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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Reparo meniscal em crianças e adolescentes : uma revisão sistemática de resultados

Ferrari, Márcio Balbinotti January 2018 (has links)
OBJETIVO: Realizar uma revisão sistemática da literatura existente, a fim de analisar os resultados após o reparo meniscal na população pediátrica. MÉTODOS: Uma revisão sistemática foi realizada de acordo com as diretrizes PRISMA usando os Bancos de Dados de Análise Sistemática Cochrane, Registro Central Cochrane de ensaios controlados, MEDLINE Ovid e MEDLINE PubMed. Os critérios de inclusão foram os seguintes: estudos que relatam os resultados do reparo meniscal em pacientes com 18 anos ou menos, com um seguimento médio mínimo de 12 meses, idiomas português, espanhol ou inglês e estudos humanos incluindo 10 ou mais pacientes. RESULTADOS: Nossa pesquisa identificou 2534 títulos individuais. Após a aplicação dos critérios de inclusão e exclusão, foram incluídos oito estudos, avaliando 287 pacientes com lesões meniscais reparadas. Sete estudos foram classificados como nível de evidência IV e um nível III. O escore médio MINORS foi de 8,6 ± 1,4. O reparo meniscal incluiu todas as zonas meniscais e padrões de lesões. A lesão do ligamento cruzado anterior foi a lesão associada mais comum. As técnicas “inside-out” e “all-inside” foram predominantemente relatadas. A maioria dos pacientes relatou resultados bons a excelentes e teve sinais clínicos de cicatrização meniscal; as meniscectomias após reparação meniscal foram realizadas em apenas 44 casos. CONCLUSÃO: Lesões meniscais em pediatria não são incomuns. O reparo desta lesão foi associado com resultados bons a excelentes na maioria dos pacientes, independentemente do padrão de lesão, zona ou técnica. As complicações relatadas foram mínimas, no entanto, são necessários estudos de maior qualidade para confirmar os achados desta revisão sistemática. NÍVEL DE EVIDÊNCIA: Nivel IV, revisão sistemática de estudos nível III e nível IV. / PURPOSE: To perform a systematic review of existing literature in order to analyze outcomes after meniscal repair in the pediatric population. METHODS: A systematic review was performed according to PRISMA guidelines using the Cochrane Database of Systematic Review, Cochrane Central Register of Controlled Trials, MEDLINE Ovid, and MEDLINE PubMed databases. Inclusion criteria were as follows: studies reporting the outcomes of meniscal repair in patients 18 years old or younger, with a minimum mean follow-up of 12 months, Portuguese, Spanish or English languages, and human studies including 10 or more patients. RESULTS: Our search identified 2534 individual titles. After application of the inclusion and exclusion criteria, 8 studies were included, evaluating 287 patients with repaired meniscal tears. Seven studies were classified as level of evidence IV and one level III. The mean MINORS score was 8.6 ± 1.4. Meniscal repair included all meniscal zones and tear patterns. Anterior cruciate ligament tear was the most common associated injury. The all-inside and inside-out techniques were predominantly reported. The majority of the patients reported good to excellent outcomes and had clinical signals of meniscal healing; meniscectomies following meniscal repair were performed in just 44 cases. CONCLUSION: Meniscal tears in pediatrics are not uncommon. Repairs of this injury were associated with good to excellent outcomes in most patients, regardless of the injury pattern, zone or technique. Reported complications were minimal, however, higher quality studies are needed to confirm the findings of this systematic review. LEVEL OF EVIDENCE: Level IV, systematic review of Level III and Level IV studies.
52

Reparo meniscal em crianças e adolescentes : uma revisão sistemática de resultados

Ferrari, Márcio Balbinotti January 2018 (has links)
OBJETIVO: Realizar uma revisão sistemática da literatura existente, a fim de analisar os resultados após o reparo meniscal na população pediátrica. MÉTODOS: Uma revisão sistemática foi realizada de acordo com as diretrizes PRISMA usando os Bancos de Dados de Análise Sistemática Cochrane, Registro Central Cochrane de ensaios controlados, MEDLINE Ovid e MEDLINE PubMed. Os critérios de inclusão foram os seguintes: estudos que relatam os resultados do reparo meniscal em pacientes com 18 anos ou menos, com um seguimento médio mínimo de 12 meses, idiomas português, espanhol ou inglês e estudos humanos incluindo 10 ou mais pacientes. RESULTADOS: Nossa pesquisa identificou 2534 títulos individuais. Após a aplicação dos critérios de inclusão e exclusão, foram incluídos oito estudos, avaliando 287 pacientes com lesões meniscais reparadas. Sete estudos foram classificados como nível de evidência IV e um nível III. O escore médio MINORS foi de 8,6 ± 1,4. O reparo meniscal incluiu todas as zonas meniscais e padrões de lesões. A lesão do ligamento cruzado anterior foi a lesão associada mais comum. As técnicas “inside-out” e “all-inside” foram predominantemente relatadas. A maioria dos pacientes relatou resultados bons a excelentes e teve sinais clínicos de cicatrização meniscal; as meniscectomias após reparação meniscal foram realizadas em apenas 44 casos. CONCLUSÃO: Lesões meniscais em pediatria não são incomuns. O reparo desta lesão foi associado com resultados bons a excelentes na maioria dos pacientes, independentemente do padrão de lesão, zona ou técnica. As complicações relatadas foram mínimas, no entanto, são necessários estudos de maior qualidade para confirmar os achados desta revisão sistemática. NÍVEL DE EVIDÊNCIA: Nivel IV, revisão sistemática de estudos nível III e nível IV. / PURPOSE: To perform a systematic review of existing literature in order to analyze outcomes after meniscal repair in the pediatric population. METHODS: A systematic review was performed according to PRISMA guidelines using the Cochrane Database of Systematic Review, Cochrane Central Register of Controlled Trials, MEDLINE Ovid, and MEDLINE PubMed databases. Inclusion criteria were as follows: studies reporting the outcomes of meniscal repair in patients 18 years old or younger, with a minimum mean follow-up of 12 months, Portuguese, Spanish or English languages, and human studies including 10 or more patients. RESULTS: Our search identified 2534 individual titles. After application of the inclusion and exclusion criteria, 8 studies were included, evaluating 287 patients with repaired meniscal tears. Seven studies were classified as level of evidence IV and one level III. The mean MINORS score was 8.6 ± 1.4. Meniscal repair included all meniscal zones and tear patterns. Anterior cruciate ligament tear was the most common associated injury. The all-inside and inside-out techniques were predominantly reported. The majority of the patients reported good to excellent outcomes and had clinical signals of meniscal healing; meniscectomies following meniscal repair were performed in just 44 cases. CONCLUSION: Meniscal tears in pediatrics are not uncommon. Repairs of this injury were associated with good to excellent outcomes in most patients, regardless of the injury pattern, zone or technique. Reported complications were minimal, however, higher quality studies are needed to confirm the findings of this systematic review. LEVEL OF EVIDENCE: Level IV, systematic review of Level III and Level IV studies.
53

Crescimento de fibrocondrócitos sobre arcabouço de PLDLA/PCL-T para aplicação como prótese de menisco / Fibrochondrocytes ingrowth on PLDLA/PCL-T scaffolds asmeniscus prosthesis

Esposito, Andrea Rodrigues 16 August 2018 (has links)
Orientador: Eliana Aparecida de Rezende Duek / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-16T07:55:59Z (GMT). No. of bitstreams: 1 Esposito_AndreaRodrigues_M.pdf: 4037379 bytes, checksum: 0972d6543df2aa3ece0f74e93c30dfc4 (MD5) Previous issue date: 2010 / Resumo: A engenharia tecidual utilizando células fibrocartilaginosas e arcabouços poliméricos representa uma alternativa para o tratamento de lesões do menisco. Neste estudo, arcabouços de PLDLA/PCL-T (90/10) contendo sacarose (50% m/v) foram obtidos por evaporação de solvente. Fibrocondrócitos provenientes do menisco de coelhos foram isolados e semeados diretamente sobre os arcabouços. Estudos in vitro demonstraram que o arcabouço não apresentou citotoxicidade e permitiu a adesão e o crescimento de fibrocondrócitos, bem como manutenção da síntese de matriz extracelular colágena nos tempos de 7, 14, 21 e 28 dias de cultivo. Os implantes de PLDLA/PCL-T foram realizados no menisco medial do joelho de 20 coelhos, após a meniscectomia total, obtendo-se três tratamentos: arcabouço com pré-cultivo celular por 21 dias, arcabouço sem células e controle. Após 12 e 24 semanas, as análises histológicas dos "neomeniscos" apresentaram a formação de fibrocartilagem nos implantes com os arcabouços. A presença de tecido fibrocartilaginoso maduro com fibras colágenas organizada foi predominantemente observada nos implantes realizados com os arcabouços pré-cultivados em comparação com os implantes sem células após 24 semanas. Este estudo demonstrou que a regeneração de uma importante estrutura fibrocartilaginosa pode ser alcançada utilizando arcabouço polimérico biorreabsorvível e células alógenas dentro dos princípios da engenharia de tecidos / Abstract: Tissue engineering of meniscus using fibrochondrocyte-like cells and bioreabsorbable polymer scaffolds could be an alternative option to treat meniscus injury. In this study PLDLA/PCL-T (90/10) scaffolds containing sucrose (50% m/v) were obtained by casting. Allogeneic meniscal cells were isolated from rabbit meniscus and directly seeded onto the scaffolds. In vitro studies showed that scaffolds did not present cytotoxicity and allowed fibrochondrocytes adhesion and ingrowth, as well as collagen extracellular matrix synthesis at 7, 14, 21 and 28 days of culture. The PLDLA/PCL-T implants were performed in the medial meniscus of 20 rabbit knee after total meniscectomy, obtained three treatments: pre-seeded 21 days scaffold, unseeded scaffold and control. Histology analysis of "neomenisci" sections at 12 and 24 weeks revealed the presence of fibrocartilage in the polymer implants. The presence of mature fibrocartilaginous tissue with organized collagen fibers was predominantly observed in the pre-cultured implants compared to unseeded implants after 24 weeks. This study demonstrates that regeneration of an important fibrocartilaginous structure can be achieved using a bioreabsorbable polymer scaffold and allogeneic cells-based tissue engineering approaches / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica
54

Processamento, caracterização e desempenho in vivo de arcabouço biorreabsorvível de PLDLA-co-TMC / Processing, characterization and in vivo performance of the bioresorbable PLDLA-co-TMC scaffold

Cabrera, Andrea Rodrigues Espósito, 1986- 25 August 2018 (has links)
Orientador: Eliana Aparecida de Rezende Duek / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-25T20:37:05Z (GMT). No. of bitstreams: 1 Cabrera_AndreaRodriguesEsposito_D.pdf: 56970103 bytes, checksum: 0ab20c99ece698f3eb8622ada3260515 (MD5) Previous issue date: 2014 / Resumo: Estruturas tridimensionais têm sido obtidas por diversas técnicas e representam um importante enfoque no desenvolvimento de suportes porosos para a engenharia tecidual. O objetivo deste trabalho foi desenvolver e caracterizar arcabouços tridimensionais porosos de poli(L-co-D,L ácido lático-co-trimetileno carbonato), PLDLA-co-TMC, obtidos pela técnica de deposição de fibras 3D. Arcabouços do terpolímero PLDLA-co-TMC, nas proporções 70:30 e 50:50, foram obtidos e caracterizados por microscopia eletrônica de varredura, cromatografia de permeação em gel, calorimetria exploratória diferencial, análise termogravimétrica, ensaio mecânico de compressão e estudo de degradação in vitro, os quais evidenciaram suas características amorfas, geometria cilíndrica e poros interconectados. O estudo de degradação in vitro, apresentou expressiva perda das propriedades mecânicas compatíveis com queda na massa molar, acompanhada de alterações na morfologia. Avaliou-se a histocompatibilidade da associação de células-tronco mesenquimais provenientes da medula óssea de coelhos e arcabouços de PLDLA-co-TMC (70:30), obtidos pelo método de evaporação de solvente com adição de sacarose (50%), na regeneração do menisco. Nove coelhos Nova Zelândia foram submetidos a meniscectomia medial total, obtendo-se três tratamentos: implante do arcabouço de PLDLA-co-TMC com pré-cultivo celular, implante de arcabouço de PLDLA-co-TMC puro (sem células) e controle negativo (defeito sem implante). Após 24 semanas, os resultados evidenciaram a presença de fibrocartilagem nos animais tratados com arcabouço polimérico. Contudo, a regeneração obtida com arcabouços de PLDLA-co-TMC pré-cultivados com células-tronco mesenquimais apresentou-se semelhante ao tecido fibrocartilaginoso maduro do menisco normal, tanto macroscopicamente quanto histologicamente. Este estudo demonstrou a eficácia do arcabouço de PLDLA-co-TMC (70:30) na regeneração fibrocartilaginosa e o potencial do pré-cultivo de células mesenquimais na engenharia tecidual, sem o uso de fatores de crescimento. Conclui-se que os polímeros biorreabsorvíveis representam uma alternativa promissora para a regeneração tecidual / Abstract: Three-dimensional structures have been obtained by various techniques and are an important focus in the development of porous scaffolds for tissue engineering. The aim of this study was to develop and characterize three-dimensional porous scaffolds of poly (L-co-D, L lactide-co-trimethylene carbonate), PLDLA-co-TMC, obtained by 3D fiber deposition technique. The PLDLA-co-TMC terpolymer scaffolds, 70:30 and 50:50, were obtained and characterized by scanning electron microscopy, gel permeation chromatography, differential scanning calorimetry, thermal gravimetric analysis, compression mechanical testing and study on in-vitro degradation, which exhibited its amorphous characteristics, cylindrical geometry and interconnected pores. The in-vitro degradation study showed significant loss of mechanical properties compatible with a decrease in molar mass, accompanied by changes in morphology. The histocompatibility association of mesenchymal stem cells from rabbits bone marrow, and PLDLA-co-TMC (70:30) scaffolds, obtained by casting with sucrose (50%), was evaluated in the meniscus regeneration, proving the potential of cell culture at in vivo tissue regeneration. Nine New Zealand rabbits underwent total medial meniscectomy, yielding three treatments: implantation of the seeded PLDLA-co-TMC scaffold, implantation of the unseeded PLDLA-co-TMC and negative control (defect without any implant). After 24 weeks, the results revealed the presence of fibrocartilage in the animals treated with polymer. However, the regeneration obtained with the seeded PLDLA-co-TMC scaffolds with mesenchymal stem cells had become intimal to mature fibrocartilaginous tissue of normal meniscus both macroscopically and histologically. This study demonstrated the effectiveness of the PLDLA-co-TMC (70:30) scaffold in meniscus regeneration and the potential of mesenchymal stem cells in tissue engineering, without the use of growth factors. It is concluded that bioresorbable polymers represent a promising alternative for tissue regeneration / Doutorado / Materiais e Processos de Fabricação / Doutora em Engenharia Mecânica
55

Desenvolvimento de menisco de poli(álcool vinílico) (PVA) personalizado com auxílio da prototipagem rápida / Poly (vinyl alcohol) (PVA) meniscus development personalized with the aid of rapid prototyping

Wataya, Celio Hitoshi 20 August 2018 (has links)
Orientadores: Cecilia Amelia de Carvalho Zavaglia, Vanessa Petrilli Bavaresco / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-20T08:05:10Z (GMT). No. of bitstreams: 1 Wataya_CelioHitoshi_D.pdf: 3496514 bytes, checksum: a0aa09bccd8fc730f8ee1b6d7c5f5f37 (MD5) Previous issue date: 2012 / Resumo: O menisco como qualquer outro órgão, possui sua importância no funcionamento total do corpo humano. O tratamento para as lesões do menisco tem sido substituído pelo reparo, entretanto, conforme a gravidade da lesão torna-se inevitável a meniscectomia (cirurgia do menisco). Diante desta situação propôs-se desenvolver uma prótese que substitua o menisco lesionado, que possua suas características dimensionais, bem como suas propriedades mecânicas e tribológicas. A utilização da tecnologia da prototipagem rápida foi fundamental para se alcançar efetivamente o objetivo proposto. O material selecionado para a obtenção dessa prótese foi o poli(álcool vinílico) (PVA), por ser um polímero de baixo custo de produção, fácil obtenção e boas características para ser utilizado como um biomaterial. Os resultados dos ensaios mecânicos confirmaram a eficácia desse material. Valores como módulo de compressão 37,4 MPa (± 1,74), o módulo de fluência a indentação E = 3,6 MPa (±0,6); módulo de tensão e deformação, respectivamente iguais a 'SIGMA' = 3,2 MPa (±0,3) e ? = 148,4% (±39), evidenciam a possibilidade de utilização do PVA também como substituto do menisco humano. Outros ensaios também foram realizados como: ensaio in vitro e in vivo, tribológico e a Calorimetria Diferencial de Varredura (DSC), com resultados favoráveis a esse fim. Para a obtenção do menisco de PVA nas dimensões do menisco do paciente utilizou-se a tecnologia da prototipagem rápida (PR), primeiro para se obter o molde do menisco e depois então, o menisco por envasamento da solução de PVA no molde. Dois detalhes foram fundamentais para se chegar ao produto final, o primeiro foi o tratamento computacional dado à imagem de tomografia do joelho utilizando-se de programas livres como Invesalius e Rhinoceros e o segundo foi o uso do reticulante físico, o reagente orgânico dimetilsulfóxido (DMSO) / Abstract: The meniscus like any other organ, has its importance in the total functioning of the human body. The treatment for meniscal injuries has been replaced by the repair, however, according to the severity of the injury becomes inevitable meniscectomy (meniscus surgery). In this situation it was proposed to develop a prosthesis to replace the injured meniscus, which have their dimensional characteristics as well as their mechanical and tribological properties. The use of rapid prototyping technology was essential to effectively achieve the proposed objective. The material selected for obtaining a prosthesis is poly (vinyl alcohol) (PVA), being a polymer of low production cost, and easy to obtain good characteristics for use as a biomaterial. The results of mechanical tests have confirmed the effectiveness of this material. Values like compression module 37.4 MPa (± 1.74), the modulus of creep indentation E = 3,6 MPa (± 0.6), tensile modulus and strain, respectively equal to ' SIGMA' = 3.2 MPa (± 0.3) and ? = 148.4% (± 39) show the possibility of use of PVA as well as replacement of the meniscus human. Other tests were also conducted as in vitro and in vivo tribological and Differential Scanning Calorimetry (DSC), with results favorable to that end. To obtain the meniscus of PVA in the dimensions of the meniscus of the patient if the technology used rapid prototyping (RP), first to obtain the mold of the meniscus after then, the meniscus by filling the PVA solution in the mold. Two things were essential to reach the final product, the first treatment was given to computer tomography imaging of the knee using free programs like Rhinoceros and InVesalius and the second was the use of physical crosslinking, the organic reagent dimethyl sulfoxide (DMSO) / Doutorado / Materiais e Processos de Fabricação / Doutor em Engenharia Mecânica
56

Caractérisation multi-échelle des ménisques du genou : effet de l'arthrose

Levillain, Aurélie 04 October 2016 (has links)
L’arthrose du genou est une maladie rhumatismale dégénérative touchant tous les tissus de l’articulation. Elle est classée parmi les dix affections les plus invalidantes dans le monde et l’absence de traitement curatif efficace en fait un véritable problème de santé publique. Dans le cas d’arthrose post-traumatique, les lésions méniscales sont fréquentes et entravent leurs fonctions de répartition des efforts, d’absorption des chocs et de stabilité. Les objectifs de ce travail de thèse sont (1) d’analyser les changements de propriétés mécaniques des ménisques à un stade précoce de développement de l’arthrose et de les corréler avec les modifications morphologiques, biochimiques et microstructurales, et (2) d’évaluer l’effet d’une thérapie de viscosupplémentation commerciale. Le modèle d’arthrose post-traumatique choisi dans cette étude est la rupture du ligament croisé antérieur chez le lapin. Les ménisques de lapins sains, arthrosiques non traités et arthrosiques traités ont été caractérisés six semaines après l’opération par un score macroscopique, puis par indentation – relaxation grâce au développement d’une méthode de test adaptée, ainsi que par microspectroscopie Raman, microscopie confocale biphotonique et histologie. Cette étude a révélé la formation de lésions à la surface des ménisques arthrosiques et une diminution de leurs propriétés viscoélastiques, s’expliquant par une désorganisation de leurs fibres de collagène et une diminution de leur quantité de glycosaminoglycanes. Bien que le traitement améliore significativement l’état de surface des ménisques et joue un rôle dans la régulation des glycosaminoglycanes, il a peu d’effet sur l’organisation des fibres de collagène et sur les propriétés viscoélastiques. Ce travail de thèse apporte une meilleure compréhension des modifications affectant le ménisque, dans l’optique de développer de nouveaux traitements. / Knee osteoarthritis (OA) is a rheumatic degenerative disease affecting all tissues of the joint. It is classified among the ten most disabling affections in the world and the lack of efficient curative treatment makes it a real public health issue. In case of post-traumatic OA, meniscal tears are frequent and interfere with their functions of load distribution, shock absorption and stability. The aims of this work are (1) to analyze the changes of mechanical properties of the menisci at an early stage of OA development and to correlate them with morphological, biochemical and microstructural modifications, and (2) to assess the effect of a commercial viscosupplementation therapy. For this study, an anterior cruciate ligament transection model of post-traumatic OA was used in rabbits. Menisci from healthy, non-treated OA and treated OA rabbits were characterized six weeks after surgery through macroscopic grading, indentation-relaxation with the development of an adapted test method, Raman microspectroscopy, biphotonic confocal microscopy and histology. This study revealed the formation of tears at the surface of OA menisci and a decrease in their viscoelastic properties, which was explained by a disorganization of their collagen fibers and a decrease in their glycosaminoglycan content. Although the treatment significantly improves the surface integrity of the menisci and plays a role in the glycosaminoglycan regulation, it has little effect on the organization of their collagen fibers and on their viscoelastic properties. This work brings a better understanding of the disease processes affecting the meniscus, for the purposes of developing new treatments.
57

Etude de nanoménisques par AFM et MEB : hydrodynamique de la couche visqueuse, élasticité de l'interface et dynamique de la ligne de contact / Nanomeniscus studies by AFM and SEM : hydrodynamics of the viscous layer, elasticity of the interface and dynamics of the contact line

Dupre de baubigny, Julien 11 December 2014 (has links)
Le développement récent de la nanofluidique pose de nombreuses questions concernant les lois et longueurs caractéristiques qui régissent l’hydrodynamique et le mouillage à l’échelle du nanomètre. Pour aborder ce sujet, nous avons utilisé des techniques de microscopies avancées en sondant l’interface liquide/air à l’aide de pointes non conventionnelles. L’AFM utilisé dans le mode oscillant modulation de fréquence (FM-AFM) donne accès, de manière indépendante, à la force exercée par le liquide pendant une approche-retrait, et aux composantes conservatives et dissipatives de l’interaction pointe-ménisque. Des expériences complémentaires menées en microscopie électronique (MEB) permettent de visualiser le nanoménisque créé et de mesurer la force capillaire résultante. La couche visqueuse entraînée par l’oscillation de la pointe est d’abord étudiée. Le coefficient de friction et la masse ajoutée sont mesurés par FM-AFM en fonction de la viscosité des liquides et de la fréquence d’excitation. Un modèle basé sur une description classique rend compte quantitativement de l’ensemble des résultats expérimentaux permettant ainsi une évaluation du champ de vitesse entraîné par la nanosonde.Les méthodes développées ont permis d’étudier les caractéristiques de l’interface liquide. Le profil du nanoménisque est modélisé et validé grâce aux observations MEB. La raideur du ménisque mesurée expérimentalement par FM-AFM et décrite théoriquement démontre une dépendance logarithmique avec l’extension latérale du ménisque.Des résultats préliminaires sont également obtenus avec des pointes de carbone sur lesquelles glisse la ligne de contact, donnant accès à la dissipation dans le nanoménisque et à la ligne de contact, ainsi qu’à l’ancrage sur des défauts uniques, un des problèmes ouverts de la physique du mouillage.Cette étude démontre que le FM-AFM et le MEB sont des outils pertinents pour sonder quantitativement les propriétés des liquides à l’échelle nanométrique, ouvrant la voie à des études systématiques sur le mouillage à l’échelle nanométrique / The recent development of nanofluidic raises many issues about laws and characteristic lengths governing hydrodynamics and wetting at the nanometer scale. To address this issue, we used advanced microscopy techniques to probe the liquid/air interface with unconventional tips. The oscillating frequency modulation mode (FM-AFM) of the Atomic Force Microscope (AFM) gives independent access to the force applied by the liquid during an approach-withdrawal ramp, and to the conservative and dissipative components of the tip-meniscus interaction. Additional experiments conducted by electron microscopy (SEM) helped visualizing the shape of nanomeniscus to measure the resulting capillary force.The viscous layer set in motion by the oscillation of the tip is studied first. The friction coefficient and the added mass are measured by AFM-FM as a function of the viscosity of the liquid and of the excitation frequency. A model based on a classical description reflects quantitatively all experimental results enabling an evaluation of the velocity field caused by the nanoprobe.The developed methods also served to study the properties of the liquid interface. Nanomeniscus profile is modeled and validated through SEM observations. The stiffness measured experimentally by FM-AFM and described theoretically shows a logarithmic dependence with the lateral extension of the meniscus.Preliminary results are also obtained with carbon tips on which the contact line slides, giving access to the energy dissipation in the nanomeniscus and at the contact line, as well as to the anchoring of single defaults, an open issue of wetting physics.This study demonstrates that FM-AFM and SEM are relevant tools to probe quantitatively the properties of liquids at the nanoscale, opening the way for systematic studies on wetting at the nanoscale
58

Návrh kinematiky a řezné geometrie funkční části artroskopických kleští / On the cutting geometry and kinematics of the arthroscopic forceps part

Pospíchal, Oldřich January 2014 (has links)
This Thesis presents a design innovation in arthroscopic forceps. Based on surveying the subject-matter literature on arthroscopic surgery of the knee, design changes are proposed to alter the cutting geometry of the functional end of the instrument to improve its utility. The proposed changes are imple-mented in a prototype, which is then compared with the current design. The comparison is made by testing the functioning of the instrument and the force required to shear the test material.
59

Compound meniscus implant prototypes : Bench test performance of knitted casing to contain, fixate and mechanically stabilize cell seeded gels

Ydrefors, Maria January 2021 (has links)
Meniscal tears are the most common intra-articular injury of the knee joint. Due to the avascular zone with limited blood supply, treatment of the injury is a complex process. Today, research on the development of efficient treatments and meniscal replacements is of increasing interest. However, there are few alternatives of meniscal replacements available on the market and research has shown uncertain results in their ability to restore the natural biomechanics of the knee joint or prevent development of osteoarthritis. Furthermore there is no comparable method to evaluate tensile stresses caused by axial compressional load on a whole meniscus replacement. Therefore the possibility of knitted casing to contain, fixate and mechanically stabilize a cell seeded bioprinted gel and develop a methodology to characterize its compressional behaviour was analysed. By interlock knitting with segments of partial knit a 3D crescent-shaped biodegradable casing was produced mimicking the dimension of the medial meniscus. In the casing design, an Artelon® Flexband™ was incorporated functioning both as reinforcement at the peripheral rim and as fixation method. Moreover radial threads were added to the casing design by inclusion of weft inlays in the knitting pattern. In the non-destructive characterization of the compressional behaviour of the prototype, axial compressional forces of 10.82 N and 29.77 N were achieved. However the forces achieved were significantly lower if compared to the high force that is applied to the menisci in the knee joint. Furthermore a high influence of the coefficient of friction of the casing in the axial compressional force was concluded. Nevertheless refinements of the methodology are required to perform evaluation with comparable and reliable results.
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Improvement of Photovoltaic Properties of Solar Cells with Organic and Inorganic Films Prepared by Meniscuc Coating Technique / メニスカス塗布技術で作製した有機及び無機フィルムを用いた太陽電池光電変換特性の改良

ANUSIT, KAEWPRAJAK 25 March 2019 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(エネルギー科学) / 甲第21884号 / エネ博第385号 / 新制||エネ||75(附属図書館) / 京都大学大学院エネルギー科学研究科エネルギー基礎科学専攻 / (主査)教授 佐川 尚, 教授 萩原 理加, 教授 野平 俊之 / 学位規則第4条第1項該当 / Doctor of Energy Science / Kyoto University / DGAM

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