La laine de verre est un matériau utilisé pour l'isolation acoustique et thermique des habitations. Ce matériau est constitué à 95% de fibres de verre et à 5% d'un liant. Bien que ce dernier soit utilisé en quantité très faible dans la formulation du matériau, il est responsable de l'obtention de bonnes propriétés mécaniques en assurant, notamment, l'intégrité structurelle du panneau de laine de verre. Pour préparer ces liants, une résine et des additifs (huile, silicone et silane) sont utilisés. Depuis une cinquantaine d'années, les résines majoritairement utilisées pour la préparation de liant pour la fabrication de la laine de verre sont de type formo-phénolique. Bien que les propriétés mécaniques des panneaux de laine de verre obtenus avec cette résine soient bonnes, il a été nécessaire d'éliminer le formaldéhyde, composé Cancérigène-Mutagène-Reprotoxique, de la formulation. C'est pourquoi de nouvelles résines ont dû être développées. Ces développements ont permis de retenir une résine pH-compatible à base de saccharose et avec des propriétés mécaniques analogues à celles obtenues avec la résine formo-phénolique. Le but de cette thèse est donc d'accéder à une connaissance approfondie des mécanismes réactionnels mis en jeu dans la formation de cette résine pour pouvoir, in fine, en optimiser ses performances / Glass wool is a material used for the acoustic and thermal insulation of dwellings. This material contains 95% of glass fibers and 5% of binder. Although this binder is used in a very small quantity in the formulation, it provides the expected mechanical properties by ensuring the structural integrity of the glass wool panel. To prepare these binders, resin and additives (oil, silicone and silane) are used. For fifty years the resins mostly used for the preparation of glass wool’s binders were the formo-phenolic’s types. Although theses resins provide good mechanical properties of the glass wool panels, it was necessary to remove the formaldehyde, a Carcinogen-Mutagen-Reprotoxic compound, from the formulation. As a consequence, new resins were developed. These developments helped us to retain a pH-compatible resin based on sucrose with mechanical properties as good as formo-phenolic’s resin. So, the aim of this thesis is to investigate the whole chemistry’s mechanism involved in the formation of this resin in order to be able to increase its performance

Purpose. 5-HMF is a potential antisickling agent forming a Schiff-adduct with hemoglobin (Hb). In-vitro studies were designed to identify the metabolic pathways of 5-HMF in human hepatic cytosol, to assess inter-species differences in its hepatic metabolism, and to predict in-vivo PK properties. Moreover, metabolism of 5-HMF in human RBCs was investigated. Finally, in-vitro studies were done to characterize 5-HMF binding kinetics with human Hb and albumin (HSA). Methods. NAD+ reduction was monitored at 340 nm in human hepatic cytosol for 5-HMF (26 mM) and prototypical ADH and ALDH substrates in the presence or absence of their inhibitors. Furthermore, concentration-dependency studies were performed for 5-HMF (1.5-96 mM) in mouse, rat, dog, and human hepatic cytosol and fitted by Michaelis Menten (MM) model. In-vitro-in-vivo-extrapolation (IVIVE) was performed using the well-stirred model. Moreover, metabolic studies of 5-HMF (12-142 mM) in human RBCs were done under similar conditions. Time- and concentration-dependent binding studies were conducted for 5-HMF (5 µM-5 mM), in Hb (217 μM) and HSA (63 and 202 μM) solutions. Ultrafiltered 5-HMF concentrations were measured by a validated HPLC-UV assay. After correction for nonspecific binding, rate constants, binding affinity, and capacity were estimated by nonlinear regression. Results. In human hepatic cytosol, 5-HMF followed MM kinetics with Km: 218(±74) mM and was mainly inhibited by the ALDH inhibitor. In all animal species, 5-HMF exhibited millimolar Km values and is expected to have low hepatic extraction, high oral bioavailability, and first-order PK for relevant blood concentrations. The IVIVE-predicted in-vivo half-lives for 5-HMF were adequate for the mouse and dog but overestimated for humans. In RBCs, 5-HMF had Clintin-vitro of 0.34(± 0.02) ml/min/ml RBCs scaled-up to 9.9 ml/min/kg. Time-dependent binding of 5-HMF was demonstrated for both Hb and HSA. Steady-state studies revealed saturable Hb binding and non-saturable HSA binding. Conclusions. 5-HMF is an ALDH/ADH substrate in hepatic cytosol. Across animal species, 5-HMF is expected to be a low-hepatic-extraction-ratio drug with high oral bioavailability. 5-HMF is subject to RBCs metabolism in human. 5-HMF is expected to show fast association with, but slow dissociation from its drug target, Hb, which may lead to a prolonged in-vivo PD effect.

No description available.

La présence d'interactions à longue portée induit des propriétés très particulières~: énergie non additive, dynamique cohérente à l'échelle du système entier... Ces propriétés spécifiques ne dépendent pas de la nature de l'interaction à longue portée, qui peut avoir une origine variée (gravitationnelle, Coulombienne non écrantée, interaction entre vortex en turbulence 2D, couplage ondes-particules...); le but de cette thèse est d'explorer l'universalité des comportements de ces systèmes avec interactions à longue portée. Nous partons donc de modèles jouets simples, pour dégager des méthodes et résultats généraux. Nous étudions d'abord la mécanique statistique d'équilibre, dont certaines anomalies sont connues~: chaleur specifique négative, ensembles statistiques inéquivalents par exemple. Nous montrons la présence de ces anomalies sur l'exemple d'un modèle de spins champ moyen exactement soluble, autour d'un point tricritique. Nous décrivons ensuite une méthode générale fondée sur la théorie des grandes déviations pour résoudre la mécanique statistique des systèmes à longue portée, dans les ensembles canonique et microcanonique, et nous l'appliquons à plusieurs systèmes dont la solution microcanonique était jusqu'ici inaccessible. A partir de ces résultats, nous classifions les différentes situations possibles d'inéquivalence entre les ensembles. Puis nous nous intéressons à la dynamique hors équilibre des systèmes avec interactions à longue portée~: nous étudions en détail un exemple de formation de structures, et nous présentons et illustrons un scénario général de la relaxation lente vers l'équilibre, fondé sur le lien étroit avec l'équation de Vlasov. Enfin, nous appliquons les idées et méthodes mises en évidence à un modèle simple de laser à électrons libres, ce qui fournit une approche originale, complémentaire à l'étude habituelle purement dynamique de ce type de lasers.

When food is heated, a vast number of compounds are formed. Some of these are known to be toxic. Among these are furan, HMF, PhIP, IQ, and MeIQx, the subjects of this thesis. All these compounds are known or suspected carcinogens but the detailed mechanisms behind their carcinogenicity have not yet been fully examined. The aim of this thesis was to study genotoxic properties of these compounds using both in vitro and in vivo methods. Clastogenic effects of all five compounds were assessed with the flow cytometer-based micronucleus assay in vivo and for furan also with the micronucleus assay in vitro. DNA-damaging effects of HMF were studied using the comet assay. No induction of micronuclei was obtained after exposure to IQ, MeIQx or furan. Hence, it can be argued that non-genotoxic mechanisms are partly responsible for the carcinogenic properties of these compounds. PhIP, on the other hand, generated a clear response in the in vivo test. Comparing these result with previous results on acrylamide indicates that PhIP is much more potent. However, acrylamide probably poses a higher risk for humans as the intake is considerably higher. For HMF no effects were seen using the in vivo setup. To further investigate the influence of bioactivation of HMF by sulfotransferases (SULTs) the comet assay was performed in cell lines expressing different levels of SULT. However, no correlation between SULT-expression and DNA-damage was observed. Thus, the DNA-damaging effects found in our experimental setup is probably due to other factors than SULT mediated effects. Furthermore, in this thesis the effects of folic acid on chromosomal stability in healthy people were studied. A negative correlation was found between micronucleus frequency and folate status. The results gained within this thesis will hopefully contribute to the risk assessment of compounds present in our diet.

Effect of high hydrostatic pressure (150-200-250 MPa) on the microbial load and quality parameters (pH, color, 5-hydroxymethylfurfural-HMF) of white (Sultaniye) and red (Alicante Bouschet) grape juices with combination of temperature (20-30-40&deg / C) and holding time (5-10-15 min) was studied. Increased pressure and temperature showed significant effect on microbial reduction in white and red grape juices (p&lt / 0.05). The effect of pressure and time on pH drop was found to be insignificant (p&gt / 0.05). HHP resulted in E&lt / 1 for white grape and E&lt / 7 for red grape juice samples. Shelf life analysis for HHP treated white grape juice (200 MPa-40&deg / C-10min) and red grape juice (250 MPa-40&deg / C-10min) revealed no microbial growth up to 90 days when stored at 25&deg / C. Although HMF formation was observed in industrially manufactured, pasteurized samples (65&deg / C for 30 min), no HMF was detected in HHP treated white and red grape juices. HHP at the suggested conditions can be recommended as a better production alternative to heat treatment for white and red grape juice with respect to microbial load and studied quality parameters even at temperatures lower than required for pasteurization.

Heat treatment (around 50&deg / C) is a major step in honey filling and packaging that is applied before filtration to decrease viscosity, reduce the moisture level, to destroy yeasts, liquefy crystals and delay crystallization. As a result, formation of Hydroxy Methyl Furfural (HMF), decrease in enzymatic activity, color deterioration, decrease in viscosity and many other structural changes are observed. HMF is produced as a result of Maillard reaction and/or hexose dehydration -which is undesirable-, practically, it is found in fresh honey in low levels, and increases due to heat treatment, storage temperature, pH (acidity) and sugar concentration of honey. HMF level and diastase number are important quality parameters and shelf life indicators of honey. Alternatives of v heat treatment may be the use of ultrasound and high hydrostatic pressure (HHP) to decrease viscosity, liquefy honey and thus minimise adverse affects of heat treatment. Therefore, the aim of this study is to evaluate the effect of HHP (220-330 MPa, 50-60&deg / C, time) and ultrasound (24 kHz) on liquefaction and quality parameters (HMF, diastase number, color and viscosity) of different honey varieties (sunflower, cotton and canola) and to compare the changes with heat treated (50&deg / C and 60&deg / C, time) and untreated honey. Based on the results of the chemical and physical analysis, for HHP treatment the best treatment combination was determined as 220 MPa, 50&deg / C, 106 min. For ultrasound treatment the best treatment combinations were determined as 7 mm probe- 0.5 cycle (batch) applications. On this basis the study points out that Ultrasound and HHP can be suggested as alternative methods to traditional thermal treatment for the liquefaction of honey crystals. When compared to thermal treatment, Ultrasound is advantageous in shorter application times, slight changes in quality parameters and ease in operation. HHP treatment is also an alternative method with shorter application times and lower HMF values.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-05-10T15:07:06Z No. of bitstreams: 1 leandranataliadeoliveiraneves.pdf: 2553405 bytes, checksum: ca2d010014f08aa1f723b669f468fc96 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-06-15T18:59:47Z (GMT) No. of bitstreams: 1 leandranataliadeoliveiraneves.pdf: 2553405 bytes, checksum: ca2d010014f08aa1f723b669f468fc96 (MD5) / Made available in DSpace on 2016-06-15T18:59:47Z (GMT). No. of bitstreams: 1 leandranataliadeoliveiraneves.pdf: 2553405 bytes, checksum: ca2d010014f08aa1f723b669f468fc96 (MD5) Previous issue date: 2015-04-17 / O leite é considerado um alimento rico nutricionalmente por ser fonte de proteínas, carboidrato, vitaminas e minerais. Durante o processamento térmico do leite, reações químicas podem ocorrer gerando modificações de compostos pré-existentes ou formação de novos compostos, os quais se comportam como indicadores do tratamento térmico utilizado. O monitoramento destes indicadores em leite UHT é de grande importância uma vez que permite traçar o perfil do produto e do processo, podendo sugerir intervenções tecnológicas capazes de minimizar custos de produção bem como reduzir a ocorrência de eventuais perdas nutricionais e descaracterização do produto. O presente trabalho teve como objetivo quantificar os indicadores índice de soroproteína não desnaturada – WPNI, 5-hidroximetilfurfural – HMF e lactulose em amostras de leite UHT, com teor regular e reduzido de lactose, comercializadas no mercado nacional. Metodologias analíticas para WPNI e HMF, ambos determinados por métodos espectrofotométricos, foram implantadas e os modelos estatísticos foram ajustados. Dois métodos analíticos de separação para determinação de lactulose foram desenvolvidos e validados utilizando cromatografia líquida de alta eficiência (HPLC) com detecção por índice de refração e eletroforese capilar de zona (CZE) com detecção indireta no ultravioleta. Os resultados obtidos no teste de comparação de médias do teor de lactulose pelos métodos por HPLC e CZE indicaram não haver diferença significativa entre os métodos propostos. A média do índice de WPNI indicou que 76% das amostras em estudo são classificadas como “médio tratamento térmico”. Os índices de HMF livre e total mostraram-se capazes de discriminar amostras com teor regular e com teor reduzido de lactose. Flutuações nos índices de WPNI e HMF livre e no teor de lactulose das amostras analisadas sugeriram a ocorrência de falta de uniformidade do processamento adotado pelas indústrias nacionais processadoras de leite UHT, o que foi confirmado pelo efeito de marca sobre estes índices no produto. Verificou-se que os métodos analíticos implantados e desenvolvidos são capazes de atender à demanda de métodos de controle aptos em avaliar o processo e oferecer suporte para desenvolvimento e estudo do processamento. Os indicadores monitorados remetem a ocorrência de despadronização do perfil químico do leite UHT atualmente comercializado no mercado nacional, refletindo a necessidade de um maior controle do processamento pelas indústrias processadoras. / Milk is considered a nutritionally rich food because it is a source of protein, carbohydrate, vitamins and minerals. During milk heat treatment, chemical reactions can occur causing changes of pre-existing compounds or formation of new compounds, which can be used as indicators of heat treatment used. The monitoring of these indicators in UHT milk is very important since they allow to draw the product and process profile and can suggest technological interventions that can minimize production costs and reduce the occurrence of any nutritional losses and distortion of the product. This study aimed to quantify the indicators whey protein nitrogen index - WPNI, 5-hydroxymethylfurfural – HMF and lactulose in UHT milk samples, with regular and reduced lactose content, sold in the domestic market. Analytical methodologies for WPNI and HMF (both measured by spectrophotometric methods) were implemented and the statistical models were fitted. Two analytical methods of separation for lactulose determination were developed and validated using high performance liquid chromatography (HPLC) with detection by refractive index and capillary zone electrophoresis (CZE) with indirect UV detection. The results obtained in the mean comparison test of lactulose content by HPLC and CZE methods showed no significant difference between the proposed methods. The average WPNI index indicated that 76% of the samples studied are classified as "medium heat treatment". The contents of free and total HMF were able to discriminate samples with regular and reduced lactose content. Fluctuations in WPNI, free HMF and lactulose content of the examined samples suggested the occurrence of non-uniformity of processing adopted in processing UHT milk of national industries, which was confirmed by the effect of these indicators in the product. It was found that analytical methods studied are able to achieve the control methods demanded to evaluate the process and support the development and study of processing. The monitored indicators refer to the occurrence of lack of standardization in the chemical profile of UHT milk currently commercialized in Brazilian market, reflecting the need for greater control of processing by milk processing industries.

No description available.

Cette thèse est une exploration de l’utilisation d’aldéhydes furaniques biosourcés, tels que l’hydroxyméthyl furfural (HMF) et ses analogues, en tant que substrat pour la réaction de Morita-Baylis-Hillman (MBH). L’étendue de la réaction a été étudiée avec un focus sur la possibilité d’utiliser des milieux aqueux et biosourcés pour effectuer cette transformation. En premier lieu, l’étude a concerné la réaction de MBH du glycosyloxyméthylfurfural (GFM) avec des motifs acryliques, conduisant dans des rendements acceptables à de nouveaux glycodérivés porteurs de motifs α-hydroxyacrylates and α-méthylène-β-amino acrylates. Pour les réactions conduisant aux α-hydroxyacrylates, l’eau peut être utilisée comme solvant, de même que des mélanges d’eau et de diméthylisosorbide (DMI), remplaçant ainsi efficacement le dioxane ou le THF comparativement aux méthodes habituellement employées. Les esters acryliques de départ pouvant être eux-mêmes biosourcés, les glycoacrylates obtenus par la réaction MBH sont donc potentiellement 100% biosourcés. La version aza-MBH de la réaction a été ensuite explorée, associant 3 composants: le GMF, une sulfonamide et un accepteur de Micheal, conduisant à de nouveaux α-méthylène-b-amino carbonyl dérivatives construits sur un motif glucidique. L’étude s’est ensuite focalisée sur le HMF lui-même. Plusieurs solvants biosourcés, en particulier le 2-hydroxymethyl THF et l’isopropylidénéglycerol, se sont révélés efficaces pour la réaction de MBH du HMF avec l’acrylate d’éthyle. Pour le HMF et le furfural, la réaction est améliorée si de l’eau est ajoutée; ce qui permet d’étendre la gamme de solvants biosourcés pouvant être utilisée dans ce processus. Il a aussi été montré que l’imidazolyl alcool bicyclique DPI est un catalyseur très efficace pour la réaction MBH du HMF, du furfural ou du GMF avec des énones cycliques, conduisant à une diversité de nouvelles structures par une voie écorespectueuse et efficacement. / This thesis is an exploration of the use of biosourced furanic aldehydes, namely hydroxymethyl furfural (HMF) and analogues, as a substrate for the Morita-Baylis-Hillman (MBH) reaction. The scope of the reaction has been explored, with a focus on the possibility to perform the reaction in aqueous or biobased medium. First, the MBH reaction of the glucosyloxymethylfurfural (GMF) with acrylic building blocks has been explored, led to two new series of glycoderivatives containing α-hydroxyacrylates and α-methylene-β-amino acrylates in fair yields. For the coupling reaction which produces the α-hydroxyacrylates, water can be used as the solvent. Mixtures of water and dimethylisosorbide (DMI) have also been shown to be possibly used in the reactions, allowing replacement of dioxane or THF compared to previous methods. The strategy is atom-economical. Due to the fact that those acrylic esters are also available from biomass, such kind of glycoacrylates appears as possibly 100% bio-based. The aza-MBH version of the reaction was further explored, studying the reaction involving the three components GMF, sulfonamides and a Micheal acceptor, leading to carbohydrate-based α-methylene-β-amino carbonyl derivatives. The focus was then made on HMF itself. Several biobased solvents, in particular 2-hydroxymethyl THF and isopropylideneglycerol, could be used for the MBH reaction of HMF and ethyl acrylate. For HMF and furfural, the reaction was improved when water was added allowing to widen the range of biobased solvent systems. We have also found that the bicyclic imidazolyl alcohol DPI is an efficient catalyst for the aqueous MBH reaction between HMF, furfural, GMF, and cyclic enones that gives access to a variety of potentially very useful molecules in an efficient and environmentally friendly way.