Inducible model for β-six-mediated site-specific recombination in mammalian cells

The prokaryotic β recombinase catalyzes site-specific recombination between two directly oriented minimal six sites in chromatin-integrated substrates. Here, we demonstrate that an enhanced green fluorescent protein (EGFP)-fused version of β recombinase (β-EGFP) is fully active, retaining most specific activity. It is used to develop a recombination-dependent activatable gene expression (RAGE) system based on the androgen receptor (AR) ligand-binding domain (LBD). Two hybrid molecules, a direct fusion of the LBD-AR to the C-terminus of β recombinase (β-AR) and a triple fusion of β-EGFP to the same ligand-binding domain (β-EGFP-AR), were engineered and their subcellular behavior, stability and catalytic activity were evaluated. Both chimeric β recombinase proteins showed in vivo inducible recombinogenic activity dependent on addition of an androgen receptor agonist, although the β-AR fusion protein demonstrated more accurate ligand-dependent translocation from cytoplasm to nucleus

Pre-notched dog bone small punch specimens for the estimation of fracture properties

In recent years, the pre-notched or pre-cracked small punch test (P-SPT) has been successfully used to estimate the fracture properties of metallic materials for cases in which there is not sufficient material to identify these properties from standard tests, such as CT or SENB specimens. The P-SPT basically consists of deforming a pre-notched miniature specimen, whose edges are firmly gripped by a die, using a high strength punch. The novelty of this paper lies in the estimation of fracture properties using dog-bone-shaped specimens with different confinement levels. With these specimens, three confinement variations have been studied. The results obtained enable the establishment of a variation of fracture properties depending on the level of confinement of each miniature specimen and selection of the most appropriate confinement for this goal.Ministry of Economy and Competitiveness of Spain through grant MAT2014-58738-C

PVDF/BaTiO3/carbon nanotubes ternary nanocomposites prepared by ball milling: Piezo and dielectric responses

Nanocomposites based on poly(vinylidene fluoride) (PVDF) filled with barium titanate, BaTiO3, (BT) particles, and multiwalled carbon nanotubes (MWCNTs) were prepared by high-energy ball milling (HEBM) and subsequent hot pressing. This method of materials preparation allowed obtaining uniform dispersions of the nanofillers. The influence of the particles on the polymer structure and morphology was studied. To understand the origin of changes in the PVDF properties, thermal and electrical behaviors of the PVDF/BT/MWCNT nanocomposites were studied as a function of composition. The addition of BT, MWCNT, or its mixture had not any influence on the PVDF polymorphism. However, calorimetric results pointed out that the presence of the nanofillers exerted nucleation mainly ascribed to the surface to volume ratio of the nanoparticles. The capacitance of the composites increased as the nanofiller content increased, being the effect mainly dependent on the surface to volume ratio of the nanoparticles. The dielectric behavior of the materials as a function of frequency was modeled by a Debye equivalent circuit only below the percolation threshold respect to the amount of MWCNT. The piezoelectric behavior of the ternary nanocomposites was highly affected by the incorporation of the nanofillers only when high dielectric losses occurred above the percolation threshold.The authors gratefully acknowledge the financial support from the Ministerio de Ciencia e Innovacion (MAT2010-16815) and the Ministerio de Asuntos Exteriores y de Cooperacion and the Agencia Espanola de Cooperacion Internacional para el Desarrollo for supporting the Ph.D. thesis of F.A.S

Reinforced silica-carbon nanotube monolithic aerogels synthesised by rapid controlled gelation

This work introduces a new synthesis procedure for obtaining homogeneous silica hybrid aerogels with carbon nanotube contents up to 2.50 wt.%. The inclusion of nanotubes in the highly porous silica matrix was performed by a two-step sol–gel process, resulting in samples with densities below 80 mg/cm3. The structural analyses (N2 physisorption and SEM) revealed the hierarchical structure of the porous matrix formed by nanoparticles arranged in clusters of 100 and 300 nm in size, specific surface areas around 600 m2/g and porous volumes above 4.0 cm3/g. In addition, a relevant increase on the mechanical performance was found, and an increment of 50% for the compressive strength and 90% for the maximum deformation were measured by uniaxial compression. This reinforcement was possible thanks to the outstanding dispersion of the CNT within the silica matrix and the formation of Si–O–C bridges between nanotubes and silica matrix, as suggested by FTIR. Therefore, the original synthesis procedure introduced in this work allows the fabrication of highly porous hybrid materials loaded with carbon nanotubes homogeneously distributed in the space, which remain available for a variety of technological applications

Parameter Optimisation in Selective Laser Melting on C300 Steel

Additive manufacturing (AM) of metallic materials is increasingly being adopted in numerous sectors, such as biomedicine, aerospace or automotive industries, due to its versatility in the creation of complex geometries and the minimisation of material waste when compared to traditional subtractive methods. In order to ensure a reliable operation of these parts, however, an in-depth study of the effect of additive manufacturing on mechanical properties, including tensile, fatigue and fracture resistance, is necessary. Among the vast number of methods and materials, this project is focused in one of the most promising techniques for the industry: Selective Laser Melting (SLM) for the production of a tools steel, in particular C300 steel components for the automotive sector. The main objective of this paper is to optimise some of the key parameters in the printing process, such as laser power, laser speed and hatch spacing. These variables are essential to obtain parts with good resistance. To that purpose, tensile tests were performed in 3D printed specimens, and then elastoplastic properties were extracted, organised and analysed through a design of experiments for the subsequent output fitting using the response surface methodology.This research was funded by: INVESTUN/22/BU/0003 // BU-002-P20 // MU-21-UP2021-030

Critical Care Requirements Under Uncontrolled Transmission of SARS-CoV-2

Objectives. To estimate the critical care bed capacity that would be required to admit all critical COVID-19 cases in a setting of unchecked SARS-CoV-2 transmission, both with and without elderly-specific protection measures. Methods. Using electronic health records of all 2432 COVID-19 patients hospitalized in a large hospital in Madrid, Spain, between February 28 and April 23, 2020, we estimated the number of critical care beds needed to admit all critical care patients. To mimic a hypothetical intervention that halves SARS-CoV-2 infections among the elderly, we randomly excluded 50% of patients aged 65 years and older. Results. Critical care requirements peaked at 49 beds per 100 000 on April 1-2 weeks after the start of a national lockdown. After randomly excluding 50% of elderly patients, the estimated peak was 39 beds per 100 000. Conclusions. Under unchecked SARS-CoV-2 transmission, peak critical care requirements in Madrid were at least fivefold higher than prepandemic capacity. Under a hypothetical intervention that halves infections among the elderly, critical care peak requirements would have exceeded the prepandemic capacity of most high-income countries. Public Health Implications. Pandemic control strategies that rely exclusively on protecting the elderly are likely to overwhelm health care systems.S

Structural evolution of the El Salvador Fault Zone: an evolving fault system within a volcanic arc.

The El Salvador Fault Zone, firstly identifiedafter the 13th February 2001 Mw 6.6 El Salvador earthquake, is a 150 km long,20 km wide right-lateral strike-slip fault system. Ruptures along the ESFZ arethought to be responsible for most of the historical destructive earthquakesalong the El Salvador Volcanic Arc, as well as for most of the currentseismicity of the area. In this work, we focus on the geological setting of thefault zone by describing its geomorphology and structure, using field-based observations,digital terrain modelling, and aerial photograph interpretation with the aim atcontributing to the understanding of the ESFZ slip behaviour. In particular, weaddress the ESFZ structure, kinematics and evolution with time. The ESFZ is a complex set of traces divided inmajor rupture segments characterized by different geometry, kinematics andgeomorphic expressions. Natural fault exposures and paleoseismic trenchesexcavated along the fault show that the strike slip deformation is distributedin several planes. Both geometry and kinematics of the fault zone areconsistent with a transtensional strain regime.The estimated geological slip-rate for the mainfault segments by paleoseismic trenches and displaced geomorphic features impliesa deficit in velocity of the fault compared to the available GPS velocitiesdata. The high vertical scarps of some fault segments would require quaternaryslip rates not coherent neither with measured GPS velocities nor with sliprates obtained from paleoseismic analysis. This mismatch suggests apre-existing graben structure that would be inherited from the previousregional roll back related extensional stage. We consider that the ESFZ isusing this relict structure to grow up along it. As a result, we propose amodel for ESFZ development consistent with all these observations.La Zona de Falla de El Salvador (ZFES) es un sistema de falla de desgarre dextral de 150 km de longitud y 20 de anchura, que fue identificada por primera vez después del terremoto de Mw 6.6 de El Salvador de febrero de 2001. La mayoría de la sismicidad y de los terremotos históricos destructivos producidos en el arco volcánico salvadoreño han sido producidos por la ruptura de la ZFES. Este trabajo se centra en el marco geológico de la zona de falla describiendo su geomorfología y su estructura a través de observaciones de campo, del estudio de los modelos digitales del terreno y de la interpretación de las fotografías aéreas, con el objetivo de avanzar en el conocimiento del comportamiento de la ZFES. En concreto trataremos del estudio de la estructura, la cinemática y la evolución de la ZFES. La ZFES es un complejo sistema de fallas divididas en varios segmentos que se diferencian en la geometría, la cinemática y la expresión geomorfológica. En los afloramientos de la falla, así como en las trincheras paleosismicas excavadas se ha observado que la deformación de desgarre está distribuida en varios planos y tanto la geometría como la cinemática de la zona de falla indican que la ZFES está bajo un régimen de deformación transtensional. La tasa de deformación estimada para los principales segmentos a través del estudio paleosísmico y del análisis de indicadores geomorfológicos desplazados nos muestra un déficit de velocidad para la falla si lo comparamos con los datos obtenidos por GPS. Estos datos tampoco ayudan a explicar la existencia de grandes escarpes verticales que se observan en algunos segmentos de la falla, y que requerirían tasas de deformación muy elevadas. Esta discrepancia sugiere la existencia de una estructura de graben preexistente que puedo ser producida por el “roll-back” de la placa y que creó una fase extensional en el arco volcánico. En este trabajo consideramos que la ZFES está actualmente desarrollándose sobre la estructura extensional relicta y como resultado proponemos un modelo estructural consistente con estas observaciones

Subindividual variation accounts for most of the variability in two reproductive traits in Cistus ladanifer

There is increasing evidence of within species flower trait variability. In Cistus ladanifer, there is a great variation in the number of locules of the ovary (6–12). In this study, we assessed the variation in the number of ovary locules and ovule production at population, individual and intraindividual levels in 5 localities in the Madrid Region (Central Spain). We have answered the following questions: What level present larger variation? Is there a relationship between the number of ovary locules and ovule production? And if yes, does it hold across all levels? We sampled almost 500 flowers from 50 individuals for five localities. We counted the number of locules of the ovary and estimate the number of ovules per flower. The partitioning of total variation among populations, individuals and within-individuals was estimated for both variables. To analyze differences among locations, we performed general linear models. We found that within-individual variation was the main source of variation for all measured variables. Inter-individual variation was relevant only for the number of locules, and interpopulation variation was almost negligible for all variables. Despite the positive correlation between the number of locules per flower and ovule production, populations with more locules did not present more ovules per flower. In summary, we found that variation in the number of locules and its relationship with ovule production is scale dependent

Auge y colapso de la demanda de viviendas en España : factores determinantes

En este artículo se presenta un modelo de demanda de viviendas que permite analizar las causas que motivaron el boom inmobiliario protagonizado por la economía española, así como su posterior colapso. Según nuestro modelo, el boom tuvo su origen en el alza especulativa de precios, que produjo un doble efecto. Por un lado, el aumento de la riqueza inmobiliaria incrementó la capacidad financiera familiar, induciendo una mayor propensión al endeudamiento y a la inversión residencial. Por otro, el hecho de que la revalorización de la vivienda superara por momentos la cuota hipotecaria indujo un incremento adicional de la demanda de aquéllas. Sin embargo, estas fuerzas comenzaron a jugar en sentido contrario tras la explosión de la burbuja, provocando un brusco desplome de las compraventas. El modelo pone de relieve que la secular preferencia de los españoles por la vivienda en propiedad tenía un fundamento económico que ahora ha desaparecidoThis article presents a model for the demand for housing which allows one to analyze the determinants of the housing boom and bust experienced by the Spanish economy. According to this model, the boom was caused by a speculative increase in prices, which yielded two effects: on the one hand, the rise in wealth associated with the value of real estate increased households’ financial capacity, leading to a higher propensity to engage in debt and to invest in real estate. On the other hand, the fact that the appreciation in the value of housing was larger at certain times than the value of the mortgage to be paid, led to an even larger increase in the demand for housing. However, these forces began to act in the opposite direction after the bust of the housing bubble, causing an abrupt reduction in the demand for real estate. The model shows that the long term preference of Spaniards for house ownership rested on economic foundations which have now disappeare