Tesis sobre el tema "Artificial implants"
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1
Swamy, Amit. "Development of laboratory spine with artificial muscles". Thesis, University of Hull, 2007. http://hydra.hull.ac.uk/resources/hull:780.
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There is an increasing demand for spinal surgery and a growing number of new spinal implants and surgical procedures being offered by orthopaedic companies. However, the testing of spinal implants and spinal instrumentation is problematic, with testing in cadavers and animals becoming increasingly difficult and both having significant limitations. Thus the aim of this research is to develop an artificial laboratory spine that will have the same physical and biomechanical properties as the human spine. Validation of computer model is difficult hence an active artificial laboratory spine is being developed. A number of spinal elements have been produced and are being investigated, including an artificial intervertebral disc with different material properties to allow it to simulate different clinical conditions. The study is the first of its kind with the characteristics of the disc material that have been assessed in the laboratory, artificial muscles and spring elements and with normal physiological movements compared and validated from the reported literature. The model was used to investigate the potential of Shape Memory Alloy wires to act as artificial muscles and to control the movement of the spine. It is anticipated that the laboratory spine will have a number of other applications, in particular in the assessment of spinal instrumentation and testing. An actual geometry laboratory spine is also generated with suitable manufacturing technique for intervertebral disc, which has an accurate surface profile to fit between the two vertebral bodies above and below it, is discussed in this thesis.
2
Zeng, Shengyue. "Bonnet polishing of cobalt chrome alloys for artificial implants". Thesis, University of Huddersfield, 2014. http://eprints.hud.ac.uk/id/eprint/19751/.
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Cobalt chrome (CoCr) alloys are the most extensively used biomaterials for manufacturing artificial implants which need nanometre scale surface finish and micrometre scale form tolerance to allow long term survival in vivo. Traditional finishing of these devices is usually carried out by manual or simple robot polishing which are time-consuming and labour-intensive. The aim of this thesis is to investigate and develop a deterministic polishing process for improving the surface finish and form tolerance of the bearing surfaces of artificial implants. In order to improve the surface finish for CoCr alloys, a Taguchi method with the consideration of interaction effects was applied to optimise the process parameters. By using the optimised process parameters, the surface roughness of workpieces can be improved up to 8nm Sa, which is far better than 50nm Ra, the recommended value of ISO 7206-2:2011 for metallic bearing surface of artificial implants. The evolution of all 15 parameters of surface topography during polishing process has been investigated. In addition, the effects of the combination of polishing cloths/pads and abrasives on surface topography have been investigated as well, indicating that both polishing cloths/pads and abrasives can affect the improvement of surface topography. A deterministic polishing process is dependent on the material removal which is controlled by process parameters. The way of which material removal and polishing forces were affected by the process parameters has been investigated. Based on the experimental data, a modified Preston equation model was created to predict the material removal rate for bonnet polishing of CoCr alloys. Form tolerance plays a very significant role in the bearing surfaces of artificial implants. By using the method of form correction, a new design of multi-radius femoral head which is unable to be fabricated by traditional polishing process was successfully manufactured. In addition, form correction was also applied to a roughly ground freeform knee femoral component. The success of the form correction experiments indicated that bonnet polishing is a robust technology when applied to the surfaces of artificial implants.
3
Santos, Alex Eugênio dos [UNESP]. "Desenvolvimento de parafuso de interferência bioabsorvível para cirurgia de joelho em PLDL (poli ácido lático) e compósito PLDL + βTCP (beta trifosfato de cálcio)". Universidade Estadual Paulista (UNESP), 2015. http://hdl.handle.net/11449/124038.
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000825246.pdf: 3464292 bytes, checksum: 907652ea25dcfa1a9a30ba9ee22fa099 (MD5)O parafuso de interferência é o dispositivo de fixação mais usados em cirurgias de reconstrução ligamentar de joelho. O uso dos polímeros bioabsorvíveis está sendo cada vez mais utilizados nesta aplicação, devido suas vantagens relacionadas à excelente biocompatibilidade, bioabsorção, integração do enxerto/osso e também facilidade na revisão cirúrgica. O presente estudo tem por objetivo tem por objetivo o desenvolvimento de um parafuso de interferência bioabsorvível fabricado através do processo de injeção em dois polímeros bioabsorvíveis: PLDL (Poli L-D-ácido lático) e um compósito de PLDL+30% TCP (β Trifosfato de Cálcio). Para o desenvolvimento do projeto do produto foi usado um programa de análise estrutural por elementos finitos, de forma a obter a melhor geometria do encaixe de ferramenta. Através dos estudos de simulação por elementos finitos foi possível selecionar a geometria com maior resistência mecânica levando em conta o esforço de torção e além disso foi possível analisar a influência de furos transversais nas tensões mecânicas geradas pelos esforços de torção. Após a definição da melhor geometria, foram fabricadas amostras dos parafusos com os dois polímeros selecionados, os quais foram esterilizados por ETO (Óxido de etileno). Foram realizados testes mecânicos de torque inserção e torque de ruptura. A resistência mecânica do parafuso foi avaliada através da comparação entre os valores do torque de inserção comparando-se com o torque máximo de ruptura. Para contribuir o estudo foi executado teste de degradação in vitro, durante um período de 180 dias, onde foi avaliada a perda de massa dos implantes, resistência mecânica e queda do peso molecular dos implantes. Logo foi possível avaliar o compartamento mecânico dos implantes em degradação comparando-os com os requerimentos da aplicação. Pode-se observar que a degradação molecular do implante ao longo dos...
The interference screw is the fixation device most selected for Knee ligament reconstruction surgeries. The use of Bioabsorbable polymers in interference screws for this application is increasing due it has advantages like excellent biocompatibility, bioabsorption, good integration between graft / bone and also facility in the surgical revision. The aims of the present study were to develop a bioabsorbable interference screw manufactured by the injection moulding process with two distinct polymeric materials: PLDL, Poly(L,DL-Latic acid) and a composite PLDL + 30% TCP (β Tricalcium phosphate). A program for structural analysis by finite elements was used in the development of the screw design, in the intend to make the best geometry fit for the tool. Trough the study by finite elements simulation it was possible to chose the geometry with higher mechanical resistance taking in the account the torsion effort and analyse the influence of transversals holes in the mechanical tensions made by the torque efforts. After the definition of the best geometry, samples of the screw were manufactured with the two selected polymers, sterilized with ETO (ethylene oxide). Were performed mechanical tests, insertion test and torque to break. The mechanical strenght of the screw was evaluated through the comparison between the values of insertion torque and maximum rupture. In addition, a in vitro, degradation test was performed over a period of 180 year days. It was observed, the weight loss, mechanical strength of the implants was evaluated, and molecular weight drops of the implants. Therefore it was possible to evaluate the mechanical behavior in degradation and compare with the application requirements. It can be observed that the raise of the molecular degradation of the implant along the months had as result a loss of the mechanical resistance of the screw, ina slowly and gradual way for the PLDL material, yet the composite material (PLDL+TCP)...
4
Soranz, Filho João Edward [UNESP]. "O uso de implantes orbitários no reparo de cavidades anoftálmicas". Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/86305.
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soranzfilho_je_me_botfm.pdf: 1652118 bytes, checksum: 7a01edbccd06925523118f49c1d42b63 (MD5)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Universidade Estadual Paulista (UNESP)
Alterações oculares, em especial a perda de volume nas cavidades evisceradas, promovem uma série de modificações ao paciente tanto funcional do órgão quanto psicológica e estética. Uma grande preocupação ao longo do tempo é a procura de um material que possa preencher o volume perdido de forma a dar um maior conforto no ponto de visto psicológico e estético ao paciente. Para contribuir nessa direção, esse trabalho teve como objetivo testar experimentalmente prótese de polietileno granulado de ultra-alto peso molecular, material de baixo custo, em órbitas de coelhos submetidos à evisceração cirúrgica em vários tempos experimentais, onde foram avaliados aspectos macroscópicos e microscópicos e de toxicidade sistêmica do material. Os resultados desse trabalho mostram que o material utilizado no implante de cavidade não apresenta alteração significativa nos parâmetros analisados quando comparados ao grupo controle. Sendo resultados bastante promissores indicando que o implante de polietileno poroso desenvolvido por uma indústria nacional tem alto potencial para se realizar testes em humanos
Ocular changes especially the loss of volume in eviscerated cavities promotes several modifications to patients – organ functioning and psychological and esthetical changes. A material that could replace the lost volume in order to guarantee to patients more psychological and esthetical comfort has long been worryingly searched. Contributing in this direction this work aimed at testing experimentally a prosthesis polyethylene granulate of ultra-high molecular weight made of a low cost material to be implanted in orbit of rabbits through surgical evisceration during several experimental times to assess macroscopic and microscopic aspects of systemic toxicity of the respective material. The results show that the material used for the implant of the prosthesis in the cavity does not present significant alteration in the analysed parameters when compared to the control group. Thus, we point with this study promising results indicating that the porous polyethylene implant developed by a national enterprise presents high potential to be tested in humans
5
Estambasse, Eduardo Costa [UNESP]. "Análise de materiais para sistemas de fechamento ósseo através da caracterização superficial e comportamento mecânico". Universidade Estadual Paulista (UNESP), 2015. http://hdl.handle.net/11449/132584.
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000846960.pdf: 3346900 bytes, checksum: 6c18e59b1faa366606936b934172298a (MD5)Neste trabalho busca-se observar um estudo de caracterização mecânica em materiais destinados a implantes, a caracterização superficial dos corpos de provas usinados dos três tipos de materiais utilizados nos implantes para fechamento ósseo titânio grau cinco, titânio grau quatro e aço inox 316 L, estes três tipos de materiais são considerados como biomateriais pois possuem todas as propriedades necessárias para reconstrução óssea, e tem provado ser eficiente para implantes. Este estudo se dará através da aplicação detalhada de ensaios de caracterização superficial e propriedades mecânicas. Um estudo da rugosidade dos materiais antes do implante e a determinação do módulo de cisalhamento e elasticidade utilizando um método não destrutivo foram utilizados. Será apresentado uma síntese dos diferentes tipos de fixação e comparados aos resultados dos ensaios nos materiais. Nos materiais usinados em formatos de discos, foram coletadas imagens num mmicroscópio confocal, e foi realizada análise da superfície com a finalidade de obtenção da rugosidade média quadrática de cada material a fim de identificar a melhor condição de superfície. Uma revisão de literatura fundamentará o estudo proposto
In this work the aim is to observe a mechanical characterization study materials for implants, the surface characteristics of the machined test samples of three types of materials used in bone implants for closing five grade titanium, and titanium grade for stainless steel 316 L, there three types of materials are considered as biomaterials because they posses the necessary properties for bone reconstruction, and has proven to be efficient for implants. This study will be through the detailed application of surface characterization and mechanical properties testing. A study of the roughness of the material before implantation and determining the shear modulus and elasticity using a non-destructive method were used. A summary of different types of fasteners and compared to the test results on the materials will be presented. In machined materials dise formats, images were collected on a confocal microscope, and surface analysis was performed for the purpose of obtaining the mean roughness and mean square surface roughness in order to identify the best surface condition. A literature review reasons or the proposed study
6
Santos, Alex Eugênio dos. "Desenvolvimento de parafuso de interferência bioabsorvível para cirurgia de joelho em PLDL (poli ácido lático) e compósito PLDL + βTCP (beta trifosfato de cálcio) /". Bauru, 2015. http://hdl.handle.net/11449/124038.
Texto completoResumen
Orientador: Luiz Eduardo de Ângelo SanchezBanca: Bento Rodrigues de Pontes Junior
Banca: Arthur Alves Fiocchi
Resumo: O parafuso de interferência é o dispositivo de fixação mais usados em cirurgias de reconstrução ligamentar de joelho. O uso dos polímeros bioabsorvíveis está sendo cada vez mais utilizados nesta aplicação, devido suas vantagens relacionadas à excelente biocompatibilidade, bioabsorção, integração do enxerto/osso e também facilidade na revisão cirúrgica. O presente estudo tem por objetivo tem por objetivo o desenvolvimento de um parafuso de interferência bioabsorvível fabricado através do processo de injeção em dois polímeros bioabsorvíveis: PLDL (Poli L-D-ácido lático) e um compósito de PLDL+30% TCP (β Trifosfato de Cálcio). Para o desenvolvimento do projeto do produto foi usado um programa de análise estrutural por elementos finitos, de forma a obter a melhor geometria do encaixe de ferramenta. Através dos estudos de simulação por elementos finitos foi possível selecionar a geometria com maior resistência mecânica levando em conta o esforço de torção e além disso foi possível analisar a influência de furos transversais nas tensões mecânicas geradas pelos esforços de torção. Após a definição da melhor geometria, foram fabricadas amostras dos parafusos com os dois polímeros selecionados, os quais foram esterilizados por ETO (Óxido de etileno). Foram realizados testes mecânicos de torque inserção e torque de ruptura. A resistência mecânica do parafuso foi avaliada através da comparação entre os valores do torque de inserção comparando-se com o torque máximo de ruptura. Para contribuir o estudo foi executado teste de degradação in vitro, durante um período de 180 dias, onde foi avaliada a perda de massa dos implantes, resistência mecânica e queda do peso molecular dos implantes. Logo foi possível avaliar o compartamento mecânico dos implantes em degradação comparando-os com os requerimentos da aplicação. Pode-se observar que a degradação molecular do implante ao longo dos...
Abstract: The interference screw is the fixation device most selected for Knee ligament reconstruction surgeries. The use of Bioabsorbable polymers in interference screws for this application is increasing due it has advantages like excellent biocompatibility, bioabsorption, good integration between graft / bone and also facility in the surgical revision. The aims of the present study were to develop a bioabsorbable interference screw manufactured by the injection moulding process with two distinct polymeric materials: PLDL, Poly(L,DL-Latic acid) and a composite PLDL + 30% TCP (β Tricalcium phosphate). A program for structural analysis by finite elements was used in the development of the screw design, in the intend to make the best geometry fit for the tool. Trough the study by finite elements simulation it was possible to chose the geometry with higher mechanical resistance taking in the account the torsion effort and analyse the influence of transversals holes in the mechanical tensions made by the torque efforts. After the definition of the best geometry, samples of the screw were manufactured with the two selected polymers, sterilized with ETO (ethylene oxide). Were performed mechanical tests, insertion test and torque to break. The mechanical strenght of the screw was evaluated through the comparison between the values of insertion torque and maximum rupture. In addition, a "in vitro", degradation test was performed over a period of 180 year days. It was observed, the weight loss, mechanical strength of the implants was evaluated, and molecular weight drops of the implants. Therefore it was possible to evaluate the mechanical behavior in degradation and compare with the application requirements. It can be observed that the raise of the molecular degradation of the implant along the months had as result a loss of the mechanical resistance of the screw, ina slowly and gradual way for the PLDL material, yet the composite material (PLDL+TCP)...
Mestre
7
Estambasse, Eduardo Costa. "Análise de materiais para sistemas de fechamento ósseo através da caracterização superficial e comportamento mecânico /". Bauru, 2015. http://hdl.handle.net/11449/132584.
Texto completoResumen
Orientador: Cesar Renato FoschiniBanca: Natal Nerimio Rogone
Banca: Gilberto de Magalhães Bento Gonçalves
Resumo: Neste trabalho busca-se observar um estudo de caracterização mecânica em materiais destinados a implantes, a caracterização superficial dos corpos de provas usinados dos três tipos de materiais utilizados nos implantes para fechamento ósseo titânio grau cinco, titânio grau quatro e aço inox 316 L, estes três tipos de materiais são considerados como biomateriais pois possuem todas as propriedades necessárias para reconstrução óssea, e tem provado ser eficiente para implantes. Este estudo se dará através da aplicação detalhada de ensaios de caracterização superficial e propriedades mecânicas. Um estudo da rugosidade dos materiais antes do implante e a determinação do módulo de cisalhamento e elasticidade utilizando um método não destrutivo foram utilizados. Será apresentado uma síntese dos diferentes tipos de fixação e comparados aos resultados dos ensaios nos materiais. Nos materiais usinados em formatos de discos, foram coletadas imagens num mmicroscópio confocal, e foi realizada análise da superfície com a finalidade de obtenção da rugosidade média quadrática de cada material a fim de identificar a melhor condição de superfície. Uma revisão de literatura fundamentará o estudo proposto
Abstract: In this work the aim is to observe a mechanical characterization study materials for implants, the surface characteristics of the machined test samples of three types of materials used in bone implants for closing five grade titanium, and titanium grade for stainless steel 316 L, there three types of materials are considered as biomaterials because they posses the necessary properties for bone reconstruction, and has proven to be efficient for implants. This study will be through the detailed application of surface characterization and mechanical properties testing. A study of the roughness of the material before implantation and determining the shear modulus and elasticity using a non-destructive method were used. A summary of different types of fasteners and compared to the test results on the materials will be presented. In machined materials dise formats, images were collected on a confocal microscope, and surface analysis was performed for the purpose of obtaining the mean roughness and mean square surface roughness in order to identify the best surface condition. A literature review reasons or the proposed study
Mestre
8
Sridharan, Srinivasan. "Porous plastic implants for bone ingrowth". Thesis, Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/10101.
Texto completo
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Soranz, Filho João Edward. "O uso de implantes orbitários no reparo de cavidades anoftálmicas /". Botucatu : [s.n.], 2011. http://hdl.handle.net/11449/86305.
Texto completoResumen
Orientador: Cláudia Helena PellizonBanca: Silvana Artioli Schellini
Banca: Cláudia Valeria Seullner Brandão
Resumo: Alterações oculares, em especial a perda de volume nas cavidades evisceradas, promovem uma série de modificações ao paciente tanto funcional do órgão quanto psicológica e estética. Uma grande preocupação ao longo do tempo é a procura de um material que possa preencher o volume perdido de forma a dar um maior conforto no ponto de visto psicológico e estético ao paciente. Para contribuir nessa direção, esse trabalho teve como objetivo testar experimentalmente prótese de polietileno granulado de ultra-alto peso molecular, material de baixo custo, em órbitas de coelhos submetidos à evisceração cirúrgica em vários tempos experimentais, onde foram avaliados aspectos macroscópicos e microscópicos e de toxicidade sistêmica do material. Os resultados desse trabalho mostram que o material utilizado no implante de cavidade não apresenta alteração significativa nos parâmetros analisados quando comparados ao grupo controle. Sendo resultados bastante promissores indicando que o implante de polietileno poroso desenvolvido por uma indústria nacional tem alto potencial para se realizar testes em humanos
Abstract: Ocular changes especially the loss of volume in eviscerated cavities promotes several modifications to patients - organ functioning and psychological and esthetical changes. A material that could replace the lost volume in order to guarantee to patients more psychological and esthetical comfort has long been worryingly searched. Contributing in this direction this work aimed at testing experimentally a prosthesis polyethylene granulate of ultra-high molecular weight made of a low cost material to be implanted in orbit of rabbits through surgical evisceration during several experimental times to assess macroscopic and microscopic aspects of systemic toxicity of the respective material. The results show that the material used for the implant of the prosthesis in the cavity does not present significant alteration in the analysed parameters when compared to the control group. Thus, we point with this study promising results indicating that the porous polyethylene implant developed by a national enterprise presents high potential to be tested in humans
Mestre
10
Schultz, Nathaniel David. "A comparison of repeated uniaxial tension and compression on bone-like cells over fourteen days". Master's thesis, Mississippi State : Mississippi State University, 2008. http://library.msstate.edu/etd/show.asp?etd=etd-11072008-150852.
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Santos, Fernanda Henriques dos 1980. "Caracterização de polivinilálcool e polivinilpirrolidona (PVAI/PVP) para reparo de cartilagem articular mandibular". [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263590.
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Orientadores: Cecília Amélia de Carvalho Zavaglia, Vanessa Petrilli BavarescoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: Na área médica, para se desenvolver um dispositivo que funcione como implante, deve-se utilizar materiais que sejam compatíveis para funções específicas do corpo humano, e esses são classificados como biomateriais. Neste trabalho, foram determinados os parâmetros que serão aplicados ao laser de infravermelho (condutividade térmica do material, densidade do material e comprimento de onda do laser) utilizado na máquina de prototipagem rápida, a qual será usada para a fabricação do implante. Este implante será composto por um biomaterial polimérico a base de Polivinilalcool (PVAl) e, terá como objetivo a substituição da cartilagem articular mandibular. Estudos já avaliaram as propriedades mecânicas de hidrogéis poliméricos de PVAl mostrando sua aplicabilidade como reparadores da cartilagem articular em articulação de quadril, porém a articulação mandibular é submetida à aplicações de cargas superiores havendo a necessidade de melhoria de suas propriedades mecânica. A mistura física de dois ou mais polímeros é denominada blenda polimérica e seu objetivo é aperfeiçoar ou modificar as propriedades dos materiais adequando-as para uma aplicação específica. A literatura relata que PVAl e Polivinilpirrolidona (PVP) são polímeros miscíveis entre si e, quando não reticulados são solúveis em água. O PVP é um polímero amorfo e autolubrificante, e por isso, foi escolhido para melhorar as propriedades mecânicas do PVAl. Blendas nas composições de 90:10 de PVAl e PVP respectivamente, reticuladas via laser infravermelho utilizando concentração de 2,5% de termoiniciador cianovalérico foram caracterizadas via Espectroscopia do Infravermelho Médio, Calorimetria Exploratória Diferencial (DSC), Microscopia Eletrônica de Varredura (MEV) e Extração sol-gel. Através desses experimentos foram determinados os parâmetros do laser para posterior utilização na máquina de prototipagem rápida. Foi possível também realizar a cura do material através do laser de infravermelho. A cura foi confirmada através dos outros ensaios realizados
Abstract: In the medical area to develop a device that functions as an implant, one should use materials that are compatible for specific functions of the human body, and these are classified as biomaterials. In this study, we determined the laser parameters that will be applied to the infrared laser (thermal conductivity, material density and wavelength of the laser) in rapid prototyping machine, which will be used to manufacture the implant. This implant is a polymeric biomaterial based on polyvinylalcool (PVAl) and will aim to replace the articular cartilage of the mandible. Studies have evaluated the mechanical properties of polymeric hydrogels PVAl showing its applicability as repairing articular cartilage in hip joint, but the mandibular joint is subjected to loads greater than applications having the need to improve their mechanical properties. The physical mixture of two or more polymers is called polymer blend and its goal is to improve or modify the properties of materials making them suitable for a specific application. The literature reports that PVAl and PVP polymers are miscible and, when not crosslinked, are soluble in water. PVP is an amorphous polymer and selflubricating, and therefore was chosen to improve the mechanical properties of PVAl. Blends in the compositions of 90:10 PVAl and PVP respectively, crosslinked using infrared concentration of 2.5% termoiniciador cianovaléric were characterized by mid-infrared spectroscopy, Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM) and sol-gel fraction. Through these experiments were determined laser parameters for subsequent use in rapid prototyping machine. It was also possible to realize the cure of material through the infrared laser. The cure was confirmed by other tests
Mestrado
Materiais e Processos de Fabricação
Mestre em Engenharia Mecânica
12
Ribeiro, Ana Lúcia Roselino [UNESP]. "Corrosão e tribocorrosão de novas ligas Ti35Nb5Zr e Ti35Nb10Zr em saliva artificial". Universidade Estadual Paulista (UNESP), 2012. http://hdl.handle.net/11449/110659.
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O sucesso dos implantes dentários em longo período depende da interação do biomaterial com o ambiente bucal, a qual envolve reações eletroquímicas, resistência mecânica e desgaste mecânico. Com o intuito de melhorar a resistência mecânica e à corrosão do titânio (Ti), elementos de liga são adicionados, sendo a liga Ti6Al4V a mais comum. Porém, o vanádio e o alumínio são considerados potencialmente tóxicos. Portanto, nos últimos anos, esforços vêm sendo feitos para o desenvolvimento de novas ligas de Ti ultra resistentes e biocompatíveis, a partir do sistema TiNbZr. Assim, o objetivo desse trabalho foi avaliar a corrosão e tribocorrosão das novas ligas Ti35Nb5Zr e Ti35Nb10Zr em saliva artificial a 37°C comparadas à liga comercial Ti6Al4V. Testes de potencial de circuito aberto com o tempo (Ecorr) e espectroscopia de impedância eletroquímica (EIS) foram realizados em função do tempo (0-216h). Testes de tribocorrosão em função de cargas aplicadas (50mN-1N) foram realizados tanto em Ecorr como em potencial anódico aplicado. Como resultados, todas as ligas exibiram aumento de Ecorr com o tempo, indicando crescimento e estabilização do filme passivo. Os experimentos de EIS indicaram que a liga Ti35Nb10Zr possui resistência à corrosão ligeiramente maior que a liga Ti6Al4V, assim como melhor comportamento tribocorrosivo quando realizado com baixa carga. Portanto, o filme passivo formado na liga Ti35Nb10Zr possui melhor resistência à corrosão e ao desgaste devido à presença de Nb2O5 e ZrO2. Porém, o metal base da liga Ti6Al4V apresentou menor desgaste mecânico. Concluindo, a liga de Ti35Nb10Zr é candidata promissora a ser utilizada na fabricação de conjuntos implantes-componentes protéticos.
The long-life success of dental implants relies on the interaction between the biomaterial and oral environment, always involving electrochemical reactions, mechanical stresses and mechanical wear. In order to improve the mechanical strength and corrosion resistance of titanium (Ti), alloying elements are added to it, the most common alloy being Ti6Al4V. However, vanadium and aluminum are known to be toxic. Therefore, in last years, efforts are being made towards the development of new high resistant and biocompatible titanium alloys, namely from the TiNbZr system. Therefore, the aim of this work was to assess the corrosion and tribocorrosion behavior of new Ti35Nb5Zr and Ti35Nb10Zr in artificial saliva at 37°C, in comparison with the commercial Ti6Al4V alloy. Open circuit potential (Ecorr) and electrochemical impedance spectroscopy (EIS) experiments were carried in function of time (0-216h). Tribocorrosion tests were performed at different applied loads (50mN to 1N) both at Ecorr and anodic applied potential. In general, all alloys exhibited an increase of Ecorr with the immersion time, indicating the growth and stabilization of the passive film. The EIS results indicated that Ti35Nb10Zr alloy exhibited slightly better corrosion resistance than Ti6Al4V. Just as better tribocorrosion behavior at low applied loads. Therefore, the passive film formed on Ti35Nb10Zr alloy had better mechanical strength and corrosion resistance due to Nb2O5 e ZrO2. However, the bulk metal of Ti6Al4V suffered less mechanical wear. Concluding, Ti35Nb10Zr alloy appear as promising candidate for dental implant-abutment sets manufacturing.
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Chan, Erwin Pai Hsiung. "Immune reactivity to metal implants". University of Western Australia. School of Anatomy and Human Biology, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0194.
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The use of metals like titanium (Ti) and vanadium (V) are common in many medical implants for orthopaedic and orthodontic purposes. The most frequent cause of implant failure is aseptic loosening, resulting from an inflammatory reaction and increased osteolysis at the bone-metal interface. Currently, the pathophysiological mechanism of aseptic loosening remains poorly understood. One hypothesis suggests the reactivity of immune cells (metal hypersensitivity) towards metal ions released through the biocorrosion of metal implants. This thesis examines the effects of titanium and vanadium ions on various immune cells like monocytes, dendritic cells (DCs) and T-lymphocytes. Thereby investigating the role and mechanism which titanium and vanadium plays in aseptic loosening. Through energy filtered transmission electron microscopy, the accumulation of titanium ions was visualized in human monocyte-derived DCs and T-lymphocytes after 24 hours exposure. Titanium was seen to co-localise with phosphorous-rich regions, like the cell membrane, organelles and nucleus of these cells. Flow cytometry measured changes in the cell surface marker expression of monocytes, osteoclasts, DCs and T-lymphocytes treated with the metals. Monocytes exposed to titanium (IV) showed an increase of Tartate-Resistant Acid Phosphatase (TRAP), important for osteolysis and indicative of differentiation towards an osteoclast-like phenotype. DCs treated with Ti(IV) and vanadium (III) had reduced antigen presenting MHC class II expression, but not a reduced capacity to proliferate non-adherent peripheral blood monocytic cells (naPBMCs). Under the influence of Ti(IV), T-lymphocytes, DCs and monocytes expressed elevated levels of the chemokine receptor, CCR4. This would allow for the migration of CCR4+ cells towards the bone and skin regions. Functional changes were measured with BrdU incorporation proliferation assays, cytokine assays (CBA Kits) and the successful generation of titanium-specific T-lymphocytes from Ti(IV) treated DCs. Ti(IV) specific T-lymphocytes conceptually shows the possible formation of an antigenic titanium-protein complex, which can be recognized by the immune system. DCs treated with Ti(IV) and V(III) were able to cause the proliferation of naPBMCs, even with a reduced antigen presenting capability. However, there was no additional influence of V(III) on the immune response through DCs. Cytokines released by DCs and T-lymphocytes after Ti(IV) treatments showed a skew towards an inflammatory Th1-type response through the release of TGF-! and IL-12p70. Activated T-lymphocytes exposed to Ti(IV) also released RANK-L, which drives osteoclastogenesis and subsequently increased osteolysis. The research supports and suggests an interaction between immune and bone cells where titanium-induced inflammation drives an osteolytic cycle that prevents the integration of metal implants into the bone. Hence, suggesting a mechanism for implant failure through aseptic loosening in patients with titanium-vanadium implants.
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Bastidos, Amanda Marie. "Failure analysis and materials characterization of hip implants". To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2009. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.
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Sidda, Rachel Louise. "Artificial intervertebral discs : mapping of mechanical properties and the effects of microstructure". Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609224.
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Ribeiro, Ana Lúcia Roselino. "Corrosão e tribocorrosão de novas ligas Ti35Nb5Zr e Ti35Nb10Zr em saliva artificial /". Araraquara : [s.n.], 2012. http://hdl.handle.net/11449/110659.
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Resumo: O sucesso dos implantes dentários em longo período depende da interação do biomaterial com o ambiente bucal, a qual envolve reações eletroquímicas, resistência mecânica e desgaste mecânico. Com o intuito de melhorar a resistência mecânica e à corrosão do titânio (Ti), elementos de liga são adicionados, sendo a liga Ti6Al4V a mais comum. Porém, o vanádio e o alumínio são considerados potencialmente tóxicos. Portanto, nos últimos anos, esforços vêm sendo feitos para o desenvolvimento de novas ligas de Ti ultra resistentes e biocompatíveis, a partir do sistema TiNbZr. Assim, o objetivo desse trabalho foi avaliar a corrosão e tribocorrosão das novas ligas Ti35Nb5Zr e Ti35Nb10Zr em saliva artificial a 37°C comparadas à liga comercial Ti6Al4V. Testes de potencial de circuito aberto com o tempo (Ecorr) e espectroscopia de impedância eletroquímica (EIS) foram realizados em função do tempo (0-216h). Testes de tribocorrosão em função de cargas aplicadas (50mN-1N) foram realizados tanto em Ecorr como em potencial anódico aplicado. Como resultados, todas as ligas exibiram aumento de Ecorr com o tempo, indicando crescimento e estabilização do filme passivo. Os experimentos de EIS indicaram que a liga Ti35Nb10Zr possui resistência à corrosão ligeiramente maior que a liga Ti6Al4V, assim como melhor comportamento tribocorrosivo quando realizado com baixa carga. Portanto, o filme passivo formado na liga Ti35Nb10Zr possui melhor resistência à corrosão e ao desgaste devido à presença de Nb2O5 e ZrO2. Porém, o metal base da liga Ti6Al4V apresentou menor desgaste mecânico. Concluindo, a liga de Ti35Nb10Zr é candidata promissora a ser utilizada na fabricação de conjuntos implantes-componentes protéticos.Abstract: The long-life success of dental implants relies on the interaction between the biomaterial and oral environment, always involving electrochemical reactions, mechanical stresses and mechanical wear. In order to improve the mechanical strength and corrosion resistance of titanium (Ti), alloying elements are added to it, the most common alloy being Ti6Al4V. However, vanadium and aluminum are known to be toxic. Therefore, in last years, efforts are being made towards the development of new high resistant and biocompatible titanium alloys, namely from the TiNbZr system. Therefore, the aim of this work was to assess the corrosion and tribocorrosion behavior of new Ti35Nb5Zr and Ti35Nb10Zr in artificial saliva at 37°C, in comparison with the commercial Ti6Al4V alloy. Open circuit potential (Ecorr) and electrochemical impedance spectroscopy (EIS) experiments were carried in function of time (0-216h). Tribocorrosion tests were performed at different applied loads (50mN to 1N) both at Ecorr and anodic applied potential. In general, all alloys exhibited an increase of Ecorr with the immersion time, indicating the growth and stabilization of the passive film. The EIS results indicated that Ti35Nb10Zr alloy exhibited slightly better corrosion resistance than Ti6Al4V. Just as better tribocorrosion behavior at low applied loads. Therefore, the passive film formed on Ti35Nb10Zr alloy had better mechanical strength and corrosion resistance due to Nb2O5 e ZrO2. However, the bulk metal of Ti6Al4V suffered less mechanical wear. Concluding, Ti35Nb10Zr alloy appear as promising candidate for dental implant-abutment sets manufacturing.
Orientador: Luís Geraldo Vaz
Coorientador: Luís Augusto Sousa Marques da Rocha
Banca: Maria da Glória Chiarello de Mattos
Banca: Danilo Luiz Flumignan
Banca: Márcio Luiz dos Santos
Banca: Joni Augusto Cirelli
Doutor
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Carneiro, Lorna Celia. "Surface characteristics and in vitro bio-acceptability of machined and cast pure titanium and titanium alloy". Thesis, Access to E-Thesis, 2003. http://upetd.up.ac.za/thesis/available/etd-09302005-135346/.
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Emerson, Ray Jenkins. "Microbial Adhesion to Medical Implant Materials: An Atomic Force Microscopy Study". Link to electronic thesis, 2004. http://www.wpi.edu/Pubs/ETD/Available/etd-0209104-162349.
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Rosengren, Agneta. "Tissue reactions to biomaterials". Lund : Dept. of Physiology and Neuroscience, Section for Neuroendocrine Cell Biology, and the Dept. of Experimental Research, University Hospital MAS, Lund University, 1997. http://catalog.hathitrust.org/api/volumes/oclc/38986628.html.
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Bock, Eduardo Guy Perpétuo. "Projeto, construção e testes de um dispositivo de assistência ventricular = bomba de sangue centrífuga implantável". [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263298.
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Orientadores: Antonio Celso Fonseca de Arruda, Aron José Pazin de AndradeTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: Uma Bomba de Sangue Centrífuga Implantável (BSCI) foi projetada e construída para assistência ventricular de longa duração no tratamento de pacientes portadores de doenças cardiovasculares. A proposta do projeto foi desenvolver um Dispositivo de Assistência Ventricular (DAV) com custos reduzidos, originalidade de desenho e tecnologia nacional. A geometria do rotor da bomba, aliando um cone em espiral com aletas centrífugas, deu origem ao pedido de Patente de Invenção (PI 0706163-3). O desenvolvimento de seus sistemas propulsores se inclui no Projeto Temático FAPESP nº 2006/58773-1. A metodologia baseou-se em testes individuais dos mancais, atuador e rotor, seguidos de testes do conjunto da BSCI em bancada, com sangue humano e em animais. Foram realizadas simulações numéricas por computador que resultaram no dimensionamento da bomba e definição da sua geometria. Foi testado o atrito nos mancais e os resultados que apresentaram maior durabilidade foram do par alumina-polietileno. Testes em dinamômetro resultaram na caracterização do propulsor eletromagnético, um motor sem escovas trifásico de corrente contínua, e seu controlador eletrônico baseado na técnica de controle sem sensores. Foram realizados testes de hemólise de acordo com as Normas ASTM F1830 e ASTM F1841 para quantificar os danos causados ao sangue pela BSCI e seu índice de hemólise foi de 0,0054 mg/100L, considerado excelente. Testes prospectivos em animais para avaliação do implante resultaram na possibilidade de posicionamento da bomba no tórax ou abdome. Após os testes realizados, a BSCI projetada e construída foi considerada uma opção segura para o tratamento das doenças cardiovasculares. Como trabalhos futuros, serão realizados mais testes em animais para avaliação do funcionamento da BSCI antes dos testes em pacientes
Abstract: An Implantable Centrifugal Blood Pump was developed for long-term ventricular assistance in cardiac patients. In vitro tests were performed, as wear evaluation, performance tests and hemolysis tests in human blood. Preliminary tests were performed with a non-implantable pump in order to properly locate the inlet port. Numerical computational simulations were performed in order to predict its best geometry. Wear evaluations helped to select the best materials for double pivot bearing system proposed to achieve longer durability. Performance tests pointed the best impeller geometry. The Implantable Centrifugal Blood Pump was compared with other two blood pumps. One is a centrifugal blood pump for cardiopulmonary bypass and the other is a similar implantable device called Gyro - Nedo Pump. The proposed implantable centrifugal blood pump showed the best performance. But, its results showed a strong descendant curve in high flow. Other prototype was manufactured with a different inlet port angle to overcome this problem. According to ASTM, the normalized index of hemolysis (NIH) tests were performed "In Vitro" with human blood in closed circuit (mock loop) in normalized conditions, as flow of 5 L/min and total pressure ahead of 100 mm Hg. After six hours, NIH measured 0.0054 mg/100L that can be considered excellent since it is close to the minimum found in literature (between 0.004 g/ 100L e 0.02 g/ 100L). Prior to evaluate performance during "In Vivo" animal studies, anatomical studies were necessary to achieve best configuration and cannulation for Left Ventricular Assistance. Results were considered satisfactory and "In Vivo" tests will be performed looking forward to implant it in patients
Doutorado
Materiais e Processos de Fabricação
Doutor em Engenharia Mecânica
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Saura, Carlos Eduardo 1958. "Metodologia para desenvolvimento de implantes cranianos personalizados". [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265851.
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Orientador: Cecilia Amélia de Carvalho ZavagliaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: Esta tese demonstra os benefícios relacionados ao uso efetivo de uma metodologia que visa guiar todo processo de cranioplastia, utilizando-se de implantes personalizados para regenerar falhas cranianas. Sabe-se que diferentes técnicas de implante, geralmente atreladas a casos médicos específicos, têm sido aplicadas já há vários anos. Isso acarretou uma grande e valiosa evolução nesta área, porem também gerou dúvidas sobre qual técnica seria a mais eficaz a ser empregada em cada caso. A metodologia aqui explanada visa auxiliar desde o diagnóstico, passando pela coleta de imagens médicas, elaboração do modelo tridimensional do paciente contendo sua falha óssea, modelamento do implante, criação física do mesmo através do uso da Manufatura Aditiva (MA) e finalmente a aplicação do implante no paciente. Esta metodologia é aplicável aos implantes personalizados metálicos, poliméricos ou cerâmicos, e direcionados para serem executados pela tecnologia de MA que também é conhecida como prototipagem rápida. Na origem do processo está a captura de imagens médicas do crânio e da falha óssea através de tomografia computadorizada. As fatias tomográficas são transformadas em um modelo tridimensional no sistema InVesalius® (CTI ¿ Brasil) e os arquivos neles criados são transferidos para um programa específico utilizado na MA chamado Magics RP ¿, nele então o biomodelo tridimensional é analisado e preparado para execução de um modelo físico. Na criação do implante em caso de falhas pequenas ou médias que estão alocadas totalmente em um dos hemisférios do crânio pode-se usar apenas o Magics RP ¿. Em casos de falhas grandes laterais (que invadem o hemisfério oposto) ou frontais, utiliza-se o programa de CAD, neste caso o SolidWorks ¿, no qual são trabalhadas superfícies e sólidos com o objetivo de reconstruir fielmente o perfil craniano através do implante que está sendo desenvolvido. Os resultados obtidos com o uso da metodologia são implantes de adequação perfeita, diminuição no tempo de cirurgia e rápida recuperação e integração social do paciente. Conclui-se que o grande benefício de se ter uma Metodologia para Desenvolvimento de Implantes Cranianos Personalizados é que esta orienta através de um conjunto de diretrizes as equipes multidisciplinares compostas de cirurgiões, radiologistas, técnicos e engenheiros, estejam orientadas e preparadas a atender a crescente necessidade de implantes cranianos personalizados
Abstract: This thesis demonstrates the benefits related to the effective use of a methodology that aims to guide the whole process of cranioplasty, using custom implants to regenerate cranial defects. Known is that different implant techniques, usually linked to specific medical cases, has being applied for several years. This led to large and valuable developments in this area, but also raised questions about which one would be the most effective technique employed in each case. The methodology here explained aims to give an assistance from diagnosis, through the collection of medical imaging, three-dimensional model of patient preparation containing your bone gap, modeling of the implant, creating physically the implant with the Additive Manufacturing (MA) and finally the application of implant into the patient. This methodology is applicable to custom metallic implants, polymeric or ceramic and produced with MA technology, which is also known as rapid prototyping. The process is capturing medical images of skull and bone gap through computerized tomography. Tomographic slices are transformed into a three-dimensional model in InVesalius ® system (CTI-Brazil) and the files in them created are transferred to a specific program used in MA, called Magics RP ¿, it then the three-dimensional biomodelo is parsed and prepared for execution of a physical model. In the creation of the implant in case of small or medium failures allocated fully in one of the skull hemisphere can only use the Magics RP ¿. In cases of large lateral faults (invading the opposite hemisphere) or front, we use CAD program, in this case the SolidWorks ¿, in which we work with surfaces and solids in order to be faithfully reconstruct cranial profile through the implant is being developed. The results obtained with the use of the methodology are perfect adequacy implants, decreased at the time of surgery and speedy recovery and social integration of the patient. Concluded is that the major benefit of having a methodology for developing Custom Cranial Implants is that this leads you through a set of guidelines the multidisciplinary teams composed of surgeons, radiologists, technicians and engineers, are targeted and prepared to meet the growing need for custom cranial implants
Doutorado
Materiais e Processos de Fabricação
Doutor em Engenharia Mecânica
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Conde, Mir Isabel. "Compatibilitat clínica entre marcapassos cardíacs i aparells electrònics odontològics: Estudi in vivo". Doctoral thesis, Universitat de Barcelona, 2018. http://hdl.handle.net/10803/663120.
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INTRODUCCIÓ: Els implants actius cardíacs, que inclouen marcapassos i desfibril·ladors automàtics implantables, estan indicats en el tractament d'arrítmies i en determinats casos d'insuficiència cardíaca. L’ús d’aquests dispositius és cada vegada més freqüent i, per tant, és habitual que els professionals de l’odontoestomatologia haguem de tractar pacients que en son portadors. Tradicionalment, l'ús de determinats instruments odontològics ha estat prohibit en portadors d’implants actius cardíacs per evitar possibles interferències electromagnètiques que poguessin alterar el seu funcionament. No obstant això, els marcapassos actuals compten amb mecanismes de protecció que minimitzen aquest risc i recents estudis in vitro apunten que, a la distància d’ús habitual, no haurien d’interferir amb els dispositius cardíacs. Davant la controvèrsia respecte als efectes dels aparells odontològics sobre els marcapassos, es va plantejar un estudi in vivo, a la Unitat d’Arrítmies de l’Hospital Clínic, per valorar-ne la seva compatibilitat en condicions habitual d’ús clínic. MATERIAL I MÈTODE: Seixanta-sis pacients consecutius portadors de marcapassos de diferents marques/models i modes de programació van ser inclosos a l’estudi durant la seva visita de control del marcapassos. Es van incloure només aquells pacients no dependents del marcapassos, és a dir, amb un ritme intrínsec propi superior a 40 batecs/min. Mentre els pacients estaven monitoritzats a través del programador del dispositiu, es van realitzar els tests amb els tres aparells odontològics seleccionats: ultrasò dental, localitzador electrònic d’àpex i pulpòmetre. Durant la realització dels tests s’obtenia, a través del programador, el registre imprès de l’electrocardiograma de superfície, l’electrograma intramiocàrdic i el canal de marques. El mode d’aplicació dels aparells odontològics va ser simulant el seu ús clínic i amb dos modes d’aplicació diferents: continu -on- i discontinu -on/off-. Paràmetres dels marcapassos com: sensibilitat, llindar i impedància, van ser registrats abans i després de la realització dels tests amb els aparells odontològics. Les interferències van ser classificades en primer lloc dicotòmicament com: “soroll detectat” o “no soroll detectat”. En cas de que es detectés soroll, es determinava si hi havia o no conseqüències en el funcionament dels marcapassos com: inhibició, canvi de mode o reset. RESULTATS: Cap dels aparells odontològics va produir cap interferència sobre els marcapassos analitzats, ni tan sols interferències lleus tipus “soroll”, en cap dels dos modes d’aplicació. Cap marcapassos va veure alterat el seu funcionament. La comparació de les mitjanes dels paràmetres dels marcapassos abans i després de la realització dels tests, per mitjà del test t de Student per dades aparellades, va permetre corroborar que no s’havia produït cap alteració en els dispositius. Els tres aparells odontològics van produir, en alguns casos, artefactes en el registre electrocardiogràfic, sense que això tingués cap repercussió en l’electrograma intramiocàrdic i en el funcionament dels dispositius cardíacs. CONCLUSIONS: Els instruments odontològics testats són compatibles amb els marcapassos analitzats, ja que in vivo i a la distància clínica habitual de treball, no van alterar el funcionament d’aquests dispositius cardíacs. Totes les marques i tots els models de marcapassos analitzats es van mostrar igual d’inalterables a l’exposició de l’ultrasò dental, el localitzador electrònic d’àpex i el pulpòmetre. El moment de connexió/desconnexió -on/off- dels instruments odontològics testats no es va poder considerar com un instant crític a l’hora d’afavorir l’aparició d’interferències. Tots els aparells odontològics examinats van mostrar capacitat de produir, durant la seva utilització, algun tipus d’artefacte, en el registre electrocardiogràfic. Conseqüentment, els resultats del nostre estudi qüestionen l’ECG com una prova fiable per detectar veritables interferències induïdes sobre els marcapassos. Els resultats de l’estudi ens van permetre refutar la hipòtesi nul·la en favor de l’alternativa i demostrar que els aparells odontològics testats, a distàncies habituals d’ús clínic, són compatibles amb els marcapassos.Patients with pacemakers are increasingly frequent in dental practice. Dental treatment commonly involves the use of electronic instruments which might cause electromagnetic interferences. As a result, manufacturers discourage their use in patients with cardiac implanted electronic devices. However, pacemakers now have better shielding, interference rejection filters, noise protection algorithms and bipolar configuration that make them more compatible with the electronic / electromagnetic equipment used in the dental setting. Available literature about the effect of these dental instruments on the pacemaker’s function is controversial and in-vivo investigations are scarce. This study aimed to evaluate in-vivo the effect of an ultrasonic dental scaler, an electric pulp tester and an electronic apex locator on patients with different pacemaker brands and configurations. A total of 66 non-pacemaker-dependent patients were included in the present study during their regular follow-up visit at the electrophysiology unit. Each dental instrument was tested in two different application modes – pulse (on/off) and continuous (on) – to determine whether the moment when electronic dental tools were switched on and off was a critical stage in the production of electromagnetic interferences. Conditions in the dental setting were replicated as closely as possible. The closest tooth to the pacemaker was selected for the tests. A total of 24 different models of pacemakers from different manufacturers were tested. No changes were made in the pacemaker program setting established for each patient. Different types of electromagnetic interferences were initially classified dichotomously: noise detected or no noise detected. In case of any noise, we discriminated between no consequence for pacemaker function and consequences for the pacemaker function: pacing inhibition, change to asynchronous mode or electric reset. Artifacts affecting the surface electrocardiogram were also registered. No interferences were detected in the intracardiac electrogram of any patient while using dental equipment. No abnormalities in pacemaker pacing and sensing function were observed. Artifacts affecting the surface electrocardiogram without affecting the intracardiac electrogram were found in a large number of patients, especially while using the ultrasonic dental scaler. Under real clinical conditions, none of these electronic dental instruments interfered with pacemaker function.
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Archibald, Petra A. "Characterization of the metabolic and secretory behavior of suspended free and entrapped cell laden microcarriers in fed-batch cultures". Thesis, Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/11791.
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Hudgins, Robert Garryl. "Development and characterization of a prosthetic intervertebral disc". Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/20675.
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Tang, Wing-kit. "In vitro kinematics of the lumbar facet joints for the development of a facet fixator". Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B43572066.
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Park, Hyuen Me (Mia) Park. "Numerical and experimental analysis of stress behavior of plasma-sprayed Bioglass on titanium /". Full text open access at:, 1996. http://content.ohsu.edu/u?/etd,587.
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Baker, Carrie E. "Auxetic Spinal Implants: Consideration of Negative Poisson's Ratio in the Design of an Artificial Intervertebral Disc". University of Toledo / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1302099679.
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Emerson, Ray Jenkins. "A nanoscale investigation of pathogenic microbial adhesion in biomaterial systems". Link to electronic dissertation, 2006. http://www.wpi.edu/Pubs/ETD/Available/etd-042706-075421/.
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Rajaratnam, Rema Antonette Prince of Wales Clinical School UNSW. "The effects of polyethylene wear debris and oestrogen deficiency on fracture healing in a rodent model". Awarded by:University of New South Wales. Prince of Wales Clinical School, 2005. http://handle.unsw.edu.au/1959.4/23351.
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Patients who suffer from severe joint destruction caused by arthritis often undergo total joint arthroplasty (TJA). A major limitation of this treatment and common long-term complication is the development of aseptic loosening of the prosthesis in as many as 20% of patients. The current paradigm to explain aseptic loosening proposes that wear debris generated from the prosthesis initiates a macrophage-mediated inflammatory response by resident macrophages, leading to osteoclast activation and bone resorption at the implant interface. This can then lead to the development of a peri-prosthetic fracture. The principal aim of fracture healing is to restore the bone to its original form and strength. However, this ultimate goal can be altered if the healing is impaired. This impairment may be due to bone disease (osteoporosis) or even the introduction of a foreign material such as PE wear debris that could have migrated from the articulating surface to the fracture site. A standard closed unilateral fracture of the right femur was performed in both normal and oestrogen deficient rats following fixation with a k-wire. Ceridust (PE wear debris) was combined with hyaluronic acid and saline and injected directly into the fracture site. Femurs were assessed using radiographs, histology and immunohistochemistry. Histological analysis revealed that complete remodelling was achieved in all control groups by 6 weeks post-fracture with mechanical strength returning to normal values. The mechanical properties of the fractures were not influenced by the presence of PE wear debris in the dose and timing examined. Histology and immunohistochemistry however, did reveal a local effect of the presence of PE wear debris. The histology adjacent to the PE particles was inferior to the controls but did not manifest itself in a reduction in the mechanical properties except in the oestrogen deficient bone at 6 weeks post-fracture. The levels of MMP-1 and TNF-?? correlated to the presence of PE particles. In this thesis, I have shown the mechanism by which bone remodelling in fracture healing could be retarded due to the presence of PE wear debris, by increased matrix degradation in both normal and oestrogen deficient animals.
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Yang, Jing y n/a. "The roles of siderophores in bacterial adhesion to metals and iron transport". University of Otago. Department of Chemistry, 2009. http://adt.otago.ac.nz./public/adt-NZDU20090825.144153.
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Siderophores are a series of important iron chelators secreted by many bacteria that normally have high affinity of iron ions and contain hydroxamate, catecholate and carboxylate and other ligand groups. These organic ligands play significant roles in bacterial metabolism: solubilising iron (III) from environments, enabling iron uptake and acting as a cell-signalling molecule to control gene expression. Recent observations of initial stages of Pseudomonas aeriginosa biofilm formation on metal oxides surfaces indicate that siderophores may also facilitate bacterial adhesion to metals. However, details of how siderophores interact with metal surfaces and the relationship of their chemical nature with bacterial adhesion were not fully understood. To test the generality of bacteria attachment to metals via siderophores, the adsorption behaviour of siderophores and their functional ligands groups on particle films of metal oxides were investigated with in-situ ATR-IR spectroscopy.
In this study, nanoparticle films of titanium oxide, boehmite, iron oxide and chromium oxyhydroxide were prepared as substrates to simulate titanium, alumnium, stainless steel surface and more detailed work were carried out on titanium dioxide. Monohydroxamic acids (acetohydroxamic acid, N-methylformohydroxamic acid, N-methyl-acetohydroxamic acid and 1-hydroxy, 2-piperidone) and catechol and catechol-like (L-dopa and esculetin) ligands were selected as modelling compounds for the most frequently occured functional groups in natural siderophores. IR spectra of these ligands in aqueous solution and adsorbed on TiO₂ were obtained with a flowing cell system fit to a horizontal accessory by in situ ATR-IR spectroscopy and interpreted based on vibrational mode analysis with density function theory. Results show that all these ligands can form surface complexes with metal surfaces and possible adsorption modes of these molecules were discussed. The pH dependence of absorbance of IR absorption of these adsorbed ligands showed that most of the ligands exhibited maximium adsorption to TiO₂ at about pH 8, only N-methylformohydroxamic acid, 1-hydroxy, 2-piperidone groups having maximum absorption at pH~3 and pH~6.
Infrared spectroscopic studies of adsorbed siderophores (desferroximme B, enterobactin and pyoverdine) were also carried out in variation of concentration and pH. Possible adsorption modes of these iron scavenger ligands on TiO₂ and other metal oxides were discussed. Results showed that all these ligands adsorbed on metal oxide surfaces and form surface complex via hydroxamate or catecholate lignd groups which confirm the generality of siderphore-metal bond formation.
Siderophore based-bacterial adhesion to metals of was conducted with Pesudomonas aeruginosa and E. coli strains on titanium oxide and iron oxide films. These observations support that siderophore play a significant role in bacterial adhesion to metals. Further work needs to be carried out on the wider involvement of siderophores in bacterial adhesion initiation to metals and siderophore-mediated iron transport.
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Tang, Wing-kit y 鄧穎傑. "In vitro kinematics of the lumbar facet joints for the development of a facet fixator". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B43572066.
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Pecoraro, Michael A. "Characterization of the effects of the human head on communication with implanted antennas /". Online version of thesis, 2010. http://hdl.handle.net/1850/11698.
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Pino, Monica. "Apatite deposition on NaOH-treated HDPE, PEEK and UHMWPE films for sclera materials in artificial cornea implants". Thesis, University of Glasgow, 2010. http://theses.gla.ac.uk/1896/.
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Corneal disease is the second most common cause of blindness in the word. It is estimated that 45 million people worldwide are bilaterally blind and 10 million are affected by corneal blindness. Corneal blindness mostly affects the population in the equatorial zone, due to the high exposure to UV light. Corneal grafting presents complications such as rejections and the lack of donor material and resources. Conventional cornea grafting (keratoplasty) is not advised for patients with bilateral corneal blindness or for those who suffer from a range of clinical problems including tear deficiency, chemical burns and uncontrollable intraocular pressure. At present, an artificial cornea, i.e. a keratoprosthesis (KRPO), is the only alternative to keratoplasty (corneal donor transplantation). Cornea implants consist of a clear optic part and a surrounding ring known as the skirt, which needs to integrate with the sclera of the eye. Currently used skirt materials lead to poor tissue integration, a major failure of cornea implants. Better integration may be achieved when using a bioactive skirt material, which adapts to the metabolic activity of the cornea. For this purpose, high density polyethylene (HDPE), polyether ether ketone (PEEK) and ultra-high molecular weight polyethylene (UHMWPE) films provide interesting possible alternatives, if they can be rendered bioactive. This study investigated the potential of using surface modified polymer films to fabricate the skirt. To improve bioactivity of the materials a two-step treatment using chemical surface modification (immersion in NaOH) and formation of apatite layers from Simulated Body Fluid (SBF) was applied. The effectiveness of the different molarity of the NaOH on the formation of the bioactive layer was investigated. Results showed that with an increase in NaOH concentration the wettability improved but also some changes to the topography (increase/decrease of roughness) of the polymers were observed. Moreover, 10M NaOH treatments resulted in more rapid formation of the apatite layer when compared with a non-treated and lower molarity solution. As immersion time in SBF increased, further nucleation and growth produced a thicker apatite layer which can be expected to be highly bioactive. Interestingly, the apatite growth is dependent on both the concentration of NaOH solution and the structure of the polymer surface. It was concluded that hydroxyapatite layers were formed on HDPE, PEEK and UHMWPE films after they were incubated in 1.5 SBF, which promises to render such thin-film structures bioactive – a necessity if they are to be integrated into artificial cornea. The Ca/P molar ratio of the apatite deposited on the polymers increases with NaOH strength and SBF incubation time. The favourable effect of NaOH on apatite formation may at least partly be attributed to an increased wettability of the polymer films after such treatment, as well as to the modified topography. The apatite layer contained phosphate and carbonates ions, providing potentially good in vitro bioactivity on polymeric films. The inorganic layers are chemically stable as the calcium deposited on the films did not dissolve fully when immersed in water for one week. This demonstrates that polymer films can be rendered bioactive, using the described approach, hence providing potential materials suitable for artificial cornea implants.
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Kriebel, Andreas [Verfasser], Jörg [Akademischer Betreuer] Mey y Hermann [Akademischer Betreuer] Wagner. "Construction and biological testing of artificial implants for peripheral nerve repair / Andreas Kriebel ; Jörg Mey, Hermann Wagner". Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1129875660/34.
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Kandasamy, Sivakumar P. "In vivo monitoring of collagen-sponge remodeling using MRI". Worcester, Mass. : Worcester Polytechnic Institute, 2007. http://www.wpi.edu/Pubs/ETD/Available/etd-032607-091929/.
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Fang, Mimi. "The role of phospholipase d in osteoblasts in response to titanium surfaces". Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26462.
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Thesis (M.S.)--Biomedical Engineering, Georgia Institute of Technology, 2009.Committee Chair: Boyan, Barbara; Committee Member: Eskin, Suzanne; Committee Member: Lobachev, Kirill; Committee Member: Schwartz, Zvi. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Sonalkar, Prachi Santosh. "Development of an Implantable Data Acquisition System". See Full Text at OhioLINK ETD Center (Requires Adobe Acrobat Reader for viewing), 2005. http://www.ohiolink.edu/etd/view.cgi?toledo1122671274.
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Thesis (M.S.B.)--University of Toledo, 2005.Typescript. "A thesis [submitted] as partial fulfillment of the requirements of the Master of Science degree in Bioengineering." Bibliography: leaves 73-75.
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Feldt, Christian E. "Stress shielding minimized in femoral hip implants a finite element model optimized by virtual compatibility". Doctoral diss., University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4892.
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Bone mechanics and traditional implant materials produce a recurring problem for patients of total hip arthroplasty (THA): the bone is "shielded" from the loading it has become accustomed to over many years of development. Bone adheres to what is called "Wolff's Law", meaning it is an adaptive structure which adjusts its geometry based on the loads experienced over its life (Pearson; Goldstein). As the new femoral hip implant transmits reduced stresses to the remaining bone, bone tissue atrophies at the interface, permitting loosening of the implant, pain, and thereby obliging additional surgery to correct the issue (Meade). In the present work, a methodology is endeavored for creating an innovative design for femoral hip implants. The approach uncouples the finite element implant model from the bone model, in order to focus solely on expected behavior within the implant while considering the varying material behavior in unique directions and locations. The implant's internal geometry is optimized in order to better match typical, intact bone conditions. The eventual design reduces extreme changes in stresses within remnant bone such that the implant will remain implanted for greater periods of time without additional surgical attention.ID: 030423147; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (Ph.D.)--University of Central Florida, 2011.; Includes bibliographical references (p. 86-91).
Ph.D.
Doctorate
Mechanical, Materials, and Aerospace Engineering
Engineering and Computer Science
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Bell, Bryan Frederick. "Mechanisms regulating osteoblast response to surface microtopography and vitamin D". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31711.
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Thesis (Ph.D)--Materials Science and Engineering, Georgia Institute of Technology, 2010.Committee Chair: Barbara Boyan; Committee Member: Andres Garcia; Committee Member: Anthony Norman; Committee Member: Nael McCarty; Committee Member: Zvi Schwartz. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Kinney, Timothy. "A comparison of modeling techniques using the finite element method to determine local displacements in a human hip /". Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/5987.
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Thesis (M.S.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on April 14, 2008) Includes bibliographical references.
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Zhang, Xing. "Electrospun tri-layer micro/nano-fibrous scaffold for vascular tissue engineering". Birmingham, Ala. : University of Alabama at Birmingham, 2008. https://www.mhsl.uab.edu/dt/2010r/zhang.pdf.
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Kazemian, Marvi Salman. "Biomechanical rationale of episiotomy for removal of femoral components: In vitro investigation for removal of well-fixed implants. An artificial implantation model for the simulation of implant-bone interface". Thesis, Queensland University of Technology, 2018. https://eprints.qut.edu.au/115801/1/Salman_Kazemian%20Marvi_Thesis.pdf.
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Removal of well-fixed femoral components during revision of hip arthroplasty is generally challenging for the surgeon. It can be associated with an increase in the length of procedure and operative complications. The easier extraction of femoral components and expansion of the proximal femur using episiotomy as a single posterior longitudinal split osteotomy was therefore described. In this research, we designed an in vitro protocol to simulate the extraction of press fit implants using an episiotomy in the long axis of the femur analogue to remove the implant. The mean extraction force after performing the episiotomy was significantly lower compared with similar constructs without performing the episiotomy. This paper presents an artificial model for the simulation of implant-bone interface and investigates episiotomy as a method for the extraction of well-fixed implants. It can provide information that may help in subsequent orthopedic techniques in revision surgery.
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Hung, Lie-chung. "Electropolishing of Ti-6A1-4V surgical implant alloy and its effect on corrosion behavior". Thesis, Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/20731.
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Sharpe, Alton Russell. "Functional validation of a novel technique for assembling high density polyimide cochlear implants". Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45741.
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It has been hypothesized that increasing the number of active sites on a cochlear implant electrode array will enable the recipient to distinguish a higher number of pitch precepts, thus creating a more natural sound. While DSP processing strategies for cochlear implants have evolved significantly to address this, technology for the actual electrode array has remained relatively constant and limits the number of physical electrodes possible. Previous work introduced the concept of using Thin-Film Array (TFA) technology to allow for much higher site densities, although the original devices proved unreliable during surgical insertion tests. This work presents a new method of combining polyimide-based TFA's with supporting silicone insertion platforms to create assembled electrode arrays that are a more viable option for surgical insertion. The electrical and mechanical properties of these assemblies are investigated with physical deformation tests and finite element analysis in COMSOL to quantify how they will perform upon insertion into the cochlea, and the preliminary results of a surgical insertion study into human cadaveric temporal bones will be discussed.
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Zavaglia, Felipe de Carvalho. "Síntese, caracterização e processamento de beta fosfato tricálcico para manufatura de implantes personalizados". [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263612.
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Orientadores: Maria Clara Filippini Ierardi, André Luiz Jardini MunhozDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
Made available in DSpace on 2018-08-18T11:48:55Z (GMT). No. of bitstreams: 1 Zavaglia_FelipedeCarvalho_M.pdf: 14473856 bytes, checksum: 25fac84e52ec20bec15f8b33d830a26a (MD5) Previous issue date: 2011
Resumo: Os biomateriais vêm sendo desenvolvidos e utilizados há muito tempo, e, uma questão relevante a se observar, é a conformação destes materiais para a confecção de produtos. Um novo conceito surge com a prototipagem rápida. Como os componentes do organismo humano são únicos e distintos, as tecnologias modernas de prototipagem rápida e personalização de implantes se destacam em importância. O uso de prototipagem rápida está relacionado normalmente à produção indireta de próteses e outras soluções médicas; no entanto, estudos recentes tem sido feitos com o objetivo de se utilizar as técnicas de prototipagem rápida diretamente com os biomateriais. O objetivo do presente pesquisa foi sintetizar e caracterizar a biocerâmica de beta fosfato tricálcico (ß-TCP) para aplicações em três tipos de casos de implantes. O procedimento experimental constou da síntese do ß-TCP e caracterização através de microscopia eletrônica de varredura, avaliação da distribuição granulométrica, espectroscopia de fluorescência de raios X e difração de raios X. Foram preparados, com essa biocerâmica, implantes de formatos simples (como pequenos discos), através da conformação por prensagem uniaxial e sinterização. A preparação dos grânulos de ß-TCP e ligantes foi feita de duas maneiras: manualmente e através de equipamento spray dryer. Após essa preparação dos grânulos foi realizada a prototipagem rápida, com sucesso, de pequenos corpos de prova em equipamento 3D Printer. O ß-TCP sinterizado também foi utilizado, através da técnica PVD (deposição física a vapor) para revestir implantes macro porosos de titânio metálico, obtidos por outro equipamento de prototipagem rápida (sinterização de metais direta a laser). Os resultados obtidos neste trabalho foram satisfatórios, demonstrando que as técnicas desenvolvidas de utilização do ß-TCP pode levar a obtenção de implantes úteis no tratamento de pessoas com problemas de pequenos defeitos ósseos
Abstract: Biomaterials have been developed and used for a long time, and a relevant question is about conformation of these materials for products confectioning. A new concept arises with rapid prototyping. Due to the components of human organism being single and distinct, modern techniques of rapid prototyping and implants personalization stand highly. The use of Rapid prototyping is usually related to indirect production of prosthesis and other medical solutions, however, recent studies have been done with the goal to use rapid prototyping techniques directly with biomaterials. The present research goal was to synthesize and characterize beta tricalcium phosphate (ß-TCP) for application in three types of implants. The experimental procedure consisted in the synthesis of ß-TCP and its characterization by scanning electronic microscopy, granulometric distribution evaluating, x-ray fluorescence spectroscopy and X-ray diffraction. Simple structures were prepared with this bioceramic by axial pressing and sintering. The preparation of ß-TCP granules with binder was done in two ways: manually and by spray drying equipment. After granules preparation, rapid prototyping was performed with success of small specimens with a Zcorp 3D Printer equipment. The sintered ß-TCP was also used for coating macro porous metallic titanium implants obtained by other rapid prototyping equipment, (direct metal laser sintering) using PVD technique (physical vapor deposition). The present results were satisfactory, showing that the techniques developed for ß-TCP can lead to useful implants for small bone defects
Mestrado
Materiais e Processos de Fabricação
Mestre em Engenharia Mecânica
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Brumby, Scott Andrew. "The effect of surface roughness and a collar on fixation of cemented femoral stems in vivo /". Title page, table of contents and summary only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phb8934.pdf.
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Ribera, Puig Alba. "Orthopaedic device-related infections: some thoughts on management and antimicrobial efficacy from a clinical and experimental perspective". Doctoral thesis, Universitat de Barcelona, 2017. http://hdl.handle.net/10803/587107.
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Orthopaedic device-related infections represent a health care problem of first magnitude due to the increasing incidence, complexity of management, and elevated cost. These device related infections have etio-pathogenic features that involve the participation of bacteria in the stationary growth phase as well as mature biofilms, which makes their diagnosis and treatment more challenging. Several studies have been performed to ameliorate the present guidelines. Nevertheless, there are still many points of uncertainty and many relevant clinical questions remain unanswered. This thesis explores some of these unanswered questions in the field of orthopaedic device related infections from the perspective of an infectious diseases specialist.
A. On the management of orthopaedic device-related infections
A.1. Diagnostic aspects of PJI
• Aim 1: to analyse the microbiological and clinical findings in patients with suspected prosthetic joint aseptic loosening, and to compare them to patients with chronic PJI
Conclusions:
1.1 Several patients with suspected prosthetic aseptic loosening have misdiagnosed PJI or some microorganisms in their samples.
1.2 Sonication samples provide additional microbiological information that should help clinicians with the diagnosis of delayed low-grade infections that mimic natural aseptic failure.
1.3 Clinical parameters that determine the final prosthesis removal are correlated with the number of positive peri-prosthetic samples.
A.2. Surgical management of PJI
• Aim 2: to evaluate the risk of re-infection following one-stage and to-stage surgical revision with hip PJI
Conclusions:
2.1 The one-stage revision strategy may be as effective as the two-stage revision strategy.
B. On the assessment of antimicrobial efficacy for the treatment of orthopaedic devicerelated infections
B.1. Infections by Streptococcus spp
• Aim 3: to assess the efficacy of adding rifampicin to β-lactams for the treatment of streptococcal PJI managed with implant retention, and its impact on the prognosis
Conclusions:
3.1 For the largest case series of stretopcoccal PJI managed with DAIR, this pathology showed a not-so-good prognosis as expected.
3.2 The treatment with β-lactams seems ideal for fighting the planktonic component of streptococcal PJI; the addition of rifampin some days or weeks after debridement could have a role in the antibiofilm profile to improve the current modest outcomes.
3.3 A concomitant and optimal surgical procedure is advised, following IDSA criteria and ensuring the exchange of removal components during the debridement. Similar prognosis results were observed when the IDSA criteria for DAIR were cutoff at the third month of revision.
B.2. Infections by MDR Gram-negative bacilli
B.2.1 The use of β-lactams in continuous infusion
• Aim 4: to standardize a measurement procedure based on UHPLC-MS/MS for the simultaneous determination of multiple β-lactam concentrations in human plasma
Conclusions:
4.1 The development of a single UHPLC-MS/MS method for the simultaneous measurement of multiple β-lactam concentrations in human plasma enable the applicability of this method to routine clinical practice and the validation of an easy-to use equation for clinical use.
• Aim 5: to evaluate the efficacy and safety of β-lactams in continuous infusion for difficult-to-treat osteoarticular infections caused by Gram-negative bacilli, and to validate an easy method for clinical use
Conclusions:
5.1 The use of β-lactams in continuous infusion is safe and effective, and may recover previously resistant strains that became susceptible in terms of their pharmacodynamic parameters. Lower doses could be used by BL-CI for susceptible strains.
5.2 A simple equation could help clinicians to estimate the β-lactams continuous infusion dosage and its plasma levels in the early hours of treatment.
B.2.2 The use of antibiotic combinations with colistin
• Aim 6: to evaluate the benefits of the combination of colistin and β-lactams when treating patients with MDR Pseudomonas aeruginosa infections
Conclusions:
6.1 Current recommendations should consider the combination of low-dose colistin with β-lactams as an optimized treatment for osteoarticular infections caused by MDR P.aeruginosa.
6.2 This antibiotic combination is essential for achieving positive outcomes for these difficult-to-treat infections.
• Aim 7: to study the effect of adding colistin to β-lactams against ESBL-producing klebsiella pneumoniae biofilm in an in vitro experimental model
Conclusions
7.1 As expected, colistin in monotherapy was ineffective against biofilm-embedded bacteria and resulted in the emergence of colistin resistant strains.
7.2 Meropenem in monotherapy and its combination with colistin achieved rapid killing rates that were maintained until the end of treatment. However, only the combination showed bactericidal activity in one of the tested strains of ESBL-producing Klebsiella pneumoniae and its effect was more pronounced under conditions that produced a greater biofilm. The combined therapy avoided the emergence of colistin-resistant strains.
7.3 Our preliminary results may indicate a slight overall superiority in vitro of adding colistin to β-lactams against carbapenem-susceptible ESBL-producing K. pneumoniae.Les infeccions osteoarticulars relacionades amb implants ortopèdics són un problema de salut de primera magnitud: per la seva incidència creixent, la seva complexitat i l’alt cost sanitari. Suposen un gran repte per l’especialista en malalties infeccioses, principalment per les seves particularitats etio-patogènicas amb participació de bacteris en fase estacionària de creixement i la formació de biofilm. Els objectius d’aquesta tesi pretenen explorar alguns aspectes no resolts sobre el maneig i la eficàcia antimicrobiana en el marc de la infecció osteoarticular relacionada amb l’implant. Al través de 7 treballs s’han desenvolupat els següents punts: • Estudi de les característiques clíniques i microbiològiques dels casos d’afluixament asèptic protèsic sotmesos a revisió, amb l’objectiu d’entendre millor aquesta entitat (interpretació dels cultius positius aïllats). • Estudi comparatiu del maneig quirúrgic de la infecció protèsica crònica: recanvi en un o dos temps. • Estudi de la infecció protèsica estreptocòccica manejada amb desbridament, antibiòtics i retenció de l’implant (DAIR); amb l’objectiu d’avaluar el pronòstic d’aquesta entitat i els factors que poden millorar la seva taxa de curació. • Estudi sobre l’ús de betalactàmics en infusió continua en les infeccions osteoarticulars relacionades amb implants causades per BGN, amb els objectius: 1) estandarditzar un procediment basat en UHPLC-MS/MS para la determinació dels nivells plasmàtics de betalactàmics, 2) validar una equació senzilla per estimar la dosis de betalactàmics òptima en perfusió continua i els nivells plasmàtics. 3) avaluar la seguretat i eficàcia antimicrobiana de l’ús de betalactàmics en infusió continua. • Estudis sobre l’eficàcia d’afegir colistina al tractament amb betalactàmics en el maneig d’infeccions gram-negatives multiresistents: 1) estudi clínic , 2) model in vitro per la formació de biofilm. Les principals troballes: • Alguns casos amb sospita d’afluixament protèsic asèptic són realment infeccions o presenten microorganismes aïllats sobre la superfície de l’implant. • L`estratègia de revisió protèsica pel tractament de les infeccions de pròtesis articulars en un temps pot ser (en general) tan efectiva com la revisió en dos temps. • La infecció protèsica estreptocòccica manejada amb DAIR va mostrar un pitjor pronòstic del descrit prèviament a la literatura. Un bon maneig de les guies IDSA, el recanvi dels components mòbils i la potencial eficàcia del tractament combinat amb rifampicina podrien millorar aquest modest pronòstic. • L’estandardització d’un mètode UHLPC-MS/MS per la determinació de betalactàmics permet la monitorització de nivells en pacients tractats amb perfusió contínua. • Mitjançant la comparació amb els resultats UHLPC-MS/MS s’ha pogut validar una equació simple per una estimació individualitzada de la dosi òptima de betalactàmics en perfusió continua i de nivells en plasma . • L’ús clínic de betalactàmics en perfusió continua és segur y eficaç. • Afegir colistina als betalactàmics en el tractament de les infeccions osteoarticulars produïdes per BGN multiresistents mostra millors resultats que el tractament en monoteràpia amb betalactàmic. • En el model in vitro per la formació de biofilm, també hem objectivat el benefici de la teràpia combinada amb colistina.
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D'Urso, Paul Steven. "Stereolithographic biomodelling in surgery /". [St. Lucia, Qld.], 1998. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17881.pdf.
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Midha, Prem Anand. "Long-term patency of a polymer vein valve". Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29721.
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Thesis (M. S.)--Bioengineering, Georgia Institute of Technology, 2010.Committee Chair: Ku, David; Committee Member: Gleason, Rudolph; Committee Member: Milner, Ross. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Yuen, Chi-keung. "Opportunities and limitations of "resorbable" metallic implant risk assessment, biocorrosion and biocompatibility, and new directions with relevance to tissue engineering and injury management techniques /". Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B41633659.
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