2,019 research outputs found

    Efecto de la melatonina y análogos sobre la respuesta de la secreción lagrimal

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    Actualmente la mayoría de los tratamientos en la enfermedad de ojo seco son paliativos y se restringe al uso de colirios y lágrimas artificiales que mejoran la sintomatología del paciente. Una de las nuevas estrategias terapéuticas se centra en buscar compuestos que tengan el efecto de potenciar la secreción lagrimal. En este contexto se han desarrollado y comercializado sustancias de uso tópico con efecto secretagogo lagrimal como el Rebamipide y el Diquafosol, y se han descrito otras que muestran esta capacidad a nivel experimental. Una de ellas es la melatonina. Las evidencias de la síntesis de esta neurohormona en las glándulas lagrimales, su presencia en la secreción lagrimal, su efecto estimulador sobre la producción de lágrima combinado con el dinucleótido Ap4A, nos hizo plantearnos la posibilidad de que la melatonina tuviera un efecto secretagogo de forma aislada, así como sus análogos agomelatina, 5-MCA-NAT e IIK7.Entre los objetivos que persigue esta tesis está estudiar in vivo (en conejos)la capacidad de aumentar la secreción lagrimal de la melatonina y estos tres análogos, así como dilucidar las vías de actuación a través de las que se realiza dicha acción. Es decir, la implicación en el efecto secretagogo de los diferentes receptores de membrana específicos de melatonina o MTr (MT1, MT2 y MT3/QR2)presentes en la superficie ocular y glándulas lagrimales..

    Thermal behavior of calafate (Berberis buxifolia) seeds

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    Low temperature is the most important factor limiting the distribution of plants. In this study the low temperature thermal behavior of calafate seeds was analyzed by Differential Scanning Calorimetry (DSC), and a vibrational characterization of their different components was conducted by infrared spectroscopy (FTIR). In cold-acclimated plants, such as calafate, the total percentage of polyunsaturated fatty acids in their seeds is significantly higher than that of saturated fatty acids. Successive freezing-thawing cycles lead to increased formation of linoleic (LA) and linolenic (LNA) a-crystals. This process would barely modify the phase-transition temperature of the lipid membrane but would lead to an increase in the membrane fluidity (LNA would make the cell membranes more fluid during seed development). It seems that processes in membranes rather than in the glassy cytoplasm may determine the cooling resistance

    Captura de movimiento del alumnado: una aproximación

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    Gracias a las nuevas tecnologías se ha conseguido contribuir a grandes avances en la ciencia y en la medicina, hacer intervenciones quirúrgicas menos invasivas, mejorar sustancialmente la calidad de vida de personas con necesidades especiales mediante aplicaciones específicas, ser mucho más precisos en el diagnóstico de trastornos y enfermedades e incluso la construcción de dispositivos que permitan a personas con algunas discapacidades físicas realizar acciones que de otra forma les hubieran resultado imposible. La tecnología no es incumbencia exclusiva de los tecnólogos. Éstos desarrollan las herramientas pero el verdadero sentido se adquiere con su uso, con su aplicación... Y precisamente esto es lo que nos ha llamado la atención a la hora de plantear este proyecto: cómo podemos aplicar las nuevas tecnologías para capturar y analizar el movimiento de los estudiantes y posteriormente buscar patrones de movimiento asociados a sus resultados académicos

    Vibrational and thermal characterization of seeds, pulp, leaves and seed oil of Rosa rubiginosa

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    Rosa rubiginosa L. seed oil has been studied for its application in skin care products, but the chemical nature of seeds, pulp and even leaves, apart from that of oil, is also relevant with a view to the application of this weed for biodiesel production. All these vegetal materials were studied by infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) for characterisation purposes. FTIR bands at 3005, 2924, 1740, 1654 and 1456 cm-1 were used to estimate the iodine index, suitable for biofuels, and the oxidation stability degree. From the viewpoint of the thermal stability, both the seed oil (for which pyrolysis occurs at 462°C), the raw seeds and the rosehip pulp (with decomposition temperatures of 373°C and 333°C, respectively) showed potential as a biomass feedstock for conversion into biofuels. Caracterización térmica y vibracional de las semillas, pulpa, hojas y aceite de semillas de Rosa rubiginosa. El aceite de semillas de R. rubiginosa L. ha sido estudiado para su aplicación en productos para el cuidado de la piel, pero la naturaleza química de las semillas, pulpa y hojas, además de la del aceite, también es importante con miras a la aplicación de esta mala hierba para la producción de biodiesel. Los materiales vegetales mencionados se han estudiado mediante espectroscopía infrarroja (FTIR) y calorimetría diferencial de barrido (DSC) con fines de caracterización. Las bandas del espectro infrarrojo en 3005, 2924, 1740, 1654 y 1456 cm-1 han sido utilizadas para estimar el índice de yodo, adecuado para los biocombustibles, y el grado de estabilidad a la oxidación. Desde el punto de vista de la estabilidad térmica, tanto el aceite de semillas (para el que la pirólisis se produce a 462ºC) como las semillas crudas y la pulpa (con temperaturas de descomposición de 373°C y 333°C, respectivamente) mostraron potencial como materia prima de biomasa para su conversión en biocombustibles

    Geometric Algebra Framework Applied to Symmetrical Balanced Three-Phase Systems for Sinusoidal and Non-Sinusoidal Voltage Supply

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    This paper presents a new framework based on geometric algebra (GA) to solve and analyse three-phase balanced electrical circuits under sinusoidal and non-sinusoidal conditions. The proposed approach is an exploratory application of the geometric algebra power theory (GAPoT) to multiple-phase systems. A definition of geometric apparent power for three-phase systems, that complies with the energy conservation principle, is also introduced. Power calculations are performed in a multi-dimensional Euclidean space where cross effects between voltage and current harmonics are taken into consideration. By using the proposed framework, the current can be easily geometrically decomposed into active- and non-active components for current compensation purposes. The paper includes detailed examples in which electrical circuits are solved and the results are analysed. This work is a first step towards a more advanced polyphase proposal that can be applied to systems under real operation conditions, where unbalance and asymmetry is considered

    Vector Geometric Algebra in Power Systems: An Updated Formulation of Apparent Power under Non-Sinusoidal Conditions

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    Traditional electrical power theories and one of their most important concepts—apparent power—are still a source of debate, because they present several flaws that misinterpret the power-transfer and energy-balance phenomena under distorted grid conditions. In recent years, advanced mathematical tools such as geometric algebra (GA) have been introduced to address these issues. However, the application of GA to electrical circuits requires more consensus, improvements and refinement. In this paper, electrical power theories for single-phase systems based on GA were revisited. Several drawbacks and inconsistencies of previous works were identified, and some amendments were introduced. An alternative expression is presented for the electric power in the geometric domain. Its norm is compatible with the traditional apparent power defined as the product of the RMS voltage and current. The use of this expression simplifies calculations such as those required for current decomposition. This proposal is valid even for distorted currents and voltages. Concepts are presented in a simple way so that a strong background on GA is not required. The paper included some examples and experimental results in which measurements from a utility supply were analysed

    Monitoring and preliminary analysis of the natural responses recorded in a poorly accessible streambed spring located at a fluviokarstic gorge in Southern Spain

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    The analysis of natural responses (hydrodynamic, hydrothermal and hydrochemical) of karst springs is a well-established approach to provide insights into the hydrogeological functioning of the aquifers that they drain. However, a suitable monitoring program of these responses are often difficult to launch in poorly accessible streambed springs, due to the mixing between surface water and groundwater, in addition to topographic impediments. This work describes the installation procedure of the measurement equipment and the preliminary hydrogeological dataset collected at the Charco del Moro spring (Southern Spain) during one year. This outlet emerges 5 m below water surface, at the bottom of a partially flooded 20 - 200 m deep and 2 km long gorge, eroded by the Guadiaro River streamflow. It is considered the largest discharge point in the region, draining groundwater from northern nearby carbonate outcrops, although its catchment area is not established yet. Continuous (hourly) monitoring of electrical conductivity, water temperature, turbidity and water level (discharge) reflects a high degree of heterogeneity in the duality of groundwater flow and storage dynamics, which is typical of karst conduit flow systemsUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

    Seasonal and sex-related variations in serum steroid hormone levels in wild and farmed brown trout Salmo trutta L. in the north-west of Spain

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    P. 720-728Serum steroid profiles were investigated in order to evaluate the potential use of circulating sex steroid levels as a tool for sex identification in brown trout. Changes in the serum concentrations of testosterone (T), progesterone (P), 17-β-estradiol (E2), and cortisol (F) in wild and farmed mature female and male brown trout, Salmo trutta L., were measured in each season (January, May, July, and October) in six rivers and four hatcheries located in the north-west of Spain. Serum cortisol levels in farmed brown trout were significantly higher and showed a seasonal pattern opposite to that found in wild trout. Because levels of the hormones under study can be affected by disruptive factors such as exposure to phytoestrogens (which alters the hypothalamic–pituitary–gonadal axis) and infection with Saprolegnia (which alters the hypothalamic–pituitary–adrenal axis), both factors are taken into account.S

    Ambient Intelligence Systems for Personalized Sport Training

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    Several research programs are tackling the use of Wireless Sensor Networks (WSN) at specific fields, such as e-Health, e-Inclusion or e-Sport. This is the case of the project “Ambient Intelligence Systems Support for Athletes with Specific Profiles”, which intends to assist athletes in their training. In this paper, the main developments and outcomes from this project are described. The architecture of the system comprises a WSN deployed in the training area which provides communication with athletes’ mobile equipments, performs location tasks, and harvests environmental data (wind speed, temperature, etc.). Athletes are equipped with a monitoring unit which obtains data from their training (pulse, speed, etc.). Besides, a decision engine combines these real-time data together with static information about the training field, and from the athlete, to direct athletes’ training to fulfill some specific goal. A prototype is presented in this work for a cross country running scenario, where the objective is to maintain the heart rate (HR) of the runner in a target range. For each track, the environmental conditions (temperature of the next track), the current athlete condition (HR), and the intrinsic difficulty of the track (slopes) influence the performance of the athlete. The decision engine, implemented by means of (m; s)-splines interpolation, estimates the future HR and selects the best track in each fork of the circuit. This method achieves a success ratio in the order of 80%. Indeed, results demonstrate that if environmental information is not take into account to derive training orders, the success ratio is reduced notably.Ministerio de Educación y Ciencia; DEP2006-56158-C03-01/02/03Ministerio de Educación y Ciencia; TEC2007-67966 -01/02/TCM CON-PARTE-1/2Ministerio de Industria, Turismo y Comercio ; TSI-020301-2008-16 ELISAMinisterio de Industria, Turismo y Comercio ; TSI-020301-2008-2 PIRAmID
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