改进的锐孔法制备粒径均一的聚乳酸微球

锐孔法是制备微胶囊的常用方法之一。文中根据微通道法乳化技术原理,改进了锐孔法实验装置并用于聚乳酸微球的制备;应用简化的聚乳酸微球制备模型,研究了油相注入速率、搅拌器转速、聚乳酸浓度和锐孔内径大小等因素对聚乳酸微球平均粒径d和粒径分布系数(C V)的影响。结果表明,油相注入速率小于1.2 mL/min时,对d和C V影响较小;提高搅拌器转速能降低d;随着聚乳酸浓度的增大,d和C V均呈增大趋势;当锐孔内径处于200μm~550μm时,d和C V与锐孔内径无明显关系。用内径50μm玻璃毛细管针头代替金属针头,成功地制备出粒径均一的聚乳酸微球(d=77.93μm,C V=17.59%)。     

块状凝胶的制备及其协助溶菌酶复性的研究

利用水溶液聚合法合成温敏型聚N-异丙基丙烯酰胺(PNIPA)块状凝胶,对其性能进行了表征并将其应用到溶菌酶的复性研究中.制得的PNIPA凝胶的低临界溶解温度为33℃,最大溶胀倍率为27,凝胶达到溶胀及缩水平衡需24h.加入270 mg/mL凝胶时,溶菌酶复性后的比活力达到5 450.6 U/mg,与稀释复性相比提高了61.5%.对复性机理的分析表明:聚合物长链上的疏水基团与折叠中间体间的疏水相互作用是PNIPA凝胶协助复性的关键.     

浅谈学生体育锻炼主观能动性的培养

针对当前普通高职院校学生在体育锻炼中,主动性严重不足的现状,对培养学生良好的学习动,充分发挥学生自身的主观能力性提出若干对策。     

一种溶解酶(ATE)的分离纯化及其稳定性

An antithrombus enzyme (ATE) was precipitated by (NH4)2SO4 or ethanol from supernatant of Bacillus subtilis culture broth then purified using ion exchange chromatography on CM-sepharose fast flow. The effects of ionic strength and pH value on protein adsorption, the gradient elution at different flow rates and step elution were examined respectively. The recovery yield of the optimised process was 74.5% with a purification factor 8.1. The ATE molecular weight was estimated as 30ku by SDS-PAGE. The experimental results showed that the enzyme was stable in the range of pH 7 to pH11, and temperature 25℃ to 37℃.     

凝胶层析法纯化纤维素酶的研究

The gel filtration was carried out for purification of cellulase.The influences of chromatographic parameters on the resolution were studied to determine the optimal conditions for purification.The purified endoglucanase was obtained by gel filtration by Superdex 75 prep grade with an activity recovery of 92.8% and the purification factor 4.2.The sample volume should be below 6% of the column bed volume and the column bed height L≥12.0 cm.The optimum catalysis temperature and pH for the enzyme were 55℃and 4.5-.0 respectively.The cellulase was stable at pH ranging from 4.0 to 6.0 and temperature below 60℃.     

6α-甲基可的松C1,2微生物脱氢反应的研究

利用简单节杆菌对6α-甲基可的松C1,2位脱氢,考察了脱氢反应温度、pH值以及底物的投料浓度和方式对底物转化率的影响,得到了较好的反应条件为脱氢反应温度33℃,pH值7.0~7.2,拟结晶投料方式增加底物的投料浓度。在3.7 L发酵罐中进行脱氢反应初步放大试验,得到了菌体生长及底物转化率曲线。利用遗传算法对培养基组成进行了优化,在摇瓶培养中当投料浓度为1.0%时,底物的转化率提高到94.51%。     

人γ-干扰素基因工程菌培养条件的研究

对表达重组人γ-干扰素的基因工程菌的培养条件进行了较详细的研究．确定了最佳的培养及诱导时间，并利用正交试验设计，对影响工程菌生长和重组人γ-干扰素表达的条件如培养基中葡萄糖、蛋白胨、酵母提取物的量及摇床转速、装液量、接种量、pH等进行了优化．结果表明，在优化条件下，表达的γ-干扰素包涵体占菌体总蛋白的60％以上，每升发酵液可获得包涵体约为1．6g．     

Sorption and Diffusion Behavior of Carbon Dioxide into Poly（l-lactic acid） Films at Elevated Pressures

Equilibrium sorption amount, desorption diffusion coefficients and sorption diffusion coefficients of CO2 in poly（l-lactic acid） （PLLA） films at elevated pressures were determined by the gravimetric method, in which the Fick＇s diffusion model was applied to analyze both the desorption and sorption processes. The equilibrium sorption amount of CO2 in PLLA increased with lowering temperature and elevating pressure at the temperature range from 40 to 60 ℃ and pressure from 10^4 to 2x10^4 kPa. Desorption diffusion coefficients were greatly influenced by the equilibrium sorption amount, and they were in the same order of magnitude as the sorption diffusion coefficients. The scan electron microscope （SEM） photos demonstrated that there was no foaming phenomenon of the PLLA film during desorption and sorption processes. The XRD spectra implied that the crystalline degree of PLLA film decreased after CO2 processing. It was concluded that PLLA polymer could be well swollen and plasticized by supercritical CO2.     

超临界抗溶剂沉淀蛋白质的研究(一)——加压CO2对纤维素酶酶活的影响因素

测定了10wt%～40wt%乙醇-水溶液中的纤维素酶,在温度为20℃-40℃和CO2压力为049MPa-4.41MPa下的酶活变化数据,这些数据对于用高压CO2分离纯化纤维素酶具有指导意义.实验表明,CO2压力不是酶活损失的主要因素,乙醇浓度和温度对酶活损失的影响较大.在乙醇浓度小于30wt%,温度低于35℃的条件下,对纤维素酶-乙醇-水体系进行高压CO2处理比较适宜.     

水力空化混合强化超临界流体辅助雾化制备罗红霉素超细微粒

分析了超临界流体辅助雾化（SAA）过程,发现饱和器内超临界二氧化碳与溶液的混合是SAA成功的关键因素之一,由此引入了水力空化混合器以强化饱和器内两相间的传质。在自行组建的引入水力空化混合器的超临界流体辅助雾化（SAA-HCM）装置上,以罗红霉素为模型药物,考察了混合器压力、沉淀器温度、溶剂、进料中CO₂与液体溶液流量比（R）和溶液浓度对微粒形态和粒径的影响。结果表明,水力空化混合器能有效地强化两相间的传质,SAA-HCM工艺可制备出罗红霉素超细微粒,大部分微粒形态呈球形,通过改变操作参数可制得粒径在1～3 μm的适于吸入式给药的气溶胶药物微粒和粒径小于1 μm的超细微粒。