995 resultados para Voltage source converter (VSC)


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En aquest treball es proposa una aproximació al món del codi font obert des del punt de vista de la realització de portals col·laboratius i les seves eines involucrades. Per fer-ho, es passa revista als diferents tipus d'aplicacions, plataformes i utilitats que trobem disponibles, i s'agrupen en diferents categories: infraestructura i sistemes, serveis de comunicació, serveis de comunitat, serveis genèrics de portal, eines d'interacció amb sistemes mòbils, eines per al desenvolupament i prova i llibreries de suport.

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Le fonctionnement du système nerveux est sensible aux variations de la concentration d'acide. Une acidification des tissus peut se produire pendant une activité neuronale intense ou dans des situations physiopathologiques telles que l'inflammation ou les lésions cérébrales. Les canaux ioniques sensibles à l'acide (ASIC) sont activés par acidification et jouent un rôle important dans la détection des changements d'acide. Les ASICs contribuent à la dégénérescence neuronale après une lésion cérébrale, puisque leur inhibition limite la lésion neuronale. L'acidification induite par une inflammation du tissu nerveux conduit à des stimuli de douleur, qui sont détectés par ces canaux. En effet, les toxines qui bloquent spécifiquement les ASICs montrent des effets analgésiques dans des modèles animaux. La structure 3D d'ASIC peut être comparée à une main qui tient une boule entre son pouce et le doigt. Les différents domaines d'ASIC sont appelés doigt, pouce, jointure, boule-ß et paume. Les domaines transmembranaires représentent le poignet de cette main. Mon projet de thèse vise à décrire les mouvements survenant sur ce canal pendant son activité. A cet effet, j'ai utilisé une technique combinée qui permet la mesure des mouvements en temps réel durant l'activité du canal. J'ai montré les réarrangements des domaines extracellulaires pendant l'activité ASIC. Ces mouvements sont transmis au pore du canal, ou ils contrôlent sa fermeture et ouverture. La direction de ces mouvements a été évaluée pour les domaines doigt et jointure, et nous avons montré qu'ils s'éloignent de la boule-ß lors de l'acidification. J'ai également été en mesure de décrire les mouvements qui se produisent dans la poche acidique, une zone qui est considérée comme importante, car elle représente le site de liaison de certaines toxines de venin qui agissent sur les ASICs. J'ai ainsi pu montrer que les domaines doigt et le pouce qui forment la poche acidique se rapprochent l'un de l'autre pendant l'activation du canal. Ces résultats sont en accord avec des observations précédentes réalisées sur les ASICs par d'autres chercheurs. Enfin, cette analyse approfondie permet d'améliorer les connaissances sur le contrôle de l'activité ASIC; de plus, les mécanismes trouvés ici sont probablement partagés entre les canaux de la famille à laquelle appartiennent les ASICs. -- Les acid-sensing ion channels (ASICs) sont des canaux sodiques ouverts par les protons et principalement exprimés dans le système nerveux. Ils sont impliqués dans la détection des protons dans de nombreux états physiologiques et pathologiques comme l'ischémie et la perception de la douleur. La structure cristalline de l'isoforme ASIC1 de poulet a été déterminée dans l'état désensibilisé et ouvert. Les études fonctionnelles indiquent que la protonation des résidus clés dans la boucle extracellulaire déclenche des changements de conformation conduisant à l'ouverture du canal. Cependant, les mécanismes moléculaires qui relient la protonation à l'ouverture et la fermeture du canal n'ont pas encore été clarifiés. Dans cette étude, nous avons utilisé la voltage-clamp fluorimétrie (VCF) pour révéler les mouvements de l'activité associée qui se produisent dans les différents domaines de l'ASICla. Les fluorophores positionnés dans le pouce, la paume, le doigt, l'articulation et dans les domaines de l'entrée du pore extracellulaire ont montré des signaux de VCF liés à des changements de conformation au cours de l'activité du canal. La synchronisation des changements de fluorescence indique une séquence complexe de mouvements en fonction du pH. La cinétique de la fluorescence et des signaux de courant ont été comparés les uns aux autres afin de déterminer si le mouvement détecté par le signal de fluorescence correspond à une transition fonctionnelle définie du canal. Certains des résidus testés se sont révélés être étroitement liés à la désensibilisation du canal ou au rétablissement après la désensibilisation. En outre, nous avons trouvé qu'un tryptophane endogène de la boule-ß diminue le signal de fluorescence des sondes positionnées dans les domaines doigt et jointure. L'augmentation observée de ces signaux indique que ces domaines s'éloignent à une distance à partir de la boucle de la boule-ß. Sur la base de ce principe, nous avons généré des paires Trp-Cys « quencher», dans lequel le Cys est utilisé comme site d'ancrage pour attacher le fluorophore. Ensuite, nous avons évalué les changements de conformation qui se produisent au niveau de la poche acide, une zone importante pour la fonction et la régulation d'ASIC. Les signaux de fluorescence indiquent un mouvement de l'hélice supérieure du pouce vers le doigt et une rotation de la boule-ß dans le sens horaire. L'analyse de la cinétique indique que les mouvements des sous-domaines qui composent la poche acide se produisent pendant la désensibilisation du canal. Mon projet de doctorat représente la première analyse approfondie des changements conformationnels dépendants de l'activité des ASICs et fournit des informations sur les mécanismes de contrôle de l'activité du canal qui sont probablement partagés avec d'autres canaux proches.

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The modern approach to the development of new chemical entities against complex diseases, especially the neglected endemic diseases such as tuberculosis and malaria, is based on the use of defined molecular targets. Among the advantages, this approach allows (i) the search and identification of lead compounds with defined molecular mechanisms against a defined target (e.g. enzymes from defined pathways), (ii) the analysis of a great number of compounds with a favorable cost/benefit ratio, (iii) the development even in the initial stages of compounds with selective toxicity (the fundamental principle of chemotherapy), (iv) the evaluation of plant extracts as well as of pure substances. The current use of such technology, unfortunately, is concentrated in developed countries, especially in the big pharma. This fact contributes in a significant way to hamper the development of innovative new compounds to treat neglected diseases. The large biodiversity within the territory of Brazil puts the country in a strategic position to develop the rational and sustained exploration of new metabolites of therapeutic value. The extension of the country covers a wide range of climates, soil types, and altitudes, providing a unique set of selective pressures for the adaptation of plant life in these scenarios. Chemical diversity is also driven by these forces, in an attempt to best fit the plant communities to the particular abiotic stresses, fauna, and microbes that co-exist with them. Certain areas of vegetation (Amazonian Forest, Atlantic Forest, Araucaria Forest, Cerrado-Brazilian Savanna, and Caatinga) are rich in species and types of environments to be used to search for natural compounds active against tuberculosis, malaria, and chronic-degenerative diseases. The present review describes some strategies to search for natural compounds, whose choice can be based on ethnobotanical and chemotaxonomical studies, and screen for their ability to bind to immobilized drug targets and to inhibit their activities. Molecular cloning, gene knockout, protein expression and purification, N-terminal sequencing, and mass spectrometry are the methods of choice to provide homogeneous drug targets for immobilization by optimized chemical reactions. Plant extract preparations, fractionation of promising plant extracts, propagation protocols and definition of in planta studies to maximize product yield of plant species producing active compounds have to be performed to provide a continuing supply of bioactive materials. Chemical characterization of natural compounds, determination of mode of action by kinetics and other spectroscopic methods (MS, X-ray, NMR), as well as in vitro and in vivo biological assays, chemical derivatization, and structure-activity relationships have to be carried out to provide a thorough knowledge on which to base the search for natural compounds or their derivatives with biological activity.

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This paper focuses on likelihood ratio based evaluations of fibre evidence in cases in which there is uncertainty about whether or not the reference item available for analysis - that is, an item typically taken from the suspect or seized at his home - is the item actually worn at the time of the offence. A likelihood ratio approach is proposed that, for situations in which certain categorical assumptions can be made about additionally introduced parameters, converges to formula described in existing literature. The properties of the proposed likelihood ratio approach are analysed through sensitivity analyses and discussed with respect to possible argumentative implications that arise in practice.

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BACKGROUND: Mutations in the SCN9A gene cause chronic pain and pain insensitivity syndromes. We aimed to study clinical, genetic, and electrophysiological features of paroxysmal extreme pain disorder (PEPD) caused by a novel SCN9A mutation. METHODS: Description of a 4-generation family suffering from PEPD with clinical, genetic and electrophysiological studies including patch clamp experiments assessing response to drug and temperature. RESULTS: The family was clinically comparable to those reported previously with the exception of a favorable effect of cold exposure and a lack of drug efficacy including with carbamazepine, a proposed treatment for PEPD. A novel p.L1612P mutation in the Nav1.7 voltage-gated sodium channel was found in the four affected family members tested. Electrophysiologically the mutation substantially depolarized the steady-state inactivation curve (V1/2 from -61.8 ± 4.5 mV to -30.9 ± 2.2 mV, n = 4 and 7, P < 0.001), significantly increased ramp current (from 1.8% to 3.4%, n = 10 and 12) and shortened recovery from inactivation (from 7.2 ± 5.6 ms to 2.2 ± 1.5 ms, n = 11 and 10). However, there was no persistent current. Cold exposure reduced peak current and prolonged recovery from inactivation in wild-type and mutated channels. Amitriptyline only slightly corrected the steady-state inactivation shift of the mutated channel, which is consistent with the lack of clinical benefit. CONCLUSIONS: The novel p.L1612P Nav1.7 mutation expands the PEPD spectrum with a unique combination of clinical symptoms and electrophysiological properties. Symptoms are partially responsive to temperature but not to drug therapy. In vitro trials of sodium channel blockers or temperature dependence might help predict treatment efficacy in PEPD.

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BACKGROUND AND PURPOSE: A new clinical construct termed embolic stroke of undetermined source (ESUS) was recently introduced, but no such population has been described yet. Our aim is to provide a detailed descriptive analysis of an ESUS population derived from a large prospective ischemic stroke registry using the proposed diagnostic criteria. METHODS: The criteria proposed by the Cryptogenic Stroke/ESUS International Working Group were applied to the Athens Stroke Registry to identify all ESUS patients. ESUS was defined as a radiologically confirmed nonlacunar brain infarct in the absence of (a) extracranial or intracranial atherosclerosis causing ≥50% luminal stenosis in arteries supplying the ischemic area, (b) major-risk cardioembolic source, and (c) any other specific cause of stroke. RESULTS: Among 2735 patients admitted between 1992 and 2011, 275 (10.0%) were classified as ESUS. In the majority of ESUS (74.2%), symptoms were maximal at onset. ESUS were of moderate severity (median National Institute Health Stroke Scale score, 5). The most prevalent risk factor was arterial hypertension (64.7%), and 50.9% of patients were dyslipidemic. Among potential causes of the ESUS, covert atrial fibrillation (AF) was the most prevalent: in 30 (10.9%) patients, AF was diagnosed during hospitalization for stroke recurrence, whereas in 50 (18.2%) patients AF was detected after repeated ECG monitoring during follow-up. Also, covert AF was strongly suggested in 38 patients (13.8%) but never recorded. CONCLUSIONS: About 10% of patients with first-ever ischemic stroke met criteria for ESUS; covert paroxysmal AF seems to be a frequent cause of ESUS.

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Purpose: EEG is mandatory in the diagnosis of the epilepsy syndrome. However, its potential as imaging tool is still under estimated. In the present study, we aim to determine the prerequisites of maximal benefit of electric source imaging (ESI) to localize the irritative zone in patients with focal epilepsy. Methods: One hundred fifty patients suffering from focal epilepsy and with minimum 1 year postoperative follow-up were studied prospectively and blinded to the underlying diagnosis. We evaluated the influence of two important factors on sensitivity and specificity of ESI: the number of electrodes (low resolution, LR-ESI: <30 versus high resolution, HR-ESI: 128-256 electrodes), and the use of individual MRI (i-MRI) versus template MRI (t-MRI) as the head model. Findings: ESI had a sensitivity of 85% and a specificity of 87% when HR-ESI with i-MRI was used. Using LR-ESI, sensitivity decreased to 68%, or even 57% when only t-MRI was available. The sensitivity of HR-ESI/i-MRI compared favorably with those of MRI (76%), PET (69%) and ictal/interictal SPECT (64%). Interpretation: This study on a large patient group shows excellent sensitivity and specificity of ESI if 128 EEG channels or more are used for ESI and if the results are coregistered to the patient's individual MRI. Localization precision is as high as or even higher than established brain imagery techniques. HR-ESI appears to be a valuable additional imaging tool, given that larger electrode arrays are easily and rapidly applied with modern EEG equipment and that structural MRI is nearly always available for these patients.

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Desplegar una solución fiable, potente y escalable de correo electrónico, en combinación de un entorno colaborativo de aplicaciones, bajo el apadrinamiento de software open source.

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Elaboración de un plan de empresa para Most Servicios Informáticos S.L. para el desarrollo de nuevas líneas de negocio basadas en soluciones Open Source.

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El presente documento tiene por objetivo identificar la evolución que ha tenido la inteligencia de negocios en la ultima década, para determinar en que punto se encuentra y para donde va, además de identificar las alternativas de desarrollo que tiene, apalancándose con las Tecnologías de la Información, y más específicamente con las herramientas empaquetadas de BI de tipo Open Source.Así mismo, la presente investigación identifica las prácticas más convenientes, para sistematizar la elección y adaptación de la inteligencia de negocios en las organizaciones, analizando estas en uncaso exitoso real de implantación de la inteligencia de negocios sobre una herramienta BI tipo Open Source.

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Natural products have long been providing important drug leads for infectious diseases. Leishmaniasis is a protozoan parasitic disease found mainly in developing countries, and it has toxic therapies with few alternatives. Fungal infections have been the main cause of death in immunocompromised patients and new drugs are urgently needed. In this work, a total of 16 plant species belonging to 11 families, selected on an ethnopharmacological basis, were analyzed in vitro against Leishmania (L.) chagasi, Leishmania (L.) amazonensis, Candida krusei, and C. parapsilosis. Of these plant species, seven showed antifungal activity against C. krusei, five showed antileishmanial activity against L. chagasi and four against L. amazonensis, among them species of genus Plectranthus. Our findings confirm the traditional therapeutic use of these plants in the treatment of infectious and inflammatory disorders and also offer insights into the isolation of active and novel drug prototypes, especially those used against neglected diseases as Leishmaniasis.

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This case study introduces our continuous work to enhance the virtual classroom in order to provide faculty and students with an environment open to their needs, compliant with learning standards and, therefore compatible with other e-learning environments, and based on open source software. The result is a modulable, sustainable and interoperable learning environment that can be adapted to different teaching and learning situations by incorporating the LMS integrated tools as well as wikis, blogs, forums and Moodle activities among others.

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The Internet is a fundamental part of the daily life of adolescents, they consider it as a safe and confidential source of information on health matters. The aims is to describe the experience of Spanish adolescents searching for health information on the Internet. Methods A cross-sectional study of 811 school-age adolescents in Granada was carried out. An adapted and piloted questionnaire was used which was controlled by trained personnel. Sociodemographic and health variables were included together with those concerning the conditions governing access to and use of information and communication technologies (ICT). Results 811 adolescents were surveyed (99.38% response rate), mean age was 17 years old. Of these, 88% used the Internet; 57.5% used it on a daily or weekly basis and 38.7% used it occasionally. Nearly half the sample group (55.7%) stated that they used the Internet to search for health-related information. The main problems reported in the search for e-health were the ignorance of good web pages (54.8%) and the lack of confidence or search skills (23.2%). Conclusions In conclusion, it seems plausible to claim that websites designed and managed by health services should have a predominant position among interventions specifically addressed to young people.

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Background. The use of hospital discharge administrative data (HDAD) has been recommended for automating, improving, even substituting, population-based cancer registries. The frequency of false positive and false negative cases recommends local validation. Methods. The aim of this study was to detect newly diagnosed, false positive and false negative cases of cancer from hospital discharge claims, using four Spanish population-based cancer registries as the gold standard. Prostate cancer was used as a case study. Results. A total of 2286 incident cases of prostate cancer registered in 2000 were used for validation. In the most sensitive algorithm (that using five diagnostic codes), estimates for Sensitivity ranged from 14.5% (CI95% 10.3-19.6) to 45.7% (CI95% 41.4-50.1). In the most predictive algorithm (that using five diagnostic and five surgical codes) Positive Predictive Value estimates ranged from 55.9% (CI95% 42.4-68.8) to 74.3% (CI95% 67.0-80.6). The most frequent reason for false positive cases was the number of prevalent cases inadequately considered as newly diagnosed cancers, ranging from 61.1% to 82.3% of false positive cases. The most frequent reason for false negative cases was related to the number of cases not attended in hospital settings. In this case, figures ranged from 34.4% to 69.7% of false negative cases, in the most predictive algorithm. Conclusions. HDAD might be a helpful tool for cancer registries to reach their goals. The findings suggest that, for automating cancer registries, algorithms combining diagnoses and procedures are the best option. However, for cancer surveillance purposes, in those cancers like prostate cancer in which care is not only hospital-based, combining inpatient and outpatient information will be required.