Effective extraction of elastase from Bacillus sp. fermentation broth using aqueous two-phase system

INTRODUCTION Aqueous two-phase system (ATPS) is widely used in biochemistry and biotechnology for purifica- tion of proteins (Diamond and Hsu, 1992; Balasubramaniam et al., 2003), enzymes (Pan et al., 2001; Bim and Franco, 2000), amino acids (Li et al., 2002), antibiotics (Yang et al., 1994; Guan et al., 1994), nucleic acids (Ohlsson et al., 1978; Kimura, 2000), aroma compounds (Marco et al., 2000) and lactic acid (Planas et al., 1998). ATPS is mainly composed of two-incompatible p…     

个人意义在外部动机内化过程中的作用探析

外部动机的内化是学校教育情境中激发学生学习动机的一条重要路径。基于自我决定动机理论,可关注外部动机内化的不同类型及意义,认识外部动机内化的实质与机制,揭示个人意义在促进外部动机内化中的作用。为此,教师应给予学生自主支持,引导学生生成具有建设性的理由和进行高水平的内化。     

怎样发挥师专图书馆的教育职能

作者从五个方面分别论述了师专图书馆教育职能的含义、师专图书馆在师生读者中怎样发挥教育职能等问题,同时提出:一定的物质基础和科学的管理手段是师专图书馆教育职能得以充分发挥的有力保障。     

三角形packing问题中零自由度动作的分类

三角形packing问题中三角形可以进行连续平移和旋转,如果不对三角形放置动作进行限制,则计算将无法实现。本文提出了零自由度动作概念,并对它进行了详细的分类,为求解三角形Packing问题建立了一个接近客观情况的模型。     

微孔膜内大分子有效扩散系数的计算

报道一种计算分子尺寸与构型对微孔内大分子有效扩散系数影响的理论方法。基于刚性圆球分子在圆柱型孔内的扩散理论，定义分子平均投影半径和水力学球半径，分别用于估算孔内外浓度分配系数和孔内水力学拖曳力。对不同构型的大分子，使用该法计算的有效扩散系数与已发表的实验数据吻合良好。     

走向校本的素质教育——天津市中小学实施素质教育的研究

一、走向校本———素质教育深化发展的必然从20世纪80年代开始,我国就在不同层面出现了素质教育的实践探索,而且涌现了一批成功的素质教育模式,如“成功教育”、“和谐教育”、“愉快教育”等,并且在不同层面进行了宣传和推介。从1996年起,原国家教委还从区域性层面对实施素质     

Allograftic bone marrow-derived mesenchymal stem cells transplanted into heart infarcted model of rabbit to renovate infarcted heart

Objective: To investigate the directed transplantation of allograftic bone marrow-derived mesenchymal stem cells (MSCs) in myocardial infarcted (MI) model rabbits. Materials and Methods: Rabbits were divided into 3 groups, heart infarcted model with MSCs transplanted treatment (MSCs group, n=12), heart infarcted model with PBS injection (control group, n=20), sham operation with PBS injection (sham group, n=l 7). MSCs labelled by BrdUrd were injected into the MI area of the MSCs group. The same volume of PBS was injected into the MI area of the control group and sham group. The mortality, LVIDd, LVIDs and LVEF Of the two groups were compared 4 weeks later. Tropomyosin inhibitory component (Tn I) and BrdUrd immunohistochemistry identified the engrafted cells 4 weeks after transplantation. Result: The mortality of the MSCs group was 16.7% (2/12), and remarkably lower than the control group's mortality [35% (7/20) (P＜0.05)].Among the animals that survived for 4 weeks, the LVIDd and LVIDs of the MSCs group after operation were 1.17±0.21 cm and 0.74±0.13 cm, and remarkably lower than those of the model group, which were 1.64±0.14 cm and 1.19±0.12 cm (P＜0.05); the LVEF of the MSCs group after operation was 63±6%, and remarkably higher than that of the model group,which was 53±6% (P＜0.05). Among the 10 cases of animals that survived for 4 weeks in the MSCs group, in 8 cases (80%),the transplanted cells survived in the non MI, MI region and its periphery, and even farther away; part of them differentiated into cardiomyocytes; in 7 cases (70%), the transplanted cells participated in the formation of blood vessel tissue in the MI region. Conclusion: Transplanted allograftic MSCs can survive and differentiate into cardiomyocytes, form the blood vessels in the MI region. MSCs transplantation could improve the heart function after MI.     

学习型组织有效性评价

评价学习型组织有效性,应根据学习型组织的定义与特征以及企业的实际情况制定切实可行地评价指标,既要保证评价的客观性,正确性,又要在做法上力求简单,方便操作。学习型组织测评的基本方法是:     

用改进的元胞自动化模型模拟不同信号灯控制策略下的交通流

Traffic flows controlled by traffic light strategies were investigated via a cellular automaton model with anticipation, which is suitable for describing urban traffic. Three kinds of strategies, i. e., synchronized, green-wave and random switching lights, were designed, simulated and compared with each other. It is shown that the green-wave strategy is only valid at lower density and there is not an effective way with the three strategies to improve the efficiency of traffic flow at high density.     

“三个代表”重要思想与党的执政能力建设

学习和贯彻“三个代表”重要思想 ,要以党的执政能力建设为重点 ,全面推进党的建设。党的执政能力包涵“党的领导干部的个体执政能力”和“党的组织的整体执政能力”二个方面。因此 ,加强党的执政能力建设 ,不仅要落脚到党的各级领导干部素质与能力的增强上 ,而且更重要的是要落脚到党组织的领导体制和工作机制的改革上。