UPLC-MS/MS法同时测定桃中氟吡菌酰胺和肟菌酯及其代谢产物

利用超高效液相色谱-串联质谱法（UPLC-MS/MS）,建立桃中氟吡菌酰胺及其主要代谢产物2-（三氟甲基）苯甲酰胺（BZM）和肟菌酯及其主要代谢产物肟菌酸的检测方法。去核粉碎后的桃样品经乙腈提取,C18吸附剂净化,UPLC-MS/MS分析,采用电喷雾正离子（ESI+）模式和多反应监测（MRM）,外标法定量。结果显示,在0.005～0.1 mg/L范围内,4种目标化合物的质量浓度与信号响应的峰面积均线性关系良好,相关系数（r）均大于0.99。在0.01, 0.1, 1, 3 mg/kg的添加水平下,4种目标化合物的平均回收率为77.7%～108.0%,相对标准偏差（RSD）为3.1%～17%。4种目标化合物的定量限（LOQ）均为0.01 mg/kg。该方法符合农药残留分析要求。     

Water in the Neck-Zipper Region of Kinesin

Neck linker （NL） is one of the most important mechanical elements of kinesin motors. The zipping up process of the neck-zipper （NZ） formed by NL and the related secondary structure elements is one of the major parts of kinesin＇s power stroke. All the weak interactions that are responsible for the formation of NZ are sensitive to or dependent on water. To investigate the role of water in the NZ region, a molecular dynamics （MD） model is set up with a crystal structure of kinesin 2KIN surrounded by a 10 A water layer, and minimization is performed to determine the positions of hydrogen atoms and other atoms. It is revealed that water molecules can assist the docking process of NL by forming hydrogen bonds at those positions where direct hydrogen bonding between the two sides of NZ is hindered and then acts as a constructive component of NZ at the docked state of NL. This result may improve the understanding of the mechanism for the docking of NL of kinesin wherein the function of water has not been comprehended sufficiently.     

基于增强现实技术的理论力学新形态教材设计与实践

教材是教育思想、教学内容、教学方法与手段的载体。通过对理论力学教材发展历史及现状的分析,指出了编写与互联网技术相融合的理论力学新形态教材的必要性,分析了以纸质教材为核心、数字课程资源相配套的新形态教材的特点,提出了理论力学新形态教材的设计思路,并介绍了东北大学编写理论力学新形态教材的开发流程和应用效果。