A preparação do EM Pd foi escolhida pelo fato de já terem sido estudados em nossos laboratórios os EM Ni e EM Pt. Estes três eletrodos modificados (EMs) foram utilizados nas hidrogenações eletrocatalíticas (HEC) de substratos orgânicos para comparação de suas reatividades. A preparação deste novo eletrodo modificado revestido pelo filme misto poli-[éter alílico do p-(2-etilamônio) benzeno] e co-monômero éter fenil e alílico no suporte de bastão de grafite contendo partículas de Pd foi iniciada com a síntese do éter alílico do p-(2-etilamônio) benzeno a partir da acetamida do p-(2-etilamônio). A utilização do co-monômero éter fenil e alílico na estrutura do filme polimérico se fez na tentativa de espaçar a malha polimérica para conseguir melhorar os resultados das HEC de substratos orgânicos, pois estes teriam maior facilidade de permear (difundir) pela malha e também proporcionar um aumento na quantidade de partículas de paládio incorporadas ao filme. Depois da preparação, utilização e comparação dos EMs Ni, Pd e Pt foram desenvolvidos novos EMs mistos visando aumentar a eficiência nas HEC dos substratos orgânicos. O EM misto Ni/Ni já havia sido preparado e estudado nas HEC mostrando uma eficiência moderada. Preparou-se então os EMs mistos Ni/Pd e Ni/Pt para compará-los com o EM Ni/Ni e com os EMs Ni, Pd e Pt para verificar se ocorreria um aumento na eficiência nas HEC. A preparação destes EMs mistos foi feita utilizando a técnica de electroless. A eficiência dos EMs foi verificada através da GH a partir de uma solução de ácido sulfúrico, do volume de hidrogênio gerado, medidas de potencial de circuito aberto e de reação de HEC de substratos orgânicos. A caracterização dos EMs foi feita pelo cálculo da massa de partículas incorporadas e análise de raios X e MEV-EDX. Os substratos orgânicos estudados nas HEC foram: benzaldeído, n-valeraldeído, isoforona, 2-cicloexen-1-ona, cicloexanona, acetofenona, benzofenona, eugenol, isoeugenol, fenilacetileno, 3-butin-1-ol, benzonitrila, fenilacetonitrila, malononitrila e valeronitrila. Comparando-se os EMs Ni, Pt, Pd, Ni/Ni, Ni/Pd e Ni/Pt, o que levou aos melhores rendimentos nas HEC foi o EM misto Ni/Pd. A HEC da acetofenona e benzofenona levou a resultados inéditos na literatura com a hidrogenação dos anéis aromáticos. / The modified electrode (ME) Pd was chosen because ME Ni and ME Pt had already been studied in our laboratory. These three different MEs were used in the electrocatalytic hydrogenation (ECH) of organic substrates so that their reactivity could be compared. The preparation of the new modified electrode ME Pd by using the mixed film poly-[ether allyl p-(2-ammoniumethyl) benzene] and the co-monomer allyl phenyl ether in carbon stick containing Pd particles. The preparation was initiated by synthesizing the allyl p-(2-ammoniumethyl) benzene ether through reaction with the acetamyde of the p-(2-ammoniumethyl) group. The co-monomer allyl phenyl ether in a polymeric film was used in an attempt to obtain more space between the polymeric film and to achieve better results in the ECH of organic substrates, since they could be introduced through the polymer and increase the quantity of Pd particles of incorporated in to the film. After the preparation of the MEs Ni, Pd and Pt and after they had been used and compared, new mixed MEs were developed in order to study their efficiency in the ECH of organic substrates. Mixed ME Ni/Ni had already been prepared and studied in our laboratory and it was shown to be moderately efficient for ECH. Mixed ME Ni/Pd and Ni/Pt were prepared so that they could be compared with mixed ME Ni/Ni, ME Ni, ME Pd and ME Pt. The preparation of these mixed MEs was carried out by electroless deposition. The efficiency of these MEs was verified by hydrogen generation from a mineral acid solution, hydrogen generation volume, potential of the open circuit and ECH of organic substrates. The characterization of the MEs was done by calculating the mass of incorporated particles and by SEM-EDX analyses. The organic substrates used for in ECH were benzaldehyde, n-valeraldehyde, isophorone, 2-cyclohexen-1-one, cyclohexanone, acetophenone, benzophenone, eugenol, isoeugenol, phenylacetylene, 3-butin-1-ol, benzonitrile, phenylacetonitrile, malononitrile and valeronitrile. A comparison of these MEs shows that the mixed ME Ni/Pd are the most efficient for ECH for all studied substrates. Acetophenone and benzophenone gave fully hydrogenated products; a fact that has not yet been published in the literature.

Les acides carboxyliques aliphatiques sont utilisés dans de nombreux secteurs industriels et leur importance économique augmente. Ils sont actuellement produits en grande quantité, grâce à des procédés utilisant le C0 qui est principalement non- renouvelable. L'anhydride carbonique est une molécule potentiellement écologique, renouvelable et abondante. Cette thèse décrit l'étude et l'optimisation d'un système catalytique homogène de Rh, utilisé pour produire des acides carboxyliques aliphatiques à partir de substrats oxygénés, C02 et H2. Le système consiste en un précurseur de Rh, un additif à base d'iodure et un ligand PPh3, fonctionnant dans un réacteur discontinu sous une pression de C02 et de H2. Les conditions de réaction ont été optimisées pour chaque classe de substrats étudiés: alcools primaires et secondaires, cétones, aldéhydes et époxydes. 30 molécules différentes ont été converties en acides carboxyliques, conduisant à des rendements jusqu'à 80%. En plus, le système a été étudié avec une approche de « Design of Experiment », ce qui a permis d'obtenir des informations supplémentaires concernant les paramètres étudiés. Le mécanisme de réaction et les espèces catalytiques actives ont été étudiés par différentes manipulations comme des réactions compétitives, des expériences de RMN et l'utilisation de molécules marquées. La réaction est composée de transformations non catalytiques et de deux étapes catalytiques. La réaction se déroule à travers une réaction de reverse Water Gas Shift (rWGSR) transformant le C02 et l'H2 en C0 et H20, qui sont consommés dans l'hydrocarboxylation suivante de l'alcène formé in situ pour livrer l'acide carboxylique. Le système catalytique est similaire aux catalyseurs traditionnels à base du Rh pour les réactions de carbonylation et de Water Gas Shift. Le PPh3 est nécessaire pour fournir des ligands supplémentaires, permettant au catalyseur de fonctionner avec une quantité minimale de ligand toxique de C0. En plus, un système catalytique hétérogène a été étudié pour la même réaction. « Single Atom Catalysts » (SACs) reçoit beaucoup plus d'attention que les solutions catalytiques, car il présente à la fois les avantages des catalyseurs homogènes (sélectivité, haute activité) et des catalyseurs hétérogènes (séparation et recyclage faciles). Des atomes de rhodium simples dispersés sur du graphène dopé avec l'N ont été synthétisés et caractérisés, obtenant des informations concernant la structure chimique et physique du matériau. Finalement, ils ont été testés ainsi que les catalyseurs pour l'activation du C02, la production d'acides carboxyliques, les réactions d'hydrogénation et d'hydrogénolyse / Aliphatic carboxylic acids are used in many industrial sectors and their importance from an economical point of view is increasing. They are currently produced in large quantities, through processes exploiting the mostly non-renewable C0 as C1 synthon. Carbon dioxide is a potential environmentally friendly, renewable and abundant C1 building block. The aim of this work is to provide a catalytic protocol converting C02, H2 and oxygenated substrates to obtain useful chemicals, like carboxylic acids.To this end a homogeneous catalytic Rh system, used to produce aliphatic carboxylic acids starting from oxygenated substrates, C02 and H2 was investigated and optimized. The system consists of a Rh precursor, iodide additive and PPh3 ligand working in a batch reactor under C02 and H2 pressure. The reaction conditions were optimized for each class of investigated substrates: primary alcohols, secondary alcohols, ketones, aldehydes and epoxides. The reaction scope was investigated and 30 different molecules were converted into carboxylic acids, leading to yields of up to 80%. ln addition, the system was studied using a Design of Experiment approach, obtaining additional information regarding the studied parameters.The reaction mechanism and the catalytically active species were studied, by different experiments like competitive reactions, NMR and labelling experiments. This investigation resulted in a deeper knowledge of the reaction pathway, composed of some non-catalytic transformations and two catalytic steps. The reaction proceeds through a reverse Water Gas Shift Reaction (rWGSR) transforming C02 and H2 into C0 and H20, which are consumed in the following hydrocarboxylation of the in-situ formed alkene to give the final carboxylic acid product. The catalytic system is similar to traditional Rh carbonylation and Water Gas Shift catalysts. The PPh3 is needed to supply additional ligands allowing the catalyst to work in reaction conditions with a minimal amount of toxic C0 ligand. ln addition, a heterogeneous catalytic system was investigated for the same reaction. Single atom catalysts (SACs) are receiving much attention as catalytic solution, since they have both the advantages of homogeneous (selectivity, high activity) and heterogeneous (easy separation and recycling) catalysts. Single Rh atoms dispersed on N-doped graphene were synthesized and characterized, obtaining information regarding the chemical and physical structure of the material. Eventually, they were tested as catalysts for C02 activation, carboxylic acid production, hydrogenation and hydrogenolysis reactions / Aliphatische Carbonsauren werden in vielen industriellen Bereichen verwendet und ihre wirtschaftliche Bedeutung nimmt zu. Sie werden derzeit in gror.en Mengen hergestellt, indem das meistens nicht erneuerbare Kohlenmonoxid als C1-Synthon genutzt wird. Kohlendioxid ist ein potenziell umweltfreundlicher, erneuerbarer und abundanter C1-Baustein. Das Ziel dieser Arbeit ist die Entwicklung eines Protokolls zur katalytischen Umwandlung von C02, H2 und sauerstoffhaltigen Substraten, um nützliche Chemikalien, wie Carbonsauren zu erhalten. Zu diesem Zweck wird ein homogenes Rh-Katalysatorsystems zur Herstellung aliphatischer Carbonsauren aus sauerstoffhaltigen Substraten, C02 und H2 untersucht und optimiert. Das System besteht aus Rh-Prakursor, lodid-Additiv und PPh3 als Ligand, die in einem Batchreaktor unter C02 und H2 eingesetzt werden. Die Reaktionsbedingungen wurden für folgende Substratklassen optimiert: primare Alkohole, sekundare Alkohole, Ketone, Aldehyde und Epoxide. Es wurden insgesamt 30 verschiedene Substrate mit Ausbeuten bis zu 80% zu Carbonsauren umgesetzt. Darüber hinaus wurde das System mit einem ,,Statistische Versuchsplanung"-Ansatz untersucht, um zusatzliche lnformationen zu den untersuchten Parametern zu erhalten. Mechanismus und katalytisch aktive Spezies wurden durch verschiedene Experimente wie Konkurrenzreaktionen, NMR- und Markierungsexperimenten untersucht. Dies erschloss den Reaktionsweg, der aus mehreren nicht-katalytischen Transformationen und zwei katalytischen Schritten besteht. Die Reaktion verlauft durch eine ,,reverse Wassergas-Shift-Reaktion" (rWGSR), die C02 und H2 in C0 und H20 umwandelt. Diese werden wiederum bei der nachfolgenden Hydrocarboxylierung des in-situ gebildeten Alkens unter Bildung der Carbonsaure verbraucht. Das katalytische System ahnelt herkômmlichen Rh-Carbonylierungs- und WGSR-Katalysatoren. PPh3 fungiert als zusatzlicher Ligand, der es dem Katalysator ermôglicht unter den gleichen Reaktionsbedingungen mit minimaler Menge toxischen C0 als Liganden zu arbeiten. Zusatzlich wurde ein heterogenes katalytisches System für die gleiche Reaktion untersucht. ,,Single atom catalysts" (SACs) erhalten gror.e Aufmerksamkeit als neue Katalysatorklasse. Sie kombinieren die Selektivitat und hohe Aktivitat homogener und die einfache Abtrennung und Recycling heterogener Katalysatoren Verschiedene Katalysatoren aus auf N-dotiertem Graphen dispergierten Rh-Atomen, wurden synthetisiert und charakterisiert. Dadurch wurden lnformationen über die chemische und physikalische Struktur des Materials gewonnen und als Katalysatoren für C02-Aktivierung, Carbonsauresythese, Hydrierung und Hydrogenolyse getestet

De uma forma geral, animais ovíparos suprem sua prole somente com vitelo, composto principalmente por lipídios e proteínas. Em espécies de cecílias ovíparas e dermatófagas, as fêmeas mobilizam esses substratos energéticos para os ovários durante a vitelogênese e também utilizam esses mesmos compostos para a produção de uma pele mais espessa e nutritiva que servirá de alimento aos filhotes durante o cuidado parental. Em detrimento da grande importância do vitelo para o desenvolvimento de embriões e larvas, como apresentado, é curioso compreender como espécies ovíparas alocam parte da sua energia na produção de uma pele mais espessa, além de investirem na produção do vitelo. Desta forma, sendo as cecílias pouco conhecidas, é de grande importância entender os processos metabólicos e endócrinos envolvidos no armazenamento e na mobilização dos substratos energéticos ao longo do processo reprodutivo de machos e fêmeas, a fim de entender como ocorre o preparo das gônadas e da pele para a reprodução. Análises histológicas dos ovários e testículos foram realizadas, assim como a determinação de lipídios (e ácidos graxos dos fosfolipídios) e proteínas totais no fígado, músculo, gônadas, pele e plasma de machos e fêmeas de S. annulatus ao longo do ciclo anual. Além disso, a concentração plasmática dos esteróides gonadais (estradiol, testosterona e progesterona) foi também quantificada em ambos os sexos. De forma geral, oócitos em diferentes estágios de desenvolvimento foram encontrados nos ovários. A espermatogênese de Siphonops annulatus apresentou um padrão cístico como visto para os outros anamniotas, sendo o testículo formado por lobos que variam em número e tamanho. Com relação aos substratos energéticos, observamos que existe uma clara tendência em maior acúmulo de lipídios e proteínas nas gônadas das fêmeas que foram coletadas durante o inverno, caracterizadas por um desenvolvimento oocitário mais avançado, com a presença de oócitos vitelogênicos, sendo o mesmo observado para os machos. Em relação aos ácidos graxos, foi encontrado um padrão normalmente observado para os demais vertebrados, com a fração polar dos tecidos composta principalmente por ácidos graxos polinsaturados n6 em ambos os sexos. Destaca-se nas fêmeas uma grande mobilização de ácidos graxos dos tecidos de reserva para os ovários, principalmente os ácidos graxos polinsaturados, que são de grande importância para a vitelogênese e embriogênese. Alterações dos substratos no tecido dérmico da fêmea também foram observadas na primavera e no verão, sugerindo a importância deste tecido na dermatofagia. As análises hormonais demonstraram poucas variações ao longo do ano para ambos os sexos, devido à grande variação individual. Contudo, os valores de estradiol, testosterona e progesterona tendem a ser maiores para as fêmeas no inverno e para os machos durante a primavera. Os dados sugerem que o processo reprodutivo em S. annulatus mantida em cativeiro envolveu um processo de reostase programada, pois mesmo não havendo condições ambientais ideais, as fêmeas e os machos apresentam uma memória metabólica capaz de prepará-los para a reprodução. No entanto, o ambiente proporcionado pelo cativeiro suprimiu a ocorrência das fases finais do ciclo reprodutivo, como ovulação e cópula, resgatando o clássico conceito de reostase reativa. / Usually, oviparous animals keep their offspring only with yolk that is composed mostly of lipids and proteins. In oviparous and dermatophagic caecilians species, the females mobilize these energetic substrates to the ovaries during the vitellogenesis and also use these compounds to produce a ticker and nutritive skin that will be used as food for the offspring during parental care. In detriment of the great importance of the yolk to development of the embryos and larvae, as presented, it is curious to figure out how oviparous species allocate part of its energy to produce a thicker skin, beyond from investing in the production of yolk. Considering that caecilians are poorly known, it is important to understand the endocrine and metabolic processes involved in the storage and mobilization of energetic substrates during the reproductive process of males and females, in order to comprehend how the gonads and skin become ready for reproduction. Histological analysis of ovaries and testes were performed, as well as, total lipids (and fatty acids from phospholipids) and protein in liver, muscle, gonads, skin and plasma of males and females of S. annulatus during the annual cycle. Additionally, the plasma concentrations of gonadal steroids (estradiol, testosterone and progesterone) were quantified in both sexes. In general, oocytes at different stages of development were found in the ovaries. The spermatogenesis of Siphonops annulatus presented a cystic pattern as seen for other anamniotas, and the testes were formed by lobes which vary in number and size. Considering the energetic substrates, there is a clear tendency to a greater accumulation of lipids and protein in the ovaries in females collected in the winter, that were characterized by a more advanced stage of oocyte development, with the presence of vitellogenic oocytes. The same was observed for the males. Regarding to fatty acids, it was found a pattern commonly observed for others vertebrates, with the polar fraction of the tissues composed mainly by n6 polyunsaturated fatty acids in both sexes. It is important to highlight in females a great mobilization of fatty acids from the storages tissues to the ovaries, mainly the polyunsaturated fatty acids, which are of great importance for vitellogenesis and embryogenesis. Alterations in the energetic substrates of the dermal tissue of the female were also observed in spring and summer, suggesting the importance of this tissue in dermatophagy. The hormonal assays showed little variation throughout the year for both sexes, due to the large individual variation. However, the concentrations of estradiol, testosterone and progesterone have a clear tendency of being higher for females in the winter, and for males during the spring. The data suggests that the reproduction in S. annulatus maintained in captivity involved a programmed rheostasis process, because, even without the ideal environmental conditions, males and females presented a metabolic memory, that was enough to prepare the animals for reproduction. However, the environment provided by the captivity suppressed the occurrence of the final phases of the reproductive cycle, as ovulation and copulation, rescuing the classical concept of reactive rheostasis.

Climatério é a fase da vida da mulher em que ocorrem alterações hormonais que culminam em alterações metabólicas peculiares desse período, como por exemplo, diminuição do gasto energético e ganho ponderal. Com isso, os objetivos do presente trabalho foram mensurar o gasto energético e calcular a oxidação de carboidratos e lipídios, nos momentos basal e após uma sobrecarga lipídica, de mulheres pós-menopausadas com excesso de peso, estratificadas de acordo com o nível do estradiol plasmático (E2), bem como analisar peptídeos reguladores da fome e da saciedade nos mesmos momentos. Os grupos de mulheres foram: grupo 1- E2 39 pg/mL, 2- 40 E2 59 pg/mL, e 3- E2 60 pg/mL. As voluntárias receberam uma única refeição de 1100 kcal e 72% de lipídios, a qual caracterizou a sobrecarga lipídica. O gasto energético foi medido por calorimetria indireta por um período de cinco horas, sendo que as mensurações foram realizadas nos momentos 30, 60, 90, 150, 210 e 270 minutos. Os peptídeos reguladores da fome e da saciedade foram analisados no momento basal, após 30 e 270 minutos da sobrecarga lipídica. Os grupos foram comparados pelo teste não paramétrico Kruskal-Wallis, e para a comparação entre os momentos no mesmo grupo, foi utilizado o modelo de regressão linear com efeitos mistos, considerando p<0,05(*). Quarenta e quatro mulheres pós-menopausadas foram estudadas, com idade de 55±5 anos (média±desvio padrão), índice de massa corporal de 31±4 kg/m² e tempo de pós-menopausa de 8±7 anos. De uma forma geral, o gasto energético de repouso foi de 1337±194* kcal/dia, aumentando para 1476±295* kcal/dia nos primeiros 30´ pós-prandiais, e para 1513±318* kcal/dia ao final. Entre os grupos, não houve diferença estatística significativa. Em relação à oxidação de carboidratos, o valor basal foi de 151±95 mg/min, diminuindo para 146±95 mg/min nos primeiros 30´, e para 122±44 mg/min ao final (valores convertidos para mg/min para facilitar a leitura). O valor basal da oxidação lipídica foi de 37±30* mg/min, aumentando para 52±24* mg/min nos primeiros 30´ pós-prandiais, e para 63±21* mg/min ao final. Entre os grupos, não houve diferença estatística significativa quanto à oxidação de carboidratos, e quanto aos lipídios, houve diferença apenas entre os grupos 1 (maiores valores, p=0,03) e 2 ao final do experimento , e entre os grupos 1 e 3 (maiores valores, p=0,04) no momento 150´. Quanto aos peptídeos, o valor basal da leptina foi de 47±29 ng/mL, diminuindo para 44±27 ng/mL nos primeiros 30´ pós-prandiais, e para 43±26 ng/mL ao final. O valor basal da grelina foi de 753±522 pg/mL, diminuindo para 705±420 pg/mL nos primeiros 30´, e para 561±343 pg/mL ao final. O valor basal do peptídeo YY foi de 92±40* pg/mL, aumentando para 153±63* pg/mL nos primeiros 30´, e para 214±66* pg/mL ao final. Quanto à colecistocinina, o valor aos 30´ foi de 1,8±2,3 pg/mL, aumentando para 2,2±1,7 pg/mL ao final. Entre os grupos, houve diferença estatística significativa apenas da colecistocinina entre os grupos 2 e 3 (maiores valores, p=0,04) ao final. Sendo assim, houve um aumento significativo e gradual do gasto energético após a sobrecarga lipídica; predomínio da oxidação de carboidratos em relação à de lipídios, havendo uma diminuição em sua oxidação e um aumento da oxidação lipídica após a sobrecarga. Quanto aos grupos, não houve diferença estatística significativa em relação ao gasto energético, bem como à oxidação de carboidratos e lipídios na maior parte do tempo. Os peptídeos leptina e grelina diminuíram após a sobrecarga lipídica, enquanto que o peptídeo YY e a colecistocinina aumentaram, não havendo diferença estatística significativa entre os grupos na maior parte do tempo. Dessa forma, as variáveis estudadas se mostraram independentes do nível de estradiol plasmático. / Climaterium is the phase of women´s life when hormonal alterations occur and lead to peculiar metabolic responses such as a decrease in energy expenditure and weight gain. Thus, the aims of this study were to measure the energy expenditure, calculate carbohydrate and lipid oxidation, at resting and after a lipid overload, of postmenopausal women stratified according to their plasma estradiol value (E2) and evaluate hunger and satiety regulatory peptides in the same moment. Women´s groups were: group 1- E2 39 pg/mL, 2- 40 E2 59 pg/mL, and 3- E2 60 pg/mL. The volunteers received a 1100 kcal and 72% fat meal, which characterized the lipid overload. Energy expenditure was measured by indirect calorimetry for a period of five hours, and measurements were performed at 30, 60, 90, 150, 210 and 270 minutes. The hunger and satiety regulatory peptides were analyzed in the resting, 30 and 270 minutes after the lipid overload. The groups were compared using the nonparametric Kruskal-Wallis test. Linear regression model with mixed effects was used to compare the moments of the same group, considering p<0.05(*). Forty-four postmenopausal women were studied. Their age was 55±5 years (mean±standard deviation), body mass index was 31±4 kg/m² and they were in menopause for 8±7 years. In general, the resting energy expenditure was 1337±194* kcal/day, increasing to 1476±295* kcal/d in the first postprandial 30´, and to 1513±318* kcal/d in the end. There was no statistically significant difference between groups. Regarding carbohydrate oxidation, the baseline value was 151±95 mg/min, decreasing to 146±95 mg/min in the first 30´ and to 122±44 mg/min in the end (values were converted to mg/min for readability). The baseline value of lipid oxidation was 37±30* mg/min, increasing to 52±24* mg/min in the first 30´ and to 63±21* mg/min in the end. There was no statistically significant difference in carbohydrate oxidation between groups, and regarding lipids, the only statistically significant difference was between groups 1 (higher values, p=0,03) and 2 at the end of the experiment, and between groups 1 and 3 (higher values, p=0,04) at time 150´. In relation to the peptides, the baseline leptin was 47±29 ng/mL, decreasing to 44±27 ng/mL within the first postprandial 30´ and to 43±26 ng/mL in the end. Baseline ghrelin was 753±522 pg/mL, decreasing to 705±420 pg/mL in the first 30´ and to 561±343 pg/mL in the end. Baseline peptide YY was 92±40* pg/mL, increasing to 153±63* pg/mL in the first 30´ and to 214±66* pg/mL in the end. Referring to cholecystokinin, the value at 30´ was 1.8±2.3 pg/mL, increasing to 2.2±1.7 pg/mL in the end. Among groups, the only statistically significant difference was related to cholecystokinin between groups 2 and 3 (higher values, p=0,04) in the end. So, after the lipid overload, there was a gradual and significant increase on energy expenditure, predominance of carbohydrate oxidation in relation to the lipids with a decrease on its oxidation, and an increase on lipid oxidation. In regard to comparison between groups, there was no statistically significant difference in relation to energy expenditure, as well as to oxidation of carbohydrates and lipids in most of the time. The peptides leptin and ghrelin decreased after the lipid overload, while peptide YY and cholecystokinin increased, with no statistically significant difference between groups for most of the time. Thus, the variables were independent of plasma estradiol levels.

The previous view of DNA as a linear sequence of bases is evolving to consider structure, topology and dynamics. Sequences surrounding damage lesions have been shown to effect enzyme recognition and processing. Here we present an in depth investigation of subtle structural and dynamical features imparted to nucleic acid duplexes by a designed modification or damage lesions. Highly restrained solution structures were generated and validated utilizing a range of NMR techniques. This allowed for the characterization of multiple features of the nucleic acid duplex; such as base pairing, backbone torsion angles, deoxyribose sugar pucker, and intra and inter nucleotide proton distances. Additional experiments provided insight into dynamic movements of the nucleic bases. These features are then correlated to enzyme data in order to explain the observed modulation of activity.

The overall objective of this thesis was to examine mechanisms involved in the acute regulation of sarcoplasmic reticulum (SR) Ca2+-handling properties by second messenger signaling pathways in skeletal and cardiac muscle. The aim of the first study (Chapter Two) was to characterize changes in the kinetic properties of sarco(endo)-plasmic reticulum Ca2+-ATPase (SERCA) proteins in cardiac and skeletal muscles in response to b-adrenergic, Ca2+-dependent calmodulin kinase II (CaMKII) and protein kinase C (PKC) signaling. The aim of the second study (Chapter Three) was to determine if insulin signaling could acutely regulate SERCA kinetic properties in cardiac and skeletal muscle. The aim of the final study (Chapter Four) was to determine if alterations in plasma glucose, epinephrine and insulin concentrations during exercise are able to influence SR Ca2+-handling properties in contracting human skeletal muscle. Data collected in Chapter Two and Chapter Three were obtained using tissue prepared from a group of 28 male Sprague-Dawley rats (9 weeks of age; mass = 280 ± 4 g: X ± S.E). Crude muscle homogenates (11:1 dilution) were prepared from selected hind limb muscles (soleus, SOL; extensor digitorum longus, EDL; the red portion of gastrocnemius, RG; and the white portion of gastrocnemius, WG) and the left ventricle (LV). Enriched SR membrane fractions, prepared from WG and LV, were also analyzed. A spectrophotometric assay was used to measure kinetic properties of SERCA, namely, maximal SERCA activity (Vmax), and Ca2+-sensitivity was characterized by both the Ca50, which is defined as the free Ca2+-concentration needed to elicit 50% Vmax, and the Hill coefficient (nH), which is defined as the relationship between SERCA activity and Ca2+f for 10 to 90% Vmax. The observations made in Chapter Two indicated that b-adrenergic signaling, activated by epinephrine, increased (P<0.05) Ca2+-sensitivity, as shown by a left-shift in Ca50 (i.e. reduced Ca50), without altering Vmax in LV and SOL but had no effect (P<0.05) on EDL, RG, or WG. Further analysis using a combination of cAMP, the PKA activator forskolin, and/or the PKA inhibitor KT5270 indicated that the reduced Ca50 in LV was activated by cAMP- and PKA-signaling mechanisms. However, although the reduced Ca50 in SOL was cAMP-dependent, it was not influenced by a PKA-dependent mechanism. In contrast to the effects of b-adrenergic signaling, CaMKII activation increased SERCA Ca2+-sensitivity, as shown by a left-shift in Ca50 and increased nh, without altering SERCA Vmax in LV but was without effect in any of the skeletal muscles examined. The PKC activator PMA significantly reduced SERCA Ca2+-sensitivity, by inducing a right-shift in Ca50 and decreased nH in the LV and all skeletal muscles examined. PKC activation also reduced Vmax in the fast-twitch skeletal muscles (i.e. EDL, RG and WG), but did not alter Vmax in LV or SOL. The results of Chapter Three indicated that insulin signaling increased SERCA Ca2+-sensitivity, as shown by a left-shift in Ca50 (i.e. reduced Ca50) and an increased nH, without altering SERCA Vmax in crude muscle homogenates prepared from LV, SOL, EDL, RG, and WG. An increase in SERCA Ca2+-sensitivity was also observed in enriched SERCA1a and SERCA2a vesicles when an activated form of the insulin receptor (A-INS-R) was included during biochemical analyses. Co-immunoprecipitation experiments were conducted and indicated that IRS-1 and IRS-2 proteins bind SERCA1a and SERCA2a in an insulin-dependent manner. However, the binding of IRS proteins with SERCA does not appear to alter the structural integrity of the SERCA Ca2+-binding site since no changes in NCD-4 fluorescence were observed in response to insulin or A-INS-R. Moreover, the increase in SERCA Ca2+-sensitivity due to insulin signaling was not associated with changes in the phosphorylation status of phospholamban (PLN) since Ser16 or Thr17 phosphorylation was not altered by insulin or A-INS-R in LV tissue. The data described in Chapter Four was collected from 15 untrained human participants (peak O2 consumption, VO2peak= 3.45 ± 0.17 L/min) who completed a standardized cycle test (~60% VO2peak) on two occasions during which they were provided either an artificially sweetened placebo (PLAC) or a 6% glucose (GLUC) beverage (~1.00 g CHO per kg body mass). Muscle biopsies were collected from the vastus lateralis at rest, after 30 min and 90 min of exercise and at fatigue in both conditions to allow assessment of metabolic and SR data. Glucose supplementation increased exercise ride time by ~19% (137 ± 7 min) compared to PLAC (115 ± 6 min). This performance increase was associated with elevated plasma glucose and insulin concentrations and reduced catecholamine concentrations during GLUC compared to PLAC. Prolonged exercise reduced (p<0.05) SR Ca2+-uptake, Vmax, Phase 1 and Phase 2 Ca2+-release rates during both PLAC and GLUC. However, no differences in SR Ca2+-handling properties were observed between conditions when direct comparisons were made at matched time points between PLAC and GLUC. In summary, the results of the first study (Chapter Two) indicate that b-adrenergic and CaMKII signaling increases SERCA Ca2+-sensitivity in the LV and SOL; while PKC signaling reduces SERCA Ca2+-sensitivity in all tissues. PKC activation also reduces Vmax in the fast-twitch skeletal muscles (i.e. EDL, RG, and WG) but has no effect on Vmax in the LV and SOL. The results of the second study (Chapter Three) indicate that insulin signaling acutely increases the Ca2+-sensitivity of SERCA1a and SERCA2a in all tissues examined, without altering the Vmax. Based on our observations, it appears that the increase in SERCA Ca2+-sensitivity may be regulated, in part, through the interaction of IRS proteins with SERCA1a and SERCA2a. The results of the final study (Chapter Four) indicate that alterations in plasma glucose, epinephrine and insulin concentrations associated with glucose supplementation during exercise, do not alter the time course or magnitude of reductions in SERCA or Ca2+-release channel (CRC) function in working human skeletal muscle. Although glucose supplementation did increase exercise ride time to fatigue in this study, our data does not reveal an association with SR Ca2+-cycling measured in vitro. It is possible that the strength of exercise signal overrides the hormonal influences observed in resting muscles. Additionally, these data do not rule out the possibility that glucose supplementation may influence E-C coupling processes or SR Ca2+-cycling properties in vivo.

Nanoscience dominates virtually every field of science and technology in the 21st century. Nanoparticles are of fundamental interest since they possess unique size- dependent properties (optical, electrical, mechanical, chemical, magnetic etc.), which are quite different from the bulk and the atomic state. Bimetallic nanoparticles are of particular interest since they combine the advantages of the individual monometallic counterparts. The present study focuses on bimetallic nanoparticles containing gold as one of the constituents. Au-Pd, Au-Pt and Au-Ag bimetallic/alloy nanoparticles have been prepared by four different synthetic methods, and characterised by a variety of techniques, with an emphasis on Au-Ag alloy systems in the solution phase as well as in the form of nanostructured films on solid substrates. Au- Ag alloy nanoparticles have been used to demonstrate two different applications. The first is the use of Au-Ag monolayer protected alloy clusters in demonstrating single electron charging events in the solution phase as well as in the dry state. Single electron transfer events involving nanosized particles are being probed extensively due to their potential applications in the field of electronics. The second is an analytical application, involving the use of trisodium citrate capped Au-Ag alloy hydrosols as substrates for surface enhanced Raman and resonance Raman scattering [SE(R)RS] studies. The sols have been used for single molecule detection purposes. Various organic molecules such as quinones, phthalocyanines and methyl violet have been self- assembled in a stepwise manner on the nanoparticulate as well as bulk Au, Ag and Au-Ag surfaces, and characterised extensively by spectroscopic, electrochemical and spectroelectrochemical techniques.

This work refers to the area of bio-nanotechnology and concerns the selective immobilization of DNA or other bio-template on microstructured gold contacts and which then permit a coordinated cooperation of several of these nanotemplate, e.g., within a microreactor. The immobilization of such nano-objects should be realized through functional thin polymer films which provide binding groups. Thus, the main aim of this work was the development of polymeric materials for thin functional films which permit to deposit on different substrates a wide variation of functional elements or metal structures and to achieve a pattern formation using optical grid methods. In order to realize this concept it was necessary to design and develop a polymer system based on suitable photolabile units and in addition having anchoring groups which attach on specific substrates like gold. In this terpolymer concept was aimed for which consists of three components with particular functions in suitable molar ratios, which allow the tune the properties of the materials, and provide: amino photolabile protected groups for the photolithographic creation of patterned areas with free amino groups, which are available for further modifications like attachment of colloids, metallization or attachment of DNA strands; disulfide derivative anchor groups providing anchoring capacity for gold surface and spacer groups for adjusting the film quality. These multifunctional terpolymers should be synthesised by free radical polymerisation of suitable monomers. Although these techniques are successful, they are limited by their complexity, rigorous synthetic demands, as well as incompatibility with many functional termolabile and highly reactive functionalities. To overcome these difficulties a polymerisation technique based on “living” free radical polymerisation has been used in this work. A highly efficient polymer-analogous modification allows to introduce the functionalities after the polymer construction reaction. The production of suitable prepolymers [poly(styrene-r-4-propargyl-oxystyrene)] was carried out with the help of a controlled synthesis methodology “nitroxide mediate radical polymerization&amp;quot; followed by polymer analogous reaction using one of the most efficient click reactions, the Cu(I) catalyzed Huisgen 1,3-dipolar cycloaddition between terminal acetylenes and azides to attach further functionalities through the formation of a stable 1,4-disubstituted 1,2,3-triazol ring . The combination of nitroxide mediated radical polymerization (NMRP) and click chemistry was used to produce well-defined random copolymer. It could already be shown that also block copolymers can be prepared which give the chance to combine nanostructure formation in block copolymers with special functionality. Thus, the special properties of these functional polymers like the capability for photopatterning and anchoring onto gold substrates make them very interesting for nanotechnology applications. / Diese Arbeit bezieht sich auf das Gebiet der Bionanotechnologie und betrifft ein neuartiges Verfahren zur selektiven Immobilisierung der DNA oder anderer Biomoleküle auf mikrostrukturierten Goldkontakten, welche dann ein koordiniertes Zusammenwirken von einzelnen Nanomolekülen ermöglichen, z.B. in einem Mikroreaktor. Die Immobilisierung solcher Nanoobjekte soll durch dünne Funktionsschichten realisiert werden, die die Anbindungsgruppen liefern. Folglich war das Hauptziel dieser Arbeit die Entwicklung von Polymermaterialien für dünne Funktionsschichten, die die Aufbringung einer großen Vielzahl von Funktionselementen oder metallischen Strukturen auf verschiedenen Substraten gestatten und die Strukturierung durch den Einsatz von lithographischen Methoden ermöglichen. Um dieses Konzept zu realisieren, war es notwendig, ein Polymersystem zu gestalten und zu entwickeln, welches auf geeignete photolabile Einheiten basiert und zusätzlich Ankergruppen hat, die mit spezifischen Substraten wie Gold verbunden ist. Dieses Terpolymerkonzept wurde gezielt aus drei Komponenten mit speziellen Funktionen in entsprechenden molaren Verhältnissen gebildet, die eine Abstimmung der Materialeigenschaften ermöglicht und folgendes bereitstellt: photolabile geschützte Aminogruppen für die photolitographische Strukturerzeugung mit freien Aminogruppen, welche für weitere Modifikationen verfügbar sind wie das Anhängen von Kolloiden, die Metallisierung oder Anfügung von DNA-Strängen; disulfide Derivate für die kovalente Anbindung auf der Goldoberfläche und Spacer-Gruppe für Verbesserung der Schichtenbildung. Diese multifunktionalen Terpolymere sollen durch eine freie radikalische Polymerisation von entsprechenden Monomeren synthetisiert werden. Obwohl diese Techniken erfolgreich sind, sind sie eingeschränkt durch ihre Komplexität, den strengen synthetischen Anforderungen, sowie der Inkompatibilität mit vielen funktionalen thermolabilen und hochreaktiven Funktionalitäten. Um diese Schwierigkeiten zu überwinden wurde eine Polymerisationstechnik für diese Arbeit genutzt, die auf der „lebenden“ freien radikalischen Polymerisation basiert. Eine hoch effiziente polymeranaloge Modifizierung erlaubt die Einführung von Funktionalitäten nach der Polymeraufbaureaktion. Die Herstellung von entsprechenden Präpolymeren Poly(Styrol-r-4-Propargyl-oxystyrol) wurde mittels einer kontrollierten Synthesemethodik „Nitroxid-mediated controled radical polymerisation“ (NMRP) durchgeführt, gefolgt von der Polymeranalogreaktion, die eine der effizientesten Click-Reaktion - die Cu(I) katalysierte 1,3-dipolar Cycloaddition von terminalen Alkinen an Aziden nach Huisgen nutzt, um weiter Funktionalitäten durch die Bildung eines stabilen 1,4-disubstituierten-[1,2,3]-Triazolringes anzufügen. Die Kombination von NMRP und Click-Chemie wurde zur Herstellung eines exakt definierten Random Copolymers genutzt. Es konnte bereits gezeigt werden, dass auch Blockcopolymere geschaffen werden können, die eine Möglichkeit zur Kombination von Nanostrukturformationen in Blockcopolymeren mit speziellen Funktionaltäten bieten. Folglich sind die speziellen Eigenschaften dieser Funktionalpolymere wie die Fähigkeit zur Photostrukturierung und Verankerung auf Goldsubstraten für nanotechnologische Anwendungen sehr interessant.

This thesis deals with the transport properties and critical current limitations found in YBa2Cu3O7[-delta] coated conductors prepared by the &amp;quot;rolling assisted biaxially textured substrate&amp;quot; (RABiTS) approach. For this purpose a buffer layer system composed of CeO2 and yttria-stabilised zirconia, and subsequently a YBa2Cu3O7[-delta] film were epitaxially grown by pulsed laser deposition on a biaxially textured metallic substrate. The resulting texture of the YBa2Cu3O7[-delta] film is crucial for the achievement of high critical current densities. A propagation of the granular structure of the metallic substrate into the YBa2Cu3O7[-delta] film was detected, which leads to the formation of a YBa2Cu3O7[-delta] grain boundary network and limits the critical current density of the samples. In order to study this limitation, critical current measurements were performed on the prepared samples at different temperatures and magnetic fields, detecting a transition between intergrain and intragrain current limitation that occurs at the so-called crossover magnetic field. The crossover magnetic field was found to shift to lower values as the temperature was increased. It was concluded that the grain boundary network limits the critical current density of the YBa2Cu3O7[-delta] coated conductor only for magnetic fields below the crossover field. / In der vorliegenden Dissertation werden Transporteigenschaften und die Limitierung der kritischen Stromdichte von YBa2Cu3O7[-delta] Bandleitern untersucht. Für die Präparation wird das epitaktische Schichtwachstum auf biaxial texturierten Substraten genutzt (RABiTS-Technik). Dabei wird mittels gepulster Laserdeposition eine Pufferschicht aus CeO2 und Yttrium-stabilisiertem Zirkonoxyd (YSZ) und anschließend eine YBa2Cu3O7[-delta] Schicht epitaktisch auf ein Substrat aufgebracht. Die resultierende biaxiale Textur der YBa2Cu3O7[-delta]-Schicht spielt eine Hauptrolle, um möglichst hohe Stromdichten zu erreichen. Es zeigte sich, daß die granulare Struktur des Substrates in die YBa2Cu3O7[-delta]-Schicht übertragen wird und zur Ausbildung eines Korngrenzennetzwerkes führt, welches wiederum die zu erwartende kritische Stromdichte begrenzt. Um die Wirkung des Korngrenzennetzwerkes zu untersuchen, wurden kritische Ströme der gewachsenen Schichten in Abhängigkeit der Temperatur und des angelegten Magnetfeldes gemessen. Es stellte sich heraus, daß die Limitierung des Stroms bei schwachen Magnetfeldern zwischen den einzelnen Körnern bestimmend ist, die dann bei größeren Feldern einer Strombegrenzung innerhalb der Körner weicht. Das beide Bereiche trennende Magnetfeld wird als Übergangsfeld bezeichnet. Daraus kann geschlußfolgert werden, daß das Korngrenzennetzwerk von YBa2Cu3O7[-delta] Bandleitern den Strom nur für magnetische Felder unterhalb des Übergangsfeldes begrenzt.

Στην παρούσα εργασία, η αποθήκευση υδρογόνου σε νανοσωλήνες άνθρακα εξετάστηκε με τη βοήθεια δύο πειραματικών τεχνικών: ρόφηση υδρογόνου και θερμοπρογραμματιζόμενη εκρόφηση υδρογόνου. Τα δείγματα που εξετάστηκαν για αποθήκευση υδρογόνου περιελάμβαναν MWCNTs, thinMWCNTs και SWCNTs. Τα πειράματα ρόφησης υδρογόνου πραγματοποιήθηκαν σε θερμοκρασία 298 Κ και σε εύρος πίεσης 0-1000 Torr και τα αποτελέσματα που προέκυψαν είναι, 0.12-0.17 wt.%, 0.22 wt.% καιι 0.30-0.36 wt.% αντίστοιχα. Τα αποτελέσματα που προέκυψαν από τους υπολογισμούς της ενέργειας ενεργοποίησης εκρόφησης (~20 kJ/mol) των TPD πειραμάτων οδήγησαν στο συμπέρασμα ότι η αποθηκευτική ικανότητα Η2 των CNTs δεν είναι αποτέλεσμα μόνο φυσικής ρόφησης, αλλά και φαινόμενα χημικής ρόφησης λαμβάνουν χώρα και ότι η διαθέσιμη προς ρόφηση Η2 επιφάνεια των CNTs είναι ομοιόμορφη, αφού η ποσότητα Η2 που ροφήθηκε στους CNTs στους 298 Κ, εκροφήθηκε από αυτούς στην ίδια θερμοκρασία. Η ενίσχυση της ικανότητας ρόφησης Η2 ενός υλικού, λαμβάνει χώρα μέσω του φαινομένου spillover. Pt εναποτέθηκε στους CNTs μέσω υγρού εμποτισμού ή μέσω ανάμιξης στη συσκευή υπερήχων του αιωρήματος των CNTs στο διάλυμα της πρόδρομης ένωσης. Στους CNTs που εξετάστηκαν, η παρουσία Pt στην επιφάνεια τους, σχεδόν διπλασίασε την αποθηκευτική τους ικανότητα σε Η2. Οι εμπλουτισμένοι με αλκάλια CNTs εμφανίζουν μεγαλύτερα ποσοστά αποθήκευσης Η2 από τους μη εμπλουτισμένους. Η συμπεριφορά αυτή έχει αποδοθεί στη δημιουργία δίπολου πάνω στο μόριο του Η2, λόγω της ύπαρξης σημειακών φορτίων στα αλκάλια. Το μέγιστο ποσοστό αποθήκευσης που επιτεύχθηκε στην παρούσα εργασία είναι το 0.7 wt.%, στους 298 Κ, για το υλικό 0.5% Pt/ Li(5%)-SWCNTs-85%. Στα κελιά καυσίμου ΡΕΜ, το μεγάλο κόστος λόγω της παρουσίας του καταλύτη Pt στα ηλεκτρόδια τους, αποτελεί τον κυριότερο περιορισμό για την εμπορευματοποίηση τους. Ως εκ τούτου, στόχος είναι η αποδοτικότερη χρήση του καταλύτη Pt με ταυτόχρονη μείωση της ποσότητας του. Στην παρούσα εργασία μελετήθηκαν, μέσω ηλεκτροχημικών πειραμάτων, οι καταλύτες Pt/SWCNTs, Pt/MWCNTs και Pt/Vulcan-XC72. Η εναπόθεση της Pt έλαβε χώρα με τις προαναφερθείσες μεθόδους, και τα αποτελέσματα των πειραμάτων έδειξαν ότι τόσο η μέθοδος εναπόθεσης Pt, όσο και το είδος των CNTs, επηρεάζουν τα ηλεκτροχημικά χαρακτηριστικά των ηλεκτροδίων. Μέγιστη παραγόμενη ισχύς της τάξης των 0.21 W/cm2, επιτεύχθηκε με τους καταλύτες Pt/SWCNTs με χρήση τους ως ηλεκτρόδιων ανόδου. / In this study, hydrogen storage on carbon nanotubes was studied via two main methods: hydrogen adsorption and temperature programmed desorption. CNTs (multi-walled, thin multi-walled and single walled) of variable purity were tested for their hydrogen adsorption capacity at 298 in the pressure range of 0 to 1000 Torr. Maximum adsorption capacity per unit mass of the solid was observed over SWCNTs (0.30-0.36 wt.%), followed by thinMWCNTs (0.22 wt.%) and MWCNTs (0.12-0.17 wt.%). Temperature programmed desorption revealed that the adsorption sites on the CNTs surface are relatively uniform, due to the fact that the quantity of hydrogen desorbed is very close to the quantity of hydrogen adsorbed. The calculated values of desorption activation energy (~20 kJ/mol) revealed that adsorption on CNTs is not purely physical in nature but it also involves weak chemisorption bonds. One potential way to enhance hydrogen storage on carbon nanotubes is spillover effect. Pt was deposited on CNTs via wet impregnation (method A) or mixture of the suspension of carbon nanotubes in the solution of the precursor under sonication (method B). Both, hydrogen adsorption experiments at 298 K and temperature programmed desorption measurements revealed that hydrogen storage capacity observed over CNTs was almost double. Experimental and theoretical researches have shown that alkali doped CNTs presented higher values of hydrogen storage capacity, compared to non alkali doped CNTs. This behavior has been attributed to the creation of bipolar forces in the hydrogen molecule, due to the charge transfer in alkalis. The highest storage capacity presented in this work was 0.7 wt.%, for Li doped CNTs when Pt was deposited on them via method B. The use of CNTs as platinum support for proton exchange membrane fuel cells has been investigated as a way to reduce the cost of fuel cells through an increased utilization of platinum. This work presents results with Pt catalysts supported on CNTs and also on commonly used carbon powder, Vulcan XC-72, prepared via methods mentioned above. The results indicate electrochemical characteristics which depend strongly on the nature of the support and the Pt deposition method. Power density of 0.21 W/cm2 at 80 0C was achieved with Pt/SWCNTs fed with H2 and the activity of the anodes followed the sequence: Pt/SWCNTs > Pt/MWCNTs > Pt/Vulcan XC-72.