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Made available in DSpace on 2014-10-09T12:49:45Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:07Z (GMT). No. of bitstreams: 1 10282.pdf: 3788200 bytes, checksum: 89ccf6d2ea9e26c2736dc1bbebcde360 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEn-CNEN/SP

Made available in DSpace on 2014-10-09T12:49:00Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:47Z (GMT). No. of bitstreams: 0 / Neste trabalho é descrito um procedimento para a determinação quantitativa da espessura e composição química de filmes finos, por fluorescência de raios X por dispersão de comprimento de onda (WDXRFS), utilizando-se o método de Parâmetros Fundamentais (FP). Este método foi validado dentro dos padrões de garantia de qualidade e aplicado as amostras de Al, Cr, TiO2, Ni, ZrO2 (monocamada) e Ni/Cr (duplacamada) sobre vidro; Ni sobre aço inoxidável e zinco metálico e TiO2 sobre ferro metálico (monocamada), as quais foram preparadas por deposição física de vapor (PVD). Os resultados das espessuras foram comparados com os métodos de Absorção (FRX-A) e Retroespalhamento de Rutherford (RBS), demonstrando a eficiência do método de parâmetros fundamentais. As características estruturais das amostras foram analisadas por difração de raios X (DRX) e mostraram que os mesmos não influenciam nas determinações das espessuras. / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Orientador: Silvana Moreira / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-19T05:19:51Z (GMT). No. of bitstreams: 1 Geraldo_SimoniMicheti_M.pdf: 8576780 bytes, checksum: 143842c5f48e40fb90b5def8331f572b (MD5) Previous issue date: 2011 / Resumo: Os metais podem ser introduzidos no ambiente naturalmente pelo intemperismo dos minerais e por fontes não naturais como fertilizantes, pesticidas, combustão de carvão e óleo, emissões veiculares, mineração, fundição, refinamento e incineração de resíduos urbanos e industriais. Atualmente muitos estudos utilizam os bioindicadores, plantas ou animais capazes de apresentar respostas qualitativas e/ou quantitativas, quando expostas a substâncias poluentes. As árvores registram e incorporam no seu lenho, desenvolvido ano após ano, as impressões do meio abiótico, tornando possível o estudo das diferentes alterações ambientais, entre elas a poluição, ocorridas ao longo da vida dessas árvores. A possibilidade de datação dos anéis de crescimento do lenho das árvores, aliada à aplicação das informações registradas em sua estrutura para estudos ambientais e históricos deu início à ciência chamada de dendrocronologia. A espécie selecionada para o estudo foi a Tipuana tipu. O presente trabalho teve como objetivo principal a determinação do teor de metais tóxicos em amostras de anéis de crescimento de árvores da espécie Tipuana tipu, previamente datados, coletadas nas regiões da Lapa, Pompéia, Sumaré, Butantã na cidade de São Paulo, através da técnica de Fluorescência de Raios X por Reflexão Total com Radiação Síncrotron. Foram realizadas coletas de anéis também no Campus da ESALQ/USP em Piracicaba (SP), local de pouco acesso e com baixo fluxo de veículos. Foram encontrados os seguintes elementos: K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, Sr, Ba e Pb. Alguns elementos traços apresentaram concentrações acima das consideradas normais em determinados períodos. Na cidade de São Paulo, a amostra 2 do Campus do IPT no Butantã foi a que apresentou maior toxicidade, com concentrações acima do limite tolerável para os seguintes elementos: Ti, Cr, Fe, Cu, Zn, Rb, Sr e Pb. Para as amostras coletadas no Campus da ESALQ em Piracicaba, a amostra 2 apresentou concentrações mais elevadas para a maioria dos elementos quando comparada as outras quatro amostras coletadas no mesmo local, ultrapassando os limites de toxicidade para: Cr, Fe, Ni, Cu, Zn, Sr e Pb. Pelos resultados obtidos podemos considerar que os anéis de árvore de crescimento da espécie Tipuana tipu podem ser utilizados como bioindicadores da contaminação ambiental / Abstract: Metals can be introduced in the environment naturally by the weathering of the minerals and by no natural sources as fertilizers, pesticides, oil and coal combustions, vehicular emissions, mining, foundry, refinement and incineration of urban and industrial wastes. Nowadays many studies use the bio-indicators, plants or animals capable to present qualitative and/or quantitative answers, when exposed to substances pollutant. Trees record and incorporate in their log, developed year after year, the impressions of the environment, becoming possible the study of the different environmental changes, including contamination, that have occurred over the life of these trees. The possibility to date the growth rings, combining with the information recorded in its structure to environmental and historical studies began to science called dendrochronology. The selected species, Tipuana tipu, of the Leguminosae family, is native of Argentina and Bolivia and was introduced in Brazil as ornamental. It is one of the most common trees in urban landscaping in Sao Paulo city. The present project has as main objective the determination of the content of heavy metals in samples of growth tree rings of Tipuana tipu, previously dated, collected in strategically locations of São Paulo, using Total Reflection X-Ray Fluorescence with Synchrotron Radiation (SR-TXRF). Samples were collected also in the Campus of ESALQ/USP, in Piracicaba (SP), local of little access and small flow traffic. The following elements were determined: K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, Sr, Ba, Pb. Some trace elements present concentrations higher than considered as normal in some periods. In São Paulo city, sample 2 collected in IPT Campus, Butantã, showed the highest toxicity, with concentration above the tolerable limit for the elements: Ti, Cr, Fe, Cu, Zn, Rb, Sr and Pb. For the samples collected in the ESALQ Campus, Piracicaba city, the sample 2 present highest concentrations for the majority of the elements when compared to the others four samples collected at the same place, exceeding the toxicity limits for: Cr, Fe, Ni, Cu, Zn, Sr and Pb. By the results obtained we can considerate that growth tree rings of Tipuana tipu specie can be used as bioindicators of environmental contamination / Mestrado / Saneamento e Ambiente / Mestre em Engenharia Civil

<p><b><i>Background and Objective:</i></b> Pb is a well-known toxic metal that can accumulate in bones over time and still threatening large populations nowadays, even those who are environmentally exposed to it. Strontium (Sr) is a metal directly related to bone health and has been used in the treatment of osteoporosis disease as a supplement. Manganese (Mn) is an essential nutrient in the body, yet excessive Mn is toxic and affecting many organ systems. Another toxic metal, mercury (Hg), has been poising different populations primarily through seafood consumptions, especially inducing neurological disorders in infants and fetuses. Even though significant associations between the above metal exposures and health outcomes have been recognized over the decades, the current technologies are limited in assessing cumulative long-term exposures <i>in vivo</i> to evaluate such associations further. Bone and toenail are appropriate biomarkers to reflect long-term exposure due to the longer half-life of these metals in them than in the traditional biomarkers. Therefore, this work evaluated the usefulness of portable x-ray fluorescence (XRF) technology on <i>in vivo</i> quantification of Pb and Sr in bone, and Mn and Hg in toenail.</p> <p><b><i>Materials and Methods:</i></b> The portable XRF device was calibrated by using the Pb- and Sr-doped bone-equivalent phantoms, and Mn- and Hg-doped nail-equivalent phantoms, correspondingly in different projects. Seventy-six adults (38-95 years of age, 63 ± 11 years) from Indiana, USA, were recruited to participate in this study. For the <i>in vivo</i> bone measurements, each participant was measured at the mid-tibia bone using the portable XRF and K-shell XRF system (KXRF). We estimated the correlation between the bone Pb concentration measured by both devices to evaluate the use of the portable XRF in the bones. Using the portable XRF, the bone Sr exposure of the study population were simultaneously assessed with the bone Pb exposures. Besides, we analyzed the mid-tibia bone Sr data of a Chinese population, which were measured with the same portable XRF device by our research group. We also examined the extent to which the detection limit (DL) of the portable XRF was influenced by scan time and overlying soft tissue thickness for both Pb and Sr. </p> <p>For the exposure assessment of Mn and Hg in toenails, we first established system calibrations and determined the DL with phantoms. In order to validate the portable XRF in a population study, the recruited participants were measured at the big toenail by the device, and their toenail clippings were analyzed by the inductively coupled plasma spectrometry (ICP-MS). Besides, we analyzed the toenail data of an occupationally-exposed population, collected by our collaborators in Boston. A portable XRF device with the same model as ours was used in that study. </p> <p><b><i>Results:</i></b> The uncertainty of <i>in vivo</i> individual bone measurement increased with higher soft tissue thickness overlying bone, and reduced with extending measurement time. With thickness ranging from 2 to 6 mm, the uncertainty of a 3-minute <i>in vivo</i> measurement ranged from 1.8 to 6.3 ug/g (ppm) for bone Pb and from 1.3 to 2.3 ppm for bone Sr. Bone Pb measurements via portable XRF and KXRF were highly correlated: R=0.48 for all participants, and R=0.73 among participants with soft tissue thickness < 6 mm (72% of the sample). A trend of different bone Sr concentrations was observed across the races and sexes. </p> <p>The DL of the portable XRF with 3-minute toenail measurements was 3.59 ppm for Mn and 0.58 ppm for Hg. The portable XRF and ICP-MS measurements were highly correlated in the occupational populations for both Mn (R = 0.59) and Hg (R = 0.75). A positive correlation (R = 0.34) was found for toenail Mn measurements in the environmentally-exposed population, while a non-significant correlation was observed for toenail Hg due to the extremely low-level of Hg (Mean = 0.1 ppm) in the study population. </p> <p><b><i>Discussion and Conclusion:</i></b> The portable XRF could be a valuable tool for non-invasive <i>in vivo</i> quantification of bone Pb and Sr, especially for people with thinner soft tissue; and of toenail Mn and Hg, especially for people with moderate- to high-level exposures. </p>

Iron overload conditions are a prevalent issue in global healthcare that require the accurate monitoring of iron levels to effectively provide treatment. X-ray fluorescence has emerged as a candidate for a point-of-care measurement tool for the detection of trace elements in vivo. This study explores the feasibility of a portable in vivo x-ray fluorescence (IVXRF) instrument using 125I as a point-of-care device in measuring skin iron levels. The system was calibrated using iron-doped water phantoms for various physiologically-applicable iron concentrations. Measurements were conducted on ex vivo rat skin samples (n = 34), which were then compared to a benchmark laboratory-based XRF system. Monte Carlo modelling using MCNP 6.2 was used to simulate the system in different conditions and provide an estimate of the radiation dose of the system on soft tissue. The R2 value for the calibration line of iron concentration in ppm to normalized iron signal was determined to be 0.985 (p < 0.01). For a measurement period of 1800 s real-time, the minimum detectable limit (MDL) of the system is 3.86 ± 0.06 ppm of iron. The R2 value for the linear regression between the IVXRF and benchmark XRF system normalized iron signals was 0.731 (p < 0.01). The R2 value for the linear regression between the IVXRF normalized iron signal and sample injected iron dose was 0.719 (p < 0.01), meaning the system can distinguish between different iron levels in rat skin. From the Monte Carlo simulations, the expected effective dose contribution from the IVXRF system is 101.68 ± 0.03 nSv. The IVXRF system was shown to accurately measure iron concentrations in ex vivo rat skin samples within the iron concentration ranges found within healthy and iron-overloaded patients. Further work shall be conducted to validate the system in in vivo applications. / Thesis / Master of Science (MSc) / Iron overload is a prevalent issue in healthcare, with many individuals experiencing detrimental symptoms, such as organ damage and heart failure. Modern treatment significantly improves quality of life but must be continuously monitored. This thesis covers the development of a non-invasive, cost-effective, and accurate system that can measure skin iron levels in patients to ensure effective monitoring. The results from this thesis suggest that the system can be used for clinical use to measure patient skin iron levels. It can theoretically measure iron in patients with normal and elevated iron levels. Simulation work suggests that the system will lead to negligible risk from radiation exposure. While this thesis and its findings support the feasibility of the system, further work is required before clinical implementation of the device.

<p> A method is presented for the determination of trace quantities of the rare earth elements and yttrium in calcareous minerals by X-ray fluorescence analysis. Initial chemical concentration of the rare earths is accomplished by scavenging their insoluble hydroxides on a ferric hydroxide precipitate and serves the further purpose of elimination of matrix absorption effects which dampen sensitivity when the raw minerals are analysed.</p> <p> Triplicate analyses are given for La, Ce, Sm and Y in a calcite-fluorite-apatite skarn rock and for each of the three minerals of this rock. Apatite and calcite are enriched in all the rare earths investigated relative to the whole rock, while fluorite shows a relative depletion. The apatite is enriched in the rare earths relative to the calcite. Peak height ratios of Nd, Eu, Er, Lu, Gd+Ho and Dy+Tm in each of the separated minerals to the whole rock show the same trends as the quantitative data and also indicate that apatite and fluorite show a stronger affinity for the lanthanides of low atomic number than for those of higher atomic number. The abundances of the rare earths in the apatite show the same dependence on ionic radius as has been noted by other workers. The whole rock and each of the minerals which it contains are enriched in all the rare earths relative to chondrites.</p> <p> The rare earths have preferentially entered the lattices of those minerals which provide a stronger rare earth-anion bond.</p> / Thesis / Bachelor of Science (BSc)

<p> X-ray fluorescence has been used to measure levels of lead in the bone for many years. This technique is particularly important for the occupational monitoring of those exposed to lead in the workplace as it provides an indication of long term exposure and retention in the body. The measurement of kidney mercury by x-ray fluorescence has been developed recently and is currently being improved for future use in occupational monitoring.</p> <p> X-ray fluorescence detection systems conventionally employ analog-amplifier components. Recently, digital spectrometers have been developed which can replace these conventional electronics components. The digital systems offer higher throughput without major losses in resolution which translates to better precision and reduced detection limits for x-ray fluorescence measurements.</p> <p> Investigations using the DSPECplus and DSA-2000 digital spectrometers for the measurement of bone lead in phantoms showed significant improvements in precision and potential reductions in MDL compared to conventional electronics. The use of the DSA-2000 digital spectrometer in a bone lead survey was shown to improve measurement uncertainties for in vivo bone lead measurements. Investigations using the DSA-2000 for the XRF measurement of kidney mercury in phantoms also showed a significant reduction in MDL for this system by the introduction of digital spectroscopy.</p> / Thesis / Master of Science (MSc)

<p> Samples from two granitic offshoot dikes from the Murray granite, and from the Murray granite itself were analysed for eight major elements using X-Ray Fluorescence, to determine whether or not the dikes represented remobilized parts of the Murray granite and as such could have a different chemical composition from the parent material.</p> <p> The analyses show that only very minor chemical differences exist between the two granitic dikes and the main Murray granite. However four samples of the dike rocks appear to show element exchange with the Sudbury norite surrounding them, resulting in increased Na2O and CaO contents and lower K2O contents, resulting in increased amounts of albitic plagioclase.</p> / Thesis / Bachelor of Science (BSc)