Artículos y presentaciones en Congresos
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Examinando Artículos y presentaciones en Congresos por Autor "Castro, Eduardo A."
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Acceso Abierto Improved molecular descriptors based on the optimization of correlation weights of local graph invariants(MDPI (Multidisciplinary Digital Publishing Institute), 2001) Krenkel, Germán; Castro, Eduardo A.; Toropov, Andrey A.We report the calculation of boiling points for several alkyl alcohols through the use of improved molecular descriptors based on the optimization of correlation weights of local invariants of graphs. As local invariants we have used the presence of different chemical elements (i.e. C, H, and O) and the existence of different vertex degree values (i.e. 1, 2, 3 and 4). The inherent flexibility of the chosen molecular descriptor seems to be rather suitable to obtain satisfactory enough predictions of the property under study. Comparison with other similar approximation reveals a very good behavior of the present method. The use of higher order polynomials do not seem to be necessary to improve results regarding the simple linear fitting equations. Some possible future extensions are pointed out in order to achieve a more definitive conclusion about this approximation. - Artículo
Acceso Abierto Maximum topological distances based indices as molecular descriptors for QSPR. 4. Modeling the enthalpy of formation of hydrocarbons from elements(MDPI (Multidisciplinary Digital Publishing Institute), 2001) Mercader, Andrés; Castro, Eduardo A.; Toropov, Andrey A.The enthalpy of formation of a set of 60 hydroarbons is calculated on the basis of topological descriptors defined from the distance and detour matrices within the realm of the QSAR/QSPR theory. Linear and non-linear polynomials fittings are made and results show the need to resort to higher-order regression equations in order to get better concordances between theoretical results and experimental available data. Besides, topological indices computed from maximum order distances seems to yield rather satisfactory predictions of heats of formation for hydrocarbons. - Artículo
Acceso Abierto Structure-toxicity relationships for aliphatic compounds based on Correlation Weighting of Local Graph Invariants(MDPI (Multidisciplinary Digital Publishing Institute), 2003) Toropov, Andrey A.; Duchowicz, Pablo Román; Castro, Eduardo A.Quantitative Structure-Activity Relationships based on molecular descriptors calculated with Correlation Weights of Local Graph Invariants were developed to model the toxicity of aliphatic compounds to the 50% population growth inhibition. The relationships were computed on the basis of Labeled Hydrogen- Filled Graphs and correlation weights were obtained by an optimization to render as large as possible correlation coefficients between log(IGC 50-1) and descriptors calculated with correlation weights. Morgan extended connectivity indices of zero, first, and second orders, paths of lengths two and three and valence shells of second and third ranges have been tested as local invariants of the Labeled Hydrogen-Filled Graphs. The best quantitative relationship obtained from the optimization of correlation weights is that one based on the valence shell of range two. First, second, and third order fitting equations were determined and statistical results are better than other similar data for the same molecular set.