La peau est l’organe le plus étendu du corps humain. Doté d’une membrane biologique fine appelée la couche cornée, celle-ci le protège du desséchement et des agressions extérieures chimiques ou mécaniques auxquelles le corps humain doit faire face. Ce travail de thèse a consisté, dans un premier temps, à décrire via la littérature existante les effets de l’âge,dûs au vieillissement intrinsèque et extrinsèque,sur la physiologie cutanée du Stratum Corneum (SC).La partie expérimentale basée sur la microscopie vibrationnelle traitera des variations de la fonction barrière et de l’hydratation du SC lors du vieillissement chronologique et photo-vieillissement. D’autres méthodes ont également été utilisées comme la chromatographie liquide en phase normale couplée à la spectrométrie de masse haute résolution dotée d’une source APCI et d’un détecteur Orbitrap pour l’étude de la composition détaillée des lipides du SC ainsi que des méthodes plus globales comme la PIE ou la cornéométrie. Le caractère non invasif de toutes ces méthodes a permis de réaliser ces études in vivo. L’évolution de la fonction barrière a été étudiée aux niveaux tissulaire, moléculaire et supramoléculaire par micro-spectroscopie confocale Raman et spectroscopie Infrarouge. Puis le lien moléculaire a été fait entre le vieillissement intrinsèque et les céramides de la matrice lipidique intercornéocytaires par chromatographie en phase liquide couplée à la spectrométrie de masse. Les molécules discriminantes entre population jeune et âgée ont été déterminées par analyse chimiométrique. L’évolution de l’hydratation cutanée aux niveaux tissulaire, moléculaire et supramoléculaire a également été l’objet d’une investigation approfondie. Les variations de la composition des NMF et la teneur en eau dans le SC lors du vieillissement cutané ont été mises en lumière en utilisant des descripteurs spectraux Raman. Les variations structurelles des molécules d’eau impactant l’organisation supramoléculaire des édifices lipidiques ont également été évaluées. Au cours du vieillissement, la fonction barrière cutanée et hydratation sont conservées. / Skin is the external surface defining the human body in space. Its outer-most layer is a thin biological membrane, called Stratum Corneum(SC), that protects the internal organs from desiccation as well as chemical or mechanical external aggressions. The present thesis aimsin a first step, to summarize the current knowledge regarding the effects of intrinsic and extrinsic aging on SCphysiology,based on available literature. The experimental part addresses the gaps in our understanding of the effects of chronological aging and photoaging on the SC barrier function and hydration, using traditional methods (such as trans epidermal water loss and skin conductance) as well as more advanced ones (vibrational spectroscopies, liquid chromatography in normal phase tandem mass spectrometry high resolution with an APCI source and an Orbitrap detector. As these methods are non-invasive, all studies have been carried out in vivo. The evolution of the barrier function has been studied at the tissular, molecular and supramolecular levels using confocal Raman micro-spectroscopy and infrared spectroscopy. Then the link between the intrinsic aging and the ceramides of the intercorneocytary lipid matrix has been studied by liquid chromatography tandem mass spectrometry. The discriminant molecules between young and old population have been identified by a chemometric analysis. The evolution of cutaneous hydration at the tissular, molecular and supramolecular level has also been investigated. The variations in the NMF composition and the SC water content have been studied by Raman spectral descriptors. Moreover, the structural variations of water molecules impacting the supramolecular organization of the lipid structures have been evaluated. Chronological aging and chronic exposure to environmental factors mildly affect SC barrier function and hydration levels. However, the processes controlling these properties are affected by aging in a site-dependent fashion.

Les glicosidases que hidrolitzen els substrats amb retenció de configuració segueixen un mecanisme general en què després d'una primera etapa d'associació enzim-lligand s'encadenen dues etapes catalítiques que porten a la hidròlisi del substrat conservant la configuració del carboni anomèric en el nou extrem generat. En el present treball es comprova a través d'estudis mecanístics, principalment estudis en estat preestacionari i anàlisis de Hammett, que amb aquest mecanisme tan senzill no es pot descriure correctament l'activitat catalítica de la 1,3-1,4-β-glucanasa de Bacillus licheniformis, i es proposa el mecanisme que es mostra a continuació: on els complexos enzim-substrat adopten dues conformacions productives (SES* i SES**) i on el balanç entre aquestes dues conformacions en funció del substrat explica els diferents comportaments cinètics en estat estacionari i preestacionari.Un estudi en profunditat sobre la importància que exerceix la interacció entre l'enzim i l'hidroxil a C2 de la unitat de glucopiranosa que ocupa el subseti -1 demostra que en el cas de la 1,3-1,4-β-glucanasa de Bacillus licheniformis aquesta interacció no juga el paper rellevant que s'ha observat en altres β-glicosidases que actuen amb retenció de configuració.L'estudi de la reacció d'hidratació del glical G4G3G' catalitzada per la 1,3-1,4-β-glucanasa de Bacillus licheniformis permet proposar que hi ha un canvi en el residu que fa el paper d'àcid general. De manera que es proposa que l'Asp136 que en la reacció d'hidròlisi de substrats ajuda al posicionament dels residus catalítics i juga un paper en la regulació dels seus pKa, és el residu que fa d'àcid general en la reacció d'hidratació de glicals. / Las glicosidasas que hidrolizan substratos con retención de configuración siguen un mecanismo general en que después de una primera etapa de asociación enzima-ligando se encadenan dos etapas catalíticas que llevan a la hidrólisis del substrato conservando la configuración del carbono anomérico en el nuevo extremo generado. En el presente trabajo se comprueba a través de estudios mecanísticos, principalmente estudios en estado pre-estacionario y análisis de Hammett, que con este mecanismo tan sencillo no se puede describir correctamente la actividad catalítica de la 1,3-1,4-β-glucanasa de Bacillus licheniformis, y se propone el mecanismo que se muestra a continuación: donde los complejos enzima-substrato adoptan dos conformaciones productivas (SES* y SES**) y donde el balance entre estas dos conformaciones en función del substrato explica los diferentes comportamientos cinéticos en estado estacionario y pre-estacionario.Un estudio en profundidad sobre la importancia que ejerce la interacción entre el enzima y el hidroxilo en C2 de la unidad de glucopiranosa que ocupa el subsitio -1 demuestra que en el caso de la 1,3-1,4-β-glucanasa de Bacillus licheniformis esta interacción no juega el papel relevante que se ha observado en otras β-glicosidasas que actuan con retención de configuración.El estudio de la reacción de hidratación del glical G4G3G' catalizada por la 1,3-1,4-β-glucanasa de Bacillus licheniformis permite proponer que hay un cambio en el residu que ejerce el papel de ácido general. De manera que se propone que el Asp136 que en la reacción de hidrólisis de substratos ayuda en el posicionamiento de los resíduos catalíticos y juega un papel en la regulación de sus pKa, es el resíduo que actúa de ácido general en la reacción de hidratación de glicales. / Retaining glycosidases follow a general mechanism in which the first enzime-ligand association is followed by two catalytic steps that render the product of hydrolysis with the same anomeric configuration as the starting material. In the present work we demonstrate using mechanistic studies, basically pre-steady state kinetics and Hammett analysis, that this mechanism is too simple to properly describe the catalytic activity of Bacillus licheniformis 1,3-1,4-β-glucanase, and the following mechanism is proposed: In this mechanism, the enzim-substrate complexes adopt two productive conformations (SES* and SES**) and the balance between these two conformations depending on the nature of the substrate explains the diferent behaviours observed in pre-steady and steady state kinetics.A deep study on the importance of the interaction between the enzyme and the hydroxyl group at C2 of the glucopyranose residue that occupies the -1 subsite demonstrates that in Bacillus licheniformis 1,3-1,4-β-glucanase this interaction is not the key interaction observed in other retaining β-glycosidases.The study of the G4G3G' glical hydration catalysed by the Bacillus licheniformis 1,3-1,4-β-glucanase let us propose that there is a change in the residue that acts as a general acid. We propose that Asp136, that plays a role positioning the catalytic residues and modulating their pKa in the hydrolysis reaction, acts as the general acid in the hydration of glycals.

No description available.

Living cells accumulate compensatory solutes for protection against the harmful effects of extreme environmental conditions such as high salinity, temperature and desiccation. Even at high concentrations these solutes do not disrupt the normal cellular functions and at times counteract by stabilizing the cellular components. These properties of compensatory solutes have been exploited for stabilizing proteins and cells in vitro. Betaines are widespread natural compensatory solutes that have also been used in other applications such as therapeutic agents and polymerase chain reaction (PCR) enhancers. Some biomedical applications of novel synthetic analogues of natural betaines were investigated. Natural compensatory solutes are either dipolar zwitterionic compounds or polyhydroxyl compounds, and the physical basis of compensation may differ between these, so one focus was on synthetic betaines with hydroxyl substituents. The majority of the synthetic solutes stabilized different model proteins against stress factors such as high and low temperatures. The presence of hydroxyl groups improved protection against desiccation. The observed stabilization effect is not just on the catalytic activity of the enzyme, but also on its structural conformation. Synthetic compensatory solutes have a potential application as protein stabilizers. Dimethylthetin was evaluated as a therapeutic agent and found to be harmful in a sheep model. However, from the study we were able to generate a large-animal continuous ambulatory peritoneal dialysis (CAPD) model and showed that glycine betaine could be added to the dialysis fluid in chronic renal failure. Some synthetic compensatory solutes reduce the melting temperatures of DNA better than most natural solutes. Synthetic solutes were identified that have potential to enhance PCR and could replace some reagents marketed by commercial suppliers. Density, viscosity and molecular model data on the solutes showed correlations with the biochemical effects of the solutes, but no physical measurements were found that reliably predicted their potential for biotechnological applications.

台灣高齡者之吞嚥困難解決方案的市場分析與商機 / It has been suggested that dysphagia affects approximately 8 % of the world’s population. People may be completely unable to swallow or may have trouble in safely swallowing liquids, foods, or saliva. When that happens, eating becomes a challenge. Recent studies have identified elderly people who require the long- term care as being at increased risk for dysphagia due to changes in the swallowing mechanism as aging occurs, it may affect 30% to 40% of the population at 65 years old or more. Taiwan is on course to go from being an “aging society” to an “aged society” and is experiencing a rapid increase in the number of older adults who require long-term care. Dysphagia is a prevalent difficulty among elderly people. Though increasing age facilitates subtle physiological changes in the swallow function, age-related diseases are significant factors in the presence and severity of dysphagia. Among elderly diseases and health complications, stroke and dementia reflect high rates of dysphagia. In both conditions, dysphagia is associated with nutritional deficits and increased risk of pneumonia. Recent efforts have suggested that long-term care organizations or nursing homes are also at risk for dysphagia and are associated deficits in nutritional status and increased pneumonia risk. Swallowing rehabilitation is an effective approach to increase safe oral intake in these populations and recent research has demonstrated extended benefits related to improved nutritional status and reduced pneumonia rates. Living with dysphagia is challenging, but it can be managed. For elderly people with dysphagia, it's important to continue the principle of maintaining hydration, calories and nutrients, especially protein and fluids. Texture-modified foods and thickened liquids can help achieve nutritional and hydration goals. This research provides the market analysis of dysphagia solution and its market opportunities in Taiwan. It concludes with a market plan to assess the viability of such a business opportunity. Well- structured management of dysphagia can not only provide elderly people’s physical, mental and social well-being but also brings the elderly people the pleasures of eating and the dignity during the last few years of their lives.

Previous studies of short DNA hairpins have revealed that loop and stem sequences can significantly affect the thermodynamic stability of short DNA hairpins. Nevertheless, there has not been sufficient investigation into the pressure-temperature stability of DNA hairpins, and the current thermodynamic knowledge of DNA hairpins’ stability is limited to the temperature domain. In this work, we report the effect of hydrostatic pressure on the helix-coil transition temperature (TM) for eleven short DNA hairpins at different salt concentrations by performing UV-monitored melting. The studied hairpins form by intramolecular folding of 16-base self-complementary DNA oligo¬deoxy¬ribonucleotides. Model dependent (van’t Hoff) transition parameters such as ΔHvH and transition volume (ΔV) were estimated from analysis of optical melting transitions. Experiments revealed the ΔV for denaturation of these molecules range from -2.35 to +6.74 cm3mol-1. The difference in the volume change for this transition is related to differences in the hydration of these molecules.

Previous studies of short DNA hairpins have revealed that loop and stem sequences can significantly affect the thermodynamic stability of short DNA hairpins. Nevertheless, there has not been sufficient investigation into the pressure-temperature stability of DNA hairpins, and the current thermodynamic knowledge of DNA hairpins’ stability is limited to the temperature domain. In this work, we report the effect of hydrostatic pressure on the helix-coil transition temperature (TM) for eleven short DNA hairpins at different salt concentrations by performing UV-monitored melting. The studied hairpins form by intramolecular folding of 16-base self-complementary DNA oligo¬deoxy¬ribonucleotides. Model dependent (van’t Hoff) transition parameters such as ΔHvH and transition volume (ΔV) were estimated from analysis of optical melting transitions. Experiments revealed the ΔV for denaturation of these molecules range from -2.35 to +6.74 cm3mol-1. The difference in the volume change for this transition is related to differences in the hydration of these molecules.

Le ciment Portland est de loin le liant hydraulique le plus connu et utilisé depuis de très nombreuses années tant dans le secteur de la construction civile qu’au niveau du stockage des déchets (barrières ouvragées ou matériau de confinement). Le processus industriel qui donne naissance au clinker, constituant de base du ciment Portland, n’a pas subi de modifications depuis des décennies. <p>Par ailleurs, au cours de ces dernières années, certaines considérations telles que le réchauffement climatique et le développement durable ont mis à mal les industries qui émettent des gaz à effets de serre et qui sont grosses consommatrices d’énergie. <p>Or, la production de ciment Portland n’est pas uniquement consommatrice de calcaires, d’argiles, de marnes et de combustibles fossiles, elle produit et libère ces gaz à effets de serre tels que le dioxyde de carbone (CO2) et l’hémioxyde nitreux (N2O). Le dioxyde de soufre (SO2), l’acide chlorhydrique (HCl) ainsi que d’autres oxydes d’azote (NOx) sont également émis lors du processus de fabrication du clinker. Le secteur des matériaux de construction contribue de façon importante aux émissions de CO2, le principal responsable du réchauffement climatique.<p>La problématique majeure de l’industrie cimentière provient d’un simple processus chimique de transformation :la décarbonatation du calcaire ou de la craie, débutant vers 550°C, qui forme de la chaux (CaO) et qui libère du dioxyde de carbone selon la réaction suivante :<p><p>CaCO3 =\ / Doctorat en sciences, Spécialisation géologie / info:eu-repo/semantics/nonPublished

This doctoral thesis is focused on the possibilities of alkali-activated slag (AAS) shrinkage reduction, which would together with the use of waste sludge from waterglass production contribute to wider practical utilization of this interesting material. Besides the influence on AAS dimensional changes also effect of various factors on workability, setting time and mechanical properties was investigated. Obtained results were supported by the application of instrumental techniques like izotermal calorimetry, mercury intrusion porosimetry, scanning electron microscopy and X-ray diffraction. The results show the possibilities of reduction of AAS drying shrinkage related to its cracking tendency through the combination of increased dose of waterglass and reduced water to slag ratio (w/b), partial replacement of slag by pulverized fly ash or cement by-pass dust and application of organic admixtures, where significant effect on AAS hydration was observed. On the basis of the obtained results concrete mixtures, where the whole activator was replaced by the waste sludge form waterglass production, were designed and optimized in terms of shrinkage, mechanical properties and price. Selected concretes were also tested in semi-operating conditions.

This work is devoted to study the influence of the composition on mechanical properties of high performance concret based on portland cement. 29 samples of high performance concrete (HPC) warying in composition were prepared. The constituents used for HPC preparation were: cement Aalborg White, silica fume, finelly ground blast furnace slag, finelly ground silica, calcinated bauxite and polycarboxylate based superplasticizer. The mechanical parameters (flexural and compressive strength) of the samples were observed after 7 and 28 days of moist curing. Compressive strength values after 28 days were in the range of 92 to 194 MPa and the flexural strength values were in the range of 7 to 23 MPa (without using of fiber reinforcement). The graphs showing mechanical parameters depending on the mixture composition were constructed and consequently evaluated.