Nanotechnology offers a great potential do design fertilizers with unique properties capable to boost the plant productivity. However, the nanoparticles environmental fate and their toxic responses still need to be deeply investigated to their safe use. This study aims to investigate the effect of copper oxide (nCuO) and magnetite nanoparticles (nFe3O4) on the germination and seedling development of Phaseolus vulgaris L. Seeds were treated in nanoparticles dispersions in a wide range of concentrations (1, 10, 100 and 1 000 mg L-1) and incubated in a germination chamber during 5 days. Different sized nCuO (25, 40 and <80 nm) and polyethylene glycol (PEG) coated nFe3O4 were evaluated. Although both nCuO and nFe3O4 treatments did not affected the germination rate, seedling weight gain was promoted by 40 nm CuO at 100 mg Cu L-1 and inhibited by 1 000 mg Cu L-1 of 25 nm CuO and positive control (CuSO4). Among the tested nCuO, the higher chemical reactivity was found for the 25 nm CuO, and this may partially explain the observed deleterious effects. Seeds treated in nFe3O4-PEG at 1 000 mg Fe L-1 increased radicle elongation compared to the negative control (water), while Fe2+/Fe3+ (aq) (positive control) and bare nFe3O4 at 1 000 mg Fe L-1 treatments reduced the radicle of the seedlings. The growth promoted by the PEG-coated nanoparticles can be justified by the higher water uptake induced by the PEG, and also by its lower chemical reactivity compared to the bare nanoparticles. This was reinforced by enzymatic assays since nFe3O4-PEG treatment was also the least harmful to the alpha-amylase activity. X-ray fluorescence spectroscopy (XRF) showed that most of the Cu and Fe incorporated by the seeds remained in the seed coat, specially in the hilum region, and X-ray tomography indicated that Fe3O4-PEG penetrated in this structure. X-ray absorption spectroscopy (XAS) unraveled that the Cu and Fe chemical environment of the nCuO and nFe3O4-PEG treated seeds persisted mostly in its primitive form. These results contribute to the understanding of how nCuO, nFe3O4 and nFe3O4-PEG interact with common bean seeds and seedlings and highlights its potential use in seed priming / A nanotecnologia oferece um grande potencial para o desenvolvimento de fertilizantes com propriedades únicas, capazes de impulsionar a produtividade das plantas. Contudo, o destino ambiental e os efeitos tóxicos das nanopartículas ainda necessitam ser profundamente investigados para o seu uso seguro. Este estudo visa investigar o efeito das nanopartículas de óxido de cobre (nCuO) e magnetita (nFe3O4) na germinação e desenvolvimento das plântulas de Phaseolus vulgaris L. As sementes foram tratadas em dispersões de nanopartículas em diversas concentrações (1, 10, 100 and 1 000 mg L-1) e incubadas em uma câmara de germinação durante 5 dias. Diferentes tamanhos de nCuO (25, 40 e <80 nm) e nFe3O4 recoberta com polietileno glicol (PEG) e foram avaliados. Embora ambos tratamentos de nCuO e nFe3O4 não afetaram a taxa de germinação, o ganho de massa das plântulas foi promovido pela nCuO de 40 nm à 100 mg Cu L-1 e inibido pelos tratamentos de nCuO de 25 nm e controle positivo (CuSO4) à 1 000 mg Cu L-1. Dentre as nCuO testadas, a maior reatividade química foi encontrada para a nCuO de 25 nm, e isso pode explicar parcialmente os efeitos deletérios desta nanopartícula. Sementes tratadas com nFe3O4-PEG à 1 000 mg Fe L-1 aumentaram o alongamento das radículas em comparação ao controle negativo (água), enquanto que os tratamentos Fe2+/Fe3+ (aq) (controle positivo) e nFe3O4 sem recobrimento à 1 000 mg Fe L-1 reduziram as radículas das plântulas. O crescimento promovido pelas nanopartículas recobertas com PEG pode ser justificado pela maior absorção de água induzido pelo PEG, e também pela sua baixa reatividade química comparada às nanopartículas sem recobrimento. Isso foi reforçado por ensaios enzimáticos uma vez que o tratamento de nFe3O4-PEG foi também o menos prejudicial à atividade da alfa-amilase. A espectroscopia de fluorescência de raios-X (XRF) mostrou que a maior parte do Cu e do Fe incorporados pelas sementes permaneceu no tegumento, especialmente na região do hilo, e a tomografia de raios-X indicou que nFe3O4-PEG penetrou nesta estrutura. A espectroscopia de absorção de raios-X (XAS) revelou que o ambiente químico do Cu e do Fe das sementes tratadas com nCuO e nFe3O4-PEG persistiram majoritariamente em sua forma primitiva. Estes resultados contribuem para o entendimento de como nCuO, nFe3O4 e nFe3O4-PEG interagem com sementes de feijão e destaca seu potencial uso no tratamento de sementes

Ce travail vise à contribuer à l’amélioration de notre connaissance de l’électrodynamique quantique des états liés, par des mesures de haute précision dans des états exotiques de la matière. Bien que notre connaissance de l’électrodynamique quantique des états liés et du problème relativiste à plusieurs corps aient fait des progrès importants ces dernières années, il reste des questions fondamentales dont la résolution nécessite d’augmenter le nombre et la précision des tests expérimentaux. La première partie de ce travail a été réalisée dans le cadre de l’expérience récente sur les ions muoniques d’hélium (μ4He+ et μ3He+) conduite par la collaboration CREMA. Cette expérience vise à fournir de nouvelles valeurs précises pour les rayons de charge moyens des noyaux des isotopes stables de l’hélium. Ces valeurs sont extraites de la mesure du déplacement de Lamb, c’est-à-dire, de la mesure de la différence d’énergie entre les États 2S − 2P. Une mesure des énergies de transition d’une précision d’au moins 50 ppm, permet de déterminer les rayons de charge des noyaux des isotopes d’hélium avec une incertitude de 0,03%, dix fois plus précise que les résultats précédents obtenus à partir de la diffusion d’électrons. La deuxième partie de ce travail a été de réaliser des mesures de haute précision de transitions de rayons X dans des ions fortement chargés, à l’aide d’un spectromètre à double cristal plan. Ces ions étaient produits dans le plasma d’une source d’ions de type ECRIS (electron-cyclotron resonance ion source). Le spectromètre utilisé est non seulement capable de fournir des mesures de haute précision, mais aussi des mesures sans référence à des énergies de transition théorique ou expérimentales. Quatre énergies de transition de n = 2 → n = 1 ont été mesurées pour des ions d’argon de trois états de charge différents, héliumoïde, lithiumoïde et berylliumoïde, avec une précision meilleure que 3 ppm. La largeur naturelle de chaque raie a également été obtenue expérimentalement. Les résultats trouvés sont en excellent accord avec les calculs théoriques les plus récents. / This work aims to provide insight on Bound-State Quantum-Electrodynamics (BSQED) by experimental fundamentals high-precision tests in exotic states of matter. Although BSQED and the relativistic many-body problem have been undergoing important progress, there are still some issues that require the increase of the number and accuracy of experimental fundamental tests. The first part of this work was done within the framework of the recent experiment in muonic helium ions (μ4He+ and μ3He+) by the CREMA collaboration. This experiment, aims to provide new accurate values for the root-mean-square (rms) charge radii of the helium isotopes nuclei that are extracted from the measurement of the Lamb Shift, i.e., the measurement of the energy difference between the 2S − 2P states. With the goal of measuring the transition energies with an accuracy of at least 50 ppm, the rms charge radii of the helium isotopes will be determined with an uncertainty of 0.03%, a factor of ten more precise than previous results obtained from electron scattering. The second part of this work aims the high-precision measurement of x-ray transitions in Highly-Charged Ions (HCI) using a Double-Crystal Spectrometer (DCS). These ions were produced in the plasma of an Electron-Cyclotron Resonance Ion Source (ECRIS). This kind of spectrometer is able not only to provide high-precision measurements but also reference-free measurements, without reference to any theoretical or experimental energy. Four transitions energies from n = 2 → n = 1 have been measured in an argon plasma in three different charge states, He-, Be- and Li-like, with an accuracy of better than 3 ppm. Besides the energies, the natural width of each transition has also been experimentally obtained. The obtained results are in excellent agreement with the most recent theoretical calculations.

For the automotive sector, plastics play the most important role when designing interior and exterior parts for cars. Currently, most parts are made from petroleum-based plastics but alternatives are needed to replace environmentally harmful materials while providing the appropriate mechanical performance and preferably reduce the cost for the final product. The objective of this work was to explore the use of soy flakes as natural filler in a composite with polypropylene and to investigate the mechanical properties, water absorption and thermal behaviour. For a better understanding of the filler, the soy flakes were characterized extensively with analytical and microscopic methods. Two types of soy fillers were investigated, soy flakes, provided by Bunge Inc., with a 48 wt-% protein content and an industrial soy based filler with 44 wt-% protein content and provided by Ford. The size of the soy flakes after milling was mainly between 50 and 200 µm and below 50 µm for the industrial filler. The aspect ratio for all filler was below 5. The soy flakes were used after milling and subjected to two pre-treatment methods: (1) one hour in a 50 °C pH 9 water solution in a 1 : 9 solid-liquid ratio; (2) one hour in a 50 °C pH 9 1M NaCl solution in a 1 : 9 solid-liquid ratio. A control filler, without pre-treatment was considered. The soy flakes were also compared to an industrial soy based filler provided by Ford (soy flour (Ford)). The thermogravimetric analysis showed an onset of degradation at 170 °C for the treated filler (ISH2O and ISNaCl) and 160 °C for the untreated filler. The biocomposites formulation consisted of 30 wt-% filler, and polypropylene with/without 0.35 wt-% anti-oxidant Irganox 1010 and with/without the addition of MA-PP as coupling agent. All biocomposites were compounded in a mini-extruder, pressed into bars by injection moulding and tested subsequently. The mechanical properties of the biocomposites are promising. An increase of the E-modulus was observed when compared to pure polypropylene. The addition of MA-PP as coupling agent increased the yield strength of the biocomposites. When pure polypropylene and the biocomposites were compared no difference could be seen for their yield strength. The thermal behaviour deduced from differential scanning calorimetry, revealed a similar behaviour for the biocomposites and the pure polypropylene. Only the samples treated in the presence of NaCl and without a coupling agent, appear to have a slightly higher degree of crystallinity. The melt flow index was slightly increased for the biocomposites containing soy flakes pre-treated with NaCl and decreased for biocomposites containing the soy flour. The water absorption behaviour of the biocomposites was quite similar at the beginning with a slightly lower absorption for the materials with coupling agent. After three months, all samples except the ones treated with water showed a weight loss that can be due to the leaching of the water soluble components in the untreated filler and the NaCl treated filler. In conclusion, soy flakes represent an attractive filler when used in a polypropylene matrix if an aqueous alkaline pre-treatment is performed. The aqueous alkaline extraction also leads to the recovery of the proteins that can be used in food products while the remaining insoluble material is used for the biocomposites, avoiding the competition with the use of soy for food products...

For the automotive sector, plastics play the most important role when designing interior and exterior parts for cars. Currently, most parts are made from petroleum-based plastics but alternatives are needed to replace environmentally harmful materials while providing the appropriate mechanical performance and preferably reduce the cost for the final product. The objective of this work was to explore the use of soy flakes as natural filler in a composite with polypropylene and to investigate the mechanical properties, water absorption and thermal behaviour. For a better understanding of the filler, the soy flakes were characterized extensively with analytical and microscopic methods. Two types of soy fillers were investigated, soy flakes, provided by Bunge Inc., with a 48 wt-% protein content and an industrial soy based filler with 44 wt-% protein content and provided by Ford. The size of the soy flakes after milling was mainly between 50 and 200 µm and below 50 µm for the industrial filler. The aspect ratio for all filler was below 5. The soy flakes were used after milling and subjected to two pre-treatment methods: (1) one hour in a 50 °C pH 9 water solution in a 1 : 9 solid-liquid ratio; (2) one hour in a 50 °C pH 9 1M NaCl solution in a 1 : 9 solid-liquid ratio. A control filler, without pre-treatment was considered. The soy flakes were also compared to an industrial soy based filler provided by Ford (soy flour (Ford)). The thermogravimetric analysis showed an onset of degradation at 170 °C for the treated filler (ISH2O and ISNaCl) and 160 °C for the untreated filler. The biocomposites formulation consisted of 30 wt-% filler, and polypropylene with/without 0.35 wt-% anti-oxidant Irganox 1010 and with/without the addition of MA-PP as coupling agent. All biocomposites were compounded in a mini-extruder, pressed into bars by injection moulding and tested subsequently. The mechanical properties of the biocomposites are promising. An increase of the E-modulus was observed when compared to pure polypropylene. The addition of MA-PP as coupling agent increased the yield strength of the biocomposites. When pure polypropylene and the biocomposites were compared no difference could be seen for their yield strength. The thermal behaviour deduced from differential scanning calorimetry, revealed a similar behaviour for the biocomposites and the pure polypropylene. Only the samples treated in the presence of NaCl and without a coupling agent, appear to have a slightly higher degree of crystallinity. The melt flow index was slightly increased for the biocomposites containing soy flakes pre-treated with NaCl and decreased for biocomposites containing the soy flour. The water absorption behaviour of the biocomposites was quite similar at the beginning with a slightly lower absorption for the materials with coupling agent. After three months, all samples except the ones treated with water showed a weight loss that can be due to the leaching of the water soluble components in the untreated filler and the NaCl treated filler. In conclusion, soy flakes represent an attractive filler when used in a polypropylene matrix if an aqueous alkaline pre-treatment is performed. The aqueous alkaline extraction also leads to the recovery of the proteins that can be used in food products while the remaining insoluble material is used for the biocomposites, avoiding the competition with the use of soy for food products...

Dans ce travail de thèse a été développé et étudié un nouveau type d'objet semiconducteur magnétique : des boîtes quantiques de CdMnTe insérées dans des nanofils de ZnTe/ZnMgTe constituant une structure de type cœur-coquille. L'objectif était d'étudier la croissance par épitaxie par jets moléculaires et les propriétés fondamentales de ces hétéro-structures complexes. Dans ce but deux aspects principaux ont été abordés : i) la qualité et le contrôle des propriétés structurales, électroniques et magnétiques de ces objets, grâce à une maîtrise de leur croissance et ii) l'obtention d'informations quantitatives locales sur la composition chimique de ces nanostructures inhomogènes. Pour atteindre ces objectifs, nous avons divisé notre étude en quatre étapes. La première étape de ce travail a été concentrée sur l'étude quantitative de la formation des particules d'or servant de catalyseurs à la croissance des nanofils. La seconde étape a porté sur l'analyse des mécanismes de croissance et des paramètres gouvernant la croissance des fils de ZnTe. En particulier deux types de fils ont été observés : des fils cylindriques de structure wurtzite et des fils coniques de structures zinc-blende. Un modèle de croissance guidée par la diffusion a été utilisé pour rendre compte de certains des résultats quantitatifs présentés dans cette partie. La troisième étape a concerné l'insertion de boîtes quantiques de CdMnTe dans des nanofils de structure cœur-coquille ZnTe/ZnMgTe. Une étude préalable des paramètres pertinents influençant les propriétés magnéto-optiques de ces objets, tels que le confinement de la boîte quantique, l'incorporation du Mn et l'anisotropie de contrainte créée par la structure, a été menée. La quatrième et dernière étape de ce travail a porté sur l'interprétation quantitative de mesures d'analyse dispersive en énergie effectuées sur des nanofils de structure cœur-multicoquille. Un modèle géométrique a été proposé, permettant de retrouver la forme, les dimensions et la composition chimique des boîtes quantiques et des coquilles. Cette étude a été couplée à des mesures de caractérisation telles que la cathodo-luminescence, la micro-photo-luminescence et la spectroscopie magnéto-optique effectuées sur le même nanofil. / In this PhD work a novel type of magnetic semiconductor object has been developed: Cd(Mn)Te quantum dots embedded in ZnTe/ZnMgTe core-shell nanowires. The goal was to investigate the growth, by molecular beam epitaxy, and the fundamental properties of these complex heterostructures. For that purpose, two main issues were addressed: i) gaining control of the structural, electronic and magnetic properties of these quantum objects by mastering their growth; and ii) obtaining quantitative local knowledge on the chemical composition of those non-homogeneous nanostructures. To tackle these topics, our research was divided into four stages. The first stage was devoted to perform a quantitative study of the formation process of the Au particles that catalyze the growth of nanowires. The second stage involved the analysis of the mechanisms and parameters governing the growth of ZnTe nanowires. In particular, two different types of nanowires were found: cone-shaped nanowires with the zinc-blende crystal structure and cylinder-shaped nanowires with the hexagonal wurtzite structure. A diffusion-driven growth model is employed to fit some of the quantitative results presented in this part. The third stage focused on the insertion of pure CdTe quantum dots containing Mn ions in the core-shell nanowires. An initial study of the relevant parameters influencing the magneto-optical properties of these objects, such as the quantum dot confinement, the Mn incorporation, and the strain anisotropy, was performed. The four and last stage of this work concerned the quantitative interpretation of Energy-Dispersive X-ray spectroscopy measurements performed on single core-multishell nanowires. A geometrical model was proposed to retrieve the shape, the size and the local composition of the quantum dot insertions and of the multiple layers of the heterostructures. This study was coupled to other complementary characterization measurements on the same nanowire, such as cathodo-luminescence, micro-photo-luminescence and magneto-optical spectroscopy.

Thesis (M.S.)--University of Missouri, School of Mines and Metallurgy, 1949. / Vita. The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed July 8, 2010) Includes bibliographical references (p. 65).

CAPES / Estudos realizados com cães apontam que dos grupos tumorais analisados, os de mama representam cerca de 25% a 50% dos tipos de tumores. Deste total, metade é considerado maligno. Apesar de representar um valor considerável de malignidade, estudos nesta área são poucos representativos e escassos na literatura. É de conhecimento que os tumores são causados por mudanças químicas e bioquímicas que ocorrem na célula. Atualmente, pesquisas são realizadas para entender o comportamento dessas alterações e por este motivo é de grande valia conhecer os elementos traço presentes nestes tecidos. Para esta finalidade a técnica mais empregada é a de ED-XRF (Fluorescência de Raios X de Dispersão de Energia), uma vez que é uma técnica analítica não destrutiva que permite determinar e quantificar a composição elementar das amostras, porém não identifica elementos com baixos números atômicos (menor que Z=10). Foram analisadas 56 amostras de tecido mamário canino benignas e malignas, fixadas em formalina a 10% tamponada e mantida à temperatura ambiente. Primeiramente para a quantificação dos elementos traço Ca, Fe, Cu e Zn foram determinadas as curvas de calibração de padrões diluídos em água, com concentrações de Ca, Fe, Cu e Zn, variando de 400 mg/kg a 35 mg/kg, de 20 mg/kg a 2 mg/kg, de 10 mg/kg a 1 mg/kg e de 100 mg/kg a 9 mg/kg, respectivamente. As medições foram submetidas à técnica de ED-XRF utilizando um tubo de raios X com ânodo de prata e técnica de exposição de 30 kV e 100uA e um tempo de exposição de 1000 segundos (incerteza ≤ 3%). O código XRMC (X-Ray Monte Carlo) foi utilizado para validação do método experimental, que tem o objetivo de simular computacionalmente as respostas esperadas para os ensaios experimentais validando assim a eficácia da metodologia. As concentrações dos elementos traço obtidas foram analisadas estatisticamente onde verificou-se uma variação significativa do elemento Zn, estando este presente em maior concentração no tecido mamário maligno do que no benigno. Este resultado pode estar relacionado à presença deste elemento nas matrizes de metaloproteinases, e em neoplasias malignas estão mais concentradas porque há característica de invasão tumoral neste tipo de neoplasia. Em outra comparação estatística pode-se verificar que os elementos traços Fe, Cu e Zn tem concentração equivalente tanto na região central do tumor tanto quanto na periferia, com exceção do Ca, este concentrando-se mais na região tumoral o que pode se dever às calcificações. Estudos nessa área são de grande potencial por permitir um melhor entendimento do processo patológico em tumores mamários caninos. / Studies with dogs show that the breast cancer represent about 25% to 50% of tumor types. Of this total, half is considered malignant. Despite representing a considerable amount of malignancy, studies in this area are few representative and scarce in the literature. It is known that tumors are caused by chemical and biochemical changes that occur in the cell. Currently, surveys are conducted to understand the behavior of these changes and for this reason, it is of great value to know the trace elements present in these tissues. For this purpose, the most common technique is to ED-XRF (X-Ray Fluorescence Energy Dispersion) since it is a non-destructive analytical technique to determine and quantify the elemental composition of the samples, although it doesn’t identify elements with low atomic numbers (less than Z= 10). Were analyzed 56 samples of canine breast tissue benign and malignant, fixed in 10% buffered formalin and kept at ambient temperature. First, for the measurement of trace elements Ca, Fe, Cu and Zn were determined standards for calibration curves diluted in water to concentrations of Ca, Fe, Cu and Zn, ranging from 400 mg/kg to 35 mg/kg, from 20 mg/kg to 2 mg/kg, from 10 mg/kg to 1 mg/kg and from 100 mg/kg to 9 mg/kg, respectively. Measurements were subjected to ED-XRF technique using an X-ray tube with silver anode and exposure technique of 30 kV and 100 uA and exposure time of 1000 seconds (uncertainty ≤ 3%). The XRMC code (X-Ray Monte Carlo) was used for validation of experimental method, which is intended to simulate by computer the expected responses for experimental tests, therefore validating the methodology efficiency. The concentrations of trace elements obtained were analyzed statistically where there was a significant variation of Zn element, the latter being present in higher concentration in malignant breast tissue than benign. This result may be related to the presence of this element in the matrix metalloproteinases, and malignant neoplasms are more concentrated because there are characteristic of tumor invasion in this type of neoplasm. In another statistical comparison it can be seen that the trace elements Fe, Cu and Zn is equivalent concentration both in the central region of the tumor as well as in the periphery, with the exception of Ca, this focusing more on the tumor region may be due to calcifications. Studies in this area are of great potential for allowing a better understanding of the disease process in canine mammary tumors.

A busca pela qualidade radiográfica com a menor dose de radiação absorvida é uma constante na comunidade radiológica. Juntamente com o princípio ALARA (As Low As Reasonably Achievable), os filtros de alumínio são peças fundamentais para barrar os fótons de baixa energia que não contribuem para a imagem e depositam dose de radiação para o paciente. De acordo com a Portaria n°453, a Agência Nacional de Vigilância Sanitária decretou que todos os equipamentos de raios X odontológicos intrabucais devem possuir a filtração adicional. Nesse sentido, os filtros são peças fundamentais para a proteção radiológica do paciente. Este estudo tem por objetivo caracterizar a composição elementar dos filtros de raios X de equipamentos de raios X odontológicos intrabucais. O estudo também relaciona a composição elementar com a qualidade das imagens radiográficas. A análise dos filtros foi realizada por meio do método de Espectroscopia de Fluorescência de raios X por Energia Dispersiva (EDXRF). Foram analisados, qualitativa e quantitativamente, dez filtros de alumínio. Para avaliar a qualidade das imagens, foram realizadas 30 radiografias periapicais dos dentes molares com 0,3 s de tempo de exposição (dez radiografias) e incisivos com 0,2 s e 0,3 s (vinte radiografias) com os diferentes filtros em um equipamento com os parâmetros de 66 kV e 6,5 mA. Os filtros e as radiografias foram identificadas, para que fosse possível distinguir a que filtro cada radiografia pertencia no momento das avaliações. Todas as radiografias foram feitas sob as mesmas condições. As radiografias foram submetidas à análise das densidades óticas por um densitômetro e posteriormente, enviadas a cirurgiões dentistas radiologistas que fizeram a análise subjetiva. Foram selecionadas três regiões para análise do densitômetro (diferenciadas entre dentes molares e incisivos) e uma região para análise subjetiva (diferentes regiões para dentes molares e incisivos). Os dados obtidos foram correlacionados com a avaliação dos efeitos da composição elementar dos filtros na qualidade das imagens radiográficas. Os elementos encontrados na análise dos filtros foram: Al, S, Cl, Ti, Mn, Fe, Cu, Zn e Zr. Os filtros apresentaram maiores concentrações de alumínio, com mais de 96% sendo os outros elementos contaminantes ou elementos que foram adicionados para melhorar a estabilidade mecânica do filtro. As densidades óticas das radiografias seguiram um padrão nas regiões analisadas, exceto as regiões enegrecidas do filme. A análise subjetiva revelou que muitas das radiografias realizadas poderiam ser aceitas para diagnóstico. Porém, imagens consideradas com baixo contraste obtiveram o mesmo valor de densidade ótica. Os resultados mostraram que a composição elementar dos filtros não modificou a qualidade da imagem. Por conseguinte, os filtros convencionais pesquisados oferecem uma opção aceitável para a produção de imagens de qualidade em radiologia odontológica, apesar das diferenças na composição das ligas. / The quest for radiographic quality with the lowest dose of radiation absorbed is a constant in the radiology community. Along with the ALARA principle (As Low As Reasonably Achievable), the aluminum filters are essential parts to bar the low energy photons do not contribute to the image and cause radiation dose to the patient. According to standard Portaria No. 453, the Agência Nacional de Vigilância Sanitária decreed that all equipment intraoral dental X-rays must have an additional filtration. Acording this, the filters are essential parts to radiological protection of patients. This study aims to characterize the elemental composition of filters used in intraoral X-ray equipment. We also intend to relate them to the quality of the radiographic images. The analysis of the filters was made using the method Energy Dispersive X-ray Fluorescence (EDXRF). Ten aluminum filters were analyzed (qualitatively and quantitatively). To evaluate the quality of images, 30 periapical radiographs of molars to 0.3 s (ten radiographs) and the incisor teeth 0.2 and 0.3 s (twenty radiographs) were performed with different filters. All filters and all radiographs were identified, it was possible to distinguish which folder each radiograph belonged at the time of the evaluations. All radiographs were performed under the same conditions. Radiographs were subjected to analysis of optical density by a densitometer and later, two dentists radiologists realized a subjective analysis. Three regions for analysis of the densitometer (differentiated between molars and incisors) and a region for subjective analysis (for different regions molars and incisors) were selected. The data were correlated with the assessment of the effects of the elemental composition of all filters in the quality of radiographic images. From the results, the elements of the filters in the analysis were: Al, S, Cl, Ti, Mn, Fe, Cu, Zn and Zr. The filters had higher aluminum concentrations (over 96%), other elements were contaminants or components that are added to improve the mechanical stability of the filter. The optical densities of radiographs followed a pattern for the regions analyzed except blackened regions of the film. Subjective analysis revealed that many of the radiographs were accepted for diagnosis. But considered low-contrast images obtained the same value of optical density. Therefore, it is concluded that the elemental composition of filters do not change the image quality. Consequently, conventional filters were evaluated option to produce an acceptable image quality in dental radiology, despite differences in the composition of the alloys.

CAPES / O câncer de mama deve atingir cerca de 57.120 novos pacientes no Brasil em 2014, como divulgado pelo serviço de epidemiologia do Instituto Nacional de Câncer. Pesquisadores têm associado neoplasias mamárias às alterações nas concentrações de alguns elementos no tecido da mama, tais como: cálcio, ferro, cobre e zinco. Neste sentido a técnica de espectroscopia por fluorescência de raios X surge como uma ferramenta para caracterização elementar deste tipo de tecido. A eficácia da referida técnica é fortemente dependente do espectro de raios X incidente na amostra, bem como do procedimento de calibração do sistema de medição. Neste trabalho foi avaliada a influência dos filtros de alumínio na eficiência de medição das concentrações dos elementos atrelados à neoplasias mamárias e avaliação das concentrações mínimas que o equipamento do Laboratório de Física Nuclear Aplicada da Universidade Tecnológica Federal do Paraná é capaz de registrar. O equipamento sobe investigação foi o da Amptek composto por um kit de um tubo de raios X modelo Mini-X e um detector do modelo X-123SD. Dos resultados, observou-se que para a quantificação dos referidos elementos simultaneamente, o uso de filtros de Al com espessura de 0,25 mm proporciona melhor eficácia na excitação dos mesmos. Além disso, foi verificado que são necessárias curvas de calibração específicas para cada elemento, as quais foram obtidas com cinco padrões biológicos da Agência Internacional de Energia Atômica. Os resultados permitiram comparar as concentrações dos padrões certificados aos obtidos pelos cálculos, assim como quantificar duas amostras de tecido mamário de características neoplásicas. / Breast cancer can reach around 57.120 new cases in Brazil in 2014, according the service of epidemiology in the National Cancer Institute. Researchers have been associated mammary neoplasm with changes of elements concentrations such as: calcium, iron, copper and zinc. In this way the technique of X-Ray Fluorescence appears like a tool to characterize this kind of neoplasm. The effectiveness of this technique is strongly dependent of X-ray spectrum incident on the sample as well as the calibration procedure of the measuring system. In present work, were evaluated the influence of aluminum filters on the measurement efficiency of the concentrations of the elements changed in mammary neoplasm and to evaluate the minimum concentrations that the equipment of the Laboratory of Applied Nuclear Physics at Federal University of Technology – Paraná is capable to register. The equipment under study was the Amptek kit of X-ray tube Mini-X and detector X-123SDD. The results obtained shown a simultaneous analysis, in that Al filters with thicknesses of 0.25 mm provides the best efficiency. Besides, it was verified that specifics calibration curves for each element was required, and it were obtained with five biological standards of International Atomic Energy Agency. The results made possible to compare the concentration of biological standards certificates with the equation obtained, in addition to analyze quantitatively two sample of breast tissue.

Cette thèse porte sur l’élaboration et la caractérisation électrique et physico-chimique des grilles métalliques des dispositifs FDSOI MOSFET 14 nm à base d’oxyde high-K fabriqués chez STMicroelectronics. Ces grilles métalliques sont composées de couches de TiN, lanthane et aluminium, déposées par pulvérisation cathodique RF. Des structures de test et un schéma d’intégration simplifié permettant l’analyse capacitive ont été mis en place pour caractériser la modulation du travail de sortie effectif des grilles métalliques en TiN avec l’incorporation d'additifs tels que le lanthane ou l’aluminium. Ces additifs ont été incorporés suivant une approche de grille sacrificielle. Par ailleurs, une méthodologie inédite basée sur la fluorescence X a été proposée et validée pour la caractérisation précise en ligne de la diffusion des additifs. Cette méthodologie permet de prouver que la dose effective de l’espèce incorporée après recuit de diffusion peut être modélisée en fonction de l’épaisseur du TiN piédestal dans la grille sacrificielle ainsi que de la température de recuit. De plus, la variation de l’épaisseur de l’oxyde interfaciel sur une seule plaquette (oxyde biseau) autorise l’identification de l’origine physique de la modulation du travail de sortie effectif, qui s’explique par un dipôle qui évolue avec la dose effective de l’espèce incorporée. En conséquence, un modèle de la diffusion des dopants de grille dans l’oxyde high-K et de leur impact sur le travail de sortie effectif des grilles métalliques a été proposé afin de moduler avec précision la tension de seuil (VTH) des dispositifs FDSOI 14 nm. En outre, l’impact de l’oxyde high-K à la fois sur la diffusion des additifs et sur la modulation du travail de sortie effectif a été mis en évidence. Enfin, un procédé innovant de dépôt métallique, permettant la modification de la microstructure du TiN, a été développé afin d’améliorer davantage la variabilité locale du VTH des dispositifs FDSOI. / This Ph.D. thesis is focused on the fabrication and electrical and physicochemical characterization of metal gates in 14 nm high-K based FDSOI MOSFET devices, manufactured at STMicroelectronics. These metal gates are composed of TiN, lanthanum and aluminum layers, deposited by RF sputtering. Test structures and a simplified integration scheme allowing C-V measurements, have been implemented in order to characterize the modulation of the effective work function of TiN metal gates with the incorporation of dopants such as lanthanum or aluminum. These additives are incorporated in a sacrificial gate-first approach. Furthermore, a new methodology based on X-ray fluorescence was proposed and validated for accurate in-line characterization of the diffusion of dopants. This methodology enables to prove that the effective dose of the species incorporated into dielectrics after diffusion annealing may be modeled as a function of the thickness of the pedestal TiN in the sacrificial gate and the annealing temperature. Moreover, the variation of the thickness of the interfacial oxide along the wafer (bevel oxide) authorizes the identification of the origin of the modulation of the effective work function, which is explained by a dipole that evolves with the effective dose of the incorporated dopant. Accordingly, a model of the diffusion of dopants into the gate dielectrics and their impact on the effective work function of metal gates has been proposed to precisely modulate the threshold voltage (VTH) of the 14 nm FDSOI devices. In addition, the influence of the high-K oxide on both the diffusion of dopants and the modulation of the effective work function was highlighted. Lastly, an innovative process for metal deposition, allowing the modification of the microstructure of TiN, was developed in order to further improve the local VTH variability in FDSOI devices.