Solvation parameters. Part 5: physicochemical interpretation of experimental solvent values for stationary phases of gas-liquid chromatography.

It has been demonstrated for a long time that in the particular case of gas-liquid chromatography (GLC), a linear free energy relationship (LFER) of five terms can be established, each term including a parameter of solute and a parameter of solvent. The nature of some of these parameters has been quite clearly identified, even if not always well predicted from the molecular structure. First of all, the five solute parameters: two involved in the hydrogen bonding and three in the Van der Waals forces; secondly, the two solvent parameters involved in hydrogen bonding.

Solvation parameters. 2. A simplified molecular topology to generate easily optimized values.

This paper describes a generalized method to establish the values of the five solvation parameters of solutes, which reflect, together with the five solvation parameters of solvents, the intermolecular forces involved in solutions and in some biological phenomena. The tool applied for this purpose is a simplified molecular topology (SMT), which principally takes into account, for each atom of a molecule, its nature, the nature of its bonds, and in some cases the nature of its first neighbors. The learning material used to weight the molecular features generated by SMT are two sets of experimentally determined solvation parameters, established in a previous work (Laffort et al.

Solvation parameters Part 1. Mutual improvements of several approaches and determination of two first sets of optimized values.

An improvement in the characterization and the determination of the solvation parameters allows, not only a better knowledge of solutions, but also of some biological phenomena. In this paper, we test several published data and approaches in the field of solubility and solvation parameters in two ways: (i) the mutual independence of the parameters and (ii) their ability to take into account recently published gas-liquid chromatographic data. From this enquiry it arises that the most suitable published values are those of Abraham concerning 314 solutes.

Application of the U and gamma' models in binary sweet taste mixtures.

The U and Gamma' models of sensory interactions, successfully applied in olfaction for several years, are tested here using data from published studies on sweetness. The models are subsequently tested on new data obtained in studies of binary mixtures of four sodium sulfamates. The U model allows for the estimation of a global interaction, whereas the Gamma' model allows for the distinction between that which is due to an intrinsic interaction in the mixture itself and that which may be due to the power function exponents in the mixture.

[Aortic atheroma: not a sensitive indicators for coronary artery disease in patients with mitral valve disease].

Aortic atheroma detected by transoesophageal echocardiography has been reported to be a good prognostic marker for coronary disease on angiography. The value of this detection in valvular heart disease would be to avoid preoperative coronary angiography in asymptomatic patients. The aim of this study was to assess the prognostic value of aortic atheroma in a population with a low prevalence of coronary artery disease in whom transoesophageal echocardiography was systematically performed.