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Miktoarms hyperbranched polymer brushes:One-step fast synthesis by parallel click chemistry and hierarchical self-assembly

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Science china Chemistry 2010年第12期53卷 2461-2471页

作者： HAN Yi & GAO Chao MOE key laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and Engineering,Zhejiang {3.,Hangzhou 3.0027,china 1. MOE key laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and Engineering Zhejiang University Hangzhou 310027 China

Spherical molecular brushes with amphiphilic heteroarms were facilely synthesized by grafting the arms of hydrophobic 2-azidoethyle palmitate and hydrophilic monoazide-terminated poly(ethylene glycol) onto the core of alkyne-modified hyperbranched polyglycerol (HPG) with high molecular weight (Mn=122 kDa) via one-pot parallel click *** parallel click grafting strategy was demonstrated to be highly efficient (～100%),very fast (～ 2 h) and well controllable to the amphilicity of molecular *** adjusting the feeding ratio of hydrophobic and hydrophilic arms,a series of brushes with different arm ratios were readily *** resulting miktoarms hyperbranched polymer brushes (HPG-g-C16/PEG3.3.) were characterized by hydrogen-nuclear magnetic resonance (1H NMR),Fourier transform infrared (FT-IR) spectroscopy,gel permeation chromatography (GPC),and differential scanning calorimetry (DSC) *** spherical molecular brushes showed high molecular weights up to 23. kDa,and thus could be visualized by {{3. force microscopy (AFM).AFM and dynamic laser light scattering (DLS) were employed to investigate the self-assembly properties of amphiphilic molecular brushes with closed proportion of hydrophobic and hydrophilic *** brushes could self-assemble hierarchically into spherical micelles,and network-like fibre structures,and again spherical micelles by addition of n-hexane into the dichloromethane or chloroform solution of *** addition,this kind of miktoarms polymer brush also showed the ability of dye loading via host-guest encapsulation,which promises the potential application of spherical molecular brushes in supramolecular chemistry.

关键词： miktoarms molecular brushes hyperbranched polyglycerol amphiphilic self-assembly

Recent progress on the structure of Ser/Thr protein phosphatases

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Science china(Life Sciences) 2008年第6期51卷 487-494页

作者： WANG BaiJing1,2, ZHANG Peng1 & WEI Qun1 1 Department of Biochemistry and molecular Biology, Beijing Normal university, Beijing key {3., Beijing 100875. china 2 School of Life Science, Changchun Normal university, Changchun 13.03., china 1. Department of Biochemistry and molecular Biology Beijing Normal University Beijing Key Laboratory Beijing 100875 China 2. School of Life Science Changchun Normal University Changchun 130032 China

PP1, PP2A and PP2B, belonging to the PPP family of Ser/Thr protein phosphatases, participate in regulating many important physiological processes, such as cell cycle control, regulation of cell growth and division regulation, etc. The sequence homology between them is relatively high, and ter- tiary structure is conserved. Because of the complexity of the structure of PP2A and the diversity of its regulatory subunits, its structure is less well known than those of PP1 and PP2B. The PP2A holoen- zyme consists of a heterodimeric core enzyme, comprising a scaffolding subunit and a catalytic sub- unit, as well as a variable regulatory subunit. In this study, the subunit compositions, similarities and differences between the Ser/Thr protein phsphatases structures are summarized.

关键词： Ser/Thr phosphatases subunit composition similarities and differences crystal structure

In situ X-ray diffraction study of structural evaluation in Fe_(73.Cu_(1.5.Nd_3.i_(13.5.B_9 amorphous alloy at high temperature

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Science china(Physics,Mechanics & Astronomy) 2008年第4期51卷 445-450页

作者： LI Gong,XU Tao,GAO YunPeng & LIU RiPing key laboratory of Metastable Materials Science and Technology,Yanshan university,Qinhuangdao 066004,{3. key laboratory of Metastable Materials Science Technology Yanshan University Qinhuangdao 066004 China

The thermodynamics structural relaxation of Fe73.u1.5.d3.i13.5.9 amorphous alloy from room temperature to 400℃ has been investigated by measuring the structure factor with in situ X-ray diffraction. The structural information of the atomic con-figuration such as radial distribution function (RDF) and neighbor atomic distance was gained by Fourier transformation. The research result shows that the amor-phous structure remains stable in the temperature range of 3. to 400℃ but exhibits distinct changes in local atomic configuration with the increase of temperature. The quantitative determination of the neighbor atomic distance suggests that the de-gree of short-range order changes by the temperature altering the second nearest neighbor local atomic configuration of the amorphous when structural relaxation occurs.

关键词： Fe-based amorphous alloys in situ X-ray diffraction short-range order structure

Fluorescence dynamics of interactions between polyamide PyPyPyβDp and DNA

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Science china Chemistry 2006年第1期49卷 75-80页

作者： ZHANG Huijuan1,2, WANG Jin3. WU Yishi1, YUAN Gu3. AI Xicheng1, WANG Li4 & ZHANG Jianping1 1. State key laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, china 2. School of Life Science and Technology, Beijing Institute of Technology, Beijing 100081, china 3. College of Chemistry and molecular Engineering, Peking {5., Beijing 100080, china 4. Center for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, china Correspondence should be addressed to Ai Xicheng and Zhang Jianping 1. State key laboratory for Structural Chemistry of Unstable and Stable Species Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China 2. School of Life Science and Technology Beijing Institute of Technology Beijing 100081 China 3. College of Chemistry and molecular Engineering Peking University Beijing 100080 China 4. Center for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China

The photophysical properties of the polyamide PyPyPyβDp (PPP) were investigated by means of steady-state absorption and fluorescence spectroscopies, as well as time-resolved fluo-rescence spectroscopy. It was found that the excited-state properties of PPP are very sensitive to solvents. In TKMC buffer PPP exhibited weak fluorescence with a decay time constant of 16 ps, while with the decrease of the solvent polarity PPP showed the blue-shifted peak position, increased inten-sity and lengthened life-time for its fluorescence behavior. In the presence of calf thymus DNA, it was observed that the fluorescence intensity was enhanced and the fluorescence lifetime increased from 16 to 3. ps for PPP, which verified that PPP bound into the minor groove of DNA duplex.

关键词： polyamide (PPP), calf thymus DNA (ctDNA), time-resolved fluorescence spectroscopy, recognition dynamics.

Magnetism and piezoelectricity of hexagonal boron nitride with triangular vacancy

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Chinese Physics B 2018年第1期27卷 450-455页

作者：赵路丝陈春平刘林林于洪侠陈怡王晓春 Institute of atomic and molecular Physics Jilin University Jilin Provincial key laboratory of Applied atomic and {3. Spectroscopy (Jilin university)

First-principle calculations reveal that the configuration system of hexagonal boron nitride （h-BN） monolayer with triangular vacancy can induce obvious magnetism, contrary to that of the nonmagnetic pristine boron nitride monolayer. Interestingly, the h-BN with boron atom vacancy （VB-BN） displays metallic behavior with a total magetic moment being 0.46μB per cell, while the h-BN with nitrogen atom vacancy （VN-BN） presents a half-metallic characteristic with a total magnetic moment being 1.0μB per cell. Remarkably, piezoelectric stress coefficient ell of the VN-BN is about 1.5.times larger than that of pristine h-BN. Furthermore, piezoelectric strain coefficient dll （12.42 μm/V） of the VN-BN is 20 times larger than that of pristine h-BN and also one order of magnitude larger than the value for the h-MoS2 monolayer, which is mainly due to the spin-down electronic state in the VN-BN system. Our study demonstrates that the nitrogen atom vacancies can be an efficient route to tailoring the magnetic and piezoelectric properties of h-BN monolayer, which have promising performances for potential applications in nano-electromechanical systems （NEMS） and nanoscale electronics devices.

关键词： first-principle magnetism piezoelectric nano-electromechanical systems

Thermal conductivity of nanoscale thin nickel films

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Progress in Natural Science:Materials International 2005年第10期 60-67页

作者： YUAN Shiping and JIANG Peixue (key laboratory of Thermal Science and Power Engineering, Department of Thermal Engineering, tsinghua university, Beijing {3., china) key laboratory of Thermal Science and Power Engineering Department of Thermal Engineering Tsinghua University Beijing 100084 China

The inhomogeneous non-equilibrium molecular dynamics (NEMD) scheme is applied to model phonon heat conduction in thin nickel films. The electronic contribution to the thermal conductivity of the film is deduced from the electrical conductivity through the use of the Wiedemann-Franz law. At the average temperature of T = 3.0 K, which is lower than the Debye temperature (?)= 45. K, the results show that in a film thickness range of about 1 -11 nm, the calculated cross-plane thermal conductivity decreases almost linearly with the decreasing film thickness, exhibiting a remarkable reduction compared with the bulk value. The electrical and thermal conductivities are anisotropic in thin nickel films for the thickness under about 10 nm. The phonon mean free path is estimated and the size effect on the thermal conductivity is attributed to the reduction of the phonon mean free path according to the kinetic theory.

关键词： nanoscale nickel films thermal conductivity electrical conductivity.

Characterization of interspecific hybrids and backcross progenies from a cross between Oryza minuta and Oryza sativa

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Science china(Life Sciences) 2009年第12期52卷 1148-1155页

作者： GUO SiBin, QIN FaLan, ZHANG DuanPin & LIN XingHua· National key laboratory of Crop Genetic Improvement, National Center of Crop molecular Breeding, Huazhong Agricultural {3., Wuhan 43.070, china National key laboratory of Crop Genetic Improvement National Center of Crop Molecular Breeding Huazhong Agricultural University Wuhan 430070 China

Oryza minuta, a tetraploid wild relative of cultivated rice, is an important source for the genetic improvement. Interspecific hybrids were obtained from the cross of O. sativa L. (IR24) and O. minuta (Acc. No. 10113.) with 5.5.% crossability, which ranged from 0.11% to 1.62% in the backcross generations. The chromosome numbers of the backcross progenies were 24 to 48. Seven yield-related traits of the parents, hybrid F1, and backcross progenies were evaluated. Simple sequence repeat markers analysis showed that the polymorphism ratio of SSR bands between IR24 and Acc. No. 10113. was 93.2%. The average donor segment number, length, donor genome size, and percentage of donor genome of 92 BC3.1 plants (2n=24) were 24.1, 17.8 cM, 43..4 cM and 26.2%, respectively. They were complex variation and uneven among the chromosomes. These introgression lines could be used to identify the favorable genes of O. minuta and provide a new platform for the genetic improvement of cultivated rice.

关键词： Oryza sativa L. Oryza minuta interspecific hybridization backcross progeny introgression line

H~+-ATPase in the plasma membrane of Arabidopsis pollen cells is involved in extracellular calmodulin-promoted pollen germination

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Progress in Natural Science:Materials International 2009年第9期19卷 1071-1078页

作者： Wending Sun1, Sujuan Li1, Junying Xu, Ting Liu, Zhonglin Shang* Hebei key laboratory of molecular and Cellular Biology, College of Life Sciences, Hebei Normal {3., Shijiazhuang 05.016, china [a]Hebei key laboratory of molecular and Cellular Biology College of Life Sciences Hebei Normal University Shijiazhuang 050016 China

In this paper, the role of the plasma membrane (PM) H+-ATPase in extracellular calmodulin (CaM)-promoted pollen germination and in tube growth of Arabidopsis thaliana was investigated. Pollen germination, pollen tube growth rate, free cytosolic Ca2+ concentration ([Ca2+]cyt) and Ca2+ channel activity in the PM of pollen cells were measured. In response to fusicoccin or CaM treatment, in vitro pollen germination and pollen tube growth rate, [Ca2+]cyt and activity of a hyperpolarization-activated Ca2+-permeable channel increased. Sodium vanadate inhibited the promotion of these parameters by extracellular CaM. The results suggest that H+-ATPase may be involved in extracellular CaM-regulated pollen germination and in tube growth by modulation of the hyperpolarization-activated Ca2+ channel in the PM of A. thaliana pollen cells.

关键词： Arabidopsis thaliana H+-ATPase Pollen Extracellular calmodulin Hyperpolarization-activated calcium channel

Biological networks to the analysis of microarray data

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Progress in Natural Science:Materials International 2006年第12期16卷 1242-1251页

作者： FANG Zhuo~1, LUO Qingming~1**, ZHANG Guoqing~1 and LI Yixue~2**(1. Hubei Bioinformatics and molecular Imaging key laboratory,Huazhong {3. of Science and Technology, Wuhan 43.074, china 2. Shanghai Center for Bioinformation and Technology, Shanghai 20023.5} china) [a]Hubei Bioinformatics and molecular Imaging key laboratory Huazhong University of Science and Technology Wuhan China [b]Shanghai Center for Bioinformation and Technology Shanghai China

Microarray technology, which permits rapid and large-scale screening for patterns of gene expressions, usually generates a large amount of data. How to mine the biological meanings under these data is one of the main challenges in bioinformatics. Compared to the pure mathematical techniques, those methods incorporated with some prior biological knowledge generally bring better interpretations. Recently, a new analysis, in which the knowledge of biological networks such as metabolic network and protein interaction network is introduced, is widely applied to microarray data analysis. The microarray data analysis based on biological networks contains two main research aspects: identification of active components in biological networks and assessment of gene sets significance. In this paper, we briefly review the progress of these two categories of analyses, especially some representative methods.

关键词： biological networks microarray data analysis subnetwork gene set.