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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
441

Développement d’un code numérique pour la simulation et l’étude de l’hydrodynamique et de la physico-chimie de milieux diphasiques incompressibles. Cas d’une goutte d’eau dans l’huile de paraffine / Development of a numerical code for the simulation and study of the hydrodynamics and the physical chemistry of incompressible two-phase media. Case of a droplet of water in paraffin oil

Fanzar, Abdelaziz 25 September 2014 (has links)
Depuis plusieurs décennies, une importante activité scientifique se concentre sur la description numérique, théorique ou expérimentale de l'hydrodynamique des écoulements multiphasiques. Ces écoulements sont caractérisés par l'existence d'interfaces, et d'une force à l'interface, la tension superficielle, séparant généralement deux fluides non miscibles. Un cas d'étude dans ce contexte est le problème du drainage d'une unique goutte dans une phase continue, l'ensemble étant soumis à la gravité. Ce système fait apparaître des écoulements récemment décrits pour une goutte d'eau dans l'huile de paraffine. Ce système constitue également un modèle simple pour l'étude des propriétés aux interfaces, Mais d'un point de vue numérique, se pose alors le problème de la stabilité des algorithmes pouvant être utilisés. Les effets aux interfaces impliquent en effet des domaines spatiaux très limités dans lesquels les grandeurs physiques entre les deux fluides sont discontinues. D'importants artéfacts numériques peuvent alors être générés dans les simulations et faire perdre la richesse de la physico-chimie du système considéré. Le problème de la simulation d'écoulements multiphasiques intéresse aussi bien le monde académique que le monde industriel. L'objectif de ce travail de thèse est donc d'implémenter les techniques numériques les plus récentes et de développer un code pour permettre la simulation de l'hydrodynamique de systèmes dispersés. Pour parvenir à ce but, il reste encore des problèmes algorithmiques importants à résoudre comme la prise en compte des effets thermocapillaires et thermosolutaux. Ces deux derniers points sont l'objet de cette thèse. / For several decades, an important scientific activity has focused on the numerical, theoretical and experimental hydrodynamics of drops. This work presents numerical results of a single droplet in the gravity field and in non-isothermal conditions. The simulation such a multiphase system is important in both academic and industrial world. This is particularly the case in the field of emulsions, wetting problems and evaporation. To achieve this goal, there are still important algorithmic problems due to the free moving interfaces and the description of capillary effects. Here, a Volume of Fluid technique has been implemented with high order temporal and spatial schemes to preserve the sharpness of the drop interface. The system under consideration is a simplified model consisting in a single water droplet in a continuous paraffin oil phase. These liquids are immiscible and non-compressible and the overall evolution is unsteady. Capillary contributions such as temperature and surfactant dependent surface tension are fully accounted for. This presentation is aimed to show the capabilities of VOF techniques for the simulations of unsteady multiphase systems in non-isothermal configurations. The role of the droplet initial position and temperature field is described with good numerical stability. There are still important problems remaining in the simulation of free interface systems with such a technique. Spurious currents induced by the description of capillarity can in particular come into play. But these latter can be controlled once the droplet average velocity due to drainage becomes large enough.
442

Avaliação das características do fango de Araxá-MG com finalidade de uso cosmético / Evaluation the characteristics of Fango from Araxá-MG with cosmetic purposes

Pereira, Fernanda Fialho 17 September 2008 (has links)
O tratamento cosmético facial e corporal que emprega o Fango vem sendo muito utilizado em clínicas de estética, com o intuito de melhorar a aparência da pele. A literatura científica carece de informações sobre alguns aspectos desta matéria-prima, como: as condições adequadas para sua coleta, preservando suas características químicas e microbiológicas; as especificações de qualidade da matéria-prima (física, química, microbiológica e toxicológica); e as metodologias analíticas de avaliação. A qualificação do Fango é primordial para o mesmo ser utilizado como matéria-prima de uso cosmético \"tal qual\" na pele ou veiculado em formulações cosméticas, a fim de alcançar a eficácia cosmética e garantir sua segurança de uso. Este trabalho visou a padronização do método de coleta do Fango na fonte e a das seguintes análises: física, físico-química, microbiológica, parasitológica, toxicológica do Fango provindo de Araxá-MG in natura e da lama negra (processada), com intuito de assegurar seu uso qualificado como matéria-prima em formulações cosméticas, uma vez que a literatura científica carece de estudos com este tipo de material. Os resultados obtidos quanto à segurança de uso foram satisfatórios, não ocorrendo a presença de microrganismos patogênicos tais como: Escherichia coli, coliformes fecais e totais, Staphylococcus aureus, Pseudomonas aeruginosa e Candida albicans (antes e depois da maturação), larva migrans e metais pesados. Os demais ensaios realizados para a caracterização do Fango como matéria-prima justificam sua aplicação em produtos cosméticos, como por exemplo, a presença do enxofre com potencial uso em formulações antissépticas e a argila tipo \"caulinita\" em preparações para diminuir a oleosidade da pele. / The facial and body cosmetic treatments applying the \"Fango\" can be seen nowadays on esthetic clinics\' catalogues. The scientific literature up nowadays does not have sufficient informations concerning this product, the correct procedures to collect it from the soil preserving its chemical and microbiological characteristics; the specifications on its physical, chemical, microbiological e toxicological qualities and the analytical methodologies involving on the it evaluation. The Fango\'s qualification is very important because it can be used alone (raw material) or incorporated in cosmetic formulations, in order to evaluate the safety and efficacy of final product. This is the only way it may be applied on cosmetics formulations designed to be applied on human skin. The aim of this research is to standard the collect conditions in thermal springs and standard such analysis: physical aspects, physic-chemical, microbiology, parasitological and toxicological of Thermal mud and Fango from Araxá-MG. The results obtained of this study showed that the Fango from Araxá-MG is safe to be applied in cosmetic formulations or direct on the human skin. The pathogenic microorganism such as: Escherichia coli, Staphylococcus aureus, Pseudomonas aeuruginosa and Candida Albicans were absent on the samples, and the same to Larva migrans and heavy metais. The physic-chemical analysis of Fango from Araxá-MG demonstrated its application in cosmetic products, as its capacity to improvement the skin\'s conditions, e.g. the presence of sulphur with antiseptic proprieties and organic compounds in order to use on the oily skin.
443

Relações quantitativas entre estrutura química e atividade biológica (QSAR/QSAR-3D) de compostos com potencial atividade antituberculose / Quantitative relationships between chemical structure and biological activity (QSAR/QSAR-3D) of compounds with potential anti-tuberculosis activity

Ishiki, Hamilton Mitsugu 25 July 2005 (has links)
A tuberculose (TB) é uma doença causada pelo Mycobacterium tuberculosis. De acordo com estimativas da Organização Mundial da Saúde, a tuberculose é responsável pela morte de ~2 a 3 milhões de pessoas/ano no mundo e nos próximos 15 anos cerca de 1 bilhão de pessoas deverão ser infectadas, e destas, aproximadamente 35 milhões deverão morrer. Apesar de existirem vários medicamentos sendo utilizados no tratamento da doença, constatasse o crescimento no número de casos devido, principalmente, às variedades resistentes do M. tuberculosis. Considerando-se o aparecimento de cepas resistentes em TB, recomenda-se que novos medicamentos e/ou alvos biológicos alternativos devam ser intensivamente pesquisados. A ribonucleotídeo redutase (RNR), por exemplo, é uma proteína de interesse, pois catalisa uma etapa importante e única na síntese de novo dos dNTPs, reduzindo o ribonucleosídeo 5\' -difosfato ao seu correspondente desoxirribonucleosídeo 5\' -difosfato. A RNR é importante na síntese do DNA, e portanto, na divisão das células. Esta enzima importante, que possuí 16% de homologia com a RNR de mamíferos, é um alvo potencial para o desenvolvimento de novos fármacos, com provável aplicação no tratamento do câncer, da malária e do tripanossoma. Sabe-se que diferentes classes de compostos, através de diferentes mecanismos de ação, inibem a RNR, incluindo as α-(N)-heterocíclicas carboxaldeído tiossemicarbazonas, um dos inibidores mais potentes da RNR. Sabe-se que alguns derivados da tiossemicarbazona, inibidoras da RNR de células tumorais, apresentam atividade frente o M. tuberculosis atuando provavelmente através do mesmo mecanismo, envolvendo a inibição da correspondente RNR. Neste contexto, nesta tese de doutorado, foram aplicadas diferentes abordagens de QSAR/QSAR-3D no estudo de 40 derivados da 2-piridino-carboxaldeído tiossemicarbazona, inibidores da RNR de células H.Ep.-2, retirados de literatura selecionada (French & Blanz-Jr. 1974). Estes compostos foram divididos em cinco séries, a saber: séries A, B, C, D, e E contendo, respectivamente, 40, 39, 30, 23 e 22 compostos, na tentativa de tornar estas séries estruturalmente mais homogêneas. Para cada série, foram criados três grupos de treinamento e os respectivos grupos de teste (I, II e III), visando-se avaliar o poder de predição dos modelos gerados através das análises de QSAR/QSAR-3D. Para as análises de QSAR clássico, foram utilizados como variáveis independentes, os descritores mais relevantes gerados através do programa DRAGON e, pré-selecionados por PLS. Considerando-se a ausência de informações sobre a estrutura cristalográfica da enzima RNR do M. tuberculosis, os estudos de QSAR-3D foram iniciados empregando-se metodologias propostas em CoMFA e, em CoMSIA, implementadas no programa SYBYL. Além destas, foi realizada a modelagem por homologia da RNR do M. tuberculosis, utilizando-se o programa WHATIF. Para as abordagens CoMFA e CoMSIA as geometrias otimizadas através do método semi-empírico AM1 foram alinhadas átomo-a-átomo e, através da similaridade dos respectivos campos estéricos e eletrostáticos, utilizando-se o programa SEAL. Nos dois procedimentos a geometria do composto não substituído, um dos mais ativos na série, foi utilizada como molde considerando-se a ausência de informações sobre a conformação bioativa. A modelagem da RNR por homologia foi realizada utilizando-se como molde as estruturas cristalográficas, respectivamente, do C. ammoniagenes (código PDB 1KGN) e da S. typhimurium (código PDB 1R2F), sambas apresentando valores de identidade superior a 65%. Mais recentemente foram publicados os dados cristalográficos para a cadeia beta (subunidade menor) da RNR do M. tuberculosis (código PDB 1UZR). Os modelos CoMFA e CoMSIA gerados apresentaram valores aceitáveis para os coeficientes de correlação de predição, com altos valores para os coeficientes de correlação ajustados e baixos valores para os erros padrões. Os melhores modelos CoMFA e CoMSIA foram obtidos considerando o grupo com substituintes apenas na posição 5 do anel piridínico. Razoáveis coeficientes de correlação de predição para os modelos CoMSIA com altos coeficientes de correlação de ajuste e baixos valores para os erros padrões forma obtidos. Os mapas de contorno gerados em CoMFA e CoMSIA sugerem que grupos aceptores de ligações de hidrogênio próximos ao nitrogênio do anel piridínico deverá aumentar o valor da atividade inibitória. Esta observação está em boa concordância com os dados da literatura, na qual a formação de um complexo entre a TSC e o íon Ferro foi sugerido para a inibição da RNR. Estes estudos deverão permitir um melhor entendimento sobre as características estruturais desta classe de TSC inibidoras da RNR, como agentes antitumorais, em termos dos campos estéricos, eletrostáticos, hidrofóbico, doador e aceptor de ligações de hidrogênio, bem como a contribuição para o desenvolvimento racional de novos inibidores para esta importante enzima. Adicionalmente, dois compostos preparados em nosso laboratório, demonstraram atividade frente o M. tuberculosis, em testes realizados in vivo. / Tuberculosis is an illness caused by Mycobacterium tuberculosis. Data from World Health Organization (WHO) estimates, that about 2-3 millions of human population died by Mycobacterium tuberculosis infection and that during the next 15 years about 1 billion will be infected and 35 million will certainly die. Although, in the clinic it was found several antiTBdrugs, these numbers will increase due several reasons including M. tuberculosis resistant strains. It has been stressed the importance of novel medicines and/or alternative biological targets research projects. It is known that Ribonucleotide reductase (RNR), is an enzyme that catalyses the rate limiting step in the de novo synthesis of dNTPs, reducing the ribonucleoside 5\'-diphosphates to the corresponding deoxyribonuc1eoside 5\' -diphosphates. RNR has a critical role in the DNA synthesis and, hence, cell division. This key enzyme, that shows 16% homology when compared with mammals RNR, is a potential target for drug design of cell growth inhibitors, with potential application in cancer therapy, antimalaria and trypanosome chemotherapy. It is known that different types of compounds or species by means of different mechanism pathways can show RNR inhibition, including α-(N)-heterocyclic carboxaldehydes thiosemicarbazones that are one of the most potent classes of RNR inhibitors. More than that, some of them, that shows activity against M. tuberculosis seems to follow the same mechanism pathways proposed to the thiosemicarbazones tumor cells activity that means, that they probably are RNR inhibitors. In this study, a series of 40 α-(N)-2-formyl-pyridine thiosemicarbazone derivatives tested against RNR of H.ep.-2-cells (human epidermoid carcinoma), taken from selected literature (French & Blanz-Jr. 1974), has quantitatively analyzed by means of several QSAR/3D-QSAR approaches. These compounds were divided into 5 individual subsets, namely A, B, C, D, and E, having 40, 39, 30, 23 e 22 compounds, respectively. This procedure has been done in order to achieve more structurally homogeneous subsets. For each set, three individual training and test sets (I,II and III) have been created in order to evaluate the predictivity power of the generated QSAR/3D-QSAR models. QSAR analysis have been done using descriptors generated by DRAGON program that have been further pre-selected by PLS procedures. Considering that crystallographic data of RNR M. tuberculosis are not available in the literature, 3D-QSAR studies have been done these applying, initially, CoMFA and CoMSIA approaches, implemented in SYBYL. Homology model studies have been performed with WHATIF program CoMFA e CoMSIA approaches used optimized geometry obtained by semi-empirical AM1 methods that have been aligned by two different methods. Rigid alignment, in which the compounds were fitted atom-by-atom onto a template, based on the root mean square fit. The N(l) and C(2) atoms of the pyridine moiety and the heavy atoms of thiosemicarbazone backbone of TSC were used as template structure. (2) Field based, in which the steric and electrostatic fields, generated by the SEAL program were considered in the alignment. In both procedures the unsubstituted 2-formylpyridine thiosemicarbazone in its syn conformation, has been taken as template. Homology RNR models were done using as template crystallographic data of ammoniagenes (1KGN) and S. typhimurium (1R2F) as template, respectively, with identity larger than 65%. More recent1y new crystallographic data have been published for the beta chain (smaller subunity) of RNR do M. tuberculosis (1UZR). CoMFA and CoMSIA generated models showed acceptable predictive correlation coefficients with high fitted correlation coefficients and low standard errors. Betler CoMFA and CoMSIA models have been derived considering a homogeneous subset of TSC substituted only at 5-position in pyridine ring. Reasonable predictive correlation coefficients for CoMSIA models with high fitted correlation coefficients and very low standard errors were obtained. The derived CoMFA and CoMSIA countour maps suggested that a hydrogen bond acceptor near the nitrogen pyridine ring could enhance inhibitory activity value. This observation is in good agreement with literature, in which a complex formation between TSC and iron ion has been suggested, to RNR inhibition. These studies are expected to enhance the understanding of the structural features of this class of TSC-RNR inhibitors as antitumor agents in terms of steric, electrostatic, hydrophobic and hydrogen donor and acceptor fields as well as to contribute to rational design of inhibitors of this key enzyme. Additionally, two compounds that have been prepared by us showed activity against M. tuberculosis using in vivo test system.
444

Relações quantitativas entre estrutura química e atividade biológica (QSAR/QSAR-3D) de compostos com potencial atividade antituberculose / Quantitative relationships between chemical structure and biological activity (QSAR/QSAR-3D) of compounds with potential anti-tuberculosis activity

Hamilton Mitsugu Ishiki 25 July 2005 (has links)
A tuberculose (TB) é uma doença causada pelo Mycobacterium tuberculosis. De acordo com estimativas da Organização Mundial da Saúde, a tuberculose é responsável pela morte de ~2 a 3 milhões de pessoas/ano no mundo e nos próximos 15 anos cerca de 1 bilhão de pessoas deverão ser infectadas, e destas, aproximadamente 35 milhões deverão morrer. Apesar de existirem vários medicamentos sendo utilizados no tratamento da doença, constatasse o crescimento no número de casos devido, principalmente, às variedades resistentes do M. tuberculosis. Considerando-se o aparecimento de cepas resistentes em TB, recomenda-se que novos medicamentos e/ou alvos biológicos alternativos devam ser intensivamente pesquisados. A ribonucleotídeo redutase (RNR), por exemplo, é uma proteína de interesse, pois catalisa uma etapa importante e única na síntese de novo dos dNTPs, reduzindo o ribonucleosídeo 5\' -difosfato ao seu correspondente desoxirribonucleosídeo 5\' -difosfato. A RNR é importante na síntese do DNA, e portanto, na divisão das células. Esta enzima importante, que possuí 16% de homologia com a RNR de mamíferos, é um alvo potencial para o desenvolvimento de novos fármacos, com provável aplicação no tratamento do câncer, da malária e do tripanossoma. Sabe-se que diferentes classes de compostos, através de diferentes mecanismos de ação, inibem a RNR, incluindo as α-(N)-heterocíclicas carboxaldeído tiossemicarbazonas, um dos inibidores mais potentes da RNR. Sabe-se que alguns derivados da tiossemicarbazona, inibidoras da RNR de células tumorais, apresentam atividade frente o M. tuberculosis atuando provavelmente através do mesmo mecanismo, envolvendo a inibição da correspondente RNR. Neste contexto, nesta tese de doutorado, foram aplicadas diferentes abordagens de QSAR/QSAR-3D no estudo de 40 derivados da 2-piridino-carboxaldeído tiossemicarbazona, inibidores da RNR de células H.Ep.-2, retirados de literatura selecionada (French & Blanz-Jr. 1974). Estes compostos foram divididos em cinco séries, a saber: séries A, B, C, D, e E contendo, respectivamente, 40, 39, 30, 23 e 22 compostos, na tentativa de tornar estas séries estruturalmente mais homogêneas. Para cada série, foram criados três grupos de treinamento e os respectivos grupos de teste (I, II e III), visando-se avaliar o poder de predição dos modelos gerados através das análises de QSAR/QSAR-3D. Para as análises de QSAR clássico, foram utilizados como variáveis independentes, os descritores mais relevantes gerados através do programa DRAGON e, pré-selecionados por PLS. Considerando-se a ausência de informações sobre a estrutura cristalográfica da enzima RNR do M. tuberculosis, os estudos de QSAR-3D foram iniciados empregando-se metodologias propostas em CoMFA e, em CoMSIA, implementadas no programa SYBYL. Além destas, foi realizada a modelagem por homologia da RNR do M. tuberculosis, utilizando-se o programa WHATIF. Para as abordagens CoMFA e CoMSIA as geometrias otimizadas através do método semi-empírico AM1 foram alinhadas átomo-a-átomo e, através da similaridade dos respectivos campos estéricos e eletrostáticos, utilizando-se o programa SEAL. Nos dois procedimentos a geometria do composto não substituído, um dos mais ativos na série, foi utilizada como molde considerando-se a ausência de informações sobre a conformação bioativa. A modelagem da RNR por homologia foi realizada utilizando-se como molde as estruturas cristalográficas, respectivamente, do C. ammoniagenes (código PDB 1KGN) e da S. typhimurium (código PDB 1R2F), sambas apresentando valores de identidade superior a 65%. Mais recentemente foram publicados os dados cristalográficos para a cadeia beta (subunidade menor) da RNR do M. tuberculosis (código PDB 1UZR). Os modelos CoMFA e CoMSIA gerados apresentaram valores aceitáveis para os coeficientes de correlação de predição, com altos valores para os coeficientes de correlação ajustados e baixos valores para os erros padrões. Os melhores modelos CoMFA e CoMSIA foram obtidos considerando o grupo com substituintes apenas na posição 5 do anel piridínico. Razoáveis coeficientes de correlação de predição para os modelos CoMSIA com altos coeficientes de correlação de ajuste e baixos valores para os erros padrões forma obtidos. Os mapas de contorno gerados em CoMFA e CoMSIA sugerem que grupos aceptores de ligações de hidrogênio próximos ao nitrogênio do anel piridínico deverá aumentar o valor da atividade inibitória. Esta observação está em boa concordância com os dados da literatura, na qual a formação de um complexo entre a TSC e o íon Ferro foi sugerido para a inibição da RNR. Estes estudos deverão permitir um melhor entendimento sobre as características estruturais desta classe de TSC inibidoras da RNR, como agentes antitumorais, em termos dos campos estéricos, eletrostáticos, hidrofóbico, doador e aceptor de ligações de hidrogênio, bem como a contribuição para o desenvolvimento racional de novos inibidores para esta importante enzima. Adicionalmente, dois compostos preparados em nosso laboratório, demonstraram atividade frente o M. tuberculosis, em testes realizados in vivo. / Tuberculosis is an illness caused by Mycobacterium tuberculosis. Data from World Health Organization (WHO) estimates, that about 2-3 millions of human population died by Mycobacterium tuberculosis infection and that during the next 15 years about 1 billion will be infected and 35 million will certainly die. Although, in the clinic it was found several antiTBdrugs, these numbers will increase due several reasons including M. tuberculosis resistant strains. It has been stressed the importance of novel medicines and/or alternative biological targets research projects. It is known that Ribonucleotide reductase (RNR), is an enzyme that catalyses the rate limiting step in the de novo synthesis of dNTPs, reducing the ribonucleoside 5\'-diphosphates to the corresponding deoxyribonuc1eoside 5\' -diphosphates. RNR has a critical role in the DNA synthesis and, hence, cell division. This key enzyme, that shows 16% homology when compared with mammals RNR, is a potential target for drug design of cell growth inhibitors, with potential application in cancer therapy, antimalaria and trypanosome chemotherapy. It is known that different types of compounds or species by means of different mechanism pathways can show RNR inhibition, including α-(N)-heterocyclic carboxaldehydes thiosemicarbazones that are one of the most potent classes of RNR inhibitors. More than that, some of them, that shows activity against M. tuberculosis seems to follow the same mechanism pathways proposed to the thiosemicarbazones tumor cells activity that means, that they probably are RNR inhibitors. In this study, a series of 40 α-(N)-2-formyl-pyridine thiosemicarbazone derivatives tested against RNR of H.ep.-2-cells (human epidermoid carcinoma), taken from selected literature (French & Blanz-Jr. 1974), has quantitatively analyzed by means of several QSAR/3D-QSAR approaches. These compounds were divided into 5 individual subsets, namely A, B, C, D, and E, having 40, 39, 30, 23 e 22 compounds, respectively. This procedure has been done in order to achieve more structurally homogeneous subsets. For each set, three individual training and test sets (I,II and III) have been created in order to evaluate the predictivity power of the generated QSAR/3D-QSAR models. QSAR analysis have been done using descriptors generated by DRAGON program that have been further pre-selected by PLS procedures. Considering that crystallographic data of RNR M. tuberculosis are not available in the literature, 3D-QSAR studies have been done these applying, initially, CoMFA and CoMSIA approaches, implemented in SYBYL. Homology model studies have been performed with WHATIF program CoMFA e CoMSIA approaches used optimized geometry obtained by semi-empirical AM1 methods that have been aligned by two different methods. Rigid alignment, in which the compounds were fitted atom-by-atom onto a template, based on the root mean square fit. The N(l) and C(2) atoms of the pyridine moiety and the heavy atoms of thiosemicarbazone backbone of TSC were used as template structure. (2) Field based, in which the steric and electrostatic fields, generated by the SEAL program were considered in the alignment. In both procedures the unsubstituted 2-formylpyridine thiosemicarbazone in its syn conformation, has been taken as template. Homology RNR models were done using as template crystallographic data of ammoniagenes (1KGN) and S. typhimurium (1R2F) as template, respectively, with identity larger than 65%. More recent1y new crystallographic data have been published for the beta chain (smaller subunity) of RNR do M. tuberculosis (1UZR). CoMFA and CoMSIA generated models showed acceptable predictive correlation coefficients with high fitted correlation coefficients and low standard errors. Betler CoMFA and CoMSIA models have been derived considering a homogeneous subset of TSC substituted only at 5-position in pyridine ring. Reasonable predictive correlation coefficients for CoMSIA models with high fitted correlation coefficients and very low standard errors were obtained. The derived CoMFA and CoMSIA countour maps suggested that a hydrogen bond acceptor near the nitrogen pyridine ring could enhance inhibitory activity value. This observation is in good agreement with literature, in which a complex formation between TSC and iron ion has been suggested, to RNR inhibition. These studies are expected to enhance the understanding of the structural features of this class of TSC-RNR inhibitors as antitumor agents in terms of steric, electrostatic, hydrophobic and hydrogen donor and acceptor fields as well as to contribute to rational design of inhibitors of this key enzyme. Additionally, two compounds that have been prepared by us showed activity against M. tuberculosis using in vivo test system.
445

Composição e qualidade de méis de abelhas (Apis mellifera) e méis de abelha Jataí (Tetragonisca angustula) / Composition and quality of honeys from bees (Apis mellifera) and stingless bees honeys (Jataí bee or Tetragonisca angustula)

Sousa, Graziela Leal 06 November 2008 (has links)
O mel é um alimento de uso milenar, açucarado de fácil digestão, que constitui uma importante fonte de energia, contribuindo para o equilíbrio do processo biológico do corpo humano, sendo elaborado a partir da desidratação e transformação do néctar das flores nativas pelas abelhas produtoras. Para que o mel seja comercializado para o consumo humano, ele precisa atender aos requisitos mínimos de identidade e qualidade exigidos pela Legislação Brasileira. No Brasil a criação de abelhas é dividida em duas práticas distintas, a Apicultura tradicional, que utiliza as abelhas Apis mellifera e a Meliponicultura que utiliza as abelhas sem ferrão como a Jataí (Tetragonisca angustula). Os méis de abelhas sem ferrão tem maior valor comercial comparado ao mel tradicional, entretanto são comercializados sem uma legislação própria. Na literatura existem poucos trabalhos que tratam da composição destes tipos de méis que são popularmente conhecidos por suas propriedades benéficas à saúde. Em vista do exposto acima, o objetivo deste presente trabalho foi o de comparar a composição e a qualidade de méis de Apis mellifera com os de abelhas sem ferrão da espécie Tetragonisca angustula, popularmente conhecida como Jataí. Para tanto as amostras de méis foram obtidas de colméias de Apis mellifera e de Tetragonisca angustula de uma mesma região botânica, o que foi possível constatar que os méis de abelha Jataí apresentaram maior diversidade botânica em relação aos méis de Apis. Neste trabalho foram utilizados os métodos de avaliação estabelecidos pela Legislação Brasileira para qualidade de mel de Apis mellifera e os valores sugeridos para méis de mellponíneos do Brasil pe10s pesquisadores VILLAS - BOAS e MALASPINA (2005). A maioria das amostras de Apis apresentaram-se dentro da legislação vigente, enquanto méis Jataí apresentaram os parâmetros: umidade (23,40 -25,60%), acidez (21,65 - 63,85 mE/Kg) e açúcares redutores (44,78 - 67,54%) e sacarose aparente (0,43 - 1,60%) fora dos padrões estabelecido pela legislação vigente para os méis de Apis mellifera. No entanto, encontram-se dentro dos valores sugeridos para méís de meliponíneos brasileiros, pelos pesquisadores acima mencionados. Além das análises físico-químicas tradicionais e a análise polínica também foi determinada a composição nutricional, sendo que o mel de Apis apresentou maior de valor energético (43,58- 66,32 Kcal) em relação aos méis de Jataí (36,83 - 60,52 Kcal) (p<0,05). Também foram determinados os açúcares por CLAE, condutividade elétrica (uS/cm-1) e a análise de cor (mmPfund). As amostras de Apis mellifera apresentaram maior o teor glicose (%), frutose (%) e condutividade elétrica (uS/cm-1) em relação aos méis de Jataí Em relação as análises de cor notou-se maior predominância da coloração âmbar-claro, mas amostras analisadas. / Honey is considered as a food that provides energy, being elaborated from the dehydration and transformation of the nectar of the flowers by the bees. For the human consumption, honey needs to attend the minimum requirements of identity and quality demanded by the regulation. In Brazil beekeepers can be divided in two practical distinct ones: the traditional ones, which use Apis mellifera bees and the Meliponiculture which uses stingless bees such as Jataí bee (Tetragonisca angustula). There are no identity and quality parameters or regulation for this type of honey. Honey from of stingless bees are more expensive compared with the traditional honey, however their are commercialized without a proper regulation. In literature few works were found regarding the composition of these types of honey which are popularly known by its beneficiaI properties to human health. The objective of the present work is to compare the composition and quality of honey from Apis mellifera and from stingless bees (Tetragonisca angustula), popularly known as Jataí bee. Samples of honey were obtained from Apis mellifera and Tetragonisca angustula bees in the same botanical region. In this work the methods used were based on the Brazilian Regulation for quality control of honey from Apis mellifera and the values suggested for honeys of meliponíneos of Brazil for researchers VILLAS-BOAS and MALASPINA (2005). The majority of the samples of Apis had presented in accordance with the regulation while the Jataí honeys had presented: humidity (23,40 - 25.60%), acidity (21,65 - 63,85 mE/Kg) and reducing sugars (44,78 - 67.54%) are out of the standards for honeys of Apis mellifera. However, they are in accordance with the values suggested for honeys of Brazilian meliponíneos. The physicochemical, polinic and nutritional analysis were determined, and the honey of Apis bee presented greater amount of energy value (43,58 - 66,32 Kcal) in relation to the honeys of Jataí bee (36,83 - 60,52 Kcal) (p<O,05). The sugars for HPLC, electric conductivity (uS/cm-1) and analysis of color (mmPfund) were determined. Samples of Apis mellifera had presented greater values for glucose (%), frutose (%) and electric conductivity (uS/cm-1) in relation to the honeys from Jataí (p<0,05). Regarding the color analyses, it was predominance of the coloration clear -amber.
446

[en] ROBOTIC SYSTEM FOR MONITORING WATER QUALITY IN LENTIC ENVIRONMENTS / [pt] SISTEMA ROBÓTICO PARA MONITORAMENTO DA QUALIDADE DA ÁGUA EM AMBIENTES LÊNTICOS

MARCOS AURELIO PINTO MARZANO JR 18 February 2019 (has links)
[pt] Nas últimas décadas, a crescente conscientização ambiental levou ao reconhecimento da necessidade do uso responsável dos recursos hídricos. Para garantir isso, a boa gestão de reservatórios hídricos requer um monitoramento ambiental adequado, com medições confiáveis dos parâmetros de qualidade da água em vários pontos do reservatório, permitindo o controle da qualidade da água e seus impactos na fauna, flora e comunidades ribeirinhas dos reservatórios. O monitoramento das variáveis ambientais dos reservatórios é atualmente realizado por processo tradicional de coleta manual. Infelizmente, no Brasil, as iniciativas de produzir um sistema robótico aquático com tecnologia nacional e de baixo custo, quando comparado a equivalentes importados, são ainda raras e se restringem a algumas poucas instituições acadêmicas, não tendo sido localizado nenhum fabricante comercial deste tipo de veículo no país. Visando preencher esta lacuna, o presente trabalho teve como objetivo o desenvolvimento do protótipo de um sistema robótico aquático capaz de se locomover autonomamente em lagoas, lagos e reservatórios, coletando informações físico-químicas da água e armazenando estes dados na memória. Além disso, foi incluído no protótipo uma câmera de vídeo, sistema de iluminação e um sistema de controle remoto, objetivando o controle pela equipe em terra. Nos testes realizados em dias ensolarados e chuvosos, o robô apresentou boa dirigibilidade, estabilidade e manobrabilidade. O vaso de pressão do sistema robótico resistiu às pressões necessárias durante os testes, a eletrônica conseguiu atender as especificações de projeto e o software conseguiu estabelecer um controle de navegação, cumprindo o trajeto de uma rota estabelecida. / [en] In recent decades, the growing environmental awareness has led to the recognition of the need for responsible use of water resources. To ensure this, the good management of water reservoirs requires adequate environmental monitoring, with reliable measurements of water quality parameters in various parts of the reservoir, allowing the control of water quality and its impacts on fauna, flora and riverine communities of the reservoirs. Monitoring environmental variables of the reservoirs is currently performed by traditional process of manual collection. Unfortunately, in Brazil, initiatives to produce a water robotic system with national and low cost technology, compared to imported equivalents, are still rare and restricted to a few academic institutions, and no commercial manufacturer of this type of vehicle was found in the country. Aiming to fill this gap, the main objective of this study was to develop a prototype of a water robotic system capable of autonomously navigate in ponds, lakes and reservoirs, collecting physicochemical information of water and storing this data in memory. Moreover, a video camera, illumination and a remote control system were included in the prototype, allowing the team on the ground to control the prototype. In tests conducted in sunny and rainy days, the robot presented good handling, stability and maneuverability. The robotic system pressure vessel resisted pressures required during testing, the electronics met the design specifications and the software was able to establish a navigation control, fulfilling the path of an established route.
447

Sinteza, strukturna, fizičko-hemijska i biološka karakterizacija novih N-heterocikličnih liganada i njihovih kompleksa sa jonima prelaznih metala / Synthesis, structural, physico-chemical and biological characterization of N-heterocyclic ligands and their complexes with transition metal ions

Mađari Jožef 08 October 2018 (has links)
<p>Opisane&nbsp; su&nbsp; sinteze&nbsp; novih&nbsp; liganada&nbsp; bis(ftalazin-1hidrazon)-2,6-diacetilpiridna&nbsp; (Hz<sub>2</sub>DAP&middot;2HCl),&nbsp; bis(3-hlorpiridazin-6-hidrazon)-2,6-diacetilpiridina (Hp<sub>2</sub>DAP),&nbsp; 3-hlorpiridazin-6-hidrazon&nbsp; di(2-piridil) ketona&nbsp; (HpDPK),&nbsp; ftalazin-1-hidrazon&nbsp; di(2-piridil)<br />ketona&nbsp; (HzDPK)&nbsp; i&nbsp; ftalazin-1-hidrazon&nbsp; piridin-2-karbaldehida&nbsp; (HzPY).&nbsp; Zajedničko&nbsp; svojstvo&nbsp; dobijenih liganada&nbsp; je&nbsp; &scaron;to&nbsp; sadrže&nbsp; piridinski&nbsp; i&nbsp; diazinski&nbsp; prsten&nbsp; i sadrže&nbsp; samo&nbsp; donorne&nbsp; atome&nbsp; azota.&nbsp; Tokom&nbsp; nastajanja kompleksa dolazi do deprotonacije liganada. Svi ligandi su&nbsp; okarakterisani&nbsp; elementalnom&nbsp; analizom, termoanalitičkim&nbsp; metodama&nbsp; i&nbsp; metodom&nbsp; IR spektroskopije,&nbsp; dok&nbsp; neki&nbsp; i&nbsp; metodom&nbsp; NMR spektroskopije&nbsp; kao&nbsp; i&nbsp; rendgenskom&nbsp; strukturnom analizom.Za&nbsp; sintezu&nbsp; koordinacionih&nbsp; jedinjenja&nbsp; primenjeni&nbsp; soli Co(II),&nbsp; Ni(II),&nbsp; Cu(II)&nbsp; i&nbsp; Zn(II).&nbsp; Dobijeni&nbsp; kompleksi su okarakterisani&nbsp; elementalnom&nbsp; analizom, konduktomerijskim&nbsp; i&nbsp; magnetnim&nbsp; merenjima,&nbsp; IR spektroskopijom i termoanalitičkim metodama. Barem jedan&nbsp; kompleks&nbsp; iz&nbsp; svake&nbsp; serije&nbsp; je&nbsp; okarakterisan&nbsp; i rendgenskom strukturnom analizom. Urađena&nbsp; su&nbsp; i&nbsp; ispitivanja&nbsp; antimikrobne&nbsp; aktivnosti odabranih&nbsp; jedinjenja&nbsp; prema&nbsp; predstavnicima&nbsp; grampozitivnih i gram-negativnih bakterija i kulturu kvasca. Pored&nbsp; toga,&nbsp; urađena&nbsp; su&nbsp; i&nbsp; ispitivanja&nbsp; citotoksične,antiproliferativne&nbsp; i&nbsp; inhibitorne&nbsp; aktivnosti&nbsp; jedinjenja prema&nbsp; roditeljskim&nbsp; i&nbsp; multirezistentnim&nbsp; T-limfomnim ćelijama&nbsp; kancera.&nbsp; Utvrđeno&nbsp; je&nbsp; da&nbsp; neka&nbsp; jedinjenja pokazuju&nbsp; izrazito&nbsp; mikrobicidno,&nbsp; citotoksično, antiproliferativno i inhibitorno dejstvo.</p> / <p>The synthesis of new ligands dihydrochloride salt of 2,6-diacetylpyridne&nbsp;&nbsp; bis(phthalazine-1hydrazone) (Hz<sub>2</sub>DAP&bull;2HCl),&nbsp; 2,6-diacetylpiridine&nbsp; bis(3- chloropyridazine-6-hydrazone)&nbsp; (Hp<sub>2</sub>DAP),&nbsp; di(2-pyridyl)ketone&nbsp; 3-chloropyridazine- 6-hydrazone (HpDPK),&nbsp; di(2-pyridyl)ketone&nbsp; phthalazine-1-hydrazone&nbsp; (HzDPK)&nbsp; and&nbsp; &nbsp; pyridine-2-carbaldehide phthalazine-1-hydrazone&nbsp; (HzPY)&nbsp; have&nbsp; been described. All the ligands contain pyridine and diazine core and all of them have only nitrogen donor atoms. During the complex formation the deprotonation of ligands takes&nbsp; places.&nbsp; All&nbsp; of&nbsp; the&nbsp; ligands&nbsp; have&nbsp; been characterized&nbsp; by&nbsp; elemental&nbsp; analysis,thermoanalytical&nbsp; methods&nbsp; and&nbsp; IR&nbsp; spectroscopy.&nbsp; In some&nbsp; cases&nbsp; also&nbsp; by&nbsp; NMR&nbsp; spectroscopy&nbsp; and&nbsp; X-ray structural analysis.Co(II), Ni(II), Cu(II) and Zn(II) salts were&nbsp; used for the synthesis&nbsp; of&nbsp; the&nbsp; coordinational&nbsp; compounds.&nbsp; The obtained complexes were characterized by elemental analysis,&nbsp; molar&nbsp; conductivity&nbsp; and&nbsp; magnetic measurements,&nbsp; IR&nbsp; spectroscopy&nbsp; and thermoanalytical&nbsp; methods.&nbsp; At&nbsp; least&nbsp; one complex&nbsp; of each&nbsp; series&nbsp; were&nbsp; characterized&nbsp; by&nbsp; X-ray&nbsp; structural analysis.The antimicrobial activity of some of the compounds toward&nbsp; Gram-positive/Gram- negative&nbsp; bacteria furthermore,&nbsp; the&nbsp; cytotoxic,&nbsp; antiproliferative&nbsp; and inhibitory&nbsp; activity&nbsp; toward&nbsp; sensitive&nbsp; parental&nbsp; andmultiresistant&nbsp; T-lymphoma&nbsp; cancer&nbsp; cells&nbsp; have&nbsp; also been carried out. It&nbsp; can&nbsp; be&nbsp; concluded&nbsp; that&nbsp; some&nbsp; of&nbsp; the&nbsp; compounds exhibit&nbsp; outstanding&nbsp; antimicrobial,&nbsp; cytotoxic, antiproliferative, and inhibitory activity.</p>
448

Kompleksi nekih prelaznih metala sa Šifovim bazama aminogvanidina / Some transition metal complexes with Schiff bases of aminoguanidine

Radanović Mirjana 29 October 2015 (has links)
<p>&nbsp;&nbsp; U ovoj doktorskoj disertaciji opisane su sinteze novih kompleksa prelaznih metala sa piridoksiliden-&nbsp; (PLAG), odnosno saliciliden-aminogvanidinom (SALAG). Dobijeni<br />kompleksi su okarakterisani elementalnom analizom, IR spektrima, konduktometrijskim i magnetnim merenjima, a većina i rendgenskom<br />strukturnom analizom. Osim toga, dobijene su i nove forme ovih &Scaron;ifovih baza, i to u vidu monokristala, čime su omogućena ispitivanja njihovih&nbsp; molekulskih i kristalnih struktura, kao i uporedna analiza sa koordinovanim ligandima.<br />&nbsp; &nbsp; Sa PLAG je sintetisano 7 novi&nbsp; kompleksa Cu(II), a pored toga po prvi put su<br />izolovani mono i bis(ligand) kompleksi Fe(III) i Co(III), mono(ligand) kompleksi&nbsp; V(V), kao&nbsp; i jedan kompleks Zn(II) u kojem ovaj potencijalno tridentatni&nbsp;<em> ONN&nbsp;</em> ligand,&nbsp; u<br />monoprotonovanoj formi,&nbsp; ima ulogu kontra-jona. Sa stanovi&scaron;ta geometrije zajedničko za izolovane komplekse Cu(II) i V(V) je da imaju kvadratno-piramidalnu strukturu, sa izuzetkom jednog kvadratno-planarnog kompleksa Cu(II), dok je u kompleksima Fe(III) i Co(III) nađeno očekivano oktaedarsko okruženje centralnog<br />jona. Pored ovih, sintetisano je i pet novih kompleksa sa SALAG, od kojih su dva<br />kompleksa Cu(II) i kompleks V(V) okarakterisani rendgenskom strukturnom<br />analizom, dok je mikrokristalnim bis(ligand) kompleksima Co(III) i Ni(III) na osnovu<br />fizičko-hemijskih karakteristika predložena odgovarajuća struktura.<br />&nbsp;&nbsp; Zajedničko za obe opisane &Scaron;ifove baze je da se koordinuju na&nbsp;<em> ONN&nbsp; </em>tridentatni način, i to preko atoma kiseonika deprotonovane fenolne grupe i atoma azota azometinske i imino grupe AG fragmeta. Posebno je nagla&scaron;eno da su&nbsp; sa<br />PLAG izolovana dva dimerna kompleksa Cu(II) u kojima je po prvi put nađena tetradentatna koordinacija ovog&nbsp; liganda, u koju je dodatno uključen atom kiseonika hidroksimetil-grupe PL-ostatka. Za razliku od SALAG, koji je u izolovanim kompleksima koordinovan isključivo kao monoanjon, nastao deprotonacijom fenolne<br />OH-grupe, za PLAG je osim ove, potvđena koordinacija u neutralnoj, zwitter-jonskoj, ali i dvostruko deprotonovanoj formi. Zwitter-jonska forma liganda nastaje migracijom atoma vodonika sa fenolnog hidroksila na piridinski atom azota PL-ostatka, dok deprotonacijom piridinskog ili hidrazinskog atoma azota, odnosno oba pomenuta atoma nastaju monoanjon i dianjon helatnog liganda, respektivno.<br />&nbsp;&nbsp; Na kraju, urađena su&nbsp; i ispitivanja antimikrobne aktivnosti odabranih jedinjenja<br />prema predstavnicima grampozitivnih i gramnegativnih bakterija, kao i dve kulture<br />kvasca. Tom prilikom nije utvrđena nikakva inhibitorna aktivnost&nbsp;&nbsp; prema primenjenim<br />bakterijskim sojevima, dok su u slučaju kvasaca izvesno mikrobicidno dejstvo pokazali samo kompleksi Cu(II).</p> / <p>This PhD thesis describes the syntheses of some new transition metal complexes with&nbsp; pyridoxilidene-&nbsp; (PLAG) and salicylideneaminoguanidine (SALAG). Obtained&nbsp; complexes are characterized by&nbsp;&nbsp; elemental analysis, IR&nbsp; spectroscopy,&nbsp; conductometric and magnetic measurements. Besides, the structural analysis of majority of the obtained complexes was performed. Some new forms of these Schiff&nbsp; bases are synthesized in form of single crystals, which made their X-ray analysis as well as comparison with coordinated forms possible.</p><p>With PLAG, 7 new Cu(II) complexes were obtained and for the first time mono and bis(ligand) complexes of Fe(III) and Co(III) as well&nbsp; mono(ligand)&nbsp; complexes&nbsp; of V(V) were isolated. Furthermore,&nbsp; the structure of Zn(II) complex in which PLAG in its monocationic form has a role of counter ion is presented. With the exception of one Cu(II) complex, all reported Cu(II) and V(V) complexes have a square-pyramidal geometry, whilst&nbsp; Fe(III)&nbsp; and Co(III)&nbsp; are situated in octahedral surroundings. Also, five new complexes of Cu(II), Co(III), Ni(II) and V(V) with SALAG were synthesized. In both&nbsp; Cu(II) complexes and V(V) complex the expected coordination mode and geometry were confirmed by X-ray analysis, while octahedral structure of bis(ligand) complexes with Co(III) and Ni(II) was proposed based on results of physico-chemical&nbsp; characterization.</p><p>Both PLAG and SALAG coordinate the metal ion in tridentate&nbsp; ONN&nbsp; manner, through the oxygen atom of deprotonated phenolic group and nitrogen atoms&nbsp; of azomethine and imino groups of AG moiety. It is also emphasized that in two dimeric Cu(II) complexes with PLAG tetradentate coordination mode was found, in which the oxygen atom of hydroxymethyl group of PL residue was additionally involved. Unlike SALAG, which is coordinated as monoanion in all of the examined complexes, PLAG can have one of three degrees of deprotonation. Zwitter-ion of PLAG is formed by migration of H-atom from phenolic oxygen to pyridine nitrogen, while the deprotonation of pyridine or/and hydrazine nitrogen, makes it mono-and dianion, respectively.</p><p>Also, microbiological tests on the selected compounds were preformed. Namely, antimicrobial activity of these compounds against some gram-positive and gram-negative bacteria, as well as some yeast cultures was examined and none of the samples showed antimicrobial activity against bacteria, whilst only Cu(II) complexes showed certain inhibitory effect against yeasts.</p>
449

Investigating industrial effluent impacts on municipal wastewater treatment plant

Iloms, Eunice Chizube 07 1900 (has links)
Industrial effluents with high concentrations of heavy metals are widespread pollutants of great concerns as they are known to be persistent and non-degradable. Continuous monitoring and treatment of the effluents become pertinent because of their impacts on wastewater treatment plants. The aim of this study is to determine the correlation between heavy metal pollution in water and the location of industries in order to ascertain the effectiveness of the municipal waste water treatment plant. Heavy metal identification and physico-chemical analysis were done using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and multi-parameter probe respectively. Correlation coefficients of the measured values were done to investigate the effect of the industrial effluents on the treatment plants. Heavy metal resistant bacteria were identified and characterised by polymerase chain reaction and sequencing. Leeuwkuil wastewater treatment plants were effective in maintaining temperature, pH, and chemical oxygen demand within South Africa green drop and SAGG Standards whereas the purification plant was effective in maintaining the values of Cu, Zn, Al, temperature, BOD, COD, and TDS within the SANS and WHO standard for potable water. This findings indicated the need for the treatment plants to be reviewed.The industrial wastewater were identified as a point source of heavy metal pollution that influenced Leeuwkuil wastewater treatment plants and the purification plants in Vaal, Vereenining South Africa. Pseudomonas aeruginosa, Serratia marcescens, Bacillus sp. strain and Bacillus toyonensis that showed 100% similarity were found to be resistant to Al, Cu, Pb and Zn. These identified bacteria can be considered for further study in bioremediation. / Environmental Sciences / M. Sc. (Environmental Science)
450

Etude de la dynamique hydro-sédimentaire de fleuves tropicaux par mesures in situ et de télédétection : le cas du Maroni, de l'Oyapock et de l'Orénoque / Study of the hydro-sedimentary dynamics of tropical rivers by measures in situ and remote sensing : the case of the Maroni, Oyapock and Orinoco

Gallay, Marjorie 17 October 2017 (has links)
L'eau des fleuves, des rivières, des lacs et des réservoirs ne représente que 0,26 % des 2,5 % (35 millions de km3) d'eau douce disponibles à l’état liquide sur Terre, or sa qualité et quantité ont fortement diminué ces dernières années. Sa dégradation a des conséquences sur l'agriculture, la santé, l'environnement et l'économie des territoires et est aujourd'hui au centre des préoccupations sociétales. Les objectifs de la présente thèse sont pour trois fleuves localisés dans le Bouclier des Guyanes, au nord de l'Amérique du Sud (le Maroni, l'Oyapock, l'Orénoque): (i) d'utiliser et d'adapter des outils novateurs de télédétection pour suivre et quantifier, sur du long terme, leurs charges sédimentaires en suspension, (ii) d'évaluer l'existence de tendances spatio-temporelles, ainsi que de ruptures dans les chroniques de données, (iii) de quantifier la part organique et minérale de ces charges, (iv) d'apprécier le rôle des facteurs naturels (débits et précipitations) et anthropiques (surfaces urbaines, agricoles et minières) sur les tendances observées et enfin, (v) de discuter de seuils de charges pour le suivi de la qualité de l'eau. Les résultats ont montré qu'il est possible de suivre les concentrations de matières en suspension, pour les fleuves Orénoque et Maroni avec une erreur relative de 32 et 25% respectivement. Sur la période 2000-2016, des tendances spatio-temporelles régulières ont été observées pour l'Orénoque, alors qu'elles sont en augmentation pour le Maroni avec une rupture en 2009 et en diminution pour l'Oyapock depuis 2008 (données in situ). Un lien fort avec l'augmentation de la déforestation pour les surfaces minières et les précipitations est observé pour le Maroni alors que pour l'Oyapock les tendances sont liées aux débits.Pour les deux années d'études (2014-2016), les charges minérales ont représenté la plus forte fraction des particules transportées dans les eaux du Maroni au Saut Hermina (en moyenne 93 %) et de l'Oyapock au Saut Maripa (en moyenne 82 %) avec une grande variabilité selon les mois de la teneur en carbone dans les matières transportées et pour les deux fleuves. Enfin, les rapports C/N et C/Chl-a ont dévoilé des matières organiques d'origine principalement endogène avec une forte biomasse chlorophyllienne surtout durant les basses eaux. / The water of rivers, lakes and reservoirs represents only 0.26 % of the 2.5 % (35 million of km3) of fresh water available on the liquid state on Earth, but its quality and quantity strongly decreased these last years. Her degradation has consequences on the farming, the health, the environment and the economy of territories and is now in the center of the societal concerns. The objectives of the present thesis are for three rivers located in the Guiana Shield, in the North of South America (the Maroni, the Oyapock, the Orinoco): i) to use and to adapt innovative tools of remote detection to follow and quantify, on the long term, their sedimentary loads, ii) to estimate the existence of spatiotemporal trends, as well as breaks in the chronicles of data, iii) to quantify the organic and mineral part of these loads, iv) to appreciate the role of the natural (discharge and precipitation) and the anthropological factors (urban, agricultural and mining surfaces) on the observed trends and finally, v) to discuss thresholds of concentrations for the quality monitoring of the river water.The results showed that it is possible to follow the concentrations of suspension materials, for rivers Maroni and Orinoco with a relative error of 25 and 32 % respectively. Over the period 2000-2016, regular spatiotemporal trends were observed for the Orinoco, while they are increasing for Maroni with a break in 2009 and in decrease for the Oyapock since 2008 (in situ data). A strong link with the increase of the deforestation for the mining surfaces and the precipitation is observed for the Maroni catchment while for the Oyapock the trend is explained by the specific water discharge.For two years of studies (2014-2016), the mineral loads represented the strongest fraction of particles transported in the Maroni River at Saut Hermina (on average 93 %) and in the Oyapock River at Saut Maripa (on average 82 %) with a high variability according to the months of the content in carbon in the transported materials and for both rivers. Finally, report C/N and C/Chl-a revealed organic matters of mainly endogenous origin with a strong chlorophyll biomass and especially during the low water period.

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