L’entreprise SEPROSYS est une société spécialisée dans le développement de solutions d'extraction et de séparation de molécules. Au cours de l’année 2011, l’entreprise a développé un procédé innovant de séparation et de purification fractionnée de biomolécules issues de macroalgues marines. Ce travail de thèse a pour objectif de trouver des applications aux fractions extraites selon le procédé d’extraction et de purification de la société SEPROSYS, et en particulier la fraction des polysaccharides sulfatés, dans deux domaines distincts : en pharmaceutique pour leur activité anti-coagulante et en cosmétique pour leur activité anti-âge. La première partie de nos travaux se penche sur le potentiel des polysaccharides sulfatés de macroalgues comme anti-coagulants. Pour cela, des extraits aqueux de différentes macroalgues brunes, rouges et vertes ont été préparés et leur activité anti-coagulante a été mesurée. Les algues présentant le meilleur potentiel ont ensuite été traitées au moyen du procédé SEPROSYS® afin de purifier leurs polysaccharides sulfatés et d’étudier leur activité anti-coagulante. De plus, l’objectif de ce travail consiste également à mieux comprendre la relation structure-fonction de l'activité anticoagulante d'ulvanes. A cette fin, des ulvanes issus d’Ulva sp. de pureté élevée ont été produits par le procédé SEPROSYS®, soumis à des modifications chimique (hypersulfatation) et physique (dépolymérisation) et leur activité anticoagulante a été étudiée. La deuxième partie de nos travaux concerne l’évaluation du potentiel de ces macroalgues comme agents actifs utilisables en dermo-cosmétique, en particulier pour leur activité anti-âge. Dans ce but, différentes fractions de macroalgues brunes, rouges et vertes ont été testées sur des lignées cellulaires de fibroblastes dermiques humains et leur effet sur la production de collagène par ces fibroblastes a été étudié. Enfin, le potentiel d’ulvanes extraits d’Uva sp. par le procédé de l’entreprise SEPROSYS pour stimuler la biosynthèse de collagène et d’acide hyaluronique par ces mêmes fibroblastes a été déterminé. / SEPROSYS is a company specialized in the development of solutions for the extraction and separation of molecules. In 2011, the company has developed an innovative process of fractionated separation and purification of biomolecules from macroalgae. The purpose of this thesis work is to find applications for the purified fractions from the SEPROSYS® process and in particular the sulfated polysaccharides, for two distinct biological activities : as pharmaceutical for their anti-coagulant activity and as dermo-cosmetics for their anti-aging activity. The first part of our work focus on the potential of sulfated polysaccharides from macroalgae as anti-coagulant agents. To this end, aqueous extracts from brown, red and green macroalgae were prepared and their anti-coagulant activity was measured. The best macroalgae were then processed with the SEPROSYS procedure in order to purify the sulfated polysaccharides and study their activity. Furthermore, one of the objectives of this work was to acquire a better understanding of the structure/anti-coagulant function relationship of ulvans. Ulvans of high purity were extracted from Ulva sp. with the SEPROSYS® process, submitted to chemical (hypersulfatation) and physical (depolymerization) modifications and their anti-coagulant activity was measured. The second part of our work relates to the potential of the macroalgae as active agents to be used in dermo-cosmetics, and, in particular, for their anti-aging activity. Different brown, red and green macroalgae fractions were thus tested on normal human dermal fibroblasts cell lines and their effects on the collagen production were measured. Furthermore, the capacity of different molecular weight ulvans extracted from Ulva sp. to stimulate the collagen and hyaluronan biosynthesis was studied. To this end, we developed an efficient depolymerization procedure using ion exchange resins.

Resumo: Exopolissacarídeos do tipo β-glucanas são polímeros produzidos por uma grande variedade de microrganismos e podem possuir diferentes propriedades físicas, químicas e aspectos estruturais. Esses biopolímeros apresentam atividades biológicas interessantes (antitumor, antiviral, anticoagulante) e aplicações comerciais como produtos em alimentos, cosméticos e farmacêuticos. Entretanto, para a aplicação dessas moléculas, é necessário primeiramente o conhecimento de suas estruturas químicas. Assim, o objetivo deste trabalho foi a produção, caracterização química de quatro exopolissacarideos (EPSGRAVIOLA, EPSMANGA, EPSPINHA e EPSLARANJA) de isolados de Botryosphaeria obtidos de frutas tropicais em decomposição e crescidos em sacarose como única fonte de carbono, determinando o melhor EPS para realizar testes de atividade anticoagulante. A homogeneidade de cada EPS foi determinada por cromatografia de filtração em gel, os quais eluíram como um único pico. Hidrólise ácida total e análise por HPAEC/PAD mostrou glucose como constituinte básico. Dados de metilação e RMN de 13C indicaram que os EPSMANGA, EPSPINHA e EPSLARANJA são glucanas lineares unidas por ligações do tipo β(1®6) e o EPSGRAVIOLA é uma glucana com ligações β(1®3) e com ramificações em C-6 de resíduos glucopiranosídicos. O espectro de FT-IR mostrou uma banda em 891 cm-1, e a espectroscopia de 13C NMR mostrou que todas as ligações eram do tipo β. Estudos realizados com o corante Vermelho Congo indicaram que os EPS possuem conformação em tripla hélice. O EPSLARANJA, uma b- D-(1®6)-glucana, foi submetido a sulfatação visando induzir a atividade anticoagulante e melhorar a solubilidade da molécula em solução, importante para a atividade biológica. Espectros de FT-IR mostraram bandas em 808 and 1252 cm-1, indicando a entrada dos grupos sulfato e as análises de RMN de 13C mostraram... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Exopolysaccharides (EPS) as β-glucans are polymers produced by a great variety of microorganisms and can possess different physical and chemical properties, and structural features. These biopolymers having interesting biological activities (antitumor, anti-viral, anticoagulant), and commercial applications in foods, cosmetics and pharmaceutical products. However, for the applications of these macromolecules, it is first necessary to understand their chemical structures. Therefore the goal of that study was the production, chemical characterization and biological activity of four exopolysaccharides (EPSGRAVIOLA, EPSMANGO, EPSPINHA and EPSORANGE) obtained from Botryosphaeria strains isolated from rotting tropical fruit grown on sucrose as carbon and the best EPS was used for the anticoagulant activity The homogeneity of each EPS was determined by gel filtration chromatography, which was eluted as a single peak. Total acid hydrolysis and HPAEC/PAD analysis of each EPS yielded only glucose. Data from methylation analysis and 13C NMR spectroscopy indicated that the EPSMANGO, EPSPINHA and EPSORANGE consisted of a linear chain of (1-6)- linked glucopyranosyl residues and EPSGRAVIOLA consisted of a main chain of glucopyranosyl (1-3) linkages substituted at O-6. FTIR spectra showed one band at 891 cm-1, and 13C NMR spectroscopy showed that all glucosidic linkages were of the β-configuration. Dye-inclusion studies with Congo Red indicated that each EPS existed in a triple-helix conformational state. The EPSORANGE, a β-(1®6)- D-glucan was submitted to a sulfation to induce anticoagulant activity and also to make this EPS more soluble, which is in favor to its biological action. The FT-IR spectrum showed bands at 808 and 1252 cm-1 indicating insertion of sulfonyl groups and the 13C NMR analysis showed that the sulfonyl groups were inserted mainly in C-4 of the b(1®6)-D-glucan... (Complete abstract click electronic access below) / Orientador: Roberto da Silva / Coorientador: Maria de Lourdes Corradi da Silva / Banca: Gabriela Alves Macêdo / Banca: Maria Inês Rezende / Banca: Jonas Contiero / Banca: Eleonora Cano Carmona / Doutor

Subsequent to the studies on precursor lead-acid systems by Daniel, Grove and Sindesten, practical lead-acid batteries began with the research and inventions of Raymond Gaston Planté in France as early as in 1859, and, even to-day, lead-acid battery remains the most successful battery system ever developed, and no other battery is yet able to compete with lead-acid batteries on cost grounds, albeit batteries based on other chemistries are rapidly catching up. In the past, although lead-acid battery designs have been optimized in several different directions, there are still certain new challenges facing the lead-acid battery designers as additional failure modes become evident in various use modes. There are three types of lead-acid batteries in common use: (a) batteries with flooded or excess electrolyte, (b) low-maintenance lead-acid batteries with a large excess of electrolyte, and (c) batteries with immobilized electrolyte and a pressure-sensitive valve usually referred to as absorptive glass-microfibre (AGM) valve-regulated lead-acid (VRLA) batteries. The flooded-electrolyte lead-acid battery requires checking of specific gravity of electrolyte, periodic addition of water to maintain electrolyte level above the plates and recharge soon after discharge to prevent hard sulfation that causes loss of capacity. The emission of acid fumes corrodes metallic parts in the vicinity of the battery, and the seepage of acid on the top cover of the batteries leads to leakage current resulting in increased self-discharge and ground-shunt hazards. To overcome these problems, AGMVRLA batteries based on oxygen-recombination cycle have emerged. These batteries offer the freedom of battery placement, cyclability without the addition of water or checking the specific gravity, increased safety, and superior performance in some instances. Both flooded-electrolyte and AGM-VRLA batteries can suffer from acid stratification. But, AGM-VRLA batteries are especially susceptible to failures owing to the heat generated by oxygen recombination within the cells as well as due to cell-to-cell variations in electrolyte volumes. Indeed, partial heating of AGM-VRLA batteries could cause dry-out with grid corrosion and even lead to thermal runaway. Consequently, mitigating temperature variations in AGM-VRLA batteries becomes seminal to their commercial success. A dissipation of local heat within the AGM-VRLA batteries can be achieved by adequately filling the void volume in the battery with a thermally conducting gel, such as a gel formed from colloidal silica and sulfuric-acid electrolyte. Although, conventional lead-acid batteries are considered rather a matured technology, significant research and development efforts are currently under way to enhance their performance. Indeed, many improvements have been made in the lead-acid battery since its invention, and although the essential electrochemistry remains unchanged, the modern lead-acid batteries have little semblance to those produced 50 years ago. Over the years, seminal advances have been made in the lead-alloys used, in the materials and design of separators, in battery packaging and in their construction methods, which have led to lead-acid batteries with improved performance, lighter weight and lower cost. This thesis is an attempt to develop lightweight hybrid-VRLA batteries.

No description available.

L'assemblage des nucléosomes est étroitement couplée à la synthèse des histones ainsi qu’à la réplication et la réparation de l’ADN durant la phase S. Ce processus implique un mécanisme de contrôle qui contribue soigneusement et de manière régulée à l’assemblage de l’ADN en chromatine. L'assemblage des nucléosomes durant la synthèse de l’ADN est crucial et contribue ainsi au maintien de la stabilité génomique. Cette thèse décrit la caractérisation par spectrométrie de masse(SM) des protéines jouant un rôle critique dans l’assemblage et le maintien de la structure chromatinienne. Plus précisément, la phosphorylation de deux facteurs d’assemblage des nucléosome, le facteur CAF-1, une chaperone d’histone qui participe à l'assemblage de la chromatine spécifiquement couplée à la réplication de l'ADN, ainsi que le complexe protéique Hir, jouant de plus un rôle important dans la régulation transcriptionelle des gènes d’histones lors de la progression normale du cycle cellulaire et en réponse aux dommages de l'ADN, a été examiné. La caractérisation des sites de phosphorylation par SM nécéssite la séparation des protéines par éléctrophorèse suivi d’une coloration a l’argent. Dans le chapitre 2, nous demontrons que la coloration à l’argent induit un artéfact de sulfatation. Plus précisément, cet artéfact est causé par un réactif spécifiquement utilisé lors de la coloration. La sulfatation présente de fortes similitudes avec la phosphorylation. Ainsi, l’incrément de masse observé sur les peptides sulfatés et phosphorylés (+80 Da) nécéssite des instruments offrant une haute résolution et haute précision de masse pour différencier ces deux modifications. Dans les chapitres 3 et 4, nous avons d’abord démontré par SM que Cac1, la plus grande sous-unité du facteur CAF-1, est cible de plusieurs sites de phosphorylation. Fait intéréssant, certains de ces sites contiennent des séquences consensus pour les kinases Cdc7-Dbf4 et CDKs. Ainsi, ces résultats fournissent les premières évidences que CAF-1 est potentiellement régulé par ces deux kinases in vivo. La fonction de tous les sites de phosphorylation identifiés a ensuite été évaluée. Nous avons démontré que la phosphorylation de la Ser-503, un site consensus de la DDK, est essentielle à la répréssion transcriptionelle des gènes au niveau des télomères. Cependant, cette phosphorylation ne semble pas être nécéssaire pour d’autres fonctions connues de CAF-1, indiquant que le blocage de la phsophorylation de Cac1 Ser-503 affecte spécifiquement la fonction de CAF-1 aux structures hétérochromatiques des télomères. Ensuite, nous avons identifiés une intéraction physique entre CAF-1 et Cdc7-Dbf4. Des études in vitro ont également demontré que cette kinase phosphoryle spécifiquement Cac1 Ser-503, suggérant un rôle potential pour la kinase Cdc7-Dbf4 dans l’assemblage et la stabilité de la structure hétérochromatique aux télomères. Finalement, les analyses par SM nous ont également permi de montrer que la sous-unité Hpc2 du complexe Hir est phosphorylée sur plusieurs sites consensus des CDKs et de Cdc7-Dbf4. De plus, la quantification par SM d’un site spécifique de phosphorylation de Hpc2, la Ser-330, s’est révélée être fortement induite suite à l’activation du point de contrôle de réplication (le “checkpoint”) suite au dommage a l’ADN. Nous montrons que la Ser-330 de Hpc2 est phopshorylée par les kinases de point de contrôle de manière Mec1/Tel1- et Rad53-dépendante. Nos données préliminaires suggèrent ainsi que la capacité du complex Hir de réguler la répréssion transcriptionelle des gènes d'histones lors de la progression du cycle cellulaire normal et en réponse au dommage de l'ADN est médiée par la phosphorylation de Hpc2 par ces deux kinases. Enfin, ces deux études mettent en évidence l'importance de la spectrométrie de masse dans la caractérisation des sites de phosphorylation des protéines, nous permettant ainsi de comprendre plus précisement les mécanismes de régulation de l'assemblage de la chromatine et de la synthèse des histones. / Nucleosome assembly entails a controlled mechanism that is tightly coupled to DNA and histone synthesis during DNA replication and repair in S-phase. Importantly, this contributes to the prompt and carefully orchestrated assembly of newly replicated DNA into chromatin, which is essential for the maintenance of genomic integrity. This thesis describes the mass spectrometric characterization of proteins critical in the regulation of nucleosome assembly behind the replication fork and chromatin structure. More specifically, the phosphorylation of Chromatin Assembly Factor 1 (CAF-1), a nucleosome assembly factor that uniquely functions during replication-coupled de novo nucleosome assembly in S-phase and the Hir protein complex, a second nucleosome assembly factor that also contributes to the transcriptional regulation of histone genes during normal cell cycle progression and in response to DNA damage, was examined. We first demonstrated that characterization of protein phosphorylation by mass spectrometry (MS), which often relies on the separation of proteins by gel electrophoresis followed by silver staining for visualization, should be given careful considerations. In chapter 2, we report a potential pitfall in the interpretation of phosphorylation modifications due to the artifactual sulfation of serine, threonine and tyrosine residues caused by a specific reagent used during silver staining. Sulfation and phosphorylation both impart an 80 Da addition of these residues making them distinguishable only with MS systems offering high resolution and high mass accuracy capabilities. Chapter 3 and 4 present the MS characterization of in vivo phosphorylation occurring on CAF-1 and Hir proteins, respectively. We first demonstrated that Cac1, the largest subunit of CAF-1, is phosphorylated on several novel residues containing the consensus sequences recognized by either Cdc7-Dbf4 (DDK) or cyclin-dependent kinases(CDKs). These results have provided the first evidence that CAF-1 is regulated by these two kinases in vivo. The function of all identified Cac1 phosphorylation sites was then assessed. In vivo phenotypic studies showed that the specific phosphorylation of Ser-503, a Cac1 DDK-like site identified in our study, is essential for heterochromatin-mediated telomeric silencing. Cac1-Ser-503 did not appear to be required for other known functions of CAF-1, including DNA damage resistance and mitotic chromosom segregation, indicating that blocking Cac1 phosphorylation on Ser-503 sepcifically cripples CAF-1 function at telomeres. Next, biochemical purifications identified a physical interaction between CAF-1 and Cdc7-Dbf4. Consistent with this physical interaction data, in vitro kinase assay studies showed that Cdc7-Dbf4 specifically phosphorylates Cac1 Ser-503 thereby uncovering a novel role for Cdc7-Dbf4 in heterochromatin assembly and/or stability that is potentially mediated through CAF-1. Finally, MS analysis also showed that the Hpc2 subunit of the Hir protein complex is phosphorylated on several CDK- and DDK-like consensus sites. Furthermore, MS quantification of a specific phosphorylation site,Hpc2 Ser-330, was shown to be highly induced following the activation of the DNA damage checkpoint in response to DNA damage. We show that Hpc2 Ser-330 is phopshorylated by checkpoint kinases in a Mec1/Tel1- and Rad53-dependent manner. Our preliminary data suggest that the ability of the Hir protein complex to regulate the transcriptional repression of histone genes during normal cell cycle progression and in response to DNA damage is mediated through the regulated phosphorylation of Hpc2 by these kinases. Finally, these two studies highlight the importance of mass spectrometry in characterizing protein phosphorylation events, which has yielded novel insights into the regulation of chromatin assembly by CAF-1 and histone synthesis mediated by Hir proteins.

L'assemblage des nucléosomes est étroitement couplée à la synthèse des histones ainsi qu’à la réplication et la réparation de l’ADN durant la phase S. Ce processus implique un mécanisme de contrôle qui contribue soigneusement et de manière régulée à l’assemblage de l’ADN en chromatine. L'assemblage des nucléosomes durant la synthèse de l’ADN est crucial et contribue ainsi au maintien de la stabilité génomique. Cette thèse décrit la caractérisation par spectrométrie de masse(SM) des protéines jouant un rôle critique dans l’assemblage et le maintien de la structure chromatinienne. Plus précisément, la phosphorylation de deux facteurs d’assemblage des nucléosome, le facteur CAF-1, une chaperone d’histone qui participe à l'assemblage de la chromatine spécifiquement couplée à la réplication de l'ADN, ainsi que le complexe protéique Hir, jouant de plus un rôle important dans la régulation transcriptionelle des gènes d’histones lors de la progression normale du cycle cellulaire et en réponse aux dommages de l'ADN, a été examiné. La caractérisation des sites de phosphorylation par SM nécéssite la séparation des protéines par éléctrophorèse suivi d’une coloration a l’argent. Dans le chapitre 2, nous demontrons que la coloration à l’argent induit un artéfact de sulfatation. Plus précisément, cet artéfact est causé par un réactif spécifiquement utilisé lors de la coloration. La sulfatation présente de fortes similitudes avec la phosphorylation. Ainsi, l’incrément de masse observé sur les peptides sulfatés et phosphorylés (+80 Da) nécéssite des instruments offrant une haute résolution et haute précision de masse pour différencier ces deux modifications. Dans les chapitres 3 et 4, nous avons d’abord démontré par SM que Cac1, la plus grande sous-unité du facteur CAF-1, est cible de plusieurs sites de phosphorylation. Fait intéréssant, certains de ces sites contiennent des séquences consensus pour les kinases Cdc7-Dbf4 et CDKs. Ainsi, ces résultats fournissent les premières évidences que CAF-1 est potentiellement régulé par ces deux kinases in vivo. La fonction de tous les sites de phosphorylation identifiés a ensuite été évaluée. Nous avons démontré que la phosphorylation de la Ser-503, un site consensus de la DDK, est essentielle à la répréssion transcriptionelle des gènes au niveau des télomères. Cependant, cette phosphorylation ne semble pas être nécéssaire pour d’autres fonctions connues de CAF-1, indiquant que le blocage de la phsophorylation de Cac1 Ser-503 affecte spécifiquement la fonction de CAF-1 aux structures hétérochromatiques des télomères. Ensuite, nous avons identifiés une intéraction physique entre CAF-1 et Cdc7-Dbf4. Des études in vitro ont également demontré que cette kinase phosphoryle spécifiquement Cac1 Ser-503, suggérant un rôle potential pour la kinase Cdc7-Dbf4 dans l’assemblage et la stabilité de la structure hétérochromatique aux télomères. Finalement, les analyses par SM nous ont également permi de montrer que la sous-unité Hpc2 du complexe Hir est phosphorylée sur plusieurs sites consensus des CDKs et de Cdc7-Dbf4. De plus, la quantification par SM d’un site spécifique de phosphorylation de Hpc2, la Ser-330, s’est révélée être fortement induite suite à l’activation du point de contrôle de réplication (le “checkpoint”) suite au dommage a l’ADN. Nous montrons que la Ser-330 de Hpc2 est phopshorylée par les kinases de point de contrôle de manière Mec1/Tel1- et Rad53-dépendante. Nos données préliminaires suggèrent ainsi que la capacité du complex Hir de réguler la répréssion transcriptionelle des gènes d'histones lors de la progression du cycle cellulaire normal et en réponse au dommage de l'ADN est médiée par la phosphorylation de Hpc2 par ces deux kinases. Enfin, ces deux études mettent en évidence l'importance de la spectrométrie de masse dans la caractérisation des sites de phosphorylation des protéines, nous permettant ainsi de comprendre plus précisement les mécanismes de régulation de l'assemblage de la chromatine et de la synthèse des histones. / Nucleosome assembly entails a controlled mechanism that is tightly coupled to DNA and histone synthesis during DNA replication and repair in S-phase. Importantly, this contributes to the prompt and carefully orchestrated assembly of newly replicated DNA into chromatin, which is essential for the maintenance of genomic integrity. This thesis describes the mass spectrometric characterization of proteins critical in the regulation of nucleosome assembly behind the replication fork and chromatin structure. More specifically, the phosphorylation of Chromatin Assembly Factor 1 (CAF-1), a nucleosome assembly factor that uniquely functions during replication-coupled de novo nucleosome assembly in S-phase and the Hir protein complex, a second nucleosome assembly factor that also contributes to the transcriptional regulation of histone genes during normal cell cycle progression and in response to DNA damage, was examined. We first demonstrated that characterization of protein phosphorylation by mass spectrometry (MS), which often relies on the separation of proteins by gel electrophoresis followed by silver staining for visualization, should be given careful considerations. In chapter 2, we report a potential pitfall in the interpretation of phosphorylation modifications due to the artifactual sulfation of serine, threonine and tyrosine residues caused by a specific reagent used during silver staining. Sulfation and phosphorylation both impart an 80 Da addition of these residues making them distinguishable only with MS systems offering high resolution and high mass accuracy capabilities. Chapter 3 and 4 present the MS characterization of in vivo phosphorylation occurring on CAF-1 and Hir proteins, respectively. We first demonstrated that Cac1, the largest subunit of CAF-1, is phosphorylated on several novel residues containing the consensus sequences recognized by either Cdc7-Dbf4 (DDK) or cyclin-dependent kinases(CDKs). These results have provided the first evidence that CAF-1 is regulated by these two kinases in vivo. The function of all identified Cac1 phosphorylation sites was then assessed. In vivo phenotypic studies showed that the specific phosphorylation of Ser-503, a Cac1 DDK-like site identified in our study, is essential for heterochromatin-mediated telomeric silencing. Cac1-Ser-503 did not appear to be required for other known functions of CAF-1, including DNA damage resistance and mitotic chromosom segregation, indicating that blocking Cac1 phosphorylation on Ser-503 sepcifically cripples CAF-1 function at telomeres. Next, biochemical purifications identified a physical interaction between CAF-1 and Cdc7-Dbf4. Consistent with this physical interaction data, in vitro kinase assay studies showed that Cdc7-Dbf4 specifically phosphorylates Cac1 Ser-503 thereby uncovering a novel role for Cdc7-Dbf4 in heterochromatin assembly and/or stability that is potentially mediated through CAF-1. Finally, MS analysis also showed that the Hpc2 subunit of the Hir protein complex is phosphorylated on several CDK- and DDK-like consensus sites. Furthermore, MS quantification of a specific phosphorylation site,Hpc2 Ser-330, was shown to be highly induced following the activation of the DNA damage checkpoint in response to DNA damage. We show that Hpc2 Ser-330 is phopshorylated by checkpoint kinases in a Mec1/Tel1- and Rad53-dependent manner. Our preliminary data suggest that the ability of the Hir protein complex to regulate the transcriptional repression of histone genes during normal cell cycle progression and in response to DNA damage is mediated through the regulated phosphorylation of Hpc2 by these kinases. Finally, these two studies highlight the importance of mass spectrometry in characterizing protein phosphorylation events, which has yielded novel insights into the regulation of chromatin assembly by CAF-1 and histone synthesis mediated by Hir proteins.

Made available in DSpace on 2014-06-11T19:32:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-02-06Bitstream added on 2014-06-13T21:05:14Z : No. of bitstreams: 1 vasconcelos_afd_dr_rcla.pdf: 873436 bytes, checksum: e2a838b6410dbd9cdc2bc380f1261e4e (MD5) / Exopolissacarídeos do tipo β-glucanas são polímeros produzidos por uma grande variedade de microrganismos e podem possuir diferentes propriedades físicas, químicas e aspectos estruturais. Esses biopolímeros apresentam atividades biológicas interessantes (antitumor, antiviral, anticoagulante) e aplicações comerciais como produtos em alimentos, cosméticos e farmacêuticos. Entretanto, para a aplicação dessas moléculas, é necessário primeiramente o conhecimento de suas estruturas químicas. Assim, o objetivo deste trabalho foi a produção, caracterização química de quatro exopolissacarideos (EPSGRAVIOLA, EPSMANGA, EPSPINHA e EPSLARANJA) de isolados de Botryosphaeria obtidos de frutas tropicais em decomposição e crescidos em sacarose como única fonte de carbono, determinando o melhor EPS para realizar testes de atividade anticoagulante. A homogeneidade de cada EPS foi determinada por cromatografia de filtração em gel, os quais eluíram como um único pico. Hidrólise ácida total e análise por HPAEC/PAD mostrou glucose como constituinte básico. Dados de metilação e RMN de 13C indicaram que os EPSMANGA, EPSPINHA e EPSLARANJA são glucanas lineares unidas por ligações do tipo β(1®6) e o EPSGRAVIOLA é uma glucana com ligações β(1®3) e com ramificações em C-6 de resíduos glucopiranosídicos. O espectro de FT-IR mostrou uma banda em 891 cm-1, e a espectroscopia de 13C NMR mostrou que todas as ligações eram do tipo β. Estudos realizados com o corante Vermelho Congo indicaram que os EPS possuem conformação em tripla hélice. O EPSLARANJA, uma b- D-(1®6)-glucana, foi submetido a sulfatação visando induzir a atividade anticoagulante e melhorar a solubilidade da molécula em solução, importante para a atividade biológica. Espectros de FT-IR mostraram bandas em 808 and 1252 cm-1, indicando a entrada dos grupos sulfato e as análises de RMN de 13C mostraram... / Exopolysaccharides (EPS) as β-glucans are polymers produced by a great variety of microorganisms and can possess different physical and chemical properties, and structural features. These biopolymers having interesting biological activities (antitumor, anti-viral, anticoagulant), and commercial applications in foods, cosmetics and pharmaceutical products. However, for the applications of these macromolecules, it is first necessary to understand their chemical structures. Therefore the goal of that study was the production, chemical characterization and biological activity of four exopolysaccharides (EPSGRAVIOLA, EPSMANGO, EPSPINHA and EPSORANGE) obtained from Botryosphaeria strains isolated from rotting tropical fruit grown on sucrose as carbon and the best EPS was used for the anticoagulant activity The homogeneity of each EPS was determined by gel filtration chromatography, which was eluted as a single peak. Total acid hydrolysis and HPAEC/PAD analysis of each EPS yielded only glucose. Data from methylation analysis and 13C NMR spectroscopy indicated that the EPSMANGO, EPSPINHA and EPSORANGE consisted of a linear chain of (1-6)- linked glucopyranosyl residues and EPSGRAVIOLA consisted of a main chain of glucopyranosyl (1-3) linkages substituted at O-6. FTIR spectra showed one band at 891 cm-1, and 13C NMR spectroscopy showed that all glucosidic linkages were of the β-configuration. Dye-inclusion studies with Congo Red indicated that each EPS existed in a triple-helix conformational state. The EPSORANGE, a β-(1®6)- D-glucan was submitted to a sulfation to induce anticoagulant activity and also to make this EPS more soluble, which is in favor to its biological action. The FT-IR spectrum showed bands at 808 and 1252 cm-1 indicating insertion of sulfonyl groups and the 13C NMR analysis showed that the sulfonyl groups were inserted mainly in C-4 of the b(1®6)-D-glucan... (Complete abstract click electronic access below)

This dissertation deals with the study of durability and degradation repair mortars for reinforced concrete structures. In its theoretical part, there are the research findings on the behavior of repair mortars exposed to corrosive environments with different exposure time and selected high temperatures. Processes occurring in repair mortars during their loading at high temperatures or when exposed to chemically aggressive environments are described, We can find recipes designed for cementitious binder based with a specific replacement using slag or fly ash in its practical part. The object of the research was to determine the durability of the proposed repair mortars, and determine their suitability for use on concrete structures, which may be exposed to a synergistic effect of chemically aggressive environments with high temperatures simulating fire.

The direct variable costs for heat and electricity production based on solid biomass fuel combustion is approximately 3-5 times lower than the costs in a fossil fuel-oil based boiler in Sweden. In addition waste derived biomass fuels are typically much cheaper than biomass not classified as waste. The introduction of the waste derived fuels; wastewater treatment sludge, demolition wood, and animal waste in a 50MWth circulating fluidized bed (CFB) biomass boiler located in Perstorp, Sweden, led to rapid deposit buildup in superheaters, heavy ash accumulation in economizers and failing boiler tubes and vortex finders that forced frequent boiler shutdowns. This in turn increased the use of expensive oil (fossil fuel) in backup boilers and the CO2 footprint of the on-site energy conversion system. This work aims to increase the general mechanistic understanding of combustion systems using complex fuels, and includes: A mapping of the boiler failure and preventive maintenance statistics; elemental composition analysis of ash, deposits and fuel fractions; flue-gas composition measurements; chemical speciation analysis; an attempt to describe the overall ash transformation reactions and mass balance throughout the combustion process. Scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) was used to analyze the elemental composition of ash and deposits. The SEM-EDS results were used together with data from X-ray powder diffraction (XRD) analysis, thermodynamic phase data, and equilibrium calculations in an attempt to quantify the crystalline phases and the overall ash transformation of the process. Based on the findings concerning ash transformation and the failure statistics, it has been possible to identify generic key parameters regarding boiler design and process parameters, enabling major improvements of the CFB boiler availability, a lower overall energy conversion cost and a reduced CO2 footprint. / Den direkta rörliga kostnaden för värme-och elproduktion baserad på fast biobränsle är ungefär 3-5 gånger lägre än kostnaden för fossiloljebaserad produktion. Avfallsklassade fasta biobränslen är vidare oftast betydligt billigare än fasta biobränslen som inte är klassade som avfall. Införandet av de avfallsklassade bränslena; reningsslam, rivningsvirke, och animaliskt avfall i en 50MWth cirkulerande fluidiserad bädd (CFB) -panna, ledde till kraftig beläggningstillväxt i överhettare och ackumulering av aska i ekonomisers, samt haveri av panntuber och centrumrör i cyklonerna, som tvingade fram frekventa pannstopp. Detta ökade i sin tur användningen aveldningsolja (fossilt bränsle) i reservkrafts-pannor vilket resulterade i ett större CO2 utsläpp och en högre kostnad för energiomvandlingen på siten. Detta arbete syftar till att öka den allmänna mekanistiska förståelsen av förbränningssystem som använder komplexa bränslen, och omfattar; haveri- och underhållsstatistik, elementarsammansättningsanalys av aska, beläggningar och bränslefraktioner, rökgasens sammansättning, kemisk specificering av askor och beläggningar, ett försök att beskriva de övergripande askomvandlingsreaktionerna, samt en massbalans för förbränningsprocessen. Svepelektronmikroskop (SEM) utrustat med energidispersiv röntgenspektroskopi (EDS) användes för att analysera den elementära sammansättningen av aska och beläggningar. SEM-EDS-resultaten användes tillsammans med pulverröntgendiffraktionsanalys (XRD), termodynamiska fasdata, och jämviktsberäkningar i ett försök att kvantifiera de kristallina faserna och de övergripande askomvandlingsreaktionerna i processen. Baserat på resultaten rörande askomvandling och haveristatistik, har det varit möjligt att identifiera generiska nyckelparametrar gällande panndesign och processparametrar, som möjliggjort stora förbättringar av CFB pannans tillgänglighet, en lägre totalkostnad för energiomvandlingen på siten samt ett minskat CO2-utsläpp.

Ce travail traite d’un problème de pollution liée à la présence de métaux de base dans des passifs environnementaux issus d’un traitement métallurgique des minerais sulfureux cuivre – zinc provenant de la mine de Kipushi en République Démocratique du Congo. L’objectif principal de ce travail a été d’arriver à proposer des scénarios de gestion durable au passif environnemental de la filière présentant les risques environnementaux les plus élevés. Pour cela, on a d’abord procédé à une identification des différents problèmes environnementaux tout au long de la filière de traitement sur les quatre sites d’exploitation. Ensuite on a prélevé des échantillons puis procéder par des tests de disponibilité à la lixiviation à l’eau déminéralisée pour évaluer les fractions solubles des métaux de base présents et aussi par des tests de conformité de mise en décharge afin de classer ces rejets conformément à la directive européenne 2003-33-CE. Ainsi, les rejets Ex – UZK ont été identifiés comme les plus dangereux de la filière au regard de cette directive, car les quantités lixiviées de cuivre et de zinc dans ces rejets ont dépassé largement les limites fournies par la directive, et donc ils ne peuvent même pas être mis en décharge de classe I sans traitement métallurgique préalable pouvant permettre leur dépollution. <p>Par contre, les autres rejets de la filière, en l’occurrence les rejets de flottation de Kipushi et les scories de fusion pour matte de cuivre, peuvent eux être acceptés en décharge de classe I, sans traitement préalable au regard des limites fournies par la même directive. Les procédés de lixiviation acide chaude et de digestion ont été proposés et retenus comme scénarios de gestion durable à appliquer à ces rejets Ex – UZK, car ils se réalisent tous deux en milieu acide sulfurique d’une part et d’autre part leur application et surtout leur faisabilité en République Démocratique du Congo reste possible ;en outre ils aboutissent à des nouveaux rejets contenant le fer sous forme d’hématite, pouvant être stocké aisément et durablement dans la nature, ce qui est conforme au principe du développement durable. Nous avons tenté de modéliser ces deux scénarios en discutant et comparant la circulation des flux de matière dans les deux procédés, d’abord autour de chaque opération métallurgique unitaire, et ensuite sur l’ensemble du procédé. Ainsi nous avons pu chiffrer tous les flux entrant et sortant dans le système étudié, en considérant 1000 kg de rejets Ex –UZK alimentés. Cette quantification nous a permis de comparer les coûts opératoires de ces deux procédés. Les résultats obtenus dans la présente étude sont encourageants et nous ont permis de formuler des recommandations pour les études ultérieures éventuelles dont les résultats pourront l’enrichir davantage, notamment sur les aspects technologiques, économiques et environnementaux, de manière à faciliter les applications sur terrain.<p><p>This work deals with environmental liabilities consisting of base metals pollution due to metallurgical processing of copper – zinc sulphide ores in Kipushi mine in Democratic Republic of Congo. The main objective of this work was to propose sustainable management scenarios for the most important environmental liabilities from metallurgical sector. For this purpose, liabilities were first identified on four metallurgical plants. Then, leaching tests with deionized water were carried out to assess the soluble fractions of base metals. These effluents were also classified according to the test described in european decision 2003-33-EC, which determines the conformity of waste to landfill. Ex – UZK effluents are the most dangerous from this sector, according to this directive, since the quantities of leached copper and zinc were far beyond the limits :they cannot be sent to class I landfill without prior metallurgical processing. However, other effluents like flotation wast and Lubumbashi slag originating from melting for copper matte, are acceptable without prior treatment. Hot acid leaching and digestion were proposed as sustainable management scenarios for to these Ex – UZK waste because :both can be performed in sulfuric acid and they are feasible in Democratic Republic of Congo. They also lead to an iron – rich waste consisting of hematite that can be stored easily and sustainably in nature, which is consistent with the principle of sustainable development. We have modeled these two scenarios by discussing and comparing the flows in both processes, first for each individual metallurgical unit process, and then for the whole chain of value. So we could assess all the inputs and outputs of the studied system, expressed per ton of Ex – UZK waste. The operating costs of both processes were calculated and compared. The results are encouraging. Recommendations were proposed for further studies, in order to investigate more deeply the technological, economical and environmental aspects, to facilitate the final application. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished