Thesis (Ph. D.)--Florida State University, 2005. / Advisor: Dr. John G. Dorsey, Florida State University, College of Arts and Sciences, Dept. of Chemistry and Biochemistry. Title and description from dissertation home page (June 15, 2005). Document formatted into pages; contains xiv, 112 pages. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1968. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (MSc. (Pharmacology, Faculty of Health Sciences))-University of Pretoria, 2003. / Also available in print format.

Made available in DSpace on 2014-10-09T12:34:32Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:20Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Submitted in partial fulfillment of the requirements for the degree of Masters in Technology in Chemistry, M.L. Sultan Technikon, 2000. / Mycotoxins are a group of natural poisons produced by certain strains of fungal species when they grow under favourable conditions on a wide variety of different substrates. These toxins have been implicated in a wide range of acute diseases in man and animals. Their toxic effects include oesophageal cancer and liver diseases in humans, and carcinogenic effects in experimental rats and poultry. Hence, there is a need to monitor toxin levels in food commodities. / M

Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós-Graduação em Engenharia e Ciência de Alimentos, Escola que Química e Alimentos, 2010. / Submitted by Caroline Silva (krol_bilhar@hotmail.com) on 2012-08-13T20:09:02Z No. of bitstreams: 1 karen.pdf: 1201665 bytes, checksum: 029db9988527cfe9b943b9a5f0b24c2f (MD5) / Approved for entry into archive by Bruna Vieira(bruninha_vieira@ibest.com.br) on 2012-12-06T04:50:59Z (GMT) No. of bitstreams: 1 karen.pdf: 1201665 bytes, checksum: 029db9988527cfe9b943b9a5f0b24c2f (MD5) / Made available in DSpace on 2012-12-06T04:50:59Z (GMT). No. of bitstreams: 1 karen.pdf: 1201665 bytes, checksum: 029db9988527cfe9b943b9a5f0b24c2f (MD5) Previous issue date: 2010 / O tomate (Lycopersicon esculentum Mill) constitui um alimento rico em vitaminas dos complexos A e B e minerais importantes, além de ácido fólico, cálcio e frutose. Ainda o tomate contém licopeno, que é um poderoso antioxidante, capaz de neutralizar a ação dos radicais livres, responsáveis pelo envelhecimento e degeneração das células Poucos produtos in natura têm um conteúdo de umidade tão alto quanto o tomate (cerca de 95%, b.u.) e a sua desidratação tem sido um desafio. A secagem é uma importante operação unitária na conservação de alimentos, pois tem a finalidade de reduzir a atividade de água e conseqüentemente a ação microbiana, reações enzimáticas, oxidativas e hidrolíticas do produto e aumentar sua vida útil. Este trabalho teve como objetivo principal analisar as condições operacionais da secagem de tomate em camada delgada, com escoamento paralelo do ar de secagem, avaliando as características do produto final. Os objetivos específicos foram caracterizar a secagem através de curvas características experimentais, determinar a constante de secagem, difusividade efetiva de umidade e energia de ativação e definir a condição mais adequada para a secagem em camada delgada de tomate utilizando a metodologia de superfície de resposta. As variáveis estudadas foram temperatura (60, 70 e 80°C) e espessura da fatia de tomate (3, 5 e 7mm), buscando como resposta o teor de licopeno, cor, através do ângulo de Hue, e capacidade de produção. Os resultados mostraram que a secagem de tomate em camada delgada, com escoamento paralelo do ar, apresentou o período de taxa constante e primeiro e segundo períodos de taxa decrescente. A difusividade efetiva ficou entre 1,56.10-10 e 2,67.10-10 m²/s para o primeiro período de taxa decrescente e entre 4,21.10-11 e 8,35.10-11 m²/s para o segundo período de taxa decrescente. A energia de ativação apresentou valores médios de 16,99 e 30,64 kJ.mol-1 para o primeiro e segundo período de taxa decrescente, respectivamente. A condição mais adequada de operação encontrada foi temperatura do ar de secagem de 60°C e espessura da fatia de tomate de 3 mm, onde apresentou cor de 47,70°, teor de licopeno de 301,69 μg/g e capacidade de produção de 1,65 kg/m²h. / Tomato (Lycopersicon esculentum Mill) is a product rich in vitamins from complex A and B, and important minerals, besides folic acid, calcium and fructose. Tomato has also lycopene, that is a powerful antioxidant, able to neutralize radicals action, which causes the cell’s aging and degeneracy. Few in natura products have moisture content as high as tomato (about 95%, w.b.) and its dehydration has been a challenge. Drying is an important unit operation for food conservation, because its aim is to reduce the water activity and therefore the microbian action, enzymatic reactions, oxidative and hydrolytic of the product and raise its expiration date. The main purpose of the present work is analyze the operational conditions of tomato thin layer drying, using parallel flow of drying air, evaluating the final product characteristics. The specific purposes were to characterize drying through characteristics experimental curves, to determine the drying constant, moisture effective diffusivity and activation energy and also define the more suitable condition to dry tomato in thin layer based on surface response methodology. The studied variables were temperature (60, 70 and 80°C) and tomato thickness (3, 5 and 7mm), searching as responses the lycopene percentage, color though the Hue’s angle, and manufacture capacity. The results showed that tomato’s thin layer drying, using a parallel flow, reveals the constant rate period and the first and second periods of decreasing rates. The effective diffusivity was between 1,56.10-10 and 2,67.10-10 m²/s for the second period of decreasing rate. The activation energy has shown average values of 16,99 and 30,64 kJ.mol-1 for the first and second periods of decreasing rates, respectively. The best operational condition found was 60°C of drying temperature and 3 mm of tomato thickness, where reveals 47,70° of color, 301,69 μg/g of lycopene percentage and manufacturing capacity of 1,65 kg/m²h.

Made available in DSpace on 2014-10-09T12:34:32Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:20Z (GMT). No. of bitstreams: 0 / As espécies da família Zingiberaceae são caracterizadas por suas raízes. Constituintes fenóis como curcuminóides e gingeróis destacam-se por suas atividades biológicas. A irradiação de alimentos é um meio de preservação eficiente, porém, é importante garantir que suas propriedades funcionais sejam preservadas. Este trabalho vem avaliar o efeito do processamento por radiação gama de 60Co em doses de 0, 5, 10, 15 e 20kGy sobre espécies de Zingiberaceae: açafrão (Curcuma longa L.), gengibre (Zingiber officinale Roscoe) e zedoária (Curcuma zedoaria (Christm.) Roscoe). A determinação qualitativa do perfil de compostos bioativos foi realizada por cromatografia de camada delgada. A quantificação de compostos fenólicos foi realizada pelo método Folin-Ciocalteu e a avaliação do potencial da atividade antioxidante pelo teste de captação do radical livre [2,2 difenil-1-pricril-hidrazil (DPPH)] e método Rancimat®. A quantificação de curcumina e 6-gingerol foram realizadas por Cromatografia Líquida de Alta Eficiência. Não houve mudança no perfil fitoquímico das espécies após o tratamento por irradiação. Em relação às amostras controle, houve perdas significativas no teor de compostos fenólicos nas amostras de açafrão nas doses de 15kGy e 20kGy. Ocorreu decréscimo significativo da capacidade de captação do DPPH nos extratos de gengibre irradiados e no extrato de zedoária irradiado com 20kGy. O Índice de Atividade Antioxidante foi significativamente menor nos extratos de açafrão irradiados com 5kGy e 15kGy e nos extratos irradiados de zedoária. A quantificação de curcumina foi significativamente menor nos extratos de açafrão irradiados com 15 kGy e não houve diferença significativa na quantificação de 6-gingerol entre os extratos de gengibre. Conclui-se que a tecnologia de processamento de Zingiberaceae por radiação gama pode ser viável para as indústrias. Para segurança da manutenção da atividade antioxidante as doses devem ser de até 10kGy. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

La nano-structuration des surfaces est un intrigant domaine de la physique des matériaux que l’homme s’est approprié aussi bien à des fins esthétiques que fonctionnelles. Les nanostructures peuvent être présentes à l’état naturel (effet déperlant de la feuille de lotus) ou à l’état artificiel pour répondre à des besoins techniques et peuvent alors être fabriquées par lithographie. Le procédé étudié dans cette thèse est la nanoimpression thermique qui permet de répliquer à moindre coût les micro- et nanostructures d’un moule vers la surface d’un substrat. Ce procédé d’embossage consiste à imprimer le moule dans un film mince de polymère thermoplastique (50 à 500 nm d’épaisseur) préalablement déposé sur le substrat. Eventuellement, une étape ultérieure de gravure permet de transférer dans ce dernier les motifs imprimés. On s’intéresse en particulier à l’évaluation des vitesses d’impression des structures dans des films de polystyrène sur substrat de silicium. Un logiciel de simulation numérique a été développé ; il utilise la méthode des éléments naturels contraints (C-NEM). L’accent a été mis sur la prise en compte de trois effets éminemment importants à l’échelle nanométrique : tension de surface, mouillage, glissement à l’interface fluide-solide. Combiné à un comportement visqueux non linéaire, cela permet de rendre partiellement compte des phénomènes physiques qui surviennent lors de l’impression et d’avoir des temps de simulation compatibles avec les contraintes industrielles tout en conservant une évaluation pertinente des vitesses d’impression. Cette démarche nous place à mi-chemin entre des modèles analytiques très simples mais ayant un cadre d’utilisation très restreint et des modèles plus complexes trop onéreux pour la simulation, comme la viscoélasticité en grandes transformations. Ces travaux abordent enfin le problème de la caractérisation du polymère à l’échelle des films minces. Un des défis majeurs relevés ici consistait à appliquer à des films minces le comportement du polymère caractérisé à l’échelle macroscopique. La validation expérimentale de toute la théorie élaborée a permis d’appuyer cette démarche et d’en révéler les limites. Ces approches théorique et expérimentale sont un premier pas vers la conception d’un outil numérique d’optimisation de la nanoimpression thermique. / Surface nanostructuring is an intriguing field of materials physics that has been largely ado-pted for both aesthetic and functional purposes. Nanostructures can be present in nature (water repellent effect of the lotus leaf) or produced for industrial applications, and they can be manufactured by lithography. Thermal nanoimprint is the process studied in this thesis, which is an inexpensive method to replicate the micro- and nanostructures of a mold into the surface of a substrate. This embossing method consists in printing the mold into a thin film of thermoplastic polymer (50 to 500 nm in thickness) previously deposited on the substrate. A further etching step may transfer the imprinted patterns into the latter. The aim of this work is to evaluate the imprint speeds of the structures in thin polystyrene films on a silicon substrate. A numerical simulation software has been developed, which uses the Constrained Natural Elements Method (C-NEM). Our main contribution was to integrate three essential phenomena at the nanoscale: surface tension, wetting, and slip at the fluid-solid interface. Combined with a non-linear viscous behavior, this is shown to describe partially but sufficiently the physical phenomena that occur during printing. Therefore, this work lies halfway between simple analytical models, with a very limited scope of use, and complex models too expensive for simulation, such as finite strain viscoelasticity. Finally, this thesis addresses the problem of the characterization of a polymer in thin films. One of the major challenges faced here was to apply the macroscopic mechanical behavior to thin films. The experimental validation of the theory developed in the first part has corroborated this approach and revealed its limitations. This set of theoretical and experimental developments is a first step towards the design of a numerical tool for optimizing the thermal nanoimprint process

Coastal areas around the world have been recognized as largely impacted by anthropogenic activities resulting in pollution of marine sediments. In Sweden, surveys conducted along the coastline of the Bothnian Bay have identified a total area of about 29 km2 as fiber rich sediments. In the Bureå sea area near Skellefteå vicinity, Västerbotten county, elevated levels of mercury (Hg), methyl-Hg, arsenic (As), copper (Cu), lead (Pb), cadmium (Cd), zinc (Zn) and polycyclic aromatic hydrocarbons (PAH) have been classified and believed to be mainly affected by emissions from a pulp and paper industry formerly active on a nearby headland.  Contaminants in sediments are of concern as continuous dispersion can adversely affect the benthic community. To isolate contaminants and reduce their bioavailability, in-situ thin-layer capping using an active material is one suitable approach. This type of remediation method, using biochar mixed with bentonite clay will be implemented on a pilot scale in the sea area outside of Bureå in the spring of 2021. However, bentonite is a relatively expensive material yielding a need to further develop the selection of capping materials suitable to aid in the deposition of biochar in an active thin-layer cap. In this thesis, biochar-based thin layer caps mixed with bentonite clay, rock dust of two grain sizes and a concrete-based slurry was evaluated on their physicochemical properties and efficiency for preventing release of trace elements from sediment to the overlying water. This was conducted by a laboratory column experiment where four set ups were performed: (1) no capping for sediment control, (2) only capping material for material control, (3) sediment mixed with biochar and (4) sediment capped with each material mixed with biochar. Three times during an 8-week test period, 60 mL of the overlying water in the columns was extracted and sent for trace element analysis.  The experimental set up revealed that the capping layers effectively prevent release of trace elements trough the sediment to the overlying water. The concrete slurry showed suitable settling properties and negligible loss of biochar in the set-up of the columns. Also, the biochar+concrete slurry thin-layer cap displayed the highest efficiency for preventing and/or delaying release of As, P, Cu, Fe, Mn and SO4.

Recent work in this laboratory has centered around Platinum metals and their coordination compounds. Specifically, Thin-Layer Chromatography of Platinum metal ions has been reported in one of the recent dissertations (1). The purpose of the present work was to carry out a systematic study of Thin-Layer Chromatography on the following complexes: Tetrammine Platinum (II) Chloride [Pt (NH3)4]Cl2 Tetraammine Palladium (II) Chloride. [Pd (NH3)4]Cl2 Hexammine Platinum (IV) Chloride. [Pt (NH3)6]Cl4 Hexammine Palladium (IV) Chloride [Pd (NH3)6]Cl4 After the complexes had been synthesized, the main problem lay in finding a suitable adsorbent and solvent system for separating a mixture of all four complexes as well as an appropriate locating reagent, so that once the separation had been accomplished, complexes could be identified.