Thesis (doctoral)--Lunds Universitet, Malmö, 1998. / Added t.p. and errata sheet inserted. Includes bibliographical references.

Thesis (Ph. D.)--University of Alabama at Birmingham, 1999. / Includes bibliographical references.

Thèse (M.Sc.)--Université Laval, 2004. / Bibliogr.: f. 201-205. Publié aussi en version électronique.

Thesis (M.S.)--University of Michigan, 2001. / Includes bibliographical references.

There is growing interest in using large-scale observational data collected through national disease registries to develop clinical prediction models (CPMs) that use the experiences of past patients to make predictions about risks of outcome in future patients. CPMs are often developed in isolation across different populations, with repetitive de novo development a common modelling strategy. However, this fails to utilise all available information and does not respond to changes in health processes through time/space. Using the UK transcatheter aortic valve implantation (TAVI) registry as motivation, this thesis aimed to develop methods that improve the development of CPMs within local populations. Three research questions (RQs) were considered: (1) what are the challenges of mortality risk prediction in TAVI due to changes in procedure knowledge and the patient population? (2) Can we use a combination of baseline patient characteristics to predict the risk of mortality post TAVI? (3) How can we exploit multi-dimensional information about patients to inform clinical decision-making at a local-level? Chapter 2 demonstrates potential to simplify the procedure by removing pre-dilation of the aortic valve, thereby altering the underlying treatment pathway, and Chapter 3 shows that mortality rates from registries should be reported in the context of the underlying patient population. Despite Chapter 2 and 3 presenting potential challenges to TAVI risk prediction (RQ 1), CPMs are fundamental to support benchmarking/audit analyses. To this end, Chapter 4 found that the performance of existing TAVI CPMs was inadequate for use in UK patients. Through the discovery of new risk factors (e.g. frailty) in Chapter 5, the thesis derived a UK-TAVI CPM for audit analyses within the UK cohort (Chapter 6). While Chapters 4-6 present the classic framework of CPM development (RQ 2), this cannot overcome the challenges of mortality prediction in the TAVI setting (RQ 1) and is not suited to support local healthcare decision-making (RQ 3). Thus, Chapter 7 found that local model development could be supported through aggregating existing models rather than re-development. Existing methods of model aggregation were extended in Chapter 8 to allow prior research and new data to be utilised within the modelling strategy; application of the herein derived method to the UK TAVI registry indicated that it could facilitate the choice between model aggregation and de novo CPM derivation. Generally, this thesis has the potential to improve the implementation of CPMs within local populations by moving away from the iterative process of re-development. Practically, the thesis derived a UK-TAVI CPM for audit analyses, using classic and novel methodology.

Ion Implantation of ruthenium ions into a silicon substrate followed by a high temperature anneal (known as Ion Beam Synthesis) has been used for the first time to fabricate three wafers, under the following conditions. 1. 5.67 X 1016 Ru+ cm-2, beam heated 2. 4.25 X 1016 Ru+ cm-2, heated to ~ 600°C 3. 1.27 X 1017 Ru+ cm-2, heated to ~ 600°C All wafers contained precipitates of the orthorhombic semiconducting silicide of ruthenium, Ru2Si3. No other phase was identified. The samples exhibited a complicated microstructure, with 16 different orientation variants identified, and a high degree of disorder (~ +11% strain). The first optical measurements ever carried out on this material are reported here. Absorption measurements in transmittance yielded a direct band gap, in the region of ~ 0.9eV, 0.87eV, and 0.92eV for wafers 1, 2, and 3 respectively. No discernible variation of band gap magnitude with measurement temperature was found. Upon sequential annealing, the direct band gap magnitude remained constant up to ~ 650°C after which it shifted to above that of silicon, possibly due to a change in microstructural disorder as the precipitates increase in size. This observation was confirmed by several single step anneals at various temperatures above 650°C. No photoluminescence was observed in any of the samples.

Made available in DSpace on 2014-06-11T19:32:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-02-03Bitstream added on 2014-06-13T19:43:11Z : No. of bitstreams: 1 vasconcelos_lw_dr_araca.pdf: 3387652 bytes, checksum: 665ddeee618bbda24e7caff661ab090e (MD5) / Universidade Estadual Paulista (UNESP) / Brånemark et al. (1969) introduziram os implantes osseointegrados como forma de ancoragem para próteses com intuito de substituir os dentes perdidos, tanto na mandíbula como na maxila. Desde então, foram instituídas modificações no protocolo clássico. Entre elas, a submissão dos implantes à função imediatamente após a sua instalação. Esse procedimento tem sido largamente estudado na mandíbula, com altos índices de sucesso, contudo, a literatura é escassa quanto à aplicação desta técnica na maxila. Propôs-se, então, avaliar a função imediata em implantes instalados em maxilas desdentadas totais, no momento da cirurgia e após seis e 12 meses de função. Para tanto foi utilizada uma técnica cirúrgica modificada e a avaliação da estabilidade dos implantes foi feita por meio da análise da freqüência de ressonância. Foram selecionados 10 pacientes, nos quais foram instalados seis implantes na maxila com a submissão dos mesmos à função imediata mediante a instalação de uma prótese fixa, com infra-estrutura metálica, 24 horas após a cirurgia. Estes pacientes foram acompanhados por um período de 12 meses. As medidas da estabilidade do implante foram realizadas no momento da instalação dos implantes (M0) e após seis (M6) e 12 meses (M12). Após o período de acompanhamento, foram obtidos índices de sucesso de 95% para os implantes e 90% para as próteses. Quanto aos valores da estabilidade dos implantes, foi observada uma diferença estatisticamente significativa entre os valores de M0 e M6, e, M0 e M12. Sendo o M0, o momento com maior valor do coeficiente de estabilidade. Não houve diferença estatisticamente significativa entre os valores da estabilidade obtidos no M6 e M12. Quando comparados, o valor da estabilidade para cada implante, não apresentaram diferença estatisticamente significativa no mesmo período de avaliação... / Brånemark et al. (1969) presented the osseointegrated implants as a way to anchorage prosthesis for missing teeth substitution in the jaws. Ever since, modifications in the classical protocol were instituted. Among them, the functional loading of the implants, immediately after their installation. This procedure have been well documented in mandibles, with high success levels, however, literature is scarce about the application of this technique in maxilla. The purpose of this study is to evaluate the immediate function in implants installed in totally edentulous maxillas, at the surgical moment and after six and 12 months of function. For so much, a modified surgical technique was used and implant stability was evaluated through the resonance frequency analysis. Ten patients were selected, who received six implants installed in the maxilla and submitted to immediate function. A metallic infra-structure fixed prosthesis was installed 24 hours after the surgery. The follow-up period was of 12 months. Implant stability measurements were taken at the surgical moment (M0) and after six (M6) and 12 months (M12). After the follow-up period, success rates of 95% for implants and 90% for prosthesis were achieved. As for the implant stability values, significant statistical difference were observed between M0 and M6, and M0 e M12, and no significant statistical difference was observed between M6 and M12. When the stability values of each implant was compared, no significant statistical difference was observed between them for different evaluation periods. It is concluded that the submission of implants, installed in the maxilla through a modified technique, to immediate function is a well predictable procedure, ever since well selected and executed. The resonance frequency analysis is an efficient method for the evaluation of the initial and late implants’ stability.

Made available in DSpace on 2014-06-11T19:23:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-03-05Bitstream added on 2014-06-13T18:51:05Z : No. of bitstreams: 1 guastaldi_fps_me_araca.pdf: 881668 bytes, checksum: 3d7160f0119840f8c8f8a43bc927f885 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Proposição: Caracterizar, química e morfologicamente, superfícies de implantes constituídos de ligas de titânio/molibidênio (Ti-15Mo), modificadas por feixe de laser, comparando-as com implantes da mesma liga com superfície usinada, empregando-se análises biomecânica, histológica e histométrica. Material e método: Dezesseis coelhos receberam 1 implante por tíbia das seguintes superfícies: superfície usinada (SU) e superfície modificada por laser (SML). Após 8 semanas foi realizado o teste biomecânico em 6 animais. As amostras teciduais dos outros 10 animais foram submetidas à análise histológica e histométrica da interface osso-implante. As superfícies dos implantes foram analisadas por MEV e EDS, antes da realização do procedimento cirúrgico. Resultado: A caracterização da superfície mostrou uma topografia rugosa, regular e homogênea, promovida pela irradiação por laser. A análise por EDS mostrou ausência de contaminação da superfície pelo método de modificação. O resultado na remoção por torque, no período, foi 51,5 N.cm para SU e > 90 N.cm para SML. A análise histológica mostrou formação e um íntimo contato do tecido ósseo em 42% da superfície do implante SML, o que não foi constatado no implante SU (24%). Dados histométricos (BIC%) mostraram diferenças estatisticamente significativas entre o grupo SU e o SML, para o implante inteiro (p = 0.0012), as 3 melhores espiras consecutivas da região cortical (p = 0.0012) e o espaço medular (p = 0.0082). Conclusão: O tratamento a laser é um procedimento limpo, reprodutível e promove características físico-químicas e topográficas, importantes para a osseointegração. Os implantes de Ti-15Mo com SML apresentaram resultados biomecânicos, histológicos e histométricos superiores aos usinados / Purpose: Characterize, chemically and morphologically, implants surfaces of titanium/molybdenum alloy (Ti-15Mo), modified by laser beam, and comparing them with the same alloy implants with machined surface, using biomechanical, histological and histometric analysis. Material and method: Sixteen rabbits received 1 implant by tibia of the following surfaces: machined surface (MS) and laser-modified surface (LMS). After 8 weeks a biomechanical test was performed in 6 animals. The tissue samples of the other 10 animals were submitted to histological and histometric analysis of bone-implant contact. The surfaces of the implants were analyzed by SEM and EDX prior to the surgical procedures. Result: The characterization of the surface showed a rough, regular and homogeneous topography, caused by laser irradiation. The EDX analysis showed no contamination of the surface by the method of modification. Average removal torque in the period was 51.5 N.cm for MS and > 90 N.cm for LMS. Histological analysis showed bone formation and close contact of bone tissue on 42% of the LMS implant surface, which was not observed in the MS implants (24%). Histometric data (BIC%) showed statistically significant differences between the control and test group for the entire implant (p = 0.0012), the 3 best consecutive spires of the cortical (p = 0.0012) and medullary area (p = 0.0082). Conclusion: The laser treatment is a clean, reproducible procedure, and promotes important physico-chemical and topographic characteristics for osseointegration. The Ti-15Mo implants with LMS showed better biomechanical, histological and histometric results than the machined ones

Resumo: Filmes finos polimerizados a plasma apresentam várias aplicações nas indústrias óticas, elétrica, mecânica de alimentos, de biomateriais entre outras, devido suas interessantes propriedades químicas e físicas. No entanto, as aplicações para os filmes finos podem ser limitadas em função de algumas de suas características mecânicas e de superfície. Neste trabalho, filmes finos poliméricos foram depositados por radiofrequência a partir de plasmas de hexametildissilazano mantido a baixa pressão. Posteriormente, foram implantados íons de argônio, hélio e nitrogênio nestes filmes através da implantação iônica por imersão a plasma (IIIP). Após os tratamentos, os filmes finos provenientes da polimerização a plasma do hexametildissilazano apresentaram modificações em suas estruturas moleculares e composição química através das análises infravermelha e XPS. O XPS revelou um aumento nas concentrações de oxigênio e decréscimo de carbono e nitrogênio. Este fato indica aumento no nível e entrelaçamento, ramificação e reticulação das cadeias poliméricas para todos os íons implantados. Verificou-se também que a IIIP promoveu mudanças na molhabilidade com variações nos ângulos de contato de 100° para 10°; alterações nos índices de refração entre 1,65 a 2,10; modificações na dureza e módulo elástico de 0,8 a 3,3 GPa e 6,0 a 52,0 GPa respectivamente, assim como redução na taxa etching de 34,0 para 20,0 Å/min. / Abstract: Plasma polymerized thin films have many applications in optical, electrical, mechanical, food, biomaterial industries among others, due to their interesting chemical and physical properties. Polymer thin films applications, however, can be limited because of some mechanical and surface characteristics. In this work, thin polymer films were deposited from radiofrequency plasmas of hexamethyldisilazane at low pressure. Then, these films were implanted with argon, helium and nitrogen ion, by plasma immersion ion implantation (PIII). After the treatments, plasma polymerized hexamethyldisilazane thin films presented modifications in their molecular structure and chemical composition by infrared and XPS analysis. XPS revealed an increase in the oxygen, decrease in nitrogen and carbon concentrations. This fact indicates increased crosslinking of the polymeric chains of all implanted ions. It was also verified that a PIII caused modification in wettability, changing the contacts angles from 100° to 10°. Modifications were also observed in the refractive index from 1,65 to 2,10; in hardness and in the elastic modulus from 0,8 a 3,3 GPa and 6,0 to 52,0 GPa respectively. The study showed a decrease in etching rate from 34,0 to 20,0 Å/min. / Orientador: Rogério Pinto Mota / Coorientador: Deborah Cristina Ribeiro Santos / Banca: Roberto Yzumi Honda / Banca: Elson de Campos / Banca: Emerson Ferreira de Lucena / Banca: José Roberto Ribeiro Bortoletto / Doutor

Orientador: Paulo Sérgio Perri de Carvalho / Banca: Marco Antonio Bottino / Banca: Carlos Eduardo Francischone / Banca: Waldyr Antonio Janson / Banca: Per-Ingvar Branemark / Resumo: Brånemark et al. (1969) introduziram os implantes osseointegrados como forma de ancoragem para próteses com intuito de substituir os dentes perdidos, tanto na mandíbula como na maxila. Desde então, foram instituídas modificações no protocolo clássico. Entre elas, a submissão dos implantes à função imediatamente após a sua instalação. Esse procedimento tem sido largamente estudado na mandíbula, com altos índices de sucesso, contudo, a literatura é escassa quanto à aplicação desta técnica na maxila. Propôs-se, então, avaliar a função imediata em implantes instalados em maxilas desdentadas totais, no momento da cirurgia e após seis e 12 meses de função. Para tanto foi utilizada uma técnica cirúrgica modificada e a avaliação da estabilidade dos implantes foi feita por meio da análise da freqüência de ressonância. Foram selecionados 10 pacientes, nos quais foram instalados seis implantes na maxila com a submissão dos mesmos à função imediata mediante a instalação de uma prótese fixa, com infra-estrutura metálica, 24 horas após a cirurgia. Estes pacientes foram acompanhados por um período de 12 meses. As medidas da estabilidade do implante foram realizadas no momento da instalação dos implantes (M0) e após seis (M6) e 12 meses (M12). Após o período de acompanhamento, foram obtidos índices de sucesso de 95% para os implantes e 90% para as próteses. Quanto aos valores da estabilidade dos implantes, foi observada uma diferença estatisticamente significativa entre os valores de M0 e M6, e, M0 e M12. Sendo o M0, o momento com maior valor do coeficiente de estabilidade. Não houve diferença estatisticamente significativa entre os valores da estabilidade obtidos no M6 e M12. Quando comparados, o valor da estabilidade para cada implante, não apresentaram diferença estatisticamente significativa no mesmo período de avaliação...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Brånemark et al. (1969) presented the osseointegrated implants as a way to anchorage prosthesis for missing teeth substitution in the jaws. Ever since, modifications in the classical protocol were instituted. Among them, the functional loading of the implants, immediately after their installation. This procedure have been well documented in mandibles, with high success levels, however, literature is scarce about the application of this technique in maxilla. The purpose of this study is to evaluate the immediate function in implants installed in totally edentulous maxillas, at the surgical moment and after six and 12 months of function. For so much, a modified surgical technique was used and implant stability was evaluated through the resonance frequency analysis. Ten patients were selected, who received six implants installed in the maxilla and submitted to immediate function. A metallic infra-structure fixed prosthesis was installed 24 hours after the surgery. The follow-up period was of 12 months. Implant stability measurements were taken at the surgical moment (M0) and after six (M6) and 12 months (M12). After the follow-up period, success rates of 95% for implants and 90% for prosthesis were achieved. As for the implant stability values, significant statistical difference were observed between M0 and M6, and M0 e M12, and no significant statistical difference was observed between M6 and M12. When the stability values of each implant was compared, no significant statistical difference was observed between them for different evaluation periods. It is concluded that the submission of implants, installed in the maxilla through a modified technique, to immediate function is a well predictable procedure, ever since well selected and executed. The resonance frequency analysis is an efficient method for the evaluation of the initial and late implants' stability. / Doutor