110 research outputs found
Microsecond time-resolved X-ray diffraction for the investigation of fatigue behavior during ultrasonic fatigue loading
International audienceA new method based on time-resolved X-ray diffraction is proposed in order to measure the elastic strain and stress during ultrasonic fatigue loading experiments. Pure Cu was chosen as an example material for the experiments using a 20 kHz ultrasonic fatigue machine mounted on the six-circle diffractometer available at the DiffAbs beamline on the SOLEIL synchrotron facility in France. A two-dimensional hybrid pixel X-ray detector (XPAD3.2) was triggered by the strain gage signal in a synchronous data acquisition scheme (pump–probe-like). The method enables studying loading cycles with a period of 50 µs, achieving a temporal resolution of 1 µs. This allows a precise reconstruction of the diffraction patterns during the loading cycles. From the diffraction patterns, the position of the peaks, their shifts and their respective broadening can be deduced. The diffraction peak shift allows the elastic lattice strain to be estimated with a resolution of ∼10−5. Stress is calculated by the self-consistent scale-transition model through which the elastic response of the material is estimated. The amplitudes of the cyclic stresses range from 40 to 120 MPa and vary linearly with respect to the displacement applied by the ultrasonic machine. Moreover, the experimental results highlight an increase of the diffraction peak broadening with the number of applied cycles
Distinct mechanisms regulate Cdx2 expression in the blastocyst and in trophoblast stem cells
The first intercellular differences during mammalian embryogenesis arise in the blastocyst, producing the inner cell mass and the trophectoderm. The trophectoderm is the first extraembryonic tissue and does not contribute to the embryo proper, its differentiation instead forming tissues that sustain embryonic development. Crucial roles in extraembryonic differentiation have been identified for certain transcription factors, but a comprehensive picture of the regulation of this early specification is still lacking. Here, we investigated whether the regulatory mechanisms involved in Cdx2 expression in the blastocyst are also utilized in the postimplantation embryo. We analyzed an enhancer that is regulated through Hippo and Notch in the blastocyst trophectoderm, unexpectedly finding that it is inactive in the extraembryonic structures at postimplantation stages. Further analysis identified other Cdx2 regulatory elements including a stem-cell specific regulatory sequence and an element that drives reporter expression in the trophectoderm, a subset of cells in the extraembryonic region of the postimplantation embryo and in trophoblast stem cells. The cross-comparison in this study of cis-regulatory elements employed in the blastocyst, stem cell populations and the postimplantation embryo provides new insights into early mammalian development and suggests a two-step mechanism in Cdx2 regulation.We thank Barbara Pernaute for comments and suggestions; members of the Manzanares lab for comments, technical help and support; Ian Chambers and Austin Smith for the ZHBTc4 ES cell line; Tristan Rodriguez for the B1-TS cell line; Luis Miguel Criado and the CNIC Transgenesis Unit for TS cell morulae injections and support; Roisin Doohan for help with sections; and Simon Bartlett (CNIC) for English editing. This study was funded by grants from the Ministerio de Economia y Competitividad (grant BFU2011-23083 and BFU2014-54608-P to MM; FPU Doctoral Fellowship to TR; FPI-SO Doctoral Fellowship to SM; Severo Ochoa Center of Excellence award SEV-2015-0505 to CNIC), Comunidad Autonoma de Madrid (grant CELLDD-CM to MM), Canadian Institute of Health Research (JR), Imperial College (VA), and the MRC and Genesis Research Trust (AH). The CNIC is supported by the Spanish Ministerio de Economia y Competitividad and the Pro-CNIC Foundation.S
Algoritmo de Sincronización del Electrocardiograma Para Análisis Retrospectivos Basados en Vectocardiograma
El Vectocardiograma (VCG) ofrece una representación
tridimensional completa de la actividad eléctrica del corazón, lo
que resulta de gran valor para el diagnóstico y tratamiento de
afecciones cardiovasculares. El registro del VCG no se
adquiere de manera común, pero puede reconstruirse a partir
del electrocardiograma (ECG) a partir de transformaciones
lineales. El formato de ECG clásico en papel o pdf registra doce
derivaciones de manera intermitente cada 2.5 segundos y la
derivación continua comúnmente la II. Esto supone un desafío
para reconstruir el VCG, ya que los latidos en cada derivación
ocurren en momentos temporales distintos.
El objetivo de esta investigación es proponer una metodología
que permita sincronizar con precisión los latidos registrados
para reconstruir el VCG y validarlo con un gran número de
señales.
Los resultados demuestran una sincronización precisa,
evidenciada por los valores de correlación de Pearson de
0,9840 ± 0,0397, un error absoluto medio (MAE) de 0,0133 ±
0,0123 mV y una raíz del error cuadrático medio (RMSE) de
0,0248 ± 0,0214 mV en la reconstrucción del VCG.
El método de sincronización propuesto permitirá la realización
de estudios retrospectivos a partir del VCG en los que
únicamente se dispone de registros convencionales de ECGEste trabajo ha sido parcialmente subvencionado por el
PID2019-109547RB-I00 (Programa Nacional de
Investigación, Ministerio de Ciencia e Innovación,
Gobierno de España) y el PID2022-142514OB-100
CIBERCV CB16/11/00486 (Instituto de Salud Carlos III)
Impact of using eHealth tools to extend health services to rural areas of Nigeria: protocol for a mixed-method, non-randomised cluster trial
Introduction: eHealth solutions that use internet and related technologies to deliver and enhance health services and information are emerging as novel approaches to support healthcare delivery in sub-Saharan Africa. Using digital technology in this way can support cost-effectiveness of care delivery and extend the reach of services to remote locations. Despite the burgeoning literature on eHealth approaches, little is known about the effectiveness of eHealth tools for improving the quality and efficiency of health systems functions or client outcomes in resource-limited countries. eHealth tools including satellite communications are currently being implemented at scale, to extend health services to rural areas of Nigeria, in Ondo and Kano States and the Federal Capital Territory. This paper shares the protocol for a 2-year project (‘EXTEND’) that aims to evaluate the impact of eHealth tools on health system functions and health outcomes.
Methodology and analysis: This multisite, mixed-method evaluation includes a non-randomised, cluster trial design. The study comprises three phases—baseline, midline and endline evaluations—that involve: (1) process evaluation of video training and digitisation of health data interventions; (2) evaluation of contextual influences on the implementation of interventions; and (3) impact evaluation of results of the project. A convergent mixed-method model will be adopted to allow integration of quantitative and qualitative findings to achieve study objectives. Multiple quantitative and qualitative datasets will be repeatedly analysed and triangulated to facilitate better understanding of impact of eHealth tools on health worker knowledge, quality and efficiency of health systems and client outcomes.
Ethics and dissemination: Ethics approvals were obtained from the University of Leeds and three States’ Ministries of Health in Nigeria. All data collected for this study will be anonymised and reports will not contain information that could identify respondents. Study findings will be presented to Ministries of Health at scientific conferences and published in peer-reviewed journals.
Trial registration number: ISRCTN32105372; Pre-results
Air and water pollution over time and industries with stochastic dominance
We employ a stochastic dominance (SD) approach to analyze the components that contribute to environmental degradation over time. The variables include countries\u2019 greenhouse gas (GHG) emissions and water pollution. Our approach is based on pair-wise SD tests. First, we study the dynamic progress of each separate variable over time, from 1990 to 2005, within 5-year horizons. Then, pair-wise SD tests are used to study the major industry contributors to the overall GHG emissions and water pollution at any given time, to uncover the industry which contributes the most to total emissions and water pollution. While CO2 emissions increased in the first order SD sense over 15 years, water pollution increased in a second-order SD sense. Electricity and heat production were the major contributors to the CO2 emissions, while the food industry gradually became the major water polluting
industry over time.
SD sense over 15 years, water pollution increased in
a second-order SD sense. Electricity and heat production
were the major contributors to the CO2 emissions, while
the food industry gradually
Incorporating field wind data to improve crop evapotranspiration parameterization in heterogeneous regions
Accurate parameterization of reference evapotranspiration ( ET0) is necessary for optimizing irrigation scheduling and avoiding costs associated with over-irrigation (water expense, loss of water productivity, energy costs, and pollution) or with under-irrigation (crop stress and suboptimal yields or quality). ET0 is often estimated using the FAO-56 method with meteorological data gathered over a reference surface, usually short grass. However, the density of suitable ET0 stations is often low relative to the microclimatic variability of many arid and semi-arid regions, leading to a potentially inaccurate ET0 for irrigation scheduling. In this study, we investigated multiple ET0 products from six meteorological stations, a satellite ET0 product, and integration (merger) of two stations’ data in Southern California, USA. We evaluated ET0 against lysimetric ET observations from two lysimeter systems (weighing and volumetric) and two crops (wine grapes and Jerusalem artichoke) by calculating crop ET ( ETc) using crop coefficients for the lysimetric crops with the different ET0. ETc calculated with ET0 products that incorporated field-specific wind speed had closer agreement with lysimetric ET, with RMSE reduced by 36 and 45% for grape and Jerusalem artichoke, respectively, with on-field anemometer data compared to wind data from the nearest station. The results indicate the potential importance of on-site meteorological sensors for ET0 parameterization; particularly where microclimates are highly variable and/or irrigation water is expensive or scarce
Conserved genes and pathways in primary human fibroblast strains undergoing replicative and radiation induced senescence
Additional file 3: Figure S3. Regulation of genes of Arrhythmogenic right ventricular cardiomyopathy pathway during senescence induction in HFF strains Genes of the “Arrhythmogenic right ventricular cardiomyopathy” pathway which are significantly up- (green) and down- (red) regulated (log2 fold change >1) during irradiation induced senescence (120 h after 20 Gy irradiation) in HFF strains. Orange color signifies genes which are commonly up-regulated during both, irradiation induced and replicative senescence
- …