34 research outputs found
Hypovitaminosis A: cofactor of deleterious clinic outcome in human being
Importante foco de atenção em SaĂşde PĂşblica tem sido a avaliação de determinados micronutrientes no ser humano, em especial aqueles que se encontram associados Ă vulnerabilidade orgânica, conseqĂĽente ao desiquilĂbrio ou Ă deficiĂŞncia desses micronutrientes. Entre os micronutrientes, a hipovitaminose A tem sido objeto de realce devido Ă significante prevalĂŞncia em populações de paĂses em desenvolvimento. Este artigo aborda a Vitamina A, enfocando seu metabolismo e as repercussões deletĂ©rias, decorrentes de sua deficiĂŞncia sobre o organismo, suas manifestações no ciclo gravidopuerperal, e sua interação em situações clĂnicas, especĂficas.An important focus of attention in Public Health has been micronutrient deficiency in human being because of the enhanced vulnerability of individuals to the effects of micronutrient deficiency or imbalance. Among all micronutrients deficiencies, vitamin A has been one of the most important public health problems, affecting a large percentage of people in developing countries. This article focus on a review of vitamin A metabolism, deleterious repercussions and association with several clinical and obstetrics conditions. It highlights hypovitaminosis A as cofactor of deleterious clinic outcome in human being
The iodide-catalyzed decomposition of hydrogen peroxide: mechanistic details of an old reaction as revealed by electrospray ionization mass spectrometry monitoring
Synthesis and density functional calculations of the new molecule-based magnet precursor [Fe(H2opba-i)(dmso)2]Cl
Structure and Dynamics of β-Cyclodextrin in Aqueous Solution at the Density-Functional Tight Binding Level â€
DFT Study of Hydrogen-Assisted Dissociation of CO by HCO, COH, and HCOH Formation on Fe(100)
DFT calculations using the GGA-PBE exchange correlation functional were used to investigate the effect of the hydrogen in the assisted CO dissociation on the Fe(100) surface. The formation mechanisms of the primary products CH, OH, CH2, and H2O involved in the Fischer-Tropsch synthesis have been studied. Three different routes were investigated passing through the HCO, COH, or HCOH intermediates. The energy barriers of the reactions were estimated using the nudged elastic band method (NEB). The energy profiles of assisted and double-assisted dissociations of CO are presented. The formation energies of HCO, COH, and HCOH intermediates are estimated to be endothermic with activation energies of 0.90, 1.07, and 2.13 eV, respectively. The formation of CH2 is energetically more favorable with the global reaction energy estimated to be -1.10 eV. The other CH, OH, and H2O intermediates have also endothermic formation energies with respect to the Fe(100)/(CO + H) system. The chemical bonding of the adsorbed intermediates and reactants was analyzed based on the population analysis, electron localization function, and pseudodifferential charge density. A comparison with direct CO dissociation leads to the conclusion that hydrogen-assisted processes constitute viable routes for CO dissociation on Fe (100) and alkanes formation.Fil: Amaya Roncancio, Sebastian. Universidad Nacional de San Luis. Facultad de Ciencias FĂsico Matemáticas y Naturales. Departamento de FĂsica; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Linares, Daniel Humberto. Universidad Nacional de San Luis. Facultad de Ciencias FĂsico Matemáticas y Naturales. Departamento de FĂsica; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Duarte, HĂ©lio A.. Universidade Federal de Minas Gerais; BrasilFil: Sapag, Manuel Karim. Universidad Nacional de San Luis. Facultad de Ciencias FĂsico Matemáticas y Naturales. Departamento de FĂsica; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentin