水/TX-100/正己醇/正辛烷反相微乳液的物化性质

运用微量热计（Microcalorimeter）,傅立叶变换红外（FT-IR）,对水／TX-100／正己醇／正辛烷反相微乳液体系的形成过程及水的微结构进行了研究．微量热结果表明该反相微乳液的形成过程为一放热过程,且为两步反应．第一步为TX-100单体中的聚氧乙烯醚键与水分子形成氢键的过程,然后是“包裹”在反相胶束中的聚氧乙烯醚键与H2O分子形成氢键的过程,这两步反应之间存在时间差,焓变在该反相微乳液的形成过程中起着主要作用．含水量不同时,体系分别形成结合水、束缚水和自由水,并用FT-IR对此加以证实,FT-IR测试结果表明结合水、束缚水和自由水羟基吸收峰分别位于3400±20cm-1、3550±20cm-1、3220±20cm-1,在反相微乳液中脂肪醚位于比芳基醚大的极性区域,因而先于芳基醚与水作用形成氢键．     

α-、β-环糊精和十二烷基三甲基溴化铵主-客体包合作用的微量热研究

在298．15K下,用微量热法测定了α-、β-环糊精与表面活性剂十二烷基三甲基溴化铵在水溶液中包合作用的热效应。从α-、β-环糊精的微观结构出发讨论了主-客体的结合模式以及热力学数据的差异。     

牛血清白蛋白与金霉素结合反应的机制研究

以光谱技术与微量热技术相结合的方法研究水溶液中金霉素与牛血清白蛋白分子间结合作用的热力学性质 .荧光猝灭法测得该反应的结合常数K =2 .0 9× 10 5L/mol,结合位点数n =1.75 ,微量法测得反应的焓变△rHm=- 17.5 0kJ/mol;依据Forster非辐射能量转移机制 ,得到授体 受体间的结合距离 (r1=1.6 7nm ,r2 =1.4 6nm)和能量转移效率 (E1=0 .4 1,E2 =0 .6 6 ) .金霉素与牛血清白蛋白分子间有较强的结合作用 ,且结合力以疏水作用为主 .     

Comparison of microbial activity in some Brazilian soils by microcalorimetric and respirometric methods

The microbial activity in a Rhodic eutrudox (R), a Typic eutrudox (V) and a Quartzipsamment (Q) was monitored by respirometric and calorimetric methods. CO₂ evolution was monitored for 98 days by titrimetry and conductimetry for control amended samples (A) with 25% of cattle manure (E), municipal refuse compost (L), earthworm casts (H) or 1.25 kg ha⁻¹ of trifluralin (T). Average values of all treatments through respiration at the end of the incubation period were 5.24±0.34, 6.13±0.31 and 6.50±0.33, in mg CO₂ g⁻¹ soil, for R, V and Q, respectively, by titrimetry and 8.89±0.44, 10.41±0.54 and 10.41±0.52, in mg CO₂ g⁻¹ soil, for R, V and Q, respectively, for conductimetry. Excellent correlation (r=1.00) between titrimetry and conductimetry was observed. The decreasing order for respiration was E, H, L and T. After each incubation time, the conductimetric values were higher than those for titrimetry, for all treatments of these Brazilian soils. Average values of the exothermic thermal effect were: 0.58±0.02, 0.60±0.02 and 0.67±0.01 kJ g⁻¹ soil, for R, V and Q, respectively, for 103 days. A significant correlation coefficient of 0.91 and P<0.0001 between calorimetric and respirometric values over 98 days was observed. Based on the obtained calorimetric results, it can be proposed that this technique should be as a useful analytical method for determining the microbial activity in soils.     

Kinetics and thermodynamics of the attack of fluorapatite by a mixture of sulfuric and phosphoric acids at 55 °C

A calorimetric study of kinetics and thermodynamics of the attack of a synthetic fluorapatite by a mixture of sulfuric and phosphoric acids is undertaken at 55 °C. The global enthalpy of the attack equals −409.3 kJ/mol. The recorded thermograms show two peaks leading to calcium sulfate hemihydrate and dihydrate, respectively. The deconvoluted curves were analysed iteratively. A kinetic mechanism based on simultaneous reactions has been proposed for the first peak and confirmed thermochemically by comparing the enthalpies deduced from iteration and that determined from experimental and calculated routes. The second peak of the thermogram was attributed to transformation of calcium sulfate hemihydrate into gypsum according to a dissolution/precipitation scheme. These phenomena are of order one and two, respectively.     

线粒体体外代谢热动力学研究

线粒体是细胞重要的细胞器之一，有细胞的“能源工厂”之称．因为线粒体内有许多酶，是特殊的酶催化氧化反应的场所山；所有动、植物细胞的线粒体都能通过各种营养物的氧化而产生“富能”物质ATP．采用一定的技术可将线粒体从细胞中分离出来，分离出来的线粒体中的酶系统还有一定的活性，而且线粒体内也有一定的营养物质，这样酶系统就能利用这些营养物进行代谢，从而释放出一定的能量．我们用微量热法对两种鱼肝脏线粒体进行了测量，发现线粒体代谢过程分四个阶段：停滞期、活性恢复期、稳定期、活性衰减期．在活性恢复期和活性衰减期，…     

微量热法研究黄嘌呤氧化酶反应

在热导工热量计双参数理论模型的基础上，建立了较快酶仲反应研究的双参数初始速度法的热动力学模型，用微量热法研究了黄嘌呤氧化酶催化氧化黄嘌呤的热动力学，该较快酶促反应遵循Ｍｉｃｈａｅｌｉｓ－Ｍｅｎｔｅｎ这，在２９８．１５Ｋ和ＰＨ＝７．５时，其米氏常数为１．０４×１０＾－３ｍｏｌ．Ｌ＾－１，与文献结果相符。     

Microcalorimetry in the screening of discovery compounds and in the investigation of novel drug delivery systems

Calorimetry has for some time been proposed as a rapid method for determination of bioactivity. This paper describes the background to this application and describes how it has been extended to the study of bioassay techniques via microcalorimetry in the development of structure activity relationships (SARs). That SARs can be developed indicates that it is possible to guide drug synthetic strategy through the results of microcalorimetric investigations, and this approach is explored here. In an extension of this approach it is argued that microcalorimetry is well suited to the examination of novel drug delivery systems, allowing investigation of the capacity of drug delivery molecules to release the drug in the presence of a target organism.     

细菌生长的热动力学性质的研究

前文报导了大肠杆菌在不同培养基中生长的速率及热力学函数.本文在此基础上又测定了不同细菌在相同培养基中生长的规律.细菌生长是一系列非常复杂的过程,为便于研究,使复杂问题简单化,我们采取与过渡状态理论类似的模式进行处理,得出了一些热动力学函数,这些数据为进一步探讨这一复杂过程提供了有用的信息.     

Calorimetric determination of the effect of ammonium-iron(II) phosphate monohydrate on Rhodic Eutrudox Brazilian soil

The fertilizer NH₄FePO₄·H₂O (AIP) was synthesized under mild hydrothermal conditions to be applied on soils to prevent iron deficiencies. The effect of the addition of AIP on soil microbial activity was studied by calorimetry, determining both basal respiration and carbon mineralization by means of the addition of an external carbon source. Thermal analyses (TG and DSC) were also used to provide additional soil properties. The effect of different amounts of AIP on soil microbial activity was quantitatively analyzed by a mass and energy balance performed via the analysis of the power-time curves. These balances allowed determination of the impact of AIP on soil more rapidly than conventional methodologies. The increase in the amount of added AIP leads to a less efficient metabolism, probably due microbial competition for the nitrogen source provided by the AIP and for the carbon source.