Importance of Molecular Simulation for Studying Structural Properties

Abstract The importance of molecular simulation is due to its application in different subjects as such as drug design, computational biology and materials science for studying molecular systems ranging from small chemical systems to large biological molecules and material assemblies. Some properties of molecular simulation are, quantitative structure-activity relationships (QSARs) which establish a quantitative relationship between chemical structures and their properties (structural and physicochemical), and this contributes to assisting and guiding the design and the selection of potent and safe drug candidates. The molecular electrostatic potential (MESP) is the potential energy of a proton at a particular location near a molecule, which correlates with dipole moment, electronegativity, and partial charges. MESP are valuable in computer-aided-drug-design because they help in optimization of electrostatic interactions between the protein and the ligand. These surfaces can be used to compare different inhibitors with substrates or transitions states of the reaction. FTIR technique is applied to obtain different functional groups present in the molecule or reaction. Besides, we can realize several studies as for example, kinetics, absorption and others

Degradación fotocatalítica de ácido 2,4-diclorofenoxiacético, 4-clorofenol y fenol en medio acuoso utilizando materiales de TiO2 y TiO2-SnO2

El fotocatalizador que exhibió la mejor actividad catalítica fue el que contiene1%molde estaño comparado con 0.1,0.5, 3 y 5%mol de estaño y las referencias de TiO2y SnO2.En la segunday terceraparte del trabajose muestran los resultados delosfotocatalizadores deTiO2dopadoscon1, 3 y 5%mol de SnO2utilizandodos distintosprecursores(SnCl2◦2H2O y SnCl4◦5H2O)que proporcionaniones estaño con distinto estado de oxidación (Sn2+y Sn4+).Las muestras de TiO2dopadas conSn2+y Sn4+,presentaron modificaciones con respecto a *Degradar: Trasformar una sustancia compleja en otra u otras de estructura más sencilla. nuestra referencia de TiO2. La evaluación fotocatalítica de ambas series de fotocatalizadores se realizómediante la mineralizaciónde 4-clorofenol y fenol bajo luz UV. Ambas series muestran queel fotocatalizadormás activo,en la mineralización de los contaminantes antes mencionados,es el que contiene1%mol comparado con 3 y 5%mol (Sn2+y Sn4+) y con las referenciasde TiO2y SnO2.Todas las reacciones en los distintos sistemas fueron seguidas por medio de espectroscopia UV-Vis y por carbón orgánico total(COT). Los resultados obtenidos dela caracterización en los distintos sistemas fueron propuestoslosposiblesmecanismosde reacción por el cual se degradanlos contaminantes orgánicosutilizandola muestra más activa.Los tratamientos al degradar*contaminantes orgánicos en aguas residuales producidos para laelaboración de fármacos, cosméticos, colorantes sintéticos, petroquímicos, pesticidas y fungicidas, como el ácido 2,4-diclorofenoxiacético(2,4-D), 4-clorofenol y fenol han sido insuficientespara su total eliminación en medio acuoso. En este trabajo de tesis se presenta el estudio de la eliminación de estos contaminantes utilizando fotocatalizadores de TiO2dopado con SnO2obteniendo resultados importantes.En el presentetrabajo se sintetizarondistintos fotocatalizadores de dióxido de titanio (TiO2), dióxido de estaño (SnO2)y TiO2dopadoscon diferentes concentraciones molares(%mol)de SnO2, utilizando diferentesprecursores (alcóxido y cloruros de estaño) mediante el método sol-gel.Las propiedades químicas, estructurales, texturales, morfológicas y ópticas de los múltiplesfotocatalizadoresantes mencionados fueron caracterizados por diferentestécnicas: Análisis termogravimétrico,Análisis térmico diferencial, Difracción de rayos-X,Refinamiento Rietveld, Espectroscopiade fotoelectrones deRayos-X, Espectroscopia Raman, Fisisorción de N2, Espectroscopia infrarroja con transformada de Fourier-Piridina,Espectroscopia de Reflectancia difusa (UV-Vis), Microscopia electrónica de barrido(SEM)y Microscopia electrónica de transmisiónde alta resolución(HRTEM). En la primera parte de este trabajo se describe la síntesis delos distintosmateriales de TiO2dopadocon 0.1, 0.5, 1, 3 y 5%mol de estaño utilizando tert-butóxidode estaño(IV)como fuente de estaño (Sn4+)y las referencias puras de TiO2y SnO2. La información obtenida,mediante las técnicas de caracterización enmuestras dopadas,exhibieron quelas propiedades de TiO2se perturbanpor la adiciónde Sn4+. La evaluación fotocatalítica esdeterminada por medio de la mineralizaciónde 2,4-D bajo luz UV

Bird Behaviour during Prey-Predator Interaction in a Tropical Forest in México

Birds emit alarm calls, considered as honest signals, because they communicate the presence of a predator or potential threat. We evaluated behavioural events of birds responding to vocal and visual stimuli of a nocturnal predator (black-and-white owl Ciccaba nigrolineata) and a diurnal predator (collared forest falcon Micrastur semitorquatus). We analysed variations in behavioural events seasonally (reproductive and nonbreeding) and by bird size, as well as their relationship with the vegetation structure and landscape. The study was performed during the breeding (March-May) and non-breeding seasons (February, June and July) of 2016 in Chiapas, Mexico. We used four transects with different vegetation types and land uses. The most frequent behavioural response by birds to the vocal stimuli of the black-and-white owl and the collared forest-falcons was vocal, during the breeding season, and small species responded the most to the stimuli (p = 0.008) and (p < 0.015), respectively. We identified two vegetation and two landscape variables associated in 36% of probability for the prey to respond to black-and-white owl vocal stimuli, three variables of vegetation and one of the landscape in 37% for the collared forest-falcon stimuli. Potential prey animals modify the behaviour, which allows them to detect, evade or confront a predator

Morphometric and molecular characterization of Kudoa encrasicoli n. sp. (Myxozoa: Myxosporea) from the European anchovy, Engraulis encrasicolus (L.) (Clupeiformes: Engraulidae)

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGThe European anchovy represents the main fisheries for countries in the Mediterranean and Black Sea basins. The skeletal muscle of 13 of 48 (27.1%) Engraulis encrasicolus (L.) specimens from North East Atlantic waters (FAO 27.8.c) was found infected with interfibrillar elongated plasmodia (130-980 µm in length) containing mature myxospores belonging to the genus Kudoa Meglitsch, 1947. No flesh softening was found associated with infection. Fresh myxospores were 10.8 ± 0.7 (9.1-12.3) µm in width 1, 11.3 ± 0.9 (9.5-13.4) µm in width 2, 6.7 ± 0.4 (5.8-7.4) µm in thickness, and 6.9 ± 0.5 (5.8-7.5) µm in length. They were almost stellate in apical view having three pointed-edged shell valves bearing three small polar capsules equal in size 5.0 ± 0.3 (4.4-5.4) μm long and 2.4 ± 0.2 (2.0-3.0) μm wide, and one rounded- to rarely bluntly pointed-edged shell valve bearing a large and particularly wide polar capsule 6.8 ± 0.4 (5.9-7.6) μm long and 4.1 ± 0.2 (3.6-4.4) μm wide. Morphological and morphometrical comparisons between these myxospores and those of Kudoa thyrsites (Gilchrist, 1923) from the clupeid Sardina pilchardus (Walbaum) (North East Atlantic waters, FAO 27.9.a), with which exhibited a similarity of 98.9% and 96.2% using SSU and LSU rDNA sequences, respectively, support the creation of Kudoa encrasicoli n. sp. Morphometrical analysis of the polar capsules of flattened myxospores is suggested as a useful approach to differentiate phylogenetically related kudoids with stellate or almost stellate myxospores bearing four polar capsules.Fundação para a Ciência e a Tecnologia | Ref. UIDB/04423/2020 442Fundação para a Ciência e a Tecnologia | Ref. UIDP/04423/2020Fundação para a Ciência e a Tecnologia | Ref. PTDC/BIA-BMA/6363/2020Xunta de Galici

Obtención y caracterización de almidón de plátano (Musa paradisiaca L.) acetilado a diferentes grados de sustitución

El almidon fue aislado de frutos inmaduros de plátano y fue modificado químicamente con anhídrido acético en la presencia de una base para mejorar las propiedades funcionales del almidón nativo. El almidón nativo primero reaccionó a 123ºC con 55,5 mL de anhídrido acético, con un tiempo de acetilación de 90 min. El máximo grado de sustitución bajo esas condiciones fue de 1,05. Fueron investigadas las propiedades térmicas del almidón modificado con el fin de determinar su potencial aplicación como polímero biodegradable para aplicaciones comerciales. Los gránulos de almidón fueron de forma oval y elongada con una longitud de 27,26 μm; la modificación mostró cambios grandes en el tamaño. Los cambios morfológicos fueron observados por lo menos en la región superficial de los gránulos. Un patrón de difracción de rayos X (RX) tipo C se presentó en el almidón nativo de plátano y algunos cambios fueron observados después de la acetilación

Development of Optical Waveguides Through Multiple-Energy Ion Implantations

In this chapter, we present information about the design, fabrication and characterization of optical waveguides obtained by using a protocol of multiple energy ion implantations. This protocol must provide an approach to produce optical waveguides with adequate features, such as dimensions, evanescent field and optical confinement. In general, optical waveguides can be improved by widening the optical barrier or waveguide core through multiple energy ion implantations. Design of optical waveguides must consider effects induced by the ion implantation process, such as modification of substrate density, polarizability and structure. Information will be presented about optical waveguides formed mainly in laser crystals (i.e., Nd:YAG, Nd:YVO4) using light ions such as H and He+ and heavy ions such as C2+. In general, these ions decrease the refractive index in the implanted area, producing a barrier that permits guiding in the region near the surface. Furthermore, information about nonlinear optical properties of channel waveguides containing metallic nanoparticles is presented. Composite materials containing metallic nanoparticles embedded in a dielectric matrix such as silica possess interesting properties due to surface plasmon resonance absorption features and the enhancement of the third-order nonlinear optical response. Therefore, nonlinear optical properties in composite waveguides can be used in all-optical switching devices

Metabolomic-Based Studies of the Intake of Virgin Olive Oil: A Comprehensive Review

Virgin olive oil (VOO) is a high-value product from the Mediterranean diet. Some health and nutritional benefits have been associated with its consumption, not only because of its monounsaturated-rich triacylglycerols but also due to its minor bioactive components. The search for specific metabolites related to VOO consumption may provide valuable information to identify the specific bioactive components and to understand possible molecular and metabolic mechanisms implicated in those health effects. In this regard, metabolomics, considered a key analytical tool in nutritional studies, offers a better understanding of the regulatory functions of food components on human nutrition, well-being, and health. For that reason, the aim of the present review is to summarize the available scientific evidence related to the metabolic effects of VOO or its minor bioactive compounds in human, animal, and in vitro studies using metabolomics approachesFEDER 2014–2020/Junta de Andalucía/ Consejería de Transformación económica, Industria, Conocimiento y Universidades.Project (B-AGR-257-UGR18

Changes in the frequency of food consumption and nutritional status in farmers of Yaguajay, central Cuba, 2017-2022

La crisis generada por la pandemia de COVID-19 afectó la alimentación y el estado de salud de trabajadores del sector agrícola. El objetivo de esta investigación es identificar cambios en la frecuencia de consumo de alimentos y el estado nutricional en 16 campesinos residentes en la comunidad rural La Picadora, teniendo en cuenta el impacto que la situación económica y epidemiológica pueden haber producido luego de la pandemia de COVID-19. Se realizó un estudio descriptivo en los mismos 16 individuos en octubre de 2017 y abril de 2022, que incluyó entrevistas, cuestionarios de frecuencia de consumo de alimentos y mediciones antropométricas. Las variables discretas iniciales (2017) y las finales (2022) se compararon mediante la prueba de rangos con signos de Wilcoxon y las variables continuas se contrastaron mediante la prueba t Student. La disminución de la frecuencia del consumo de pastas, carne de cerdo, vísceras, refrescos industriales y dulces y el aumento de la frecuencia de consumo de grasa vegetal fueron estadísticamente significativas. El peso, el índice de masa corporal y la circunferencia de la cintura aumentaron, mientras que la talla disminuyó, siendo significativos los cambios observados en la circunferencia de la cintura y la talla. Concluimos que la dieta en el 2022 fue menos variada que en el 2017. Cambios en el patrón de alimentación y en los modos y estilos de vida durante la pandemia de COVID-19 constituyeron factores de riesgo para el aumento de la adiposidad abdominal en campesinos normopesos y sobrepesos. Las mediciones antropométricas demostraron su utilidad para el monitoreo del estado nutricional de poblaciones rurales agrícolas.The crisis triggered by the COVID-19 pandemic affected the nutrition and general health status in the agricultural sector and its workforce. The objective of this research is to describe changes in food consumption frequency and nutritional status in 16 farmers from the rural community of La Picadora, taking into account that the impact of the economic and epidemiological situation may have produced changes during this period. A follow-up descriptive study was carried out between October 2017 and April 2022. This included interviews, food consumption frequency questionnaires, and anthropometric measurement. Discrete initial (2017) and final (2022) variables were compared using the Wilcoxon signed-rank statistical test and continuous variables were contrasted using the Student t test for paired samples. The differences were statistically significant regarding the decrease in the frequency of consumption of pasta, pork, organ meats, industrial soft drinks and sweets, and the increase in the frequency of consumption of vegetable fat. A trend of increased weight, body mass index, and waist circumference and decreased height was observed, with significant changes in height and waist circumference. Diet in 2022 was less diverse than in 2017. Changes in dietary pattern and lifestyles during the COVID-19 pandemic were identified as risk factors for increased central adiposity in normal-weight and overweight farmers. Anthropometric measurements proved useful in the assessment of nutritional status of rural agricultural populations.Asociación de Antropología Biológica Argentin

Accelerated and natural carbonation of concretes with internal curing and shrinkage/viscosity modifiers

Abstract In many parts of the world, corrosion of reinforcing steel in concrete induced by carbonation of the concrete continues to be a major durability concern. This paper investigates the accelerated and natural carbonation resistance of a set of seven concretes, specifically evaluating the effects of internal curing and/or shrinkage/viscosity modifiers on carbonation resistance. In addition to five different ordinary portland cement (OPC) concretes, two concretes containing 20 % of a Class F fly ash as replacement for cement on a mass basis are also evaluated. For all seven concrete mixtures, a good correlation between accelerated (lab) and natural (field) measured carbonation coefficients is observed. Conversely, there is less correlation observed between the specimens’ carbonation resistance and their respective 28 days compressive strengths, with the mixtures containing the shrinkage/viscosity modifier specifically exhibiting an anomalous behavior of higher carbonation resistance at lower strength levels. For both the accelerated and natural exposures, the lowest carbonation coefficients are obtained for two mixtures, one containing the shrinkage/viscosity modifier added in the mixing water and the other containing a solution of the same admixture used to pre-wet fine lightweight aggregate. Additionally, the fly ash mixtures exhibited a significantly higher carbonation coefficient in both exposures than their corresponding OPC concretes