L’autophagie est une voie catabolique durant laquelle des constituants cytoplasmiques sont engloutis dans des vésicules à double membrane nommées autophagosomes. Elle sert à éliminer les protéines mal repliées ou les agrégats protéiques, à détruire les organites défectueux comme les mitochondries, le réticulum endoplasmique et les peroxysomes mais aussi des pathogènes intracellulaires. Le matériel séquestré dans les autophagosomes est ensuite envoyé, pour dégradation, vers le lysosome. La dégradation du matériel séquestré génère des nucléotides, des acides aminés et des acides gras qui seront recyclés en vue de la synthèse de macromolécules et de la génération d’ATP.Dans cette étude nous explorons l’aspect cellulaire et fonctionnel de la voie de l’autophagie chez Caenorhabditis elegans. Nous montrons que le génome du nématode contient deux homologues du gène autophagique de levure Atg8. Ces homologues codent pour les protéines LGG-1 et LGG-2 qui sont des protéines des membranes des autophagosomes. Ces protéines agissent de façon synergique dans les processus physiologiques impliquant l’autophagie, en l’occurrence, la longévité et la formation des larves dauer.Nous montrons également que l’autophagie est impliquée dans le maintien de l’homéostasie cellulaire chez les mutants ESCRT. Les complexes ESCRT sont impliqués dans l’adressage des protéines ubiquitinées vers les corps multi vésiculaires pour les dégrader. Les mutants ESCRT se caractérisent par des altérations cellulaires et développementales. Nos résultats indiquent que l’inactivation des ESCRT cause une augmentation du flux autophagique. L’inactivation de l’autophagie dans ces mutants exacerbe les défauts cellulaires alors que son induction protège de la dégradation. / Macroautophgagy is a catabolic process involved in the clearance of cellular components in the lysosome when cells face starvation conditions. This eukaryotic process requires the formation of double membrane vesicles named autophagosomes. Autophagy is implicated in the elimination of misfolded proteins, protein aggregates and long-lived or damaged organelles such as mitochondria, endoplasmic reticulum and peroxysomes. It is alos required for the clearance of intracellular pathogens. The material enclosed inside autophagososmes in degraded in the lysosome: nucleotides, amino-acids and fatty-acids are generated and reused for neosynthesis of macromolecules and ATP.In the present study, we are exploring the cellular and functional aspects of the autophagic pathway in Caenorhabditis elegans. We show that the genome of the worm contain two homologues of the Yeast autophagic gene, Atg8. These homlogues encode for two proteins namely, LGG-1 and LGG-2, which localize to the autophagosomal membranes. We have shown that this two proteins act synergistically in dauer formation and longevity.We have also shown that autophagy play an important role in maintaining cell homeostasis in endosomal maturation mutans. These latter mutants show defects in the ESCRT coplexes (Endosomal Sorting Complex Required for Transport). ESCRT complexes are required the recycling of cell surface receptors and for the sorting of ubiquitinated prtoteins into the multivesicular bodies. Mutations in the ESCRTs cause cellular et developmental defects. In our study, we show that autophagy is induced in these mutants and play a beneficial role in correcting cellular defects.

This thesis deals with classification of different types of time courses of ECG signals. Main objective was to recognize the normal cycles and several forms of arrhythmia and to classify the exact types of them. Classification has been done with usage of algorithms of Neural Networks in Matlab program, with its add-on (Neural Network Toolbox). The result of this thesis is application, which makes possible to load an ECG signal, pre-process it and classify its each cycle into five classes. Percentage results of this classification are in the conclusion of this thesis.

This thesis describes the design, manufacture and characterisation of thick vacuum plasma sprayed tungsten (W) coatings on steel substrates. Fusion is a potentially clean, sustainable, energy source in which nuclear energy is generated via the release of internal energy from nuclei. In order to fuse nuclei the Coulomb barrier must be breached - requiring extreme temperatures or pressures – akin to creating a ‘star in a box’. Tungsten is a promising candidate material for future fusion reactors due to a high sputtering threshold and melting temperature. However, the large coefficient of thermal expansion mismatch with reactor structural steels such as the low activation steel Eurofer’97 is a major manufacturing and in-service problem. A vacuum plasma spraying approach for the manufacture of tungsten and tungsten/steel graded coatings has been developed successfully. The use of graded coatings and highly textured 3D interface surfi-sculpt substrates has been investigated to allow the deposition of thick plasma sprayed tungsten coatings on steel substrates. Finite element models have been developed to understand the residual stresses that develop in W/steel systems and made use of experimental measurements of coating thermal history during manufacture and elastic moduli measured by nano-indentation. For both the graded and surfi-sculpt coating, the models have been used to understand the mechanism of residual stress redistribution and relief in comparison with simple W on steel coatings, particularly by consideration of stored strain energy. In the case of surfi-sculpt W coatings, the patterned substrate gave rise to regular stress concentrating features, and allowed 2mm thick W coatings to be produced reproducibly without delamination. Preliminary through thickness residual stress measurements were compared to model predictions and provided tentative evidence of significant W coating stress relief by regulated coating segmentation.