处理甲苯废气的生物滴滤池中微生物生态学研究

利用PCR-DGGE技术分析了处理甲苯废气的生物滴滤池生物多样性,结果表明：在运行过程中,随着生物滴滤池对甲苯去除能力的不断增加,填料当中的微生物种群也发生了明显的变化。在甲苯的选择压力下,随时间的迁延,微生物种类减少,优势种群的相对丰度增加,处于不同层面填料上的微生物分布也趋向于一致。     

Response acquisition with delayed reinforcement in Lewis and Fischer 344 rats

Previous work has shown neurochemical and behavioral differences between Lewis rats and Fischer 344 rats. Some of this work suggests that there might be differential sensitivity to delayed reinforcement between the two strains. To further explore this possibility, Lewis (n=8) and Fischer 344 (n=8) rats were exposed to a response-acquisition task with a non-resetting 20s delay to reinforcement. A tandem fixed-ratio 1, fixed-time 20s schedule of reinforcement was programmed for one of two levers; presses on the alternate lever had no programmed consequences. A greater number of Lewis rats (5/8) acquired lever pressing compared to the Fischer 344 rats (2/8). Future work with these strains may lead to a better understanding of the genetic and/or neurochemical factors involved in temporal control of behavior.     

杨梅基因组DNA提取方法筛选和优化研究

选择具有代表性的杨梅品种20份,分别采用CTAB法和SDS法,选取嫩叶进行基因组DNA提取比较研究,结果表明,由于叶片中含有较高的酚类物质,相对来说CTAB法优于SDS法,提取的基因组DNA色泽白亮且数量多,而且同一提取方法如CTAB法,不同品种之间提取得率也有较大差异。在CTAB法的基础上,选取两个品种研究水浴时间对DNA提取的影响,发现DNA得率随水浴时间的延长呈现抛物线态势,最佳水浴时间随样品颗粒的大小而变化,一般最佳时间为30～40min,样品颗粒较细时水浴时间以30min为最佳,较粗时则为40min。添加异丙醇量以2/3为好,析出DNA的最佳离心速度和时间分别为5 000r/min和10～15min。     

Software sensors for the monitoring of perfusion cultures: Evaluation of the hybridoma density and the medium composition from glucose concentration measurements

New software sensors based on the Extended Kalman Filter technique have been developed for the monitoring of animal cell perfusion cultures. They use a kinetic model describing the growth, death and metabolism of hybridoma cells as a function of the medium composition. The model was initially validated on a batch culture and found to correctly predict the continuous perfusion culture kinetics, except for the production of ammonia and lactate. Using the measurement of a single component in the culture medium, in this case glucose, the Extended Kalman Filter provides an excellent evaluation of the time variation of the concentrations of living and dead cells, of glutamine and antibodies, during the whole perfusion culture for a retained cell density rising from 1 to 11×10⁶ cells.ml^–1 inside the reactor.     

处理甲苯废气的生物滴滤池中微生物生态学研究

利用PCR-DGGE技术分析了处理甲苯废气的生物滴滤池生物多样性,结果表明:在运行过程中,随着生物滴滤池对甲苯去除能力的不断增加,填料当中的微生物种群也发生了明显的变化。在甲苯的选择压力下,随时间的迁延,微生物种类减少,优势种群的相对丰度增加,处于不同层面填料上的微生物分布也趋向于一致。     

Competition between two stream dwelling filter-feeders,Hydropsyche oslari and Simulium virgatum

Summary This study investigated whether interspecific competition affected the abundance and distribution of Hydropsyche oslari and Simulium virgatum. In addition, I studied the mechanisms of competition between the two taxa. H. oslari was the superior competitor when compared to S. virgatum because the presence of H. oslari in boulder habitats in Refugio Creek altered the microdistribution and depressed numbers of S. virgatum. Hydropsyche preempted space and was aggressive towards Simulium. Simulium avoided both hydropsychid larvae and their nets. This avoidance behaviour was reinforced by aggression from H. oslari. Possible immediate reasons why simuliids avoided Hydropsyche nets included 1) Hydropsyche attacked Simulium, 2) occupied nets interfered with feeding through increased turbulence or lower renewal rate for food, and 3) Simulium preferred to settle with conspecifics.     

等压微孔过滤法测定红细胞变形性的理论模型

等压微孔过滤法是测定红细胞变形性的重要手段。以往关于红细胞悬浮液等压微孔过滤的理论模型 ,没有考虑对过滤有显著影响并蕴含重要信息的滤膜堵塞现象 ,而且都存在一些问题。在考虑滤膜堵塞的前提下 ,建立了新的理论模型 ,能够从等压微孔过滤的实验结果方便地算出红细胞平均过孔时间τ和堵孔红细胞比例ε两个直观的变形性参数。分析了以往模型中的不当之处并加以纠正 ,得出了与新模型一致的结果。     

微孔过滤法测定红细胞变形性的统一理论模型

在红细胞悬浮液过滤前后压积不变的合理假设下,并考虑到微孔滤膜堵塞现象,建立了微孔过滤法测定红细胞变形性的统一理论模型－流导模型。该模型利用滤膜相对流导Ｃ与悬浮液滤过体积Ｖ之间的线性关系表达实验结果。利用这一模型,从微孔过滤实验得到了分别反映平均变形性和堵塞信息的两个微观参数;红细胞平均相对过孔阻力β和导致滤膜堵塞的红细胞比例ε。流导模型对各种不同的过滤方法给予统一的描述,对现有的过滤方法或可能出现