Clays are ubiquitous near the Earth’s surface. Medicinal properties of these nontoxic minerals have been intuitively recognized since ancient times. Up till now, clays have been used in pharmaceutical formulations as active agents and excipients. Currently, there is an urgent need to seek advanced, functional materials with low environmental impact. Answering to that trend, clay-biopolymer nanocomposites were synthesized in this thesis and applied in a drug delivery system. In the first part of the thesis, Portuguese clay from a bentonite deposit in Benavila (Portugal) was collected from six sampling sites and characterized. The highest content of clay fraction, approximately 30%, was found in two of the sampling sites. After purification, the smectite-rich samples were analyzed with respect to clay content, mineralogical and chemical composition, physicochemical and mechanical properties. SEM-EDS revealed that the smectite present in the ore is montmorillonite with varying Fe content. This was also indicated by the means of XRD, XRF and FTIR. The Benavila sample, which was richest in smectite, as well as the sodium Wyoming montmorillonite from the Source Clay Repository (SWy-2) were successfully used to synthesize clay-biopolymer nanocomposites. The chosen biopolymers were the plant-extracted polysaccharides – neutral guar gum and its cationic form. The obtained materials were thoroughly characterized by XRD, TGA and NMR, and the intercalated structure was reported. The prepared nanocomposites were loaded with an anti-inflammatory drug ibuprofen and tested in an in-vitro release system. The drug-loaded materials were characterized with XRD, TGA and NMR. A membrane diffusion method was chosen as a dissolution testing strategy and the drug was quantified by UV-Vis spectroscopy. The materials exhibited improved properties as a noticeable reduction of release rate was achieved.

This thesis reports the development of a novel drug delivery system consisting of hollow nanoparticles, formed from manganese dioxide (δ-MnO2) sheets, that are coated with polydopamine and folic acid to selectively target cancer cells. The biodegradability and colloidal stability of the uncoated hollow nanoparticles were investigated in comparison to solid MnO2 nanoparticles and graphene oxide sheets. The MnO2 hollow nanoparticles degraded at a faster rate and seem to have a higher surface area and better colloidal dispersion than solid MnO2 nanoparticles. Xanthan gum was proven to improve colloidal dispersion of these hollow nanoparticles and were used for further cell studies. In this study, cancer and healthy cells were treated with coated hollow nanoparticles, and results indicate that this novel hollow nanoparticle may preferentially target and kill cancer cells. Particle aggregation has shown to be toxic to cells. Further studies with this novel drug delivery system may lead to a groundbreaking solution to targeted cancer therapy. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第18164号 / 医博第3884号 / 新制||医||1003(附属図書館) / 31022 / 京都大学大学院医学研究科医学専攻 / (主査)教授 戸口田 淳也, 教授 妻木 範行, 教授 開 祐司 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

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Soil stabilization is a widely used technique in the field of geotechnical engineering for a wide range of applications. Traditional stabilizers such as cement and lime, although very efficient, are not environmentally friendly as they leave major carbon footprints, therefore the demand for sustainable stabilization methods is escalating. This research investigates the potential of two different polymers e.g., a biopolymer derived from organic source, and an inorganic commercially manufactured polymer, as viable alternatives for soil stabilization. The current study focuses on exploring the efficacy of polymers stabilized soil in improving the engineering or geotechnical properties such as plasticity, compressibility, shear strength, and stiffness behavior.The research methodology involves using locally available high plastic clay for stabilization using two different types of polymers and performing laboratory experiments to analyze the strength parameters of the stabilized soil. Xanthan Gum (XG) is a biopolymer which is being studied is used in the percentages of 0.5%, 1.0% and 1.5% by dry weight of soil mass to understand the mechanism of biopolymer-soil interactions and to conclude optimum percentage suitable for stabilization in terms of technical and economical value. Similarly, Soiltac (ST) a vinyl copolymer inorganic polymer is used in 1.5% of dry mass of soil (optimum dosage as per previous literature) to compare its effectiveness with that of Xanthan Gum. After the determination of Atterberg limits and Optimum Moisture Content (OMC) and Maximum Dry Density (MDD), the samples were subjected to tests such as Unconfined Compressive Strength (UCS), Ultrasonic Pulse Velocity (UPV), Resilient Modulus (RM) test and Consolidation test. The prepared UCS samples were cured for 0, 7, 14, and 28 days in open air condition before performing test on them. Atterberg limits test on untreated Carbondale Soil were conducted to classify the soil as CH (Clay with high compressibility) type as per USCS (Unified Soil Classification System) classification. While tests on treated sample showed significant increasement in Liquid Limit (LL), slight increment in Plastic Limit (PL), thus quite surge in the Plasticity Index (PI) with increase in XG percentage in the soil. UCS value increased with the increase in percentage addition of XG. Also, UCS results from both untreated and polymer treated samples showed increase in compressive strength with increase in curing period. UCS value increased from 417.75 psi to 490.24 psi, 504.05 psi, and 542.91 psi for 0.5%, 1.0%, and 1.5% XG addition, respectively. This increase in UCS value was 17.35%, 20.66%, and 29.96% for the corresponding XG concentrations. The treated samples had a significant increase in the UCS for all the curing period in comparison to their respectively cured untreated sample. The percentages increase in the UCS for 1.5% XG sample in comparison to untreated sample cured for the same period is 6.45%, 59.57%, and 29.96%, respectively for 7, 14 and 28 days of curing. However, for the zero-day test, the UCS of 1.5% XG stabilized sample was found to be less than the zero-day untreated sample. With the addition of ST polymer, the UCS value increased for all the curing period while comparing with the UCS of untreated soil for the same curing period. The UCS of the ST treated soil increased from 58.56 psi to 467.367 psi when cured for 0 and 28 days which is an increase of 698.1 % i.e. 7 times the strength at 0 day. When UPV (Ultrasound Pulse Velocity) tests were compared with the UCS value for the same sample, the result showed that the higher UPV value corresponded to the higher UCS value. This relationship was supported by the high degree of correlation between the two measurements. The consolidation test showed that the Compression Index (Cc) of XG stabilized soil decreased as the percentage of XG added increased. Cc decreased from 0.2795 for pure Carbondale Soil (CS) to 0.2003 for 1.5% XG addition which is a drop of 28.33%. Likewise, Cc decreased by 3.0% and 19.33% for 0.5% and 1.0% XG doses respectively. The primary aim of this study is to simplify the understanding of the Resilient Modulus (RM) test, which yields vital data for pavement design. The efficacy of inclusion of stabilizer was further substantiated by RM testing which confirmed the enhancement of soil resilient qualities compared to the untreated soil. The RM values exhibited a growing trend, indicating an enhancement in the soil's stiffness and capacity to endure repetitive loads. This attribute is extremely important for applications such as the construction of pavements and foundations that are subjected to dynamic loads. The samples containing 1.0% XG showed significant increases in their RM values. Specifically, the RM values increased by 18.5%, 40%, and 39.5% after being cured for 7, 14, and 28 days, respectively, at a confining pressure of 6 psi. Similarly, the RM for the case of ST ranges from 15227.60 psi for 0 days of curing and 2 psi of confining stress to 45375 psi for 28 days of curing and 6 psi of confining pressure. The performance of ST against XG is higher.

Metal ions of gum arabic were removed by ion exchange to yield the free acid form. Arabate salts were prepared using monovalent and divalent metal ions. Addition of monovalent metal ions was found to double the viscosity of the gum as compared to the viscosity of the raw gum, and more than triple the viscosity of the free acid form at low solution concentration. At high solution concentration, monovalent ions increase the viscosity of the solution by about 50% over that of the raw gum. Divalent ions failed to increase the viscosity at low solution concentrations, while an increase of 14% over that of the raw gum was observed at high solution concentration. pH's were found to have a significant effect on gum viscosity. Gum arable was blended with four natural gums and one synthetic gum. The results showed that an increase in blended non-arabic gum results in greatly increased viscosity of the mixture, and that increasing gum arabic content results in viscosity reduction. Prediction of blend viscosity on the basis of the concentration of blend constituents was found to be possible, and to result in good agreement with the observed data. Studies of gum arabic trends suggested a relationship between the living conditions of the main producers and production levels. The study also concluded that incentives for quality improvement and for novel. collection and distribution methods need to be devised. The demand analysis shows an important relationship between gum demand, food- industry growth in the U.S.A., and gum price. / M.S.

O conhecimento de propriedades termofísicas é importante na modelagem, na otimização e no projeto de equipamentos para processos como a fabricação de massa de pão congelada. Neste trabalho, as propriedades termofísicas condutividade térmica, difusividade térmica e calor específico foram determinadas experimentalmente ao longo do processo de congelamento da massa de pão, pois influenciam diretamente a cinética do processo que, por sua vez, determina a qualidade do pão produzido. Os resultados obtidos mostraram que algumas destas propriedades variaram em função do conteúdo inicial de água e principalmente devido à mudança da temperatura. O valor médio encontrado através da atividade de água das massas (aw = 0,950), para temperatura inicial de congelamento, pode explicar alguns desvios no ajuste dos dados experimentais a modelos disponíveis na literatura baseados na lei de Raoult, que são estritamente relacionados à fração de gelo formada. O uso combinado de goma guar e xantana reduziu a entalpia de fusão ao longo do tempo de armazenamento congelado (87,4 J.g-1 e 81,2 J.g-1 para a formulação sem gomas, não congelada e após 28 dias de armazenamento congelado; 84,4 J.g-1 e 76,9 J.g-1 para a formulação com 0,25% de goma guar e 0,25% de goma xantana na massa não congelada e após 28 dias de armazenamento congelado), indicando uma interação entre as gomas na capacidade de ligar água ao longo do tempo de congelamento. Porém, apesar do tempo de congelamento ter reduzido a entalpia de fusão, o processo de congelamento foi o principal fator na queda da taxa de fermentação e da produção de gás pelas leveduras independentemente do tempo de armazenamento congelado. / The knowledge of thermophysical properties is important to model and optimize equipment design for frozen food processes. In this work, the thermophysical bread dough properties, such as, thermal conductivity, thermal diffusivity and specific heat were experimentally determined during freezing process, due to their influence on the kinetics process, and therefore on bread quality. The results showed that some properties varied according to the initial water content and mainly due to temperature changes. The average value of initial freezing temperature found by water activity (aw = 0.950) explains the deviations between experimental data and available models in the literature based on Raoults law, which is related to the ice mass fraction. The combined use of guar and xanthan gums reduced the fusion enthalpy along frozen storage time (87.4 J.g-1 and 81.2 J.g-1 for formulation without gum, non-frozen and after 28 frozen storage days; 84.4 J.g-1 and 76.9 J.g-1 for formulation with 0.25 % of guar gum and 0.25 % of xanthan gum in non-frozen and after 28 frozen storage days). It indicated the interaction between gums and their ability to hold water along frozen storage. Despite frozen storage reduced the fusion enthalpy, the freezing process itself was the main factor in the decrease in proofing rate and gas production by yeast cells.

O processo de microfiltração tangencial com membranas tubulares inorgânicas e tubos microporosos, respectivamente de origem importada e nacional, foi investigado tendo-se como objeto de separação as misturas macromoleculares preparadas com os agentes polissacarídeos gomas Xantana e Guar em suspensão aquosa. São evidenciados neste processo os efeitos de sinergia compreendidos nas misturas elaboradas puras e em diferentes proporções, na concentração final de 1000 ppm. A investigação experimental acompanha o comportamento reológico de cada mistura ao longo do processo e os resultados foram investigados a partir de propriedades físico-químicas relevantes como: concentração de carbono orgânico total (Total Organic Carbon - TOC) e análise de absorbância no espectômetro de infravermelho. Resultados de TOC indicaram que em apenas um meio filtrante tubular microporoso (C1T+), o desempenho do processo na retenção dos polissacarídeos foi acima de 90%, em relação ao processo com a membrana comercial importada cuja retenção de TOC foi da ordem de 80%. De acordo com as análises de absorbância, conclui-se que as membranas com tamanho do poro nominal de 0,2 \'mü\'m e 0,4 \'mü\'m tiveram uma retenção mais eficiente do que os tubos microporosos em estudo. A temperatura foi um parâmetro significativo, pois a retenção, na maioria dos casos, foi maior na temperatura de 25ºC, independente da pressão e da velocidade média. Na análise dos procedimentos envolvendo cada mistura, foi constatada a boa sinergia entre as gomas, sem modificação de estrutura (formação de gel) ou fenômenos de superfície que impedissem o processo de microfiltração. A vazão transmembrana das misturas ficou limitada entre os máximos valores para mistura pura de Xantana e mínimos para Guar. Todas as misturas apresentaram comportamento pseudoplástico, sem mudanças na reologia, reforçando a adequada sinergia quanto a este aspecto. / The present dissertation reports cross-flow microfiltration with national and imported inorganic tubular membranes and microporous tubes. The object of separation is the macromolecular mixtures prepared with polysaccharide agents Xanthan and Guar gum in aqueous solution. The process shows the synergism effects in pure and different mixture proportions, with 1000 ppm final concentration. The experiments established the rheologic behaviour of each mixture along the process and significant physical and chemical properties, such as Total Organic Carbon concentration (TOC) and absorbency analysis in infrared spectrometer were analyzed. TOC retention shows that only one microporous tubular filtering medium (C1T+) had better performance (retention 90%) than the imported commercial membrane (retention about 80%). Absorbency analysis show a better retention efficiency of membranes with pore size of 0,2 \'mü\'m and 0,4 \'mü\'m than microporous tube. The temperature was a significant parameter, as the better retention was obtained at 25ºC, independently of pressure and mean velocity. There is good synergism between Xanthan and Guar gums without structure modifications or surface phenomena that would impede the microfiltration process. The transmembrane flux of proportional mixtures has been limited between maximum values of pure Xanthan and minimum values of pure Guar mixtures. All mixtures have pseudoplastic behaviour, without changes in rheology, intensifying the good synergism.

A qualidade global da massa de pão congelada por um longo período é um desafio para indústria de panificação. O uso de diferentes técnicas pode ajudar a explicar os danos sofridos à massa de pão durante o congelamento e armazenamento congelado. A presença de água na forma de cristais de gelo foi vista como a principal causa de defeitos à estrutura da massa. Gomas guar e xantana foram incorporadas às massas para contornar os danos causados pelo congelamento. Das análises térmicas conduzidas em calorímetro de varredura diferencial foi possível quantificar a quantidade de gelo presente na massa. A adição de (0,125 a 0,250) g/100g de goma guar e de (0,214 e 0,250) g/100g de goma xantana diminuíram os valores de entalpia na massa ao longo do armazenamento congelado. A fração de gelo foi menor e mais estável nas massas contendo (0,125 e 0,250) g/100g de goma guar ou xantana. O valor da atividade de água diminuiu nas massas contendo goma guar e com níveis mais altos de goma xantana, após o ciclo de congelamento e descongelamento e 170 dias de armazenamento. Alterações na estrutura das massas foram medidas e visualizadas pela análise de textura e por microscopia eletrônica de varredura (MEV). Adição de goma xantana e principalmente de goma guar às massas aumentaram a resistência à extensão após 170 dias de armazenamento congelado. A extensibilidade não foi influenciada pela adição de gomas e manteve estabilidade nos períodos de armazenamento estudados. A MEV ajudou a explicar os danos causados à rede de glúten pelos cristais de gelo ao longo do armazenamento congelado. A massa sem gomas apareceu com pequenos danos na rede de glúten com 21 dias de armazenamento e estes danos aumentaram progressivamente por até 170 dias, mostrando um glúten menos contínuo, mais rompido e separado dos grânulos de amido. As massas contendo gomas minimizaram, mas não evitaram os danos causados ao longo do armazenamento congelado. / The global quality of the frozen bread dough for long periods of frozen storage is the challenge to bakery industry. The use of different techniques could help to explain the damages caused in the frozen dough during the freezing and along frozen storage time. The presence of water as ice crystals was the main cause of damage on the dough structure. In order to minimize the freezing damages, guar and xanthan gums were incorporated in the dough. From thermal analysis by DSC technique, the amount of ice present in the dough was determined. The addition of (0.125 to 0.250) g/100g guar gum and (0.214 and 0.250) g/100g xanthan gum presented lower values of fusion enthalpy. The addition of (0.125 and 0.250) g/100g of guar gum decreased or stabilized the frozen water content, suggesting minimal damage on the dough structure along frozen storage time. The water activity in the dough samples with guar gum and higher quantities of xanthan gum decreased after the freezing-thawed cycle and after a period of frozen storage of 170 days. The incorporation of xanthan gum and mainly the incorporation of guar gum increased the maximum resistance of the dough after 170 days. The extensibility was not affected by addition of gums along frozen storage time. The MEV technical helped to explain the damaged dough structure caused by ice crystals along frozen storage time. Dough samples without gums presented structure damage only after 21 days and increased after 170 days, resulting in less continuous gluten, more disrupted and separated from starch granules. The doughs with gums suffered less damage in the gluten matrix, but did not avoid the problems caused by frozen storage.

Milk and dairy products are one of the most prevalent and broadly consumed foodstuffs. Ice-cream occupies an important place in a wide range of dairy products. The goal of the paper. To analyze the technological process of ice-cream production in the one of the most advanced enterprise UAB Vikeda. To examine the influence of biologically valuable additives on the technological process of the ice-cream production and quality. Novelty of the paper. Samples of ice-cream have been produced under laboratory conditions of the Technology Laboratory at Lithuanian Food Institute using the following additives: wheat fiber gel Vitacel, acacia gum fiber Fibergum, lupine proteins Lupine protein and Omega-fatty acids. Physical and sensual qualities of the ice-cream have been examined. Methods of research. Research has been performed in UAB Vikeda located in Kedainiai and in Lithuanian Food Institute. The following qualities of ice-cream have been analyzed: melting of ice-cream; hardness of ice-cream; sensual evaluation of ice-cream; research of consumers. The melting of ice-cream samples has been determined in accordance with the methods presented by Lithuanian Food Institute. Instrumental research of the hardness of the ice-cream texture has been performed using the semi-automatic penetrometer Labor. Sensual qualities of ice-cream have been evaluated in accordance with the „Methods on Sensual Evaluation of Milk and Dairy Products Sensual Analysis“, worked out by Lithuanian Food Institute... [to full text]