Luis Barraza Rodriguez | Universidad del Atlantico (original) (raw)
Address: Barranquilla, Atlántico, Colombia
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Papers by Luis Barraza Rodriguez
Immunopharmacology and Immunotoxicology, 2009
2009)'Gossypol induced apoptosis of polymorphonuclear leukocytes and monocytes: Involvement of mi... more 2009)'Gossypol induced apoptosis of polymorphonuclear leukocytes and monocytes: Involvement of mitochondrial pathway and reactive oxygen species',Immunopharmacology and Immunotoxicology,31:2,320 -330
Journal of Physics B-atomic Molecular and Optical Physics, 2011
We have performed semi-empirical as well as density functional theory calculations in order to an... more We have performed semi-empirical as well as density functional theory calculations in order to analyse the hydration properties of both bare C60 and highly hydroxylated C60(OH)26 fullerenes. In all of our calculations, a total of 42 and 98 water molecules are always surrounding our here-considered carbon nanostructures. We found different wetting properties as a function of the chemical composition and structure of the OH-molecular over-layer covering the fullerene surface. In the case of bare C60, water adsorption reveals that the H2O species are not uniformly arranged around the carbon network but rather forms water droplets of different sizes, clearly revealing the hydrophobic nature of the C60 structure. In contrast, in the polyhydroxylated C60(OH)26 fullerenes, the degree of wetting is strongly influenced by the precise location of the hydroxyl groups. We found that different adsorbed configurations for the OH-molecular coating can lead to the formation of partially hydrated or completely covered C60(OH)26 compounds, a result that could be used to synthesize fullerene materials with different degrees of wettability. By comparing the relative stability of our hydroxylated structures in both bare and hydrated conditions we obtain that the energy ordering of the C60(OH)26 isomers can change in the presence of water. The radial distribution function of our hydrated fullerenes reveals that water near these kinds of surfaces is densely packed. In fact, by counting the number of H2O molecules which are adsorbed, by means of hydrogen bonds, to the surface of our more stable C60(OH)26 isomer, we found that it varies in the range of 5-10, in good agreement with experiments. Finally, by comparing the calculated optical absorption spectra of various C60(OH)26 structures in the presence and absence of water molecules, we note that only slight variations in the position and intensity of the electronic excitations are found, indicating that their vacuum optical properties are more or less preserved in aqueous environments.
Immunopharmacology and Immunotoxicology, 2009
2009)'Gossypol induced apoptosis of polymorphonuclear leukocytes and monocytes: Involvement of mi... more 2009)'Gossypol induced apoptosis of polymorphonuclear leukocytes and monocytes: Involvement of mitochondrial pathway and reactive oxygen species',Immunopharmacology and Immunotoxicology,31:2,320 -330
Journal of Physics B-atomic Molecular and Optical Physics, 2011
We have performed semi-empirical as well as density functional theory calculations in order to an... more We have performed semi-empirical as well as density functional theory calculations in order to analyse the hydration properties of both bare C60 and highly hydroxylated C60(OH)26 fullerenes. In all of our calculations, a total of 42 and 98 water molecules are always surrounding our here-considered carbon nanostructures. We found different wetting properties as a function of the chemical composition and structure of the OH-molecular over-layer covering the fullerene surface. In the case of bare C60, water adsorption reveals that the H2O species are not uniformly arranged around the carbon network but rather forms water droplets of different sizes, clearly revealing the hydrophobic nature of the C60 structure. In contrast, in the polyhydroxylated C60(OH)26 fullerenes, the degree of wetting is strongly influenced by the precise location of the hydroxyl groups. We found that different adsorbed configurations for the OH-molecular coating can lead to the formation of partially hydrated or completely covered C60(OH)26 compounds, a result that could be used to synthesize fullerene materials with different degrees of wettability. By comparing the relative stability of our hydroxylated structures in both bare and hydrated conditions we obtain that the energy ordering of the C60(OH)26 isomers can change in the presence of water. The radial distribution function of our hydrated fullerenes reveals that water near these kinds of surfaces is densely packed. In fact, by counting the number of H2O molecules which are adsorbed, by means of hydrogen bonds, to the surface of our more stable C60(OH)26 isomer, we found that it varies in the range of 5-10, in good agreement with experiments. Finally, by comparing the calculated optical absorption spectra of various C60(OH)26 structures in the presence and absence of water molecules, we note that only slight variations in the position and intensity of the electronic excitations are found, indicating that their vacuum optical properties are more or less preserved in aqueous environments.