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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Material-Specific Computed Tomography for Molecular X-Imaging in Biomedical Research

Dong, Xu 08 April 2019 (has links)
X-ray Computed Tomography (CT) imaging has been playing a central role in clinical practice since it was invented in 1972. However, the traditional x-ray CT technique fails to distinguish different materials with similar density, especially for biological tissues. The lack of a quantitative imaging representation has constrained the application of CT technique from a broadening application such as personal or precision medicine. Therefore, my major thesis statement is to develop novel material-specific CT imaging techniques for molecular imaging in biological bodies. To achieve the goal, comprehensive studies were conducted to investigate three different techniques: x-ray fluorescence molecular imaging, material identification (specification) from photon counting CT, and photon counting CT data distortion correction approach based on deep learning. X-ray fluorescence molecular imaging (XFMI) has shown great promise as a low-cost molecular imaging modality for clinical and pre-clinical applications with high sensitivity. In this study, the effects of excitation beam spectrum on the molecular sensitivity of XFMI were experimentally investigated, by quantitatively deriving minimum detectable concentration (MDC) under a fixed surface entrance dose of 200 mR at three different excitation beam spectra. The result shows that the MDC can be readily increased by a factor of 5.26 via excitation spectrum optimization. Furthermore, a numerical model was developed and validated by the experimental data (≥0.976). The numerical model can be used to optimize XFMI system configurations to further improve the molecular sensitivity. Findings from this investigation could find applications for in vivo pre-clinical small-animal XFMI in the future. PCCT is an emerging technique that has the ability to distinguish photon energy and generate much richer image data that contains x-ray spectral information compared to conventional CT. In this study, a physics model was developed based on x-ray matter interaction physics to calculate the effective atomic number () and effective electron density () from PCCT image data for material identification. As the validation of the physics model, the and were calculated under various energy conditions for many materials. The relative standard deviations are mostly less than 1% (161 out of 168) shows that the developed model obtains good accuracy and robustness to energy conditions. To study the feasibility of applying the model with PCCT image data for material identification, both PCCT system numerical simulation and physical experiment were conducted. The result shows different materials can be clearly identified in the − map (with relative error ≤8.8%). The model has the value to serve as a material identification scheme for PCCT system for practical use in the future. As PCCT appears to be a significant breakthrough in CT imaging field, there exists severe data distortion problem in PCCT, which greatly limits the application of PCCT in practice. Lately, deep learning (DL) neural network has demonstrated tremendous success in medical imaging field. In this study, a deep learning neural network based PCCT data distortion correction method was proposed. When applying the algorithm to process the test dataset data, the accuracy of the PCCT data can be greatly improved (RMSE improved 73.7%). Compared with traditional data correction approaches such as maximum likelihood, the deep learning approach demonstrate superiority in terms of RMSE, SSIM, PSNR, and most importantly, runtime (4053.21 sec vs. 1.98 sec). The proposed method has the potential to facilitate the PCCT studies and applications in practice. / Doctor of Philosophy / X-ray Computed Tomography (CT) has played a central role in clinical imaging since it was invented in 1972. It has distinguishing characteristics of being able to generate three dimensional images with comprehensive inner structural information in fast speed (less than one second). However, traditional CT imaging lacks of material-specific capability due to the mechanism of image formation, which makes it cannot be used for molecular imaging. Molecular imaging plays a central role in present and future biomedical research and clinical diagnosis and treatment. For example, imaging of biological processes and molecular markers can provide unprecedented rich information, which has huge potentials for individualized therapies, novel drug design, earlier diagnosis, and personalized medicine. Therefore there exists a pressing need to enable the traditional CT imaging technique with material-specific capability for molecular imaging purpose. This dissertation conducted comprehensive study to separately investigate three different techniques: x-ray fluorescence molecular imaging, material identification (specification) from photon counting CT, and photon counting CT data distortion correction approach based on deep learning. X-ray fluorescence molecular imaging utilizes fluorescence signal to achieve molecular imaging in CT; Material identification can be achieved based on the rich image data from PCCT; The deep learning based correction method is an efficient approach for PCCT data distortion correction, and furthermore can boost its performance on material identification. With those techniques, the material-specific capability of CT can be greatly enhanced and the molecular imaging can be approached in biological bodies.
102

Characteristic Analysis of Acid Mine Drainage Precipitates for the Optimization of Rare Earth Extraction Processes

Saber, Scott William 25 October 2018 (has links)
Acid mine drainage (AMD) forms when sulfur bearing rocks such as pyrite, are exposed to air and water. The oxidation of these minerals leads to the generation of sulfuric acid, which in turn mobilizes metals such as iron, aluminum, manganese, and others. If left untreated, AMD can cause severe harm to the surrounding ecosystem. By law, mining companies are required to treat AMD, often by oxidizing the contaminated water, raising the pH with a chemical additive, and precipitating the metals out of solution. Recent studies at West Virginia University and Virginia Tech have shown that AMD and the treatment precipitates (AMDp) are enriched in rare earth elements (REEs). Given the importance of REEs to modern technology, as well as potential supply restrictions, subsequent research has attempted to identify promising methods to extract and recovery REEs from AMD and AMDp. Prior studies have shown that the physical characteristics of AMDp can vary considerably from site to site, and a robust processes scheme must account for any site-specific disparities. To better understand the inherent variability of AMDp, a scientific study was commissioned to investigate a standard method of characterizing AMDp for the optimization of rare earth extraction processes. The tests developed in this work define the total acid dose needed to dissolve AMDp at various target pH points. Through the course of the study, over 150 unique AMDp samples were evaluated, and comparative analyses were conducted on samples from different sites as well as replicate samples from the same sites. The resultant dataset was analyzed using an empirical model, and a statistical analysis was conducted to correlate the model parameters and other AMDp physical properties. Relationships between elemental assays, moisture, and fitting parameters of the empirical models were found. These results ultimately led to a recommendation for future treatment of AMD and prospective sites. / MS / Acid mine drainage (AMD) is a longstanding environmental issue that is caused when sulfur-bearing rocks are exposed to the environment during the mining process. By law, companies are required to treat AMD prior to discharging the water back into the environment. This treatment process creates a waste byproduct, AMD precipitate, that largely consists of metal hydroxides, including iron, aluminum, manganese, and others. Historically, AMD precipitate has been considered an undesirable waste that must be carefully disposed either in old mine workings or in permanent storage cells. However, recent research has shown that AMD precipitate contains elevated concentrations of rare earth elements (REEs). REEs are a group of chemically similar elements that are well known for their use in several modern technologies, including magnets, catalysts, glasses, light-weight metal alloys, and other high-tech uses. REEs are often sparsely concentrated in nature and rarely form ore deposits of a commercial grade. As a result, several private companies and government agencies have sought alternative sources of REEs. Prior research has shown that AMD precipitate may be a suitable alternative source; however, the chemical and physical nature of AMD varies considerably between different sites. This research seeks to utilize a standard characterization test to identify the characteristics of AMD precipitate that ultimately dictate process amenability. Throughout the course of the study, over 150 unique AMD precipitate samples were analyzed, and the cumulative results show which class of sites constitute the most promising prospecting targets.
103

Determinação de cobre, cromo e arsênio em madeira preservada (Eucalyptus sp.) pelas espectrometrias de fluorescências de raios X / Cu, Cr and As determination in preserved woods, Eucaliptus ssp, by x-ray fluorescence spectrometries

Pereira Junior, Sergio Matias 08 December 2014 (has links)
O Brasil produz cerca de 2,2 milhões de metros cúbicos de madeira preservada para atender à demanda anual nos setores de transporte ferroviário, elétrico, rural e de construção civil. As espécies de madeiras mais usados são do eucalipto (Eucalyptus sp.) e pinus (Pinus sp.). A madeira preservada, utilizada para postes, dormentes, mourões e nas construções em madeira, deve estar em conformidade com as especificações exigidas pelas normas brasileiras quanto ao seu tratamento preservativo. No Brasil, os preservativos de madeira mais utilizados e regulamentados são CCA (arseniato de cobre cromatado) e o CCB (sal de cobre cromo e boro). As técnicas analíticas como espectrometria de absorção atómica de chama (FAAS) e espectrometria de emissão de plasma acoplado (ICPOES) e espectrometria de fluorescência de raios x (XRFS) são utilizadas para a avaliação desses processos. Neste trabalho, as amostras de madeira foram obtidas de árvores de eucalipto (Eucalyptus sp.), provenientes de áreas de plantação do estado de Minas Gerais, Brasil. Amostras de madeira de eucalipto foram submetidas a diferentes concentrações de solução de CCA, sob pressão, atingindo retenções de 3,9; 6,7; 9,1; 12,4 e 14,0 kg de CCA por m-³ de alburno. A partir dos blocos tratados foram obtidos amostras em forma de cilindros e serragem. A determinação de cobre, cromo e arsênio foi realizada pela espectrometria de fluorescência de raios X de energia dispersiva (EDXRF), espectrometria de fluorescência de raios X portátil (PXRF), FAAS e IAAN. Neste trabalho, foram avaliados métodos de análise, sensibilidade e precisão, exatidão das técnicas analíticas relacionadas. / Brazil produces around 2.2 millions of cubic meters of treated wood to meet the annual demand of railway, electric, rural and construction sectors. The most used wood species are eucalyptus (Eucalyptus ssp.) and pine (Pinus ssp.).The treated woods used for poles, sleepers, fence posts and plywoods should be according to Brazilian norms requirements. The most usual wood preservative products used in Brazil are CCA (chromated copper arsenate) and CCB (copper chromium and boron salt). The analytical methods, such as flame atomic absorption spectrometry (FAAS), plasma inductively coupled optical emission spectrometry (ICPOES) and X-ray fluorescence spectrometry (XRFS) have been used for the analytical control of those treatment processes. In this work, the eucalyptus trees (Eucalyptus ssp) samples was obtained from Minas Gerais State, Brazil, cut plantation areas. Under pressure, eucalyptus wood samples were submitted to different concentration of CCA solution reaching 3.9, 6.7, 9.1, 12.4 and 14.0 kg of CCA by m-³ sapwood retentions. Samples in cylinders and sawdust forms were obtained from treated wood samples. Copper, chromium and arsenic determination was performed using the energy dispersive X-ray fluorescence spectrometry (EDXRFS), portable X-ray fluorescence spectrometry (PXRFS), flame atomic absorption spectrometry (FAAS) and instrumental neutron activation analysis. In this work, the method of analysis, sensitivity, precision and accuracy performances of the related techniques were outlined.
104

Determinação de cobre, cromo e arsênio em madeira preservada (Eucalyptus sp.) pelas espectrometrias de fluorescências de raios X / Cu, Cr and As determination in preserved woods, Eucaliptus ssp, by x-ray fluorescence spectrometries

Sergio Matias Pereira Junior 08 December 2014 (has links)
O Brasil produz cerca de 2,2 milhões de metros cúbicos de madeira preservada para atender à demanda anual nos setores de transporte ferroviário, elétrico, rural e de construção civil. As espécies de madeiras mais usados são do eucalipto (Eucalyptus sp.) e pinus (Pinus sp.). A madeira preservada, utilizada para postes, dormentes, mourões e nas construções em madeira, deve estar em conformidade com as especificações exigidas pelas normas brasileiras quanto ao seu tratamento preservativo. No Brasil, os preservativos de madeira mais utilizados e regulamentados são CCA (arseniato de cobre cromatado) e o CCB (sal de cobre cromo e boro). As técnicas analíticas como espectrometria de absorção atómica de chama (FAAS) e espectrometria de emissão de plasma acoplado (ICPOES) e espectrometria de fluorescência de raios x (XRFS) são utilizadas para a avaliação desses processos. Neste trabalho, as amostras de madeira foram obtidas de árvores de eucalipto (Eucalyptus sp.), provenientes de áreas de plantação do estado de Minas Gerais, Brasil. Amostras de madeira de eucalipto foram submetidas a diferentes concentrações de solução de CCA, sob pressão, atingindo retenções de 3,9; 6,7; 9,1; 12,4 e 14,0 kg de CCA por m-³ de alburno. A partir dos blocos tratados foram obtidos amostras em forma de cilindros e serragem. A determinação de cobre, cromo e arsênio foi realizada pela espectrometria de fluorescência de raios X de energia dispersiva (EDXRF), espectrometria de fluorescência de raios X portátil (PXRF), FAAS e IAAN. Neste trabalho, foram avaliados métodos de análise, sensibilidade e precisão, exatidão das técnicas analíticas relacionadas. / Brazil produces around 2.2 millions of cubic meters of treated wood to meet the annual demand of railway, electric, rural and construction sectors. The most used wood species are eucalyptus (Eucalyptus ssp.) and pine (Pinus ssp.).The treated woods used for poles, sleepers, fence posts and plywoods should be according to Brazilian norms requirements. The most usual wood preservative products used in Brazil are CCA (chromated copper arsenate) and CCB (copper chromium and boron salt). The analytical methods, such as flame atomic absorption spectrometry (FAAS), plasma inductively coupled optical emission spectrometry (ICPOES) and X-ray fluorescence spectrometry (XRFS) have been used for the analytical control of those treatment processes. In this work, the eucalyptus trees (Eucalyptus ssp) samples was obtained from Minas Gerais State, Brazil, cut plantation areas. Under pressure, eucalyptus wood samples were submitted to different concentration of CCA solution reaching 3.9, 6.7, 9.1, 12.4 and 14.0 kg of CCA by m-³ sapwood retentions. Samples in cylinders and sawdust forms were obtained from treated wood samples. Copper, chromium and arsenic determination was performed using the energy dispersive X-ray fluorescence spectrometry (EDXRFS), portable X-ray fluorescence spectrometry (PXRFS), flame atomic absorption spectrometry (FAAS) and instrumental neutron activation analysis. In this work, the method of analysis, sensitivity, precision and accuracy performances of the related techniques were outlined.
105

The potential of polyhalite as a multi-nutrient fertilizer for sugarcane / Potencial da polihalita como fertilizante multi-nutriente para cana-de-açúcar

Bejarano Herrera, Wilfrand Ferney 20 February 2019 (has links)
Sugarcane is one of the crops with the highest extraction of macronutrients from the soil, both in cane-plant and ratoon crops, being critical its reposition by means of fertilizers. In the Brazilian sugarcane agrosystem, the supply of elements, such as, potassium (K), calcium (Ca), magnesium (Mg) and sulfur (S) is commonly performed by fertilizers, like potassium chloride, and soil amendments, such as, lime and phosphogypsum, producing high costs by sole application. In this context, the study aimed to determine the potential of polyhalite as a multi-nutrient source of K, Ca, Mg and S and its effects on yield and quality of sugarcane. In order to reach this objective, the study was divided into three stages: i) field evaluation in low K soil comparing doses of POLY with the combined application of KCl and GYP to evaluate yield, quality, soil chemical parameters, straw and stalk macronutrient content in two sugarcane varieties. ii) elemental, mineralogical and release characterization of the polyhalite (POLY) and potassium chloride (KCl) by the use of micro X-ray fluorescence spectrometry (µXRF) and X-ray diffraction spectrometry; and (iii) evaluation under glasshouse conditions to evaluate the residual effect of the application of POLY dosages contrasted to the application of KCl, GYP and kieserite (KIE) in the leaf macronutrients content, and biomass production in an Oxisol with a low level of K. Based on the field experiment, the application of calcium (Ca), magnesium (Mg), sulfur (S) and mainly potassium (K), irrespective the source applied, affected positively the yield in sugarcane. Related to the dosage, application of 105 kg K2O ha-1, which corresponds to farmer\'s recommended dosage, promoted the highest stalk yields for both varieties, CV7870 and RB867515. This dosage keeps the adequate nutritional status of sugarcane ratoon and enhance the K content in stalk, promoting the accumulation of sucrose in this plant organ. In relation to the soil parameters, for the variety RB867515, after cultivation, most of the nutrient concentration remained in soil were not significant compared to control, suggesting that as much fertilizer is applied this variety will uptake and export. In contrast, the variety CV7870 showed higher remained values for soil Ca, Mg and S in the treatments compared to the control after cultivation, indicating a residual effect, irrespective the treatment. Based on the laboratory results, KCl granule in the moisture low-K sandy Oxisol has rapidly promoted dissolution of nutrients and then released Cl- and K+, being susceptible for leaching, whereas POLY granule performed as a slow-release fertilizer due to its low solubility compared to KCl, enhancing residual effect over time. The results of the glasshouse showed that DM yield and nutrient uptake were more correlated to high K dosages applied (42 and 63 mg kg-1) and K sources containing Ca and S in the formulation (POLY, KCl+GYP+KIE and ½KCl ½POLY), for both cane-plant and ratoon. However, when these sources were provided at the lowest dosage (21 mg kg-1) it was observed superior agronomic efficiency for all added nutrients, indicating that a combination of KCl and POLY can be used more efficiently as K source for sugarcane. Taking together, both experiments, in the field and in the greenhouse, showed that polyhalite is suitable to supply K, Ca, Mg and S at the farmer\'s dosage recommendation. Furthermore, the blend of 50% polyhalite and 50% KCl could be adopted for farmers minimizing plant nutrient losses with a more balanced nutrition. / A cana-de-açúcar é uma das culturas com maior extração de macronutrientes do solo, tanto em cana-planta quanto em soca, sendo fundamental sua reposição por meio de fertilizantes. O fornecimento de elementos como potássio (K), cálcio (Ca), magnésio (Mg) e enxofre (S) para cana-de-açúcar é comumente realizado por fertilizantes, como o cloreto de potássio, e condicionadores do solo, como calcário e gesso agrícola, gerando altos custos por cada aplicação. Neste contexto, o estudo teve como objetivo determinar o potencial de polialita (POLY) como fonte multi-nutriente de K, Ca, Mg e S e seus efeitos na produtividade e qualidade da cana-de-açúcar. Para isso, o estudo foi dividido em três etapas: i) avaliação em campo usando solo com baixo nível de K comparando doses de POLY com a aplicação combinada de KCl e gesso agrícola (GYP) para avaliar rendimento, qualidade, parâmetros químicos do solo, teor de macronutrientes de palha e colmo em duas variedades de cana-de-açúcar, CV7870 e RB867515. ii) caracterização elementar, mineralógica e de liberação do polihalita (POLY) e cloreto de potássio (KCl) pelo uso de espectrometria de micro fluorescência de raios X (µXRF) e espectrometria de difração de raios-X; e (iii) avaliação em condições de casa de vegetação do efeito residual da aplicação de dosagens de POLY em contraste com a aplicação conjunta de KCl, GYP e kieserite (KIE) no teor de macronutrientes foliares, e produção de biomassa. Com base no experimento de campo, a aplicação de Ca, Mg, S e principalmente K, independentemente da fonte aplicada, afetou positivamente o rendimento em cana-de-açúcar. Em relação à dosagem, a aplicação de 105 kg K2O ha-1, que corresponde à dosagem recomendada, promoveu os maiores rendimentos de colmos para ambas as variedades, CV7870 e RB867515. Essa dosagem mantém o estado nutricional adequado da cana-soca e aumenta o teor de K no colmo, promovendo o acúmulo de sacarose na planta. Em relação aos parâmetros do solo, para a variedade RB867515, após o cultivo, a maior parte da concentração de nutrientes remanescente no solo não teve efeito significativo em relação ao controle, sugerindo que, quanto mais fertilizante for aplicado, essa variedade será capaz de absorver e exportar. Em contrapartida, a variedade CV7870 apresentou maiores valores remanescentes de Ca, Mg e S no solo em relação ao controle após o cultivo, indicando um efeito residual, independentemente do tratamento. Com base nos resultados laboratoriais, o grânulo de KCl em solo úmido com baixo teor de K promoveu rapidamente a dissolução dos nutrientes e liberou Cl- e K+, sendo mais suscetível à lixiviação, enquanto que o grânulo POLY apresentou baixa solubilidade em comparação ao KCl, aumentando o efeito residual ao longo do tempo. Os resultados mostraram que a produção de biomassa e a absorção de nutrientes foram mais correlacionados às altas doses K (42 e 63 mg kg-1) e fontes de K contendo Ca e S na formulação (POLY, KCl + GYP + KIE e ½KCl ½POLY), tanto para cana-planta quanto para soca. Entretanto, quando essas fontes foram fornecidas na dose mais baixa (21 mg kg-1), foi observada eficiência agronômica superior para todos os nutrientes adicionados, indicando que uma combinação de KCl e POLY seria mais eficiente como fonte de K para cana-de-açúcar. Numa avaliação geral, a polihalita foi adequada para fornecer K, Ca, Mg e S na dose recomendada de 105 kg K2O ha-1. Assim mesmo, a mistura de 50% de polihalita e 50% de KCl pode ser adotada para os agricultores reduzindo as perdas nutricionais para planta.
106

Papel dos elementos-traço em neoplasias mamárias: estudo através de técnicas espectroscópicas de fluorescência de raios X e análises imunohistoquímicas / Role of trace elements in breast cancer: Study by X-Ray Fluorescence spectroscopy techniques and Immunohistochemical analysis.

Silva, Marina Piacenti da 23 September 2011 (has links)
Neste trabalho foi avaliado o papel de elementos-traço em tecidos mamários neoplásicos e seu potencial como marcadores tumorais e fatores prognósticos. As concentrações dos elementos cálcio, ferro, cobre e zinco em tecidos normais e neoplásicos foram determinadas através de técnicas de fluorescência de raios X por dispersão por energia e por reflexão total. Modelos diagnósticos (análise de discriminante e curvas ROC - Receiver Operating Characteristic) baseados na análise estatística das distribuições de concentrações dos elementos mostraram que é possível classificar os diversos tipos de tecidos mamários (normais, benignos e malignos). Foi possível ainda avaliar a expressão dos elementos-traço e correlacioná-la com dados clinicopatológicos de importância prognóstica e com a sobrevida global de pacientes com câncer de mama. Os resultados mostraram que a expressão dos elementos-traço pode ser utilizada como marcador tumoral e fator prognóstico. Através da técnica de micro fluorescência de raios X, as distribuições espaciais dos elementos-traço foram avaliadas e comparadas com a expressão imunohistoquímica de metaloproteinases de matriz (MMPs), seus inibidores (TIMPs) e com o fator de crescimento vascular endotelial (VEGF). Os resultados mostraram que os elementos Fe, Cu e a expressão do VEGF estão correlacionados, sugerindo que o acúmulo destes elementos pode estar associado ao processo angiogênico em neoplasias mamárias. Foram observadas ainda correlações entre as distribuições de Ca, Zn e a expressão de MMPs e TIMPs, possivelmente devido à presença destes metais nestas proteínas. / In this work the role of trace elements in neoplastic breast tissues were evaluated to be applied as tumoral biomarkers and prognostic factors. Concentrations of trace elements like calcium, iron, copper, and zinc in normal and neoplastic tissues have been determinate by X-Ray Fluorescence (XRF) spectroscopic techniques. Diagnostic models (discriminant analysis and ROC curves) based on statistics analysis of trace elements concentrations distributions reveal that it is possible to classify different breast tissues (normal, benign and malignant). Also, it was possible to evaluate trace elements expression and correlate them with clinic-pathological data that are important in prognostic and the overall survival of breast cancer patients. The results presented have shown that trace elements expression can be used as tumoral biomarkers and prognostic factors. The spatial distributions of trace elements were evaluated by micro-XRF and the results were compared to immunohistochemical expression of matrix metalloproteinases (MMPs) and their inhibitors (TIMPs), as well as with vascular endothelial growth factor (VEGF). The results reveal that elements Fe, Cu and VEGF expression are correlated, indicating that the higher levels of these elements are associated with angiogenic process in breast cancer. Also, correlations between Ca, Zn and MMPs and TIMPs expression have been observed, possibly due those metals are present in these proteins.
107

Avaliação da concentração de elementos traço e respectivos mapas de distribuição em placenta bovina / Determination of trace elements and their distribution maps in bovine placenta

Will, Sonia Elisabete Alves de Lima 15 December 2010 (has links)
O desenvolvimento sadio e harmonioso de uma gestação está relacionado diretamente a nutrição fetal equilibrada. Alguns minerais são essenciais por meio das funções desempenhadas no metabolismo, manutenção e crescimento fetal. As carências minerais estão entre os fatores que mais contribuem para a baixa produtividade de rebanho, gerando perdas econômicas significativas. Desse modo estudos que auxiliam na compreensão das razões para a baixa produtividade em rebanhos são importantes. A placenta atua como uma barreira seletiva ao fornecimento adequado de nutrientes durante a gestação. O principal objetivo deste estudo foi determinar a concentração de elementos traço para animais não manipulados (GCO) e clonados (GCL) para períodos gestacionais e obter mapas de distribuição qualitativos para placenta de bovinos GCO e GCL. As amostras de tecido placentário foram selecionadas e agrupadas em três períodos gestacionais: estágio 1, 90 dias; estágio 2, 135 dias e estágio 3, 235 dias. Todas as amostras foram analisadas para os elementos constituintes e traço por Espectrometria de Raios X. Os resultados obtidos nas análises de tecido placentário contendo elementos constituintes e traço indicaram que os procedimentos de preparação foram adequados. Os resultados obtidos indicaram variações significativas para os elementos Na, Mg, P, Cl, K e Ca. Os mapas de distribuição elementar confirmaram que a maior concentração elementar ocorreu na região de interdigitação entre as criptas carunculares do epitélio uterino e as vilosidades cotiledonária com células trofoblásticas na região dos placentônios e nas glândulas endometriais da região interplacentomal, indicando que nestas regiões intensificam-se as trocas de nutrientes entre mãe e feto. Para os resultados obtidos na avaliação dainterelação elementar, quanto as amostras de placentônio bovino clonado observou-se as interelações entre Ca-Fe, Cu-Fe, Zn-Ca, Fe-Zn, Ca-Cu e Cu-Zn. Pelo exposto acima, concluiu-se que as análises químicas foram adequadas para a determinação da concentração de elementos constituintes e traço e que a análise qualitativa dos mapas bidimensionais e mapas de correlação obtidos por meio de experimento com radiação Síncrotron foram essenciais para a discussão sobre as alterações nas regiões selecionadas e períodos de gestação avaliados. / The healthy and harmonious development of a gestation is directly associated to a balanced fetus nutrition. Some minerals are essential because of their functions developed in the metabolism, maintenance and fetus development. Mineral deficiencies are among the factors that contribute the most for a low productivity of the cattle, generating significant economic loss. Thus, studies that help understand the reasons for a low productivity in cattle are important. The placenta works as a selective barrier to the adequate supply of nutrients during the gestation. The aim of this study was to determine the concentration of trace elements for non-manipulative animals (GCO) and cloned animals (GCL) for gestational periods and to obtain maps of qualitative distribution for the placenta of bovines GCO and GCL. Samples of placenta tissues were selected and grouped in three gestational periods: stage 1, 90 days; stage 2, 135 days; and stage 3, 235 days. All the samples were analyzed for the constituent elements and traces by X Rays Spectrometry. The results obtained in the analyses of placenta tissue bearing constituent elements and trace indicated that the procedures of preparation were adequate. The results indicated significant variations for the elements Na, Mg, P, Cl, K e Ca. The maps of elementary distribution confirmed that the highest elementary concentration occurred in the region of inter-digitation of carunculate vaults of the uterine epithelium and cotiledonary vilosities with trophoblast cells, in the regions of the placentons and endometrial glands of the interplacentomal region, confirming that, in these regions, nutrient exchanges intensify between mother and fetus. For the results obtained in evaluation of the elementary interrelation in relation to the samples of cloned bovine placentons we observed that the maps demonstrated several interrelations between Ca-Fe, Cu-Fe, Zn-Ca, Fe-Zn, Ca-Cu, and Cu-Zn. By these results, we concluded that the chemical analyses were adequate for the determination of the elementary concentration of constituent elements and trace and also that the qualitative analysis of the bi-dimensional maps and correlated maps obtained through experiments with Synchrotron radiation were essential for the discussion on alterations on selected regions and on evaluated periods of gestations.
108

Arqueologia guarani no litoral central de Santa Catarina / Guarani Archaeology in the Central Coast of Santa Catarina

Müller, Isabela da Silva 13 May 2019 (has links)
A dissertação propõe a construção de uma história indígena guarani de longa duração no litoral central catarinense a partir de uma Arqueologia do Lugar Guarani. Para isso, são analisadas duas coleções cerâmicas provenientes da ilha de Santa Catarina (Florianópolis): a coleção Travessão do Rio Vermelho (TRV) (escavada entre os anos de 2013 e 2014 pela equipe do Laboratório de Estudos Interdisciplinares em Arqueologia - LEIA/UFSC) e a coleção Lagoinha do Rio Tavares I (RT) (escavada nos anos 1965 e 1966, portanto, durante o PRONAPA, pelo Professor Doutor Walter Fernando Piazza). Essas coleções são analisadas conjugando a análise tecnológica e a arqueometria (por fluorescência de raios-x), ressaltando a importância da coordenação de diferentes métodos e da interdisciplinaridade na Arqueologia. A discussão e o objetivo são alcançados a partir das análises das coleções e dos lugares (sítios arqueológicos) e da interseção entre Arqueologia, História, Etnologia e Etnohistória. Nesse sentido, é verificado que as análises tecnológica e de fluorescência de raios-x se demonstraram complementares para a discussão dos processos de produção das vasilhas (tendo na composição da pasta o eixo elementar para essa interpretação) bem como possíveis usos das vasilhas. Foi possível tratar de escalas de produção, de um locus de manipulação de alimento da vida coletiva no teko\'á e de um outro locus na periferia da aldeia relacionado à morte na cultura guarani. Ao buscar as particularidades dentro da estrutura presente na cerâmica guarani, foi evidenciada uma clara diferenciação entre as coleções em termos micro (material arqueológico em si) e macro (o material arqueológico e o lugar, o sítio arqueológico). / The mastering thesis proposes the raising of a Guarani indigenous history in a long duration to the central coast of Santa Catarina from a Guarani Archaeology of Place. For this, they are analyzed two ceramic collections from Santa Catarina Island (Florianópolis): the Travessão do Rio Vermelho (TRV) collection (excavated between 2013 and 2014 by Laboratório de Estudos Interdisciplinares em Arqueologia - LEIA/UFSC) and Lagoinha do Rio Tavares I (RT) collection (this one excavated between 1965 and 1966 by PhD Walter Fernando Piazza during PRONAPA). These collections are analyzed coordinating a technology and an archaeometry (x-ray fluorescence) perspectives, so that it was possible to emphasize the importance of coordinating different methods and the interdisciplinary in archaeology. The discussion and the objective are reached by collections\' and place\'s (archaeological sites\') analysis and by the intersection among archaeology, history, ethnology and ethnohistory. Then, it is verified that the technological and the x-ray fluoresce analysis were complementary to the discussion on ceramic\'s production processes (as paste\'s composition was elementary on this comprehension) as well as on possible vessel\'s uses. It was possible to reach production scales, to argue about a locus of food manipulation inside the collective life in the teko\'á and to argue about a locus related to the limits of the community associated to death on Guarani culture. Going through the particularities inside Guarani ceramic\'s structure, it was emphasized a clear defference between the analysed colections in micro (the archaeological material itself) and macro terms (the archaeological material and the place, the archaeological site).
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Modeling Study of Proposed Field Calibration Source Using K-40 Source and High-Z Targets for Sodium Iodide Detector

Rogers, Jeremy 1987- 14 March 2013 (has links)
The Department of Energy (DOE) has ruled that all sealed radioactive sources, even those considered exempt under Nuclear Regulatory Commission regulations, are subject to radioactive material controls. However, sources based on the primordial isotope potassium-40 (40K) are not subject to these restrictions. Potassium-40’s beta spectrum and 1460.8 keV gamma ray can be used to induce K-shell fluorescence x rays in high-Z metals between 60 and 80 keV. A gamma ray calibration source is thus proposed that uses potassium chloride salt and a high-Z metal to create a two-point calibration for a sodium iodide field gamma spectroscopy instrument. The calibration source was designed in collaboration with Sandia National Laboratory using the Monte Carlo N-Particle eXtended (MCNPX) transport code. The x ray production was maximized while attempting to preserve the detector system’s sensitivity to external sources by minimizing the count rate and shielding effect of the calibration source. Since the source is intended to be semi-permanently fixed to the detector, the weight of the calibration source was also a design factor. Two methods of x-ray production were explored. First, a thin high-Z layer (HZL) was interposed between the detector and the potassium chloride-urethane source matrix. Second, bismuth metal powder was homogeneously mixed with a urethane binding agent to form a potassium chloride-bismuth matrix (KBM). The two methods were directly compared using a series of simulations, including their x ray peak strengths, pulse-height spectral characteristics, and response to a simulated background environment. The bismuth-based source was selected as the development model because it is cheap, nontoxic, and outperforms the high-Z layer method in simulation. The overall performance for the bismuth-based source was significantly improved by splitting the calibration source longitudinally into two halves and placing them on either side of the detector. The performance was improved further by removing the binding agent and simulating a homogeneous mixture of potassium chloride and bismuth powder in a 0.1 cm plastic casing. The split plastic-encased potassium chloride-bismuth matrix would serve as a light, cheap, field calibration source that is not subject to DOE restrictions.
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Die Entdeckung der Röntgenfluoreszenzanalyse / The discovery of x-ray fluorecence analysis

Niese, Siegfried 09 August 2012 (has links) (PDF)
Es wird die Entwicklung der Röntgenspektralanalyse und die Entdeckung der Röntgenfluoreszenzanalyse durch Georg von Hevesy und Richard Glocker mit ihren Assistenten in Freiburg i. Br. und in Stuttgart 1928 beschrieben. / The development of the x-ray chemical analysis and the discovery of the x-ray fluorescence analysis by Georg de Hevesy and Richard Glocker with their assistants in Freiburg i. Br. and in Stuttgard 1928 is described.

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