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Search Results: 1 - 10 of 52930 matches for " 马诗淳 "
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xyl-d二型乙醇脱氢酶(SADH)G198R?ね槐涮宓难芯?
The study onxyl-d second alcohol dehydrogenase (SADH) G198R mutant

韩俊,刘志斌,,杨毅
- , 2015,
Abstract: 本研究通过设计简并引物及文献参考, PCR克隆得到嗜热厌氧菌菌株xyl d的??SADH??, 并利用定点诱变技术将该酶的198位苷氨酸(Gly)突变为精氨酸(Arg). 将野生型和突变基因连接到原核表达载体pET28a, IPTG诱导表达, 再经镍柱纯化, 然后比较了两个蛋白分别以NAD/NADH, NADP/NADPH为辅因子、异丙醇或异丁醛为底物、55 ℃条件下的酶活. 发现突变后蛋白的总体催化活性相对于野生型有所下降, 其中突变蛋白对NAD/NADH的亲和性分别下降了约8倍和6倍, 而且对NADPH的亲和性下降也非常明显, 但对NADP的亲和性变化却不大.
The SADH of xyl d had been cloned by designing degenerate primer , and alerted Gly????198?? to Arg by PCR site directed mutagenesis techniques .The gene of the wild type and the mutant were linked to the prokaryotic expression carrier pET28a, then induced by IPTG and purified out by Nickel column. The catalytic activity of the two proteins were detected and compared when NAD / NADH, NADP / NADPH as coenzyme factors, isopropanol or isobutyraldehyde as substrate and the temperature was 55 ℃. It was found that the overall catalytic activity of the mutant enzyme was decreased. And the mutant protein affinity for NAD / NADH were respectively decreased to about 8 fold and 6 fold. The affinity for NADPH also decreased obviously. But The affinity for NADP changed a little
一株兼性嗜冷产甲烷杆菌的分离与系统发育学分析
杨丽丽,杨磊,,邓宇,张辉
应用与环境生物学报 , 2011, DOI: 10.3724/SP.J.1145.2011.00256
Abstract: 从云南哀牢山泥土中分离出一株生长温度范围为7~40℃的兼性嗜冷产甲烷杆菌8-1.该菌株革兰氏染色阳性,直径0.2~0.3μm,长2~5μm,具有弯曲和微弯杆状两种形态,不运动,单生?成对?多数成聚集状态存在.能够利用h2/co2和甲酸盐生长,不利用甲醇?三甲胺?乙酸和二元醇类.最适生长条件:温度为35℃,ph值为7.5~8.5,盐浓度为0mol/lnaci.最低生长的温度可达到7℃.菌株8-1与标准株methanobacteriumsubterraneumstraina8p(=dsm11074t)的16srrna基因序列相似性为99%.图5表1参17
Characterization of an acidotolerant, thermophilic Thermoanaerobacter sp. xyl-d with a high xylose conversion
一株高效降解木糖的耐酸、嗜热厌氧杆菌的生理特性及产物分析

Wenjing Zhang,Shichun M,Yu Deng,Hui Zhang,
张文静
,,邓宇,张辉

微生物学报 , 2011,
Abstract: Objective] We screened a thermophilic xylolytic bacterium that produced fuel ethanol from a high-temperature oil reservoir,and provided microbial resources to genetic engineering strains construction and consolidated bioprocessing.Methods] We adopted Hungate anaerobic technique to isolate strain xyl-d from oil reservoir water sample enriched for two years from Shengli Oilfield in China,and we identified strain xyl-d with morphological,physiological,biochemical and phylogenetic analysis.Results] Strain xy...
Isolation, identification and enzyme characterization of a thermophilic cellulolytic anaerobic bacterium
嗜热厌氧纤维素分解菌的分离、鉴定及其酶学特性

Yinping Zhao,Shichun M,Yingjie Sun,Yan Huang,Yu Deng,
赵银瓶
,,孙颖杰,黄艳,邓宇

微生物学报 , 2012,
Abstract: Objective] To identify a thermophilic bacterium from horse manure to degrade cellulose efficiently,and to enrich microbial resources producing cellulolytic ethanol by co-culturing with thermophilic ethanol producing bacterium.Methods] We used Hungate anaerobic technique to isolate a strain named as HCp from horse manure mixed culture;its phylogeny was identified through 16S rDNA sequencing.Enzymatic assays were determined using DNS method.Results] The isolated HCp cells were straight with rods size of(0.35-0.50)μm ×(2.42-6.40)μm,in the form of single or paring.This strain belongs to a strictly anaerobic Gram-negative bacterium,it is able to form spores,shows motile ability and resistance to neomycin.The strain could degrade filter paper cellulose,cellulose powder,microcrystalline cellulose,cotton wool,rice straw and gelatin,and it was also able to utilize abundant saccharides as substrates such as cellobiose,glucose,xylose,xylan,raffinose,maltose,sorbose,fructose and galactose.The growth pH ranges from 6.5 to 8.5,temperature from 35 to 70℃ and concentration of NaCl on cellulose from 0% to 1.0%,while the optima of pH6.85,60℃ and 0.2% NaCl.Under the optimal growth conditions,the filter paper cellulose degradation rate was up to 90.40% after 10 days.The optimum temperatures for FPA,CMCase,β-glucosidase and xylanase were 70℃,70℃,70℃,and 60℃ respectively.CMCase activity was found with high thermal stability.The phylogenetic analysis based on partial 16S rDNA revealed that HCp was close to Acetivibrio cellulolyticus and A.cellulosolvens with 97.5% sequence similarities.Conclusion] Strain HCp is thermophilic,efficiently cellulolytic anaerobe.It is able to utilize vast substrates and produce highly thermostable enzymes.It is a potential bacterium that can be used for cellulolytic ethanol production.
Progress in Microorganisms Producing Hydrogen by Anaerobic Metabolism
厌氧产氢微生物研究进展

MA Shi-Chun,LUO Hui,YIN Xiao-Bo,ZHANG Hui,DENG Yu,
,罗 辉,尹小波,张 辉,邓 宇

微生物学通报 , 2009,
Abstract: Microorganisms play a key role in bio-hydrogen producing. Progress in microorganisms producing hydrogen by anaerobic metabolism is reviewed in recent years in the present paper. The species of microorganisms producing hydrogen by anaerobic metabolism, and current status of breeding and application of efficient hydrogen-producing microorganisms were summarized. The hydrogen-production capability, substrates utilization, and metabolic characteristics of anaerobic and thermophilic hydrogen-producing microorganisms were summarized especially, the species and metabolic characteristics of thermophilic carboxydotrophic hydrogenogenic bacterium were introduced briefly.
2型糖尿病对腰椎间盘突出症影响的回顾性分析
孙浩林,,
北京大学学报(医学版) , 2011,
Abstract: ?目的:研究2型糖尿病对腰椎间盘突出症的发病率和严重程度的影响。方法:回顾性研究1999年10月至2008年10月间北京大学第一医院骨科手术治疗腰椎间盘突出症的病例575例(年龄40~70岁),确定合并2型糖尿病病例的数量和比例;选择同期、同年龄段手术治疗拇外翻、腕管综合征、肘管综合征和腱鞘囊肿病例219例作为对照组,确定合并2型糖尿病病例的数量和比例;应用χ2检验比较腰椎间盘突出症组和对照组合并2型糖尿病比例。将腰椎间盘突出症组分为合并2型糖尿病组和不合并2型糖尿病组两个亚组,观察两亚组病例腰椎间盘手术节段、腰椎间盘突出类型(包含型与非包含型)、术后是否复发行二次手术;应用独立样本t检验比较两亚组间腰椎间盘手术节段数量;应用χ2检验比较两亚组间腰椎间盘突出包含型和非包含型所占比例、术后复发行二次手术比例。结果:腰椎间盘突出症组的合并2型糖尿病的比例为15.3%(88/575),显著高于对照组7.76%(17/219,χ2=7.861,p=0.005),也高于北京地区40~70岁人群2型糖尿病发病率9.94%(188/1892,χ2=12.788,p=0.0004)。腰椎间盘突出症组亚组间比较结果为平均手术节段:合并2型糖尿病亚组1.19、不合并2型糖尿病亚组为1.15(t=0.703,p=0.483);腰椎间盘突出类型及比例:合并2型糖尿病亚组为包含型65.7%(58/88),非包含型34.3%(30/88),不合并2型糖尿病亚组为包含型70.5%(343/487),非包含型29.5%(144/487)(χ2=0.722,p=0.395);术后复发比例:合并2型糖尿病亚组为3.41%(3/88),不合并2型糖尿病亚组为3.89%(19/487,χ2=0.034,p=0.854)。结论:在手术治疗腰椎间盘突出症的中老年患者中,相比同龄行其他择期手术的患者合并2型糖尿病的比例增高,2型糖尿病可能增加腰椎间盘突出症的患病风险。
二语词汇阅读的跨语言语音干扰:语义关联判断任务的证据
,
心理学报 , 2015,
Abstract: ?研究采用语义关联判断任务探讨二语词汇阅读的跨语言语音干扰现象。共有35名英语专业硕士研究生参加了实验,平均年龄23.17岁;同时为提供比对的基准样本,还挑选了35名英语本族语者参加实验,平均年龄26.06岁。语义关联判断任务实验结果表明,中国英语学习者,在对同音词对进行语义关联判断时,不仅在错误率上要比控制条件显著更高,而且在作出判断时的速度也要显著更慢。这种语音干扰效应的出现为二语词汇阅读时语音信息的自动激活提供了有力的证据。这也说明,在本研究中词汇入口由同音词经过语音路线而通达。另外,结果还表明,中国英语学习者在对由英语元音对比音/i/-/i/组成的词汇最小对立体进行语义判断时,不仅在错误率上要比控制条件显著更高,而且在作出判断时的速度也要显著更慢;但是英语本族语者不管是在错误率还是在反应时,实验条件下与控制条件下都没有区别。这一结果证实了中国学习者在进行二语词汇阅读时跨语言语音干扰的发生,说明二语词汇的心理表征受母语语音系统的影响。
基于相关性分析的结构可靠性加严试验方法
Hardened test method of structural reliability based on correlation analysis

小兵,章健,赵宇
- , 2017, DOI: 10.13700/j.bh.1001-5965.2016.0420
Abstract: 摘要 针对传统结构可靠性试验的验证多是基于载荷应力和结构强度相互独立的假设问题,从应力和强度数据的相关性分析与度量出发,在二者均为正态随机变量的前提下,建立了一种基于Copula函数相关应力-强度干涉模型的结构可靠性加严试验验证方案设计方法。该方法结合Copula函数和应力-强度干涉模型实现相关条件下原可靠性指标与加严条件下可靠性指标的转化,适用于小样本情况下基于传统成败型试验方法评估其可靠性。研究结果表明:相比独立假设,应力和强度呈负相关时,会增加试验样本量且样本量随负相关程度减弱而减少;呈正相关时,会减少试验样本量且样本量随正相关程度增强而减少。
Abstract:The traditional test verification of structural reliability is generally based on the independence assumption between loading stress and structural strength. Stating with the correlation analysis of stress and strength, we propose a hardened test method of structural reliability verification based on the stress-strength interference model with Copula correlation when loading and strength both follow the normal distribution. The method combines Copula functions with stress-strength interference model to achieve the transformation of the original reliability index and reliability index under the hardened condition, and the reliability is estimated by the traditional binomial distribution test under the condition of small sample. Compared with the independence assumption, the results show that the negative correlation between stress and strength leads to the increase of sample size and the sample size decreases with the decrease of negative correlation; the positive correlation leads to the decrease of sample size and the sample size decreases with the increase of positive correlation.
河南某污灌区土壤-作物-人发系统重金属迁移与积累
建华,,陈云增
环境科学学报 , 2014,
Abstract: 开展污灌区土壤-作物-人发系统(SCHS)重金属迁移与积累研究,对于维护农田生态系统和人体健康具有重要意义.以河南某污灌区为例,采集土壤和小麦籽粒样品各27份、人发样品355份,用原子吸收法测定Cu、Zn、Pb、Cd含量,用二乙基二硫代氨基甲酸银分光光度法测定As含量,开展重金属在SCHS中的迁移与积累探讨.结果表明,污灌区土壤和小麦籽粒发生了不同程度的重金属污染.土壤Cu、Zn、Pb、Cd和As平均含量分别为40.63、203.47、22.10、1.84、26.87mg·kg-1,小麦籽粒中上述重金属平均含量分别为10.10、25.83、0.87、0.56、0.35mg·kg-1,都高于对照区.污灌区人发中上述重金属平均含量分别为14.11、143.13、13.24、0.19、1.97mg·kg-1,高于对照区,人发多数重金属含量随年龄增长呈增加趋势,男性高于女性.污灌区人发对小麦籽粒重金属的富集系数(BAF人发/小麦)远大于小麦籽粒对土壤重金属的富集系数(BAF小麦/土壤),人发对大多数重金属的放大作用显著.在SCHS中,大多数重金属沿土壤→小麦籽粒→人发的迁移与积累曲线呈不规则"V"形,长期污灌样点的土壤和小麦籽粒重金属污染程度、人发重金属含量都高于"清污"混灌的样点.
对平装期刊牛皮纸全封皮工序的改进
邹常,爱芳
中国科技期刊研究 , 2001,
Abstract: 传统的期刊平装方法,经过若干工序将多册期刊合订为一体后,最后两道工序就是用牛皮纸裱糊全封皮;并在封皮、书脊上书写刊名、年限和起至期号。在多年的工作实践中,我们对期刊平装方法的这两道工序进行了改进,收到了良好的效果。
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