108 research outputs found

    On the application of Jacobian-free Riemann solvers for relativistic radiation magnetohydrodynamics under M1 closure

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    Radiative transfer plays a major role in high-energy astrophysics. In multiple scenarios and in a broad range of energy scales, the coupling between matter and radiation is essential to understand the interplay between theory, observations and numerical simulations. In this paper, we present a novel scheme for solving the equations of radiation relativistic magnetohydrodynamics within the parallel code L\'ostrego. These equations, which are formulated taking successive moments of the Boltzmann radiative transfer equation, are solved under the gray-body approximation and the M1 closure using an IMEX time integration scheme. The main novelty of our scheme is that we introduce for the first time in the context of radiation magnetohydrodynamics a family of Jacobian-free Riemann solvers based on internal approximations to the Polynomial Viscosity Matrix, which were demonstrated to be robust and accurate for non-radiative applications. The robustness and the limitations of the new algorithms are tested by solving a collection of one-dimensional and multi-dimensional test problems, both in the free-streaming and in the diffusion radiation transport limits. Due to its stable performance, the applicability of the scheme presented in this paper to real astrophysical scenarios in high-energy astrophysics is promising. In future simulations, we expect to be able to explore the dynamical relevance of photon-matter interactions in the context of relativistic jets and accretion discs, from microquasars and AGN to gamma-ray bursts.Comment: 21 pages, 13 figures. Accepted for publication in Computer Physics Communication

    Variación de la temperatura en las capas externas del cuerpo humano irradiado a alta frecuencia (HF)

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    The absorption of energy by human external tissue when HF irradiation and the physical consequences involved are the purposes of this study. When it is directed toward the surface of the skin, energy is transmitted to its inner layers causing an increase of the temperature. This process has experimentally been proved to be beneficial in many cases. Yet theoretically there is still a slightly hollow basis about it. Skin tissue is actually a multilayer tissue with a different characteristic in each layer. Each one of them is characterized by some parameters, such as permittivity, conductivity, density and specific heat. Two kinds of skin tissues will be analyzed: a fibrous and a fatty one, each of both with a different skin humidity. Our model takes into account the heating by HF radiation, the redistribution of energy through the tissues and the cooling rate by blood in order to predict the increasing of tissue temperature in differents situations.Ingeniería, Industria y Construcció

    Transferencia de calor mediante la aplicación de RF sobre un modelo multicapa de tejido dérmico

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    HF radiation applied on the surface of the skin by an electrode is absorbed and it causes interior changes that redound into a smoother skin with less wrinkles. In this study, it is exposed a multiplayer method to determine absorbed radiation and increasing of temperature for each internal tissue. Each tissue is represented by a layer with certain parameters, such as permittivity, conductivity, density and specific heat. The model is applied to two different distributions of tissues: a fibrous and a fatty one. It is found that a fibrous distribution absorbs more energy than a fatty one, and also how the absorption could even be increased by previous humidification.Ingeniería, Industria y Construcció

    Controlled degradability of PCL-ZnO nanofibrous scaffolds for bone tissue engineering and their antibacterial activity

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    Up to date, tissue regeneration of large bone defects is a clinical challenge under exhaustive study. Nowadays, the most common clinical solutions concerning bone regeneration involve systems based on human or bovine tissues, which suffer from drawbacks like antigenicity, complex processing, low osteoinductivity, rapid resorption and minimal acceleration of tissue regeneration. This work thus addresses the development of nanofibrous synthetic scaffolds of polycaprolactone (PCL) - a long-term degradation polyester - compounded with hydroxyapatite (HA) and variable concentrations of ZnO as alternative solutions for accelerated bone tissue regeneration in applications requiring mid- and long-term resorption. In vitro cell response of human fetal osteoblasts as well as antibacterial activity against Staphylococcus aureus of PCL:HA:ZnO and PCL:ZnO scaffolds were here evaluated. Furthermore, the effect of ZnO nanostructures at different concentrations on in vitro degradation of PCL electrospun scaffolds was analyzed. The results proved that higher concentrations ZnO may induce early mineralization, as indicated by high alkaline phosphatase activity levels, cell proliferation assays and positive Alizarin-Red-S-stained calcium deposits. Moreover, all PCL:ZnO scaffolds particularly showed antibacterial activity against S. aureus which may be attributed to release of Zn2+ ions. Additionally, results here obtained showed a variable PCL degradation rate as a function of ZnO concentration. Therefore, this work suggests that our PCL:ZnO scaffolds may be promising and competitive short-, mid- and long-term resorption systems against current clinical solutions for bone tissue regeneration.Fil: Felice, Betiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología; ArgentinaFil: Sanchez, Maria Alejandra. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Socci, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología; ArgentinaFil: Sappia, Luciano David. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Gómez, María Inés. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química Inorgánica; ArgentinaFil: Cruz, María Karina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química Inorgánica; ArgentinaFil: Felice, Carmelo Jose. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Martí, Mercè. Universitat Autònoma de Barcelona; EspañaFil: Pividori, María Isabel. Universitat Autònoma de Barcelona; EspañaFil: Simonelli, Gabriela. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; ArgentinaFil: Rodriguez, Andrea Paola. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentin

    Oxidative Stress, Neuroinflammation and Mitochondria in the Pathophysiology of Amyotrophic Lateral Sclerosis

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    Amyotrophic lateral sclerosis (ALS) is a progressive motor neuron (MN) disease. Its primary cause remains elusive, although a combination of different causal factors cannot be ruled out. There is no cure, and prognosis is poor. Most patients with ALS die due to disease-related complications, such as respiratory failure, within three years of diagnosis. While the underlying mechanisms are unclear, different cell types (microglia, astrocytes, macrophages and T cell subsets) appear to play key roles in the pathophysiology of the disease. Neuroinflammation and oxidative stress pave the way leading to neurodegeneration and MN death. ALS-associated mitochondrial dysfunction occurs at different levels, and these organelles are involved in the mechanism of MN death. Molecular and cellular interactions are presented here as a sequential cascade of events. Based on our present knowledge, the discussion leads to the idea that feasible therapeutic strategies should focus in interfering with the pathophysiology of the disease at different steps

    Stress compensation by gap monolayers for stacked InAs/GaAs quantum dots solar cells

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    In this work we report the stacking of 10 and 50 InAs quantum dots layers using 2 monolayers of GaP for stress compensation and a stack period of 18 nm on GaAs (001) substrates. Very good structural and optical quality is found in both samples. Vertical alignment of the dots is observed by transmission electron microscopy suggesting the existence of residual stress around them. Photocurrent measurements show light absorption up to 1.2 μm in the nanostructures together with a reduction in the blue response of the device. As a result of the phosphorus incorporation in the barriers, a very high thermal activation energy (431 meV) has also been obtained for the quantum dot emission

    Sulfuric acid recovery from acid mine drainage by means of electrodialysis

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    In the present work the recovery of sulfuric acid from acid mine drainage by means of 3-compartment electrodialysis (ED) is evaluated. An effective recovery of sulfuric acid free from Fe(III) species was obtained in the anodic compartment as a result of the co-ion exclusion mechanism in the membranes. The difference in the pH and pSO42 − values between the membrane phase and the external electrolyte promotes the dissociation of complex species inside the membranes. This phenomenon impedes the transport of Fe(III) and sulfates in the form of complex ions toward the anodic and cathodic compartment, respectively. The current efficiency values of the anion-exchange membrane at different current densities were approximately constant with time. However, the increase in the recovery of acid decreases as the current increases. This result is explained by the shift in the equilibrium at the membrane/solution interface as more SO42 − ions cross the anionic membrane and, by the enhancement of the dissociation of water when the limiting current density is exceeded. The main limitation of the process is related to an abrupt increase in the cell voltage due to the formation of precipitates at the surface of the cation-exchange membrane.This work was supported by Ministerio de Economia y Competitividad (Spain) with the project number CTQ2012-37450-C02-01/PPQ. M.C. Marti-Calatayud is grateful to the Universitat Politecnica de Valencia for a postgraduate grant (Ref.: 2010-12). D.C. Buzzi wants to express her gratitude to CAPES (Brazil) for a postgraduate grant (Proc. BEX 8747/11-3).Martí Calatayud, MC.; Cardoso Buzzi, D.; García Gabaldón, M.; Ortega Navarro, EM.; Bernardes, A.; Suarez Tenorio, JA.; Pérez Herranz, V. (2014). Sulfuric acid recovery from acid mine drainage by means of electrodialysis. Desalination. 343:120-127. https://doi.org/10.1016/j.desal.2013.11.03112012734

    High-Intensity Interval Training (HIIT) on Biological and Body Composition Variables in Patients with Musculoskeletal Disorders: A Systematic Review and Meta-Analysis

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    In order to assess the impact of high-intensity interval training (HIIT) on biological and body composition variables in patients with musculoskeletal disorders (MSKD), a systematic search on PubMed (Medline), CENTRAL, CINAHL, Web of Science, SPORTDiscus, and Scopus was conducted. Standardized mean differences (SMD) and 95% confidence intervals were calculated and pooled in a meta-analysis using the random-effects model. The effectiveness of HIIT on waist circumference, muscle mass, resting heart rate, resting systolic and diastolic blood pressure, C-reactive protein, body weight, and body fat were determined. GRADE, risk of bias 2, and PEDro scales were employed. HIIT compared to no intervention, minimal intervention, or usual care did not show significant results in its favor on any of the variables studied, except for the resting heart rate when compared with no intervention (SMD = −0.33; 95% CI: −0.63, −0.04; heterogeneity Q value: 0.14; p = 0.93; I2 = 0%). In addition, HIIT also does not seem to be more effective than moderate-intensity continuous training. Based on the results, it seems that HIIT has almost no significant effects on biological and body composition variables, except for resting heart rate, in patients with MSKD

    Towards soil-transmitted helminths transmission interruption: The impact of diagnostic tools on infection prediction in a low intensity setting in Southern Mozambique

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    Copyright: © 2021 Grau-Pujol et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.[EN] World Health Organization goals against soil-transmitted helminthiases (STH) are pointing towards seeking their elimination as a public health problem: reducing to less than 2% the proportion of moderate and heavy infections. Some regions are reaching WHO goals, but transmission could rebound if strategies are discontinued without an epidemiological evalu-ation. For that, sensitive diagnostic methods to detect low intensity infections and localiza-tion of ongoing transmission are crucial. In this work, we estimated and compared the STH infection as obtained by different diagnostic methods in a low intensity setting. We conducted a cross-sectional study enrolling 792 participants from a district in Mozambique. Two stool samples from two consecutive days were collected from each participant. Samples were analysed by Telemann, Kato-Katz and qPCR for STH detection. We evaluated diagnostic sensitivity using a composite reference standard. By geostatistical methods, we estimated neighbourhood prevalence of at least one STH infection for each diagnostic method. We used environmental, demographical and socioeconomical indicators to account for any existing spatial heterogeneity in infection. qPCR was the most sensitive technique compared to composite reference standard: 92% (CI: 83%– 97%) for A. lumbricoides, 95% (CI: 88%– 98%) for T. trichiura and 95% (CI: 91%– 97%) for hookworm. qPCR also estimated the highest neighbourhood prevalences for at least one STH infection in a low intensity set-ting. While 10% of the neighbourhoods showed a prevalence above 20% when estimating with single Kato-Katz from one stool and Telemann from one stool, 86% of the neighbour-hoods had a prevalence above 20% when estimating with qPCR. In low intensity settings, STH estimated prevalence of infection may be underestimated if based on Kato-Katz. qPCR diagnosis outperformed the microscopy methods. Thus, implementation of qPCR based predictive maps at STH control and elimination programmes would disclose hidden transmission and facilitate targeted interventions for transmission interruption.SIBGP and JM received financial support for this study from Mundo Sano Foundation (www. mundosano.org). JG was personally supported at the beginning of the work by the Ramo´n Areces Foundation and is now funded by the Spanish ‘Juan de la Cierva’ Programme, Ministry of Economy and Competitiveness (FJC-2018-38305). MMV is personally supported by the Spanish ‘Ramo´n y Cajal’ Programme, Ministry of Economy and Competitiveness (RYC-2015-18368). MCP is personally supported by Junta de Castilla y Leo´n and Fondo Social Europeo (LE-135-19). ISGlobal is a member of the CERCA Programme, Generalitat de Catalunya. CISM is supported by the Government of Mozambique and the Spanish Agency for International Development (AECID). Prof. Dr. P.C. Flu Foundation also founded this project. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
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