Caged Thiophosphotyrosine Peptides

No Abstract     

One-step hydrolysis for the preparation of carboxylated cellulose nanofibrils with highly stable dispersibility from pomelo peel

Cellulose - One-step acid hydrolysis was successfully employed to prepare carboxylated cellulose nanofibrils (CCNFs) from pomelo peel waste with the mixture of hydrochloric acid and citric acid...     

化学教学中的素质教育

长期以来,人们习惯于把化学教育单纯地看成学科专业化教育,而"仅用专业知识教育人是不够的,通过专业教育,他可以成为一种有用的机器,但并不能成为一个和谐发展的人"(爱因斯坦语),这就要求化学教师在传授化学基础知识、基本技能的同时,充分利用化学知识的文化价值、社会价值和教育价值,积极探索化学教育实现素质教育的方法和途径,使得学生学会做人、学会学习、学会生活、学会劳动、学会健体、学会审美和学会创造.     

气相色谱-单光子电离飞行时间质谱的联用及在柴油组分表征中的应用

建立了一种气相色谱(GC)与单光子电离-飞行时间质谱(SPI-TOF MS)联用(GC/SPI-TOF MS)的分析方法。首先,设计了一种双层套管的传输管用于连接GC与SPI-TOF MS,实现了GC与单光子电离离子源的无缝连接。在此基础上,以n-十五烷标准品和苯/甲苯/二甲苯的标准气为对象,对电离源的重要电压参数进行了优化,得到了纯净的分子离子峰,实现了对各类有机物的快速和准确定性。最后,将该方法用于分析柴油中的挥发性与半挥发性有机物,获得了柴油组分的二维GC×SPI-TOF MS谱图。不需要复杂的谱图解析和数据处理,根据谱图中离子的质荷比(m/z)归纳了柴油的主要成分,包括脂肪烃、芳香烃和含量很低的苯并吡咯等含氮化合物;根据色谱的保留时间将柴油中的同分异构体区分开来。结果表明GC/SPI-TOF MS法是一种简单、有效的分析方法,非常适于柴油及复杂环境样品等的分析表征。     

LIBS技术在土壤重金属污染快速测量中的应用

激光诱导击穿光谱(laser-induced breakdown spectroscopy,LIBS)作为一种很有前景的分析和测量技术在过去的10多年中已经显现出来.本文介绍了激光诱导击穿光谱的工作原理和定量定性分析的理论基础,综述了LIBS技术在土壤重金属As、Cd、Cr、Hg、Pb 和Zn等污染快速测量中的应用和仪器研究进展,分析了LIBS应用在该领域中存在的主要问题,对未来基于LIBS快速检测土壤重金属污染需要解决的定量测量和检测限等关键问题进行了探讨.     

Synthesis of alpha-L-threofuranosyl nucleoside triphosphates (tNTPs)

[structure: see text] The alpha-l-threofuranosyl nucleoside triphosphates of T, G, and D (tTTP, tGTP, and tDTP) were synthesized from the described 2'-O-DMT-protected derivatives using the Eckstein method, while the corresponding C derivative (tCTP) was prepared from the 2'-O-acetyl derivative. The prepared alpha-l-threofuranosyl nucleoside triphosphates, despite being one carbon shorter than the native 2'-deoxyfuranosyl nucleoside triphosphates, are effective substrates for selected DNA polymerases.     

Kinetic analysis of an efficient DNA-dependent TNA polymerase

alpha-l-Threofuranosyl nucleoside triphosphates (tNTPs) are tetrafuranose nucleoside derivatives and potential progenitors of present-day beta-d-2'-deoxyribofuranosyl nucleoside triphosphates (dNTPs). Therminator DNA polymerase, a variant of the 9 degrees N DNA polymerase, is an efficient DNA-directed threosyl nucleic acid (TNA) polymerase. Here we report a detailed kinetic comparison of Therminator-catalyzed TNA and DNA syntheses. We examined the rate of single-nucleotide incorporation for all four tNTPs and dNTPs from a DNA primer-template complex and carried out parallel experiments with a chimeric DNA-TNA primer-DNA template containing five TNA residues at the primer 3'-terminus. Remarkably, no drop in the rate of TNA incorporation was observed in comparing the DNA-TNA primer to the all-DNA primer, suggesting that few primer-enzyme contacts are lost with a TNA primer. Moreover, comparison of the catalytic efficiency of TNA synthesis relative to DNA synthesis at the downstream positions reveals a difference of no greater than 5-fold in favor of the natural DNA substrate. This disparity becomes negligible when the TNA synthesis reaction mixture is supplemented with 1.25 mM MnCl(2). These results indicate that Therminator DNA polymerase can recognize both a TNA primer and tNTP substrates and is an effective catalyst of TNA polymerization despite changes in the geometry of the reactants.     

加速度计智能化检测系统设计研究

本文对部队现役装备及测试体制进行了分析研究，设计了加速度计（ＰＩ－ＧＡ）智能化检测系统，并在系统中加入了故障自诊断功能。     

有机涂层环境适应性研究进展

综述了有机涂层自然环境试验方法和实验室加速试验方法。自然环境试验方法主要有大气环境试验和海水环境试验;实验室加速试验方法不但包括模拟太阳光、热、湿热、盐雾等环境的实验室试验,还有综合模拟试验。还介绍了检测有机涂层老化的宏观分析方法、微观分析方法和电化学分析方法。其中宏观分析方法主要介绍了涂层附着力试验方法,微观分析方法则主要介绍了扫描电镜(SEM)、X射线光电子能谱仪(XPS)、傅里叶红外光谱(FTIR)及电化学交流阻抗谱法(EIS)。讨论了近年发展起来的有机涂层老化的各种机理,例如自由基降解的光老化降解机理,亲水性基团的水降解机理,热氧机理,臭氧及污染物影响的老化机理等。