Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 6 uppsatser.

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Orientador: Marcelo Coelho Goiato / Abstract: The purpose of this study was to analyse the influence of time exposure to the environmental factors, chemical disinfection with 2% chlorhexidine-based solution and two distincts pigments about dimensional changing and maintenance of details of two silicones for use in maxillofacial prosthesis. Thirty specimens were fabricated for each silicone using a matrix, conformed closely to the specifications for nonaqueous, elastomeric dental impression materials established by the Revised American Dental Association n° 19 and the ISO 4823:1984. Specimens were separated in three groups: control (colourless), pigmented with commercial cosmetic (makeup powders) and pigmented with iron oxid. Specimens were analysed in a comparator microscopic (Carl Zeiss) and stereoscopic loupe. The readings were realized after polymerization of the specimens, and after 30 and 60 days, with and 157 without disinfection. The data were submited to the statistic analysis, by the Tukey's Test. The results indicated that all groups presented contraction; the chemical disinfection only changed the dimensional stability of the Silastic cosmetic pigmented group; the dimensional stability of Silastic was affected after 60 days of exposition in all groups. For the Brascoved silicone, the chemical disinfection only didn't have influence about dimensional stability in initial period; the exposition factor had influence about the dimensional stability of Brascoved in all periods and groups. The details were maintained in all specimens for both silicones, independent of the exposition time, of the pigments or disinfection. / Mestre

Resumo: O dióxido de carbono (CO2) é um importante gás de efeito estufa. No entanto, um aumento gradual ameaça substancialmente o clima. Um dos principais desafios do planejamento ambiental é identificar um modelo que vincule todos os fatores do ciclo de carbono, ou seja, oceano - ecossistema terrestre - emissão antropogênica - atmosfera. Princípios básicos de Termodinâmica podem ser aplicados em uma modelagem estatística com bases em séries históricas para obter concentrações de CO2 na atmosfera, possibilitando a construção de cenários para uma melhor tomada de decisões. Por este motivo, foi desenvolvido no trabalho um modelo que interliga todos os fatores do ciclo de carbono, focalizando em quatro zonas térmicas ou climáticas (Boreal, Temperada, Tropical, Polar), para cálculos de armazenamento de CO2 atmosférico. Os resultados mostram que no ano 2100 se atingirá uma concentração de CO2 quatro vezes maior do que antes do período pré-industrial. A zona temperada emite quase a metade de dióxido de carbono à atmosfera na atualidade; para o ano 2100, essa emissão aumentará a quinze vezes mais que a zona tropical. A China será responsável em uma proporção de vinte quatro a onze com relação aos Estados Unidos. A estabilização das concentrações de CO2 na atmosfera será obtida quando as emissões de dióxido de carbono antropogênico tiverem uma diminuição de mais do que trinta e quatro por cento para o ano 2100 na zona temperada. / Abstract: Carbon dioxide (CO2) is the most important greenhouse gas. A gradual increase on its atmospheric concentration threatens significantly the climate. One of the main challenges of environment planning is to identify a model that connects all factors that determine the carbon cycle, that is, ocean - terrestrial ecosystem - anthropogenic emissions - atmosphere. Basic thermodynamic principles can be applied in a statistical modeling with historic time series to obtain atmospheric CO2 concentration, creating the possibility of construction of scenarios that will help decision making. A model that links all carbon cycle factors was developed in this dissertation work, focusing in four thermal of climatic zones (Boreal, Temperate, Tropical, and Polar) for calculations of atmospheric CO2 storage. Results show that in 2100, the atmospheric CO2 concentration will reach a value four times higher than that of the pre-industrial period. The temperate zone already emits almost half of the carbon dioxide to the atmosphere; by 2100, this emission will increase 15 times more than that corresponding to the tropical zone. China will be responsible for emissions in a proportion of 24 to 11 in comparison to that of the United States. Stabilization of CO2 concentrations in the atmosphere will be obtained when the anthropogenic carbon dioxide emissions attain a decrease of at least 34% in 2100 in the temperate zone. / Orientador: Sérgio João Crnkovic / Coorientador: Humberto Lopes Rodrigues / Banca: Antonio Jorge Abdalla / Banca: Marcelo dos Santos Pereira / Banca: Sandra Giacomin Schneider / Banca: Leonardo Gonçalves Cunha / Doutor

Orientador: Lafayette Nogueira Júnior / Banca: Tarcísio José Arruda de Paes Junior / Banca: Argemiro Soares da Silva Sobrinho / Resumo: Esta pesquisa se propôs verificar a manutenção do torque, após fadiga mecânica, de parafusos de pilares protéticos com recobrimento de carbono tipo diamante (DLC) e com dopagem de diamantes (CD-DLC) submetidos ao retorque, em conexões hexagonais externa (HE) e interna (HI). Implantes HE e HI e diferentes tratamentos do parafuso protético foram alocados em grupos experimentais (n = 5): sem tratamento e não submetidos a fadiga (HE-CON) (HI-CON); sem tratamento fadigados (HECONF) (HI-CONF); com DLC fadigado (HE-DLCF) (HI-DLCF) e com CDDLC fadigados (HE-CD-DLCF) (HI-CD-DLCF). Os recobrimentos de DLC e CD-DLC foram depositados a plasma pelo método PECVD. As amostras (implante + parafusos + coroa metálica), que já haviam sido expostas a 1 milhão de ciclos de fadiga, foram retorqueadas com torquímetro digital, com o torque recomendado pelo fabricante 30 N (HE) e 20 N (HI), e submetidos novamente a 1 milhão de ciclos mecânicos. Ao término da fadiga, os parafusos foram destorqueados para verificar a manutenção do torque. Parafusos de cada grupo experimental foram selecionados para observação em MEV. A análise estatística foi realizada pelo teste Anova 2- Fatores (α = 0,05). Não houve interação entre os fatores em estudo (p = 0,765); o tratamento dos parafusos (p = 0,638) e o tipo de conexão (p = 0,615) não apresentaram diferença estatística. Alterações como danos nas roscas do parafuso e remoção do filme foram observados entre os grupos experimentais. Os grupos com revestimento apresentaram pouco ou nenhum dano nas roscas dos parafusos. O revestimento de DLC e CDDLC parece não ter interferido na adaptação do parafuso ao implante. Parafusos protéticos recobertos com DLC e CD-DLC, após o retorque, não elevaram a manutenção do torque / Abstract: The study analyzed the torque maintain of the screw abutments, with coating of diamond-like carbon (DLC) and doping of diamond (CD-DLC), submitted the retorque in external hexagonal (EH) and internal (IH) connections; after mechanical fatigue. HE and HI implants and different treatments of the abutments screws were divided into experimental groups (n = 5): untreated and not subjected to fatigue (EH-CON) (IHICON); fatigued untreatment (EH-CONF) (IH-CONF); fatigued with DLC (EH- DLCF) (IH-DLCF) and fatigued with CD-DLC (EH-CD-DLCF) (IH-CD-DLCF). The DLC and CD-DLC coating was deposited by plasma, PECVD method. Samples (Implant + abutment screew + metal crown), which had been exposed to 1 million fatigue cycles were retorquiadas, digital torque wrench, to the torque recommended by the manufacturer 30 N (HE) and 20 N (HI), and submitted again to 1 million cycles mechanics. At the end of fatigue, the screws were destorquiados to check the maintenance of torque. Screws from each experimental group were selected for observation by SEM. Statistical analysis was performed by ANOVA 2 Factors test (α = 0.05). There was no interaction among the factors studied (p = 0.765); the treatment of screws (p = 0.638) and the connection type (p = 0.615) showed no statistical difference. The microscopy images showed damage the threads and covering the presence of HI connections. Changes such as damage on the screws threads and film removal were observed among the experimental groups. The coating groups showed little or no damage on the screws threads. The DLC and CD-DLC coating did not interfere in the screw adaptation on the implant. Abutments screew coating with DLC and CD-DLC, after retorque, no raised torque maintenance / Mestre

Thesis --(MSc. (Medical Physics)), 2009. / Introduction The primary role of breast cancer treatment with radiation is to deliver a sufficient radiation dose to the cancer cells without unduly causing biological damage to the healthy tissues. For over 50 years, electron beam therapy has been an important modality for providing an accurate dose of radiation to superficial cancers and disease and for limiting the dose to underlying normal tissues and structures in particular to boost the dose to the tumour bed and surgical scars after mastectomy. The Monte Carlo code MCNP5 was used to determine the effect of silicone gel breast prosthesis on the electron beam dose distribution. Materials and Method Percentage depth dose curves (PDD) for 6, 9, 12, and 15 MeV electron energies along the electron central axis depth dose distributions in a water phantom and with silicone prosthesis immersed in a water phantom were simulated using MCNP5. In order to establish the accuracy of the MCNP5 code, the depth dose curves obtained using MCNP5 were compared against the measured depth dose curves obtained from the Varian 2100C linear accelerator. The simulated depth dose curves with silicone prosthesis immersed in water were compared to the measured depth dose curves with the vi silicone prosthesis in water. The dose at the interface of the prosthesis with water was measured using thermoluminiscent dosimeters. Results The simulated and measured depth dose curve and the investigated dosimetric parameters are within 2%. Simulations in the presence of silicone showed a decrease in dose as the at the interface as the beam passes from the prosthesis to water for most energies however, for 15 MeV beam there is an increase in dose at the interface between the prosthesis and water and this was verified by physical measurements. Conclusion There were good correlations between the measured and MCNP simulated depth dose curve. Differences were in order of 2%. Small deviations occurred due to the fact that the simulations assumed a monoenergetic beam that exits the accelerator head, while in the measured results the beam exiting from the accelerator head includes scatted radiation from the collimators and the applicator. The presence of the prosthesis does not perturb the electron beam central axis depth dose curve however, the 15 MeV beam enhanced the dose in front of the interface between the prosthesis and water. Despite the limitations mentioned above MCNP5 results agree reasonably with the measured results. Hence, MCNP5 can be very useful in simulating electron percentage depth dose data.