448 research outputs found

    Molecular Modeling of Adsorption of 5-Aminosalicylic Acid in the Halloysite Nanotube

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    Halloysite nanotubes are becoming interesting materials for drug delivery. The knowledge of surface interactions is important for optimizing this application. The aim of this work is to perform a computational study of the interaction between 5-aminosalicylic acid (5-ASA) drug and halloysite nanotubes for the development of modified drug delivery systems. The optimization of this nanotube and the adsorption of different conformers of the 5-ASA drug on the internal surface of halloysite in the presence and absence of water were performed using quantum mechanical calculations by using Density Functional Theory (DFT) and methods based on atomistic force fields for molecular modeling, respectively.This work is funded by the Andalusian Government projects (RNM1897) and the MINECO project FIS2016-77692-C2-2P. It also supported by the Egyptian Cultural Affairs and Missions Sector (Plan 2013-2014), Ministry of Higher Education

    Development of a grid connected micro wind generator. A practical activity for the course on electric generation with wind energy

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    This paper describes a practical activity, part of the renewable energy course where the students have to build their own complete wind generation system, including blades, PM-generator, power electronics and control. After connecting the system to the electric grid the system has been tested during real wind scenarios. The paper will describe the electric part of the work surface-mounted permanent magnet machine design criteria as well as the power electronics part for the power control and the grid connection. A Kalman filter is used for the voltage phase estimation and current commands obtained in order to control active and reactive power. The connection to the grid has been done and active and reactive power has been measured in the system

    Relaxation behavior of semiflexible polymers at very low frequencies

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    [EN] The dielectric activity of poly(monocyclohexylmethylene itaconate) (PMCI) and poly(dicyclohexylmethylene itaconate) (PDCI) in the glassy region and in the glass-rubber transition is studied by thermostimulated discharge current (TSDC) techniques. The spectra obtained by global TSDC experiments show a prominent alpha-glass-rubber relaxation peak with maxima located at 97 and 55 degrees C for PMCI and PDCI, respectively, following in decreasing order of temperature for a well developed beta absorption and a comparatively low intensity relaxation. Better resolution of the relaxation behavior of these polymers in the glassy region is obtained by calculating the components of the complex dielectric permittivity epsilon* at extremely low frequencies from partial TSDC experiments. The ac spectra thus obtained suggest that the beta absorption is composed by two relaxations, each of them presumably associated with the motions of a side group. The differences observed in these spectra with those reported for the beta mechanical relaxation reported for these polymers in the literature are interpreted in terms of the restrictions that the side groups produce in the conformational space of phase of the backbone. These restrictions also explain the small changes in enthalpy in the glass-rubber transition which preclude the possibility of obtaining the glass-rubber transition temperature of these polymers by differential scanning calorimetric techniques. (C) 1997 American Institute of Physics.Díaz Calleja, R.; Sanchis Sánchez, MJ.; Alvarez, C.; Riande, E. (1997). Relaxation behavior of semiflexible polymers at very low frequencies. Journal of Applied Physics. 81(8):3685-3691. doi:10.1063/1.364743S3685369181

    Algal-fungal mutualism: cell recognition and maintenance of the symbiotic status of lichens

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    Lichens are specific symbiotic associations between photosynthetic algae or cyanobacteria and heterotrophic fungi forming a double entity in which both components coexist. Specificity required for the lichen establishment can be defined in this context as the preferential, but not exclusive, association of a biont with another, since the algal factor susceptible to be recognized is an inducible protein. Recognition of compatible algal cells is performed by specific lectins produced and secreted by the potential mycobiont. Some lectins from phycolichens and cyanolichens are glycosylated arginases which bind to an algal cell wall receptor, identified as a a-1, 4-polygalactosylated urease. However, other ligands exist which bind other lectins specific for mannose or glucose. This implies that, after recognition of a potential, compatible partner, other fungal lectins could determine the final success of the association. Since the fungus can parasitize non - recognized partners during the development of the association, the success after the first contact needs of a set of algal cells, the number of which was sufficient to prevent that the death of a certain number of them makes fail the symbiosis. Fungal lectins act as chemo tactic factors in such a way that algae and cyanobacteria move towards the hyphae, to acquire that critical size of the colony, by means of successive contractions and relaxation of the actomyosin cytoskeleton in absence of any motile appendages

    The Effect of the Presence of Amino Acids on the Precipitation of Inorganic Chemical-Garden Membranes: Biomineralization at the Origin of Life

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    If life developed in hydrothermal vents, it would have been within mineral membranes. The first proto-cells must have evolved to manipulate the mineral membranes that formed their compartments in order to control their metabolism. There must have occurred a biological takeover of the self-assembled mineral structures of the vents, with the incorporation of proto-biological molecules within the mineral membranes to alter their properties for life’s purposes. Here, we study a laboratory analogue of this process: chemical-garden precipitation of the amino acids arginine and tryptophan with the metal salt iron chloride and sodium silicate. We produced these chemical gardens using different methodologies in order to determine the dependence of the morphology and chemistry on the growth conditions, as well as the effect of the amino acids on the formation of the iron-silicate chemical garden. We compared the effects of having amino acids initially within the forming chemical garden, corresponding to the internal zones of hydrothermal vents, or else outside, corresponding to the surrounding ocean. The characterization of the formed chemical gardens using X-ray diffraction, Fourier transform infrared spectroscopy, elemental analysis, and scanning electron microscopy demonstrates the presence of amino acids in these structures. The growth method in which the amino acid is initially in the tablet with the iron salt is that which generated chemical gardens with more amino acids in their structures.European Commission P-18-RT-3786Spanish Andalusian CA1712

    Longitudinal Changes in Response to a Cycle-Run Field Test of Young Male National "Talent identification" and Senior Elite Triathlon Squads.

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    This study investigated the changes in cardiorespiratory response and running performance of 9 male ?Talent Identification? (TID) and 6 male Senior Elite (SE) Spanish National Squad triathletes during a specific cycle-run test. The TID and SE triathletes (initial age 15.2±0.7 vs. 23.8±5.6 years, p=0.03; tests through the competitive period and the preparatory period, respectively, of two consecutive seasons: Test 1 was an incremental cycle test to determine the ventilatory threshold (Thvent); Test 2 (C-R) was 30 min constant load cycling at the Thvent power output followed by a 3-km time trial run; and Test 3 (R) was an isolated 3-km time trial control run, in randomized counterbalanced order. In both seasons the time required to complete the C-R 3-km run was greater than for R in TID (11:09±00:24 vs. 10:45±00:16 min:ss, pmenor que 0.01; and 10:24±00:22 vs. 10:04±00:14, p=0.006, for season 2005/06 and 2006/07, respectively) and SE (10:15±00:19 vs. 09:45±00:30, pmenor que 0.001 and 09:51±00:26 vs. 09:46±00:06, p= 0.02 for season 2005/06 and 2006/07, respectively). Compared to the first season, completion of the time trial run was faster in the second season (6.6%, pmenor que 0.01 and 6.4%, pmenor que 0.01, for C-R and R test, respectively) only in TID. Changes in post-cycling run performance were accompanied by changes in pacing strategy but only slight or non-significant changes in the cardiorespiratory response. Thus, the negative effect of cycling on performance may persist, independently of the period, over two consecutive seasons in TID and SE triathletes; however A improvements over time suggests that monitoring running pacing strategy after cycling may be a useful tool to control performance and training adaptations in TID. O2max 77.0±5.6 vs. 77.8±3.6 mL·kg-1·min-1, NS) underwent three TE D EP C

    Central relaxin-3 receptor (RXFP3) activation impairs social recognition and modulates ERK-phosphorylation in specific GABAergic amygdala neurons

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    This is a pre-print of an article published in Brain Structure and Function. The final authenticated version is available online at: https://doi.org/10.1007/s00429-018-1763-5In mammals, the extended amygdala is a neural hub for social and emotional information processing. In the rat, the extended amygdala receives inhibitory GABAergic projections from the nucleus incertus (NI) in the pontine tegmentum. NI neurons produce the neuropeptide relaxin-3, which acts via the Gi/o-protein-coupled receptor, RXFP3. A putative role for RXFP3 signalling in regulating social interaction was investigated by assessing the effect of intracerebroventricular infusion of the RXFP3 agonist, RXFP3-A2, on performance in the 3-chamber social interaction paradigm. Central RXFP3-A2, but not vehicle, infusion, disrupted the capacity to discriminate between a familiar and novel conspecific subject, but did not alter differentiation between a conspecific and an inanimate object. Subsequent studies revealed that agonist-infused rats displayed increased phosphoERK(pERK)-immunoreactivity in specific amygdaloid nuclei at 20 min post-infusion, with levels similar to control again after 90 min. In parallel, we used immunoblotting to profile ERK phosphorylation dynamics in whole amygdala after RXFP3-A2 treatment; and multiplex histochemical labelling techniques to reveal that after RXFP3-A2 infusion and social interaction, pERK-immunopositive neurons in amygdala expressed vesicular GABA-transporter mRNA and displayed differential profiles of RXFP3 and oxytocin receptor mRNA. Overall, these findings demonstrate that central relaxin-3/RXFP3 signalling can modulate social recognition in rats via effects within the amygdala and likely interactions with GABA and oxytocin signalling

    Educación inclusiva, un gran desafío

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    Es necesario entender que la inclusión representa un gran reto para las escuelas y la sociedad. Con la finalidad de cimentar un proceso de inclusión en las escuelas, este artículo recoge aspectos que resultan fundamentales para entender las perspectivas de padres de familia y docentes en cuanto a las necesidades educativas de los niños inclusivos para que se integren en la sociedad de diferentes formas: como estudiante, trabajador o miembro de la familia en la cual viven. En este trabajo se pretende profundizar un tema actual y preocupante en la educación, la inclusión en la formación básica regular, considerando la perspectiva de los docentes y padres de los estudiantes inclusivos. Como objetivo principal buscamos determinar de qué manera las acciones que se llevan a cabo en la institución educativa contribuyen a la inserción de los estudiantes inclusivos en el sistema educativo regular. Se trata de un trabajo de investigación cualitativo comprendido en el diseño de estudio de casos. En este trabajo se entrevistó a tres personas directamente vinculadas con el estudio de caso llevado a cabo, el director de la institución educativa, la docente de aula y la madre de familia de la menor inclusiva, a través de las respuestas obtenidas por los entrevistados se pudo realizar el proceso de triangulación  basado en la descripción de los datos recopilados en las entrevistas a profundidad que permitieron llegar a la conclusión de que las aulas se hacen más justas cuando tanto directivos como docentes y padres de familia a través de un trabajo en equipo, consiguen acortar las distancias y brindar una educación en igualdad de condiciones para todos, teniendo como premisa el desarrollo de competencias y capacidades acordes al desarrollo individual de cada estudiante, evitando la exclusión en todas sus manifestaciones

    Autosuficiencia energética en la vivienda

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    Resumen Los edificios, junto al transporte suponen más de la mitad del consumo energético actual de combustible y de la contaminación a este asociada, de difícil solución por la dispersión de los procesos de combustión en poblaciones o carreteras. Esta distribución en la edificación de la demanda favorece el uso de energía solar, el recurso renovable más abundante y de fácil acceso sobre la superficie terrestre, especialmente adecuado en nuestro clima. El uso de tecnología solar requiere procesos de acumulación que garanticen la disponibilidad del calor excesivo del verano durante las frías noches de invierno así como la iluminación o las comunicaciones durante la noche en base a la radiación recibida en las horas de radiación solar. El trabajo describe la posibilidad de captura térmica en la cubierta con almacenamiento selectivo en el subsuelo capaz de satisfacer la demanda de energía para climatización de la vivienda a lo largo del año a un coste ,muy bajo. La energía eléctrica de "alta calidad" se genera y acumulé1localmente en forma de hidrógeno para alimentar según demanda mediante una pila de combustible. Con la tecnología actual, aún en pleno desarrollo, el balance es claramente positivo lo que significa la posibilidad de autosuficiencia energética para una parte considerable de las viviendas.El MEC ha financiado el desarrollo de nuevos dispositivos de hidrógeno en el proyecto "Diseño y realización de una nueva Pila de Combustible polimérica de bajo coste y alta eficacia" MCYT- ENE2005-09124-C04-02/ALT. y el CSIC ha financiado la generación de hidrógeno a partir de residuos orgánicos. El P.S.E. INVISO para industrialización de la vivienda sostenible financia el desarrollo integral de estos sistemas.Peer reviewe
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