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Syntheses of amphiphilic biodegradable copolymers of poly(ethyl ethylene phosphate) and poly(3-hydroxybutyrate) for drug delivery

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science china Chemistry 2009年第7期52卷 961-968页

作者： CHENG Jing1 & WANG Jun2 1 Department of Polymer science and engineering, University of science and Technology of china, Hefei 230026, china 2 Hefei National Laboratory for Physical sciences at Microscale, School of life sciences, University of science and Technology of china, Hefei 230027, china Department of Polymer science and engineering University of Science and Technology of China Hefei 230026 China Hefei National Laboratory for Physical sciences at Microscale School of Life Sciences University of Science and Technology of China Hefei 230027 China

Biodegradable and amphiphilic triblock copolymers poly(ethyl ethylene phosphate)-poly(3-hydroxybutyrate)-poly(ethyl ethylene phosphate) (PEEP-b-PHB-b-PEEP) have been successfully synthesized through ring-opening polymerization. The structures are confirmed by gel permeation chromatography and NMR analyses. Crystallization investigated by X-ray diffraction reveals that the block copolymer with higher content of poly(ethyl ethylene phosphate) (PEEP) is more amorphous, showing decreased crystallizability. The obtained copolymers self-assemble into biodegradable nanoparticles with a coreshell micellar structure in aqueous solution, verified by the probe-based fluorescence measurements and transmission electronic microscopy (TEM) observation. The hydrophobic poly(3-hydroxybutyrate) (PHB) block serves as the core of the micelles and the micelles are stabilized by the hydrophilic PEEP block. The size and size distribution are related to the compositions of the copolymers. Paclitaxel (PTX) has been encapsulated into the micelles as a model drug and a sustained drug release from the micelles is observed. MTT assay also demonstrates that the block copolymers are biocompatible, rendering these copolymers attractive for drug delivery.

关键词： poly(3-hydroxybutyrate) polyphosphoester drug delivery polymeric nanoparticles

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Cis-regulatory element-based genome-wide identification of DREB1/CBF targets in Arabidopsis

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Progress in Natural science:Materials International 2008年第5期18卷 579-583页

作者： Huan Zhao a, Weizhong Liu a,b, Yong Hu a, Xianglin Liu a, Yikun He a, a college of life science, Capital Normal University, Beijing 100037, china b college of life sciences, Shanxi Normal University, Linfen 041004, china college of life science Capital Normal University Beijing 100037 China college of life sciences Shanxi Normal University Linfen 041004 China

Microarray analysis is used to identify transcriptional targets. However, the direct targets of transcription factors cannot be distin- guished from indirect ones; further, genes with low-expression levels cannot be identi ed by this method. In the present study, we exploit the cis-element dehydration-responsive element (DRE) that is known to be responsible for the transcription of DRE binding factor 1 (DREB1) targets in the promoter region of all Arabidopsis genes. Putative targets whose promoters contain the elements were veri ed by both microarray and reverse transcription-polymerase chain reaction (RT-PCR) analysis. Five new DREB1/CBF direct targets were identi ed. Compared with traditional microarray analysis, our method is convenient and cost-e ective for identifying the downstream targets of transcription factors.

关键词： Arabidopsis Cis-element Transcription factor DREB1/CBF Stress

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Peplomycin induces G1-phase specific apoptosis in liver carcinoma cell line Bel-7402 involving G2-phase arrest

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Acta Pharmacologica Sinica 2004年第12期25卷 132-138页

作者： Hong-ying CHEN2, Cong-yi ZHENG2, Guo-lin ZOU2, Da-xing XIE3, Jian-ping GONG3 2college of life sciences, Wuhan University, Wuhan 430072 3Cancer Research Institute, Tongji Hospital, TongjiMedical college, Huazhong University of science and Technology, Wuhan 430072, china college of life sciences Wuhan University Wuhan 430072 China

AIM: To investigate the mechanism of peplomycin (PEP)-induced apoptosis in liver carcinoma cell line (Bel-7402). METHODS: Growth inhibition by PEP was analyzed using 3- 4,5-Dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT) assay. Apoptotic cells were detected using Hoechest 33258 staining, and confirmed by flow cytometric analysis and DNA fragmentation analysis. The expression of cyclin A and B1 were determined by flow cytometry and Western blot. Annexin V assay was measured by flow cytometric analysis. RESULTS: PEP induced apoptosis and then inhibited cell proliferation in liver carcinoma cell line Bel-7402. Cells treated with PEP 50 μmol/Lfor 15 h were arrested in G2-phase with dramatical expression of cyclin A and a little change in cyclin B1. Almost all the apoptosis occurred in cells undergoing the G1-phase after treatment for 24 h. CONCLUSION: Peplomycin induced G1-phase specific apoptosis in Bel-7402 involving G2-phase arrest.

关键词： peplomycin Bel-7402 cells apoptosis cyclins cell cycle flow cytometry

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Influences of Quinclorac on Culturable Microorganisms and Soil Respiration in Flooded Paddy Soil

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Biomedical and Environmental sciences 2003年第4期16卷 314-322页

作者： ZHEN-MEI LU, HANG MIN , AND YANG-FANG YE Institute of Microbiology, college of life science, Zhejiang University, Hangzhou 310029, Zhejiang, china Institute of Microbiology College of Life Science Zhejiang University Hangzhou 310029 Zhejiang China

Objective To investigate the potential effects of herbicide quinclorac (3,7-dichloro-8-quinoline-carboxylic) on the culturable microorganisms in flooded paddy soil. Methods Total soil aerobic bacteria, actinomycetes and fungi were counted by a 10-fold serial dilution plate technique. Numbers of anaerobic fermentative bacteria (AFB), denitrifying bacteria (DNB) and hydrogen-producing acetogenic bacteria (HPAB) were numerated by three-tube anaerobic most-probable-number (MPN) methods with anaerobic liquid enrichment media. The number of methanogenic bacteria (MB) and nitrogen-fixing bacteria (NFB) was determined by the rolling tube method in triplicate. Soil respiration was monitored by a 102G-type gas chromatography with a stainless steel column filled with GDX-104 and a thermal conductivity detector. Results Quinclorac concentration was an important factor affecting the populations of various culturable microorganisms. There were some significant differences in the aerobic heterotrophic bacteria. AFB and DNB between soils were supplemented with quinclorac and non-quinclorac at the early stage of incubation, but none of them was persistent. The number of fungi and DNB was increased in soil samples treated by lower than 1.33μg·g-1 dried soil, while the CFU of fungi and HPAB was inhibited in soil samples treated by higher than 1.33μg·g-1 dried soil. The population of actinomycete declined in negative proportion to the concentrations of quinclorac applied after 4 days. However, application of quinclorac greatly stimulated the growth of AFB and NFB. MB was more sensitive to quinclorac than the others, and the three soil samples with concentrations higher than 1 μg·g-1 dried soil declined significantly to less than 40% of that in the control, but the number of samples with lower concentrations of quinclorac was nearly equal to that in the control at the end of experiments. Conclusion Quinclorac is safe to the soil microorganisms when applied at normal concentrations (0.67

关键词： Quinclorac Soil culturable microorganisms Soil respiration Flooded paddy soil

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Large eddies induced by local impulse at wall of boundary layer with pressure gradients

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Progress in Natural science:Materials International 2008年第7期18卷 873-878页

作者： Changgen Lu a,b,*, Weidong Caob, Yanmei Zhang b, Jintao Pengb a college of Atmospheric science, Nanjing University of Information science & Technology, Nanjing 210044, china b college of Environmental science and engineering, Hohai University, Nanjing 210098, china college of Atmospheric science Nanjing University of Information Science & Technology Nanjing 210044 China college of Environmental science and engineering Hohai University Nanjing 210098 China

Large eddies induced by local impulse at the wall with pressure gradients in the boundary layer was studied by direct numerical sim- ulations. The results show that the amplitude evolution, the high and low speed stripes, the formation of streamwise vortices, the ejection and sweeping, inflexions and distortion at the mean velocity profiles, as well as other characteristics, are consistent with the experimental and other numerical results. It is also found that large eddies are easy to be excited with adverse pressure gradient in the boundary layer, and the growth of amplitudes, formation of streamwise vortices and the influencing area etc., are much larger than those with favorable pressure gradient in the boundary layer. In contrast, large eddies are hardly to be induced through local impulse disturbance at the wall with favorable pressure gradients in the boundary layer.

关键词： Boundary layer Pressure gradients Impulse Large eddies

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Single-channel blind separation of overlapped multicomponents based on energy operator

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science china(Information sciences) 2010年第1期53卷 147-157页

作者： CAI QuanWei, WEI Ping & XIAO XianCi college of Electronic engineering, University of Electronic science and Technology of china, Chengdu 610054, china 1. college of Electronic engineering University of Electronic Science and Technology of China Chengdu 610054 China

A method utilizing single channel recordings to blind separate the multicomponents overlapped in both time and frequency domains is proposed in this paper. The main idea of the method is based on using the energy operator and differential energy operator to estimate instantaneous frequencies and amplitudes of each component and then to reconstruct these components. This method, due to the good time resolution of the energy operator and differential energy operator, as well as the very low computational complexity, is very useful in real time processing and practical applications. Simulation results demonstrated the effciency of this method.

关键词： single channel time frequency overlap multicomponents separation energy operator differential energy operator

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Homochiral expression of proteins:a discussion on the natural chirality related to the origin of life

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science china Chemistry 2010年第4期53卷 792-796页

作者： HU PingPing1,2, PENG Li2, ZHEN ShuJun3, CHEN LiQiang2, XIAO SaiJin1 & HUANG ChengZhi1,3 1Key Laboratory on Luminescence Real-Time Analysis, Ministry of Education college of Chemistry and Chemical engineering, Southwest University, Chongqing 400715, china 2college of life science, Southwest University, Chongqing 400715, china 3college of Pharmaceutical sciences, Southwest University, Chongqing 400715, china 1. Key Laboratory on Luminescence Real-Time Analysis Ministry of Education Southwest University Chongqing 400715 China2. College of Life Science Southwest University Chongqing 400715 China4. College of Chemistry and Chemical Engineering Southwest University Chongqing 400715 China3. College of Pharmaceutical Sciences Southwest University Chongqing 400715 China

Homochirality in life has always been a driving force in scientific research and natural exploration. It has not been satisfactorily explained, and systematic investigations are necessary. This paper reported a homochiral expression of proteins dependent on the stirring direction of growing media. By controlling the stirring direction clockwise (CW) and anticlockwise (ACW) of the culture medium, proteins with distinct secondary structures were obtained, and D-amino acid may be included in the protein cultured with the stirring direction of ACW. Considering the effect of force fields, which might affect the process of folding and refolding of cellular protein in this report, the control of force fields might be a good way to prepare asymmetric drugs, and the rotational direction of the earth is possibly related to the chirality in primitive life molecules.

关键词： homochirality chiral expression prion protein fluorescence

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Electrochemical Characterization of Surface-modified LiMn_2O_4 Cathode Materials for Li-ion Batteries

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Journal of Wuhan University of Technology(Materials science) 2006年第4期21卷 56-59页

作者：禹筱元 college of science South China Agricultural University Guangzhou 510642ChinaSchool of Physics & Engineering Sun Yat-sen University Guangzhou 510275China

To improve the performance, the surface of 12Mn2O4 was coated with very fine MgO , Al2O3 and ZnO by solgel method, respectively. The structure and morphology of the coated materials were investigated by X-ray diffraction （ XRD ）, X-ray photoelectron spectroscopy （ XPS ） and scanning electron microscopy （SEM）. The charge and discharge performance of uncoated and surfnce modified 12Mn2O4 spinel at 25℃ and 55 ℃ were tested, using a voltage window of 3.0-4.35 V and a current deasity of 0. 1 C rate. There is a slight decrease in the initial discharge capacity relative to that of uncoated UMn2 O4, bat the cycle ability of 12 12Mn2O4 coated by metal-oxide has remarkably been improved. The EIS measuremeuts of uncoated and Al2O3 -coated 12Mn2O4 were carried out by a model 273 A potentiostatl galvanistat controUed by a computer using M270 software, and using a freqnency response analyzer （ Zsimpwin ） combined with a potentiostate （ PAR 273）. Coaseqnently, the reason for the improved cycle properties is that the surface modification reduces the dissolution of Mn , which results from the suppression of the electrolyte decomposition, and suppresses the formation of passivation film that acts as an electronic insulating layer. In conclusion, the use of surface modification is an effective way to improve the electrochemical performance of 12Mn2O4 cathode material for lithium batteries.

关键词： lithium-ion batteries surface modification metal-oxide coating: 12Mn2O4 cathode

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Effect of surfactants on the structure and photoelectric properties of ITO films by sol-gel method

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Rare Metals 2010年第2期29卷 143-148页

作者： LIU Jiaxiang, WU Da, ZHANG Nan, and WANG Yue college of Materials science and engineering, Beijing University of Chemical Technology, Beijing 100029, china college of Materials science and engineering Beijing University of Chemical Technology

The Indium tin oxide（ITO） thin film possesses excellent photoelectric properties that enable it to act as an ideal transparent *** obtain high-quality ITO films through sol-gel method, the ionic surfactant monoethanolamine and the non-ionic surfactant polyethylene glycol（PEG） were added to the ITO precursor *** influences of surfactants on the structural and photoelectric properties of ITO film samples were *** patterns indicated that surfactant monoethanolamine contributed to film predominant grain orientation along the（400） *** high transmittance（over 95%） was attributed to the preferred orientation and the grain size expansion of ITO *** showed that the surface particle size and the morphology of ITO films were strongly dependent on the kind of surfactants *** to the shortwave region, the absorption edge of the films exhibited the Burstein-Moss shift.

关键词： surfactants indium tin oxide films sol-gel structure photoelectricity

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ON THE LEAST SQUARES PROBLEM OF A MATRIXEQUATION

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Journal of Computational Mathematics 1999年第6期17卷 589-594页

作者： An-ping Liao(college of science, Hunan Normal University, Changsha 410081, china) Hunan Normal Univ Coll Sci Changsha 410081 Peoples R China

Least squares solution of F=PG with respect to positive semidefinite symmetric P is considered,a new necessary and sufficient condition for solvablity is given,and the expression of solution is derived in the some special cases. Based on the expression, the least spuares solution of an inverse eigenvalue problem for positive semidefinite symmetric matrices is also given.

关键词： least squares solution matrix equation inverse eigenvalue problem positive semidefinite symmetric matrix

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