Optical transition probabilites and compositional dependence of Judd-Ofelt parameters of Er3+ ions in fluoroindate glass

Fluoroindate glasses containing 1, 2, 3, and 4 mol% ErF3 were prepared in a dry box under an argon atmosphere. Absorption spectra of these glasses at room temperature were obtained. The Judd-Ofelt parameters Omegalambda (lambda = 2, 4, 6) for f-f transitions of Er3+ ions as well as transition probabilities, branching ratios, radiative lifetimes, and peak cross-sections for stimulated emission of each band were determined. The concentration effect on the intensities is analyzed. The optical properties of the fluoroindate glasses doped with Er3+ ions are compared with those of other glasses described in the literature

Flue gas adsorption by single-wall carbon nanotubes: A Monte Carlo study

Adsorption of flue gases by single-wall carbon nanotubes (SWCNT) has been studied by means of Monte Carlo simulations. The flue gas is modeled as a ternary mixture of N2, CO2, and O2, emulating realistic compositions of the emissions from power plants. The adsorbed flue gas is in equilibrium with a bulk gas characterized by temperature T, pressure p, and mixture composition.We have considered different SWCNTs with different chiralities and diameters in a range between 7 and 20 Å. Our results show that the CO2 adsorption properties depend mainly on the bulk flue gas thermodynamic conditions and the SWCNT diameter. Narrow SWCNTs with diameter around 7 Å show high CO2 adsorption capacity and selectivity, but they decrease abruptly as the SWCNT diameter is increased. For wide SWCNT, CO2 adsorption capacity and selectivity, much smaller in value than for the narrow case, decrease mildly with the SWCNT diameter. In the intermediate range of SWCNT diameters, the CO2 adsorption properties may show a peculiar behavior, which depend strongly on the bulk flue gas conditions. Thus, for high bulk CO2 concentrations and low temperatures, the CO2 adsorption capacity remains high in a wide range of SWCNT diameters, although the corresponding selectivity is moderate.We correlate these findings with the microscopic structure of the adsorbed gas inside the SWCNTs.Peer reviewe

El humanismo cívico castellano: Alonso de Madrigal, Pedro de Osma y Fernando de Roa

El artículo aborda la tradición del «humanismo cívico» en el contexto de la escuela aristotélica de Salamanca, cuyos mejores representantes son El Tostado y sus discípulos Pedro de Osma y Fernando de Roa. El estudio de Cicerón, pero sobre todo de Aristóteles, resulta decisivo para comprender este republicanismo castellano iniciado en la segunda mitad del siglo XV. El artículo, a partir de la obra de los tres autores citados, analiza los principales tópicos del humanismo cívico

Horizontal gene transfer to a defensive symbiont with a reduced genome in a multipartite beetle microbiome

Symbiotic mutualisms of bacteria and animals are ubiquitous in nature, running a continuum from facultative to obligate from the perspectives of both partners. The loss of functions required for living independently but not within a host gives rise to reduced genomes in many symbionts. Although the phenomenon of genome reduction can be explained by existing evolutionary models, the initiation of the process is not well understood. Here, we describe the microbiome associated with the eggs of the beetle Lagria villosa, consisting of multiple bacterial symbionts related to Burkholderia gladioli, including a reduced-genome symbiont thought to be the exclusive producer of the defensive compound lagriamide. We show that the putative lagriamide-producing symbiont is the only member of the microbiome undergoing genome reduction and that it has already lost the majority of its primary metabolism and DNA repair pathways. The key step preceding genome reduction in the symbiont was likely the horizontal acquisition of the putative lagriamide lga biosynthetic gene cluster. Unexpectedly, we uncovered evidence of additional horizontal transfers to the symbiont's genome while genome reduction was occurring and despite a current lack of genes needed for homologous recombination. These gene gains may have given the genome-reduced symbiont a selective advantage in the microbiome, especially given the maintenance of the large lga gene cluster despite ongoing genome reduction. IMPORTANCE Associations between microorganisms and an animal, plant, or fungal host can result in increased dependence over time. This process is due partly to the bacterium not needing to produce nutrients that the host provides, leading to loss of genes that it would need to live independently and to a consequent reduction in genome size. It is often thought that genome reduction is aided by genetic isolation-bacteria that live in monocultures in special host organs, or inside host cells, have less access to other bacterial species from which they can obtain genes. Here, we describe exposure of a genome-reduced beetle symbiont to a community of related bacteria with nonreduced genomes. We show that the symbiont has acquired genes from other bacteria despite going through genome reduction, suggesting that isolation has not yet played a major role in this case of genome reduction, with horizontal gene gains still offering a potential route for adaptation

Spray-drying microencapsulation of tea extracts using green starch, alginate or carrageenan as carrier materials

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGTea industry generates many by-products which could be used to produce and incorporate bioactive tea extracts (TE) into nutraceuticals, cosmetics and/or clinical applications. However, sensibility to external factors is a major disadvantage hindering its utilization. This study deals with the implementation and characterization of suitable biopolymer delivery systems based on starch, carrageenan or alginate, as microencapsulation, to stabilize and protect TE through innovative thin-carbohydrate-coated formulations. TE were spray-dried and microencapsulated in recycled carrier materials (alginate, carrageenan or starch). Product yields varied from 55 to 58%. High microencapsulation and loading efficiencies were achieved (60–93% and 65–84%, respectively). Antioxidant capacity varied from 32 to 46 g Trolox/100 g extract, within different carrier-systems; which also showed promising rheological and UV-protective properties when transformed into gels. Total phenolic content, particle-size distribution, HPSEC-analysis, SEM-analysis and FTIR-analysis were also performed. In sum, this paper characterizes and discusses the high potential of these recycled carbohydrate-coated microparticles for future applicationsMinisterio de Ciencia, Innovación y Universidades | Ref. RYC2018-024454-IXunta de Galicia | Ref. ED431F 2020/01Xunta de Galicia | Ref. ED481B 2018/07