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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.
601

Avaliação da solubilidade e da permeabilidade intestinal de fármacos antirretrovirais. Aplicações na classificação biofarmacêutica / Evaluation of solubility and intestinal permeability of antiretroviral drugs. Biopharmaceutical classification

Thaisa Marinho Pereira 08 March 2012 (has links)
A biodisponibilidade de um fármaco é o fator determinante da eficácia clínica e depende principalmente das seguintes etapas: liberação da substância ativa a partir da forma farmacêutica e absorção. Assim, o controle da extensão e da velocidade de absorção de um fármaco administrado por via oral depende basicamente de dois aspectos: solubilidade nos líquidos fisiológicos e permeabilidade através das membranas biológicas. Fundamentado nestas características, o Sistema de Classificação Biofarmacêutica (SCB) foi proposto como ferramenta que permite a classificação dos fármacos e tem como finalidade auxiliar nas bioisenções e na predição da biodisponibilidade in vivo. Neste sentido, o presente trabalho teve como objetivo avaliar a solubilidade da estavudina e a permeabilidade intestinal de fármacos antirretrovirais por meio do modelo de perfusão in situ. Os meios empregados nos estudos de solubilidade e dissolução intrínseca foram: água purificada, tampão pH 1,2, tampão pH 4,5, tampão pH 6,8 e tampão pH 7,5. Para a determinação da solubilidade pelo método do equilíbrio (técnica shake-flask), quantidades conhecidas do fármaco foram adicionadas em cada meio até atingir a saturação e esta mistura foi submetida à agitação de 150 rpm por 72 horas a 37°C. Para os ensaios de dissolução intrínseca, quantidade conhecida de estavudina foi compactada na matriz do aparato de Wood e submetida à dissolução em cada meio, sob agitação de 50 rpm a 37°C. A determinação da permeabilidade dos antirretrovirais foi realizada empregando o modelo de perfusão in situ em ratos machos Wistar. Uma porção do jejuno foi isolada e a solução de perfusão (pH 6,5) contendo o fármaco foi perfundida a um fluxo de 0,2 mL.min-1 a 37°C por 120 minutos. Os resultados obtidos referentes à solubilidade da estavudina pelo método do equilíbrio foram (em mg.mL-1): 146,49 (água), 149,22 (pH 4,5), 139,43 (pH 6,8) e 130,15 (pH 7,5). A determinação da razão dose:solubilidade (D:S) em cada meio permitiu a obtenção dos seguintes resultados (em mL): 0,27 (água), 0,27 (pH 4,5), 0,29 (pH 6,8) e 0,31 (pH 7,5). Tais dados indicaram que este fármaco apresenta alta solubilidade nos meios utilizados no estudo, exceto em meio pH 1,2, onde a estavudina apresentou instabilidade demonstrada pela presença de coloração e odor alterados, inviabilizando a determinação da solubilidade nestas condições. Os ensaios de dissolução intrínseca da estavudina permitiram a determinação das taxas de dissolução intrínseca (TDI), as quais foram (em mg/min/cm²): 2,3570 (água), 2,7389 (pH 1,2), 2,7590 (pH 4,5) e 2,5947 (pH 6,8), demonstrando que este fármaco apresenta alta velocidade de dissolução nos meios utilizados. Com relação ao estudo de permeabilidade por meio do modelo de perfusão in situ, nas condições experimentais empregadas, os resultados obtidos foram (em cm.s-1): 3,96 x 10-5 (estavudina), 3,08 x 10-5 (lamivudina) e 4,17 x 10-5 (zidovudina) sugerindo que os fármacos estavudina e zidovudina apresentam alta permeabilidade. Para a lamivudina não é descartada a possibilidade de ser considerada como fármaco de alta permeabilidade, mesmo apresentando resultado ligeiramente abaixo em relação aos outros dois antirretrovirais utilizados no estudo. / Drug\'s bioavaliability is a determinant factor of clinical efficacy and it depends on the following steps: release of active ingredient from the dosage form and absorption. Thus, control of extend and rate of absorption of a drug orally administered depends on two aspects: the drug solubility in physiological fluids and permeability across biological membranes. Based on these characteristics, the Biopharmaceutical Classification System (BCS) was proposed as a tool that allows the drug\'s classification and it assists in biowaiver and in vivo bioavailability prediction. The aim of this study was to evaluate stavudine solubility and intestinal permeability of antiretroviral drugs through the in situ perfusion model. The means employed in the solubility studies and intrinsic dissolution were: purified water, buffer pH 1.2, buffer pH 4.5, buffer pH 6.8 and buffer pH 7.5. For solubility study by equilibrium method (shake-flask technique), known amounts of the drug were added in each media to reach saturation and the mixture was subjected to agitation of 150 rpm for 72 hours at 37°C. For intrinsic dissolution test, known amount of stavudine has been compressed in the matrix of Wood\'s apparatus and subjected to dissolution in each media with agitation of 50 rpm at 37°C. Permeability evaluation of antiretroviral drugs was performed using the in situ perfusion model in male Wistar rats. A portion of jejunum was isolated and perfusion solution (pH 6.5) with the drug was perfused at 0.2 mL/min at 37°C for 120 minutes. Results of stavudine solubility by equilibrium method were (in mg/mL): 146.49 (water), 149.22 (pH 4.5), 139.43 (pH 6.8) and 130.15 (pH 7.5). Dose:solubility (D:S) ratio determinations allowed to obtain the following results (in mL): 0.27 (water), 0.27 (pH 4.5), 0.29 (pH 6.8) and 0.31 (pH 7.5). These results indicate that stavudine has high solubility in the means employed in this study, except in buffer pH 1.2, where stavudine showed instability demonstrated by presence of stain and odor changed, which prevented the determination of solubility in these conditions. The intrinsic dissolution study allowed the determination of intrinsic dissolution rates (IDR), which were (in mg/min/cm²): 2.3570 (water), 2.7389 (pH 1.2), 2.7590 (pH 4.5) and 2.5947 (pH 6.8), demonstrating that this drug has a high dissolution rate in each media used. In permeability study through the in situ perfusion model, under experimental conditions adopted, the results obtained were (in cm/s): 3.96 x 10-5 (stavudine), 3.08 x 10-5 (lamivudine) and 4.17 x 10-5 (zidovudine), suggesting that stavudine and zidovudine have high permeability. It\'s possible that lamivudine might be considered high permeability drug, although its effective permeability result was slightly lower compared to effective permeability of stavudine and zidovudine.
602

Biofilmes anaeróbios: desenvolvimento e caracterização filogenética usando a hibridação in situ com sondas fluorescentes / Anaerobic biofilms: development and phylogenetic characterization using fluorescence in situ hybridization

Juliana Calábria de Araujo 11 May 2001 (has links)
Neste trabalho investigou-se o desenvolvimento de biofilmes anaeróbios em um sistema de laboratório chamado de \"Modified Robbins Device\" (MRD). O objetivo específico foi o de comparar a organização das células anaeróbias, particularmente daquelas que são comuns em lodos de esgoto, sobre superfícies hidrofílicas (vidro) e hidrofóbicas (polipropileno). A hibridação in situ com sondas fluorescentes complementares ao RNAr 16S específicas para domínio e grupos e a microscopia confocal de varredura a laser foram utilizadas para verificar a composição microbiana dos biofilmes, bem como do inóculo. Foram realizados dois tipos de experimentos, um com culturas puras de metanogênicas e outro com células oriundas de lodo granulado anaeróbio. As culturas puras de metanogênicas, Methanobacterium formicicum (DSM 1535), Methanosaeta concilii (DSM 3671) e Methanosarcina barkeri (DSM 800) foram usadas como inóculo para a formação dos biofilmes no interior do MRD durante 9 dias. Os resultados mostraram que as três espécies colonizaram ambas as superfícies após o segundo e sétimo dia de ensaio. No segundo experimento, o MRD foi inoculado com um consórcio microbiano anaeróbio e a formação do biofilme foi estudada durante 22 dias. As amostras dos biofilmes bem como aquelas retiradas do frasco-reservatório de células apresentaram composição microbiana semelhante, ambas foram dominadas por Archaeae metanogênicas hidrogenotróficas relacionadas com membros da família Methanobacteriaceae, já que foram detectadas com a sonda MB1174. Este grupo contribuiu com cerca de 44 a 90% do total de células coradas com DAPI e foi morfologicamente semelhante à Methanobacterium e Methanobrevibacter. As células detectadas com a sonda específica para membros da ordem Methanomicrobiales (MG1200) representaram cerca de 2 a 18,0% do total de células coradas com DAPI no frasco-reservatório e de 0,1 a 2,0% nas amostras dos biofilmes. Estas células foram ) morfologicamente semelhantes à Methanospirillum, também uma metanogênica hidrogenotrófica. Não foram detectadas células pertencentes à família Methanosarcinaceae, pois a hibridação com a sonda MSMX860 foi negativa. Células que hibridaram com a sonda específica para o Domínio Bacteria (EUB338) representaram cerca de 2 a 18% do total de células coradas com DAPI. Os resultados mostraram que as Archaeae metanogênicas hidrogenotróficas que foram predominantes no inóculo também dominaram os biofilmes que se desenvolveram em ambas as superfícies, vidro e polipropileno. Os dados desse trabalho sugerem que a hidrofobicidade do material suporte não influenciou o desenvolvimento e a composição microbiana dos biofilmes anaeróbios, considerando as condições específicas dos ensaios realizados. / In this study the development of anaerobic biofilms using a laboratory system called modified robbins device (MRO) were investigated. We were especially interested in comparing the organization of anaerobic cells, particularly those that are very common in domestic sewage sludge, in a hydrophilic (glass) versus a hydrophobic (polypropylene) surface. Fluorescence in situ hybridization (FISH) with domain and group speci fie probes that target intracell ular 16S rRNA and confocal laser scanning microscopy (CLSM) were used to investigate the microbial composition of both the inoculum and anaerobic biofilms. Two sets of experiments were carried, one with pure methanogenic organisms and the other with cells from a mesophilic anaerobic granular sludge. The pure methanogenic cultures, Methanobacterium formicicum (OSM 1535); Methanosaeta conci/ii (OSM 3671) and Methanosarcina barkeri (OSM 800) were used to seed the MRD to allow the development of biofilms over 9 days. The results showed that ali the three species were colonizing both surfaces after 2 and 7 days of experimental period. In the second experiment, the biofilm reactor was seeded with a microbial anaerobic consortium and biofilm forrnation was studied during 22 days. Biofilm and culture vessel samples showed nearly the same microbial composition, both were dominated by hydrogenotrophic methanogenic Archaea related to the Methanobacteriaceae as detected by the specific probe (MBI174). This group accounted for 44 to 90% of the OAPI-stained cells and morphologically resembled Methanobacterium and Methanobrevibacter. Cells detected with the Methanomicrobiales specific probe (MG 1200) accounted for 2 to 18.0% of the OAPI-stained cells in the culture vessel and 0.1 to 2.0% in the biofilm samples. These cells were morphologically similar to Methanospiriltum, also a hydrogenotrophic methanogen. No cells were detected by the Methanosarcinaceae specific probe (MSMX860). Cells which hybridized to the Bacteria specific probe (EUB338) accounted for the remaining 3 to 18% of the DAPI-stained cells. The results showed that the hydrogenotrophic methanogenic Archaea cells predominated in the inoculum and the biofilms that developed on both surfaces, glass and polypropylene. Our data suggest that the hydrophobicity of the support material did not influence the development and the microbial composition of anaerobic biofilms, considering specific conditions of the experiments.
603

Impacto da presença de atrazina na comunidade bacteriana do solo / Impact of atrazine on bacteriological soil community

Godoi, Isamara 13 February 2012 (has links)
Made available in DSpace on 2017-07-10T19:25:13Z (GMT). No. of bitstreams: 1 isamara.pdf: 1125655 bytes, checksum: 8f7b2f7606310b4ddb2713e9e4043ec0 (MD5) Previous issue date: 2012-02-13 / Chemical contamination removal in soil and water depends on microbiological community that is able to degrade these compounds. There is a great evolutionary interest on studying microorganisms that metabolize the xenobiotic ones, since they have relatively been seen as new in the last five decades. Little is known about structure variation of microbiological community of soil due do the absence and presence of s-triazine herbicides.Unlike crop dependent methods that require time to detect bacteria, molecular techniques have been developed to identify individual species in mixed populations under natural enviromments. Fluorescence in situ Hibiridization (FISH) technique overcomes some difficulties that are found out in other molecular techniques, as it does not need DNA isolation and amplification steps and allows the identification of specific genes in intact cells. Thus, this study aimed at comparing the absence/presence of atrazine effect on bacteriological community structure in soil according to the phylogenetic aspect. Target probes were used on subdivisions of alpha, beta and gamma Proteobacteria, gram-positive bacteria with high G+C content, ammonia oxidizing bacteria, nitrite oxidizing bacteria and Planctomycetes. It was also used an AtzB1 specific probe to check the atzB gene presence, which makes part of s-triazine degradation. Bacteriological amount was determined by direct counting on epifluorescence microscopy, while the corresponding values to each probe were expressed in percentages of the total count with DAPI for each sample. According to this study, positive cells were found out for all probes used in both soils, but the abundance of all groups was lower in soil contaminated with atrazine herbicide, thereby demonstrating its negative influence. Planctomycetes was the most affected group with 57% lower abundance in contaminated soil. The nitrite oxidizing bacteria was the second most affected group followed by β-Proteobacteria. It was also detected the gene atzB presence, so, it can be inferred that there are potentially degrading s-triazine bacteria in both soils. / A remoção da contaminação química no solo e água é dependente principalmente da presença de uma comunidade microbiana capaz de degradar tais compostos. A existência de microorganismos capazes de metabolizar xenobióticos é de um considerável interesse evolucionário, uma vez que estes compostos são relativamente novos no planeta nas últimas cinco décadas. Pouco se sabe sobre a variação da estrutura da comunidade microbiana do solo em função da ausência e presença dos herbicidas s-triazínicos. Diferentemente dos métodos dependentes de cultivo, que requerem tempo para a detecção de bactérias, técnicas moleculares vem sendo desenvolvidas para o reconhecimento de espécies individuais em populações mistas em ambientes naturais. A técnica de Hibridização Fluorescente in situ (FISH) supera algumas dificuldades encontradas com outras técnicas moleculares, pois dispensa as etapas de isolamento e amplificação de DNA e permite a identificação de genes específicos em células intactas. Em virtude disso, o presente trabalho teve como objetivo comparar o efeito da ausência/presença de atrazina na estrutura da comunidade bacteriana do solo no aspecto filogenético. Foram utilizadas sondas alvo para as subdivisões de Proteobactéria alfa, beta e gama, bactérias Gram-positivas com alto teor de G + C e Betaproteobactérias oxidantes de amônia, Bactérias oxidantes de Nitrito e Planctomicetos. Também foi utilizada uma sonda específica AtzB1 para verificar a presença do gene atzB que está envolvido na degradação das s-triazínas. A abundância bacteriana foi determinada através de contagem direta em microscopia de epifluorescência, e os valores correspondentes a cada sonda foram expressos em porcentagem da contagem total com DAPI para cada amostra. No presente estudo células positivas para todas as sondas utilizadas foram encontradas em ambos os solos, porém a abundância de todos os grupos foi menor no solo contaminado com o herbicida atrazina, demonstrando dessa forma a influência negativa do mesmo, sendo o grupo mais afetado o dos Planctomicetos com uma abundância 57% menor em solo contaminado. O segundo grupo mais afetado foi o das bactérias oxidantes de nitrito seguido pelo grupo das β-Proteobactérias. Foi também detectado no presente estudo a presença do gene atzB demonstrando que em ambos os solos existem bactérias potencialmente degradadoras de s-triazinas.
604

Impacto da presença de atrazina na comunidade bacteriana do solo / Impact of atrazine on bacteriological soil community

Godoi, Isamara 13 February 2012 (has links)
Made available in DSpace on 2017-05-12T14:48:37Z (GMT). No. of bitstreams: 1 isamara.pdf: 1125655 bytes, checksum: 8f7b2f7606310b4ddb2713e9e4043ec0 (MD5) Previous issue date: 2012-02-13 / Chemical contamination removal in soil and water depends on microbiological community that is able to degrade these compounds. There is a great evolutionary interest on studying microorganisms that metabolize the xenobiotic ones, since they have relatively been seen as new in the last five decades. Little is known about structure variation of microbiological community of soil due do the absence and presence of s-triazine herbicides.Unlike crop dependent methods that require time to detect bacteria, molecular techniques have been developed to identify individual species in mixed populations under natural enviromments. Fluorescence in situ Hibiridization (FISH) technique overcomes some difficulties that are found out in other molecular techniques, as it does not need DNA isolation and amplification steps and allows the identification of specific genes in intact cells. Thus, this study aimed at comparing the absence/presence of atrazine effect on bacteriological community structure in soil according to the phylogenetic aspect. Target probes were used on subdivisions of alpha, beta and gamma Proteobacteria, gram-positive bacteria with high G+C content, ammonia oxidizing bacteria, nitrite oxidizing bacteria and Planctomycetes. It was also used an AtzB1 specific probe to check the atzB gene presence, which makes part of s-triazine degradation. Bacteriological amount was determined by direct counting on epifluorescence microscopy, while the corresponding values to each probe were expressed in percentages of the total count with DAPI for each sample. According to this study, positive cells were found out for all probes used in both soils, but the abundance of all groups was lower in soil contaminated with atrazine herbicide, thereby demonstrating its negative influence. Planctomycetes was the most affected group with 57% lower abundance in contaminated soil. The nitrite oxidizing bacteria was the second most affected group followed by β-Proteobacteria. It was also detected the gene atzB presence, so, it can be inferred that there are potentially degrading s-triazine bacteria in both soils. / A remoção da contaminação química no solo e água é dependente principalmente da presença de uma comunidade microbiana capaz de degradar tais compostos. A existência de microorganismos capazes de metabolizar xenobióticos é de um considerável interesse evolucionário, uma vez que estes compostos são relativamente novos no planeta nas últimas cinco décadas. Pouco se sabe sobre a variação da estrutura da comunidade microbiana do solo em função da ausência e presença dos herbicidas s-triazínicos. Diferentemente dos métodos dependentes de cultivo, que requerem tempo para a detecção de bactérias, técnicas moleculares vem sendo desenvolvidas para o reconhecimento de espécies individuais em populações mistas em ambientes naturais. A técnica de Hibridização Fluorescente in situ (FISH) supera algumas dificuldades encontradas com outras técnicas moleculares, pois dispensa as etapas de isolamento e amplificação de DNA e permite a identificação de genes específicos em células intactas. Em virtude disso, o presente trabalho teve como objetivo comparar o efeito da ausência/presença de atrazina na estrutura da comunidade bacteriana do solo no aspecto filogenético. Foram utilizadas sondas alvo para as subdivisões de Proteobactéria alfa, beta e gama, bactérias Gram-positivas com alto teor de G + C e Betaproteobactérias oxidantes de amônia, Bactérias oxidantes de Nitrito e Planctomicetos. Também foi utilizada uma sonda específica AtzB1 para verificar a presença do gene atzB que está envolvido na degradação das s-triazínas. A abundância bacteriana foi determinada através de contagem direta em microscopia de epifluorescência, e os valores correspondentes a cada sonda foram expressos em porcentagem da contagem total com DAPI para cada amostra. No presente estudo células positivas para todas as sondas utilizadas foram encontradas em ambos os solos, porém a abundância de todos os grupos foi menor no solo contaminado com o herbicida atrazina, demonstrando dessa forma a influência negativa do mesmo, sendo o grupo mais afetado o dos Planctomicetos com uma abundância 57% menor em solo contaminado. O segundo grupo mais afetado foi o das bactérias oxidantes de nitrito seguido pelo grupo das β-Proteobactérias. Foi também detectado no presente estudo a presença do gene atzB demonstrando que em ambos os solos existem bactérias potencialmente degradadoras de s-triazinas.
605

Transfert des nitrates du bassin versant de la Tafna (Nord-Ouest de l'Algérie) vers la mer Méditerranée - approche couplant mesures, modélisation et changement d'échelle vers les grands bassins versants Nord africains / Transfer of nitrates from the Tafna watershed (North-West Algeria) to the Mediterranean sea - approach coupling measurements, modeling and changing scale to the biggest coastal rivers in North Africa

Zettam, Amin 06 May 2018 (has links)
Dans des contextes semi-arides et fortement anthropisés la caractérisation et la quantification des transferts de polluants dans les eaux de surface et vers la mer est importante à appréhender pour aider à une meilleure gestion de la ressource en eau dans un contexte de changements environnementaux. Sur le Nord-africain notamment la difficulté d’obtenir des données en quantité et qualité suffisante est difficile. La présente étude s’intéresse aux mécanismes de transfert des nitrates et des sédiments à l’échelle du bassin versant de la Tafna (7200 km2) et des plus grands fleuves de l'Afrique du Nord par une approche couplant les mesures in situ et le modèle SWAT (Soil and Water Assessment Tool). La partie in situ a permis de quantifier la quantité de nitrates apportée par les différents exutoires des sous bassins de la Tafna. Elle a aussi mis en évidence la contribution du bassin versant à l’eutrophisation de la Méditerranée tout en mesurant les quantités de nitrates acheminées vers les eaux marines. Les résultats ont mis en évidence les facteurs qui influent sur les flux et les concentrations en nitrates et notamment l’occupation du sol et les barrages ont une grande influence sur les flux de nitrates dans la Tafna. Les stations d’étude ont été classées selon un gradient d’eutrophisation, les stations amont présentant de fortes concentrations en nitrates, elles s’opposent aux stations avals. Les résultats de simulation sur la période 2003 à 2011 ont montré qu’une grande partie de l'eau de surface de la Tafna provient du ruissellement de surface (59%) et du flux latéral (40%), alors que la contribution des eaux souterraines est insignifiante (1%). La Tafna transfère une quantité annuelle moyenne de 2942 t.an-1 de sédiment vers la mer entre 2003 et 2011. SWAT a montré aussi que les cinq barrages de la Tafna stockent une grande quantité de sédiments, plus de 27 000 t.an-1 (90% des sédiments transportés par la Tafna). Le modèle reproduit aussi le flux de nitrates dans les stations de mesure entre 2003 et 2011. La Tafna transporte une quantité moyenne annuelle de 37 à 86 tN.an-1 jusqu'à la Méditerranée. Sur la base de ces résultats, l’approche de modélisation a pemis d’effectuer un changement d’échelle vers les grands bassins du nord-africain. La simulation a montré que les barrages de la Tafna stockent une quantité importante de nitrates [80 à 486 tN.an- 1], qui représente en moyenne 62% de la quantité totale de nitrates transportée annuellement par le fleuve. L’application du modèle sur les plus grands fleuves d'Afrique du Nord, Moulouya (55 860 km2), Tafna (7 200 km2), Chélif (44 694 km2) Oued el Kbir-Rhumel (8824 km2) et Medjerda (23 213 km2) a permis de représenter les flux d'eau, de sédiments et de nitrate. Les fleuves de cette région transportent une quantité de sédiments de 706 .103tan-1 vers la Mer ou le fleuve Oued Kbir-Rhumel qui contribue à la plus grande quantité (55%).Le flux de nitrates transportés vers la mer est de 5330 tN.an-1, le fleuve Moulouya qui contribue à la plus grande quantité (32%). Les barrages de cette région stockent une grande quantité de sédiments (98%) et de nitrates (39%) transportés par les fleuves vers la Méditerranée. / In semi-arid and highly anthropized area characterization and quantification of pollutant transfers in surface waters and to the sea is important to understand and to help better management of water resources, especially in North Africa, where the of obtaining data in quantity and sufficient quality is difficult. This study investigates mechanisms transfer of nitrate and sediment in the Tafna watershed (7200 km2) and at the biggest coastal rivers in North Africa with an approach, coupling in situ measurements and SWAT model (Soil and Water Assessment Tool). The in situ part made it possible to quantify the quantity of nitrates exported by the different Tafna sub-basins. It also highlighted the contribution of the watershed to eutrophication of the Mediterranean Sea by measuring the quantities of nitrates transported to marine waters. The quantities transferred are important in the high water season while they decrease in the rivers during the dry season. The results highlighted the factors that influence the nitrates flux and nitrate concentrations; the land use has a great influence on the nitrate flux in the Tafna. The study stations were classified according to the eutrophication gradient. The upstream stations with high nitrates concentration, oppose downstream stations. Modeling results showed that Tafna's surface water comes from surface runoff (59%) and lateral flow (40%), while the contribution from groundwater was insignificant (1%). Tafna has transferred an average annual amount of 2942 t.yr-1 of sediment to the sea. SWAT has also shown that dams store a large amount of sediment, over 27 000 t.yr-1 (90% of the sediments transported by Tafna). The model also reproduced the nitrates flux at the gauging stations between 2003 and 2011. The Tafna carries 37-86 tN.yr-1 to the Mediterranean Sea and Tafna dams store a large quantity of nitrates [80 and 486 tN.yr-1], which represents an average 62% of the total amount of nitrates transported annually by the river. The application of the model at largest scale in North Africa, Moulouya (55,860 km2), Tafna (7,200 km2), Chelif (44,694 km2) Oued el Kbir-Rhumel (8,824 km2) and Medjerda (23,213 km2) showed that the rivers of this region carry 706.103t.yr-1 of sediments to the Sea. The Oued Kbir-Rhumel River contributes with the greatest quantity (55%), whereas the nitrate flows transported towards the sea is 5330 tN.yr-1 and the Medjerda River contributes with the largest amount (32%). Dams in this region store a large amount of sediment (98%) and nitrate (39%) transported by rivers to the Mediterranean.
606

Avaliação das afecções odontológicas em pequenos felídeos neotropicais mantidos em cativeiro / Evaluation of dental diseases in small neotropical felids kept in captivity

Prazeres, Rodrigo Filippi 08 May 2014 (has links)
Foram estudados 50 pequenos felídeos neotropicais adultos (25 machos e 25 fêmeas) de quatro espécies distintas - 15 jaguatiricas (Leopardus pardalis), 15 gatos-do-mato-pequenos (Leopardus tigrinus), 10 gatos-maracajás (Leopardus wiedii) e 10 gatos-mouriscos (Puma yagouaroundi), provenientes de quatro coleções zoológicas do Estado de São Paulo. A finalidade foi identificar alterações odontológicas macroscópicas, divididas em quatro grupos: 1. variações, anomalias e ausências dentárias; 2. doença periodontal; 3. traumatismos; 4. lesões de reabsorção dentária. Verificou-se que tais alterações são frequentes, mesmo em animais assintomáticos, sendo a halitose a manifestação clínica aparentemente mais comum. Dentre as alterações verificadas, a doença periodontal (88,0%) foi a mais prevalente, sendo cálculo dental e gengivite os principais achados clínicos, acometendo principalmente a face vestibular dos dentes maxilares. O segundo grupo de alterações odontológicas de maior prevalência foi o de traumatismos (66,0%), principalmente em Leopardus pardalis e Puma yagouaroundi, com destaque para a abrasão dentária, e maior acometimento dos dentes caninos. Ausência de dentes foi o achado mais prevalente no grupo das variações, anomalias e ausências dentárias (54,0%), predominando ausência de incisivo superior medial direito, segundo pré-molar superior direito, canino superior esquerdo e incisivos inferiores laterais, esquerdo e direito, com maior frequência em Puma yagouaroundi. Lesões de reabsorção dentária foram pouco prevalentes (10,0%), sendo observadas principalmente em dentes pré-molares e molares mandibulares. / There were studied 50 adult small neotropical felids (25 males and 25 females) from four species - 15 Leopardus pardalis, 15 Leopardus tigrinus, 10 Leopardus wiedii and 10 Puma yagouaroundi from four zoological collections of the State of São Paulo, Brazil. The objective was to identify macroscopic dental changes, divided into four groups: 1. variations, anomalies and missing teeth; 2. periodontal disease; 3. trauma; 4. resorptive lesions. It was found that such changes are frequent, even in asymptomatic animals, and halitosis is apparently the most common clinical manifestation. Among the changes, periodontal disease (88.0%) was the most prevalent, with dental calculus and gingivitis as major clinical findings, affecting mainly the vestibular surface of the maxillary teeth. The second group of higher prevalence dental findings was trauma (66.0%), mainly observed in Leopardus pardalis and Puma yagouaroundi mainly tooth abrasion, with prevalence of canine teeth. Dental absence was the most prevalent finding in the group of variations, anomalies and missing teeth (54.0%), predominating absence of right medial incisor, second right premolar, upper left incisors and lower right and left canine teeth, with major frequency in Puma yagouaroundi. Resorptive lesions were less prevalent (10.0%), being mainly observed in premolars and mandibular molars.
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Preparação, caracterização e estudo eletroquímico de ligas Pt/M e Pt/M/M1 (M, M1 = Mo, Sn, Ru, Os e W) para eletrooxidação de etanol com aplicações em DEFC / Preparation, characterization and electrochemical studies on Pt/M/M1 (M,M1 = Mo, Sn, Ru, Os and W) catalysts for ethanol oxidation and DEFC application

Anjos, Daniela Marques dos 14 December 2007 (has links)
A eletrooxidação de etanol foi investigada sobre catalisadores bi e trimetálicos constituídos de Pt-M1 e Pt-M-M1 M = Sn, Mo, W, Ru, Os e Ir). Os eletrodos foram preparados em três diferentes configurações: eletrodos lisos (preparados em forno a arco voltaico), filmes depositados em placas de Ti (Pt-M/Ti) e nanopartículas metálicas dispersas em carbono (Pt-M-M1/C), ambos preparados pelo método Pechini. Os resultados eletroquímicos mostraram que a adição dos diferentes metais à platina aumentou a atividade catalítica dos eletrodos. Este efeito se mostrou dependente da composição do eletrodo e para os eletrodos lisos apresentou resultados mais acentuados nas composições Pt-Os e Pt-Sn-W. Os intermediários e produtos de reação da oxidação de etanol os eletrodos lisos foram determinados pelas técnicas de FTIR in situ de SPAIRS e SNIFTIRS. Os resultados sugerem que a presença dos elementos modificadores da platina aumentam a velocidade da reação de oxidação de etanol pela dessorção de intemediários com dois átomos de carbono (como CH3CHOads) a potenciais mais baixos do que a Pt levando conseqüentemente a liberação dos sítios ativos para nova adsorção de etanol. Constatou-se contudo, que a presença desses elementos não favorece a quebra da ligação C-C para formação de CO2 em quantidades apreciáveis. As composições de catalisadores Pt-M/Ti (M = Sn, Ru, Ir e Mo) preparados pelo método Pechini que apresentaram os melhores resultados em densidades de corrente foram os eletrodos de Pt-Sn/Ti. As análise por HPLC mostraram o produto majoritariamente formado foi o acetaldeído independente da composição do catalisador, mas os catalisadores Pt-Sn/Ti tiveram a maior seletividade na formação de ácido acético. Os testes em célula unitária foram realizados para os catalisadores trimetálicos Pt-Sn-W/C em diferentes composições. A presença de Sn e W aumentou significativamente o desempenho da célula com relação à Pt pura. O melhor catalisador testado (Pt-Sn-W/C (85:8:7)) apresentou OCV de 777 mV contra 345 mV da Pt a 90oC. A densidade de potência máxima alcançada para essa composição foi de 33 mW cm-2. A análise de produtos ao final de 5 horas de reação a 90oC aplicando 30 mA cm-2 de corrente mostrou que os produtos principalmente formados foram ácido acético e acetaldeído. / Ethanol oxidation on Pt-M1 e Pt/M/M1 (M = Sn, Mo, W, Ru, Os e Ir) catalysts prepared by arc melting furnace process and Pechini method was investigated. The electrochemical data showed that the addition of these elements to Pt gives a highest current densities at lower potentials. The best composition of electrodes prepared by arc melting process based on current densities values was Pt-Os and Pt-Sn-W. The intemediates and reaction products for ethanol oxidation were detected by SPAIRS and SNIFTIRS. The results sugest that adding a foreign metal to Pt leads an increase of the reaction rate for ethanol oxidation because desorption of two carbon atoms intermediates (as CH3 CHOads) at lower potentials comparing to pure Pt. The active site become then available for the new ethanol adsorption. However, the presence of these metals doesn\'t increase the selectivity to CO2 generation. Pt-M/Ti (M = Sn, Ru, Ir e Mo) catalysts were prepared by Pechini method. The products of the ethanol oxidation on these electrodes were evaluated by HPLC. The results showed that acetaldehyde was the main product obtained for all compositions. DEFCs tests were carry on with Pt-Sn-W/C ternary catalysts in different compositions. It was obtained particles size about 3.9 to 11 nm, depending on the catalyst composition. The addition of Sn and W increased significantly the DEFC performance. The best result was obtained by Pt-Sn-W/C (85:8:7) catalyst. It presents OCV about 777 mV against 345 mV to Pt at 90oC. The maximum of power density for this catalyst was 33 mW cm-2. Acetaldehyde was the major product formed when applying a fixed current of 30 mA cm-2 at 90oC.
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Rock mass mechanical behavior in deep mines : in situ monitoring and numerical modelling for improving seismic hazard assessment / Comportement mécanique des massifs rocheux dans les mines profondes : surveillance in situ et modélisation numérique pour l’amélioration de l'évaluation de l'aléa sismique

De Santis, Francesca 05 February 2019 (has links)
Afin de mieux comprendre les interactions entre les modifications des contraintes induites par l'exploitation minière et la génération d'activité sismique, une zone profonde de la mine de Garpenberg (Suède) a été instrumentée par l’Ineris avec de sondes microsismiques et de cellules géotechniques. L’analyse spatio-temporelle des événements microsismiques enregistrés entre 2015 et 2016, ainsi que leurs paramètres à la source, ont mis en évidence deux types de réponses sismiques : une locale et courte dans le temps directement induite par les tirs de production, l’autre plus persistante et distante des excavations étant principalement contrôlée par des hétérogénéités géologiques. L’analyse des données géotechniques a montrée l’occurrence de déformations asismiques, ainsi que de phénomènes de fluage induits par l’exploitation. De plus l'activité sismique décroît proportionnellement au taux de diminution des déformations mesurées. Cette dernière observation implique que le fluage peut être un autre mécanisme menant à la sismicité, s’ajoutant au changement de contrainte immédiat induit par les tirs de production. Dans la dernière partie de cette thèse, un modèle géomécanique élasto-plastique 3D a été réalisé et ses résultats ont été comparés aux données géophysiques. Cette comparaison a montré que les modèles numériques à l'échelle de la mine peuvent être des outils puissants pour étudier la sismicité induite à grande échelle. Cependant, il y a certains aspects de la sismicité induite que le modèle ne peut expliquer entièrement. Cela est le cas pour la sismicité déclenchée à distance des excavations, alors que de meilleures corrélations sont trouvées lorsque l'on considère la sismicité à proximité des zones de production. Les résultats de cette thèse ont démontré qu'une approche combinée associent les données sismiques et géotechniques à la modélisation numérique peut améliorer considérablement notre compréhension de la réponse des massifs rocheux à l'exploitation minière. La combinaison de ces méthodologies dans une approche intégrée peut réduire considérablement leurs limites explicites qui sont évidents lorsque ces instruments sont considérés séparément. / With the aim of better understanding interactions between stress modifications induced by mining and the generation of seismic activity, a deep area of Garpenberg mine (Sweden) was instrumented by Ineris with microseismic probes and geotechnical cells. Spatiotemporal analysis of recorded seismicity between 2015 and 2016, as well as seismic source parameters, have highlighted two types of seismic rock mass responses: one local and temporally short directly induced by production blasts, the other long-lasting over time and remote from excavations being mainly controlled by geological heterogeneities. Geotechnical data analysis showed the occurrence of aseismic deformations, as well as creep phenomena induced by mining exploitation. In addition, seismic activity decays proportional to the decaying rate of measured strains. This latter observation implies that creep may be another mechanism driving seismicity, in addition to the immediate stress change induced by blasting. In the last part of this thesis, a 3D elasto-plastic geomechanical model has been realized and its results have been compared with geophysical data. This comparison showed that mine-wide numerical models can be suitable for the analysis of mining induced seismicity at large-scale. However, there are some aspects of the induced seismicity that the model cannot fully explain. This is particularly true for remote seismicity occurring at a distance from excavations, while better correlations are found when considering seismicity close to production areas. Results of this thesis demonstrated that a combined approach which associates seismic and geotechnical data with numerical modelling can significantly improve our understanding of the rock mass response to mining. The combination of these methodologies in an integrated approach can significantly reduce their straightforward limitations, which appears evident when these instruments are considered separately.
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Des systèmes amorceurs hautes performances pour les photopolymérisations radicalaires, cationiques ou radicalaires contrôlées / Initiators systems high performance for radical, cationic or radical controlled photopolymerization

Telitel, Sofia 24 September 2015 (has links)
Des photoamorceurs construits sur une chimie radicalaire originale sont développés. Les photopolymères présentent des avantages écologiques (pas de COV) et économiques. Ils sont utilisés dans les adhésifs, les encres, les revêtements, l’optique… Une première étude est réalisée sur la photopolymérisation radicalaire (FRP) en présence d’organoboranes. Sous l’action de la lumière, des radicaux boryles sont formés. Ces composés convertissent des radicaux peroxyle (stables) en radicaux boryles très réactifs sous air. Ils permettent ainsi une polymérisation radicalaire en milieu aéré. Avec l’ajout de colorant, la photopolymérisation a lieu sous lumière visible.Une seconde étude est menée sur la photopolymérisation cationique (FRPCP). Des sources d’irradiation douces (lampe halogène, LED,…), peu énergivores et peu coûteuses sont employées. Des composés photosensibles ayant de fortes propriétés d’absorption dans le visible sensibilisent les sels d’iodonium. Cette décomposition permet d’amorcer la polymérisation cationique sous faible intensité lumineuse.Enfin, la polymérisation radicalaire contrôlée/vivante induite par de la lumière UV et visible est présentée. Deux modes de polymérisation contrôlée sont discutés : la NMP2 (Nitroxide Mediated PhotoPolymerization) et l’ATRP2 (Atom Transfer Radical PhotoPolymerization). En NMP2, les alcoxyamines ont la particularité de se réactiver sous irradiation lumineuse. En ATRP2, de nouveaux complexes d’iridium et de fer ayant de bonnes propriétés d’absorption dans le visible sont employés comme photocatalyseurs. Les résultats montrent un caractère contrôlé/vivant lors de la photopolymérisation du MMA. / Photoinitiators constructed on an original radical chemistry are developed. Photopolymers have ecological advantages (no VOCs) and economic. They are used in adhesives, inks, coatings, optical...A first study is carried out on the radical curing (FRP) in the presence of boron molecules. Under light irradiation, boryls radicals are formed. These compounds convert peroxyl radicals (stable) in boryls radicals highly reactive under air. They allow a radical polymerization in aerated medium. With the addition of dye, the photopolymerization is carried out under visible light.A second study was conducted on the cationic curing (FRPCP). Soft radiation sources (halogen lamp, LED, ...), energy efficient and inexpensive are used. Photosensitive compounds having high absorption properties in the visible sensitize iodonium salts. This decomposition allows initiating the cationic polymerization under low light intensity.Finally, controlled/living radical polymerization induced by UV and visible light is presented. Two controlled polymerization methods are discussed: NMP2 (Nitroxide Mediated Photopolymerization) and ATRP2 (Atom Transfer Radical Photopolymerization). In NMP2, alkoxyamines have the particularity to be reactivated under light irradiation. In ATRP2, new iridium complexes and iron having good absorption properties in the visible range are used as photocatalysts. The results show a controlled/living character during the photopolymerization of MMA.
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Développement d'un contrôle optique multicritère : application à la détermination d'indice in situ / Development of a multicriteria optical monitoring : application to the in situ refractive index determination

Stojcevski, Dragan 17 March 2016 (has links)
Les performances des filtres interférentiels répondent aujourd'hui à des spécifications de plus en plus exigeantes et permettent de repousser les limites physiques des instruments optiques dans lesquels ils sont intégrés. Au cours du processus de fabrication d'un filtre, il est évidemment primordial de maîtriser avec une très grande précision (typiquement sub-nanométrique) l'épaisseur optique des couches déposées. Ceci nécessite le recours à une mesure in situ des caractéristiques optiques de l’empilement tout au long de son dépôt.Dans le cadre de ce travail de thèse, nous avons développé un nouveau système de contrôle optique qui rend possible la mesure simultanée de la transmission d’un empilement, d’une part à une seule longueur d’onde, définie par l’utilisateur dans le domaine spectral compris entre 350 et 1000 nm (contrôle monochromatique présentant une résolution de 0,35 nm), et d’autre part sur l’ensemble de ce domaine spectral (contrôle large bande présentant une résolution de 3 nm). Ces deux mesures sont réalisées en 6 millisecondes à une cadence de 2 Hz (fréquence de rotation du porte-substrat), et ce, de manière parfaitement synchrone. En outre, grâce à la mise en place, dans le plateau porte-substrat, d’une voie de référence correspondant à une absence d’échantillon, ce dispositif de contrôle présente une très grande stabilité et une justesse meilleure que le pour mille. Enfin, une méthode numérique a été développée pour rendre possible une comparaison fiable des résultats fournis par les deux voies de mesure malgré la différence de leur résolution spectrale.Ce dispositif ouvre la voie à l’utilisation de plusieurs critères indépendants pour définir en temps réel l’instant précis où le dépôt d’une couche doit être arrêté (annulation de la dérivée de la transmission à une longueur d’onde, comparaison de cette transmission monochromatique à un niveau pré-défini, minimisation d’une fonction de mérite quantifiant l’écart entre le spectre mesuré et un spectre de référence défini par le calcul, respect d’une durée de dépôt utilisant une mesure optique in situ de la vitesse de dépôt). Il s’agit donc bien d’un contrôle multi-critère tout optique.La première application des potentialités de ce nouveau système a concerné la détermination des constantes optiques (indice de réfraction, coefficient d’extinction) d’un matériau diélectrique de haut indice, le pentoxyde de tantale. La méthode utilisée met en œuvre un enregistrement de l’évolution de la transmission spectrale de l’échantillon tout au long de la croissance de la couche (voie large bande) et un traitement, longueur d’onde par longueur d’onde, du profil temporel de cette évolution. Cette nouvelle méthode ne nécessite donc pas le choix a priori d’une loi de dépendance spectrale pour chacune de ces deux constantes optiques. Elle ouvre également la voie à une analyse de l’évolution de l’indice de réfraction d’une couche en fonction de l’épaisseur qui lui est assignée. Enfin, elle est transposable à des matériaux bas indice, comme, par exemple, la silice / The performances of complex interference filters meets today to exigent specifications and permit to enhance the physical limits of optical instruments in which they are integrated. During the manufacturing of a filter, it is obviously important to monitor with very high accuracy (typically sub-nanometric) the thickness of the deposited layers. This requires the use of an in situ measurement of the optical characteristics of the multilayer during the process.In the framework of this thesis, we have developed a new optical monitoring system which makes possible to achieve the simultaneous measurement of the transmittance of a multilayer filter, on one hand at a single wavelength defined by the user in the spectral range between 350 nm and 1000 nm (monochromatic monitoring with a resolution of 0.35 mm), and on the other hand on this whole spectral range at single shot (broadband monitoring with a resolution of 3 nm). These two measurements are made in 6 milliseconds at a rate of 2 Hz (corresponding to the rotation speed of the substrate holder), and are perfectly synchronized. In addition, the substrate holder tray is designed with a reference channel corresponding to a void position (without sample). Thanks to that configuration the monitoring system has a very high stability and accuracy better than 0.001. Finally, a numerical method has been developed to enable the comparison of the results provided by the two acquisition channels (monochromatic and broadband) taking into account the difference of their spectral resolution.This system opens the way for the use of several independent criteria to determine in real time the exact moment when the deposition of a layer must be stopped (turning point monitoring, trigger point monitoring, broadband monitoring, achievement with time monitoring using an optical in situ determination of the deposition rate). So this is indeed an all optical multi-criteria monitoring systems.This first application of this system has involved the determination of the optical constants (refractive index and extinction coefficient) of a high index dielectric material: the tantalum pentoxide. The method used is based on a recording of the evolution of the transmitted spectrum of a witness sample during the growth of the layer (broadband channel) and a processing, wavelength by wavelength, of the timing data profile of that evolution. This new method does not require any descriptive spectral dependence law for each of the two optical constants. It also paves the way for an analysis of the behavior of the refractive index of a layer in function of the thickness. Finally, it is applicable to low index materials, such as, for example, silica.

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