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Search Results: 1 - 10 of 43207 matches for " 清水英幸 "
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沙柳沙障的防风固沙效益研究
高永, 邱国玉, 丁国栋, 清水, 虞毅, 胡春元, 刘艳萍, 户部和夫, 王义, 汪季
中国沙漠 , 2004,
Abstract: 研究测定了1m×1m,1m×2m,2m×2m,2m×3m,2m×4m,2m×5m,3m×3m,3m×4m,4m×4m,4m×5m,3m×6m等11种规格沙柳沙障内的风沙活动过程和分布规律。结果说明,不同规格沙障内输沙率随着风速的变化其变化趋势不同,小规格沙障内输沙率与风速呈对数曲线关系,大规格沙障内输沙率与风速之间呈指数曲线关系。沙柳沙障中近地表0~4cm范围内,风沙流中的相对含沙量沙丘下部明显大于沙丘中部和上部,说明沙障导致了近地表风沙流结构发生变化。面积等于或小于1m2的沙障可以完全控制地表风蚀,当沙障面积增加到一定程度后,风蚀深度增加很快。不同规格沙障的防护效益,在大风条件下,小规格沙障的成本效益高于大规格的沙障;在小风情况下,大规格沙障的成本效益大于小规格沙障。
不同碳源及通气条件下lpdA基因敲除对大肠杆菌代谢的影响
李迈,姚善泾,清水
化工学报 , 2006,
Abstract: lpdA基因编码的lipoamidedehydrogenase是丙酮酸脱氢酶复合体、α-酮戊二酸脱氢酶复合体和甘氨酸裂解多酶体系的组成亚基之一.比较了不同碳源及通气条件下,lpdA基因敲除突变E.coli与野生E.coli的发酵特性,并通过对一些主要的酶活和胞内代谢产物浓度的测量,考察了lpdA基因敲除对E.coli代谢的影响.结果表明:葡萄糖为碳源的有氧条件下,lpdA基因的敲除导致丙酮酸、D-乳酸、L-谷氨酸的积累,TCA循环的抑制,乙醛酸途径和磷酸戊糖途径中的磷酸葡萄糖脱氢酶的激活.乙酸或丙酮酸为碳源的有氧发酵及葡萄糖为碳源的微氧发酵实验补充了以上的结论.
溶氧振荡对聚β羟基丁酸混合培养过程的调控作用
钱梓文* 远山正 花强 清水
生物工程学报 , 2001,
Abstract: 研究生物可降解塑料phb(polyβ-hydroxybutyrate)生产的低成本和高产率发酵。采用廉价碳源——废食品糕点作为原料,其中同时具有葡萄糖和乳酸。培养是在同一5l发酵罐中先后接入2种细菌,先由乳酸杆菌lactobacillusdelbrueckii消耗葡萄糖产生乳酸,再由真养产碱菌ralstoniaeutrophus消耗乳酸产生phb。本文应用混沌控制理论设计溶氧振荡来协调混生菌矛盾的生理需求,同时改变振荡节律激励细胞的代谢能。考虑真养产碱菌在乳酸里的代谢,有异养和真养两种途径,其中两种重要代谢通量,生物氧化能atp和还原能nadph,能够反映混生菌细胞的生理状态,二者都与供氧密切有关。实验通过取样进行细胞破碎后,由荧光分析仪监测不同发酵阶段的atp和nadph,发现2种代谢能随着溶氧控制的不同节律变化而起伏,溶氧节律振荡能够使混合培养的phb的浓度比常规供氧方法提高1倍。
一种中间代谢途径代谢通量的定量分析方法
张慧敏?,朱江峰?,清水,姚善泾?
生物化学与生物物理进展 , 2003,
Abstract: 以13c标记的碳源,用二维核磁共振技术(1h-13c,hmqc)测定代谢中产生的氨基酸标记模式,研究对中间代谢途径胞内代谢通量进行定量分析的方法.通过开发软件包,改进同位素分布的数学模型,提出了反应映射矩阵(rmm)等概念.由简化算法,提高程序的执行效率,建立了定量分析胞内代谢通量的平台.代谢模型涉及了糖酵解途径、磷酸戊糖途径、三羧酸循环、几种回补反应、发酵途径和氨基酸合成途径.
在不同碳源培养条件下酿酒酵母的蛋白质组解析
张慧敏 姚善泾* 彭立凤 清水
生物工程学报 , 2004,
Abstract: 为了分析酿酒酵母在不同培养条件下的代谢调控过程的差异,采用固相ph梯度-sds聚丙烯酰胺双向凝胶电泳对其利用不同碳源时细胞的总蛋白进行了分离,银染显色,使用2d蛋白质图像分析系统imagemaster-2delite对双向电泳图谱进行分析,查询swiss-2d-page蛋白质组数据库,识别了约500个蛋白质点。对与糖酵解途径、磷酸戊糖途径、三羧酸循环和几种回补反应相关的大部分关键的蛋白质进行了差异分析。探讨了酿酒酵母利用不同碳源时及生长的不同阶段代谢机理的变化和在蛋白质水平的调控。
近60年来敦煌绿洲耕地动态变化与预测研究
刘普,
土壤 , 2008,
Abstract: 基于敦煌绿洲1949—2004年耕地变化特征、现状及存在问题,选取影响耕地的7个社会经济指标,利用因子分析方法(fa)分析敦煌绿洲耕地变化的驱动力。结果表明农业现代化水平、人口数量和受教育程度是影响绿洲耕地变化的3个主要驱动因子,最后通过gm(1,1)模型对未来25年的耕地和人口进行了预测,以期为敦煌绿洲耕地资源的保护和人地和谐发展提供科学依据。
Dynamic Variance of Intracellular Metabolic Energies Under Rhythmical Control for Dissolved Oxygen in PHB Mixed Cultivation
溶氧振荡对聚β羟基丁酸混合培养过程的调控作用

Z W Qian,M Tohyama,Q Hua,K Shimizu,
钱梓文
,远山正,花强,清水

生物工程学报 , 2001,
Abstract: The mixed cultivation using cheaper carbon source-wasted food material contained glucose and lactate at the same time was conducted in 5L fermentor, within which glucose was converted to lactate by L. delbrueckii in anaerobic condition and the lactate was converted to PHB by R. eutropha in aerobic condition. Considering dissolved oxygen concentration may affect the level of intracellular ATP and NADPH of the metabolic pathways for R. eutropha in lactate under autotrophy or heterotrophy, rhythmical oscillated control for DO based on chaos control method was consequently presented. This method was employed to satisfy two strains for opposite oxygen preferences, moreover, excite the intracellular metabolic energy simultaneously. The values examined through spectrophotofluorimetry represented that both ATP and NADPH exhibited fluctuations in accordance with the DO rhythm. By means of this control design, the concentration of PHB can be doubled than the usual under stable DO control.
Preliminary Proteome Analysis for Saccharomyces cerevisiae under Different Culturing Conditions
在不同碳源培养条件下酿酒酵母的蛋白质组解析

ZHANG Hui-Min YAO Shan-Jing,PENG Li-Feng Kazuyuki Shimizu,
张慧敏
,姚善泾,彭立凤,清水

生物工程学报 , 2004,
Abstract: For the investigation of the metabolic regulation of Saccharomyces cerevisiae under different culture conditions, the proteins of cell utilizing various carbon sources were separated by two-dimensional electrophoresis with immobilized pH gradients as the first dimension and SDS-PAGE as the second. Samples were taken in the log phase of batch culture using glucose or lactic acid as carbon source, while another sample was taken from the broth when glucose was consumed up and ethanol accumulated in the previous phase was further metabolized. After electrophoresis, the protein spots were detected by silver-stain in a Hoefer Automated Gel Stainer with a protein silver staining kit. Silver-stained gels were scanned and digitized to create computer images. About 500 protein spots were detected by employing the 2D proteome image analysis system Image Master 2D Elite and SWISS-2DPAGE proteome database. Most of the protein expressed and involved in the glycolysis, pentose phosphate (PP) pathway, anaplerotic pathway, as well as TCA cycle were analyzed. The metabolism regulation of protein level for Saccharomyces cerevisiae under various carbon sources, as well as during different phase of growth, was studied. The expression of several glycolytic en~zymes(glk, pgi, pgk, eno, pyk) was up-regulated while the expression of enzymes in oxidative pentose phosphate pathway(zwf, gnd) was down-regulated when ethanol and lactic acid were taken as carbon source. Simultaneously, frucotose1,6-biphosphatase was found to be up-regulated due to the gluconeogenic requirement. Citrate synthase and Malate dehydrogenase do not exhibit significant difference, indicating TCA cycle is necessary when utilizing glucose, ethanol or lactic acid as carbon source. Thus, the NADPH loss due to the repressed pentose phosphate pathway could be compensated by TCA cycle in cases of ethanol and lactic acid. The expression of malic enzyme and isocitrate lyase are activated to a large extent when metabolizing ethanol, indicating glyoxylate shunt is essential in transferring ethanol to generate four carbon precursors for the biosynthesis and the NADP-dependent malic enzyme could also serve as compensation mechanism for NADPH loss in this case.
恒电流电沉积ZnO薄膜及其光电性能研究
,程树
福州大学学报(自然科学版) , 2010,
Abstract: 采用恒电流电沉积的方法,在ITO导电玻璃上制备ZnO薄膜.通过X射线衍射仪、扫描电子显微镜等手段,对制备出的ZnO薄膜进行表征,并研究了溶液的pH值对薄膜的光学性质的影响.结果表明,电流密度为0.175mA·cm-2、pH为4.7时,制备出的ZnO薄膜具有纤锌矿结构,薄膜表面较均匀、致密,具有很好的附着力,在可见和近红外波段透过率约为80%,禁带宽度为3.37eV.光电流测试表明薄膜的导电类型为n型.
心室颤时脑微动脉血管的应力实验
王伯初,新见
重庆大学学报 , 1994,
Abstract: 实验测得了猫在心室颤前,后的脑微动脉内径及血压的变化,引入增量应力和应变的概念,计算了在心室颤前后微动脉血管(内径小于100μm)应力与应变的变化规律,并获得了在不同期间内血管的本构方程。
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