Tesis sobre el tema "Modèles de vieillissement"
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Descamps, Olivier. "Sress oxydant et vieillissement : aspects mitochondriaux et stratégies nutritionnelles anti-cancer et anti-vieillissement chez la souris OF1". Université Joseph Fourier (Grenoble), 2004. http://www.theses.fr/2004GRE18008.
Texto completoOur thesis aimed to establish new perspectives about the link between the antioxidant status, the aging process and the cancer process, considering essentially the role played by mitochondria. A major part of our studies was devoted to evaluate nutritional strategies to prevent aging and cancer. Our objectives were to study the effects of calorie restriction or alternate feeding, selenium supplementation, that all proved striking efficacy, in contrast with the lack of effect of DHEA sulfate supplementation. A number of correlation studies between aging, longevity and various parameters of oxidative stress were evaluated: link between memory and antioxidant enzymes in brain and hippocampus, link between longevity and urinary level of 8-oxo-dGuo, the later appearing as highly significant. We concluded the thesis by the analysis of the correlation between the antioxidative defense system and the insect longevity
Nguyen, Thanh Hoi. "Vieillissement artificiel et vieillissement naturel en ambiance tropicale de composites modèles époxy/verre : approche nanoscopique de l'étude des interphases". Phd thesis, Toulon, 2013. http://tel.archives-ouvertes.fr/tel-00942583.
Texto completoNguyen, Thanh Hoi. "Vieillissement artificiel et vieillissement naturel en ambiance tropicale de composites modèles époxy/verre : approche nanoscopique de l'étude des interphases". Electronic Thesis or Diss., Toulon, 2013. http://www.theses.fr/2013TOUL0007.
Texto completoA simplified glass fiber/epoxy composite was exposed to artificial ageing conditions (UV and Hygrothermal) and natural ageing (humid tropical climate). A wide range of physicochemical, mechanical and observation techniques (SEM, AFM) were used to clearly identify the structure, morphology and the main properties of the epoxy-amine network of the resin alone and composite in the initial state. A gradient in structure and properties was shown up in the first 200 microns of resin and composite plates surfaces thanks to the systematic characterization of sample layers of 20 microns thickness. It is attributed to an amine deficit during the sample elaboration process. In composite plates, DMA and AFM measurements have highlighted the existence of an interphase area around the fibers with a higher molecular mobility and a lower stiffness than the epoxy-amine network in the bulk resinThe same methodology was used to follow the materials evolution during artificial and natural ageing.The effects of UV and hygrothermal ageing were analyzed independently on the resin and on the composite in order to identify the chemical and physicochemical alterations of the matrix on one hand and of fiber/matrix interphases on the other hand. Photochemical ageing effects are mainly localized on materials surfaces, while the hygrothermal ageing affects mainly fiber/matrix interfaces in composite. In both cases simplified degradation mechanisms of epoxy-amine network are proposed.Finally, the characterization results after natural exposure allow us to establish correlations with artificial ageing. Predominant effects are identified and an acceleration factor is proposed
Pattee-Gravel, Victor. "L'impact sur le cerveau du vieillissement cognitivement sain". Master's thesis, Université Laval, 2020. http://hdl.handle.net/20.500.11794/66428.
Texto completoIn this memoir, we propose different models in order to predict the effect of aging on brain atrophy, computed from neuroimagery data. We begin with different statistical tests in order to chose between models and assert if different regions have significant asymmetry in their development. We then compute critical moments after which we predict that the measures of a region have significantly decreased. We use these critical moments to order the regions, as we suppose it’s a good indicator of fragility in aging. We finish by proposing a method of predicting the neurological age of an individual from it’s neuroimagery data.
Martre, Pierre. "Architecture hydraulique d'une talle de fétuque élévée (festuca arundinacea schreb. ) ; implications pour les relations entre la transpiration et l'expansion foliaire". Poitiers, 1999. http://www.theses.fr/1999POIT2347.
Texto completoHaddara, Hisham S. "Nouvelles méthodes de caractérisation et modèles physiques de vieillissement des transistors MOS submicroniques". Grenoble INPG, 1988. http://www.theses.fr/1988INPG0079.
Texto completoExartier, Raphaël. "Températures effectives et dynamique lente dans des systèmes modèles". Paris 6, 2001. http://www.theses.fr/2001PA066509.
Texto completoRattenbach, Revital. "Construction de modèles de surexpression du gène PCP4 : Etude de sa régulation et des effets de sa surexpression". Paris 5, 2006. http://www.theses.fr/2006PA05D042.
Texto completoTabellion, Aurore. "Effets vasculaires des espèces réactives de l'oxygène et de l'azote dans différents modèles physiopathologiques murins". Nancy, 2006. http://www.theses.fr/2006NAN12509.
Texto completoDantan, Etienne. "Modèles conjoints pour données longitudinales et données de survie incomplètes appliqués à l'étude du vieillissement cognitif". Thesis, Bordeaux 2, 2009. http://www.theses.fr/2009BOR21658/document.
Texto completoIn cognitive ageing study, older people are highly selected by a risk of death associated with poor cognitive performances. Modeling the natural history of cognitive decline is difficult in presence of incomplete longitudinal and survival data. Moreover, the non observed cognitive decline acceleration beginning before the dementia diagnosis is difficult to evaluate. Cognitive decline is highly heterogeneous, e.g. there are various patterns associated with different risks of survival event. The objective is to study joint models for incomplete longitudinal and survival data to describe the cognitive evolution in older people. Latent variable approaches were used to take into account the non-observed mechanisms, e.g. heterogeneity and decline acceleration. First, we compared two approaches to consider missing data in longitudinal data analysis. Second, we propose a joint model with a latent state to model cognitive evolution and its pre-dementia acceleration, dementia risk and death risk
Colas, Damien. "Le cycle veille-sommeil dans des modèles murins de vieillissement normal ou pathologique : hypothèse NO-ergique". Lyon 1, 2004. http://www.theses.fr/2004LYO10044.
Texto completoEdouard, Clément. "Vieillissement des batteries Li-ion de traction : des mécanismes vers le vieillissement accéléré". Thesis, Compiègne, 2015. http://www.theses.fr/2015COMP2221/document.
Texto completoDue to their high power and energy densities, Li-ion batteries are the leading systems for the new generations of electric vehicles, for which an optimum cell design, management and configuration is essential. Modeling provides tools to perform complex analysis of the performance of Li-ion batteries and reduces the amount of time spent on experimental testing. The aim of our research is to propose a physics-based model that can predict battery behavior and aging under various conditions during the entire lifespan. A simplified electrochemical and thermal model that can predict both physicochemical and aging behaviors of Li-ion batteries has been studied. A sensitivity analysis of all its physical parameters has been performed in order to find out their influence on the model outputs based on simulations under various conditions. The results gave hints on whether a parameter needs particular attention when measured or identified and on the conditions under which it is the most sensitive. A specific simulation profile has been designed for parameters involved in aging equations in order to determine their sensitivity. Finally, a step-wise method has been followed to limit the influence of parameter values when identifying sorne of them. This sensitivity analysis and the subsequent step-wise identification method show very good results, such as a better fitting of the experimental data with simulated cell voltage. Beyond advanced comprehension and prediction, this physical model opens new possibilities to define accelerated aging tests
Kieffer, Pascal. "Calcification de la paroi artérielle : modèles, conséquences et mécanismes". Nancy 1, 2000. http://www.theses.fr/2000NAN12011.
Texto completoVirgili, Jessica. "Caractérisation d'un modèle murin transgénique de la maladie d'Alzheimer et de vieillissement accéléré". Master's thesis, Université Laval, 2018. http://hdl.handle.net/20.500.11794/29574.
Texto completoAging is central to the pathogenesis of Alzheimer’s disease, the most common form of dementia during the elderly. The incidence of sporadic AD is low before 65 years old; it then doubles every 5 to 6 years to surpass 8 cases per 100 personyears after 85. To model AD, numerous transgenic mice have been produced and characterized in the last decades. It was found that mice overexpressing mutated forms of the human amyloid-β (Aβ) precursor protein (hAPP) develop Aβ deposits in their brain, along with quantifiable memory deficits. Since the diagnosis of AD is dependent upon the histological visualization of both Aβ plaques and tau-laden neurofibrillary tangles, Dr LaFerla’s group (University of California, Irvine, USA) has developed the triple-transgenic model (3xTg-AD) expressing three mutant transgenes: Aβ precursor protein (APPSwe), presenilin-1 (PS1M146V), and tauP301L. This mouse line progressively develops both Aβ and tau pathologies in AD-relevant brain regions as well as deficits in synaptic plasticity and cognitive performance. However, the 3xTg-AD mouse does not develop frank neuronal loss as found in AD brain. A likely simple explanation is that, within the lifespan of a mouse, AD-relevant aging factors do not have the time to be fully expressed. To that aim, we crossed senescence-accelerated prone 8 mice (SAMP8) with 3xTgAD mice to produce senescence-accelerated 3xTg-AD mice with the hope to generate a model closer to the human disease. Our results indicate that senescence acceleration amplifies memory deficits and several AD-related neuropathological features -particularly the amyloid pathology- in female 3xTg-AD mice. Overall, the present data suggest that the SAMP8/3xTg-AD mouse is a valuable model combining aging factors and AD neuropathology, but also evidence complex interactions between genetic backgrounds, aging- and sex-related factors.
Bracquemond, Cyril. "Modélisation stochastique du vieillissement en temps discret". Phd thesis, Grenoble INPG, 2001. http://tel.archives-ouvertes.fr/tel-00004670.
Texto completoTabellion, Aurore. "Effets vasculaires des espèces réactives de l'oxygène et de l'azote dans différents modèles physiopathologiques murins". Nancy 1, 2006. http://www.theses.fr/2006NAN10232.
Texto completoProust-Lima, Cecile. "Modèles mixtes à structure latente pour donnéeslongitudinales multivariées hétérogènes :application à l'étude du vieillissement cognitif etde la démence". Phd thesis, Université Victor Segalen - Bordeaux II, 2006. http://tel.archives-ouvertes.fr/tel-00192386.
Texto completoNguyen, Thi-Hoa-Tam. "Modèle d’endommagement des assemblages collés : identification et application à la description d’un essai de vieillissement accéléré". Paris Est, 2008. http://pastel.paristech.org/5199/01/manuscrit_final_NGUYEN.pdf.
Texto completoJuston, Maxime. "Suivi du vieillissement des batteries lithium embarquées, en usage ferroviaire". Thesis, Compiègne, 2021. http://www.theses.fr/2021COMP2596.
Texto completoThe classical electrical model of a cell considers it as a homogeneous whole With unique characteristics (resistance, capacitance). On the contrary, we consider that a cell can be subdivided into a certain number of volumes which are considered as homogeneous from the point of view of electrical properties. The modelling of a cell is then carried out by a set of electrical circuits, one per volume. Once this construction is completed, we seek to characterise each of the parameters of the electrical circuits by means of experimental measurements. A new method of determining the parameters for cells with a non-linear open circuit voltage is proposed, which makes possible to solve many of the difficulties encountered in our work and in previous ones. The variations of the parameters with temperature and current are also determined. A second determination, this time by optimization, allows to introduce a difference of the parameters values in order to model the heterogeneity. Experimental comparisons allow to validate the relevance of the heterogeneous model and its performances. The parameters modelling the heterogeneity are representative of the cell internals and the monitoring of these parameters during the life of the cell, and therefore its ageing, allows a diagnosis of the latter to be made. An application on a pack of two cells, one new and one artificially aged, allows a qualitative discrimination of the cells. This validates the potential of this representation as a diagnostic tool
Cugnet, Mikael Georges André. "Intégration du vieillissement à la gestion d'une batterie plomb automobile". Bordeaux 1, 2008. http://www.theses.fr/2008BOR13583.
Texto completoMainzer, Carine. "Implication de l’IGF-1R dans la différenciation épidermique et le vieillissement". Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10120/document.
Texto completoInsulin-like growth factor 1 receptor (IGF-1R) and its signaling pathway have been widely studied for their growth promoting role on many cell types and their implication in development. On skin, the IGF-1R function has been associated to basal proliferation and contributes to epidermal morphogenesis, but very little is known about its involvement on keratinocytes differentiation and the few studies existing depict contradictory results. IGF-1R activity is maximal during teenage and tend to decrease during aging. Aged skin depicts major thinning and defects in permeability of skin barrier. Our work consisted in clarifying IGF-1R role on epidermal differentiation process and emphasized a correlation between aging, loss of skin quality and IGF-1R activity. By building 2D and 3D aging like models with low IGF-1R activity, we confirmed IGF-1R mitogenic role on both basal and progenitor-like keratinocytes. We demonstrated that IGF-1R activity regulated keratinocytes differentiation by either enhancing or slowing down differentiation markers deposition. More importantly, we highlighted the importance of IGF-1R activity for keratinocytes adhesion on both laminin-332 and collagen I/IV coatings, implying possible interactions with α6 and β1 integrins. This relationship was further correlated on skin biopsies of young and aged donors. In a parallel study, we showed that IGF-1R could induce cell senescence under acute H2O2 stress. Taken together, IGF-1R is necessary for the epidermal differentiation process and protects epidermis from acute oxidative stress induced damages
Mainzer, Carine. "Implication de l'IGF-1R dans la différenciation épidermique et le vieillissement". Phd thesis, Université Claude Bernard - Lyon I, 2014. http://tel.archives-ouvertes.fr/tel-01064069.
Texto completoMagnani, Riccardo. "Sur la quantification des effets du vieillissement démographique : une approche intégrée de micro-macro-simulations". Cergy-Pontoise, 2006. http://biblioweb.u-cergy.fr/theses/06CERG0325.pdf.
Texto completoThe aim of this PhD thesis is to quantify the economic impacts of population ageing, in particular on the macroeconomic system and on the pension system, using a general equilibrium approach. The thesis is divided in two parts. The first one is made up by two chapters in which we analyse the Italian demographic phenomenon. In particular, the first chapter is devoted to the detailed description of the OLG model of the type Auerbach-Kotlikoff (1987) - with endogenous growth, human capital accumulation and immigration - and shows the effects of the pension system reforms introduced during the 90’s. In the second chapter, we analyse different reforms (the increase in the retirement age, immigration policies, and the reduction in pension benefits) that could be introduced in order to solve the long run financial problem of the Italian pension system. The second part of the thesis develops a new methodology allowing integrating macro general equilibrium models and microsimulation models, where individuals make discrete choices (work-leisure, type of profession, etc. ). This methodology is described in the third chapter. In the fourth chapter, we apply this methodology in order to analyse the effects of Canadian population ageing at the macro level and at the micro level, in particular on the evolution of the individual choices, of the income distribution, and of inequalities
Hilber, Pascal. "Conséquences d'une neurodégénérescence précoce du cortex cérébelleux sur le vieillissement chez la souris : utilisation d'un mutant neurologique, la souris Lurcher". Rouen, 1999. http://www.theses.fr/1999ROUES004.
Texto completoMokondjimobe, Etienne. "Hexosaminidase (HEX) et phosphatase alcaline (PAL) du cartilage articulaire de lapin et des chondrocytes en culture ; modifications au cours du vieillissement et de l'arthrose (modèles in-vivo et in-vitro)". Paris 5, 1990. http://www.theses.fr/1990PA05P607.
Texto completoJullien, Jean-Baptiste. "Etude de fiabilité et définition de modèles théoriques de vieillissement en très haute température pour des systèmes électronique et microélectronique". Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14604/document.
Texto completoThis work is performed in analysis and prediction areas of Multi-Chip Module package reliability. It presents a reliability study on wire bonding in high temperature environment from aging tests and experimental analyzes. Results permit to identify degradation mechanisms and evaluate temperature limits of these interconnections. It develops a study of the thermomechanical behavior of adhesive joints from mechanical characterization tests, accelerated aging tests and finite element simulations. These methods are used to assess the criticality of packages from the design phase
Proust-Lima, Cécile. "Modèles mixtes à structure latente pour données longitudinales multivariées hétérogènes : application à l'étude du vieillissement cognitif et de la démence". Bordeaux 2, 2006. http://www.theses.fr/2006BOR21373.
Texto completoThe aim of this work was to propose statistical models for longitudinal, heterogeneous and multivariate data in order to describe the cognitive evolution and its association with dementia in the elderly. A nonlinear model with a latent process was proposed in which latent cognitive evolution is described by a mixed model including a Brownian motion, and psychometric tests which measure cognition are linked to the latent cognitive process by nonlinear estimated transformations. We then extended this model to account for the heterogeneity of the cognitive declines. We proposed two nonlinear latent class models for describing the profiles of cognitive decline and their association with either the probability of dementia at a given time or the risk of dementia with time. In addition to the description of the cognitive declines associated with dementia, we proposed a tool for detecting a dementia according to cognitive evolution
Mekary-Sawaya, Souha. "Synthèse de quelques analogues du naftidrofuryl : premiers résultats sur les taux de mortalité de la gerbille après une ischémie cérébrale". Paris 11, 1990. http://www.theses.fr/1990PA114815.
Texto completoChan, Yone Claudia. "Modèle numérique de vieillissement de l'os trabéculaire considérant l'hyperminéralisation du tissu et le chargement mécanique". Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4731/document.
Texto completoOsteoporosis is characterized by a low bone mass density but also an alteration of mechanical properties. The clinical diagnostic is made from the measure of the bone mineral density (BMD) but this examen seems insufficient to quantify bone resistance. In this work, a numerical model of cancellous bone degradation, aging and mechanical adaptation is proposed. Based on hypermineralization, this model simulates the cancellous bone remodeling process over many years. This model allows to predict the behavior of cancellous adaptation in a mechanical low loading case for instance. Results are similar to clinicial tendancy
Holder-Espinasse, Muriel. "Vers la compréhension de la formation et du vieillissement du cartilage à partir de deux modèles : souris transgéniques et remplacement trachéal". Lille 2, 2006. http://www.theses.fr/2006LIL2S039.
Texto completoThe first part of my thesis concerns the Erg gene. Erg belongs to the Ets family encoding a class of transcription factors. In vivo expression of the Erg gene has been previously delineated. Throughout the murine embryogenesis, the Erg gene expression is precocious and transient, and predominates in mesodermal tissues including pre-cartilaginous. Erg expression in the cartilage is restricted to the early stages of differentiation. We performed further analyses to study the function of the Erg gene in vivo. We employed transgenic mice approach to induce an over-expression of the Erg protein in a model over-expressing a dominant-negative protein restricted to the ETS domain. The transgene construct was prepared under the control of a mouse colII1 specific promoter. We were able to identify clinical abnormalities by comparison with age-matched littermates. The mice over-expressing the dominant-negative protein gradually developed early-ageing associated phenotypes including hyperlordosis, hyperkyphosis and reduced mobility. Skeletal x-rays and osteodensitometry confirmed the clinical findings, showing osteopenia and arthritis. Histological studies at different stages were also performed. In parallel, we analysed embryonic chondrocytes cultures. In the second part, we present a collaborative work on a tracheal replacement model. When a tumour or a malformation occurs, all kinds of attempts with different tracheal substitutes have been performed and reported in the literature without success. An original solution has recently been proposed on a sheep model to allow large tracheal replacement with aortic graft. More than fifty sheep were operated with successful results. Histological examinations showed a progressive transformation of the aortic graft into a tissue with tracheal epithelium and newly formed rings of cartilage. These preliminary results were confirmed on a second animal model, the mini-pig, despite unexpected surgical difficulties. We have performed histological studies and followed genes expression by in situ hybridisation on the newly formed cartilage rings. To allow a better understanding of this cellular transformation, we have performed aortic allograft from male sheep to female sheep trachea, and from female mini-pigs to male mini-pigs. Indeed, we have used a PCR technique of the SRY gene to analyse the origin of the cellular transformation. We have searched the SRY gene amplification in the grafts, and suggested that the underlying mechanism could be a colonisation of the graft by the native trachea
Fonte, Coralie. "Effets de différents modèles de stress sur le développement lymphocytaire". Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0185/document.
Texto completoSpaceflight is a source of various stresses leading to the weakening of the immune system. The efficiency of this system relies, notably, on the diversity of antigen receptor repertoires present on B (BCR) and T (TCR) cells, allowing the recognition of a vast array of antigens. During this thesis, I studied the diversity of antigen receptors in three different animal models: the amphibian Pleurodeles waltl, the murine anti‐orthostatic suspension model (simulated microgravity) and the CUMS (for "Chronic Unpredictable Mild Socio‐environmental stressors") murine model involving exposure to chronic social and environmental stressors similar to those encountered during spaceflights. Analyses of P. waltl IgM and IgY heavy chain repertoires have shown that they are highly diverse, making this species a nice animal model for studying the effects of spaceflight on the humoral immune system. We have also shown that 21 days of anti‐orthostatic suspension decrease murine B lymphopoiesis and moderately affect IgM heavy chain repertoire diversity. These results were compared with those obtained with old mice to determine if anti‐orthostatic suspension induces an accelerated aging of the immune system. Although we noted interesting similarities between these two groups of mice, we found that the effect of aging on IgM repertoire is stronger than that of the anti‐orthostatic suspension, suggesting that anti‐orthostatic duration should be extended to increase the effects of this model on antibody repertoire. Finally, regarding the CUMS model, we have shown that, when applied during gestation it does not affect T lymphopoiesis in newborn mice but affects 25% of their TCRβ heavy chain repertoire. These results suggest that low‐intensity chronic socio‐environmental stressors may alter antigen recognition capabilities of the host
Mohajer, Sara. "Stratégies de charge rapide de batteries lithium-ion prenant en compte un modèle de vieillissement". Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0027.
Texto completoA physics-based battery model is developed for an accurate state-detection of batteries in the automotive industry. In order to use the model for the purpose of fast charging control an aging observer is designed and integrated to the battery model. In a subsequent step a robust fast charging control is introduced to design a controller able to deal with large parametric uncertainties of the battery model while achieving the fast charging target. Finally some simplifications in the battery model structure, in the optimization technique and in the definition of fast charging profiles are proposed and evaluated to make the whole model applicable for an onboard battery management system
Sarazin, Marianne. "Elaboration d'un score de vieillissement : propositions théoriques". Phd thesis, Université Jean Monnet - Saint-Etienne, 2013. http://tel.archives-ouvertes.fr/tel-00994941.
Texto completoFresquet, Nadine. "Analyse expérimentale des effets du vieillissement sur les capacités d'apprentissage et de mémoire à court terme chez la drosophile (Drosophila melanogaster)". Toulouse 3, 1994. http://www.theses.fr/1994TOU30131.
Texto completoBerthollet, Amandine. "Contribution à la modélisation du béton vis-à-vis du vieillissement et de la durabilité : interaction des déformations de fluage et du comportement non-linéaire du matériau". Lyon, INSA, 2003. http://theses.insa-lyon.fr/publication/2003ISAL0051/these.pdf.
Texto completoConcrete structures can be exhibit a growth of the cracking state during aging. This pathology is inherent in the mechanical interaction between creep strains and non-linear behavior of the material. To understand this process, both tertiary creep kinetic and cracking characteristics are studied considering both the rate effect affected the concrete behavior and, the intrinsic or minimal strength of the material which, is reached at low loading rate. This thesis proposes a modeling for this interaction by way of a viscoelastic - viscoplastic rheological law based on DUVAUT- LIONS schema. A viscoelasticity- plasticity coupling and the introduction of the intrinsic strength as a fundamental parameter, bring the key idea of the modeling. Then, compressive, tensile and bending experimental tests are compared with numerical results to validate the constitutive relations and prove the performance of the model to reproduce the tertiary creep kinetic and the time - dependant crack evolution
Maisonnette, Daniel. "Influences mécaniques et métallurgiques de procédés haute température sur un alliage d'aluminium 6061-T6". Lyon, INSA, 2010. http://theses.insa-lyon.fr/publication/2010ISAL0006/these.pdf.
Texto completoThe thesis work is part of the actions of early qualification of a pressure vessel in the RJH (Jules Horowitz Reactor). This vessel is made of aluminium alloy 6061-T6. This is an age hardening allow whose mechanical properties are closely related to the precipitation state in the material. Tensile tests were used to measure the evolution of the mechanical properties of the material previously subjected to thermal loading representative of an electron beam welding operation (EB welding). Tests were conducted at room temperature and at high temperature. Then metallurgical observations by small Angle Neutron Scattering (SANS) and by Transmission Electron Microscopy (TEM) gave the size and the volume fraction of precipitates. The results of these campaigns improved our understanding of the mechanical properties and evolution with thermal history. Furthermore, these experiments were used to develop a metallurgical model to forecast the characteristics of the precipitation state. A model was linked to a hardening model for the calculation of the yield strength of the material after various thermal loading. A phenomenological mechanical model was also developed to represent the behaviour of a structure subjected to thermal loading
Chaari, Ramzi. "Evaluation et modélisation du vieillissement des supercondensateurs pour des applications véhicules hybrides". Thesis, Bordeaux 1, 2013. http://www.theses.fr/2013BOR14828/document.
Texto completoThe integration of ultracapacitors in applications like hybrid requires knowledge of their behavior during aging. Thus, the objective of this thesis is the evaluation of aging and the definition of a model for predicting the health of supercapacitors. The aging results are presented focusing mainly on the evolution of performance during accelerated aging function of temperature, voltage and duration of stops in the case of cycling. An aging model is defined to describe the evolution of performance by focusing on the key mechanisms of aging
Jacquet, Marlyse. "Effets promnésiants de l'activation des récepteurs sérotoninergiques de type 4 (5-HT4) dans des modèles rongeurs (rats, souris) de vieillissement normal et pathologiques". Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM3070.
Texto completoIn normal aging or pathological brain diseases in rodents procedural memory is spared while reference memory is deeply impaired.Injection of a partial selective 5-HT4 agonist (SL65.0155. 0.01mg/kg) enabled complete recovery of association learning performance in an olfactory associative discrimination task, the olfactory tubing maze for exemple.Activation of 5-HT4 receptors by a selective agonist could be useful for the symptomatic treatment of memory dysfunctions related to pathological aging such as Alzheimer’disease
David-Bosc, Elodie. "Rôle de la Caspase-2 au cours des processus neurodégénératifs associés au vieillissement. Conception rationnelle d’inhibiteurs sélectifs et évaluation sur des modèles biologique". Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS173/document.
Texto completoCaspase-2 (CASP-2) is unique among Caspases since its involved in a plethora of physiological processes and in severe and chronic neurodegenerative processes. In this context, recent studies have indicated that CASP-2 is a potential therapeutic target for Alzheimer’s disease. It is therefore necessary to develop specific inhibitors which would constitute pharmacological tools to better understand the role of this protease in the physiology and pathology of the neuron. The current Caspases inhibitors are mostly tetra or pentapeptide sequences that reproduce the patterns preferentially recognized by these enzymes. During this thesis project, we used three identification strategies ; (i) a rational design approach of peptides targeting the active site, (ii) in silico design of peptides of the dimerization interface, (iii) rational an random screening of small organic molecules. Among these strategies, inhibition of the active site has been shown to be the most productive one. We have been able to demonstrate that the variation of the Alanine residue in P2 on the pattern VDVAD increased efficiency and selectivity parameters. Based on this observation, a serie of peptides “LJ” with various inhibitory mechanisms has been developed. Two compounds LJ2 and LJ3, demonstrated excellent inactivation and selectivity parameters toward CASP-2. In neuronal networks reconstructed in vitro, LJ2 and LJ3 protect against synapse loss. This thesis project opens the field to new perspectives on the functional level as well as on the therapeutic plan
David-Bosc, Elodie. "Rôle de la Caspase-2 au cours des processus neurodégénératifs associés au vieillissement. Conception rationnelle d’inhibiteurs sélectifs et évaluation sur des modèles biologique". Electronic Thesis or Diss., Sorbonne université, 2018. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2018SORUS173.pdf.
Texto completoCaspase-2 (CASP-2) is unique among Caspases since its involved in a plethora of physiological processes and in severe and chronic neurodegenerative processes. In this context, recent studies have indicated that CASP-2 is a potential therapeutic target for Alzheimer’s disease. It is therefore necessary to develop specific inhibitors which would constitute pharmacological tools to better understand the role of this protease in the physiology and pathology of the neuron. The current Caspases inhibitors are mostly tetra or pentapeptide sequences that reproduce the patterns preferentially recognized by these enzymes. During this thesis project, we used three identification strategies ; (i) a rational design approach of peptides targeting the active site, (ii) in silico design of peptides of the dimerization interface, (iii) rational an random screening of small organic molecules. Among these strategies, inhibition of the active site has been shown to be the most productive one. We have been able to demonstrate that the variation of the Alanine residue in P2 on the pattern VDVAD increased efficiency and selectivity parameters. Based on this observation, a serie of peptides “LJ” with various inhibitory mechanisms has been developed. Two compounds LJ2 and LJ3, demonstrated excellent inactivation and selectivity parameters toward CASP-2. In neuronal networks reconstructed in vitro, LJ2 and LJ3 protect against synapse loss. This thesis project opens the field to new perspectives on the functional level as well as on the therapeutic plan
Huber, Hélène. "Vieillissement, dépenses de santé et inégalités de recours aux soins : essais de micro-économétrie appliquée". Phd thesis, Université de Nanterre - Paris X, 2006. http://tel.archives-ouvertes.fr/tel-00181627.
Texto completoUn premier chapitre expose les méthodes économétriques employées lors de l'estimation d'équations explicatives de la consommation de
soins sur données individuelles.
Un deuxième chapitre développe une méthode originale visant à comparer les effets du vieillissement démographique à d'autres effets influençant la hausse des dépenses de santé entre les années 1992 et 2000. Nous montrons que la hausse des dépenses est principalement due aux changements de comportement face à la maladie, ces changements de comportements pouvant être en grande partie liés au progrès technique. Le vieillissement démographique n'a qu'un rôle mineur dans l'explication de la hausse des dépenses
de santé. De plus, nous montrons que l'état de santé moyen s'améliore.
Un troisième chapitre propose une méthode novatrice de décomposition des inégalités de consommation de soins par facteur. A morbidité donnée, la consommation de soins est concentrée chez les individus les plus riches de la distribution ; or nous montrons que cette inéquité est pour moitié due à l'hétérogénéité des comportements due à la position des individus dans l'échelle des revenus, cette hétérogénéité n'étant pas identifiable dans les décompositions standard. Trois applications sont proposées : la décomposition des inégalités par facteur pour la France en 1998, l'évaluation de l'impact de la CMU-C sur l'évolution des inégalités de consommation de soins, enfin la comparaison des sources d'inégalité entre les personnes âgées (65 ans et plus) et les autres.
Jobeili, Lara. "Évolution de modèles tridimensionnels de peau reconstruite pour approfondir la connaissance des mécanismes du vieillissement cutané et validation de l’efficacité « anti-âge » du sélénium". Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1044/document.
Texto completoSkin and its aging is a public health issue. In vitro skin models available for the study aging remain perfectible. In this context, our objectives were simultaneously to use skin equivalent (SE) developed in our laboratory i) to better understand mechanisms of skin aging, ii) to demonstrate the effectiveness of selenium as “anti-aging” and finally iii) to improve SE using the porous or scaffold free model with fibroblasts from the same donor at different ages. Thus, the model of SE mimicking senescence showed an overexpression of microRNA miR30-a by RT qPCR in old SE with an alteration of the barrier function measured by the transepidermal water loss and a deficiency of epidermal terminal differentiation (decreased expression of loricrin and involucrin). With the same SE model, our results demonstrate that selenium supplementation delays the senescence of keratinocytes stem cells. This effectiveness does not involve antioxidant effect as expected but the activation of their adhesion to the basement membrane, which participates in preserving stemness and epidermal renewal. Finally, we had the opportunity to prepare SE with fibroblasts from a single donor at 36 and 72 years old. The histological results show that age induces an increase in the expression of elastin and fibrillin as well as their co-expression. The increase of LTBP1 and aSMA suggests that this unexpected increase is due to deregulation of the TGF-ß pathway and fibroblasts differentiation into myofibroblasts. In conclusion, the use of different models of SE helps us to explore some mechanisms leading to skin aging and to demonstrate the efficacy of selenium as “anti-aging”
Sivera, Raphaël. "Modélisation et mesure de l'évolution morphologique du cerveau à partir d'IRM structurelles pour l'étude des maladies neurodégénératives". Thesis, Université Côte d'Azur (ComUE), 2019. http://www.theses.fr/2019AZUR4082.
Texto completoIn medical imaging, the statistical analysis of deformations enables the characterization of the effects of neurodegenerative diseases on the brain morphology. Deformations are able to capture precise changes but their analysis raises specific methodological challenges and the results may be difficult to interpret. The objective of this thesis is to present deformation-based methods and to show applications that contribute towards a better clinical interpretation of morphological changes. In the first part, we introduce a joint model of the effects of normal aging and Alzheimer’s disease on the brain morphology. The model proposes a simple description of both processes and is used to generate realistic and personalized evolutions under several diagnosis conditions. In the second part, a morphometric study is conducted on the MAPT cohort. We bring out an effect of the multidomain intervention on the longitudinal deformation of the brain using multivariate statistics. This effect is not observable using clinical assessments or volumetric measures, but we show that the differences associated with the treatment are correlated with better cognitive performance. The third part extends the statistical methodology used in the second part. A complete hypothesis testing framework for multivariate images is presented. It generalizes existing non-parametric frameworks and requires few hypothesis on the data to be applied. Finally the last part builds on the methodology of the previous sections to explore the relation between morphology and cognition in elderly subjects. The spatial correlations and the patterns of evolution described in this section suggest the existence of several dynamics of evolutions that are associated with specific cognitive changes
Bouvet, Geoffrey. "Relations entre microstructure et propriétés physico-chimiques et mécaniques de revêtements époxy modèles". Thesis, La Rochelle, 2014. http://www.theses.fr/2014LAROS039/document.
Texto completoThis work highlights the microstructure-properties relations inside representative epoxy based model coatings for anticorrosion paints. These relations have been established for the initial state as well as the hygrothermal ageing. First, we characterised physico-chemical and mechanical properties of the totally crosslinked DGEBA/DAMP stoichiometric system. These properties have been compared to the DGEBA/TETA system and they showed the strong influence of the microstructure on these initial properties. Cyclic hygrothermal ageing have been completed at different temperatures on free films, in order to measure the impact of the microstructure on the durability of epoxy systems. This work has shown the influence of the water-polymer interactions on diffusion phenomena. Moreover, the evolutions of several physico-chemical and mechanical properties have been characterised using DMA (submersible clamps), during different sorption-desorption steps. A pseudo-fickian behaviour has been evidenced during the first sorption, and it was followed by a fickian behaviour for all other steps. The inherent causes of this evolution have been proposed, by considering microstructural reorganisations of the studied epoxy systems. Other hygrothermal ageing have been carried out using EIS on coatings, in order to study the effects of the coating/steel substrate interface on diffusion phenomena, especially the role of residual stresses. We finally studied the influence of the visco-elastic stress on the coating water intake phenomena
Giannarelli, Sylvie. "Validation de modèles cellulaires issus du tractus digestif : la lignée IEC-6 pour l'étude de l'adaptation aux AINS et à l'éthanol au cours des passages successifs : mise au point d'un modèle de cellules musculaires lisses isolées". Aix-Marseille 3, 1996. http://www.theses.fr/1996AIX30015.
Texto completoRichaud, Myriam. "Modèles intégrés de mécanistique et de résistance en oncopharmacologie-sénescence : Caenorhabditis elegans et Hypsibius dujardini". Thesis, Montpellier, 2016. http://www.theses.fr/2016MONT3517/document.
Texto completoBiological models are necessary to understand how organisms works, how evolution of living run, to test new treatments or to perform toxicological assessments as well. Cellular culture is one of the methods employed because it is easy to use. However, working on isolated cells doesn’t always allow to challenge of the results with more complex conditions as found in full organisms. Biologist needs to develop new biological models for new assessments but the new model choice can be a problem. Murine model, frog, drosophila, yeast, zebrafish,… have each other some benefits and limits. Their choice is directly linked with their use and with the type of research we intend to make.The aim of our work was to develop biological models to oncopharmacology and aging studies.The nematode model with Caenorhabditis elegans was used in several projects. One study was made on gases. They were tested in terms of toxicity, mutagenicity and cancerogenicity. On the other hand, a new tool was developed for prospective studies on either toxicology or mechanistic with the mitochondrial respiration measure with the Seahorse XF24 Analyzer device.The second biological model studied is the tardigrade and more exactly Hypsibius dujardini. Tardigrades are extremely resistant organisms to harshest conditions. They can resist to desiccation. To gain insights on tardigrade resistance, we have choice to analyze the mitochondrial dynamics in the course of anhydrobiosis exit by using mitochondrial dyes and respiration measurements
Urani, Alexandre. "Effets des agonistes du récepteur [sigma]1 (sigma1) dans un modèle animal de dépression. Interaction avec les neurostéroi͏̈des". Montpellier 2, 2001. http://www.theses.fr/2001MON20220.
Texto completoLe, Cunff Yann. "Aging : between evolution and demography". Paris 7, 2012. http://www.theses.fr/2012PA077259.
Texto completoAging is a complex, multiscale issue, at the interface between evolution and demography. The disposable soma theory, an evolutionary theory of aging, proposes that trade-offs between maintenance and reproduction drive aging. Despite its success at describing similarities in aging at the individual level, the disposable soma theory does not provide insights about mortality patterns observed across species. By contrast, biodemographic studies of aging show that population heterogeneity explains these mortality patterns. Yet, they do not address whether population heterogeneity derives from evolutionary processes. In this PhD thesis, I propose to bridge these gaps in five steps. First, I tackle the evolution of biological networks to show that natural selection leads to increased robustness to perturbations. Second, I introduce costs for reproduction in this model : individual robustness now co-evolves with population stability. Third, damage is allowed to accumulate over age. Each individual has its own resource allocation strategy between maintenance and reproduction. The distribution of strategies in the population evolves over generations in response to environmental constraints: evolved populations display mortality patterns which reproduce those of yeast, worms, flies and humans. Fourth, the model predicts population heterogeneity for different forms of trade-offs and different stress conditions. Fifth, an evolutionary framework is proposed to account for the evolution of heterogeneity: any heritable information should be described as a distribution of possible phenotypes. The effect of natural selection orly consists in shaping this distribution
Léger, Romain. "Contribution à l'étude de la durabilité des structures collées soumises à des efforts mécaniques après vieillissement humide". Phd thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aéronautique, 2010. http://tel.archives-ouvertes.fr/tel-00518367.
Texto completoGeorgeon, Chartier Carole. "Evaluation des effets du vieillissement sur la signalisation calcique des cellules musculaires lisses des artères cérébrales dans les modèles murins C57BL6/J, SAMR1 et SAMP8 dans des conditions normales et sous restriction calorique". Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14692/document.
Texto completoDuring aging, cerebral arteries undergo structural and functional changes, particularly in smooth muscle cells (SMC). SMC is responsible for maintaining vascular reactivity via calcium signaling involving different actors and can regulate two phenomena: contraction and relaxation. These actors regroup channels (CCVD, RYR, IP3R) calcium pumps (SERCA, PMCA, NCX, STIM / ORAI) and their regulators (PLB, FKBP12.6, TRPP2, SARAF, TRIC). Caloric restriction (CR) appears as a factor in delaying aging and its pathologies. Our work is strongly involved in the study of calcium signaling in SMC, focusing on genomic and functional alterations during aging of cerebral arteries in mice C57BL6/J. We were able to demonstrate an altered calcium signaling, which is partly through modulation of gene and protein expression levels of calcium channels and pumps involved in this phenomenon, and a functional change in terms of calcium signals and contraction. After 5 months under RC, it was highlighted a slow calcium signaling alterations associated with aging and a decrease of SMC oxidation by SAMP8