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  • Author or Editor: W. Zielenkiewicz x
  • Chemistry and Chemical Engineering x
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Abstract  

Heat effects and densities of hen egg lysozyme in the phosphate buffer at pH 8.8 and various NaCl concentrations were determined at 25°C by LKB 10700-2 microcalorimeter and an Anton Paar 60/602 densimeter. The relation between the changes of the enthalpy and apparent molar volumes vs. molality of NaCl were determined. The data are discussed together with the data obtained previously for hen egg lysozyme solutions with NaCl salt in Na-acetate buffer pH 4.2.

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Summary Heat effects and densities of bovine albumin solutions in Na-acetate buffer pH 4.2 at various NaCl, Li2SO4 and (NH4)2SO4 concentrations were determined by a LKB 10700-2 microcalorimeter and an Anton Paar 60/602 densimeter (25°C). The density measurements were made after 1 and 48 h of the dissolution of bovine albumin in the buffer. The correlations between the changes of the enthalpy of salting and apparent molar volumes vs. concentrations of salts were determined.

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Abstract  

The work describes the development in calorimetric studies on the aggregation process of simple globular proteins solutions induced by the presence of electrolytes. It also provides information on theoretical models and experimental methods applied to the examination of those processes.

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The basis of the determination of mathematical models of calorimetic systems is presented. Examples of applications of these models are given for the elaboration of a classification of calorimetric systems; the analysis of the course of heat effects in calorimeters; the analysis of dynamic properties: and the analysis of total heat effects and thermokinetics. Special attention is paid to the application of the multi-body method for the construction of mathematical models of calorimetic systems.

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In the present paper the dynamic properties of nonisothermal-nonadiabatic calorimeters have been analysed. In these calorimeters the thermal effect produced is partly accumulated in the calorimetric vessel, and partly transmitted to the shield with constant temperature. The generalized equation of the heat balance and the equation of the dynamics have been given for this type of calorimeter. The dependence between the course of the thermal effectQ in timet as a function of the temperature changesν of the calorimeter has been presented. DependencesQ(t)=f[ν(t)] for a calorimeter with different domain configurations distinguished in it, and with different mutual locations of heat sources and temperature sensor have been given. Practical application of the considerations presented has been given.

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Abstract  

Enthalpy of solution, ΔH sol o , enthalpy of sublimation, ΔH subl o , apparent partial molar volume and heat capacities,V 2 o andC p,2 o were determined for aqueous solutions of thirty alkylated derivatives of uracyl and adenine, eight derivatives of cytosine and guanine. Calculated accessible surface areas and molar volumes are presented, too. The values of enthalpy of solution, enthalpy of sublimation can be useful in the studies on the nature of interaction between these compounds and water molecules. Apparent partial molar volume and heat capacity give a new aspect on hydrophob properties of the examined nucleic acid base derivatives.

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Abstract  

Classification based on thermal properties and temperature conditions of heat transfer between proper calorimeter andsurrondings was presented. The dynamic properties of distinguished groups of calorimeters were determined.

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Abstract  

The results of determinations of the vapour pressures and enthalpies of sublimation of 1,N4-dimethyl-5-alkyl derivatives of cytosine are presented.

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Abstract  

The paper describes the fundamentals and applications of the thermal-dynamic analogy method to analyze the course of heat effects occurring in calorimeters. The method is based on introduction to the heat effect analysis of the terms, notions and mathematical procedures used in the steering theory. It was pointed out that this method can well be applied for elaboration of mathematical models of various types of calorimeters. These models determine both the heat properties of calorimeters as well as the dynamic ones.

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