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Now showing items 81 - 96 of 403

  • [IEEE 2009 WRI World Congress on Computer Science and Information Engineering - Los Angeles, California USA (2009.03.31-2009.04.2)] 2009 WRI World Congress on Computer Science and Information Engineering - The Design and Implementation of E-learning Support Service System Based on Learner Model

    Wang, Yanli   Cheng, Yun  

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  • [IEEE 2009 International Conference on New Trends in Information and Service Science (NISS) - Beijing, China (2009.06.30-2009.07.2)] 2009 International Conference on New Trends in Information and Service Science - Design and Implementation of WEB-Based Distance Teaching Support Platform for Rural Teachers

    Wang, Yanli   Cheng, Yun   Wang, Feng   Zheng, Zhongmei  

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  • SPIE Proceedings [SPIE Third International Symposium on Multispectral Image Processing and Pattern Recognition - Beijing, China (Monday 20 October 2003)] Third International Symposium on Multispectral Image Processing and Pattern Recognition - Scene matching navigation based on multisensor image fusion

    Wang, Yanli   Chen, Zhe   Lu, Hanqing   Zhang, Tianxu  

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  • A dummy molecularly imprinted solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry for selective determination of four pyridine carboxylic acid herbicides in milk

    Tan, Sijia   Yu, Hailong   He, Yahui   Wang, Miao   Liu, Guiqiao   Hong, Sihui   Yan, Feiyan   Wang, Yanli   Wang, MengQiang   Li, Tengfei   Wang, Jing   Abd EI-Aty, A.M.   Hacımüftüoğlu, Ahmet   She, Yongxin  

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  • Nitrogen-doped carbon nanotubes synthesized with carbon nanotubes as catalyst

    Wang, Can   Huang, Zhenghong   Zhan, Liang   Wang, Yanli   Qiao, Wenming   Liang, Xiaoyi   Ling, Licheng  

    Nitrogen-doped carbon (CN(x)) nanotubes were synthesized with carbon nanotubes (CNTs) as catalyst by detonation-assisted chemical vapor deposition. CN(x) nanotubes exhibited compartmentalized bamboo-like structure. Electron energy loss spectroscopy and elemental mapping studies indicated that the synthesized tubes contained high concentration of nitrogen (ca. 17.3 at.%). inhomogeneously distributed with an enrichment of nitrogen within the compartments. X-ray photoelectron spectroscopy analysis revealed the presence of pyridine-like N and graphitic N incorporated into the graphitic network. The catalytic activity of CNTs for CN(x) nanotube growth was ascribed to the nanocurvature and opening edges of CNT tips, which adsorbed C(n)/CN species and assembled them into CN(x) nanotubes. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.
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  • Binary Classification of Aqueous Solubility Using Support Vector Machines with Reduction and Recombination Feature Selection RID A-5344-2010

    Cheng, Tiejun   Li, Qingliang   Wang, Yanli   Bryant, Stephen H.  

    Aqueous solubility is recognized as a critical parameter in both the early- and late-stage drug discovery. Therefore, in silico modeling of solubility has attracted extensive interests in recent years. Most previous studies have been limited in using relatively small data sets with limited diversity, which in turn limits the predictability of derived models. In this work, we present a support vector machines model for the binary classification of solubility by taking advantage of the largest known public data set that contains over 46 000 compounds with experimental solubility. Our model was optimized in combination with a reduction and recombination feature selection strategy. The best model demonstrated robust performance in both cross-validation and prediction of two independent test sets, indicating it could be a practical tool to select soluble compounds for screening, purchasing, and synthesizing. Moreover, our work may be used for comparative evaluation of solubility classification studies ascribe to the use of completely public resources.
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  • Electronic structures of silicene/GaS heterosheets

    Ding, Yi   Wang, Yanli  

    Although Dirac-like electronic properties are predicted for silicene, recent experiments find substrate-induced complex bucklings would destruct such feature [C.-L. Lin et al., Phys. Rev. Lett. 110, 076801 (2013)]. Here, using first-principles calculations, we propose that the recently synthesized gallium sulfide (GaS) nanosheet could be an appropriate substrate for silicene, which can form commensurate Si/GaS heterosheets akin to graphene/BN systems. More importantly, in these heterosheets, the characteristic Dirac-like band feature of linear dispersions is retained, and due to the intrinsic electric field, a sizable band gap is opened at the Dirac point, which could be further tuned by bias voltage or strains. (C) 2013 AIP Publishing LLC.
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  • Intrinsic ferromagnetism and valley polarization in hydrogenated group V transition-metal dinitride (MN 2 H 2 , M = V/Nb/Ta) nanosheets: insights from first-principles

    Ding, Yi   Wang, Yanli  

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  • FUNCTIONALIZED MULTIWALLED CARBON NANOTUBES BY GRAFTING HYPERBRANCHED POLYSILOXANE

    Yan, Hongxia   Jia, Yuan   Ma, Lei   Wang, Yanli  

    Multi-walled carbon nanotubes (MWCNTs) are grafted with hyperbranched polysiloxane (HBPSi) by an efficient hydrosilylation method. In this hydrosilylation process, hydroxylated MWCNTs (HO-MWCNTs) are first functionalized by triethoxyvinylsilane to introduce carbon-carbon double bonds (C=C) on the surface of MWCNTs. The C=C is then reacted with the monomer of methylbis(dimethylvinylsiloxy) silane in the presence of the platinum-carbon catalyst, thus HBPSi is ultimately grafted on the surface of MWCNTs. Fourier transform infrared spectrometry (FTIR), Transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) are employed to characterize the changes in MWCNTs surface morphology, chemistry and physical conditions at different processing stages. The content of HBPSi on the surface of MWCNTs was also measured by the thermogravimetric analysis (TGA). The results indicate that the HBPSi successfully grafted on the surface of MWCNTs, and the dispersion of MWCNTs in organic solvent is also improved after functionalization.
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  • Unusual structural and electronic properties of porous silicene and germanene: insights from first-principles calculations

    Ding, Yi   Wang, Yanli  

    Using first-principles calculations, we investigate the geometric structures and electronic properties of porous silicene and germanene nanosheets, which are the Si and Ge analogues of alpha-graphyne (referred to as silicyne and germanyne). It is found that the elemental silicyne and germanyne sheets are energetically unfavourable. However, after the C-substitution, the hybrid graphyne-like sheets (c-silicyne/c-germanyne) possess robust energetic and dynamical stabilities. Different from silicene and germanene, c-silicyne is a flat sheet, and c-germanyne is buckled with a distinct half-hilled conformation. Such asymmetric buckling structure causes the semiconducting behaviour into c-germanyne. While in c-silicyne, the semimetallic Dirac-like property is kept at the nonmagnetic state, but a spontaneous antiferromagnetism produces the massive Dirac fermions and opens a sizeable gap between Dirac cones. A tensile strain can further enhance the antiferromagnetism, which also linearly modulates the gap value without altering the direct-bandgap feature. Through strain engineering, c-silicyne can form a type-II band alignment with the MoS2 sheet. The combined c-silicyne/MoS2 nanostructure has a high power conversion efficiency beyond 20% for photovoltaic solar cells, enabling a fascinating utilization in the fields of solar energy and nano-devices.
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  • Membrane protein profiling of Acidovorax avenae subsp. avenae under various growth conditions.

    Li, Bin   Wang, Li   Ibrahim, Muhammad   Ge, Mengyu   Wang, Yanli   Mannan, Shazia   Asif, Muhammad   Sun, Guochang  

    Membrane proteins (MPs) of plant pathogenic bacteria have been reported to be able to regulate many essential cellular processes associated with plant disease. The aim of the current study was to examine and compare the expression of MPs of the rice bacterial pathogen Acidovorax avenae subsp. avenae strain RS-1 under Luria-Bertani (LB) medium, M9 medium, in vivo rice plant conditions and leaf extract (LE) medium mimicking in vivo plant condition. Proteomic analysis identified 95, 72, 75, and 87 MPs under LB, in vivo, M9 and LE conditions, respectively. Among them, six proteins were shared under all tested growth conditions designated as abundant class of proteins. Twenty-six and 21 proteins were expressed uniquely under in vivo versus LB medium and LE versus M9 medium, respectively, with 17 proteins common among these uniquely induced proteins. Moreover, most of the shared proteins are mainly related to energy metabolism, transport of small molecules, protein synthesis and secretion as well as virulence such as NADH, OmpA, secretion proteins. Therefore, the result of this study not only suggests that it may be an alternate method to analyze the in vivo expression of proteins by using LE medium to mimic plant conditions, but also reveals that the two sets of differentially expressed MPs, in particular the common MPs between them, might be important in energy metabolism, stress response and virulence of A. avenae subsp. avenae strain RS-1. =20
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  • Diversification and evolution of the avirulence gene AVR-Pita1 in field isolates of Magnaporthe oryzae

    Dai, Yuntao   Jia, Yulin   Correll, James   Wang, Xueyan   Wang, Yanli  

    Rice blast disease is the single most destructive plant disease that threatens stable rice production worldwide Race-specific resistance to the rice blast pathogen has not been durable and the mechanism by which the resistance is overcome remains largely unknown Here we report the molecular mechanisms of diversification and the instability of the avirulence gene AVR Pita1 in field strains of Magnaporthe oryzae interacting with the host resistance gene Pi to and triggering race-specific resistance Two-base pair insertions resulting in frame-shift mutations and partial and complete deletions of AVR-Pita1 were identified in virulent isolates Moreover a total of 38 AVR-Pita1 haplotypes encoding 27 AVR-Pita1 variants were identified among 151 avirulent isolates Most DNA sequence variation was found to occur in the exon region resulting in amino acid substitution These findings demonstrate that AVR-Pita1 is under positive selection and mutations of AVR-Pita1 are responsible for defeating race-specific resistance in nature Published by Elsevier Inc
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  • Nucleation, propagation and cleavage of target RNAs in Ago silencing complexes RID G-3306-2010

    Wang, Yanli   Juranek, Stefan   Li, Haitao   Sheng, Gang   Wardle, Greg S.   Tuschl, Thomas   Patel, Dinshaw J.  

    The slicer activity of the RNA-induced silencing complex resides within its Argonaute (Ago) component, in which the PIWI domain provides the catalytic residues governing guide-strand mediated site-specific cleavage of target RNA. Here we report on structures of ternary complexes of Thermus thermophilus Ago catalytic mutants with 5'-phosphorylated 21-nucleotide guide DNA and complementary target RNAs of 12, 15 and 19 nucleotides in length, which define the molecular basis for Mg(2+)-facilitated site-specific cleavage of the target. We observe pivot-like domain movements within the Ago scaffold on proceeding from nucleation to propagation steps of guide-target duplex formation, with duplex zippering beyond one turn of the helix requiring the release of the 3'-end of the guide from the PAZ pocket. Cleavage assays on targets of various lengths supported this model, and sugar-phosphate-backbone-modified target strands showed the importance of structural and catalytic divalent metal ions observed in the crystal structures.
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  • Supported ammonium metatungstate as highly efficient catalysts for the vapour-phase O-methylation of catechol with methanol

    Zhu, Xiaomei   Li, Xuemei   Zou, Xiujing   Wang, Yanli   Jia, Mingjun   Zhang, Wenxiang  

    Ammonium metatungstate (AMT) impregnated SiO2, TiO2 and Al2O3 catalysts were found to be highly active and selective for the vapour-phase O-methylation of catechol with methanol. Particularly, the AMT/SiO2 catalyst with 7.9 wt% W content showed the highest catechol conversion (97.1%) and the highest guaiacol yield (88.1%). (c) 2006 Elsevier B.V. All rights reserved.
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  • Early Time Excited-State Structural Evolution of Pyranine in Methanol Revealed by Femtosecond Stimulated Raman Spectroscopy

    Wang, Yanli   Liu, Weimin   Tang, Longteng   Oscar, Breland   Han, Fangyuan   Fang, Chong  

    To understand chemical reactivity of molecules in condensed phase in real time, a structural dynamics technique capable of monitoring molecular conformational motions on their intrinsic time scales, typically on femtoseconds to picoseconds, is needed. We have studied a strong photoacid pyranine (8-hydroxypyrene-1,3,6-trisulfonic acid, HPTS, pK(a)* approximate to 0) in pure methanol and observed that excited-state proton transfer (ESPT) is absent, in sharp contrast with our previous work on HPTS in aqueous solutions wherein ESPT prevails following photoexcitation. Two transient vibrational marker 0 2 bands at similar to 4477 (1454) and 1532 (1528) cm appear in CH3OH (CD3OD), respectively, rising within the instrument response time of similar to 140 fs and decaying with 390-470 (490-1400) fs and similar to 200 ps time constants in CH3OH (CD3OD). We attribute the mode onset to small-scale coherent proton motion along the pre-existing H-bonding chain between HPTS and methanol, and the two decay stages to the low-frequency skeletal motion-modulated Franck-Condon relaxation within similar to 1 ps and subsequent rotational diffusion of H-bonding partners in solution before fluorescence. The early time kinetic isotope effect (KIE) of similar to 3 upon methanol deuteration argues active proton motions particularly within the first few picoseconds when coherent skeletal motions are underdamped. Pronounced quantum beats are observed for high-frequency modes consisting of strong phenolic COH rocking (1532 cm(-1)) or H-out-of-plane wagging motions (952 cm(-1)) due to anharmonic coupling to coherent low-frequency modes impulsively excited at ca. 96, 120, and 168 cm(-1). The vivid illustration of atomic motions of HPTS in varying H-bonding geometry with neighboring methanol molecules unravels the multidimensional energy relaxation pathways immediately following photoexcitation, and provides compelling evidence that, in lieu of ESPT, the photoacidity of HPTS promptly activates characteristic low-frequency skeletal motions to search phase space mainly concerning the phenolic end and to efficiently dissipate vibrational energy via skeletal deformation and proton shuttling motions within the intermediate, relatively confined excited-state HPTS-methanol complex on a solvent-dependent dynamic potential energy surface.
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  • C2c1-sgRNA Complex Structure Reveals RNA-Guided DNA Cleavage Mechanism

    Liu, Liang   Chen, Peng   Wang, Min   Li, Xueyan   Wang, Jiuyu   Yin, Maolu   Wang, Yanli  

    C2c1 is a type V-B CRISPR-Cas system dual-RNAguided DNA endonuclease. Here, we report the crystal structure of Alicyclobacillus acidoterrestris C2c1 in complex with a chimeric single-molecule guide RNA ( sgRNA). AacC2c1 exhibits a bi-lobed architecture consisting of a REC and NUC lobe. The sgRNA scaffold forms a tetra-helical structure, distinct from previous predictions. The crRNA is located in the central channel of C2c1, and the tracrRNA resides in an external surface groove. Although AacC2c1 lacks a PAM-interacting domain, our analysis revealed that the PAM duplex has a similar binding position found in Cpf1. Importantly, C2c1-sgRNA system is highly sensitive to singlenucleotide mismatches between guide RNA and target DNA. The resulting reduction in off-target cleavage renders C2c1 a valuable addition to the current arsenal of genome-editing tools. Together, our findings indicate that sgRNA assembly is achieved through a mechanism distinct from that reported previously for Cas9 or Cpf1 endonucleases.
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