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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 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 College of Chemistry and Chemical Engineering Southwest University Chongqing China Department of Applied Chemistry Institute of Molecular Science and Center for Interdisciplinary Molecular Science National Chiao-Tung University Hsinchu China institute of Atomic and molecular Sciences Academia Sinica Taipei 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

VISCOELASTIC BEHAVIOR OF THE NON-HOOKE DEFORMATION BEFORE YIELDING IN UNIAXIAL DRAWING OF AMORPHOUS POLY(ETHYLENE TEREPHTHALATE)

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Chinese Journal of Polymer Science 2001年第4期19卷 399-405页

作者： Zhen-hua Yuan De-yan Shen Ren-yuan Qian Polymer Physics Laboratory 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及化学国家重点实验室北京

Viscoelastic behavior of the non-Hooke deformation of amorphous PET film before yield was investigated in the temperature region 74-80.5 degreesC around the glass transition temperature. The film specimen was drawn to yield point followed by unloading to zero stress, then the residual deformation was held constant; while the subsequent evolution of the stress was recorded. An induction period was found in the course of stress evolution followed by a stress step-increase. The induction period decreases with increasing drawing temperature with an activation energy of 1.10 MJ/mol.K, which is attributed to the time needed for the relaxation of rubbery deformation through cooperative internal rotations. At temperatures lower than 74 degreesC, there is no stress increase or the induction period becomes too long to be observed. Thus the nature of anelasticity in the non-Hooke region before yielding is attributed to stress induced rubbery deformation. The experimental results are interpreted in terms of Perez' theological model of a series connected Hooks spring and a Voigt element consisting of a parallel connected elastic spring and a dashpot.

关键词： pre-yield deformation PET uniaxial drawing non-Hooke deformation viscoelasticity stress induced rubbery deformation

Genomic organization and sequence analysis of the vomeronasal receptor V2R genes in mouse genome

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Chinese Science Bulletin 2007年第3期52卷 336-342页

作者： YANG Hui1,2 & Zhang YaPing1,3 1 Laboratory of cellular and molecular Evolution, Kunming institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China 2 Graduate University of the Chinese Academy of Sciences, Beijing 100049, China 3 Laboratory for Conservation and Utilization of Bio-resources, Yunnan University, Kunming 650091, China Laboratory of cellular and molecular Evolution Kunming Institute of Zoology Chinese Academy of Sciences Kunming China Graduate University of the Chinese Academy of Sciences Beijing China Laboratory for Conservation and Utilization of Bio-resources Yunnan University Kunming China

Two multigene superfamilies, named V1R and V2R, encoding seven-transmembrane-domain G-protein coupled receptors (GPCRs) have been identified as pheromone receptors in mammals. Three V2R gene families have been described in mouse and rat. Here we screened the updated mouse genome se- quence database and finally retrieved 63 putative functional V2R genes including three newly identified genes which formed a new additional family. We described the genomic organization of these genes and also characterized the conservation of mouse V2R protein sequences. These genomic and se- quence information we described are useful as part of the evidence to speculate the functional domain of V2Rs and should give aid to the functionality study in the future.

关键词：大白鼠基因组犁鼻受体2 多基因超家族序列分析

Key Conditions in Capillary Electrophoresis of Amino Acids with Indirect Ultraviolet Detection

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Chinese Chemical Letters 2000年第9期11卷 803-806页

作者： Zhi Xin WANG Yi CHEN Qing GUO Center for molecular Science. institute of Chemistry. The Chincse Academy of Sciences. Beijing 100080 Center for molecular Science Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China

Key factors for capillary electrophoresis of amino acids with indirect ultraviolet detection were illustrated. Buffer compositions and additives were found to be influential as expected, while buffer pH was shown to be particularly critical to the separation and detection. The effect of pH also depended on the electrophoretic mode used. Ways to obtain recurring and selective were suggested.

关键词： amino acids capillary electrophoresis indirect ultraviolet detection

Synthesis and Stereostructure of New β-Lactam Derivatives of1,5-Benzothiazepines

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Chinese Chemical Letters 1999年第6期10卷 447-448页

作者： Yuan LI Na SUN Sheng JIN(Department of Chemistry Hebei University Shijiazhuang 050016 institute of Chemistry and molecular Engineering Peking University Beijing 100871) Department of Chemistry Hebei Normal University Shijiazhuang 050016 China Inst. of Chem. and Molec. Eng. Peking University Beijing 100871 China

Reaction of 1,5-benzothiazepine with N-protected glycine gives new a-amino-β-lactamderivatives of 1.5-benzothiazepine. The configuration and conformation of the products wereconfirmed by x-ray diffraction. The resu... 详细信息

关键词： 1.5-Benzothiazepine β-lactam stereospecific reaction

Stereocomplex Formation of Atactic Poly(methyl mcthacrylate)

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Chinese Chemical Letters 2000年第5期11卷 405-406页

作者： Qun GU De Yan SHEN (Polymer Physics Laboratory, Center for molecular Science, institute of Chemistry, Chinese Academy of Sciences, Bet.jing 100080) Polymer Physics Laboratory Center for Molecular Science Chinese Academy of Sciences Beijing 100080 China

Stereocomplexes formed in atactic poly(methyl methacrylatc) (α-PMMA) films cast form different solvents were studied by means of Fourier transform infrared spectroscopy (FTIR). and differential scanning calorimetry (... 详细信息

关键词： Atactic poly(methyl methacrylate) stereocomplex annealing.

Applying a highly specific and reproducible cDNA RDA method to clone garlic up-regulated genes in human gastric cancer cells

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World Journal of Gastroenterology 2002年第2期8卷 213-216页

作者： Yong Li You-Yong Lu,Beijing institute for Cancer Research,Beijing Laboratory of molecular Oncology,School of Oncology,Peking University,Beijing 100034,China Beijing institute for Cancer Research Beijing Laboratory of Molecular Oncology School of Oncology Peking University 1 Da-Hong-Luo-Chang Street Western District Beijing 100034 China.

AIM: To develop and optimize cDNA representational difference analysis (cDNA RDA) method and to identify and clone garlic up-regulated genes in human gastric cancer (HGC) cells. METHODS: We performed cDNA RDA method by using abundant double-stranded cDNA messages provided by two self-constructed cDNA libraries (Allitridi-treated and paternal HGC cell line BGC823 cells cDNA libraries respectively). Bam H I and Xho I restriction sites harbored in the library vector were used to select representations. Northern and Slot blots analyses were employed to identify the obtained difference products. RESULTS: Fragments released from the cDNA library vector after restriction endonuclease digestion acted as good marker indicating the appropriate digestion degree for library DNA. Two novel expressed sequence tags (ESTs) and a recombinant gene were obtained. Slot blots result showed a 8-fold increase of glia-derived nexin/protease nexin 1 (GDN/PN1) gene expression level and 4-fold increase of hepatitis B virus x-interacting protein (XIP) mRNA level in BGC823 cells after Allitridi treatment for 72h. CONCLUSION: Elevated levels of GDN/PN1 and XIP mRNAs induced by Allitridi provide valuable molecular evidence for elucidating the garlic's efficacies against neurodegenerative and inflammatory diseases. Isolation of a recombinant gene and two novel ESTs further show cDNA RDA based on cDNA libraries to be a powerful method with high specificity and reproducibility in cloning differentially expressed genes.

关键词： Gene Expression Regulation, Neoplastic Sequence Analysis, DNA Allyl Compounds Amyloid beta-Protein Precursor Base Sequence Carrier Proteins Cloning, molecular Expressed Sequence Tags Garlic Gene Library Humans molecular Sequence Data Plasminogen Inactivators Platelet Aggregation Inhibitors Receptors, Cell Surface Research Support, Non-U.S. Gov't Stomach Neoplasms Sulfides Tumor Cells, Cultured Viral Nonstructural Proteins

Expressional Analysis of an EREBP Transcription Factor Gene OsEBP-89 in Rice

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Acta Biochimica et Biophysica Sinica 2004年第1期36卷 21-26页

作者： Hui SHEN and Zong-Yang WANG( The State Key Laboratory of Plant molecular Genetics, institute of Plant Physiology & Ecology, Shanghai institutes for Biological Sciences,the Chinese Academy of Sciences, Shanghai 200032, China ) The State Key Laboratory of Plant molecular Genetics Institute of Plant Physiology & Ecology Shanghai Institutes for Biological Sciences the Chinese Academy of Sciences Shanghai 200032 China

OsEBP-89 gene encodes an ethylene responsive element binding protein (EREBP) transcription factor from rice (Oryza sativa). Northern blot analysis revealed that OsEBP-89 was expressed in root, stem, seeds, flowers and leaves. Histochemical assay showed that β-glucuronidase (GUS) was expressed mainly in phloem of vascular tissues of the root and stem transition region (RST), basal part of sheath roots, stem node and basal part of adventitious roots, also in endosperm of seeds in transgenic rice harboring OsEBP-89/GUS construct (pNSG). A sequence region from -279 to -97 was found to play an important role for OsEBP-89 gene expression through promoter deletion assay. The possible function of OsEBP-89 gene was discussed.

关键词： OsEBP-89 gene rice EREBP subfamily transcription factor tissue expression

New feature extraction in gene expression data for tumor classification

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Progress in Natural Science:Materials International 2005年第9期15卷 861-864页

作者： HE Renya, CHENG Qiansheng**, WU Lianwen and YUAN Kehong(LMAM, School of Mathematical Sciences, institute of molecular Medicine, Peking University, Beijing 100871, China) LMAM School of Mathematical Sciences Institute of Molecular Medicine Peking University Beijing 100871 China

Using gene expression data to discriminate tumor from the normal ones is a powerful method. However, it is sometimes difficult because the gene expression data are in high dimension and the object number of the data sets is very small. The key technique is to find a new gene expression profiling that can provide understanding and insight into tumor related cellular processes. In this paper, we propose a new feature extraction method based on variance to the center of the class and employ the support vector machine to recognize the gene data either normal or tumor. Two tumor data sets are used to demonstrate the effectiveness of our methods. The results show that the performance has been significantly improved.

关键词： Bioinformatics Feature extraction Gene expression Support vector machine (SVM) Tumor classification