Estudo de delineamento transversal com objetivo de analisar carga de trabalho, risco para estresse psicossocial e a resiliência nos profissionais da Enfermagem que cuidam de adultos portadores de GMR em um hospital universitário. O local do estudo foi uma unidade de internação do Hospital de Clínicas de Porto Alegre. A carga de trabalho foi avaliada através da coleta dos dados do prontuário eletrônico de 80 pacientes, no período de agosto a dezembro de 2012. Foram utilizados os instrumentos do Sistema de Classificação de Pacientes(SCP) de Perroca e do Nursing Activities Score(NAS). O estresse psicossocial e a resiliência foram avaliados em 39 profissionais da enfermagem através das escalas Desequilíbrio Esforço-recompensa e Escore de Resiliência. Os dados foram analisados por meio de estatística descritiva e analítica, com utilização do software SPSS 18.0. Conforme o SCP de Perroca, a classificação quanto à necessidade de cuidados do paciente resultou em 18 (22,5%) pacientes com cuidados Intermediários, 35 (43,7%) semiintensivos e 27 (33,8%) intensivos (p< 0,001). O tempo médio para cuidado aferido por meio da NAS foi de 12 ± 4 horas em 24 horas, por paciente (49,9 ± 14,9 pontos). O risco para estresse psicossocial foi constatado em 69,23% (27) da amostra e a média do escore de resiliência foi 132 ± 15,94 pontos. Os resultados demonstram profissionais expostos à alta carga de trabalho em situação de risco e vulnerabilidade para estresse psicossocial. Sugere-se revisar quadro de pessoal e organização do trabalho, bem como implementar programas para reforço de estratégias de enfrentamento dos níveis de estresse no trabalho. / Cross-sectional study aimed to analyze workload, psychosocial stress risk and resilience score in nursing professionals who care for adults with multidrug-resistant organisms a university hospital. The study site was in a inpatient unit of the Hospital de Clinicas de Porto Alegre. For a description of the workload data were collected from the electronic medical records of 80 patients in the period from August to December 2012, totaling 674 records and tools were used System Patient Classification Perroca and Nursing Activities Score. Instruments from the System Patient Classification of Perroca and from Nursing Activities Score were used. The psychosocial stress and resilience were assessed in 39 nursing professionals through questionnaires Effort-reward imbalance and Resilience score. Data were analyzed using descriptive and analytical statistics, using the SPSS 18.0 software. As the SCP of Perroca, ranking as the need for patient care resulted in 18 (22.5%) patients with Intermediate Care, 35 (43.7%), semi-intensive and 27 (33.8%) intensive (p <0.001). The average time for care to these patients identified by the NAS was 49.9 ± 14.9 points. The risk for psychosocial stress was observed in 69,23% (27) of the sample and the average score was 132 ± 15.94 Resilience points. The results indicated workers exposed to high workload at risk and vulnerability to psychosocial stress. It is suggested to review workload and organize programs aimed at strengthening strategies for dealing with stress levels at work. / Estudio transversal tuvo como objetivo analizar la carga de trabajo, riesgo para estrés psicosocial y la puntuación de resiliencia de los profesionales de Enfermería que atienden a adultos con GMR en un hospital universitario. El sitio de estudio fue un unidad de internación, del Hospital de Clínicas de Porto Alegre. Para una descripción de la carga de trabajo, fueran colectados datos del prontuario electrónico de 80 pacientes en el período de agosto hasta diciembre de 2012 y herramientas se utilizaron del Sistema de Classificação de Pacientes (SCP) de Perroca y del Nursing Activities Score (NAS). El estrés psicosocial y la resiliencia fueran evaluados en 39 profesionales de enfermería usando los cuestionarios Desequilibrio Esforço- Recompensa y Escore de Resistencia. Los datos fueran analizados utilizando estadística descriptiva y analítica, con utilización del software SPSS 18.0. De acuerdo con el SCP de Perroca, la necesidad de la atención al paciente resueltó en 18 (22,5%) pacientes con cuidados intermedios, en 35 (43,7%) casi-intensivos y 27 (33,8%) intensivos (p<0,001). El tiempo medio para cuidado con los pacientes identificados por NAS fue de 49,9 ± 14,9 puntos. El riesgo para el estrés psicosocial fue constatado en 69,23% (27) de la muestra y la media del escore de resiliencia fue 132±15,94 puntos. Resultado indicaran profesionales expuestos a la alta carga de trabajo en situaciones de riesgo y vulnerabilidad para estrés psicosocial. Se sugiere revisar la carga de trabajo y organizar programas visando refuerzo de estrategia para tratar con los niveles de estrés en el trabajo.

Estudo de delineamento transversal com objetivo de analisar carga de trabalho, risco para estresse psicossocial e a resiliência nos profissionais da Enfermagem que cuidam de adultos portadores de GMR em um hospital universitário. O local do estudo foi uma unidade de internação do Hospital de Clínicas de Porto Alegre. A carga de trabalho foi avaliada através da coleta dos dados do prontuário eletrônico de 80 pacientes, no período de agosto a dezembro de 2012. Foram utilizados os instrumentos do Sistema de Classificação de Pacientes(SCP) de Perroca e do Nursing Activities Score(NAS). O estresse psicossocial e a resiliência foram avaliados em 39 profissionais da enfermagem através das escalas Desequilíbrio Esforço-recompensa e Escore de Resiliência. Os dados foram analisados por meio de estatística descritiva e analítica, com utilização do software SPSS 18.0. Conforme o SCP de Perroca, a classificação quanto à necessidade de cuidados do paciente resultou em 18 (22,5%) pacientes com cuidados Intermediários, 35 (43,7%) semiintensivos e 27 (33,8%) intensivos (p< 0,001). O tempo médio para cuidado aferido por meio da NAS foi de 12 ± 4 horas em 24 horas, por paciente (49,9 ± 14,9 pontos). O risco para estresse psicossocial foi constatado em 69,23% (27) da amostra e a média do escore de resiliência foi 132 ± 15,94 pontos. Os resultados demonstram profissionais expostos à alta carga de trabalho em situação de risco e vulnerabilidade para estresse psicossocial. Sugere-se revisar quadro de pessoal e organização do trabalho, bem como implementar programas para reforço de estratégias de enfrentamento dos níveis de estresse no trabalho. / Cross-sectional study aimed to analyze workload, psychosocial stress risk and resilience score in nursing professionals who care for adults with multidrug-resistant organisms a university hospital. The study site was in a inpatient unit of the Hospital de Clinicas de Porto Alegre. For a description of the workload data were collected from the electronic medical records of 80 patients in the period from August to December 2012, totaling 674 records and tools were used System Patient Classification Perroca and Nursing Activities Score. Instruments from the System Patient Classification of Perroca and from Nursing Activities Score were used. The psychosocial stress and resilience were assessed in 39 nursing professionals through questionnaires Effort-reward imbalance and Resilience score. Data were analyzed using descriptive and analytical statistics, using the SPSS 18.0 software. As the SCP of Perroca, ranking as the need for patient care resulted in 18 (22.5%) patients with Intermediate Care, 35 (43.7%), semi-intensive and 27 (33.8%) intensive (p <0.001). The average time for care to these patients identified by the NAS was 49.9 ± 14.9 points. The risk for psychosocial stress was observed in 69,23% (27) of the sample and the average score was 132 ± 15.94 Resilience points. The results indicated workers exposed to high workload at risk and vulnerability to psychosocial stress. It is suggested to review workload and organize programs aimed at strengthening strategies for dealing with stress levels at work. / Estudio transversal tuvo como objetivo analizar la carga de trabajo, riesgo para estrés psicosocial y la puntuación de resiliencia de los profesionales de Enfermería que atienden a adultos con GMR en un hospital universitario. El sitio de estudio fue un unidad de internación, del Hospital de Clínicas de Porto Alegre. Para una descripción de la carga de trabajo, fueran colectados datos del prontuario electrónico de 80 pacientes en el período de agosto hasta diciembre de 2012 y herramientas se utilizaron del Sistema de Classificação de Pacientes (SCP) de Perroca y del Nursing Activities Score (NAS). El estrés psicosocial y la resiliencia fueran evaluados en 39 profesionales de enfermería usando los cuestionarios Desequilibrio Esforço- Recompensa y Escore de Resistencia. Los datos fueran analizados utilizando estadística descriptiva y analítica, con utilización del software SPSS 18.0. De acuerdo con el SCP de Perroca, la necesidad de la atención al paciente resueltó en 18 (22,5%) pacientes con cuidados intermedios, en 35 (43,7%) casi-intensivos y 27 (33,8%) intensivos (p<0,001). El tiempo medio para cuidado con los pacientes identificados por NAS fue de 49,9 ± 14,9 puntos. El riesgo para el estrés psicosocial fue constatado en 69,23% (27) de la muestra y la media del escore de resiliencia fue 132±15,94 puntos. Resultado indicaran profesionales expuestos a la alta carga de trabajo en situaciones de riesgo y vulnerabilidad para estrés psicosocial. Se sugiere revisar la carga de trabajo y organizar programas visando refuerzo de estrategia para tratar con los niveles de estrés en el trabajo.

Dans cette étude, nous analysons les conséquences mécaniques des transformations de phase diffusives, particulièrement la plasticité de transformation ou TRIP (TRansformation Induced Plasticity) ainsi que le comportement élasto-viscoplastique. Cette plasticité de transformation, explicable par le mécanisme de Greenwood-Johnson, est souvent décrite avec le modèle de Leblond qui fait l'hypothèse d'un comportement élastoplastique. Dans ce modèle comme dans la majorité des analyses expérimentales et des modélisations (analytiques, par éléments finis, FFT ou encore champ de phase), une des hypothèses principales est de ne pas prendre en compte le caractère visqueux du comportement. Or plusieurs études récentes montrent que le comportement des deux phases (parente et produite) peut être très sensible au taux de déformation imposé, particulièrement à haute température. D'où l'intérêt de développer une modélisation rendant compte des effets visqueux présents lors de certaines transformations. Pour ce faire, nous adoptons une modélisation numérique où le comportement de chaque phase est décrit par une loi élasto-viscoplastique à écrouissage mixte associée à la loi de Norton ; la cinétique de transformation est imposée et le problème d'interactions mécaniques entre phases est traité par la méthode des éléments finis. D'une part, la contribution de la viscosité au TRIP est quantifiée pour différents taux de déformation imposés durant la transformation de phase. D'autre part, l'effet du taux de transformation (configuration arbitraire) sur la prédiction du TRIP est évalué et caractérisé. Une extension des modèles existants (à cinétique périodique et aléatoire) est proposée. Elle consiste d'abord à étudier et évaluer l'effet de la morphologie de germe ainsi que l'anisotropie de croissance sur la prédiction du TRIP. Ensuite, une amélioration avec un modèle anisotherme, basé sur des mesures expérimentales existantes, a été introduite. Elle consiste principalement à tenir compte de la variation des propriétés mécaniques en fonction de la température. Les analyses montrent que la prise en compte de la viscosité peut conduire à des effets importants sur la prédiction du TRIP par rapport aux résultats obtenus avec un modèle élastoplastique classique. Elles montrent en particulier, en configuration anisotherme, une amélioration de la prédiction du TRIP mesuré expérimentalement lors de la transformation perlitique d'un acier 100Cr6 [Tahimi, 2012]. Cette étude permet par ailleurs de dégager des tendances évidentes dans les relations entre le TRIP et l'histoire de la transformation : chargement mécanique et cinétique de transformation, morphologie des germes et anisotropie de croissance. Ces résultats pourront contribuer à l'élaboration d'un modèle analytique simple prenant en compte la viscosité. / In this study, the mechanical consequences of phase transformations in steel, particularly, the TRansformation Induced Plasticity TRIP as well as the elasto-viscoplastic behavior has been analyzed. This transformation plasticity, due to the Greenwood-Johnson mechanism, is often described with the model of Leblond with the assumption of an elastoplastic behavior. Moreover, in the majority of experimental analysis or numerical finite elements modeling FEM or phase field modeling PFM, the viscous criteria were not considered. However, several recent studies have demonstrated that both phases (parent and product) show high strain-rate sensitivity at elevated temperatures. Hence, the principal interests using the FEM modeling to extend these main reference models of [Leblond, 89] and [Taleb-Sidoroff, 2003], with taking into account the viscous effects, which are present during some phase transformations, especially at high temperatures. To do this, the behavior of each phase is described by an elasto-viscoplastic law with mixed hardening associated to the Norton law. The transformation kinetics is imposed and the problem of mechanical interactions between phases is processed by the finite element method. On the one hand, the contribution from viscosity to TRIP was quantified for different strain-rate during phase transformation. On the other hand, the effect of an arbitrarily-set of transformation-rate in the FEM simulations was evaluated and characterized. An extension of the existing models (for periodic and random kinetics) is proposed. It consists at first in studying and in evaluating the effect of both the morphology of nuclei and the growth anisotropy, on the prediction of TRIP. Then, an improvement with non-isothermal model, based on existing experimental measures, was introduced. It consists mainly in taking into account the variation of the mechanical properties of the mixture of both phases, according to the temperature. The predictions show that in such cases, the consideration of the viscosity can lead to major changes of the estimated TRIP compared with results obtained from a classic plastic model. Also, the prediction of TRIP can be significantly influenced by the choice of the morphology of germs and by the type of growth: isotropic or anisotropic. These improvements, particularly with the non-isothermal configuration, show a good agreement with experimental measures of TRIP on the 10006 steel during pearlite phase transformation [Tahimi, 2012]. This study allows besides, releasing obvious trends in the relations between the TRIP and the history of the phase transformation: mechanical loading and kinetics of transformation, morphology of nuclei and growth anisotropy. These results can contribute to the elaboration of a simple analytical model taking into account the viscous criteria.

Cette thèse est une étude de modèles d'image aléatoires avec des applications en synthèse de texture.Dans la première partie de la thèse, des algorithmes de synthèse de texture basés sur le modèle shot noise sont développés. Dans le cadre discret, deux processus aléatoires, à savoir le shot noise discret asymptotique et le bruit à phase aléatoire, sont étudiés. On élabore ensuite un algorithme rapide de synthèse de texture basé sur ces processus. De nombreuses expériences démontrent que cet algorithme permet de reproduire une certaine classe de textures naturelles que l'on nomme micro-textures. Dans le cadre continu, la convergence gaussienne des modèles shot noise est étudiée d'avantage et de nouvelles bornes pour la vitesse de cette convergence sont établies. Enfin, on présente un nouvel algorithme de synthèse de texture procédurale par l'exemple basé sur le récent modèle Gabor noise. Cet algorithme permet de calculer automatiquement un modèle procédural représentant des micro-textures naturelles.La deuxième partie de la thèse est consacrée à l'étude du processus feuilles mortes transparentes (FMT), un nouveau modèle germes-grains obtenu en superposant des objets semi-transparents. Le résultat principal de cette partie montre que, lorsque la transparence des objets varie, le processus FMT fournit une famille de modèles variant du modèle feuilles mortes à un champ gaussien. Dans la troisième partie de la thèse, les champs aléatoires à variation bornés sont étudiés et on établit des résultats généraux sur le calcul de la variation totale moyenne de ces champs. En particulier, ces résultats généraux permettent de calculer le périmètre moyen des ensembles aléatoires et de calculer explicitement la variation totale moyenne des modèles germes-grains classiques. / This thesis is a study of stochastic image models with applications to texture synthesis. Most of the stochastic texture models under investigation are germ-grain models. In the first part of the thesis, texture synthesis algorithms relying on the shot noise model are developed. In the discrete framework, two different random processes, namely the asymptotic discrete spot noise and the random phase noise, are theoretically and experimentally studied. A fast texture synthesis algorithm relying on these random processes is then elaborated. Numerous results demonstrate that the algorithm is able to reproduce a class of real-world textures which we call micro-textures. In the continuous framework, the Gaussian convergence of shot noise models is further studied and new bounds for the rate of this convergence are established. Finally, a new algorithm for procedural texture synthesis from example relying on the recent Gabor noise model is presented. This new algorithm permits to automatically compute procedural models for real-world micro-textures. The second part of the thesis is devoted to the introduction and study of the transparent dead leaves (TDL) process, a new germ-grain model obtained by superimposing semi-transparent objects. The main result of this part shows that, when varying the transparency of the objects, the TDL process provides a family of models varying from the dead leaves model to a Gaussian random field. In the third part of the thesis, general results on random fields with bounded variation are established with an emphasis on the computation of the mean total variation of random fields. As particular cases of interest, these general results permit the computation of the mean perimeter of random sets and of the mean total variation of classical germ-grain models.

Cette thèse concerne une nouvelle méthode chimique de croissance par germes qui peut produire des assemblés de nanostructures métalliques epitaxiées sur des surfaces macroscopiques cristallines qui agissent comme germes. Cette approche permet d’obtenir des assemblés bien organisées en échelle centimétrique de nanofils métalliques de Co, qui sontmonocristallins, monodisperses de diamètres inferieurs à 10nm et qui ont une orientation perpendiculaire. Ils ont une anisotropie magnétique perpendiculaire et sont intéressantes pour des applications d’enregistrement magnétique à très haute densité. L’extension de cette méthode au fer donne des films nanostructurés de fer. L’orientation des nanostructures sur le support solide dépend de l’orientation cristallographique du substrat, alors que leur morphologie est dictée par la composition de la solution. Cet objectif a été atteint grâce à des études parallèles sur le mécanisme de croissance de nano-cristaux de cobalt en solution qui ont révélées une influence inattendue de la procédure de préparation de la solution mère sur la morphologie des nanocristaux. En plus,l’utilisation des germes nanoscopiques pour la croissance de Co et de Fe a rendu des nanofils longs de Co et des altères de Co-Fe et elle a contribué à la définition et l’amélioration des conditions expérimentales pour la croissance par germes de Co et de Fe sur les substrats solides. / This thesis concerns a new wet chemical seeded growth method that can produce arrays of metal nanostructures epitaxially grown on crystalline macroscopic surfaces which act as seeds. This approach produces wafer-scale organized 2D hexagonal arrays of perpendicularly oriented, monodisperse and monocrystalline metallic Co nanowires with diameters below 10 nm which exhibit perpendicular magnetic anisotropy and are interesting for applications in ultra high density magnetic recording. Extension of this approach to iron gives rise to nanostructured iron films. The orientation of the nanostructures on the solid substrate depends on the substrate crystallographic orientation, whereas their morphology is dictated by the solution composition. This objective was attained through parallel studies on the growth mechanism of cobalt nano-crystals in solution which revealed an unexpected influence of the stock solution preparation procedure on the nanocrystal morphology. In addition, the use of nanoscopicseeds for the overgrowth of cobalt and iron gave rise to long Co nanowires and Co-Fe dumbbells and contributed to the definition and the improvement of the experimental conditions for the seeded growth of Co and Fe on the solid substrates

A utilização de Células-tronco e técnicas da Engenharia Tecidual representa um grande avanço tecnológico e beneficiará muitos pacientes com suas conquistas. A descoberta de germes dentários como uma fonte confiável de células-tronco possibilitou diversas pesquisas nesta área. Duailibi et al. (2011) sugeriram uma nova classificação de desenvolvimento dentário baseada pela quantidade de material biológico coletado indicando a necessidade de métodos de diagnóstico por imagem para esta nova classificação. Na literatura diversos trabalhos indicam métodos de classificação dentária e métodos para estimar a idade fisiológica de indivíduos. O presente estudo tem o objetivo de adaptar alguns destes métodos para estimar o estágio de desenvolvimento proposto por Duailibi et al. (2011) consequentemente indicando a quantidade de células-tronco esperadas nas amostras. Para tanto, submeteu-se uma coleção de 67 dentes previamente classificados por Duailibi et al. (2011) à técnica rpcl e à tcfc para a obtenção de imagens e a aplicação de técnicas de estimativas por proporções lineares e volumétricas. Os resultados por análises lineares indicaram valores de R2 para o método de proporção de comprimento CDCP de 0,14050; CCCP de 0,65369; CCCR de 0,5408; CDCR de 0,54074; o método de proporção de área APAD de 0,23925; e método de proporção de volume VPVD de 0,08553, com valor de p menor ou igual à 0,05. Concluindo este estudo indica-se o método de rpcl utilizando a análise do comprimento entre coroa e polpa como o mais indicado para estimar o estágio de desenvolvimento. / The usage of human dental stem cells and tissue engineering technics represents a huge tecnological development and it may benefits many patients in a promissing future. The discovery of suitable source of human dental stem cells were made using tooth buds. Duailibi et al. 2011 indicated a new tooth classification on a stem cell harvesting based research, sugesting new methods for diagnosis these stages. Several method were developed for dental age assesement. The presente study aims to evaluate some of these dental age technics and make adaptations for estimating Duailibi et al. 2011 tooth stages. A 67 tooth sample previoulsy classificated by Duailbi et al. 2011 were submited through periapical parallel long cone X-rays and CBCT analysis. Age estimation ratio methods were applied by measuring tooth/root lenth, crown/root lenth, tooth/pulp lenth, crown/pulp lenth, tooth/poulp área and tooth/pulp volume. Results indicated by linear regression analisys a R2 value of tooth/pulp lenth 0,14050; crown/pulp lenth 0,65369; crown/root lenth 0,5408; tooth/root lenth 0,54074; pulp/tooth volume 0,23925; e tooth/pulp volume de 0,08553, with p value of 0,005. In conclusion , the best method for estimating Duailibi et al. 2011 tooth classification techinic is made by using periapical long cone X-rays using crown/pulp lenth ratio.

A utilização de Células-tronco e técnicas da Engenharia Tecidual representa um grande avanço tecnológico e beneficiará muitos pacientes com suas conquistas. A descoberta de germes dentários como uma fonte confiável de células-tronco possibilitou diversas pesquisas nesta área. Duailibi et al. (2011) sugeriram uma nova classificação de desenvolvimento dentário baseada pela quantidade de material biológico coletado indicando a necessidade de métodos de diagnóstico por imagem para esta nova classificação. Na literatura diversos trabalhos indicam métodos de classificação dentária e métodos para estimar a idade fisiológica de indivíduos. O presente estudo tem o objetivo de adaptar alguns destes métodos para estimar o estágio de desenvolvimento proposto por Duailibi et al. (2011) consequentemente indicando a quantidade de células-tronco esperadas nas amostras. Para tanto, submeteu-se uma coleção de 67 dentes previamente classificados por Duailibi et al. (2011) à técnica rpcl e à tcfc para a obtenção de imagens e a aplicação de técnicas de estimativas por proporções lineares e volumétricas. Os resultados por análises lineares indicaram valores de R2 para o método de proporção de comprimento CDCP de 0,14050; CCCP de 0,65369; CCCR de 0,5408; CDCR de 0,54074; o método de proporção de área APAD de 0,23925; e método de proporção de volume VPVD de 0,08553, com valor de p menor ou igual à 0,05. Concluindo este estudo indica-se o método de rpcl utilizando a análise do comprimento entre coroa e polpa como o mais indicado para estimar o estágio de desenvolvimento. / The usage of human dental stem cells and tissue engineering technics represents a huge tecnological development and it may benefits many patients in a promissing future. The discovery of suitable source of human dental stem cells were made using tooth buds. Duailibi et al. 2011 indicated a new tooth classification on a stem cell harvesting based research, sugesting new methods for diagnosis these stages. Several method were developed for dental age assesement. The presente study aims to evaluate some of these dental age technics and make adaptations for estimating Duailibi et al. 2011 tooth stages. A 67 tooth sample previoulsy classificated by Duailbi et al. 2011 were submited through periapical parallel long cone X-rays and CBCT analysis. Age estimation ratio methods were applied by measuring tooth/root lenth, crown/root lenth, tooth/pulp lenth, crown/pulp lenth, tooth/poulp área and tooth/pulp volume. Results indicated by linear regression analisys a R2 value of tooth/pulp lenth 0,14050; crown/pulp lenth 0,65369; crown/root lenth 0,5408; tooth/root lenth 0,54074; pulp/tooth volume 0,23925; e tooth/pulp volume de 0,08553, with p value of 0,005. In conclusion , the best method for estimating Duailibi et al. 2011 tooth classification techinic is made by using periapical long cone X-rays using crown/pulp lenth ratio.

La motivation de cette thèse est la production innovante de germes ultra-minces de silicium cristallin. L’utilisation de tels germes dans un procédé de fabrication de cellules solaires permettrait une réduction importante de la consommation de silicium, qui compte déjà pour 60% du coût de production des panneaux solaires de première génération. Dans le cadre de cette thèse, une méthode pionnière de détachement de germes minces a été mise en oeuvre. Dans cette méthode, une contrainte induite mécaniquement est guidée par des défauts étendus induits par l’implantation d’hydrogène. Par cette méthode, le détachement de germes minces d’environ 710nm d’épaisseurs a été obtenu. Le but est ensuite d’utiliser ces germes pour faire croitre du silicium cristallin avec des épaisseurs variables à souhait, soit une technique kerf-free : sans pertes. Cette étude présente ainsi les étapes menant à la mise en oeuvre de ce procédé : en premier lieu, un état de l’art des méthodes de détachement de films ultra-minces existants est réalisé. Celui-ci nous a ainsi guidés vers l’implantation d’hydrogène en tant que méthode viable du guidage de la fracture. Par la suite, différents tentatives de détachement de germes ultra-minces ont été réalisés puis caractérisés, notamment par MEB, MET, AFM et DRX. Dans de bonnes conditions de collage et de croissance de défauts, le détachement de germes ultra-minces de silicium cristallin a été réalisé. Par la suite, la croissance et la cristallisation de couches de silicium amorphe a été réalisée sur les germes détachés. Pour finir, certaines couches détachées ont été utilisées pour la production de cellules solaires prototypes. / The goal of this thesis is to find an innovative way to produce ultra-thin crystalline silicon seeds. The use of such seeds in a solar cell production process could lead to a significant reduction of the silicon consumption, which cost alone is worth 60% of the total cost of a first generation solar panel. Within the context of this PhD thesis, a pioneer seed exfoliation method was implemented. This method use the defects induced by hydrogen implantation to guide a stress-induced spalling process. This method has allowed the exfoliation of 710nm-thick crystalline silicon seeds. These seeds will then be used for the growth of crystalline silicon layers of any desired thickness, hence a totally kerf-free method. This thesis work presents the steps leading to the implementation of this process: firstly, the state of the art of ultra-thin films exfoliation methods is reviewed, which guided us towards the use of hydrogen implantation as a crack guide. Then, different ultra-thin seeds exfoliation processes were tried and characterized, specifically by SEM, TEM, AFM and XRD. In the right conditions of bonding and defects growth, ultra-thin silicon seeds were successfully exfoliated. The growth and crystallization of amorphous silicon layers on these seeds were then studied. Finally, several exfoliated layers were used for the production of prototype solar cells.