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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.
411

Difusão de spins nucleares em meios porosos - uma abordagem computacional da RMN / Nuclear spin diffusion in porous media - a computational approach of NMR

Lucas-Oliveira, Éverton 19 February 2015 (has links)
A Ressonância Magnética Nuclear (RMN) é uma importante técnica empregada nas principais áreas de conhecimento, tais como, Física, Química e Medicina. Importantes trabalhos da RMN aplicada ao estudo da dinâmica de moléculas em fluidos presentes em meios porosos permitiram que esta técnica ganhasse também notoriedade na indústria do petróleo. O presente projeto é fundamentado em alguns destes trabalhos seminais, reproduzindo, através de modelos físico-computacionais, os principais efeitos físicos da difusão e a consequente relaxação dos spins dos núcleos atômicos presentes nas moléculas dos fluidos imersos nos meios porosos. Os métodos teóricos utilizados para a interpretação dos parâmetros de relaxação transversal (T2) e longitudinal (T1), levam em consideração as propriedades macroscópicas da dinâmica de um ensemble de spins nucleares. Para a compreensão da difusão e relaxação nuclear em meios porosos, é de fundamental importância o emprego de métodos físico-computacionais que levam em consideração tanto a microestrutura quanto a difusão translacional dos spins nucleares através desses meios. Dentro dos modelos propostos nesta dissertação, foram utilizados conceitos básicos de mecânica estatística e de relaxação nuclear, resultando em programas envolvendo consideráveis recursos computacionais. Para a realização das simulações numéricas, foi necessária a construção da microestrutura digital dos meios porosos, usando como base do processo as imagens obtidas por microtomografia de raios-X 3D. Tendo disponível a microestrutura digital, o processo de difusão através do meio poroso e a consequente relaxação dos spins nucleares foram simulados através de modelos Random Walk, um exemplo clássico de Método de Monte Carlo. As simulações numéricas dos experimentos clássicos de RMN, empregados para a determinação de distribuições de tempos de relaxação transversal (conhecidas pela sigla CPMG), e mais avançados, para a determinação de taxas de troca entre diferentes sítios dos meios porosos (experimentos de troca ou Exchange), produziram importantes resultados para a compreensão da dinâmica de fluidos em meios porosos através de difusão translacional. / Nuclear Magnetic Resonance (NMR) is a versatile technique applied in many different areas of science such as Physics, Chemistry and Medicine. Several important NMR works applied in the study of the molecular dynamics of fluids inside porous media allowed this technique to become popular in the oil industry. This project is based on some of these seminal works. Using computational physics models, the main physical effects of diffusion and relaxation for the nuclear spins in an ensemble of molecules in a fluid permeating the porous media are reproduced. The theoretical methods used to interpret the transverse (T2) and longitudinal (T1) relaxation parameters take into consideration the macroscopic dynamical properties of an ensemble of nuclear spins. In order to comprehend the diffusion and relaxation in porous media, the use of computational physics methods that take into account the translational diffusion of the nuclear spins inside the media as well as its microstructure is essential. In the proposed models by this dissertation, basic statistical mechanics and nuclear relaxation concepts were used, resulting in programs that demand considerable computational resources. For the numerical simulations it was necessary to digitally construct the microstructure of the porous media and that was achieved with the use of X-ray 3D microtomography. On this digital microstructure, the diffusion process and the resulting relaxation of the nuclear spins were simulated with random walk models, an example of the Monte Carlo Method. The numerical simulation of classic NMR experiments, such as the one used to determine the distribution of relaxation times (known as CPMG), and more advanced ones, such as the one used to determine exchange rates between different sites (2D exchange experiments), produced fundamental results to the understanding of the fluid dynamics in porous media.
412

Espectrômetro para a transferência de polarização elétron-núcleo (efeito Overhauser) / Spectrometer for electron-nuclei polarization transfer (overhauser effect)

Biscegli, Clovis Isberto 24 June 1994 (has links)
Este trabalho apresenta os detalhes da construção de um espectrômetro para a realização de experimentos de transferência de polarização elétron-núcleo (Efeito Overhauser). São também mostrados: as implementações e modificações feitas no espectrômetro de RPE existente no Laboratório de Ressonância Magnética do DFCM, os circuitos para a construção de um equipamento de RMN para operar de forma pulsado na freqüência fixa de 14 MHz, os desenhos da cavidade de RPE construída para a banda-X (~ 9,2 GHz), os \"softwares\" modificados e desenvolvidos para aquisição de dados, tratamento e reconstrução de imagens. São apresentados os resultados do aumento do sinal de RMN e as imagens obtidas através da Tomografia de Ressonância Magnética, usando amostras menores do que 1 mm de diâmetro (volume ~10 ul), a uma concentração de 2,2 mM de TEMPOL dissolvido em água destilada. / This work describes in details the arrangements that must be accomplished for development of a spectrometer for Dynamic Nuclear Polarization - DNP (Overhauser Effect). Also, the construction project of a 14 MHz pulsed NMR spectrometer and drawings of a homemade EPR cavity for X-band (~ 9,2 GHz) are shown. The DNP probe built for the experiments and modifications done on the EPR spectrometer existing at Laboratory of Magnetic Resonance are discussed in detail. Results on the enhancement of the NMR signal due electron-proton dynamic interactions are presented. NMR imaging of very small objects, 1 mm diameter glass tube filled with 5 ~10 ul of 2,2 mM of free radicals (TEMPOL) solution, obtained through back projection reconstruction NMR tomography method, are presented
413

Vers une méthodologie de la déformulation des mélanges complexes combinant outils analytiques et chimiométriques : apllication aux détergents / Towards a deformulation methodology for complex mixtures combining analytical and chemometric tools : application to detergent products

Gaubert, Alexandra 26 November 2015 (has links)
Que ce soit à des fins de contrôle qualité ou de veille concurentielle, la déformulation (action d'identifier et de quantifier les constituants d'un produit) représente aujourd'hui un véritable challenge analytique dans de nombreux domaines industriels tels que les cosmétiques, la santé, les matériaux... Dans ce contexte, nous nous sommes intéressés aux mélanges complexes que sont les produits détergents tels que les lessives qui représentent un marché en constante croissance et en perpétuelle évolution. Dans ce secteur, en effet, les réglementations sont de plus en plus drastiques et les consommateurs plus exigeants ce qui entraine le développement de nouveaux produits plus respectueux de l'environnement et de la santé intégrant des tensioactifs bio-sourcés et des enzymes. Les lessives pouvant contenir jusqu'à 25 composés différents, nous nous sommes focalisés sur l'analyse de leurs composés majoritaires que sont les tensioactifs et les enzymes. Après avoir élaboré une échantillothèque exhaustive de ces produits, la RMN du proton et la spectrométrie Raman ont été utilisées pour identifier et quantifier les tensioactifs et la spectrométrie de masse des rapports isotopiques (IRMS) pour l'évaluation de leur origine bio-sourcée. Les résultats obtenus ont montré l'intérêt du couplage de la spectroscopie Raman avec des méthodes chimiométriques d'extraction du signal comme l'ICA et la MCR-ALS pour identifier et quantifier les tensioactifs. L'IRMS a permis d'identifier les tensioactifs d'origine bio-sourcée ainsi que le type de plantes (C3 ou C4) utilisé comme matière première pour leur synthèse. Les enzymes utilisées dans la formulation d'une lessive commerciale ont pu être identifiées et quantifiées grâce à l'association d'une méthode de précipitation des protéines avec une analyse par LC-MS/MS. Ces développements analytiques contribuent à la mise en place d'une méthodologie de la déformulation des produits détergents / Deformulation of complex mixtures requires analytical methods for compound identification and quantification. It still represents a real analytical challenge in various industrial fields, such as cosmetics, health, food, materials. In this context, we studied complex mixtures such as detergents and especially, laundry detergents, that represent a constantly growing market. Regulations becoming stricter and consumers requiring more eco-friendly products, manufacturers constantly innove detergent formulations by using bio-based surfactants or enzymes. Laundry detergents containing up to 25 compounds, we focused on the analysis of their major components, i.e. surfactants and enzymes. After developing a comprehensive sample library of such raw materials, 1H NMR and Raman spectrometry were used for surfactant identification and quantification while Isotope Ratio Mass Spectrometry (IRMS) was tested to evaluate their bio-sourced origin. Raman spectrometry combined with chemometric tools such as signal extraction methods was useful for surfactant identification and quantification. Enzymes were identified and quantified using protein precipitation before analyses by LCMS/ MS. All these analytical developments contribute to the establishment of a deformulation strategy for detergent products
414

Etude de catalyseurs nitrures et oxynitrures pour l’ammoxydation du propane / Study of catalysts based on nitrures and oxynitrures for propane ammoxidation

Bildé, Jean 12 December 2012 (has links)
L’acrylonitrile est un intermédiaire de l’industrie chimique pour la synthèse de nombreuxpolymères et revêtements. Il est produit à partir de propène qui devient de plus en plus cher et rare. Ceprojet visait à développer de nouveaux catalyseurs à base de nitrures ou d’oxynitrures permettantd’utiliser le propane moins cher et abondant, qui présente un intérêt industriel vu son potentieléconomique et sa durabilité, puisque son exploitation comme précurseur chimique permettraitd’utiliser plus efficacement les ressources naturelles. De nombreux solides ont été préparés et testéscomme catalyseurs. Certains se sont avérés instables dans les conditions de réaction comme lesoxynitrures VZrON, MoVON, et LaVON. D’autres comme MgTaVON et VZrAlON sont apparusstables mais soit faiblement actifs ou non sélectifs. L’étude s’est focalisée sur les oxynitrures VAlONet leur amélioration. Ils ont été caractérisés par de multiples techniques, telles que la DRX, XES,XANES, XPS, RMN 27Al, TPD NH3 et CO2. L’influence de paramètres tels que le rapport V/Al, lepH, la surface spécifique, le temps de contact ont été étudiés. Le catalyseur optimal possède un rapportV/Al d’environ 0,30. Les études ont permis de montrer que les sites nitrurés impliqués dansl’ammoxydation du propane sont du type OxV-NH2--AlO3 et que le degré d’oxydation moyen duvanadium en condition de catalyse est de 3,8. Une nouvelle méthode de préparation des catalyseurs aété mise au point à partir d’un complexe oxalate de vanadium et d’aluminium qui est décomposé parozonation, et nitruré en conditions réactionnelles. Ce catalyseur s’avère plus actif et sélectif que lescatalyseurs préparés par co-précipitation. / Acrylonitrile is an intermediate of the chemical industry, used for synthesis ofnumerous polymers and coating. It is produced by ammoxidation of propene, which becomes rare andexpensive. This project aimed to develop new catalysts based on nitrides and oxynitrides allowing touse abundant and cheaper propane as starting product. Propane presents an industrial interest in viewof its economical potential and durability and because its exploitation as chemical precursor wouldallow to use natural resources more efficiently. Numerous oxynitrides based catalysts have beenprepared and tested as catalysts. Some of them were shown to be unstable in reaction conditions, likeVZrON, MoVON, and LaVON, some were shown to be stable but either weakly active or notselective like MgTaVON and VZrAlON. The study has been focused on VAlON oxynitrides. Thesecatalysts have been characterized by several techniques, like XRD, XES, XANES, XPS, 27Al-NMR,NH3 and CO2-TDP and the influence of several parameters on their catalytic properties have beenstudied. The results of these studies have confirmed that these catalysts were very efficient for thereaction and shown that the optimal catalyst had a V/Al ratio around 0.30 with an average oxidationstate of vanadium in catalytic condition around 3.8. A nitridation site has been proposed correspondingto OxV-NH2--AlO3 species. Finally a new preparation method has been discovered with the synthesisof an oxalate of vanadium and aluminum complex, which is decomposed by ozonation, and nitrided inreaction conditions. This catalyst showed improved activity and selectivity compared to coprecipitatedcatalysts.
415

Rôle de l'ostéopontine et de l'ostéocalcine à l'interface organique-inorganique dans les tissus osseux / Role of Osteocalcin and Osteopontin at the Organic-Inorganic Interface in Bone

Nikel, Ondr̆ej 25 October 2013 (has links)
Avec l'âge, les propriétés mécaniques des os se détériorent, conduisant à un risque accru de fracture. Bien que les mesures de densité minérale osseuse permettent de prédire, dans une certaine mesure, ces risques, elles restent insuffisantes dans un grand nombre de cas. Une compréhension plus complète des différents facteurs permettant de définir la « qualité » d'un os est donc souhaitable. Il est connu que la résistance à la fracture de tissus osseux est affectée non seulement par la glycosylation non-enzymatique du collagène, mais aussi par des protéines non collagéneuses comme l'ostéocalcine (OC) et l'ostéopontine (OPN). Cependant, le rôle structural de ces deux protéines dans l'os est mal connu, de même que la façon dont elles contribuent aux propriétés mécaniques globales. L'objectif de cette thèse est donc de répondre à ces deux points. Un modèle synthétique a ainsi été développé pour élucider quelles sont les interactions-clés gouvernant l'interaction de l'OC et l'OPN avec la phase minérale osseuse. Par ailleurs, en utilisant des os de souris génétiquement modifiées (déficientes en OC et/ou OPN), des études RMN solide ont été menées, pour élucider le rôle de l'OC et l'OPN à l'interface organique-inorganique. Leur lien avec les propriétés mécaniques a aussi été étudié en détail, via des tests de rupture, de fatigue et de fluage. Les résultats obtenus montrent que l'OC et l'OPN ont un rôle structural important dans les tissus osseux, et qu'elles contribuent aux propriétés mécaniques par le biais de leurs interactions ioniques, au niveau des interfaces entre les fibrilles de collagène minéralisés. / The decrease in bone mechanical properties occurs with age. The associated fragility fractures present a global public health concern. The use of bone mineral density as a predictor of risk of fracture is, however, limited. A more comprehensive understanding of bone quality and its link to bone fragility is thus desirable. Besides the brittleness caused by nonenzymatic glycation of collagen, bone fracture resistance is also influenced by noncollagenous components such as osteocalcin (OC) and osteopontin (OPN). The structural role of OC and OPN in bone and how they contribute to mechanical properties is however unclear. The objective of this thesis is to elucidate these two aspects. Key interactions associated with the binding of OC and OPN to bone mineral were studied in a synthetic model. Using genetically modified animal model lacking OC and/or OPN, the role of OC and OPN in organic-inorganic interface was examined by solid state NMR, and their link to mechanical properties was studied via a series of tissue level mechanical tests, measuring fracture toughness, creep, or fatigue. Based on the results obtained, it is concluded that OC and OPN are present as structural elements in bone and contribute to tissue mechanical properties via ionic interactions at the interfaces between mineralized fibrils.
416

Understanding the effects of inhibiting human peroxiredoxin proteins for potential treatment against post-ischemic brain inflammation / Compréhension des effects de l'inhibitions des protéines peroxyrédoxines humaines pour le traitement potentiel de l'inflammation post-ischemique du cerveau

Chow, Melissa L. 08 July 2016 (has links)
Les accidents vasculaires cérébraux (AVC) sont la seconde cause d'invalidité à long terme et de mortalité dans le monde entier qui résulte d'une perte de sang au cerveau. Il y a actuellement peu de médicaments pour traiter les accidents vasculaires cérébraux. Pourtant, il y a un intérêt pour trouver un traitement, ciblant spécifiquement la cascade post-inflammatoire. Il y a une attention particulière pour inhiber les protéines peroxyrédoxines humaines (hPrx) qui sont des initiateurs clés de l'inflammation. Les protéines hPrx sont des enzymes qui dégradent les peroxydes et aussi protègent les cellules du stress oxydatif. Cette thèse est centrée sur l'étude de ligands potentiels des hPrx, dérivés du catéchol, susceptibles de devenir des agents thérapeutiques potentiels pour traiter les AVC. Premièrement, différents ligands potentiels ont été criblés par RMN et modélisation moléculaire pour savoir s'ils pouvaient se lier à différents isoformes des peroxirédoxines. Ces études ont révélé que ces dérivés du catéchol pouvaient se lier à plusieurs hPrx. Deuxièmement, la capacité des dérivés du catéchol à inhiber l'activité des hPrx a été examinée au travers de tests enzymatiques in vitro. Il a été montré que tous les dérivés du catéchol étudiés étaient capables de les inhiber. En utilisant des simulations de dynamique moléculaire, nous avons pu expliquer le mécanisme d'action moléculaire d'inhibition. En général, cette recherche fournit un aperçu des ligands qui pourrait être développés pour devenir un médicament pour aider dans le processus de rétablissement de patients atteints d'attaque cérébrale / Strokes are the second leading cause of long-term disability and death worldwide that result from a sudden loss of blood to the brain. Currently, there are limited drugs to treat patients when having a stroke. However, there is now interest focused on treatment after a stroke, specifically the post-inflammation cascade. In particular, there is attention to inhibit human peroxiredoxin proteins, which are key initiators of inflammation. Human peroxiredoxins are enzymes that degrade peroxides and also, protect the cells against oxidative stress. This thesis focuses on studying ligands, catechol derivatives, to bind and inhibit human peroxiredoxin proteins to become potential therapeutic agents for strokes. First, the ligands were screened to identify if they could bind to various human peroxiredoxin isoforms with NMR and computational modeling techniques. This study revealed the catechol derivatives could indeed bind to several human peroxiredoxins. Second, the ability for the catechol derivatives to inhibit human peroxiredoxin peroxidase activity was examined through an in vitro enzymatic assay. All the catechol derivatives were determined to inhibit several human peroxiredoxins. In utilizing molecular dynamic simulations, it assisted in explaining the in vitro inhibition molecular mechanism of action. Overall, this research provides insight of molecules that could be further developed to become possibly a drug to aid in stroke patients recovery process
417

ContribuiÃÃo ao conhecimento quÃmico de plantas do nordeste do Brasil: Aspidosperma ulei Markgr. / Contribution to the knowledge of chemical plants of northeast Brazil: Aspidosperma ulei Markgr

Zelina Estevam dos Santos Torres 30 March 2012 (has links)
FundaÃÃo de Amparo à Pesquisa do Estado do Amazonas / Aspidosperma ulei Markgr, popularmente conhecida como pitià ou piquiÃ, apresenta-se como uma Ãrvore com casca Ãspera e acinzentada. No presente trabalho foi realizado o estudo fitoquÃmico dos extratos etanÃlicos das folhas de Aspidosperma ulei, alÃm de uma reinvestigaÃÃo fitoquÃmica do caule e raiz de um espÃcime coletado na localidade Garapa, MunicÃpio de Acarape, no estado do CearÃ. Para os extratos etanÃlicos dos lenhos do caule e raiz e da casca da raiz foram realizados tratamentos por extraÃÃo Ãcido/base para obtenÃÃo das fraÃÃes alcaloÃdicas. Para as folhas e a casca do caule, alÃquotas dos extratos etanÃlicos de ambas foram submetidas a cromatografias convencionais sobre sÃlica gel e por CLAE, possibilitando o isolamento do triterpeno Ãcido ursÃlico, um derivado do inositol, o metil-chiro-inositol e dos alcaloides indÃlicos β-ioimbina, ioimbina, 3,4,5,6-tetra-desidro-β-ioimbina, 19,20-desidro-17α-ioimbina e 19(E)-hunteracina. Das fraÃÃes alcaloÃdicas dos lenhos do caule e da raiz foram obtidos por CLAE, 20(E)-17-nor-subincanadina E, relatado pela primeira vez como produto natural, alÃm do Ãcido 12-hidroxi-N-acetil-21(N)-desidro-plumerano-18-Ãico, um alcaloide indÃlico tambÃm inÃdito como produto natural. Da fraÃÃo alcaloÃdica da casca da raiz foram obtidos por CLAE a uleÃna, 20-epi-dasicarpidona, 20-epi-N-nordasicarpidona, N-desmetiluleÃna, olivacina e a δ-lactona booneÃna. O Ãcido ursÃlico e a 20(E)-17-nor-subincanadina E foram submetidos a testes de atividade citotÃxica e apresentaram resultados significativos frente a 4 linhagens de cÃlulas tumorais. A identificaÃÃo e caracterizaÃÃo dos compostos isolados foram realizadas por tÃcnicas espectroscÃpicas como IV, EM e RMN uni e bidimensional, inclusive tÃcnicas como HSQC, NOESY, COSY e HMBC, alÃm de comparaÃÃo com dados da literatura. / Aspidosperma ulei Markgr. popularly known as pitià or piquiÃ, is a tree of a rough and gray trunk bark. This work reports the phytochemical analysis of the leaves, and the re-investigation of the trunk and roots of an A. ulei specimen collected at the locality of Garapa- Acarape Country â Cearà State. The ethanol extracts of all parts were obtained. Acid/base extraction was performed with the extracts from the trunk and root heartwoods and root bark, in order to obtain the alkaloids fraction. For the leaves and trunk bark small portions of the ethanol extract were submitted to conventional chromatography over silica gel followed by semipreparative HPLC to afford the triterpene ursolic acid, an inositol derivative the methyl-chiro-inositol, and the alkaloids β-yohimbine, yohimbine, 3,4,5,6-tetradehydro-β-yohimbine, 19,20-dehydro-α-yohimbine and 19(E)-hunteracine. From the alkaloidal fractions of the trunk and the root heartwood, were obtained, by semi preparative HPLC, the alkaloids 20(E)-17-nor-subincanadine E, reported for the first time for the species and also an natural product, and the 12-hydroxy-N-acetyl-21(N)-dehydro-plumeran-18-oic acid, on unknown indole alkaloid. From the alkaloidal fraction of the root bark, after semipreparative HPLC, were obtained the indole alkaloids uleine, 20-epi-dasycarpidone, 20-epi-N-nordasycarpidone, N-noruleine, olivacine and the booneine lactone. Ursolic acid and 20(E)-17-nor-subincanadine E were assayed as citotoxic and showed significative results against four tumour cell lines. The identification and characterization of all compounds were realized by means of spectroscopic techniques such as IR, MS and uni and bidimensional NMR, including pulse sequences such as HSQC, NOESY, COSY and HMBC, after comparison to the literature data.
418

AplicaÃÃo de tÃcnicas contemporÃneas de ressonÃncia magnÃtica nuclearno estudo fitoquÃmico de Aspidosperma ulei Markgf / Application of techniques contemporaries of nuclear magnetic resonance in the fitoquÃmico investigations of Aspidosperma Ulei Markgf

Daniel Esdras de Andrade Uchoa 20 December 2006 (has links)
CoordenaÃÃo de AperfeiÃoamento de NÃvel Superior / O material vegetal (raiz e caule) de Aspidosperma ulei Markgf (Apocinaceae), popularmente conhecida como PÃtia, foi coletada na localidade de Garapa, no municÃpio de Acarape, CearÃ. Neste trabalho, alÃquotas dos extratos etanÃlicos da casca da raiz e da casca do caule de A. ulei foram submetidas a cromatografias sobre sephadex e/ou sÃlica gel, e CLAE, possibilitando o isolamento dos alcalÃides (+)-20(S)uleÃna (AU-1). (+)-20S-dasicarpidona (AU-2), (-)-16, 19-dimetil-3, 5, 14, 21-tetra-hidro-elipticina (AU-3), (-)-β-ioimbina (AU-4), (-)-20(S)-N-desmetil-uleÃna (AU-5), (+)-15(S)-18-hidroxi-20(Z)-16, 17-nor-subincanadina E (AU-7) e (+)-15(S)-20(Z)-16, 17-nor-subincanadina E (AU-8), e o derivado do inositol (-)-D-1-O-metil-myo-inositol (AU-6). Desses alcalÃides, (+)-15(S)-18-hidroxi-20(Z)-16, 17-nor-subincanadina E (AU-7) e (+)-15(S)-20(Z)-16, 17-nor-subincanadina E (AU-8) sÃo inÃditos na literatura como produtos naturais, embora o Ãltimo jà tenha sido caracterizado como intermediÃrio de sÃnteses de alcalÃides de Stryenos. A identificaÃÃo e caracterizaÃÃo dos compostos isolados foi realizada por tÃcnicas espectromÃtricas como I. V e RMN uni- e bidimensional, inclusive tÃcnicas contemporÃneas como HSQC editado, HSQC-TOCSY e 1H,X-HMBC (X = 13C ou 15N). Estudos farmacolÃgicos de uma fraÃÃo do extrato etanÃlico da casca da raiz de A. ulei, rica em alcalÃides, realizados no Departamento de Fisiologia e Farmacologia da UFC, pelo Prof. V. S. N. Rao, demonstrou o efeito prÃ-erectil dessa fraÃÃo em ratos, em trÃs casos distintos: ereÃÃo peniana, tipo-ereÃÃo e similar a ereÃÃo. InjeÃÃo intraperitonial da fraÃÃo (25 a 50 mg/Kg), possibilitou observar efeitos semelhantes ao efeito observado para a ioimbina (2 mg/Kg). Esses estudo apÃia o uso tradicional de extratos de espÃcies de Aspidosperma em deficiÃncias orgÃnicas erÃteis. / The material (root and stem) of Aspidosperma ulei Markgf (Apocinaceae), popularly known as PitiÃ, was collected in the locality of Garapa, Acarape County, CearÃ. In this work, aliquots of the ethanol extracts of the root and of the stem barks of A. ulei were submitted to chromatographic analysis in sephadex and silica gel , and CLAE, making possible the isolation of the alkaloids (+)-20(S)uleÃne (AU-1). (+)-20(S)-dasicarpidone (AU-2), (-)-16, 19-dimethyl-3, 5, 14, 21-tetra-hydro-ellipticine (AU-3), (-)-β-yohimbine (AU-4), (-)-20(S)-N-demethyl-uleine (AU-5), (+)-15(S)-18-hidroxy-20(Z)-16, 17-nor-subincanadine E (AU-7) and (+)-15(S)-20(Z)-16, 17-nor-subincanadine E (AU-8), and a inositol derivative, the (-)-D-1-O-methyl-myo-inositol (AU-6). The alkaloid, (+)-15(S)-18-hidroxy-20(Z)-16, 17-nor-subincanadine E (AU-7) and (+)-15(S)-20(Z)-16, 17-nor-subincanadine E (AU-8) are related for the first time as natural product, but the last one has been characterization as an intermediary of the Stryenosâ alkaloids synthesis. The identification and characterization of the isolated compounds was accomplished by IR and 1D and 2D NMR techniques, mainly contemporary techniques as edited HSQC, HSQC-TOCSY and 1H,X-HMBC (X = 13C or 15N). Pharmacological studies of an alkaloid rich fraction of the root bark of A. ulei, accomplished in the Departamento de Fisiologia e Farmacologia da UFC by Prof. V. S. N. Rao. Demonstrated the pro-erectile effect of that fraction in three cases: penile erection, erection-like and genital grooming in mice. Intraperitoneal injection of the fraction (25 to 50 mg/Kg), shown all three different responses similar to yohimbine (2 mg/Kg). This study further supports the traditional use of extracts from Aspidosperma species in erectile dysfunctions.
419

Segmentação semiautomática de conjuntos completos de imagens do ventrículo esquerdo / Semiautomatic segmentation of left ventricle in full sets of cardiac images

Rafael Siqueira Torres 05 April 2017 (has links)
A área médica tem se beneficiado das ferramentas construídas pela Computação e, ao mesmo tempo, tem impulsionado o desenvolvimento de novas técnicas em diversas especialidades da Computação. Dentre estas técnicas a segmentação tem como objetivo separar em uma imagem objetos de interesse, podendo chamar a atenção do profissional de saúde para áreas de relevância ao diagnóstico. Além disso, os resultados da segmentação podem ser utilizados para a reconstrução de modelos tridimensionais, que podem ter características extraídas que auxiliem o médico em tomadas de decisão. No entanto, a segmentação de imagens médicas ainda é um desafio, por ser extremamente dependente da aplicação e das estruturas de interesse presentes na imagem. Esta dissertação apresenta uma técnica de segmentação semiautomática do endocárdio do ventrículo esquerdo em conjuntos de imagens cardíacas de Ressonância Magnética Nuclear. A principal contribuição é a segmentação considerando todas as imagens provenientes de um exame, por meio da propagação dos resultados obtidos em imagens anteriormente processadas. Os resultados da segmentação são avaliados usando-se métricas objetivas como overlap, entre outras, comparando com imagens fornecidas por especialistas na área de Cardiologia / The medical field has been benefited from the tools built by Computing and has promote the development of new techniques in diverse Computer specialties. Among these techniques, the segmentation aims to divide an image into interest objects, leading the attention of the specialist to areas that are relevant in diagnosys. In addition, segmentation results can be used for the reconstruction of three-dimensional models, which may have extracted features that assist the physician in decision making. However, the segmentation of medical images is still a challenge because it is extremely dependent on the application and structures of interest present in the image. This dissertation presents a semiautomatic segmentation technique of the left ventricular endocardium in sets of cardiac images of Nuclear Magnetic Resonance. The main contribution is the segmentation considering all the images coming from an examination, through the propagation of the results obtained in previously processed images. Segmentation results are evaluated using objective metrics such as overlap, among others, compared to images provided by specialists in the Cardiology field
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Caracteriza??o de m?is brasileiros: f?sico-qu?mica, perfil de subst?ncias polares, atividade antioxidante e quimiometria / Characterization of brazilian honeys: physico-chemical, polar substances profile, antioxidant activity and chemometrics

SALGUEIRO, Fernanda Barbosa 09 March 2012 (has links)
CAPES / Honey is generally known for its therapeutic value and the determination of its main floral source allows the certification to the consumer the properties related to its origin. Thus, the aim of this work was to evaluate the quality and characterize eleven honeys from Apis mellifera from the state of Rio de Janeiro according to physico-chemical parameters, to phenolics profile, to the antioxidant activity and also through the use of chemonetric analysis applied to 1H NMR data and HPLC-DAD. Two samples of assa peixe, six samples of cambara and three samples of morr?o-de-candeia honeys from diferente regions of Rio de Janeiro were analyzed. The physico-chemical parameters determined were: HMF content and color through a spectrophotometric method, free acidity and pH. The content of free amminoacids was also determined through the c?dmium-ninhydrine together with total proteins via the Bradford method. The antioxidant ability of honeys and their extracts was qualitatively determined through the total phenolics content using the Folin-Denis method. Total flavonoids were determined by the complexation method with aluminium chloride. The quantitative antioxidant activity of honeys was determined by the trapping of the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical, by trapping of the ABTS.+ radical and also by the iron reduction method (FRAP). The identification and quantitation of polyphenols in the extracts were done by HPLC-PDA. The use of multivariate analysis for the 1H NMR data and HPLC enabled the distinction of the honeys analyzed in this work. Thus, the use of 1H NMR and HPLC data combined with multivariate analysis may be employed as a new strategy for the fast and non-destructive typification of Brazilian honeys. / No mercado, m?is s?o conhecidos pelo seu poder terap?utico e a designa??o de sua principal fonte floral permite atestar ao consumidor as propriedades de sua origem. Assim, o objetivo deste trabalho foi avaliar a qualidade e caracterizar onze m?is de Apis mellifera provenientes do Estado do Rio de Janeiro, por meio de par?metros f?sico-qu?micos, do perfil de subst?ncias fen?licas, de seus potenciais antioxidantes, al?m de usar m?todos quimiom?tricos aplicados aos dados de RMN de 1H e CLAE-DAD. Para tanto, utilizou-se duas amostras de mel de assa peixe, seis de cambar? e tr?s de morr?o de candeia de diferentes munic?pios do Rio de Janeiro. Os par?metros f?sico-qu?micos avaliados foram: teor de HMF e a cor utilizando m?todo espectrofotom?trico, acidez livre e pH. Al?m dessas determina??es, o conte?do de amino?cidos livre foi avaliado pelo m?todo de c?dmio-ninidrina, e prote?nas totais pelo m?todo de Bradford. A capacidade antioxidante dos m?is e de seus extratos foi avaliada qualitativamente atrav?s do conte?do de fen?licos total pelo m?todo de Folin-Denis, e de flavon?ides total pelo m?todo de complexa??o com cloreto de alum?nio. A quantifica??o do potencial antioxidante foi realizada pela captura do radical 2,2-difenil-1-picril-hidrazil (DPPH), captura do radical livre ABTS.+, al?m do m?todo de redu??o do ?on f?rrico (FRAP). A identifica??o e quantifica??o das subst?ncias polifen?licas dos extratos foi feita por cromatografia l?quida de alta efici?ncia com detector de arranjo de diodos (CLAE-DAD). A aplica??o da an?lise multivariada aos dados de RMN de H e de CLAE-DAD distinguiu os m?is de assa peixe, cambar? e morr?o de candeia produzidos no Estado do Rio de Janeiro. Assim, o uso de RMN de 1H e CLAE-DAD combinado com a quimiometria pode ser uma nova estrat?gia para tipifica??o de m?is brasileiros de forma r?pida e n?o destrutiva.

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