the investigated conditions, because of enhanced HA aggregation caused by Ca(2+).

  17. Characteristic differences in the formation of complex coacervate core micelles from neodymium and zinc-based coordination polymers.

    Science.gov (United States)

    Yan, Yun; Besseling, Nicolaas A M; de Keizer, Arie; Stuart, Martien A Cohen

    2007-05-31

    In this paper we compare the formation of complex coacervate core micelles (C3Ms) from two different tricompontent mixtures, namely neodymium, the bisligand L2EO4 and the poly(cation)-block-poly(neutral) diblock copolymer P2MVP41-b-PEO205, and zinc, L2EO4 and P2MVP41-b-PEO205 mixed systems. Three sets of titration experiments were carried out for each system: (i) titration of diblock copolymer P2MVP41-b-PEO205 with the stoichiometric mixture of metal ions and bisligands, (ii) titration of a mixture of diblock copolymer and bisligand with metal ions, and (iii) titration of a mixture of diblock copolymer and metal ions with bisligands. In all the above three cases, micelles are found to form either in a broad range of charge ratios or in a broad range of metal/bisligand ratios. Upon addition of Nd2-(L2EO4)3 coordination polymer to P2MVP41-b-PEO205 solution, and upon addition of Nd3+ to a mixture of L2EO4 and P2MVP41-b-PEO205, micelles are found to form immediately after the first addition, whereas micelles show up in the similar zinc system only after a certain threshold Zn-(L2EO4) or Zn2+ concentration. This difference can be traced to the different structures of the Nd2-(L2EO4)3 and Zn-(L2EO4) coordination compounds. At very low concentrations, Zn-(L2EO4) are ring-like oligomers, but Nd2-(L2EO4)3 are larger networks. The network structure favors the formation of coacervate micellar core with P2MVP41-b-PEO205. Moreover, excess of Nd3+ ions will break up the C3Ms, while the same amount of Zn2+ has hardly any effect on the C3Ms. The breakdown of C3Ms by Nd3+ is due to the charge inversion of the coordination complex with increasing [Nd3+]/[L2EO4] ratio, which results in repulsive interaction between the coordination complex and the diblock copolymer, whereas no such interaction can occur in the zinc system.

  18. Potentiometric and spectral studies of complex formation of La(III), Pr(III) and Lu(III) with aspartic acid and asparagine

    Energy Technology Data Exchange (ETDEWEB)

    Wojciechowska, A.; Lomozik, L.; Zielinski, S.

    1987-12-01

    The composition and stability of La/sup 3 +/, Pr/sup 3 +/ and Lu/sup 3 +/ complexes with aspartic acid and asparagine were analysed. The formation of complexes of the type ML and MHL was determined for La/sup 3 +/ and Pr/sup 3 +/ with aspartic acid, and of the type MHL for Lu/sup 3 +/ with aspartic acid. For La/sup 3 +/, Pr/sup 3 +/ and Lu/sup 3 +/ with asparagine the formation of ML(OH) complexes was observed. By means of /sup 1/H NMR and /sup 13/C NMR studies the participation in the coordination of both -COOH groups was determined for aspartic acid, whereas for asparagine the participation of the -COOH group was determined in complexes with La/sup 3 +/, Pr/sup 3 +/, and of the -COOH and the -NH/sub 2/ groups in the complex with Lu/sup 3 +/.

  19. Distortion of the catalytic domain of tissue-type plasminogen activator by plasminogen activator inhibitor-1 coincides with the formation of stable serpin-proteinase complexes.

    Science.gov (United States)

    Perron, Michel J; Blouse, Grant E; Shore, Joseph D

    2003-11-28

    Plasminogen activator inhibitor-1 (PAI-1) is a typical member of the serpin family that kinetically traps its target proteinase as a covalent complex by distortion of the proteinase domain. Incorporation of the fluorescently silent 4-fluorotryptophan analog into PAI-1 permitted us to observe changes in the intrinsic tryptophan fluorescence of two-chain tissue-type plasminogen activator (tPA) and the proteinase domain of tPA during the inhibition reaction. We demonstrated three distinct conformational changes of the proteinase that occur during complex formation and distortion. A conformational change occurred during the initial formation of the non-covalent Michaelis complex followed by a large conformational change associated with the distortion of the proteinase catalytic domain that occurs concurrently with the formation of stable proteinase-inhibitor complexes. Following distortion, a very slow structural change occurs that may be involved in the stabilization or regulation of the trapped complex. Furthermore, by comparing the inhibition rates of two-chain tPA and the proteinase domain of tPA by PAI-1, we demonstrate that the accessory domains of tPA play a prominent role in the initial formation of the non-covalent Michaelis complex.

  20. Role of G protein signaling in the formation of the fibrin(ogen)-integrin αIIbβ3-actin cytoskeleton complex in platelets.

    Science.gov (United States)

    Budnik, Ivan; Shenkman, Boris; Savion, Naphtali

    2016-09-01

    Effective platelet function requires formation of a physical link between fibrin(ogen), integrin αIIbβ3, and cytoplasmic actin filaments. We investigated the role of the Gαq, Gαi, and Gα12/13 families of heterotrimeric GTP-binding proteins (G proteins) in the assembly of a ligand-αIIbβ3-actin cytoskeleton complex. Selective and combined activation of the G proteins was achieved by using combinations of various platelet agonists and inhibitors. Formation and stability of fibrinogen-αIIbβ3 interaction were evaluated by the extent of platelet aggregation and the rate of eptifibatide-induced platelet disaggregation; association of αIIbβ3 with the cytoskeleton was analyzed by western blot. Formation of the fibrin-αIIbβ3-actin cytoskeleton complex was evaluated by rotational thromboelastometry assay in which clot formation was induced by the mixture of reptilase and factor XIIIa. We demonstrated that involvement of heterotrimeric G proteins in the formation of the ligand-αIIbβ3-cytoskeleton complex depends on whether fibrinogen or fibrin serves as the integrin ligand. Formation of the fibrinogen-αIIbβ3-cytoskeleton complex requires combined activation of at least two G protein pathways while the maximal αIIbβ3-cytoskeleton association and the strongest αIIbβ3-fibrinogen binding supporting irreversible platelet aggregation require combined activation of all three-Gαq, Gαi, and Gα12/13-G protein families. In contrast, formation of the fibrin-αIIbβ3-cytoskeleton complex mediating clot retraction is critically dependent on the activation of the Gαi family, especially on the activation of Gαz.

  1. Formation of complexes between hematite nanoparticles and a non-conventional galactomannan gum. Toward a better understanding on interaction processes.

    Science.gov (United States)

    Busch, Verónica M; Loosli, Fréderic; Santagapita, Patricio R; Buera, M Pilar; Stoll, Serge

    2015-11-01

    The physicochemical characteristics of hematite nanoparticles related to their size, surface area and reactivity make them useful for many applications, as well as suitable models to study aggregation kinetics. For several applications (such as remediation of contaminated groundwater) it is crucial to maintain the stability of hematite nanoparticle suspensions in order to assure their arrival to the target place. The use of biopolymers has been proposed as a suitable environmentally friendly option to avoid nanoparticle aggregation and assure their stability. The aim of the present work was to investigate the formation of complexes between hematite nanoparticles and a non-conventional galactomannan (vinal gum--VG) obtained from Prosopis ruscifolia in order to promote hematite nanoparticle coating with a green biopolymer. Zeta potential and size of hematite nanoparticles, VG dispersions and the stability of their mixtures were investigated, as well as the influence of the biopolymer concentration and preparation method. DLS and nanoparticle tracking analysis techniques were used for determining the size and the zeta-potential of the suspensions. VG showed a polydispersed size distribution (300-475 nm Z-average diameter, 0.65 Pdi) and a negative zeta potential (between -1 and -12 mV for pH2 and 12, respectively). The aggregation of hematite nanoparticles (3.3 mg/L) was induced by the addition of VG at lower concentrations than 2mg/L (pH5.5). On the other hand, hematite nanoparticles were stabilized at concentrations of VG higher than 2 mg/L. Several phenomena between hematite nanoparticles and VG were involved: steric effects, electrostatic interactions, charge neutralization, charge inversion and polymer bridging. The process of complexation between hematite nanoparticles and the biopolymer was strongly influenced by the preparation protocols. It was concluded that the aggregation, dispersion, and stability of hematite nanoparticles depended on biopolymer

  2. Characterisation of sub-micron particle number concentrations and formation events in the western Bushveld Igneous Complex, South Africa

    Directory of Open Access Journals (Sweden)

    A. Hirsikko

    2012-05-01

    Full Text Available South Africa holds significant mineral resources, with a substantial fraction of these reserves occurring and being processed in a large geological structure termed the Bushveld Igneous Complex (BIC. The area is also highly populated by informal, semi-formal and formal residential developments. However, knowledge of air quality and research related to the atmosphere is still very limited in the area. In order to investigate the characteristics and processes affecting sub-micron particle number concentrations and formation events, air ion and aerosol particle size distributions and number concentrations, together with meteorological parameters, trace gases and particulate matter (PM were measured for over two years at Marikana in the heart of the western BIC. The observations showed that trace gas (i.e. SO2, NOx, CO and black carbon concentrations were relatively high, but in general within the limits of local air quality standards. The area was characterised by very high condensation sink due to background aerosol particles, PM10 and O3 concentration. The results indicated that high amounts of Aitken and accumulation mode particles originated from domestic burning for heating and cooking in the morning and evening, while during daytime SO2-based nucleation followed by the growth by condensation of vapours from industrial, residential and natural sources was the most probable source for large number concentrations of nucleation and Aitken mode particles. Nucleation event day frequency was extremely high, i.e. 86% of the analysed days, which to the knowledge of the authors is the highest frequency ever reported. The air mass back trajectory and wind direction analyses showed that the secondary particle formation was influenced both by local and regional pollution and vapour sources. Therefore, our observation of the annual cycle and magnitude of the particle formation and growth rates during

  3. Thermodynamics of the formation of complexes of copper(II) ions and glycylglycine in aqueous solutions at 298 K according to calorimetry data

    Science.gov (United States)

    Kochergina, L. A.; Emel'yanov, A. V.

    2015-04-01

    Heat effects of the interaction between glycylglycine and copper(II) nitrate solutions are measured by direct calorimetry at a [metal] : [ligand] ratio of 1 : 5 and at different pH values of the solution. The measurements are made at a temperature of 298.15 K and ionic strengths of 0.25, 0.50, and 0.75. KNO3 is used as a background electrolyte. The thermodynamic characteristics of complex formation by the peptide and copper(II) ions in aqueous solutions are determined. Standard enthalpies of the formation of complex particles in aqueous solutions are calculated.

  4. Implantable biodegradable sponges: effect of interpolymer complex formation of chitosan with gelatin on the release behavior of tramadol hydrochloride.

    Science.gov (United States)

    Foda, Nagwa H; El-laithy, Hanan M; Tadros, Mina I

    2007-01-01

    The effect of interpolymer complex formation between positively charged chitosan and negatively charged gelatin (Type B) on the release behavior of tramadol hydrochloride from biodegradable chitosan-gelatin sponges was studied. Mixed sponges were prepared by freeze-drying the cross-linked homogenous stable foams produced from chitosan and gelatin solutions where gelatin acts as a foam builder. Generation of stable foams was optimized where concentration, pH of gelatin solution, temperature, speed and duration of whipping process, and, chitosan-gelatin ratio drastically affect the properties and the stability of the produced foams. The prepared sponges were evaluated for their morphology, drug content, and microstructure using scanning electron microscopy, mechanical properties, uptake capacity, drug release profile, and their pharmacodynamic activity in terms of the analgesic effect after implantation in Wistar rats. It was revealed that whipping 7% (w/w) gelatin solution, of pH 5.5, for 15 min at 25 degrees C with a stirring speed of 1000 rpm was the optimum conditions for stable gelatin foam generation. Moreover, homogenous, uniform chitosan-gelatin foam with small air bubbles were produced by mixing 2.5% w/w chitosan solution with 7% w/w gelatin solution in 1:5 ratio. Indeed, polyionic complexation between chitosan and gelatin overcame the drawbacks of chitosan sponge mechanical properties where, pliable, soft, and compressible sponge with high fluid uptake capacity was produced at 25 degrees C and 65% relative humidity without any added plasticizer. Drug release studies showed a successful retardation of the incorporated drug where the t50% values of the dissolution profiles were 0.55, 3.03, and 4.73 hr for cross-linked gelatin, un-cross-linked chitosan-gelatin, and cross-linked chitosan-gelatin sponges, respectively. All the release experiments followed Higuchi's diffusion mechanism over 12 hr. The achieved drug prolongation was a result of a combined effect

  5. Spitzer Analysis of HII Region Complexes in the Magellanic Clouds: Determining a Suitable Monochromatic Obscured Star Formation Indicator

    CERN Document Server

    Lawton, Brandon; Babler, Brian; Block, Miwa; Bolatto, Alberto D; Bracker, Steve; Carlson, Lynn R; Engelbracht, Charles W; Hora, Joseph L; Indebetouw, Remy; Madden, Suzanne C; Meade, Marilyn; Meixner, Margaret; Misselt, Karl; Oey, M S; Oliveira, Joana M; Robitaille, Thomas; Sewilo, Marta; Shiao, Bernie; Vijh, Uma P; Whitney, Barbara

    2010-01-01

    HII regions are the birth places of stars, and as such they provide the best measure of current star formation rates (SFRs) in galaxies. The close proximity of the Magellanic Clouds allows us to probe the nature of these star forming regions at small spatial scales. We aim to determine the monochromatic IR band that most accurately traces the bolometric IR flux (TIR), which can then be used to estimate an obscured SFR. We present the spatial analysis, via aperture/annulus photometry, of 16 LMC and 16 SMC HII region complexes using the Spitzer IRAC and MIPS bands. UV rocket data and SHASSA H-alpha data are also included. We find that nearly all of the LMC and SMC HII region SEDs peak around 70um, from ~10 to ~400 pc from the central sources. As a result, the sizes of HII regions as probed by 70um is approximately equal to the sizes as probed by TIR (about 70 pc in radius); the radial profile of the 70um flux, normalized by TIR, is constant at all radii (70um ~ 0.45 TIR); the 1-sigma standard deviation of the 7...

  6. SMU.746-SMU.747, a putative membrane permease complex, is involved in aciduricity, acidogenesis, and biofilm formation in Streptococcus mutans.

    Science.gov (United States)

    Król, Jaroslaw E; Biswas, Saswati; King, Clay; Biswas, Indranil

    2014-01-01

    Dental caries induced by Streptococcus mutans is one of the most prevalent chronic infectious diseases worldwide. The pathogenicity of S. mutans relies on the bacterium's ability to colonize tooth surfaces and survive a strongly acidic environment. We performed an ISS1 transposon mutagenesis to screen for acid-sensitive mutants of S. mutans and identified an SMU.746-SMU.747 gene cluster that is needed for aciduricity. SMU.746 and SMU.747 appear to be organized in an operon and encode a putative membrane-associated permease. SMU.746- and SMU.747-deficient mutants showed a reduced ability to grow in acidified medium. However, the short-term or long-term acid survival capacity and F1F0 ATPase activity remained unaffected in the mutants. Furthermore, deletion of both genes did not change cell membrane permeability and the oxidative and heat stress responses. Growth was severely affected even with slight acidification of the defined medium (pH 6.5). The ability of the mutant strain to acidify the defined medium during growth in the presence of glucose and sucrose was significantly reduced, although the glycolysis rate was only slightly affected. Surprisingly, deletion of the SMU.746-SMU.747 genes triggered increased biofilm formation in low-pH medium. The observed effects were more striking in a chemically defined medium. We speculate that the SMU.746-SMU.747 complex is responsible for amino acid transport, and we discuss its possible role in colonization and survival in the oral environment.

  7. Nanoscale UO{sub 2} and novel complex U(IV)-sulphate phase formation from electrolytically reduced uranyl sulphate solutions

    Energy Technology Data Exchange (ETDEWEB)

    Gil, D.; Malmbeck, R.; Spino, J.; Fanghaenel, T. [European Commission, Joint Research Centre, Inst. for Transuranium Elements, Karlsruhe (Germany); Dinnebier, R. [Max Planck Inst. for Solid State Research, Stuttgart (Germany)

    2010-07-01

    Three different processes have been explored to determine the ranges of U-concentration and acidity (pH-value) for nanocrystalline U{sub 2+x} precipitation from electrolytically reduced uranyl sulphate solutions. Precipitation of U{sub 2+x} nanoparticles aggregates was found to occur only in the narrow range of pH {proportional_to} 4.5 to 5 and for U-concentrations of {proportional_to} 10{sup -6} to 10{sup -7} M. The solid phase crystallized with the typical UO{sub 2}-fcc structure and with a crystallite size {<=} 3 nm. The average aggregate size was mostly {<=} 80 nm. At higher U-concentrations, ranging from [U] {proportional_to} 10{sup -1} M at pH {proportional_to} 1.5 to [U] {proportional_to} 5 x 10{sup -4} M at pH {proportional_to} 4.9, formation of microscale precipitates of a novel complex U(IV)-sulphate phase occurred, which was characterized by SEM/EDX-WDX, ICP-OES and XRD-powder diffraction. The crystal structure was identified with an orthorhombic cell (space group Cmca), with the following lattice parameters: a = 1.974(0)(2) nm, b = 1.3336(2) nm and c = 2.0643(2) nm. Further composition analyses indicated a basic sulphate hydrate of the type Na{sub 3}U(SO{sub 4}){sub 3}(OH).nH{sub 2}O. (orig.)

  8. Influence of Exciplex formation on the electroluminescent properties of dimeric Zn (II) bis-2-(2'-hydroxyphenyl) benzoxazole complex and monomeric Zn (II) 2-(1'-hydroxynaphthyl) benzothiazole complex

    Science.gov (United States)

    Prakash, Sattey; Anand, R. S.; Manoharan, S. Sundar

    2011-10-01

    In this paper we present the factors affecting electroluminescent properties of Zinc complexes of oxazole & thiazole derivatives. Electroluminescent spectra of the Zinc (II) complex of bis-[2-(2'-hydroxyphenyl) benzoxazole], [Zn (HPBO)2]2 and 2-(1'-hydroxynaphthyl) benzothiazole [Zn (HNBT)2] show unusual broadening and shows structural and photophysical similarity with [Zn (HPBT)2]2, a dimeric complex. The [Zn (HPBO)2]2 complex as an emissive layer in the device structure ITO /PEDOT:PSS /TPD (30nm) /[Zn (HPBO)2]2 (60nm) /BCP (6nm) /Ca (3nm) /Al (200nm) shows a broad bluish green emission, with a full width at half maxima (FWHM1˜70nm). The EL spectra is much broader compared to the PL spectra because of exciplex formation at the interfacial region between the emissive layer (EML) & hole transport layer (HTL). We also show the device performance of Zinc 2-(1'-hydroxynaphthyl) benzothiazole [Zn (HNBT)2] complex as emissive layer. Distinctly this device shows a broad greenish yellow emission with a peak maxima at 535nm and 690nm, owing to the exciplex formation between electron transport layer (ETL) and emissive layer (EML), which is in sharp contrast to the exciplex formation across the HTL-EML interface observed for the [Zn (HPBO)2]2 complex.

  9. Chemical physics behind formation of efficient charge-separated state for complexation between PC70BM and designed diporphyrin in solution.

    Science.gov (United States)

    Ray, Anamika; Banerjee, Shrabanti; Ghosh, Shalini; Bauri, Ajoy K; Bhattacharya, Sumanta

    2016-01-05

    The present work reports supramolecular interaction of [6,6]-phenyl C71 butyric acid methyl ester (PC70BM) with two designed diporphyrin molecules having dithiophene (1) and carbazole (2) spacer in solvent having varying polarity. Studies on complex formation reveal relatively higher binding constant for PC70BM/2 complex in all the solvent studied. Solvent dependence of charge separation and charge recombination processes in PC70BM/diporphyrin non-covalent complexes has been well established in present work. Donor-acceptor geometry and stabilization of the singlet excited state of the diporphyrin during charge recombination are considered to be the possible reasons for this behavior.

  10. Determination of combustion energies and the standard enthalpies of formation for the complexes of RE(Et2dtc)3(phen)

    Institute of Scientific and Technical Information of China (English)

    YANG Xuwu; ZHU Li; CHEN Sanping; GAO Shengli; SHI Qizhen

    2005-01-01

    Solid complexes, RE(Et2dtc)3(phen) (RE=La, Pr, Nd, Sm-Lu), were synthesized hydrated lanthanide chlorides in absolute ethanol. The constant-volume combustion energies of complexes, △cU, were determined by a precise rotating-bomb calorimeter at 298.15 K. The standard enthalpies of combustion, AcHmθ, and standard enthalpies of formation, AfHmθ, were calculated for these complexes, respectively. The experiment results showed the "tripartite effect"of rare earth.

  11. Formation of ternary complexes between a macrotricyclic host and hetero-guest pairs: an acid-base controlled selective complexation process.

    Science.gov (United States)

    Han, Tao; Chen, Chuan-Feng

    2007-10-11

    A triptycene-based cylindrical macrotricyclic host can include diquat and electron-rich aromatics simultaneously to form stable ternary complexes, which is stabilized not only by a charge-transfer (CT) interaction between electron-rich and electron-deficient guests but also by the face to face pi-stacking interactions between the host and the guests. Moreover, a selective complexation process between a ternary complex containing benzidine and a binary complex can be effectively controlled by the use of acid and base.

  12. TGF-{beta} signals the formation of a unique NF1/Smad4-dependent transcription repressor-complex in human diploid fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Luciakova, Katarina, E-mail: katarina.luciakova@savba.sk [Cancer Research Institute, Slovak Academy of Sciences, Bratislava, Vlarska 7, 833 91 Bratislava (Slovakia); Kollarovic, Gabriel; Kretova, Miroslava; Sabova, Ludmila [Cancer Research Institute, Slovak Academy of Sciences, Bratislava, Vlarska 7, 833 91 Bratislava (Slovakia); Nelson, B. Dean [Department of Biochemistry and Biophysics, Arrhenius Laboratories, Stockholm University, S-106 91 Stockholm (Sweden)

    2011-08-05

    Highlights: {yields} TGF-{beta} induces the formation of unique nuclear NF1/Smad4 complexes that repress expression of the ANT-2 gene. {yields} Repression is mediated through an NF1-dependent repressor element in the promoter. {yields} The formation of NF1/Smad4 complexes and the repression of ANT2 are prevented by inhibitors of p38 kinase and TGF-{beta} RI. {yields} NF1/Smad complexes implicate novel role for NF1 and Smad proteins in the regulation of growth. -- Abstract: We earlier reported the formation of a unique nuclear NF1/Smad complex in serum-restricted fibroblasts that acts as an NF1-dependent repressor of the human adenine nucleotide translocase-2 gene (ANT2) [K. Luciakova, G. Kollarovic, P. Barath, B.D. Nelson, Growth-dependent repression of human adenine nucleotide translocator-2 (ANT2) transcription: evidence for the participation of Smad and Sp family proteins in the NF1-dependent repressor complex, Biochem. J. 412 (2008) 123-130]. In the present study, we show that TGF-{beta}, like serum-restriction: (a) induces the formation of NF1/Smad repressor complexes, (b) increases binding of the complexes to the repressor elements (Go elements) in the ANT2 promoter, and (c) inhibits ANT2 expression. Repression of ANT2 by TGF-{beta} is eliminated by mutating the NF1 binding sites in the Go repressor elements. All of the above responses to TGF-{beta} are prevented by inhibitors of TGF-{beta} RI and MAPK p38. These inhibitors also prevent NF1/Smad4 repressor complex formation and repression of ANT2 expression in serum-restricted cells, suggesting that similar signaling pathways are initiated by TGF-{beta} and serum-restriction. The present finding that NF1/Smad4 repressor complexes are formed through TGF-{beta} signaling pathways suggests a new, but much broader, role for these complexes in the initiation or maintenance of the growth-inhibited state.

  13. Spectrophotometric Determination of 6-Propyl-2-Thiouracil in Pharmaceutical Formulations Based on Prussian Blue Complex Formation: An Undergraduate Instrumental Analysis Laboratory Experiment

    Science.gov (United States)

    Zakrzewski, Robert; Skowron, Monika; Ciesielski, Witold; Rembisz, Zaneta

    2016-01-01

    The laboratory experiment challenges students to determine 6-propyl-2-thiouracil (PTU) based on Prussian blue complex formation. Prussian blue is formed by ferricyanide and Fe(II) ions which are generated in situ from Fe(III) ions reduced by PTU. The absorbance of this product was measured at a wavelength of 840 nm, after a reaction time of 30…

  14. Influence of the overall charge and local charge density of pectin on the complex formation between pectin and beta-lactoglobulin

    NARCIS (Netherlands)

    Sperber, Bram L. H. M.; Schols, Henk A.; Stuart, Martien A. Cohen; Norde, Willem; Voragen, Alphons G. J.

    2009-01-01

    The complex formation between beta-lactoglobulin (beta-lg) and pectin is studied using pectins with different physicochemical characteristics. Pectin allows for the control of both the overall charge by degree of methyl-esterification as well as local charge density by the degree of blockiness. Vary

  15. Theoretical studies on N-O or N-N bond formation from aryl azide catalyzed by iron(II) bromide complex.

    Science.gov (United States)

    Li, Juan; Zhang, Qi; Zhou, Lixin

    2012-03-02

    DFT calculations have been carried out to study the reaction mechanism on N-O or N-N bond formation from aryl azide catalyzed by iron(II) bromide complex. A favorable reaction pathway is proposed to account for the construction of the core structure of 2H-indazoles or 2,1-benzisoxazoles.

  16. Self-templated formation of uniform NiCo2O4 hollow spheres with complex interior structures for lithium-ion batteries and supercapacitors.

    Science.gov (United States)

    Shen, Laifa; Yu, Le; Yu, Xin-Yao; Zhang, Xiaogang; Lou, Xiong Wen David

    2015-02-02

    Despite the significant advancement in preparing metal oxide hollow structures, most approaches rely on template-based multistep procedures for tailoring the interior structure. In this work, we develop a new generally applicable strategy toward the synthesis of mixed-metal-oxide complex hollow spheres. Starting with metal glycerate solid spheres, we show that subsequent thermal annealing in air leads to the formation of complex hollow spheres of the resulting metal oxide. We demonstrate the concept by synthesizing highly uniform NiCo2O4 hollow spheres with a complex interior structure. With the small primary building nanoparticles, high structural integrity, complex interior architectures, and enlarged surface area, these unique NiCo2O4 hollow spheres exhibit superior electrochemical performances as advanced electrode materials for both lithium-ion batteries and supercapacitors. This approach can be an efficient self-templated strategy for the preparation of mixed-metal-oxide hollow spheres with complex interior structures and functionalities.

  17. Non-covalent interactions of nitrous oxide with aromatic compounds: Spectroscopic and computational evidence for the formation of 1:1 complexes

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Qian [Department of Chemistry, P.O. Box 55, University of Helsinki, Helsinki FI-00014 (Finland); School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275 (China); Gor, Gennady Y., E-mail: ggor@princeton.edu [Department of Civil and Environmental Engineering, Princeton University, Princeton, New Jersey 08544 (United States); Krogh-Jespersen, Karsten [Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08903 (United States); Khriachtchev, Leonid [Department of Chemistry, P.O. Box 55, University of Helsinki, Helsinki FI-00014 (Finland)

    2014-04-14

    We present the first study of intermolecular interactions between nitrous oxide (N{sub 2}O) and three representative aromatic compounds (ACs): phenol, cresol, and toluene. The infrared spectroscopic experiments were performed in a Ne matrix and were supported by high-level quantum chemical calculations. Comparisons of the calculated and experimental vibrational spectra provide direct identification and characterization of the 1:1 N{sub 2}O-AC complexes. Our results show that N{sub 2}O is capable of forming non-covalently bonded complexes with ACs. Complex formation is dominated by dispersion forces, and the interaction energies are relatively low (about −3 kcal mol{sup −1}); however, the complexes are clearly detected by frequency shifts of the characteristic bands. These results suggest that N{sub 2}O can be bound to the amino-acid residues tyrosine or phenylalanine in the form of π complexes.

  18. Non-covalent interactions of nitrous oxide with aromatic compounds: Spectroscopic and computational evidence for the formation of 1:1 complexes

    Science.gov (United States)

    Cao, Qian; Gor, Gennady Y.; Krogh-Jespersen, Karsten; Khriachtchev, Leonid

    2014-04-01

    We present the first study of intermolecular interactions between nitrous oxide (N2O) and three representative aromatic compounds (ACs): phenol, cresol, and toluene. The infrared spectroscopic experiments were performed in a Ne matrix and were supported by high-level quantum chemical calculations. Comparisons of the calculated and experimental vibrational spectra provide direct identification and characterization of the 1:1 N2O-AC complexes. Our results show that N2O is capable of forming non-covalently bonded complexes with ACs. Complex formation is dominated by dispersion forces, and the interaction energies are relatively low (about -3 kcal mol-1); however, the complexes are clearly detected by frequency shifts of the characteristic bands. These results suggest that N2O can be bound to the amino-acid residues tyrosine or phenylalanine in the form of π complexes.

  19. COX7A2L Is a Mitochondrial Complex III Binding Protein that Stabilizes the III2+IV Supercomplex without Affecting Respirasome Formation.

    Science.gov (United States)

    Pérez-Pérez, Rafael; Lobo-Jarne, Teresa; Milenkovic, Dusanka; Mourier, Arnaud; Bratic, Ana; García-Bartolomé, Alberto; Fernández-Vizarra, Erika; Cadenas, Susana; Delmiro, Aitor; García-Consuegra, Inés; Arenas, Joaquín; Martín, Miguel A; Larsson, Nils-Göran; Ugalde, Cristina

    2016-08-30

    Mitochondrial respiratory chain (MRC) complexes I, III, and IV associate into a variety of supramolecular structures known as supercomplexes and respirasomes. While COX7A2L was originally described as a supercomplex-specific factor responsible for the dynamic association of complex IV into these structures to adapt MRC function to metabolic variations, this role has been disputed. Here, we further examine the functional significance of COX7A2L in the structural organization of the mammalian respiratory chain. As in the mouse, human COX7A2L binds primarily to free mitochondrial complex III and, to a minor extent, to complex IV to specifically promote the stabilization of the III2+IV supercomplex without affecting respirasome formation. Furthermore, COX7A2L does not affect the biogenesis, stabilization, and function of the individual oxidative phosphorylation complexes. These data show that independent regulatory mechanisms for the biogenesis and turnover of different MRC supercomplex structures co-exist.

  20. Energetic Mechanism of Cytochrome c-Cytochrome c Oxidase Electron Transfer Complex Formation under Turnover Conditions Revealed by Mutational Effects and Docking Simulation.

    Science.gov (United States)

    Sato, Wataru; Hitaoka, Seiji; Inoue, Kaoru; Imai, Mizue; Saio, Tomohide; Uchida, Takeshi; Shinzawa-Itoh, Kyoko; Yoshikawa, Shinya; Yoshizawa, Kazunari; Ishimori, Koichiro

    2016-07-15

    Based on the mutational effects on the steady-state kinetics of the electron transfer reaction and our NMR analysis of the interaction site (Sakamoto, K., Kamiya, M., Imai, M., Shinzawa-Itoh, K., Uchida, T., Kawano, K., Yoshikawa, S., and Ishimori, K. (2011) Proc. Natl. Acad. Sci. U.S.A. 108, 12271-12276), we determined the structure of the electron transfer complex between cytochrome c (Cyt c) and cytochrome c oxidase (CcO) under turnover conditions and energetically characterized the interactions essential for complex formation. The complex structures predicted by the protein docking simulation were computationally selected and validated by the experimental kinetic data for mutant Cyt c in the electron transfer reaction to CcO. The interaction analysis using the selected Cyt c-CcO complex structure revealed the electrostatic and hydrophobic contributions of each amino acid residue to the free energy required for complex formation. Several charged residues showed large unfavorable (desolvation) electrostatic interactions that were almost cancelled out by large favorable (Columbic) electrostatic interactions but resulted in the destabilization of the complex. The residual destabilizing free energy is compensated by the van der Waals interactions mediated by hydrophobic amino acid residues to give the stabilized complex. Thus, hydrophobic interactions are the primary factors that promote complex formation between Cyt c and CcO under turnover conditions, whereas the change in the electrostatic destabilization free energy provides the variance of the binding free energy in the mutants. The distribution of favorable and unfavorable electrostatic interactions in the interaction site determines the orientation of the binding of Cyt c on CcO.

  1. Remarkable fluorescence enhancement versus complex formation of cationic porphyrins on the surface of ZnO nanoparticles

    KAUST Repository

    Aly, Shawkat Mohammede

    2014-06-12

    Fluorescence enhancement of organic fluorophores shows tremendous potential to improve image contrast in fluorescence-based bioimaging. Here, we present an experimental study of the interaction of two cationic porphyrins, meso-tetrakis(1-methylpyridinium-4-yl)porphyrin chloride (TMPyP) and meso-tetrakis(4-N,N,N-trimethylanilinium)porphyrin chloride (TMAP), with cationic surfactant-stabilized zinc oxide nanoparticles (ZnO NPs) based on several steady-state and time-resolved techniques. We show the first experimental measurements demonstrating a clear transition from pronounced fluorescence enhancement to charge transfer (CT) complex formation by simply changing the nature and location of the positive charge of the meso substituent of the cationic porphyrins. For TMPyP, we observe a sixfold increase in the fluorescence intensity of TMPyP upon addition of ZnO NPs. Our experimental results indicate that the electrostatic binding of TMPyP with the surface of ZnO NPs increases the symmetry of the porphyrin macrocycle. This electronic communication hinders the rotational relaxation of the meso unit and/or decreases the intramolecular CT character between the cavity and the meso substituent of the porphyrin, resulting in the enhancement of the intensity of the fluorescence. For TMAP, on the other hand, the different type and nature of the positive charge resulting in the development of the CT band arise from the interaction with the surface of ZnO NPs. This observation is confirmed by the femtosecond transient absorption spectroscopy, which provides clear spectroscopic signatures of photoinduced electron transfer from TMAP to ZnO NPs. © 2014 American Chemical Society.

  2. Continental rifting and metamorphic core complex formation ahead of the Woodlark spreading ridge, D'Entrecasteaux Islands, Papua New Guinea

    Science.gov (United States)

    Little, Timothy A.; Baldwin, S. L.; Fitzgerald, P. G.; Monteleone, B.

    2007-02-01

    We evaluate the role of a metamorphic core complex (MCC) on Normanby Island in the Woodlark rift. Located 1 km thickness of blueschist-derived mylonites formed in a midcrustal shear zone during the Pliocene at ˜400-500°C. This top-to-the-north zone appears to have reactivated the gently dipping base of the Papuan ophiolite (Papuan Ultramafic Body, PUB), and its continued activity appears to control the north dipping asymmetry of active half grabens to the north of the MCC and rapid subsidence of the Woodlark Rise. Mylonites in the MCC's lower plate have been exhumed along a detachment as a result of >50 km of slip at rates of >12 mm/yr. The inactive, back-tilted detachment preserves fault surface megamullions and mylonitic lineations parallel to the Plio-Pleistocene plate motion. A second SE vergent detachment has been established on the opposite flank of this rolling-hinge style MCC, probably since 0.8) at depth, and provide a sufficient mechanism for activating low-angle normal faults in the rift. MCC inception was not localized to the tip of the Woodlark MOR. Instead, extreme crustal thinning near the MCC preconditioned later continental breakup. The lower crust appears to be weak, thickening beneath unloaded footwalls to uplift MCCs above sea level, and flowing laterally to even out regional crustal thickness contrasts on a 1-6 m.y. timescale. Deep-seated transforms separate rheologically distinct domains in which extension has been localized along the weak PUB to cause MCC formation, vs. those in which slip is distributed across an imbricate zone of more uniform strength normal faults. The Trobriand fault connects in the eastern Woodlark rift to the Owen Stanley fault in the Papuan Ranges, which is probably moving at nearly the full plate velocity.

  3. Discrimination between platelet-mediated and coagulation-mediated mechanisms in a model of complex thrombus formation in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Cadroy, Y.; Horbett, T.A.; Hanson, S.R.

    1989-04-01

    To study mechanisms of complex thrombus formation in vivo, and to compare the relative antithrombotic effects of anticoagulants and antiplatelet agents, a model was developed in baboons. Segments of collagen-coated tubing followed by two sequentially placed expansion chambers exhibiting disturbed flow patterns were exposed to native blood under laminar flow conditions. The device was incorporated for 1 hour into an exteriorized arteriovenous shunt in baboons under controlled blood flow (20 ml/min). Morphologic evaluation by scanning electron microscopy showed that thrombi associated with collagen were relatively rich in platelets but thrombi in the chambers were rich in fibrin and red cells. Deposition of indium 111-labeled platelets was continuously measured with a scintillation camera. Platelet deposition increased in a linear (collagen-coated segment) or exponential (chambers 1 and 2) fashion over time, with values after 40 minutes averaging 24.1 +/- 3.3 x 10(8) platelets (collagen segment), 16.7 +/- 3.4 x 10(8) platelets (chamber 1), and 8.4 +/- 2.4 x 10(8) platelets (chamber 2). Total fibrinogen deposition after 40 minutes was determined by using iodine 125-labeled baboon fibrinogen and averaged 0.58 +/- 0.14 mg in the collagen segment, 1.51 +/- 0.27 mg in chamber 1, and 0.95 +/- 0.25 mg in chamber 2. Plasma levels of beta-thromboglobulin (beta TG), platelet-factor 4 (PF4), and fibrinopeptide A (FPA) increased fourfold to fivefold after 60 minutes of blood exposure to the thrombotic device. Platelet deposition onto the collagen segment, chamber 1, and chamber 2 was linearly dependent on the circulating platelet count. Platelet accumulation in chamber 1 and chamber 2 was also dependent on the presence of the proximal collagen segment.

  4. A common intermediate for N2 formation in enzymes and zeolites: side-on Cu-nitrosyl complexes

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Ja Hun; Lee, Jong H.; Burton, Sarah D.; Lipton, Andrew S.; Peden, Charles HF; Szanyi, Janos

    2013-09-16

    Understanding the mechanisms of catalytic processes requires the identification of reaction centers and key intermediates, both of which are often achieved by the use of spectroscopic characterization tools. Due to the heterogeneity of active centers in heterogeneous catalysts, it is frequently difficult to identify the specific sites that are responsible for the overall activity. Furthermore, the simultaneous presence of a large number of surface species on the catalyst surface often poses a great challenge for the unambiguous determination of the relevant species in the reaction mechanism. In contrast, enzymes possess catalytically active centers with precisely defined coordination environments that are only able to accommodate intermediates relevant to the specific catalytic process. Here we show that side-on Cu+-NO+ complexes characterized by high magnetic field solid state magic angle spinning nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopies are the key intermediates in the selective catalytic reduction of NO over Cu-SSZ-13 zeolite catalysts. Analogous intermediates have been observed and characterized in nitrite reductase enzymes, and shown to be the critical intermediates in the formation of N2 for anaerobic ammonium oxidation reactions.[1] The identification of this key reaction intermediate, combined with the results of our prior kinetic studies, allows us to propose a new reaction mechanism for the selective catalytic reduction of NO with NH3 under oxygen-rich environments over Cu-SSZ-13 zeolites, a key reaction in automotive emission control. The authors acknowledge the US Department of Energy (DOE), Office of Energy Efficiency and Renewable Energy/Vehicle Technologies Program for the support of this work. The research described in this paper was performed at the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the DOE’s Office of Biological and Environmental

  5. Establishment of an in silico phospholipidosis prediction method using descriptors related to molecular interactions causing phospholipid-compound complex formation.

    Science.gov (United States)

    Haranosono, Yu; Nemoto, Shingo; Kurata, Masaaki; Sakaki, Hideyuki

    2016-04-01

    Although phospholipidosis (PLD) often affects drug development, there is no convenient in vitro or in vivo test system for PLD detection. In this study, we developed an in silico PLD prediction method based on the PLD-inducing mechanism. We focused on phospholipid (PL)-compound complex formation, which inhibits PL degradation by phospholipase. Thus, we used some molecular interactions, such as electrostatic interactions, hydrophobic interactions, and intermolecular forces, between PL and compounds as descriptors. First, we performed descriptor screening for intermolecular force and then developed a new in silico PLD prediction using descriptors related to molecular interactions. Based on the screening, we identified molecular refraction (MR) as a descriptor of intermolecular force. It is known that ClogP and most-basic pKa can be used for PLD prediction. Thereby, we developed an in silico prediction method using ClogP, most-basic pKa, and MR, which were related to hydrophobic interactions, electrostatic interactions, and intermolecular forces. In addition, a resampling method was used to determine the cut-off values for each descriptor. We obtained good results for 77 compounds as follows: sensitivity = 95.8%, specificity = 75.9%, and concordance = 88.3%. Although there is a concern regarding false-negative compounds for pKa calculations, this predictive ability will be adequate for PLD screening. In conclusion, the mechanism-based in silico PLD prediction method provided good prediction ability, and this method will be useful for evaluating the potential of drugs to cause PLD, particularly in the early stage of drug development, because this method only requires knowledge of the chemical structure.

  6. Study of complex formation between C18H36N2O6 and UO22+ cation in some binary mixed non-aqueous solutions

    Directory of Open Access Journals (Sweden)

    G.H. Rounaghi

    2017-02-01

    Full Text Available The complexation reaction between UO22+ cation and the macrobicyclic ligand C18H36N2O6 was studied in acetonitrile–dimethylformamide (AN–DMF, acetonitrile–tetrahydrofuran (AN–THF, acetonitrile–dichloromethane (AN–DCM binary solvent solutions at different temperatures using the coductometric method. In most cases, C18H36N2O6 forms a 1:1 [M:L] complex with the UO22+ cation. But in some of the studied solvent systems, in addition to formation of a 1:1 complex, a 1:2 [M:L2] complex is formed in solution. A non-linear behavior was observed for changes of logKf of the (C18H36N2O6·UO22+ complex versus the composition of the binary mixed solvents. The sequence of the stability of the (C18H36N2O6·UO22+ complex in pure solvent systems at 25 °C decreases in the order: AN > THF > DMF. In the case of binary solvent solutions, the stability constant of the complex at 25 °C was found to be: AN–DCM > AN–THF > AN–DMF. The values of thermodynamic quantities (ΔSc°,ΔHc°, for the formation of the complex were obtained from temperature dependence of the stability constant of the complex using the van't Hoff plots. The results show that in all cases, the complex is both entropy and enthalpy stabilized and both of these parameters are affected by the nature and composition of the mixed solvent systems.

  7. Proteomic analysis of HIV-1 Nef cellular binding partners reveals a role for exocyst complex proteins in mediating enhancement of intercellular nanotube formation

    Directory of Open Access Journals (Sweden)

    Mukerji Joya

    2012-06-01

    Full Text Available Abstract Background HIV-1 Nef protein contributes to pathogenesis via multiple functions that include enhancement of viral replication and infectivity, alteration of intracellular trafficking, and modulation of cellular signaling pathways. Nef stimulates formation of tunneling nanotubes and virological synapses, and is transferred to bystander cells via these intercellular contacts and secreted microvesicles. Nef associates with and activates Pak2, a kinase that regulates T-cell signaling and actin cytoskeleton dynamics, but how Nef promotes nanotube formation is unknown. Results To identify Nef binding partners involved in Pak2-association dependent Nef functions, we employed tandem mass spectrometry analysis of Nef immunocomplexes from Jurkat cells expressing wild-type Nef or Nef mutants defective for the ability to associate with Pak2 (F85L, F89H, H191F and A72P, A75P in NL4-3. We report that wild-type, but not mutant Nef, was associated with 5 components of the exocyst complex (EXOC1, EXOC2, EXOC3, EXOC4, and EXOC6, an octameric complex that tethers vesicles at the plasma membrane, regulates polarized exocytosis, and recruits membranes and proteins required for nanotube formation. Additionally, Pak2 kinase was associated exclusively with wild-type Nef. Association of EXOC1, EXOC2, EXOC3, and EXOC4 with wild-type, but not mutant Nef, was verified by co-immunoprecipitation assays in Jurkat cells. Furthermore, shRNA-mediated depletion of EXOC2 in Jurkat cells abrogated Nef-mediated enhancement of nanotube formation. Using bioinformatic tools, we visualized protein interaction networks that reveal functional linkages between Nef, the exocyst complex, and the cellular endocytic and exocytic trafficking machinery. Conclusions Exocyst complex proteins are likely a key effector of Nef-mediated enhancement of nanotube formation, and possibly microvesicle secretion. Linkages revealed between Nef and the exocyst complex suggest a new paradigm of

  8. Determination of formation constants of uranyl(VI complexes with a hydrophilic SO3-Ph-BTP ligand, using liquid-liquid extraction

    Directory of Open Access Journals (Sweden)

    Steczek Lukasz

    2015-12-01

    Full Text Available Complex formation between uranyl ion, UO22+, and a hydrophilic anionic form of SO3-Ph-BTP4- ligand, L4-, in water was studied by liquid-liquid extraction experiments performed over a range of the ligand and HNO3 concentrations in the aqueous phase, at a constant concentration of nitrate anions at 25°C . The competition for UO22+ ions between the lipophilic TODGA extractant and the hydrophilic L4- ligand leads to the decrease in the uranyl distribution ratios, D, with an increasing L4- concentration. The model of the solvent extraction process used accounts - apart from uranyl complexation by TODGA and SO3-Ph-BTP4- - also for uranyl complexation by nitrates and for the decrease in the concentration of the free L4- ligand in the aqueous phase, due to its protonation, bonding in the uranyl complex and the distribution between the two liquid phases. The unusually strong dependence of the D values on the acidity, found in the experiment, could hardly be explained as due to L4- protonation merely. Three hypotheses were experimentally tested, striving to interpret the data in terms of additional extraction to the organic phase of ion associates of protonated TODGA cation with either partly protonated anionic L4- ligands or anionic UO22+ complexes with NO3 - or L4-. None of them has been confirmed. The analysis of the results, based on the formal correction of free ligand concentrations, points to the formation of 1 : 1 and 1 : 2 uranyl - SO3-Ph-BTP complexes in the aqueous phase. The conditional formation constant of the 1:1 complex has been determined, logßL,1 = 2.95 ± 0.15.

  9. The standard molar enthalpy of formation of a new copper(II) Schiff-base complex and its interaction with bovine serum albumin

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Jin-Qi [Hunan Provincial Key Laboratory of Xiangnan Rare-Precious Metals Compounds and Applications, Department of Chemistry and Life Science, Xiangnan University, Chenzhou 423000, Hunan (China); Li, Chuan-Hua, E-mail: lichuanhua0526@126.com [Hunan Provincial Key Laboratory of Xiangnan Rare-Precious Metals Compounds and Applications, Department of Chemistry and Life Science, Xiangnan University, Chenzhou 423000, Hunan (China); Dong, Jia-Xin [School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin 541004 (China); Qu, Wei; Pan, Lan; Peng, Meng-La; Xie, Ming-An; Tao, Xu; Yu, Cheng-Mao; Zhu, Yi; Zhang, Ping-Hua; Tang, Chun-Guang [Hunan Provincial Key Laboratory of Xiangnan Rare-Precious Metals Compounds and Applications, Department of Chemistry and Life Science, Xiangnan University, Chenzhou 423000, Hunan (China); Li, Qiang-Guo, E-mail: liqiangguo@163.com [Hunan Provincial Key Laboratory of Xiangnan Rare-Precious Metals Compounds and Applications, Department of Chemistry and Life Science, Xiangnan University, Chenzhou 423000, Hunan (China)

    2014-12-20

    Highlights: • A new copper(II) Valen Schiff-base complex was synthesized and characterized. • The standard molar enthalpy of formation of the title complex was obtained. • The interaction between the complex and bovine serum albumin was investigated. - Abstract: A new copper(II) Schiff-base complex [Cu(HL)·NO{sub 3}·MeOH] was prepared by using equivalent molar of Valen Schiff-base ligand [H{sub 2}L=N,N′-ethylene-bis(3-methoxysalicylideneimine)] and Cu(NO{sub 3}){sub 2}·3H{sub 2}O. The structure of the complex was confirmed by single-crystal X-ray diffraction. Based on an ideal and feasible thermochemical cycle, the standard molar enthalpy of formation of the complex was estimated to be: Δ{sub f}H{sub m}{sup θ} [Cu(HL)·NO{sub 3}·MeOH(s), 298.15 K] = –(945.40 ± 2.44) kJ mol{sup −1} by an advanced solution-reaction isoperibol calorimeter. In particular, the interaction between the complex and bovine serum albumin (BSA) was investigated using the fluorescence quenching method. Fluorescence quenching data showed that the quenching mechanism of BSA treated by the complex was static quenching, which was highly accord with the non-radioactive energy transfer theory. And some relevant parameters such as binding sites, binding distance and intermolecular forces between the complex and BSA were also obtained by analyzing the fluorescence spectral data.

  10. EF-Tu dynamics during pre-translocation complex formation: EF-Tu·GDP exits the ribosome via two different pathways.

    Science.gov (United States)

    Liu, Wei; Chen, Chunlai; Kavaliauskas, Darius; Knudsen, Charlotte R; Goldman, Yale E; Cooperman, Barry S

    2015-10-30

    The G-protein EF-Tu, which undergoes a major conformational change when EF-Tu·GTP is converted to EF-Tu·GDP, forms part of an aminoacyl(aa)-tRNA·EF-Tu·GTP ternary complex (TC) that accelerates the binding of aa-tRNA to the ribosome during peptide elongation. Such binding, placing a portion of EF-Tu in contact with the GTPase Associated Center (GAC), is followed by GTP hydrolysis and Pi release, and results in formation of a pretranslocation (PRE) complex. Although tRNA movement through the ribosome during PRE complex formation has been extensively studied, comparatively little is known about the dynamics of EF-Tu interaction with either the ribosome or aa-tRNA. Here we examine these dynamics, utilizing ensemble and single molecule assays employing fluorescent labeled derivatives of EF-Tu, tRNA, and the ribosome to measure changes in either FRET efficiency or fluorescence intensity during PRE complex formation. Our results indicate that ribosome-bound EF-Tu separates from the GAC prior to its full separation from aa-tRNA, and suggest that EF-Tu·GDP dissociates from the ribosome by two different pathways. These pathways correspond to either reversible EF-Tu·GDP dissociation from the ribosome prior to the major conformational change in EF-Tu that follows GTP hydrolysis, or irreversible dissociation after or concomitant with this conformational change.

  11. Limiting nuclearity in formation of polynuclear metal complexes through [2 + 3] cycloaddition: synthesis and magnetic properties of tri- and pentanuclear metal complexes.

    Science.gov (United States)

    Saha, Manideepa; Nasani, Rajendar; Das, Mriganka; Mahata, Arup; Pathak, Biswarup; Mobin, Shaikh M; Carrella, Luca M; Rentschler, Eva; Mukhopadhyay, Suman

    2014-06-07

    A tridentate ligand p-chloro-2-{(2-(dimethylamino)ethylimino)methyl}phenol (HL) was used to generate an octahedral nickel complex [Ni(L)Cl(H2O)2] 1 which was further converted into a square-planar nickel complex [Ni(L)(N3)] 2. The [2 + 3] cycloaddition reaction between metal coordinated azide 2 and different organonitriles under microwave irradiation afforded tri- and pentanuclear nickel(II) complexes 4a-4c. Reaction with benzonitrile and 3-cyano pyridine furnished the trinuclear species [Ni3L2(5-phenyltetrazolato)4(DMF)2] 4a and [Ni3L2{5-(3-pyridyl)-tetrazolato}4(DMF)2]·2H2O 4b, respectively. The nickel centers were found to be linearly disposed to each other and the complex is formed by a 2,3-tetrazolate bridge and a phenoxo bridge between central and terminal nickel atoms. Compound 2 when treated with 1,2-dicyanobenzene under identical conditions furnished a pentanuclear complex [Ni5L4{5-(2-cyanophenyl)-tetrazolato}4(OH)2(H2O)2]·3H2O·DMF 4c. In this pentanuclear compound two dimeric nickel units are connected to the central nickel center by a μ3-hydroxo bridge and a tetrazolate ligand operating via a relatively rare 1,2,3-bridging mode. The compounds were characterized by IR, elemental analysis, thermogravimetric analysis and single crystal X-ray crystallography. The magnetic susceptibility data for compounds 4a-4c show dominant antiferromagnetic interactions between the nickel centers for all the complexes. DFT calculations were performed to investigate the magnetic parameter in one of the complexes 4b by a broken symmetry approach.

  12. Complex Formation in a Liquid-Liquid Extraction System Containing Co(II), 4-(2-Thiazolylazo)resorcinol and Monotetrazolium Salt.

    Science.gov (United States)

    Divarova, Vidka; Stojnova, Kirila; Racheva, Petya; Lekova, Vanya

    2016-01-01

    The ion-associated complex formed between anionic chelate of Co(II)-4-(2-Thiazolylazo)resorcinol (TAR) with the monotetrazolium cation of 2-(4-Iodophenyl)-3-(4-nitrophenyl)-5-phenyl-2H-tetrazolium chloride (INT) in the liquid-liquid extraction system Co(II)-TAR-INT-H(2)O-CHCl(3) was studied by the spectrophotometric method. The optimum extraction conditions of Co(II) were found. The extraction equilibria were studied. The equilibrium constants, the recovery factor and some analytical characteristics were calculated. The validity of Beer's law was checked. The molar ratio of the components in the ternary ion-associated complex Co(II)-TAR-INT was determined. The general formula of the complex was suggested. The effect of various foreign ions and reagents on the process of complex formation in the liquid-liquid extraction system was studied.

  13. The effect of FF-MAS on porcine cumulus-oocyte complex maturation, fertilization and pronucleus formation in vitro.

    Science.gov (United States)

    Faerge, Inger; Strejcek, Frantisek; Laurincik, Jozef; Rath, Detlef; Niemann, Heiner; Schellander, Karl; Rosenkranz, Christine; Hyttel, Poul Maddox; Grøndahl, Christian

    2006-08-01

    Follicular fluid meiosis-activating sterol (FF-MAS) has been isolated from the follicular fluid (FF) of several species including man. FF-MAS increases the quality of in vitro oocyte maturation, and thus the developmental potential of oocytes exposed to FF-MAS during in vitro maturation is improved. The aim of the present study was to investigate the effects of FF-MAS on porcine oocyte maturation and pronucleus formation in vitro. Porcine cumulus-oocyte complexes (COCs) were isolated from abattoir ovaries and in vitro matured for 48 h in NCSU 37 medium supplemented with 1 mg/l cysteine, 10 ng/ml epidermal growth factor and 50 microM 2-mercaptoethanol with or without 10% porcine follicular fluid (pFF). For the first 22 h, 1 mM db-cAMP and 10 I.E PMSG/hCG was added. The medium was supplemented with 1 microM, 3 microM, 10 microM, 30 microM or 100 microM FF-MAS dissolved in ethanol. After maturation the COCs were denuded mechanically using a fine glass pipette under constant pH and in vitro fertilized with fresh semen (5 x 10(5) spermatozoa/ml). The presumptive zygotes were evaluated 18 h after fertilization. The addition of pFF increased the monospermic as well as the polyspermic penetration of oocytes. In the absence of pFF, the addition of FF-MAS decreased the polyspermic penetration rate, whereas FF-MAS in combination with pFF decreased monospermic and increased polyspermic penetration. The degeneration rate of ova decreased in the presence of FF-MAS irrespective of the presence or absence of pFF. In the absence of pFF, FF-MAS at 3-10 microM increased the number of zygotes with advanced maternal pronuclear stages. In supraphysiological doses, i.e. 30-100 microM, FF-MAS dose-dependently and reversibly inhibited nuclear maturation in the absence of pFF.

  14. Providing Formative Assessment to Students Solving Multipath Engineering Problems with Complex Arrangements of Interacting Parts: An Intelligent Tutor Approach

    Science.gov (United States)

    Steif, Paul S.; Fu, Luoting; Kara, Levent Burak

    2016-01-01

    Problems faced by engineering students involve multiple pathways to solution. Students rarely receive effective formative feedback on handwritten homework. This paper examines the potential for computer-based formative assessment of student solutions to multipath engineering problems. In particular, an intelligent tutor approach is adopted and…

  15. The formation of the complex manganites LnSr(2)Mn(2)O(7) (Ln = La, Nd, Gd)

    NARCIS (Netherlands)

    Missyul, A. B.; Zvereva, I. A.; Palstra, T. T. M.

    2012-01-01

    The process of formation of the Ruddlesden-Popper phases LnSr(2)Mn(2)O(7) (Ln = La, Nd, Gd) was investigated by means of X-ray diffraction, thermal analysis and microprobe analysis. Two parallel pathways were found for the reaction. The first one includes the formation of the intermediate K2NiF4-typ

  16. The classical and alternative pathways of complement activation play distinct roles in spontaneous C3 fragment deposition and membrane attack complex (MAC) formation on human B lymphocytes

    DEFF Research Database (Denmark)

    Leslie, Robert Graham Quinton; Nielsen, Claus Henrik

    2004-01-01

    The contributions of the classical (CP) and alternative (AP) pathways of complement activation to the spontaneous deposition of C3 fragments and the formation of membrane attack complexes (MAC) on human B lymphocytes, were assessed by incubating peripheral blood mononuclear cells with autologous ...... of MAC formation was also found to be highly pathway dependent, with the AP being about 15-fold more efficient at initiating this process than the CP. A model accounting for the effectiveness of the AP in both preserving C3 fragment integrity and initiating MAC is presented....

  17. Basic features of low-temperature plasma formation in the course of composite coating synthesis at the active faces of complex contoured hard tools

    Science.gov (United States)

    Brzhozovsky, B. M.; Zimnyakov, D. A.; Zinina, E. P.; Martynov, V. V.; Pleshakova, E. S.; Yuvchenko, S. A.

    2016-04-01

    Basic features of combined-discharge low-temperature plasma formation around the surfaces of complex-contoured metal units are considered. It is shown that it makes the possibilities for synthesis of hardened high-durable coatings of hard tools appropriate for material processing in extreme load-temperature conditions. Experimental study of the coating formation was carried out in combination with the analysis of emission spectra of a low-temperature plasma cloud. Some practical examples of the coating applications are presented.

  18. Standard energies of combustion and standard enthalpies of formation for the complexes RE (Et2dtc)3(phen) (RE=Ho, Er, Tm, Yb, Lu)

    Institute of Scientific and Technical Information of China (English)

    WEI Qing; CHEN Sanping; YANG Xuwu; GAO Shengli; SHI Qizhen

    2005-01-01

    The treatment of RECl3·xH2O (RE = Ho, Er, Tm, Yb, Lu; x = 3-4) with sodium diethyldithiocarbamate RE(Et2dtc)3(phen). IR spectra of the complexes showed that RE3+ coordinated to two sulfur atoms in NaEt2dtc and two ritrogen atoms in o-phen. The constant-volume energies of combustion of the complexes have been determined by a precise rotating-bomb calorimeter at 298.15 K. The standard enthalpies of combustion and standard enthalpies of formation were calculated.

  19. Molar Absorptivity and Concentration-Dependent Quantum Yield of Fe(II) Photo-Formation for the Aqueous Solutions of Fe(III)-Dicarboxylate Complexes

    Science.gov (United States)

    Hitomi, Y.; Arakaki, T.

    2009-12-01

    Redox cycles of iron in the aquatic environment affect formation of reactive oxygen species such as hydrogen peroxide and hydroxyl radicals, which in turn determines lifetimes of many organic compounds. Although aqueous Fe(III)-dicarboxylate complexes are considered to be important sources of photo-formed Fe(II), molar absorptivity and quantum yield of Fe(II) formation for individual species are not well understood. We initiated a study to characterize Fe(II) photo-formation from Fe(III)-dicarboxylates with the concentration ranges that are relevant to the natural aquatic environment. The Visual MINTEQ computer program was used to calculate the equilibrium concentrations of individual Fe(III)-dicarboxylate species. The molar absorptivity of Fe(III)-dicarboxylate species was obtained by UV-VIS spectrophotometer, and the product of the quantum yield and the molar absorptivity of Fe(III)-dicarboxylate species were obtained from photochemical experiments. These experimental data were combined with the calculated equilibrium Fe(III)-dicarboxylate concentrations to determine individual molar absorptivity and quantum yield of Fe(II) photo-formation for a specific Fe(III)-dicarboxylate species. We used initial concentrations of less than 10 micromolar Fe(III) to study the photochemical formation of Fe(II). Dicarboxylate compounds studied include oxalate, malonate, succinate, malate, and phthalate. We report molar absorptivity and concentration-dependent quantum yields of Fe(II) photo-formation of individual Fe(III)-dicarboxylates.

  20. Structural Insight for Roles of DR5 Death Domain Mutations on Oligomerization of DR5 Death Domain-FADD Complex in the Death-Inducing Signaling Complex Formation: A Computational Study.

    Science.gov (United States)

    Yang, Hongyi; Song, Yuhua

    2016-04-01

    Death receptor 5 (DR5)-induced apoptosis that prioritizes the death of tumor cells has been proposed as one of the promising cancer therapies. In this process, oligomerized DR5 death domain (DD) binding to Fas-associated death domain (FADD) leads to FADD activating caspase-8, which marks the formation of the death-inducing signaling complex (DISC) that initiates apoptosis. DR5 DD mutations found in cancer cells have been suggested to play an important pathological role, the mechanism through which those mutants prevent the DR5-activated DISC formation is not clear yet. This study sought to provide structural and molecular insight for the roles of four selected DR5 DD mutations (E355K, E367K, K415N, and L363F) in the oligomerization of DR5 DD-FADD complex during the DISC formation. Results from the molecular dynamics simulations show that the simulated mutants induce conformational, dynamical motions and interactions changes in the DR5 DD-FADD tetramer complex, including changes in a protein's backbone flexibility, less exposure of FADD DED's caspase-8 binding site, reduced H-bonding and hydrophobic contacts at the DR5 DD-FADD DD binding, altered distribution of the electrostatic potentials and correlated motions of residues, and reduced binding affinity of DR5 DD binding to FADD. This study provides structural and molecular insight for the influence of DR5 DD mutations on oligomerization of DR5 DD-FADD complex, which is expected to foster understanding of the DR5 DD mutants' resistance mechanism against DR5-activated DISC formation.

  1. Reactivity of Cys4 Zinc Finger Domains with Gold(III) Complexes : Insights into the Formation of "Gold Fingers"

    NARCIS (Netherlands)

    Jacques, Aurélie; Lebrun, Colette; Casini, Angela; Kieffer, Isabelle; Proux, Olivier; Latour, Jean-Marc; Sénèque, Olivier

    2015-01-01

    Gold(I) complexes such as auranofin or aurothiomalate have been used as therapeutic agents for the treatment of rheumatoid arthritis for several decades. Several gold(I) and gold(III) complexes have also shown in vitro anticancer properties against human cancer cell lines, including cell lines resis

  2. Structural and functional characterization of complex formation between two Kunitz-type serine protease inhibitors from Russell's Viper venom.

    Science.gov (United States)

    Mukherjee, Ashis K; Dutta, Sumita; Kalita, Bhargab; Jha, Deepak K; Deb, Pritam; Mackessy, Stephen P

    2016-01-01

    Snake venom Kunitz-type serine protease inhibitors (KSPIs) exhibit various biological functions including anticoagulant activity. This study elucidates the occurrence and subunit stoichiometry of a putative complex formed between two KSPIs (Rusvikunin and Rusvikunin-II) purified from the native Rusvikunin complex of Pakistan Russell's Viper (Daboia russelii russelii) venom (RVV). The protein components of the Rusvikunin complex were identified by LC-MS/MS analysis. The non-covalent interaction between two major components of the complex (Rusvikunin and Rusvikunin-II) at 1:2 stoichiometric ratio to form a stable complex was demonstrated by biophysical techniques such as spectrofluorometric, classical gel-filtration, equilibrium gel-filtration, circular dichroism (CD), dynamic light scattering (DLS), RP-HPLC and SDS-PAGE analyses. CD measurement showed that interaction between Rusvikunin and Rusvikunin-II did not change their overall secondary structure; however, the protein complex exhibited enhanced hydrodynamic diameter and anticoagulant activity as compared to the individual components of the complex. This study may lay the foundation for understanding the basis of protein complexes in snake venoms and their role in pathophysiology of snakebite.

  3. THE OPEP COARSE-GRAINED PROTEIN MODEL: FROM SINGLE MOLECULES, AMYLOID FORMATION, ROLE OF MACROMOLECULAR CROWDING AND HYDRODYNAMICS TO RNA/DNA COMPLEXES

    OpenAIRE

    Sterpone, Fabio; Melchionna, Simone; Tuffery, Pierre; Pasquali, Samuela; Mousseau, Normand; Cragnolini, Tristan; Chebaro, Yassmine; Saint-Pierre, Jean-Francois; Kalimeri, Maria; Barducci, Alessandro; Laurin, Yohan; Tek, Alex; Baaden, Marc; Nguyen, Phuong Hoang; Derreumaux, Philippe

    2014-01-01

    The OPEP coarse-grained protein model has been applied to a wide range of applications since its first release 15 years ago. The model, which combines energetic and structural accuracy and chemical specificity, allows studying single protein properties, DNA/RNA complexes, amyloid fibril formation and protein suspensions in a crowded environment. Here we first review the current state of the model and the most exciting applications using advanced conformational sampling methods. We then presen...

  4. HTLV-1 Tax Induces Formation of the Active Macromolecular IKK Complex by Generating Lys63- and Met1-Linked Hybrid Polyubiquitin Chains

    Science.gov (United States)

    Tokunaga, Fuminori; Goto, Eiji; Komatsu, Ginga; Saeki, Yasushi; Tanaka, Keiji; Takahashi, Hirotaka; Sawasaki, Tatsuya; Inoue, Satoshi; Oshiumi, Hiroyuki; Seya, Tsukasa; Nakano, Hiroyasu; Tanaka, Yuetsu; Iwai, Kazuhiro

    2017-01-01

    The Tax protein of human T-cell leukemia virus type 1 (HTLV-1) is crucial for the development of adult T-cell leukemia (ATL), a highly malignant CD4+ T cell neoplasm. Among the multiple aberrant Tax-induced effects on cellular processes, persistent activation of transcription factor NF-κB, which is activated only transiently upon physiological stimulation, is essential for leukemogenesis. We and others have shown that Tax induces activation of the IκB kinase (IKK) complex, which is a critical step in NF-κB activation, by generating Lys63-linked polyubiquitin chains. However, the molecular mechanism underlying Tax-induced IKK activation is controversial and not fully understood. Here, we demonstrate that Tax recruits linear (Met1-linked) ubiquitin chain assembly complex (LUBAC) to the IKK complex and that Tax fails to induce IKK activation in cells that lack LUBAC activity. Mass spectrometric analyses revealed that both Lys63-linked and Met1-linked polyubiquitin chains are associated with the IKK complex. Furthermore, treatment of the IKK-associated polyubiquitin chains with Met1-linked-chain-specific deubiquitinase (OTULIN) resulted in the reduction of high molecular weight polyubiquitin chains and the generation of short Lys63-linked ubiquitin chains, indicating that Tax can induce the generation of Lys63- and Met1-linked hybrid polyubiquitin chains. We also demonstrate that Tax induces formation of the active macromolecular IKK complex and that the blocking of Tax-induced polyubiquitin chain synthesis inhibited formation of the macromolecular complex. Taken together, these results lead us to propose a novel model in which the hybrid-chain-dependent oligomerization of the IKK complex triggered by Tax leads to trans-autophosphorylation-mediated IKK activation. PMID:28103322

  5. RNA:DNA complex formation upon transcription of immunoglobulin switch regions: implications for the mechanism and regulation of class switch recombination.

    Science.gov (United States)

    Daniels, G A; Lieber, M R

    1995-01-01

    Central the regulation and mechanism of class switch recombination is the understanding of the relationship between transcription and DNA recombination. We demonstrated previously, using mini-chromosome substrates, that physiologically oriented transcription is required for recombination to occur between switch regions. In this report, we demonstrate the formation of an RNA:DNA complex under in vitro transcription conditions for these same and other switch DNA fragments. We find that cell-free transcription of repetitive murine switch regions (Smu, S gamma 2b and S gamma 3) leads to altered DNA mobility on agarose gels. These altered mobilities are resistant to RNase A but sensitive to RNase H. Transcription in the presence of labeled ribonucleotides demonstrates the stable physical association of the RNA with the DNA. Importantly, complex formation only occurs upon transcription in the physiologic orientation. Reaban and Griffin [1990 Nature, 348, 342-344] found an RNA:DNA hybrid structure that was limited to an atypical 143 nucleotide purine region within a 2.3 kb S alpha segment. Here we demonstrate RNA:DNA hybrid formation in more typical switch sequences (lacking the atypical 143 nucleotide purine tract) from a variety of switch regions that are only 60-70% purine on the non-template strand. These results suggest a general model involving an RNA:DNA complex as an intermediate during class switch recombination. Images PMID:8559658

  6. Measurements of Enthalpy Change of Reaction of Formation, Molar Heat Capacity and Constant-Volume Combustion Energy of Solid Complex Yb(Et2dtc)3(phen)

    Institute of Scientific and Technical Information of China (English)

    Song Weiming; Hu Qilin; Chang Xuan; Chen Sanping; Xie Gang; Gao Shengli

    2006-01-01

    A ternary solid complex Yb(Et2dtc)3(phen) was obtained from the reaction of hydrous ytterbium chloride with sodium diethyldithiocarbamate (NaEt2dtc), and 1, 10-phenanthroline (o-phen·H2O) in absolute ethanol.The bonding characteristics of the complex were characterized by IR.The result shows Yb3+ bands with two sulfur atoms in the Na(Et2dtc)3 and two nitrogen atoms in the o-phen.The enthalpy change of liquid-phase reaction of formation of the complex ΔrHθm (l), was determined as being (-24.838±0.114) kJ·mol-1 at 298.15 K, by an RD-496 Ⅲ type heat conduction microcalormeter.The enthalpy change of the solid-phase reaction of formation of the complex ΔrHθm (s), was calculated as being (108.015±0.479) kJ·mol-1 on the basis of an appropriate thermochemistry cycle.The thermodynamics of liquid-phase reaction of formation of the complex was investigated by changing the temperature during the liquid-phase reaction.Fundamental parameters, the activation enthalpy, ΔHθ≠, the activation entropy, ΔSθ≠, the activation free energy, ΔGθ≠, the apparent reaction rate constant k, the apparent activation energy E, the pre-exponential constant A, and the reaction order n, were obtained by a combination of the reaction thermodynamic and kinetic equations with the data from the thermokinetic experiments.At the same time, the molar heat capacity of the complex cm, p, was determined to be (86.34±1.74) J·mol-1·K-1 by the same microcalormeter.The constant-volume combustion energy of the complex, ΔcU, was determined to be (-17954.08±8.11) kJ·mol-1 by an RBC-Ⅱ type rotating-bomb calorimeter at 298.15 K.Its standard enthalpy of combustion, ΔcHθm, and standard enthalpy of formation, ΔfHθm, were calculated to be (-17973.29±8.11) kJ·mol-1 and (-770.36±9.02) kJ·mol-1, respectively.

  7. The influence of dissolved H2O content in supercritical carbon dioxide to the inclusion complexes formation of ketoprofen/β-cyclodextrin

    Science.gov (United States)

    Goenawan, Joshua; Trisanti, P. N.; Sumarno

    2015-12-01

    This work studies the relation between dissolved H2O content in supercritical carbon dioxide (SC-CO2) with the formation of ketoprofen (KP)/β-cyclodextrin(CD) inclusion complexes. The process involves a physical mixture of these two compounds into contact with the supercritical carbon dioxide which had been previously saturated with H2O over a certain duration. The pressure used for saturation process is 130 bar and saturation temperature was ranged between 30 °C to 50 °C. The inclusion process was achieved by keeping it for 2 hours at 160 bar and 200 bar with inclusion temperature of 50 °C. The results enable us to suggest explanations for the inclusion formation. The inclusion complexes can be formed by contacting the dissolved H2O in SC-CO2 to the physical mixture of KP and CD. An increase in the temperature of saturation process resulted in an increase of dissolved H2O content in the supercritical carbon dioxide. The increasing levels of this water soluble resulted an increase in the inclusion complexes that has been formed. The formation of inclusion complexes includes the water molecules enhancing the emptying of the CD cavities and being replaced by KP, towards a more stable energy state. The drug release used for analyzing the dissolution rate of the KP/CD complexes. The results vary from 79,85% to 99,98% after 45 minutes which is above the rate that has been assigned by Farmakope Indonesia at 70% dissolution rate for KP. The use of SC-CO2 offers a new methods for increasing the rate of dissolution of drugs that are hydrophobic such as KP. CO2 used as a supercritical fluid because of its relatively low cost, easily obtainable supercritical conditions, and lack of toxicity. The material samples were characterized by DSC and Spectrophotometer UV-vis technique.

  8. Geologic, structural, and thermochronologic constraints on the tectonic evolution of the Sierra Mazatán core complex, Sonora, Mexico: New insights into metamorphic core complex formation

    Science.gov (United States)

    Wong, Martin S.; Gans, Phillip B.

    2008-08-01

    The Sierra Mazatán in northwestern Mexico is the southernmost metamorphic core complex in the North American Cordillera. Large-magnitude Tertiary extension at Sierra Mazatán involved both ductile and brittle slip along a major normal fault that presently dips 10°-15° west. Extension was polyphase and involved an early period of extension from 25 to 23 Ma followed by major slip from 21 to 16 Ma. Total slip was ≤20 km and occurred at rates of 3-4 mm/a. This extension predated the plate boundary change to transtension at ˜12 Ma and was largely decoupled from relative Pacific-North American plate motion. Numerous lines of evidence suggest that the presently low-angle normal fault initiated at a steep dip (50°-60°) and was rotated to lower angles during slip. When corrected for this tilting, fault corrugations at Sierra Mazatán had a similar geometry to the segmentation of many active normal faults, which is compatible with their origin as primary fault features. Many aspects of the Sierra Mazatán are comparable to large active normal faults, indicating that this core complex formed owing to prolonged extension on an otherwise typical high-angle normal fault. Therefore, core complexes need not represent a fundamentally unique mode of crustal extension.

  9. The Interaction of Arp2/3 Complex with Actin: Nucleation, High Affinity Pointed End Capping, and Formation of Branching Networks of Filaments

    Science.gov (United States)

    Dyche Mullins, R.; Heuser, John A.; Pollard, Thomas D.

    1998-05-01

    The Arp2/3 complex is a stable assembly of seven protein subunits including two actin-related proteins (Arp2 and Arp3) and five novel proteins. Previous work showed that this complex binds to the sides of actin filaments and is concentrated at the leading edges of motile cells. Here, we show that Arp2/3 complex purified from Acanthamoeba caps the pointed ends of actin filaments with high affinity. Arp2/3 complex inhibits both monomer addition and dissociation at the pointed ends of actin filaments with apparent nanomolar affinity and increases the critical concentration for polymerization at the pointed end from 0.6 to 1.0 μ M. The high affinity of Arp2/3 complex for pointed ends and its abundance in amoebae suggest that in vivo all actin filament pointed ends are capped by Arp2/3 complex. Arp2/3 complex also nucleates formation of actin filaments that elongate only from their barbed ends. From kinetic analysis, the nucleation mechanism appears to involve stabilization of polymerization intermediates (probably actin dimers). In electron micrographs of quick-frozen, deep-etched samples, we see Arp2/3 bound to sides and pointed ends of actin filaments and examples of Arp2/3 complex attaching pointed ends of filaments to sides of other filaments. In these cases, the angle of attachment is a remarkably constant 70 ± 7 degrees. From these in vitro biochemical properties, we propose a model for how Arp2/3 complex controls the assembly of a branching network of actin filaments at the leading edge of motile cells.

  10. Thermodynamics of the complex formation of copper(II) with L-phenylalanine in aqueous ethanol solutions

    Science.gov (United States)

    Burov, D. M.; Ledenkov, S. F.; Vandyshev, V. N.

    2013-05-01

    Constants of the acid dissociation and complexation of L-phenylalanine (HPhe) with copper(II) ions are determined by potentiometry in aqueous ethanol solutions containing 0 to 0.7 molar fraction of alcohol. Changes in the Gibbs energy for the transfer from water to a binary solvent of L-phenylalanine, Phe- anion, and [CuPhe]+ complex are calculated. It is found that the weakening of solvation of the ligand donor groups in solvents with high ethanol contents is accompanied by an increase in the stability of [CuPhe]+ complex.

  11. Calcium-dependent protein kinases responsible for the phosphorylation of a bZIP transcription factor FD crucial for the florigen complex formation.

    Science.gov (United States)

    Kawamoto, Nozomi; Sasabe, Michiko; Endo, Motomu; Machida, Yasunori; Araki, Takashi

    2015-02-09

    Appropriate timing of flowering is critical for reproductive success and necessarily involves complex genetic regulatory networks. A mobile floral signal, called florigen, is a key molecule in this process, and flowering locus T (FT) protein is its major component in Arabidopsis. FT is produced in leaves, but promotes the floral transition in the shoot apex, where it forms a complex with a basic region/leucine-zipper (bZIP) transcription factor, FD. Formation of the florigen complex depends on the supposed phosphorylation of FD; hitherto, however, the responsible protein kinase(s) have not been identified. In this study, we prepared protein extracts from shoot apices of plants around the floral transition, and detected a protein kinase activity that phosphorylates a threonine residue at position 282 of FD (FD T282), which is a crucial residue for the complex formation with FT via 14-3-3. The kinase activity was calcium-dependent. Subsequent biochemical, cellular, and genetic analyses showed that three calcium-dependent protein kinases (CDPKs) efficiently phosphorylate FD T282. Two of them (CPK6 and CPK33) are expressed in shoot apical meristem and directly interact with FD, suggesting they have redundant functions. The loss of function of one CDPK (CPK33) resulted in a weak but significant late-flowering phenotype.

  12. Conductance Studies on Complex Formation between c-Methylcalix[4]resorcinarene and Titanium (III in Acetonitrile-H2O Binary Solutions

    Directory of Open Access Journals (Sweden)

    Naghmeh Saadati

    2013-09-01

    Full Text Available Calixresorcinarenes have proved to be unique molecules for molecular recognition via hydrogen bonding, hydrophobic and ionic interactions with suitable substrates such as cations. The study of the interactions involved in the complexation of different cations with calixresorcinarenes in solvent mixtures is important for a better understanding of the mechanism of biological transport, molecular recognition, and other analytical applications. This article summarizes different aspects of the complexes of the Ti3+ metal cation with c-methylcalix[4]resorcinarene (CMCR as studied by conductometry in acetonitrile (AN–water (H2O binary mixtures at different temperatures. Conductance data show that the metal cation/ligand (ML stoichiometry of the complexes in solution is 1:1 in all cases. Non-linear behaviour was observed for the variation of logKf of the complexes vs. the composition of the binary solvent mixtures. Selectivity of CMCR for the Ti3+ cation is sensitive to solvent composition; in some cases and at certain compositions of the mixed solvent systems, the selectivity order is changed. Values of thermodynamic parameters (, for formation of the CMCR–Ti3+ complexes in AN–H2O binary systems were obtained from the temperature dependence of stability constants, and the results show that the thermodynamics of complexation reactions are affected by the nature and composition of the mixed solvents.

  13. Ternary complex formation between the MADS-box proteins SQUAMOSA, DEFICIENS and GLOBOSA is involved in the control of floral architecture in Antirrhinum majus.

    Science.gov (United States)

    Egea-Cortines, M; Saedler, H; Sommer, H

    1999-10-01

    In Antirrhinum, floral meristems are established by meristem identity genes. Floral meristems give rise to floral organs in whorls, with their identity established by combinatorial activities of organ identity genes. Double mutants of the floral meristem identity gene SQUAMOSA and organ identity genes DEFICIENS or GLOBOSA produce flowers in which whorled patterning is partially lost. In yeast, SQUA, DEF and GLO proteins form ternary complexes via their C-termini, which in gel-shift assays show increased DNA binding to CArG motifs compared with DEF/GLO heterodimers or SQUA/SQUA homodimers. Formation of ternary complexes by plant MADS-box factors increases the complexity of their regulatory functions and might be the molecular basis for establishment of whorled phyllotaxis and combinatorial interactions of floral organ identity genes.

  14. Superoxide dismutase activity of the naturally occurring human serum albumin-copper complex without hydroxyl radical formation.

    Science.gov (United States)

    Kato, Ryunosuke; Akiyama, Matofusa; Kawakami, Hiroyoshi; Komatsu, Teruyuki

    2014-01-01

    The superoxide radical anion (O2(.-)) is biologically toxic and contributes to the pathogenesis of various diseases. Here we describe the superoxide dismutase (SOD) activity of human serum albumin (HSA) complexed with a single Cu(II) ion at the N-terminal end (HSA-Cu complex). The structure of this naturally occurring copper-coordinated blood serum protein has been characterized by several physicochemical measurements. The O2(.-) dismutation ability of the HSA-Cu (1:1) complex is almost the same as that of the well-known SOD mimics, such as Mn(III) -tetrakis(N-methylpyridinium)porphyrin. Interestingly, the HSA-Cu complex does not induce a subsequent Fenton reaction to produce the hydroxyl radical (OH(.)), which is one of the most harmful reactive oxygen species.

  15. Selective and non-extractive spectrophotometric determination of cefdinir in formulations based on donor-acceptor complex formation

    OpenAIRE

    2010-01-01

    Cefdinir has broad spectrum of activity and high prescription rates, hence its counterfeiting seems imminent. We have proposed a simple, fast, selective and non-extractive spectrophotometric method for the content assay of cefdinir in formulations. The method is based on complexation of cefdinir and Fe under reducing condition in a buffered medium (pH 11) to form a magenta colored donor-acceptor complex (λ max = 550 nm; apparent molar absorptivity = 3720 L mol-1 cm-1). No other cephalosp...

  16. DEAD-box helicase DDX27 regulates 3′ end formation of ribosomal 47S RNA and stably associates with the PeBoW-complex

    Energy Technology Data Exchange (ETDEWEB)

    Kellner, Markus; Rohrmoser, Michaela [Department of Molecular Epigenetics, Helmholtz Center Munich, Center for Integrated Protein Science Munich (CIPSM), Marchioninistr. 25, Munich 81377 (Germany); Forné, Ignasi [Adolf Butenandt Institute, Ludwig Maximilians University of Munich, Center for Integrated Protein Science Munich (CIPSM), Schillerstr. 44, Munich 80336 (Germany); Voss, Kirsten; Burger, Kaspar; Mühl, Bastian; Gruber-Eber, Anita [Department of Molecular Epigenetics, Helmholtz Center Munich, Center for Integrated Protein Science Munich (CIPSM), Marchioninistr. 25, Munich 81377 (Germany); Kremmer, Elisabeth [Institute of Molecular Immunology, Helmholtz Center Munich, Marchioninistr. 25, Munich 81377 (Germany); Imhof, Axel [Adolf Butenandt Institute, Ludwig Maximilians University of Munich, Center for Integrated Protein Science Munich (CIPSM), Schillerstr. 44, Munich 80336 (Germany); Eick, Dirk, E-mail: eick@helmholtz-muenchen.de [Department of Molecular Epigenetics, Helmholtz Center Munich, Center for Integrated Protein Science Munich (CIPSM), Marchioninistr. 25, Munich 81377 (Germany)

    2015-05-15

    PeBoW, a trimeric complex consisting of pescadillo (Pes1), block of proliferation (Bop1), and the WD repeat protein 12 (WDR12), is essential for processing and maturation of mammalian 5.8S and 28S ribosomal RNAs. Applying a mass spectrometric analysis, we identified the DEAD-box helicase DDX27 as stably associated factor of the PeBoW-complex. DDX27 interacts with the PeBoW-complex via an evolutionary conserved F×F motif in the N-terminal domain and is recruited to the nucleolus via its basic C-terminal domain. This recruitment is RNA-dependent and occurs independently of the PeBoW-complex. Interestingly, knockdown of DDX27, but not of Pes1, induces the accumulation of an extended form of the primary 47S rRNA. We conclude that DDX27 can interact specifically with the Pes1 and Bop1 but fulfils critical function(s) for proper 3′ end formation of 47S rRNA independently of the PeBoW-complex. - Highlights: • DEAD-box helicase DDX27 is a new constituent of the PeBoW-complex. • The N-terminal F×F motif of DDX27 interacts with the PeBoW components Pes1 and Bop1. • Nucleolar anchoring of DDX27 via its basic C-terminal domain is RNA dependent. • Knockdown of DDX27 induces a specific defect in 3′ end formation of 47S rRNA.

  17. Formation of a covalent complex between the terminal protein of pneumococcal bacteriophage Cp-1 and 5'-dAMP

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, P.; Hermoso, J.M.; Garcia, J.A.; Garcia, E.; Lopez, R.; Salas, M.

    1986-04-01

    Incubation of extracts of Cp-1-infected Streptococcus pneumoniae with (..cap alpha..-/sup 32/P)dATP produced a labeled protein with the electrophoretic mobility of the Cp-1 terminal protein. The reaction product was resistant to treatment with micrococcal nuclease and sensitive to treatment with proteinase K. Incubation of the /sup 32/P-labeled protein with 5 M piperidine for 4 h at 50/sup 0/C released 5'-dAMP, indicating that a covalent complex between the terminal protein and 5'-dAMP was formed in vitro. When the four deoxynucleoside triphosphates were included in the reaction mixture, a labeled complex of slower electrophoretic mobility in sodium dodecyl sulfate-polyacrylamide gels than the terminal protein-dAMP complex was also found, indicating that the Cp-1 terminal protein-dAMP complex can be elongated and, therefore, that it is an initiation complex. Treatment of the /sup 32/P-labeled terminal protein-dAMP complex with 5.8 M HCl at 110/sup 0/C for 2 h yielded phosphothreonine. These results, together with the resistance of the terminal protein-DNA linkage to hydroxylamine, suggest that the Cp-1 terminal protein is covalently linked to the DNA through a phosphoester bond between L-threonine and 5'-dAMP, namely, a O-5'-deoxyadenylyl-L-threonine bond.

  18. Reservoir attributes of a hydrocarbon-prone sandstone complex: case of the Pab Formation (Late Cretaceous) of Southwest Pakistan

    DEFF Research Database (Denmark)

    Umar, Muhammad; Khan, Abdul Salam; Kelling, Gilbert;

    2016-01-01

    Links between the architectural elements of major sand bodies and reservoir attributes have been explored in a field study of the hydrocarbon-yielding Late Cretaceous Pab Formation of southwest Pakistan. The lithofacies and facies associations represented in the Pab Formation are the main...... porosity values than more shale-rich successions. Diagenetic studies of Pab sandstones reveal that intense mechanical compaction and cementation have reduced primary porosity and reservoir quality. Conversely, dissolution of detrital feldspar grains and volcanic fragments during burial and later uplift...

  19. Iridium mediated phenolic O-H activation and cyclometalation of 2-(naphthyl-1'-azo)-4-methylphenol - Formation of organoiridium complexes

    Indian Academy of Sciences (India)

    Rama Acharyya; Shie-Ming Peng; Gene-Hsiang Lee; Samaresh Bhattacharya

    2009-07-01

    Reaction of 2-(naphthyl-1'-azo)-4-methylphenol with [Ir(PPh3)3Cl] in refluxing ethanol in the presence of a base (NEt3) affords an organoiridium complex of type [Ir(PPh3)2(L)(H)], where L represents the coordinated 2-(naphthyl-1'-azo)-4-methylphenolate ligand. A similar reaction carried out in toluene affords the [Ir(PPh3)2(L)(H)] complex along with a similar complex of type [Ir(PPh3)2(L)Cl]. Structures of both the [Ir(PPh3)2(L)(H)] and [Ir(PPh3)2(L)Cl] complexes have been determined by X-ray crystallography. In both the complexes, 2-(naphthyl-1'-azo)-4-methylphenol is coordinated to iridium, via C-H activation at the 2' position of the naphthyl ring, as a dianionic tridentate C, N, O-donor and the two triphenylphosphines are trans. The organoiridium complexes show intense MLCT transitions in the visible region. Cyclic voltammetry on the [Ir(PPh3)2(L)(H)] and [Ir(PPh3)2(L)Cl] complexes shows a reversible Ir(III)-Ir(IV) oxidation respectively at 0.55 and 0.73 V vs SCE. An irreversible oxidation of the coordinated 2-(naphthyl-1'-azo)-4-methylphenolate ligand is observed above 1.0 V vs SCE and an irreversible reduction of the same is observed near -1.0 V vs SCE.

  20. Complex Formation Between Lysozyme and Stabilized Micelles with a Mixed Poly(ethylene oxide)/Poly(acrylic acid) Shell.