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Observation of contrast variations of a copper(Ⅱ)complex by scanning tunneling microscopy

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Chinese Science Bulletin 2003年第6期48卷 531-534页

作者： WANG Zhigang, ZENG Qingdao, WANG Chen, ZHOU Chunqing, WAN Lijun & BAI Chunli The Center for molecular sciences, institute of Chemistry, Chinese Academy of sciences, Beijing 100080, china The Center for molecular sciences Institute of Chemistry Chinese Academy of Sciences Beijing China

This report presents experimental observations of dramatic variations in STM images of bis [1,3- di(p-n-tetradecyloxyphenyl)propane-1,3-dionato] copper(Ⅱ) (abbreviated to C14O-Cu) physisorbed on HOPG as the bias voltage is changed. Several representative image patterns were obtained for the rich changes of the internal contrast of the molecule. Submolecular features of the molecular cores and the interdigitated alkyl parts are clearly visible.

关键词：扫描隧道显微镜铜配合物实验观察对比度变化 STM图像吸附物

STUDY OF PHASES IN U-10wt%Zr ALLOY BY NEUTRON DIFFRACTION

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Acta Metallurgica sinica(English Letters) 1995年第3期8卷 174-180页

作者： XIE Guoqiang YANG Jijian ZHANG Baisheng LI Wendan(china institute of atomic Energy, Beijing) china Inst of atomic Energy Beijing China

U 10wt%Zr alloy has been analysed by neutron diffraction method to determine the constituent phases and their crystal *** collected diffraction data are processed using Rietveld' s profile technique (with program“ Fullprof ”). Four phases,α-U,δ, γand α Zr, in the alloy at room temperature and the corresponding volume fractions as well their structural parameters are obtained from the data analysis, For the δ-phase, a partially ordered unusual hexagonal structure of the modified C32(AlB2) type is confirmed.

关键词： U-10wt%Zr alloy neutron diffraction δ-phase

TRANSIENT EFFECT OF A BOGER FLUID FLOWING AROUND A CONFINED CYLINDER

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Chinese Journal of Polymer Science 2001年第4期19卷 377-384页

作者： Xian-feng Li Huai-tian Bu De-lu Zhao State Key Laboratory of Polymer Physics and Chemistry Center for molecular Science,institute of Chemistry, Chinese Academy of sciences, Beijing 100080, china 中科院化学所高分子物理与化学国家重点实验室北京

This paper is concerned with the numerical simulation of the transient effect of an inertialess Boger flow past a confined circular cylinder and the comparison of predictions with particle image velocimetry (PIV) measurements given by Shiang et al.. Dynamic simulation based on the Oldroyd-B constitutive model was carried out using a Lagrangian-Eulerian algorithm. The evolution of velocity field was obtained for the flow at two Deborah (De) numbers, i.e. De = 1.2 and 3.0. At low De, the flow reached steady state rapidly, and showed a symmetric flow regime. However, at high De, the time required to reach steady flow behind the cylinder increased significantly, and the distribution of the velocity field appears to be asymmetric with respect to the stagnation line. Fairly good agreement between the numerical results and the experimental observations is reported. It can be concluded that both the experimental measurements and the present simulations indicate that the elasticity of the polymeric flow strongly affect the flow regime of viscoelastic flow around a confined cylinder.

关键词： transient effect flow around a cylinder Lagrangian-Eulerian algorithm Oldroyd-B model

RHEOLOGICAL BEHAVIOR OF EPOXY RESIN WATERBORNE DISPERSIONS

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Chinese Journal of Polymer Science 2001年第5期19卷 471-476页

作者： Zhen-zhong Yang Yuan-ze Xu De-lu Zhao State Key Laboratory of Polymer Physics & Chemistry, Center for molecular Science institute of Chemistry, Chinese Academy of sciences, Beijing 100080 china 中科院化学所高分子物理与化学国家重点实验室北京

The waterborne dispersions of epoxy resin were prepared by the phase inversion emulsification technique. Rheological behavior and its relationship with the structural change of the systems were studied. It was shown that the concentrated dispersions were highly viscoelastic and pseudoplastic, which was attributed to the formation of a physical network among the waterborne particles via hydrogen bond. The dilute dispersions were Newtonian fluids. The discrete clusters composed of small waterborne particles were found in diluted dispersions. With increasing solid content, there existed a structural transition via percolation through a cluster-cluster aggregation mode to form the physical network, which was qualitatively evidenced by the TEM morphologies.

关键词： epoxy resin waterborne dispersion rheological behavior cluster-cluster aggregation percolation transition

Characterization of ATPase Activity of Recombinant Human Pif1

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Acta Biochimica et Biophysica sinica 2006年第5期38卷 335-341页

作者： Yu HUANG Deng-Hong ZHANG Jin-Qiu ZHOU Max-Planck Junior Research Group at the State Key Laboratory of molecular Biology,institute of Biochemistry and Cell Biology,Shanghai institutes for Biological sciences,Chinese Academy of sciences,Shanghai 200031,china Max-Planck Junior Research Group at the State Key Laboratory of molecular Biology Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of SciencesShanghai 200031 China

Saccharomyces cerevisiae Piflp helicase is the founding member of the Pifl subfamily that isconserved from yeast to *** potential human homolog of the yeast PIFI gene has been cloned fromthe cDNA library of the Hek293 cell ***,we described a purification procedure of glutathione S-transferase（GST）-fused N terminal truncated human Pifl protein（hPif1ΔN）from yeast and characterizedthe enzymatic kinetics of its ATP hydrolysis *** ATPase activity of human Pif1 is dependent ondivalent cation,such as Mg2+,Ca2+and single-stranded *** for ATP for the ATPase activity isapproximately 200 μ*** the ATPase activity is essential for hPifl’s helicase activity,these results willfacilitate the further investigation on hPif1.

关键词： Pifl helicase telomere telomerase ATPase

nifH Promoter Activity Is Regulated by DNA Supercoiling in Sinorhizobium meliloti

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Acta Biochimica et Biophysica sinica 2005年第4期37卷 221-226页

作者： Yan-Jie LIU Biao HU Jia-Bi ZHU Shan-Jiong SHEN Guan-Qiao YU National Laboratory of Plant molecular Genetics,institute of Plant Physiology and Ecology,Shanghai institutes for Biological sciences,Chinese Academy of sciences,Shanghai 200032,china National Laboratory of Plant molecular Genetics Institute of Plant Physiology and Ecology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Shanghai 200032 China

In prokaryotes,DNA supercoiling regulates the expression of many genes;for example,theexpression of Klebsiella pneumoniae nifLA operon depends on DNA negative supercoiling in anaerobicallygrown cells,which indicates that DNA supercoiling might play a role in gene regulation of the *** the expression of the nifH promoter in Sinorhizobium meliloti is not repressed by oxygen,itis proposed that the status of DNA supercoiling may not affect the expression of the nifH *** this hypothesis by analyzing nifH promoter activity in wild-type and gyr Escherichia coli in thepresence and absence of DNA gyrase *** results show that gene expression driven by the *** nifH promoter requires the presence of active DNA *** DNA gyrase increases thenumber of negative superhelical turns in DNA in the presence of ATP,our data indicate that negativesupercoiling is also important for nifH promoter *** study also shows that the DNA supercoiling-dependent *** nifH promoter activity is related to the trans-acting factors NtrC and NifA that *** supercoiling appeared to have a stronger effect on NtrC-activated nifH promoter activity than onNifA-activated promoter ***,these results from the *** nifH promoter model systemseem to indicate that,in addition to regulating gene expression during anaerobic signaling,DNA supercoilingmay also provide a favorable topology for trans-acting factor binding and promoter activation regardless ofoxygen status.

关键词： nifH DNA supercoiling gyrase Sinorhizobium meliloti gene expression

Characterization of a sodium-regulated glutaminase from cyanobacterium Synechocystis sp. PCC 6803

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Science china(Life sciences) 2008年第12期51卷 1066-1075页

作者： ZHOU Jie1, ZHOU JunXia1,2, YANG HaoMeng1, YAN ChengShi1 & HUANG Fang1 1 Key Laboratory of Photosynthesis and Environmental molecular Physiology, institute of Botany, Chinese Academy of sciences, Beijing 100093, china 2 Graduate School of Chinese Academy of sciences, Beijing 100039, china Key Laboratory of Photosynthesis and Environmental molecular Physiology Institute of Botany Chinese Academy of Sciences Beijing China Graduate School of Chinese Academy of sciences Beijing China

Glutaminase is widely distributed among microorganisms and mammals with important functions. Lit-tle is known regarding the biochemical properties and functions of the deamidating enzyme glutami-nase in cyanobacteria. In this study a putative glutaminase encoded by gene slr2079 in Synechocystis sp. PCC 6803 was investigated. The slr2079 was expressed as histidine-tagged fusion protein in Es-cherichia coli. The purified protein possessed glutaminase activity, validating the functional assign-ment of the genomic annotation. The apparent Km value of the recombinant protein for glutamine was 26.6 ± 0.9 mmol/L, which was comparable to that for some of other microbial glutaminases. Analysis of the purified protein revealed a two-fold increase in catalytic activity in the presence of 1 mol/L Na+. Moreover, the Km value was decreased to 12.2 ± 1.9 mmol/L in the presence of Na+. These data demon-strate that the recombinant protein Slr2079 is a glutaminase which is regulated by Na+ through in-creasing its affinity for substrate glutamine. The slr2079 gene was successfully disrupted in Synecho-cystis by targeted mutagenesis and the △slr2079 mutant strain was analyzed. No differences in cell growth and oxygen evolution rate were observed between △slr2079 and the wild type under standard growth conditions, demonstrating slr2079 is not essential in Synechocystis. Under high salt stress condition, however, △slr2079 cells grew 1.25-fold faster than wild-type cells. Moreover, the photosyn-thetic oxygen evolution rate of △slr2079 cells was higher than that of the wild-type. To further charac-terize this phenotype, a number of salt stress-related genes were analyzed by semi-quantitative RT-PCR. Expression of gdhB and prc was enhanced and expression of desD and guaA was repressed in △slr2079 compared to the wild type. In addition, expression of two key enzymes of ammonium assimi-lation in cyanobacteria, glutamine synthetase (GS) and glutamate synthase (GOGAT) was examined by semi-quant

关键词： cyanobacteria Synechocystis putative glutaminase enzyme activity mutagenesis salt tolerance

Multiparty quantum secret sharing of classical and quantum messages

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Progress in Natural Science:Materials International 2007年第1期17卷 26-31页

作者： CHEN Pan, DENG Fuguo and LONG Guilu ( Key Laboratory for Quantum Information and Measurements, and Department of Physics, Tsinghua University, Beijing 100084, china Key Laboratory of Beam Technology and Material Modification, MOE, institute of Low Energy Nuclear Physics, and Department of Material Science and Engineering, Beijing Normal University, Beijing 100875, china Beijing Radiation Center, Beijing 100875, china Key Laboratory for atomic and molecular Nano-sciences, Tsinghua University, Beijing 100084, china) Key Laboratory for Quantum Information and Measurements Department of Physics Tsinghua University Beijing 100084 China Key Laboratory of Beam Technology and Material Modification Beijing Normal University Beijing 100875 China institute of Low Energy Nuclear Physics Department of Material Science and Engineering Beijing Normal University Beijing 100875 China Beijing Radiation Center Beijing 100875 China Key Laboratory for atomic and molecular Nano-sciences Tsinghua University Beijing 100084 China

A scheme for multiparty quantum secret sharing of classical and quantum messages is proposed by using entanglement swapping. This scheme can distribute not only the classical information but also the quantum informati... 详细信息

关键词： quantum secret sharing classical message quantum message EPR pair.

Crosstalk between signaling pathways of adrenoreceptors and signal transducers and activators of transcription 3(STAT3)in heart

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Acta Pharmacologica sinica 2007年第2期28卷 153-161+163-165页

作者： Kai-zheng GONG Hui ZHANG Jian-hai DU You-yi ZHANG~2 institute of Vascular Medicine,Peking University Third Hospital,Key Laboratory of molecular Cardiovascular sciences,Ministry of Education Beijing 100083,china institute of Vascular Medicine Peking University Third Hospital Key Laboratory of Molecular Cardiovascular Sciences Ministry of Education Beijing China

Recently,there have been important advancements in our understanding of thesignaling mechanisms of adrenoreceptors(AR)and signal transducers and acti-vators of transcription 3(STAT3).While their crucial roles in the pathologicalprocesses of the heart are well established,accumulating evidence suggests thereis a complex pattern of crosstalk between these 2 signaling ***,the potential for crosstalk occurs at multiple levels in each signaling cascade andinvolves receptor transactivation,G proteins,small GTPases,cyclic adenosine 3’,5’-monophosphate/protein kinase A,protein kinase C,scaffold/adaptor proteins,protein tyrosine kinases,and mitogen-activated protein *** addition,post-translational modification(eg acetylation)of STAT3 may provide a link betweenSTAT3 and AR *** particular,crosstalk between these 2 systems in theheart would appear to be dependent upon the species/tissue studied,develop-mental stage,and eliciting *** at least partly accounts for the epige-netic effects on biological function that is mediated by the 2 signaling *** of these mechanisms will provide new targets in the development ofnovel clinical strategies for heart disorders.

关键词： receptors adrenergic signal transduction STAT3 transcription factor heart