644 research outputs found

    Gap variability upon packing in organic photovoltaics.

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    The variation of the HOMO-LUMO band gap is explored for varying packing arrangements of the 4mod BT-4TIC donor-acceptor molecule pair, by means of a high-throughput ab-initio random structure search of packing possibilities. 350 arrangements of the dimer have been relaxed from initial random dispositions, using non-local density-functional theory. We find that the electronic band gap varies within 0.3 eV, and that this magnitude, the binding energy, and the geometry are not significantly correlated. A clearly favoured structure is found with a binding energy of 1.75±0.07 eV, with all but three other arrangements displaying values of less than one third of this highest binding one, which involves the aliphatic chain of 4TIC

    Role of twin boundaries on the vortex dynamics in YBa2_2Cu3_3O7_7

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    By means of a novel technique of rotating the applied current we have directly measured the influence of twin boundaries on the vortex motion in a YBa2_2Cu3_3O7_7 single crystal. The results indicate that the effect of twin planes on the vortex dynamics starts to develop below a certain temperature, being responsible for an anisotropic viscosity in the vortex liquid state and a guided motion in the solid state.Comment: 4 pages, 4 figure

    LIDERAZGO DEPORTIVO DE LA MUJER. UNA VISIÓN CRÍTICA WOMEN SPORT LEADERSHIP. A CRITICAL VISION

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    El presente artículo tiene como propósito develar la actuación de la mujer en el mundo deportivo, específicamente liderazgo en puestos de poder y decisión en diferentes niveles de actuación, sea a nivel olímpico, nacional, regional y municipal en Venezuela. Para cumplir con los objetivos planteados se utilizó la Teoría Socio-Critica como elemento de sustento documental para darle una visión más amplia a la problemática de desigualdad y a la discriminación de género lo cual es incompatible con la democracia. La igualdad entre hombres y mujeres es un principio universal reconocido en la Carta de las Naciones Unidas (1945), la Declaración de Derechos Humanos (1948) la Convención de las Naciones Unidas (1979) sobre la eliminación de cualquierforma de discriminación contra las mujeres. En el caso del Comité Olímpico Internacional, las Federaciones Internacionales, los Comités Olímpicos Nacionales; Ministerio de Deporte, Institutos Regionales e Institutos Municipales se han dado avances y pasos significativos para la igualdad de oportunidades pero aún existen importantes retos relacionados con las necesidades, intereses, deseos y demandas de las mujeres. En lo referente a Venezuela es muy poca la participación de la mujer en calidad de gerente y líder deportivo, a pesar de la aprobación de una Ley Contra la Violencia de la Mujer (2007), la creación del Ministerio de la Mujer (2011) y de la alianza de Ministerio de la Mujer y Ministerio de la Juventud y Deporte (2011) para impulsar programas y proyectos que atiendas las necesidades de las mujeres a nivel nacional, lo cual aún todavía no se ha logrado completamente

    Perception about the importance of feeding in a group of hematologic cancer patients

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    Introducción: Los pacientes oncohematológicos presentan habitualmente déficits nutricionales derivados de su enfermedad, sus tratamientos y efectos secundarios, etc. Sin embargo, apenas existen datos descriptivos del empleo de recomendaciones dietéticas, y de la auto-percepción del paciente de su utilidad en su enfermedad. Objetivos: Evaluar la percepción de la importancia de la alimentación en un grupo de pacientes con cáncer hematológico. Materiales y métodos: 111 pacientes oncohematológicos auto-registraron un cuestionario con preguntas sociosanitarias y de percepción personal de la importancia de la alimentación en su enfermedad. Resultados: La edad media fue 40,0 ± 12,8 años (64,86% mujeres). El diagnóstico y el tratamiento más frecuente fue linfoma (83,78%) y quimioterapia (92,80%). Un 75% consideró “muy importante” la relación entre enfermedad oncohematológica y estado nutricional. Sólo un 54,1% recibió consejo dietético. Y un 53,2% y 50,5% consideró que el consumo de suplementos nutricionales mejoraría su calidad de vida y/o enfermedad respectivamente. Conclusiones: Un porcentaje importante de pacientes presentaron estados avanzados de su enfermedad. Sin embargo, la mitad del colectivo no había recibido pautas dietéticas a pesar del elevado interés por recibir atención nutricional. Por tanto, la valoración nutricional del paciente oncohematológico así como la implementación de un soporte nutricional personalizado deberían formar parte de la práctica clínica habitualIntroduction: Oncohematologic patients usually present nutritional deficits associated with the disease, the treatments and side effects, etc. However, there are hardly any descriptive data about the dietary recommendations used and the patient’s self-perception of its usefulness in their disease. Aim: To assess the self-perception of the nutritional importance in a group of oncohematologic patients. Materials and methods: 111 oncohematologic patients self-reported a questionnaire containing items about socio-sanitary data and self-perception of the nutritional importance in their disease. Results: The mean age was 40.0 ± 12.8 years (64.86% women). The most frequent diagnosis and treatment was lymphoma (83.78%) and chemoteraphy (92.80%). 75% considered “very important” relationship between oncohematologic disease and nutritional status. Only 54.1% received dietary advice. And 53.2% and 50.5% considered that the use of nutritional supplements improve quality of life and/or disease respectively. Conclusions: A significant percentage of patients had advanced stages of their disease. However, half the group had not received dietary advice despite high interest in receiving nutritional care. Therefore, the nutritional assessment and the personalized nutritional support implementation of the patient should be included in routine clinical practic

    Steady state rheological behaviour of multi-component magnetic suspensions

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    In this paper, we study the rheological behaviour (in the absence of a magnetic field and upon its application) of multi-component magnetic suspensions that consist of a mixture of magnetic (iron) and non-magnetic (PMMA) particles dispersed in a liquid carrier. These suspensions exhibit considerably higher viscosity and yield stress in the absence of a magnetic field than single-component suspensions of the same solid fraction, as a consequence of the adsorption of the iron particles on the PMMA ones. The adsorbed layer of iron particles on the PMMA ones is observed through optical microscopy of dilute samples and confirmed by attenuated total reflectance. Microscopic observations also show that the resulting non-magnetic-core–magnetic-shell composites move upon magnetic field application and aggregate into particle structures aligned with the applied field. These structures, which consist of both types of particles, give rise to high values of the static and dynamic yield stresses upon field application. Actually, both quantities are much higher than those of a suspension with the same volume fraction of magnetic particles, and increase when the amount of non-magnetic ones increases. These trends are adequately predicted by a theoretical model that considers that the main contribution to the yield stress is the change of the suspension magnetic permeability when particle chains are deformed by the shear.This work was supported by Projects P08-FQM-3993, P09-FQM-4787 (Junta de Andalucía, Spain) and FIS2009-07321 (MICINN, Spain). In addition, L. Rodríguez-Arco and M.T. López-López acknowledge financial support by Secretaría de Estado de Educación, Formación Profesional y Universidades (MECD, Spain) through its FPU program and the University of Granada (Spain), respectively

    UMBRAL DE DISCRIMINACIÓN DE DOS PUNTOS EN DISTINTAS REGIONES ANATÓMICAS EN MUJERES

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    Este proyecto se realiza con el objetivo de realizar una prueba de discriminación de dos puntos en distintas regiones anatómicas en un grupo de doce mujeres estudiantes de Medicina. La anterior prueba logra medir de una forma eficaz la sensibilidad somática del paciente. Se determina que la precisión de la ubicación donde se realiza el estímulo depende de los campos sensoriales de los receptores. En conclusión, se afirma que existe una diferencia en el umbral de discriminación entre dos puntos en las diferentes regiones anatómicas.Este proyecto se realiza con el objetivo de realizar una prueba de discriminación de dos puntos en distintas regiones anatómicas en un grupo de doce mujeres estudiantes de Medicina. La anterior prueba logra medir de una forma eficaz la sensibilidad somática del paciente. Se determina que la precisión de la ubicación donde se realiza el estímulo depende de los campos sensoriales de los receptores. En conclusión, se afirma que existe una diferencia en el umbral de discriminación entre dos puntos en las diferentes regiones anatómicas

    Generation of genipin cross-linked fibrin-agarose hydrogel tissue-like models for tissue engineering applications

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    Generation of biomimetic and biocompatible artificial tissues is the basic research objective for tissue engineering (TE). In this sense, the biofabrication of scaffolds that resemble the tissues’ extracellular matrix (ECM) is an essential aim in this field. Uncompressed and nanostructured fibrin-agarose hydrogels (FAH and NFAH respectively) emerged as promising scaffold in TE, but its structure and biomechanical properties must be improved in order to broad their TE applications. Here we generated and characterized novel membranelike models with increased structural and biomechanical properties based on the chemical cross-linking of FAH and NFAH with genipin (GP at 0.1, 0.25, 0.5 and 0.75%). Furthermore, scaffolds were subjected to rheological (G, G’, G” modulus), ultrastructural and ex vivo biocompatibility analyses. Results showed that all GP concentrations increased the stiffness (G) and especially the elasticity (G’) of FAH and NFAH. Ultrastructural analyses demonstrated that GP and nanostructuration of FAH allowed controlling the porosity of FAH. In addition, biological studies revealed that higher concentration of GP significantly decreased the cell viability. Finally, this study demonstrated the possibility to generate natural FAH and NFAH with improved structural and biomechanical properties by using GP. However, further in vivo studies are needed in order to demonstrate the biocompatibility, biodegradability and regeneration capability of these cross-linked scaffolds

    The Role of Autophagy in Eye Diseases

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    This research was funded by the Ophthalmological Network OFTARED (Enfermedades oculares: Prevención, detección precoz, tratamiento y rehabilitación de las patologías oculares) (RD16/0008/0005 and RD16/0008/0026) of the Institute of Health of Carlos III of the Spanish Ministry of Economy and by the European programme FEDER; and Network RETiBRAIN (La retina un modelo para investigar Neuroprotección en patologías del Sistema Nervioso Central) (RED2018-102499-T) of Spanish Ministry of Science and Innovation. And J.A.F.-A. is currently funded by a Predoctoral Fellowship (FPU17/01023) from the Spanish Ministry of Science, Innovation, and Universities; and I.L.-C. is currently funded by a Predoctoral Fellowship (CT42/18-CT43/18) from the Complutense University of Madrid.Autophagy is a catabolic process that ensures homeostasis in the cells of our organism. It plays a crucial role in protecting eye cells against oxidative damage and external stress factors. Ocular pathologies of high incidence, such as age-related macular degeneration, cataracts, glaucoma, and diabetic retinopathy are of multifactorial origin and are associated with genetic, environmental factors, age, and oxidative stress, among others; the latter factor is one of the most influential in ocular diseases, directly affecting the processes of autophagy activity. Alteration of the normal functioning of autophagy processes can interrupt organelle turnover, leading to the accumulation of cellular debris and causing physiological dysfunction of the eye. The aim of this study is to review research on the role of autophagy processes in the main ocular pathologies, which have a high incidence and result in high costs for the health system. Considering the role of autophagy processes in cell homeostasis and cell viability, the control and modulation of autophagy processes in ocular pathologies could constitute a new therapeutic approach.Depto. de Inmunología, Oftalmología y ORLFac. de MedicinaTRUEUnión EuropeaMinisterio de Ciencia e Innovación (España)Instituto de Salud Carlos IIIUniversidad Complutense de Madridpu

    Investigating transition state resonances in the time domain by means of Bohmian mechanics: The F+HD reaction

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    In this work, we investigate the existence of transition state resonances on atom-diatom reactive collisions from a time-dependent perspective, stressing the role of quantum trajectories as a tool to analyze this phenomenon. As it is shown, when one focusses on the quantum probability current density, new dynamical information about the reactive process can be extracted. In order to detect the effects of the different rotational populations and their dynamics/coherences, we have considered a reduced two-dimensional dynamics obtained from the evolution of a full three-dimensional quantum time-dependent wave packet associated with a particular angle. This reduction procedure provides us with information about the entanglement between the radial degrees of freedom (r,R) and the angular one (\gamma), which can be considered as describing an environment. The combined approach here proposed has been applied to study the F+HD reaction, for which the FH+D product channel exhibits a resonance-mediated dynamics.Comment: 12 pages, 9 figure
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