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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Avaliação das propriedades mecânicas de um silicone de cura acética com adição de silicato de magnésio / Evaluation of the mechanical properties of the cured acetic silicone added with magnesium silicate

Orellana, Ronald Vargas 19 October 2007 (has links)
Os silicones requerem várias caraterísticas e requisitos para seu uso na confecção de próteses faciais, principalmente, referente a textura da pele; para alcançar essa meta devem ser adicionados outros materiais. O objetivo deste trabalho foi avaliar as propriedades mecânicas de um silicone nacional RTV. de cura acética, disponível no mercado, adicionando silicato de magnésio (talco). O material foi estudado em seu estado original e com acréscimo de 10% e 20% de silicato de magnésio. Foi submetido a testes de alongamento de ruptura, resistência à tração ou tensão de ruptura e de resistência ao rasgamento. Após a avaliação individual dos corpos de prova, obteve-se uma média total de cada grupo e submeteu-se a estudo comparativo frente aos resultados obtidos por meio de análise de variância (ANOVA) e teste de Tukey. O silicone em estado original mostrou-se mais resistente ao alongamento. O silicone com adição de 10 % de silicato de magnésio modificou suas propriedades mecânicas e obteve maior resistencia à tração. O silicone com adição de 20 % de silicato magnésio obteve maior resistência ao rasgamento. O silicone em que foi adicionado 10 % de silicato de magnésio de maneira geral obteve os valores mais significativos nas três propriedades testadas, o que indica que adicionando mais de 10 % diminui as propriedades mecânicas gradualmente, tornando-se inversamente proporcionais. / The silicones request many characteristics and requirements for the use in the making of facial prostheses. To reach that objective other materials should be added. The aim of this work was to evaluate the mechanical properties of a national acetic cure silicone RTV, available in the market, adding silicate of magnesium (talc). The material was studied in your natural state and with increment of 10% and 20% of silicate of magnesium. It was submitted to tests of elongation and break, tensile strength and tear strength. After the individual evaluation of the specimens, it was obtained measured total of the each group and submitted to study comparative front to the results obtained through variance analysis (ANOVA) and Tukey test. The silicone in been original it showed to be more resistant to the elongation. The silicone with addition of 10% of silicate of magnesium modified your mechanical properties and obtained larger tear resistance. The silicone with addition of 20% of silicate magnesium obtained larger resistance to the tear strength. The silicone in witch it added 10% of silicate of magnesium in general obtained the more significant values in the three tested properties; that means that the increment of more than 10% lesses the properties gradually, becoming inversely proportional.
72

Contribution à l’évaluation du comportement des revêtements silicones acrylates photoréticulés en fin de vie. Influence du système de photoamorçage sur la dégradation bio-physico-chimique / Contribution to the evaluation of the behavior of photocured silicone acrylate coatings at their end of life. Influence of the photoinitiator system on bio-physico-chemical degradation

Ouali, Salma 13 April 2017 (has links)
Les silicones acrylates photoréticulés sont largement utilisés dans les revêtements de divers matériaux. Leur production nécessite l’utilisation d’un photoamorceur considéré comme potentiellement reprotoxique, ce qui impose aux producteurs de revêtements silicones d’imaginer des formulations alternatives. L’augmentation de la consommation de ce type de revêtements amène à s’interroger sur leur devenir au cours et en fin de vie dans les filières de traitement des déchets et sur l’influence du changement de photoamorceur sur le comportement environnemental des revêtements. Ce domaine de recherche demande la mise en place d’une méthodologie spécifique, alliant des expériences de dégradation physico-chimiques et biologiques. Deux types de revêtements photoréticulés par deux photoamorceurs différents : le Darocur 1173 et Darocur 1173 modifié (nouveau photoamorceur) font l’objet de cette étude. L’exposition des revêtements silicones aux UV a montré que ces composés sont facilement dégradables et sensibles au photovieillissement. L’enduction silicone augmente, elle, la photosensibilité des films revêtus. Dans un contexte de fin de vie, les essais réalisés sur la matrice silicone ont permis de mettre en évidence une légère hydrolyse chimique des chaines siloxanes, non biodégradables aussi bien en aérobiose qu’en anaérobiose mais dont la présence n’inhibe pas l’activité microbienne. Les photoamorceurs testés présentent des comportements totalement différents face à la lixiviation et à la dégradation biologique: ainsi, le Darocur 1173 est très mobile en phase aqueuse, facilement assimilable par les microorganismes comme source primaire de carbone en conditions aérobies contrairement au Darocur 1173 modifié. Qu’il y ait eu biodégradation ou non, la structure de la communauté microbienne est influencée différemment suivant le photoamorceur utilisé. L’utilisation du Darocur 1173 modifié permet de diminuer le risque de migration et sa toxicité potentielle dans les revêtements silicones. La démarche mise en œuvre apporte de nombreuses informations quant aux impacts environnementaux et pourra servir d’exemple pour l’étude d’autres déchets silicones. / Photocrosslinked silicones acrylates are widely used in coatings of various materials. Their production requires the use of photoinitiator considered as potentially reprotoxic, which requires producers of silicone coatings to devise alternative formulations. Consumption increase of this type of coatings raises questions about their fate during and at their end-of-life in waste treatment channels and the influence of photoinitiator change on the environmental behavior of the coatings. This research area needs the use of a specific methodology, combining physico-chemical and biological degradation experiments. Two types of coatings photocrosslinked by two different photoinitiators: Darocur 1173 and modified Darocur 1173 (new photoinitiator) are the subject of this study. UV exposure of silicone coatings showed that these materials are easily degradable and sensitive to photoageing. The silicone coating increases the photosensitivity of coated films. At the end-of-life stage, performed experiments on silicone coatings revealed a slight chemical hydrolysis of the non-biodegradable siloxane chains, both under aerobic and anaerobic conditions. However, these materials does not inhibit the microbial activity. The tested photoinitiators have totally different behavior regarding the leaching and biological degradation: Darocur 1173 is very mobile in aqueous phase, easily assimilated by microorganisms as a primary sole of carbon under aerobic conditions in contrast to modified Darocur 1173. Whether there has been biodegradation or not, the structure of microbial communities is influenced differently depending on the used photoinitiator. Modified Darocur 1173 reduces the risk of migration and its potential toxicity in silicone coatings. The implemented approach brings a lot of information about the environmental impacts and can serve as an example for the study of other silicone waste.
73

Avaliação das propriedades físicas de dois materiais flexíveis de produção nacional para uso em prótese facial / Evaluation of the physical properties of two flexível materials domestic produced, to create facial prosthesis

Tinajero, Luis Pablo Herrera 19 January 2011 (has links)
Para confeccionar próteses faciais e reabilitar aqueles pacientes com perdas anatômicas, são empregados diversos materiais, destacando-se entre estes os flexíveis,devido á semelhança estética que apresentam com a pele humana. O padrão de qualidade dos materiais é liderado por produtos estrangeiros, tornando difícil a obtenção e, por tanto, a aplicação dos mesmos em território nacional. Devido à necessidade de se ter materiais nacionais com qualidade semelhante aos importados, este trabalho mensurou dois materiais, a resina resiliente CLASSIFLEX e o silicone médico ORTHO PAUER, ambos de produção nacional, seguindo as normas da ASTM (American Standard for testing materiais). Foram testadas dureza Shore A, resistência ao rasgamento, resistência a tração e alongamento de ruptura. Os valores obtidos foram analisados estatisticamente e comparados entre sim. Os valores de resistência a tração, resistência ao rasgamento e dureza Shore A, dos materiais testados foram baixos quando comparados com os valores encontrados em outras pesquisas .Os valores de Alongamento de ruptura se encontram dentro dos valores aceitáveis para matérias de uso em reabilitação buco maxilo facial. / To fabricate and create facial prosthesis for those patients with anatomical loss, maxillo facial protesiologist use differet materials. Flexible materials has being used mostly because of their aesthetic similarity with the skin. The standard for quality in prostethic materilas is led by foreign products, making it difficult to obtain and apply these materials in national territory. Due to the necessity of giving new and better materilas the CLASSIFLEX resilient resin and the ORTHO PAUER medical silicone, both of domestic production, were selected to test the fisical properties of: Shore A hardness, elongation, tensile strength and tear strenght. The specimens were made following the parameters indicated by the ASTM and each test was performed. The values obtained were analyzed statistically and compared. The results obtained may conclude that the physical properties of tensile srtrenght, tear strenght and Shore A hardness were low when compared with the results observed in other similar studies. The values obtained from the elongation test shows similarity of other values obtained by past studies.
74

Efeito de diferentes fontes de sangue sobre a performance reprodutiva de Aedes aegypti L., 1762 (D?ptera: Culicidae) alimentados atrav?s de membrana de silicone / Effect of different blood sources on the reproductive performance of Aedes aegypti L., 1762 (Diptera: Culicidae) fed through silicone membrane device

PINA, Isabelle Garcia 30 September 1997 (has links)
Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-02-14T17:34:23Z No. of bitstreams: 1 1997 - Isabelle Garcia Pina.pdf: 529649 bytes, checksum: d067fa62978c5955301ef929db0ee4f8 (MD5) / Made available in DSpace on 2017-02-14T17:34:23Z (GMT). No. of bitstreams: 1 1997 - Isabelle Garcia Pina.pdf: 529649 bytes, checksum: d067fa62978c5955301ef929db0ee4f8 (MD5) Previous issue date: 1997-09-30 / CNPq / This experimental work with Aedes aegypti L. (1762) was conducted in order to compare the effect of differents blood sources on feeding and egg production of mosquitoes? females. The blood-feeding device consisted of a plastic cage ? used for holding females during blood feeding ? with two lateral windows recovered with thin cloth to allow air exchange during feeding. In the top of the cage, there was an opening where the food?s container, recovered with silicone membrane, was attached. A larger vial filled with water at the initial temperature of 50 ?C was used over the apparatus to keep the food source warm (37,5 ? 0,5%). In each trial, three different treatments were tested: whole blood collected from mouse, bovine and human. To prevent coagulation, a 3,9% solution of sodium citrate was added to the blood. The control group was allowed to feed directly on human volunteers. The experiment was conducted in a climatic chamber, with temperature and humidity controlled at 28?0,5 ?C and 80?5%, respective values and the photoperiod of 12 hours of light and 12 hours of darkness. In each tested group, 30 females and 10 males mosquitoes were used. The females were allowed to feed during a period of 20-30 minutes and after that only the engorged females were transferred to another cages containing the oviposition sites. To evaluate the effect of different sources of blood on A. aegypti, the percentage of engorged females, pre-oviposition time and the number of eggs per engorged female were measured. Highest percentage of engorged females were among mosquitoes fed on human citrated blood (89%) and control (95%). The media oviposition on both treatments were 13,4 eggs for females fed on human citrated blood and 15,3 eggs for females of control group. The lots fed on mice and bovine citrated blood presented the following results respectively: 22,5% of engorged females and 9,2 eggs per female and 25,8% of engorged females and 10,3 eggs per female. / Foi comparado o efeito do sangue de camundongos, bovino e humano sobre o ingurgitamento e oviposi??o do mosquito Aedes aegypti L., 1762 (D?ptera:Culicidae). O aparato para alimenta??o artificial foi constitu?do por gaiolas de pl?stico, com 10 x 6 cm, com orif?cios laterais cobertos com tela de tule, e uma abertura superior, atrav?s da qual foi oferecido o sangue contido em uma c?lula montada em l?mina de microscopia com cola de silicone e membrana de silicone. O sangue foi mantido aquecido a 37,5 ? 0,5 ?C, durante o tempo de alimenta??o que variou de 20 a 30 minutos. O experimento foi conduzido dentro de uma c?mara climatizada, com temperatura de 28 ? 0,5 ?C, umidade relativa de 80 ? 5% e fotoperiodismo de 12 horas di?rias. Um total de 16 grupos de 30 f?meas de A. aegypti, com idades entre 4 a 7 dias, foram pr?-alimentados com solu??o a?ucarada de sacarose. Em cada grupo foram adicionados 10 machos para realiza??o de c?pula. O sangue de cada hospedeiro foi coletado assepticamente e adicionado de citrato de s?dio a 3,9%. O grupo controle foi alimentado diretamente em hospedeiro humano volunt?rio. Ap?s a alimenta??o, as f?meas ingurgitadas foram contadas e colocadas no interior de gaiolas com 50 x 50 x 50 cm, contendo frasco com ?gua limpa para oviposi??o. Foram registrados o n?mero de f?meas alimentadas em cada tratamento, o per?odo de pr?-postura e o n?mero m?dio de ovos por f?mea alimentada. Mosquitos alimentados com sangue de camundongos e de bovino tiveram performances de 22,5 e 25,8% de ingurgitamento e a postura foi em m?dia de 9,2 e 10,3 ovos por f?mea, respectivamente. F?meas alimentadas com sangue humano atrav?s da membrana ou diretamente no hospedeiro humano tiveram comportamentos diferentes com ?ndices de ingurgitamento de 89 e 95% e oviposi??o de, em m?dia, 13,4 e 15,3 ovos por f?mea, respectivamente. N?o houve varia??o no per?odo de pr?-postura (tr?s dias) entre os tratamentos realizados.
75

Manufacture and characterization of elastic interconnection microstructures in silicone elastomer

Dejanovic, Slavko January 2006 (has links)
The subject of this thesis is a new chip to substrate interconnection technique using self-aligning elastic chip sockets. This work was focused on the technology steps which are necessary to fulfill in order to realize the suggested technique. Elastic chip sockets offer a solution for several assembly and packaging challenges, such a thermo-mechanical mismatch, effortless rework, environmental compatibility, high interconnection density, high frequency signal integrity, etc. Two of the most challenging technology aspects, metallization and etching of the silicone elastomer were studied, but also, air bubble free casting of the silicone elastomer was taken into consideration. Elastic chip sockets and single elastic micro-bump contacts of different shapes and sizes were manufactured and characterized. The contact resistance measurements revealed that the elastic micro-bump contacts manufactured by using the developed methods require less than one tenth of the contact force to achieve the same low contact resistance as compared to commercial elastic interconnection structures. The analysis and measurements of the high frequency properties of the elastic micro-bump structures have shown that they can operate up to several tens of GHz without a serious degradation of the signal quality. The same methods were applied to manufacture very high density contact area array (approximately 80000 connections/cm2), which until now was achieved only using so called chip-first techniques. The low contact resistance, the absence of environmentally harmful materials, no need of soldering, easy rework as well as capability of very high interconnecting density and very high frequency compatibility, indicates a high potential of this technique for assembly and packaging. Moreover, the presented technology of the silicone elastomer micromachining (metallization and RIE in particular) can be used for manufacturing of other microstructures, like chemical or biological micro reactors. / QC 20110114
76

Manufacture and Characterization of Elastic Interconnection Micro-

Dejanovic, Slavko January 2006 (has links)
<p>The subject of this thesis is a new chip to substrate interconnection technique using self-aligning elastic chip sockets. This work was focused on the technology steps which are necessary to fulfill in order to realize the suggested technique. Elastic chip sockets offer a solution for several assembly and packaging challenges, such a thermo-mechanical mismatch, effortless rework, environmental compatibility, high interconnection density, high frequency signal integrity, etc.</p><p>Two of the most challenging technology aspects, metallization and etching of the silicone elastomer were studied, but also, air bubble free casting of the silicone elastomer was taken into consideration. Elastic chip sockets and single elastic micro-bump contacts of different shapes and sizes were manufactured and characterized.</p><p>The contact resistance measurements revealed that the elastic micro-bump contacts manufactured by using the developed methods require less than one tenth of the contact force to achieve the same low contact resistance as compared to commercial elastic interconnection structures.</p><p>The analysis and measurements of the high frequency properties of the elastic micro-bump structures have shown that they can operate up to several tens of GHz without a serious degradation of the signal quality.</p><p>The same methods were applied to manufacture very high density contact area array (approximately 80000 connections/cm2), which until now was achieved only using so called chip-first techniques.</p><p>The low contact resistance, the absence of environmentally harmful materials, no need of soldering, easy rework as well as capability of very high interconnecting density and very high frequency compatibility, indicates a high potential of this technique for assembly and packaging.</p><p>Moreover, the presented technology of the silicone elastomer micromachining (metallization and RIE in particular) can be used for manufacturing of other microstructures, like chemical or biological micro reactors.</p>
77

Contribution à l'étude de l'anisotropie induite par l'effet Mullins dans les élastomères silicones chargés / A contribution to the study of induced anisotropy by Mullins effect in silicone rubber

Machado, Guilherme 12 May 2011 (has links)
Le présent travail étudie la caractérisation expérimentale et la modélisation de l'anisotropie induite par effet Mullins, i.e., la perte de raideur après les premiers cycles de chargement, très souvent observée dans les matériaux de type élastomère. Après une description des caractéristiques mécaniques du matériau silicone utilisé dans notre étude, des essais expérimentaux originaux sont développés pour créer des historiques de chargement complexes. D'une part, des successions d'essais de traction uniaxiale classiques sont réalisées, avec changement de directions de chargement. D'autre part, des états hétérogènes de contrainte et déformation obtenus lors d'essais de gonflement de membrane circulaire ont été complètement caractérisés grâce à des mesures de champs cinématiques réalisées par la méthode de corrélations d'images 3D ; les chargements effectués sont alors de type traction biaxiale-traction simple. Les paramètres clés pour la modélisation de l'effet Mullins ont ainsi pu être mis en évidence, avec notamment ses parts isotrope et anisotrope. Un modèle a ainsi été développé à partir d'une théorie de double réseau prenant en compte des critères expérimentalement motivés. Une version adaptée à une implantation simple dans un code de calculs éléments finis est finalement développée pour la réalisation de calculs de structures. / The present work studies the experimental characterization and modeling of the anisotropy induced by Mullins effect, i.e., the loss of stiffness in the first loading cycles, often observed in rubber-like materials. After a description of the mechanical characteristics of the particular silicone material used in our study, experimental tests are developed to create original and complex loading histories. First, successions of conventional uniaxial tensile tests are performed with changing directions of loading. Second, the state of heterogeneous stress and strain obtained in circular membrane swelling tests was completely characterized by means of kinematic field measurements made by the 3D image correlation method, and the loadings are then biaxial tension followed by uniaxial traction. The key parameters for modeling the Mullins effect were able to be identified, including its isotropic and anisotropic parts. A model was thus developed based on the double-network theory taking into account the experimentally motivated criteria. A suitable version with simple implementation in a finite element computer code was finally developed to allow the calculation of a structural part.
78

Avaliação dos elásticos ortodônticos intra-orais de látex e de borracha sintética: estudo in vitro e in vivo / Evaluation of orthodontic intraoral latex elastic and synthetic rubber: study in vitro and in vivo

Daniela Ferreira de Carvalho Notaroberto 25 February 2014 (has links)
Os elásticos ortodônticos intermaxilares sintéticos vem sendo cada vez mais utilizados, sendo principalmente indicados para pacientes que apresentam hiper-sensibilidade ao látex. Afim de avaliar e comparar o comportamento de elásticos de látex e sintéticos quanto a perda de força ao longo do tempo, este estudo foi realizado tanto in vitro quanto in vivo. Para o estudo in vitro foram avaliados 15 elásticos de cada material, para cada tempo: 0, 1, 3, 12 e 24 horas. No estudo in vivo, pacientes foram avaliados (N=15), utilizando elásticos de ambos os materiais (látex e sintético), nos mesmos tempos do estudo in vitro. Os elásticos foram transferidos para a máquina de ensaios mecânicos (EMIC DL-500 MF). Os valores da força gerada foram registrados após a distensão dos elásticos a uma distância de 25mm. Foi aplicado o teste t pareado para a amostra clínica e independente para a amostra laboratorial. Foi utilizada a análise de variância (ANOVA) para verificar a variação das forças geradas entre os tempos determinados e o teste post-hoc para identificar entre quais tempos houve diferença significativa. Quanto às forças iniciais geradas (zero hora), os valores para os elásticos sintéticos foram bastante semelhantes entre os estudos laboratorial e clínico e ligeiramente superiores aos dos elásticos de látex. Nos tempos subsequentes, as forças geradas pelos elásticos de látex apresentaram valores superiores. Em relação à degradação do material, ao final de 24 horas, maior percentual foi observado para os elásticos sintéticos, tanto in vitro quanto in vivo. A maior queda nos valores das forças liberadas pelos elásticos de ambos os materiais e nos estudos clínico e laboratorial, ocorreu entre os tempos de 0 e 1 hora, seguida de uma queda gradativa e progressiva até o tempo de 24 horas. Os elásticos de látex apresentaram um comportamento mais estável no período estudado em relação aos sintéticos, em ambos os estudos. / Synthetic intermaxillary orthodontic elastics are being increasingly used and they are primarily indicated for patients with hypersensitivity to latex. In order to evaluate and compare the behavior of latex and synthetic elastics, as the loss of strength, over time, this study was conducted both in vitro and in vivo. For the in vitro study, 15 of each elastic material was evaluated for each time: 0, 1, 3, 12 and 24 hours. For the in vivo study, patients were evaluated (N = 15) using both elastic materials (latex and synthetic) at the same times settled in vitro study. The rubber bands were transferred to the testing machine (EMIC DL-500 MF). The values of the force were recorded after stretching the elastic to a length of 25mm. Matched to the clinical and independent for laboratory sample t test was applied. Analysis of variance (ANOVA) was used to check the variation of the forces generated between those determined times and the post-hoc test to identify between which times were marked difference . As regards the initial forces (time zero), the values for synthetic elastic were quite similar between laboratory and clinical studies and slightly higher than the latex elastic. In subsequent times, the forces generated by the latex elastic showed higher values. Regarding the material degradation at the end of 24 hours, the highest percentage was observed for synthetic elastic, both in vitro and in vivo. The largest drop in the values of forces unleashed by the elastic of both materials and the clinical and laboratory studies occurred between times of 0 and 1 hour, followed by a gradual decreases until the time of 24 hours. The latex elastic had a more stable behavior during the period studied compared with synthetic, in both studies.
79

Implante de tubo de silicone com e sem colágeno na regeneração de nervos de eqüinos

Delistoianov, Nádia [UNESP] 07 December 2007 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:31:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-12-07Bitstream added on 2014-06-13T20:41:22Z : No. of bitstreams: 1 delistoianov_n_dr_jabo.pdf: 990663 bytes, checksum: 3bdef122463c6cc7df0f1f90e609da41 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A reparação de nervos em seres humanos, em cães e em diversos animais de laboratório é bastante utilizada e tem indicações clínicas e experimentais. Em eqüinos, relata-se formação de neuromas e excessiva proliferação de tecido conjuntivo. O presente estudo teve o objetivo de acrescentar informações sobre o processo de regeneração de nervos periféricos em eqüinos por meio de implante de tubo de silicone preenchido ou não com colágeno. Para tanto foram utilizados oito eqüinos, alocados em dois grupos: GI – 13 semanas e GII – 26 semanas de observação. Foi realizada a fixação parcial dos nervos ulnares (nn.u) e dos ramos cutâneos laterais dos 17° nervos torácicos (nn.t) ao tubo de silicone, bilateralmente, seguido de secção completa e reparação, realizada em cada animal, alternando-se tubos de silicone vazios (TS), em um dos antímeros, e preenchidos com solução de colágeno (TSC), nos nervos contralaterais, deixando-se espaço de 5mm entre os cotos. Avaliaram-se os animais semanalmente pelo teste de sensibilidade cutânea da região inervada pelos respectivos nervos e exame físico do aparelho locomotor até o final do período de observação. Não foram observadas alterações no exame físico do aparelho locomotor e as primeiras reações positivas ao teste de sensibilidade cutânea nos nn.u e nos nn.t reparados com TS e TSC, foram observadas a partir da 9ª semana, em ambos os grupos. Ao final do período de observação, verificou-se, macroscopicamente, que os nervos encontravam-se envolvidos por tecido conjuntivo e o interior da câmara preenchido por tecido de coloração esbranquiçada, de forma cilíndrica, interligando os cotos proximal e distal. Microscopicamente, constatou-se a presença de axônios mielinizados interligando os cotos, células de Schwann e processo de remielinização do coto distal, principalmente nos nervos com TSC... / Nerve repair in humans, dogs and laboratory animals is widely utilized on clinical and experimental purposes. Neuroma and excessive conjunctive proliferation are reported in horses. The aim of the present study was to add information about the regeneration process utilizing implant of silicone tubes with or without collagen in nerve regeneration. Eight horses were allocated in two groups: GI – 13 weeks and GII – 26 weeks of observation. A complete section of the ulnar nerves (unn.) and of the lateral cutaneous branch of 17° thoracic nerves (tnn.), bilaterally, was followed by repair with silicone tubes filled (STF) or not with collagen (ST), with a 5mm gap between stumps. Alternates STF and ST were utilized in each animal. Clinical evaluation was made weekly, by cutaneous sensitivity testing of the region innervated by the operated nerves and physical examination of the thoracic limbs. No alterations were found in the locomotor apparatus. The first positive reactions to the cutaneous test occurred at the 9° week post surgical. At the end of the observation period it was verified, grossly, that the nerves were involved by conjunctive tissue and the lumen of the tube was filled by whitish tissue, in a cylindrical shape. The ends nerves were interconnected. Microscopically, myelinated axons and Schwann cells were present in the gap between the stumps. The distal nerve showed remyelination process. In the nerves with STF the process was more conspicuous...(Complete abstract, click electronic access below)
80

Estudo comparativo das propriedades físicas, químicas e biológicas de próteses mamárias de silicone.

GOMES, Allysson Antônio Ribeiro. 12 July 2018 (has links)
Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-07-12T11:18:08Z No. of bitstreams: 1 ALYSSON ANTÔNIO RIBEIRO GOMES - DISSERTAÇÃO (PPGCEMat) 2015.pdf: 3273281 bytes, checksum: b71940c4b95418d315f4cfe0dfe1600a (MD5) / Made available in DSpace on 2018-07-12T11:18:08Z (GMT). No. of bitstreams: 1 ALYSSON ANTÔNIO RIBEIRO GOMES - DISSERTAÇÃO (PPGCEMat) 2015.pdf: 3273281 bytes, checksum: b71940c4b95418d315f4cfe0dfe1600a (MD5) Previous issue date: 2015-06-11 / Os implantes mamários são dispositivos médicos, empregados para aumentar, reconstrutir ou corrigir anomalis congênitas mamárias. Normalmente, são preenchidas por gel de silicone e/ou solução salina. Atualmente, têm sido utilizados com frequência implantes mamários com a superfície externa da membrana texturizada, por apresentar maior seguraça e reduzir complicações pós-operatórias como as contraturas capsulares. Desta forma, este trabalho teve como objetivo avaliar as propriedades físicas, químicas e biológicas de implantes mamários com membrana texturizada e preenchidas com gel de silicone. Portanto foram analisados quatro implantes mamários, de dois diferentes fabricantes, sendo uma marca nacional e outra importada. Os ensaios de caracterização foram realizados no lado da membrana interno que fica em contado com o gel e no lado externo que fica em contato com o meio biológico, através das seguintes técnicas: Microscopia Óptica – MO, Microscopia Eletrônica de Varredura – MEV, Espectroscopia por Energia Dispersiva de Raios X - EDS, Retilineidade, Ensaios Dimensionais - Espessura, Ensaio Mecânico - Tração, Citotoxicidade e Coesividade do Gel. Nos resultados do ensaio de avaliação morfológica (MO e MEV) foi observado que a superfície das membranas em contato com o gel apresenta-se com textura lisa e uniforme já o lado externo da membrana observou-se presença de poros com tamanhos e formas bastante distintas. Em relação aos ensaios mecânicos, todas as amostras atenderam aos requisitos normativos, porém uma das amostras apresentou valor muito próximo do limite de aprovação. Observou-se que a texturização das superfícies influencia nos desempenhos mecânicos das membranas. Os resultados do ensaio de coesividade do gel de preenchimento, citotoxicidade e de elementos químicos contaminantes foram semelhantes em todas as amostras e estão de acordo com as normas de certificação, sendo X2 muito próximo ao limite de aprovação. / Silicone breast implants are medical devices used to increase, reconstruct or correct mammary congenital deformities. Typically, they are filled with silicone gel and / or saline solutions. Currently, there is often used breast implants with the outer surface of the textured membrane to present maximum security and reduce post-operative complications such as capsular contracture. Thus, this study aimed to evaluate the physical, chemical and biological properties of textured silicone gel breast implants. Four breast implants were analyzed, two different manufacturers. The characterization tests were performed on the inner side of the membrane which is in contact with the gel, and the external side, in contact with the biological environment, through the following techniques: optical microscopy - MO, Scanning Electron Microscopy - SEM, Spectroscopy Energy Dispersive X-ray - EDS, Straightness, Dimensional Testing - Thickness, Mechanical Testing - Traction, Cytotoxicity and cohesiveness gel. The results of the morphological evaluation test (OM and SEM) it was observed that the surface of the membrane in contact with the gel appears with smooth and uniform texture, however, the external side of the membrane was observed pores with very different sizes and shapes . Regarding the mechanical tests, all samples met the regulatory requirements, but one of the samples showed a value close to approval limit. It was observed that the texturing of suferfícies influences the mechanical performances of the membranes. The cohesiveness filling gel test, cytotoxicity and chemical contaminants were similar in all samples and comply with certification regulations.

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