Les travaux effectués au cours de cette thèse portent principalement sur la construction de nouvelles bornes du comportement effectif des matériaux biphasés de type matrice-inclusions à comportement linéaire élastique. Dans un premier temps, afin d’encadrer le comportement effectif, nous présentons une nouvelle approche numérique, inspirée des travaux de Huet (J. Mech. Phys. Solids 1990 ; 38:813-41), qui repose sur le calcul des comportements apparents associés à des volumes élémentaires (VE) non-carrés construits à partir d'assemblages de cellules de Voronoï, chaque cellule contenant une inclusion entourée de matrice. De tels VE non-carrés permettent d'éviter l'application directe des CL sur les inclusions à l’origine d’une surestimation artificielle des comportements apparents. En utilisant les théorèmes énergétiques de l'élasticité linéaire et des procédures de moyennisation appropriées portant sur les comportements apparents, un nouvel encadrement du comportement effectif est obtenu. Son application au cas d'un composite biphasé, constitué d'une matrice isotrope et de fibres cylindriques parallèles et identiques distribuées aléatoirement dans le plan transverse, conduit à des bornes plus resserrées que celles obtenues par Huet. En nous appuyant sur cette nouvelle procédure numérique, nous avons ensuite réalisé une étude statistique des comportements apparents à l'aide de simulations de type Monté Carlo. Puis, à partir des tendances issues de cette étude statistique, nous avons proposé et mis en œuvre de nouveaux critères de tailles de VER. / This work is devoted to the derivation of improved bounds for the effective behavior of random linear elastic matrix-inclusions composites. In order to bounds their effective behavior, we present a new numerical approach, inspired by the works of Huet (J. Mech. Phys. Solids 1990 ; 38:813-41), which relies on the computation of the apparent behaviors associated to non square (or non cubic) volume elements (VEs) comprised of Voronoï cells assemblages, each cell being composed of a single inclusion surrounded by the matrix. Such non-square VEs forbid any direct application of boundary conditions to particles which is responsible for the artificial overestimation of the apparent behaviors observed for square VEs. By making used of the classical bounding theorems for linear elasticity and appropriate averaging procedures, new bounds are derived from ensemble averages of the apparent behavior associated with non square VEs. Their application to a two-phase composite composed of an isotropic matrix and aligned identical fibers randomly and isotropically distributed in the transverse plane leads to sharper bounds than those obtained by Huet. Then, by making use of this new numerical approach, a statistical study of the apparent behavior is carried out by means of Monte Carlo simulations. Subsequently, relying on the trends derived from this study, some proposals to define RVE criteria are presented.

Les progrès technologiques récents en imagerie par résonance magnétique (IRM) ont ouvert la voie à une résolution spatiale de l’ordre de quelques microns, et donc à l’imagerie de cellules biologiques. Dans le cadre de ce projet, nous avons réalisé des expériences de microscopie IRM sur le système nerveux de l’aplysie (Aplysia californica), particulièrement adapté de par sa simplicité et de par la très grande taille de ses neurones, en vue d’étudier des processus à échelle cellulaire avec divers contrastes IRM. Les expériences d’imagerie ont été effectuées sur un aimant horizontal 17.2 Tesla, à des résolutions spatiales jusqu’à 25 µm isotrope. Le travail initial a consisté en la conception et fabrication de micro-antennes radiofréquences adaptées à la taille de neurones uniques et de ganglions. La première partie du projet a porté sur l’utilisation de l’ion manganèse (Mn2+) comme traceur de réseaux neuronaux dans le ganglion buccal de l’aplysie. Le manganèse (Mn) est un agent de contraste IRM qui pénètre dans les neurones par les canaux de calcium. La cartographie des projections axonales des neurones moteurs du ganglion dans chacun des nerfs périphériques a été établie. Il a également été démontré l’existence d’un transport actif du Mn2+ au sein du réseau neuronal activé par le neurotransmetteur dopamine. Dans un second temps, on s’est intéressé à deux méthodes de mesure de diffusion par IRM, à échelle microscopique. D’une part, un mécanisme de pondération en diffusion, DESIRE (Diffusion Enhancement of SIgnal and REsolution), original et particulièrement adapté à des échantillons petits, a été exploré. La séquence DESIRE a été implémentée en deux dimensions et testée avec succès sur fantôme. Le rehaussement mesuré était en accord avec les prévisions théoriques. Le grand défi à venir sera d’utiliser cette séquence pour acquérir des images de tissu biologique pondérées en diffusion avec un contraste unique. D’autre part, une séquence plus « classique » a été implémentée pour mesurer le coefficient de diffusion apparent (ADC) dans le tissu nerveux. Il s’agit d’une DP-FISP (Diffusion Prepared Fast Imaging with Steady-state free Precession) en trois dimensions, qui répond aux critères de résolution spatiale et de rapidité, avec un minimum d’artefacts. Cette séquence a permis d’étudier l’évolution de l’ADC de l’eau à différentes échelles du tissu nerveux en réponse à un stress cellulaire. Les deux sollicitations retenues étaient un choc hypotonique ou l’ajout d’ouabaïne. Des mesures d’ADC ont été effectuées sur des corps neuronaux isolés et sur du tissu de ganglion, avant et après sollicitation. Les deux types de stress ont entraîné une augmentation de l’ADC dans la cellule et une diminution globale de l’ADC dans le tissu. Ces résultats soutiennent l’hypothèse que la diffusion ralentie de l’eau habituellement observée dans un tissu ischémié (ou dans d’autres conditions associées à un gonflement cellulaire) est due à l’augmentation de surface membranaire. / Recent progress in magnetic resonance imaging (MRI) has opened the way for micron-scale resolution, and thus for imaging biological cells. In this thesis work, we performed magnetic resonance microscopy (MRM) on the nervous system of Aplysia californica, a model particularly suited due to its simplicity and to its very large neuronal cell bodies, in the aim of studying cellular-scale processes with various MR contrasts. Experiments were performed on a 17.2 Tesla horizontal magnet, at resolutions down to 25 µm isotropic. Initial work consisted in conceiving and building radiofrequency microcoils adapted to the size of single neurons and ganglia. The first major part of the project consisted in using the manganese ion (Mn2+) as neural tract tracer in the buccal ganglia of Aplysia. Manganese is an MR contrast agent that enters neurons via voltage-gated calcium channels. We performed the mapping of axonal projections from motor neurons into the peripheral nerves of the buccal ganglia. We also confirmed the existence of active Mn2+ transport inside the neural network upon activation with the neurotransmitter dopamine. In the second major part of the project, we tested the potential of two diffusion MRI sequences for microscopy. On the one hand, we explored a very original mechanism for diffusion weighting, DESIRE (Diffusion Enhancement of SIgnal and REsolution), particularly suited for small samples. The two-dimensional DESIRE sequence was implemented and successfully tested on phantoms. The measured enhancement was consistent with theoretical predictions. Using this sequence to produce diffusion weighted images with an unprecedented contrast in biological tissue remains a challenge. On the other hand, a more “standard” sequence was implemented to measure the apparent diffusion coefficient (ADC) in nervous tissue with MRM. This sequence was a three-dimensional DP-FISP (Diffusion Prepared Fast Imaging with Steady-state free Precession), which met criteria for high resolution in a short acquisition time, with minimal artifacts. Using this sequence, we studied the changes in water ADC at different scales in the nervous system, triggered by cellular challenges. The challenges were hypotonic shock or exposure to ouabain. ADC measurements were performed on single isolated neuronal bodies and on ganglia tissue, before and after challenge. Both types of stress produced an ADC increase inside the cell and an ADC decrease at tissue level. The results favor the hypothesis that the increase in membrane surface area associated with cell swelling is responsible for the decrease of water ADC in tissue, typically measured in ischemia or other conditions associated with cell swelling.

La décision à l’hôpital public est un objet complexe, qui donne lieu à de fréquentesmodifications législatives et réglementaires. Déterminant essentiel de la qualité duservice rendu, les modalités d’exercice du pouvoir de décision à l’hôpital sontdéfinies par les textes, mais aussi par les pratiques des acteurs.Cette thèse traite des relations entre les deux catégories d’acteurs qui dominent lesinteractions ayant pour objet la décision : les directeurs et les médecins.Ces acteurs ont un rôle majeur et complémentaire dans les deux phases du processusde décision. D’une part, ils assurent une grande partie de la préparation desdécisions, dans le cadre d’échanges informels et au sein des instances. Directeurs etmédecins ont donc ainsi un rôle important dans la délibération qui précède ladécision. D’autre part, ils ont un rôle essentiel dans la prise de décision elle-même.Au-delà du pouvoir juridique de décider, qui revient au directeur, chefd’établissement, directeurs et médecins s’influencent réciproquement dans la prisede la décision.Ces travaux visent à démontrer que les relations entre directeurs et médecins dansle cadre de la décision à l’hôpital public sont des relations de dialogue, notammentdans la préparation des décisions. Ce sont aussi des relations de pouvoir, enparticulier dans la phase de prise de décision.Notre étude présente enfin des propositions visant à améliorer la qualité du processusde décision à l’hôpital public. Ces propositions tendent à renforcer la qualité dudialogue par le rapprochement des formations des acteurs, à augmenter latransparence, et à renforcer les supervisions externes des débats hospitaliers. / Decision-making in a public hospital is complex and subject to frequent legislative and regulatory changes. The rules of decision-making – an essential determinant of service quality – are defined not only by Law and regulations, but also by actual practices.This Dissertation analyses the relationships between the two types of actors predominantly involved in decision-making: managers and physicians.These actors hold a major and complementary role in the two phases of the decision-making process. First, they take charge of a large part of the preparation of decisions, thanks to informal exchanges and formal committee meetings. Managers and physicians thus have an important role in the preliminary discussions preceding the decision. Second, they also play a major role in the decision-taking stage itself. Beyond the decision power – that belongs to the manager. Managers and physicians have a reciprocal influence in the final decision-making process.This study aims at demonstrating that the relationships between managers and physicians in the process of decision-making in a public hospital are based on dialogue, in particular in the preparation of decisions. They are also power relationships, in particular in the final phase of decision-making.Last, this Dissertation offers suggestions to improve the quality of the decision-making process in public hospitals. These suggestions aim at reinforcing the quality of dialogue by harmonizing the formation of the actors, improving transparency, and reinforcing the external supervision of debates within the hospital.

Lors d'une opération d'usinage, l'intégrité de la surface usinée et l’optimisation du procédé sont conditionnées par les paramètres de coupe (vitesses de coupe et d’avance, géométrie et matériau de l'outil...). Certaines conditions de coupe peuvent induire des effets indésirables tels que des vibrations importantes, des efforts de coupe excessifs et une usure prématurée de l'outil, conduisant à des qualités de surfaces médiocres. Dans l’industrie, l’utilisation d'approches empiriques pour opérer ce choix se révèle couteux et difficilement exploitable. Le développement d’outils de simulation basés sur des modèles prédictifs s’avère nécessaire. Ces modèles permettent de maitriser et de comprendre les phénomènes thermomécaniques aux interfaces outil-copeau et outil-pièce qui conditionnent l'intégrité de la surface usinée ainsi que la durée de vie de l'outil de coupe. L'objectif de la thèse est la modélisation des effets thermomécaniques en usinage avec des approches hybrides 'Analytique-c. Ceci permet d'analyser l'interaction entre les conditions de coupe du procédé d'usinage, le comportement du matériau et les conditions tribologiques aux interfaces outil-copeau et outil-pièce (contact collant-glissant, partage de la source de chaleur due au frottement). Le travail comporte également une validation expérimentale pour la coupe orthogonale à sec. Le modèle proposé est basé sur les développements suivants: (i) mise en place d'une 'Approche 1D par Tranche' pour la prise en compte de l'écoulement de la matière dans la zone primaire de cisaillement du copeau, (ii) modélisation du problème thermique transitoire non linéaire dans le système 'copeau-outil-pièce' en couplant une formulation EF de type Petrov-Galerkin avec la méthode de Newton-Raphson et une intégration implicite dans le temps, (iii) une nouvelle formulation de la distribution de pression le long de la face de coupe de l'outil, (iv) une nouvelle approche pour gérer le partage de la source de chaleur par friction à l'interface outil-copeau. La démarche proposée permet de mettre en place une modélisation thermomécanique de l'interaction outil-matière applicable aux procédés industriels comme le perçage très utilisé dans le domaine aéronautique. Comparée aux simulations basées sur la méthode des Éléments Finis, l'approche développée requiert un temps de calcul de l'ordre de quelques minutes avec une précision comparable / In dry machining, the thermomechanical process of chip formation, the tool wear and the surface integrity depend strongly on the tribological conditions along the tool rake face. Besides, the friction conditions at the tool-chip interface and along the round cutting edge are very complex. It should be noted that to understand the friction effects in machining, we have to analyse the inherent relationship among, the cutting conditions (cutting and feed velocities, tool geometry), the workpiece material behaviour, the thermomechanical characteristics of the tool material, the frictional heat partition in the sliding zone and the friction conditions at the tool-chip and tool-workpiece interfaces. Due to the problem complexity, it appears that despite many works on machining, the understanding of the effect of friction conditions requires further investigations. In the present work, to identify the interaction between the thermomechanical phenomena at the tool-chip interface and the material flow in the primary shear zone; an analytical model has been coupled with a finite element approach. For the tool rake face, a new pressure model was developed. The transient nonlinear thermal problem in the workpiece-tool-chip system has been solved by using a FE model based on the Petrov-Galerkin formulation. The coupling between the primary shear zone (PSZ) (chip formation), the secondary shear zone (SSZ) (sticking zone) and the frictional heat at the sliding zone has been taking into account. The model allows to determine in a fast and simple way several significant machining parameters as: (i) the cutting forces, (ii) the temperature distribution in the tool-chip-workpiece system, (iii) the heat flux from the PSZ to the workpiece, (iv) the tool-chip contact length, (v) the frictional heat partition and (vi) the apparent friction coefficient. The proposed model allows to analyze different industrial machining processes such as drilling and milling

Toward the objective to create or to replace impaired tissues, it is essential to establish a culture process allowing tissue growth in vitro . The Petri dish culture or the traditional 2D culture has only a limited potential, mainly caused by a poor oxygen mass transfer to feed larger tissue constructs. In this project, an autonomous and complete bioprocess has been built to fullfill these needs. The developed reactor is versatile because many cell culture chamber designs can be connected to it. Two proportional-integral algorithms (PI) can control the dissolved oxygen concentration and the pH. The pressure, the temperature and mass flow rate are recorded in real time. An actuator allows mimicking the cardiac output flow. In this mémoire , it will be demonstrated how the reactor has been optimized to reduce the risk of bioburden. Also, the procedures to develop the control tools of the PI algorithm will be detailed. To characterize the reactor, a RTD study will be presented. To characterize the cell culture chamber, a permeability analysis using fluorescent microscopy and magnetic resonance imaging (MRI) will be exposed. Finally, two cell culture chamber designs to orient microvessel formation have been tested and these results will be presented.

FundaÃÃo de Amparo à Pesquisa do Estado do Cearà / In order to evaluate the effects of replacing corn for broken rice (QA) and the inclusion of parboiled rice bran (FIAP) in rations for meat quails, two experiments were conducted in the period 7 to 49 days age. In each trial, 288 quails with seven days of age were distributed in a completely randomized design with six treatments and six replications of eight birds for experimental unit. In the first experiment, was tested the levels of 0, 20, 40, 60, 80 and 100% of replacement corn by broken rice and it was observed that the replacement of corn for broken rice did not significantly influence the performance and carcass characteristics of quails at different stages of creation, neither economic viability. In the second experiment, the treatments were a control diet without the inclusion of FIAP, and the other containing 5, 10, 15, 20 and 25% of FIAP. There was a linear decrease in the apparent digestibility of dry matter (CDMS) and crude energy (CDEB) and a linear increase of apparent metabolizable energy (EMA) and apparent metabolizable energy corrected for nitrogen (EMAn) with the inclusion of FIAP in rations, above 5%. Therefore, there was a linear decrease in feed intake and weight gain, without influence in feed conversion, carcass characteristics and parameters of bone quality. Although there was some reduction parameters when FIAP increased above 5%, the performance of birds fed with different levels of FIAP was similar in relation to the control group. Furthermore, the use until 25% of FIAP provided better economic viability. It can be argued that the broken rice can replace corn in the feeding of meat quails at levels up to 100%, while the FIAP can be included in rations in proportions of up to 25% without affecting carcass characteristics. / Com o objetivo de avaliar os efeitos da substituiÃÃo do milho por quirera de arroz (QA) e da inclusÃo do farelo integral de arroz parboilizado (FIAP) nas raÃÃes de codornas do tipo corte, foram realizados dois experimentos no perÃodo de 7 a 49 dias de idade. Em cada experimento, 288 codornas com sete dias de idade foram distribuÃdas em um delineamento inteiramente casualizado, com seis tratamentos e seis repetiÃÃes de oito aves por unidade experimental. No primeiro experimento, foram testados os nÃveis de 0, 20, 40, 60, 80 e 100% de substituiÃÃo do milho pela quirera de arroz e observou-se que nÃo houve influencia significativa sobre o desempenho e as caracterÃsticas de carcaÃa das aves, nas diferentes fases de criaÃÃo, nem tÃo pouco sobre a viabilidade econÃmica. No segundo experimento, os tratamentos consistiram de uma raÃÃo controle, sem a inclusÃo de FIAP, e as demais contendo 5, 10, 15, 20 e 25% de FIAP. Houve decrÃscimo linear nos coeficientes de digestibilidade da matÃria seca (CDMS) e energia bruta (CDEB), bem como aumento linear da energia metabolizÃvel aparente (EMA) e energia metabolizÃvel aparente corrigida para nitrogÃnio (EMAn) com a inclusÃo do FIAP nas raÃÃes, acima de 5%. Observou-se ainda reduÃÃo linear no consumo de raÃÃo e ganho de peso, sem, contudo influenciar na conversÃo alimentar, caracterÃsticas de carcaÃa e parÃmetros de qualidade Ãssea. Embora tenha ocorrido reduÃÃo de alguns parÃmetros, quando se aumentou o FIAP acima de 5%, nÃo houve prejuÃzo significativo nos resultados de desempenho das aves alimentadas com os diferentes nÃveis do FIAP em relaÃÃo Ãs do grupo controle. O uso de atà 25% de FIAP proporcionou a melhor viabilidade econÃmica. Pode-se afirmar que a quirera de arroz pode substituir o milho na alimentaÃÃo de codornas de corte em nÃveis de atà 100%, enquanto, o FIAP pode ser incluÃdo nas raÃÃes em proporÃÃes de atà 25%, sem afetar as caracterÃsticas de carcaÃa.

Made available in DSpace on 2017-07-10T19:24:29Z (GMT). No. of bitstreams: 1 LEANDRO BOHNENBERGER.pdf: 1385012 bytes, checksum: 8cb9261c7084a7005906fd2de4b19855 (MD5) Previous issue date: 2008-07-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Although cassava leaves are rich in proteins, vitamins and minerals and are easily found at low prices, their direct consumption is limited due to the presence of anti-nutritious and/or toxic substances. Aiming to create alternatives to the use of these leaves, the present paper aimed to determine the coefficients of apparent digestibility (AD) from the dry matter (DM), crude protein (CP) and crude energy (CE) of cassava leaf protein concentrate (CLPC) for Nile Tilapia, and to evaluate its inclusion in Nile Tilapia food. The CLPC has been extracted through isoeletric precipitation, method described by CEREDA & VILPOUX (2003). In the CLPC, it has been determined the perceptual of crude protein (CP), ether extract (EE), ashes, dry matter (DM) and crude energy (CE), which have shown 48.42%, 13.57%, 3.48%, 93.01% and 5527 Kcal/kg., respectively. 24 tilapias with an average weight of 86.92 ± 36.70 g have been used. The animals have been submitted to fecal collection methodology, through sedimentation, in tanks with funneled shapes. The DM, CP, and CE of CLPC have presented AD of 33.06%, 66.57% and 30.06%, respectively, thus, showing digestible protein and energy values of 32.23% and 1661.13 kcal of DE/kg. In order to evaluate CLPC inclusion in Nile Tilapia food, 300 larvae at the age of 7 days old have been used, which were distributed in 20 aquariums with capacity for 30 liters of useful volume, in a fully randomized outline with five treatments and four repetitions, pointing out that the experimental unit is consisted of an aquarium with 15 tilapia larvae. Five isoproteic and isoenergetic diets have been elaborated containing 38.6% of digestible protein and 3300 kcal of DE/kg of diets with level of 0, 5, 10, 15 and 20% of CLPC inclusion. At the end of the experimental time, differences have not been noticed (W>0.05) on the final average weight, weight gain, final length and survival of larvae which were fed with diets containing CLPC. It is concluded that CLPC is a protean food and it may be used in diets for tilapia in initial phase in up to 20% of inclusion without causing performance and survival harms. / Folhas de mandioca são ricas em proteínas, vitaminas e minerais e, apesar de serem facilmente encontradas a baixo custo, seu consumo direto fica limitado devido à presença de substâncias antinutritivas e/ou tóxicas. Na busca de criar alternativas para o uso dessas folhas, o presente trabalho objetivou determinar os coeficientes de digestibilidade aparente (CD) da matéria seca (MS), proteína bruta (PB), e energia bruta (EB) do concentrado protéico de folhas de mandioca (CPFM) para a tilápia do Nilo, e avaliar sua inclusão na alimentação da tilápia. O concentrado foi extraído das folhas de mandioca por precipitação isoelétrica, método descrito por CEREDA & VILPOUX (2003). Foram determinados no concentrado protéico de folhas de mandioca (CPFM) o percentual de proteína bruta (PB), extrato etéreo (EE), cinzas, matéria seca (MS) e energia bruta (EB), que apresentaram, 48,42%, 13,57%, 3,48%, 93,01% e 5527 Kcal/Kg, respectivamente. Foram utilizadas 24 tilápias com peso médio de 86,92 ± 36,70g. Os animais foram submetidos à metodologia de coleta de fezes, por sedimentação, em tanques afunilados. A MS, PB e EB do CPFM apresentaram CD de 33,06%, 66,57% e 30,06%, respectivamente. Apresentando valores de proteína e energia digestíveis de 32,23% e 1661,13 Kcal de ED/Kg. Para avaliar a inclusão do CPFM na alimentação da tilápia, foram utilizadas 300 larvas com idade de sete dias, distribuídas em 20 aquários com capacidade para 30 L de volume útil, em um delineamento inteiramente casualizado, com cinco tratamentos e quatro repetições, sendo a unidade experimental constituída por um aquário com 15 larvas de tilápia. Foram elaboradas cinco rações isoprotéicas e isoenergéticas com 38,6% de proteína digestível e 3300 Kcal de ED/Kg de ração com níveis de 0, 5, 10, 15 e 20% de inclusão do CPFM. Ao final do período experimental, não foram observadas diferenças (P>0,05) nas médias de peso final, ganho de peso, comprimento final e sobrevivência das larvas alimentadas com rações, incluindo CPFM. Conclui-se que o CPFM é um alimento protéico e que pode ser utilizado em rações para tilápias em fase inicial em até 20% de inclusão sem causar prejuízos no desempenho e sobrevivência.

Made available in DSpace on 2017-05-12T14:47:48Z (GMT). No. of bitstreams: 1 LEANDRO BOHNENBERGER.pdf: 1385012 bytes, checksum: 8cb9261c7084a7005906fd2de4b19855 (MD5) Previous issue date: 2008-07-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Although cassava leaves are rich in proteins, vitamins and minerals and are easily found at low prices, their direct consumption is limited due to the presence of anti-nutritious and/or toxic substances. Aiming to create alternatives to the use of these leaves, the present paper aimed to determine the coefficients of apparent digestibility (AD) from the dry matter (DM), crude protein (CP) and crude energy (CE) of cassava leaf protein concentrate (CLPC) for Nile Tilapia, and to evaluate its inclusion in Nile Tilapia food. The CLPC has been extracted through isoeletric precipitation, method described by CEREDA & VILPOUX (2003). In the CLPC, it has been determined the perceptual of crude protein (CP), ether extract (EE), ashes, dry matter (DM) and crude energy (CE), which have shown 48.42%, 13.57%, 3.48%, 93.01% and 5527 Kcal/kg., respectively. 24 tilapias with an average weight of 86.92 ± 36.70 g have been used. The animals have been submitted to fecal collection methodology, through sedimentation, in tanks with funneled shapes. The DM, CP, and CE of CLPC have presented AD of 33.06%, 66.57% and 30.06%, respectively, thus, showing digestible protein and energy values of 32.23% and 1661.13 kcal of DE/kg. In order to evaluate CLPC inclusion in Nile Tilapia food, 300 larvae at the age of 7 days old have been used, which were distributed in 20 aquariums with capacity for 30 liters of useful volume, in a fully randomized outline with five treatments and four repetitions, pointing out that the experimental unit is consisted of an aquarium with 15 tilapia larvae. Five isoproteic and isoenergetic diets have been elaborated containing 38.6% of digestible protein and 3300 kcal of DE/kg of diets with level of 0, 5, 10, 15 and 20% of CLPC inclusion. At the end of the experimental time, differences have not been noticed (W>0.05) on the final average weight, weight gain, final length and survival of larvae which were fed with diets containing CLPC. It is concluded that CLPC is a protean food and it may be used in diets for tilapia in initial phase in up to 20% of inclusion without causing performance and survival harms. / Folhas de mandioca são ricas em proteínas, vitaminas e minerais e, apesar de serem facilmente encontradas a baixo custo, seu consumo direto fica limitado devido à presença de substâncias antinutritivas e/ou tóxicas. Na busca de criar alternativas para o uso dessas folhas, o presente trabalho objetivou determinar os coeficientes de digestibilidade aparente (CD) da matéria seca (MS), proteína bruta (PB), e energia bruta (EB) do concentrado protéico de folhas de mandioca (CPFM) para a tilápia do Nilo, e avaliar sua inclusão na alimentação da tilápia. O concentrado foi extraído das folhas de mandioca por precipitação isoelétrica, método descrito por CEREDA & VILPOUX (2003). Foram determinados no concentrado protéico de folhas de mandioca (CPFM) o percentual de proteína bruta (PB), extrato etéreo (EE), cinzas, matéria seca (MS) e energia bruta (EB), que apresentaram, 48,42%, 13,57%, 3,48%, 93,01% e 5527 Kcal/Kg, respectivamente. Foram utilizadas 24 tilápias com peso médio de 86,92 ± 36,70g. Os animais foram submetidos à metodologia de coleta de fezes, por sedimentação, em tanques afunilados. A MS, PB e EB do CPFM apresentaram CD de 33,06%, 66,57% e 30,06%, respectivamente. Apresentando valores de proteína e energia digestíveis de 32,23% e 1661,13 Kcal de ED/Kg. Para avaliar a inclusão do CPFM na alimentação da tilápia, foram utilizadas 300 larvas com idade de sete dias, distribuídas em 20 aquários com capacidade para 30 L de volume útil, em um delineamento inteiramente casualizado, com cinco tratamentos e quatro repetições, sendo a unidade experimental constituída por um aquário com 15 larvas de tilápia. Foram elaboradas cinco rações isoprotéicas e isoenergéticas com 38,6% de proteína digestível e 3300 Kcal de ED/Kg de ração com níveis de 0, 5, 10, 15 e 20% de inclusão do CPFM. Ao final do período experimental, não foram observadas diferenças (P>0,05) nas médias de peso final, ganho de peso, comprimento final e sobrevivência das larvas alimentadas com rações, incluindo CPFM. Conclui-se que o CPFM é um alimento protéico e que pode ser utilizado em rações para tilápias em fase inicial em até 20% de inclusão sem causar prejuízos no desempenho e sobrevivência.

<p>The aim of this study was to investigate the effect the plant matrix and the structure of the flavonoid (i.e. whether aglycone or glycoside) may have on the gastrointestinal uptake and metabolism of luteolin derivatives from Artemisia afra traditional plant medicine. Specifically, how these two factors influenced the intestinal uptake and disposition of luteolin derivatives in pure and in Artemisia afra plant extract forms were to be assessed by investigating the uptake and metabolism of the luteolin derivatives in human intestinal epithelial Caco-2 cells and the perfused rat intestinal loop. To realize this aim, the following were determined: (1) identification and characterization of major luteolin derivatives found in Artemisia afra, (2) the effect of the plant matrix on the uptake of luteolin derivatives in Artemisia afra aqueous-extract forms across the Caco-2 cell monolayer, (3) the effect of the plant matrix on the absorption and metabolism of luteolin derivatives in Artemisia afra aqueous-extract forms in the perfused rat small intestine, (4) the effect of gut contents on the uptake and metabolism of luteolin derivatives in intestinal loop and (5) the metabolic profiles of luteolin derivatives obtained for the pure solutions versus plant aqueous extract solutions in Caco-2 cells and the rat intestine.</p>

L'âge a de tout temps constitué un attribut identitaire important. Nous avons développé au fil de l'évolution une aptitude innée à classer les individus en fonction de leur âge. Cette classification s'appuie en grande partie sur le visage et sur les transformations anatomiques qu'il subit au cours du temps. De plus en plus de traitements cosmétiques, dermatologiques et d'interventions chirurgicales s'attaquant à un signe ou un groupe de signes spécifiques du vieillissement sont mis en oeuvre pour annuler, ou tout au moins masquer partiellement l'effet du temps sur le visage. On peut dès lors s'interroger sur l'influence de chacun des signes sur notre capacité à prédire l'âge d'un individu en observant son visage. Afin de construire un algorithme capable de déterminer l'âge d'individus à partir de leurs photos, nous nous sommes intéressés aux signes du vieillissement et à leur impact sur l'âge apparent. Dans un premier temps, nous avons déterminé et analysé les transformations anatomiques qui altèrent le visage à partir de l'âge adulte (au-delà de 20 ans). Puis nous avons étudié les signes sur lequel on se base pour prédire l'âge d'une personne. Enfin, nous avons construit et validé un modèle prédictif de l'âge en s'appuyant sur les observations précédentes. Transformations anatomiques du visage avec l'âge : La prévalence d'un certain nombre de signes de vieillissement (rides, tâches brunes, forme du visage...) a été mesurée sur un panel représentatif de femmes volontaires âgées de 20 à 74 ans. Ces données ont permis d'établir la cinétique d'apparition de ces signes. Appréciation subjective de l'âge: Il s'agissait de déterminer les signes sur lesquels un observateur s'appuie lorsqu'il évalue l'âge d'un sujet. Pour ce faire, nous avons demandé à un panel constitué de 48 observateurs d'attribuer un âge aux volontaires sur lesquelles nous avions précédemment mesuré les signes du vieillissement. Nous avons confirmé avec ce groupe d'observateurs que la perception de l'âge est liée au sexe et à l'âge de l'observateur. De plus, à l'aide d'une régression PLS (Partial Least Square régression), nous avons établi des relations entre les signes du vieillissement et l'âge observé et démontré que selon que l'on soit jeune ou âgé, un homme ou une femme, on n'exploite pas les mêmes signes de vieillissement pour prédire l'âge.Modèle de prédiction : Enfin, nous avons proposé un modèle s'appuyant sur la régression PLS pour prédire automatiquement l'âge à partir des photos du visage. Ce modèle présente la particularité d'associer, dans une approche unifiée, les signes relatifs à la couleur, à la forme et à la texture du visage, à l'âge des sujets. A l'instar des Modèles Actifs D'apparence (AAM), le modèle construit vise à réduire fortement l'information portée par l'ensemble des pixels du visage. Toutefois, ce dernier est supervisé : Il est donc très approprié dans notre contexte puisque que l'on peut mettre en oeuvre une procédure d'apprentissage pilotée par le but. Les performances sont de fait comparables à celles des humains.