Les matières en suspension (MES) sont constituées de colloïdes et particules et sont couramment décrites comme des agrégats hétérogènes formées de phases minérales, organiques et biologiques et possédant une forte réactivité de surface. Cette étude vise à étudier l’évolution de composition spatiale et temporelle des MES de la rivière Moselle (Lorraine, France) et également d’étudier la réactivité des MES vis-à-vis de contaminants métalliques. Les MES ont été collectées à différentes stations le long de la rivière Moselle et selon différents régimes hydriques. Des études microscopiques et macroscopiques ont été réalisées dans le but de caractériser les MES. Les résultats ont montré que la composition minérale des MES était relativement constante (1) le long de la Moselle (2) durant différents régimes hydriques et que la géologie du bassin versant contribuait grandement à la composition des MES. Les affluents de la Fensch et de l’Orne, deux rivières impactées par l’héritage industriel ont cependant montré la présence de particules d’origine anthropique. Cette étude a également montré le rôle majeur des MES dans le transport des TMEs et REEs quel que soit le débit. La caractérisation organique des MES a également montré des variations atténuées révélant l’aspect intégrateur d’un bassin versant de cette taille. Des variations saisonnières ont tout de même été observées avec une production autochtone plus élevée durant l’été. L’augmentation du débit a engendré une diminution de la teneur en matière organique ainsi que la présence d’une matière organique plus dégradée. Hormis les stations sur la Fensch et l’Orne, les propriétés de surface des MES sont homogènes, en relation avec la composition des particules. Les études ont également montré que le zinc s’associait de manière différente selon la quantité de zinc en solution. Enfin, l’étude comparée du mode d’association du zinc sur les composés modèles et les MES naturelles a montré la contribution des phyllosilicates dans le transport du zinc / Suspended Particulate Matter (SPM) in rivers, are constituted of colloidal and particulate matter, and described as heterogeneous aggregates of mineral, organic and biological phases which display high and reactive surface area. This study aimed to investigate the spatial and temporal composition evolution (Mineral and organic) of SPM along the Moselle River (Lorraine, France). SPM were collected at different stations along the river and at different regime flow. Macroscopic and microscopic studies were performed in order to characterize natural SPM. The second objective was to investigate the reactivity of SPM toward metallic contaminants. The results showed that the grain size distribution, elemental composition and mineralogy of SPM along the Moselle River and during different regime flow showed only slight variations, except for the Fensch and Orne tributaries, two rivers that were impacted by inherited steel making industrialization and different land use. The results also revealed that the catchment geology greatly contributed to the SPM composition in the river and highlighted the fact that SPM play a high contribution in TMEs and REEs transportation. The SPM organic matter characterization also showed slight variations through the catchment revealing the diffuse pollution in a catchment of this size. Seasonal variations were observed with strong autochthonous production during low flow level in summer. Regime flow increase resulted in the decrease of TOC content and in the presence of more degraded OM. Except for Fensch and Orne stations, surface properties of SPM are similar in relation with SPM composition. This study also showed that Zn association mode differed with different Zn concentrations. The comparison between Zn association mode on lab controlled particles and natural SPM revealed the contribution of phyllosilicates in zinc transport

Baseando-se na possibilidade de inserção de um novo material de origem têxtil natural animal, bem como, a reciclagem de aproximadamente 1,175 milhões de toneladas descartadas anualmente da matéria-prima estudada (UBABEF, 2011), esta pesquisa teve como objetivo geral efetuar a caracterização física e microscópica de fibra de pena de frango para finalidade têxtil seja para o desenvolvimento de fios têxteis, não tecidos e reforço em compósitos ou outras aplicações. Deste modo, foram objetivos: i) realizar levantamento bibliográfico sobre estrutura e composição de penas e fibras de penas, reciclagem, aplicações existentes, técnicas e processos de caracterização da fibra; ii) coleta do material fibroso proveniente de um matadouro doméstico de frangos; iii) preparação do material, lavagem e secagem das penas; iv) testes mecânicos de caracterização como: alongamento, elasticidade e resistência realizados por meio do dinamômetro Instrom, determinação do teor de regain, umidade e densidade da fibra, bem como a taxa de encolhimento da fibra; v) testes microscópicos de caracterização como: microscopias longitudinais e transversais; vi) propostas e direcionamento do emprego das fibras caracterizadas para finalidade de produção têxtil. As principais conclusões foram: i) bibliografia inédita em português sobre penas de frango para a área têxtil; ii) estudo inédito no Brasil e na língua portuguesa de propriedades físicas e microscópicas de fibras de pena de frango; iii) com base em suas propriedades estruturais, perceberam-se características como brilho, conforto, maciez, toque, permeabilidade à líquido, leveza, entre outras propriedades, aumentando assim seu potencial de empregabilidade têxtil; iv) potencial de fiação e fabricação de têxteis para diversas aplicações. Publicações e palestras foram realizadas com os resultados desta dissertação. / Based on the possibility of developing a new textile material of natural animal origin, as well as the recycling of the studied raw material, of which approximately 1.175 million tons are annually discarded as waste in Brazil (UBABEF, 2011), this study aimed to characterize the general physical and microscopical fibers of chicken feathers for textile purpose for the development of textile yarn, non-woven and composite reinforcement. Its objectives were: i) to analyze the academic literature about the structure and composition of feathers and feather fibers, as well as its recycling, existing applications, processes and techniques of fiber characterization, ii) the collection of fibrous material from a chicken slaughterhouse, iii) the preparation of material, washing and drying the feathers, iv) to develop mechanical characterization tests such as elongation, elasticity and resistance made by Instrom dynamometer, determining the content, moisture regain and fiber density, v) to perform the microscopic characterization tests such as microscopy longitudinal and transverse, and vi ) to draft proposals on the employment of the analyzed and characterized fibers for purposes of producing textiles (yarns, reinforcement for composites, nonwoven blankets, etc.). The main findings were: i) unpublished literature in Portuguese about chicken feathers for the textile area, ii) unpublished study in Brazil and in portuguese language of physical and microscopic properties of chicken feathers\' fibers for the development of textile products of natural origin from such chicken feathers, iii) the identification of the potential for the production of blended yarn with cotton / wool, blankets and non-woven and reinforcement for composites, based on their physical, mechanical and microscopic properties, and, iv) the identification of the potential for yarn production (via spinning) and textile manufacturing for various applications. Publications and lectures were held with the results of this dissertation.

Analisou-se 54 amostras de vírus da raiva isoladas de diferentes espécies animais e de seres humanos do Estado do Maranhão, inicialmente pelas técnicas tradicionais de imunofluorescência direta (IFD) e de inoculação intracerebral em camundongos (ICC), com o objetivo de realizar um estudo de epidemiologia da doença. No reteste, todas as amostras foram positivas na IFD e 19 resultaram negativas à ICC. O comportamento biológico dos isolados foi estudado em camundongos, revelando um período de incubação entre 7 e 17 dias, com sinais clínicos variados e duração média de 4 dias. Para a avaliação da patogenicidade, foram selecionadas cinco amostras do estudo, oriundas de diferentes espécies, como vírus de desafio nos camundongos imunizados com uma vacina comercial de vírus inativado. Os resultados do desafio indicaram que a proteção conferida pela vacina foi baixa para todas as amostras. A presença de anticorpos no soro dos camundongos vacinados foi demonstrada em diferentes períodos de vacinação. A tipificação antigênica de quatro amostras de vírus foi realizada pela imunofluorescência indireta (IFI) utilizando um painel de anticorpos monoclonais (MAbs) procedentes do Canadian Food and Inspection Agency, Ottawa, Canadá, identificando o perfil correspondente à variante de morcego hematófago Desmodus rotundus. Na caracterização genética com base nos genes que codificam a glicoproteína G e nucleoproteína N, observou-se que os isolados foram divididos em dois grupos genéticos independentes associados a ciclos endêmicos distintos. Esses resultados permitem concluir que no Estado do Maranhão circulam pelo menos duas variantes do vírus da raiva, mantidas por carnívoros terrestres e morcegos hematófagos. Destaca-se que houve variação regional entre as amostras isoladas em diferentes áreas geográficas. Além disso, foram constatados hospedeiros inesperados nos clados formados. Também, não houve variação temporal nas amostras pesquisadas. / Fifty four rabies virus samples isolated from different animal species and humans, diagnosed positive by means of the direct fluorescent antibody test (dFA) and mouse inoculation test (MIT) in the State of Maranhão were selected for an epidemiologic study. In the retest, all these samples were dFA-positive, but 19 were negative by the MIT. The biologic behavior of these samples was assessed in mice by intracerebral inoculation and the incubation period was between 7 and 17 days, showing varied clinical signs with an average duration of 4 days. For the evaluation of the pathogenicity, five rabies viruses isolated from different species were selected, and used as the challenge viruses to be inoculated into mice been vaccinated previously with an inactivated commercial rabies vaccine. The results of the challenge experiments indicated low protection of the vaccine against the challenge viruses. The presence of rabies antibody was demonstrated in the sera of vaccinated mice taken at different intervals after vaccination. The antigenic typing was performed in four samples by using the indirect fluorescent antibody test (IFI) with a panel of monoclonal antibodies (MAbs) provided by the Canadian Food and Inspection Agency, Ottawa, Canada, and the profile identified was closely related to that of the Desmodus rotundus vampire bat. The genetic characterization based on genes coding the glycoprotein G and nucleoprotein N genes indicated that isolates were divided into two independent genetic groups associated to distinct endemic cycles. With the results obtained, we conclude that in the State of Maranhão there are circulating at least two distinct variants of rabies viruses, maintained by terrestrial carnivores and vampire bats. Regional variation among the isolates taken from different geographic areas has been found. And the rabies virus isolates grouped into clades were associated with unusual host species and no temporal variation was observed among the isolates.

Les nanoparticules de dioxyde de titane (TiO2) sont largement utilisées dans les cosmétiques, notamment dans les lotions solaires, pour leurs propriétés optiques intéressantes. Cependant, le TiO2 étant très réactif et potentiellement nocif pour les cellules cutanées, celui-ci est recouvert d’une couche de passivation composée d’espèces chimiques inertes. D’autres traitements de surface peuvent par la suite être appliqués afin de faciliter leur dispersion dans les cosmétiques. Ainsi, les nanoparticules de TiO2 de grades cosmétiques ont des chimies de surface variées qui leur confèrent des propriétés physicochimiques propres. Cependant, le comportement de ces particules lors de leur utilisation en émulsion cosmétique est peu connu. Lors de ce travail de thèse, plusieurs systèmes nanoparticules/émulsion ont été étudiés au cours de leur vieillissement accéléré et suivant les conditions d’utilisation. Tout d’abord, l’impact de deux nanoparticules de traitements de surface différents a été testé sur les mécanismes de (dé)stabilisation des émulsions solaires. Puis, les nanoparticules en émulsion ont été caractérisées au cours du temps et ont fait apparaitre des modifications chimiques rapides au niveau de leur surface. Celles-ci affectent les propriétés physicochimiques des surfaces et ont été prises en compte lors du suivi de l’impact de ces nanoparticules sur les bactéries à travers des protocoles imitant les conditions réelles d’exposition. / Nanoparticles of titanium dioxide (TiO2) are currently used in cosmetics, especially in sunscreens, because of their interesting optical properties. However, the TiO2 is really reactive and could promote the formation of dangerous species for the cutaneous cells. For that reason, these particles are passivated by the application of inert surface treatments. Other coatings could be added in order to improve the dispersion of nanoparticles in the emulsion. Hence, the cosmetic grades of TiO2-nanoparticles have diverse physicochemical surface properties and their behavior in cosmetic use is uncertain. In this work, nanoparticles/emulsion systems were studied during their accelerated aging, mimicking use conditions. First, the impact of two nanoparticles with different surface treatments were tested on the (de)stabilization mechanisms in emulsions. Then, the nanoparticles were characterized within the emulsions and highlighted quick surface modifications. As these changed the physicochemical surface properties of the nanoparticles, they were taken into account during the evaluation of the NP impact on cutaneous bacteria.

Among fungal pathogens responsible for opportunistic infections, species of the genus Candida have a major role (Mitchell, 1998). Various Candida species cause superficial infections which can be cured by the currently available antifungal arsenal (Noble and Johnson, 2007). However, species of the genus Candida are also responsible for life-threatening systemic infections, particularly in immunocompromised patients with weakened immune system. Among Candida species, C. albicans, which can also be a commensal of the skin and the gastrointestinal and genitourinary tracts, is responsible for the majority of Candida bloodstream infections. However, there is an increasing incidence of infections caused by C. glabrata because it is less susceptible to azoles. Other medically important Candida species include C. parapsilosis, C. tropicalis and C. dubliniensis. The problem has been further worsened by the emergence of many drug resistant isolates which pose a major hurdle during a given treatment regimen. Therefore, there is a dire need to identify novel drug targets and the current study focuses on one such protein found in C. albicans and related Candida species. CaGAL102 does not encode a functional galactose epimerase CaGAL102 was previously identified in the lab as a paralog of CaGAL10. CaGAL10 endoes a functional UDP-galactose 4-epimerase and it can complement a Scgal10 null strain. Further, work on the Gal10 protein in the encapsulated yeast Cryptococcus neoformans identified two Gal10 paralogs in the genome, Uge1 and Uge2 with distinct functions (Moyrand et al., 2008). A similar scenario is found in S. pombe in which two Gal10 sequence homologs have been annotated. In the light of these observations, we wanted to test if CaGAL102 also encodes a functional ScGAL10 homolog. We found that CaGAL102 could not complement Scgal10 null strain though there was a strong conservation in the cofactor and the catalytic motif in both the proteins. We found after a careful literature review that Gal10 belongs to a family of proteins called the short chain dehydratase/reductase family (SDR) (Jornvall et al., 1995), members of which are characterised by the presence of glycine rich cofactor binding motif at the N-terminus and an YXXXK catalytic motif. Proteins belonging to the SDR family have a residue level identity of 15-30% indicating early duplication and divergence. Based on our literature survey we carried out a BLAST search in the NCBI protein database using CaGal102 as the bait protein. We found that CaGal102 is 32% identical at the protein level to dTDP-glucose 4,6 dehydratase (RmlB), another member of the SDR family. RmlB is the second enzyme of the rhamnose biosynthetic pathway which gives rise to dTDP-rhamnose. This pathway is involved in cell wall biosynthesis in bacteria and it has been shown that rmlB is essential for growth of Mycobacterium smegmatis (Li et al, 2006). Interestingly rhamnose is not present in the cell wall of C. albicans. Biochemical characterisation of CaCaGal102 A plant homolog of RmlB is found in A. thaliana which uses UDP-glucose as the substrate (Oka et al., 2007). Based on our alignment data we identified many critical residues in CaGal102. Most importantly we identified that lysine at position 159 lies in the YXXXK motif and could be important for activity. We therefore, mutated the lysine at position 159 to alanine. In order to find out the biochemical function of CaGal102 in vitro, we cloned expressed and purified recombinant wild type and catalytic mutant proteins from E. coli and used the purified proteins for our assays. We found that CaGal102 uses UDP-glucose as the preferred substrate. To further substantiate our data, we reintegrated the wild type or the mutant alleles in the native locus of CaGAL102 and checked for the rescue of morphology defects like filamentation and sensitivity to cell wall damaging agents. We also found that the Cagal102∆/∆ strain is avirulent in a mouse model of systemic infection. We have also carried out infection studies with the null mutant and the wild type and the catalytic mutant reintegrant strains. Our observation suggests that reintegrating one copy of the wild type allele rescues the virulence defect. Interestingly the strain harbouring one copy of the mutant allele behaves like the null mutant in a mouse model of systemic infection. We have also identified sequence homologs of CaGal102 in related Candida species. It is plausible to think that the homologs in related species also have similar effects and hence targeting this protein by a small molecule could help in treating candidiasis caused by related species. CaGAL102 is involved in cell wall architecture in C. albicans To elucidate the role of CaGal102 in C. albicans we generated a knockout out strain and studied various mutant phenotypes. The most striking observation was that the cells of the null mutant were filamentous as compared to the wild type control when grown in normal rich media. Further the cells were sensitive to various cell wall damaging agents and also to hygromycin B. We reasoned that lack of CaGal102 causes perturbation in the cell wall architecture rendering the cells sensitive to various cell wall damaging agents. To further strengthen this hypothesis, we decided to study the genetic interaction of CaGAL102 with genes known to be involved in cell wall biosynthesis in C. albicans. One of the candidate genes we chose for our study was GAL10, deletion of which in C. albicans renders the cells sensitive to various cell wall damaging agents. Loss of function of UGE1 in C. neoformans impaired biosynthesis of a cell wall component, galactoxylomannan. We found that cells lacking both Gal102 and Gal10 adhered to nylon membranes poorly as compared to single mutants or the wild type control. The second gene we chose was a P-type ATPase, PMR1 deletion of which causes increased sensitivity to cell wall damaging agents and hyper-activation of the cell wall integrity pathway similar to Cagal102∆/∆ strain. We found that cells lacking both Pmr1 and Gal102 were more sensitive to hygromycin B as compared to the single mutants. This confirmed our idea that CaGal102 is a novel gene involved in cell wall biogenesis in C. albicans. REFERENCES: Mitchell, A.P. (1998) Dimorphism and virulence in Candida albicans. Curr Opin Microbiol, 1, 687-692. Noble, S.M. and Johnson, A.D. (2007) Genetics of Candida albicans, a diploid human fungal pathogen. Annu Rev Genet, 41, 193-211. Moyrand, F., Lafontaine, I., Fontaine, T. and Janbon, G. (2008) UGE1 and UGE2 regulate the UDP-glucose/UDP-galactose equilibrium in Cryptococcus neoformans. Eukaryot Cell, 7: 2069-2077. Jornvall Hans, Persson Bengt, Krook Maria,‟ Atrian Silvia, Gonzalez-Duarte Roser, Jeffery Jonathan, and Ghosh Debashis (1995). Short-Chain Dehydrogenases Reductases (SDR). Biochemistry, 34: 6004-13. Li, W., Xin, Y., McNeil, M.R. and Ma, Y. (2006) rmlB and rmlC genes are essential for growth of mycobacteria. Biochem Biophys Res Commun, 342: 170-178. Oka, T., Nemoto, T. and Jigami, Y. (2007) Functional analysis of Arabidopsis thaliana RHM2/MUM4, a multidomain protein involved in UDP-D-glucose to UDP-L-rhamnose conversion. J Biol Chem, 282: 5389-5403.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / Barium Titanate (BaTiO3 BT) based Ceramic materials have a wide industrial application as Multilayer Ceramic Capacitors (MLCCs) mainly due to its high dielectric constant and good capacitance stability with the temperature change, however this material also presents some limitations, for example, oxidation of low cost electrodes. Several ways of BT modifications have been proposed in Literature, as example, the use of different synthesis methods and the doping with different ions. Therefore, the present work had as objectives the synthesis, sintering and electrical characterization of the BaTiO3 and Ba0.77Ca0.23TiO3 (Barium Calcium Titanate) ceramics. The Sol Gel Proteic method was used to powder synthesis, in this method, coconut water is employed as polymeric agent instead of the conventional alcoxide precursors. The characterization was done using the differential thermal analysis, thermogravimetry, x-ray powder diffraction, scanning electron microscopy and impedance spectroscopy techniques. Both, the calcined powders at 1100 °C and the sintered ceramics at 1350 °C presented single crystalline phase, with good microstructural homogeneity and relative density higher than 90%. The sintered ceramics presented a dielectric constant value at room temperature of 1200 (BT) and 680 (BCT), and dielectric loss of 4,8% (BT) and 1,8% (BCT). Besides, the BCT ceramics presented a Curie temperature on average 14 °C above that observed in Literature. Finally, the activation energies of the conductive process of the grain an grain boundary regions were evaluated following two distinct methods using: i) the Brick-layer model; and ii) the average relaxation frequency of each ceramic region, grain and grain boundary. The obtained values by the two methods are in accordance with them and suggest that the dominant conduction mechanism occurs by oxygen vacancy diffusion created still during the sintering process. / Materiais cerâmicos a base de titanato de bário (BaTiO3 BT Barium Titanate ) possuem uma larga aplicação industrial como Capacitores Cerâmicos Multicamadas (MLCCs Multi layers ceramic capacitors ) devido, principalmente, a sua alta constante dielétrica e boa estabilidade da capacitância com a variação da temperatura, porém esse material apresenta também algumas limitações, como por exemplo, a oxidação de eletrodos de baixo custo. Diversas modificações no BT têm sido sugeridas na literatura, como a utilização de diferentes métodos de síntese e a dopagem com diferentes íons. Dessa forma, o presente trabalho objetivou a síntese, a sinterização e a caracterização elétrica de cerâmicas de BaTiO3 e Ba0.77Ca0.23TiO3 (Titanato de Bário e Cálcio BCT Barium Calcium Titanate ). Para a síntese dos pós foi utilizado o método sol-gel proteico, neste método, a água de coco é utilizada como agente polimérico, ao invés dos alcóxidos convencionais. Para a caracterização das amostras foram utilizadas as técnicas de análise térmica diferencial, termogravimetria, difração de raios X, microscopia eletrônica de varredura e espectroscopia de impedância. Os pós calcinados a 1100°C bem como as cerâmicas sinterizadas a 1350°C e apresentaram fase cristalina única, com boa homogeneidade microestrutural e densidade relativa superior a 90%. O valor da constante dielétrica à temperatura ambiente foi de 1200 para o BT e 680 para o BCT com perda dielétrica de 4,8% e 1,8%, respectivamente. Além disso, as cerâmicas de BCT apresentaram uma temperatura de Curie em média 14 °C acima dos valores observados na Literatura. Por ultimo, as energias de ativação dos processos condutivos nas regiões de grão e de contorno de grão foram obtidas seguindo dois procedimentos distintos: i) utilizando o modelo de brick-layer; e ii) utilizando a frequência de relaxação média de cada região da cerâmica, grão e contorno de grão. Os valores obtidos pelos dois métodos concordaram entre si e sugerem que o mecanismo de condução dominante ocorre por vacâncias de O2- formadas ainda durante o processo de sinterização.

Analisou-se 54 amostras de vírus da raiva isoladas de diferentes espécies animais e de seres humanos do Estado do Maranhão, inicialmente pelas técnicas tradicionais de imunofluorescência direta (IFD) e de inoculação intracerebral em camundongos (ICC), com o objetivo de realizar um estudo de epidemiologia da doença. No reteste, todas as amostras foram positivas na IFD e 19 resultaram negativas à ICC. O comportamento biológico dos isolados foi estudado em camundongos, revelando um período de incubação entre 7 e 17 dias, com sinais clínicos variados e duração média de 4 dias. Para a avaliação da patogenicidade, foram selecionadas cinco amostras do estudo, oriundas de diferentes espécies, como vírus de desafio nos camundongos imunizados com uma vacina comercial de vírus inativado. Os resultados do desafio indicaram que a proteção conferida pela vacina foi baixa para todas as amostras. A presença de anticorpos no soro dos camundongos vacinados foi demonstrada em diferentes períodos de vacinação. A tipificação antigênica de quatro amostras de vírus foi realizada pela imunofluorescência indireta (IFI) utilizando um painel de anticorpos monoclonais (MAbs) procedentes do Canadian Food and Inspection Agency, Ottawa, Canadá, identificando o perfil correspondente à variante de morcego hematófago Desmodus rotundus. Na caracterização genética com base nos genes que codificam a glicoproteína G e nucleoproteína N, observou-se que os isolados foram divididos em dois grupos genéticos independentes associados a ciclos endêmicos distintos. Esses resultados permitem concluir que no Estado do Maranhão circulam pelo menos duas variantes do vírus da raiva, mantidas por carnívoros terrestres e morcegos hematófagos. Destaca-se que houve variação regional entre as amostras isoladas em diferentes áreas geográficas. Além disso, foram constatados hospedeiros inesperados nos clados formados. Também, não houve variação temporal nas amostras pesquisadas. / Fifty four rabies virus samples isolated from different animal species and humans, diagnosed positive by means of the direct fluorescent antibody test (dFA) and mouse inoculation test (MIT) in the State of Maranhão were selected for an epidemiologic study. In the retest, all these samples were dFA-positive, but 19 were negative by the MIT. The biologic behavior of these samples was assessed in mice by intracerebral inoculation and the incubation period was between 7 and 17 days, showing varied clinical signs with an average duration of 4 days. For the evaluation of the pathogenicity, five rabies viruses isolated from different species were selected, and used as the challenge viruses to be inoculated into mice been vaccinated previously with an inactivated commercial rabies vaccine. The results of the challenge experiments indicated low protection of the vaccine against the challenge viruses. The presence of rabies antibody was demonstrated in the sera of vaccinated mice taken at different intervals after vaccination. The antigenic typing was performed in four samples by using the indirect fluorescent antibody test (IFI) with a panel of monoclonal antibodies (MAbs) provided by the Canadian Food and Inspection Agency, Ottawa, Canada, and the profile identified was closely related to that of the Desmodus rotundus vampire bat. The genetic characterization based on genes coding the glycoprotein G and nucleoprotein N genes indicated that isolates were divided into two independent genetic groups associated to distinct endemic cycles. With the results obtained, we conclude that in the State of Maranhão there are circulating at least two distinct variants of rabies viruses, maintained by terrestrial carnivores and vampire bats. Regional variation among the isolates taken from different geographic areas has been found. And the rabies virus isolates grouped into clades were associated with unusual host species and no temporal variation was observed among the isolates.

Dans le cadre d’une Convention CIFRE, la thèse est financée par la société Renault, ce travail vise à développer un supercondensateur carbone-carbone dont le coût de fabrication est compatible avec le marché automobile ; c’est en effet leur coût élevé qui constitue encore à l’heure actuelle un frein à leur développement. Dans une première partie de ce travail, il a été montré que l’essentiel du coût repose en grande partie sur la purification de l’électrolyte utilisé mais surtout du carbone activé, qui est le matériau actif d’électrode. Notre travail s’est donc focalisé sur l’étude du vieillissement électrochimique de cellules de supercondensateurs de laboratoire assemblées avec différents carbones, afin d’essayer d’identifier les phénomènes responsables du vieillissement. Un autre objectif a été d’identifier les caractéristiques que doivent présenter les carbones alternatifs candidats au remplacement des carbones commerciaux. L’étude réalisée dans ce travail de thèse a permis de définir deux modes de vieillissement différents suivants les carbones utilisés. Un premier type de vieillissement entraîne l’augmentation conjointe de la résistance série équivalente et de la capacité, dû à une dégradation/oxydation du carbone à l’électrode positive. Un second mode de vieilissement mène à l’augmentation seule de la résistance série équivalente par la formation d’une couche d’interface solide conductrice ionique. Quelque soit le mode vieillissement, aucune corrélation directe n’a pu être établie avec les fonctions de surface des carbones activés. La piste la plus probable repose sur le taux et la nature des impuretés présentes dans le carbone activé, certaines étant électroactives, voire pouvant jouer un rôle catalytique. / In the context of a CIFRE Convention, the thesis is financed by Renault s.a.s., this work aims at developing a carbon-carbon supercapacitor whose manufacturing cost is compatible with the automotive market, which still hinders their development. In a first part of this work, it has been shown that the cost mainly depends on the purity of the materials used: electrolyte but also activated carbon, the electrode active material. Our work has therefore been focused on the study of the electrochemical aging of laboratory supercapacitor cells assembled with different carbons, to identify their ageing mechanisms and to define the key features alternative carbons must achieve to replace commercial carbons. This work has evidenced two different modes of aging, depending on the carbon used. A first ageing mode results in the joint increase of the equivalent series resistance as well as the capacity, due to a degradation / oxidation of the carbon at the positive electrode. A second mode leads to the sole increase in equivalent series resistance by the formation of an ionic conductive solid interface layer. Whatever the aging mode, no clear influence of the surface functions of activated carbons could be evidenced. The most likely assumption is based on the content and the nature of the impurities present in the activated carbon, some of which are electroactive and can even play a catalytic role.

<p>In recent decades, alternatives to traditional coal and fossil fuels were utilized to reduce carbon emissions. Among these alternatives, natural gas is a cleaner fuel and is abundant globally. Shale gas, a form of natural gas that also contains light alkanes (C2-C4), is presently being employed to produce olefins, which can be upgraded to higher molecular weight hydrocarbons. This thesis describes efforts to develop new catalytic materials and characterizations for the conversion of shale gas to fuels.</p> <p>In the first half, silica supported Pt-Cr alloys containing varying compositions of Pt and Pt₃Cr were used for propane dehydrogenation at 550°C. Although a change in selective performance was observed on catalysts with varying promoter compositions, the average nano-particle structures determined by <i>in situ</i>, synchrotron x-ray absorption spectroscopy (XAS) and x-ray diffraction (XRD) were identical. Further, this work presents a method for the characterization of the catalytic surface by these methods to understand its relationship with olefin selectivity. From this, we can gain an atomically precise control of new alloys compositions with tunable surface structures.</p> <p>Once formed by dehydrogenation, the intermediate olefins are converted to fuel-range hydrocarbons. In the second half, previously unknown single site, main group Zn²⁺ and Ga³⁺ catalysts are shown to be effective for oligomerization and the resulting products follow a Schutlz Flory distribution. Mechanistic studies suggest these catalysts form metal hydride and metal alkyl reaction intermediates and are active for olefin insertion and b-H elimination elementary steps, typical for the homogeneous, Cossee-Arlman oligomerization mechanism. Evidence of metal hydride and metal alkyl species were observed by XAS, Fourier transform infrared spectroscopy (FTIR), and H₂/D₂ isotope exchange. Understanding the reaction intermediates and elementary steps is critical for identifying novel oligomerization catalysts with tunable product selectivity for targeted applications. </p> <p> Through controlled synthesis and atomic level <i>in situ </i>characterizations, new catalysts compositions can be developed with high control over the resulting performance. An atomically precise control of the catalyst structure and understanding how it evolves under reaction conditions can help shed light on the fundamental principles required for rational catalyst design. </p>

<p>Extrusion Deposition Additive Manufacturing (EDAM) is a process in which fiber-filled thermoplastic polymers are mixed and melted in an extruder and deposited onto a build plate in a layer-by-layer basis. Anisotropy caused by flow-induced orientation of discontinuous fibers along with the non-isothermal cooling process gives rise to internal stresses in printed parts which results in part deformation. The deformation and residual stresses can be abated by modifying the fiber orientation in the extrudate to best suit the print geometry. To that end, the focus of this research is on understanding the effect of fiber orientation state and fiber properties on effective properties of the printed bead and the final deformation of a part. The properties of three different orientation tensors of glass fiber-filled polyamide and carbon fiber-filled polyamide were experimentally and virtually characterized via micromechanics. A thermo-mechanical simulation framework developed in ABAQUS© was used to understand the effects of the varying fiber orientation tensor and fiber properties on the final deformation of printed parts. In particular, a medium-size geometry that is prone to high deformation was simulated and compared among the three orientation tensors and two material systems. This serves to be a good preliminary study to understand microscopic properties induced deformations in EDAM.</p>