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Search Results: 1 - 10 of 16216 matches for " WenXin Su "
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Differential molecular information of maurotoxin peptide recognizing IKCa and Kv1.2 channels explored by computational simulation
Hong Yi, Su Qiu, Yingliang Wu, Wenxin Li, Baoshan Wang
BMC Structural Biology , 2011, DOI: 10.1186/1472-6807-11-3
Abstract: A reasonably stable MTX-IKCa complex was obtained by combining various computational methods and by in-depth comparison with the previous model of the MTX-Kv1.2 complex. Similarly, MTX adopted the β-sheet structure as the interacting surface for binding both channels, with Lys23 occluding the pore. In contrast, the other critical residues Lys27, Lys30, and Tyr32 of MTX adopted distinct interactions when associating with the IKCa channel. In addition, the residues Gln229, Ala230, Ala233, and Thr234 on the IKCa channel turret formed polar and non-polar interactions with MTX, whereas the turret of Kv1.2 was almost not involved in recognizing MTX. In all, the pairs of interacting residues on MTX and the IKCa channel of the bound complex indicated that electrostatic and Van der Waal interactions contributed equally to the formation of a stable MTX-IKCa complex, in contrast to the MTX-Kv1.2 binding that is dominantly mediated by electrostatic forces.Despite sharing similar pharmacological profiles toward both IKCa and Kv1.2 channels, MTX adopted totally diverging modes in the two association processes. All the molecular information unveiled here could not only offer a better understanding about the structural differences between the IKCa and Kv1.2 channels, but also provide novel structural clews that will help in the designing of more selective molecular probes to discriminate between these two channels.Scorpion venoms produce a large variety of peptide toxins that target ion channels [1-5]. Especially, the widespread use of scorpion-venom peptides acting on K+-channels as neuroscience tools and excellent ligand models has tremendously increased our knowledge in many fields, including exploration of the 3-dimensional structures and elucidation of the pharmacological characteristics of K+ channels [4,6-8]. In addition, peptide toxins are increasingly recognized as valuable sources of new drugs for channelopathies [9,10]. Although natural toxins often lack sufficient effic
Preparation and cytocompatibility of polylactic acid/hydroxyapatite/graphene oxide nanocomposite fibrous membrane
HaiBin Ma,WenXin Su,ZhiXin Tai,DongFei Sun,XingBin Yan,Bin Liu,QunJi Xue
Chinese Science Bulletin , 2012, DOI: 10.1007/s11434-012-5336-3
Abstract: A series of polylactic acid (PLA) based nanocomposite fibrous membranes, including neat PLA, PLA/hydroxyapatite (HA) and PLA/HA/graphene oxide (GO), were fabricated via electrospinning method. The morphology and composition were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) respectively. The thermal stability was determined by thermogravimetric analysis (TGA). To estimate the cytocompatibility of asprepared PLA/HA/GO fibrous membrane, MC3T3-E1 cells were cultured, and the corresponding cell adhesion and differentiation capability were investigated by fluorescence microscopy, SEM and MTT test. The electrospun ternary PLA/HA/GO membrane exhibited three-dimensional fibrous structure with relatively rough surface morphology, which made itself ideal for cell attachment and proliferation in bone tissue regeneration. The fluorescence microscopy, SEM and MTT test confirmed that the PLA/HA/GO nanocomposite fibrous membrane created a proper environment for the seeding and proliferation of MC3T3-E1 cells.
Nonlinear Electrical Properties of SnO2-Li2O-Nb2O5 Varistor System
Nonlinear Electrical Properties of SnO2—LiO—Nb2O5 Varistor System

Changpeng LI,Jinfeng WANG,Wenbin SU,Hongcun CHEN,Wenxin WANG,
ChangpengLI
,JinfengWANG

材料科学技术学报 , 2002,
Abstract: The electrical properties of (Nb, Li)-doped SnO2 ceramics as a new varistor material were investigated. The sample 97.95%SnO2.0.50%Li2O.0.05%Nb2O5 (mol fraction) sintered at 1450oC possess the highest density (r=6.77 g/cm3) and nonlinear electrical coefficient (a=11.6). The substitution of Sn4+with Li+ increases the concentration of oxygen vacancies, together with the formation of solid solution, which will increase the sintering rate greatly and decrease the optimized sintering temperature. The substitution of Sn4+with Li+ and the variation of temperature play very important effects on the densities, dielectric constant, nonlinear electrical properties and other characteristics of the samples. The properties of the grain boundary barrier and the microstructural characteristics were investigated to ensure the effect of the dopants and the temperature. A grain boundary defect barrier model was used to illustrate the grain boundary barriers formation in SnO2-Li2O-Nb2O5 varistors.
Unique Mechanism of the Interaction between Honey Bee Toxin TPNQ and rKir1.1 Potassium Channel Explored by Computational Simulations: Insights into the Relative Insensitivity of Channel towards Animal Toxins
Jun Hu, Su Qiu, Fan Yang, Zhijian Cao, Wenxin Li, Yingliang Wu
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0067213
Abstract: Background The 21-residue compact tertiapin-Q (TPNQ) toxin, a derivative of honey bee toxin tertiapin (TPN), is a potent blocker of inward-rectifier K+ channel subtype, rat Kir1.1 (rKir1.1) channel, and their interaction mechanism remains unclear. Principal Findings Based on the flexible feature of potassium channel turrets, a good starting rKir1.1 channel structure was modeled for the accessibility of rKir1.1 channel turrets to TPNQ toxin. In combination with experimental alanine scanning mutagenesis data, computational approaches were further used to obtain a reasonable TPNQ toxin-rKir1.1 channel complex structure, which was completely different from the known binding modes between animal toxins and potassium channels. TPNQ toxin mainly adopted its helical domain as the channel-interacting surface together with His12 as the pore-blocking residue. The important Gln13 residue mainly contacted channel residues near the selectivity filter, and Lys20 residue was surrounded by a polar “groove” formed by Arg118, Thr119, Glu123, and Asn124 in the channel turret. On the other hand, four turrets of rKir1.1 channel gathered to form a narrow pore entryway for TPNQ toxin recognition. The Phe146 and Phe148 residues in the channel pore region formed strong hydrophobic protrusions, and produced dominant nonpolar interactions with toxin residues. These specific structure features of rKir1.1 channel vestibule well matched the binding of potent TPNQ toxin, and likely restricted the binding of the classical animal toxins. Conclusions/Significance The TPNQ toxin-rKir1.1 channel complex structure not only revealed their unique interaction mechanism, but also would highlight the diverse animal toxin-potassium channel interactions, and elucidate the relative insensitivity of rKir1.1 channel towards animal toxins.
Potentiel d’adaptation du CECR dans les facultés de fran ais en Chine
Wang Wenxin
Synergies Europe , 2011,
Abstract: Depuis trois décennies, l’enseignement du fran ais a connu un essor dans les établissements d’enseignement supérieur de Chine. Le ministère chinois de l’Education, par les soins d’une commission spéciale, exerce sa tutelle sur les facultés de fran ais. Celles-ci doivent établir leurs cours conformément à un programme national et leurs étudiants sont incités à participer à un test national. Ce programme et ce test sont très peu connus des pays étrangers, encore moins que le CECR ne l’est des facultés chinoises. Or chacun a ses atouts : le programme chinois fut élaboré sur les caractéristiques des étudiants chinois et le besoin de l’Etat et veille dans une large mesure à construire des connaissances linguistiques, littéraires et culturelles, tandis que le CECR met son accent sur la formation de compétences communicatives. Les acteurs chinois du FLE auraient alors tout intérêt à renouveler le programme en s’inspirant des apports du CECR, et celui-ci, en revanche, ne pourrait parvenir à faire référence parmi les facultés de fran ais en Chine que par l’entremise de leur programme national.
Developing a Chinese Medicine programme in a western medical university
Wenxin Zhou
International e-Journal of Science, Medicine & Education , 2012,
Abstract: Chinese medicine is one of the most famoustraditional medicines in the world with a glorious andlong written history of at least 2000 years. Recently,acupuncture and the use of other herbal medicineare being gradually accepted globally. In 2011,the International Medical University (IMU) startedthe Chinese Medicine programme which is the first ofits kind in a western medicine university in Malaysia.The author introduced the background of Chinesemedicine and the curriculum of the Chinese Medicineprogramme established in IMU, analyzed the situationregarding the quality of lectures given by internal andexternal lecturers in this programme and also discussedon ways to integrate western and traditional medicine inIMU or in Malaysia. The launching of Chinese medicinein IMU is a great step in the development of IMU andalso an important step in the development of medicaleducation in Malaysia or even in South-east Asia.
Entanglement Entropy in Many-Fermion System
Wenxin Ding
Physics , 2009,
Abstract: In this four-part prospectus, we first give a brief introduction to the motivation for studying entanglement entropy and some recent development. Then follows a summary of our recent work about entanglement entropy in states with traditional long-range order. After that we demonstrate calculation of entanglement entropy in both one-dimensional spin-less fermionic systems as well as bosonic systems via different approaches, and connect them using one-dimensional bosonization. In the last part, we briefly sketch the idea of bosonization in high-dimensions, and discuss the possibility and advantage of approaching the scaling behavior of entanglement entropy of fermions in arbitrary dimensions via bosonization.
Bayesian variable selection for high dimensional generalized linear models: convergence rates of the fitted densities
Wenxin Jiang
Mathematics , 2007, DOI: 10.1214/009053607000000019
Abstract: Bayesian variable selection has gained much empirical success recently in a variety of applications when the number $K$ of explanatory variables $(x_1,...,x_K)$ is possibly much larger than the sample size $n$. For generalized linear models, if most of the $x_j$'s have very small effects on the response $y$, we show that it is possible to use Bayesian variable selection to reduce overfitting caused by the curse of dimensionality $K\gg n$. In this approach a suitable prior can be used to choose a few out of the many $x_j$'s to model $y$, so that the posterior will propose probability densities $p$ that are ``often close'' to the true density $p^*$ in some sense. The closeness can be described by a Hellinger distance between $p$ and $p^*$ that scales at a power very close to $n^{-1/2}$, which is the ``finite-dimensional rate'' corresponding to a low-dimensional situation. These findings extend some recent work of Jiang [Technical Report 05-02 (2005) Dept. Statistics, Northwestern Univ.] on consistency of Bayesian variable selection for binary classification.
Some Simple Formulas for Posterior Convergence Rates
Wenxin Jiang
Statistics , 2014, DOI: 10.1155/2014/469340
Abstract: We derive some simple relations that demonstrate how the posterior convergence rate is related to two driving factors: a "penalized divergence" of the prior, which measures the ability of the prior distribution to propose a nonnegligible set of working models to approximate the true model and a "norm complexity" of the prior, which measures the complexity of the prior support, weighted by the prior probability masses. These formulas are explicit and involve no essential assumptions and are easy to apply. We apply this approach to the case with model averaging and derive some useful oracle inequalities that can optimize the performance adaptively without knowing the true model.
SdPI, The First Functionally Characterized Kunitz-Type Trypsin Inhibitor from Scorpion Venom
Ruiming Zhao, Hui Dai, Su Qiu, Tian Li, Yawen He, Yibao Ma, Zongyun Chen, Yingliang Wu, Wenxin Li, Zhijian Cao
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0027548
Abstract: Background Kunitz-type venom peptides have been isolated from a wide variety of venomous animals. They usually have protease inhibitory activity or potassium channel blocking activity, which by virtue of the effects on predator animals are essential for the survival of venomous animals. However, no Kunitz-type peptides from scorpion venom have been functionally characterized. Principal Findings A new Kunitz-type venom peptide gene precursor, SdPI, was cloned and characterized from a venom gland cDNA library of the scorpion Lychas mucronatus. It codes for a signal peptide of 21 residues and a mature peptide of 59 residues. The mature SdPI peptide possesses a unique cysteine framework reticulated by three disulfide bridges, different from all reported Kunitz-type proteins. The recombinant SdPI peptide was functionally expressed. It showed trypsin inhibitory activity with high potency (Ki = 1.6×10?7 M) and thermostability. Conclusions The results illustrated that SdPI is a potent and stable serine protease inhibitor. Further mutagenesis and molecular dynamics simulation revealed that SdPI possesses a serine protease inhibitory active site similar to other Kunitz-type venom peptides. To our knowledge, SdPI is the first functionally characterized Kunitz-type trypsin inhibitor derived from scorpion venom, and it represents a new class of Kunitz-type venom peptides.
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