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Theoretical study on S_1(~1B_(3u)) state electronic structure and absorption spectrum of pyrazine

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Science china Chemistry 2008年第12期51卷 1166-1173页

作者： HE RongXing1, ZHU ChaoYuan 2. CHIN Chih-Hao3 & LIN Sheng-Hsien2.3 1 College of Chemistry and Chemical Engineering, Southwest univer.ity, Chongqing 400715, china 2.Department of Applied Chemistry, Institute of {2. Science and center for Interdisciplinary {2. Science, National Chiao-Tung univer.ity, Hsinchu 300, china 3 Institute of atomic and {2. Sciences, Academia Sinica, Taipei 106, china 1. College of Chemistry and Chemical Engineering Southwest University Chongqing 400715 China 2. Department of Applied Chemistry Institute of Molecular Science and Center for Interdisciplinary Molecular Science National Chiao-Tung University Hsinchu 300 China 3. Institute of atomic and molecular Sciences Academia Sinica Taipei 106 China

Making use of a set of quantum chemistry methods, the harmonic potential surfaces of the ground state (S0(1Ag)) and the first (S1(1B3u)) excited state of pyrazine are investigated, and the electronic structures of the two states are characterized. In the present study, the conventional quantum mechanical method, taking account of the Born-Oppenheimer adiabatic approximation, is adopted to simulate the absorp-tion spectrum of S1(1B3u) state of pyrazine. The assignment of main vibronic transitions is made for S1(1B3u) state. It is found that the spectral profile is mainly described by the Franck-Condon progression of totally symmetric mode ν6a. For the five totally symmetric modes, the present calculations show that the frequency differences between the ground and the S1(1B3u) state are small. Therefore the displaced harmonic oscillator approximation along with Franck-Condon transition is used to simulate S1(1B3u) absorption spectra. The distortion effect due to the so-called quadratic coupling is demonstrated to be unimportant for the absorption spectrum, except the coupling mode ν10a. The calculated S1(1B3u) ab-sorption spectrum is in reasonable agreement with the experimental spectra.

关键词： pyrazine absorption spectrum quantum mechanical method electronic structure

Efficient degradation of dye pollutants using dioxygen mediated by iron(Ⅱ) 2.2.-bipyridine loaded layered clay catalyst under visible irradiation

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Science china Chemistry 2006年第5期49卷 407-410页

作者： CHENG Mingming1,SUN Zhenying1,2.MA Wanhong1,CHEN Chuncheng1,ZHAO Jincai1 & WANG Zhengping2.1. Laboratory of Photochemistry,center for molecular Science,Institute of Chemistry,Chinese Academy of Sciences,{2. 100080,china 2. Department of Chemical Engineering,Harbin Engineering univer.ity,Harbin 150001,china 1. Laboratory of Photochemistry Center for Molecular Science Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China 2. Department of Chemical Engineering Harbin Engineering University Harbin 150001 China

The organic-inorganic layered solid catalyst Fe(bpy)_3^(2.)-laponite was ableto photode-grade Rhodamine B (RhB) by activation of dioxygen under visible irradiation (λ > 42.nm), while the homogeneous aqueous solution Fe(bpy)_3^(2.) showed no photoactivity. The catalystcould be repeatedly used and retained its reactivity. The hybrid catalyst could be separated fromthe suspension by centrifugation or sedimentation. The TOC removal yield of RhB was *** oxygen species (ROS) formed during degradation was detected by EPR. A possible mechanismwas proposed on the basis of the experimental results.

关键词： laponite, Rhodamine B, molecular oxygen, visible light.

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双光子激发荧光各向异性度的成像

生物化学与生物物理进展 2005年第2期32卷 161-167页

作者：汪雪峰王毅蒋艳马辉清华大学物理系原子分子纳米科学教育部重点实验室北京中医药大学病理室清华大学深圳研究生院深圳518057

荧光各向异性度(fluorescence anisotropy) 测量可以获得荧光分子的转动速度信息,进而了解分子质量、结构、以及与周边环境的相互作用情况. 围绕一台双光子激发扫描荧光成像系统,通过改变外光路和图像记录与处理程序,从而实现了双光子... 详细信息

荧光各向异性度(fluorescence anisotropy) 测量可以获得荧光分子的转动速度信息,进而了解分子质量、结构、以及与周边环境的相互作用情况. 围绕一台双光子激发扫描荧光成像系统,通过改变外光路和图像记录与处理程序,从而实现了双光子激发荧光各向异性度成像,并针对一些典型样品和体系,展示了该方法的应用. 实验中观察了FITC荧光分子、FITC结合的CD44抗体分子及与肿瘤细胞表面受体结合的FITC-CD44抗体分子. 测量结果表明,不同分子质量、不同微观环境状态下的荧光分子,其各向异性度大小不同,在各向异性度图中能够被明显区分. 荧光各向异性度成像能够定量测量样品微区的各向异性度值,并以二维图像的形式直观表达,是各向异性度测量与成像技术的良好结合.

关键词：荧光各向异性度双光子扫描成像细胞膜流动性小檗碱肿瘤细胞

Modeling the intracellular dynamics for Vif-APO mediated HIV-1 virus infection

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Chinese Science Bulletin 2010年第22期55卷 2329-2340页

作者： WANG Yi1,2.& LAI LuHua1,3 1 center for Theoretical Biology, Peking univer.ity, {2. 100871, china 2.School of Physics, Peking univer.ity, {2. 100871, china 3 BNLMS, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and molecular Engineering, Peking univer.ity, {2. 100871, china center for Theoretical Biology Peking University Beijing 100871 China School of Physics Peking University Beijing 100871 China BNLMS State Key Laboratory for Structural Chemistry of Unstable and Stable Species College of Chemistry and Molecular Engineering Peking University Beijing 100871 China

The viral infectivity factor (Vif) was found to be essential for controlling HIV-1 virus infectivity. It targets cellular antiviral proteins in APOBEC family (APO) to trigger its fast degradation and inhibits APO packaging into nascent virion. In the present study, we propose a mathematical model to quantitatively study the intracellular dynamics of these typical virus-host interactions. Four sets of published experimental data were compared with simulation results to justify the model. Systematic parameter sensitivity and perturbation analysis showed that parameters related to APO are crucial to the infectivity of newly synthesized HIV-1 virus. Interestingly, we discovered that the synthesis rate of the viral structure protein Gag and the required number per nascent virion are optimized to achieve high virion production with minimal level of packaged APO, and large portion of model parameters are beneficial to virus only within a relatively small range. Furthermore, minor variations in several parameters related to viral protein Tat, the activator of viral RNA synthesis, were found to induce switch-like behaviors on both incorporated Vif and APO. These findings may provide new insights for understanding the high mutation rate of HIV-1 virus and its latency, as well as help identify key targets for therapeutic design.

关键词：病毒感染载脂蛋白 HIV 细胞内动力学抗病毒蛋白建模介导

SOLID PHASE TRANSITION OF SYNDIOTACTIC POLYSTYRENE IN SUPERCRITICAL CO_2

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Chinese Journal of Polymer Science 2002年第3期20卷 191-196页

作者： Yu-ying Li Jia-song He State Key Laboratory of Engineering Plastics, center for molecular Science, Institute of Chemistry Chinese Academy of Sciences, {2. 100080 china Chinese Acad Sci Inst Chem Ctr Mol Sci State Key Lab Engn Plast Beijing 100080 Peoples R China

Solid phase transition of the a form crystals to the 3 form crystals in syndiotactic polystyrene (sPS) samples has occurred in supercritical CO2. This transformation is different from those detected under other conditions. The effects of some factors (e.g. time, temperature, and pressure) on the solid phase transformation of sPS in supercritical CO2.were analyzed in detail. Experimental results show that longer time, higher temperature or higher pressure favors the transformation of the a form crystals to the beta form crystals.

关键词： solid phase transition syndiotactic polystyrene supercritical CO2

Expression of two insect-resistant genes cryIA (b&c)/GNA in transgenic tobacco plants results in added protection against both cotton bollworm and aphids

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Chinese Science Bulletin 1999年第22期44卷 2051-2058页

作者： WANG Zhibin and QUO SanduiLaboratory of Biochemistry and molecular Biology , Biotechnology Research center, Chinese Academy of Agricultural Sciences , {2. 100081, china Laboratory of Biochemistry and molecular Biology Biotechnology Research Center Chinese Academy of Agricultural Sciences Beijing China

The synthesized Bacillus thuringiensis insecticidal protein gene crylA(b&c) and the synthesized gene GNA, (the mannose specific lectin from snowdrop ( Galanthus nivalis)), tumefaciens have been inserted into plant expression vector pGW4BAI. Leave stripes of Nico-tiana tabacum var. K32. have been transformed with Agrobacterium tumefaciens strain LBA4404 harboring the plant expression vector. 2. kanamycin resistant tobacco plants

关键词： crylA(b&c) snowdrop lectin insect-resistance transgenic plants cotton bollworm aphids pyramiding.

Status of study on biological and toxicological effects of nanoscale materials

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Science china Chemistry 2005年第5期48卷 385-394页

作者： WANG Bing1, FENG Weiyue1, ZHAO Yuliang1, XING Gengmei1, CHAI Zhifang1, WANG Haifang2.& JIA Guang3 1. Laboratory for Bio-Environmental Health Sciences of Nanoscale Materials (Nanosafety Lab), Institute of High Energy Physics, Chi-nese Academy of Sciences, beijing 100049, china 2. College of Chemistry and {2. Engineering, Peking univer.ity, beijing 100871, china 3. Department of Occupational and Environmental Health Sciences, School of Public Health, Peking univer.ity, beijing 100083, china 1. Laboratory for Bio-Environmental Health Sciences of Nanoscale Materials (Nanosafety Lab) Institute of High Energy Physics Chinese Academy of Sciences 100049 Beijing China 2. College of Chemistry and molecular Engineering Peking University 100871 Beijing China 3. Department of Occupational and Environmental Health Sciences School of Public Health Peking University 100083 Beijing China

Because the physical and chemical properties of nanosized materials mostly differ from the existing microsized materials, their potential impacts on human health and the envi-ronment will be topics under the serious discussions in press and in a number of international scientific journals. We analyze and summarize the existing data of the experimental study on the biological activities and adverse effects of nanoscale materials/particles including single wall carbon nanotubes, multi wall carbon nanotubes, titanium oxide and iron powders. Though some biological behaviors of nanoscale materials observed cannot be understood on the basis of the current knowledge, as the existing data are mostly preliminary, it is too early to make some ex-clusive conclusions on biological activities (or the toxicity) of any of nanoscale materials. The experimental techniques, the current topics, and the future research directions for this new re-search field are also discussed.

关键词： nanomaterials, single wall carbon nanotubes, multi wall carbon nanotubes, titanium oxide and iron, biological activity and toxicological effect.

Microstructure and Mechanical Properties of Heat-treated GeSb_2.e_4 Thin Films

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Journal of Wuhan univer.ity of Technology(Materials Science) 2007年第2期22卷 196-200页

作者：丁建宁解国新 Micro/Nano Science & Technology center Jiangsu University State Key Laboratory of Tribology Tsinghua University

The effect of annealing on microstructure, adhesive and frictional properties of GeSb2.e4 films were experimentally studied. The GeSb2.e4 films were prepared by radio frequency （RF） magnetron sputtering, and annealed at 2.0℃ and 340℃ under vacuum circumstance, respectively. The adhesion and friction experiments were mainly conducted with a lateral force microscope （LFM） for the GeSb2.e4 thin films before and after annealing. Their morphology and phase structure were analyzed by using atomic force microscopy （AFM） and X-ray Diffraction （XRD） techniques, and the nanoindention was employed to evaluate their hardness values. Moreover, an electric force microscope （EFM） was used to measure the surface potential. It is found that the deposited GeSb2.e4 thin film undergoes an amorphous-to-fcc and fcc-to-hex structure transition; the adhesion has a weaker dependence on the surface roughness, but a certain correlation with the surface potential of GeSb2.e4 thin films. And the friction behavior of GeSb2.e4 thin films follows their adhesion behavior under a lower applied load. However, such a relation is replaced by the mechanical behavior when the load is relatively higher. Moreover, the GeSb2.e4 thin film annealed at 340℃ presents a lubricative property.

关键词： GeSb2.e4 films annealing microstructure mechanical properties friction

MB_8^(2.) (M=Be,Mg,Ca,Sr,and Ba):Planar octacoordinate alkaline earth metal atoms enclosed by boron rings

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Science china Chemistry 2010年第8期53卷 1737-1745,1829-1832页

作者： PU ZhiFeng1,GE MaoFa1 & LI QianShu2.1State Key Laboratory for Structural Chemistry of Unstable and Stable Species beijing National Laboratory for molecular Sciences (BNLMS) Institute of Chemistry,Chinese Academy of Sciences,beijing 100190,china 2.4} for Computational Quantum Chemistry,South china Normal univer.ity,Guangzhou 510631,china 1. State Key Laboratory for Structural Chemistry of Unstable and Stable Species beijing National Laboratory for molecular Sciences (BNLMS) Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China2. Center for Computational Quantum Chemistry South China Normal University Guangzhou 510631 China

Complexes involving planar octacoordinate alkaline earth metal atoms in the centers of eight-membered boron rings have been investigated by two density functional theory (DFT) ***82.with D8h symmetry is predicted to be stable,both geometrically and electronically,since a good match is achieved between the size of the central beryllium atom and the eight-membered boron *** contrast,the other alkaline earth metal atoms cannot be stabilized in the center of a planar eight-membered boron ring because of their large *** following the out-of-plane imaginary vibrational frequency,pyramidal C8v MgB82.,CaB82.,SrB82.,and BaB82.structures are *** presence of delocalized π and σ valence molecular orbitals in D8h BeB82.gives rise to aromaticity,which is reflected by the value of the nucleus-independent chemical *** D8h BeB82.structure is confirmed to be the global minimum on the potential energy surface.

关键词： density functional theory octacoordinate alkaline earth metal aromatic molecular orbital