Morphology and structure of ABS membranes filled with two different activated carbons

Mixed matrix-composite membranes (MMCM) for gas separation are prepared and characterized in this work. Acrylonitrile-butadiene-styrene (ABS) copolymer was used for the continuum phase of the membrane filled with two different activated carbons (AC). The so-obtained membranes have been characterized by gas permeability, optical microscopy, electronic microscopy and atomic force microscopy. The membranes have different roughness on both their surfaces but are always recovered by the polymeric material. Better ABS-AC adhesion has been always reached giving high selectivity and permeability for CO2 / CH4. Such intimate contact can be attributed to the rubber properties of the butadiene-styrene chains in ABS. The morphological characteristics and the increase in both permeability and selectivity with the volume fraction of the filler are explained in terms of the properties of pure activated carbons.Fil: Marchese, Jose. Universidad Nacional de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Ciencias Fisico Matematicas y Naturales. Departamento de Fisica. Laboratorio de Ciencias de Superficies y Medios Porosos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis; ArgentinaFil: Anson, M.. Universidad Nacional de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Ciencias Fisico Matematicas y Naturales. Departamento de Fisica. Laboratorio de Ciencias de Superficies y Medios Porosos; ArgentinaFil: Ochoa, Nelio Ariel. Universidad Nacional de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Ciencias Fisico Matematicas y Naturales. Departamento de Fisica. Laboratorio de Ciencias de Superficies y Medios Porosos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis; ArgentinaFil: Prádanos, P.. Universidad de Valladolid; EspañaFil: Palacio, L.. Universidad de Valladolid; EspañaFil: Hernández, A.. Universidad de Valladolid; Españ

Effects of Silica Modification (Mg, Al, Ca, Ti, and Zr) on Supported Cobalt Catalysts for H₂-Dependent CO₂ Reduction to Metabolic Intermediates

Serpentinizing hydrothermal systems generate H2 as a reductant and harbor catalysts conducive to geochemical CO2 conversion into reduced carbon compounds that form the core of microbial autotrophic metabolism. This study characterizes mineral catalysts at hydrothermal vents by investigating the interactions between catalytically active cobalt sites and silica-based support materials on H2-dependent CO2 reduction. Heteroatom incorporated (Mg, Al, Ca, Ti, and Zr), ordered mesoporous silicas are applied as model support systems for the cobalt-based catalysts. It is demonstrated that all catalysts surveyed convert CO2 to methane, methanol, carbon monoxide, and low-molecular-weight hydrocarbons at 180 °C and 20 bar, but with different activity and selectivity depending on the support modification. The additional analysis of the condensed product phase reveals the formation of oxygenates such as formate and acetate, which are key intermediates in the ancient acetyl-coenzyme A pathway of carbon metabolism. The Ti-incorporated catalyst yielded the highest concentrations of formate (3.6 mM) and acetate (1.2 mM) in the liquid phase. Chemisorption experiments including H2 temperature-programmed reduction (TPR) and CO2 temperature-programmed desorption (TPD) in agreement with density functional theory (DFT) calculations of the adsorption energy of CO2 suggest metallic cobalt as the preferential adsorption site for CO2 compared to hardly reducible cobalt–metal oxide interface species. The ratios of the respective cobalt species vary depending on the interaction strength with the support materials. The findings reveal robust and biologically relevant catalytic activities of silica-based transition metal minerals in H2-rich CO2 fixation, in line with the idea that autotrophic metabolism emerged at hydrothermal vents

Tunable injectable alginate-based hydrogel for cell therapy in Type 1 Diabetes Mellitus

Islet transplantation has the potential of reestablishing naturally-regulated insulin production in Type 1 diabetic patients. Nevertheless, this procedure is limited due to the low islet survival after transplantation and the lifelong immunosuppression to avoid rejection. Islet embedding within a biocompatible matrix provides mechanical protection and a physical barrier against the immune system thus, increasing islet survival. Alginate is the preferred biomaterial used for embedding insulin-producing cells because of its biocompatibility, low toxicity and ease of gelation. However, alginate gelation is poorly controlled, affecting its physicochemical properties as an injectable biomaterial. Including different concentrations of the phosphate salt Na2HPO4 in alginate hydrogels, we can modulate their gelation time, tuning their physicochemical properties like stiffness and porosity while maintaining an appropriate injectability. Moreover, these hydrogels showed good biocompatibility when embedding a rat insulinoma cell line, especially at low Na2HPO4 concentrations, indicating that these hydrogels have potential as injectable biomaterials for Type 1 Diabetes Mellitus treatment

Agua para el desarrollo regional en los Altos de Jalisco. Gestión del agua e impacto social del proyecto El Zapotillo.

Este trabajo es resultado de una investigación dedicada al análisis de impactos sociales relacionados con la gestión del agua (subterránea y superficial) en Los Altos de Jalisco. Esta es una región de alta productividad pecuaria, donde se desarrolla el proyecto hidráulico El Zapotillo, una iniciativa gubernamental con participación privada que ha generado una importante polémica en el contexto estatal, nacional e internacional. El debate gira entorno a la distribución de aguas superficiales, el equilibrio de los acuíferos, el cambio climático y la importancia que tiene el agua en los medios de vida de la población que sería directa e indirectamente afectada por la presa, el trasvase y por la reserva de volúmenes de aguas disponibles. Este trabajo busca aportar a la reflexión sobre la gestión regional del agua en Jalisco y pretende detonar inquietudes que abonen a buscar, identificar y construir alternativas más sustentables que atiendan de manera integral los retos y la urgente necesidad de agua que tienen tanto el campo como la ciudades.Asociación Ganadera Local de San Juan de Los Lagos, Jalisc

Analysis of the Relationship between Lifestyle and Coffee Consumption Habits, from the Myth Approach, in the Municipalities of Orizaba, Tehuipango, and Zongolica Veracruz.

Coffee consumption habits have evolved along with society for more than 300 years around the world. Social changes imply different lifestyles in each culture. Lifestyles influence the myths used by people in their consumption decisions. The objective of this research is to determine the relationship between lifestyle and coffee consumption habits, from the perspective of myth, in the inhabitants of the Mexican municipalities of Orizaba, Tehuipango, and Zongolica. A survey was conducted with a sample of inhabitants of the three municipalities studied. The statistical analyzes applied were the central limit theorem, Pearson, and Chi-square. The results show that the variables Consumption habits-Lifestyle-Myth, are highly dependent on the level of perception of people. It is concluded that the coffee myth corresponds to the "family union" in the study municipalities. This myth is not characterized in the evolutionary stages contemplated in the "waves of coffee"

Flujo vaginal. Experiencia con el diagnóstico microbiológico de 1178 casos

During the year 1985 we studied 1178 adult women, from the laboratory viewpoint, in order to define the. etiology of their vaginal discharge; in 25,3% we established the diagnosis of bacterial vaginosis (Gardnerella vaginalis associated vaginitis); in 13,9% we found candidiasis and in 2,9% trichomoniasis; the remaining 54,2% did not fit any of these categories; three patients revealed either Geotrichurn or Trichosporon the significance of which in the vagina is unknown and should be further studied.En 1985 estudiamos, desde el punto de vista del laboratorio, 1178 mujeres adultas para definir la etiología de su flujo vaginal; se diagnosticó vaginosis bacteriana (vaginitis asociada a Gardnerella vaginalis) en 25.3% de los casos, candidiasis en 13,9% y Tricomoniasis en 2.9% en tres pacientes había levaduras de los géneros Geotrichum o Trichosporon cuyo significado en la vagina es desconocido y amerita ser estudiado

Functional traits determine plant co-occurrence more than environment or evolutionary relatedness in global drylands

Plant–plant interactions are driven by environmental conditions, evolutionary relationships (ER) and the functional traits of the plants involved. However, studies addressing the relative importance of these drivers are rare, but crucial to improve our predictions of the effects of plant–plant interactions on plant communities and of how they respond to differing environmental conditions. To analyze the relative importance of – and interrelationships among – these factors as drivers of plant–plant interactions, we analyzed perennial plant co-occurrence at 106 dryland plant communities established across rainfall gradients in nine countries. We used structural equation modelling to disentangle the relationships between environmental conditions (aridity and soil fertility), functional traits extracted from the literature, and ER, and to assess their relative importance as drivers of the 929 pairwise plant–plant co-occurrence levels measured. Functional traits, specifically facilitated plants’ height and nurse growth form, were of primary importance, and modulated the effect of the environment and ER on plant–plant interactions. Environmental conditions and ER were important mainly for those interactions involving woody and graminoid nurses, respectively. The relative importance of different plant–plant interaction drivers (ER, functional traits, and the environment) varied depending on the region considered, illustrating the difficulty of predicting the outcome of plant–plant interactions at broader spatial scales. In our global-scale study on drylands, plant–plant interactions were more strongly related to functional traits of the species involved than to the environmental variables considered. Thus, moving to a trait-based facilitation/competition approach help to predict that: (1) positive plant–plant interactions are more likely to occur for taller facilitated species in drylands, and (2) plant–plant interactions within woody-dominated ecosystems might be more sensitive to changing environmental conditions than those within grasslands. By providing insights on which species are likely to better perform beneath a given neighbour, our results will also help to succeed in restoration practices involving the use of nurse plants

Large deep-sea zooplankton biomass mirrors primary production in the global ocean

The biological pump transports organic carbon produced by photosynthesis to the meso- and bathypelagic zones, the latter removing carbon from exchanging with the atmosphere over centennial time scales. Organisms living in both zones are supported by a passive flux of particles, and carbon transported to the deep-sea through vertical zooplankton migrations. Here we report globally-coherent positive relationships between zooplankton biomass in the epi-, meso-, and bathypelagic layers and average net primary production (NPP). We do so based on a global assessment of available deep-sea zooplankton biomass data and large-scale estimates of average NPP. The relationships obtained imply that increased NPP leads to enhanced transference of organic carbon to the deep ocean. Estimated remineralization from respiration rates by deep-sea zooplankton requires a minimum supply of 0.44 Pg C y(-1) transported into the bathypelagic ocean, comparable to the passive carbon sequestration. We suggest that the global coupling between NPP and bathypelagic zooplankton biomass must be also supported by an active transport mechanism associated to vertical zooplankton migration