PLEs from virtual ethnography of social web

En este artículo se presenta una investigación exploratoria basada en la etnografía virtual desde un entorno de investigación y aprendizaje con nuevas tecnologías. La etnografía es un método de investigación cualitativo de las ciencias sociales que es usado principalmente en la antropología socio-cultural, donde tiene su fundamento teórico. El objetivo fue explorar la web 2.0 y sus herramientas desde la etnografía virtual. El método de investigación es basado en la etnografía virtual y la observación participante, la cual se realizó participando en comunidades virtuales y por medio de un blog y otras herramientas 2.0. El resultado de la experiencia etnográfica es un modelo descriptivo de la web 2.0 basado en un Entorno Personal de Aprendizaje (PLE).This article presents an exploratory research based on the virtual ethnography from an environment of research and learning including new technologies. The ethnography is a method of qualitative research of social sciences that is mainly used in the socio-cultural anthropology, where it has its theoretical basis. The target was to explore the web 2.0 and its tools. The process of participant observation is by means of a blog, other tools and virtual communities. The result is a descriptive model of the web 2.0 based on a Personal Learning Environment which developed in the ethnographic experience

Refractory onychomycosis due to Trichophyton rubrum: combination therapy with itraconazole and terbinafine

Objectives: Evaluate the efficacy and tolerability of itraconazole plus terbinafine for refractory onychomycosis. This is a prospective clinical trial. Patients with proven Trychophyton rubrum onychomycosis of toenails were enrolled; the treatment consisted of weekly administration: itraconazole 200mg/day and terbinafine 250mg/day, for four months. Results: Thirty-two patients with onychomycosis were studied. Twenty-eight cases had distal subungual onychomycosis and 4 total dystrophic onychomycosis. At the end of the follow-up 17/32 patients had clinical and mycologic cure (53.12%), 5 had clinical improvement only (15.6%), and 10 (31.2%) failed. Conclusion: Weekly alternate therapy with itraconazole + terbinafine represents a safe rescue treatment

Insights into the room temperature magnetism of ZnO/Co3O4 mixtures

The origin of room temperature (RT) ferromagneticlike behavior in ZnO-based diluted magnetic semiconductors is still an unclear topic. The present work concentrates on the appearance of RT magnetic moments in just mixed ZnO/Co3O4 mixtures without thermal treatment. In this study, it is shown that the magnetism seems to be related to surface reduction of the Co3O4 nanoparticles, in which, an antiferromagnetic Co3O4 nanoparticle (core) is surrounded by a CoO-like shell. This singular superficial magnetism has also been found in other mixtures with semiconductors such as TiO2 and insulators such as Al2O3

Immune modulation by inhibitors of the HO system

The heme oxygenase (HO) system involves three isoforms of this enzyme, HO-1, HO-2, and HO-3. The three of them display the same catalytic activity, oxidating the heme group to produce biliverdin, ferrous iron, and carbon monoxide (CO). HO-1 is the isoform most widely studied in proinflammatory diseases because treatments that overexpress this enzyme promote the generation of anti-inflammatory products. However, neonatal jaundice (hyperbilirubinemia) derived from HO overexpression led to the development of inhibitors, such as those based on metaloproto-and meso-porphyrins inhibitors with competitive activity. Further, non-competitive inhibitors have also been identified, such as synthetic and natural imidazole-dioxolane-based, small synthetic molecules, inhibitors of the enzyme regulation pathway, and genetic engineering using iRNA or CRISPR cas9. Despite most of the applications of the HO inhibitors being related to metabolic diseases, the beneficial effects of these molecules in immune-mediated diseases have also emerged. Different medical implications, including cancer, Alzheimer´s disease, and infections, are discussed in this article and as to how the selective inhibition of HO isoforms may contribute to the treatment of these ailments.Fil: Fernández Fierro, Ayleen. Pontificia Universidad Católica de Chile; ChileFil: Funes, Samanta Celeste. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Rios, Mariana. Pontificia Universidad Católica de Chile; ChileFil: Covián, Camila. Pontificia Universidad Católica de Chile; ChileFil: González, Jorge. Pontificia Universidad Católica de Chile; ChileFil: Kalergis, Alexis M.. Pontificia Universidad Católica de Chile; Chil

The Freundlich model of adsorption for calculation of specific surface areaS

The specific surface area of solids and the surface area occupied by the active phase (metal or oxide) on a support are parameters of the utmost importance in adsorption and catalysis. For the determination of the former, the BET equation is universally established. For the evaluation of the latter the works of selective chemisorption, initiated by Emmett and Brunauer (I ), for metals and by Bridges et al. (2) and Weller et al. (3), for oxides have come to represent important contributions. Some of the classical models of adsorption have also been used for evaluation of specific surfaces (Langmuir equation) (4) and the dispersion of supported metals or oxides (Freundlich equation) (5). Both of them are applicable to physisorption as well as chemisorption processes

Sustainable approach of high-pressure agave bagasse pretreatment for ethanol production

ABSTRACT: Agave bagasse is one of the most abundant lignocellulosic residues readily available for valorization. The agave bagasse was pretreated by applying high-pressure CO2–H2O mixture at temperatures ranging from 150 to 190 °C for a residence time varying from 10 to 50 min. Subsequently, solid phase obtained from pretreatment was subject to enzymatic hydrolysis at high solid loadings. Under optimal conditions, the process integrating pretreatment followed by enzymatic hydrolysis yielded 75.8 mol% of the polysaccharides present in the biomass converted into oligo- or monosaccharides, providing 110.5 g/L of reducing sugars. The monosaccharides present in the obtained hydrolysate were successfully fermented into ethanol, demonstrating the feasibility of performing its biological conversion to commercial biofuels or biochemicals. Thereby, the present study has demonstrated the proof of concept of use of more sustainable high-pressure CO2–H2O pretreatment in the context of lignocellulosic residual biomass valorization based on the biochemical sugar platform.info:eu-repo/semantics/publishedVersio

Influence of activation conditions on textural properties and performance of activated biochars for pyrolysis vapors upgrading

The main aim of the present study is to provide a comprehensive assessment of the effects of process activation conditions on the textural properties of the resulting activated carbons, which were produced from wheat straw-derived biochar through chemical activation (with K2CO3 at different pressures and mass impregnation ratios) and physical activation (with CO2 at different temperatures and pressures). For chemically activated biochars, it was found that specific surface area and pore size distribution were both only positively affected by increasing the carbonate loading. However, physically activated biochars produced at the highest pressure and lowest temperature (1.0 MPa and 700 °C) had the highest surface areas and widest pore size distributions. The materials with the most appropriate textural properties were then tested as catalysts for steam and dry reforming of the aqueous phase of pyrolysis oil. The best catalytic performance (a total gas yield of 74% and a selectivity toward H2 of almost 40%) was observed for a physically activated biochar. This good performance was ascribed to the high availability of K0 on the catalyst surface, which could effectively promote the reactions involved in the upgrading proces

Spatio-temporal variation in the composition of the macroalgae assemblage of the intertidal rocky zone from maitencillo, valparaíso, central coast of Chile

Indexación: Scopus.Records on the diversity of algae serve as a foundation for establishing management and environmental protection programs, as well as for determining new commercial uses of algae. With this context in mind, the goal of the present study was to determine the richness, coverage, and composition of the macroalgae assemblage in the intertidal zone of Maitencillo, Valparaíso, Chile over the course of 3 years (2013-2015). A total of 29 species were recorded from 3 phyla - 23 Rhodophyta; 3 Ochrophyta, of the Phaeophyceae class; and 3 Chlorophyta. Species richness presented high spatial and temporal variations, with these variations most significantly explained by intertidal zone (61%) and the seasons (31%). The highest levels of specific richness were recorded in the mid and lower intertidal zones (14 species) in spring, as well as in the lower intertidal zone (14 species) during summer. The lowest values of specific richness were recorded for the mid intertidal zone (2 species) during fall. The distinct levels of the intertidal zone also notably impacted algae assemblage, explaining 53% of variation while the seasons explained 18% of variation. The greatest coverage was recorded in the mid intertidal zone during spring, with a predominance of Mazzaella laminarioides and Ulva spp. complex. In turn, the lowest coverage was found in fall, linked with processes of sand accretion. In rocky walls, the Pyropia complex dominated. Results indicate a marked pattern of vertical and seasonal distribution in the macroalgae assemblage, as well as notably high presence of Rhodophyta species. This benthic flora description serves to update information on the diversity of representative algal species from Valparaíso Region of Chile. © 2018, Universidad de Valparaiso. All rights reserved