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Azomethine ylide-formation from N-phthaloylglycine by photoinduced decarboxylation:A theoretical study

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中国科学:化学 2012年第10期42卷 1499-1500页

作者： FANG Qiu,DING LiNa & FANG WeiHai* college of Chemistry,beijing normal university,beijing 100875,china college of Chemistry beijing normal university beijing 100875 china

In this work,we report the first CASPT2//CASSCF study of the mechanism of the photodecarboxylation of *** charge transfer excited state SCT(1ππ*) is initially populated upon irradiation at 266 *** a result of a fast internal conversion to the lowest excited singlet state SCT-N(1ππ*),this state becomes a favorable precursor state for proton transfer,which triggers ***,the excited state intramolecular proton transfer(ESIPT) and decarboxylation processes proceed in an asynchronous concerted *** ESIPT process is accomplished in the SCT-N(1ππ*) state,but the CO2 molecule is finally formed in the ground state via the SCT/S0 conical *** ylide is formed in the ground state as a complex with CO2.A barrier of ～15 kcal/mol indicates that azomethine ylide is stable in the ground state,which is consistent with the experimental *** work provides mechanistic details about the formation of azomethine ylide by photoreaction of N-phthaloylglycine.

关键词： N-phthaloylglycine photodecarboxylation excited state intramolecular proton transfer CASPT2//CASSCF method

Evidence from carbon isotope measurements for biological origins of individual long-chain n-alkanes in sediments from the Nansha Sea,china

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Chinese Science Bulletin 2002年第7期47卷 578-581页

作者： DUAN Yi & WANG ZhipingState Key Laboratory of Gas Geochemistry, Lanzhou Institute of Geology, Chinese Academy of sciences, Lanzhou 730000, china Institute of environmental Science, beijing normal university, beijing 100875, china State Key Laboratory of Gas Geochemistry Lanzhou Institute of Geology Chinese Academy of Sciences Lanzhou China Institute of environmental Science Beijing Normal University Beijing China

Carbon isotopes are measured for individual long-chain n-alkanes in sediments from the Nansha Sea. The features of carbon isotopic compositions of individual n-alkanes and their origins are studied. The results show that the long-chain n-alkanes have a light carbon isotopic composition and a genetic feature of mixing sources, and low-latitude higher plants and microbes are considered to be their main end member sources. Based on the abundances and carbon isotopic compositions of individual n-alkanes, the fractional contributions of the two end member sources to individual n-alkanes are quantitatively calculated by using a mixing model. The obtained data indicate that the fractional contributions of the two biological sources are different in the three samples. A trend is that the contribution of microbes increases with the depth. These results provide the theory basis and quantitatively studied method for carbon isotopic applied research of individual n-alkanes.

关键词： modern marine sediment individual n-alkane carbon isotopic composition biological source.

Two-dimensional line thermal

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Communications in Nonlinear Science and Numerical Simulation 2000年第3期5卷 91-97页

作者： G. Q. CHEN and J. H. W. LEE(a) Centre for environmental sciences / State Key Laboratory for Thrbulence Research, Peking university, beijing 100871 b)Institute of environmental sciences, beijing normal university, beijing 100875 e-mail: gqchen@ns.nlspku. a Centre for environmental sciences / State Key Laboratory for Turbulence Research Peking University Beijing 100871 China Institute of environmental sciences Beijing Normal University Beijing 100875 China

The time evolution of a two-dimensional line thermal - a turbulent flow produced by an initial element with significant buoyancy released in a large water body, is numerically studied using the two-equation k-e model ... 详细信息

关键词： thermal and plume environmental fluid mechanics

Quenched moderate deviations principle for random walk in random environment

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Science china Mathematics 2010年第8期53卷 1947-1956页

作者： HONG WenMing 1 & WANG HuaMing 1,2 1 Key Laboratory of Mathematics and Complex Systems of Ministry of Education & School of Mathematical sciences,beijing normal university,beijing 100875,china 2 Department of Basic Courses,Business college,beijing Union university,beijing 100025,china Key Laboratory of Mathematics and Complex Systems of Ministry of Education & School of Mathematical sciences Beijing Normal University Beijing China Department of Basic Courses Business College Beijing Union University Beijing China

We derive a quenched moderate deviations principle for the one-dimensional nearest random walk in random environment,where the environment is assumed to be stationary and *** approach is based on hitting time decompos... 详细信息

关键词： random walk in random environment moderate deviations principle hitting time

APPLICATION OF SWAT MODEL IN THE UPSTREAM WATERSHED OF THE LUOHE RIVER

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Chinese Geographical Science 2003年第4期13卷 334-339页

作者： ZHANG Xue-song, HAO Fang-hua, CHENG Hong-guang, LI Dao-feng (State Key Laboratory of Water Environment Simulation,Institute of environmental sciences, beijing normal university,beijing 100875,P. R. china) State Key Laboratory of Water Environment Simulation Institute of Environmental Sciences Beijing Normal University Beijing P. R. China

In the Huanghe (Yellow) River basin,soil erosion is a serious problem,while runoff and sediment yield simulation has not been extensively studied on the basis of GIS (Geographic Information System) and distributed hydrological model. GIS-based SWAT (Soil and Water Assessment Tool) model was used to simulate runoff and sediment in the Huanghe River basin. The objective of this paper is to examine the applicability of SWAT model in a large river basin with high sediment runoff modulus,which could reach 770t/(km2·a). A two-stage "Brute Force" optimization procedure was used to calibrate the parameters with the observed monthly flow and sediment data from 1992 to 1997,and with input parameters set during the calibration process without any change the model was validated with 1998-1999’s observed data. Coefficient of examination (R2) and Nash-Suttcliffe simulation efficiency (Ens) were used to evaluate model prediction. The evaluation coefficients for simulated flow and sediment,and observed flow and sediment were all above 0.7,which shows that SWAT model could be a useful tool for water resources and soil conservation planning in the Huanghe River basin.

关键词： luohe river watershed SWAT model sediment flow

Effect of CH3OOH on the atmospheric concentration of OH radicals

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Progress in Natural Science:Materials International 2006年第11期16卷 1141-1149页

作者： WANG Caixia and CHEN Zhongming**(The State Key Laboratory of environmental Simulation and Pollution Control, college of environmental sciences, Peking university, beijing 100871, china) The State Key Laboratory of environmental Simulation and Pollution Control College of Environmental Sciences Peking University Beijing 100871 China

Methyl hydroperoxide （CH3OOH, MHP） is known to be a significant sink and reservoir of HOx and ROx radicals in the atmosphere. In order to investigate the impact of MHP on the concentration of atmospheric OH radicals, two key gas-phase reactions of MHP, i.e. the reactions with OH radicals and with UV photolysis, have been simulated at temperature of 293±2 K and total pressure of 1.01×105 Pa, using the long path Fourier transform infrared （LP-FTIR） spectrometry. OH radicals are generated by the photolysis of O3 in the presence of water vapor. Combined with the relative rate method, the reaction rate constant of MHP with OH radicals is determined to be （3.99±0.15）×10 -12 cm3·molecule -1 ·s -1 , and thus the atmospheric lifetime of MHP is estimated at 2.9 days. Furthermore, from detailed analysis of the UV photolysis of MHP, the yield of OH radicals is obtained to be 0.91±0.04. Based on the MHP atmospheric lifetime and the yield of OH radicals, it is concluded that MHP plays an essential role in the redistribution of OH radicals in the troposphere.

关键词： OH radicals methyl hydroperoxide rate coefficient UV photolysis gas-phase reaction LP-FTIR.

Optimization　of　harmonious　development　on　regional　energy－economy－atmospheric　environment　system

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Journal of environmental sciences 1996年第4期8卷 390-396页

作者： Ning Datong,Wang Lei(Chinese Real Estate Appraisal and Consulting Center,State Land Administration, Beiging,china.)(Institute of environmental sciences,beijing normal university,beijing 100875,china) Institute of environmental sciences Beijing Normal University Beijing 100875 China Chinese Real Est. Appraisal/C.C. State Land Administration Beiging China

The energy,industrial economy and atmospheric environment were taken into account as a whole cornplex system in this study. Based on the application of grey system theory and the analysis of development coefficients about major parameters of the system,the method of grey developrnent decision was approached, and a new concept-integrated development coefficient was put forward. Furthermore,the reasonable ranking of development decision within eight industrial sectors(building materials,coking,food and drink,chemical engineering,paper rnaking,machinery and electrical appliance,textile, mining)has been concluded from the viewpoint of economic growth, energy saving and ambient air quality protection.

关键词： economy atmospheric environment grey development decision.

Cytotoxicity, apoptosis induction, and mitotic arrest by a novel podophyllotoxin glucoside, 4DPG, in tumor cells

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Acta Pharmacologica Sinica 2005年第8期26卷 1000-1008页

作者： Yi-lin QI~(2,4), Fan LIAO~(2,4), Chang-qi ZHAO~2, Yong-da LIN~2, Ming-xue ZUO~(2,3,5) ~2 college of Life sciences, beijing normal university, beijing 100875 china ~3 Key Laboratory for Molecular Biology and Gene Engineering Drugs of beijing, beijing 100875, china college of Life sciences Beijing Normal University Beijing China Key Laboratory for Molecular Biology and Gene Engineering Drugs of beijing Beijing China

Aim: To define the in vitro cytotoxic activities of 4-demethyl-picropodophyllotoxin 7'-O-β-D-glucopyranoside （4DPG）, a new podophyllotoxin glucoside. Methods: Antiproliferation activity was measured in several tumor cell lines by using the microculture tetrazolium MTT assays. Cell cycle distribution was analyzed using flow cytometry and mitosis index assays. Furthermore, transmission electron microscopy, TUNEL, DNA agarose electrophoresis, and activated caspase-3 were used to analyze the induction of apoptotic cell death. Moreover, intracellular changes in the cytoskeleton were detected using immunocytochemistry. Results: 4DPG effectively inhibited the proliferation of cancer cells （HeLa, CNE, SH-SY5Y, and K562 cell lines）. For the K562 cell line, the antiproliferation effect of 4DPG was much more potent than that of etoposide (IC50value: 7.79x10（-9） mol/L for 4DPG vs 2.23x 10（-5） mol/L for etoposide). Further, 4DPG blocked the cell cycle in the mitotic phase. The induction of apoptosis and elevated levels of activated caspase-3 were confirmed in cells treated with 4DPG. The microtubule skeleton of HeLa cells was disrupted immediately after treatment with 4DPG. Conclusion: The cytotoxicity of 4DPG is due to its inhibition of the microtubule assembly of cancer cells at a low concentration, thus inducing apoptosis. These properties qualify 4DPG to be a potential antitumor drug.

关键词： 4-demethyl-picropodophyllotoxin 7’-O-β-D-glucopyranoside podophyllotoxin flow cytometry microtubulin apoptosis

Protective Effects of Vitamin E against Oxidative Damage Induced by Aβ(1-40)Cu(Ⅱ)Complexes

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Acta Biochimica et Biophysica Sinica 2007年第2期39卷 123-130页

作者： Xueling DAI~1 Yaxuan SUN~2 and Zhaofeng JIANG~2 ~1college of Life Science,Capital normal university,Bejing 100037,china ~2college of Applied sciences Humanities of beijing Union university,beijing 100083,china college of Life Science Capital Normal UniversityBeijing 100037 China college of Applied sciences and Humanities of beijing Union universitybeijing 100083 China

β-amyloid peptide （Aβ） is considered to be responsible for the formation of senile plaques,which is the hallmark of Alzheimer's disease （AD）.Oxidative stress,manifested by protein oxidation andlipid peroxidation,among other alterations,is a characteristic of AD brain.A growing body of evidence hasbeen presented in support of Aβ1-40forming an oligomeric complex that binds copper at a CuZn superoxidedismutase-like binding site. Aβ1-40Cu（Ⅱ） complexes generate neurotoxic hydrogen peroxide （H2O2） from O2via Cue+ reduction,though the precise reaction mechanism is *** toxicity of Aβ1-40or the Aβ1-40Cu（Ⅱ）complexes to cultured primary cortical neurons was partially attenuated when （+）-α-tocopherol （vitamin E）as free radical antioxidant was added at a concentration of 100 μ*** data derived from lactate dehydro-genase （LDH） release and the formation of H2O2confirmed the results from the MTT *** findingsindicate that copper binding to Aβ1-40can give rise to greater production of H2O2, which leads to a break-down in the integrity of the plasma membrane and subsequent neuronal *** treated with vitaminE exhibited much slighter damage,suggesting that vitamin E plays a key role in protecting neuronal cellsfrom dysfunction or death.

关键词： Aβ1-40Cu(II)complex vitamin E neuronal oxidative damage H2O2 generation lactate dehydrogenase(LDH)release