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On appelle biominéraux l’ensemble des minéraux fabriqués par le vivant. Ce sont des matériaux essentiels, présents dans la quasi-totalitédes espèces vivantes. Néanmoins les caractéristiques structurales, chimiques ainsi que les mécanismes de formation, et l’évolution de cesmatériaux sont encore fortement débattus. Cela s’explique notamment par les difficultés à étudier expérimentalement des espèces chimiquesévoluant en milieux biologiques.Bien que tout aussi complexe, une approche théorique, à l’échelle moléculaire, peut aider à la caractérisation de ces matériaux biologiqueset notamment la caractérisation de leurs interfaces formées avec les milieux biologiques environnants. Cela étant essentiel pour une meilleurecompréhension de la formation et de l’évolution de ces minéraux.Les oxalates de calcium constituent une famille de biominéraux très importante dans le monde du vivant. Ils constituent notamment les principales espèces cristallinesrencontrées dans les calculs rénaux où ils peuvent exister sous trois phases possédant différents degrés d'hydratation. Au cours de cette thèse, nous avons effectuéles simulations des propriétés spectroscopique IR et RMN des ces trois phases, ce qui permet d'obtenir une signature propre à chacune d'entre elle, aidant ainsi àl'identification de ces phases à partir des spectres obtenus expérimentalement.Les phosphates de calcium font aussi partie des biominéraux. Ils composent la majeure partie du minéral osseux des mammifères. Ce minéral se trouvesous la forme de nanoparticules décrites comme possédant un cœur cristallin d’hydroxyapatite substituées entourée d'une couche hydratée et désordonnée en surface.Durant ce travail de thèse, nous nous sommes intéressés à ces deux composantes. Concernant le cœur cristallin des particules, nous avons étudié en particulierle cas des substitutions par des carbonates car il s'agit de la substitution prédominante dans les apatites biologiques. En couplant ce travail à des expériencesde RMN solide nous pouvons proposé une localisation précise de ces substituants au sein de la maille d’hydroxyapatite.La couche désordonnée de surface est encore très mal comprise à l'heure actuelle et de nombreux modèles structuraux sont proposés dans la littérature pour la décrire. Nous avonsconsidéré un certain nombre d'entre eux pour lesquels nous avons modélisé les propriétés RMN, qui confrontées à celle issues de l'expérience nous ontpermis d'identifier les points forts et faibles des différentes hypothèses. / Biominerals are all the minerals produced by living organisms. They are essential materials, present in almost all living species. Nevertheless,the structural, chemical properties and, formation mechanisms and the evolution of these materials are still heavily debated. This is due in particular to thedifficulties of experimentally studying chemical species evolving in biologicalenvironments. Although, equally complex, a theoretical approach at the molecular level can help in the characterization of these biological materialsand in particular the characterization of their interfaces formed with the surrounding biological media. This is essential for a better understandingof the formation and evolution of these minerals.Calcium oxalates are essential biominerals that are very common in the living world. They constitute the main crystalline speciesencountered in kidney stones where they can exist in three phases possessing different degrees of hydration. In this, thesis we carried outsimulations to predict the IR and NMR spectroscopic properties of these three phases. Thsi enabled us to obtain specificsignature of each polyhydrate, and thus makes it possible to obtain a signature specific to each of them, thus helpingthe identification of these phases from the experimentally spectra obtained.Calcium phosphates are part of the bio/biological minerals. They make up the major part of the bone mineral of mammals. This mineral is in the form of nanoparticles havinga crystalline core of hydroxyapatite and a hydrated and disordered surface layer.During this thesis we were interested in these two components. Concerning the crystalline core of the particles, we studied in particularthe case of carbonate substitutions because of its predominant substitution in biological apatites. By combining this work with solid state NMR experimentswe can propose a precise localization of these substituents within the hydroxyapatite crystalline cell.The disordered surface layer is still very poorly understood and many structural models are proposed in the literature to describe it. We haveconsidered a number of them for which we have modeled the NMR properties which were then confronted with experimental results. The comparaisonmade it possible to identify the strengths and weaknesses of the various hypotheses.

The chemical reactivity of a solid is influenced to a marked degree by the presence of imperfections or defects in the solid. Bond strengths are considerably weaker at points of imperfection than elsewhere in the solid, and hence the initiation of reaction is favoured at these sites due to the relative ease of bond rupture. Line defects, such as edge or screw dislocations, jogs, Smekul cracks etc, are of prime importance in such changes. The surface of a solid or in intergranular boundaries, where a state of strain exists, are also favourable places for the initiation of a reaction, Point defects e.g. vacancies or interstitialions or atoms also play important roles in chemical change, often in conjuction with line defects.

CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / Oxaliplatina (OXL) à um composto de platina de terceira geraÃÃo com potente atividade citotÃxica contra vÃrios tipos de cÃncer, possuindo um efeito colateral de difÃcil tratamento, uma severa neuropatia perifÃrica. Estudos sugerem que o oxalato, metabÃlito da OXL, està envolvido no desenvolvimento dessa neuropatia sensitiva perifÃrica (NSP); de modo que foi publicada a sÃntese de um anÃlogo (LLC-1402) da OXL, livre de oxalato, tendo propriedades antitumorais (LIU et al., 2013). O objetivo do trabalho à estudar o papel do oxalato na neuropatia induzida por OXL em camundongos, comparando a OXL com LLC-1402. A NSP foi induzida por 2 injeÃÃes (iv.) por semana de OXL (2 mg/kg), em camundongos machos Swiss, durante 4  semanas, totalizando 9 injeÃÃes. LLC-1402 (7, 14 e 28 mg/kg) foi administrado (iv.) seguindo o mesmo esquema. Foram realizados testes nociceptivos (Von Frey eletrÃnico e TIC), semanalmente. Depois, foi escolhida a dose de 14 mg/kg do LLC-1402 para fazer um outro experimento, no qual foi acrescentada a injeÃÃo ip. de oxalato (1,7 mg/kg). No 28 dia, foi feita coleta de sangue para contagem total de leucÃcitos e dosagens bioquÃmicas. Nos 28 e 56 dias, foi feita a coleta de medula espinhal e GRD para imunofluorescÃncia para ATF-3, c-FOS, iNOS e NeuN. Os resultados mostraram que a OXL e o LLC-1402 foram capazes de diminuir o limiar de retirada da pata e o tempo de retirada da cauda significativamente (p<0,05), comparado ao grupo controle. A injeÃÃo de LLC-1402 junto com oxalato e somente oxalato tambÃm foi capaz de reduzir o limiar de retirada da pata e o tempo de retirada da cauda. Os grupos tratados com OXL, LLC-1402 e oxalato mostraram uma reduÃÃo significativa da contagem total de leucÃcitos. Para as dosagens bioquÃmicas (TGO, TGP, ureia, creatinina), nÃo houve diferenÃa estatÃstica entre os grupos. Houve um aumento da imunoexpressÃo de c-Fos no GRD nos grupos tratados com OXL, LLC-1402 e LLC-1402 junto com oxalato nos 28 e 56 dias, e somente oxalato no 28 dia. Foi observado esse aumento no corno dorsal da medula espinhal no 28 dia em todos os grupos tratados. Foi observado um aumento da imunoexpressÃo de ATF-3, no GRD e corno dorsal da medula espinhal, em todos os grupos tratados, nos 28 e 56 dias. NÃo houve diferenÃa significativa entre os grupos no GRD nem medula espinhal na imunoexpressÃo de iNOS no 56 dia; jÃ, no 28 dia, houve um aumento da imunoexpressÃo de iNOS no GRD. Os resultados mostraram que o oxalato pode estar envolvido parcialmente na NSP induzida por OXL. / Oxaliplatin (OXL) is a third generation platinum compound with potent cytotoxic activity against several types of cancers, having a side effect is difficult to treat, a severe peripheral neuropathy. Studies suggest that oxalate, OXL metabolite, is involved in the development of peripheral sensory neuropathy (PSN); so that was published the synthesis of an OXL analogue (LLC-1402), oxalate free, which has antitumor properties (LIU et al., 2013). The objective of this research is to study the role of oxalate in OXL induced neuropathy in mice, comparing OXL with LLC-1402. The PSN was induced by two injections (iv.) OXL (2 mg/ kg) per week, in male Swiss mice, for 4  weeks, totaling 9 injections. LLC-1402 (7, 14 and 28 mg / kg) was administered (iv.) following the same scheme. Nociceptive tests were performed (electronic von Frey and tail immersion test) weekly. After, it was chosen dose of 14 mg / kg of the LLC-1402 to perform another experiment, in which was added oxalate injection (1.7 mg/kg). In the 28th day, it was made blood collection for total leukocyte count and biochemical measurement. In the 28th and 56th days, spinal cord and DRG were removed for immunofluorescence for ATF-3, c-FOS, iNOS and NeuN. The results showed that both OXL and LLC-1402 were able to decrease the paw withdrawal threshold and tail withdrawal time significantly (p<0.05) compared to the control group. The injection of LLC-1402 together with oxalate and only oxalate was also able to reduce the paw withdrawal threshold and the tail withdrawal time. Moreover, all groups treated with OXL, LLC-1402 and oxalate showed a significant reduction in the total leukocyte count. The biochemical measurement (glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, urea, creatinine) showed no statistical difference between the groups. The results also showed increased c-Fos immunoexpression in GRD in groups treated with OXL, LLC-1402 and LLC-1402 together with oxalate in the 28 and 56 days, and only oxalate the 28th day. This increase was observed in the dorsal horn of the spinal cord at 28th day in all the treated groups. It was not observed this increase in the dorsal horn of the spinal cord in the 56th day. It was observed an increase in immunoexpression of ATF3 in DRG and spinal cord of dorsal horn in all treated groups in the 28th and 56th days. iNOS immunofluorescence showed no significant difference between groups in the DRG nor spinal cord, already in the 28th day, there was an increase in immunoexpression of iNOS in GRD. Thus, the results showed that the oxalate may be partially involved in PSN induced OXL.

This study evaluated the nutritional and antioxidant properties of Sesamum indicum, Cucumeropsis edulis and Cucurbita pepo seeds by determining proximate composition and mineral composition by atomic absorption spectroscopy and antioxidant assays. C. pepo had the highest protein (28.31%), S. indicum had the highest fat (52.53%) and C. edulis had the highest fiber content (6.23%), and highest total antioxidant capacity (199.75 mg AAE g−1 dry weight of ethanol extract). Magnesium, potassium, iron, calcium, sodium and zinc were the most abundant mineral elements present in these seeds.

Durant ce travail de thèse, d’importants paramètres concernant la synthèse de matériaux catalytiques nanostructurés à base de manganèse et d’oxydes de cobalt ont été établis. La corrélation entre les propriétés structurales du catalyseur et l’activité catalytique, ainsi que le mécanisme d’oxydation du CO ont été analysé au moyen d’une grande variété de méthodes expérimentales physico-chimiques.<p>De l’oxyde de manganèse non-stœchiométrique (MnOx) a été préparé par décomposition spinodale d’oxalate de manganèse trihydraté en ayant recours à la technique d’oxydation programmée en température (TPO). Tant l’analyse quantitative relatives à ces données TPO que les résultats obtenus par spectroscopie de structure au front d’absorption des rayons X (XANES), ainsi que par spectroscopie des photoélectrons X (XPS) ont permis d’estimer la stœchiométrie de l’oxyde avec un x situé entre 1.61 et 1.67. En accord avec à la fois la surface spécifique élevée et la combinaison d’isothermes d’adsorption/désorption de type I et IV, la microscopie électronique à transmission à haute résolution (HRTEM) démontre la présence de micro-bâtonnets caractéristiques et « imbriqués » les uns dans les autres, accompagné de particules nanocristalline à l’extrémité de ces bâtonnets.<p>Les découvertes faites par spectroscopie infra-rouge de réflexion diffuse par transformée de Fourier (DRIFTS), par études isotopiques et cinétiques suggère que l’adsorption des deux molécules, CO et O2, est suivie par leur réaction en surface via des intermédiaires de type carbonate/formate, pour finalement produire du CO2. Nous supposons un mécanisme de type Mars-van Krevelen où l’oxygène appartenant à la structure de type MnOx prend part dans l’oxydation catalytique du CO à basse température. Cependant, ces espèces mobiles d’oxygènes ne faisaient pas partie du cœur de phase du réseau d’oxyde, et de ce fait, ont été capables de « sauter » sur la surface et approvisionner les espèces oxygénées nécessaires à l’oxydation du CO déjà adsorbé.<p>Une structure spinelle d’oxyde de cobalt Co3O4 dans lequel le cobalt présente deux états de valence (+2 et +3) a été choisie pour élucider l’effet de la taille des particules sur l’activité lors de la réaction d’oxydation du CO. Tout d’abord, des nanoparticules monodispersées de cobalt métallique présentant une déviation standard en taille inférieure à 8% ont été synthétisées à partir de carbonyle de cobalt (Co2(CO)8) par une méthode optimisée «d’injection chaude». Un contrôle de la taille des nanoparticules dans la gamme 3 à 11 nm a pu être obtenu en variant la température d’injection du carbonyle de cobalt dans une solution de dichlorobenzène et d’acide oléique. La microscopie électronique à transmission (TEM) nous montre que ces particules de cobalt sont quasiment hémisphériques. Ensuite, de la silice poreuse (de type MCF-17) a été imprégnée par des nanoparticules de cobalt, et ensuite activée par TPO menant à des nanoparticules d’oxyde de cobalt. Des études par diffraction des rayons X (XRD) et spectroscopie des photoélectrons X (XPS) ont démontré la structure spinelle Co3O4. Finalement, l’activité des catalyseurs obtenus vis-à-vis de l’oxydation du monoxyde de carbone fut mesurée à 423 K et ce en fonction de la taille des particules. Les particules de Co3O4 présentant une taille allant de 5 à 8 nm se sont révélées les plus actives. Ceci peut s’expliquer par une plus grande mobilité des atomes d’oxygène en surface des nanoparticules d’oxyde de cobalt.<p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / A hiperestesia dentinÃria à um fenÃmeno sensorial complexo e de difÃcil soluÃÃo na clÃnica odontolÃgica. Apesar da grande diversidade de tratamentos propostos, ainda nÃo existe uma terapia considerada ideal para eliminar essa situaÃÃo desconfortÃvel. Esta dissertaÃÃo, constituÃda por dois artigos cientÃficos, teve por objetivos: (1) revisar criticamente a literatura disponÃvel sobre os principais aspectos relacionados à etiologia e ao tratamento da hiperestesia dentinÃria; (2) avaliar clinicamente a eficiÃncia de agentes anti-hiperestÃsicos no tratamento da hiperestesia dentinÃria. No estudo 1, a literatura cientÃfica pertinente ao assunto foi analisada atravÃs dos resultados de investigaÃÃes clÃnicas e laboratoriais pesquisadas usando a base de dados medline e busca manual de referÃncias citadas em artigos cientÃficos. No estudo 2, um total de 164 dentes, provenientes de 30 pacientes com diagnÃstico de hiperestesia dentinÃria moderada ou severa, foi dividido aleatoriamente em trÃs grupos e avaliado clinicamente de acordo com o tratamento administrado: aplicaÃÃo de laser de arseniato de gÃlio-alumÃnio (AsGaAl), aplicaÃÃo de gel de oxalato de potÃssio a 3% e aplicaÃÃo de gel placebo. As aplicaÃÃes dos tratamentos foram realizadas em intervalos semanais, durante o perÃodo de quatro semanas consecutivas e o grau de sensibilidade foi mensurado para cada dente atravÃs de uma escala visual analÃgica em resposta aos estÃmulos tÃtil (sonda exploradora) e evaporativo (jato de ar) antes da primeira aplicaÃÃo (baseline), imediatamente apÃs e trÃs meses apÃs a Ãltima aplicaÃÃo dos tratamentos. Os dados foram submetidos à anÃlise estatÃstica pelo teste de Kruskal-Wallis (p=0,05) e o grau de reduÃÃo da hiperestesia dentinÃria foi avaliado para cada um dos perÃodos observacionais em relaÃÃo ao baseline. A anÃlise crÃtica apresentada no artigo 1 mostrou que a literatura apresenta diversos tipos de tratamento para a hiperestesia dentinÃria, que variam desde procedimentos simples, que podem ser executados pelo prÃprio paciente, atà procedimentos complexos, que envolvem a combinaÃÃo de diferentes terapias. Os resultados do artigo 2 demonstraram que a aplicaÃÃo dos tratamentos propostos, inclusive o placebo, proporcionou reduÃÃo estatisticamente significante, imediata e mediata, da sensibilidade em resposta aos estÃmulos tÃtil e evaporativo (p<0,05). No entanto, nÃo houve diferenÃa estatisticamente significante entre os trÃs grupos estudados, independentemente do estÃmulo aplicado, tanto na avaliaÃÃo imediata quanto na mediata (p>0,05). Em conclusÃo, os resultados desses estudos indicam que o conhecimento acerca do mecanismo de ocorrÃncia da hiperestesia dentinÃria e dos agentes anti-hiperestÃsicos disponÃveis à indispensÃvel para a elaboraÃÃo de um tratamento eficiente. AlÃm disso, concluiu-se que os trÃs tratamentos utilizados no estudo clÃnico sÃo eficientes para a reduÃÃo da hiperestesia dentinÃria e que existe grande influÃncia do efeito placebo na reduÃÃo da sensibilidade dolorosa / Dentinal hypersensitivity is a complex sensorial condition which can cause considerable concern in the dental office. Despite the large number of different proposed kinds of treatment, there is no product or therapy reported in literature that could be considered ideal to eliminate this uncomfortable situation. The aim of this study, comprised by two manuscripts, was: (1) to critically review the literature related to the main evidences about the etiology and the management of dentinal hypersensitivity; (2) to evaluate the clinical performance of different dentine desensitizers in the treatment of dentinal hypersensitivity. In study 1, the scientific literature related to the issue was analyzed through the results of laboratory and clinical investigations searched using medline and manual tracing of references cited scientific papers. In study 2, a total of 164 teeth, from 30 patients with clinical diagnosis of moderate or severe dentinal hypersensitivity, were randomly divided into three groups and clinically evaluated according to the desensitizing treatment under study: gallium-aluminun-arsenide (GaAlAs) laser therapy, 3% potassium oxalate application and placebo gel application. Treatment sessions were performed at seven-day intervals for four consecutive weeks and the degree of sensitivity in response to tactile (probe) and evaporative (air blast) stimuli was assessed according to a visual analogue scale at baseline, immediately after and three months after the last treatment session. Data scores were submitted to Kruskal-Wallis statistical analysis (p=0.05) and were analyzed by dentinal hypersensitivity reduction for each observational moment in relation to baseline. The critical review presented in study 1 showed that the reviewed literature points out several treatment modalities ranging from simple procedures, which can be performed by the patient him/herself, to complex procedures that involve the combination of therapies. The results of study 2 demonstrated that the treatment of dentinal hypersensitivity performed with both active and control groups produced statistically significant reduction of pain in response to evaporative and tactile stimulation immediately after and three months after treatment (p<0.05). No significant differences among the three groups could be detected in both immediate and mediate evaluations irrespective of the applied stimulus (p>0.05). In conclusion, the results of these studies suggest that knowledge about the available desensitizing products and the factors involved in the mechanism of the dentinal hypersensitivity is indispensable in order to perform an effective treatment. Besides, it could be concluded that the three treatments performed in the clinical study were effective for treating dentinal hypersensitivity and that the placebo effect plays an important role in sensitivity reduction