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A Novel Chemical Oscillator with Tyrosine as the substrate

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Chinese Chemical Letters 2003年第12期14卷 1281-1284页

作者： Wu YANG Jie REN Jin Zhang GAO Hua YANG Dong Yu Lv Xiu Hui LIU Institute of Chemistry Northwest Normal UniversityLanzhou 730070

A new chemical oscillating reaction system involving the manganese(II)-catalyzed reaction among potassium bromate, acetone and tyrosine in acidic medium was described in this paper. The apparent activation energy of the induction period (Ein) and that of oscillation period (Ep) were calculated, Ein=110.61KJ/mol, Ep=159.41KJ/mol. The optimum concentration of each reactant was investigated and a steady chemical oscillating system was obtained.

关键词： Chemical oscillator tyrosine substrate mechanism.

Selection of substrate recognition sequence of protein kinase with ferric chelation affinity chromatography

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Science China(Life Sciences) 1997年第2期40卷 184-193页

作者：陈长征夏其昌李伯良王应睐 Shanghai Institute of Biochemistry Chinese Academy of Sciences Shanghai 200031 China

Protein kinase substrate phage (PKS phage) was constructed by fusing the substrate recognition consensus sequence of cAMP-dependent protein kinase (cAPK) with bacteriophage minor coat protein g3p and by dis-playing it on the surface of filamentous bacteriophage fd. Phosphorylation in vitro by cAPK showed a unique labelled band of approximately 60 ku, which was consistent with the molecular weight of the PKS-g3p fusion protein. Some weakly phosphorylated bands for both PKS phage and wild-type phage were also observed. Phage display random 15-mer peptide library phosphorylated by cAPK was selected with ferric (Fe3+ ) chelalion affinity resin. After 4 rounds of screening, phage clones were picked out to determine the displayed peptide sequences by DNA sequencing. The results showed that 5 of 14 sequenced phages displayed the cAPK recognition sequence motif (R)RXS/T. Their in vitro phosphorylation analyses revealed the specific labelled bands corresponding to the positive PKS phages with and without the typical (R)RXS/T sequence motif. It suggested that the new method of using ferric (Fe 3+ ) chelation affinity chromatography to identify the substrate specificity of protein kinase from random peptide library was feasible.

关键词： protein kinase enzyme substrate phage display peptide library metal ion chelation affinity chromatography.

Effect of substrate-Water Interaction on the Wetting Behavior in Water-Oil and substrate-Water-Oil Systems

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Wuhan University Journal of Natural Sciences 2003年第04A期8卷 1097-1102页

作者： Yuan Yin-quan 1,2 , Zou Xian-wu 1 , Jin Zhun-zhi 1 1. School of Physics and Technology, Wuhan University, Wuhan 430072, Hubei, China 2. Department of Physics, Xiaogan University, Xiaogan 432100, Hubei, China School of Physics and Technology Wuhan University Wuhan Hubei China Department of Physics Xiaogan University Xiaogan Hubei China

The effects of the substrate-water interaction on the wetting behavior in water-oil and surfactant-water-oil systems confined by one substrate which has the preferential interaction to one species of particles have been investigated by using the free energy analysis and discontinuous molecular dynamic simulations. As the preferential interaction between the substrate and water particles varies from small repulsion to large attraction, the partial drying, partial wetting and complete wetting state are observed in sequence. In addition, the wetting behavior of surfactant aqueous solution on the substrate is not only dependent on the interaction, but also limited by the maximum equilibrium concentration of surfactants at the interface.

关键词： wetting behavior wetting transition preferential interaction substrate

substrate availability and toxicity shape the structure of microbial communities engaged in metabolic division of labor

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mLife 2022年第2期1卷 131-145页

作者： Miaoxiao Wang Xiaoli Chen Yue-Qin Tang Yong Nie Xiao-Lei Wu Department of Energy&Resources Engineering College of EngineeringPeking UniversityBeijingChina Department of Environmental Systems Science ETH ZurichZürichSwitzerland Department of Environmental Microbiology EawagDübendorfSwitzerland Department of Environmental Science and Engineering College of Architecture and EnvironmentSichuan UniversityChengduChina Institute of Ocean Research Peking UniversityBeijingChina Institute of Ecology Peking UniversityBeijingChina

Metabolic division of labor(MDOL)represents a widespread natural phenomenon,whereby a complex metabolic pathway is shared between different strains within a community in a mutually beneficial ***,little is known about how the composition of such a microbial community is *** hypothesized that when degradation of an organic compound is carried out via MDOL,the concentration and toxicity of the substrate modulate the benefit allocation between the two microbial populations,thus affecting the structure of this *** tested this hypothesis by combining modeling with experiments using a synthetic *** modeling analysis suggests that the proportion of the population executing the first metabolic step can be simply estimated by Monod-like formulas governed by substrate concentration and *** model and the proposed formula were able to quantitatively predict the structure of our synthetic *** analysis demonstrates that our rule is also applicable in estimating community structures in spatially structured ***,our work clearly demonstrates that the structure of MDOL communities can be quantitatively predicted using available information on environmental factors,thus providing novel insights into how to manage artificial microbial systems for the wide application of the bioindustry.

关键词： community structure mathematical model metabolic division of labor substrate synthetic microbial consortium

Studies of substrate binding region of mEAAC1 and mASCT1 by constructing chimeras

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Chinese Science Bulletin 1999年第6期44卷 524-528页

作者： Jing Li Jibin Peng Jian Fei Fang Huang Quanbao Gu Lihe Guo Chinese Acad Sci Shanghai Inst Cell Biol Mol Cell Biol Lab Shanghai 200031 Peoples R China

The cDNA chimeras between two subtypes of mouse excitatory amino acid transporter family, mouse excitatory amino acid carrier 1 （mEAAC1） and mouse alanine serine cysteine transporter 1 （mASCT1）, were constructed by recombinant PCR. After transcription in vitro, the cRNA was injected and expressed in Xenopus laevis oocytes. 3H-Glu and 3H-Ser were used as isotopic tracer to measure the flux of amino acids. The results showed that there might not be the key amino acids responsible for substractive specificity in the NH2-terminal and its adjacent regions of these two transporters, which probably supported the formation of the substrata binding sites.

关键词： mEAAC1 mASCT1 chimeras substrate binding region.

CATALYTIC ACTIVITIES OF substrate METALS IN A Ni-B-SiC ELECTROLESS COMPOSITE BATH

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中国有色金属学会会刊：英文版 1993年第2期3卷 36-40页

作者： Yu,Xinwei Anshan Institute of Iron and Steel Technology,Anshan 114002,ChinaZhao,Guopeng University of Science and Technology Beijing,Beijing 100083,ChinaWang,Fengyin Wang,Guobin Northeast University of Technology,Shenyang 110000,China

The catalytic activities of different substrate metals in Ni-B-SiC electroless composite bath was investigatedby means of measuring stationary potentials,potential-time curves and *** mechanism of electrolessplating taking place in the substrate metals at initial stage was *** results showed:(1)Inaddition to the stationary potential of the substrate metal and the temperature of the bath,the change of the sur-face state of metal,e.g.,its passivity,is one of the factors for deciding catalytic activity of a substrate metal.(2)the transition time is helpful in determines the degree of catalytic activity.(3)If the substrate metals possesscatalytic activity,the coating rates of electroless plating are mostly equal.

关键词： Electroless pIating substrate metals stationary potential catalytic activity passivity

Effect of substrate micro-morphology on heterogeneous nucleation

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China Foundry 2012年第3期9卷 234-238页

作者： Zhang Ying Wang Meng Lin Xin Huang Weidong State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi'an 710072ShaanxiChina

The heterogeneous nucleation process of NH4Cl crystals from a NH4Cl-70wt.%H2O solution on rough chilling substrates was considered in this paper. Scratched and etched substrates of aluminum were prepared with different surface morphologies. It was concluded that for nucleation to occur on a rough substrate surface, the wettability or the generally said roughness are not the key factors affecting the heterogeneous nucleation process. Rather the surface morphologies on the nanometer scale, which is close to the scale of the critical nucleation radius, are more important.

关键词： grain refinement heterogeneous nucleation substrate micro-morphology

Effect of streambed substrate on macroinvertebrate biodiversity

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Frontiers of Environmental Science & Engineering 2008年第1期2卷 122-128页

作者： Xuehua DUAN Zhaoyin WANG Shimin TIAN Department of Hydraulic Engineering Tsinghua UniversityBeijing 100084China International Research and Training Center on Erosion and Sedimentation Beijing 100044China

Macroinvertebrates areimportantcomponents of stream ecosystems,and are often used as indicator spe-cies for the assessment of river *** studies have shown that substrate is the primary physical envir-onmental variable affecting the taxa richness and density *** aimofthiswork istostudythe effects of the characteristics of streambed substrate,such as grain size,shape,and roughness,on the composition and biodiversity of macroinvertebrates.A field experi-ment was done on the Juma River,a second-order moun-tain stream in northern *** of cobbles,hewn stones,pebbles,coarse sand,and fine sand were used to replace the original gravel and sand bed in a stretch of 30 m in *** sampling results indicated that the macroinvertebrate assemblage is significantly affected by the grain size,porosity and interstitial dimension of the substrate,while it is rarely affected by the shape and the surface roughness of the experimental *** compositions in cobbles and hewn stones were stable and changed least over *** taxa richness and density of individuals in the substrata of cobbles,hewn stones,and pebbles are much higher than in those of the coarse sand and fine sand.

关键词： Macroinvertebrates taxa richness substrate biodiversity

Study of the Interface Between Diamond Film and Si substrate

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Chinese Science Bulletin 1994年第9期39卷 711-714页

作者：詹如娟朱小东汪学毅陈继峰 Department of Modem Physics Structure Research Laboratory University of Science and Technology of China Hefei 230026 PRC

In the recent decade, vapor synthesis of the diamond film has made great ad-vances. The diamond films have been at the initial stage of large-scale application,but the growth mechanism and relationship between the film structure and synthesisconditions have not been fully understood. Though diamond films can be synthesizedon many kinds of substrates, they adhere to substrates very weakly under some condi-tions. Therefore, it is important to investigate the interface state between

关键词： diamond film Si substrate interface adhesion.