Plantas da família Guttiferae apresentam diversas atividades biológicas sendo Hypericum o gênero mais importante devido às atividades antidepressiva, antibacteriana e antiviral de algumas espécies. Hypericum connatum, utilizado no sul do Brasil para o tratamento de feridas de boca, demonstrou atividade contra o lentivírus, responsável pela imunodeficiência felina. Objetivo: isolar e identificar as substâncias majoritárias de H. connatum e testar a atividade de extratos obtidos das partes aéreas e raízes e das substâncias isoladas frente a duas cepas do herpesvírus simples tipo 1 (HSV-1). Método: foram obtidos frações nhexano, diclorometano e metanol e extratos bruto, aquosos a diferentes temperaturas e hidro-etanólico das partes aéreas e raízes. As frações n-hexano e metanólica das partes aéreas foram submetidas à coluna cromatográfica para o isolamento de substâncias. Os extratos e substâncias isoladas foram testados frente ao HSV-1, cepas KOS e ATCC-VR733. Determinou-se a concentração máxima não tóxica (CMNT) à célula e a concentração que provoca alteração morfológica em 50% das células (CC50) pela técnica da alteração morfológica celular, utilizando-se células VERO, linhagem ATCC CCL-81. A avaliação da atividade antiviral foi realizada em placas de microtitulação e medida pela inibição do efeito citopático (ECP) provocado pelo vírus. Resultados e Conclusões: da fração n-hexano foi isolado hiperbrasilol B, da fração metanólica foram isolados amentoflavona, hiperosídeo e guaijaveriana, além de um flavonol de estrutura ainda não definida (HCN3). A fração n-hexano e o extrato bruto das raízes inibiram o ECP das cepas KOS e ATCC-VR733. Os demais extratos testados não apresentaram atividade antiviral. Dentre as substâncias analisadas, hiperbrasilol B, amentoflavona e HCN3 foram ativos frente às duas cepas. Os flavonóides hiperosídeo e guaijaverina não apresentaram atividade anti-HSV-1. / Plants from Guttiferae family present many biological activities being Hypericum the most important genus due to the antidepressive, antiinflamatory and antimicrobial activities of some species. Hypericum connatum, used in south of Brazil for the treatment of mouth wounds, demonstrated activity against the feline immunodeficiency virus. Purpose: to isolate and identify the major compounds from H. connatum and to test extracts and compounds obtained from the roots and aerial parts against two strains of the herpes simplex virus type 1. Method: nhexane, dichloromethane and methanol fractions and aqueous and hydroethanolic from the aerial parts and roots were obtained. The n-hexane and methanolic fractions from the aerial parts were submitted to column chromatography. All extracts and isolated compounds were tested against the herpes simplex virus type 1, strains KOS and ATCC-VR733. The determination of The maximum non-toxic concentrations (CMNT) and the concentration that causes morphologic alterations in 50% of the cells (CC50) was carried out by the technique of cellular morphologic alterations, using VERO cells, strain ATCC CCL-81. The assay was performed in 96-well plates and the antiviral activity was evaluated by the inibition of the measured by the viral cytopathogenic effect assay (ECP). Results and Conclusions: hyperbrasilol B was isolated from the n-hexane fraction; amentoflavone, hyperoside, guaijaverin, and a flavonol not yet identified (HCN3) were isolated from methanolic fraction. The n-hexane fraction and the crude methanolic extracts were active against both strains tested. The other extracts tested did not display antiviral activity. Among the isolated compounds, hyperbrasilol B, amentoflavone and HCN3 were active against both strains. Hyperoside and guaijaverin were not active against HSV-1.

Dans nos travaux, nous nous intéressons à la commande des convertisseurs statiques à grand nombre d'interrupteurs. Le développement des topologies multi-niveaux multi-bras a ouvert l'accès aux domaines de la forte puissance et de la haute qualité harmonique. Outre cette montée en puissance, la commande spéciale de ces dispositifs permet de conférer au convertisseur des fonctionnalités avancées de plus en plus nécessaires, comme la possibilité de filtrage actif des harmoniques, la tolérance aux pannes, la gestion du réactif, les liaisons HVDC, etc. Toutefois, un plus grand nombre d'interrupteurs au sein d'une même structure de conversion se traduit par une forte croissance du nombre de variables de commande, des degrés de liberté et par une explosion combinatoire du nombre de configurations possibles. La synthèse de lois de commande suivant les approches traditionnellement conçues pour les topologies classiques, comme les méthodes de modulation vectorielle fondées sur la représentation géométrique du convertisseur, en devient rapidement fastidieuse pour les nouvelles topologies plus complexes. De plus, les interrupteurs présents en surnombre apportent des redondances fortes qui ne sont pas nécessairement exploitées, ou du moins arbitrairement. Nous proposons une nouvelle approche de commande qui se veut moins dépendante du nombre d'interrupteurs, et qui s'affranchit des limitations induites par les méthodes de modulation géométrique. Notre approche consiste dans un premier temps à formuler de manière algébrique des problèmes de commande qui sont généralement sous-déterminés, témoignant de la présence de redondances ou degrés de liberté, et contraints, car tenant compte des limitations propres aux rapports cycliques. De manière intéressante, ces problèmes offrent une similarité avec les problèmes dits d'allocation de commande rencontrés en aéronautique, en marine ou en robotique. Dans un second temps, dans le but de fournir à chaque période de découpage une solution de commande unique et optimisée, nous concevons de nouvelles méthodes d'allocation pour les convertisseurs statiques fondées sur l'optimisation numérique en ligne à partir de techniques d'optimisation linéaire. En conséquence, les rapports cycliques sont automatiquement optimisés pour satisfaire aux références de tension tout en respectant les saturations et en exploitant les redondances disponibles selon l'état actuel du convertisseur. Nous mettons en lumière les propriétés naturellement offertes par nos méthodes. Notamment, toutes nos solutions de modulation étendent de manière maximale la zone de linéarité du convertisseur. Nous proposons des méthodes d'allocation pour la commande en tension ou en courant de topologies variées : l'onduleur quatre bras deux niveaux, l'onduleur multicellulaire à condensateurs flottants, l'onduleur modulaire multi-niveaux. Concernant les convertisseurs multicellulaires, nos méthodes d'allocation utilisent automatiquement les degrés de liberté disponible pour fournir un équilibrage actif très rapide des tensions de condensateurs flottants. Aussi, grâce à la formulation algébrique des contraintes de commande, nos algorithmes peuvent prendre en compte un défaut sur un interrupteur pour conférer au convertisseur une propriété de tolérance aux fautes du point de vue de la commande. / In our works, we are interested in control of high-switch-count power converters. The development of multileg, multilevel converters has opened the access to high power and high harmonic quality. The special control of these devices brings to the converter advanced abilities that are more and more requested nowadays, like active harmonic filtering, fault tolerance, active and reactive power transfer, High Voltage Direct Current (HVDC) links, etc. However, a higher number of switches in a conversion structure leads to a higher number of control variables, as well as more redundancies and a combinatorial explosion of the number of possible configurations. The development of control laws resulting from approaches traditionally designed for classical topologies, as for space vector modulation methods, becomes harder for new, much complex topologies. Moreover, the too many available switches bring strong control redundancies that are not necessarily exploited, at least arbitrarily. We propose a new control approach that is expected to be less dependent on the number of switches, and that does not suffer from limitations proper to geometrical modulation methods. Firstly, our approach consists in the algebraic formulation of control problems that are generally under-determined, highlighting the presence of redundancies and degrees of freedom, and constrained, because control limitations are taken into account. Interestingly, a connection can be highlighted to the so-called control allocation problem in flight control, robotics, or marine applications. Secondly, in order to compute a unique and optimized control solution at each switching period, we develop new control allocation methods for power converters based on on-line numerical optimization using linear programming techniques. Consequently, duty cycles are automatically optimized to satisfy voltage references while respecting saturations and exploiting available redundancies depending on the state of the converter. We highlight the properties naturally offered by our methods. In particular, all modulation solutions yield a maximized extension of the linearity range of the converter. We propose control allocation methods for the voltage or current control of many topologies: the four-leg two-level inverter, the multicellular flying capacitor inverter, the modular multilevel inverter.

Plantas da família Guttiferae apresentam diversas atividades biológicas sendo Hypericum o gênero mais importante devido às atividades antidepressiva, antibacteriana e antiviral de algumas espécies. Hypericum connatum, utilizado no sul do Brasil para o tratamento de feridas de boca, demonstrou atividade contra o lentivírus, responsável pela imunodeficiência felina. Objetivo: isolar e identificar as substâncias majoritárias de H. connatum e testar a atividade de extratos obtidos das partes aéreas e raízes e das substâncias isoladas frente a duas cepas do herpesvírus simples tipo 1 (HSV-1). Método: foram obtidos frações nhexano, diclorometano e metanol e extratos bruto, aquosos a diferentes temperaturas e hidro-etanólico das partes aéreas e raízes. As frações n-hexano e metanólica das partes aéreas foram submetidas à coluna cromatográfica para o isolamento de substâncias. Os extratos e substâncias isoladas foram testados frente ao HSV-1, cepas KOS e ATCC-VR733. Determinou-se a concentração máxima não tóxica (CMNT) à célula e a concentração que provoca alteração morfológica em 50% das células (CC50) pela técnica da alteração morfológica celular, utilizando-se células VERO, linhagem ATCC CCL-81. A avaliação da atividade antiviral foi realizada em placas de microtitulação e medida pela inibição do efeito citopático (ECP) provocado pelo vírus. Resultados e Conclusões: da fração n-hexano foi isolado hiperbrasilol B, da fração metanólica foram isolados amentoflavona, hiperosídeo e guaijaveriana, além de um flavonol de estrutura ainda não definida (HCN3). A fração n-hexano e o extrato bruto das raízes inibiram o ECP das cepas KOS e ATCC-VR733. Os demais extratos testados não apresentaram atividade antiviral. Dentre as substâncias analisadas, hiperbrasilol B, amentoflavona e HCN3 foram ativos frente às duas cepas. Os flavonóides hiperosídeo e guaijaverina não apresentaram atividade anti-HSV-1. / Plants from Guttiferae family present many biological activities being Hypericum the most important genus due to the antidepressive, antiinflamatory and antimicrobial activities of some species. Hypericum connatum, used in south of Brazil for the treatment of mouth wounds, demonstrated activity against the feline immunodeficiency virus. Purpose: to isolate and identify the major compounds from H. connatum and to test extracts and compounds obtained from the roots and aerial parts against two strains of the herpes simplex virus type 1. Method: nhexane, dichloromethane and methanol fractions and aqueous and hydroethanolic from the aerial parts and roots were obtained. The n-hexane and methanolic fractions from the aerial parts were submitted to column chromatography. All extracts and isolated compounds were tested against the herpes simplex virus type 1, strains KOS and ATCC-VR733. The determination of The maximum non-toxic concentrations (CMNT) and the concentration that causes morphologic alterations in 50% of the cells (CC50) was carried out by the technique of cellular morphologic alterations, using VERO cells, strain ATCC CCL-81. The assay was performed in 96-well plates and the antiviral activity was evaluated by the inibition of the measured by the viral cytopathogenic effect assay (ECP). Results and Conclusions: hyperbrasilol B was isolated from the n-hexane fraction; amentoflavone, hyperoside, guaijaverin, and a flavonol not yet identified (HCN3) were isolated from methanolic fraction. The n-hexane fraction and the crude methanolic extracts were active against both strains tested. The other extracts tested did not display antiviral activity. Among the isolated compounds, hyperbrasilol B, amentoflavone and HCN3 were active against both strains. Hyperoside and guaijaverin were not active against HSV-1.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Este trabalho teve como objetivos caracterizar fÃsico-quÃmica e estruturalmente polissacarÃdeos obtidos de folhas de Aloe barbadensis e avaliar suas atividades antiviral, anti-hemorrÃgica e prÃ-coagulante e possÃveis sinais de toxicidade. Foi realizada extraÃÃo aquosa de polissacarÃdeos totais (PT) de A. barbadensis, seguido de precipitaÃÃo por etanol e remoÃÃo dos contaminantes proteicos com TCA. A cromatografia em DEAE-celulose foi eficiente no fracionamento dos PT, onde foram obtidas as fraÃÃes PI e PII. A caracterizaÃÃo fÃsico-quÃmica mostrou que a fraÃÃo PI à composta por manose (78,4%), glucose (7,3%), galactose (2,1%), fucose (2,8%) e Ãcidos urÃnicos (10,0%), e isenta de grupos Ãster sulfato. Enquanto, a fraÃÃo PII à constituÃda por manose (39,2%), glucose (22,2%), galactose (26,3%), arabinose (3,8%), xilose (1,1%), Ãcidos urÃnicos (8,0%) e grupos Ãster sulfato (12,0%). Na revelaÃÃo das bandas polissacarÃdicas da fraÃÃo PII, obtidas por PAGE e gel de agarose corados com stainsall foi constatado a presenÃa de duas bandas que apresentaram diferentes coloraÃÃes, roxa e ciana, correspondentes a presenÃa de grupos sulfato e carboxilados, respectivamente. Na anÃlise estrutural das fraÃÃes PI e PII, por espectroscopia no IR, foi demonstrado que a fraÃÃo PI apresenta unidades monossacarÃdicas de Ã-manose O-acetiladas (812,2 e 960 onda.cm-1) e Ãcidos urÃnicos neutros (1738 onda.cm-1) em sua estrutura. Diferentemente, a fraÃÃo PII, mostrou-se ser constituÃda por unidades monossacarÃdicas de manose (1014,7 onda.cm-1), galactose (1078,2 onda.cm-1), Ãcidos urÃnicos carregados negativamente (1635 onda.cm-1) e Ãster sulfato (1329,5 e 1260,9 onda.cm-1). Na avaliaÃÃo estrutural da fraÃÃo PII por RMN foi comprovado à presenÃa do grupo Ãster sulfato. Em relaÃÃo Ãs atividades biolÃgicas, o teste de citotoxicidade mostrou que os PT e as fraÃÃes PI e PII nÃo apresentaram toxicidade para a maioria das cÃlulas testadas e nÃo foram eficientes na inibiÃÃo de vÃrus nÃo envelopados Ad-19 e Ad-41. No entanto, os PT e a fraÃÃo PI foram capazes de inibir a infecÃÃo causada por HSV-1 e HSV-2. Em ensaios com metapneumovÃrus (HMPV), a fraÃÃo PII apresentou atividade antiviral superior à ribavirina. Embora os PT e as fraÃÃes PI e PII nÃo terem apresentado atividade contra dengue vÃrus sorotipo 1 (DENV-1), os PT puderam inibir a hemorragia em ratos, diminuindo o tempo de sangramento e o tempo de protrombina. Os PT nÃo apresentaram toxicidade em camundongos, mas aumentaram o tamanho do baÃo e o nÃmero de plaquetas sanguÃneas. Pode ser concluÃdo que extratos foliares de A. barbadensis podem apresentar polissacarÃdeos neutros ou carregados negativamente por grupos carboxilados/sulfatados. Em adiÃÃo, alÃm de apresentar atividade inibitÃria contra os vÃrus HSV-1, HSV-2 e HMPV, podem tambÃm apresentar efeito anti-hemorrÃgico e prÃcoagulante, propriedades essas, importantes, visto que a complicaÃÃo de muitas viroses leva a quadros hemorrÃgicos. AlÃm disso, os PT de A. barbadensis nÃo apresentaram toxicidade expressiva, podendo ser utilizada como agente terapÃutico seguro e eficaz. / The aim of this study was to investigate the physicochemical and structural parameters of polysaccharides obtained from Aloe barbadensis leaves and to evaluate the antiviral and cytotoxic activities and procoagulant, anti-bleeding effects. In addition, toxicological analysis was carried out. The pulp was submitted to aqueous extraction (70 ÂC) and the total polysaccharides (PT) obtained by ethanol precipitation, TCA was used to remove the protein contamination. The fractionation of PT with DEAE-celulose resulted in two fractions (PI and PII). The physicochemical characterization showed that PI fraction presents mannose (78,4%), glucose (7,3%), galactose (2,1%), fucose (2,8%) and uronic acid (10,0%). Sulfate esters were not detected in PI fraction. On the other hand, PII fraction presents the monosaccharides mannose (39,2%), glucose (22,2%), galactose (26,3%), arabinose (3,8%), xylose (1,1%), uronic acids (8,0%) and sulfate esters groups (12,0%). The polysaccharidics of PII obtained by PAGE and agarose gel electrophoresis were revealed with toluidine blue and stainsall dye showing the presence of two different bands, one purple (indicative of sulfate) and another cyan (indicative of carboxilated groups). Structural analysis of PI and PII fractions by IR spectroscopy demonstrated that PI fraction is composed of residues of Ã-mannose O-acetylated (812.2 and 960 cm-1) and uronic acids (1738 cm-1). In contrast, the PII fraction is composed of mannose (1014.7 cm-1), galactose (1078.2 cm-1), negatively charged uronic acids (1635 cm-1) and sulfate ester (1329.5 and 1260.9 cm-1). These results corroborate with NMR analyses that suggest the presence of sulfate groups in PII structure. The cytotoxicity evaluation showed that PT and the fractions PI and PII did not show toxicity against most of tested cells and the same fractions were not effective against non-enveloped virus (Ad 19 and Ad 41) inhibition. However, the PT and PI fraction were able to inhibit the infection caused by HSV-1 and HSV-2. In addition, PII fraction presents antiviral activity against metapneumovirus. Although the PT and the fractions PI and PII did not show activity against dengue virus serotype 1 (DENV-1), PT could inhibit the bleeding effects in rats, reducing the bleeding and prothrombin time. The PT showed no toxicity in mice, but increased spleen size and number of blood platelets. In conclusion, A. barbadensis leaves contain neutral or negatively charged carboxylated/sulfated polysaccharides. In addition, besides having inhibitory activity against HSV-1, HSV-2 and HMPV, they can also anti-bleeding and procoagulant effect. Moreover, the PT of A. barbadensis showed no significant toxicity and can be used as a safe and effective therapeutic agent.

O presente trabalho desenvolve uma extensão do problema de corte de estoque unidimensional no caso em que a demanda pelos vários tipos de itens não é exatamente conhecida. Para considerar a aleatoriedade, foi proposto um modelo de programação estocástica de dois estágios com recurso. As varáveis de primeiro estágio são os números de barras cortadas por padrão de corte, e as variáveis de segundo estágio, os números de itens produzidos em escassez e em escassez. O objetivo do modelo é minimizar o custo total esperado. Para resolver a relaxação linear do modelo, foram propostos um método exato baseado no método Simplex com geração de colunas e uma estratégia heurística, que considera o valor esperado da demanda na resolução do problema de corte de estoque. As duas estratégias foram comparadas, assim como a possibilidade de resolver o problema de corte ignorando as incertezas. Finalmente, observou-se que é mais interessante determinar o valor ótimo do modelo recurso quando o problema sofre mais influência da aleatoriedade / This paper presents an integer linear optimization model of large scale for the one-dimensional cutting stock problem in the case which a demand is considered a random variable. To take this randomness into account, the problem was formulated as a two-stage stochastic linear program with recourse. The first stage decision variables are given by the number of bars that has to be cut according to each pattern, and the second stage decision variables by the number of holding items or backordering items production. The model objective is minimizes the total expected cost. We propose two methods to solve the model linear relaxation, one of them it is a Simplex-based method with column generation. The second method is a heuristic strategy that adopted the expected value of demand. We compare both strategies and the possibly of ignoring uncertainties on model. Finally, we observe that is much more interesting to determine the optimal recourse model solution when we have problems that are more afected by randomness

Plantas da família Guttiferae apresentam diversas atividades biológicas sendo Hypericum o gênero mais importante devido às atividades antidepressiva, antibacteriana e antiviral de algumas espécies. Hypericum connatum, utilizado no sul do Brasil para o tratamento de feridas de boca, demonstrou atividade contra o lentivírus, responsável pela imunodeficiência felina. Objetivo: isolar e identificar as substâncias majoritárias de H. connatum e testar a atividade de extratos obtidos das partes aéreas e raízes e das substâncias isoladas frente a duas cepas do herpesvírus simples tipo 1 (HSV-1). Método: foram obtidos frações nhexano, diclorometano e metanol e extratos bruto, aquosos a diferentes temperaturas e hidro-etanólico das partes aéreas e raízes. As frações n-hexano e metanólica das partes aéreas foram submetidas à coluna cromatográfica para o isolamento de substâncias. Os extratos e substâncias isoladas foram testados frente ao HSV-1, cepas KOS e ATCC-VR733. Determinou-se a concentração máxima não tóxica (CMNT) à célula e a concentração que provoca alteração morfológica em 50% das células (CC50) pela técnica da alteração morfológica celular, utilizando-se células VERO, linhagem ATCC CCL-81. A avaliação da atividade antiviral foi realizada em placas de microtitulação e medida pela inibição do efeito citopático (ECP) provocado pelo vírus. Resultados e Conclusões: da fração n-hexano foi isolado hiperbrasilol B, da fração metanólica foram isolados amentoflavona, hiperosídeo e guaijaveriana, além de um flavonol de estrutura ainda não definida (HCN3). A fração n-hexano e o extrato bruto das raízes inibiram o ECP das cepas KOS e ATCC-VR733. Os demais extratos testados não apresentaram atividade antiviral. Dentre as substâncias analisadas, hiperbrasilol B, amentoflavona e HCN3 foram ativos frente às duas cepas. Os flavonóides hiperosídeo e guaijaverina não apresentaram atividade anti-HSV-1. / Plants from Guttiferae family present many biological activities being Hypericum the most important genus due to the antidepressive, antiinflamatory and antimicrobial activities of some species. Hypericum connatum, used in south of Brazil for the treatment of mouth wounds, demonstrated activity against the feline immunodeficiency virus. Purpose: to isolate and identify the major compounds from H. connatum and to test extracts and compounds obtained from the roots and aerial parts against two strains of the herpes simplex virus type 1. Method: nhexane, dichloromethane and methanol fractions and aqueous and hydroethanolic from the aerial parts and roots were obtained. The n-hexane and methanolic fractions from the aerial parts were submitted to column chromatography. All extracts and isolated compounds were tested against the herpes simplex virus type 1, strains KOS and ATCC-VR733. The determination of The maximum non-toxic concentrations (CMNT) and the concentration that causes morphologic alterations in 50% of the cells (CC50) was carried out by the technique of cellular morphologic alterations, using VERO cells, strain ATCC CCL-81. The assay was performed in 96-well plates and the antiviral activity was evaluated by the inibition of the measured by the viral cytopathogenic effect assay (ECP). Results and Conclusions: hyperbrasilol B was isolated from the n-hexane fraction; amentoflavone, hyperoside, guaijaverin, and a flavonol not yet identified (HCN3) were isolated from methanolic fraction. The n-hexane fraction and the crude methanolic extracts were active against both strains tested. The other extracts tested did not display antiviral activity. Among the isolated compounds, hyperbrasilol B, amentoflavone and HCN3 were active against both strains. Hyperoside and guaijaverin were not active against HSV-1.

Orientador: Luziane Ferreira de Mendonça / Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Instituto de Matemática, Estatística e Computação Científica / Made available in DSpace on 2018-08-17T11:31:02Z (GMT). No. of bitstreams: 1 Soares_VanessadeCarvalhoAlves_M.pdf: 1540180 bytes, checksum: 198ad552da53ca9cbe2fd6bf7fc77c17 (MD5) Previous issue date: 2011 / Resumo: Neste trabalho, propomos a determinação de uma carteira de investimento ótima via um método sem derivada. Para isso, utilizamos o modelo de média-variância proposto por Harry M. Markowitz. no qual o problema é formulado de modo a se minimizar o risco do portfolio para um dado nível de retorno esperado, ou maximizar o nível de retorno fixado do portfolio associado a um dado nível de risco e determinar todas as carteiras ótimas, no sentido risco e retorno, formando a Fronteira Eficiente. Nosso algoritmo é baseado no Método Nelder-Mead, destinado à resolução de problemas de programação não linear irrestritos. Assim, adequamos a formulação do portfolio, que depende de restrições, para a utilização do mesmo. / Abstract: In this work we perform a portfolio optimization by using a derivative-free method. For this, we use the Mean-Variance Analysis proposed by Harry M. Markowitz, in which the problem is formulated as one of minimizing portfolio risk subject to a targeted expected portfolio return. Or, for a particular level of risk, we can find a combination of assets that is going to give the highest expected return and determine all the optimal portfolios, towards risk and return, forming the Efficient Frontier. Our algorithm is based on Nelder-Mead method, for solving problems of unconstrained nonlinear programming. Therefore, the formulation of the portfolio, subject to constraints, was adapted for its use. / Mestrado / Mestre em Matemática

Dans cette thèse, nous nous intéressons à la caractérisation et la reconnaissance d'activités humaines dans des vidéos. L'intérêt grandissant en vision par ordinateur pour cette thématique est motivé par une grande variété d'applications telles que l'indexation automatique de vidéos, la vidéo-surveillance, ou encore l'assistance aux personnes âgées. Dans la première partie de nos travaux, nous développons une méthode de reconnaissance d'actions élémentaires basée sur l'estimation du mouvement dans des vidéos. Les points critiques du champ vectoriel obtenu, ainsi que leurs trajectoires, sont estimés à différentes échelles spatio-temporelles. La fusion tardive de caractéristiques d'orientation de mouvement et de variation de gradient, dans le voisinage des points critiques, ainsi que la description fréquentielle des trajectoires, nous permet d'obtenir des taux de reconnaissance parmi les meilleurs de la littérature. Dans la seconde partie, nous construisons une méthode de reconnaissance d'activités en considérant ces dernières comme un enchainement temporel d'actions élémentaires. Notre méthode de reconnaissance d'actions est utilisée pour calculer la probabilité d'actions élémentaires effectuées au cours du temps. Ces séquences de probabilité évoluent sur une variété statistique appelée simplexe sémantique. Une activité est finalement représentée comme une trajectoire dans cet espace. Nous introduisons un descripteur fréquentiel de trajectoire pour classifier les différentes activités humaines en fonction de la forme des trajectoires associées. Ce descripteur prend en compte la géométrie induite par le simplexe sémantique. / This thesis focuses on the characterization and recognition of human activities in videos. This research domain is motivated by a large set of applications such as automatic video indexing, video monitoring or elderly assistance. In the first part of our work, we develop an approach based on the optical flow estimation in video to recognize human elementary actions. From the obtained vector field, we extract critical points and trajectories estimated at different spatio-temporal scales. The late fusion of local characteristics such as motion orientation and shape around critical points, combined with the frequency description of trajectories allow us to obtain one of the best recognition rate among state of art methods. In a second part, we develop a method for recognizing complex human activities by considering them as temporal sequences of elementary actions. In a first step, elementary action probabilities over time is calculated in a video sequence with our first approach. Vectors of action probabilities lie in a statistical manifold called semantic simplex. Activities are then represented as trajectories on this manifold. Finally, a new descriptor is introduced to discriminate between activities from the shape of their associated trajectories. This descriptor takes into account the induced geometry of the simplex manifold.

Nous étudions, dans la première partie de notre thèse, les polysimplexes d’un espace euclidien de dimension quelconque, c’est-à-dire les objets consistant en une juxtaposition de simplexes réguliers (de tétraèdres si la dimension est 3) accolés le long de leurs faces. Nous étudions principalement le groupe des symétries de ces polysimplexes. Nous présentons une façon de représenter un polysimplexe à l’aide d’un diagramme. Ceci fournit une classification complète des polysimplexes à similitude près. De plus, le groupe des symétries se déduit du groupe des automorphismes du diagramme. Il découle en particulier de notre étude qu’en dimension supérieure à 2, une telle structure ne possède jamais deux faces parallèles et ne contient jamais de circuit fermé de simplexes.<p><p>Dans la seconde partie de notre thèse, nous abordons un problème classique de combinatoire :l’énumération des pavages d’un rectangle mxn à l’aide de dominos. Klarner et Pollack ont montré qu’en fixant m la suite obtenue vérifie une relation de récurrence linéaire à coefficients constants. Nous établissons une nouvelle méthode nous permettant d’obtenir la fonction génératrice correspondante et la calculons pour m <= 16, alors qu’elle n’était connue que pour m <= 10.<p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Les plantes médicinales Diplotaxis harra et Diplotaxis simplex occupent une place importante dans la pharmacopée traditionnelle grâce à leurs compositions variées en métabolites secondaires tels que les flavonoïdes. Ces derniers jouent un rôle important dans plusieurs activités biologiques, notamment anti-inflammatoires et anti-cancéreuses. Dans ce contexte, et à la recherche de molécules bioactives dans D. harra et D. simplex, nous avons mis au point un nouveau modèle d'étude in vitro des cellules souches à l'origine des pathologies inflammatoires et cancéreuses coliques où leur survie dépend de l'activation de la Glycogène Synthase Kinase 3beta (GSK3beta) en aval du récepteur de protéases inflammatoires PAR2. Ce modèle a permis la purification bioguidée de glucoflavonoïdes à partir d'un extrait méthanolique des fleurs de D. harra capables d'inhiber GSK3beta via la voie PKC. Ainsi, l'Isorhamnétine-3,7-di-O-glucoside s'est révélé cytotoxique vis à vis des cellules inflammatoires ou cancéreuses coliques tout en épargnant les cellules normales. D'autre part, en raison de l'intérêt grandissant porté aux fractions volatiles en thérapeutique, nous avons étudié les compositions chimiques et les activités antioxydantes des fractions volatiles des feuilles et des fleurs de D. simplex. En se basant sur la technique chromatographique en phase gazeuse couplée à la spectrométrie de masse (GC-MS), nous avons montré que les deux fractions volatiles contiennent des quantités importantes de composés soufrés/azotés, parmi lesquels le 5-methylthiopentanenitrile et le 1-isothiocyanatobutane pourraient être impliqués dans l'effet antioxydant des fleurs de D. simplex. En conclusion, nos travaux ont permis de révéler l'axe PAR2/GSK3beta comme une nouvelle voie de survie des cellules souches coliques et l'intérêt thérapeutique des glucoflavonoïdes et des fractions volatiles de l'espèce Diplotaxis. / The medicinal plants Diplotaxis harra and Diplotaxis simplex occupy an important place in traditional medicine due to their varied compositions in secondary metabolites such as flavonoids. Flavonoids play an important role in many biological activities, including inflammation and cancer. In this context and in search of bioactive molecules in D. harra and D. simplex, we have developed a new study model, in vitro, where colonic stem cells causing inflammatory diseases and colorectal cancer survive through the activation of Glycogen Synthase Kinase 3beta (GSK3beta) downstream of inflammatory proteases PAR2 receptor. This model allowed the bio-guided purification of glucoflavonoids from a methanol extract of D. harra flowers able to inhibit GSK3beta via a PKC-dependent pathway. Thus, isorhamnetin-3,7-di-O-glucoside was found to be cytotoxic against inflammatory or colon cancer cells while sparing normal cells. On the other hand, due to the growing interest in therapeutic volatile fractions, we studied the chemical composition and antioxidant activity of volatile fractions of leaves and flowers of D. simplex. Based on the gas chromatography mass spectrometry technique (GC-MS), we have shown that both volatile fractions contain significant amounts of sulfur/nitrogen compounds, including 5-methylthiopentanenitrile and 1-isothiocyanatobutane, which might be involved in the antioxidant effect of flowers from D. simplex. In conclusion, our work revealed the axis PAR2/GSK3beta as a new survival pathway for colon stem cells and the therapeutic value of glucoflavonoids and volatile fractions of Diplotaxis species.