no abstract provided by author / Master of Science

Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1979. / Includes bibliographical references. / by John Edward Pieszcynski. / Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1979.

O presente trabalho teve como objetivo analisar “in vitro” a alteração de cor e a rugosidade superficial de uma resina composta (Charisma®) submetidas a tratamento clareador com agente clareador Lase Peroxide Sensy® (CC) e grupo controle sem tratamento clareador (SCL), após envelhecimento (EAA) em função do tempo, realizando-se avaliação superficial complementar por meio de Microscopia Eletrônica de Varredura (MEV) e EDX. Os corpos-de-prova (n=15) foram confeccionados com o auxílio de uma matriz de Teflon nas dimensões de 11x2,0mm, polidos com discos Soft Lex®, na seqüência de abrasividade decrescente e armazenados em saliva artificial a 37ºC (±1ºC), até os momentos de serem submetidos aos tratamentos propostos e à realização das leituras de alteração de cor e rugosidade superficial, nos tempos: 24 horas após a confecção (T0), após envelhecimento artificial acelerado (T1), 24 horas após clareamento (T2), 7dias (T3) e 1 mês após clareamento (T4). As leituras de alteração de cor foram obtidas com o auxílio do aparelho Espectrofotômetro (PCB6807BYK GARDNER) e para as leituras de rugosidade superfícial foi utilizado o Rugosímetro Mitutoyo SJ201P. Os dados foram submetidos à Análise de Variância ANOVA (p≤0,05). Os resultados obtidos foram: a) o fator Tempo teve efeito estatisticamente significante sobre as variáveis ΔE* (T1=T2=T3; T1=T4), L* (T0<T1=T2=T3=T4), a* (T0>T1=T2; T1=T3=T4; T4>T2), b* (T0>T1=T2=T3; T4=T3=T1; T2<T4) e rugosidade superficial (μm) (T0<T1,T2,T3,T4; T1=T2; T1<T3=T4; T2=T3=T4; b) para o fator tratamento com relação a ΔE* e fator L*(CC>SCL), para os fatores a* e b*(CC<SC), c) a interação Tratamento x Tempo não apresentou diferença estatisticamente significante para as variáveis ΔE*, L*, a*, b* e rugosidade superficial, d) as superfícies após EAA apresentaram alterações d) não houve mudanças no EDX antes e após os tratamentos. Conclui-se que a resina Charisma®, apresentou alteração de cor (ΔE*>3,3) e uma estabilidade na rugosidade superficial a partir de T2. / The current study in vitro evaluated the color change and surface roughness of the composite resin Charisma® cleared with Lase Peroxide Sensy® (CCL) and control without bleaching (SCL) after accelerated artificial aging (EAA) as a function of time, performing additional surface evaluation by scanning electron microscopy (MEV) and EDX. To obtain the color change and surface roughness a Spectrophotometer (PCB 6807 BYK GARDNER) and rugosimeter (Mitutoyo SJ- 201P) were employed respectively. Measurements were carried out at five times: 24 hours after preparation (T0), after artificial accelerated aging (T1), 24 hours after bleaching (T2), 7days (T3) and 1 month after bleaching (T4). The specimens (n=15) were prepared with aid of a Teflon (10-mmin diameter and 2mm thick). The specimens were polished with discs Soft Lex®, following abrasiveness decreased, being stored in artificial saliva at 37ºC (±1ºC) until the time of undergoing the proposed treatments and the measurements. The data obtained were submitted to ANOVA parametric test (p ≤ 0.05). The results were: a) time factor had a statistically significant effect on the variables ΔE* (T1 = T2 = T3, T1 = T4), L*(T0 <T1 = T2 = T3 = T4), a* (T0 > T1 = T2; T1=T3 =T4, T4>T2), b* (T0> T1=T2=T3, T4=T3=T1; T2<T4) and roughness(μm) (T0<T1,T2, T3,T4; T1 = T2; T1<T3=T4; T2=T3=T4), b) for treatment factor ΔE* and L* (CC> SCL) for the factors a*and b* (CC <SC), c) Treatment x Time interaction showed no statistically significant difference for the variables ΔE*, L*, a*, b* and surface roughness, d) after EAA the surfaces change d) before and after EAA dont have changes. It is concluded that the resin Charisma®, presented color change (ΔE *> 3.3) and surface roughness stability from T2.

Made available in DSpace on 2016-08-10T10:55:28Z (GMT). No. of bitstreams: 1 Paula Lorenzoni Paste de Oliveira.pdf: 1048800 bytes, checksum: 578b18c5642e39d43d7fcc9b72357fc4 (MD5) Previous issue date: 2006-12-15 / Nowadays the high level of cholesterol is one of the illnesses that reach millions of people causing about 12 million deaths in many developed countries, being the main cause of deaths in developing countries. Various researches in the world had defined the reference values for the total cholesterol levels in the blood. The reference values for the cholesterol exam are: desirable smaller than 200; smaller than 200 and larger or equal to 239 moderate risk and high risk larger ou equal to 240. Currently the dosage is carried through by spectrophotometer that it is based on the analysis of the color concentration, such concentration is directly proportional to the dosage of cholesterol (mg/dL) found in the sample. With computers, several techniques are being improved to aid clinical diagnosis. The aim of our work was to develop a technique using Digital Image Processing to dose the cholesterol level in a sample. The ELISA microtiter plate was used to capture a digital image with cholesterol exams samples. From this image, techniques of image processing were applied to find out the cholesterol concentration. The results were compared by statistical analysis with the results found for the current technique (spectrophotometer). The correlation coefficient analysis was applied and the results found was -0,94 (IC 95% = -0,9668 the -0,9036, P smaller than 0,0001), demonstrating that the process of capture and analysis of the cholesterol images has a strong correlation with the current method. To validate the experiment a ROC curve of the test was constructed. The area under the ROC curve was of 0,868 (IC 95% = 0,798 the 0,920, P smaller than 0,0001) evidencing to be a method with good discriminatory power. These results demonstrate that the analysis and image capture process obtained the desired results. The method proposed is an alternative way to assist in the dosage of the total cholesterol and can be used to develop equipments at low cost. / Nos dias de hoje a hipercolesterolemia é um dos distúrbios metabólicos que atinge milhões de pessoas, causando cerca de 12 milhões de óbitos em diversos países desenvolvidos, sendo a principal causa de óbitos em países em desenvolvimento. Diversas pesquisas em várias partes do mundo definiram os valores de referência para os níveis de colesterol total no sangue. Os valores de referência para o exame de colesterol são: desejável menor que 200; risco moderado de 200 à 239 e alto risco maior ou igual a 240. Atualmente a dosagem é realizada pelo espectrofotômetro que se baseia na análise da concentração de cor, sendo diretamente proporcional à dosagem de colesterol (mg/dL) encontrada na amostra. Com a evolução da informática, várias técnicas estão sendo aprimoradas por meio do uso de computadores no auxílio ao diagnóstico clínico. Neste trabalho propôs-se desenvolver uma técnica utilizando processamento de imagens para dosar o nível de colesterol existente nas amostras. Utilizou-se uma placa de ELISA para realizar a captura de uma imagem digital com amostras de colesterol. A partir desta captura, aplicaram-se técnicas de processamento de imagens para encontrar a concentração de colesterol existente. Estes resultados então, foram comparados estatisticamente com os resultados encontrados pela técnica atual (espectrofotômetro). A análise de correlação foi efetuada e os resultados encontrados com os experimentos foram de -0,94 (IC 95% = -0,9668 a -0,9036, p menor que 0,0001). Esse trabalho sugere que o processo de captura e análise das imagens de colesterol tem uma correlação forte com o método atual. Para validar o experimento, construiu-se a curva ROC do teste. A área abaixo da curva foi de 0,868 (IC 95% = 0,798 a 0,920, p menor que 0,0001) evidenciando um bom poder discriminatório. Estes resultados demonstram que o processo de captura e de análise obtiveram os resultados esperados. O modelo proposto é um método alternativo para auxiliar na dosagem do colesterol total, podendo ser utilizado para desenvolver um equipamento de baixo custo.

Este trabalho se encontra dividido em duas partes. Em uma parte inicial, relatamos a construção e caracterização de um laser de centro de cor (LCC) com meio ativo de KCl:Li+, operando de forma sintonizável no infravermelho na região em torno de 2,7 um. São descritas três configurações distintas para a cavidade do laser, e fazemos um estudo comparativo do desempenho do LCC para os três casos. Na segunda parte, o laser de centro de cor foi transformado em um espectrofotômetro de duplo feixe de alta resolução (largura de linha OMEGA-V<O,2 cm-1), com o qual passamos a estudar amostras cristalinas de NaF multiplamente dopadas com impurezas moleculares OH- e monoatômicas Cu+. Relatamos novas características desse material, que surgem em virtude da interação entre as referidas impurezas. Dentre essas características, temos o surgimento de um espectro complexo de linhas deslocadas para menores energias com relação a banda de absorção do modo de estiramento do OH-. Parâmetros de anarmonicidade são analisados, os quais sugerem a existência de anarmonicidade elétrica em adição a anarmonicidade mecânica. Estudos da dependência das larguras das bandas de absorção com a temperatura juntamente com medidas de TSDC ( corrente de despolarização termo-estimulada), revelaram a existência de um comportamento diferente daquele de rotor quase livre encontrado para o OH- em vários halogenetos alcalinos. Os resultados mostraram que no cristal de NaF tanto o OH- isolado quanto o acoplado estão permanentemente orientados / This work has two parts. The starting one is related with the construction and characterization of a tunable color center laser (CCL) with an active medium of KCl:Li+ which works in the mid infrared region around 2,7 um. It is discussed three different configurations set up for the laser cavity, and the profile of each case is compared between each other. For the second part, the color center laser is used as the source of a high-resolution double beam spectrophotometer (line width OMEGA-V<O,2 cm-1). The spectrophotometer is used to study multiple doped NaF crystal samples, with OH- molecules and monoatomic Cu+ impurities. New optical properties are found due to assumed coupling interaction between both impurities, which gives rise to a more complex spectrum where several lines are displaced to lower energies relative to the main OH- stretching mode absorption. Some anharmonic effects are observed, which suggests the existence of electric anharmonicity added to the mechanical one. Further study of the bandwidth temperature dependence, together with thermally stimulated depolarization current measurements, reveal a different behavior of the usual OH- quasi-free rotor found in several alkali halides. The results show that for the NaF crystal the isolated and coupled OH- ions are permanently oriented

<p><font face="TimesNewRomanPSMT"> <p align="left">The aim of this study was to investigate the color stability of two provisional restorative materials used in crown and bridge cases upon exposure to different tea staining solutions and to evaluate the effectiveness of a polishing technique in removing the tea stains from the stained provisional restorative materials.</p> </font></p>

TiO2 in anatase form is the most widely studied material for photocatalytic reactions. Utilization of oxide support materials such as silica with suitable transparency within band gap range of TiO2 is promising technique to obtain efficient photocatalysts for many applications. In the present study, simultaneous co-hydrolyzation of tetraethyl orthosilacate (TEOS) and titanium tetrabutaoxide (TBOT) precursors were carried out in the presence of hydrochloric acid. The effects of washing with low vapor pressure solvent(n-octane), drying conditions, hydrothermal ageing and TiO2/SiO2 ratio on the catalyst structure and photocatalytic activity were studied. The samples were characterized by XRD, BET, DRIFTS techniques and the activity was measured for liquid phase room temperature oxy/demineralization of phenol under artificial solar irradiation. The reaction intermediates were followed by UV/vis spectrophotometer and HPLC. It was found that the hydrothermal treatment contributes better degree of crystalinity, higher surface area and thus photocatalytic activity compared to the samples which were synthesized with conventional drying at 100oC overnight. The formation of Ti-O-Si interface indicating the degree of dispersion was evidenced by DRIFTS technique for all hydrothermally tretated samples. The highest surface area and photocatlytic activity was observed with hydrothermally treated catalyst with TiO2/SiO2:0.34 composition.

Pharmaceuticals and personal care products (PPCPs) are widely used, resulting in trace amounts being detected in the aquatic environment. This presence is of human health and ecological concern and it is necessary to determine the best methods to eliminate them from our waters. The oxidation of PPCPs by permanganate was evaluated using a spectrophotometer to monitor permanganate reduction. Thirty-nine compounds were chosen to represent numerous classifications, including beta blockers, cephalosporins, fluoroquinolones, macrolides, non-steroidal anti-inflammatory drugs, phenol structures, polypeptides, sulfonamides, tetracyclines, and triazines. The reactivity of each compound was determined by measuring the absorbance of permanganate over time as it reacted with an excess of the compound. The absorbance data was fit to a pseudo-first-order reaction model that accounted for the growth of manganese dioxide colloids. The most reactive groups that reduced permanganate within minutes at pH 7.0 were the cephalosporins, phenol structures, and tetracyclines. The majority of the remaining pharmaceuticals and personal care products were moderately or weakly reactive (reducing permanganate within hours). Caffeine, carbadox, monensin, simetone, and tri(2-carboxyethyl)phosphine were poorly reactive (reducing permanganate over days). Metoprolol was the only selected compound that was determined to be potentially non-reactive (no reaction after 1 day). Polarizability and refractive index of the organic compounds showed significant positive correlations (R-squared > 0.50) with the first-order reaction rates for non-steroidal anti-inflammatory drugs and the phenol structures group. The half-life of each PPCP was determined based on a typical dosage of permanganate used for pre-oxidation. Eleven of the thirty-nine PPCPs had a half-life of less than thirty minutes (a typical contact time), indicating that oxidation by permanganate may be a viable option. There are many opportunities for further research in this area, including investigating more PPCPs, physicochemical property correlations, and the impact of water quality conditions

<p><font face="TimesNewRomanPSMT"> <p align="left">The aim of this study was to investigate the color stability of two provisional restorative materials used in crown and bridge cases upon exposure to different tea staining solutions and to evaluate the effectiveness of a polishing technique in removing the tea stains from the stained provisional restorative materials.</p> </font></p>

Orientador: Osmir Batista de Oliveira Junior / Banca: Letícia Chun Pei Pan / Banca: Celso Yamashita / Banca: Edson Alves Campos / Banca: Marcelo Ferrarezi de Andrade / Resumo: O objetivo deste trabalho foi avaliar o efeito do manchamento sobre a intensidade de fluorescência de resinas compostas, em função dos meios de imersão e do tempo. Para isso, foram selecionadas as seguintes resinas compostas: Filtek Supreme XT (3MESPE), 4 Seasons (Ivoclar Vivadent), Venus (Heraeus - Kulzer), Vit~l~escence (Ultradent) e Esthet-X (Dentsply). Foram selecionadas também as seguintes soluções: café, suco de laranja, refrigerante de cola, vinho tinto e saliva (controle). Para cada condição experimental foram confeccionados cinco corpos-deprova (n=5) em forma de disco medindo 10,0mm de diâmetro e 1,0mm de espessura, que permaneceram imersos em saliva artificial e mantidos em estufa a uma temperatura de 37ºC±1. Esses corpos-de-prova foram retirados da estufa três vezes ao dia para imersão nas soluções testadas, durante o período de cinco minutos. Após este período foram lavados em água corrente e novamente imersos em saliva artificial e mantidos em estufa, até o momento da mensuração da intensidade de fluorescência. As leituras foram realizadas em seis níveis de variação: T0 - após confecção dos corpos-de-prova sem imersão em saliva artificial; T1 - 24 horas após imersão em saliva artificial; T2 - 24 horas após imersão nas soluções; T3 - 07 dias após imersão nas soluções; T4 - 14 dias após imersão nas soluções e T5 - 21 dias após imersão nas soluções. Para a obtenção dos valores de intensidade de fluorescência foi utilizado um espectrofotômetro (Spex Triax Fluorolog 3) calibrado para que o raio incidente fosse emitido com um comprimento de onda de 390nm e para que todo o fenômeno de fluorescência fosse registrado em uma faixa compreendida entre 400nm e 700nm. Os resultados obtidos foram submetidos à Análise de Variância e ao Teste de Tukey a 5%. De acordo com os resultados observou-se que as soluções influenciaram... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of this study was to evaluate the effect of staining on the fluorescence intensity of composite resins, depending on the solutions and immersion time. The following composites were selected: Filtek Supreme XT (3MESPE), 4 Seasons (Ivoclar Vivadent), Vênus (Heraeus - Kulzer), Vit~l~escence (Ultradent) and Esthet-X (Dentsply). We also selected the following solutions: coffee, orange juice, cola soft drink, red wine and artificial saliva (control). For each experimental condition were made five specimens (n=5) in a disk shape measuring 10,0mm diameter and 1,0mm thickness. All the specimens were immersed in artificial saliva and kept in an incubator at a temperature of 37ºC±1. The specimens were removed from the incubator three times a day for immersion in the solutions tested, during the period of five minutes. After it was washed in running water and again immersed in artificial saliva, until the time of measurement of fluorescence intensity. The readings were taken at six levels of variation. T0 - 24 hours after preparing the specimens, T1 - 24 hours after immersion in artificial saliva, T2 - 24 hours after immersion in the solutions, T3 after seven days, T4 after fourteen days and T5 after 21 days. To obtain the values of fluorescence intensity, was used a calibrated spectrophotometer (Spex Triax Fluorolog 3) with an incident ray delivered with a wavelength of 390nm. The phenomenon of fluorescence was registered between 400nm and 700nm. The results were submitted to the analysis of variance and Tukey's test 5%. The results showed that the solutions influenced the intensity of fluorescence emitted by resin composites (p<0,05). Coffee was the higher staining solution, followed by red wine, orange juice, cola soft drink and artificial saliva. Regarding the time it was noted that after T2 there was a significant change in fluorescence emission... (Complete abstract click electronic access below) / Doutor