The Maya of Central America developed a complex society: among their many achievements they developed a writing system, complex calendar and were prolific builders. The buildings of their large urban centres, such as Copan in Honduras, were decorated with painted stucco, moulded masks, carving and elaborate murals, using a range of coloured pigments. In this study the paints used on the buildings of Copan and some ceramic sherds have been investigated, non-destructively, using micro-Raman spectroscopy, micro-ATR infrared spectroscopy, environmental scanning electron microscopy with energy dispersive X-ray analysis (ESEM-EDX) and FTIR-ATR imaging spectroscopy. The paint samples come from four buildings and one tomb covering three time periods in the four hundred year history of Copan. The main pigment used in the red paint on these samples was identified as haematite, and the stucco as a mixture of calcite particles dispersed throughout a calcite-based lime wash stucco. The composition and physical nature of the stucco changed through time, indicating a refining of production techniques over this period. A range of minor mineral components have been identified in each of the samples including rutile, quartz, clay and carbon. The presence and proportion of these and other minerals differed in each sample, leading to unique mineral signatures for the paint from each time period. Green and grey paints have also been identified on one of the buildings, the Rosalila Temple. The green pigment was identified as a celadonite-based green earth, and the grey pigment as a mixture of carbon and muscovite. The combination of carbon and mica to create a reflective paint is a novel finding in Maya archaeology. The high spatial resolution of the micro-FTIR-ATR spectral imaging system has been used to resolve individual particles in tomb wall paint and to identify their mineralogy from their spectra. This system has been used in combination with micro-Raman spectroscopy and ESEM-EDX mapping to characterize the paint, which was found to be a mixture of haematite and silicate particles, with minor amounts of calcite, carbon and magnetite particles, in a sub-micron haematite and calcite matrix. The blending of a high percentage of silicate particles into the haematite pigment is unique the tomb sample. The stucco in this tomb wall paint has finely ground carbon dispersed throughout the top layer providing a dark base for the paint layer. Changing paint mixtures and stucco composition were found to correlate with changes in paint processing techniques and building construction methods over the four hundred years of site occupation.

Les  catalyseurs impliqués dans le procédé d’hydrodésulfurisation des essences (HDS) reposent sur l’utilisation principale d’une phase active MoS2 promue par du cobalt et supportée sur alumine. L’enjeu de cette thèse est de faire le lien entre les propriétés spécifiques propres du catalyseur et ses performances catalytiques. Trois paramètres ont été étudiés afin de tenter de comprendre l’origine de leurs propriétés catalytiques : la nature du support (γ-Al2O3, δθ-Al2O3, SiO2), la densité surfacique en molybdène et le ratio cobalt/molybdène. L’activité HDS et la sélectivité ont été mesurées en réalisant des tests catalytiques sous haute pression en présence de molécules modèles. En parallèle, la phase CoMoS a été caractérisée  par XPS et HRTEM pour déterminer sa spéciation et sa structure (taille de feuillet et empilement). De plus, ces deux techniques combinées aux calculs quantiques ab initio ont permis de développer un modèle morphologique 2D d’un feuillet de phase CoMoS en dénombrant la nature (Co ou Mo) des atomes localisés aux bords du feuillet. Pour les supports étudiés, une corrélation entre l’activité HDS et le nombre d’atomes de cobalt aux bords du feuillet CoMoS a été établie. Ceci a été possible en considérant aussi l’empilement, paramètre pertinent. Ensuite, les analyses en HRSTEM réalisées sur les catalyseurs CoMoS sur γ et δ-Al2O3 ont révélé l’effet des facettes de l’alumine d d’une part, et le possible effet des arrêtes et coins de γ-Al2O3 d’autre part, sur la taille des feuillets CoMoS.Une étude spectroscopique FTIR de l’adsorption de la molécule sonde NO combinée à des calculs ab initio, a permis de mettre en évidence la nature des sites actifs de la phase CoMoS en fonction du support étudié. Les résultats spectroscopiques obtenus en présence du catalyseur supporté sur silice se sont révélées en adéquation avec la faible activité HDS observée.Une unité a également été conçue dans le but d’étudier ces catalyseurs par GC-DRIFT and GC-ATR in situ. La mise en contact de réactifs modèles en présence de la phase CoMoS et de son support dans des conditions de réaction d’HDS a alors pu être réalisée pour la première fois. Lors de l’adsorption et désorption du 3-methylthiophene (non réversible et réversible) sur les catalyseurs supportés sur γ-Al2O3 et SiO2, une réactivité particulière en présence de 3MT a été observée selon le support et la présence de la phase CoMoS. En présence d’H2, de nouveaux modes  vibrationnels liés à l’adsorption et/ou à la réactivité du 3MT ont été mis en évidence. / Catalysts used in the selective gasoline hydrodesulphurization (HDS) process are mainly cobalt promoted MoS2 active phase (CoMoS) supported on alumina. The aim of this work is to explore correlation between specific features of those HDS catalysts and their catalytic performances. Three parameters are studied to understand the catalytic performances of HDS catalysts: the nature of the support (γ-Al2O3, δθ-Al2O3, SiO2), the molybdenum surface density and the cobalt/molybdenum ratio. HDS activity and selectivity are measured by performing high pressure catalytic tests on model molecules. In parallel, characterizations of the CoMoS phase were performed by XPS and HRTEM analysis to determine the chemical speciation and structure (size and stacking) of the active phase. Additionally, these techniques are combined with previous ab initio quantum calculations to develop a 2D morphology model of the CoMoS slab by considering the location of cobalt atoms at the edges of the slab. For the three supports, a correlation is found between the HDS activity and the number of Co atoms at the slab edges. The normalization by stacking appears to be necessary to obtain this correlation. Moreover, HRSTEM analysis on CoMoS on δθ-Al2O3 and γ-Al2O3 reveals the impact of the facets of dq-alumina crystallites and the possible role of corner and edges of g-Al2O3 crystallites on the size of the CoMoS slabs. The FTIR spectroscopic study of the adsorption of the NO probe molecule combined with ab initio calculations enables the identification of the nature of the active sites of the CoMoS phase as a function of the support. The spectroscopic features revealed for the silica supported catalyst are in line with its lower HDS activity. Simultaneously, an innovative experimental set up for in situ GC-DRIFT and GC-ATR analysis has been built on-purpose for studying the catalysts. It allows the investigation of the interactions of model reactants contacting the CoMoS phase and its supports close to HDS reaction conditions. This technique shows distinct behaviors of the adsorption and desorption process (non-reversible and reversible) of 3-methylthiophene (3MT) on γ-Al2O3 and SiO2 supported catalysts due to specific surface reactivity towards 3MT depending on the support and the presence of the CoMoS phase. Moreover, the presence of H2 modified the vibrational adsorption modes of 3MT linked to its adsorption and/or reactivity.

Les biofilms sont des communautés complexes de microorganismes, enchassées dans une matrice auto-secrétée de substances polymériques extracellulaires ou EPS. Les biofilms se forment à la surface de la plupart des matériaux, qu’ils soient de nature biologique ou non, et sont à l’origine de divers problèmes économiques et sanitaires. Les bactéries dans un biofilm, dites bactéries sessiles, présentent en effet des propriétés phénotypiques qui les distinguent de leurs homologues planctoniques, notamment par une résistance accrue aux antibiotiques et aux traitements de désinfection. D’où, la nécessité de prévenir leur formation et/ ou de leur élimination à partir de stratégies mieux adaptées à ce mode de vie en communauté. Le développement de telles stratégies passe entre autre par une meilleure connaissance des contributions physico-chimiques gouvernant les interactions de ces microorganismes avec leur environnement proche notamment lors des étapes initiales de la formation des biofilms. Deux grands objectifs ont été fixés au début de cette thèse, le premier visant à caractériser, in situ et en temps réel la formation de jeunes biofilms de deux modèles bactériens : une souche naturelle et ubiquitaire de Pseudomonas fluorescens et une souche modèle d’Escherichia coli obtenue par génie génétique pour surexprimer un seul type d’EPS. Le deuxième objectif de cette thèse, consiste à étudier leurs réponses à un stress environnemental ou chimique, notamment quand les biofilms doivent se développer dans des conditions extrêmes de pH. Pour atteindre ces objectifs, différentes techniques ont été combinées pour étudier de l’échelle moléculaire à l’échelle cellulaire le développement des biofilms. La spectroscopie Infrarouge à Transformée de Fourier en mode réflexion totale atténuée (FTIR-ATR) a été utilisée pour suivre en temps réel le développement des biofilms. Nous avons pu suivre l’évolution des empreintes spectrales IR-ATR au cours de la formation des biofilms, sous des conditions favorables ou non à leur croissance. De jeunes biofilms de 24 h ont été étudiés par microspectroscopie Raman confocale (MRC), celle ci permettant d’obtenir des informations localisées sur la composition chimique des biofilms. La structure générale des biofilms a été visualisée par la microscopie à épifluorescence. Finalement, les propriétés physico-chimiques des EPS ont été quantifiées par spectroscopie de force atomique à l’échelle de la molécule unique (SMFS pour Single Molecule Force Spectroscopy). / Biofilms are complex communities of microorganisms, embedded in an auto-produced matrix of extracellular polymeric substances or EPS. Biofilms form on the surface of most materials, whether or not they are of biological nature, and cause major economic problems as well as public health concerns. Bacteria within a biofilm also called sessile bacteria, have phenotypic characteristics that distinguish them from their planktonic counterparts, rendering them more resistant to antibiotics and to disinfection strategies. Hence, the prevention of their formation and/ or their elimination requires the use of strategies that are well suited to the sessile mode of life. The development of these strategies begins with a better understanding of the physicochemical contributions that govern the interaction between the sessile community and its environment especially during the first steps of biofilm formation. Two main objectives were defined at the beginning of this thesis, the first was to characterize, in situ, and in real time the development of nascent biofilms. Two bacterial models were studied: a natural and ubiquitous strain of Pseudomonas fluorescens and a model strain of Escherichia coli genetically modified to overexpress one type of EPS. The second objectif was to study their responses towards an environmental or chemical stress; particularly how their development would be affected under extreme conditions of pH. To gain these objectives, different techniques were combined to study from the molecular to the cellular scale the development of biofilms. Fourier Transform Infrared spectroscopy in attenuated total reflection mode was used to evaluate in real time the development of biofilms. We were able to detect changes in the IR-ATR spectral profile along biofilm formation under favorable and non favorable growth conditions. 24 h - old biofilms were characterized using confocal Raman microspectroscopy, which allowed us to gather localized information on their chemical composition. The structure of biofilms was visualized using epifluorescence microscocopy. Finally, physico-chemical properties of EPS were quantified using single molecule force spectroscopy

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O objetivo deste trabalho foi estabelecer um modelo empregando-se ferramentas de regressão multivariada para a previsão do teor em ésteres metílicos e, simultaneamente, de propriedades físico-químicas de misturas de óleo de soja e biodiesel de soja. O modelo foi proposto a partir da correlação das propriedades de interesse com os espectros de reflectância total atenuada no infravermelho médio das misturas. Para a determinação dos teores de ésteres metílicos foi utilizada a cromatografia líquida de alta eficiência (HPLC), podendo esta ser uma técnica alternativa aos método de referência que utilizam a cromatografia em fase gasosa (EN 14103 e EN 14105). As propriedades físico-químicas selecionadas foram índice de refração, massa específica e viscosidade. Para o estudo, foram preparadas 11 misturas com diferentes proporções de biodiesel de soja e de óleo de soja (0-100 % em massa de biodiesel de soja), em quintuplicata, totalizando 55 amostras. A região do infravermelho estudada foi a faixa de 3801 a 650 cm-1. Os espectros foram submetidos aos pré-tratamentos de correção de sinal multiplicativo (MSC) e, em seguida, à centralização na média (MC). As propriedades de interesse foram submetidas ao autoescalamento. Em seguida foi aplicada análise de componentes principais (PCA) com a finalidade de reduzir a dimensionalidade dos dados e detectar a presença de valores anômalos. Quando estes foram detectados, a amostra era descartada. Os dados originais foram submetidos ao algoritmo de Kennard-Stone dividindo-os em um conjunto de calibração, para a construção do modelo, e um conjunto de validação, para verificar a sua confiabilidade. Os resultados mostraram que o modelo proposto por PLS2 (Mínimos Quadrados Parciais) foi capaz de se ajustar bem os dados de índice de refração e de massa específica, podendo ser observado um comportamento aleatório dos erros, indicando a presença de homocedasticidade nos valores residuais, em outras palavras, o modelo construído apresentou uma capacidade de previsão para as propriedades de massa específica e índice de refração com 95% de confiança. A exatidão do modelo foi também avaliada através da estimativa dos parâmetros de regressão que são a inclinação e o intercepto pela Região Conjunta da Elipse de Confiança (EJCR). Os resultados confirmaram que o modelo MIR-PLS desenvolvido foi capaz de prever, simultaneamente, as propriedades índice de refração e massa específica. Para os teores de éteres metílicos determinados por HPLC, foi também desenvolvido um modelo MIR-PLS para correlacionar estes valores com os espectros de MIR, porém a qualidade do ajuste não foi tão boa. Apesar disso, foi possível mostrar que os dados podem ser modelados e correlacionados com os espectros de infravermelho utilizando calibração multivariada / In the present work, a model that uses multivariate regression tools was proposed to predict both contents of methyl esters and physical-chemical properties of soybean oil -soybean biodiesel blends. The model was proposed from the correlation of the properties of interest with the attenuated total reflectance infrared spectra of the samples (ATR/MID-FTIR). The composition of the blends (methyl esters content) was determined by high performance liquid chromatography (HPLC), which can be seen as an alternative technique to the standard reference methods based on gas chromatography (EN 14103 and EN 14105). The selected physicochemical properties were refractive index, density, and viscosity. For the study, 11 mixtures were prepared with different proportions of soybean biodiesel and soybean oil (0-100 % wt of soybean biodiesel) in five replications totalizing 55 samples. The infrared spectra were acquired in the range 3801-650 cm-1. The spectra were submitted to the multiplicative signal correction (MSC) and then to mean centering (MC) preprocessing. The properties of interest were submitted to auto scale. It was then applied principal component analysis (PCA) for the purpose of reducing the dimensionality of the data, and detected the presence of outliers. When the outliers were detected, the samples were discarded. The original data were submitted to Kennard-Stone algorithm dividing them into a calibration set to build the model and the validation to verify its reliability. The results showed that the model proposed by PLS2 (Partial Least Squares) was able to adjust well to the refractive index data and density, can be observed a random behavior of errors, indicating the presence of homoscedasticity in residual values, in other words, the constructed model presented a forecast of capacity for specific mass properties and refractive index with 95% confidence. The accuracy of the model was evaluated by estimating the regression parameters which are the slope and the intercept by EJCR (Joint Region Confidence Ellipse). The results confirmed that MIR-developed PLS model was able to predict both the refractive index and specific gravity properties. For contents of methyl esters via liquid chromatography the model showed a lower adjustment of the data. Nevertheless, it was possible to demonstrate that the results obtained from methyl esters by HPLC analytical method can be modeled and correlate them with infrared spectra using multivariate calibration

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O objetivo deste trabalho foi estabelecer um modelo empregando-se ferramentas de regressão multivariada para a previsão do teor em ésteres metílicos e, simultaneamente, de propriedades físico-químicas de misturas de óleo de soja e biodiesel de soja. O modelo foi proposto a partir da correlação das propriedades de interesse com os espectros de reflectância total atenuada no infravermelho médio das misturas. Para a determinação dos teores de ésteres metílicos foi utilizada a cromatografia líquida de alta eficiência (HPLC), podendo esta ser uma técnica alternativa aos método de referência que utilizam a cromatografia em fase gasosa (EN 14103 e EN 14105). As propriedades físico-químicas selecionadas foram índice de refração, massa específica e viscosidade. Para o estudo, foram preparadas 11 misturas com diferentes proporções de biodiesel de soja e de óleo de soja (0-100 % em massa de biodiesel de soja), em quintuplicata, totalizando 55 amostras. A região do infravermelho estudada foi a faixa de 3801 a 650 cm-1. Os espectros foram submetidos aos pré-tratamentos de correção de sinal multiplicativo (MSC) e, em seguida, à centralização na média (MC). As propriedades de interesse foram submetidas ao autoescalamento. Em seguida foi aplicada análise de componentes principais (PCA) com a finalidade de reduzir a dimensionalidade dos dados e detectar a presença de valores anômalos. Quando estes foram detectados, a amostra era descartada. Os dados originais foram submetidos ao algoritmo de Kennard-Stone dividindo-os em um conjunto de calibração, para a construção do modelo, e um conjunto de validação, para verificar a sua confiabilidade. Os resultados mostraram que o modelo proposto por PLS2 (Mínimos Quadrados Parciais) foi capaz de se ajustar bem os dados de índice de refração e de massa específica, podendo ser observado um comportamento aleatório dos erros, indicando a presença de homocedasticidade nos valores residuais, em outras palavras, o modelo construído apresentou uma capacidade de previsão para as propriedades de massa específica e índice de refração com 95% de confiança. A exatidão do modelo foi também avaliada através da estimativa dos parâmetros de regressão que são a inclinação e o intercepto pela Região Conjunta da Elipse de Confiança (EJCR). Os resultados confirmaram que o modelo MIR-PLS desenvolvido foi capaz de prever, simultaneamente, as propriedades índice de refração e massa específica. Para os teores de éteres metílicos determinados por HPLC, foi também desenvolvido um modelo MIR-PLS para correlacionar estes valores com os espectros de MIR, porém a qualidade do ajuste não foi tão boa. Apesar disso, foi possível mostrar que os dados podem ser modelados e correlacionados com os espectros de infravermelho utilizando calibração multivariada / In the present work, a model that uses multivariate regression tools was proposed to predict both contents of methyl esters and physical-chemical properties of soybean oil -soybean biodiesel blends. The model was proposed from the correlation of the properties of interest with the attenuated total reflectance infrared spectra of the samples (ATR/MID-FTIR). The composition of the blends (methyl esters content) was determined by high performance liquid chromatography (HPLC), which can be seen as an alternative technique to the standard reference methods based on gas chromatography (EN 14103 and EN 14105). The selected physicochemical properties were refractive index, density, and viscosity. For the study, 11 mixtures were prepared with different proportions of soybean biodiesel and soybean oil (0-100 % wt of soybean biodiesel) in five replications totalizing 55 samples. The infrared spectra were acquired in the range 3801-650 cm-1. The spectra were submitted to the multiplicative signal correction (MSC) and then to mean centering (MC) preprocessing. The properties of interest were submitted to auto scale. It was then applied principal component analysis (PCA) for the purpose of reducing the dimensionality of the data, and detected the presence of outliers. When the outliers were detected, the samples were discarded. The original data were submitted to Kennard-Stone algorithm dividing them into a calibration set to build the model and the validation to verify its reliability. The results showed that the model proposed by PLS2 (Partial Least Squares) was able to adjust well to the refractive index data and density, can be observed a random behavior of errors, indicating the presence of homoscedasticity in residual values, in other words, the constructed model presented a forecast of capacity for specific mass properties and refractive index with 95% confidence. The accuracy of the model was evaluated by estimating the regression parameters which are the slope and the intercept by EJCR (Joint Region Confidence Ellipse). The results confirmed that MIR-developed PLS model was able to predict both the refractive index and specific gravity properties. For contents of methyl esters via liquid chromatography the model showed a lower adjustment of the data. Nevertheless, it was possible to demonstrate that the results obtained from methyl esters by HPLC analytical method can be modeled and correlate them with infrared spectra using multivariate calibration

O conhecimento da composição do petróleo e seus produtos é uma necessidade imprescindível numa refinaria para o ajuste das condições do processo. A espectroscopia de infravermelho próximo (NIR) apresenta-se como uma ferramenta útil para atender esta necessidade, por sua grande potencialidade e aplicações. Neste contexto, foi desenvolvida a metodologia experimental da espectroscopia NIR, através de dois tipos de sensores: transmissão (Sistema de transmitância) e refletância total atenuada ATR (Sistema ATR). Foram analisadas 63 amostras de petróleo no Sistema de transmitância e 41 amostras no Sistema ATR. O API das amostras oscila entre 29,8 e 35,6. Na primeira etapa do trabalho foram obtidos os espectros NIR e cromatografias SIMDIS (Destilação Simulada) das amostras de petróleo, e dos dados obtidos foram eliminadas algumas amostras por apresentar pontos discrepantes. Na segunda fase foi realizada a análise dos espectros no esquema OFF-LINE, em ambos sistemas, escolhendo como faixa espectral a região de 5600 a 6000 cm-1 que corresponde a regiões de sobretons do NIR para os hidrocarbonetos. Também foram realizados testes de repetibilidade dos espectros e testes sobre a influência do comprimento das fibras ópticas utilizadas. Foi realizado um pré-tratamento dos espectros, com a finalidade de fazer as informações contidas neles mais sensíveis às diferenças. Assim mesmo, foi desenvolvida a análise dos espectros no esquema ON-LINE, com um LOOP fechado, para o sistema de transmitância, com óleo Diesel e petróleo bruto, para testar as variações de temperatura e velocidade de escoamento nos espectros. Nesta etapa também foram realizados testes de repetibilidade a diferentes temperaturas. A fase seguinte foi o desenvolvimento do modelo da rede neural (RN). As variáveis de entrada do processo são os espectros de absorção pré-tratados, arbitrariamente representados em 20 comprimentos de onda e o grau API do petróleo. As variáveis de saída da rede são as porcentagens em peso da SIMDIS. / The knowledge of the petroleum composition and its products is an indispensable tool in a refinery for the process conditions settlement. The Near Infrared Spectroscopy (NIR) presents-itself as a helpful tool that attends to this need, because of its high potential and applications. In this context, it was developed the experimental methodology for NIR spectroscopy using two kinds of sensors: Transmission (Transmission system) and Attenuated Total Reflectance (ATR system). There were analyzed 63 petroleum samples by transmission system and 41 samples by the ATR system. The API degree of the samples ranges from 29,8 to 35,6. In the first step of this work, NIR spectra and SIMDIS chromatography data (Simulated Distillation) of the petroleum samples were obtained. From these data some samples were eliminated due to the presence of inconsistent points. In the second step, the analysis of the spectra OFF-LINE was carried out. In both systems, by choosing the region of 5600 to 6000 cm-1 as the spectral range which corresponds to the NIR overtone region for the hydrocarbons. Moreover, repeatability tests for the spectra were carried out and tests about the influence of the optical fibers on them. A pre spectrum treatment was carried out in order to become their information more sensible to the differences. Besides, the ON-LINE spectrum analysis by a closed LOOP were developed for the transmission system, with oil diesel and petroleum, in order to test the effect of the temperature and flow rate variations on the spectra. In this step, tests of repeatability at different temperatures were also carried out. In the following step, it was developed the Neural Network (RN) model. The entry variables of the data input are the random absorption spectra represented in 20 wavelengths with pre processing and the petroleum API degree. The net output variables are the weight percentages of the SIMDIS.

Orientadores: Florencia Cecilia Menegalli, Paulo Jose do Amaral Sobral / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-10T03:02:54Z (GMT). No. of bitstreams: 1 AraujoFarro_PatriciaCecilia_D.pdf: 11234576 bytes, checksum: 783552b6dbe46ec622ef24d255cee671 (MD5) Previous issue date: 2008 / Resumo: O grão de quinoa (Chenopodium quinoa, Willdenow) é um pseudocereal originário da América do Sul Andina, que tem gerado interesse industrial crescente e cultivo diversificado em diversos países de América do Norte e da Europa. Recentemente nos países da América Latina tem-se despertado um interesse comum na busca de tecnologias de desenvolvimento de biomateriais, como uma forma de diminuir a poluição gerada pelos resíduos sintéticos, utilizando os recursos naturais próprios da região. O Brasil destaca-se pela sua preocupação pelo meio ambiente e manutenção das fontes destes recursos, através de programas experimentais de adaptação de culturas, como a quinoa, nos cerrados brasileiros, com resultados satisfatórios. O uso potencial da quinoa na indústria alimentícia tem sido alvo de estudos diversos. No entanto, é pouco explorada a aplicabilidade de produtos derivados deste grão, como farinhas e amido, na área de biomateriais. Dentro desse contexto, os principais objetivos deste trabalho foram: (1) desenvolver tecnologias pouco agressivas de extração de matérias-primas a partir do grão de quinoa: farinha integral (FI); farinha por extração úmida (FU) e amido (AQ); (2) caracterização das propriedades físico-químicas e estruturais destes produtos; (3) análises reológicas de soluções formadoras de filmes a partir do amido; (4) avaliação de diferentes formulações utilizadas na elaboração de filmes utilizando um planejamento fatorial completo analisando os efeitos de concentração de glicerol, do pH da solução filmogênica, e das condições de secagem (T(ºC) / t (horas)) em função da solubilidade e das propriedades mecânicas dos filmes; (5) otimização do processo de elaboração de filmes e caracterização dos filmes ótimos quanto às propriedades termomecânicas, óticas e estruturais, e cristalinidade (FTIR e Raios X). Os filmes elaborados a partir das diferentes matérias-primas obtidas do grão de quinoa foram elaborados utilizando 4% de matéria prima/ 100 g de solução filmogênica. Esta porcentagem da matéria prima foi determinada através das análises reológicas. Foi utilizado um planejamento fatorial completo 23, onde as três variáveis independentes foram: concentração de glicerol (16,6; 20; 25; 30 e 33,4 g/100 g matéria-prima), nível de pH de soluções filmogênica (9,7; 10; 10,5; 11 e 11,3) e condições de secagem (30°C/20h; 34°C/17h; 40°C/10h; 46°C/9h e 50°C/5h). As variáveis respostas foram: teste mecânico de tração (força na tração e elongação no ponto de ruptura); teste mecânico de perfuração (força na perfuração e deformação na perfuração) e solubilidade em água a 25ºC. Uma vez determinadas as equações dos modelos matemáticos, foi aplicada a função desejabilidade para estabelecer as condições ótimas de elaboração de filmes. Para o filme de amido de quinoa, a condição ótima foi obtida com concentração de glicerol de 21,2%, pH de 10,7 e condição de secagem de 36ºC/14h. Para o filme de FU: Concentração de glicerol de 21%, nível de pH de 10,48 e condição de secagem de 42ºC/8h. E para o filme de FI foi de concentração de glicerol de 20%, nível de pH de 10,6 e condição de secagem de 38ºC/12h. Os filmes de amido de quinoa mostraram-se incolores e pouco opacos, apresentando reduzida solubilidade em água e boa resistência à tração e flexibilidade. Os filmes de farinha por extração úmida apresentaram leve cor amarela, moderada opacidade e flexibilidade. Já os filmes de farinha integral apresentaram cor amarela intensa, moderada opacidade, alta flexibilidade mas baixa resistência no teste de tração / Abstract: Quinoa (Chenopodium quinoa, Willdenow) is a native and oldest pseudocereal grain from the Andean region in South America. Nowadays, due to an increasing industrial interest, quinoa seeds are grown in different countries as in North America and Europe. Recently, Latin American countries have shared a common interest regarding the use of natural resources in technologies capable of minimizing pollution. In that sense, special attention has been given towards the development of new biomaterials that could diminish synthetic residues. In the last years, Brazil participated in experimental programs of culture adaptation, with satisfactory results for quinoa crops. In spite of the great amount of studies concerning the potential use of quinoa in the food industry, the use of the quinoa seeds as source of starch and flour and their applicability in the biomaterials development field has not yet been fully explored. The aims of this work were: (1) to develop a non aggressive raw material (starch and flours) extraction technique, (2) determine the structural and physical-chemical properties of the quinoa products (3) characterization of the film-forming solutions through rheological analyses (4) to evaluate the effects of the glycerol content, pH and drying conditions of film-forming solutions on some functional properties of its edible films using an experimental design (response surface methodology). The responses were mechanical properties as puncture strength, puncture deformation, tensile strength, elongation and Young modulus and solubility, (5) optimization of the films elaborative process and characterization (thermomechanical, optical and structural properties, and crystallinity - FTIR and X-ray) of the optimal quinoa films. According to an experimental design 23, films were produced from film forming solutions (FFS) containing 4g of Quinoa products (QP) /100g of FFS (this percentage of QP was determined by rheological tests), glycerol (16.6, 20.0, 25.0, 30.0 and 33.4 g/100 g starch) used as a plasticizer, and a constant pH of FFS (9.7, 10.0, 10.5, 11.0 and 11.3). Drying conditions varied from temperature and time (30°C/20h; 34°C/17h; 40°C/10h; 46°C/9h and 50°C/5h) in an oven with circulation and renewal of air. The five levels of each variable were coded as -1.68, - 1, 0, +1, +1.68. All tests were run at room conditions (22-25ºC and 55-65% relative humidity) using samples previously conditioned at 58% of relative humidity at 22-25ºC for 7 days. The optimal films elaboration conditions were determined by the desirability function. For each quinoa product, conditions were different. For films based on starch (S), the optimal condition was obtained when using 21,2% glycerol content, pH= 10,7 and drying condition of 36ºC/14h, for films of flour extracted by wet milling (FWM), 21% glycerol content, pH= 10,48 and drying condition of 42ºC/8h, and, finally, for films of whole flour (WF), 20% glycerol content, pH= 10,6 and drying condition of 38ºC/12h The S films were colorless and scarcely opaque, showed reduced water solubility, and presented good qualities of tensile strength. FWM films presented a yellowish color, moderate opacity, tensile strength and flexibility. WF films presented an intense yellowish color, moderate opacity and high flexibility but low tensile strength / Doutorado / Doutor em Engenharia de Alimentos

Submitted by Geandra Rodrigues (geandrar@gmail.com) on 2018-07-13T14:13:42Z No. of bitstreams: 1 carolinacarvalhoramosviana.pdf: 2071193 bytes, checksum: ced9ed600a8408dfa84aa8a442fdff6f (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-07-16T17:33:13Z (GMT) No. of bitstreams: 1 carolinacarvalhoramosviana.pdf: 2071193 bytes, checksum: ced9ed600a8408dfa84aa8a442fdff6f (MD5) / Made available in DSpace on 2018-07-16T17:33:13Z (GMT). No. of bitstreams: 1 carolinacarvalhoramosviana.pdf: 2071193 bytes, checksum: ced9ed600a8408dfa84aa8a442fdff6f (MD5) Previous issue date: 2018-03-28 / Este trabalho tem como objetivo geral a utilização da Espectroscopia na região do Infravermelho Médio, aliada à calibração multivariada (PCA e PLS) para caracterizar e quantificar a composição majoritária de fórmulas infantis. Foram avaliadas 20 marcas comercializadas em Juiz de Fora (MG), de quatro grandes indústrias do ramo. Determinou-se a composição majoritária das amostras (teor de lipídios, proteína verdadeira, carboidratos, umidade, sólidos totais e cinzas) por meio de métodos físico-químicos, em duplicata, de acordo com metodologias oficiais de análise, sendo que os resultados, em geral, atendem a legislação vigente. Em acréscimo, foi realizada a avaliação espectroscópica das formulações, na região MIR de 4000 cm-1 a 400 cm-1. Utilizando-se de ferramentas estatísticas, foi possível interpretar os espectros gerados e caracterizar a composição das fórmulas infantis testadas, em comparação às principais alegações descritas no rótulo e da literatura. As proposições sugeridas foram confirmadas pelo comportamento das amostras destas frente à Análise dos Componentes Principais (PCA), e a partir disto, pode-se dizer que a espectroscopia FT-MIR-ATR foi capaz de caracterizar as diferentes formulações testadas, quando aliada a estatística multivariada. Já em relação à Regressão por Mínimos Quadrados Parciais (PLS), somente foi encontrada correlação entre os dados físico-químicos e os espectros MIR no intervalo entre 1400 cm-1 e 1000cm-1, e por isso, este foi utilizado para as previsões dos valores analíticos. Por ser a região característica da absorção de carboidratos, o modelo apresentou os melhores resultados na predição do teor deste componente, com perfil de curva de calibração e ao mesmo tempo, apresentou predições ruins para o restante dos atributos testados. Sugere-se que o modelo possui potencial para as predições físico-químicas, em especial para carboidratos, caso sejam efetuadas curvas de calibração para este tipo de matriz alimentar. / This work focuses on the use of Fourier Transformed Mid Infrared Spectroscopy (FT-MIR) coupled to Attenuated Total Reflectance (ATR), combined with multivariate calibration as Principal Component Analysis (PCA) and Partial Least Squares (PLS) to characterize and quantify the majority composition of infant formulas. Twenty trademarks marketed in Juiz de Fora (MG) were evaluated from four different industries. The majority composition of the samples (lipid content, true protein, carbohydrates, moisture, total solids and ashes) was determined by physicochemical methods, in duplicate, according to official analysis methodologies. The results, in general, comply with current legislation. On the other hand, the spectroscopic evaluation of the formulations was performed in the MIR region from 4000 cm-1 to 400 cm-1. Using statistical tools, it was possible to interpret the generated spectra and characterize the composition of the infant formulas tested, in comparison to the main claims described in the labels and in the literature. The suggested propositions were confirmed by the behavior of these samples when compared to PCA. It can be said that FT-MIR-ATR spectroscopy was able to characterize the different formulations tested, when allied to multivariate statistics. In relation to the Regression by PLS, only a correlation was found between physicochemical data and MIR spectra in the interval between 1400 cm-1 and 1000 cm-1, and therefore, it was used for the predictions of the analytical values. Because it is the characteristic region of carbohydrate absorption, the model presented the best results in the prediction of the content of this component, with a calibration curve profile and at the same time presented bad predictions for the rest of the attributes tested. It is suggested that the model has potential for physicochemical predictions, especially for carbohydrates, if calibration curves are made for this type of food matrix.

Ce mémoire rapporte les études de protéines amyloïdes en interaction avec des membranes modèle afin d’établir une relation structure toxicité. Nous avons choisi différents modèles membranaires (monocouches, bicouches) de composition lipidique et charges différentes et utilisé différentes méthodes physico-chimiques afin de caractériser les interactions des protéines amyloïdes avec les membranes.Nous avons montré l’importance de la contribution électrostatique dans les interactions de la protéine amyloïde HET-s (218-289) et ses mutants avec les membranes modèles.L’ellipsométrie a démontré que les mutants toxiques de HET-s (218-289) (M8, WT.Y1Y2V2) perturbentfortement les monocouches lipidiques à l’interface air-eau. La structure riche en feuillets β antiparallèles des protéines àl’interface air-eau et dans l’interaction avec les monocouches de lipides a été démontrée par la spectroscopie PMIRRAS (Polarization Modulation – Infrared Reflection Absorption Spectroscopy). Nous avons établie que l’interface air-eau peut modifier l’agrégation des protéines amyloïdes. A l’aide de la spectroscopie de fluorescence, la spectroscopie PWR (Plasmon-Waveguided Resonance) et la spectroscopie ATR-FTIR (Attenuated Total Reflection – Fourier Transform Infrared), nous avons mis en évidence que la protéine toxique M8 adopte une structure riche en feuillets β antiparallèles en altérant fortement l’intégrité des bicouches lipidiques. Au contraire, la protéine non toxique WT se structure en feuillets β parallèles dans ces interactions et elle ne perturbe pas l’homogénéité des membranes. La toxicité de la protéine M8 semble liée à son organisation différente et à sa capacité à réorganiser les membranes.Nos résultats confortent également l’hypothèse de la toxicité des oligomères amyloïdes.Une étude sur la fabrication d’une cellule microfluidique pour la séparation de différents types d’autoassemblage afin de les détecter et de les étudier en interaction avec des liposomes par spectroscopie infrarouge est présentée. Une cellule microfluidique de CaF2 de 8 μm d’épaisseur de canaux est obtenue et est utilisée pour la détection d’une protéine de test. / This manuscript reports the studies of amyloid proteins in interaction with membrane models in order to establish their structure-toxicity relationship.Membrane models (monolayer, bilayer) of different charge and lipid composition were used. We used various physico chemical methods to characterize the interaction of these amyloid proteins with membranes.We showed the importance of the electrostatic contribution in the interactions of the amyloid protein HET-s(218-289) and its mutants with model membranes.Ellipsometry showed that the toxic mutants of HET-s (218-289) (M8, WT.Y1Y2V2) strongly disturbed thelipid monolayers at the air-water interface. The structure rich in antiparallel β sheets of auto-assembled proteins at theair-water interface and in interaction with lipid monolayers at the air-water interface has been demonstrated by the PMIRRAS spectroscopy (Polarization Modulation - Infrared Reflection Absorption Spectroscopy). We established that theair-water interface can change the aggregation properties of amyloid proteins.By using fluorescence spectroscopy, PWR spectroscopy (Plasmon Resonance-Waveguided spectroscopy) and ATR-FTIR spectroscopy (Attenuated Total Reflection - Fourier Transform Infrared spectroscopy), we found that thetoxic protein (M8) adopted a structure rich in antiparallel β sheets greatly altered the integrity of lipid bilayers. Incontrast, the protein non-toxic (WT) organized in a structure rich in parallel β sheets in these interactions and it did notdisturb the homogeneity of the membranes. The toxicity of the protein M8 appears to be related to its differentorganization and its ability to rearrange membranes.Our results also support the hypothesis of the toxicity of amyloid oligomers.A study on the fabrication of a microfluidic cell for the separation of different aggregation states of amyloidproteins in order to detect these assemblies and to study their interaction with liposomes by infrared spectroscopy is presented. A CaF2 microfluidic cell with channels of 8 μm of thickness was obtained and was used for the detection of atested protein.

Uran kann sowohl durch geogene als auch anthropogene Vorgänge in die Umwelt gelangen. Dazu zählen natürliche Uranerzvorkommen und deren Leaching sowie die Auswaschung von Uran aus den Hinterlassenschaften des ehemaligen Uranerzbergbaus. Die Aufklärung des Verhaltens von Uran in der Geo- und Biosphäre ist für eine Risikoabschätzung des Migrationsverhaltens von Radionukliden in der Umwelt notwendig. Algen sind in der Natur weit verbreitet und die wichtigste Organismengruppe in den aquatischen Lebensräumen. Durch ihre ubiquitäre Verbreitung in der Natur ist ihr Einfluss auf das Migrationsverhalten von Uran in der Umwelt von grundlegendem Interesse z.B. um effektive und wirtschaftliche Remediationsstrategien für Wässer zu entwickeln. Außerdem stehen Algen am Beginn der Nahrungskette und spielen eine wirtschaftlich relevante Rolle als Nahrung beziehungsweise Nahrungsergänzungsmittel. Die Möglichkeit des Transfers von algengebundenem Uran entlang der Nahrungskette könnte eine ernsthafte Gesundheitsgefahr für den Menschen darstellen. Das Ziel dieser Arbeit war die quantitative und strukturelle Charakterisierung der Wechselwirkung zwischen Uran(VI) und der Grünalge Chlorella vulgaris im umweltrelevanten Konzentrations- und pH-Wertbereich unter besonderer Berücksichtigung der Stoffwechselaktivität. Die in dieser Arbeit erzielten Ergebnisse der Sorptionsexperimente zeigen deutlich den maßgeblichen Einfluss des Stoffwechselstatus von Chlorella auf die Wechselwirkung mit Uran. So kann in Gegenwart von umweltrelevanten Urankonzentrationen eine Remobilisierung von zuvor passiv gebundenem Uran durch die stoffwechselaktiven Algen erfolgen. Die in Abhängigkeit von der Stoffwechselaktivität, der Urankonzentration und dem pH-Wert mit den Algenzellen gebildeten Uran(VI)-Komplexe wurden strukturell mit Hilfe der spektroskopischen Methoden TRLF-, EXAFS- und ATR-FTIR-Spektroskopie charakterisiert. Mittels TEM konnte Uran in Form von 30-70 nm großen nadelförmigen Ablagerungen in der Zellwand der lebende Algenzellen nachgewiesen werden. Die in dieser Arbeit erhaltenen Ergebnisse leisten einen wichtigen Beitrag zur Vorhersage des Migrationsverhaltens von Uran unter umweltrelevanten Bedingungen und der radiologischen Risikobewertung von geogen und anthropogen auftretendem Uran. / Uranium could be released into the environment from geogenic deposits and from former mining and milling areas by weathering and anthropogenic activities. The elucidation of uranium behavior in geo- and biosphere is necessary for a reliable risk assessment of radionuclide migration in the environment. Algae are widespread in nature and the most important group of organisms in the aquatic habitat. Because of their ubiquitous occurrence in nature the influence of algae on the migration process of uranium in the environment is of fundamental interest e.g. for the development of effective and economical remediation strategies for contaminated waters. Besides, algae are standing at the beginning of the food chain and play an economically relevant role as food and food additive. Therefore the transfer of algae-bound uranium along the food chain could arise to a serious threat to human health. Aim of this work was the quantitative and structural characterization of the interaction between U(VI) and the green alga Chlorella vulgaris in environmental relevant concentration and pH range with special emphasis on metabolic activity. The obtained findings of the sorption experiments in this study demonstrate clearly, the interactions with uranium are heavily influenced by the status of the investigated Chlorella cells. So in presence of environmentally relevant uranium concentrations a remobilization of algal-bound uranium by metabolically active algae occurred. The U(VI)-algae-complexes formed in dependence of cell activity, uranium concentration and pH value were structural characterized by TRLF, EXAFS and ATR-FTIR spectroscopy. With the help of TEM under the given experimental conditions uranium was detected in form of 30-70 nm needle-like deposites in the cell wall of living algae. The obtained results of this study contribute to the prediction of the migration behavior of uranium under environmental conditions, the radiological risk assessment of geogenic and anthropogenic appearing uranium and a reliable estimation of the accumulation of uranium in the food chain.