RESUMO
In solution, the solvent determines the molecular conformation and the chemical reaction viability and selectivity. When solvent-solute and solvent-solvent interactions present similar strengths, explicit salvation is the best way to describe a system. The problem to solve is how big the explicit shell should be. In this paper, we want to answer one of the fundamental questions in the implementation of explicit solvation, exactly how many solvent molecules should be added and where they should be placed. Here we determine the first solvent sphere around a molecule and describe how it controls the conformation and selectivity of a selected reaction. NMR experiments were carried out to identify the number of solvent molecules around the solute that constitutes the first solvent sphere, and the interaction between this solvent sphere and the solute was detected using DFT and QTAIM calculations. A new approach to the solvation energy is presented. Finally, we established the role of solvent molecules in the conformation of the solute and in the transition states that produce the two possible products of the reaction.
RESUMO
Purpose of Review: In the midst of the COVID-19 pandemic, several academic studies have emerged that explore the importance of vitamin D in the development of the SARS-CoV2 infection. The basis of this interest comes from the established effect vitamin D status has on other acute respiratory infections, such as influenza. This article aims to determine the role and effect of vitamin D serum concentration in the prevalence and severity of COVID-19. Recent Findings: Several observational studies have demonstrated that suboptimal levels of vitamin D serum concentrations can significantly increase the risk of developing COVID-19 and lead to a more severe symptomatology. One study suggests, however, that supplementation of vitamin D could potentially increase the incidence of mortality in COVID-19 patients. Summary: Vitamin D status could have an influential role in the development and progression of SARS-CoV2 infection. Further studies are warranted to understand fully the veracity and the extent of this association.