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Transient species and its properties of melatonin

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Science china Chemistry 2006年第4期49卷 308-314页

作者： ZHU Hongping1,2. ZHANG Zhaoxia1,2. ZHAO Hongwei1, WANG Wenfeng1 & YAO Side1 1. shanghai institute of {2. Physics, chinese academy of sciences, shanghai 2.1800, china 2. Graduate University of the chinese academy of sciences, Beijing 100049, china 1. shanghai institute of {2. Physics Chinese Academy of Sciences Shanghai 201800 China 2. Graduate University of the chinese academy of sciences Beijing 100049 China

The photo-physical and photo-chemical properties of melatonin (ML) werestudied by 2.6 nm laser flash photolysis (LFP). ML undergoes photo-ionization to produce radicalcation of ML (ML^(·+))and hydrated electrons (e_(aq)^-), while excited triplet state ~3ML~* is alsoformed during photolysis. The oxidation via one electron transfer from ML to SO_4^(·+) and thetriplet state of riboflavin (~3RF~*) has been also investigated and the rate constants for theprocess have been determined to be 8.0x10^9 and 1.4x10^9 L·mol^(-1)·s^(-1) respectively. Theradical cation of 2.2.'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS^(·+)) scavengingcapacities of melatonin and other antioxidants are compared in this paper.

关键词： melatonin, laser flash photolysis, photoionization, triplet state.

Structural and microstructural transformations in Bi_2.r_2.a_(1-x)Y_xCu_2._(8+y) system

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chinese Science Bulletin 1997年第3期42卷 192-196页

作者： SONG Chengyu, WEN Shulin and CHE Guangcan1. shanghai institute of Ceramics,{2., shanghai 2.0050, china 2. State Key Laboratory of Supercon-ductivity, institute of Physics,{2., Beijing 100080, china shanghai institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China

SINCE the discovery of high-Tc superconductors, experiments have revealed that the phase diagrams of La2.xSrxCuO4 and YBa2.u3O6+x resemble each other. The antiferromagnetic phase is commonly situated in the vicinity o... 详细信息

SINCE the discovery of high-Tc superconductors, experiments have revealed that the phase diagrams of La2.xSrxCuO4 and YBa2./sub>Cu3O6+x resemble each other. The antiferromagnetic phase is commonly situated in the vicinity of the superconductive phase. In Bi-2.12.sys-

关键词： Bi2.r2.a1-xYxCu2.y substitution structural transformation.

Monte Carlo calculation method on low energy electronscattering in polybasic medium

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chinese Science Bulletin 1998年第2期43卷 171-174页

作者： TAN Zhenyu 1 and HE Yancai 2.1. College of Electric Power, Shandong University of Technology, Jinan 2.0061, china 2. shanghai {2. of Ceramics, chinese academy of sciences, shanghai 2.0050, china College of Electric Power Shandong University of Technology Jinan China shanghai institute of Ceramics Chinese Academy of Sciences Shanghai China

A novel Monte Carlo method of simulating low energy electron (LEE) scattering in polybasic medium is presented. The Mott cross section is adopted to describe the elastic scattering of LEE, and a mean cross section idea is proposed instead of usual determination of the scattering center. The Joy’’s modified Bethe equation is used to calculate energy loss of LEE. The scattering processes of LEE in bulk PMMA have been simulated. And the electron backscattering coefficients, the electron interaction range and energy dissipation distribution of LEE in bulk PMMA have been calculated and compared with those calculated by the method of determining scattering center.

关键词： low_energy electron scattering Monte Carlo method cross_section.

Cytotoxicity of carbon nanotubes

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Science china Chemistry 2008年第11期51卷 1021-1029页

作者： ZHU Ying1,2.& LI WenXin1 1 Laboratory of Nano-biology and Medicine, shanghai institute of {2. Physics, chinese academy of sciences, shanghai 2.1800, china 2.Graduate School of chinese academy of sciences, Beijing 100049, china 1. Laboratory of Nano-biology and Medicine Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 China 2. Graduate School of chinese academy of sciences Beijing 100049 China

With large-scale production and application at large scale, carbon nanotubes (CNTs) may cause ad-verse response to the environment and human health. Thus, study on bio-effects and safety of CNTs has attracted great attention from scientists and governments worldwide. This report briefly summa-rizes the main results from the in vitro toxicity study of CNTs. The emphasis is placed on the descrip-tion of a variety of factors affecting CNTs cytotoxicity, including species of CNTs, impurities contained, lengths of CNTs, aspect ratios, chemical modification, and assaying methods of cytotoxicity. However, experimental information obtained thus far on CNTs' cytotoxicity is lacking in comparability, and some-times there is controversy about it. In order to assess more accurately the potential risks of CNTs to human health, we suggest that care should be taken for issues such as chemical modification and quantitative characterization of CNTs in cytotoxicity assessment. More importantly, studies on physical and chemical mechanisms of CNTs' cytotoxicity should be strengthened; assaying methods and evaluating criteria characterized by nanotoxicology should be gradually established.

关键词： carbon nanotubes (CNTs) cell bio-security

A pulse radiolysis study on electron affinity of piperonal

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Science china Chemistry 2005年第5期48卷 476-480页

作者： MA Jianhua1, LIN Weizhen2. WANG Wenfeng2.& YAO Side2.1. College of Biology Engineering, Jimei University, Xiamen 36102., china 2. shanghai {2. of applied Physics, chinese academy of sciences, shanghai 2.1800, china 1. College of Biology Engineering Jimei University 361021 Xiamen China 2. shanghai institute of {2. Physics Chinese Academy of Sciences 201800 Shanghai China

The piperonal electron affinity was studied using pulse radiolysis technique. The electron transfer reaction process between piperonal and anthraquinone-2.sulfate was observed in the pH 7 phosphoric acid salt buffer. The transient absorption spectra of electron transfer re-action between piperonal and anthraquinone-2.sulfate were obtained, and the initial proof of the electron transfer between electron donor and acceptor was provided directly. The one-electron reduction potential of piperonal was determined to be ?0.457 V.

关键词： piperonal, pulse radiolysis, one-electron reduction potential.

Serine racemase expression in mouse cerebral cortex after permanent focal cerebral ischemia

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Acta Pharmacologica Sinica 2004年第4期25卷 38-43页

作者： Li-zhenWANG, Xing-zu ZHU2.Department of Pharmacology, shanghai institute of Materia Medica, shanghai institutes for Biological sciences, chinese academy of sciences, shanghai 2.12.3, china Department of Pharmacology Shanghai Institute of Materia MedicaShanghai Institutes for Biological Sciences Chinese Academy of Sciences

AIM: To study the alterations of the expressions of serine racemase in C57BL/6 mouse brain after permanent focal cerebral ischemia. METHODS: The mRNA level and the protein level of serine racemase were assayed by semiquantitative reverse transcription polymerase chain reaction (RT-PCR) and Western blot, respectively. The amount of D-serine and L-serine were measured by HPLC. RESULTS: High levels of serine racemase were constitutively expressed in the normal cortex of mouse. At early stage after middle cerebral artery occlusion (MCAO), no significant change in expression of serine racemase was observed in temporoparietal cortex in ipsila- teral hemisphere. However, delayed transient decreases of serine racemase in both mRNA and protein levels were detected from d 6 to d 10 after ischemia. Correspondingly, D-serine concentration also declined in the ipsilateral cortex during this period when compared with the D-serine level in the contralateral cortex. CONCLUSION: Delayed decreases in serine racemase expression and D-serine level occurred in the temporoparietal cortex at the late stage after focal cerebral ischemia.

关键词： D-serine L-serine serine racemase inbred C57BL mice brain ischemia

Boundary element-free method for elastodynamics

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Science china(Physics,Mechanics & Astronomy) 2005年第6期48卷 641-657页

作者： CHENG Yumin1 & PENG Miaojuan2.1. shanghai institute of {2. Mathematics and Mechanics, shanghai University, shanghai 2.0072. china 2. Department of Civil Engineering, shanghai University, shanghai 2.0072. china 1. shanghai institute of {2. Mathematics and Mechanics Shanghai University 200072 Shanghai China 2. Department of Civil Engineering Shanghai University 200072 Shanghai China

The moving least-square approximation is discussed first. Sometimes the method can form an ill-conditioned equation system, and thus the solution cannot be obtained correctly. A Hilbert space is presented on which an orthogonal function system mixed a weight function is defined. Next the improved moving least-square approximation is discussed in detail. The improved method has higher computational efficiency and precision than the old method, and cannot form an ill-conditioned equation system. A boundary element-free method (BEFM) for elastodynamics problems is presented by combining the boundary integral equation method for elastodynamics and the improved moving least-square approximation. The boundary element-free method is a meshless method of boundary integral equation and is a direct numerical method compared with others, in which the basic unknowns are the real solutions of the nodal variables and the boundary conditions can be applied easily. The boundary element-free method has a higher computational efficiency and precision. In addition, the numerical procedure of the boundary element-free method for elastodynamics problems is presented in this paper. Finally, some numerical examples are given.

关键词： moving least-square approximation, improved moving least-square approximation, elastodynamics, boundary integral equation, meshless method, boundary element-free method, Fourier eigen transform.

Sequence analysis of mRNA polyadenylation signals of rice genes

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chinese Science Bulletin 2006年第9期51卷 1069-1077页

作者： LU Ying1, 2. GAO Chenxi1,2.3 & HAN Bin1,3,41. National Center for Gene Research, shanghai institutes for Biological {2., chinese academy of sciences, shanghai 2.02.3, china 2. Graduate School of the chinese academy of sciences, Beijing 100039, china 3. institute of Plant Physiology and Ecology, shanghai institutes for Biological {2., chinese academy of sciences, shanghai 2.0032. china National Center for Gene Research Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Shanghai 200233 China Graduate School of the chinese academy of sciences Beijing 100039 China institute of Plant Physiology and Ecology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Shanghai 200032 China

The formation of eukaryotic mRNAs involves the cleavage and polyadenylation of pre- mRNAs. To investigate the sequence requirement of putative polyadenylation signals (PASs), poly(A) sites and downstream elements (DUEs) in 3′-end-pro- cessing in rice, we compared expressed sequences tags (ESTs) with poly(A) extremity to full-length cDNA sequences and constructed a database of 12.69 pre- mRNA sequences in ?40―+40 nt surrounding the poly(A) sites, which were from 9953 genes. The al- ternative poly(A) sites were revealed in approxi- mately 2.% of mRNAs. Nearly 80% of pre-mRNAs showed stringent requirement of the YA (CA or UA) at poly (A) sites for polyadenylation. About 7.9% had the AAUAAA signals on ?40―?1 nt upstream of the poly(A) sites. Over 60% of mRNAs probably used the one- or two-base variants of AAUAAA hexamers as their PASs in 3′ fragments. The single-base variants of AAUGAA revealed the high frequency in 11.5% of 3′ fragments. The DUEs were detected in 90% of pre- mRNAs, especially more than half of the pre-mRNAs with multi-base variants of AAUAAA had the DUEs surrounding the poly(A) site. The location of DUE is also important for defining the cleavage site. Al- though most of the rice pre-mRNAs did not contain AAUAAA signal, the existence of downstream ele- ments ensured the efficiency of cleavage-polyade-

关键词：多聚腺苷酸序列分析 mRNA 水稻基因工程

Tissue Distribution and Purification of Prophenoloxidase in Larvae of Asian Corn Borer, Ostrinia furnacalis Guenée (Lepidoptera: Pyralidae)

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Acta Biochimica et Biophysica Sinica 2004年第5期36卷 360-364页

作者： Cong-Jing FENG1,2.and Wen-Jun FU1* 1institute of Plant Physiology and Ecology, shanghai institute for Biological sciences, the chinese academy of sciences, shanghai 2.002., china 2.he GraduateSchool of the chinese academy of sciences, Beijing 100039, china institute of Plant Physiology and Ecology Shanghai Institute for Biological Sciences the Chinese Academy of Sciences The Graduate School of the chinese academy of sciences

Using ammonium sulphate precipitation, Blue-Sepharose CL-6B, Phenyl-Sepharose CL-4B, prophenoloxidase (PPO) was isolated and purified from hemolymph of Ostrinia furnacalis larvae. This zy- mogen was a heterodimer, and composed of two subunits with the relative molecular mass ranging from 66.2. kD to 97.4 kD determined by SDS-PAGE. Western blotting and indirect immunofluorescence test showed that PPO was present in integument, hemolymph plasma and cell membrane of granular hemocytes and oenocytoids of O. furnacalis larvae.

关键词： Ostrinia furnacalis prophenoloxidase tissue distribution purification