Microbial uptake of radiolabeled substrates: estimates of growth rates from time course measurements.

The uptake of [3H]glucose and a mixture of 3H-labeled amino acids was measured, in time course fashion, in planktonic microbial assemblages of the eastern tropical Pacific Ocean. The average generation times of those portions of the assemblages able to utilize these substrates were estimated from a simple exponential growth model. Other workers have independently used this model in its integrated or differential form. A mathematical verification and an experimental demonstration of the equivalence of the two approaches are presented. A study was made of the size distribution of heterotrophic activity, using time course measurements. It was found that the size distribution and the effect of sample filtration before radiolabeling were dependent on time of incubation. In principle, it was possible to ascribe these time dependences to differences in the specific growth rate and initial standing stock of the microbial assemblages.     

固氮蓝藻“红圈病”的研究——Ⅰ.“红圈病”在大面积培养蓝藻中的危害以及防范措施

对蓝藻“红圈病”的病症、发病条件、传播程度方式、危害进行了研究。结果表明,发病条件与蓝藻最佳生长条件基本一致;病原通过水体和带病藻体传播,对藻的产量和质量均造成严重危害。同时探讨了综合防治措施。     

显微高速摄影技术及其在血液微流变学研究中的应用

本文选用金黄地鼠的微血管,利用显微高速摄影技术,放大微观流场和血细胞,连续地“冻结”短瞬间的变化状态,把物理图象呈现在胶片上,经图像分析和数据处理,从定性及定量方面研究血液微流变学,为生命科学和医学研究提供了又一种新的方法。     

基因定点诱变删除及天然α型心钠素的分泌型表达

用基因定点诱变技术,删除了pO_1α ANF表达质粒中的33对碱基,使人α型心钠素结构基因直接与大肠杆菌分泌型表达质粒pIN-Ⅲ-OmPA中的信号肽酶切位点编码区相连,构成天然人α型心钠素的表达质粒pANF,在IPTG诱导下表达28肽的天然人α型心钠素。纯化后的表达产物具有天然心钠素的放免活性和很强的舒张血管的生物活性。     

Description of the neotype ofRepomucenus sagitta (Callionymidae) with comments on the species

The neotype ofRepomucenus sagitta is described. Specimens conspecific with the neotype from India, the Gulf of Thailand, the South China Sea, the Yellow Sea and Australia are described. Sexual characters, geographic variation, habitat and geographic distribution were noted.Repomucenus macdonaldi is a junior synonym ofR. sagitta as defined by the neotype.     

Mathematical modelling of the effect of sole elasticity distribution on pronation.

A coronal plane model of a distributed elastic sole has been proposed and analyzed with respect to the effects of different medial-lateral elasticity distribution on pronation under quasi-static conditions. The distributed model consists of an array of linear vertical line springs. Under minimum energy assumption, the behavior of the top surface of the interface under resultant force and moment loading was shown to be equivalent to that of a rigid-body mechanism under the same loading. The model was then combined with a rigid-link model of the lower limb. Expressions that describe the relationship of the interface aggregate parameters with pronation and the center of pressure were obtained. These expressions were confirmed by an experiment in which the elastic distribution in the interface was systematically varied and the pronation angle and the center of pressure measured. The model has the potential of being a useful analytical tool in the design of elastic soles in running shoes.