Chemical-Shift Perturbations Reflect Bile Acid Binding to Norovirus Coat Protein: Recognition Comes in Different Flavors

Bile acids have been reported as important cofactors promoting human and murine norovirus (NoV) infections in cell culture. The underlying mechanisms are not resolved. Through the use of chemical shift perturbation (CSP) NMR experiments, we identified a low-affinity bile acid binding site of a human GII.4 NoV strain. Long-timescale MD simulations reveal the formation of a ligand-accessible binding pocket of flexible shape, allowing the formation of stable viral coat protein–bile acid complexes in agreement with experimental CSP data. CSP NMR experiments also show that this mode of bile acid binding has a minor influence on the binding of histo-blood group antigens and vice versa. STD NMR experiments probing the binding of bile acids to virus-like particles of seven different strains suggest that low-affinity bile acid binding is a common feature of human NoV and should therefore be important for understanding the role of bile acids as cofactors in NoV infection.     

MC6845在工业控制机中的应用

MC68 4 5是Motorola生产的一种 4 0引脚的双列直插式可编程器件 ,阐述了一种用MC684 5制作的工业控制机图形显示模板的电路原理 ,其设计思路对从事这方面的开发和应用都会有所启发。     

基于STD工控机的浓密自动控制系统

根据浓密工艺特点 ,采用STD工控机和模糊控制技术开发了浓密自动控制系统。该系统在红布金矿成功应用 ,具有性价比高 ,稳定可靠的特点。本文对控制任务 ,控制方案 ,系统特点 ,系统设计进行了介绍     

基于STD标准的信号模型研究

针对测试信号种类繁多,属性复杂的问题,充分发挥了STD（Signal and Test Definition）标准的扩展机制,分别研究了基于STD标准的静态信号模型和动态信号模型。并应用上述模型,建立了带有电流限属性的三相交流电信号模型,解决了三相交流电信号的使用问题,同时为自定义信号的建模提供思路。     

STD‐NMR‐Based Protein Engineering of the Unique Arylpropionate‐Racemase AMDase G74C

Structure‐guided protein engineering achieved a variant of the unique racemase AMDase G74C, with 40‐fold increased activity in the racemisation of several arylaliphatic carboxylic acids. Substrate binding during catalysis was investigated by saturation‐transfer‐difference NMR (STD‐NMR) spectroscopy. All atoms of the substrate showed interactions with the enzyme. STD‐NMR measurements revealed distinct nuclear Overhauser effects in experiments with and without molecular conversion. The spectroscopic analysis led to the identification of several amino acid residues whose substitutions increased the activity of G74C. Single amino acid exchanges increased the activity moderately; structure‐guided saturation mutagenesis yielded a quadruple mutant with a 40 times higher reaction rate. This study presents STD‐NMR as versatile tool for the analysis of enzyme–substrate interactions in catalytically competent systems and for the guidance of protein engineering.     

电视发射机自动监控系统

本文介绍了一种电视发射机自动监测控制系统。该系统针对由一部10kW主发射机和一部1kW备用发射机组成的电视节目信号发射系统，采用PC机、STD工控机与“虎翼组态软件”构成一个主从机系统，对电视发射机进行自动控制和管理。     

面向信号的仪器功能描述方法研究

针对测试仪器的功能描述问题,参照STD标准建立的信号模型,通过定义仪器可以产生和测量的信号,实现了对仪器测试/激励能力的描述.通过定义逻辑资源,并且把仪器的测试/激励信号能力映射到仪器可实现的逻辑资源之上,描述了仪器产生或测量信号之间的约束或依赖等复杂关系.     

YKA7232型数控蜗杆砂轮磨齿机控制系统设计

ＹＫＡ７２３２型数控蜗杆砂轮磨齿机采用１６位ＳＴＤ总线工业控制机和光栅和光电编码器元件，可进行６轴控制４轴联动的全交流伺服闭环控制。文章介绍了机床系统硬件和软件的构成，特点及功能。     

大型电机温度参数在线监测系统

叙述了大规模电机温度监测系统的构成方法,并提出了在强电磁干扰环境下的稳定运行的措施。     

空气压缩机站微机监控系统

介绍一个由ＳＴＤ微机组成的空气压缩机站得机监控系统的功能及其构成、系统软件编制、抗干扰措施等。该监控系统巳用于一空压站对７台空气压缩机的７８路压力、温度、差压、流量等模拟信号、冷却水流量下限开关信号（７路）实施监控，并对５台干燥器实现程序控制。该系统已投入运行，达到预期要求。