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61.
ABSTRACTIn this work, with Ni (110) as a model catalyst surface and CO2 as an adsorbate, a performance study of Density Functional Theory methods (functionals) is performed. CO being a possible intermediate in CO2 conversion reactions, binding energies of both, CO2 and CO, are calculated on the Ni surface and are compared with experimental data. OptPBE-vdW functional correctly predicts CO2 binding energy on Ni (?62?kJ/mol), whereas CO binding energy is correctly predicted by the rPBE-vdW functional (?138?kJ/mol). The difference in computed adsorption energies by different functionals is attributed to the calculation of gas phase CO2. Three alternate reaction systems based on a different number of C=O double bonds present in the gas phase molecule are considered to replace CO2. The error in computed adsorption energy is directly proportional to the number of C=O double bonds present in the gas phase molecule. Additionally, both functionals predict similar carbon–oxygen activation barrier (40?kJ/mol) and equivalent C1s shifts for probe species (?2.6?eV for CCH3 and +1.5?eV CO3?), with respect to adsorbed CO2. Thus, by including a correction factor of 28?kJ/mol for the computed CO2 gas phase energy, we suggest using rPBE-vdW functional to investigate CO2 conversion reactions on different metals. 相似文献
62.
Emma?M.M. Burkitt?Wright Helen?L. Spencer Sarah?B. Daly Forbes?D.C. Manson Leo?A.H. Zeef Jill Urquhart Nicoletta Zoppi Richard Bonshek Ioannis Tosounidis Meyyammai Mohan Colm Madden Annabel Dodds Kate?E. Chandler Siddharth Banka Leon Au Jill Clayton-Smith Naz Khan Leslie?G. Biesecker Meredith Wilson Marianne Rohrbach Marina Colombi Cecilia Giunta Graeme?C.M. Black 《American journal of human genetics》2011,89(2):346
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64.
Philah Lee Subramanian Mohan Raj Shengfang Zhou Somasundar Ashok Selvakumar Edwardraja Sunghoon Park 《Biotechnology and Bioprocess Engineering》2014,19(1):1-7
This study examined the role and physiological relevance of 3-hydroxyisobutyrate dehydrogenase-I (3HIBDHI) of Pseudomonas denitrificans ATCC 13867 in the degradation of 3-hydroxypropionic acid (3-HP) during 3-HP production. The gene encoding 3HIBDH-I of P. denitrificans ATCC 13867 was cloned and expressed in Escherichia coli BL21 (DE3). The recombinant 3HIBDH-I was then purified on a Ni-NTA-HP column and characterized for its choice of substrates, cofactors, metals, reductants, and the optimal temperature and pH. The recombinant 3HIBDH-I showed a high catalytic constant (k cat/K m) of 604.1 ± 71.1 mM/S on (S)-3-hydroxyisobutyrate, but no detectable activity on (R)-3-hydroxyisobutyrate. 3HIBDH-I preferred NAD+ over NADP+ as a cofactor for its catalytic activity. The k cat/K m determined for 3-HP was 15.40 ± 1.43 mM/S in the presence of NAD+ at 37°C and pH 9.0. In addition to (S)-3-hydroxyisobutyrate and 3-HP, 3HIBDH-I utilized l-serine, methyl-d,l-serine, and methyl-(S)-(+)-3-hydroxy-2-methylpropionate; on the other hand, the k cat/K m values determined for these substrates were less than 5.0mM/S. Ethylenediaminetetraacetic acid, 2-mercaptoethanol, dithiothreitol and Mn2+ increased the activity of 3HIBDHI significantly, whereas the presence of Fe2+, Hg2+ and Ag+ in the reaction mixture at 1.0 mM completely inhibited its activity. This study revealed the characteristics of 3HIBDH-I and its significance in 3-HP degradation. 相似文献
65.
Shaohong Cheng Chandrasekhar Kesavan Subburaman Mohan Xuezhong Qin Catrina M. Alarcon Jon Wergedal Weirong Xing 《PloS one》2013,8(7)
To test if ephrin B1 overexpression enhances bone mass, we generated transgenic mice overexpressing ephrin B1 under the control of a 3.6 kb rat collagen 1A1 promoter (Col3.6-Tgefnb1). Col3.6-Tgefnb1 mice express 6-, 12- and 14-fold greater levels of full-length ephrin B1 protein in bone marrow stromal cells, calvarial osteoblasts, and osteoclasts, respectively. The long bones of both genders of Col3.6-Tgefnb1 mice have increased trabecular bone volume, trabecular number, and trabecular thickness and decreased trabecular separation. Enhanced bone formation and decreased bone resorption contributed to this increase in trabecular bone mass in Col3.6-Tgefnb1 mice. Consistent with these findings, our in vitro studies showed that overexpression of ephrin B1 increased osteoblast differentiation and mineralization, osterix and collagen 1A1 expression in bone marrow stromal cells. Interaction of ephrin B1 with soluble clustered EphB2-Fc decreased osteoclast precursor differentiation into multinucleated cells. Furthermore, we demonstrated that the mechanical loading-induced increase in EphB2 expression and newly formed bone were significantly greater in the Col3.6-Tgefnb1 mice than in WT littermate controls. Our findings that overexpression of ephrin B1 in bone cells enhances bone mass and promotes a skeletal anabolic response to mechanical loading suggest that manipulation of ephrin B1 actions in bone may provide a means to sensitize the skeleton to mechanical strain to stimulate new bone formation. 相似文献
66.
Inhibitory insulin-like growth factor-binding protein: cloning, complete sequence, and physiological regulation. 总被引:5,自引:0,他引:5
D LaTour S Mohan T A Linkhart D J Baylink D D Strong 《Molecular endocrinology (Baltimore, Md.)》1990,4(12):1806-1814
In this study we report the preparation of a human osteosarcoma cell cDNA library and describe the isolation and sequence determination of a clone encoding the complete sequence of a novel human insulin-like growth factor (IGF)-binding protein (hIGFBP-4). Previous work indicated that hIGFBP-4 is the predominant IGFBP expressed by human osteoblast-like cells, and that IGFBP-4 binds and inhibits the mitogenic activities of IGF-I and IGF-II. Sequence determination revealed that hIGFBP-4 is a unique gene product with significant amino- and carboxy-terminal sequence similarity to three other known IGFBPs. Identical alignment of 18 cysteines in IGFBP-4 and the three other IGFBPs is a key structural feature of this protein family. In vitro studies of human osteoblast-like cells suggest that PTH regulates the expression of hIGFBP-4 and that the PTH effect is mediated through a cAMP mechanism. hIGFBP-4 mRNA was also expressed in skin fibroblasts, and thus, this inhibitory IGFBP could be an important physiological regulator of IGF actions in bone cells and other cell types as well. 相似文献
67.
68.
Chokkalingam Uvarani Karuppannan Arumugasamy Kumarasamy Chandraprakash Mathan Sankaran Athar Ata Palathurai Subramaniam Mohan 《化学与生物多样性》2015,12(3):358-370
Phytochemical investigation of the CHCl3 fraction of Swertia corymbosa resulted in the isolation of a new 3‐allyl‐2,8‐dihydroxy‐1,6‐dimethoxy‐9H‐xanthen‐9‐one ( 1 ), along with four known xanthones, gentiacaulein ( 3 ), norswertianin ( 4 ), 1,3,6,8‐tetrahydroxyxanthone ( 5 ), and 1,3‐dihydroxyxanthone ( 6 ). Structure of compound 1 was elucidated with the aid of IR, UV, NMR, and MS data, and chemical transformation via new allyloxy xanthone derivative ( 2 ). Compounds 1 – 6 exhibited various levels of antioxidant and anti‐α‐glucosidase activities. Absorption and fluorescence spectroscopic studies on 1 – 6 indicated that these compounds could interact with calf thymus DNA (CT‐DNA) through intercalation and with bovine serum albumin (BSA) in a static quenching process. Compound 1 was found to be significantly cytotoxic against human cancer cell lines HeLa, HCT116, and AGS, and weakly active against normal NIH 3T3 cell line. 相似文献
69.
Summary Relative efficiency of five chemical extractants for the extraction of available Zn in four different soils and its uptake by rice seedlings was studied in a pot culture experiment. The Zn extracted by dithizone-ammonium acetate showed a significant relationship with plant uptake whereas the values for other extractants except NH4OAc (pH4.8) did not approach the level of significance. Among the soil properties studied, pH and CaCO3 correlated negatively and organic matter and CEC positively with Zn uptake by rice plants.Contribution from the Soil Science and Agricultural Chemistry Dept., Banaras Hindu University, Varanasi-221005, India.Lecturer and Research Scholar of the Soil Science and Agricultural Chemistry Department, respectively.Lecturer and Research Scholar of the Soil Science and Agricultural Chemistry Department, respectively. 相似文献
70.
Docosahexaenoic acid up‐regulates both PI3K/AKT‐dependent FABP7–PPARγ interaction and MKP3 that enhance GFAP in developing rat brain astrocytes 下载免费PDF全文