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Search Results: 1 - 10 of 104377 matches for " Guoxin Zhang "
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Genetic Engineering Peanut for Higher Drought- and Salt-Tolerance  [PDF]
Li Sun, Rongbin Hu, Guoxin Shen, Hong Zhang
Food and Nutrition Sciences (FNS) , 2013, DOI: 10.4236/fns.2013.46A001
Abstract: Peanut (Arachis hypogaea L.) is one of the major oilseed crops, mainly grown in tropical and sub-tropical regions of the world. It is also rich in proteins, vitamins and ions, therefore it constitutes an important portion of food nutrition for people in these regions. The production of peanut is being threatened by the changing environments as the major peanut producing counties such as China, India, and USA are facing severe water shortage for peanut irrigation. The yield and quality of peanut are negatively affected by drought and salinity. Making peanut more droughtand salt-tolerant will likely sustain peanut production in countries where water shortage or saline soil are already problems. Efforts were made to genetically engineer peanut for higher tolerance to drought and salt. Analysis of these transgenic peanut plants indicated that the agronomic traits such as peanut yields were the same between wild-type and transgenic peanut plants under normal growth conditions, yet the yields of transgenic peanut plants were much higher than wild-type peanut plant under reduced irrigation conditions. Other traits such as protein content and fatty acid compositions in the seeds of transgenic peanut plants were not altered under both normal and drought conditions, indicating that the genetic manipulation of peanut for stress tolerance did not affect chemical compositions of peanut seeds in transgenic peanut plants, only increased seed yields under stress conditions.
Mesoporous zeolite SBA-15 supported nickel diimine catalysts for ethylene polymerization
Chao Guo,Dao Zhang,Guoxin Jin
Chinese Science Bulletin , 2004, DOI: 10.1007/BF03182807
Abstract: The novel mesoporous zeolite SBA-15 is successfully used as the support to immobilize late-transition metal nickel diimine catalyst, both in physical and chemical methods, EA, ICP, FT-IR and XRD are applied to characterizing these supported catalysts. The results of ethylene polymerization reveal that these supported catalysts have high catalytic activity as their homogenous counterpart does, moreover, polyethylene with a fibrous morphology is produced due to the channel effect of support, and both the molecular weight and molecular weight distributions of polymers are increased greatly.
Half-sandwich β-diketonato complexes of zirconium and their application as catalysts to ethylene polymerization
Jun Zhang,Guangrong Tang,Guoxin Jin
Chinese Science Bulletin , 2006, DOI: 10.1007/s11434-006-2182-1
Abstract: The bis(β-diketonato) Zr complexes CpZr(acac)2Cl (acac = acetylacetonato) (1) and Cp*Zr(acac)2Cl (2) can be synthesized by the reaction of Cp′ZrCl3(Cp′ = Cp or Cp*) with 2 equiv of lithium acetylacetonate. CpZr(acac)2Cl (1) can be quantitatively prepared by treatment of Cp2ZrCl2 with excess acetylacetone. The tris(β-diketonato) Zr complex CpZr(tfac)3 (tfac = trisfluoroacetylacetonato) (3) has been prepared by treatment of CpZrCl3 with sodium trisfluoroacetylacetonate. The replacement of both chlorine atoms and one Cp group from zirconocene dichloride by nonfluorinated diketone, acetylacetone, readily occurs at room temperature in triethylamine medium, offering the tris(β-diketonato) Zr complex CpZr(acac)3 (4). The complexes were characterized by 1H NMR spectroscopic methods. In addition, the molecular structures of complexes 3 and 4 have been determined by X-ray diffraction methods. When activated by excess methylaluminoxane (MAO), these complexes were active for ethylene polymerization, offering polyethylenes with high molecular weights and narrow molecular weight distributions. Complex 4 showed a very high ethylene polymerization activity of up to 7100 kg PE/mol Zr·h at 5 atm. Complexes 1 and 2 were also active for ethylene/1-hexene copolymerization.
Session Communication and Integration
Guoxin Su,Mingsheng Ying,Chengqi Zhang
Computer Science , 2012,
Abstract: The scenario-based specification of a large distributed system is usually naturally decomposed into various modules. The integration of specification modules contrasts to the parallel composition of program components, and includes various ways such as scenario concatenation, choice, and nesting. The recent development of multiparty session types for process calculi provides useful techniques to accommodate the protocol modularisation, by encoding fragments of communication protocols in the usage of private channels for a class of agents. In this paper, we extend forgoing session type theories by enhancing the session integration mechanism. More specifically, we propose a novel synchronous multiparty session type theory, in which sessions are separated into the communicating and integrating levels. Communicating sessions record the message-based communications between multiple agents, whilst integrating sessions describe the integration of communicating ones. A two-level session type system is developed for pi-calculus with syntactic primitives for session establishment, and several key properties of the type system are studied. Applying the theory to system description, we show that a channel safety property and a session conformance property can be analysed. Also, to improve the utility of the theory, a process slicing method is used to help identify the violated sessions in the type checking.
Requirement of Osteopontin in the migration and protection against Taxol-induced apoptosis via the ATX-LPA axis in SGC7901 cells
Rihua Zhang, Jing Wang, Shijie Ma, Zuhu Huang, Guoxin Zhang
BMC Cell Biology , 2011, DOI: 10.1186/1471-2121-12-11
Abstract: In comparison with non-treated cells, we found that the ATX-LPA axis up-regulated OPN expression by 1.92-fold in protein levels and 1.3-fold in mRNA levels. The ATX-LPA axis activates LPA2, Akt, ERK and ELK-1 and also protects SGC7901 cells from apoptosis induced by Taxol treatment.This study provides the first evidence that expression of OPN induced by ATX-LPA axis is mediated by the activation of Akt and MAPK/ERK pathways through the LPA2 receptor. In addition, OPN is required for the protective effects of ATX-LPA against Taxol-induced apoptosis and ATX-LPA-induced migration of SGC7901 cells.Autotaxin (ATX), also known as phosphodiesterase-I alpha (PD-I alpha) or ecto-nucleotide pyrophosphatase/phosphodiesterase 2 (NPP2 or ENPP2), is overexpressed in various tumors, including gastric cancer, ovarian cancer [1], breast cancer [2]. ATX has lysophospholipase D (lysoPLD) activity, which converts lysophosphatidylcholine (LPC) into lysophosphatidic acid (LPA) [3]. LPA levels have been reported to be elevated in diverse physiological and pathological conditions including pregnancy, high cholesterol diet, and ovarian cancer [4]. The biological outcome of ATX activity depends on the local availability of its substrate LPC [5]. The ATX-LPA signaling axis has been implicated in angiogenesis, chronic inflammation, fibrotic diseases and tumor progression, making this system an attractive target for therapy [6]. LPA elicits a variety of cellular biological responses through LPA receptors, which are a family of seven-transmembrane G protein-coupled receptors (GPCRs), including LPA1, LPA2, LPA3, and LPA4 [7]. LPA1-LPA3 receptors are expressed in various combinations in almost every tissue throughout the body, while LPA4 receptor is not widely expressed in human tissues [8]. LPA enhances the migration of gastric cancer cells by mediating the location of RhoA [9].Osteopontin (OPN), a glycophosphoprotein cytokine, plays an important role in both physiological and pathological proces
Zircon U-Pb age of granitic gneiss on Duku highway in western Tianshan of China and its geological implications
Yibing Chen,Aiqin Hu,Guoxin Zhang,Qianfeng Zhang
Chinese Science Bulletin , 2000, DOI: 10.1007/BF02886044
Abstract: Granitic gneiss on Duku highway in western Tianshan has been dated by the U-Pb zircon method. When plotted on the concordia diagram, the results give linear data array and the upper intercept age of (882 ± 33)Ma, and the age was considered as the crystallization age of the protolith. Granitic gneiss has high ASI value (1.09), high LILE and LREE contents, significantly negative Eu depletion, distinctly negative Ba, Sr, P, Ti and Nb anomalies and indicate continental crust parentage, which is consistent with high initial87Sr/86Sr ratios value (0.7170) and very negative εNd(t)=-14.1. The protolith magma is interpreted as a product of partial melting of the basement rocks of older basement crust.
Zircon U-Pb age of granitic gneiss on Duku highway in western Tianshan of China and its geological implications

CHEN Yibing,HU Aiqin,ZHANG Guoxin,ZHANG Qianfeng,

科学通报(英文版) , 2000,
Abstract: Granitic gneiss on Duku highway in western Tianshan has been dated by the U-Pb zircon method. When plotted on the concordia diagram, the results give linear data array and the upper intercept age of (882 ± 33)Ma, and the age was considered as the crystallization age of the protolith. Granitic gneiss has high ASI value (1.09), high LILE and LREE contents, significantly negative Eu depletion, distinctly negative Ba, Sr, P, Ti and Nb anomalies and indicate continental crust parentage, which is consistent with high initial87Sr/86Sr ratios value (0.7170) and very negative εNd(t)=-14.1. The protolith magma is interpreted as a product of partial melting of the basement rocks of older basement crust.
A Self-Similar Call Admission Control Algorithm in WiMAX  [PDF]
Yongdong Hu, Guoxin Wu
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2016, DOI: 10.4236/ijcns.2016.95016
Abstract:

Modelling WiMAX network traffic based on the self-similarity character is better than the traditional model based on the Poisson process, because the former can provide more accurate calculation for effective bandwidth. In this paper we propose a WiMAX network traffic model based on M/Pareto model to describe its self-similarity character. Then we deduce the average transmission rate and the variance coefficient for the FBM traffic model by the M/Pareto model, and get the Hurst parameter of the FBM traffic model by statistical analysis method. By the FBM traffic model we get a formula for calculating the effective bandwidth. Accordingly, we propose a modified self-similar call admission control algorithm (SS-CAC). SS-CAC can avoid measuring the parameter values of FBM traffic flow to do call admission control. Simulation results show that SS-CAC greatly reduces the call blocking rate and improves the bandwidth utilization.

Synthesis and characterization of organometallic macrocyclic rhodium (III) complex with pyrazine ligands
Jianqiang Wang,Zheng Zhang,Linhong Weng,Guoxin Jin
Chinese Science Bulletin , 2004, DOI: 10.1360/04wb0040
Abstract: The reaction of half-sandwich complex (Cptt Rh)2Cl2(μ-Cl)2 (1) (Cptt=η5 tBu2C5H3) with 1 equiv. of Ag-SO3CF3 in CH2Cl2 affords tri-μ-chloro dirhodium (2) cation compound, with 2 equiv. of AgSO3CF3 providing di-μ-chloro complex 3. The reaction of 3 with pyrazine gives a novel tetra-nuclear 14-member organometallic macrocyclic complex 4. FT-IR, 1H-NMR, and EA were used to characterize these complexes. The structures of complexes 2 and 4 are confirmed by X-ray analysis. In complex 2, the two Cptt ring and tri-chloro atoms faces are approximately parallel to each other. In complex 4, the complex cation has a rectangular cavity with the dimension of 0.3748 nm×0.7027 nm, and the two-pyrazine rings are parallel to each other with a distance of 0.3510 nm.
SECOND-ORDER MANIFOLD METHOD IN STRUCTURE FAILURE ANALYSIS
二阶流形元法与结构变形分析

Zhang Guoxin,Peng Jing,
张国新
,彭静

力学学报 , 2002,
Abstract: Manifold method (MM) is a newly developed numerical procedure. The method possesses three features. (1) It uses two sets of meshes, namely mathematics meshes and physical meshes. Mathematical meshes are used to define interpolation function. Physical meshes are used to define physical boundary and integration domain. (2) The concept of cover is utilized. Local function at each zone is defined at cover. Each cover coves an enclosed zone. Covers overlap each other and define the global function of the common zone by a weight function. (3) It uses penalty as contact treatment. A unique contact treatment method is developed. By this sort of treating the contact between blocks are able to simulate reasonably. All these features make MM not only be able to accurately analyze the structure failure and stress distribution as FEM, but also to obtain integrally the deformation and block movement of discontinuities as DDA. Based on the original first-order MM by Shi, this paper presents a second-order MM with detail computational formula, governing equations and numerical codes. Application examples include normal stress distribution and deformation problem, large-scale deformation problem and contact problem. The simulation results are compared with analytical solutions. It shows that the newly developed second-order MM is capable of analyzing structure stress distribution and contact stress problems with relatively high accuracy. A simulation example of slope failure is also given in the paper. Reasonable failure process is obtained. The extended second order manifold method has good adaptability and can be used to simulate the whole process of structure from loading and deformation to failure and movement of blocks.
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