An integrated downstream processing strategy for the recovery and partial purification of penicillin acylase from crude media

An integrated process strategy for the recovery of penicillin acylase was developed, based on precipitation of non‐enzymatic proteins directly from Escherichia coli homogenates or crude extracts using Rolquat (quaternary ammonium salt) and adsorption of the enzyme on Amp‐Seph (3.8 µmole ampicillin cm^?3) under pseudo‐affinity conditions. The effect of pH, concentrations of ammonium sulfate and Rolquat, and also concentrations of protein and cell debris on the precipitation of non‐enzymatic proteins from homogenates and crude extracts of penicillin acylase were analysed. The method of addition of Rolquat to homogenates and crude extracts significantly influenced the size of the precipitated particles. Improved results on the specific activity of penicillin acylase were obtained for 22% and 1% (w/v) of ammonium sulfate and Rolquat, respectively, added sequentially to enzyme solutions and at room temperature. Under these experimental conditions, the specific activity of penicillin acylase in homogenates and crude extracts was enhanced 2.5–3.0‐fold. Finally, the integrated process strategy was implemented first by precipitation of non‐enzymatic proteins and recovery of penicillin acylase directly from the enzyme solution treated with Rolquat using an adsorption/filtration system with an overall yield of 86%. This system allows simultaneously the filtration of cell debris and fine precipitated particles, in situ recovery of penicillin acylase by its adsorption on Amp‐Seph, and selective desorption of the enzyme with a specific activity of 11 IU (mg prot)^?1 and a desorption yield of 95%. © 2002 Society of Chemical Industry     

适用于仿真工业控制系统的软件包

本文提出的仿真软件包具有丰富的数学运算功能、控制算法功能、逻辑运算功能及图形编辑能力．软件包结构上充分体现了模块化的设计思想，而在功能及组态方法上又十分类似于分散控制系统相应的功能。使用该软件包，可方便地对各种典型的工业控制系统特别是由微处理机组成的分散控制系统进行仿真研究。     

NCFW专家系统的汉语接口

NCFW系统是适合于花岗岩与变质岩地区的勘探地下水专家系统，系统的人机交互既可用菜单（亦称项目单）方式，亦可用汉语对话方式。这两种方式既可混合使用亦能灵活切换。本文着重描述了汉语接口的设计思想、实现中采用关键技术以及系统运行实例。     

异步电机性能微机测试系统设计

结合工程实际介绍了异步电机计算机辅助测试（CAT）系统的硬件、软件组成、技术方案确定以及设计原则。现场运行表明，该系统稳定可靠，且具有较高的性能价格比。     

国内模板体系发展趋势分析

分析了形成国内模板体系现状的潜在基本原因,并提出了国内模板体系未来发展的方向。     

微机控制缠绕机控制系统的数字仿真监测

本文采用控制系统的数字仿真技术，在ＳＴＤ工业控制机上实现了对微机控制纤维缠绕机控制系统的稳速精度、跟踪性能和光电编码器的性能的监测。文中阐述了检测电路、测量方案、仿真程序设计和结果分析等内容。     

从CCIR的活动看广播电视技术的发展

本文描述在CCIR活动中对HDTV统一标准的争论和趋势。有关ETV,D2-MAC及数字电视地面广播系统的CCIR建议书,以及美国全数字HDTV的发展也作了介绍。     

Does the Youth Corrections System Work? Tracking the Effectiveness of Intervention Efforts With Delinquent Boys in State Custody.

This study adopted a systemic approach to studying intervention efforts with delinquent youth, examining the association between several youth corrections programs and adult criminal outcomes. Two studies were designed to use juvenile and adult court records to evaluate the effectiveness of treatment programs provided to delinquent youth in state custody. The results of Study 1 suggested that court-recorded delinquent charges can be used to estimate delinquency severity. The results of Study 2 presented a discouraging but not entirely unexpected illustration of the effectiveness of intervention efforts among delinquent youth. It was found that time spent in juvenile detention facilities, work programs, and group homes was associated with negative adult criminal outcomes. No links between time spent in youth corrections programs and positive outcomes were identified. Implications for future program evaluation efforts are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)