706 research outputs found

    Thermodynamic modeling of phase separation in manganites

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    We present a phenomenological model based on the thermodynamics of the phase separated state of manganites, accounting for its static and dynamic properties. Through calorimetric measurements on La0.225_{0.225}Pr0.40_{0.40}Ca0.375 _{0.375}MnO3_{3} the low temperature free energies of the coexisting ferromagnetic and charge ordered phases are evaluated. The phase separated state is modeled by free energy densities uniformly spread over the sample volume. The calculations contemplate the out of equilibrium features of the coexisting phase regime, to allow a comparison between magnetic measurements and the predictions of the model. A phase diagram including the static and dynamic properties of the system is constructed, showing the existence of blocked and unblocked regimes which are characteristics of the phase separated state in manganites.Comment: 7 pages, 5 figures, Submitted to Phys. Rev.

    The Role of Probiotics and Prebiotics in the Prevention and Treatment of Obesity

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    Obesity is a global pandemic complex to treat due to its multifactorial pathogenesis—an unhealthy lifestyle, neuronal and hormonal mechanisms, and genetic and epigenetic factors are involved. Scientific evidence supports the idea that obesity and metabolic consequences are strongly related to changes in both the function and composition of gut microbiota, which exert an essential role in modulating energy metabolism. Modifications of gut microbiota composition have been associated with variations in body weight and body mass index. Lifestyle modifications remain as primary therapy for obesity and related metabolic disorders. New therapeutic strategies to treat/prevent obesity have been proposed, based on pre- and/or probiotic modulation of gut microbiota to mimic that found in healthy non-obese subjects. Based on human and animal studies, this review aimed to discuss mechanisms through which gut microbiota could act as a key modifier of obesity and related metabolic complications. Evidence from animal studies and human clinical trials suggesting potential beneficial effects of prebiotic and various probiotic strains on those physical, biochemical, and metabolic parameters related to obesity is presented. As a conclusion, a deeper knowledge about pre-/probiotic mechanisms of action, in combination with adequately powered, randomized controlled follow-up studies, will facilitate the clinical application and development of personalized healthcare strategies.Supported by funds from European Union 7th FP KBBE.2013.2.2-02—MyNewGut Project (“Factors influencing the human gut microbiome and its effect on the development of diet-related diseases and brain development”, Grant Agreement 613979) and from Spanish Ministry of Economy and Competitiveness GD-Brain Projects (SAF2015-69265-c2.2)

    On-board and Ground Visual Pose Estimation Techniques for UAV Control

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    In this paper, two techniques to control UAVs (Unmanned Aerial Vehicles), based on visual information are presented. The first one is based on the detection and tracking of planar structures from an on-board camera, while the second one is based on the detection and 3D reconstruction of the position of the UAV based on an external camera system. Both strategies are tested with a VTOL (Vertical take-off and landing) UAV, and results show good behavior of the visual systems (precision in the estimation and frame rate) when estimating the helicopter¿s position and using the extracted information to control the UAV

    Calidad de vida en pacientes de baja visión con degeneración macular asociada a la edad

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    I Congreso Online Internacional de Salud Visual, 12-15 de Marzo de 2019, http://www.congresodesaludvisual.orgAntecedentes/objetivos: La calidad de vida (CV) de las personas de baja visión (BV) con DMAE afecta gravemente a la capacidad para realizar actividades cotidianas. Los objetivos son analizar y evaluar la bibliografía científica que estudia la CV en pacientes de BV con DMAE. Método: Se realizó una revisión y un estudio bibliométrico a través de las publicaciones existentes, hasta febrero de 2018. Se consultó en MEDLINE, SCOPUS Y WOS. Los descripciones utilizados fueron “baja visión”, “degeneración macular”, “calidad de vida”. Se incluyeron trabajos originales que estudian la CV en pacientes con BV y DMAE, realizados en cualquier país y que disponen de texto completo. Se excluyeron estudios no originales, informes de casos, estudios de animales, estudios con idioma distinto al inglés o español y estudios que validen el instrumento. Resultados: Se han identificado 501 artículos, después de eliminar los duplicados y aplicar los criterios de exclusión, se incluyeron 52 artículos que representan la información más relevante. Con mucha diferencia América es el continente que más investiga (45%), seguido de Europa (27%). Las dos revistas que más publican son: IOVS (12%) y Archives of Ophthalmology (10%). La Univ. que más ha investigado de Melbourne (12%). Dentro de los 11 autores que más publican, se encuentran Keeffe y Lamoureux. Con relación al género de los autores, no existen diferencias en el número de publicaciones aunque si en el orden de autoría, ellos ocupan la 1ª posición, mientras que ellas tienen un porcentaje más alto como corresponding. Los artículos incluidos además de hablar de la CV en paciente de BV con DMAE también abordan otros temas como la depresión, la importancia de la luz en a la hora de realizar actividades cotidianas, la medida de la AV, la efectividad de la rehabilitación y la velocidad de lectura. Las personas con BV y DMAE muestran una serie de problemas relacionados con su funcionalidad; en concreto, la relación con la movilidad, tienen un riesgo importante de caídas y fracturas. En lo que se refiere a la salud mental, como sentimientos de aislamiento social, angustia emocional y depresión. Además, el impedimento visual ha sido asociado con un menor bienestar, expresado por la pérdida de interés y la incapacidad para disfrutar de las actividades. Conclusiones: Se concluye que los pacientes con DMAE experimentan mayores pérdidas en la CV relacionada con la salud que los pacientes de la misma edad con otras enfermedades crónicas. Estas disminuciones en la CV se explican claramente por la pérdida de la AV y las limitaciones que ésta les afecta a la hora de realizar actividades en su día a día

    Variable rate spraying in varied micro-meteorological conditions

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    This study evaluated effects of crosswind on the variable rate sprayer application treatments spray coverage and deposition on different citrus canopy sizes.  The axial-fan airblast sprayer retrofitted with variable liquid- and air-assist rates was field-tested with different crosswind conditions on small (about 2 m tall and < 1.5 m wide) and medium-sized (about 3 m tall and < 2.5 m wide) canopies.  Crosswinds of 1.3, 2.7, and 4.0 ms-1 on the canopies being sprayed were generated using the stationary conical air shaker as the air blower unit.  Water sensitive papers (WSPs) were used to collect droplet deposits and image processing software was used to analyze the WSPs scanned at 600 dpi.  Percent spray coverage on the WSPs was found to be one of the most suited parameters to evaluate the effectiveness of spray application treatments.  Overall, the variable rate spray application treatments had comparable spray coverage on respective canopies (front, middle, and across WSP locations in the canopy) during all crosswind conditions.  For both types of canopies, spray coverage was higher on the canopy front and decreased as the spray penetrated inside (i.e. canopy middle) and across.  Due to coalescing, larger droplets (Dv,0.5 [volume median diameter] = 838 to 2,624 µm) were formed on the WSPs located on canopy front, whereas coalescing reduced as the spray penetrated inside (Dv,0.5 = 391 to 1,625 µm on canopy middle) and across the canopy (Dv,0.5 = 307 to 508 µm).    Keywords: airblast sprayer, adjustable air-assistance, crosswind, spray coverage, citru

    Structural and functional evidence for membrane docking and disruption sites on phospholipase A2-like proteins revealed by complexation with the inhibitor suramin

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    Local myonecrosis resulting from snakebite envenomation is not efficiently neutralized by regular antivenom administration. This limitation is considered to be a significant health problem by the World Health Organization. Phospholipase A2-like (PLA2-like) proteins are among the most important proteins related to the muscle damage resulting from several snake venoms. However, despite their conserved tertiary structure compared with PLA2s, their biological mechanism remains incompletely understood. Different oligomeric conformations and binding sites have been identified or proposed, leading to contradictory data in the literature. In the last few years, a comprehensive hypothesis has been proposed based on fatty-acid binding, allosteric changes and the presence of two different interaction sites. In the present study, a combination of techniques were used to fully understand the structural-functional characteristics of the interaction between suramin and MjTX-II (a PLA2-like toxin). In vitro neuromuscular studies were performed to characterize the biological effects of the protein-ligand interaction and demonstrated that suramin neutralizes the myotoxic activity of MjTX-II. The high-resolution structure of the complex identified the toxin-ligand interaction sites. Calorimetric assays showed two different binding events between the protein and the inhibitor. It is demonstrated for the first time that the inhibitor binds to the surface of the toxin, obstructing the sites involved in membrane docking and disruption according to the proposed myotoxic mechanism. Furthermore, higher-order oligomeric formation by interaction with interfacial suramins was observed, which may also aid the inhibitory process. These results further substantiate the current myotoxic mechanism and shed light on the search for efficient inhibitors of the local myonecrosis phenomenon.Peer Reviewe

    Sex and heavy metals: study of sexual dimorphism in response to soil pollution

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    In dioecious plants, males and females often show distinct morphological, physiological and life history traits as result of their different demands for reproduction. Such sexual dimorphism is likely to be accentuated under stressful conditions, such as that imposed by exposure to heavy metals. However little is known about the response of dioecious plants to stress by heavy metals. Here we use the dioecious herb Silene latifolia to investigate the growth and reproduction of males and females growing in soil polluted with either Cu or Cd. We also examined whether the sexes differed in the patterns of metal accumulation in their tissues. Patterns of biomass allocation to reproduction, roots, leaves and shoots (stem and leaves) were compared in male and female S. latifolia plants that were harvested after growing for 14 weeks in different soil conditions (non-polluted soil, Cu-polluted soil and Cd-polluted soil). In addition, patterns of metal accumulation between the sexes were also compared post-harvest by analysing the metal content in their tissues. Overall, metals decreased plants’ total dry mass allocated to leaves and to roots- particularly in males. Females accumulated more Cu in their tissues. However, this did not seem to correspond with females performing worse (in terms of growth and reproduction) than males when growing in soil polluted with this metal. Despite males and females having similar levels of Cd in their tissues, males seemed to have lower tolerance to this metal, as indicated by a lower total and leaf dry mass than females, and also by a lower number of flowers when growing in Cd-polluted soil. We also found contrasting differences in female seed production due to heavy metals, with number of seeds (but not mass) decreasing with Cu and increasing with Cd. Our results indicate the presence of sexual dimorphism in response to heavy metals, with the sexes differing in both patterns of accumulation and tolerance
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