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Theoretical studies on the mechanism of the thermal decarboxylation and decarbonylation of a number of α-keto-acids

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Chinese Journal of Chemistry 1995年第6期13卷 487-492页

作者： CHEN,Li-Tao CHEN,Guang-Ju FU,Xiao-YuanChemistry department,Beijing Normal university,Beijing 100875,China Chemistry department Beijing Normal University Beijing 100875 China

Both processes of decarboxylation and decarbonylation of a number of acids including RCOCO2H,R=H,CH3,CH2F,CF3,CH=CH2,Ph,OH have been studied by semi-empirical MO theory AMI method to verify the reaction mechanism of each process and the effect of different substituents on *** calculated results are consistent with the experimental reports and can be summed up as follows:(1) The decarboxylation of these acids to form aldehydes and carbon dioxide is concerted and takes place through a 4-membered ring transition state in which a partial negative charge develops on the carbon of the α-carbonyl group,so that the inductive effect of some substituents is favourable for this process.(2) Their decarbonylation into carboxylic acids and carbon monoxide however is the attack of the OH on the carbon of the alkyl portion of the acid,forming a 3-membered ring transition state.(3) The activation energy of decarbonylation is lower than that of decarboxylation,since oxygen is more nucleophilic than hydrogen and also the strong OH bond need not to be broken.

关键词： Decarboxylation decarbonylation a-keto-acid

INFLUENCE　OF　CYCLE　PHASE　TRANSFORMATION　ON　TEXTURE　AND　YIELD　STRESS　ANISOTROPY　IN　TITANIUM　SHEET

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中国有色金属学会会刊：英文版 1994年第4期4卷 72-77页

作者： Zhu, Zhishou Gu,Jialin Chen, Nanping (department of Materials Science and Engineering,Tsinghua university,Beijing 100084)

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关键词： cycle phase transformation texture crystallite orientation distribution function titanium

Engagement of PSGL-1 enhances β2-integrin-involved adhesion of neutrophils to recombinant ICAM-1

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Acta Pharmacologica Sinica 2006年第5期27卷 617-622页

作者： Xiao-guang WANG~(2,3) Yan-ping CHENG~4 Xue-qing BA~(2,5) ~2Institute of Genetics and Cytology Northeast Normal university,Changchun 130024,China:~3department of Biology,Changchun Normal College,Changchun 130032,China ~4College of Life Science.Jilin Normal university,Siping 136001,China Institute of Genetics and Cytology Northeast Normal University Changchun 130024 China department of Biology Changchun Normal College Changchun 130032 China College of Life Science Jilin Normal University Siping 136001 China

Aim:The interactions of selectins and their ligands initiate the process of leuko-cyte migrating into inflamed tissue.P-selectin glycoprotein ligand 1 （PSGL-1） isthe best characterized ligand of selectins,and has been demonstrated to mediatethe adhesion of leukocytes to all three selectins in ***-1 not only func-tions as an anchor molecule to capture the leukocytes to the activated endothelialcells by its interaction with selectins,but also transduces the signals to *** present work aimed to investigate the mechanism by whichPSGL-1-mediated signal activates neutrophils and enhances the adhesion to theendothelial ***:We detected the effects of the engagement of PSGL-1with monoclonal antibodies （mAb） or P-selectin on the adhesion of neutrophils tothe recombinant intercellular adhesion molecule-1 （ICAM-1）,and on the expres-sion of β***,the role of cytoskeleton in these process wasstudied by using inhibitor cytochalasin ***:The engagement of PSGL-Iincreased the expression of β2-integrin on the surface of neutrophils and en-hanced the adhesion of neutrophils to the recombinant *** againstCD18 impaired the adhesion of PSGL-1-engaged neutrophils to ***,the inhibitor cytochalasin B largely blocked the increase of CD 18 expression aswell as the adhesion of PSGL-1-engaged neutrophils to ***:The PSGL-1-transduced signals can enhance β2-integrin-involved adhesion ofneutrophils to the recombinant ICAM-1,and this process depends on the dynam-ics of cytoskeleton.

关键词： P-selectin ligand protein intercellular signaling peptides and proteins intercellular adhesion molecule-1 CD 18 antigens

Study of Cathodic Polarization Curves During Pulse Plating of Chromium

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Chemical Research in Chinese Universities 1989年第4期5卷 319-324页

作者： Zhang Hengbin (department of Chemistry, Jilin university, Changchun)Der-Tau Chin (department of Chemical Engineering, Clarkson university, Potsdam, New York)

A study has been made of the cathodic polarization curves during the pulse plating of chromium from an aqueous chromic acid bath containing 250 g/L CrO3 and 2. 5 g/L H2SO4 at 22℃ over the range of pulse periods from 1 ms to 50 ms. The duty cycle was kept at 50%. The methods of potentiostatic pulse potential control and galvanostatic pulse current control were used to determine the polarization curves of a platinum and a copper rotating disk electrode in the chromium plating solution. The results indicated that pulse potential and pulse current inhibited the formation of a cathode film and shifted the potential of the hydrogen evolution reaction toward the positive direction by about 500 mV. The potential and current pulses behaved as a depolarter of H+ reduction reaction. The present results agreed with a previous experimental observation that the coulombic efficiency of the chromium deposition reaction was reduced and the coulombic efficiency of the hydorgen evolution reaction was increased in pulse plating of chromium.

关键词： Pulse Plating Chromium

Effect of curcumin on multidrug resistance in resistant human gastric carcinoma cell line SGC7901/VCR

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Acta Pharmacologica Sinica 2005年第8期26卷 1009-1016页

作者： Xiao-qing TANG~1, Hu BI~1, Jian-qiang FENG~2, Jian-guo CAO~3 ~1 department of Physiology, Nanhua university, Hengyang 421001, China ~2 department of Physiology, Zhongshan Medical College, Sun Yat sen university, Guangzhou 510080, China ~3 Institute of Oncology, Nanhua university, Hengyang 421001, China department of Physiology Nanhua University Hengyang 421001 China

Aim: To investigate the reversal effects of curcumin on multidrug resistance （MDR） in a resistant human gastric carcinoma cell line. Methods: The cytotoxic effect of vincristine （VCR） was evaluated by MTT assay. The cell apoptosis induced by VCR was determined by propidium iodide （PI）-stained flow cytometry （FCM） and a morphological assay using acridine orange （AO）/ethidium bromide （EB） dual staining. P-glycoprotein （P-gp） function was demonstrated by the accumulation and efflux of rhodamine 123 （Rh123） using FCM. The expression of P-gp and the activation of caspase-3 were measured by FCM using fluorescein isothiocyanate （FITC）-conjugated anti-P-gp and anti-cleaved caspase-3 antibodies, respectively. Results: Curcumin, at concentrations of 5 μmol/L, 10 μmol/L, or 20 μmol/L, had no cytotoxic effect on a parent human gastric carcinoma cell line （SGC7901） or its VCR-resistant variant cell line （SGC7901/VCR）. The VCR-IC50value of the SGC7901/VCR cells was 45 times more than that of the SGC7901ceUs and the SGC7901/VCR cells showed apoptotic resistance to VCR. SGC7901/VCR cells treated with 5 μmol/L, 10μmol/L, or 20 μmol/L curcumin decreased the IC50value of VCR and promoted VCR-mediated apoptosis in a dose-dependent manner. Curcumin （10 μmol/L） increased Rh123 accumulation and inhibited the effiux of Rh123 in SGC7901/VCR cells, but did not change the accumulation and efflux of Rh123 in SGC7901 ceils. P-gp was overexpressed in SGC7901/VCR cells, whereas it was downregulated after a 24-h treatment with curcumin （10 μmol/L）. Resistant cells treated with 1 μmol/L VCR alone showed 77% lower levels of caspase-3 activation relative to SGC7901 cells, but the activation of caspase-3 in the resistant cell line increased by 44% when cells were treated with VCR in combination with curcumin. Conclusion: Curcumin can reverse the MDR of the human gastric carcinoma SGC7901/VCR cell line. This might be associated with decreased P-gp function and expression, and the promotion of caspase-3

关键词： curcumin multidrug resistance apoptosis P-glycoprotein caspase-3

Direct Electrochemistry of Myoglobin in DDAB-Clay Composite Films

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Chinese Chemical Letters 2000年第1期11卷 79-80页

作者： Nai Fei HU Zhen LI Hong Yan MA (department of Chemistry, Beijing Normal university, Beijing, 100875) Beijing Normal Univ Dept Chem Beijing 100875 Peoples R China

Ordered films were made by casting a mixture of aqueous dispersions of didodecyldimethylammonium bromide (DDAB)-clay composite and myoglobin (Mb) solution on pyrolytic graphite (PG) electrodes. The Mb-DDAB-clay film electrodes showed stable and reversible cyclic voltammetric responses in buffers and can catalyze the reduction of id (TCA).

关键词： myoglobin didodecyldimethylammonium bromide clay composite film electrode electrochemistry electrocatalysis

Filter Trust-region SQP Method with 3-1 Piecewise Linear NCP Function

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Filter Trust-region SQP Method with 3-1 Piecewise Linear NCP...

Enantiomeric Excess Determination of Amino Acids with Chiral Cyclopalladated Ferrocenylimine

第八届中国青年运筹信息管理学者大会

作者： Jiang Aiping Pu Dingguo department of Applied mathematics, Tongji university, Shanghai 200092

＜正＞In this paper, a new filter trust-region SQP method is proposed for solving constrained nonlinear programming. The new algorithm based on 3-1 piecewise linear NCP function combines the filter strategy with trust-region SQP method to promote global convergence. We also prove that the algorithm has superlinear convergence rate under some mild conditions.

关键词： Constrained nonlinear optimization filter trust-region SQP convergence superlinear

来源： cnki会议评论

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Chinese Chemical Letters 1999年第2期10卷 127-128页

作者： Xiu Ling CUI Yang Jie WU Liang Ru YANG(department of Chemistry, Zhengzhou university, Zhengzhou, 450052) Zhengzhou Univ Dept Chem Zhengzhou 450052 Peoples R China

An efficient NMR determination of the enantiomeric excess of the amino acids can be achieved using chloro-bridged dimer R- (+)-{Pd [(eta(5)-C5H5)Fe (eta(5)-C5H3CMe=NAr)] (mu-Cl)}2 (Ar=p-CH3C6H4) (R-1).

关键词： determination e.e% amino acids chiral cyclopalladated ferrocenylimine

GAS-PHASE PHOTOCATALYTIC OXIDATION OF CHCl CCl2 AND Ph Me BY SUPPORTED TITANIA

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Chinese Journal of Catalysis 1996年第5期 105-109页

作者： Li Lin (department of Chemical Engineering, Tsinghua university, Beijing 100084) Yue Po lock (department of Chemical Engineering, The HongKong university of Science and Technology, Kowloon, HongKong)

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关键词： Trichloroethylene Toluene Photocatalytic oxidation Titania Supported catalyst