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Search Results: 1 - 10 of 166848 matches for " Li Qiang;Wu "
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Adaptive evolution of multiple-variable exons and structural diversity of drug-metabolizing enzymes
Can Li, Qiang Wu
BMC Evolutionary Biology , 2007, DOI: 10.1186/1471-2148-7-69
Abstract: We found that there are species-specific variable-exon duplications and mutations in the vertebrate Ugt1, Gcnt2, and Ugt2a clusters and that their variable and constant genomic organizations are conserved and vertebrate-specific. In addition, analyzing the complete repertoires of closely-related Ugt2 clusters in humans, mice, and rats revealed extensive lineage-specific duplications. In contrast to the Pcdh gene clusters, gene conversion does not play a predominant role in the evolution of the vertebrate Ugt1, Gcnt2 and Ugt2 gene clusters. Thus, their tremendous diversity is achieved through "birth-and-death" evolution. Comparative analyses and homologous modeling demonstrated that vertebrate UGT proteins have similar three-dimensional structures each with N-terminal and C-terminal Rossmann-fold domains binding acceptor and donor substrates, respectively. Molecular docking experiments identified key residues in donor and acceptor recognition and provided insight into the catalytic mechanism of UGT glucuronidation, suggesting the human UGT1A1 residue histidine 39 (H39) as a general base and the residue aspartic acid 151 (D151) as an important electron-transfer helper. In addition, we identified four hypervariable regions in the N-terminal Rossmann domain that form an acceptor-binding pocket. Finally, analyzing patterns of nonsynonymous and synonymous nucleotide substitutions identified codon sites that are subject to positive Darwinian selection at the molecular level. These diversified residues likely play an important role in recognition of myriad xenobiotics and endobiotics.Our results suggest that enormous diversity of vertebrate multiple variable first exons is achieved through birth-and-death evolution and that adaptive evolution of specific codon sites enhances vertebrate UGT diversity for defense against environmental agents. Our results also have interesting implications regarding the staggering molecular diversity required for chemical detoxification and dr
Application of mechanochemical synthesis of advanced materials
Hao Wu,Qiang Li
Journal of Advanced Ceramics , 2012, DOI: 10.1007/s40145-012-0012-2
Abstract: An overview is given of recent development of mechanochemical processes for the preparation of advanced ceramics. Some fundamental mechanical effects are firstly compared and discussed. Several important application fields are listed as follow, stemming from oxide materials, non-oxide materials, and composite materials to nano-structured materials.
Reform and Development of Educational Administration System in China
Qiang Li,Zhongyuan Wu
International Education Studies , 2008, DOI: 10.5539/ies.v1n3p136
Abstract: The paper mainly introduces the development of the educational administration agency in China, including the evolution of the educational administration agency, the Course of instituting legal system of education in China, the missions of the now Minister of Education, questions emerged in the development of the educational administration system, and measures taken to reform the educational administration system. By the description of the development of the educational administration system from Oct. 1949 to 1998, the questions of the educational administration system are pointed out and measures taken to resolve those questions are brought forward, as follow: to reconstruct the educational administration functions, to provide the opportunity for the citizens to participate in educational management, and to improve the legal system for education needs to strengthen the supervision and evaluation of education.
Order Topology and Frink Ideal Topology of Effect Algebras
Lei Qiang,Wu Junde,Li Ronglu
Physics , 2009,
Abstract: In this paper, the following results are proved: (1) $ $ If $E$ is a complete atomic lattice effect algebra, then $E$ is (o)-continuous iff $E$ is order-topological iff $E$ is totally order-disconnected iff $E$ is algebraic. (2) $ $ If $E$ is a complete atomic distributive lattice effect algebra, then its Frink ideal topology $\tau_{id}$ is Hausdorff topology and $\tau_{id}$ is finer than its order topology $\tau_{o}$, and $\tau_{id}=\tau_o$ iff 1 is finite iff every element of $E$ is finite iff $\tau_{id}$ and $\tau_o$ are both discrete topologies. (3) $ $ If $E$ is a complete (o)-continuous lattice effect algebra and the operation $\oplus$ is order topology $\tau_o$ continuous, then its order topology $\tau_{o}$ is Hausdorff topology. (4) $ $ If $E$ is a (o)-continuous complete atomic lattice effect algebra, then $\oplus$ is order topology continuous.
Research and Application of Code Automatic Generation Algorithm Based on Structured Flowchart  [PDF]
Xiang-Hu Wu, Ming-Cheng Qu, Zhi-Qiang Liu, Jian-Zhong Li
Journal of Software Engineering and Applications (JSEA) , 2011, DOI: 10.4236/jsea.2011.49062
Abstract: It is of great significance to automatically generate code from structured flowchart. There are some deficiencies in existing researches, and their key algorithms and technologies are not elaborated, also there are very few full-featured integrated development platforms that can generate code automatically based on structured flowchart. By analyzing the characteristics of structured flowchart, a structure identification algorithm for structured flowchart is put forward. The correctness of algorithm is verified by enumeration iteration. Then taking the identified flowchart as input, an automatic code generation algorithm is proposed. Also the correctness is verified by enumeration iteration. Finally an integrated development platform is developed using those algorithms, including flowchart modeling, code automatic generation, CDT\GCC\GDB etc. The correctness and effectiveness of algorithms proposed are verified through practical operations.
Effects of Arsenic Treatments on Saponin Content and Heterogeneity Extracted from Rhizome and Main Root of Panax notoginseng Plants Grown in Shaded Field  [PDF]
Yanqun Zu, Jinjin Sun, Ni Ma, Qiang Min, Guangquan Feng, Jiong Wu, Yuan Li
Journal of Geoscience and Environment Protection (GEP) , 2016, DOI: 10.4236/gep.2016.47003
Abstract: As contamination is one of important factors to Panax notoginseng quality and safety. Saponin is one of important compounds with the medicinal values of P. notoginseng. The impact of soil As on production of saponin of P. notoginseng knew very little. This study was performed to determine content and heterogeneity of saponins from P. notoginseng and its mechanisms upon treatments with different concentration levels of As in soil. Plants of P. notoginseng were treated with arsenic [As (V)] at 0, 20, 80, 140, 20 and 260 mg/kg concentration levels which were supplied as sodium arsenate (Na3AsO4). These experimental plants were grown in shade condition in a greenhouse. Plants were harvested at vigorous vegetative growth and fruit ripening stages, separately. Effects of As treatments on saponin content, and heterogeneity of monomers in the mixtures of notoginesenosides and ginsenosides, enzymatic activity and gene expression level of squalene synthetase were determined for rhizome and main root tissues. Results show that(1) Of all the As treatments from the lowest to the highest concentration levels, the As content in both rhizome and main roots from As-treated plants was within the standard level for superior products derived from P. notoginseng. The content of notoginsenosides from all tissues except the main roots at fruit ripening stage, was 5% higher than the standard level specified in the Chinese Pharmacopoeia; (2) The treatment of As at 20 mg/kg led to an 3.5% - 183.9% increases in total notoginesenosides content in rhizome and main roots, respectively. Treatments with the highest As concentration at 260 mg/kg resulted in a significant decline in total notoginsenosides content, and lower enzymatic activity and gene expression levels of squalene synthetase; (3) Under As treatment conditions, the ratio of Rb1/Rg1 decreased but the ratio of (Rb1 + Rg1)/R1 increased in both?rhizomes and main roots. Conclusively, this study demonstrated that low As concentration (20 - 80 mg/kg) treatments resulted in higher notoginsenoside content in P. notoginseng. However, treatments with high As concentrations had an adverse effect.
Computational Analysis of the Metal Free-Surface Instability, Fragmentation, and Ejecta under Shock  [PDF]
Jingsong Bai, Tao Wang, Jiaxin Xiao, Bing Wang, Han Chen, Lei Du, Xinzhu Li, Qiang Wu
World Journal of Mechanics (WJM) , 2017, DOI: 10.4236/wjm.2017.79021
Abstract: We conducted numerical simulations of the related processes of interface instability, tensile fragmentation, and jetting resulting from four kinds of typical macro defect perturbations (chevron, sine wave, rectangle, and square) on a Cu free surface under a reflected shock wave when Cu impacts a solid wall at a speed of 2.5 km/s and found that, for the chevron and sine wave cases, the ejecta velocities of the head are 6.28 and 5.88 km/s, respectively. Some parts of the inner material are in a tensile state without any fragmentation, which is observed only in the main body of the material owing to the tension effect. Furthermore, for the other two initial perturbations (rectangle and square), the highest ejecta velocities may even reach 9.14 and 9.59 km/s, respectively. Fragmentation caused by multilayer spallation can be observed on a large scale in the Cu main body, and there are granules in the front area of the ejecta but the degree to which fragmentation occurs is much less in the Cu main body and there is a notable high-speed, low-density granule area in the ejecta head. Finally, we present a detailed analysis of the spatial distribution of the granules, ejecta mass, pressure, temperature, and grid convergence.
The Influence of Different Contents of Bi Addition on the Corrosion Behavior of Various Zirconium-Based Alloys  [PDF]
Meiyi Yao, Xiaotong Wu, Wenrong Duan, Weipeng Zhang, Li Zhu, Linghong Zou, Jinlong Zhang, Qiang Li, Bangxin Zhou
Journal of Environmental Protection (JEP) , 2016, DOI: 10.4236/jep.2016.74044
Abstract:

Zr-4(Zr-1.5Sn-0.2Fe-0.1Cr,wt%), S5(Zr-0.8Sn-0.34Nb-0.39Fe-0.1Cr), T5(Zr-0.7Sn-1.07Nb-0.32Fe-0.08Cr) and Zr-1Nb were adopted to prepare Bi-containing zirconium alloys for systematically investigating the effect of Bi addition on the corrosion resistance of zirconium alloys. The specimens were corroded in superheated steam at 400/10.3 MPa, and in lithiated water with 0.01 M LiOH or in deionized water at 360/18.6 MPa by autoclave testing. Results show that the corrosion resistance increases with the increasing of Bi content dissolved in α-Zr. But the presence of Bi-con- taining second phase particles (SPPs) is unfavorable for the enhancement of corrosion resistance. This indicates that the Bi dissolved in α-Zr matrix plays an important role in improving the corrosion resistance, while the precipitation of the Bi-containing SPPs does harm to the corrosion resistance.

Zr(HSO4)4 as an efficient catalyst for the preparation of 10-aryl-6,8-dimethyl-6,10dihydro-5-oxa-6,8-diazaanthra[2,3-d][1,3]dioxole-7,9-diones under solvent-free conditions
Zhang, Jiangli;Li, Wei Lin;Wu, Li Qiang;
Journal of the Brazilian Chemical Society , 2011, DOI: 10.1590/S0103-50532011000700006
Abstract: a one-pot three-component condensation of 3,4-methylenedioxyphenol, aromatic aldehydes, and 1,3-dimethylbarbituric acid, efficiently promoted in the presence of zr(hso4)4 under solvent-free conditions, produced 10-aryl-6,8-dimethyl-6,10-dihydro-5-oxa-6,8-diazaanthra[2,3-d][1,3] dioxole-7,9-diones. the method offers several advantages including simple, easy and clean work-up procedure, relatively short reaction times and good to high yields of the products.
Alum-catalyzed one-pot synthesis of dihydropyrano[3,2-b]chromenediones
Li, Wei Lin;Wu, Li Qiang;Yan, Fu Lin;
Journal of the Brazilian Chemical Society , 2011, DOI: 10.1590/S0103-50532011001100025
Abstract: a simple, green and efficient solventless procedure for the synthesis of eleven dihydropyrano[3,2-b]chromenediones from the three-component condensation reaction of kojic acid, aromatic aldehydes, and dimedone using a reusable alum as catalyst is described.
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