abstract: This thesis focuses on the theoretical work done to determine thermodynamic properties of a chalcopyrite thin-film material for use as a photovoltaic material in a tandem device. The material of main focus here is ZnGeAs2, which was chosen for the relative abundance of constituents, favorable photovoltaic properties, and good lattice matching with ZnSnP2, the other component in this tandem device. This work is divided into two main chapters, which will cover: calculations and method to determine the formation energy and abundance of native point defects, and a model to calculate the vapor pressure over a ternary material from first-principles. The purpose of this work is to guide experimental work being done in tandem to synthesize ZnGeAs2 in thin-film form with high enough quality such that it can be used as a photovoltaic. Since properties of photovoltaic depend greatly on defect concentrations and film quality, a theoretical understanding of how laboratory conditions affect these properties is very valuable. The work done here is from first-principles and utilizes density functional theory using the local density approximation. Results from the native point defect study show that the zinc vacancy (VZn) and the germanium antisite (GeZn) are the more prominent defects; which most likely produce non-stoichiometric films. The vapor pressure model for a ternary system is validated using known vapor pressure for monatomic and binary test systems. With a valid ternary system vapor pressure model, results show there is a kinetic barrier to decomposition for ZnGeAs2. / Dissertation/Thesis / M.S. Materials Science and Engineering 2011

Ce travail a pour objectif d'étudier la tenue en fatigue de l'alliage de fonderie A356-T6 sous chargement multiaxial. Des essais en fatigue à 106 cycles ont été effectués pour deux rapports de chargements différents à Rσ = 0 et Rσ = -1. La première partie expérimentale est menée sur des éprouvettes issues d'une coulée en ‘V’ avec des défauts naturels de fonderie et des défauts artificiels avec une variation de la microstructure. Suite aux résultats expérimentaux, nous avons montré que la taille des défauts ainsi que la microstructure caractérisée par la SDAS, sont les principaux paramètres qui influencent la limite de fatigue de cet alliage. Par comparaison entre les résultats obtenus à Rσ = 0 et Rσ = -1, il s'avère que la contrainte moyenne joue un rôle primordial sur la sensibilité du matériau à la taille du défaut et à la SDAS. Dans la suite, des modifications ont été menées sur le critère de DSG qui consistent à introduire l’effet de la SDAS au niveau du critère. L’application de ce critère modifié dans un diagramme de Kitagawa pour les différents cas de chargement a montré que l’abattement de la limite de fatigue en fonction de la taille de défaut et de la SDAS est bien décrit. Dans la dernière partie un outil numérique a été développé permettant de simuler la limite de fatigue en partant du procédé de fonderie. Cette démarche est sous forme d’une chaîne de calcul numérique qui permet de simuler la taille de défaut et de la SDAS à partir du procédé de fonderie. Suite à cette simulation, le modèle est capable de prévoir la limite de fatigue en utilisant le critère de DSG modifié. La combinaison entre la loi de Weibull et le critère de DSG permet à la suite de la chaîne de simulation de prévoir ainsi la probabilité de rupture à chaque point de la structure. Nous avons proposé dans cette partie un moule qui permet d’élaborer des éprouvettes avec deux microstructures différentes. Dans cette étude, une deuxième campagne d’essais a été réalisée sur ces éprouvettes afin de valider la simulation numérique sur le moule proposé. Le modèle numérique prévoit raisonnablement bien les résultats expérimentaux obtenus. / This study aims to investigate the fatigue behaviour of A356-T6 aluminum alloy. Experimental fatigue tests at 106 cycles have been performed for two loading ratios: Rσ = 0 and Rσ = -1. The first experimental investigation was conducted on specimens from a ‘V’ wedge casting with natural and artificial defects which provides a variation of the microstructure. Following the experimental results, we have shown that defects characterized by their size and the microstructure characterized by SDAS, are the main parameters that control the fatigue limit. By comparing the results obtained for both loading ratios, it appears that the mean stress has an effect on the sensitivity to the defect size effect and microstructure.The DSG criterion was modified to introduce the effect of SDAS. This improved DSG criterion has been employed to predict the Kitagawa diagram for multiaxial loading for different loading cases. The simulation of the modified DSG criterion showed that the reduction of the fatigue limit with the defect size and SDAS is well described. In the last part a numerical model was developed to perform a simulation of the fatigue limit starting from the casting process. Using this numerical model, we simulated the defect size and SDAS depending on the solidification time, eventually the fatigue limit issimulated using the improved DSG criterion. With combining between Weibull law and modified DSG,we predict the probability of failure at each point of the structure. We proposed in this part a mold which let to obtain samples with two different microstructures. In this study, a second fatigue tests was carried out on these samples to validate the numerical simulation on the proposed mold. It turns out that the numerical model provides reasonably well the obtained experimental results.

Esta dissertação apresenta a modelagem e o monitoramento de características de qualidade do tipo taxa, que apresentam valores restritos ao intervalo [0,∞). A motivação inicial é que a característica de qualidade do tipo taxa pode ser modelada pela distribuição Poisson e, geralmente, a modelagem e o monitoramento não utilizam tal distribuição. Os objetivos desta dissertação são: (i) Propor uma nova carta de controle (CC), Carta Poisson, para monitorar características de qualidade do tipo taxa, com adaptação no cálculo dos limites de controle utilizando a distribuição Poisson; (ii) Propor uma CC baseada em modelo de regressão utilizando a distribuição de Poisson para monitorar características de qualidade do tipo taxa em função das variáveis de controle do processo e (iii) Propor índices de capacidade MRPOISSON Cp e MRPOISSON Cpk para avaliar processos monitorados por CCs baseadas em modelos de regressão utilizando a distribuição de Poisson. As cartas de controle e os índices de capacidade propostos foram avaliados aplicando exemplos retirados da literatura. As cartas de controle foram comparadas através do número médio de amostras (NMA) via simulação de Monte Carlo. Concluiu-se que as cartas de controle propostas são adequadas para a modelagem e o monitoramento de características de qualidade do tipo taxa pois detectaram mais rapidamente todas as alterações induzidas, apresentando melhor desempenho em comparação com outras cartas similares encontradas na literatura. / This paper presents the modeling and monitoring of quality features like rate, which have values restricted to the interval [0, ∞). The initial motivation is that the quality characteristic of the type rate can be modeled by the Poisson distribution, and generally, modeling and monitoring do not use such a distribution. The objectives of this dissertation are: (i) to propose a new control chart (CC), Poisson Charter, to monitor quality characteristics of the type rate, adapted to calculate the control limits using a Poisson distribution, (ii) propose a CC based on regression model using the Poisson distribution to monitor quality characteristics like rate as a function of the control variables of the process and (iii) Propose capability indices MRPOISSON Cp and MRPOISSON Cpk to evaluate processes and monitored by CCs based on regression models using the distribution of Poisson. The control charts and capability indices were estimated by applying the proposed examples from the literature. The control charts were compared using the average number of samples (NMA) via Monte Carlo simulation. It was concluded that the proposed control charts are suitable for modeling and monitoring of quality characteristics of the type detected faster rate because all the changes induced, showing better performance in comparison with other similar letters found in the literature.

Deux innovations en matière de procédés technologiques des semi-conducteurs sont des alternatives à la technologie traditionnelle des transistors MOS (« Metal-Oxide-Semiconductor ») « Bulk » planaires : d’une part le silicium totalement déserté sur isolant (FDSOI – « Fully Depleted Silicon on Insulator ») et d’autre part les transistors à effet de champ à aileron (FinFET – « Fin Field Effect Transistor »). En effet, alors que la technologie « Bulk » arrive à ses limites de miniaturisation des composants et systèmes, notamment du fait de l’effet de canal court, ces deux technologies présentent des propriétés prometteuses pour poursuivre cette réduction des dimensions, grâce à un meilleur contrôle électrostatique de la grille sur le canal du transistor. La technologie FDSOI est, comme l’historique « Bulk », une technologie MOS planaire, ce qui la place naturellement davantage dans la continuité technologique que les ailerons verticaux des transistors FinFETs. La compétition entre ces deux technologies est rude et de nombreuses études publiées dans la littérature comparent ces technologies en termes de performance en vitesse de fonctionnement, de consommation, de coût, etc. Néanmoins, aucune étude ne s’était encore penchée sur leurs propriétés respectives en termes de testabilité ; pourtant l’impact de défauts sur les circuits réalisés en technologies FDSOI et FinFET est susceptible d’être significativement de celui induit par des défauts similaires sur des circuits planaires MOS.Le travail présenté dans cette thèse se concentre sur la conception de circuits d’étude similaires dans chacune des trois technologies et l’analyse comparative de leur comportement électrique sous l’effet d’un même défaut. Les défauts considérés dans notre étude sont les courts-circuits résistifs inter-portes, court-circuit résistif à la masse (GND), court-circuit résistif à l’alimentation (VDD), et circuits ouverts résistifs. La détectabilité des défauts est évaluée pour le test logique statique et le test dynamique en « délai ». Des simulations HSPICE et Cadence SPECTRE ont été effectuées en faisant varier la valeur de la résistance du défaut et le concept de résistance critique est utilisé afin de comparer la plage de détectabilité du défaut dans les différentes technologies. Les conditions optimales de polarisation du substrat (« body-biasing »), de tension d’alimentation et de température en vue d’obtenir la meilleure couverture de défauts possible sont déterminées pour chaque type de défaut. Un modèle analytique, basé sur la résistance équivalente des réseaux de transistors N et P actifs (« ON-resistance »), est proposé pour les courts-circuits résistifs, et permet d’évaluer la valeur de la résistance critique sans effectuer de simulation de fautes. Les propriétés en termes de testabilité sont également établies en tenant compte des variations de procédés, par des simulations Monte-Carlo réalisées aussi bien pour les dispositifs à tension de seuil nominale (« Regular-VT devices » : FDSOI-RVT et Bulk-LR) que pour les dispositifs à tension de seuil basse (« Low-VT devices » : FDSOI-LVT et Bulk-LL) disponibles pour les technologies 28 nm Bulk et FDSOI. / Fully Depleted Silicon on Insulator (FDSOI) and Fin Field Effect Transistor (FinFET) are new innovations in silicon process technologies that are likely alternatives to traditional planar Bulk transistors due to their respective promising ways of tackling the scalability issues with better short channel characteristics. Both these technologies are aiming in particular at regaining a better electrostatic control by the gate over the channel of the transistor. FDSOI is a planar MOS technology and as a result it is much more in continuity with planar Bulk as compared to the vertical FinFET transistors. The competition between these two technologies is fierce and many studies have been reported in the literature to compare these technologies in terms of speed performance, power consumption, cost, etc. However, these studies have not yet focused on their testability properties while the impact of defects on circuits implemented in FDSOI and FinFET technologies might be significantly different from the impact of similar defects in planar MOS circuit.The work of this thesis is focused on implementing similar design in each technology and comparing the electrical behavior of the circuit with the same defect. The defects that are considered for our investigation are inter-gate resistive bridging, resistive short to ground terminal (GND), resistive short to power supply (VDD) and resistive open defects. Defect detectability is evaluated in the context of either logic or delay based test. HSPICE and Cadence SPECTRE simulations are performed varying the value of the defect resistance and the concept of critical resistance is used to compare the defect detectability range in different technologies. The optimal body-biasing, supply voltage and temperature settings to achieve the maximum defect coverage are determined for these defect types. An analytical analysis is proposed for short defects based on the ON-resistance of P and N networks, which permits to evaluate the value of the critical resistance without performing fault simulations. Testability properties are also established under the presence of process variations based on Monte-Carlo simulations for both Regular-VT devices (FDSOI-RVT and Bulk-LR) and Low-VT devices (FDSOI-LVT and Bulk-LL) available for 28nm Bulk and FDSOI technologies.

Printed electronics is a combination of electronics and printing technologies commonly used in the publication industry such as screen, inkjet, and roll to roll printing. The measurements of conductive film particularly the conductive paste is the main objective of this thesis. The conductive paste consists of conductive filler, adhesive and solvent. Each component affects the electrical, and mechanical properties of the finished conductive film product. The measurements of conductive film have three field of study. The first category is the lifetime performance measurement of conductive film using environmental testing. A screen printed carbon, silver and a developmental paste were categorised to environmental testing and third harmonic measurement. The second category is the measurement AC Impedance and DC resistance of conductive ink during cure. During the curing of the pastes, the AC impedance and DC resistance were monitored. A LabVIEW program was developed to control the AC impedance analyser, DC resistance ohmmeter, and convection oven. Samples were measured whilst curing at different curing temperatures and for a range of particle loadings. Particle loading is the percentage of conductive filler against the rest of the chemical in the conductive paste. The last category was defect detection using the combination of electromechanical testing, a Scanning Electron Microscope (SEM) and an Infrared (IR) imaging technique. Printed carbon and silver were mechanically aged by bending the printed structure up to 100 k times. The results from the lifetime performance measurements on carbon, silver and the developmental paste showed the polymer resin behaviour in high humidity and high temperature environments. The increased oxidation rate due to the elevated temperatures affected the conductive particle of certain pastes. The third harmonic testing technique was able to detect failures on conductive film in the form of width reduction. The AC impedance measurement technique could indicate the final resistivity value. The AC impedance measurement was affected by the test frequency used while the ink is in liquid state. Correct test frequency setting will have less noise and less impedance value, vital in predicting the final cured resistance of the printed paste. The curing temperature affects the final cured resistance value while the particle loading affects the rate of curing of conductive film. The electrical measurement on mechanically aged samples showed that the carbon prints have its resistance readings below its initial value while the silver prints resistance increased. SEM images shows that the carbon print indicates no visual damage on the surface after 100 k bent cycle, while physical defects were observed in silver prints. The infrared measurements on carbon prints showed an increase in temperature while developments of heat patches were observed on silver prints. Difference in emissivity values of materials used provided the contrast effect which plays an important role in detecting defect using infrared imaging technique because. Third harmonic application to the printed electronics is new to this field. Normally, testing is done using environmental testing to determine the lifetime performance of the conductive film. This is effective however requires a lot of time and effort to produce a result. AC Impedance is used widely and the application can be seen on cured printed electronics. The application and measurement of AC impedance during cure and DC resistance measurement has indicated initial resistivity values. The measurement has further the effect of using AC impedance on different curing temperature and particle loading. The phase measurement as well has brought insight of degree of curing. The application of infra-red imaging technique to the mechanically aged device has produced a result that DC resistance and SEM imaging failed to detect. Normally DC resistance measurement was used as quality assessment tool but test shows on mechanically aged product failed to detect increase in resistance due to mechanical aging techqnique.

Made available in DSpace on 2014-08-06T17:29:38Z (GMT). No. of bitstreams: 2 Aline Costa.pdf: 2324687 bytes, checksum: 04115292021785e54c4bf64f9a7bc8fd (MD5) license.txt: 1914 bytes, checksum: 7d48279ffeed55da8dfe2f8e81f3b81f (MD5) Previous issue date: 2010 / Fundação Oswaldo Cruz. Instituto Fernandes Figueira. Departamento de Ensino. Programa de Pós-Graduação em Saúde da Criança e da Mulher. Rio de Janeiro, RJ, Brasil. / O objetivo desse trabalho foi discutir o aconselhamento genético (AG) como prática clínica, focalizando a anencefalia que é um defeito de fechamento de tubo neural (DFTN) aberto, acometendo 1:1000 nascimentos, e sua associação com outras malformações maiores. Para tanto foi empreendido o levantamento de laudos de necropsias realizadas no Departamento de Anatomia Patológica do Instituto Fernandes Figueira/FIOCRUZ, entre 2000 e 2008, e dos respectivos prontuários das gestantes dos quais constava o resultado dos achados da ultrasonografia gestacional (USG). A análise dos dados foi feita utilizando o Epi-Info/ANOVA. Os resultados apontaram: a) 74 necropsias realizadas no período, das quais 56,7% indicaram anencefalia isola, 14,9% mostraram outro DFTN e 28,4% associada com outras malformações; b) as malformações mais frequentemente associadas com a anencefalia foram: raquisquise, fenda labial ou e palatina, onfalocele, hérnia diafragmática e baço acessório; c) o diagnóstico da USG mostrou anencefalia isolada em 87,4% dos casos; associada com outro DFNT em 2,8% e múltiplas malformações em 9,8%, das quais as mais frequentes foram: raquisquise, onfalocele, defeito de parede tóraco-abdominal com ectopia cordis; d) a maioria das gestantes tinha segundo grau completo, eram primigestas, com história familiar de DFTN em 9,4% dos casos, sendo que em 6,7% deles houve exposição a teratogênos e 20% tiveram complicações gestacionais, sendo a polidraminia a mais frequente; e) em nenhum dos casos achou-se referência ao uso de ácido fólico pré e periconcepcional; f) após a confirmação diagnóstica, 49,3% gestantes decidiram pela interrupção judicial da gravidez e 50,7% evoluiram para o parto (36% natimortos e 64% nativivos) e, por fim, g) 42% das gestantes realizou consulta no ambulatório de AG pósnatal, depois do desfecho da gestação. Concluiu-se que diante do diagnóstico de anomalia tão grave e incompatível com a vida extra-uterina, as demais malformações perdem significado no momento da USG, o tem repercussões para o direcionamento do AG relacionado às opções reprodutivas futuras. Por outro lado reiterou-se a importância da suplementação oral de ácido fólico no período pré e periconcepcional como medida de prevenção primária e de promoção da saúde. / The aim of this investigation was to discuss genetic counseling as a clinical practice, focusing on anencephaly, which is an open neural tube defect that affects 1:1000 births, and its relation to other major malformations. For this purpose, we undertook a survey of autopsy reports, performed at the pathology department of Instituto Fernandes Figueira/FIOCRUZ between 2000-2008, and medical charts of the related mothers, where data on the obstetric ultrasound was registered. Data analysis was performed with Epi-Info/ANOVA. The results point to: a) 74 autopsies were executed during this period; 56,7% revealed isolated anencephaly, 14,9% were associated to other neural tube defects, and 28,4% were associated to other malformations; b) malformations most frequently associated were: rachischisis, cleft lip and/or palate, omphalocele, diaphragmatic hernia, and accessory spleen; c) obstetric ultrasound showed isolated anencephaly in 87,4% of the cases; association to other neural tube defects in 2,8%, and multiple malformations in 9,8%, the most frequent being rachischisis, omphalocele, thoraco-abdominal wall defect, and ectopia cordis; d) the majority of pregnant woman had completed high school and were pregnant for the first time; family history for neural tube defect was positive in 9,4% of the cases, of which 6,7% were associated to teratogen exposure, and 20% presented with pregnancy complications, mostly polyhydramnios; e) we found no record of folic acid use before or peri-conception; f) after diagnosis, 49,3% of pregnant women decided for pregnancy interruption, and 50,3% delivered their babies (36% stillbirths, 64% newborns), and g) genetic counseling was given to 42% of women. We come to the conclusion that facing such a serious, and deadly anomaly, all other malformations loose their value, what reflects upon genetic counseling and reproductive choices. Besides, we emphasize the need of folic acid use before and peri-conception as a primary prevention and health promotion measure.

This thesis describes work on the theoretical modelling and experimental measurement of the complex permittivity of dielectrics. The main focus of research has been into the characterisation of permittivity of planar and layered samples within the millimetre wave band. The measurement method is based on the free-space measurement of the transmission and reflection coefficients of samples. A novel analytical method of determining the transmission and reflection coefficients as functions of frequency arising from a generalised structure of planar dielectric layers is also described and validated. The analytical method is based on signal flow techniques. The measurement and analytical techniques have been applied in two main areas: firstly, the acquisition of new data on human skin in the band 57 to 100GHz and secondly, the detection and location of defects in composite materials for which a band of 90 to 100GHz was used. Measurements have been made on the complex permittivity of a single sample of excised human skin fixed in formaldehyde. The experimental results have been corrected to account for the fixing process in formaldehyde and are projected to body temperature. This data is, to the best of the author’s knowledge, the first of its kind to be published. Predicted skin permittivity based on various relaxation models varies widely and only partially fits the measured data. The experimental results have been used to determine the parameters of a Cole-Cole function which gives the best fit to the measured data. The measured skin data has also been used to calculate power deposition in skin exposed to millimetre wave radiation. This work concludes that a skin surface temperature rise of only 0.20C results from a thirty second exposure to signals of 100W/m2. Experimental work with fibreglass composite samples has shown that defects such as delaminations, voids, matrix cracks and improper cure result in resolvable differences in the dielectric properties of the samples at 90 – 100GHz. The measurement technique is particularly sensitive to the detection of cracks and its spatial resolution is 20mm or better. Whilst confirming the general conclusions of previously published work, the specific findings of this study are novel.

abstract: Integrated oxide/semiconductor heterostructures have attracted intense interest for device applications which require sharp interfaces and controlled defects. The research of this dissertation has focused on the characterization of perovskite oxide/oxide and oxide/semiconductor heterostructures, and the analysis of interfaces and defect structures, using scanning transmission electrom microscopy (STEM) and related techniques. The SrTiO3/Si system was initially studied to develop a basic understanding of the integration of perovskite oxides with semiconductors, and successful integration with abrupt interfaces was demonstrated. Defect analysis showed no misfit dislocations but only anti-phase boundaries (APBs) in the SrTiO3 (STO) films. Similar defects were later observed in other perovskite oxide heterostructures. Ferroelectric BaTiO3 (BTO) thin films deposited directly onto STO substrates, or STO buffer layers with Ge substrates, were grown by molecular beam epitaxy (MBE) in order to control the polarization orientation for field-effect transistors (FETs). STEM imaging and elemental mapping by electron energy-loss spectroscopy (EELS) showed structurally and chemically abrupt interfaces, and the BTO films retained the c-axis-oriented tetragonal structure for both BTO/STO and BTO/STO/Ge heterostructures. The polarization displacement in the BTO films of TiN/BTO/STO heterostructures was investigated. The Ti4+ atomic column displacements and lattice parameters were measured directly using HAADF images. A polarization gradient, which switched from upwards to downwards, was observed in the BTO thin film, and evidence was found for positively-charged oxygen vacancies. Heterostructures grown on Ge substrates by atomic layer deposition (ALD) were characterized and compared with MBE-grown samples. A two-step process was needed to overcome interlayer reaction at the beginning of ALD growth. A-site-rich oxide films with thicknesses of at least 2-nm had to be deposited and then crystallized before initiating deposition of the following perovskite oxide layer in order to suppress the formation of amorphous oxide layers on the Ge surface. BTO/STO/Ge, BTO/Ge, SrHfTiO3/Ge and SrZrO3/Ge thin films with excellent crystallinity were grown using this process. Metal-insulator-metal (MIM) heterostructures were fabricated as ferroelectric capacitors and then electrically stressed to the point of breakdown to correlate structural changes with electrical and physical properties. BaTiO3 on Nb:STO was patterned with different top metal electrodes by focused-ion-beam milling, Au/Ni liftoff, and an isolation-defined approach. / Dissertation/Thesis / Doctoral Dissertation Materials Science and Engineering 2018

Made available in DSpace on 2014-06-11T19:23:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-24Bitstream added on 2014-06-13T20:48:19Z : No. of bitstreams: 1 burger_cp_me_jabo.pdf: 769968 bytes, checksum: 7766d90823dbf5c423709325e1af199c (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O tratamento de não união e união retardada é um desafio constante na rotina do ortopedista veterinário. A dificuldade de se conseguir repouso adequado dos pacientes submetidos à osteossíntese, frequentemente, resulta em consolidações mal sucedidas. Com o objetivo de se avaliar o comportamento do cimento de aluminato de cálcio, foram induzidos defeitos ósseos de 3,57mm de diâmetro nos fêmures de 12 coelhos, sendo os do lado direito preenchidos com o referido biomaterial e os do esquerdo permaneceram vazios. Aos 15, 30 e 60 dias de pós-operatório, realizaram-se avaliações clínico-cirúrgicas, radiográficas e histológicas, a fim de se observar o potencial osteoindutor e osteocondutor do biomaterial no defeito ósseo, e se houve osteointegração. Os resultados evidenciaram que o cimento aluminoso, nesta formulação, não possui esses potenciais e nem poder de osteointegração, possivelmente por possuir porosidade reduzida / The treatment of non union and delayed union is a constant challenge for veterinary orthopedists. The difficulty in achieving adequate rest for patients which have undergone osteosynthesis results in unsuccessful bone consolidations. With the aim of evaluating the behavior of a calcium aluminate cement, bone defects of 3,57 mm of diameter were induced in femurs of 12 rabbits. The defects on the right side were filled with the biomaterial and the ones on the left side remained unfilled. The evaluation periods occurred at 15, 30 and 60 days after surgery. Clinical, surgical, radiographic and histological evaluations were performed in order to observe the osteoinductive and osteocondoctive potential of the biomaterial on the bone defects, as well to verify if there was osteointegration. The results showed that the aluminate cement does not have these potencial and nor cause osteointegration in the formulation used in this study

Made available in DSpace on 2014-06-11T19:23:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2005Bitstream added on 2014-06-13T19:50:51Z : No. of bitstreams: 1 pereirajunior_ocm_me_botfmvz.pdf: 3167867 bytes, checksum: 1d9dcf46127172271d23518809985b22 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Objetivou-se avaliar, por meio de exames radiográficos e histológicos, a função da resina de poliuretana derivada do óleo de mamona (Ricinus communis), na forma de grânulos, no tratamento de defeito ósseo segmentar induzido no rádio de coelhos, tendo como padrão comparativo o enxerto ósseo esponjoso autólogo. Foram utilizados 20 coelhos da raça Norfolk, fêmeas, com idade entre 12 e 14 meses e peso entre 4 e 5kg. Uma falha óssea segmentar de 1,0 cm de comprimento foi induzida na diáfise de ambos os rádios pela excisão de fragmento osteoperiosteal. No rádio esquerdo o defeito foi tratado com a resina de poliuretana e no direito com auto-enxerto esponjoso colhido do úmero proximal esquerdo. Para realização dos exames histológicos foram eutanaziados cinco animais aos 15 dias, 30 dias, 60 dias e 120 dias de pós-operatório. A regeneração óssea foi maior no defeito tratado com auto-enxerto esponjoso em todos os períodos de observação, sendo que, aos 120 dias de pós-operatório, estes estavam totalmente reconstituídos. Pela avaliação histológica o polímero de mamona atuou como preenchedor de espaço, minimizando a produção de tecido fibroso no local, além de não apresentar sinais de reabsorção em nenhum dos momentos de avaliação. Foi possível concluir que o polímero de mamona na forma de grânulos é biocompatível e osteointegrável, porém não apresenta a mesma capacidade de regeneração óssea do auto-enxerto esponjoso. / The aim of the present study was to compare, by radiographic and histological analyses, the castor oil plant polyurethane in granules presentation, applied to a segmental bone defect, created in both radial diaphyses, to the cancellous bone autograft, in order to evaluate an alternative to bone defect healing. Norfolk adult female rabbits, with approximately 13 months of age and a mean body weight of 4.5kg were used. Thus, a one-cm segmental defect was created in both radial diaphyses. The defect in the left radius was filled with the castor oil plant polyurethane, and the right one, filled with cancellous bone autograft, collected from the left proximal humerus. The rabbits were euthanased at 15, 30, 60 and 120 days post-surgery (5 animals/period), in order to proceed the histological analysis. New bone formation was increased and accelerated in the defect treated with cancellous bone autograft along all periods of observation. In the last moment (120 days), the defects were totally reconstituted and remodeled. The polyurethane acted as a space filler, minimizing the local production of fibrous tissue. No granules degradation or reabsorb were detected, as well as any inflammatory reaction. Thus, it was possible to conclude that the castor oil plant polyurethane, in granules presentation, was biocompatible and osteointegrated, but did not show the same bone regeneration capacity of the cancellous bone autograft.