毛细管电泳无胶筛分介质分离DNA的机理

快速、高效而灵敏的分离技术对于DNA的分析是至关重要的。使用无胶筛分介质的毛细管电泳是最重要的DNA分离技术之一,通常使用无交联的高分子溶液作为无胶筛分介质。本文在介绍高分子溶液理论的基础上,综述了DNA在毛细管电泳无胶筛分介质（缠结溶液和稀溶液）中的分离机理,主要包括Ogston筛分模型、各种修正的爬行模型、瞬态缠结偶合机理及其改进机理等。     

毛细管电泳无胶筛分介质分离DNA的机理

快速、高效而灵敏的分离技术对于DNA的分析是至关重要的。使用无胶筛分介质的毛细管电泳是最重要的DNA分离技术之一,通常使用无交联的高分子溶液作为无胶筛分介质。本文在介绍高分子溶液理论的基础上,综述了DNA在毛细管电泳无胶筛分介质(缠结溶液和稀溶液)中的分离机理,主要包括Ogston筛分模型、各种修正的爬行模型、瞬态缠结偶合机理及其改进机理等。     

毛细管电泳无胶筛分介质分离DNA的机理

快速、高效而灵敏的分离技术对于DNA的分析是至关重要的.使用无胶筛分介质的毛细管电泳是最重要的DNA分离技术之一,通常使用无交联的高分子溶液作为无胶筛分介质.本文在介绍高分子溶液理论的基础上,综述了DNA在毛细管电泳无胶筛分介质(缠结溶液和稀溶液)中的分离机理,主要包括Ogston筛分模型、各种修正的爬行模型、瞬态缠结偶合机理及其改进机理等.     

基于纤维素衍生物的毛细管无胶筛分电泳及其应用

毛细管无胶筛分电泳近年来取得了很大进展。本文综述了以纤维素衍生物作为筛分介质的毛细管无胶筛分电泳的研究进展,包括筛分理论,筛分体系模式,以及它在DNA、蛋白质分离方面的应用。     

聚环氧乙烷无胶筛分毛细管电泳分离宽分子量范围DNA片段

在无胶筛分毛细管电泳中,以聚环氧乙烷为筛分介质,用硅烷化处理的毛细管柱（31.2 cm×75 μm有效长度21.0 cm）分离DL5000 DNA Marker（DNA长度为100~5000 bp）,研究筛分介质浓度、缓冲液pH、分离电压和溴化乙锭浓度对分离双链DNA片段的影响,优化出分离100~5000 bp DNA片段的最佳条件。毛细管电泳的最佳条件为PEO浓度0.5%、缓冲液pH值8.0、电压12 kV、溴化乙锭浓度3.0 μg/mL。此条件下,对山梨醇脱氢酶基因（SDH）和乙烯受体基因（ETR1）的聚合酶链式反应（PCR）扩增产物同时检测,分离、鉴定效果良好。     

毛细管电泳聚乙烯吡咯烷酮与羟乙基纤维素混配无胶筛分介质分离DNA片段

本文报道了毛细管电泳聚乙烯吡咯烷酮与羟乙基纤维素混配无胶筛分介质分离较短的 p GEM7Zf(+) Hae DNA片段 (DNA长度为 1 8～ 675bp)。研究表明 ,在 1 %的羟乙基纤维素无胶筛分介质中 ,加入 2 %的聚乙烯吡咯烷酮能显著提高 DNA片段的分辨率和分离效率。在混配无胶筛分介质中 ,聚乙烯吡咯烷酮有两种作用 ,一是动态涂渍 ,降低毛细管内壁对 DNA片段与 DNA荧光插入试剂的吸附 ,改善分离效率 ;二是两种不同长度、性质的线性高分子能形成更为致密的“缠绕网络”,有利于较短的 DNA片段电泳分离。     

豚草聚合酶链反应产物的高效毛细管电泳检测

利用PE270A－HT型高效毛细管电泳仪,采用无胶筛分电泳,以羟丙基甲基纤维素（HPMC）为筛分介质,对三裂叶豚草（Ambrosia trifida L.)的聚合酶链反应（PCR）产物进行了分离分析,显示了高效、快速、无污染的毛细管电泳技术在植物DNA片段多态性分析方面的巨大的潜力。     

毛细管电泳聚乙烯吡咯烷酮与羟乙基纤维素混配无胶筛分介质分离DN …

本文报道了毛细电泳聚乙烯吡咯烷酮与羟乙基纤维素混配无胶筛分介质分离较短的ｐＧＥＭ７Ｚｆ（＋）－ＨａｅⅢＤＢＡ片段（ＤＮＡ长度为１８～６７５ｂｐ）。研究表明,在１％的羟乙基纤维素无胶筛分介质中,加入２％的聚乙烯吡咯迷酮能显著提高ＤＮＡ片段的分辨率和分离效率。在混配无胶筛分介质中,聚乙烯吡咯烷酮有两种作用,一是动态涂渍,降低毛细管内壁对ＤＮＡ片段与ＤＮＡ荧光插入试剂的吸附,改善分离效率;二是两种不同长     

样品稀释对毛细管电泳分离检测DNA片段的影响

通过理论推导和实验验证表明;适当稀释DNA样品溶液,采用流体力学进样或电动进样都不会较大地减低峰高,而DNA片段毛细管电泳的分离效率和分离度还能有所提高。采用稀释样品的方法可提高DNA样品的使用效率。采用羟乙基纤维素无胶筛分介质分离了DNA片段。用激光诱导荧光（氩离子激光器,488nm）电荷耦合器件检测。用低浓度的筛分介质（0．4％）分离了分子质量较大的ADNA－HindⅢ全部8个片段（12bp～23130bP）。用高浓度的筛分介质（1．6％）分离分子质量较小的pBR322－HaeⅢ22个片段（18bp～587bp）。     

毛细管无胶筛分电泳涂渍柱的制备和性能考察

对用于毛细管无胶筛分电泳的聚丙烯酰胺柱的材料、添加剂和工艺进行了一系列的优化，使所得制备柱可分离相差3个碱基对的DNA片段，柱效达1．6×105／m，迁移时间的RSD小于0.9％（n＝5），pH范围为2．5～8．5。     

国内光催化研究进展简述

分1975~1985, 1985~1995和1995~2012三个时期简要介绍了国内光催化研究进展, 主要侧重于光催化材料及其改性、应用和反应机理方面的研究进展, 并指出了当前光催化领域存在的一些重要问题和未来的发展趋势, 涉及到光解水、CO₂还原、环境净化和选择性有机合成等方面.     

青蒿素研究进展

青蒿素是目前治疗疟疾的特效药。本文对自青蒿素发现以来的最新研究进展进行了比较详尽的综述。内容包括: 青蒿素的发现及历史, 青蒿素的来源, 青蒿素的全合成,青蒿素的生物合成, 青蒿素衍生物以及植物组织培养生产青蒿素。     

Reactions in droplets in microfluidic channels

Fundamental and applied research in chemistry and biology benefits from opportunities provided by droplet-based microfluidic systems. These systems enable the miniaturization of reactions by compartmentalizing reactions in droplets of femoliter to microliter volumes. Compartmentalization in droplets provides rapid mixing of reagents, control of the timing of reactions on timescales from milliseconds to months, control of interfacial properties, and the ability to synthesize and transport solid reagents and products. Droplet-based microfluidics can help to enhance and accelerate chemical and biochemical screening, protein crystallization, enzymatic kinetics, and assays. Moreover, the control provided by droplets in microfluidic devices can lead to new scientific methods and insights.     

Interpretation of inorganic arsenic metabolism in humans in the light of observations made in vitro and in vivo in the rat

The toxicity of inorganic trivalent arsenic for living organisms is reduced by in vivo methylation of the element. In man, this biotransformation leads to the synthesis of monomethylarsonic (MMA) and dimethylarsinic (DMA) acids, which are efficiently eliminated in urine along with the unchanged form (As_i). In order to document the methylation process in humans, the kinetics of As_i, MMA and DMA elimination were studied in volunteers given a single dose of one of these three arsenicals or repeated doses of As_i. The arsenic methylation efficiency was also assessed in subjects acutely intoxicated with arsenic trioxide (As₂O₃) and in patients with liver diseases. Several observations in humans can be explained by the properties of the enzymic systems involved in the methylation process which we have characterized in vitro and in vivo in rats as follows: (1) production of As_i metabolites is catalyzed by an enzymic system whose activity is highest in liver cytosol; (2) different enzymic activities, using the same methyl group donor (S-adenosylmethionine), lead to the production of mono- and di-methylated derivatives which are excreted in urine as MMA and DMA; (3) dimethylating activity is highly sensitive to inhibition by excess of inorganic arsenic; (4) reduced glutathione concentration in liver moderates the arsenic methylation process through several mechanisms, e.g. stimulation of the first methylation reaction leading to MMA, facilitation of As_i uptake by hepatocytes, stimulation of the biliary excretion of the element, reduction of pentavalent forms before methylation, and protection of a reducing environment in the cells necessary to maintain the activity of the enzymic systems.     

Gemini表面活性剂合成进展

系统总结了近百种Gemini表面活性剂的合成路线和方法,并且按照其结构特点分门别类地进行比较和归纳,对今后Gemini表面活性剂的合成发展方向提出了一些看法,这对促进此类新颖表面活性剂的工业化进程将具有指导意义。     

Recent Advances in Analytical Methodology for in vivo Electrochemistry in Mammals

Electrochemistry is one of the most advanced techniques for monitoring neurochemical activities in the living brain because electrochemical approaches bear the advantageous features of high spatial and temporal resolutions, which facilitate its tremendous potential in investigating the highly spatially heterogeneous brain system and the fast dynamics of neurochemical activities. On the other hand, since brain is the most complicated organ in the sense of its numerous kinds of neurochemical species, high selectivity is always required for any analytical methods that approach the brain. In this review, we will discuss various electrochemical methodologies to achieve selective detection of neurochemicals in mammalian brain and the strategies developed mainly by our group towards selective monitoring of both electrochemically active and inactive neurochemicals. At the end, we will discuss possible solutions towards brain mapping of neurochemical species and combination of neurochemical detection strategy with electrophysiology as the direction of future development of electroanalysis in living brain.     

乙基香兰素研究前景

报导了近几十年来国内外关于乙基香兰素的研究进展与动态,并简单介绍了本文作者在该方面所取得的研究成果,参考文献33篇。     

Trends in education in analytical chemistry

Summary At the session of the WPAC of Fechem on education in analytical chemistry it was concluded that it is now essential to include chemometrics and basic knowledge of computers in all courses on analytical chemistry.

---

Tendenzen in der analytisch-chemischen Ausbildung

Zusammenfassung Bei einer Tagung der WPAC über die Lehre auf dem Gebiet der analytischen Chemie wurde bei der Betrachtung neuer Aspekte festgestellt, daß vor allem Chemometrie und Grundkenntnisse in Computertechnik in die Ausbildung aufgenommen werden sollten.

     

钙与人体及临床

钙是宏量元素，是人体中含量较高的元素之一，体内99％的钙构成骨骼和牙齿以及维持骨骼结构，1％的钙调节人体重要生理功能。钙的含量过高或过低都与许多疾病有关，只有保持一种平衡状态，才能使机体处于正常环境。     

AGET ATRP in the Presence of Air in Miniemulsion and in Bulk

Summary: The recently developed initiation system, activators generated by electron transfer (AGET), is used in atom transfer radical polymerization (ATRP) in the presence of a limited amount of air. Ascorbic acid and tin(II ) 2‐ethylhexanoate are used as reducing agents in miniemulsion and bulk, respectively. An excess of reducing agent consumes the oxygen present in the system and, therefore, provides a deoxygenated environment for ATRP. ATRP of butyl acrylate is successfully carried out in miniemulsion and in the presence of air. During polymerization the radical concentration remains constant. The polymerization reaches over 60% monomer conversion after 6 h, which results in polymers with a predetermined molecular weight = 14 000 g · mol⁻¹ and a low polydispersity ( = 1.23). AGET ATRP of styrene is also successful in bulk in the presence of air, as evidenced by linear semi‐logarithmic kinetics, which leads to polystyrene with an of 13 400 g · mol⁻¹ and a low polydispersity index ( = 1.14).

Appearance of miniemulsion before and after the reducing agent ascorbic acid was added (left); and GPC traces representing molecular weights during the AGET ATRP of BA in miniemulsion in the presence of air (right).