En el presente trabajo se proponen mecanismos para varias reacciones que conducen a la formación de productos de glicación avanzada, en base a cálculos realizados a nivel PBE/GGA, en el contexto de la teoría del funcional de la densidad (DFT), en un modelo de una capa de fosfolípidos diseñada bajo condiciones periódicas de contorno. En los modelos periódicos usados, cada celda unidad contiene dos moléculas de fosfatidiletanolamina (PE), moléculas reactivas adicionales según sea la reacción estudiada, y un número suficiente de moléculas de agua para formar una red de enlaces de hidrógeno sobre la superficie aminofosfolipídica. Estas redes de enlaces de hidrógeno fueron importantes para la estabilización de los reactivos, intermedios, productos y estados de transición de las reacciones estudiadas, participando algunas moléculas de agua de estas redes, como puentes para las transferencias de protones entre los grupos reactivos. Las reacciones estudiadas comprendieron la formación de bases de Schiff a partir de acetaldehído y PE, el reordenamiento de Amadori teniendo como reactivo de partida una base Schiff de D-eritrosa-PE, la descomposición del peróxido de hidrógeno y la formación de carboximetil-PE a partir de glioxal y PE. En las reacciones en las que se presenta un paso de deshidratación, este fue el paso limitante, lo que es consistente con la evidencia experimental disponible sobre las mismas. En el estudio de todas las reacciones estudiadas destaca el rol catalítico de las capas de PE sobre las reacciones que acontecen en su superficie Este efecto catalítico se realiza a través a través de componentes de la superficie de PE, como los grupos amino y grupos fosfato que forman parte la red de enlaces de hidrógeno, estabilizando la misma y facilitando la acumulación de moléculas de agua en su proximidad. En algunas reacciones estudiadas, los grupos amino de la PE participan como grupos donantes o aceptores en las transferencias de protones. Basados en nuestros resultados, es posible plantear la hipótesis de que la superficie de las membranas de fosfolípidos pueden modificar el comportamiento cinético de algunas reacciones biológicas que acontecen sobre la misma, actuando como catalizadores. / Mechanisms for the formation of advanced glycation end-products on an amine-phospholipid monolayer model were realized by using density functional theory (DFT) calculations carried out at the PBE/GGA level under periodic boundary conditions. Each unit cell contained two phosphatidylethanolamine (PE) molecules, and a sufficient number of water molecules for forming hydrogen bond networks. These networks were involved in the reactions, stabilizing reactants, intermediates, products and transition states and performing as proton-transfer carriers, important in all steps of reactions. The studied reactions covered formation of Schiff bases, having acetaldehyde as carbonyl compound, the Amadori rearrangement since Schiff base from D-erythrose and PE, the hydrogen peroxide decomposition above PE surface, and the formation of carboxymethylated-PE from glyoxal and PE. In the studied reactions where there is a dehydration step, it was the limiting step, which is consistent with the experimental evidence available for such reactions. The most important outcome of our study is highlighting the catalytic role of PE-surface on the studied reactions which proceed on it. This catalytic effect is realized through PE-surface components as amine groups and phosphate groups which might enhance reaction forming hydrogen bonds with water molecules of the hydrogen bond network, and facilitating the water molecules accumulation in the proximity of the PE-surface, amine groups could participate additionally as donors or acceptors in the proton transfers. Based in our results, it is possible to hypothesize that cell membrane phospholipids surface environment modify the kinetic behavior of some biological reactions, being capable of catalyzing them.

La present tesi esta focalitzada tant en la síntesi de molècules orgàniques òpticament actives així com en la seva aplicació i caracterització en dispositius fotovoltaics, concretament per a les cel·les solars sensibilitzades amb colorant (DSSC en anglès). Les DSSC són cel·les foto-electroquímiques formades per colorant ancorat a un semiconductor (normalment TiO2) i en presencia d'un electròlit. En aquests dispositius, cada component té un efecte clau en la eficiència final de la cel·la, degut als processos de transferència electrònica que tenen lloc la interfície TiO2/colorant/electròlit. Aquests processos varen ser estudiat en gran detall utilitzant porfirines, perilens i D -  - A com a colorants, per poder així definir uns paràmetres amb els quals l'eficiència final del dispositiu es pugui correlacionar amb l'estructura molecular del colorant. Entendre aquesta relació entre l'estructura química i l'eficiència del dispositiu permet un millor diseny de futures molecules per a DSSC. / The present thesis focuses on the synthesis of organic chromophores as well as their use in optoelectronic devices, particulary in Dye Sensitized Solar Cells (DSSC). This kind of solar cell is based on a photoactive unit, a dye, anchored to a nanostructured metal-oxide semiconductor, usually TiO2, in a redox electrolyte media and sandwiched between two contact electrodes. In DSSC devices, each component (semiconductor, sensitizer and electrolyte) plays an important role in determining the final device efficiency, in a large part due to the charge transfer processes that take place at the TiO2/dye/electrolyte interface. Therefore, these charge transfer kinetics were studied using porphyrins, perylenes and donor -  - acceptor organic dyes in order to understand and establish a relationship between the molecular structure and the device performance. Improved understanding of this relationship is crucial for improved molecular design of future dyes for DSSC.

La reproduction dans des mammifères est réglée par les neurones qui synthétisent et sécrètent l'hormone de gonadotropin-sortie (GnRH) et à travers l'espèce ces neurones sont présents dans peu de nombres dispersés dans l'hypothalamus. En raison de limité neurogenesis de ceux des types cellulaires neuronaux à l'extérieur du cerveau dans placode olfactif, ces neurones sont soumis au règlement serré pendant le développement embryonnaire pour atteindre leurs objectifs finaux dans l'hypothalamus, de la naissance jusqu'à la puberté pour la sécrétion minimale d'hormone et pendant des adultes pour réaliser la sécrétion pulsatile de l'hormone. La dérégulation dans n'importe lequel de ces mécanismes peut mener aux effets délétères sur la reproduction adulte et des pathologies cliniques comme l'absence de puberté, hypogonadism, la stérilité, l'aménorrhée, etc. Kallmann syndrome (KS), un d'entre ceux sévères (graves) reproducteur / Reproduction in mammals is regulated by neurons that synthesize and secrete gonadotropin-releasing hormone (GnRH) and across the species these neurons are present in few numbers scattered in the hypothalamus. Due to limited neurogenesis of these neuronal cell types outside the brain in the olfactory placode, these neurons are subjected to tight regulation during embryonic development to reach their final targets in the hypothalamus, from birth until puberty for minimal secretion of hormone and during adults to achieve pulsatile secretion of the hormone. Deregulation in any of these mechanisms may lead to deleterious effects on adult reproduction and clinical pathologies like absence of puberty, hypogonadism, sterility, amenorrhea, etc. Kallmann syndrome (KS), one of these severe reproductive pathologies is an inherited disorder and patients affected with this syndrome display anosmia (inability to smell) and hypogonadotropic hypogonadism (HH). Genetic screening of molecules in these patients lead to identification of genes like KAL1, FGFR1, FGF8, PROK2, PROKR2, WDR11 and CHD7 encoding proteins that play an important role in migration and targeting of olfactory system during embryonic development however these genes account only for 30% of KS cases emphasizing the need for further characterization and identification of other genes. While these proteins are involved in ontogenesis olfactory and GnRH system, genetic screening of molecules in patients suffering from normosmic idiopathic HH lead to identification of genes encoding for Kisspeptin receptor-GPR54, TAC-TACR3, LEP-LEPR, PCSK-1, GnRH receptor-GnRHR and GnRH-1 itself that play a crucial role in occurrence of puberty or adult reproduction. Here, for my PhD thesis, we focused on studying the role of guidance molecule Semaphorin3A (Sema3A)-Neuropilin1 (Nrp1) interactions in ontogenesis of GnRH neurons during embryonic development while in adults we first addressed the question if hypothalamic Kisspeptin neurons interact with neurons containing neuronal nitric oxide synthase (nNOS), the mutation of which causes HH in mice, and physiological significance of this interactions in regulation of GnRH neurons and neuroendocrine control of female reproduction. Finally our results demonstrate that Sema3A-Nrp1 interactions are implicated in ontogenesis of olfactory and GnRH neurons during embryonic development and nNOS neurons are important mediators of peripheral estrogens-kisspeptin signaling onto GnRH neurons and adult reproduction and propose to further study the implication of nNOS neurons in reproductive pathologies.

The six possible combinations of two climate models and three methods for calculating the melting of snow and ice are used to estimate current values of accumulation and ablation on the Greenland and Antarctic ice sheets. This allows the contrasting of high vs. low resolution climate input and to assess the reliability of simple temperature based parameterizations of melting when compared to a physical model of the seasonal evolution of the snow cover. In contrast to past efforts at modelling the mass balance of Greenland and Antarctica, the latter model allows an explicit calculation of the formation of meltwater, of the fraction of meltwater which refreezes and of runoff in the ablation region, this is not the case for the other two melt models. While the higher resolution GCM (ECHAM 4) does bring the estimation of accumulation closer to observations, it fails to give accurate results in its predictions of runoff. The simpler climate model (MIT 2D LO) overestimates accumulation in Antarctica but produces satisfactory estimates of runoff from the Greenland ice sheet. Both models reproduce some of the characteristics of the extent of the wet snow zone observed with satellite remote sensing, but the MIT model is closer to observations in terms of areal extent and intensity of the melting. The temperature dependent melting parameterizations generally require an accuracy in the climatic input beyond what is currently achieved to produce reliable. Because it is based on physical principles and relies on the surface energy balance as input, the snow cover model is believed to have the capability to respond adequately to the current climatic forcing as well as to future changes in climate. / Includes bibliographical references (p. 31-34). / Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/) / Supported by the Alliance for Global Sustainability, the MIT Joint Program on the Science and Policy of Global Change and NASA as part of the NASA GISS Interdisciplinary EOS Investigation NAG5-7204

En la presente Tesis Doctoral se ha ampliado el estudio de la aplicación de complejos quirales de rodio derivados de ligandos P-OP altamente modulares en hidrogenación asimétrica. Se observaron resultados sobresalientes en la hidrogenación asimétrica de un amplio rango de alquenos funcionalizados, así como en alquenos estratégicamente diseñados, conducentes a intermedios avanzados en la síntesis de principios activos farmacéuticos. Se evaluó la coordinación de los ligandos P-OPcon precursores de iridio y se estudió su aplicación en la hidrogenación enantioselectiva de compuestos C=N. Se desarrollaron estrategias de activación de los sustratos, mediante el uso de ácidos de Brønsted como aditivos. Experimentos de marcaje isotópico permitieron profundizar en el mecanismo de la hidrogenación asimétrica de quinoleínas sustituidas mediada por dichoscomplejos de iridio / In the present PhD Thesis, we havebroadened the application of chiral rhodium complexes derived from our highly modular POP ligands in asymmetric hydrogenation. Outstanding results were observed in the enantioselective hydrogenation of a wide array of substrates, as well as in the hydrogenation of strategically devised prochiral alkenes leading to advanced intermediates of active pharmaceutical ingredients. We also evaluated the coordination of POP ligands to iridium precursors and studied their application to the hydrogenation of C=N-containing compounds. We developed activation strategies for substrate activation, which involved using Brønsted acids as additives. Isotopic labeling experiments allowed us to gain a deep understanding of the mechanism of the asymmetric hydrogenation of substituted quinolines mediated by our iridium catalysts.

To extend the knowledge of complex distillation arrangements for the separation of ternary mixtures and make them closer to implementation in industry is the motivation of this thesis work. Some design, operation, and control aspects are analysed, having the conventional distillation arrangements as comparison basis. The DWC is a complex distillation arrangement very attractive in terms of energy and cost savings. However, the DWC require large columns in order to be economically advantageous. Therefore, this arrangement is more attractive when the energy cost is high compared to the trays cost. From rigorous simulations of different separation examples, some synthesis rules have been obtained.Designs that minimise the distillation cost have been given special importance. DWC design procedures reported in the literature were based on only two decision variables. A new procedure that uses three decision variables for design optimisation has been proposed. It has been seen that the use of three decision variables is important to avoid excluding possible optimum designs.The control of the DWC is more complex than the control of the other distillation arrangements because the DWC has more operation degrees of freedom. The approach in this work has been to solve the DWC control by levels: stabilisation, composition control, and optimising control. When the manipulated variables for DWC stabilisation control are the distillate and the bottoms flowrate, which is the most common stabilisation control structure in the literature, the DWC presents high directionality and interaction. Besides, this stabilisation control structure is not appropriate to the DWC because the DWC has typically high reflux ratios. When the manipulated variables for stabilisation control are the reflux flowrate and the boilup, the DWC has better controllability and larger stability margins. Linear analysis tools are useful to select the set of manipulated variables for the DWC composition control. The preferred set of manipulated variables and the controllability of the corresponding control structure depend on the nominal operation. The DWC has two extra operation degrees of freedom that permit an operation optimisation. This optimisation is used to minimise the boilup. At a non-optimal operation, the controllability is improved. Therefore, a trade-off appears between operation optimisation and controllability. Changes in the design of the DWC can be used to improve its controllability. High directionality is a problem associated to DWC that may be improved using a large number of trays. On the other hand, DWC optimal designs have an equilibrated distribution of distillation effort between sections which, if broken, may also present improve the controllability. As found for operation, also for design, leaving optimal conditions permits to improve the controllability. Alternatively, for the composition control of the DWC, Dynamic Matrix Control is analysed. It is found that DMC performs worse than the diagonal feedback control strategy. The DWC extra operation degrees of freedom can be used dynamically for optimising control. Due to a marked directionality found in the response surface, DWC operation may be kept close to optimal operation using only one of the operation degrees of freedom. Optimising control of the DWC through the feedback control of a variable that characterises the optimal operation is possible. Some measurable variables are able to maintain optimal conditions with certain accuracy.The controllability of the DWC is compared to the controllability of other distillation arrangements. In general, the complexity of a distillation arrangement makes its energy efficiency better and its controllability worse. However, important exceptions have been found: - The DWC may give important energy savings as well as the best controllability if it is operated at non-optimal conditions. - When the manipulated variables for stabilisation are internal flows (reflux rates and boilups), the controllability of the DWC is better than the controllability of the other distillation arrangements. The DWC controllability is found to be more interesting for long columns. Therefore, the DWC needs long columns to be really attractive in terms of energy as well as in terms of controllability. In the literature, DWC controllability was misevaluate. In this thesis work, it is seen that, thanks to the arrangement complexity, the DWC may give at the same time energy savings and a good controllability, what makes it very attractive. To know the influence of the non-modelled detail and to obtain experimental results for the DWC is the most important step in the way to DWC implementation in industry.

Urban wastewater treatment plants produce a variety of residuals during their operation, the typology of which are in function of the design of the treatment process. The problem aborded in the present thesis refers to the sludge produced as a result of the treatment. After the banning of disposal to continental and/or marine waters, established at the EU through Directive 91/271 CEE and then in Spain trough Royal Decree [RD 11/95] those sludges should be object, essentially after treatment, of controlled using or disposition. Previously to the using or disposition a previous treatment can be required, that could be organic (essentially composting with other amendments), drying or other physic-chemical treatment, between those last alkaline stabilization. Alkaline stabilization can accomplish on a single step reduction or elimination of pathogen vectors, smell elimination and a reduction in the putrefaction potential. Its base is the alteration of the physic-chemical characteristics of the environment of the sludge by addition of alkaline material. One of the processes of inertization, object of the analysis proposed in the present thesis, is the treatment realized trough addition of calcium oxide. Essentially it is a physic-chemical treatment trough which it is possible to obtain a dry product with the addition of calcium oxide (quicklime) to the urban wastewater sludge. The result of the chemical reactions and water evaporation is oriented to obtain a dry product (10% humidity) as powder and with a reduction of mass in relation to the original wastewater sludge of about 40%. The realized work have been developed over the basis of the analysis of the technical, economical and environmental feasibility of the proposed alternative, using though normalized methodology on each of the different concrete aspects that are developed. A very important part of the experimental work which validates the technology under study has been developed at pilot plant level. Additionally, the proposed management alternative of the sludge includes using the inertized sludge as a secondary raw material in Portland cement clínker production, having been developed a industrial pilot test to validate the theoretical hypothesis been established. The thesis has been developed in the core of task 6b of Project Sostaqua in program CENIT, promoted by the Centro para el Desarrollo Tecnológico e Industrial (CDTI). This had as an objective the creation of new knowledge to contribute to the development of a sustainable water life cycle. Being the sludge part of that cycle, task 6b has intended demonstrate the feasibility of the treatment with addition of alkaline agents, in this case with addition of calcium oxide. Over the basis of the obtained results it has been considered that the proposed process constitutes a feasible alternative to the management of the urban wastewater sludge. Considering that this management it is a difficult task to abroad, due to the technical difficulties implied, it should be convenient to diversify the alternatives in order to have backup treatment capacity in order to avoid the final disposition to landfill.

En la tesis se ha desarrollado el trabajo: La difusión de la Química en España durante la primera mitad del siglo XIX, a través de las revistas científicas.El estudio de las revistas científicas, el vaciado sistemático y el análisis de los artículos que versaban sobre la Química, teórica y técnica, desarrollada y tratada como ente y ciencia autónoma, durante este periodo, han constituido nuestro objetivo. Las fuentes principales para el desarrollo de este trabajo provienen de los repertorios de revistas y publicaciones contenidas en los catálogos de LÓPEZ PIÑERO, J.M.; TERRADA, M.L. (1990) y TEN, A.E.; CELI, M (1996). Además de otras publicaciones científicas localizadas en fondos de diversas Hemerotecas y Bibliotecas de Universidades, de Ateneos, de Academias del País y de Ayuntamientos de diferentes lugares de España.La investigación se ha organizado en torno a unos puntos básicos. Estudiamos primero el entorno científico e histórico, atendiendo a la difusión de los conocimientos científicos para llegar después a abordar las publicaciones científicas y el contenido de sus artículos relacionados con el mundo de la química y de su técnica. Hemos estructurado así la memoria en diez capítulos:1. Introducción, materiales y método.2. Difusión de los conocimientos científicos durante la primera mitad del siglo XIX.3. Entorno histórico-científico. papel desempeñado por la química durante la revolución industrial.4. La química en la prensa escrita durante la primera mitad del siglo XIX.5. Análisis bibliométrico de las publicaciones clasificadas.6. Vaciado de las publicaciones en el volumen anexo.7. Análisis de los artículos de las publicaciones.8. Estudio y análisis pormenorizado de los artículos atendiendo a cada uno de los campos de los registros.9. Conclusiones.10. Bibliografía. Con el fin de vertebrar toda la información recogida, creamos una metodología de vaciado, agrupando los campos estudiados en tres Registros Generales: Datos bibliográficos Descripción de contenidos Análisis de contenidosEl vaciado concreto de los artículos de las revistas nos proporcionó los datos de apoyo que permitieron avanzar hacia las conclusiones de nuestro trabajo:La prensa científica relativa a la Química durante esta primera mitad del XIX, fue escasa, su evolución coherente con las transformaciones sociales, y paralela a los momentos álgidos de la economía. También su asentamiento coincide con la autonomía de esta ciencia en una sociedad que consolida las fórmulas del liberalismo propios de muchos países del occidente europeo.Por otra parte, la carencia de un entramado industrial no permitió una retroalimentación entre las publicaciones periódicas y el progreso industrial. No encontramos una comunidad significativa de profesionales químicos, aunque se percibe ya claramente la existencia de una protocomunidad de estos profesionales. No hubo un desarrollo industrial en esta primera mitad del siglo, tan sólo podemos hablar de una incipiente transformación manufacturera en Cataluña.En cuanto a, la asunción por parte de las revistas, de los saberes químicos como punto de apoyo de procedimientos y procesos industriales de algunos sectores, podemos decir que nos reflejan la existencia de un cambio en el tipo de literatura científica en el que el libro pierde protagonismo en este ámbito.A través de los artículos de las publicaciones hemos conocido el alcance de esta actividad científica. La Química comenzaba a influir paulatinamente en la vida cotidiana, iniciaba su participación en los procesos manufactureros. Dejaba entrever ya, esta ciencia, el importante papel catalizador que asumiría en posteriores desarrollos industriales. La misteriosa belleza de la Química comenzaba su camino en nuestro país. / The study of scientific journals, systematic compilation and analysis of articles which deal with theoretical and technical chemistry developed and treated as autonomous being and science during this period, constitute its target. The main sources for its development come from the repertories of journals contained in catalogs of LÓPEZ PIÑERO, JM; TERRADAS, ML (1990) and TEN, AE, CELI, M (1996), also scientific publications located in paper and regular libraries of: Universities, associations, academies and Town Councils in different places of Spain. To structure the collected information, a methodology is established for the compilation (bibliographic data, description and content analysis), which follows towards the conclusions of the work: · Scientific press concerning chemistry during these years was scarce; its evolution consistent with the social transformation and parallel to the periods of economic growth. Its settlement is in line with the autonomy of this science in a society that reinforces ways of liberalism typical in many western European countries. · The lack of an industrial framework did not allow a feedback between these publications and the industrial progress. A significant community of chemists is not present in this period, although the existence of early groups of these professionals is perceived. There was no industrial development in this period, with the only exception of an emerging manufacturing transformation in Catalonia. · It can be said that the assumption by the journals of chemical knowledge as a lever of industrial processes and procedures in certain sectors do reflect the existence of a change in the type of scientific literature in which the book loses prominence. · Through the articles the extent of this scientific activity has been acknowledged. Chemistry gradually began to influence daily life and began its involvement in manufacturing processes, hinting the important catalytic role it would assume in later industrial developments. The mysterious beauty of chemistry began his journey in our country.

Wave storms and river inputs have been found to be the dominant forcing mechanism of sediment transport in continental shelves dominated by medium to large rivers around the world (e.g. Drake and Cacchione, 1985; Sherwood et al., 1994; Ogston and Stemberg, 1999; Traykovski et al., 2000; Wadman and McNinch, 2008) and in the northwestern Mediterranean Sea (Jiménez et al., 1999; Puig et al., 2001; Guillén et al., 2002, 2006; Palanques et al., 2002, 2011; Ferré et al., 2005; Roussiez et al., 2005; Ulses et al., 2008). However, the contribution of “small” Mediterranean river systems in fine-grained sediment dynamics is not well known. Flood and storm events redistribute not only sediment but also all the associated matter as well, such a heavy metals, which are indicators of the impact of industrial and urban activities. For these reasons, the present thesis project involves studying the dynamics of sediments and associated heavy metals across the inner continental shelf off the Besòs River (Barcelona), and in particular determining the effect of floods and storms in a littoral system affected by industrial and urban activities. To this end, several oceanographic surveys were carried out between 20 and 40 m water depths in the Barcelona continental shelf to obtain a variety of data: to register vertical hydrographical profiles (temperature, salinity and turbidity); to record time series of physical parameters (currents, salinity, temperature, turbidity and seabed variation) by deploying oceanographic equipment; and to take sediment samples (short cores and Van Veen grabs) and suspended and downward particulate matter from water samples and sediment traps for further sedimentological and geochemical analysis. The time period of the present study comprised three seasons, from autumn 2007 to spring 2008, which showed distinct features between them. The purpose of section 3 was to describe the main hydrographic and hydrodynamic conditions during the study period to support the interpretation of sediment transport processes. Three different periods in terms of storm and river activity matched the natural seasons of the year: The period comprised between end of September 2007 and December 2007 (autumn) was characterized by an intense frequency of northeastern-eastern storms mostly coupled with high but short river discharges and a convergence of the across-shelf current between 20 m and 30 m water depths; between January and early March 2008 (winter), the wave and river activity and frequency were reduced significantly with offshore currents dominating the across component; and finally, from March to mid June 2008 (spring), specially between May and June 2008, river discharges lasted more than one month and occurred under low wave energy conditions or in conjunction with S-SE and SW wave storms. The sediment response to the forcing conditions observed during the study period was analyzed in section 4. The grain size and porosity measurements taken in all the sediment samples collected during the experiment (sediment cores, sediment grabs and sediment traps) showed a high spatial and temporal variability of the bottom sediment properties, downward sediment fluxes and near-bottom sediment concentrations across the inner-shelf. Those changes were associated to periods of high wave shear stress, river and current energy and therefore, were more intense in autumn 2007 and spring 2008. However, an across shelf spatial variability was observed during this period which was associated to the sediment availability (i.e. critical shear stress gradients). As a result, the same storm produced larger nearbottom sediment concentration in deeper waters due to the limitation on the availability of resuspendable sediment in the near-shore. The resultant sediment dynamics across the inner shelf and results in sediment transport modeling during a resuspension event were then addressed in section 5. In the inner shelf off Barcelona, the general circulation of sediment transport was mainly directed towards the southwest (along-shelf) during the study period, however, the seaward component was considerably relevant and favored the segregation of coarse and fine sediment from the nearshore towards deeper areas. Nonetheless, noticeable differences in sediment transport patterns were observed across the inner shelf. Nearbottom sediment transport at 20 m water depth was mainly offshore, while in deeper parts of the inner shelf the along-shelf component dominated the sediment transport. The resulting sediment transport and its variability across the shelf, deposited riverine and storm-derived fine sediment in an along-shelf path towards the southwest between 20 m and 30 m water depth and only under the strong storms were transferred seaward toward the 40 m water depth site and to deeper areas. These differences had in turn a strong seasonal component related to the availability of fine sediments from river inputs and the energy of waves and currents. In this sense, autumn and spring registered events affected mostly at 20 m water depth and autumn and early winter months were more energetic at deeper waters reversing the sing of sediment transport gradients across the shelf. During this event, the sediment transport model captured adequately the transport rates across the inner shelf and allowed the estimation of the integrated vertical sediment flux in 10 meters of the water column above the seabed. Consequently with the observed and modelled pattern of sediment transport, the seabed variation was higher at 30 m than at 20 m water depth, with a total seabed erosion of about 10 cm and 4 cm, respectively. The implications of the sediment dynamics during the study period in the transference of heavy metals from the Besòs River across the shelf was analyzed in section 6. The Besòs River introduced heavy metal pollutants into the nearshore continuously associated with the regular regime and sporadically during increments in river discharge. Only during high wave and current energy the anthropogenic contamination, previously deposited in the shallow inner-shelf, reached deeper areas. As a result, the most contaminated sediment accumulated southwestward from the river and sewer mouths along the inner shelf decreasing offshore. The most affected area associated to the Besòs river influence was located around the tripod sites, especially between 20 m and 30 m water depths decreasing offshore.Finally, the main conclusions and proposals for future research of this thesis are discussed in section 7. In it, the importance of "small" Mediterranean river systems in the transfer of sediment across the continental shelf is highlighted from the sediment transport events observed during the study period. / El oleaje durante temporales y los aportes fluviales han sido considerados como los mecanismos de forzamiento dominantes del transporte de sedimento en las plataformas continentales afectadas por ríos medianos y grandes en todo el mundo (por ejemplo, Drake y Cacchione, 1985; Sherwood et al., 1994; Ogston y Stemberg, 1999; Traykovski et al., 2000; Wadman y McNinch, 2008) y en el Mediterráneo noroccidental (Jiménez et al., 1999; Puig et al., 2001; Guillén et al., 2002, 2006; Palanques et al., 2002, 2011; Ferré et al., 2005; Roussiez et al., 2005; Ulses et al., 2008). Sin embargo, la contribución de "pequeños" sistemas fluviales mediterráneos en la dinámica de sedimento está poco estudiada. El oleaje y las tormentas no solo redistribuyen sedimentos si no también toda la materia asociada, así como, metales pesados, que son indicadores del impacto de las actividades industriales y urbanas. Por estas razones, el presente proyecto de tesis implica el estudio de la dinámica de sedimento y metales pesados asociados a través de la plataforma continental del río Besòs (Barcelona), y en particular, determinar el efecto de los temporales y tormentas en un sistema litoral afectado por actividades industriales y urbanas. Para este fin, varias campañas oceanográficas se llevaron a cabo entre 20 y 40 m de profundidad en la plataforma continental de Barcelona donde se tomaron gran variedad de datos y muestras: perfiles verticales hidrográficos (temperatura, salinidad y turbidez); series temporales de parámetros físicos (corrientes, salinidad, temperatura, turbidez y la variación del fondo) mediante el anclaje de equipos oceanográficos, y muestras de sedimento (testigos cortos de sedimento y dragas Van Veen) y de partículas en suspensión (a partir de muestras de agua y trampas de sedimentos) para análisis sedimentológicos y geoquímicos. El período de estudio comprendió tres estaciones, desde otoño de 2007 a primavera de 2008, que mostraron características distintas entre ellas. En la sección 3 se describen las principales condiciones hidrográficas y la hidrodinámica durante el período de estudio para apoyar la interpretación de los procesos de transporte sedimentario. Se identificaron tres periodos diferentes en función de la actividad fluvial y la del oleaje que coincidieron con las estaciones naturales del año: El período comprendido entre finales de septiembre de 2007 y diciembre de 2007 (otoño) se caracterizó por una intensa frecuencia de temporales del noreste-este junto con incrementos en la descarga del río y una convergencia de la componente across-shelf de la corriente entre 20 m y 30 m de profundidad; entre enero y principios de marzo de 2008 (invierno), la actividad y la frecuencia del oleaje y del río se redujeron significativamente con predominio de la componente offshore de la corriente; y, por último, de marzo a mediados de junio de 2008 (primavera), especialmente entre mayo y junio de 2008, las descargas fluviales se intensificaron durante más de un mes produciéndose en condiciones de baja energía del oleaje o en combinación con temporales del S-SE o SW. La respuesta del sedimento del fondo a las condiciones de forzamiento observadas durante el período de estudio se analizó en la sección 4. El tamaño medio de grano y la porosidad de todas las muestras de sedimento recogidas durante el experimento (testigos, dragas y trampas) mostraron una alta variabilidad espacial y temporal. Los flujos verticales de sedimento y la concentración de sedimento en suspensión cerca del fondo también variaron a través de la plataforma interna durante el periodo de estudio. Estos cambios se asociaron a eventos de fuerte oleaje y corrientes y a descargas del río y, por tanto, fueron más intensas en otoño de 2007 y primavera de 2008. Sin embargo, se observó una variabilidad espacial a través de la plataforma interna durante estos eventos que se asoció a la disponibilidad de sedimento (es decir, a gradientes de “critical shear stress”). Como resultado, una misma tormenta produjo una concentración de sedimento cerca del fondo mayor en aguas más profundas debido a que la disponibilidad de sedimento fino era limitada en aguas someras. En la sección 5, se analiza la dinámica de sedimento resultante a través de la plataforma interna y los resultados obtenidos en el modelado del transporte de sedimento durante un evento de resuspensión. En la plataforma interna de Barcelona, la circulación general del transporte sedimentario se dirigió principalmente hacia el suroeste (along-shelf) durante el período de estudio, sin embargo, la componente onshore fue bastante relevante y favoreció la segregación de sedimento grueso y fino desde la costa hacia zonas más profundas. Sin embargo, se observaron diferencias notables en el transporte de sedimento a través de la plataforma interna. A 20 m de profundidad, el transporte de sedimento fue principalmente onshore, mientras que zonas más profundas de la plataforma interna la componente along-shelf dominó el transporte. Este patrón de transporte, depositó sedimentos del río y depositados previamente en una trayectoria along-shelf hacia el suroeste entre 20 m y 30 m de profundidad y sólo durante los temporales más fuertes fueron transportados hacia 40 m de profundidad y probablemente a zonas más profundas de la plataforma continental. Estas diferencias tuvieron a su vez una fuerte componente estacional relacionada con la disponibilidad de sedimentos fluviales finos y la energía del oleaje y las corrientes. En este sentido, en otoño y primavera los eventos registrados afectaron mayormente a 20 m de profundidad y a finales de otoño y comienzos del invierno fueron más activos en aguas profundas, cambiando el gradiente del transporte sedimentario a través de la plataforma. Durante este evento, el modelo de transporte sedimentario capturó adecuadamente las tasas de transporte a través de la plataforma y permitió estimar el flujo vertical integrado de sedimento en 10 metros de columna de agua sobre el fondo marino. En consecuencia con el patrón de transporte de sedimento observado y modelado, la variación del fondo marino fue superior a 30 m que a 20 m de profundidad, con una erosión de alrededor de 10 cm y 4 cm, respectivamente. Las implicaciones de la dinámica sedimentaria durante el período de estudio en la transferencia de metales pesados des del río Besòs a través de la plataforma se analizó en la sección 6. El río Besòs introdujo metales pesados cerca de la costa continuamente durante el régimen de descarga regular y esporádicamente en incrementos de caudal del río. Sólo durante las condiciones más altas de oleaje y corrientes la contaminación antropogénica, previamente depositada en la parte somera de la plataforma, alcanzó zonas más profundas. Como resultado, el sedimento más contaminado se acumuló hacia el suroeste del río y de las desembocaduras de los pluviales. La zona más afectada asociada a la influencia del río Besòs se localizó especialmente entre 20 m y 30 m de profundidad disminuyendo en profundidad. Por último, las principales conclusiones y propuestas de futura investigación de la presente tesis se abordan en la sección 7. En ella, se destaca la importancia de "pequeños" sistemas fluviales mediterráneos en la transferencia de sedimento a través de la plataforma continental que se manifiesta a partir de la secuencia de eventos de transporte sedimentario observada durante el periodo de estudio.

Els glicolípids i particularment els glicoesfingolípids són compostos d’interès perquè poden interaccionar amb biofactors tot inhibint o interferint en processos fisiològics de les cèl•lules. Per exemple, els glicoesfingolípids que recobreixen les membranes cel•lulars poden interaccionar en processos de reconeixement amb bactèries, virus i toxines com per exemple la toxina del Còlera la qual inicia el procés d’infecció pel reconeixement de glicolípids com el GM1. Tot i que l’ús d’antibiòtics és el tractament més emprat, la resistència als antibiòtics a zones endèmiques fa necessària la recerca en síntesi d’inhibidors basats en derivats de carbohidrats. Donat que la síntesi de compostos glicoconjugats que presenten multivalència ha resultat competitiva en la preparació d’inhibidors contra patògens en aquest treball s’ha estudiat la síntesi de nous mimètics basats en -galactosilceramides; l’acoblament Sukuki-Miyaura en 2-iodoglicals per obtenir nous precursors de carbohidrats i l’anclat de -galactosilceramides en suports com polímers hiperramificats per tal d’avaluar la seva inhibició front la toxina del Còlera. / Los glicolípidos y particularmente los glicoesfingolípidos son compuestos de interés porque pueden interaccionar con biofactores inhibiendo o interfiriendo en procesos fisiológicos de las células. Por ejemplo, los glicoesfingolípidos que recubren las membranas celulares pueden interaccionar en procesos de reconocimiento con bacterias, virus y toxinas como por ejemplo la toxina del Cólera la cual inicia el proceso de infección a través del reconocimiento de glicolípidos como el GM1. Aunque el uso de antibióticos es el tratamiento más empleado, la resistencia a los antibióticos en zonas endémicas hace necesaria la investigación en síntesis de inhibidores basados en derivados de carbohidratos. Dado que la síntesis de compuestos glicoconjugados que presentan multivalencia ha resultado competitiva en la preparación de inhibidores contra patógenos, en este trabajo se ha estudiado la síntesis de nuevos miméticos basados en -galactosilceramidas; el acoplamiento Sukuki-Miyaura en 2-yodoglicales para obtener nuevos precursores de carbohidratos y el anclado de -galactosilceramidas en suportes como polímeros hiperramificados con el fin de avaluar su inhibición frente la toxina del Cólera. / Glycolipids such as glycosphingolipids are interesting compounds because they can interact with biofactors by inhibiting or interfering in physiological processes on cells. For instance, the glycolipids which present on cellular membranes can interact with bacteria, virus and toxins. In deed, Cholera toxin starts its infective process once it has recognized glycolipids such as GM1. Although the use of antibiotics is the commonest treatment against this disease, the antibiotic resistance in endemic areas makes the investigation in the synthesis of inhibitors based on carbohydrate derivatives necessary. Due to the synthesis of multivalent glycoconjugated compounds have been competitive in order to prepare inhibitors against these pathogens, in the present work we have studied: the synthesis of new mimetics based on -galactosylceramides; the Suzuki-Miyaura cross coupling in 2-iodoglycals in order to obtain new carbohydrate precursors and the anchoring of -galactosylceramides in scaffolds such as hyperbranched polymers in order to evaluate their inhibition binding against to Cholera toxin