Rare earth RE3+ doped fluorophosphates glasses and glass ceramics are among the most promising candidates for high efficiency laser generation in the near-infrared spectral region. Glass ceramics are polycrystalline materials of fine microstructure that are produced by the controlled crystallization (devitrification) of a glass. By developing fluorophosphate base glasses with appropriate compositions and by controlling crystal nucleation and growth in them, glass ceramics with special properties can be fabricated combining the advantages of fluorides (low phonon energy, low refractive indexes, extensive optical window, lower hygroscopicity) and oxides (high chemical and mechanical stability and high dopant solubility), resulting in enhancement of the RE3+ emissive properties. In this study, we present the synthesis by melting/quenting and structural/spectroscopic investigation of new glasses and glass ceramics with composition 25BaF225SrF2(30-x)Al(PO3)3xAlF3(20-z)YF3: zREF3, where x = 15, 20 or 25, RE = Er3+ an/or Yb3+ and Nd3+. A detailed structural investigation of a series of this glasses has been conducted, using Raman, solid-state nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) spectroscopies. / Vidros e vitrocerâmicas fluorofosfatos dopados com íons terras raras (TR3+) estão entre os candidatos mais promissores para a geração de laser de alta eficiência na região espectral do infravermelho próximo. As vitrocerâmicas são materiais policristalinos com microestrutura bem definida obtida a partir da cristalização controlada do vidro base. Desenvolvendo vidros base de fluorofosfato com composições apropriadas e controlando a nucleação e crescimento de cristais, vitrocerâmicas com propriedades especiais podem ser fabricadas combinando as vantagens dos fluoretos (baixa energia de fônons, baixos índices de refração, janela ótica extensa, baixa higroscopicidade) e óxidos (alta estabilidade química e mecânica e alta solubilidade dopante), resultando no aumento das propriedades emissoras dos íons TR3+. Neste estudo, apresentamos a síntese por fusão/resfriamento e investigação estrutural/espectroscópica de novos vidros e vitrocerâmicas com composição 25BaF225SrF2(30-x)Al(PO3)3xAlF3(20-z)YF3: zREF3, onde x = 15, 20 ou 25, RE = Er3+ an / ou Yb3+ e Nd3+. Uma investigação estrutural detalhada de uma série destes vidros foi conduzida utilizando espectroscopias Raman, de ressonância magnética nuclear de estado sólido (RMN) e de ressonância paramagnética eletrônica (EPR).

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / O interesse pela eletrodeposiÃÃo de CuNi e suas mÃltiplas camadas à principalmente devido Ãs propriedades destes materiais, tais como: resistÃncia à corrosÃo, propriedades mecÃnicas (alta forÃa de traÃÃo, maleabilidade e ductilidade) e magnÃticas, alÃm de suas propriedades catalÃticas. Os resultados voltamÃtricos deste trabalho sugerem que a liga de CuNi à eletrodepositada formando uma soluÃÃo sÃlida. Por voltametria cÃclica, foi investigada a influÃncia de diferentes banhos complexantes na eletrodeposiÃÃo de CuNi, onde se observou a formaÃÃo de ligas mais nobres em banhos de sulfato e tartarato e ligas menos nobres em meio de citrato e citrato/tartarato. Foram realizados experimentos hidrodinÃmicos, onde severificou que CuNi em meio de sulfato e tartarato apresentam transporte de massa difusional. Para CuNi em meio de citrato e citrato/tartarato, nÃo foi observado a formaÃÃo de patamares difusionais, onde se sugere um transporte de massa por transferÃncia de carga ou misto. Pelos resultados obtidos observou-se que o meio complexante influÃncia na nobreza e no tipo de transporte de massa da liga formada. Por Energia Dispersiva de Raios-X, foi determinado o percentual atÃmico dos constituintes da liga, onde as ligas CuNi em banho de sulfato e tartarato apresentam um percentual de nÃquel em tono de 20% e em meio de citrato e citrato/tartarato, o percentual de nÃquel cai para 2% e 4%, respectivamente. Por espectrometria na regiÃo de absorÃÃo do UV-Vis, foram feitos curvas de calibraÃÃo e calculado _ para os metais individuais e para CuNi, sendo encontrado baixos valores, indicando que tanto os metais individuais como a liga nos diferentes meios complexantes apresentam transiÃÃes do tipo d-d. Foi feito um estudo comparativo entre as tÃcnicas eletroquÃmicas (VLDA, Cronoamperometria) e ICP-OES para determinaÃÃo de cobre. Os teores de cobre determinados para ambos os mÃtodos encontram-se bem prÃximos, mostrando pequenas variaÃÃes, onde os erros obtidos estÃo distribuÃdos aleatoriamente, apresentando um valor mÃdio de 2,56%. Os testes estatÃsticos realizados mostraram que os resultados obtidos estÃo numa faixa de confianÃa de 95%. Baseado nestes resultados à possÃvel afirmar que as tÃcnicas eletroquÃmicas utilizadas sÃo eficientes na determinaÃÃo de cobre, possibilitando, assim, a validaÃÃo destas por ICP-OES. / The interest for the electroplating of CuNi and its multiple layers is proportionate to the properties of these materials, such as: mechanical resistance to corrosion, mechanical (high tractive force, malleability and ductility) and magnetic properties, beyond its catalytic properties. The voltammetric results suggest that CuNi is electroplated, forming a solid solution. By cyclic voltammetry, the influence of different electrolytic bath in the electroplating of CuNi was investigated, where if it observed the formation of more noble alloys in sulphate baths and tartarate and less noble alloys in citrate and citrate/tartarate medium. Hydrodynamic experiments had been carried through, where it was verified for CuNi in sulphate and tartarate a transport of diffusional mass; for CuNi in citrate and citrate/tartarate was not observed the formation of diffusional plateau, suggesting a transport of mass by charge transference. By dispersive energy of rays-X, the atomic percentage of the constituent of the alloy was determined, where CuNi alloy in sulphate bath and tartarate present a percentage of nickel about 20% and in citrate and citrate/tartarate medium, the percentage of nickel falls espectively for 2% and 4%. By spectrometry of absorption of UV-Vis it was calculated the _ values for individual metals and CuNi, being found low values, indicating that as much the individual metals as the alloy in the different electrolytic transitions d-d type. It was made a comparative study between the electrochemical techniques (Linear Sweep Voltammetry, Chronoamperometry) and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), for copper determination. The copper taxes determined for both methods are near, presenting small variations, where the gotten errors are distributed in a random way presenting an average value of 2,56%. The carried through statistical tests had shown that the gotten results are in a reliable band of 95%. Based in these results it is possible to affirm that the used electrochemical techniques are efficient in the copper determination, making possible, thus, the validation of these for ICP-OES.

Made available in DSpace on 2014-08-20T14:22:02Z (GMT). No. of bitstreams: 1 Tese_Debora_Leitzke_Betemps.pdf: 4121028 bytes, checksum: ee28f25c1660db7ee2ce97d47b512205 (MD5) Previous issue date: 2011-11-28 / Currently consumers are not focused only on the external characteristics of the fruits, as color and size, the internal characteristics such as sugar content and the presence of antioxidant compounds acquires a greater importance in purchasing decisions. The measurement of these parameters is usually done by traditional analysis that presented as main characteristic the sample destruction, beyond being held in a limited number of fruits, normally not representative of the lot or orchard. The optical methods based in visible spectroscopy techniques (Vis) and near-infrared (NIR), as the chlorophyll fluorescence are pointed as a solution of the classic evaluation methods, allowing to assess several components at the same time, without the sample destruction. This study aimed to use the spectroscopy Vis/NIR and the chlorophyll fluorescence as non destructive methods to evaluate quality parameters in peaches, mangos and apples. In peaches it was used the NIR-Case equipment to establish models of calibration for estimating parameters of soluble solids (SS) and flesh firmness for the cultivars Chimarrita, Maciel, Eldorado and Jubileu for two years in a row, being in the second year, it was also evaluated the effect of harvesting time on the calibration models. From the obtained results it can be infer that the attribute soluble solids the calibrations models presented coefficient of determination values acceptable and appropriate to predict the future behavior of the samples in two consecutive years. For flesh firmness only the models developed for the cultivars Jubileu and Eldorado were considered satisfactory, requiring for the others cultivars, new setting for future harvests. The calibration models presented different results over the harvest dates, being the best fits occur in the end of the harvest, fact observed in all peaches cultivars. In mangoes of the cultivar Tommy Atkins and in peaches of the cultivars Eldorado and Jubileu the use of this technique for the separation of fruits in categories according to their maturation stage and monitoring directly from the field using a portable spectrophotometer (DA-meter®) that emits two 9 light signals of wavelength 570 and 720 nm and provides an indes (DA), which correlates with the content of chlorophyll in the peel of the fruit. Through these studies it was conclude that, with the index DA it is possible to separate the mangoes fruits in categories according the maturation degree as well monitor the maturation of the peaches directly from the field, and the relations between these index and quality parameters determinate through the coefficients of determination (R2) were satisfactory. In apples of the cultivars Fuji, Granny Smith and Golden Delicious it was used a sensor based on the technique of chlorophyll fluorescence for the estimation of chlorophyll, anthocyanins and flavonoids present in the skin of the fruit. In general, sides with greater sunlight exposure have higher rates of anthocyanins and flavonois and lower chlorophyll. The correlations between the non-destructive index and the real content of these pigments in the apple skin show the existence of significant correlations the two methods proposed. A negative correlation was found between soluble solids in apples and the chlorophyll fluorescence (CHL) in the far red spectrum. The results also indicate that a single multiparameter sensor of a fluorescence base can provide quality and maturity indices of apples in a nondestructively way. Thus, after the execution of the study, it can be conclude that different methods and technologies have potential for non-destructive evaluation of fruit quality parameters. / Atualmente os consumidores não estão focados apenas nas caracterísiticas externas das frutas, como cor e tamanho, as características internas como teores de açúcares e a presença de compostos antioxidantes passam a ter uma maior importância na decisão de compra. A mensuração destes parâmetros, normalmente é feita através de análises tradicionais que apresentam como característica principal a destrutição da amostra, além de ser realizada em um número restrito de frutas, normalmente não representativo do lote ou do pomar. Os métodos ópticos baseados nas técnicas da espectroscopia do visível (Vis) e do infravermelho próximo (NIR), assim como a fluorescência da clorofila são apontadas como uma evolução dos métodos clássicos de avaliação, permitindo avaliar vários componentes ao mesmo tempo, sem a destruição das amostras. O objetivo da realização deste trabalho foi utilizar a espectroscopia do Vis/NIR e da fluorescência da clorofila como métodos não destrutivos para avaliar parâmetros de qualidade de pêssegos, mangas e maçãs. Em pêssegos utilizou-se o equipamento NIR-Case para o estabelecimento de modelos de calibração para a estimação dos parâmetros sólidos solúveis (SS) e firmeza de polpa para as cultivares Chimarrita, Maciel, Eldorado e Jubileu por dois anos consecutivos, sendo que no segundo ano avaliou-se também o efeito de época de colheita sobre os modelos de calibração. Pelos resultados obtidos podemos inferir que para o atributo SS, os modelos de calibração apresentaram valores de coeficiente de determinação aceitáveis e adequados para prever o comportamento de amostras futuras, nos dois anos consecutivos. Para a firmeza de polpa apenas os modelos desenvolvidos para as cultivares Jubileu e Eldorado foram considerados satisfatórios, necessitando para as demais cultivares, novos ajustes para safras futuras. Os modelos de calibração apresentam resultados diferentes ao longo das datas de colheita, sendo que os melhores ajustes ocorrem no final da safra, fato 7 observado em todas as cultivares de pêssegos. Em mangas da cultivar Tommy Atkins e em pêssegos das cultivares Eldorado e Jubileu, foi testada o uso desta técnica para a separação das frutas em categorias de acordo com o estádio de maturação e acompanhamento desta diretamente no campo, com o uso do espectrofotômetro portátil (DA-meter®) que emite dois sinais luminosos nos comprimentos de onda 670 e 720nm e fornece um índice (DA), que se correlaciona com o conteúdo de clorofila presente na epiderme das frutas. Através destes trabalhos foi possível concluir que, com o índice DA é possível separar as frutas de manga em categorias de acordo com o grau de maturação bem como acompanhar a maturação de pêssegos diretamente no campo, e as relações entre os valores destes índices e os parâmetros de qualidade, determinadas através dos coeficientes de determinação (R2) foram satisfatórios. Em maçãs das cultivares Fuji, Granny Smith e Golden Delicious utilizou-se um sensor com base na técnica da fluorescência da clorofila para a estimação de clorofilas, antocianinas e flavonóides presentes na epiderme das frutas. De uma maneira geral os lados com maior exposição a luz solar apresentaram os maiores índices para os antocianinas e flavonóides e menores para clorofila. As correlações entre os índices não destrutivos e o conteúdo real destes pigmentos nas epidermes das maçãs demonstraram a existência de correlações signifcativas entre os dois métodos propostos. Uma correlação negativa foi encontrada entre o teor de sólidos solúveis em maçãs e a fluorescência da clorofila (CHL) no espectro do vermelho distante. Os resultados também indicam que um sensor multiparamético de base fluorescente pode fornecer índices de maturação e qualidade de maçãs de forma não destrutiva. Sendo assim, após a execução dos trabalhos pode-se concluir que os diferentes métodos e tecnologias não destrutivas apresentam potencial para avaliação dos parâmetros de qualidade em frutas.

Les polyphénols sont abondamment trouvés dans de nombreux fruits, légumes, boissons etc. et ils possèdent de nombreux effets bénéfiques pour la santé. Les méthodes de calcul ont été utilisées dans le cadre de cette thèse pour rationaliser, décrire et prédire les propriétés physiques et chimiques des flavonolignanes et des pyranoanthocyanines pour la compréhension de leurs actions biologiques au niveau moléculaire. Tous les résultats des calculs théoriques ont été discutés par rapport aux données expérimentales. Les propriétés liées à l'activité antioxydante des flavonolignanes ont été étudiées par les méthodes de la théorie de la densité fonctionnelle (DFT). La dépendance au pH des propriétés d'absorption UV/Vis des flavonolignanes et des pyranoanthocyanines ont été évaluée par des méthodes DFT dépendante du temps (TD-), et les interactions non-covalentes ont été étudiées avec les méthodes de DFT incluant la correction de dispersion. Un bref aperçu est également donné sur l'interaction de ces composés avec des biomolécules. Le chapitre 6 présente des résultats non encore publiés de plusieurs systèmes non-covalents pigment: copigment. Cette partie des résultats constitue un bon point de départ pour la recherche du ‘meilleur copigment’. / Polyphenols are abundantly found in many fruit, vegetables, beverages, etc. and they possess many potential health benefits. Computational methods were thoroughly used through this thesis to rationalize, describe and predict physical chemical properties of flavonolignans and pyranoanthocyanins. Here, we aim at an understanding of polyphenol biological actions at a molecular level. All outcomes from the theoretical computations were discussed with respect to experimental data. The properties related to antioxidant activity of flavonolignans were investigated by density functional theory (DFT) methods. The pH dependence of ultraviolet/visible (UV/Vis) absorption properties of flavonolignans and pyranoanthocyanins were evaluated by time dependent (TD-) DFT methods, and noncovalent interactions were investigated within dispersion-corrected DFT methods. A short overview is also given on interaction of such compounds with biomolecules. Chapter 6 presents yet not published results of several noncovalent pigment: copigment systems. This part of the results serves as a good starting point to search for ‘the best copigment’.

This thesis is focused on the application of two working electrodes of graphite suitable for determination of oxidizable tumour biomarkers. It deals with the study of electrochemical behavior of urinary indican. For the determination the technique of differential pulse voltammetry (DPV) was used on carbon paste electrode and film composite paste electrode in Britton-Robinson (BR) buffer. In the first step optimal conditions were determined to find the lowest limit of determination (LQ) of this substance. BR buffer of pH 3 was chosen as the optimum medium for determination on a carbon paste electrode and BR buffer of pH 2 was used as the optimum medium for the determinaton using a film composite electrode. Performance for both electrodes was observed in a concentration range of from 1 · 10-6 to 5 · 10-5 mol·l-1 . The limit of determination for measurements on a carbon paste electrode was 0.7 µmol·l-1 and the film composite electrode was 1.7 µmol·l-1 . Possibility of the acummulation of indican was examined in order to increase sensitivity and decrease of limit of quantification. However, after 5 minute sorption, no increase in response was observed and the accumulation step was not inserted. Developed method was tested on the determination of urinary indican in human urine matrix after solid phase...

This master´s thesis deals with the study of the incorporation of low and high molecular weight substances into liposomal systems. The aim of the work was to determine the encapsulation efficiency (EE) of the active substance and the influence of individual components of the liposomal system on EE. Liposomes were prepared from dipalmitoylphosphatidylcholine. They were stabilized by cholesteroland and phosphatidic acid was added to give a negative charge. Stealth properties gain the binding of polyethylene glycol and other trimethyl chitosan we enabled the entry of liposomes into the bloodstream by the paracellular pathway. Vitamin C and the enzyme bromelain were used for incorporation into liposomes. UV-VIS spectrophotometry was used to determine the encapsulation efficiency of liposomes prepared by combining the individual components. It has been suggested that vitamin C and the enzyme can be incorporated into liposomes, but an enzyme with a higher EE. Furthermore, phosphatidic acid and trimethyl chitosan have been found to affect EE, which increases the EE of vitamin C and decreases the EE of the enzyme.

This master´s thesis deals with the study on mechanical and transport properties of hybrid hydrogel systems. Considering applications of hydrogels, especially in chemical industry, pharmacy, or eventually medical applications, for the study gellan and alginate-based hydrogels were selected. In order to compare individual characteristics physical and hybrid hydrogels were prepared. Gellan hydrogels were prepared in deionization aqua solution, calcium chloride dihydrate and tween 80 solution. Alginate hydrogels were prepared in calcium chloride dihydrate solution as well, and polyacrylamide with N,N´–methylenbisacrylamide. For the study of mechanical properties moisture analyser and rheology measurements were selected. Transport properties were studied using the diffusion experiments combined with UV-VIS spectroscopic detection. Concluding of this thesis is summarization of measured values, which provides comprehensive review of the problematics. It was discovered that the conveniently selected concentrations of structural components of hydrogel matrix and the additives can influence both the mechanical as well as the transport properties of studied hydrogels.

This diploma thesis is concentrated on the interactions between polyelectrolyte (hyaluronan) and cationic surfactant (CTAB). The experiments were performed in an aqueous solution and in an environment of physiological ionic strength (0,15mmoldm-3 NaCl). The determination of the surfactant concentration in solutions was based on the formation of colored complexes of CTAB and picric acid in chloroform. The concentrations of surfactant were measured by UV-VIS spectroscopy. The stability of CTAB+HyA was examined by a dialysis method. The results showed that, regardless of the environment, the presence of HyA in solution reduces the number of free molecules of CTAB which can be determined in the sample. It has been proved that there is an interaction between HyA and surfactant and that CTAB has greater affinity for HyA then for the picric acid. The stability of CTAB+HyA was determined by dialysis of 120 hours. After that time, the concentrations of the retentate and permeate were settled. The results showed that in the membrane remains a certain amount of CTAB bounded to hyaluronan. The system can be suitable for the preparation of targeted carriers of biologically active substances.

This diploma thesis deals with humic acid gels and their ability to bind metallic ions on their surface. In the thesis, there was studied the adsorption of copper ions on the provided gels. The gels were prepared by dissolving the humic acid in sodium hydroxide or sodium tripolyphosphate and then precipitated with hydrochloric acid or metal chlorides. Adsorption was studied at different concentrations of the copper (II) chloride and measured on UV-VIS spectrophotometer. It was proved from measuring that gels made from sodium tripolyphosphate are adsorbing less copper ions than the ones prepared by sodium hydroxide. Also, the copper ions are bound with smaller force on gels prepared with polyphosphate. Gels precipitated with magnesium chloride adsorb much more than gels precipitated with acid, thus in the case of gels sequestered metal ions extracted higher.

Presented diploma thesis deals with the analysis of juices of selected red and white currant varieties. The theoretical part is dedicated to the characteristics of a currant, biologically active substances of its fruits, its growing proces and the utilization of currants in the food industry. The analyzed parameters of currants - phenolics, anthocyanins and vitamin C are also characterized in the theoretical part with possibůe methods of their determination. The experimental part is devoted to the preparation of samples and the working practices of individual analysis. Six selected varieties of white and eleven varieties of red currant from Research and Breeding Institute of Pomology Holovousy Ltd. and six varieties of white and ten varieties of red currant from private grower were used for the analysis. Total phenolics and anthocyanins were determined spectrophotometrically, the content of vitamin C was determined by HPLC. Higher values of these compounds were measured mainly in the varieties of Research and Breeding Institute of Pomology Holovousy Ltd. Varieties of red currants contained higher amounts of total phenolics and anthocyanins while white currants contained higher amounts of vitamin C.