Dissertations / Theses on the topic 'Lewis structure'

La difficulté pour interpréter les résultats issus de la mécanique quantique est toujours un souci pour les chimistes. Plusieurs méthodes ont été proposées pour extraire, à partir de fonctions d'onde, des images permettant au chimiste de mieux comprendre la structure électronique et les propriétés des molécules et des cristaux. C'est dans cette famille des méthodes interprétatives que rentre la méthode MPD développée au cours de cette thèse, qui consiste à chercher des domaines de l'espace pour lesquels la probabilité de trouver un nombre donné d'électrons est maximale. Cette recherche est un problème d'optimisation, qui exige le développement d'algorithmes d'optimisations adaptés. Dans un premiers temps un algorithme simple d'optimisation discrète a été utilisé. Cet algorithme ne s'est pas avéré suffisamment efficace. Un nouvel algorithme, basé sur la définition d'une direction de montée, a alors été implémenté, se montrant beaucoup plus efficace et précis. Le programme écrit a permis d'explorer les potentialités interprétatives de la méthode MPD dans un certain nombre de systèmes modèles, pour des fonctions de type Hartree-Fock. La méthode MPD a fourni des résultats satisfaisants dans la recherche de domaines associés à des liaisons covalentes et aux paires libres des atomes, et a permis de trancher entre les deux principales images proposées pour la liaison à trois électrons. Quelques limites de la méthode et des questions ouvertes ont été mises en évidence lors des applications, et discutées, notamment les questions de multiplicité de solutions et de la répartition de l'espace entre ces solutions.

Le stockage et le relargage contrôlé du dihydrogène est devenu un domaine important de recherche visant à répondre à une demande énergétique grandissante. Bien que le borazane (NH3-BH3) ait été identifié comme un candidat de choix dû à sa grande capacité de stockage (16.9 wt.% H2), les chercheurs ont mis en évidence certaines limitations telles que des difficultés de mise en forme et des difficultés de régénération du matériau.Nous avons tenté de répondre à ces problématiques en concevant de nouveaux polymères contenant des fonctions de type amine-borane dans leur chaîne principale (polyboramines) et sur les chaînes latérales, afin d’étudier l’influence du squelette polymère sur les propriétés du matériau et sa réactivité associée. Nos objectifs ont visé une facilité de synthèse et de mise en forme mais aussi l'éventualité d'une régénération simple et directe du réservoir après relargage du dihydrogène. Nous avons synthétisé ces polymères en une étape quantitativement et sélectivement à partir de fragments commerciaux ou facilement accessibles. Nous avons observé une influence conséquente de la matrice polymère sur les paramètres cinétiques et thermodynamiques de la déshydrogénation, à la suite de quoi nous avons étudié les paramètres structuraux influençant la réactivité. De plus les polymères obtenus après déshydrogénation ont montré d’intéressantes propriétés mécaniques et chimiques. Ces résultats nous ont encouragés à nous pencher vers le recyclage de ces réservoirs à hydrogène
Dihydrogen storage and controlled release has become an essential area of research aspiring to answer the ever-growing energetic demand. If ammonia-borane (NH3-BH3) was early on identified as a premium candidate to constitute a H2 reservoir, due to its maximum storage capacity (16.9 wt.% H2), researchers have then identified its shortcomings such as poor processability and troublesome material recycling.We have proposed to address these issues through the synthesis of new polymers containing the amine-borane motif in the main-chain (polyboramine) or as pendant moieties, harnessing improvements brought by the polymer backbone on the reactivity and material properties. We aimed at an ease of preparation, an enhanced processability but also an access to recyclable materials via simple re-hydrogenation techniques. We have synthesized these polymers from available organic building blocks by simple treatment of diammonium and bisboronic acids with LiAlH4. We showed that the polymer matrix has a drastic effect on kinetic and thermodynamic parameters of the dehydrogenation process. We investigated the role of structural parameters on the reactivity. Moreover, polymers obtained after dehydrogenation (H2 release) still feature interesting mechanical and chemical properties. These results give us hope regarding the recycling of these hydrogen reservoirs

Cette thèse traite de l'utilisation de molécules dîtes ambiphiles, comportant à la fois un site donneur et accepteur d'électrons, en chimie organométallique, en tant que ligand. Dans le premier chapitre, une étude bibliographique décrit l'utilisation des acides de Lewis du groupe 13 en tant que co-catalyseur en chimie organométallique, afin de mieux comprendre quel rôle pourrait jouer celui-ci au sein d'un ligand ambiphile coordiné sur un métal de transition. Les différents modes de coordination de ces ligands sont examinés. Les rares contributions traitant de la réactivité de ce type de complexes sont également décrites. Le second chapitre décrit la synthèse par couplage bore-carbone d'une nouvelle famille de ligands ambiphiles, 2-picolylboranes. En fonction des substituants du bore, ces composés sont obtenus sous forme dimère ou monomère fermé par interactions datives donneur-accepteur, inter ou intramoléculaires. Le comportement en solution du 2-picolylBCy2 a été examiné attentivement. Un équilibre entre la forme dimère et monomère est mis en évidence. Des calculs théoriques valident nos conclusions. La coordination de ce ligand sur plusieurs précurseurs métalliques est étudiée. Un exemple rare de coordination pontante donneur->Ru-Cl->accepteur a été caractérisé dans le complexe [(p-cym)RuCl2(2-picolylBCy2)]. Dans le troisième chapitre, la synthèse par hydroboration d'une famille de ligands ambiphiles, 1,2-phosphinoethylborane, est décrite. Deux complexes de ruthénium neutres contenant ces ligands, ainsi que leur dérivés cationiques sont caractérisés. Des tests catalytiques préliminaires d'hydrosilylation du benzaldéhyde avec l'un des complexes cationiques ont montré la dégradation rapide du pré-catalyseur en un complexe ruthénacycle original. Sa réactivité avec un chloroborane et un chloroalane est étudiée
The present contribution deals with the use of ambiphilic molecules featuring both a Lewis base and a Lewis acid site, as ligands in organometallic chemistry. In the first chapter, a bibliographic study describes the behaviour of Lewis acids of group 13 in organometallic chemistry. Their role as co-catalysts is examined in order to better understand how the Lewis acid could behave in a complex featuring an ambiphilic ligand. The different coordination modes of those ligands are reviewed. The rare contributions dealing with the reactivity of those complexes are also examined. The second chapter describes the synthesis by carbon-boron coupling of a new family of ambiphilic ligands, namely 2-picolylboranes. Depending on the borane substituents, they are obtained as dimer or closed monomer via inter or intramolecular donor-acceptor dative interaction. The behaviour of 2-picolylBCy2 in solution is examined in details by NMR. An equilibrium between a dimer and a closed monomer form is evidenced. Theoretical calculations ascertain our conclusions. Coordination of this ligand to several transition metal precursors is studied. .

Il s'agissait dans ce travail de préparer des composés fluorés de structure de type HTB ou hollandite au sein desquels la présence d'autres anions tels que OH- ou encore O2- viennent se substituer au fluor. Nous avons voulu dans ce travail mieux comprendre par une approche " chimie du solide " les propriétés de morphologie, de stabilité thermique et d'acidité des ces composés. Des études par diffraction neutronique couplées à une analyse par FTIR nous ont permis de mieux appréhender leurs propriété physico-chimiques. Nos résultats ont mis en avant les rôles joués par les cations, les anions et la structure sur les différentes propriétés et notamment l'importance d'un nouveau paramètre, [khi]/r, qui permet d'expliquer à la fois la force des sites acides et la stabilité thermique de ces composés. L'eau de constitution, le taux et la nature des groupements OH' sont des paramètres clefs qui conditionnent la stabilité thermique et les propriétés acido-basiques de ces composés à anions mixtes.

Cette thèse traite de l'utilisation de molécules dîtes ambiphiles, comportant à la fois un site donneur et accepteur d'électrons, en chimie organométallique, en tant que ligand.

Dans le premier chapitre, une étude bibliographique décrit l'utilisation des acides de Lewis du groupe 13 en tant que co-catalyseur en chimie organométallique, afin de mieux comprendre quel rôle pourrait jouer celui-ci au sein d'un ligand ambiphile coordiné sur un métal de transition. Les différents modes de coordination de ces ligands sont examinés. Les rares contributions traitant de la réactivité de ce type de complexes sont également décrites.

Le second chapitre décrit la synthèse par couplage bore-carbone d'une nouvelle famille de ligands ambiphiles, 2-picolylboranes. En fonction des substituants du bore, ces composés sont obtenus sous forme dimère ou monomère fermé par interactions datives donneur-accepteur, inter ou intramoléculaires. Le comportement en solution du 2-picolylBCy2 a été examiné attentivement. Un équilibre entre la forme dimère et monomère est mis en évidence. Des calculs théoriques valident nos conclusions. La coordination de ce ligand sur plusieurs précurseurs métalliques est étudiée. Un exemple rare de coordination pontante donneur→Ru-Cl→accepteur a été caractérisé dans le complexe [(p-cym)RuCl2(2-picolylBCy2)].

Dans le troisième chapitre, la synthèse par hydroboration d'une famille de ligands ambiphiles, 1,2-phosphinoethylborane, est décrite. Deux complexes de ruthénium neutres contenant ces ligands, ainsi que leur dérivés cationiques sont caractérisés. Des tests catalytiques préliminaires d'hydrosilylation du benzaldéhyde avec l'un des complexes cationiques ont montré la dégradation rapide du pré-catalyseur en un complexe ruthénacycle original. Sa réactivité avec un chloroborane et un chloroalane est étudiée.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemical Engineering, 2015.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 111-122).
Catalysis provides a technology-based method to efficiently convert raw materials to useful products. Zeolite catalysis enables high product selectivity and is widely used due to the high activity, thermal stability, and well-defined crystalline pore structure of zeolites. Moreover, incorporation of metals into the framework of hydrophobic zeolites results in water-tolerant Lewis acids. This thesis discusses the synthesis, characterization, and structure-activity relations of metal-substituted Beta zeolites in the conversion of oxygenates. Chapter 2 discusses the application of dynamic nuclear polarization (DNP) NMR to characterize natural-abundance Sn-Beta. An indirect use of proton spin diffusion resulted in a 50-fold signal increase and the ability to observe natural-abundance ¹¹⁹Sn-Beta in <24 h. Since DNP NMR only enables efficient detection of spin-1/2 nuclei, a secondary method of adsorbing pyridine on framework metal sites in zeolites permits further characterization of quadrupolar nuclei. Chapter 3 examines how pyridine chemical shift can resolve framework and extraframework metal sites as well as provide a measure of Lewis acidity. Additionally, solid-state NMR offers the ability to quantify the concentrations of these sites. Promoter addition to the active sites of zeolites can further provide cooperative catalysis and tuning of product distribution. Chapter 4 describes the borate-promoted Sn- Beta zeolite-catalyzed conversion of aldoses via an unusual 1,2 carbon shift mechanism. The addition of a borate promoter to Sn-Beta resulted in a complete shift towards near-equilibrium epimerization product distribution. Chapter 5 further examines the catalytic consequences of varying key reaction parameters such as the borate to sugar ratio, pH, and reaction time. This full factorial experimental design showed that epimerization dominates under neutral conditions and is still active at substoichiometric borate to sugar ratio. This observation suggests that borate is acting pseudo-catalytically potentially through interaction with the Sn site. These findings motivated a detailed mechanistic study, as discussed in Chapter 6. Solid-state NMR proximity measurements in conjunction with directed removal of substrate functionality led to a proposed Bilik-type reaction mechanism involving borate. This body of work contributes to a molecular-level understanding of Lewis acid sites in hydrophobic zeolites. Furthermore, the ability to tailor Lewis acid sites through promoter incorporation can enable novel catalytic reactions.
by William Robert Gunther.
Ph. D.

Ce travail a essentiellement porté sur la description et la rationalisation de certaines propriétés des complexes du Zinc contenant des ligands de base de Schiff par le biais d’approches mixtes théorique et expérimentale. La première partie de ce travail concerne la synthèse et la caractérisation d’un nouveau complexe dinucléaire de Zn(II) à ligand base de Schiff tétra-azoté N4. Ce complexe s’auto-assemble en hélice à double brin avec un environnement tétraédrique rarement observé pour l’ion Zn2+ avec ce type de ligand. Ce complexe s’est avéré être thermodynamiquement instable en présence de traces d’eau, subissant ainsi une démétallation rapide. De ce fait, sa réactivité vis-à-vis de l’eau a été étudiée par des mesures spectroscopiques et des calculs DFT. Puis, le mécanisme réactionnel de démétallation a été élucidé pour la première fois et pourrait facilement être généralisé à l’hydrolyse des complexes Zn-sal(ph)en apparentés. Dans la seconde partie, le caractère acide de Lewis, principal facteur de la réactivité/coordination des complexes Zn-sal(ph)en a été étudié au moyen des descripteurs de la DFT-conceptuelle. Une analyse préliminaire a été réalisée sur un prototype modèle à savoir [ZnCl4]2-, et les résultats ont été généralisés aux complexes de Zn-sal(ph)en comportant différents types d’espaceurs diamine (flexible, semi-rigide, et rigide) afin de rationaliser l’acidité de Lewis de ces complexes avec la nature du pont diamine. L’inclusion des densités des états excités par le biais du descripteur dual dit « state specific dual descriptor» a permis de décrire avec succès la réactivité appropriée du complexe choisi. Enfin, la troisième partie de ce travail, est consacré à l’effet dit de « self-interaction » survenue dans la modélisation de la réaction de cyclo-addition du CO2 sur les époxydes catalysée par un complexe Zn-N4 base de Schiff en présence de NBu4X (X=I). Cette erreur menant à des profils énergétiques irréalistes au niveau DFT, a été identifiée et une nouvelle approche théorique a été proposée et développée afin de contourner cette erreur
In this work, we focus our interest on the description and rationalization of some properties of Zinc complexes of Schiff bases schemes through theoretical and experimental approaches. The first study deals with the syntheses and characterization of a novel Zn-N4-Schiff base L= ((±) -trans-N, N’-Bis(2-aminobenzylidene)-1,2-diaminocyclohexane) showing an unexpected self-assembled double-stranded helicate structure , in which zinc atoms are in distorted tetrahedral environments, revealing an M- (R, R) left-handed helicity in its asymmetric unit. This dimer is thermodynamically unstable in presence of water traces and undergoes a rapid demetallation process that is studied by both experimental and theoretical approaches. The reaction is monitored through DOSY NMR analysis, and the theoretical mechanism of the demetallation process is elucidated for the first time using DFT method and which should be easily generalized to the demetallation of N2O2 sal(ph)en Zn complexes. In the second part of this study, the Lewis acidic behavior, the main factor of the reactivity/coordination of Zn-sal(ph)en complexes, is studied using conceptual density functional theory descriptors. This Lewis acidic character is addressed in a first stage to a prototype complex, namely [ZnCl4]2- and the results have been generalized to Zn-sal(ph)en complexes with different diamine bridges through flexible to semi-rigid then to rigid ranges, in order to characterize and rationalize this Lewis acid effect in relation with the nature of the diamine bridge. The inclusion of the electronic excited state densities by the so-called state specific dual descriptor allows us to recover successfully the appropriate reactivity of these chosen complexes. Finally, in the third part, we consider the effect of the « self-interaction » occurring when modeling the cycloaddition of CO2 to epoxide reactions catalyzed via the binary system Zn-N4 Schiff base /NBu4X (X=I). This error leading to unrealistic energy profiles at the DFT level has been identified and a new theoretical approach is proposed and developed to correct this error

Metal organic frameworks have gained much attention due to their tunable pore sizes and very high surface areas. With the discovery many of these type materials the need has raised to look into new applications of theses porous frameworks. This thesis focuses on the synthesis of a new perovskite-type metal organic framework and measurement of its thermal conductivity in search of its applicability as a thermoelectric material. The second part of this work focuses on the synthesis of a metal organic framework incorporated with a Lewis pair for the first time. The optimum loading amount of the Lewis pair into the framework was also investigated.

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This research aims at identifying the learning problems in newly undergraduate students at university, interpreting the nature and causes of these problems, offering subsidies to overcome these difficulties and enabling a meaningful learning through which students give meaning to their learning. As an object for this work was chosen the theme Chemical Bonds - where were studied the forces between atoms to form molecules, compound ions and ionic crystalline structures - and is characterized as one of the most important subjects of Chemistry. In research, it was used a questionnaire with five open questions, answered by 147 students from the early periods of degrees in Chemistry at Universidade Federal do f Rio Grande do Norte. The answers revealed uncertainty on the part of students, both conceptual and representation, with superficial justifications, always using the octet rule to describe models of chemical bonds. Results suggest that these students had inadequate training in high school and that the examinations for entrance into the ranks were made according to flexible criteria less demanding in terms of knowledge. These observations have led to the conclusion that for future changes, it is necessary for high schools and in the early periods in universities favoring the adoption of pedagogical approaches in context and applying strategies to overcome the teaching of superficial memorization on Chemical Bonds, which probably have applied to the teaching of other subjects of chemistry
Este trabalho teve o objetivo de identificar problemas de aprendizagem em alunos de gradua??o rec?m ingressante na universidade, interpretar a natureza e as causas desses problemas, oferecendo subs?dios para supera??o de tais dificuldades e possibilitando uma aprendizagem significava atrav?s da qual o aluno atribua sentido em seu aprendizado. Para o desenvolvimento desse trabalho foi escolhido o tema Liga??es Qu?micas - onde se estudam as for?as que agem entre os ?tomos para formar mol?culas, ?ons compostos ou estruturas cristalinas i?nicas -, que se caracteriza como um dos mais importantes assuntos da Qu?mica. Para isso, utilizou-se um question?rio com cinco perguntas abertas, respondidas por 147 estudantes dos per?odos iniciais das gradua??es em Qu?mica da Universidade Federal do Rio Grande do Norte. As respostas obtidas revelaram inseguran?a dos estudantes, tanto em termos conceituais quanto de representa??o, com justificativas superficiais, recorrendo sempre ? regra do octeto para descrever modelos de liga??es qu?micas. Os resultados sugerem que esses estudantes tiveram uma forma??o inadequada, no ensino m?dio e que os exames para ingresso nas gradua??es se fizeram segundo crit?rios pouco exigentes em termos de conhecimentos. As observa??es feitas levam ? conclus?o de que, para mudan?as futuras, ? necess?rio que escolas de ensino m?dio e dos per?odos iniciais nas universidades privilegiem a ado??o de m?todos pedag?gicos contextualizados, aplicando estrat?gias para superar o ensino memor?stico e superficial sobre Liga??es Qu?micas, o que, provavelmente, se aplica ao ensino de outros temas da Qu?mica

Ce travail porte sur la chimie de coordination des ligands ambiphiles combinant une base et un acide de Lewis. Le rôle que peut jouer l'acide de Lewis dans la sphère de coordination du métal est en particulier étudié par le biais d'une approche expérimentale et théorique. Le premier chapitre introduit le contexte et les principaux objectifs de ce travail. Le deuxième chapitre propose une étude des interactions métal->borane supportées par des ligands ambiphiles. Une description précise de l'interaction Au->B est proposée dans le cadre de la coordination de ligand diphosphine boranes. L'influence du fragment métallique sur la force de l'interaction M->B est également évaluée à travers l'étude d'une série isoélectronique de 7 complexes de triphosphine borane des métaux des groupes X et XI. Le troisième chapitre aborde les limites d'existence de ce type d'interaction en combinant ligands flexibles et métal peu basique. Un mode de coordination multi-centre est mis en évidence au sein d'une famille de complexes de Cuivre de mono-et di- phosphine boranes. Ce résultat met en lumière la capacité de ces ligands à adapter leur coordination en fonction de la demande électronique du métal. Le quatrième chapitre vise à déterminer l'influence du fragment acide de Lewis sur le mode de coordination des ligands ambiphiles. De façon inattendue, la complexation des ligands di- et tri- phosphine alanes conduit à des espèces zwittérioniques résultant d'une activation " totale " de la liaison M-X par l'acide de Lewis. La complexation des ligands phosphine gallanes conduit quant à elle à deux isomères de coordination, neutres et zwittérioniques, obtenus séparément ou en équilibre suivant le nombre de groupements donneurs du ligand
The present contribution deals with the coordination chemistry of ambiphilic ligands, featuring both Lewis base and Lewis acid sites. In particular, the role that can play the Lewis acid within the coordination sphere of the metal is investigated, thanks to combined experimental and computational analyses. The first chapter introduces the context and main goals of this work. The second chapter focuses on the study of metal->Lewis acid interactions supported by ambiphilic ligands. A description of the very nature of the Au->B interaction is proposed in the case of diphosphine borane complexes. The influence of the nature of the metallic fragment on the M->B interaction strength is also assessed through in depth study of seven isoelectronic triphosphine borane complexes. The third chapter tackled the limit of existence of M?B interactions by combining a weakly basic metal with flexible ligands. Multi-centre coordination modes are evidenced within a family of copper mono- and di- phosphine borane complexes. This study demonstrates the ability of ambiphilic ligands to adapt their coordination to the electronic demand of the metal centre. In the forth chapter, the influence of the Lewis acid nature on the coordination mode of ambiphilic ligands is investigated. Unexpectedly, the complexation of di- and tri- phosphine alane ligands to gold leads to zwitterionic complexes, resulting from the internal activation of the M-X bond by the Lewis acid. In contrast, the complexation of phosphine gallane ligands affords both neutral and zwitterionic coordination isomers, isolable or exchanging depending on the number of donor buttresses

Il s'agissait dans ce travail de préparer des composés fluorés de structure de type HTB ou hollandite au sein desquels la présence d'autres anions tels que OH- ou encore O2- viennent se substituer au fluor. Du point de vue structural, les réseaux présentent des canaux selon une seule direction de l'espace. La compétition entre fluoration et hydroxylation a fait l'objet d'une analyse détaillée, notamment par spectroscopie infra-rouge visant à expliquer la stabilité thermique de ces composés à anions mixtes. Enfin, l'acidité de surface, ainsi modifiée par rapport aux oxydes classiques, a été étudiée. Nous avons voulu dans ce travail mieux comprendre par une approche « chimie du solide », les propriétés de morphologie, de stabilité thermique et d'acidité des hydroxyfluorures et oxyhydroxyfluorures. La préparation et la caractérisation de nouveaux oxyhydroxyfluorures de fer et de chrome de structure hollandite a été présentée. Des études par diffraction neutronique couplées à une analyse par spectroscopie infra-rouge et la comparaison avec les hydroxyfluorures de type bronze de tungstène hexagonal nous ont permis de mieux appréhender leurs propriété physico-chimiques. Nos résultats nous ont permis de mettre en avant les rôles joués par les cations, les anions et la structure cristalline sur les différentes propriétés et notamment l'importance d'un nouveau paramètre, /r, caractéristique du cation, qui permet d'expliquer à la force des sites acides et la stabilité thermique de ces composés à structure ouverte. L'eau de constitution ainsi que la taux et la nature des groupements hydroxyles sont des paramètres clefs qui conditionnent la stabilité thermique et les propriétés acido-basiques du matériau final. Ce travail montre également l'influence des cations et du mode de synthèse sur ces caractéristiques.

The thesis introduction identifies the many theoretical approaches to myth, and reveals the need to find a new approach to the study of myth in the works and thought of C. S. Lewis. Most approaches to the study of myth are criticised by Lewis and his literary group of friends, known as the Inklings, as reductive. In contrast, Lewis proposed a more holistic, transcendent power of myth. The first chapter explores the specific importance of myth to Lewis' developing thought, from his early experiences of Norse myth to the development of his views in debate and through his involvement with the Inklings. Tensions and inconsistencies in Lewis' statements about myth are explored and the chapter culminates with Lewis' appreciation of myth in Christian faith, literature, and his realisation of myth as an object of contemplation. Chapter Two explores and contrasts the theories and approaches to myth of Ernst Cassirer with those of Lewis. Both thinkers are compared and areas of similarity and difference are identified, including their reactions to the problem of myth and Nazi ideology. Chapter Three applies the phenomenological traits, characteristics and principles of myth developed by Cassirer to Lewis' science fiction fantasy Perelandra. Mythical consciousness is evoked in this work through mythical images, the inner form of myth, and the type of worldview that threatens to engulf Ransom. We can observe the way that myth involves a sense of unification. Chapter Four identifies the symbolic form of myth in Till We Have Faces. The general characteristics of myth are explored and the inner form, or particular logic, of myth is revealed to actively form the mythical relations that dominate the lives of the characters. The function of myth as a form of thought is explored in the novel. Chapter Five delineates the symbolic form of myth within The Lion, the Witch, and the Wardrobe, with particular emphasis upon Lewis' handling of demonic and divine forces and the mythical concept of sacrifice and rebirth. In conclusion, a more holistic appreciation of myth in Lewis' works and thought is developed through the application of Cassirer's myth principles to Lewis' works. Apparently disparate aspects of myth are revealed to have a cohesive unity in mythical consciousness.

The primary goal of the research described in this thesis concern the synthesis, characterization and study of 1,8-bis(diarylmethylium)naphthalenediyl dications. Such dications have been prepared from the corresponding diols and have been fully characterized. Single crystals X-ray diffraction studies indicate that the two cationic centers of these derivatives are separated by 3.0 - 3.1 ??. The enforced proximity of the cationic centers intensifies the electron deficiency of these derivatives which behave as strong organic oxidants. As indicated by cyclic voltammetry, these dications undergo a two-electron reduction to afford the corresponding acenaphthenes. The newly formed C-C bond which links the former methylium are remarkably long (1.628-1.706 ??.) and can, in some instances, be oxidatively cleaved in the presence of acids. These dications can also be reduced chemically by reducing reagent, such as hydride, chloride, bromide and iodide. Remarkably, the reaction of 1,8-bis(diphenylmethylium)naphthalenediyl dication with fluoride anion results in the formation of a mono fluorinated cation which features an unsymmetrical C-F?C bridge between the former methylium centers. As indicated by 1H NMR spectroscopy, the structure of this cation is fluxional with the fluorine atom oscillating between the former methylium centers. Finally, this thesis also deals with the synthesis and study of 4,6-bis(dimesitylboryl)dibenzofuran and isoelectronic dications.

Il s'agissait dans ce travail de préparer différentes variétés cristallines d'hydroxyfluorures d'aluminium présentant des tailles nanométrique en vue d'application en catalyse. Pour ce faire une méthode solvothermale assistée par chauffage micro-ondes a été utilisée. La variation des paramètres de synthèse telle que la nature du précurseur cationique, le taux HF/Al ou encore l'utilisation de solvants organiques a permis la préparation de diverses formes cristallines présentant une pureté phasique et un aspect divisé. Trois matériaux ont ainsi été obtenus avec des structures dérivés du pyrochlore (Fd-3m), des bronzes de tungstène hexagonaux (Cmcm) et de type ReO3 (Pm-3m). L'utilisation de nombreuses techniques de caractérisations (DRX, RMN à l'état solide des noyaux 27Al, 19F et 1H, microscopie électronique, mesure de surface spécifique et spectroscopie infra-rouge) ont permis une analyse détaillée des solides préparés. L'impact structural des groupements OH sur la forme cristalline stabilisée a été mise en avant dans le cas du pyrochlore AlF1.7(OH)1.3 et de la forme HTB AlF2.6(OH)0.4. Dans le troisième composé, la stabilisation de molécule d'eau comme ligand a permis l'obtention du premier composé lacunaire dans la famille des fluorures d'aluminium. Ce dernier présente la formule générale suivante Al0.82-0.18F2.46(H2O)0.54. Le traitement d'un gel d'alkoxyfluorures d'aluminium par micro-ondes puis sous fluor gazeux a permis d'obtenir un matériau possédant une très grande surface spécifique (330 m2.g-1). L'étude des propriétés acides de ces matériaux par adsorption de molécules sondes détectées par FTIR a révélé une large gamme d'acidité de Lewis et de Brønsted. Finalement, l'influence de la surface spécifique sur le nombre de sites de Lewis forts a été mise en avant.

L’utilisation d’éléments de structures rigides gonflables doit permettre de réduire la masse, le volume en configuration pliée, ainsi que les coûts de fabrication d'éléments structuraux attachés aux satellites artificiels. Dans ce contexte, une technologie permettant le durcissement d’un composite multicouche par voie photochimique a été développée. La polymérisation de résines époxy amorcées par un complexe d'hexafluorophosphate cyclopentadiènyle-Fe(II)-arène a été retenue comme voie privilégiée pour la rigidification des structures. Des composés modèles ont d'abord été étudiés, sous un angle fondamental, dans le but d’examiner les étapes clef du processus de polymérisation photo-amorcée et de développer des méthodes quantitatives de suivi et de modélisation des phénomènes afin d’apporter des éléments de compréhension en vue d’une meilleure maîtrise du procédé. La contrainte de la faible teneur en composés volatils a ensuite été intégrée dans la recherche de nouvelles formulations compatibles avec un usage spatial, d’abord en se tournant vers des prépolymères époxy commerciaux. Afin d’obtenir les propriétés thermomécaniques désirées, il est apparu nécessaire de se tourner vers la synthèse sur mesure de copolymères réactifs à base de méthacrylate de glycidyle. Le point clef étant de contrôler les propriétés antagonistes d’une faible viscosité (poids moléculaires pas trop élevés) et d’une faible teneur en composés volatils. Divers outils d’ingénierie macromoléculaire ont été utilisés pour jouer sur l’architecture moléculaire, la teneur en fonctions réactives et les masses molaires
The development of original concepts such as inflatable and rigidizable structures for satellite appendages is driving the need for in-orbit rigidization technologies. Polymerization of composite in free space environment appears as one of the most promising processes among those envisioned to turn a foldable, inflatable structure into a rigid, load-bearing structure. In this context, the polymerization of epoxy resins photoinitiated by a Fe(II) cationic complex of methylnaphthalene was developed for the rigidization of inflatable structures. Model compounds were first studied from a fundamental point of view, in order to examine the key steps of the cationic photoinitiated polymerization reaction and to develop quantitative methods for monitoring and modeling the different steps of the curing reaction. The constraint of low content in volatile compounds in the uncured materials was then taking into account by considering commercial reactive prepolymers. For obtaining the desired thermomechanical properties, it become necessary to move towards the synthesis of reactive copolymers including glycidyle methacrylate units. The key point is to control the antagonistic properties of low viscosity (molecular weight not too high) and low content in volatile compounds. Various macromolecular engineering tools were used to obtain the desired architecture, with appropriate content in reactive functions and molecular weight

The synthesis and reaction chemistry of trans-(PPh3)2Pd(C6H4-4-I)(X) (X = I, OTf) is discussed. Treatment of trans- (PPh3)2Pd(C6H4- 4-I)(OTf) with bidentate Lewis-bases (N)N), such as pz, bipy, C5H4N-4-CN, (C6H4-4-CN)2 or C6H4-1,4-CN produces, depending on N)N, mono- or bimetallic species of type [trans- (PPh3)2Pd(C6H4-4-I)(N)N)]+ or [trans-(Ph3P)2(C6H4- 4-I)Pd N)N Pd- (PPh3)2(C6H4-4-I)]2+. These new complexes rearrange in the solution to give [trans-[(Ph3P)2Pd(C6H4-4-PPh3)(N)N)]2+ (N)N = C4H4N2, C5H4N-4-CN, NaC-4-C5H4N) and [trans-[(Ph3P)2(C6H4-4-PPh3)- Pd N)N Pd(PPh3)2(C6H4-4-PPh3)]4+ (N)N = C6H4-1,4-(CN)2, (C6H4-4- CN)2) along with {[(Ph3P)2(Ph3P-4-C6H4)Pd -(µ-I)]2}2+. The mechanism is elucidated. The latter species are rigid-rod structured. The preparation of mono- and homo-bimetallic palladium complexes of type [(Me(O)CS-4-C6H4)(PPh3)2Pd -(N)N)]+ and {[(Me- (O)CS-4-C6H4)(PPh3)2Pd]2(N)N)} 2+ (N)N = pz, bipy, C5H4N-4-CN, (C6H4-4-CN)2, C6H4-1,4-CN) is reported. The formation of the mono- or bimetallic species depends on the size of the Lewis bases N)N. The use of these molecules as molecular wire is discussed. The synthesis of homo-bimetallic palladium molecular wire complexes of type {[(Me(O)CS-4-C6H4-C6H4)(PPh3)2Pd]2(N)N)}2+ is described. The structural aspects of these complexes in the solid-state by single X-ray crystallography is discussed. The synthesis, characterization and electrochemical properties of a new series of homo-bimetallic palladium and platinum complexes of type [Me(O)CS-NCN-M]2(N)N) (NCN = [C6H2(CH2NMe2)2- 2,6)]-) is described. The effect of the para-substituent of the functionalized thio-acetyl NCN ligand on the electrochemical properties of the incorporated platinum center is discussed. The selective synthesis of acetylene and acyl-thiol endcapped heterobimetallic organometallic pi-tweezer of type {[Ti](µ-sigma,pi-CCR)2}CuS-C6H4-4-R ([Ti] = (eta5-C5H4SiMe3)2Ti; R = SiMe3; R = CCH,R = SC(O)Me) succeeds by the reaction of {[Ti](CCR)2}CuCH3 with equimolar amounts of Me(O)CSC6H4-4-CCH or the dithiol C6H4-1,4-(SC(O)Me)2. Binuclear (µ-RSe)(µ sigma,pi CCPh)Fe2(CO)6 can be prepared by treatment of RSe-CCPh (R = Et, nBu, Ph, 2,4,6-Me3C6H2) with Fe2(CO)9 in tetrahydrofuran at room temperature. In solution two isomers exist, depending on the position of the lone-pair of electrons present at selenium (axial or equatorial, respectively). Nucleophilic addition of P(OiC3H7)3 to (µ-RSe)- (µ -sigma,pi CCPh)Fe2(CO)6 affords vinylidene- and dimetallacylobutene- bridged complexes Fe2(CO)6(µ-Se(2,4,6-Me3C6H2)(µ-eta1C=C(Ph)- (P(OiC3H7)3) and [Fe2(CO)6(µ-Se(2,4,6-Me3C6H2)-(µ -eta1:eta1(Ph)C=C- {P(OiC3H7)3). The isolated complexes were characterized by multinuclear NMR (1H, 13C{1H}, and 31P{1H}, elemental analysis, FT-IR, and single x-ray crystallography
Ein Ziel der Arbeit war die Synthese von trans-(PPh3)2Pd(C6H4-4-I)(X) (X = I, OTf) und Untersuchungen zu dessen Reaktionsverhalten. Die Zugabe von zweizähnigen Lewis-Basen (N)N), wie z.B. pz, pz, bipy, C5H4N-4-CN, (C6H4-4-CN)2 oder C6H4-1,4-CN ergibt, abhängig von (N)N), mono- oder bimetallische Spezies vom Typ [trans-(PPh3)2Pd(C6H4-4-I)(N)N)]+ oder [trans-(Ph3P)2(C6H4-4-I)Pd N)N Pd-(PPh3)2(C6H4-4-I)]2+. Diese in Lösung instabilen Komplexe reagieren weiter zu [trans-[(Ph3P)2Pd(C6H4-4-PPh3)(N)N)]2+ (N)N = C4H4N2, C5H4N- 4-CN, NC-4-C5H4N) oder [trans-[(Ph3P)2(C6H4-4-PPh3)Pd N)N Pd(PPh3)2-(C6H4-4- PPh3)]4+ (N)N = C6H4-1,4-(CN)2, (C6H4-4-CN)2) zusammen mit {[(Ph3P)2(Ph3P-4- C6H4)Pd(µ-I)]2}2+. Der Mechanismus dieser Reaktionsfolge wurde aufgeklärt. Diese Komplexe besitzen eine starre, lineare Struktur, welche unter anderem mittels Röntgeneinkristallstrukturanalyse ermittelt wurde. Weiterhin wird über die Darstellung von mono- und homobimetallischen Palladium-Komplexen vom Typ [(Me(O)CS-4-C6H4)(PPh3)2Pd(N)N)]+ und {[(Me- (O)CS-4-C6H4)(PPh3)2Pd]2(N)N)}2+ (N)N = pz, bipy, C5H4N-4-CN, (C6H4-4-CN)2, C6H4-1,4-CN) berichtet. Die Bildung von homo- oder bimetallischen Spezies hängt von der Größe der Lewis-Base N)N ab. Die Anwendung dieser Moleküle als molekulare Drähte wird, zusammen mit der Festkörperstruktur zweier dieser Komplexe, diskutiert. Die Synthese von homobimetallischen Pd Komplexen vom Typ {[(Me(O)CS-4- C6H4-C6H4)(PPh3)2Pd]2(N)N)}2+ (molekulare Drähte) wird beschrieben. Die strukturellen Aspekte dieser Komplexe im festen Zustand werden diskutiert Die Synthese, Charakterisierung und elektrochemischen Eigenschaften einer neuen Serie von homobimetallischen Pd und Pt Komplexen vom Typ [Me(O)CSNCN- M]2(N)N) (NCN = [C6H2(CH2NMe2)2-2,6)]-) wird beschrieben. Der Effekt des para-Substituenten der funktionalisierten Thioacetyl-NCN Liganden auf die elektrochemischen Eigenschaften des komplexierten Pt wird diskutiert. Die selektive Synthese von Alkinyl- und Thioacetyl-funkionalisierten heterobimetallischen metallorganischen pi-Pinzetten-Komplexen vom Typ {[Ti](µ-sigma,pi-CCR)2}CuS-C6H4-4-CCH und {[Ti](µ-sigma,pi-CCR)2}CuS-C6H4-4-SC(O)Me ([Ti] = (eta5-C5H4SiMe3)2Ti; R = SiMe3, R = tBu) erfolgt durch die Reaktion von {[Ti](CCR)2}CuCH3 (R = SiMe3, R = tBu) mit äquimolaren Mengen an Me(O)CS-1- C6H4-4-CCH oder des Dithiols C6H4-1,4-(SC(O)Me)2. Im Vorgang dieser Reaktion wird Aceton gebildet. Zweikernige (µ-RSe)(µ sigma,pi CCPh)Fe2(CO)6 Komplexe können durch die Umsetzung von RSe-CCPh (R = Et, nBu, Ph, 2,4,6-Me3C6H2) mit Fe2(CO)9 in Tetrahydrofuran bei 20 °C dargestellt werden. In Lösung liegen, in Abhängigkeit von der Position des freien Elektronenpaares am Selen (axial oder äquatorial), zwei Isomere vor. Addition von P(OiC3H7)3 zu (µ-RSe)(µ sigma,pi CCPh)Fe2-(CO)6 ergibt Vinyliden- Fe2(CO)6(µ-Se(2,4,6-Me3C6H2)-(µ-eta1 C=C-(Ph)(P(OiC3H7)3) und Dimetallacyclobuten- verbrückte Komplexe der Art [Fe2(CO)6(µ-Se(2,4,6-Me3C6H2)-(µ-eta1:eta1- (Ph)C=C{P(OiC3H7)3). Die isolierten Komplexe wurden durch die Elementaranalyse, spektroskopisch (1H, 13C{1H}, 31P{1H} NMR; IR) und die Röntgeneinkristallstrukturanalyse charakterisiert

The present study is one of the first attempts undertaken to study English and Vietnamese news discourse on a contrastive basis. More specifically, it investigates the structure, the lexical and syntactic features of English and Vietnamese political news discourse. It is hoped that the results of the study may help the Vietnamese teacher and student to make better use of newspapers in the process of English language teaching and learning. In addition, it is hoped that the study may benefit the journalist, to some extent, because it is generally assumed that if the knowledge of news discourse structure, the linguistic features and the factors involved are professionally known and shared, this will facilitate news discourse production and comprehension. The study reveals two different strategies used by English and Vietnamese political news writers. English news writers predominantly employ the IP structure pattern whereas Vietnamese news writers employ BTN (Background-to-News). Lexically, English newspapers use more lively, vigorous language, metaphors, puns and hyperbole. In contrast, the occurrence of serious, formal language is a very pronounced feature of Vietnamese newspapers. This is the area where Vietnamese students of English often have difficulty, as is indicated by the survey. The greatest syntactic difference is sentence order, namely, English news stories often use S + V + (O) + (A) while their Vietnamese counterparts use A + S + V + (O) +. The other difference is that English news paragraphs are mostly single sentence paragraphs as disctinct from their multi-sentence Vietnamese ones. Chapter One is an introduction explaining the rationale, the methods, and the data for analysis, of the present study. Chapter Two is concerned with the theoretical background to the study. It deals with such concepts as cohesion, coherence, structure, relevance, text and discourse. Chapter Three provides a contrastive overview of English and Vietnamese newspapers, essentially in terms of ownership and the approach to news. Chapter Four examines the different structure patterns used by English and Vietnamese reporters and journalists. Chapter Five and Six study the different lexical and syntactic features of English and Vietnamese political news discourse, respectively. In chapter Seven, a comparison of English and Vietnamese political news discourse is given, which is based on the analyses presented in chapters Four, Five and Six. In addition, it presents the results of a survey of comprehension difficulty encountered by Vietnamese students studying English now at the University of Canberra, and looks at some discourse strategies involved in news discourse production and comprehension. The last chapter offers some implications for TEFL in Vietnam, which are based on the author's own experience and results of a survey. The author hopes that these implications may be of some help to the practising teacher as well as the student.

Doutoramento em Bioquímica
Helicobacter pylori is a bacterial pathogen that affects more than half of the world’s population with gastro-intestinal diseases and is associated with gastric cancer. The cell surface of H. pylori is decorated with lipopolysaccharides (LPSs) composed of three distinct regions: a variable polysaccharide moiety (O-chain), a structurally conserved core oligosaccharide, and a lipid A region that anchors the LPS to the cell membrane. The O-chain of H. pylori LPS, exhibits unique oligosaccharide structures, such as Lewis (Le) antigens, similar to those present in the gastric mucosa and are involved in interactions with the host. Glucan, heptoglycan, and riban domains are present in the outer core region of some H. pylori LPSs. Amylose-like glycans and mannans are also constituents of some H. pylori strains, possibly co-expressed with LPSs. The complexity of H. pylori LPSs has hampered the establishment of accurate structure-function relationships in interactions with the host, and the design of carbohydrate-based therapeutics, such as vaccines. Carbohydrate microarrays are recent powerful and sensitive tools for studying carbohydrate antigens and, since their emergence, are providing insights into the function of carbohydrates and their involvement in pathogen-host interactions. The major goals of this thesis were the structural analysis of LPSs from H. pylori strains isolated from gastric biopsies of symptomatic Portuguese patients and the construction of a novel pathogen carbohydrate microarray of these LPSs (H. pylori LPS microarray) for interaction studies with proteins. LPSs were extracted from the cell surface of five H. pylori clinical isolates and one NCTC strain (26695) by phenol/water method, fractionated by size exclusion chromatography and analysed by gas chromatography coupled to mass spectrometry. The oligosaccharides released after mild acid treatment of the LPS were analysed by electrospray mass spectrometry. In addition to the conserved core oligosaccharide moieties, structural analyses revealed the presence of type-2 Lex and Ley antigens and N-acetyllactosamine (LacNAc) sequences, typically found in H. pylori strains. Also, the presence of O-6 linked glucose residues, particularly in LPSs from strains 2191 and NCTC 26695, pointed out to the expression of a 6-glucan. Other structural domains, namely ribans, composed of O-2 linked ribofuranose residues were observed in the LPS of most of H. pylori clinical isolates. For the LPS from strain 14382, large amounts of O-3 linked galactose units, pointing to the occurrence of a galactan, a domain recently identified in the LPS of another H. pylori strain. A particular feature to the LPSs from strains 2191 and CI-117 was the detection of large amounts of O-4 linked N-acetylglucosamine (GlcNAc) residues, suggesting the presence of chitin-like glycans, which to our knowledge have not been described for H. pylori strains. For the construction of the H. pylori LPS microarray, the structurally analysed LPSs, as well as LPS-derived oligosaccharide fractions, prepared as neoglycolipid (NGL) probes were noncovalently immobilized onto nitrocellulosecoated glass slides. These were printed together with NGLs of selected sequence defined oligosaccharides, bacterial LPSs and polysaccharides. The H. pylori LPS microarray was probed for recognition with carbohydratebinding proteins (CBPs) of known specificity. These included Le and blood group-related monoclonal antibodies (mAbs), plant lectins, a carbohydratebinding module (CBM) and the mammalian immune receptors DC-SIGN and Dectin-1. The analysis of these CBPs provided new information that complemented the structural analyses and was valuable in the quality control of the constructed microarray. Microarray analysis revealed the occurrence of type-2 Lex and Ley, but not type-1 Lea or Leb antigens, supporting the results obtained in the structural analysis. Furthermore, the H. pylori LPSs were recognised by DC-SIGN, a mammalian lectin known to interact with this bacterium through fucosylated Le epitopes expressed in its LPSs. The -fucose-specific lectin UEA-I, showed restricted binding to probes containing type-2 blood group H sequence and to the LPSs from strains CI-117 and 14382. The presence of H-type-2, as well Htype- 1 in the LPSs from these strains, was confirmed using specific mAbs. Although H-type-1 determinant has been reported for H. pylori LPSs, this is the first report of the presence of H-type-2 determinant. Microarray analysis also revealed that plant lectins known to bind 4-linked GlcNAc chitin oligosaccharide sequences bound H. pylori LPSs. STL, which exhibited restricted and strong binding to 4GlcNAc tri- and pentasaccharides, differentially recognised the LPS from the strain CI-117. The chitin sequences recognised in the LPS could be internal, as no binding was detected to this LPS with WGA, known to be specific for nonreducing terminal of 4GlcNAc sequence. Analyses of the H. pylori LPSs by SDS-PAGE and Western blot with STL provided further evidence for the presence of these novel domains in the O-chain region of this LPS. H. pylori LPS microarray was also applied to analysis of two human sera. The first was from a case infected with H. pylori (H. pylori+ CI-5) and the second was from a non-infected control.The analysis revealed a higher IgG-reactivity towards H. pylori LPSs in the H. pylori+ serum, than the control serum. A specific IgG response was observed to the LPS isolated from the CI-5 strain, which caused the infection. The present thesis has contributed to extension of current knowledge on chemical structures of LPS from H. pylori clinical isolates. Furthermore, the H. pylori LPS microarray constructed enabled the study of interactions with host proteins and showed promise as a tool in serological studies of H. pyloriinfected individuals. Thus, it is anticipated that the use of these complementary approaches may contribute to a better understanding of the molecular complexity of the LPSs and their role in pathogenesis.
O Helicobacter pylori é uma bactéria patogénica que afeta mais de metade da população mundial com doenças gastrointestinais e está associado ao cancro gástrico. A superfície celular do H. pylori é decorada com lipopolissacarídeos (LPSs), que são constituídos por três regiões distintas: uma região polissacarídica variável (“O-chain”), um “core” oligossacarídico estruturalmente conservado e o lípido A, que ancora o LPS à membrana celular. A “O-chain” apresenta estruturas oligossacarídicas únicas, tais como os antigénios de Lewis (Le), que são semelhantes às presentes na mucosa gástrica e que estão envolvidas na interação com o hospedeiro. Glucanas, heptoglicanas e ribanas também constituem o “core” dos LPSs do H. pylori. Glicanas do tipo amilose e mananas também são referidas como integrantes de estirpes de H. pylori, possivelmente co-expressas com os LPSs. A complexidade dos LPSs do H. pylori tem dificultado o estabelecimento de uma relação entre a estrutura e a função em interação com o hospedeiro, que é crucial para o desenvolvimento de vacinas. Os microarrays de carboidratos são ferramentas recentes no estudo de antigénios e de novos ligandos oligossacarídicos, e que têm revelado a sua função em interações patogéniohospedeiro. O trabalho desta tese teve como objetivos principais a análise estrutural de LPSs de estirpes do H. pylori isoladas de biópsias gástricas de Portugueses sintomáticos e a construção de um microarray de LPSs do H. pylori (H. pylori LPS microarray) para estudos funcionais de interação com proteínas. Os LPSs foram extraídos da superfície celular de cinco isolados clínicos do H. pylori e de 1 estirpe de referência (NCTC 26695) pelo método fenol/água, fracionados por cromatografia de exclusão molecular e analisados por cromatografia em fase gasosa acoplada à espetrometria de massa. Os oligossacarídeos resultantes da hidrólise ácida parcial do LPS foram analisados por espetrometria de massa de electrospray. Para além de estruturas existentes no “core”, a análise estrutural, revelou a presença de antigénios de Le do tipo-2, Lex e Ley, e de sequências de resíduos de N-acetillactosamina (LacNAc), tipicamente encontrados em H. pylori. A identificação de resíduos de glucose ligados na posição O-6 nos LPSs das estirpes 2191 e NCTC 26695, indicou a presença de 6-glucanas. Outros domínios, nomeadamente ribanas, compostos por resíduos de ribofuranose ligados em posição O-2, foram identificados nos LPSs da maioria dos isolados clínicos. A presença de uma galactana (O-3 galactose), recentemente identificada noutra estirpe do H. pylori, foi também identificada para a estirpe 14382. Nos LPSs das estirpes 2191 e CI-117, a elevada quantidade de resíduos de Nacetilglucosamina (GlcNAc) ligados na posição O-4, sugeriu a presença de glicosídeos semelhantes à quitina (4GlcNAc) que, ao nosso conhecimento, ainda não foram descritos para o H. pylori. Para a construção do novo microarray, os LPSs analisados e os neoglicolípidos (NGLs) derivados de frações oligossacarídicas dos LPSs foram imobilizados não-covalentemente em suportes de nitrocelulose, juntamente com NGLs com sequências oligossacarídicas definidas, LPSs de outras bactérias e outros polissacarídeos. O microarray foi avaliado com proteínas de especificidade conhecida, que incluíram anticorpos monoclonais (mAbs) específicos para os antigénios de Le e estruturas relacionadas, um módulo de ligação a carboidratos (CBM), lectinas de plantas e os recetores do sistema imunitário DC-SIGN e Dectina-1. A análise com estas proteínas forneceu informação complementar à análise estrutural, para além de ter sido útil para o controlo de qualidade do microarray. A análise do microarray revelou a ocorrência de antigénios de Le do tipo-2, Lex e Ley, mas não do tipo-1, Lea e Leb, o que está de acordo com os resultados obtidos na análise estrutural. Os LPSs do H. pylori foram reconhecidos pela DC-SIGN, que é uma lectina conhecida por interagir com esta bactéria através dos antigénios de Le expressos nos seus LPSs. A lectina UEA-I, específica para -fucose, mostrou ser restrita para determinantes do grupo sanguíneo H do tipo-2 e para os LPSs das estirpes CI-117 e 14382. A ocorrência de antigénios do tipo H-2 e do tipo H-1 nos LPSs destas estirpes foi corroborada utilizando mAbs específicos. Os antigénios do tipo H-1 já tinham sido identificados em H. pylori, mas os do tipo H-2 foram identificados pela primeira vez neste estudo. Os LPSs do H. pylori foram também reconhecidos por lectinas com especificidade para oligossacarídeos de quitina (4-linked GlcNAc). A STL, que mostrou uma ligação restrita aos tri- e pentassacarídeos, reconheceu distintivamente o LPS da estirpe CI-117, que poderão ser internas, dada a ausência de ligação detectada pela lectina WGA, com especificidade para terminais não redutores 4GlcNAc. A análise dos LPSs do H. pylori por SDS-PAGE e Western blot com a STL apontou para a presença destas estruturas na “O-chain” deste LPS. O microarray dos LPSs do H. pylori foi utilizado para a análise do soro de um indivíduo infetado com H. pylori (H. pylori+ CI-5), e mostrou um aumento na detecção de IgGs para os LPSs de H. pylori no soro H. pylori + quando comparado com o soro de um indivíduo não-infetado (H. pylori-). A resposta observada foi específica para o LPS do isolado da estirpe CI-5, causadora da infeção. O trabalho desenvolvido nesta tese contribuiu para a extensão do conhecimento estrutural dos LPSs dos isolados clínicos do H. pylori. A construção do microarray dos LPSs de H. pylori permitiu o estudo de interações com proteínas do hospedeiro, e mostrou ser útil na análise serológica de indivíduos infetados com esta bactéria. Deste modo, espera-se que o uso destas técnicas complementares possa contribuir para uma melhor compreensão da complexidade molecular dos LPSs e do seu papel na patogenicidade.

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ABSTRACT The aim of this paper is to discuss about the partnership organ in the limited partnership, not putting aside the changes that happened with the beginning of the Civil Code of 2002 and the institutional way that the new law caused in these juridical institutes. This kind of partnership has great importance in the Brazilian juridical system as it represents the most used kind of partnership. This paper is divided into three chapters: the fist one characterizes the new administrative structure in the limited partnership as the identification of the new structures with the meaningful changes in the status of the new administrator and the instruments of designation and its new responsibilities, mainly the ultra vires theory. The second chapter discusses about the newness of legislative forecast of the fiscal council to the limited partnership in all its aspects, even if it is a facultative organ. In the last chapter the partnership deliberations were analyzed, mainly the new partner assembly, above all in the partnerships with more than ten partners and the way the legislator wrote down the conduction of this institute. To sum up, the organs are really important in the partnership life so that without them the partnership could not practice the business acts. However, the focus is not the administrative aspects but the juridical ones, the way through the referred organs practice these acts related to the validity and its manifestations.
O objetivo desse trabalho é discorrer sobre os órgãos societários na sociedade limitada, tendo em vista, as modificações ocorridas com a entrada em vigor Código Civil de 2002 e a forma institucional que a nova lei começou a imprimir nestes institutos jurídicos, visto a importância que este tipo societário representa no ordenamento jurídico brasileiro por representar o tipo mais usado pelas sociedades regularmente constituídas. O presente trabalho está dividido em três capítulos: o primeiro, cuja proposta é a caracterização da nova estrutura administrativa na sociedade limitada coma a identificação desta nova estrutura com as mudanças significativas quanto ao status do novo administrador e os instrumentos de designação e suas novas responsabilidades principalmente a teoria ultra vires . O segundo trata da novidade da previsão legislativa do conselho fiscal para a sociedade limitada em todos os seus aspectos, mesmo sendo um órgão facultativo caso previsto as previsões legislativas terão desdobramentos neste órgão societário. Por fim no último capítulo trabalhamos com as deliberações societárias, principalmente a novidade da assembléia de sócios, sobretudo nas sociedades com mais de dez sócios dando ênfase à forma como o legislador prescreve a condução deste instituto. Conclui-se que a importância dos órgãos na vida societária e de tal maneira que sem eles a sociedade não conseguiria praticar os atos da vida negocial, no entanto, o nosso enfoque não é no mérito de tais atos que na maioria das vezes interessa mais ao aspecto administrativo, mas pelo aspecto jurídico principalmente pela forma como o ato é praticado pelos referidos órgãos que pela maneira conduzida terão conseqüências no mundo jurídico principalmente com relação à validade de suas manifestações.

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CNPq
Neste trabalho é considerado o problema de Riemann para um sistemas de leis de conservação modelando a recuperação de óleo de um reservatório petrolífero pela injeção de uma mistura do tipo água e gás. supondo que o mesmo contenha inicialmente uma mistura do tipo água e óleo. A partir da teoria de Leis de Conservação é determinada a solução do problema de Riemann considerando os várias casos possíveis para dados de produção. Para cada um desses dados de produção são considerados todos os casos possíveis de injeção da mistura água/gás. Para cada caso de produção é mostrada a existência de estados especiais de injeção separando construções distintas de soluções no espaço de estados. Além disso, entre esses estados especiais de injeção um deles é crítico, no sentido que a solução é dada de duas ou três maneiras distintas no espaço de estados, porém representando a mesma solução no espaço físico - xt. Em geral a solução do problema de Riemann consiste de duas ondas separadas por um estado intermediário constante quando o dado de produção está próximo de situações extremas, em que a saturação inicial da água ou do óleo é maximal. Para estados de produção com uma proporção mais homogénea da mistura de água e óleo a solução pode consistir de até três ondas para alguns casos de injeção de uma mistura contendo uma proporção maior de gás do que de água. Nesses casos uma onda não clássica, i. e. uma onda transicional, deve ser usada.
In this work we consider the Riemann probíem for a system of conservation laws modeling the oil recovery for a three-phase flow in a porous médium by the injection of a mixture of water and gas in a reservoir whieh is initially filled with a mixture of water and oil. Using the theory of conservation laws, the solution of the Rieman problem is determined considering ali possibilities for the production data. For each of these production data. ali possible cases for the injected gas/ water mixture are considered as well. For each production case it is shown the existence of some special injection data separating distinct constmctions of Solutions in the state space. Moreover, among these special injection data one of them is criticai in the sense that the wave sequence that describes the solution can be represented by two or three distinct paths in the state space, but consisting of the same solution in the physical space - xi. In general the solution of the Riemann problem consists of a sequence of two waves separated by one intermediate constant state when the production data are closed to the extreme situations where the initial water or oil saturations are maximal. For production data with a more homogeneous initial water and oil proportion, the solution may consists up to three waves separated by two constant intermediate states for some injected mixtures containing a hígher proportion of gas than water. In such cases a nonelassical wave, i. e. a transitional wave, must be used.

Uppsatsen undersöker hur ”SOU 2016:11 Olika vägar till föräldraskap” formulerar problemet med surrogatmoderskap, vilka subjektspositioner som kan urskiljas i utredningen och analyserar den ut ett kritiskt postkolonialt feministiskt perspektiv.   Utredningen utgår ifrån mänsklig värdighet, autonomi och barnets bästa vilket uppsatsen belyser får konsekvenser för hur problemet med surrogatarrangemang porträtteras olika beroende på om surrogatmodern och barnet är från det globala syd eller det globala nord. Utgångspunkterna är centrala när surrogatmodern och barnet från det globala nord lyfts men får inte samma roll gällande surrogatmodern och det barn hon föder. Vidare undersöks hur subjektspositioner formuleras utifrån emotionell/icke-emotionell, sårbar/icke-sårbar, skyddsvärd/icke-skyddsvärd och blottlägger hur den svenska surrogatmodern och det inrikesfödda barnet konstrueras som emotionella, sårbara och skyddsvärda vilket skiljer sig från hur den utländska surrogatmodern och det utrikesfödda barnet konstrueras. Dessa omges att tystnad vilket får konsekvenser för hur de porträtteras och för vilka åtgärder som föreslås.   Uppsatsen bidrar till en utveckling av tidigare forskning med ett tillägg av nyckelordet skyddsvärd för att undersöka konstrueringen av surrogatmödrar. Uppsatsen visar att begreppet är relevant genom att materialet visat på delvis konstuering av emotionell och sårbar men inte skyddsvärd och att detta påverkat resultat och åtgärder. Vidare stärker uppsatsen tidigare forskning som menar att utgångspunkten mänsklig värdighet verkar för en avhumanisering av surrogatmödrar från det globala syd samt att synen på biologi varierar beroende på var ett barn föds. Uppsatsen bygger vidare på tidigare forskning som menar att uttryckt rationalitet och brist på emotion resulterar i en avhumanisering, genom att blottlägga hur det kan räcka med att subjektspositionerna möts av tysthet för att uppnå samma resultat. Detta arbete belyser hur olika subjektspositioner framställs olika i den statliga utredningen och hur koloniala idéer hänger kvar och påverkar underlag till svensk lagstiftning, samt blottlägger vilka konkreta konsekvenser detta kan få för lagförslag och för surrogatmödrar i det globala syd samt de barn de föder.

abstract: This dissertation explores the megamachine, a prominent metaphor in American humanist and philosopher of technology, Lewis Mumford's Myth of the Machine series. The term refers critically to dynamic, regimented human capacities that drive scientific and technical innovation in society. Mumford's view of the nature of collectives focuses on qualities and patterns that emerge from the behavior of groups, societies, systems, and ecologies. It is my aim to reenergize key concepts about collective capacities drawn from Lewis Mumford's critique of historical and modern sociotechnical arrangements. I investigate the possibility of accessing those capacities through improved design for Technology Assessment (TA), formal practices that engage experts and lay citizens in the evaluation of complex scientific and technical issues. I analyze the components of Mumford's megamachine and align key concerns in two pivotal works that characterize the impact of collective capacities on society: Bruno Latour's Pasteurization of France (1988) and Elias Canetti's Crowds and Power (1962). As I create a model of collective capacities in the sociotechnical according to the parameters of Mumford's megamachine, I rehabilitate two established ideas about the behavior of crowds and about the undue influence of technological systems on human behavior. I depart from Mumford's tactics and those of Canetti and Latour and propose a novel focus for STS on "sociotechnical crowds" as a meaningful unit of social measure. I make clear that Mumford's critique of the sociotechnical status quo still informs the conditions for innovation today. Using mixed mode qualitative methods in two types of empirical field studies, I then investigate how a focus on the characteristics and components of collective human capacities in sociotechnical systems can affect the design and performance of TA. I propose a new model of TA, Emergent Technology Assessment (ETA), which includes greater public participation and recognizes the interrelationship among experience, affect and the material in mediating the innovation process. The resulting model -- the "soft" megamachine --introduces new strategies to build capacity for responsible innovation in society.
Dissertation/Thesis
Doctoral Dissertation Human and Social Dimensions of Science and Technology 2014

Brønsted and Lewis acid sites located within microporous solids catalyze a variety of chemical transformations of oxygenates and hydrocarbons. Such reactions occur in condensed phases in envisioned biomass and shale gas upgrading routes, motivating deeper fundamental understanding of the reactivity-determining interactions among active sites, reactants, and solvents. The crystalline structures of zeolites, which consist of SiO₄ tetrahedra with isomorphously-substituted M⁴⁺ (e.g., Sn⁴⁺, Ti⁴⁺) as Lewis acid sites, or Al³⁺ with charge-compensating extraframework H⁺ as Brønsted acid sites, provide a reasonably well-defined platform to study these interactions within confining voids of molecular dimension. In this work, gas-phase probe reactions that afford independent control of solvent coverages are developed and used to interpret measured rate data in terms of rate and equilibrium constants for elementary steps, which reflect the structure and stability of kinetically relevant transition states and reactive intermediates. The foundational role of quantitative kinetic information enables building molecular insights into the mechanistic and active site requirements of catalytic reactions, when combined with complementary tools including synthetic approaches to prepare active sites and surrounding environments of diverse and intended structure, quantitative methods to characterize and titrate active sites and functional groups in confining environments, and theoretical modeling of putative active site structures and plausible reaction coordinates.

This work describes a special kind of story about the journey there and back again or journey to gain experience. The nature of this narrative is given by the presence of several key points: the existence of primary and secondary world, wandering throughout secondary world, the transformation of a hero and a reader, homecoming. Presented definition of the story is the starting point from which are being searched connections with the professional disciplines of social work and ethics. In social work the diagram of these trips back and forth presents acquiring an expertise in various scientific fields. For plane of ethics it is particularly significant credibility of the moment from this journey back and forth when the story of the hero and the reader becomes a good (or bad) story positive or negative.

This MA thesis is concerned with the comparison of two Czech translations of C. S. Lewis' novel The Chronicles of Narnia: The Lion, the Witch and the Wardrobe. The thesis is divided into two parts: theoretical and practical. The first part concentrates on the description of the author's and translators' life as well as the background of creating the novel and its translations. One part deals with the film adaptations of the book. Then there are described individual techniques and methods of translation and its analysis. The second part analyses the book in general. Names used in the book, titles of chapters, selected passages and special idioms are analyzed in detail. It deals with different approaches of each translator and examines the usage of words, sentence structures and their text style. The thesis tries to compare and analyze all three texts in order to come up with the sufficient justification or disprove of all used items. Key words Novel, translation, translator, author, analysis, comparison, usage of words, sentence structures, text style, methods of translation, justification, disprove.