Primary open angle glaucoma (POAG) is a leading cause of blindness worldwide. Elevated intraocular pressure (IOP), resulting from increased aqueous humor outflow resistance, is a major risk factor for the development and progression of POAG. Outflow resistance in the trabecular outflow pathway is mainly (50-75%) generated in the juxtacanalicular connective tissue (JCT), and partially (25-50%) in the portion distal to the inner wall of Schlemm’s canal. The details of how aqueous humor flows through these tissues and how resistance in these tissues is regulated are not fully understood in normal and POAG eyes. Aqueous humor outflow was shown to be “segmental”, with discontinuous active regions of aqueous humor filtration along the trabecular outflow pathway that can be labeled with perfused fluorescent tracers and measured as effective filtration area (EFA). In this study, we investigated the relationship between changes in EFA along the trabecular outflow pathway and outflow facility/IOP under two experimental conditions. The first experiment was designed to increase outflow facility by using netarsudil, a recently approved Rho kinase inhibitor class glaucoma medication, in normal human donor eyes. The second experiment was designed to increase IOP with topical steroid treatment for 5 weeks in mice. The purpose of this study is to verify whether EFA can be modulated by netarsudil or steroid treatment and to demonstrate the morphological changes that may be responsible for the changes of EFA. We analyzed EFA along the trabecular outflow pathway and found that elevated/reduced EFA correlated with increased outflow facility/IOP. Guided by EFA, we performed detailed morphological comparison between the active and inactive portions of aqueous humor filtration tissue to evaluate possible structural changes involved in EFA regulation. We found that increased EFA was associated with a loosened JCT structure and dilated episclearal veins, while decreased EFA was associated with a compacted JCT structure, increased deposition of curly collagen and/or fibrillary structure in the trabecular meshwork, and increased basement membrane continuity. Our data suggest that the netarsudil/steroid-induced morphological changes in the trabecular outflow pathway can result in either an increase or decrease in EFA, which in turn contributes to the regulation of outflow facility/IOP. / 2020-10-24T00:00:00Z

Les chondrites carbonées de type 1 et 2 comprennent les météorites les plus primitives d’un point de vue chimique et pétrologique. Ce caractère primitif est associé à l’abondance de matière organique qui est une phase privilégiée pour l’étude des phénomènes concernant l’héritage du matériel présolaire et sa transformation dans la nébuleuse puis sur les premiers corps. L’objet de cette thèse est l’étude de l’influence des processus post-accrétionnels sur les caractéristiques moléculaires de la matière organique et en particulier la mesure des effets d’oxydation dus à l’altération aqueuse. Nous avons mené une étude comparative basée sur la structure carbonée et l’analyse des fonctions oxygénées et soufrées d’une dizaine de météorites dont les histoires géologiques ont été déterminées par ailleurs. Le degré d’oxydation du soufre, hétéroatome mineur dans la fraction insoluble, a été mesuré par micro-spectrométrie SK-Xanes. La spectroscopie FT-IR a permis la description des structures fines des chaines carbonées et des fonctions riches en oxygène, hétéroatome majeur. La spectrométrie de masse à très haute résolution Orbitrap a été utilisée pour décrire la diversité hétéroatomique des molécules solubles de la chondrite Renazzo (CR2). Les chaines carbonées des chondrites de classe CI et Murchison se différencient de celle des autres météorites par une abondance en groupements terminaux méthyles à la fois supérieure et invariable. Les chondrites de type 1 sont les seules porteuses de fonctions soufrées oxydées acides alors que la spéciation du soufre dans les chondrites de type 2 est invariable. De la même façon, et cette fois pour l’ensemble des chondrites étudiées, les groupements carbonyles sont majoritairement dans les fonctions cétones, en proportion indépendante du degré d’altération aqueuse. Tous les paramètres mesurés dans cette étude nous poussent à conclure que la variabilité moléculaire au sein des chondrites carbonées de type 1 et 2 trouve moins son origine dans l’empreinte de l’hydrothermalisme que dans une hétérogénéité du précurseur organique accrété par chaque corps parent. En particulier, nos mesures invalident l’hypothèse selon laquelle l’altération serait à l’origine d’une conversion oxydative des chaines carbonées en fonctions acides carboxyliques. / Type 1 and 2 carbonaceous chondrites include the most chemically and petrologically pristine meteorites. This intactness goes along with the abundance of organic matter which is a phase of choice to investigate the presolar material processing in the nebula and then on the first bodies. The purpose of this thesis is to study the influence of post-accretional processes on the molecular characteristics of organic matter and in particular the extent of oxidation effects due to aqueous alteration. We have carried out a comparative study based on the carbon structure and functional analysis of more than ten meteorites whose geologic histories were independently determined. The redox degree of sulfur in the insoluble fraction was measured by SK-Xanes spectroscopy. FT-IR spectroscopy gave access to the fine structures of aliphatic chains and oxygen-rich functions. Orbitrap very high resolution mass spectrometry was used to describe the heteroatomic diversity of soluble molecules in the Renazzo (CR2) chondrite. The aliphatic chains of CI chondrites and Murchison differ from others by a higher and unchanging abundance of methyl groups. Type 1 chondrites are the only carriers of oxidized sulfur functions whereas the sulfur speciation in type 2 chondrites is invariable. For all studied chondrites, the carbonyl groups are mainly under the form of ketones and their abundance can’t be related to the degree of aqueous alteration. Any parameters we have measured in this study lead us to conclude that the molecular variability among type 1 and 2 carbonaceous chondrites are less due to the footprint left by the hydrothermal activity than due to the heterogeneity of an organic precursor accreted by each parent body. In particular, our measurements invalidate the hypothesis that the alteration would cause an oxidative conversion of aliphatic chains to carboxylic acid functions.

Data de aprova??o retirada da vers?o impressa do trabalho. / Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2018-01-04T19:50:32Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) edgard_ronny_delgado_huamani.pdf: 5898825 bytes, checksum: 78eee370de5fed297b3181e82d98f63d (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2018-01-17T18:40:25Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) edgard_ronny_delgado_huamani.pdf: 5898825 bytes, checksum: 78eee370de5fed297b3181e82d98f63d (MD5) / Made available in DSpace on 2018-01-17T18:40:25Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) edgard_ronny_delgado_huamani.pdf: 5898825 bytes, checksum: 78eee370de5fed297b3181e82d98f63d (MD5) Previous issue date: 2017 / Neste trabalho, Carbon Dots (CD) oxidados foram preparados a partir de rea??es de desidrata??o/oxida??o ?cida da celulose, e posteriormente desoxigenados em meio alcalino e rea??o com sulfato de hidrazina. As caracteriza??es dos CD foram feitas com Microscopia eletr?nica de Transmiss?o, FTIR, titula??o potenciom?trica, Resson?ncia Magn?tica Nuclear de 13C e espectroscopia UV-Vis e fluoresc?ncia. Os resultados obtidos com estas caracteriza??es mostraram que a amostra oxidada apresenta um tamanho m?dio aproximadamente de 2,7 nm com uma significativa quantidade de grupos funcionais oxigenados ?cidos, dos quais 63% s?o ?cidos carbox?licos. Ap?s as rea??es de modifica??o superficial foi verificado que em meio alcalino ocorre somente uma elimina??o de nanoestruturas mais oxidadas, enquanto que na rea??o com hidrazina ocorre a redu??o de alguns grupos carbox?licos e ep?xidos com forma??o de grupos funcionais hidrazonas. Como consequ?ncia da modifica??o superficial, as propriedades ?pticas dos CD s?o alteradas significativamente. Com a redu??o, o band gap diminui e a energia da emiss?o aumenta, deslocando-se para a regi?o azul do espectro eletromagn?tico. Uma vez caracterizados, a parti??o de todos os CD preparados foi investigada em diferentes Sistemas Aquosos Bif?sicos (SAB), nos quais foram avaliados os efeitos dos c?tions e ?nions dos sais, dos pol?meros e do pH inicial do sistema no coeficiente de parti??o (K). Em adi??o foi avaliado o efeito da modifica??o superficial das nanopart?culas. A rela??o do K com comprimento da linha de amarra??o (CLA), o par?metro termodin?mico dos SAB foi estudado para todos os sistemas. Os resultados obtidos mostraram que a melhor separa??o ocorreu com o sistema PEO1500+sulfato de l?tio+?gua em pH=3 e usando os Carbon Dots reduzidos com hidrazina. O valor do K para este sistema foi de 64,4. Por outro lado, o menor valor de K foi 0,79, foi obtido para o sistema PEG1500+tartarato de s?dio+?gua em pH=6 e usando Carbon Dots oxidados. As an?lises detalhadas das fases superior e inferior de alguns destes sistemas com espectroscopia de fluoresc?ncia mostraram que os SAB s?o capazes, al?m de particionar, separar as nanopart?culas com diferentes propriedades ?pticas, as quais est?o diretamente associadas ?s propriedades superficiais e tamanho de part?culas. Por fim, n?s avaliamos a atividade catal?tica foto-Fentom dos CD na degrada??o do corante ani?nico ?ndigo de carmim e os resultados mostraram que os CD apresentam atividade fotocatal?tica neste sistema. Devido ? alta parti??o verificada para o sistema PEG1500+ sulfato de l?tio+?gua, este foi usado para avaliar a potencialidade de seu uso em cat?lise de transfer?ncia de fase usando CD como fotocatalisador e o corante ?ndigo de carmim como mol?cula modelo. Apesar da complexidade e da dificuldade de caracteriza??o dos produtos da foto-oxida??o no SAB, os resultados obtidos indicam que o sistema testado pode ser usado em rea??es de transfer?ncia de fase fotocatalisadas. Como conclus?o final, acredita-se que os resultados apresentados, em especial, a parti??o/sele??o das nanopart?culas com distintas propriedades ?pticas s?o de extrema import?ncia para o desenvolvimento de novas e eficazes aplica??es dos CD. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Qu?mica, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2017. / In this work, oxidized Carbon Dots (CD) were prepared by a dehydration/oxidation reaction of cellulose and subsequently deoxygenated in alkaline medium and reaction with hydrazine sulfate. The CD characterizations were made with Transmission Electron Microscopy, FTIR, potentiometric titration. 13C Nuclear Magnetic Resonance, UV-Vis and fluorescence spectroscopy. The results obtained with these characterizations showed that the oxidized sample has an average size of 2.7 nm with a significant amount of acid oxygenated functional groups, of which 63% are carboxylic acids. After the superficial modification reactions, it was verified that in alkaline conditions only one elimination of more oxidized nanostructures occurs, whereas in the reaction with hydrazine the reduction of some carboxylic groups and epoxides with formation of hydrazones functional groups. As a consequence of the surface modification, the optical properties of the CD are significantly changed. The band gap decreases and the emission energy increases, shifting to the blue region of the electromagnetic spectrum. Once characterized, the partitioning of all CD prepared was investigated in differente Aqueous two-phase systems (ATPS), in which the effects of the cations and anions of salts, of the polymers and the initial pH of the system in the partition coefficient (K) were evaluated. In addition, the surface modification effect of the nanoparticles was evaluated. The relationship of K with Tie Line Length (TLL), the thermodynamic parameter of the ATPS was studied for all systems. The results showed that the best separation occurred with the system PEO1500 + lithium sulfate + water at pH = 3 and using the reduced carbon dots with hydrazine. The K value for this system was 64,4. On the other hand, the lowest K value was 0,79, it was obtained for the system PEG1500 + sodium tartrate + water at pH = 6 and using oxidized carbon dots. The detailed analysis of the upper and lower phases of some of these systems with fluorescence spectroscopy showed that the ATPS are capable, in addition to partition, to separate the nanoparticles with different optical properties, which are associated directly to the surface properties and particle size. Finally, we evaluated the photo-Fentom catalytic activity of the CD in the degradation of the anionic anion dye indigo carmine and the results showed that the CD present photocatalytic activity in this system. Due to the high partition found for the PEG1500 + lithium + water sulfate system, it was used to evaluate the potentiality of its use in phase transfer catalysis using CD as a photocatalyst and the indigo carmine dye as a model molecule. Despite the complexity and difficulty of characterizing the photo-oxidation products in ATPS the results indicate that the system tested can be used in photocatalysed phase transfer reactions. As a final conclusion, we believe that the results presented, in particular, the partitioning / selection of nanoparticles with different optical properties are of extreme importance for the new and effective applications of CD.

Neste trabalho estudou-se o desenvolvimento de metodologia analitica para a determinação e quantificação de sete anti-inflamatórios não esteroides, amplamente consumidos para tratamento humano, além da cafeína, determinada como marcador antropogênico, em amostras aquosas ambientais. Os analitos estudados foram acetaminofeno (AC), ácido salicílico (AS), cafeína (CA), cetoprofeno (CE), diclofenaco (DC), dipirona (DP), ibuprofeno (IB) e naproxeno (NA) . Como padrão internos, foi utilizado o lindano (LI). A determinação destes analitos foi realizada utilizando-se cromatografia a gás acoplada à espectrometria de massas (GC-MS) utilizando MSTFA/Imidazol como derivatizante. As condições para a reação de derivatização foram otimizadas utilizando o planejamento Doehlert. O procedimento de pré-concentração utilizado foi a extração em fase sólida (SPE), tendo como sorvente um sistema de fase polimérica reversa. O procedimento de SPE foi baseado em trabalhos publicados na literatura, com metanol e água (ajustada a pH 3,0) para o condicionamento e eluição com acetonitrila. Os parâmetros de desempenho do método, como recuperação, linearidade, limite de detecção, limite de quantificação, repetitividade e reprodutibilidade foram avaliados de acordo com as normas estabelecidas pela ANVISA e INMETRO. Os limites de detecção ficaram entre 1,09 e 1079,14 ng L-1 e os de quantificaçõ entre 3,63 e 3597,12 ng L-1. Após as definições em relação ao método, amostras de água do Arroio Dilúvio (em Porto Alegre – RS) e de uma Estação Piloto de tratamento de efluente pertencente ao Instituto de Pesquisas Hidráulicas (IPH/UFRGS) , foram analisadas para avaliar a presença destes analitos. As amostras da ETE-piloto do IPH, foram coletadas nos meses de janeiro e fevereiro e as amostras do Arroio Dilúvio também foram coletadas no mesmo período. Considerando as amostras reais analisadas em algumas foram detectados e em outras quantificados os antiinflamatórios estudados. Nas amostras que estes compostos foram quantificados, a faixa de concentração variou entre 0,09 e 23,16 μg L-1. / In this work the development of an analytic methodology was studied to determine and quantify seven non-steroidal anti-inflammatory drugs, widely used in human treatment, and caffeine considered an anthropogenic marker. The compounds studied were acetaminophen (AC), salicylic acid (AS), caffeine (CA), ketoprofen (CE), diclofenac (DC), dipyrone (DP), ibuprofen (IB), naproxen (NA) and lindane (LI) as internal standard. The determination of these compounds was performed using gas chromatography coupled to mass spectrometry (GC-MS) with derivatization of the target analytes using MSTFA/Imidazole. The derivatization conditions were optimized with Doehlert design. Solid phase extraction (SPE) with a polymeric reversed solid phase was used as a pre-concentration system. The SPE procedure conditions were based previously established data in the literature, using methanol and water (adjusted to pH 3.0) for the conditioning step and acetonitrile for the elution step The performance parameters, such recovery, linearity, detection limit, quantification limit, repeatability and reproducibility were evaluated according to ANVISA and INMETRO determinations. The detection limits was in the range of 1,09 and 1079,14 ng L -1 and the quantification limits 3,63 and 3597,12 gn L-1. After method establishment, samples from a piloto sewage treatment plant and river water, both in Porto Alegre-RS, were analysed. The samples were collected in January and February 2012, both in the pilot plant and in the river water. In some real samples the antiinflammatories were detected and in others was possible quantify. In the samples were the analytes were quantified, the concentration range was 0,09 to 23,16 μg L-1.

Les pièces en aluminium sont largement utilisées dans le domaine aéronautique en raison de leurs bonnes propriétés mécaniques. Mais elles nécessitent un traitement de surface pour améliorer leur tenue en corrosion. Soumises à de nouvelles normes sur l'utilisation de produits chimiques et à la prise de conscience de la protection environnementale et humaine, les industries aéronautiques doivent à présent impérativement remplacer les procédés de traitements de surface actuels, devenus obsolètes car incluant des composés CMR. L'objectif de ces travaux de recherche est de développer un traitement de surface par voie liquide, à la fois innovant et conforme à la législation REACH, pour améliorer les propriétés d'anticorrosion des alliages d'aluminium ; le procédé d'élaboration présentement étudié, est composé d'une anodisation poreuse puis d'un colmatage par imprégnation de particules au sein des pores. Un film anodique poreux " modèle " a tout d'abord été élaboré et caractérisé : son épaisseur est de 10 µm, tandis que les pores sont rectilignes et ont un diamètre moyen de 120 nm. Puis, nous avons étudié la synthèse par voie aqueuse, de nanoparticules de boehmite, l'optimisation des différents paramètres de synthèse ayant permis finalement d'obtenir des particules d'une taille inférieure à celle des pores du film anodique. Deux techniques d'incorporation ont ensuite été expérimentées : le trempage-retrait et l'électrophorèse. La compréhension des mécanismes mis en jeu et de l'influence de différents paramètres opératoires, a permis une maitrise des procédés et l'insertion effective de particules. Des caractérisations microstructurales ont en particulier montré que l'insertion de particules est plus aisée dans le cas d'une électrophorèse avec une tension pulsée. Enfin, la mise en œuvre d'un post-traitement hydrothermal après l'imprégnation, a permis d'obtenir un colmatage complet des pores du film anodique, et d'augmenter significativement les propriétés anticorrosion. / Aluminum parts are widely used in the aeronautical field because of their good mechanical properties. But they require a surface treatment to improve their resistance to corrosion. Subject to new standards on the use of chemicals and awareness of environmental and human protection, the aeronautical industry must now replace current surface treatment processes, which have become obsolete because they include CMR compounds. The aim of this research is to develop a surface treatment, both innovative and REACH compliant, to improve the anticorrosion properties of aluminum alloys; the process here studied, is composed of a porous anodization and a sealing by impregnation of particles within the pores. A "model" porous anodic film was first prepared and characterized: its thickness is 10 µm, while the pores are straight and have a mean diameter of 120 nm. Then, we studied the aqueous synthesis of boehmite nanoparticles; the optimization of the synthesis parameters finally allowed to obtain a particle size smaller than the pore diameter. Two incorporation techniques were then tested: dip-coating and electrophoresis. The understanding of the involved mechanisms and of the influence of different operating parameters, allowed a control of the processes and the effective insertion of particles. In particular, microstructural characterizations showed that the particle insertion is easier using pulsed voltage electrophoresis. Finally, a hydrothermal post-treatment after the impregnation, allowed to obtain a complete sealing of the anodic film pores, and to significantly increase the anticorrosion properties.

Inorganic nanoscale clusters have garnered significant interest for many practical applications within the fields of materials chemistry, inorganic chemistry, geochemistry, and environmental chemistry. However, the fundamental inner workings of how these materials interact in the solid state and solution continues to be a very elusive problem for scientists. My dissertation focuses on taking non-traditional approaches and characterization techniques to further understand the dynamic interactions of some of the aforementioned clusters. Chapter I is a comprehensive survey and perspective on selected characterization techniques used to study Group 13 aqueous nanoscale clusters and other polyoxometalates in solution. Chapter II focuses on utilizing Raman spectroscopy, infrared spectroscopy, and quantum mechanical computations to unambiguously identify Group 13 tridecameric species in the solid state and aqueous solution. Chapter III discusses the first instance of transmetalation of aqueous aluminum clusters via salt addition of In(NO3)3 in aqueous or methanol. Chapters IV and V explore the effects that aprotic and protic solvents can have on the solution speciation of the flat aluminum tridecamer. Chapter VI discusses the utility of using electrochemically synthesized gallium tridecamer and its functional use as a thin film semiconductor. Chapter VII describes a unique graduate level chemistry course designed to allow students to conduct and generate publication-worthy research within the timeframe of the course. Chapter VIII ventures out beyond the group 13 cluster and introduces techniques used to study the formation and stability of aqueous hafnium clusters. Chapter IX details the synthesis and characterization of rhombic structured copper clusters in the solid state. Finally, chapter X highlights my unfinished projects that can propel future research within the lab. This dissertation includes previously published and unpublished co-authored material.

Un des objectifs majeurs de la neuroimagerie moderne est l'identification de nouveaux marqueurs qui puissent aider au diagnostic et au suivi des pathologies neurologiques. L'imagerie par résonnance magnétique multimodale (IRMm) est une approche permettant l'évaluation de plusieurs biomarqueurs complémentaires au cours d'un seul examen d'IRM. Cette approche a montré son efficacité dans de nombreuses études récentes et notamment dans la maladie de Parkinson. A l'approche IRMm précédemment utilisée, nous avons introduit un nouveau biomarqueur i.e. les changements de forme des structures sous-corticales à partir d'images pondérées en T1. Ce dernier marqueur vient enrichir l'approche IRMm composée de la quantification de : (i) la volumétrie à partir d'images pondérées en T1 (ii) de l'intégrité et l'orientation microstructurales à partir des images pondérées en diffusion et (iii) des dépôts de métaux à partir de la relaxométrie T2*. Nous avons appliqué l'approche IRM multimodale à une autre maladie neurodégénérative, la maladie d'Alzheimer à un stade précoce. Les résultats de cette étude préliminaire nous ont permis de suggérer la présence de processus physiopathologiques différents à la phase prodromique de la maladie d'Alzheimer. En effet nous avons observé pour l'hippocampe et l'amygdale une atrophie avec modification de l'intégrité microstructurale alors que seule une atrophie a été observée pour le thalamus et le putamen. Ces résultats nous ont aussi permis de confirmer l'importance d'une approche multimodale pour les études portant sur les maladies neurodégénératives. Parmi les marqueurs de l'IRMm, la quantification du fer intracérébral par relaxométrie T2* est une des méthodes qui a été développé ces dernières années à l'unité Inserm U825. Le dérèglement du métabolisme du fer et son accumulation sont en effet impliqués dans la physiopathologie de nombreuses maladies neurodégénératives telles que la maladie de Parkinson. L'expérience acquise à travers les différentes validations cliniques de cette méthode ces dernières années nous a conduit à améliorer cette dernière. Nous avons dirigé nos travaux sur l'amélioration de la méthode de relaxométrie R2* en optimisant l'acquisition d'une part et le traitement des images d'autre part. Nous avons donc comparé différentes résolutions, antennes, facteurs d'accélération, et nombres d'acquisitions par temps d'écho afin de déterminer les paramètres permettant d'obtenir le plus haut rapport signal sur bruit. Pour la partie traitement des images nous avons comparé la méthode utilisée comme référence, la méthode des moindres carrés par algorithme de Levenberg-Marquardt, à une autre méthode, la décomposition en valeur singulière pour estimer avec le plus de justesse le taux relaxation R2*. Nous avons ainsi pu mettre au point une séquence de relaxométrie T2* optimisée que nous avons comparé à celle utilisée lors de la première étude, dans le modèle du vieillissement physiologique. Au final en plus de permettre la discrimination entre sujets âgés et jeunes, les résultats obtenus avec cette nouvelle séquence se sont révélés être beaucoup moins sensibles au bruit. / One of the main goals of modern neuroimaging is the identification of new markers that can help in the diagnosis and monitoring of neurological pathologies. Multimodal magnetic resonance imaging (MRIm), is an approach allowing the evaluation of several complementary biomarkers within one MRI. This approach has already demonstrated its efficiency in several recent studies, and in particular in Parkinson's disease. We added a new biomarker to the MRIm approach previously used i.e. shape changes of subcortical structures based on T1 images. This marker is now a part of our MRIm approach along with: (i) volumetry from T1 images, (ii) microstructural integrity and orientation from diffusion images and (iii) metal deposits from T2* relaxometry. We applied this multimodal MRI approach to an other neurodegenerative disease, the Alzheimer's disease at a prodromal stage. Results of this preliminary study gave us the opportunity to suggest the existence of two different physiopathological processes at the prodromal phase of the Alzheimer's disease. In fact we observed atrophy with modification of the microstructural integrity for the hippocampus and the amygdala, while only atrophy has been observed for the thalamus and the putamen. Those results also confirmed the necessity of studying neurodegenerative diseases in a multimodal way. Among MRIm markers, the T2* relaxometry for the quantification of intracerebral iron is one of the methods which has been developed lately at the Inserm U825. Dysregulation of iron metabolism and its accumulation are involved in the physiopathology of several neurodegenerative diseases like Parkinson's disease. The experience gained through the different clinical validation of this method in recent years has led us to improve it. Our work was to improve T2* relaxometry by optimizing the acquisition of the images on one hand, and the processing of the images on the other hand. We compared several resolutions, acquisition antennas, number of acquisition by echo time, to determine which parameters gave the higher signal to noise ratio. For the part about the process of the images, we compared the method used as a reference, the least square method using a Levenberg-Marquard algorithm, to an other method, the singular value decomposition to obtain the best estimation of the relaxation rate R2*. Then we were able to develop an optimized T2* relaxometry sequence, which we compared to the one used in the first study, but in the physiological ageing model. Finally in addition to allowing discrimination between elderly and young people, the results obtained with this new sequence were found to be much less sensitive to noise.

Híbridos poliuretano-acrílicos foram sintetizados via polimerização em emulsão, utilizando uma dispersão de poliuretano base poliol poliéster como semente para a polimerização dos monômeros acrílicos, no caso, acrilato de butila e ácido metacrílico. As propriedades das dispersões híbridas resultantes foram avaliadas por espalhamento dinâmico de luz, teor de sólidos, pH e potencial Zeta. Os polímeros resultantes da secagem das dispersões aquosas foram caracterizados por cromatografia por exclusão de tamanho, calorimetria exploratória de varredura, análise dinâmico-mecânica, dureza, microscopia ótica do processo de cristalização, microscopia de força atômica, microscopia eletrônica de transmissão. A influência do método de síntese na morfologia dos híbridos foi avaliada. / PU-acrylic hybrids were prepared via emulsion polymerization, using an aqueous polyurethane dispersion as a seed for the acrylic monomers polymerization. Different quantities of acrylic monomers (butyl acrylate and methacrylic acid) were polymerized. The properties of the resulting hybrid dispersions were evaluated through dynamic light scattering, solid content, pH and Zeta potential. The resulting polymers obtained from dried dispersions were characterized via size exclusion chromatography, differential scanning calorimetry, dynamic mechanical analysis, optical microscopy of the crystallization process, atom force microscopy and transmission electron microscopy. The influence of the synthetic method on the morphology of the hybrids was evaluated.

Neste trabalho foram produzidas dispersões aquosas poliuretânicas com formulações variadas, obtidas pelo processo em duas etapas. Na primeira etapa foi obtido um prepolímero e na segunda etapa, através da reação de extensão de cadeia foi obtido o polímero final. Nas sínteses foram empregados o diisocianato de isoforona (IPDI) e como polióis o poli(glicol propilênico) (PPG) e três diferentes tipos de polibutadieno líquido hidroxilado (HTPB) comerciais. A fim de possibilitar a dispersão dos poliuretanos em água, foi introduzido em sua estrutura o ácido dimetilolpropiônico (DMPA), que após neutralização com trietilamina (TEA) forneceu os sítios iônicos responsáveis pela estabilidade das dispersões em água. Como extensor de cadeia foi utilizado a hidrazina (HYD). As dispersões aquosas poliuretânicas obtidas foram avaliadas quanto ao teor de sólidos totais, tamanho médio de partícula e viscosidade. Os filmes formados a partir dessas dispersões foram avaliados quanto à sua aparência visual, propriedades mecânicas, estabilidade térmica por análise termogravimétrica (TGA) e espectroscopia na região do infravermelho (FTIR). Todas as dispersões obtidas apresentaram teor de sólidos totais entre 31 a 45% e tamanho de partícula na faixa de 70 a 221 nm. / In this work polyurethane aqueous dispersions with varied compositions, synthesized by a two steps process were produced. On the first step it was obtained a prepolymer and on the second one, by the reaction of chain extension with hydrazine (HYD) was obtained the final polymer. In the prepolymer synthesis, diisocyanate of isophorone (IPDI), poly(propylene glycol) (PPG), three different types of hydroxy-terminated polybutadienes (HTPB) and, in order to make possible the polyurethane dispersion in water, dimethylol propionic acid (DMPA), were employed. Afterwards the acid groups were neutralized with triethylamine (TEA) to provide the ionic groups responsible for the dispersion stability in water. The polyurethane aqueous dispersions produced in this work were evaluated through the solids content, particle size and viscosity. The films formed from these dispersions were characterized by their visual appearance, mechanical properties, thermal stability (TGA) and by infrared spectroscopy (FTIR). All the obtained dispersions presented solids content between 31 to 45 percent (m/m) and particle size between 70 to 221 nm.

L'utilisation d'un électrolyte aqueux pour la technologie Li-ion devrait permettre des performances en termes de puissance et de coût tout en garantissant une sécurité de fonctionnement et un impact neutre vis-à-vis de l'environnement. Cette technologie utilise des composés d'insertion du lithium fonctionnant habituellement en milieu organique dont le choix doit être adapté à un électrolyte aqueux, présentant une fenêtre de stabilité électrochimique réduite. Le travail de thèse porte dans un premier temps sur la sélection des différents éléments constituant un accumulateur Li-ion aqueux: choix de l'électrolyte, des collecteurs de courant, des liants d'électrode et des matériaux d'électrode. Les performances électrochimiques en milieu aqueux de différents composés d'insertion du lithium ont été évaluées. Afin d'augmenter la fenêtre de stabilité électrochimique de l'électrolyte aqueux, la passivation des électrodes par réduction de sels de diazonium a été réalisée. L'influence de la nature des sels de diazonium et de l'épaisseur des films sur les performances électrochimiques des électrodes a été évaluée par diverses techniques, voltampérométrie et impédance électrochimique. Les résultats obtenus montrent l'impact positif des dépôts obtenus vis-à-vis de l'augmentation de la surtension de réduction de l'eau. Ces travaux ouvrent la voie à des perspectives prometteuses sur cette technologie Li-Ion aqueuse. / The use of aqueous electrolytes should permit to improve power performances and decrease significantly the battery cost. Moreover, these kind of electrolytes guarantee a safely use with reduced consequence on the environment. This technology use active materials enable to inserted and deinserted lithium ion. But the choice of lithium insertion compounds was guided and limited by the water electrochemical stability. We selected each component of the Li-ion cell which could be used in aqueous electrolyte; the lithium salt, the binder and the active material. The electrochemical performances of several active materials in aqueous electrolyte were evaluated. In order to increase the Li-ion cell tension, a passive film was form on the electrode surface by diazonium salt reduction. Influence of molecule design and film thickness were studied by voltammetry and electrochemical impedance spectroscopy. The results clearly show the interest of the formation of these films for lowering the reduction potential of water on glassy carbon and practical Li-ion electrode. This study opens very promising route for the aqueous lithium batteries.