Search results for "ESA"
showing 10 items of 11914 documents
Phase stability and electronic structure of iridium metal at the megabar range
2019
[EN] The 5d transition metals have attracted specific interest for high-pressure studies due to their extraordinary stability and intriguing electronic properties. In particular, iridium metal has been proposed to exhibit a recently discovered pressure-induced electronic transition, the so-called core-level crossing transition at the lowest pressure among all the 5d transition metals. Here, we report an experimental structural characterization of iridium by x-ray probes sensitive to both long- and short-range order in matter. Synchrotron-based powder x-ray diffraction results highlight a large stability range (up to 1.4 Mbar) of the low-pressure phase. The compressibility behaviour was char…
Post-tilleyite, a dense calcium silicate-carbonate phase
2019
Scientific reports 9(1), 7898 (2019). doi:10.1038/s41598-019-44326-9
Out-of-plane orientation of luminescent excitons in two-dimensional indium selenide.
2019
Van der Waals materials offer a wide range of atomic layers with unique properties that can be easily combined to engineer novel electronic and photonic devices. A missing ingredient of the van der Waals platform is a two-dimensional crystal with naturally occurring out-of-plane luminescent dipole orientation. Here we measure the far-field photoluminescence intensity distribution of bulk InSe and two-dimensional InSe, WSe2 and MoSe2. We demonstrate, with the support of ab-initio calculations, that layered InSe flakes sustain luminescent excitons with an intrinsic out-of-plane orientation, in contrast with the in-plane orientation of dipoles we find in two-dimensional WSe2 and MoSe2 at room-…
Crack formation and cleaving of sapphire with ultrafast bessel beams
2017
Sapphire is a transparent crystalline dielectric of high hardness with many important applications, specifically to the next-generation touchscreens and to the LED growth, as substrates. However, sapphire cutting by ablative techniques is rather slow therefore fast material separation techniques are needed. Material separation by “stealth dicing” has been recently developed, it is based on material cleaving along a plane weakened by multiple ultrafast laser illuminations. This allows usually generating taper-free cutting and avoids material loss. However, the illuminated plane needs small spacing between the shot to shot (typically a few μm) and long damages inside the bulk. This requires l…
A Dirichlet Autoregressive Model for the Analysis of Microbiota Time-Series Data
2021
Growing interest in understanding microbiota dynamics has motivated the development of different strategies to model microbiota time series data. However, all of them must tackle the fact that the available data are high-dimensional, posing strong statistical and computational challenges. In order to address this challenge, we propose a Dirichlet autoregressive model with time-varying parameters, which can be directly adapted to explain the effect of groups of taxa, thus reducing the number of parameters estimated by maximum likelihood. A strategy has been implemented which speeds up this estimation. The usefulness of the proposed model is illustrated by application to a case study.
High-throughput sequencing (HTS) for the analysis of viral populations
2020
The development of High-Throughput Sequencing (HTS) technologies is having a major impact on the genomic analysis of viral populations. Current HTS platforms can capture nucleic acid variation across millions of genes for both selected amplicons and full viral genomes. HTS has already facilitated the discovery of new viruses, hinted new taxonomic classifications and provided a deeper and broader understanding of their diversity, population and genetic structure. Hence, HTS has already replaced standard Sanger sequencing in basic and applied research fields, but the next step is its implementation as a routine technology for the analysis of viruses in clinical settings. The most likely appli…
Stem Cell-Derived, microRNA-Carrying Extracellular Vesicles: A Novel Approach to Interfering with Mesangial Cell Collagen Production in a Hyperglycae…
2016
Extracellular vesicles (EVs) that are derived from stem cells are proving to be promising therapeutic options. We herein investigate the therapeutic potential of EVs that have been derived from different stem cell sources, bone-marrow (MSC) and human liver (HLSC), on mesangial cells (MCs) exposed to hyperglycaemia. By expressing a dominant negative STAT5 construct (ΔNSTAT5) in HG-cultured MCs, we have demonstrated that miR-21 expression is under the control of STAT5, which translates into Transforming Growth Factor beta (TGFβ) expression and collagen production. A number of approaches have been used to show that both MSC- and HLSC-derived EVs protect MCs from HG-induced damage via the trans…
Identifying Prognostic SNPs in Clinical Cohorts: Complementing Univariate Analyses by Resampling and Multivariable Modeling
2016
Clinical cohorts with time-to-event endpoints are increasingly characterized by measurements of a number of single nucleotide polymorphisms that is by a magnitude larger than the number of measurements typically considered at the gene level. At the same time, the size of clinical cohorts often is still limited, calling for novel analysis strategies for identifying potentially prognostic SNPs that can help to better characterize disease processes. We propose such a strategy, drawing on univariate testing ideas from epidemiological case-controls studies on the one hand, and multivariable regression techniques as developed for gene expression data on the other hand. In particular, we focus on …
Lipid levels, atrial fibrillation and the impact of age:Results from the LIPIDOGRAM2015 study
2020
Background and aims: An inverse relationship between lipid levels and atrial fibrillation (AF) has been suggested, but whether the association is upheld for all age groups remains unclear. The aim of the study was to examine associations between lipid levels and AF by age groups in a nationwide study in Poland. Methods: Multivariate Poisson regression models were used to estimate prevalence ratios (PRs) for AF by lipid levels. Low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), total cholesterol (TC), non-HDL-C and LDL-C/HDL-C ratios were grouped into quartiles. Results: Of the 13,724 participants, 5.2% (n = 708) had AF. People with…
Influencia del aceite de coco en enfermos de alzhéimer a nivel cognitivo.
2017
Resumen Introducción: la enfermedad de Alzheimer es a día de hoy la demencia neurodegenerativa con mayor prevalencia en el primer mundo. Este hecho, unido a la falta de tratamiento farmacológico que cure la enfermedad, hace que se estudien nuevas estrategias terapéuticas no farmacológicas como es la administración de nutrientes. En este sentido, destaca la posible influencia del aceite de coco como fuente energética alternativa, capaz de frenar la muerte neuronal que se produce de modo progresivo en esta enfermedad. Objetivos: valorar el impacto del aceite de coco a nivel cognitivo en pacientes de alzhéimer, y concretamente en las áreas de orientación, lenguaje-construcción, fijación, cálcu…