395 research outputs found

    Linear Strain Tensors on Hyperbolic Surfaces and Asymptotic Theories for Thin Shells

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    We perform a detailed analysis of the solvability of linear strain equations on hyperbolic surfaces. We prove that if the surface is a smooth noncharacteristic region, any first order infinitesimal isometry can be matched to an infinitesimal isometry of an arbitrarily high order. The implications of this result for the elasticity of thin hyperbolic shells are discussed

    Disruptores endocrinos. El caso particular de los xenobióticos estrogénicos. II Estrógenos sintéticos

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    In recent years, it has been demonstrated that endocrine systems of living beings can be altered by many chemical substances of anthropogenic origin, designated as endocrine disrupters. There are growing concerns about the number of these endocrine disrupters. It has not been possible to define a single chemical structure that allows the classification of a chemical compound as a mimic of female sex hormones, so that chemical structures similar to natural estrogens, based on cyclopentanoperhydrophenanthrene, share their hormonal effect with stilbenes, bisphenols, alkylphenols, dioxins, furans and parabenes. The recognition of estrogenic activity in different biological models has been used to update the list of xenoestrogens and reveal sources of human exposure that were previously unknown. New previously unsuspected chemical compounds have been added to the list, as well as their precursors, metabolites and degradation products, whose effects are only now beginning to be recognised.En los últimos años se ha puesto en evidencia que muchas sustancias químicas de origen antropogénico son capaces de alterar el sistema endocrino de los seres vivos y se ha acuñado el nombre de disruptores endocrinos para definirlas. El número de disruptores endocrinos es una preocupación creciente si se añade a la inclusión de nuevos compuestos químicos, hasta ahora insospechados, la información generada sobre sus precursores, metabolitos y productos de degradación que tan solo ahora empiezan a conocerse. No se ha podido definir una estructura química única que permita clasificar a un compuesto químico como mimetizador de las hormonas sexuales femeninas, de tal manera que estructuras químicas similares a los estrógenos naturales, basados en el ciclopentanoperhidrofenantreno, comparten con los estilbenos, bisfenoles, bifenilos, alquilfenoles, dioxinas, furanos y parabenes su efecto hormonal estrogénico. El reconocimiento de la actividad estrogénica en diferentes modelos biológicos se ha utilizado para actualizar el censo de xenoestrógenos y poner de manifiesto fuentes de exposición humana hasta el momento insospechadas

    Measuring the gas content of low-mass planets orbiting F-stars

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    Context. Giant planets are known to dominate the long-term stability of planetary systems due to their prevailing gravitational interactions, but they are also thought to play an important role in planet formation. Observational constraints improve our understanding of planetary formation processes such as the delivery of volatile-rich planetesimals from beyond the ice line into the inner planetary system. Additional constraints may come from studies of the atmosphere, but almost all such studies of the atmosphere investigate the detection of certain species, and abundances are not routinely quantitatively measured. Aims. Accurate measurements of planetary bulk parameters – that is, mass and density – provide constraints on the inner structure and chemical composition of transiting planets. This information provides insight into properties such as the amounts of volatile species, which in turn can be related to formation and evolution processes. Methods. The Transiting Exoplanet Survey Satellite (TESS) reported a planetary candidate around HD 190622 (TOI-1054), which was subsequently validated and found to merit further characterization with photometric and spectroscopic facilities. The KESPRINT collaboration used data from the High Accuracy Radial Velocity Planet Searcher (HARPS) to independently confirm the planetary candidate, securing its mass, and revealing the presence of an outer giant planet in the system. The CHEOPS consortium invested telescope time in the transiting target in order to reduce the uncertainty on the radius, improving the characterization of the planet. Results. We present the discovery and characterization of the planetary system around HD 190622 (TOI-1054). This system hosts one transiting planet, which is smaller than Neptune (3.087-0.053+0.058REarth, 7.7 ± 1.0 MEarth) but has a similar bulk density (1.43 ± 0.21 g cm−3) and an orbital period of 16 days; and a giant planet, not known to be transiting, with a minimum mass of 227.0 ± 6.7 MEarth in an orbit with a period of 315 days. Conclusions. Our measurements constrain the structure and composition of the transiting planet. HD 190622b has singular properties among the known population of transiting planets, which we discuss in detail. Among the sub-Neptune-sized planets known today, this planet stands out because of its large gas content

    Coenzyme Q10 Supplementation for the Reduction of Oxidative Stress: Clinical Implications in the Treatment of Chronic Diseases

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    Apart from its main function in the mitochondria as a key element in electron transport, Coenzyme Q10 (CoQ10) has been described as having multiple functions, such as oxidant action in the generation of signals and the control of membrane structure and phospholipid and cellular redox status. Among these, the most relevant and most frequently studied function is the potent antioxidant capability of its coexistent redox forms. Different clinical trials have investigated the effect of CoQ10 supplementation and its ability to reduce oxidative stress. In this review, we focused on recent advances in CoQ10 supplementation, its role as an antioxidant, and the clinical implications that this entails in the treatment of chronic diseases, in particular cardiovascular diseases, kidney disease, chronic obstructive pulmonary disease, non-alcoholic fatty liver disease, and neurodegenerative diseases. As an antioxidant, CoQ10 has proved to be of potential use as a treatment in diseases in which oxidative stress is a hallmark, and beneficial effects of CoQ10 have been reported in the treatment of chronic diseases. However, it is crucial to reach a consensus on the optimal dose and the use of different formulations, which vary from ubiquinol or ubiquinone Ubisol-Q10 or Qter®, to new analogues such as MitoQ, before we can draw a clear conclusion about its clinical use. In addition, a major effort must be made to demonstrate its beneficial effects in clinical trials, with a view to making the implementation of CoQ10 possible in clinical practice

    Modeling Population Growth of Pyrenean Chamois (Rupicapra p. pyrenaica) by Using P-Systems

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    P systems provide a high level computational modeling framework which integrates the structural and dynamic aspects of ecosystems in a comprehensive and relevant way. In previous works, several ecosystems modeled by using P systems were presented. The good results obtained encourage us to study new ecosystems such as the one presented in this paper. Pyrenean Chamois (Rupicapra p. pyrenaica) is an ungulate species inhabiting the Catalan Pyrenees. In recent years, several diseases have caused a drastic decrease in the number of individuals. Since they provide significant economic contributions in the area and constitutes an important food resource for obligate and facultative scavengers, it is very interesting to provide a model in order to facilitate the management of their ecosystems

    Altered myogenesis and premature senescence underlie human TRIM32-related myopathy

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    TRIM32 is a E3 ubiquitin -ligase containing RING, B-box, coiled-coil and six C-terminal NHL domains. Mutations involving NHL and coiled-coil domains result in a pure myopathy (LGMD2H/STM) while the only described mutation in the B-box domain is associated with a multisystemic disorder without myopathy (Bardet-Biedl syndrome type11), suggesting that these domains are involved in distinct processes. Knock-out (T32KO) and knockin mice carrying the c.1465G > A (p.D489N) involving the NHL domain (T32KI) show alterations in muscle regrowth after atrophy and satellite cells senescence. Here, we present phenotypical description and functional characterization of mutations in the RING, coiled-coil and NHL domains of TRIM32 causing a muscle dystrophy. Reduced levels of TRIM32 protein was observed in all patient muscle studied, regardless of the type of mutation (missense, single amino acid deletion, and frameshift) or the mutated domain. The affected patients presented with variable phenotypes but predominantly proximal weakness. Two patients had symptoms of both muscular dystrophy and Bardet-Biedl syndrome. The muscle magnetic resonance imaging (MRI) pattern is highly variable among patients and families. Primary myoblast culture from these patients demonstrated common findings consistent with reduced proliferation and differentiation, diminished satellite cell pool, accelerated senescence of muscle, and signs of autophagy activation.Health Institute Carlos III PI16-01843 JR15/00042FEDER PI16-01843 JR15/00042Fundación Progreso y Salud, Junta de Andalucía PI-0085-2016Australian National Health and Medical Research Council (NHMRC) APP1122952 APP111751

    Altered myogenesis and premature senescence underlie human TRIM32-related myopathy

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    TRIM32 is a E3 ubiquitin -ligase containing RING, B-box, coiled-coil and six C-terminal NHL domains. Mutations involving NHL and coiled-coil domains result in a pure myopathy (LGMD2H/STM) while the only described mutation in the B-box domain is associated with a multisystemic disorder without myopathy (Bardet-Biedl syndrome type11), suggesting that these domains are involved in distinct processes. Knock-out (T32KO) and knockin mice carrying the c.1465G > A (p.D489N) involving the NHL domain (T32KI) show alterations in muscle regrowth after atrophy and satellite cells senescence. Here, we present phenotypical description and functional characterization of mutations in the RING, coiled-coil and NHL domains of TRIM32 causing a muscle dystrophy. Reduced levels of TRIM32 protein was observed in all patient muscle studied, regardless of the type of mutation (missense, single amino acid deletion, and frameshift) or the mutated domain. The affected patients presented with variable phenotypes but predominantly proximal weakness. Two patients had symptoms of both muscular dystrophy and Bardet-Biedl syndrome. The muscle magnetic resonance imaging (MRI) pattern is highly variable among patients and families. Primary myoblast culture from these patients demonstrated common findings consistent with reduced proliferation and differentiation, diminished satellite cell pool, accelerated senescence of muscle, and signs of autophagy activation.Health Institute Carlos III PI16-01843 JR15/00042FEDER PI16-01843 JR15/00042Fundación Progreso y Salud, Junta de Andalucía PI-0085-2016Australian National Health and Medical Research Council (NHMRC) APP1122952 APP111751
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