13 resultados para nuclear spectroscopy
em Archivo Digital para la Docencia y la Investigación - Repositorio Institucional de la Universidad del País Vasco
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9 p. : il.
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5 p.
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"Click" chemistry has become an efficient avenue to unimolecular polymeric nanoparticles through the self-crosslinking of individual polymer chains containing appropriate functional groups. Herein we report the synthesis of ultra-small (7 nm in size) polymethyl methacrylate (PMMA) nanoparticles (NPs) by the "metal-free" cross-linking of PMMA-precursor chains prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization containing beta-ketoester functional groups. Intramolecular collapse was performed by the one-pot reaction of beta-ketoester moieties with alkyl diamines in tetrahydrofurane at r.t. (i.e., by enamine formation). The collapsing process was followed by size exclusion chromatography and by nuclear magnetic resonance spectroscopy. The size of the resulting PMMA-NPs was determined by dynamic light scattering. Enamine "click" chemistry increases the synthetic toolbox for the efficient synthesis of metal-free, ultra-small polymeric NPs.
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538 p.
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Introducción: La medición de la concentración de hierro hepática (CHH) por RM es una técnica no invasiva de gran utilidad en el diagnóstico de los pacientes con sospecha de sobrecarga férrica en hígado. Objetivo:Validar la eficacia de la RM 1 Tesla en la determinación de la (CHH) en pacientes con sospecha de sobrecarga férrica. Validar su capacidad para diagnosticar o descartar la presencia de una CHH sugestiva de hemocromatosis. Pacientes y métodos:Estudio observacional, transversal, con inclusión prospectiva de pacientes consecutivos. De 2002 a 2010 hemos obtenido la CHH estimada mediante RM 1 Tesla (método Gandon) y de RM 1,5 Tesla (método Alústiza), y mediante BH, en 56 pacientes consecutivos (58RM:35/23). Resultados:Grupo RM 1 Tesla: de acuerdo con CHH en BH, 15 pacientes clasificados como normales (<36µmol/g)-la RM valoró correctamente 7; sobreestimó 8-; 15 grupo hemosiderosis (36-80 µmol/g)-RM valoró correctamente 5, sobreestimó 10-; 5 grupo hemocromatosis (>80 µmol/g)-valoró correctamente las 5-. Existió una correlación entre la determinación de la CHH por BH y RM 1 Tesla con r=0.619. Existieron diferencias estadísticamente significativas (p<0.05) entre CHH media por biopsia (53.43/DE45.67/IC95%37.74 a 69.12) y por RM 1 Tesla (76.14/DE47.31/IC95% 60.46 a 92.97), con sobrevaloración por parte de la RM. Grupo RM 1,5 Tesla: de acuerdo con CHH en BH, normal en 14, hemosiderosis en 6 y hemocromatosis en 3. La RM valoró correctamente 6 y sobreestimó 8 en grupo normal; grupo hemosiderosis, 3 correctamente, 3 sobrevalorados; grupo hemocromatosis, valoró correctamente los 3. La correlación entre CHH por BH y RM 1,5 Tesla fue de r=0.815. La CHH media obtenida por BH (69,34/DE152.1/IC95% 3.57 a 135.1 ) y RM 1,5 Tesla (70.43/DE 57.63/IC95% 45.51 a 95.36) no demostraron diferencias significativas (p>0.05). Conclusiones: La determinación de CHH por RM 1 Tesla (método Gandon) es útil para diagnosticar o descartar hemocromatosis y para diagnosticar CHH normal. Existe una importante tendencia a la sobreestimación en pacientes sin y con sobrecarga férrica en la CHH obtenida por RM 1 Tesla. La determinación de CHH por RM 1,5 Tesla (método Alústiza) es superior a la de RM 1 Tesla, aunque también existe una tendencia a sobreestimar. La CHH media obtenida por BH o RM 1,5 Tesla no tuvieron diferencias significativas. En cambio si existieron entre BH y RM 1 Tesla.
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4 p.
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[ES]Este trabajo surge de la inquietud del alumno sobre la energía nuclear y mas concretamente sobre la energía de fusión. Esta inquietud se plasma en una recopilación de información sobre los combustibles necesarios , su abundancia y su forma de obtención actual. Analizaremos la posibilidad de implantar alguna de estas plantas de combustible en el País Vasco, junto con un estudio de una posible central nuclear de fusión con la suma de la potencia de cada uno de los reactores de fisión que se encuentran actualmente en funcionamiento en el estado Español. Compararemos las cantidades de combustible necesarias en un año de uranio y el combustible de fusión, así como el coste de construcción de cada una.
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EN]This is a document done to try to see the effect of a nuclear power plant accident. In particular, it studies what would be the radiation doses delivered to the people in the close areas around the power plant of Garoña, if it had suffered from a loss of coolant accident during its normal functioning.
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Lipoproteins are responsible for cholesterol traffic in humans. Low density lipoprotein (LDL) delivers cholesterol from liver to peripheral tissues. A misleading delivery can lead to the formation of atherosclerotic plaques. LDL has a single protein, apoB-100, that binds to a specific receptor. It is known that the failure associated with a deficient protein-receptor binding leads to plaque formation. ApoB-100 is a large single lipid-associated polypeptide difficulting the study of its structure. IR spectroscopy is a technique suitable to follow the different conformational changes produced in apoB-100 because it is not affected by the size of the protein or the turbidity of the sample. We have analyzed LDL spectra of different individuals and shown that, even if there are not big structural changes, a different pattern in the intensity of the band located around 1617 cm 21 related with strands embedded in the lipid monolayer, can be associated with a different conformational rearrangement that could affect to a protein interacting region with the receptor.
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In the present study we have investigated the population genetic structure of albacore (Thunnus alalunga, Bonnaterre 1788) and assessed the loss of genetic diversity, likely due to overfishing, of albacore population in the North Atlantic Ocean. For this purpose, 1,331 individuals from 26 worldwide locations were analyzed by genotyping 75 novel nuclear SNPs. Our results indicated the existence of four genetically homogeneous populations delimited within the Mediterranean Sea, the Atlantic Ocean, the Indian Ocean and the Pacific Ocean. Current definition of stocks allows the sustainable management of albacore since no stock includes more than one genetic entity. In addition, short-and long-term effective population sizes were estimated for the North Atlantic Ocean albacore population, and results showed no historical decline for this population. Therefore, the genetic diversity and, consequently, the adaptive potential of this population have not been significantly affected by overfishing.
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[EN] In the recent years a series of optical correlation techniques have been developed in order to be able to measure flow velocity with high spatial resolution while being non-invasive in order to be employed in-vivo on biological organisms. The technique employed in my thesis work, scanning laser image correlation (SLIC), is a powerful approach for the detection of flow motions because it overcomes some limitations of the classical spectroscopy techniques. SLIC method consists in repeated laser scans over a linear pattern and on the cross correlation of the signal emitted by the excited fluorophores in different positions along the scan line. Therefore, the resulting measurements for flow velocity are really accurate.
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One of the main problems of fusion energy is to achieve longer pulse duration by avoiding the premature reaction decay due to plasma instabilities. The control of the plasma inductance arises as an essential tool for the successful operation of tokamak fusion reactors in order to overcome stability issues as well as the new challenges specific to advanced scenarios operation. In this sense, given that advanced tokamaks will suffer from limited power available from noninductive current drive actuators, the transformer primary coil could assist in reducing the power requirements of the noninductive current drive sources needed for current profile control. Therefore, tokamak operation may benefit from advanced control laws beyond the traditionally used PID schemes by reducing instabilities while guaranteeing the tokamak integrity. In this paper, a novel model predictive control (MPC) scheme has been developed and successfully employed to optimize both current and internal inductance of the plasma, which influences the L-H transition timing, the density peaking, and pedestal pressure. Results show that the internal inductance and current profiles can be adequately controlled while maintaining the minimal control action required in tokamak operation.