Made available in DSpace on 2014-10-09T12:27:22Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:37Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

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Made available in DSpace on 2014-10-09T12:27:22Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:37Z (GMT). No. of bitstreams: 0 / Os nódulos de tireóide constituem patologia comum, com uma incidência entre 4- 7% na população brasileira. Embora a punção aspirativa por agulha fina (PAAF) seja um método com boa sensibilidade, a discriminação entre lesões benignas e neoplasias malignas não é possível em todos os casos, permitindo a incidência de diagnósticos falsos-positivos, o que conduz a tireoideotectomia pelo risco de carcinoma. O escopo deste estudo foi verificar se a espectroscopia de absorção no infravermelho por transformada de Fourier (FTIR) pode contribuir no diagnóstico diferencial entre neoplasias malignas e benignas de tecidos e aspirados. Amostras de PAAF, homogenatos e tecidos de nódulos de tireóide com o diagnóstico histopatológico foram obtidos e preparados para análise espectroscópica por FTIR. As punções e homogenatos foram medidas por -FTIR (entre 950 1750 cm-1, com resolução de 4 cm-1 e 120 varreduras). As amostras de tecido foram analisadas diretamente pela técnica de ATR-FTIR, com resolução de 2 cm-1, 60 varreduras, região entre 950 1750 cm-1.. Todos os espectros foram corrigidos pela linha base e normalizados pela área sob a banda das amidas (1550-1640 cm-1) de modo a minimizar as variações de homogeneidade das amostras. Os espectros foram então convertidos em segundas derivadas usando-se o filtro de Savitzk-Golay com 13 pontos na janela. A variância de Ward e distância euclidiana foram usadas para se processar a análise de clusters. As amostras de PAAF revelaram um complexo padrão espectral. Todas as amostras mostraram alguns aglomerados de células ou grande concentração de hormônios, tendo representação em algumas bandas em 1545 e 1655 cm-1. Foram também encontradas bandas em torno de 1409, 1412, 1414, 1578 and 1579 cm-1, indicando a possível presença de açúcares, DNA e ácido cítrico de produtos metabólitos. Neste estudo, foi obtida uma excelente separação entre bócio adenomatoso e neoplasias malignas para as amostras de tecido, com 100% de sensibilidade em determinado cluster, mas 67% no geral e 50% de especificidade. Nos homogenatos e aspirados este valor foi menor (76,2% de sensibilidade e 52,6% de especificidade) porque incluiu outros tipos de lesões. Para uma maior diferenciação das amostras de PAAF de padrão folicular, um maior número de amostras se faz necessário. Os resultados deste estudo sugerem que a espectroscopia FTIR pode ser útil na diferenciação de carcinomas da tiróide em amostras de tecidos. / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

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The diploma thesis deals with the design of a system for measuring infrared spectra from local areas of samples. The theoretical part describes the electromagnetic waves and related phenomena. Furthermore, the semiconductor junction and solar cells are discussed. The following is a basic description of line spectrometers. In the practical part, a suitable arrangement of the whole system, collimator design, and especially the core of the whole work, ie control software and signal processing, are proposed.

Mass spectrometers have proven to be vital to understanding the Solar System and the planets within it. Spacecraft containing mass spectrometers have been sent to numerous remote places and have determined important information about the atmospheric composition of Venus, Earth, Mars, Jupiter, and Saturn, along with other celestial bodies. Such results have shown a variety of small neutral molecules, such as CH4 NH3, H2O, CO2, and CO, neutral radicals such as atomic O, H, and N, and a host of small ions, such as H+, N+, and NH4+. Closed ion source inlets, which allow for the detection of these small neutral molecules, contain a spherical antechamber that allows the neutrals to thermalize with the walls of the chamber through many successive collisions before they are introduced into the ionization region of the spacecraft mass spectrometer. These collisions, however, energetically excite neutral molecules and lead to many chemical changes, such as racemization, ionization, or even dissociation. When these changes occur, smaller neutrals can be produced, even if they were not in the original sample from the atmosphere or surface. As a result, the determination of the true composition of an atmosphere or a surface is cast into doubt. Herein is given a brief description of mass spectrometry in space research and how the closed ion source has greatly assisted this process. Dissociation and other chemical changes caused by the high velocity impacts that occur in closed source antechambers is also addressed. A theoretical approach to understanding such dissociative processes that occur after high energy collisions in closed source antechambers is described and undertaken. Chapter 2 describes a proof-of-concept study using hexane as a representative molecule and determines the velocity at which widespread dissociation of hexane molecules is likely to occur in closed source antechambers. This same theoretical process is then utilized in Chapter 3 with many more members of the n-alkane family to probe what effect molecular weight has on the amount of dissociation. Alkanes of both higher and lower molecular weight than hexane (C6H14) are used to show the effect as a function of molecular weight. In all cases, it was found that the velocity at which half of the incoming neutral n-alkane molecules dissociate is roughly the same for all molecular weights studied. This result is then applied to current and future space research through a proposed hardware solution, which will reduce the amount of dissociation and a discussion of how this effect may be seen in the results obtained from future mission instruments. Lastly, future work with different molecular weights and with successive collisions (the second, third, fourth, etc.) is described. This future work will further expand the present study to show how different functional groups, which may be partly responsible for higher-than-expected levels of NH3 and CO2, are affected after a high velocity, high energy impact.