Integración de visualización científica molecular en el salón de clases

For some years, Chemistry teachers have used scientific visualization software of molecular models in computing rooms and chemistry laboratories for educational purposes. However, its application in classrooms has been limited. This article describes the integration and use of computer programs for scientific molecular visualization in a traditional classroom. We consider that the improvement of technical aspects of their application and use (usability) has a direct effect on students' understanding of molecular structures (including students' extrinsic motivation), among other factors. Consequently, we developed a guide for the integration of hardware and software of molecular visualization for its use in the classroom

How Sn(IV) Influences on the Reaction Mechanism of 11, <i>tri</i>-Butyl <i>p</i>-Coumarate and Its <i>tri</i>-Butyl-tin <i>p</i>-Coumarate Considering the Solvent Effect: A DFT Level Study

Antioxidants are molecules that neutralize free radicals. In general, the reaction mechanisms of antioxidants are well known. The main reaction mechanisms of antioxidants are electron transfer (ET), hydrogen transfer (HT), and radical adduction formation (RAF). The study of these mechanisms is helpful in understanding how antioxidants control high free radical levels in the cell. There are many studies focused on determining the main mechanism of an antioxidant to neutralize a wide spectrum of radicals, mainly reactive oxygen species (ROS)-type radicals. Most of these antioxidants are polyphenol-type compounds. Some esters, amides, and metal antioxidants have shown antioxidant activity, but there are few experimental and theoretical studies about the antioxidant reaction mechanism of these compounds. In this work, we show the reaction mechanism proposed for two esters, 11, tri-butyl p-coumarate and its tri-butyl-tin p-coumarate counterpart, using Sn(IV). We show how Sn(IV) increases the electron transfer in polar media and the H transfer in non-polar media. Even though the nature of esters could be polar or non-polar compounds, the antioxidant activity is good for the Sn(IV)-p-coumarate complex in non-polar media

Estudio de usabilidad de visualización molecular educativa en un teléfono inteligente

Chemistry students have difficulty understanding molecular structures and their functions. To aide their comprehension, molecular visualization software has been developed to run on smart phones, but in order to positively influence learning it must have a high degree of usability (usability measures how software is used in terms of efficiency, efficacy and satisfaction). This paper describes a usability study of molecular visualization software running on a smart phone, where chemistry students analyzed molecular models. Results showed very good usability and 95% of students wanted to use it in further classes

Lactobacillus plantarum WCFS1 β-Fructosidase: Evidence for an Open Funnel-Like Channel Through the Catalytic Domain with Importance for the Substrate Selectivity

β-Fructosidase, a glycoside hydrolase of a biotechnologically important strain, was studied for its biochemical, physicochemical, and three-dimensional structure characteristics. This enzyme was heterologously expressed in Escherichia coli as a C-terminal His-tagged protein (SacB). β-Fructosidase catalyzes the cleavage of glycoside bonds toward certain carbohydrates with β-fructofuranosyl linkages; however, SacB exhibited selectivity toward sucrose and an optimum activity at pH 6.0–6.5 and 37 °C. In such optimum enzymatic activity conditions, the SacB was commonly observed as a monodisperse protein by dynamic light scattering (DLS). As β-fructosidase belongs to glycoside hydrolase family 32 (GH32), a β-sandwich and a five-bladed β-propeller domain are typical predicted folds in its structure. Docking and molecular dynamic simulations revealed for the first time a funnel-like channel perfectly exposed in the β-propeller domain of the Lactobacillus plantarum β-fructosidase (this allows the interaction between its entire catalytic triad and substrates that are larger than sucrose). In contrast, SacB showed a closed central tunnel collaterally induced by its His-tag