Thesis (Ph.D.)--University of Nebraska-Lincoln, 2006. / Title from title screen (site viewed on Nov. 10, 2006). PDF text: xii, 363 p. : ill. ; 5.26Mb. UMI publication number: AAT 3214725. Includes bibliographical references. Also available in microfilm and microfiche format.

This diploma thesis deals with the use of fluorescent probes for evaluation of photocatalytic activity of immobilized photocatalyst. To the evaluation of photocatalytic activity of TiO2 were used three different fluorescent probes – terephthalic acid, coumarin and benzoic acid, wherein was monitored the increasing intensity of fluorescence of their oxidation products – hydroxyterephthalic acid, 7-hydroxycoumarin and salicylic acid for the photochemical degradation of various fluorescent probes. To the evaluation of photocatalytic activity was used solid phase (photocatalyst) – liquid phase (probe) system and was used three sources of radiation. Fluorescence of oxidation products was monitored by the fiber spectrometer and a conventional cuvette fluorometer.

Objetivos: Recentemente, a Espectroscopia de Fluorescência (EF) tem sido estudada como método de análise de propriedades da pele de forma nãoinvasiva e em tempo real, utilizada em uma variedade de aplicações, incluindo avaliação e diagnóstico do tecido in vivo. Contudo, na cicatrização da pele, essa técnica não tem sido completamente explorada. Visto que a determinação da idade de uma lesão é um aspecto importante na medicina forense, esse trabalho tem por objetivo testar a aplicabilidade da medida da Intensidade de Fluorescência (IF) após o uso de metil-aminolevulinato (MAL) na estimativa da idade de lesão incisa, através da EF ao longo do tempo e fazer a correlação desta com os achados histológicos. Materiais e Métodos: Foram utilizados camundongos hairless como modelo experimental. Os animais foram divididos em dois grupos: com (+) e sem (-) o uso de MAL antes da EF. Incisões cirúrgicas lineares foram realizadas no dorso de cada animal. Espectros na faixa de 480 e 800 nm foram coletados da lesão e da pele normal adjacente, usando o sistema Ocean Optics, correspondendo a quatro condições: a) IF da lesão após MAL (+/+); b) IF da pele normal após MAL (-/+); c) IF da lesão sem MAL (+/-) e d) IF da pele normal sem MAL (-/-). Após a cirurgia, os animais foram monitorados periodicamente até 3 meses de pós-operatório e eutanaziados em grupos. Fragmentos de pele, contendo todo o ferimento, foram removidos e processados para análise histológica por métodos estereológicos. Vários cortes histológicos foram analisados para avaliar a organização da derme e da epiderme, deposição de colágeno e proliferação celular (imunoistoquímica por PCNA). Resultados: Nas fases iniciais da cicatrização, a EF in vivo mostrou acúmulo preferencial de protoporfirinas na lesão com uso de MAL (+/+), quando comparado à pele normal adjacente (-/+). Contudo, nas fases avançadas, ocorreu o inverso. Houve uma diferença estatisticamente significante neste grupo (+/+) ao longo do tempo (p < 0,0001), o que não aconteceu com os demais ((-/+); (+/-) e (-/-)). O modelo apresentado permitiu a estimativa da idade de lesão incisa no intervalo de dois meses, sendo possível estimar a fase de cicatrização em que esta se encontra. Achados histológicos confirmaram as fases da cicatrização, mostrando correlação com os achados de fluorescência. Conclusão: Os resultados mostraram que a técnica de EF usando MAL é um método promissor na análise dos estágios da cicatrização da pele / Background and Objective: In recent years, Fluorescence Spectroscopy (FS) has been explored as a novel noninvasive and real-time technique for analysis of skin properties, useful in a wide variety of applications, including tissue evaluation and diagnosis. However, the use of FS in skin wound healing has not been fully explored. Since aging of injuries on a victims body is an important aspect of forensic medicine, this paper intended to test the usefulness of collecting Fluorescence Intensity (FI) after topical MAL on age estimate of the incised lesion, through the study by FS over time and correlation with histological findings. Materials and Methods: As experimental model, was used hairless mice. The mice were divided into two groups: with (+) and without (-) use MAL before FS. Standardized linear wounds were made on the dorsum of each mice. Spectra in the 480-800 nm wavelength range were collected from normal and wound skin using Ocean Optics system, corresponding to four conditions: a) FI of skin wound after MAL (+/+); b) FI of normal skin after MAL (- /+); c) FI of skin wound without MAL (+/-) and d) FI of normal skin without MAL (- /-). After wounding, the animals were monitored periodically until 3 months and killed in groups. Tissue specimens, containing the whole wound, were removed and processed for histological analysis using stereological techniques. Several cross-sections were analyzed to evaluate the organization of the dermis and epidermis, collagen deposition and cellular proliferation (PCNA - imunohistochemistry antigen). Results: In vivo FS of skin wound healing with MAL (+/+) showed that there was a protoporphyrin preferential accumulation in healing site as compared to adjacent normal skin (+/-) in the early stage of healing. However, in the later stages, the reverse happened. There was statistically significant into this group (+/+) along the time (p < 0,0001); what not happened with another groups ((-/+); (+/-) and (-/-)). The model allows to estimate the age of an incised injury into interval of two months. Its possible to estimating his healing phase. Histological findings confirm the stages of healing and agree well with the fluorescence findings. Conclusion: The results showed that FS using MAL appears to be a promising approach for the analysis of stages of skin wound healing

Drug delivery methods for the treatment of brain tumor cells have been both inefficient and potentially dangerous for cancer patients. Drug delivery must be done in a controlled manner so that the effective amount of medication is delivered to the patient and ensure over-dosage does not cause adverse side reactions in the patient. The focus of this investigation is to design a drug delivery system that would allow for site-specific administration of the drug, protection of the drug from the surrounding environment, and controlled sustained release of the drug. We have proposed a model that incorporates a niosome, which is a non-ionic surfactant vesicle, within a biodegradable polymer hydrogel. The drug is encapsulated in the niosome, and the niosome is embedded within a three-dimensional hydrogel network. It is therefore critical that the release rate of the drug from the niosome be studied. This investigation provides information about the release rate and behavior of the drug within the niosome as it is placed in a semi-permeable membrane. The niosome and dye solution in the cellulose membrane are placed in contact with water or PBS. Intensity measurements are taken using fluorescence spectrometry, and the readings are converted to concentration and moles values. The release rates of the dye from of the niosome and across the membrane are studied as the concentration data is collected over time. The results indicate that most of the niosomes will release their dye within ten hours. The water will create instability in the niosomes, while the PBS solution will maintain the stability of the niosomes. The concentration that diffuses across the cellulose membrane will steadily increase and can be predicted well by a simple diffusion model. We hope to use the information provided in this study to continue to design a drug delivery method that will stabilize the niosomes and allow for the maximum control over the release rate of the drug.

Objetivos: Recentemente, a Espectroscopia de Fluorescência (EF) tem sido estudada como método de análise de propriedades da pele de forma nãoinvasiva e em tempo real, utilizada em uma variedade de aplicações, incluindo avaliação e diagnóstico do tecido in vivo. Contudo, na cicatrização da pele, essa técnica não tem sido completamente explorada. Visto que a determinação da idade de uma lesão é um aspecto importante na medicina forense, esse trabalho tem por objetivo testar a aplicabilidade da medida da Intensidade de Fluorescência (IF) após o uso de metil-aminolevulinato (MAL) na estimativa da idade de lesão incisa, através da EF ao longo do tempo e fazer a correlação desta com os achados histológicos. Materiais e Métodos: Foram utilizados camundongos hairless como modelo experimental. Os animais foram divididos em dois grupos: com (+) e sem (-) o uso de MAL antes da EF. Incisões cirúrgicas lineares foram realizadas no dorso de cada animal. Espectros na faixa de 480 e 800 nm foram coletados da lesão e da pele normal adjacente, usando o sistema Ocean Optics, correspondendo a quatro condições: a) IF da lesão após MAL (+/+); b) IF da pele normal após MAL (-/+); c) IF da lesão sem MAL (+/-) e d) IF da pele normal sem MAL (-/-). Após a cirurgia, os animais foram monitorados periodicamente até 3 meses de pós-operatório e eutanaziados em grupos. Fragmentos de pele, contendo todo o ferimento, foram removidos e processados para análise histológica por métodos estereológicos. Vários cortes histológicos foram analisados para avaliar a organização da derme e da epiderme, deposição de colágeno e proliferação celular (imunoistoquímica por PCNA). Resultados: Nas fases iniciais da cicatrização, a EF in vivo mostrou acúmulo preferencial de protoporfirinas na lesão com uso de MAL (+/+), quando comparado à pele normal adjacente (-/+). Contudo, nas fases avançadas, ocorreu o inverso. Houve uma diferença estatisticamente significante neste grupo (+/+) ao longo do tempo (p < 0,0001), o que não aconteceu com os demais ((-/+); (+/-) e (-/-)). O modelo apresentado permitiu a estimativa da idade de lesão incisa no intervalo de dois meses, sendo possível estimar a fase de cicatrização em que esta se encontra. Achados histológicos confirmaram as fases da cicatrização, mostrando correlação com os achados de fluorescência. Conclusão: Os resultados mostraram que a técnica de EF usando MAL é um método promissor na análise dos estágios da cicatrização da pele / Background and Objective: In recent years, Fluorescence Spectroscopy (FS) has been explored as a novel noninvasive and real-time technique for analysis of skin properties, useful in a wide variety of applications, including tissue evaluation and diagnosis. However, the use of FS in skin wound healing has not been fully explored. Since aging of injuries on a victims body is an important aspect of forensic medicine, this paper intended to test the usefulness of collecting Fluorescence Intensity (FI) after topical MAL on age estimate of the incised lesion, through the study by FS over time and correlation with histological findings. Materials and Methods: As experimental model, was used hairless mice. The mice were divided into two groups: with (+) and without (-) use MAL before FS. Standardized linear wounds were made on the dorsum of each mice. Spectra in the 480-800 nm wavelength range were collected from normal and wound skin using Ocean Optics system, corresponding to four conditions: a) FI of skin wound after MAL (+/+); b) FI of normal skin after MAL (- /+); c) FI of skin wound without MAL (+/-) and d) FI of normal skin without MAL (- /-). After wounding, the animals were monitored periodically until 3 months and killed in groups. Tissue specimens, containing the whole wound, were removed and processed for histological analysis using stereological techniques. Several cross-sections were analyzed to evaluate the organization of the dermis and epidermis, collagen deposition and cellular proliferation (PCNA - imunohistochemistry antigen). Results: In vivo FS of skin wound healing with MAL (+/+) showed that there was a protoporphyrin preferential accumulation in healing site as compared to adjacent normal skin (+/-) in the early stage of healing. However, in the later stages, the reverse happened. There was statistically significant into this group (+/+) along the time (p < 0,0001); what not happened with another groups ((-/+); (+/-) and (-/-)). The model allows to estimate the age of an incised injury into interval of two months. Its possible to estimating his healing phase. Histological findings confirm the stages of healing and agree well with the fluorescence findings. Conclusion: The results showed that FS using MAL appears to be a promising approach for the analysis of stages of skin wound healing

Orientador: Walkiria Hanada Viotto, Renato Atílio Jorge / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-16T17:26:07Z (GMT). No. of bitstreams: 1 Domingos_LigiaDozena_M.pdf: 594328 bytes, checksum: 6999b69049d3e5caa516544947d844db (MD5) Previous issue date: 2010 / Resumo: A luteína, a qual são atribuídas propriedades antioxidantes, está associada à diminuição e prevenção da degeneração macular relacionada à idade (DMRI), principal causa de cegueira irreversível em idosos. Como este carotenóide não é sintetizado pelo organismo humano, a sua adição em iogurte é mais uma opção de suplementação de luteína, além de poder atuar na prevenção de foto-oxidação. As condições de estocagem de iogurtes em supermercados pode levar às alterações no produto devido à presença de riboflavina (RBF), que sob estímulo da luz e presença de oxigênio, promove oxidação de vitaminas, carboidratos, lipídeos e proteínas levando à formação de off-flavors e perda de nutrientes. Como a RBF emite fluorescência, uma das maneiras de avaliar a ocorrência de foto-oxidação em produtos lácteos é a determinação fluorimétrica da RBF. Para tal, uma metodologia empregando titulação espectrofluorimétrica de RBF utilizando proteína ligante de riboflavina (RBPO) como titulante, para determinação de RBF em leite foi otimizado e validado para iogurte. As determinações de RBF foram realizadas em espectrofluorímetro com acessório para medidas em front-face, em um ângulo de 27°. A seletividade do método foi determinada pela adição de padrão de RBF no iogurte e em água. As curvas se apresentaram paralelas com inclinações de 1,001 ± 0,007 e 1,00 ± 0,03 para as titulações de RBF em água e em iogurte, e os limites de detecção e quantificação foram 0,0558 mg e 0,1691 mg respectivamente. A repetitividade, estimada pelo desvio padrão relativo, foi de 4,0 %. A exatidão foi de 99 ± 2 %, e os experimentos de robustez mostraram que o método é efetivo mesmo quando o produto foi analisado após 30 dias de estocagem, em iogurtes produzidos em dias diferentes, com diferentes massas de iogurte, com e sem adição de água. A influência da luz, embalagem e adição de luteína na estabilidade oxidativa do iogurte durante o tempo de estocagem foi estudada. Adicionou-se corante contendo o equivalente a 1,5 mg de luteína, e o produto final acondicionado em embalagens com diferentes barreiras ao O2, foi estocado a 5°C, na presença e ausência de luz durante 35 dias. As amostras foram analisadas nos dias 0, 7, 14, 21, 28 e 35, e os parâmetros avaliados foram os teores de carotenóides totais, riboflavina, oxigênio dissolvido na amostra e presente no espaço vazio (headspace). Houve degradação da riboflavina nos iogurtes sem luteína e expostos à luz. Os iogurtes com luteína apresentaram teor de riboflavina e luteína constantes durante o tempo de estocagem, independente do tipo de embalagem usado. Quando presente, a luteína exerceu um papel protetor, impedindo a degradação da riboflavina e aumentando a estabilidade oxidativa do iogurte / Abstract: Lutein, to which is attributed antioxidant properties, is associated with reduction and prevention of age-related macular degeneration (ARMD), the leading cause of irreversible blindness in the elderly. This carotenoid is not synthesized by the human body, and its addition in yogurt is another option for supplemental lutein and could act in preventing photo-oxidation. The conditions of storage of yogurt in supermarkets can lead to changes in the product due to the presence of riboflavin (RBF), which under the stimulus of light and the presence of oxygen, promotes oxidation of vitamins, carbohydrates, lipids and proteins, leading to the formation of off-flavors and loss of nutrients. Since RBF fluorescences, one of the ways to evaluate the occurrence of photo-oxidation in dairy products is the fluorimetric determination of the RBF. For this, a methodology for the determination of RBF in milk employing spectrofluorimetric titration using the protein (RBPO) as titrant was optimized and validated for yogurt. Measurements of RBF were performed using a spectrofluorimeter with accessory measures in front-face at an angle of 27°. The selectivity of the method was determined by standard addition of RBF in yogurt and in water. The curves performed in parallel with slopes of 1.001 ± 0.007 and 1.00 ± 0.03 RBF for titrations in water and in yoghurt and the detection limits and quantification were 0.0558 mg and 0.1691 mg, respectively. The repeatability, estimated by the relative standard deviation was 4.0%. The accuracy was 99 ± 2% and the experiments showed that method robustness is effective even when the product was tested after 30 days of storage for yogurts produced on different days with different masses of yogurt, with or without addition of water. The influence of light, packaging and addition of lutein to yogurt during storage time was studied. A dye containing the equivalent of 1.5 mg of lutein was added and the final product was packed in containers with different barriers to O2 stored at 5° C in the presence and absence of light. The samples were analyzed on days 0, 7, 14, 21, 28 and 35. The parameters evaluated were the levels of carotenoids and riboflavin, and of oxygen dissolved in the sample and present in the headspace. There was degradation of riboflavin in yogurt without lutein and exposed to light. The yogurts with lutein showed that riboflavin content and lutein contents were constant during the storage time, regardless of the packaging used. When present, lutein had a protective role, preventing the degradation of riboflavin and increasing the oxidative stability of yogurt / Mestrado / Mestre em Tecnologia de Alimentos

This thesis explores the findings of a diachronic analysis of three lithic assemblages from Quadra Island, British Columbia. From this, insights flow about the genealogies of technological practice and communities of skilled practitioners who inhabited the study area throughout its deep history. I use qualitative and quantitative methods including macroscopic lithic analysis, thin section petrography, X-ray fluorescence spectrometry, and morphometrics to operationalize these theoretical foundations. This suite of complementary methods and theory weaves a narrative of technological change alongside simultaneous continuity for hundreds of generations of human life. I argue this is evidence of the dynamic, sophisticated, yet enduring knowledge and practice of the inhabitants of the Discovery Islands throughout their deep histories that persist in the present. / Graduate / 2019-04-16

Water is the essential part of every organism and it is also a vital constituent of healthy living and diet. Unfortunately water contamination over the past decade has increased dramatically leading to various diseases. As technology advances, we are detecting many pollutants at smaller levels of concentrations. Arsenic (As) is one of those major pollutants, and Arsenic poisoning is a condition caused due to excess levels of arsenic in the body. The main basis for Arsenic poisoning is from ground water which naturally contains high concentrations of arsenic. A case study from 2007 states that over 137 million people in 70 countries were affected by arsenic poisoning from drinking water [1]. This thesis work is motivated by this study and investigates the fabrication, characterization, and testing of Opuntia ficus-indica mucilage nanofiber membranes formed using a mucilage, polystyrene (PS) and iron oxide (Fe2O3) solution by an electrospinning process. Cactus mucilage is a jelly-like substance, which is extracted from the cactus pad, and is an inexpensive, biodegradable and biocompatible material. It is also an abundant material available in nature. Polystyrene is a synthetic aromatic polymer prepared from monomer styrene. Polystyrene is further dissolved using D-Limonene as a solvent. D-Limonene is a non-toxic solvent and is a citrus extract of orange peelings. In an effort to enhance adsorption capacity for the mucilage nanofiber membranes, iron oxide nanopowder is incorporated into the polymeric solution. A mucilage and polystyrene-iron oxide solution is mixed in different ratios and electrospun to obtain nanofibers. The fibers will be characterized by certain techniques such as Scanning electron microscopy (SEM), contact angle measurements, viscosity and Fourier transform infrared spectroscopy (FTIR). The fibers obtained from mucilage and PS-Fe2O3 will be further tested under Atomic fluorescence spectrometry (AFS) for testing the removal of arsenic from water. Also, a life cycle analysis (LCA) is conducted to evaluate the environmental impacts of the fabrication of the membranes by using SimaPro® software.

Speciation analysis of arsenic based on selective hydride generation and detection by atomic fluorescence spectrometry have been studied in this work. It was found that under optimum conditions of atomization in the flame in gas shield atomizer, sensitivity was approximately twice higher and detection limit was about four times lower compared to miniature diffusion flame, which is a standard atomizer for atomic fluorescence spectrometry. The conditions to generate hydrides from both inorganic forms of the arsenic, i.e. from arsenite and arsenate, with the same efficiency have been found in the batch arrangement, by using 1 mol dm-3 hydrochlorid acid and 1% solution of tetrahydridoborate. To determine only trivalent form, TRIS buffer at pH 6.00 was used together with 1% sodium tetrahydridoborate. The detection limits found for inorganic arsenic, i.e. for arsenite and arsenate, respectively, were 15 ng dm-3 and 9 ng dm-3 . It was found that in the batch arrangement under these conditions it is possible to generate corresponding hydrides methylarsonate and dimethylarsonate with the same efficiency as from the inorganic form. Finally, it was found when slightly changing the gas-liquid separator design in order to introduce the mixture of tetrahydridoborate with hydrochloric acid to the bottom of the...

(EN) The presented dissertation is devoted to hydride generation from arsenic species and its application for speciation analysis based on atomic fluorescence detection. Hydride generation from toxicologically relevant arsenic species was optimized in order to achieve a 100% efficiency. The resulted experimental setup was subsequently used for speciation analysis of arsenic in human urine by high performance liquid chromatography with detection by atomic fluorescence spectrometry. The accuracy of the developed method was verified by comparative analyses of human urine samples collected from five individuals with an independent reference method. The cleavage of As-C bond during the reaction of methylated arsenic species with tetrahydridoborate(1-) (THB) in acidic media was studied in detail. Pronounced demethylation of methylated arsenic species was found during the reaction of THB with HCl, H2SO4, and HClO4 while hydride generation from CH3COOH or TRIS buffer after prereduction with L- cysteine resulted in the exclusive formation of the corresponding hydrides. Firstly, this phenomenon can endanger the accuracy of arsenic speciation which is based on hydride generation of substituted arsanes. Secondly, the more complex arsenic species can be converted to the hydride. That was demonstrated on hydride...