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MORPHOLOGICAL TRANSITION BETWEEN VESICLES AND TUBULES FOR A GLYCOPOLYMER-CONTAINING AMPHIPHILIC DIBLOCK COPOLYMER IN AQUEOUS SOLUTIONS

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Chinese Journal of Polymer science 2001年第3期19卷 297-301页

作者： Zi-chen Li Yue Shen Yu-zeng Liang Fu-mian Li Department of Polymer science & Engineering college of Chemistry peking university beijing 100871, china 北京大学北京

The morphological transition of molecular assemblies in aqueous solutions for a new amphiphilic diblock copolymer induced by changing the initial solvent conditions was studied by transmission electron microscopy (TEM). The copolymer was polystyrene(77)-b-poly[2-(beta -D-glucopyranosyloxy)ethyl acrylate (6)] (PSt(77)-b-PGEA(6)) and the solvent was a mixture of DMF and THF. PSt(77)-b-PGEA(6) yields vesicles and tubules when it is initially dissolved in THF and DMF respectively. The morphological transition between vesicles and tubules can be achieved by simply varying the amounts of THF and DMF, or changing the temperature at which the aggregates were prepared.

关键词： block copolymer amphiphile glycopolymer self-assembly tubule vesicle

Density functional theory study of the magnetic properties of rare earth complexes:the magnetic coupling mechanism in Y~Ⅲ and Gd~Ⅲ complexes with nitronyl nitroxide

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science china Chemistry 2009年第11期52卷 1961-1968页

作者： REN Jie1,2,WANG BingWu1 & CHEN ZhiDa1 1 beijing National Laboratory for molecular sciences,State Key Laboratory of Rare Earth Materials Chemistry and Applications,college of Chemistry and molecular Engineering,peking university,beijing 100871,china 2 college of science,Hebei university of science and Technology,Shijiazhuang 050018,china beijing National Laboratory for molecular sciences State Key Laboratory of Rare Earth Materials Chemistry and Applications College of Chemistry and Molecular Engineering Peking University Beijing China college of science Hebei University of Science and Technology Shijiazhuang China

The magnetic coupling interactions of the nitronyl nitroxide radicals bound to diamagnetic(YⅢ) and paramagnetic(GdⅢ) rare earth ions in two model magnetic systems based on novel rare earth organic radical complexes Ln(hfac)3(NITPhOCH3)2(Ln=YⅢ 1,GdⅢ 2;hafc = hexafluoroacetylacetonate;NIT-PhOCH3 = 4'-methoxyo-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) have been investigated by density functional theory(DFT).The magnetic coupling mechanisms were also explored from the viewpoint of molecular orbital and spin density *** calculations show that the empty 4d-orbitals of YⅢ and 5d-orbitals of GdⅢ play an important role in the antiferromagnetic coupling between the two nitronyl nitroxide radical ligands,and that the ferromagnetic coupling between the GdⅢ ion and the radical magnetic centers can be attributed to the nearly complete localization of the isotropic 4f-shell and singly occupied magnetic orbital(π) of the nitronyl nitroxide.

关键词： magnetic coupling density functional theory rare earth ion gadolinium(Ⅲ) complexes yttrium(Ⅲ) complexes

IMPACT PROPERTIES OF METALLOCENE - CATALYZED ETHYLENE-α-OLEFIN COPOLYMERS

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Chinese Journal of Polymer science 2002年第5期20卷 473-480页

作者： Xu-rong Xu Jun-ting Xu Lin-xian Feng Department of Polymer science and Engineering Zhejiang university Hangzhou 310027,china Department of Polymer science and Engineering college of Chemistry & molecular Engineering peking university beijing 100871, china Department of Polymer science and Engineering Zhejiang University Hangzhou 310027

The impact properties of two selected metallocene-catalyzed ethylene-butene copolymers and one conventionalcopolymer were evaluated using Izod impact test. It is found that the metallocene-catalyzed copolymer shows superior impactproperties. This result was explained on the basis of the more homogeneous inter-molecular composition distribution andnarrower molecular weight distribution, which leads to more homogeneous morphology with fewer defects. Stepwisecrystallization improves the impact properties, especially in the crack propagation process, to a large extent. This is due to thedecrease of entanglements by stepwise crystallization, which is advantageous for the chain slip and shear. The polymer withheterogeneous intra-molecular composition distribution exhibits a more evident improvement of impact properties understepwise crystallization.

关键词： Metallocene-catalyzed ethylene-butene copolymer Impact properties molecular heterogeneities Thermal treatment

SYNTHESIS OF PERFLUORO-1-OCTANESULFONATED FULLERENE AND THE FRICTION PROPERTIES OF ITS THIN FILM

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Chinese Journal of Polymer science 2002年第5期20卷 397-400页

作者： Lan Huang Shuang Fan Fang Wei Xin-sheng Zhao Jin-xin Xiao Bu-yao Zhu college of Chemistry and molecular Engineering peking university beijing 100871, china college of Chemistry and molecular Engineering Peking University 北京 100871

A star-shaped compound of perfluoro-1-octanesulfonated fullerene was synthesized. The measurement of the friction for its spin-coating film by friction force microscopy (FFM) reveals that the films possess lower frict... 详细信息

关键词： perfluoro-1-octanesulfonated fullerene thin film friction force microscopy (FFM)

Real-time detection of α1A-AR movement stimulated by phenylephrine in single living cells

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Acta Pharmacologica Sinica 2007年第6期28卷 796-802页

作者： Ning XU~(2,5),Zhang-yi LIANG~(3,5),Ming XU~2,Ying-hua GUAN~3,Qi-hua HE~4,Qi-de HAN~2,Xin-sheng ZHAO~(3,6),You-yi ZHANG~(2,6)~2 institute of Vascular medicine,peking university Third Hospital,and Key Laboratory of molecular Cardiovascular sciences,Ministry ofEducation,beijing 100083,china ~3 beijing National Laboratory for molecular sciences,State Key Laboratory for Structural Chemistry ofUnstable and Stable Species,and Department of Chemical Biology,college of Chemistry and molecular Engineering,peking university,beijing 100871,china ~4 Center of Medical Analysis,peking university,Health science Center,beijing 100083,china institute of Vascular medicine Peking University Third Hospital and Key Laboratory of Molecular Cardiovascular Sciences Ministry of Education Beijing China beijing National Laboratory for molecular sciences State Key Laboratory for Structural Chemistry of Unstable and Stable Species Department of Chemical Biology College of Chemistry and Molecular Engineering Peking University Beijing China Center of Medical Analysis Peking University Health Science Center Beijing China

Aim:To investigate the movement of α1A-adrenergic receptors(α1A-AR) stimu-lated by agonist,phenylephrine （PE）,and the dynamics of receptor movement inreal time in single living cells with millisecond ***:We labeledα1A-AR using the monoclonal,anti-FLAG （a kind of tag） antibody and Cy3-conju-gated goat anti-mouse IgG and recorded the trajectory of their transport processin living HEK293A cells stimulated by agonist,PE,and then analyzed their dy-namic ***:The specific detection of α1A-AR on the surface ofliving HEK293A-α1Acells was achieved.α1A-AR internalize under the stimulationof *** the cells were stimulated with PE for 20 min,apparent colocalizationwas found between α1A-AR and *** 40 min stimulation of PE,trajecto-ries of approximate linear motion in HEK293A-α1Acells were recorded,and theirvelocity was ***:The specific labeling method on the livingcell surface provides a convenient means of real-time detection of the behavior ofsurface *** this method we were able to specifically detect α1A-AR andrecord the behavior of individual particles of receptors with 50 ms exposure time inreal time in single living cells.

关键词： adrenergic receptor trajectory living cell

Taurine inhibits ischemia/reperfusion-induced compartment syndrome in rabbits

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Acta Pharmacologica Sinica 2005年第7期26卷 821-827页

作者： Ji-xian WANG~(2,3) Yan LI~2 Li-ke ZHANG~4 Jing ZHAO~5 Yong-zheng PANG~(2,3) Chao-shu TANG~(3,5) Jing ZHANG~(2,3,6) 1 institute of Cardiovascular Disease Research,The First Hospital of peking university,beijing 100034,china 3 Key Laboratory of molecular Cardiovascular science,Ministry of Education,beijing 100083,china 4 Department of Pathophysiology,Capital institute of medicine,beijing 100054,china 5 Department of Physiology Health Center of Medical sciences,peking university,beijing 100083,china institute of Cardiovascular Disease Research The First Hospital of Peking University Beijing China Key Laboratory of molecular Cardiovascular science Ministry of Education Beijing China Department of Pathophysiology Capital Institute of Medicine Beijing China Department of Physiology Health Center of Medical Sciences Peking University Beijing China

Aim:To investigate effects of taurine on ischemia/reperfusion(I/R)-induced com-partment syndrome in rabbit hind ***:Rabbits underwent femoralartery occlusion after ligation of branches from terminal aorta to femoral *** a 7-h ischemia,reperfusion was established with the use of heparinizedpolyethylene *** received taurine(1 g/kg)or normal saline(control)by iv infusion 10 min before shunt *** reperfusion,anterior com-partment pressure(ACP)was monitored continuously in the left lower *** muscle triphenyltetrazolium chloride(TTC)level,taurine contentand myeloperoxidase activity were *** stress was induced in thein vitro gastrocnemius muscle slices by free radical generating systems(FRGS),and the malondialdehyde content was measured in presence or absence of ***:After 7 h of ischemia,none of the parameters that we measured weredifferent from those before ischemia,except that TTC reduction decreased by80%.In the control group,after 2 h of reperfusion,ACP increased 4.5-fold,andgastrocnemius muscle taurine content was reduced by 33%.In taurine-treatedanimals,at 2 h reperfusion,the mean arterial blood pressure and heart rate wereincreased,by 6% and 10%.ACP decreased by 39%,muscle edema decreased by16%,TTC reduction increased by 150%,and lactate dehydrogenase decreased by36% compared to control *** and muscle taurine content increased by70% and 88%,*** the taurine-treated group,at 2 h repeffusion,plasmamalondialdehyde and conjugated diene content were decreased by 38% and 23%,respectively,and muscle malondialdehyde and conjugated diene content decreasedby 22% and 30%,respectively compared to the control *** 2 h reperfusion,myeloperoxidase activity was increased 3.5-fold in control *** the in vitrostudy,taurine decreased malondialdehyde content in muscle slices incubatedwith hypochlorous acid in a dose-dependent manner,but there was no changewhen incubated

关键词： taurine compartment syndromes reperfu sion injury

SMALL ANGLE LIGHT SCATTERING MEASUREMENT OF THE ISOTROPIC TO NEMATIC TRANSITION OF A SIDE CHAIN NEMATIC POLYMETHACRYLATE

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Chinese Journal of Polymer science 2002年第5期20卷 431-437页

作者： Zhong-ming Hu Ren-yuan Qian Shou-xi Chen Xiao-fang Chen Qi-feng Zhou Centre for molecular science, institute of Chemistry Chinese Academy of sciences, beijing 100080, china Department of Polymer science & Engineering college of Chemistry & molecular Engineering peking university beijing 100871, china Centre for molecular science Institute of Chemistry Chinese Academy of Sciences 北京 100080 Department of Polymer science & Engineering College of Chemistry & Molecular Engineering Peking University 北京 100871

The kinetics of I-->N transition of a side chain nematic polymethacrylate has been studied by small angle depolarized light scattering intensity measurements using a charge coupled device linear image sensor. The polymer shows the transition temperatures K52N79I in degreesC, The H-v scattering intensity T(q,t) during the transition I (at 80.2degreesC)-->N (at 75.8degreesC) shows that T(q) is independent of q for all t, and during the initial stage (in 6 s) T(t) increases exponentially with t. In the later stage of the transition T(t) approaches a saturation value in 2 min. This experimental result indicates that the I-->N transition of a liquid crystalline polymer is a spinodal type of phase transition mediated by orientation fluctuation.

关键词： side chain nematic polymer isotropic-nematic transition small angle depolarized light scattering

Measurement of Monomer Reactivity Ratios of D,L-3-Methylglycolide with Glycolide or D,L-Lactide

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Chinese Chemical Letters 2000年第9期11卷 815-818页

作者： Chang Ming DONG Kun Yuan QIU Zhong Wei GU Xin De FENG Department of Polymer science and Engineering, college of Chemistry and molecular Engineering, peking university, beijing 100871 National Research institute for Family Planning, beijing 100081 Dept. of Poly. Sci. and Engineering Coll. of Chem. and Molec. Eng. Peking University Beijing 100871 China Natl. Res. Inst. for Family Planning Beijing 100081 China

For monomer reactivity ratios study, the copolymerization of D,L-3-methylglycolide (MG) with glycolide (GA) or D,L-lactide (LA) was carried out in bulk to a certain low conversion in the presence of stannous octoate at 140 degrees C. The copolymer compositions were determined by H-1 NMR spectroscopy. The monomer reactivity ratios were evaluated by Fineman-Ross method, Kelen-Tudos method and linear least-squares method. The monomer reactivity ratios of D,L-3-methylglycolide and glycolide or D,L-lactide are r(mg)= 0.73, r(ga)= 1.47; r(mg)= 1.71, r(la)= 0.92, respectively.

关键词： D,L-3-methylglycolide glycolide D,L-lactide ring-opening copolymerization monomer reactivity ratios

Expression of rice dwarf phytoreovirus Pns6 and the specificity analysis of its monoclonal antibodies

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science china(life sciences) 2009年第10期52卷 958-964页

作者： JI Xu, WEI ChunHong & LI Yi peking–Yale Joint Center for Plant molecular Genetics and Agrobiotechnology, the National Laboratory of Protein Engineering and Plant Genetic Engineering, college of life sciences, peking university, beijing 100871, china peking-Yale Joint Center for Plant molecular Genetics and Agrobiotechnology the National Laboratory of Protein Engineering and Plant Genetic Engineering College of Life Sciences Peking University Beijing China

The genome of rice dwarf phytoreovirus (RDV) is composed of 12 double-stranded RNA segments, of which segment S6 encodes a non-structural protein Pns6 identified as the movement protein. In this report, Pns6 with a 6-histidine tag at the N-terminal was expressed in E. coli after induction under low temperature (18℃) and low concentration (0.4 mmol/L and 0.2 mmol/L) of IPTG, and then purified by Ni-chelated affinity chromatography. Stability analysis indicated that the expressed HisPns6 protein was stable at 37℃ after 24 h treatment. This recombinant protein was then used to make monoclonal antibody. Total 18 hybridoma clones were obtained. The specificity of antibodies was tested by Western blot using native Pns6 extracted from RDV-infected rice leaves, and 15 positive clones were confirmed. Mapping of the antigenic sites of Pns6 using antibodies showed that the most sensitive antigen determinant is located in the C-terminal region (the 296th-509th amino acids) of Pns6, which is confirms bioinformatics analysis.

关键词： rice dwarf virus Pns6 expression monoclonal antibody antigen determinant