Atomic-level characterization and cilostazol affinity of poly(lactic acid) nanoparticles conjugated with differentially charged hydrophilic molecules

Indexación: Scopus.M.F.M. acknowledges support from CONICYT-PFCHA/Doctorado Nacional/2014-21140225. M.M.M. thanks the FONCyT PICT-2015-2191, CONICET PIP 11220110100992, Secyt, Universidad Nacional de Cordoba. C.V. acknowledges support from CONICYT under FONDECYT #1161438 and BASAL Grant FB0807, MECESUP PMI-UAB1301, and H2020-MSCA-RISE-2016 #734801 MAGNAMED. The authors thank the High-Performance Computational Center (CCAD UNC) and Escuela de Ingeniería Civil en Bioinformática (Universidad de Talca) for access to supercomputers.Nanotherapeutics is a promising field for numerous diseases and represents the forefront of modern medicine. In the present work, full atomistic computer simulations were applied to study poly(lactic acid) (PLA) nanoparticles conjugated with polyethylene glycol (PEG). The formation of this complex system was simulated using the reactive polarizable force field (ReaxFF). A full picture of the morphology, charge and functional group distribution is given. We found that all terminal groups (carboxylic acid, methoxy and amino) are randomly distributed at the surface of the nanoparticles. The surface design of NPs requires that the charged groups must surround the surface region for an optimal functionalization/charge distribution, which is a key factor in determining physicochemical interactions with different biological molecules inside the organism. Another important point that was investigated was the encapsulation of drugs in these nanocarriers and the prediction of the polymer-drug interactions, which provided a better insight into structural features that could affect the effectiveness of drug loading. We employed blind docking to predict NP-drug affinity testing on an antiaggregant compound, cilostazol. The results suggest that the combination of molecular dynam ics ReaxFF simulations and blind docking techniques can be used as an explorative tool prior to experiments, which is useful for rational design of new drug delivery systems. © 2018 Matus et al.https://www.beilstein-journals.org/bjnano/articles/9/12

Una aproximación estadística al estudio de la carbonatación del hormigón

Carbonation is one of the factors that conditions reinforced concrete durability, while porosity is one of the parameters that determines the carbonation rate: as a rule, the greater the porosity, the higher the rate. While many papers have been published on the effect of CO2 penetration in the pore solutions of concretes prepared under different experimental conditions, the literature has yet to address the joint effect of the factors considered in concrete design, such as the water/cement (w/c) ratio, type of cement, type of aggregate and presence of admixtures. The present paper discusses the findings of a statistical study of the impact of the aforementioned factors on both system porosity and carbonation rate. The type of cement, individually and in its interaction with the rest of the factors, proved to be the major determinant in concrete carbonation.La carbonatación es uno de los factores que supedita la durabilidad del hormigón armado, siendo la porosidad uno de los parámetros que más condicionan la velocidad de carbonatación. Son muchos los trabajos que estudian el efecto de la penetración del CO2 en la solución de los poros de hormigones preparados bajo distintas condiciones experimentales, sin embargo, no se encuentran referencias que analicen de forma conjunta el efecto de ciertos factores como son la relación agua/cemento (a/c ratio), el tipo de cemento, el tipo de árido y la presencia de aditivos, normalmente consideradas a la hora de diseñar un hormigón. En este trabajo se discuten los resultados obtenidos tras realizar un estudio estadístico del efecto que tienen los factores previamente mencionados, tanto en la porosidad de estos sistemas como en su nivel de carbonatación. El cemento tanto de manera individual como en sus interacciones con el resto de los factores es el factor que mas afecta a la carbonatación del hormigón

Concentrations of total phenols and antioxidant activity in apple do not differ between conventional and organic orchard Management

Reprint Address: Yuri, JA (reprint author), Talca Univ, Agr Sci Fac, Pomaceas Ctr, Talca, Chile.The apple is one of the most widely consumed fresh fruits in the world. It constitutes a major contribution of phytochemical compounds to the diet, which are associated with a reduced risk to develop degenerative diseases. The main objective of this study was to evaluate the effects of conventional and organic management of apple cultivation, the stage of development and sunburn damage on polyphenol concentrations, antioxidant activity and pigments in three apple cultivars. Two experiments were carried out during the 2009/2010 season to study (1) the effect of the type of management and the development stage of the fruit during the season on the concentration and content of total and specific phenolics, antioxidant activity in the whole fruit, and pigments (chlorophylls, carotenoids and anthocyanins) in the peel of cvs. Gala (Galaxy and Brookfield), Granny Smith and Fuji (Raku Raku and Stripped) and (2) the effect of the type of management and the presence of sunburn at harvest on phenolics concentrations and antioxidant activity in both the whole fruit and peel, as well as pigments in peel, in two cultivars. Phenolics concentrations and antioxidant activity increased in the First weeks of fruit development and then decreased until harvest. The concentration of chlorophyll and carotenoids tended to decrease throughout the season, while anthocyanin concentration increased. In the case of tissue damaged by sunburn, phenolics concentrations and antioxidant activity were higher in damaged fruit, while changes in pigment concentrations varied according to the cultivar. The practices of conventional and organic management did neither influence significantly phenolics and pigments concentrations and antioxidant activity, except at certain stages of fruit development

Platinum-group elements in the cores of potassium feldspar spherules from the Cretaceous-Tertiary boundary at Caravaca (Spain)

The abundant spherules present in the Cretaceous-Tertiary boundary layer at Caravaca are diagenetically transformed to potassium feldspar. Before our study no possible relicts of the precursor material had been reported. but in this paper we describe the presence of cores in these spherules that could represent a relict of the «unknown precursor». These cores are made up of C mixed with Si. Mg. AL Cr. Ca among other elements. Laser Ablation System analysis also reveals an enrichment in pe;E could suggest an extraterrestrial origin for this material. PI. Pd and Ir do not show a chondritic ratio: however. asevere modification of their concentration could be expected during the early diagenetic processes.Las esférulas existentes en la lámina de sedimento del tránsito Cretácico-Terciario de la sección de Caravaca han sido transformadas diagenéticamente a feldespato potásico. En este trabajo se describe la existencia de núcleos encontrados en el interior de las esférulas. los cuales' pueden representar relictos del material precursor. Dichos núcleos están constituidos por C. Si. Mg, AL Cr y Ca entre otros elementos. Se pone de relieve, por vez primera, su notable enriquecimiento en elementos del grupo del platino, cuyas relaciones no condríticas pueden ser debidas a la existencia de importantes modificaciones en su concentración inicial causadas por los procesos diagenéticos y por la existencia de materia orgánica

Análisis de los canales de vídeo de las asociaciones médicas españolas

Internet es la principal fuente de búsqueda de información y cada vez con más frecuencia contenidos sobre salud. Por esta razón, el objetivo principal de este trabajo es el de realizar un primer análisis de los contenidos audiovisuales que se encuentran en las plataformas de vídeo (YouTube) de las asociaciones médicas españolas. Para llevar a cabo esta investigación se ha seleccionado la muestra de análisis entre los clips de video de los canales de estas asociaciones y se ha analizado su contenido. Las principales conclusiones del estudio muestran que las asociaciones médicas utilizan sus canales para contenidos muy diversos.Internet is the main source of information search and increasingly frequent also health content. Therefore the main objective of this work is to perform an initial analysis of audiovisual content present in video platforms (YouTube) from the Spanish medical associations. To carry out this research it has been selected sample analysis between video clips channels from these associations and it has been analysed by their contents. The main conclusions of the study show that medical associations use their channels for very different content