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Chin, Melanie Soo, and m. chin@cqu edu au. "Towards a Reinterpretation of the Radical Theory of Associative Rings Using Base Radical and Base Semisimple Class Constructions." Central Queensland University. Computer Science, 2004. http://library-resources.cqu.edu.au./thesis/adt-QCQU/public/adt-QCQU20050411.102928.
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This research aims to refresh and reinterpret the radical theory of associative rings using the base radical and base semisimple class constructions. It also endeavours to generalise some results about ideals of rings in terms of accessible subrings. A characterisation of accessible subrings is included. By applying the base radical and base semisimple class constructions to many of the known results in established radical theory a number of gaps are uncovered and closed, with the goal of making the theory more accessible to advanced undergraduate and graduate students and mathematicians in related fields, and to open up new areas of investigation.
After a literature review and brief reminder of algebra rudiments, the useful properties of accessible subrings and the U and S operators independent from radical class connections are described. The section on accessible subrings illustrates that replacing ideals with accessible subrings is indeed possible for a number of results and demonstrates its usefulness.
The traditional radical and semisimple class definitions are included and it is shown that the base radical and base semisimple class constructions are equivalent. Diagrams illustrating the constructions support the definitions. From then on, all radical and semisimple classes mentioned are understood to have the base radical and base semisimple class form. Subject to the constraints of this work, many known results of traditional radical theory are reinterpreted with new proofs, illustrating the potential to simplify the understanding of radical theory using the base radical and base semisimple class constructions. Along with reinterpreting known results, new results emerge giving further insight to radical theory and its intricacies. Accessible subrings and the U and S operators are integrated into the development. The duality between the base radical and base semisimple class constructions is demonstrated in earnest.
With a measure of the theory presented, the new constructions are applied to examples and concrete radicals. Context is supported by establishing the relationship between some well-known rings and the radical and related classes of interest.
The title of the thesis, Towards a Reinterpretation of the Radical Theory of Associative Rings Using Base Radical and Base Semisimple Class Constructions, reflects the understanding that reinterpreting the entirety of radical theory is beyond the scope of this work. The conclusion includes an outlook listing further research that time did not allow.
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Rahim, Medhat H., Radcliffe Siddo, and Moushira Issa. "Tangram-base Problem Solving in Radical Constructivist Paradigm: High School Student-Teachers Conjectures." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-83015.
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Sanii, Laurie Shireen. "The effect of terminal base identity on radical cation injection into the DNA duplex." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/29377.
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Polenz, Ingmar, Andreas Laue, Tamas Uhrin, Tobias Rueffer, Heinrich Lang, Friedrich Schmidt, and Stefan Spange. "Thermally cleavable Imine Base / Isocyanate Adducts and Oligomers suitable as Initiators for Radical Homo- and Copolymerization." Universitätsbibliothek Chemnitz, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-152196.
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The addition of isocyanates to C=N double bonds of imines gives triazindione heterocycle structures; their thermal properties are reported. Mono-isocyanates were used to form 2:1 adducts with the imine bases 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) and 2-tert-butyl-1,1,3,3-tetramethylguanidine (tBuTMG). A 2:1 stoichiometry of the adducts was proven by NMR and IR spectroscopy, and single crystal X-Ray diffraction; certain cleavage temperatures (70 and 160 °C) were measured. Thermal analysis (TG-MS) of adducts indicates the release of free isocyanate during adduct cleavage. Furthermore, a new class of step-growth oligomers (MN = 750–7,000 g∙mol–1) composed of multi-functional isocyanates and these imine bases was introduced. Their systematic spectroscopic and thermal analysis is shown revealing the similarity in their chemical properties to the 2:1 adducts. Radical homo- and copolymerization of acrylates is initiated by the meta-stable adducts and oligomers of this work; the generation of novel telomeric block-copolymer architectures composed of polyacrylate and oligourea building blocks is demonstratedDieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich
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Cassas, Fernando Albregard. "O acompanhamento terapêutico como prática do analista do comportamento: uma caracterização histórica com base no behaviorismo radical." Pontifícia Universidade Católica de São Paulo, 2013. https://tede2.pucsp.br/handle/handle/16716.
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Previous issue date: 2013-07-05The work presented here is motivated by a clinical intervention that began to be practiced by behavior analysts in Brazil in the early 1990s. This form prioritizes the work in the natural environment and, therefore, more likely to act directly on controlling contingencies of client behavior. This type of control seems to have established in the literature, a polarization between Therapeutic Accompaniment (TA) and the clinical based on the greater or lesser ability to control to be undertaken on the client behavior. The research presented here aims to resume and analyze the therapeutic practices of radical behaviorist base in order to establish a comparison between them and the TA, thus define whether it is possible to assert the existence of this polarization. Four sets of papers were analyzed: bases of behavior therapy: publications Skinner and Ferster about therapy, the Behavior Modification; literature on the following therapeutic approaches: Functional Analytic Therapy, Acceptance and Commitment Therapy, Behavioral Activation, the literature on the brasilian therapeutic proposals: Analytical Behavioral Therapy, Therapy of Contingencies of Reinforcement, Pragmatic Behavioral Psychotherapy and Molar and Self Therapy, beyond literature about the TA. To compose this analysis, four analytical categories were developed: core concepts for the diagnosis, intervention strategies, effectiveness and generality. The analysis of the studies cited showed that the polarization in the terms formulated above, is not true because all proposed schedule forms to ensure the generalizability of the results. Could be defined, however, the existence of a "minimum repertoire client". This concerns the modeling repertoire of verbal behavior that will allow the client to modify alone, the environment itself. And that is the reason for this study in a natural environment where the client does not have the repertoire to modify their own environment independently, the therapist operates the changing client environment in order to build a better learning condition for that client. From this, suggestions for future research are made at the end of the work
A tese aqui apresentada é motivada por um trabalho de intervenção clínica que começou a ser praticado por analistas do comportamento brasileiros no início da década de 1990. Essa forma prioriza o trabalho em ambiente natural e, com isso, maior chance de atuar diretamente nas contingências controladoras do comportamento do cliente. Esse tipo de controle parece ter estabelecido, na literatura da área, uma polarização entre o Acompanhamento Terapêutico (AT) e o consultório com base na maior ou menor possibilidade de controle a ser assumido sobre o comportamento do cliente. A pesquisa aqui apresentada se propõe a resgatar e analisar as práticas terapêuticas de base behaviorista radical com vistas a estabelecer uma comparação entre elas e o AT para, assim, definir se é possível afirmar a existência dessa polarização. Para isso, quatro conjuntos de trabalhos foram analisados: bases da terapia comportamental: publicações de Skinner e de Ferster respeito da terapia, e sobre a Modificação de Comportamento; a literatura sobre as seguintes propostas terapêuticas: Functional Analytic Therapy, Acceptance and Commitment Therapy, Behavioral Activation; a literatura sobre as propostas terapêuticas nacionais: Terapia Analítico‐ comportamental, Terapia por Contingências de Reforçamento, Psicoterapia Comportamental Pragmática e Terapia Molar e de Autoconhecimento, além da literatura acerca do Acompanhamento Terapêutico. Para compor essa análise, foram desenvolvidas quatro categorias analíticas: conceitos centrais para o diagnóstico, estratégias de intervenção, efetividade e generalidade. A análise dos trabalhos citados apontou que a polarização, nos termos formulados acima, não acontece, pois todas as propostas programam formas garantir a generalização dos resultados. Foi possível definir, no entanto, a existência de um repertório mínimo de cliente . Esse repertório diz respeito a modelagem de comportamento verbal que permitirá ao cliente modificar, sozinho, o próprio ambiente. E essa é a justificativa do trabalho em ambiente natural, quando o cliente não tem repertório para modificar o seu próprio ambiente de forma independente, o terapeuta opera mudando o ambiente do cliente de maneira a construir uma condição de aprendizagem melhor para esse cliente. A partir disso, sugestões para pesquisas futuras são feitas ao final do trabalho
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Baguenard, Céline. "Synthèse et caractérisation d’architectures macromoléculaires complexes à base d’un bloc « stimuli-responsive »." Thesis, Lyon, INSA, 2012. http://www.theses.fr/2012ISAL0009.
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Les polymères répondant au pH ou à la température deviennent hydrophobes à partir d’un pH ou d’une température critique. Associés à un bloc polymère hydrophile, ils peuvent former des micelles réversibles en solution aqueuse en réponse à un stimulus. Cette thèse décrit principalement la synthèse par polymérisation radicalaire contrôlée de copolymères à blocs triple hydrophiles de type ABC ou ACB, composés d’un bloc très hydrophile (PEO, bloc A), d’un bloc répondant à la température et au pH (PDMAEMA, bloc B) et d’un bloc cationique (PDMAEMAquat, bloc C). Leur caractérisation par chromatographie d’exclusion stérique en phase aqueuse s’est révélée peu concluante ; c’est pourquoi nous les avons analysés par RMN diffusionnelle. D’autre part, l’auto-assemblage en solution aqueuse de ces copolymère triblocs en fonction du pH et de la température a été étudié par RMN 1H et par DLS. Par ailleurs, le bloc C, cationique, forme un complexe hydrophobe avec un polymère chargé négativement (PSS). Les objets résultant de cette complexation entre le dernier bloc du tribloc ABC et le PSS ont été caractérisés par RMN 1H, par DLS, par RMN diffusionnelle et par TEM. Leur comportement en solution aqueuse en fonction du pH et de la température a également été abordéPH- or temperature-responsive polymers become hydrophobic from a critical pH or temperature. When they are associated to a hydrophilic block, they may respond to a stimulus by forming reversible micelles in aqueous solution. This thesis mainly deals with the synthesis by controlled radical polymerization of ABC- or ACB-type triple hydrophilic block copolymers, based on a highly hydrophilic block (PEO, A-block), a pH- and temperature-responsive moiety (PDMAEMA, B-block) and a cationic sequence (PDMAEMAquat, C-block). As their characterization by SEC in aqueous phase was not conclusive, they were therefore analyzed by diffusional NMR. In addition, their self-assembly in aqueous solution depending on pH or temperature was studied by 1H NMR and DLS. Furthermore, the cationic C-block form a so-called polyelectrolyte complex with a negatively charged polymer (PSS). Objects resulting from the complexation between the last block of ABC-triblock and PSS were characterized by 1H NMR, DLS, diffusional NMR and TEM. Their behavior in aqueous solution was also investigated depending on pH and temperature
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Michel, Eléonore. "Recouvrements à base de dextrane pour applications médicales." Thesis, Sorbonne Paris Cité, 2016. http://www.theses.fr/2016USPCD086/document.
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L’ingénierie des biomatériaux a connu un essor prodigieux ces dernières décennies passant de matériaux simples à des structures plus complexes, particulièrement dans le domaine cardiovasculaire. Cette évolution découle de la nécessité des biomatériaux de permettre la synergie de différentes propriétés, dépendantes de leurs fonctions, qui ne sont pas forcément toutes compatibles. Historiquement, les premiers matériaux utilisés dans la conception de dispositifs médicaux étaient ceux présentant le meilleur compromis entre les propriétés physico-chimiques, mécaniques et biologiques que nécessitait leur application. Cependant, il se peut que le dispositif possède les bonnes propriétés physico-chimiques ou mécaniques, mais que sa biocompatibilité soit insuffisante induisant ainsi des complications cliniques. Afin d’améliorer ces propriétés biologiques tout en conservant les propriétés de volume du matériau, une solution est d’en modifier la surface. L’utilisation d’un revêtement permet alors de moduler la réponse biologique à l’interface biomatériau-hôte et de diminuer les effets indésirables. Ces revêtements sont optimisés selon deux critères principaux : la réponse biologique et la réponse mécanique. Pour la réponse biologique, les deux approches principales sont de mettre au point des revêtements proactifs qui engendrent l’adhérence, laprolifération ou la migration cellulaire, ou passifs, qui, principalement, sont inertes et empêchent l’adhérence de composés biologiques. Des revêtements plus complexes utilisent les deux approches permettant l’adhérence spécifique de certainescellules tout en empêchant l’adhérence d’autres composants biologiques. Cette pratique est très utile pour lutter contre la resténose, complication survenant après opération de l’athérosclérose qui obstrue les vaisseaux sanguins. Une pratique courante est la pose d’un stent qui permet d’ouvrir l’artère de nouveau et de rétablir le flux sanguin. Le phénomène de resténose obstrue de nouveau le vaisseau sanguin, majoritairement par la prolifération incontrôlée de cellules musculaires lisses. La recherche sur les revêtements contre la resténose vise à inhiber la prolifération de ces cellules tout en facilitant la ré-endothélialisation. Les revêtements permettraient alors, à la fois de favoriser l’adhérence et la prolifération de cellules endothéliales et de limiter celles des cellules musculaires lisses à la surface du stent ou en limitant toute adhérence non-spécifique. Il a été démontré lors d’études précédentes qu’un copolymère à base de dextrane et de poly(méthacrylate debutyle) (PBMA) répondait à ces critères biologiques et qu’il possédait en plus une bonne résistance à la déformation, paramètre important lié à la déformation induite lors de l’implantation d’un stent. L’approche de ce projet était d’utiliser ce copolymère comme revêtement de stent et d’en améliorer la stabilité à long terme en formant des liens covalents avec le substrat. Pour ce faire, cela nécessitait l’activation de la partie dextrane du copolymère afin de pouvoir le greffer au substrat. Il était important de vérifier pour chaque étape l’influence des modifications effectuées sur les propriétés biologiques et mécaniques des matériaux obtenus, mais aussi d’un point de vue de la chimie, l’influence que cette modification pouvait induire sur la réaction decopolymérisationThe last decades have witnessed the remarkable growth of biomaterial science and engineering field, especiallyfor cardiovascular applications, for which devices have evolved from simple material to complex structures.This development has stemmed from the necessity for biomaterials to exhibit different properties, related totheir function, which are not always inherently compatible. Historically, the first materials selected for medicaldevices conception were the ones exhibiting the best compromise between all the physicochemical, mechanicaland biological requirements. Nevertheless, while physicochemical and mechanical properties are often handilycombined, the development of materials which also possess suitable biological properties have proved to bemuch more challenging, leading to clinical complications.Surface modification represents a valid solution to improve the biological performances of medical deviceswhile maintaining the bulk properties of the material. Biomaterial coatings may modulate the biologicalresponse at the biomaterial-host interface and decreases the undesirable effects. Coatings have been optimizedin regards to two main aspects: the biological response and the mechanical response. For the biologicalresponse, the two main approaches consist in 1) inducing cell adhesion, proliferation or migration with proactivecoatings and 2) using inert material, mostly, and avoiding the adhesion of any biological componentswith passive coatings.More complex coatings include the two approaches, allowing the adhesion of a specific type of cell whilerepelling other biological components adhesion. This method has been very useful against the restenosisphenomenon which obstructs blood vessels. A common practice is vessel stenting, a procedure that enables thereopening of the vessel and the restoration of the blood flow. Restenosis causes the new narrowing of the vessel,mostly due to uncontrolled smooth muscle cell proliferation. Researchers looked for coatings capable oflimiting the restenosis occurrence by inhibiting this cell proliferation along with facilitating the reendothelialization.Thus, the coatings would be able to improve endothelial cells adhesion and proliferation andto inhibit smooth muscle cells ones as well as avoiding non-specific adhesion.Previous studies showed that a copolymer made of dextran and poly(butyl methacrylate) (PBMA) demonstratedsuch biological properties and a good resistance to deformation, which is an important parameter related to thedeformation implied in a stent implantation. In this work, the approach was to use this copolymer as a stentcoating and to increase its long-term stability by providing covalent bonds with the substrate. To do so, thedextran part of the copolymer firstly needed to be activated in order to be grafted to the surface. Thus, it wasimportant to ascertain the influence of the multiple modifications on the biological and mechanical propertiesof the resulting materials at each step, but also towards a chemical point of view, the influence that thesemodifications may have on the subsequent copolymerization
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Chalasani, Sri Lakshmi. "RESOLUTION OF PROXIMAL OXIDATIVE BASE DAMAGE AND 3′-PHOSPHATE TERMINI FOR NONHOMOLOGOUS END JOINING OF FREE RADICAL-MEDIATED DNA DOUBLE-STRAND BREAKS." VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5237.
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Clustered damage to DNA is a signature mark of radiation-induced damage, which involves damage to the nucleobases and/or DNA backbone. Double-strand breaks created by damaging agents are detrimental to cell survival leading to chromosomal translocations. Normal cells employ Non-homologous end-joining because of its faster kinetics, to suppress chromosomal translocations. However, the presence of complex DNA ends constitutes a significant challenge to NHEJ. Location of Thymine glycol (Tg) at DSB ends was a potential hindrance to end joining. The substrate with Tg at the third position (Tg3) from the DSB joined better than when present at the fifth position (Tg5). However, hNTH1 assay showed Tg5 to be a better substrate than Tg3 for BER, potentially explaining the increased Tg removal and decreased end joining of Tg5 in extracts. Nonetheless, there appeared to be no preference in the susceptibility of 5’-Tg substrates with Tg at the second and third positions from DSB ends.
Polynucleotide kinase phosphatase is crucial in restoring the 3′ hydroxyl, and 5′ phosphate ends at strand breaks. No other enzyme is known to possess PNKP’s activity in mammalian cells at DSBs. Experiments done with PNKP knockout cells have shown some activity similar to PNKP, which appeared to be a part of NHEJ and was not pharmacologically inhibited by PNKP inhibitor. Additionally, core NHEJ factors XRCC4 and XLF influenced the activities of PNKP.
Overall, these experiments suggest that Tg repair is dependent on the position from DSB and an alternative enzyme processes 3′- PO, and 5′-OH ends.
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Álvares, Antonio Carlos Teixeira. "Inovação horizontal: um modelo ambidestro de gestão da inovação com base em um caso brasileiro." reponame:Repositório Institucional do FGV, 2018. http://hdl.handle.net/10438/25712.
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Esta pesquisa trata da questão dos efeitos provocados pela busca da inovação a partir de todas as pessoas da organização, particularmente da possibilidade da organização se tornar inovadora, assim entendido como capaz de produzir sistematicamente inovações de qualquer natureza e magnitude. Tal questão é relevante pois a inovação a partir de todas as pessoas de uma organização, praticamente não tem sido estudada pelos especialistas em inovação. Apesar de muito abordada pelo movimento de qualidade no tema de melhoria continua via sistemas de sugestões do tipo kaizen. A denominação Inovação Horizontal foi criada pelo autor para designar as inovações que se originam a partir de todos os funcionários da organização, usualmente a partir de programas internos de sugestões. Os sistemas internos de sugestões produzem basicamente inovações incrementais, denominadas pelos especialistas em qualidade como melhorias contínuas. Alguns autores apresentaram no passado a teoria de que novações incrementais competem com as inovações radicais. Em contraposição foi criado o conceito de ambidestria segundo o qual as organizações inovadoras produzem tanto inovações radicais quanto incrementais. A presente pesquisa a foi baseada em estudo de caso único de uma empresa de um setor maduro (metalurgia) que pratica Inovação Horizontal (a partir de todas as pessoas). Foram entrevistados dezoito gestores, todos os quatro diretores executivos, dez gerentes, dois coordenadores gerais e dois pesquisadores aposentados. O resultado indicou que a organização é inovadora sistemática, tendo criado um modelo de gestão da inovação ambidestro que produz sistematicamente inovações incrementais e radicais, tanto de produtos como de processo e gestão.
This research deals with the effects caused by the search for innovation from all the people of the organization, particularly the possibility of the organization becoming innovative, understood as capable of systematically producing innovations of any nature and magnitude. This issue is relevant because innovation from all the people of an organization, practically has not been studied by the experts in innovation. Although much approached by the movement of quality in the theme of continuous improvement via kaizen type suggestion systems. The denomination Horizontal Innovation was created by the author to designate the innovations that originate from all the employees of the organization, usually from internal programs of suggestions. Internal feedback systems basically produce incremental innovations, called by quality experts as continuous improvements. Some authors have in the past presented the theory that incremental innovations compete with radical innovations. In contrast, the concept of ambidexterity was created whereby innovative organizations produce both radical and incremental innovations. The present research was based on a single case study of a company from a mature sector (metallurgy) that practices Horizontal Innovation (from all people). Eighteen managers, all four executive directors, ten managers, two general coordinators and two retired researchers were interviewed. The result indicated that the organization is a systematic innovation, having created an ambidextrous innovation management model that systematically produces incremental and radicals innovations, of product, process and management.
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Ferreira, Adriana de Souza Sergio. "Implante permanente de sementes de iodo e prostectomia radical em portadores de câncer de próstata: análise comparativa de uma coorte de base hospitalar." Universidade Federal de Juiz de Fora (UFJF), 2010. https://repositorio.ufjf.br/jspui/handle/ufjf/2610.
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Este estudo teve como objetivo analisar e comparar a sobrevida livre de recidiva bioquímica em cinco anos e fatores prognósticos em pacientes portadores de câncer de próstata submetidos à braquiterapia ou cirurgia radical. Foram analisados 129 pacientes com câncer de próstata, destes 64 foram submetidos à braquiterapia permanente com sementes de Iodo 125 e 75 pacientes foram tratados com prostatovesiculectomia radical, no período de janeiro de 2002 a dezembro de 2005, em um hospital da rede privada da cidade de Juiz de Fora-MG. As principais variáveis analisadas, coletadas dos prontuários dos pacientes, foram: idade, data de nascimento, PSA inicial, escore de Gleason à biópsia prostática e na peça cirúrgica para os pacientes operados, estadiamento clínico e patológico para os casos cirurgicos, volume da próstata ao pré-planejamento e no momento da braquiterapia, atividade das sementes de Iodo 125 e dosagens seriadas de PSA após o tratamento. Os pacientes foram classificados, segundo D’Amico, em grupos de risco: baixo, intermediário e alto. A recidiva bioquímica foi definida como níveis de PSA> 0,4ng/ml para os casos de prostatectomia radical e três elevações consecutivas de PSA para os pacientes implantados (ASTRO). Para estudo do efeito do tratamento na sobrevida livre de recidiva bioquímica foram geradas curvas de Kaplan-Meier, e teste de log-rank foi usado para determinar diferenças entre as curvas. A influência de múltiplas variáveis na sobrevida livre de recidiva bioquímica, como Gleason, estadiamento, iPSA, categoria de risco e idade foram estimados por regressão de Cox. No primeiro artigo, foi observada taxa de sobrevida livre de recidiva bioquímica superior (p=0,0056) para os pacientes submetidos à braquiterapia 79,70% (IC95%:66,87-87,99) quando comparado aos pacientes submetidos à cirurgia 44,30% (IC95%:23,28-63,47) sendo identificados como fatores prognósticos associados de forma independente à sobrevida livre de recidiva bioquímica a modalidade terapêutica (HR= 3,33 ;IC95% :1,41-7,88), os níveis séricos de iPSA (HR=2,54;IC95%:1,11-5,78) e a categoria de risco (HR=4,18 ;IC95%:1,89-9,23). No segundo artigo, que avaliou somente os pacientes submetidos à braquiterapia, foi verificada uma taxa de sobrevida livre de recidiva bioquimica em cinco anos, significativamente superior (p=0,0012) para os pacientes do grupo de baixo risco 91,6% (IC 95%:75,92-97,24), quando comparada com àquela dos pacientes do grupo de risco intermediário/alto 59,19% (IC 95%:36,00-76,40). A sobrevida livre de recidiva bioquimica também foi significativamente superior nos pacientes com iPSA ≤ 10ng/ml (p=0,0084) e com escore de Gleason ≤ 6 à biópsia prostática (p=0,0057). Na análise multivariada, o risco de falha bioquímica também se manteve maior nos pacientes que pertenciam ao grupo de risco moderado/alto e para pacientes com iPSA superior a 10ng/ml. Os dados de sobrevida livre de recidiva bioquimica em cinco anos, para os pacientes desta análise, tratados com braquiterapia, foram comparáveis aos da literatura.
This study aimed to analyze and compare the biochemical relapse-free survival at five years and prognostic factors in patients with prostate cancer undergoing radical surgery or brachytherapy. We analyzed 129 patients with prostate cancer, these 64 underwent brachtherapy with permanent seeds implantation and 75 patients were treated with radical prostatectomy, from January 2002 to December 2005 in a private hospital network in the city of Juiz de Fora-MG. The main variables analyzed were collected from medical records and were: age, date of birth, initial PSA, Gleason score of prostate biopsy and of surgical specimens, clinical and pathologic staging on surgical cases, the prostate volume pre-planning and at the time of brachytherapy, seed activity of lodine 125 and serial measurements of PSA after treatment. Patients were classified according to D’Amico, at risk groups; low, intermediate and high. The biochemical recurrence was defined as PSA levels>0.4 ng/ml for cases of radical prostatectomy and three consecutive elevations of PSA for patients implanted (ASTRO). For the study of the effect of the treatment on biochemical relapse-free survival Kaplan-Meier curves were generated, and log rank test was used to determine the differences among the curves. The influence of multiple variables in the biochemical relapse-free survival as age, initial PSA, Gleason score, staging and risk category was estimated by Cox regression. In the first article, was observed rate of biochemical relapse-free survival superior (p = 0.0056) for patients undergoing brachytherapy 79.70% (CI95% :66,87-87, 99) when compared with patients undergoing surgery 44.30% (CI95% :23,28-63, 47) and were identified as prognostic factors independently associated with survival free of biochemical recurrence modality therapy (HR = 3.33, CI95% :1,41-7 88), serum levels of IPSA (HR = 2.54, CI95% :1,11-5, 78) and risk category (HR = 4.18, CI95% :1,89-9, 23). In the second article, which evaluated only the patients who underwent brachytherapy, there was a rate of biochemical relapse-free survival at five years, significantly higher (p = 0.0012) for patients with low-risk group 91.6% (CI 95% :75,92-97, 24), when compared with that of patients in the intermediate/high risk group 59.19% (CI95% :36,00-76, 40).The biochemical relapse-free survival was also significantly higher in patients with IPSA ≤ 10ng/ml (p = 0.0084) and Gleason score ≤ 6 on prostate biopsy (p = 0.0057). In multivariate analysis, the risk of biochemical failure also remained higher in patients who belonged to the group of moderate / high risk and patients with IPSA more than 10ng/ml. Data from biochemical relapse-free survival at five years for the patients of this analysis were comparable to literature.
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Ghadban, Ali. "Synthèse et caractérisation de glycopolymères à base d'oligoalginates en milieu aqueux." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00923140.
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La synthèse de glycomonomères à base d'oligoalginate (AlgiMERs) et leur polymérisations conventionnelles et RAFT en solution aqueuse ont été étudiés. Premièrement, l'oligoalginates de départ ont été transformés soit dans le glycosylamines correspondant ou en amino alditols (via une amination réductrice). A cette étape, l'optimisation des protocoles d'amination ont été identifiées par la réalisation d'une étude systématique sur un simple acide uronique (acide D-glucuronique). Deuxièmement, les sucres aminés ont été obtenus a réagi avec une électrophile portant un groupe vinyle polymérisable à céder AlgiMERs. Le glycomonomères résultant n'a pas homopolymérisé même en haute force ionique et pour temps de réaction longs, mais leur copolymérisations radicalaire conventionnelles avec N-(2-hydroxyéthyl)méthacrylamide (HEMAm) donne de glycopolymères avec de haute mass molaires (Mw ≈ 1.500.000 Da) contenant jusqu'à 50% en masse de oligoalginate. Une étude cinétique a confirmé que la consommation des deux monomères suivi une cinétique de premier ordre et que les AlgiMERs ont été intégrées tôt dans le processus de polymérisation. Basé sur ces résultats, l'enquête a été étendue à la copolymérisation radicalaire vivante en milieu aqueuse et glycopolymères gradient bien définies ont été obtenues (Mn = 12 000 Da - 90 000 Da; PDI ≤ 1,20). Enfin, j'ai pu prouver qu'un polymère synthétique portant des résidus d'oligo (1→4)-α-L-guluronan conduit des gels en présence d'ions Ca2+ et offre un hydrogel transparent et stable.
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Boursier, Thomas. "Synthèse et caractérisation de copolymères à base d’acide méthacrylique et de nouveaux macromonomères hydrophiles : rôle de leur solvatation sur la fluidité et la viscosité des compositions cimentaires." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10006.
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Le but de cette thèse est d'évaluer le rôle de la solvatation des PCP (copolymère greffé utilisé en tant qu'additif du béton) sur la fluidité et la viscosité des bétons. Pour répondre à cette problématique, des copolymères greffés différant par la nature chimique des chaînes latérales sont synthétisés. L'état de solvatation des PCP est évalué à l'aide du paramètre de Flory-Huggins χ. Ce dernier est calculé à partir du 2nd coefficient du viriel A2, déterminé par diffusion de la lumière. Des valeurs du paramètre χ de 0,37 ; 0,43 ; 0,47 et 0,48 ont été obtenues pour des PCP comportant des chaînes latérales à base d'éthylène glycol (EG), de 2-méthyloxazoline (MOx), de N-vinylpyrrolidone (NVP) et de N-acryloylmorpholine (NAM), respectivement. Le pouvoir couvrant des PCP et leur épaisseur de couche peuvent être calculés par l'intermédiaire d'une formule proposée par Flatt. L'introduction des PCP à différents dosages (donc différents taux de recouvrement) à des suspensions de calcite a permis de montrer qu'à même taux de recouvrement de surface, tous les PCP induisaient la même fluidité, alors que l'épaisseur de couche de PCP diffère de plus de 50% dans les cas les plus extrêmes. Le taux de recouvrement de surface joue un rôle tout aussi important en ce qui concerne la viscosité des suspensions. Appliquer ces conclusions sur un mortier s'avère délicat car les PCP pourraient entrainer des retards d'hydratation différents en fonction de la nature des chaînes latéralesThe objective of this PhD work is the evaluation of the role of the solvation of PCP (grafted copolymer used in concrete as additive) on the concrete fluidity and viscosity. Grafted copolymers with different side-chains were synthesized. The solvation state of the PCP was estimated by mean of the χ Flory-Huggins parameter. The latter was calculated from the 2nd virial coefficient A2, itself determined by light scattering measurements. χ -parameter values of 0,37 ; 0,43 ; 0,47 and 0,48 are obtained for PCP respectively possessing ethylene glycol (EG), 2-methyloxazoline, N-vinylpyrrolidone and N-acryloylmorpholine-based side-chains. The surface coverage of the PCPs and their layer thickness can be calculated with Flatt’s formula. The introduction of the PCPs at different contents (therefore different surface coverage ratio) to calcite suspensions showed that at same surface coverage ratio, all PCPs induce the same fluidity, although the adsorbed PCP layer thickness differed up to 50% in the certain cases. The surface coverage played also a keyrole in the suspensions viscosity. The transposition of these results to a mortar seemed however risky since PCPs might lead to hydration delays depending on the chemical nature of the side-chains
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Dumas, Ludovic. "Post-modification par irradiation γ de polymères à base de fluorure de vinylidène : Applications aux membranes séparatrices de supercapacité." Phd thesis, INSA de Lyon, 2012. http://tel.archives-ouvertes.fr/tel-00801543.
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Ce travail porte sur la modification de matrices polymères à base de fluorure de vinylidene pour permettre leur utilisation en tant que membrane séparatrice dans les supercapacités. Basé sur un procédé d'irradiation par rayonnement γ, l'objectif principal était la limitation du gonflement du polymère lorsqu'il est mis en contact d'un milieu liquide relatif à l'application tout en gardant d'excellentes affinités avec celui-ci. Le processus de base exploité étant la formation et la réaction des radicaux lors de l'irradiation du polymère, une partie de la thèse a été consacrée à leur étude par résonance paramagnétique électronique (RPE). Un modèle de simulation de spectre RPE a été mis en place pour identifier et quantifier chacune des espèces radicalaires. L'effet de la dose d'irradiation, de la durée d'un recuit et de la nature de la matrice polymère (homo, copolymère) sur la proportion de ces espèces et sur leur réactivité a été évalué. Un lien avec la formation d'un réseau a été proposé. Une attention particulière a ensuite été apportée à l'augmentation de la densité de réticulation avec le concours d'un agent réticulant, le TAIC. Pour terminer, une stratégie de modification des propriétés de surface du PVDF a été élaborée. Elle consiste dans un premier temps à radiogreffer un polymère à la surface du PVDF puis à modifier, dans un second temps, les greffons par une chimie douce et sélective. En conclusion, les approches complémentaires développées au cours de cette thèse ont permis de comprendre la radiolyse des polymères et de mettre à profit les processus élémentaires pour développer des stratégies robustes et prometteuses de modulation des propriétés.
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Nzulu, Frida. "Développement de procédés de polymérisation catalysés par des complexes d'or." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066445.
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Ces travaux de thèse ont pour but de développer des procédés de polymérisation efficaces catalysés par des complexes organométalliques à base d'or. Dans une première partie, nous avons développé un nouveau procédé de polymérisation par polyaddition faisant intervenir des carbènes d'or formés par réaction de cycloisomérisation d'esters propargyliques catalysée par un complexe d'or carbophile. Des structures polymères originales et inédites composées d'un motif de répétition phényle vinylcyclopropane ont été proposées. Cette méthodologie a été appliquée à une variété d'esters propargyliques, tout en portant une attention particulière à l'augmentation de la solubilité et du degré de polymérisation des polymères. Une post-fonctionnalisation par l'hydrolyse de l'ester palmitate a été décrite et a permis d'accéder à une nouvelle architecture de polycétones. Des travaux préliminaires de conduction électrique ont montré que ces polycyclopropanes conjugués se comportaient comme des semi-conducteurs. Dans une seconde partie, une combinaison de deux processus de polymérisation associant, une polymérisation cationique vivante et une polymérisation radicalaire photo-induite pour la préparation de copolymères à blocs a été étudiée. Le complexe dinucléaire d'or(I) [Au2( μdppm)2]Cl2 a prouvé toute son efficacité pour catalyser la polymérisation par photo-ATRP d'acrylates en solution et en laminé, contrôlée par la lumière visible ou UVA. Finalement, des résultats préliminaires ont montré qu'il est possible de combiner une polymérisation cationique par RAFT catalysée par un acide de Lewis avec une polymérisation radicalaire photo-induite par RAFT sans utilisation de catalyseur photorédoxThe aim of this PhD work was to develop highly effective polymerization processes using gold complexes and the synthesis of original polymers. On the first research topic we have developed the first polymerization process through a gold carbenoic intermediate, leading to an original polymer composed by a phenyl vinylcyclopropyl monomer unit. This methodology was utilized to the polymerization of a variety of propargylic esters. Special attention has been paid to increase the solubility and the polymerization degree of the polymers. Post-functionnalization by hydrolysing the ester group leads to a new polyketone architecture. Preliminary electric studies showed that this conjugated polycyclopropane acts as a semi-conductor. The aim of the second research topic was to control efficiently the formation of block copolymers by combining living cationic and photo-induced radical polymerizations catalyzed in a one-pot procedure. A dinuclear gold(I) complex based photocatalyst [Au2(μ-dppm)2]Cl2 catalyzed efficiently polymerization of acrylates in solution and in laminate through an atom transfer radical polymerization process controlled by light exposure (visible or UV-A light). Finally, preliminary results showed it is possible to combine cationic reversible addition-fragmentation chain transfer polymerization catalyzed by a Lewis acid with radical reversible addition-fragmentation chain transfer polymerization without photoredox catalyst or radical initiator but only with an external stimuli, the light
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Zarrouki, Arthur. "Synthèse de polymères à base d'éthylène pour additiver les carburants." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1039.
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Les gazoles, carburant automobile préféré des français, sont « additivés » afin de permettre leur utilisation en hiver. Les n-paraffines présentes dans ces gazoles cristallisent en effet à basse température. Ces cristaux peuvent alors entraîner le colmatage des filtres protecteurs situés en amont du moteur. Des polymères à base d'éthylène, notamment les copolymères éthylène-acétate de vinyle (EVA), sont utilisés pour abaisser la température à laquelle les problématiques de filtration adviennent. Un nouveau procédé de copolymérisation radicalaire d'éthylène et d'acétate de vinyle, à plus basse pression et à plus basse température, que le procédé industriel actuel, a été développé au cours de cette thèse. Une grande variété d'EVA a ainsi été obtenue. Ils présentent des caractéristiques structurelles et une efficacité, pour le traitement des gazoles, similaires aux EVA commerciaux. Ce procédé a, par ailleurs, permis la synthèse d'autres co- et terpolymères de l'éthylène variant par la nature des comonomères polaires utilisés ou par l'architecture. Des modèles de copolymères EVA ont été également synthétisés par métathèse. La grande diversité d'additifs polymères à disposition combinée à des techniques d'analyse thermique et de diffusion des rayons X mises en oeuvre au plus proche de l'application (en particulier dans le gazole), ont permis de mieux appréhender leur mode d'action sur la cristallisation des n-paraffines. Les spécificités structurelles, des polymères, conditionnant leur efficacité pour le traitement de la tenue à froid des gazoles ont également pu être établiesThe additivation of diesel fuels allows operating engines at low temperatures without filter blocking and thus fulfilling legal requirements. Ethylene based copolymers such as ethylene-vinyl acetate copolymers, made by free radical polymerization at high pressure (above 2000 bars) and high temperature (above 200 °C) are frequently used as middle distillate cold flow improvers (MDFI). A new free radical copolymerization process of ethylene and vinyl acetate in organic solvent media has been developed. This process gives access to polymers close to commercial MDFI additives under tremendous less drastic conditions (under 250 bars of ethylene and 70 °C). Thanks to this process, a wide diversity (variation of the nature of the polar unit, of polymer architecture…) of ethylene based polymers was obtained. Moreover, EVA model copolymers have been synthesized by metathesis. Thanks to these numerous and diverse ethylene based polymers combined with thermal analysis and X-ray scattering studies a better understanding of the operating mode of these additives in a diesel fuel has been achieved. The structural characteristics of the polymers enabling their effectiveness as diesel fuel cold flow improvers have also been established
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Loste, Julien. "Elaboration de matériaux composites transparents à base de nanoparticules hybrides cœur@écorce." Thesis, Pau, 2014. http://www.theses.fr/2014PAUU3054/document.
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L’incorporation de particules inorganiques dans une matrice polymère confère de nouvelles propriétés au matériau ou améliore de manière significative les propriétés déjà existantes. Cependant, l’apparence visuelle perçue, telle que la transparence, peut être altérée par des phénomènes de diffusion de la lumière par les particules. Cette diffusion de la lumière est principalement conditionnée par la dimension des particules –ou agrégats de particules- et la différence d’indice de réfraction entre la matrice et les charges. Afin de traiter ces deux problèmes, l’objectif de nos travaux était de contrôler simultanément l’état de dispersion des nanoparticules inorganiques dans la matrice polymère et l’indice de réfraction des nanoparticules de façon à l’ajuster à celui de la matrice. Pour élaborer ce nouveau composite, nous avons synthétisé des nanoparticules hybrides cœur@écorce avec un cœur inorganique qui apporte les nouvelles propriétés et une écorce polymère d’épaisseur contrôlée, obtenue par polymérisation radicalaire contrôlée par voie nitroxyde amorcée à la surface des nanoparticules inorganiques. L’écorce polymère limite l’agrégation des particules et permet de modifier l’indice de réfraction moyen des nanoparticules cœur@écorce. En contrôlant l’épaisseur et la nature chimique de l’écorce polymère, nous cherchons à ajuster l’indice de réfraction des nanoparticules cœur@écorce à celui de la matrice. Les nanoparticules ont ensuite été dispersées dans une matrice de poly(méthacrylate de méthyle). Les propriétés optiques des composites ont été caractérisées par spectrogoniophotométrie, afin d’obtenir des informations sur l’intensité et la distribution angulaire de la lumière transmise par le composite. La transparence des nanocomposites a été fortement améliorée en ajustant l’indice de réfraction des nanoparticules cœur@écorce à celui de la matriceThe incorporation of inorganic particles into a polymer matrix confers new properties to the material or enhances significantly existing properties. However, the perceived visual appearance, such as loss of transparency, might be modified by the scattering of light by the particles. This light scattering is mainly due to the particle –or aggregates of particles- dimensions and the refractive index difference between matrix and fillers. In order to address both issues, the objective of the present work was to control simultaneously the dispersion state of the inorganic nanoparticles into the polymeric matrix and the refractive index of the nanoparticles to match the one of the matrix. To achieve this new composite, we designed hybrid core@shell nanoparticles with an inorganic core that brings new properties and a polymer shell of controlled thickness, obtained by surface-initiated nitroxide mediated controlled radical polymerization. The polymer shell limits the aggregation of the particles and enables us to tune the average refractive index of the hybrid core@shell particle. By controlling the thickness and the chemical nature of the polymeric shell, we targeted to match the refractive index of the hybrid core@shell particle to the one of the polymeric matrix. The nanoparticles were further dispersed into a poly(methyl methacrylate) matrix. Optical properties of composites were characterized by spectrogoniophotometry which gave us informations about the intensity and the angular distribution of the transmitted light by the nanocomposites. The transparency of the nanocomposites was strongly enhanced for core@shell particles fulfilling the refractive index matching conditions
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Borisova, Olga. "Synthèse et contrôle de l'auto-assemblage de nouveaux copolymères à gradient à base de styrène et d'acide acrylique." Thesis, Pau, 2012. http://www.theses.fr/2012PAUU3018/document.
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L'objectif principal de ce travail de thèse est la synthèse et l'étude des propriétés en solution de nouveaux copolymères amphiphiles di- et triblocks à gradient de styrène et d'acide acrylique qui sont capables d'association réversible en milieu aqueux. Nous avons étudié la cinétique et le mécanisme de la polymérisation radicalaire contrôlée par l’intermédiaire d’un nitroxyde (NMP), afin de déterminer les caractéristiques quantitatives des réactions de terminaison réversible lors de ce processus. Puis la NMP a été utilisée pour la synthèse de deux architectures différentes de copolymère à gradient: copolymères di- et triblocs. L'auto-assemblage des copolymères à gradient dans l'eau a été étudiée par DLS, SANS et TEM. Les changements réversibles du nombre d'agrégation au cours des cycles de pH ont été observés. De plus, nous avons étudié l'effet du pH et de la force ionique sur les propriétés rhéologiques en solution de copolymères triblocs à gradient. Nous nous sommes également intéressés à synthétiser des brosses de polymère sur surface d'or et étudié leur propriétés pH et électro-sensibles en milieu aqueuxThe main goal of our work was the synthesis and the study of solution properties of novel amphiphilic di- and triblock-gradient copolymers based on styrene and acrylic acid which are capable of reversible association in aqueous solution. We studied the kinetics and the mechanism of nitroxide-mediated radical polymerization (NMP) in order to determine the quantitative characteristics of the reversible termination reaction in this process. Then NMP was employed to the synthesis of two different block-gradient copolymer architectures: di- and triblock-gradient copolymers. The self-assembly of the block-gradient copolymers in water was studied by DLS, SANS and TEM. The reversible changes of aggregation numbers in cycles of pH were observed. We also investigated the effect of pH and ionic strength on rheological properties of triblock-gradient copolymer solution. Then, we synthesized polymer brushes on the gold-coated surface and studied their pH- and electro-responsive properties in aqueous media
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Önal, Emel. "Molecular magnetic materials based on porphyrin macrocyles." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10103/document.
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La construction de nouvelles architectures d'aimant moléculaire basé sur l'approche métal-radical repose sur la conception de nouvelles molécules radicalaires. Dans cette optique, notre stratégie s'est concentrée sur la synthèse de porphyrins incorporant des composés radicaux libres. En effet, les porphyrines sont des composés π conjugués qui devraient favoriser la délocalisation de spin et la transmission des interactions magnétiques sur l'entier macrocycle et de plus sur l'ensemble du composé obtenu. A cause de leur excellente stabilité dans une grande diversité d'environnements chimiques et leur capacité à coordonner avec des métaux de transitions, notre choix s'est porté sur les radicaux nitroxides. Dans cette thèse, une série de porphyrines contenant des tBUNO, nitronyl and imino nitroxide directement liés sur le squelette de la molécule ont été synthétisées. Les macrocycles obtenus ont été caractérisés par UV-Vis, Masse et RPE spectroscopie. De plus, durant ce travail, des intermédiaires réactionnaires intéressant ont été obtenus et caractérisés pour la première fois. Ce fut le cas pour la meso-tetrakis(4-formylphenyl)porphyrin et ses équivalents métallés pa le Cu(II) et le Mn(II). Ainsi que pour quelques précurseurs prometteurs de macrocycle tetrapyrroliques comme 2-(3,4-dicyanophenyl)-4,4,5,5-tetramethylimidazoline-3-oxide-1oxyl, 2-(3,4-dicyanophenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl and 2-(4-benzaldehyde)-4,4,5,5-tetramethylimidazoline-1-oxyl. D'après ce que nous savons, ces composés représentent le premier exemple de porphyrines substituées par des nitronyl et imino nitroxide radical, ayant été caractérisées sans ambiguïté par des méthodes spectroscopiquesThe preparation of Molecule-Based Magnets is based on the assembling carriers of magnetic moment. These may be the metal ions only with diamagnetic linkers or the metal ions connected through open-shell organic molecule. The building of novel Molecule-Based Magnets architectures following the metal-radical approach relies on the design of innovative open-shell organic molecular blocks. In this regard, we focus our strategy on the synthesis of porphyrins incorporating free radicals. Indeed, porphyrins compounds are π-conjugated systems which should favor spin delocalization and the transmission of the magnetic interactions on the overall macrocycle and further over the all architecture. Due to their excellent stability in a wide variety of chemical environments, and their abilities to coordinate with transition metal we focus our attention on nitroxide radicals. In this dissertation a series of porpyrin macrocycles were synthesized, bearing tBuNO, nitronyl and imino nitroxide covalently linked to the skeleton. Characterization was done by UV-Vis, Mass and EPR spectroscopy. Moreover during this work some interesting synthetic intermediates were obtained with good yield and characterize for the first time. This was the case for meso-tetrakis(4-formylphenyl)porphyrin and its corresponding metallated derivatives by Cu(II) and Mn(II). Some novel promising tetrapyrrolic macrocycle precursors bearing nitronyl and imino nitroxides free radicals as 2-(3,4- dicyanophenyl)-4,4,5,5-tetramethylimidazoline-3-oxide-1-oxyl, 2-(3,4- dicyanophenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl and 2-(4-benzaldehyde)-4, 4, 5, 5-tetramethylimidazoline-1-oxyl. To the best of our knowledge, these compounds represent the first example of nitronyl and imino nitroxide substituted porphyrin derivatives that have been unambiguously characterized by spectroscopic techniques
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Akin, Myles. "Site specific thermodynamic study of OH radical addition to DNA bases." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33919.
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In medical and health physics, we are interested in the effects of ionizing radiation on biological systems, in particular, human biology. The main process by which ionizing radiations causes damage to biological systems, is through the creation of radicals close to DNA strands. The radicals are very reactive and those created within close proximity to DNA will react with the DNA causing damage, in particular single strand or double strand breaks. This damage to the DNA can cause mutations that can kill the cell, either mitotically or apoptotically, or possibly lead to a cancerous formation. Therefore it is important to study how these radicals interact with DNA strands for a correlation between the resultant products of radical reactions and DNA strand breaks. For this study, we look at the most important radical, the OH radical and it's addition to DNA bases. We will study, through quantum chemistry, the thermodynamics of OH radical addition to the four bases, Adenine, Guanine, Cytosine and Thymine. The Jaguar program developed by Schrodinger was used for DFT calculations of the Gibbs free energy of the addition. In addition, calculations for the partial charge, HOMO's and Fukui indices were calculated and compared to experiment.
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Fabrello, Chantal. "Etude et realisation d'une preforme de fibre optique en polymere a base de methacrylate de methyle." Toulouse 3, 1986. http://www.theses.fr/1986TOU30127.
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Khchoum, Salem. "Les affixes/créments dans le lexique de l'arabe : exploration du niveau submorphémique de l'arabe." Thesis, Lyon, École normale supérieure, 2014. http://www.theses.fr/2014ENSL0963.
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Cette thèse s’inscrit dans le cadre des travaux de révision de la structure de la racine sémitique en général, et arabe en particulier. Dans l’introduction, nous avons entamé une relecture critique des efforts des grammairiens arabes en quête du seuil minimal du sens, et qui ont abouti à poser la racine trilitère comme étant ce seuil ultime et inanalysable. Ce choix a été fait malgré tous les signes d’instabilité que comporte ce concept - tels que son incapacité à expliquer la réversibilité de l’ordre des consonnes et leur variation phonétique indépendamment du sens. C’est un choix synchronique anhistorique qui exclut la notion de temps, et émane d’une conception révélationniste (tawqîf) du langage. Au XIXe siècle, l'évolutionnisme darwiniste, étendu à la philologie, met à mal cette conception figée de la racine. En intégrant la notion de temps, nombre d’Orientalistes, suivis par quelques philologues arabes de l’époque, ont montré à travers une approche comparative que la racine trilitère est une forme évoluée d’une base primitive bilitère (ou monosyllabique). Depuis, plusieurs explications ont été proposées pour la formation de la racine trilitère à partir d’une base bilitère (croisement, incrémentation, affixation). Certains linguistes comme Hurwitz ont essayé d’identifier et de systématiser par déduction les éléments ternaires et leurs valeurs sémantiques. Dans notre travail, qui s'inscrit dans le cadre de la théorie des matrices et des étymons, nous démontrons à travers l’analyse synchronique de près de 1000 items que la racine trilitère est analysable en termes d’étymons bilitères et de créments, ou affixes. Les éléments affixables ou incrémentables à la base sont phonétiquement les mêmes (gutturales, sonantes, labiales, nasales) et corrélés souvent aux mêmes valeurs grammaticales (factitif, statif, moyen) ou sémantiques (l’intensif). La troisième position de la racine est la position privilégiée dans ce processus d’affixation/incrémentation. La racine trilitère n’est donc pas le seuil minimal du sens, et s’avère réductible à une base biconsonantique rendue trilitère grâce à un segment crément ou affixe. Ceci peut avoir un effet sur notre conception du lexique arabe, désormais réorganisable autour des bases bilitères soit abstraites (les traits phonétiques), soit concrètes (les étymons primitifs), qui sont à leur tour transformables en radicaux trilitères grâce à une liste préalable de créments et affixes spécifiant la signification primordiale véhiculée par la base bilitèreThis thesis is part of the revisionist work on the structure of the Semitic root in general, and the Arabic root in particular. In the introduction, we present a critical review of the efforts of Arab grammarians in their quest of a minimum linguistic threshold associated with meaning, a quest that resulted in establishing the triliteral root as the ultimate unanalysable unit. This choice was made despite the many obvious shortcomings of this theoretical framework, such as its inability to explain the reversal of the order of consonants, or their phonetic variation (regardless of its meaning). It is an anhistorical, synchronic choice that excludes the notion of time, and finds its roots in a revelationnist (tawqîf) linguistic framework. In the end of the nineteenth century, the extended Darwinist theory has undermined this static conception of the root. By integrating the notion of time, a number of Orientalists - followed by some Arab philologists of that period - showed, through a comparative methodology, that the triliteral root has evolved from a primitive monosyllabic (or biconsonantal) root. Since then, several explanations have been proposed for the formation of the triliteral root from a biliteral base (crossed bilateral roots, affixation of formative increments or determinatives).Some linguists, such as Hurwitz, tried to identify and to systematize by deduction the ternary elements and their semantic values. In this work, which is carried within the framework of the Matrix and Etymons Theory , we demonstrate through the synchronic analysis of nearly 1,000 trilateral items that the triliteral root is analyzable in terms of biliteral etymons and of separable increments or affixes added at the beginning (prefixation), the middle (infixation) or the end (suffixation) of bilateral bases.The characteristic elements that can be affixed or incremented on the base are phonetically similar (gutturals, sonorants, labial, and some dentals) and correlated often with the same grammatical (factitive, stative, reflexive or middle voice) or semantic (intensive) values. The third position of the root is the position favored in this process of affixation / incrementation. Thus, the triliteral root is not the minimal threshold of meaning, and can be broken down to a biconsonantal base, which became triliteral thanks to an incremental or affixal segment. These findings may affect our perception of the Arabic lexicon, which can now be rearranged around biliterals bases, either abstract ( i.e. phonetic features), or concrete (i.e. historical primitive etymons) that are in turn convertible into triliteral radicals through a preliminary list increments and affixes that specify the primary meaning conveyed by the bilateral base
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Robbes, Anne-sophie. "Nanocomposites à base de particules magnétiques : synthèse et contribution de la dispersion des charges et de la conformation des chaines sur les propriétés de renforcement." Thesis, Paris 11, 2011. http://www.theses.fr/2011PA112201/document.
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Les propriétés mécaniques de films polymériques peuvent être considérablement améliorées par l'inclusion de nanoparticules au sein de la matrice du fait de deux effets majeurs : (i) la structure locale de la dispersion des charges et (ii) la modification potentielle de la dynamique et de la conformation des chaînes à l'interface charge/polymère. Néanmoins, les mécanismes précis qui permettent de relier ces contributions à l’échelle nanométrique aux propriétés macroscopiques des matériaux, et en particulier aux propriétés mécaniques, sont actuellement mal décrits. Dans ce contexte, nous avons synthétisé des nanocomposites modèles à base de nanoparticules magnétiques de maghémite γ-Fe2O3 (nues ou greffées d'une couronne de polystyrène (PS) par polymérisation radicalaire contrôlée) dispersées dans une matrice de PS, que nous avons caractérisé en couplant la diffusion de rayonnement (Rayons X et neutrons) et la microscopie électronique à transmission. En jouant sur différents paramètres tels que la taille des particules, la concentration, ou le rapport de taille entre les chaînes greffées et celles de la matrice pour les charges greffées, nous avons obtenu des nanocomposites présentant un éventail de dispersions de charges variées, contrôlées, parfaitement reproductibles, allant de particules individuelles ou d’agrégats ramifiés jusqu’à la formation d’un réseau de charges connecté. En appliquant un champ magnétique externe durant la synthèse des nanocomposites, nous sommes parvenus à aligner les différentes structures le long de la direction du champ et ainsi former des matériaux présentant des propriétés remarquables de renforcement anisotropes. La conformation des chaînes au sein des nanocomposites, déterminée expérimentalement grâce aux propriétés spécifiques de contraste neutronique du système, n'est pas affectée par la présence des charges, quels que soient le degré de confinement des chaînes, l’orientation, la dispersion ou l'état de surface des charges. L’alignement des charges sous champ magnétique a permis de décrire précisément l’évolution du module de renforcement des matériaux avec la réorganisation structurale locale des charges et des chaînes sous étirement, et de finalement mettre en évidence le rôle majeur joué par la réorganisation des charges sous déformation dans les mécanismes de renforcementThe mechanical properties of polymeric nanocomposite films can be considerably enhanced by the inclusion of inorganic nanoparticles due to two main effects: (i) the local structure of fillers dispersion and (ii) the potential modification of the chains conformation and dynamics in the vicinity of the filler/polymer interface. However, the precise mechanisms which permit to correlate these contributions at nanometric scale to the macroscopic mechanical properties of the materials are actually poorly described. In such a context, we have synthesized model nanocomposites based on magnetic nanoparticles of maghemite γ-Fe2O3 (naked or grafted with a polystyrene (PS) corona by radical controlled polymerization) dispersed in a PS matrix, that we have characterized by combining small angle scattering (X-Ray and neutron) and transmission electronic microscopy. By playing on different parameters such as the particle size, the concentration, or the size ratio between the grafted chains and the ones of the matrix in the case of the grafted fillers, we have obtained nanocomposite films a large panel of controlled and reproducible controlled filler structures, going from individual nanoparticles or fractal aggregates up to the formation of a connected network of fillers. By applying an external magnetic field during the film processing, we succeeded in aligning the different structures along the direction of the field and we obtained materials with remarkable anisotropic reinforcement properties. The conformation of the chains of the matrix, experimentally determined thanks to the specific properties of neutron contrast of the system, is not affected by the presence of the fillers, whatever their confinement, the dispersion the fillers or their chemical state surface. The alignment of the fillers along the magnetic field has allowed us to describe precisely the evolution of the reinforcement modulus of the materials with the structural reorganization of the fillers and the chains at the local scale under stretching, and thus to highlight the key role played by the fillers reorganization under stretching on the nanocomposite reinforcement mechanisms
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Wickenden, Jason. "Development of heteroatom radical based synthetic strategies." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/45730.
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This thesis presents investigations of carbo- and heterocycle formation using radical relay cyclization reactions initiated by alkoxy radicals, cyclic imine formation using substoichiometric stannane and photodeoxygenation reactions involving benzotriazole-borane complexes. Chapter 1 describes our investigations and development of radical relay cyclization
reactions initiated by alkoxy radicals that provided carbo- and heterocyclic compounds.
Pairing N-alkoxyphthalimides as alkoxy radical precursors with the slow addition of radical
initiator provided a wide range of carbocycles. Incorporation of functionality into the
linear backbone provided substituted heterocyclic compounds in excellent yield.
Chapter 2 describes the cyclization of aminyl radicals onto silyl enol ethers. The rate
acceleration imparted by the silyl enol ether allowed for high yielding pyrrolidine
formation. Investigations focused on an unexpected cyclic imine product that was
observed in our previous studies. We sought to both optimize our conditions to provide
this imine in the highest possible yield, and investigated the mechanism by which this
imine product may be formed. Chapter 3 describes the development of a photodeoxygenation reaction using
benzotriazole-borane complexes. The coordination of a benzotriazole ligand with
commercially available borane-tetrahydrofuran provides the benzotriazole-borane
complex as a bench stable white powder. DFT calculations suggested these benzotriazoleborane
complexes could behave a radical chain deoxygenation reaction. Irradiation of a
variety of xanthates provided the deoxygenated products in excellent yield. Furthermore,
our work suggests that the benzotriazole ligand may be catalytic in these deoxygenation
reactions.
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Bertho, Sylvain. "Fonctionnalisation d’énamides par voie radicalaire : Catalyse au fer ou application de la chimie des xanthates." Thesis, Orléans, 2018. http://www.theses.fr/2018ORLE2060.
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L’objectif du projet de thèse est d’étudier l’addition d’espèces radicalaires sur des motifs de type énamide non aromatique pour accéder à une diversité moléculaire de dérivés azotés cycliques et acycliques en un minimum d’étapes via des réactions régio- et diastéréosélectives utilisant des conditions éco-compatibles.Dans un premier temps, des énamides non aromatiques originaux possédant divers groupements fonctionnels ont été préparés. L’oxyazidation originale régio- et diastéréosélective d’énamides a ensuite été développée en utilisant une catalyse au fer (II) en présence de dérivés azidobenziodoxolones (ABX) originaux. Cette méthode permet notamment l’accès à des pipéridines α-azido -esters de configuration trans que nous avons valorisé pour accéder à des polycycles azotés originaux.Par la suite, une approche synthétique impliquant une catalyse au fer (II) ou du fer métallique pour fonctionnaliser la position C3 d’énamides a été développée à partir de plusieurs α-halogénocarbonyles selon un processus radicalaire. Enfin, la chimie radicalaire des xanthates a été avantageusement appliquée pour réaliser l’alkylation de cette position. Des conditions permettant d’effectuer une difonctionnalisation ont également été mises en oeuvreThe aim of the thesis is to study the addition of radical species on non-aromatic enamide scaffolds in order to access high molecular diversity of cyclic and acyclic nitrogen-containing compounds in a restricted number of steps via sustainable eco-friendly regio- and diastereoselective reactions.Firstly, non-aromatic enamides bearing different functional groups have been synthesized. Then a regio- and diastereoselective iron-catalyzed oxyazidation of enamides was developed in the presence of novel azidobenziodoxolones (ABX) derivatives under mild reaction conditions. In addition, the versatility of the trans α-azido β-esters piperidines was highlighted by the synthesis of various original nitrogen-containing polycycles.Subsequently, C3 alkylation of enamides with α-halogenocarbonyles. was carried out through an iron (II)-catalysis or a metallic iron-mediated process.Finally, radical xanthate chemistry was applied to achieve the metal-free alkylation of the C3 position of enamides or the difunctionalization of enamides in the presence of a nucleophile
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Weaving, R. "Studies on iron based oxidation." Thesis, University of Sussex, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299031.
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Ajavakom, Anawat. "Novel radical based routes to pyrrolidine trans lactams." Thesis, University of Southampton, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288468.
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Alves, Lemes Maykon. "Magnetic Exchange Coupling in 3d and 4f Complexes Using Radical Tetrazine-based Frameworks." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/39598.
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High symmetry and low coordinated single-ion lanthanides have been a successful recipe to design high performance single molecule magnets (SMMs). However, enhancement of the magnetic properties of polymetallic SMMs is an important challenge. Therefore, this thesis describes the use of redox non-innocent tetrazine-based ligands and d- and f- elements in order to fine-tune the electronic structure of the resulting compounds to promote strong exchange interactions between the spin carriers. As reported in the literature, radical-bridged ligands represent a potential strategy to improve the magnetic properties of polymetallic SMMs. Thus, chapter one introduces principal concepts that govern the physical properties of metal complexes containing radical-bridged ligands.
Chapter two describes the magnetic properties of a unique air-stable tetratopic radical- bridged bpymtz•− (3,6-bis(2-pyrimidyl)-1,2,4,5-tetrazine) templating four Ni(II) metal ions. The dc magnetic studies along with DFT calculations reveal strong ferromagnetic exchange coupling between the Ni− bpymtz•− of J = 98 cm-1 with a spin ground state of S = 9/2.
Chapter three describes the application of another tetrazine-based ligand, bpytz (3,6- bis(3,5-dimethylpyrazolyl)-1,2,4,5-tetrazine) to probe magnetic exchange interactions in a {CoII4} supramolecular square. The modelling of dc susceptibility data shows significant Co(II) - bpytz•− magnetic coupling of J = - 118 cm-1 for a spin ground state ST = 4. While the non-reduced analog displays weak Co(II)-Co(II) exchange of J = - 0.64 cm-1 (S = 0 ground state). Additionally, the radical-radical magnetic exchange contribution was probed with an analogous {ZnII4} square, where a J = -15.9 cm-1 was found.
Chapter four extends the application of reduced tetrazine ligands to lanthanide systems. Here we demonstrate that the systematic reduction of the ligand with cobaltacene (CoCp2) led to the formation of a strongly coupled bpytz•−−bpytz•− bridging ligand. Magnetic measurements combined with ab initio calculations confirm unprecedented intramolecular pi-dimerization preventing strong magnetic Dy(III)−bpytz•− communication.
Chapter five describes the synthesis and characterization of {LnIII4} (Ln = Dy, Gd and Lu) where the Ln(III) ions are bridged by peripheral bpytz•−. The oxophilicity and high coordination numbers preferred by lanthanides ions lead to the formation of a cubane core made up of metal ions bridged by hydroxy ligands (M3-OH−). Experimental and computational studies were applied to verify the nature and strength of the magnetic interactions between the spin carriers.
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Brazi, Eric. "Activation de la liaison C-H : hydroxylation catalytique des hydrocarbures par de nouveaux complexes alkylperoxydiques de cobalt (iii), déshydrogénation sélective et catalytique de cycloalcanes en présence d'éponges à hydrogènes à base d'uranium métal." Paris 6, 1987. http://www.theses.fr/1987PA066680.
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Smith, Gregory Brian. "Investigations into the effects of chain-length-dependent termination and propagation on the kinetics of radical polymerisation." Thesis, University of Canterbury. Chemistry, 2008. http://hdl.handle.net/10092/1455.
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Radical polymerisation (RP) has for many years been an industrially important process, and the kinetics of the process remains an active area of research. As polymerisation proceeds, converting monomer (small molecules) into polymer (long chain molecules), chemical species of a variety of chain lengths are produced. Recent work has pointed toward the fact that rate coefficients for polymerisation reactions (specifically, termination and propagation) are often dependent on the chain-length of the reacting species. The focus of this thesis is to study the effects of chain-length-dependent reactions on the kinetics of RP, by using computer-based modeling and comparing the results of such modeling with experimental data. This enables the understanding of otherwise inexplicable trends and the building of more mechanistically detailed and accurate models for RP kinetics. In Chapter 2, a new model for termination is developed, connecting observations and analyses of termination kinetics at short chain lengths (particularly small molecule studies) with other observations and analyses at long chain lengths (conventional RP kinetics studies) in order to construct a model for termination that is shown to be capable of coherently describing termination kinetics at any chain length. In Chapter 3, this new model for termination is tested at short chain lengths on polymerisations with large quantities of added chain transfer agent. With the inclusion of chain-length-dependent propagation in the model, the model for termination is validated. Chapter 4 is aimed at extending an existing reduced-variable, compact, 'universal' description of steady-state RP kinetics by incorporating all known chain-length dependent reactivities. This both increases computational efficiency over other approaches and provides easily evaluated, approximate analytical expressions for RP kinetics. This foundational theory is applied in Chapter 5 to reach a deeper understanding of the behaviour of the model, and show how experimental data may readily be analysed to extract information about chain-length-dependent termination kinetics. In Chapter 6, the effect of chain-length dependent reactivities on the important technique of single-pulse pulsed-laser polymerisation is investigated, and this technique is validated as the best experimental method for investigation of termination kinetics. In general, a central result of this thesis is that chain-length-dependent reactivities, when acknowledged and properly incorporated into models, can explain many phenomena in RP kinetics which otherwise seem difficult to account for. No exceptions to this principle have been found.
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Malet, Federic Louis Gino. "Aqueous ATRP of amine-based methacrylates." Thesis, University of Sussex, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367786.
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Sadofiev, Sergey. "Radical-source molecular beam epitaxy of ZnO-based heterostructures." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2009. http://dx.doi.org/10.18452/16054.
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Im Rahmen der Dissertation wurden molekularstrahlepitaktische Verfahren zur Züchtung von Hetero-und Quantenstrukturen auf der Basis der Gruppe II-Oxide entwickelt. Insbesondere wurde ein Wachstumsregime weit entfernt vom thermischen Gleichgewicht etabliert, welches die Mischung von CdO und MgO mit ZnO in phasenreiner Wurtzitstruktur ermöglicht, wobei die Gleichgewichtslöslichkeitsgrenzen dramatisch überschritten werden. In den Mischkristallen kann die Bandlücke kontinuierlich von 2.2 bis 4.4 eV eingestellt werden. Das Wachstum verläuft in einem zweidimensionalen Modus und resultiert in atomar glatten Ober- und Grenzflächen. Ausgeprägte RHEED- Intensitätsoszillationen erlauben die atomlagengenaue Kontrolle der Schichtdicken und somit die Realisierung wohl-defi- nierter Einzel- und Mehrfachquantengrabenstrukturen. Diese zeichnen sich durch eine hohe Photolumineszenzquantenausbeute im gesamten sichtbaren Spektralbereich aus. Laseraktivität kann vom UV bis zum grünen Wellenlängenbereich bei Zimmertemperatur erzielt werden. Das Potenzial dieser Quantenstrukturen in Hinblick auf ihre Anwendung in opto-elektronischen Bauelementen wird diskutiert.This work focuses on the development of the novel growth approaches for the fabrication of Group II-oxide materials in the form of epitaxial films and heterostructures. It is shown that molecular-beam epitaxial growth far from thermal equilibrium allows one to overcome the standard solubility limit and to alloy ZnO with MgO or CdO in strict wurtzite phase up to mole fractions of several 10 %. In this way, a band-gap range from 2.2 to 4.4 eV can be covered. A clear layerby- layer growth mode controlled by oscillations in reflection high-energy electron diffraction makes it possible to fabricate atomically smooth heterointerfaces and well-defined quantum well structures exhibiting prominent band-gap related light emission in the whole composition range. On appropriately designed structures, laser action from the ultraviolet down to green wavelengths and up to room temperature is achieved. The properties and potential of the "state-of-the-art" materials are discussed in relation to the advantages for their applications in various optoelectronic devices.
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Cheng, Qigan. "Co(II)-Based Metalloradical Catalysis for Asymmetric Radical Cyclopropanation." Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6206.
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Metal-catalyzed cyclopropanation of olefins with diazo reagents is one of the most general and efficient method to prepare cyclopropanes. The resulting cyclopropyl units are found as a basic structural element in a wide range of naturally occurring compounds and biologically active compounds, and can serve as versatile synthetic intermediates in the synthesis of multifunctionalized cycloalkanes and acyclic compounds. Since Co(II) complexes of D2-symmetric chiral amidoporphyrins [Co(D2-Por*)] were first introduced in 2004, Co(II)-metalloradical catalysis (MRC) have emerged as a new platform for asymmetric cyclopropanation. These metalloradical catalysts have been shown to be highly effective for asymmetric intermolecular cyclopropanation of a broad scope of substrates with different diazo reagents, with excellent diastereoselectivity and enantioselectivity.
This dissertation aims to develop new Co(II)-MRC based enantioselective cyclopropanation systems. It will elaborate on three types of stereoselective cyclopropanation reactions from olefins: radical cyclopropanation with α-halodiazoacetates, asymmetric bicyclization of diazoketones, and radical cyclopropanation with fluoroaryl diazomethanes. These three processes will be examined in the context of diastereo- and enantiocontrol. And also, the application of cyclopropanation products have been demonstrated, which could potentially lead to more exciting works.
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Baltazar, Junior Rene Carlos Cardoso. "Lema de Seidenberg para computar geradores de um radical." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2011. http://hdl.handle.net/10183/29248.
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O objetivo deste trabalho e computar, em alguns casos espec cos, os geradores do radical de um ideal no anel de polinômios K[x1, ..., xn]. Para isso, utilizamos a teoria das bases de Groebner. Primeiramente, usamos o Lema de Seidenberg para computar os geradores do radical de um ideal zero-dimensional onde K e um corpo perfeito e depois utilizamos os resultados de R. Matsumoto para um corpo K de caracter stica positiva e perfeito.The goal of this work is to compute in some speci c cases the generators of the radical ideal in a polynomial ring K[x1, ..., xn]. For this, we use the theory of Groebner bases. First, we use Lemma Seidenberg to compute the generators of the radical of an zero-dimensional ideal, where K is a perfect eld and then we used the results of R. Matsumoto for a eld K of positive characteristic and perfect.
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Fu, Rong. "Biochemical and Spectroscopic Characterization of Tryptophan Oxygenation: Tryptophan 2, 3-Dioxygenase and Maug." Digital Archive @ GSU, 2009. http://digitalarchive.gsu.edu/chemistry_diss/44.
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TDO utilizes b-type heme as a cofactor to activate dioxygen and insert two oxygen atoms into free L-tryptophan. We revealed two unidentified enzymatic activities of ferric TDO from Ralstonia metallidurans, which are peroxide driven oxygenation and catalase-like activity. The stoichiometric titration suggests that two moles of H2O2 were required for the production of one mole of N-formylkynurenine. We have also observed monooxygenated-L-tryptophan. Three enzyme-based intermediates were sequentially detected in the peroxide oxidation of ferric TDO in the absence of L-Trp including compound I-type and compound ES-type Fe-oxo species. The Fe(IV) intermediates had an unusually large quadrupole splitting parameter of 1.76(2) mm/s at pH 7.4. Density functional theory calculations suggest that it results from the hydrogen bonding to the oxo group. We have also demonstrated that the oxidized TDO was activated via a homolytic cleavage of the O-O bond of ferric hydroperoxide intermediate via a substrate dependent process to generate a ferrous TDO. We proposed a peroxide activation mechanism of the oxidized TDO. The TDO has a relatively high redox potential, the protonated state of the proximal histidine upon substrate binding as well as a common feature of the formation of ferric hydroxide species upon substrate or substrate analogues binding. Putting these together, we have proposed a substrate-based activation mechanism of the oxidized TDO. Our work also probed the role of histidine 72 as an acid-base catalyst in the active site. In H72S and H72N mutants, one water molecule plays a similar role as that of His72 in wild type TDO. MauG is a c-type di-heme enzyme which catalyze the biosynthesis of the protein-derived cofactor tryptophan tryptophylquinone. Its natural substrate is a monohydroxylated tryptophan residue present in a 119-kDa precursor protein of methylamine dehydrogenase (MADH). We have trapped a novel bis-Fe(IV) intermediate from MauG, which is remarkably stable. A tryptophanyl radical intermediate of MADH has been trapped after the reaction of the substrate with the bis-Fe(IV) intermediate. Analysis by high-resolution size-exclusion chromatography shows that MauG can tightly bind to the biosynthetic precursor and form a stable complex, but the mature protein substrate does not.
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Soligon, Olivier. "Modélisation et animation du buste humain pour la compression de séquences d'images visiophoniques." Rennes 1, 1998. http://www.theses.fr/1998REN10043.
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Danialdoss, S. "Radical cyclisation based approaches to 9-pupukeanone and lignan precursors." Thesis, Indian Institute of Science, 1996. http://hdl.handle.net/2005/121.
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Application of radical reactions in the organic synthesis for the formation of carbon-carbon bond has dramatically increased over the last fifteen years by virtue of their high degree of chemo-, regio- and stereoselectivity. The present thesis entitled "Radical Cyclisation based Approaches to 9-pupukeanone and Lignan Precursors" describes the application of radical reactions in the synthesis of isotwistane carbon framework present in pupukeananes, and b-arylmethylbutyrolactones, established precursors of various types of lignans. For convenience, the results are presented in two chapters, & ( I ) Radical annulation approach to chiral analogues of 9-pupukeanones; (2) Synthesis of (+-)-enterolactone and lignan precursors; and an appendix entitled 'Chiral synthons from (R)- carvone'. In each Chapter the compounds are sequentially numbered (bold and double underlined), and references are marked sequentially as superscripts and listed at the end of the Chapter. All the figures were obtained by direct xerox of the originaltNMR and muss spectra, and in some of them uninformative areas have been cut to save the space.
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Ratera, Bastardas Imma. "Ferrocene-Based Polychlorotriphenylmethyl radical: A new approach towards multiproperty materials." Doctoral thesis, Universitat Autònoma de Barcelona, 2002. http://hdl.handle.net/10803/3149.
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Al llarg d'aquesta tesi com a part del esforç general per tal d'extendre el nombre de materials moleculars que combinin dues o més propietats en la mateixa molècula, s'ha desenvolupat la síntesi i caracterització d'una nova sèrie de metal.locens (ferrocens i rutenocens) connectats a mono-bi- i tri- radicals polyclorotrifienilmetílics els quals han provat que realment és possible de modular les seves propietats mitjançant el canvi de capacitats donadores dels metalocens, de capacitats acceptores de les unitats radicalàries així com també el canvi del pont. S'han estudiat les propietats magnètiques dels diferents mono- bi- i tri- radicals mitjançant les tècniques d'EPR i SQUID. A partir de les dades obtingudes pels biradicals estudiats, es pot concloure que el pont 1,1'-ferrocenilè actua com a acoblador ferromagnètic entre les dues unitats radicalàries connectades a ell. Quan el ferrocè és substituït amb grups metílics o bé és substituït per un rutenocè, l'acoblament magnètic entre les dues unitats radicalàries desapareix mostrant-se un comportament paramagnètic al llarg de tot el rang de temperatures mesurat. A partir de les dades de susceptibilitat magnètica dels monoradicals s'obtenen valors de magnetització molt alts a temperatura ambient els quals són un indici de la significant contribució orbitàlica de la fracció de Fe (III) per sobre del valor del spin orgànic sol. Aquest resultat suggereix un fenomen de transferència electrònica intramolecular entre el ferrocè i la unitat radicalària. A més a més, per un dels monoradicals sintetitzats, també se n'ha estudiat la isomerització trans - cis tant tèrmica com fotoinduïda mitjançant la tècnica de UV/Vis, ESR spectrosocopy així com també de cromatografia d'HPLC. Aquesta isomerització genera un procés d'autoassemblatge induït tan tèrmica- com fotoquímicament d'un sol sentit i representa un exemple molt interessant d'un sistema fotomagnètic basat en un fenomen supramolecular en el qual una espècie doblet es convertida a una espècie singlet.
Aquesta família de radicals policlorotrifenilmetílics units a un ferrocè també presenten un fenomen de transferència electrònica intramolecular del qual se'n pot modular la seva energia fàcilment mitjançant el canvi de substituents de la unitat donadora, acceptora o fins i tot canviant la naturalesa del dissolvent. Mesures d'absorció espectroscòpiques de temps de resolució de pico-segons ens han permès observar i monitoritzar per primera vegada l'espècie de càrregues separades la qual ens confirma per primera vegada el fenomen de transferència electrònica intramolecular fotoinduït. També ha estat descrit per primera vegada un nou exemple de tautomerisme de valència que combina un radical orgànic com a grup acceptor i un ferrocè com a grup donador.
Finalment, també s'ha comprovat que els radicals policlorotrifenilmetílics constitueixen un sèrie de compostos de capa electrònica oberta molt atractiva que combina elevades respostes d'ONL amb bones estabilitats químiques, tèrmiques i foto-òptiques, gràcies al seu caràcter octupolar. Els sistemes de ferrocens connectats a unitats radicalàries policlorotrifenilmetíliques també exhibeixen intenses respostes d'ONL les quals poden ser modulades mitjançant el canvi de capacitat donadora del metal.locè o accpetora del radical.
This thesis as part of a general effort aimed at extending the range of molecular materials combining two properties in the same molecule, has developed the synthesis and characterization of new series of metallocene (ferrocene and ruthenocene) based polychlorotriphenylmethyl mono, bi- and tri- radicals proving that it is possible their tuning by changing the donor ability of the metallocene unit, the acceptor ability of the radical unit and the nature of the bridge. The magnetic properties of different mono, bi and tri radicals have been studied by EPR and SQUID. From the magnetic data of the biradicals studied, it is conclude that the 1,1'-ferrocenylene bridge acts as a ferromagnetic coupler between the two radical units connected to it. When the ferrocene unit is substitute with methyl groups or it is changed for a ruthenocene unit, the magnetic exchange vanishes showing a paramagnetic behaviour in all the temperature range. From the magnetic susceptibility data for the monoradicals an outsized values of magnetization at room temperature is observed, which it is an indication of significant orbital contributions of the Fe(III) fraction over the spin value. This result suggests a temperature dependent intramolecular electron transfer phenomenon between the ferrocene and the radical unit. In addition, the thermal and photoinduced trans to cis isomerization of one of the monoradicals has been monitored by UV/Vis and ESR spectrosocopy and also followed by HPLC chromatography. This one-way thermal and photoinduced self-assembly process represents an interesting example of a photomagnetic system based on a supramolecular phenomenon in which a doublet species is converted into a singlet one.
Such ferrocene-polychlorotriphenylmethyl radicals present intramolecular electron transfer phenomenon which energy can be easily tuned by changing the substitutents of the donor or acceptor units or even the nature of the solvent. Picosecond time resolved absorption spectroscopy measurements allow us observing and monitoring for the first time the charge separation state that confirms the photoinduced electron transfer phenomena. It has also been described for the first time a novel valence tautomeric example combining an organic radical as acceptor unit and a ferrocene unit as the donor group.
Finally, it has been proved that polychlorotriphenylmethyl radicals constitute a very attractive open-shell series that combines both a high NLO response and good chemical, thermal, and photo-optical stabilities, thanks to their octupolar character. Ferrocene based polychlorotriphenylmethyl radicals systems also exhibits intense NLO responses that can be modulated at will simply tuning the donor and acceptor capabilities of the ferrocene and radical units.
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Mateo-Alonso, Aurelio. "Radical-anions of macrocyclic 1,6 dialkoxyphenazines as chiral electrogenerated bases." Thesis, Queen Mary, University of London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.407425.
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Basak, A. "Synthetic and biosynthetic studies based on radical and related processes." Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370310.
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Ho, Win Fung. "EPR spin-trapping studies of radical reactions with DNA bases." Thesis, University of York, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245967.
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Sadeghipour, Mitra Jr. "Hydrocarbon Functionalization via a New Free Radical-Based Condensation Reaction." Diss., Virginia Tech, 1998. http://hdl.handle.net/10919/30627.
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A new free radical chain process for the allylation of
hydrocarbons and some other substrates utilizing
substituted allyl bromides (R-H + C=C-C-Br -> R-C-C=C + HBr)
has been developed. Good to excellent yields were observed
in all cases. Kinetic chain measurements and competition
experiments were performed in order to elucidate the
mechanism of the reaction. Overall, the results are
consistent with a free radical chain process with bromine
atom as the chain carrier. Substitution effects on the
reactivity of the allyl bromides (CH2=C(Z)CH2Br) and their
influence on the overall reaction rate were studied by
conducting several competition experiments. The relative
rate constants for addition of benzyl radical to
CH2=C(Z)CH2Br are: Z=CN(180), COOEt(110), Ph(65), H(1.0).
The trend of electronegativity/reactivity of these
reactions was very similar to that reported for addition
of benzyl radical to substituted alkenes. Other than alkyl
aromatics (PhCH3, PhCH(CH3)2), other substrates (i.e.,
2- propanol, phenyl cyclopropane) were also tested for
this allylation reaction. The magnitude and scope of
these reactions, and their synthetic utility is discussed.Ph. D.
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Yutronkie, Nathan. "Designing Molecular Materials Through Thiazyl-Based Radicals." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/41202.
Full textAbstract:
Neutral molecular radicals have received increasing attention as building blocks for functional molecular materials owing to their intrinsic conductive and magnetic properties. However, for these systems to be technologically viable, the molecular framework must be capable of stabilizing the unpaired electron, but also enable a degree of control and modulation of the desired properties. To achieve these goals, the design of the radical template requires consideration of the intrinsic effects on the electronic structure and those from a supramolecular perspective. In that regard, thiazyl radicals are promising candidates, as their physical attributes can be tuned systematically for the application at hand.
In the pursuit of tunable thiazyl frameworks, two thiatriazinyl radicals have been synthesized and functionalized with heteroaromatic substituents. The contrasting nature between the attached thienyl and pyridyl substituents was evident upon establishing the preparative routes towards the neutral radical, and further demonstrated when the radicals were characterized spectroscopically. Structural analysis has emphasized the ability for the heteroaromatic moieties to direct the assembly of molecules into different supramolecular arrangements, in addition to self-associating into tightly bound structures.
While dimerization voids the spin properties of these radicals, the redox-versatile thiatriazinyls were designed to explore the physical properties originating from metal coordination. Using the more robust anionic precursor, a dinuclear dysprosium complex was isolated and structurally analyzed, where oxidation of the ligand occurred in the process. A mechanism towards the self-assembly of the complex has been proposed by NMR studies using the isostructural yttrium analogue, which has provided insights on the metal-ligand reactivity. Furthermore, single-molecule magnet behaviour was observed for the dysprosium complex following magnetic investigations.
In contrast to thiatriazinyls, the resonance-stabilized pyridine-bridged bisthiadiazinyls can remain undimerized in the solid state. Three derivatives have been developed with thienyl attachments and vary by the atomic substitution at the basal carbon position (i.e., R = H, F, Cl). Solution measurements illustrated spin delocalization extending across the π-framework, while halogenation provided a handle to fine-tune the energies of frontier molecular orbitals. Moreover, the ability of the thienyl rings to engage in various interactions was manifested in the polymorphic behaviour for each derivative. The solid-state structures were analyzed from single-crystal X-ray diffraction and highlighted the range of supramolecular architectures afforded by these systems.
Lastly, two crystallographic phases of a bisdithiazolyl derivative were isolated selectively, such that the low-temperature phase possess an unprecedented high-symmetry trigonal space group. The mix-matched sizes of the beltline substituents afforded a honeycomb arrangement of stacked radicals. Magnetic measurements depicted a transition to an antiferromagnetically ordered state below 8 K, from which a high-temperature series expansion function was developed to model the magnetic data. Analysis of the results suggest the presence of two equivalent spin-spiral sublattices spanning across the crystal lattice three-dimensionally.
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Silva, Robson Pinho da. "Comportamento redox e detecção voltamétrica de neurotransmissores, nitrito, derivados purínicos e nitrofural em sensores eletroquímicos à base de carbono." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/46/46136/tde-02052013-102258/.
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Sistemas químicos capazes de produzir radicais livres OH• e O2•-, responsáveis por danos no DNA, foram estudados em diversos tipos de eletrodos de carbono previamente modificados. Nitrofural, RNO2, foi reduzido mono eletronicamente ao seu respectivo nitro ânion radical, RNO2•-, em eletrodo de pasta de carbono modificado superficialmente com um filme de guanina. O nitro ânion radical atacou a guanina imobilizada na superfície do eletrodo e, esta interação in situ, resultou na formação de cátions radicais de guanina (G+•), que ao interagirem com a guanina (G), foram identificados pelo pico de oxidação em voltametria pulso diferencial, VPD, nas formas diméricas de guanina na região positiva de potencial. Os outros sistemas estudados se referem ao desenvolvimento de novos eletrodos de carbono modificados ou ainda a utilização procedimentos de modificações desenvolvidas anteriormente, para a detecção de várias moléculas de importância biológica. O ácido ascórbico (AA), ácido úrico (AU), xantina (XA) e hipoxantina (HX) foram detectados simultaneamente em eletrodo de grafite pirolítico, previamente modificado em solução de dopamina (EGPD), utilizando VPD. Os picos de oxidação, obtidos por voltametria cíclica foram detectados em 51; 393; 765 e 1080 mV vs Ag / AgCl, KCl(sat) para AA, AU, XA e HX, respectivamente. O limite de detecção para XA em presença de 5,0 x10-5 mol L-1 de HX foi 2,3 x10-6 mol L-1 (com sensibilidade de 2,8 A mol-1 L cm2), enquanto que o limite de detecção para HX na presença de 5,0 x10-5 mol L-1 de XA foi de 5,6 x10-6 mol L-1 (com sensibilidade de 1,4 A mol-1 L cm-2). XA e HX foram determinadas em amostras de urina e os valores encontrados foram 0,47 µmol L-1 e 5,9 mol L-1, respectivamente. Serotonina (5-HT) e dopamina (DA) foram determinadas simultaneamente em eletrodo de carbono vítreo, previamente modificado em solução de serotonina (GCE - 5HT). A serotonina foi detectada em 379 mV vs Ag / AgCl, KCl(sat), 31 mV menos positivo daquele observado em eletrodo de carbono vítreo (410 mV), enquanto DA foi detectada a 200 mV. Nenhuma interferência foi observada na presença de (AA), tirosina (Tyr), epinefrina (EP) e noradrenalina (NE). Finalmente, na última etapa do presente trabalho lignina, extraída a partir de licor de Kraft, foi solubilizada em acetonitrila / H2SO4 e a solução resultante utilizada para dispersar nanotubos de carbono de parede múltipla, NTCPM. Esta suspensão foi empregada para modificar a superfície de um eletrodo de carbono vítreo, posteriormente utilizado na detecção de nitrito por VPD no intervalo de concentração de 4,0 x 10-6 ≤ [NO2-] ≤ 8, 0 x 10-5 mol L-1. O complexo formado entre neocuproina e Cu (I), um composto em potencial para geração de radicais livres e promoção de lesões no DNA, foi sintetizado e caracterizado.Chemical systems, which are able to produce OH• and O2•- free radicals, responsible for damage in DNA, were studied at different carbon modified electrode surfaces. Guanine carbon paste modified electrode was used to promote the nitrofural (RNO2) monoelectronic reduction to its respective nitro anion radical, RNO2•-, which attacked guanine immobilized on the electrode surface. The interaction in situ promoted the formation of guanine cation radicals (G+•) between guanine (G), after a dimerization process, were detected in the positive potential range by Differential Pulse Voltammetry, DPV. The other studied systems refer to development of new carbon modified electrodes or utilization of carbon modified electrodes, previously described, for the detection of several important biological molecules. Ascorbic acid (AA), uric acid (UA), xanthine (XA) and hypoxanthine (HX) were simultaneously detected at pyrolytic graphite electrode, previously modified into dopamine solution (EGPD), using DPV. The oxidation peak potentials, were obtained by cyclic voltammetry at 51; 393; 0.765 and 1080 mV vs Ag/AgCl, KCl(sat) for AA, UA, XA and HX, respectively. The detection limit for XA in presence of 5.0 x10-5 mol L-1 HX was 2.3 x10-6 mol L-1 (with sensibility of 2.8 A mol-1 L cm-2), while the detection limit for HX in presence of 5.0 x10-5 mol L-1 XA was 5.6 x10-6 mol L-1 (with sensibility of 1.4 A mol-1 L cm-2). XA and HX were determined in urine samples and the values founded were 0.47 µM e 5.9 µM, respectively. Serotonin (5-HT) and dopamine (DA) were simultaneously detected at glassy carbon electrode, previously modified in serotonin solution (ECV - 5HT). Serotonin was detected at 379 mV vs Ag/AgCl, KCl (sat), 31 mV less positive potential than that observed at bare glassy carbon electrode (410 mV), while DA was detected at 200 mV. No interference was observed in presence of (AA), tyrosine (Tyr), epinephrine (EP) and noradrenaline (NE). Finally, in the last stage of this work, lignin, extracted from Kraft liqueur, was solubilized in acetonitrile/H2SO4 and used to disperse multi-wall carbon nanotubes, MWNTC. This suspension was used to modify the glassy carbon electrode surface and nitrite was detected, by DPV in the concentration range of 4,0 x 10-6≤ [NO2-] ≤ 8,0 x 10-5 mol L-1. The complex formed between neocuproina and Cu (I), a compound which can produce free radicals and thereby cause damage to DNA, was synthesized and characterized.
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Wen, Xin. "The Utilization of Sulfonylhydrazones as New Radical Precursors for Asymmetric Radical C–H Alkylation via Co(II)-Based Metalloradical Catalysis." Thesis, Boston College, 2019. http://hdl.handle.net/2345/bc-ir:108292.
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Thesis advisor: X. Peter ZhangAsymmetric C–H functionalization represents one of the central topics in modern organic chemistry, which allows for the direct installation of functional groups onto ubiquitous C–H bonds in organic molecules. Among numerous elegant strategies, transition metal-catalyzed C–H alkylation with diazo compounds represents one of the most powerful methods for C–C bond formation. Different from Fischer metallocarbene-based C–H insertion reactions, cobalt(II)-based metalloradical catalysis (MRC) is recently proven to be capable of activating acceptor/acceptor diazo compounds for radical C–H alkylation reactions via H-atom abstraction. In this dissertation, we have developed several systems by utilizing less-explored aryl and alkyl diazomethanes as new radical precursors for highly enantioselective radical C–H alkylation reactions, which permit the efficient synthesis of different optically active heterocyclic compounds. First, we have demonstrated the feasibility of using aryl aldehyde-derived sulfonylhydrazones as new radical precursors for enantioselective radical C–H alkylation to synthesis enantioenriched 2,3-dihydrobenzofuran derivatives. Notably, a general and mild way for in situ generation of diazo compounds have been identified by using 2,4,6-triisopropyl sulfonyl hydrazone as diazo precursor, which allow us to regulate the reaction temperature to achieve the high enantioselectivity for the desired radical reactions. Second, the utility of Co(II)-based MRC has been further highlighted by enantioselective indoline synthesis. Through the design and synthesis of new catalysts, the system is shown to have a broad spectrum of substrate scope, forming various 2-substituted indolines with up to 98% yield and 96% ee. A series of mechanistic studies further support the underlying stepwise radical alkylation pathway. Finally, we further expand the applicability of MRC to even more challenging diazo compounds, aliphatic diazomethanes. Starting from alkyl aldehyde-derived sulfonylhydrazones as diazo precursors, the Co(II)-based radical alkylation reactions allow for the enantioselective synthesis for common 2-substituted tetrahydrofuran structures with high yields and excellent enantioselectivities
Thesis (PhD) — Boston College, 2019
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry
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LACERDA, Estefane George Macedo de. "Model Selection of RBF Networks Via Genetic Algorithms." Universidade Federal de Pernambuco, 2003. https://repositorio.ufpe.br/handle/123456789/1845.
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Previous issue date: 2003Um dos principais obstáculos para o uso em larga escala das Redes Neurais é a dificuldade de definir valores para seus parâmetros ajustáveis. Este trabalho discute como as Redes Neurais de Funções Base Radial (ou simplesmente Redes RBF) podem ter seus parâmetros ajustáveis definidos por algoritmos genéticos (AGs). Para atingir este objetivo, primeiramente é apresentado uma visão abrangente dos problemas envolvidos e as diferentes abordagens utilizadas para otimizar geneticamente as Redes RBF. É também proposto um algoritmo genético para Redes RBF com codificação genética não redundante baseada em métodos de clusterização. Em seguida, este trabalho aborda o problema de encontrar os parâmetros ajustáveis de um algoritmo de aprendizagem via AGs. Este problema é também conhecido como o problema de seleção de modelos. Algumas técnicas de seleção de modelos (e.g., validação cruzada e bootstrap) são usadas como funções objetivo do AG. O AG é modificado para adaptar-se a este problema por meio de heurísticas tais como narvalha de Occam e growing entre outras. Algumas modificações exploram características do AG, como por exemplo, a abilidade para resolver problemas de otimização multiobjetiva e manipular funções objetivo com ruído. Experimentos usando um problema benchmark são realizados e os resultados alcançados, usando o AG proposto, são comparados com aqueles alcançados por outras abordagens. As técnicas propostas são genéricas e podem também ser aplicadas a um largo conjunto de algoritmos de aprendizagem
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Wirth, Manfred P., and Oliver W. Hakenberg. "Curative Treatment of Prostate Cancer." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-133890.
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The guidelines for the curative treatment of prostate cancer presented by the German Society of Urology are discussed. They are based on the current knowledge of the outcomes of surgical and radiotherapeutic treatment for prostate cancer. Radical prostatectomy is recommended as the first-line treatment for organ-confined prostate cancer in patients with an individual life expectancy of at least 10 years. Radiotherapy can be considered as an alternative treatment modality, although current knowledge does not allow a definite assessment of the relative value of radiotherapy compared to radical prostatectomy. Locally advanced cT3 prostate cancer is overstaged in about 20% and curative treatment is possible in selected cases. Guidelines represent rules based on the available evidence. This implies that exceptions must be made whenever appropriate and that guidelines have to be reviewed regularly as new information becomes availableDieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich
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Simões, Alexandre da Silva. "Aprendizado não-supervisionado em redes neurais pulsadas de base radial." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/3/3141/tde-15092006-153353/.
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Redes neurais pulsadas - redes que utilizam uma codificação temporal da informação - têm despontado como uma nova e promissora abordagem dentro do paradigma conexionista emergente da ciência cognitiva. Um desses novos modelos é a rede neural pulsada de base radial, capaz de armazenar informação nos tempos de atraso axonais dos neurônios e que comporta algoritmos explícitos de treinamento. A recente proposição de uma sistemática para a codificação temporal dos dados de entrada utilizando campos receptivos gaussianos tem apresentado interessantes resultados na tarefa do agrupamento de dados (clustering). Este trabalho propõe uma função para o aprendizado não supervisionado dessa rede, com o objetivo de simplificar a sistemática de calibração de alguns dos seus parâmetros-chave, aprimorando a convergência da rede neural pulsada no aprendizado baseado em instâncias. O desempenho desse modelo é avaliado na tarefa de classificação de padrões, particularmente na classificação de pixels em imagens coloridas no domínio da visão computacional.Pulsed neural networks - networks that encode information in the timing of spikes - have been studied as a new and promising approach in the artificial neural networks paradigm, emergent from cognitive science. One of these new models is the pulsed neural network with radial basis function, a network able to store information in the axonal propagation delay of neurons. Recently, a new method for encoding input-data by population code using gaussian receptive fields has showed interesting results in the clustering task. The present work proposes a function for the unsupervised learning task in this network, which goal includes the simplification of the calibration of the network key parameters and the enhancement of the pulsed neural network convergence to instance based learning. The performance of this model is evaluated for pattern classification, particularly for the pixel colors classification task, in the computer vision domain.
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Souza, Andreia Cristina Breda de. "Aproximação fisionômica pericial através de função de base radial hermitiana." Universidade do Estado do Rio de Janeiro, 2014. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=9045.
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A aproximação fisionômica é o método que busca, a partir do crânio, simular a fotografia de um indivíduo quando em vida. Deve ser empregada como último recurso, na busca de desaparecidos, quando não houver possibilidade de aplicação de um método válido de identificação. O objetivo deste estudo foi obter a aproximação fisionômica, a partir de um crânio seco e de tomografia computadorizada multislice de indivíduos vivos, através da função de base radial hermitiana (FBRH). Constituiu-se também em avaliar o resultado da mesma quanto ao reconhecimento. Na primeira etapa do estudo, foi utilizada a imagem escaneada de um crânio seco, de origem desconhecida, com o intuito de avaliar se a quantidade de pontos obtidos seria suficiente para aplicação da FBRH e consequente reconstrução da superfície facial. Na segunda fase, foram utilizadas três tomografias de indivíduos vivos, para análise da semelhança alcançada entre a face escaneada e as aproximações faciais. Nesta etapa, foi aplicada uma associação de diferentes metodologias já publicadas, para reconstrução de uma mesma região da face, a partir de um mesmo crânio. Na última etapa, foram simuladas situações de reconhecimento com familiares e amigos dos indivíduos doadores das tomografias. Observou-se que a metodologia de FBRH pode ser empregada em aproximação fisionômica. Houve reconhecimento positivo nos três sujeitos estudados, sendo que, em dois deles, os resultados foram ainda mais significativos. Desta forma, conclui-se que a metodologia é rápida, objetiva e proporciona o reconhecimento. Esta permite a criação de múltiplas versões de aproximações fisionômicas a partir do mesmo crânio, o que amplia as possibilidades de reconhecimento. Observou-se ainda que a técnica não exige habilidade artística do profissional.Facial approximation works by building the visual face up from the skull. This method should be performed as last resort, to carry out for missing persons, when there is no other primary identification method avaliable. The purpose of this study was to introduce a new computerized method with hermite radial basis function (HRBF) for facial approximation using dry skull and computed tomography (CT). The same was also evaluated as a result of the recognition. Firstly, a scan of a dry unidentified skull image was used in order to assess if the amount of points would be sufficient for HRBF methodology and subsequent reconstruction of the facial surface. In second, three CT scans of living individuals were used to evaluate the similarity achieved between the real face scanned and facial approximations. An association of different facial structures reconstruction techniques already published for the same region of the face was applied for the same skull. Moreover, some situations from developed facial approximations were simulated, as recognition by a relative or parent, on a face pool-test. Results from the study showed that the purposed methodology can be used for facial approximation. At the three cases a correct approximation identification as one of a few possible matches to the missing person happened. In two of them, the results were consistently better at identifying the correct approximation. In conclusion, the proposed methodology is fast, objective and reaches visual identification. It is possible to perform multiple versions of the same skull, changing the selected data into the system, which maximizes the chances of establishing recognition of the target face. It was also observed that the technique does not need artistic interpretation.
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Lay, Alexander Kit. "New π-electron donor systems based on 1,4-dithin derivatives." Thesis, Durham University, 1997. http://etheses.dur.ac.uk/4725/.
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A review of organic, π-electron donor molecules is given. The focus is on non- tetrathiafulvalene based systems. Polycyclic arenes, thioalkyl substituted arenes, chalcogenated fulvalenes, peri-dichalcogen bridged polycyclic arenes and heteroarenes are covered. Various π-electron donor molecules based on acenaphtho[ 1,2-b][ 1,4]-dithin have been synthesised via various methodologies. The redox properties of these molecules, as studied by cyclic voltammetry, provide evidence that these species are efficient π-electron donors. A selection of these compounds have also been studied by Electron Spin Resonance. Two ring expansion methodologies have been utilised in the synthesis of acenaphtho[l,2-b][l,4]-dithin based systems from 1,2-dithiols. Complexation of 7,12- dithia-benzo[k]fluoranthene, thus synthesised, with 2,5-dibromo-7,7,8,8-tetracyano-p- quinodimethane and iodine (I(_4) counter ion) yielded highly crystalline but poorly conducting salts.1,2-Dibromoacenaphthylene and benzo-l,2-dithiolate species have been reacted to form new 7,12-dithia-benzo[k]fluoranthene derivatives, two of which have been studied by X-ray diffraction. The versatile oligo(l,3-dithiole-2,4,5-trithione) compound has been used to generate various compounds containing the 1,4-dithiin ring including 8,9- di(methylsulfanyl)acenaphthyleno[l,2-b][l,4]dithine, which forms complexes with 7, 7,8,8-tetracyano-p-quinodimethane, 2,5-dibromo-7,7,8,8-tetracyano-p-quinodimethane and iodine (I(_7) counter ion) all three of which have been studied by X-ray diffraction. A novel 1,2,4-trithiolane has also been synthesised and characterised by X-ray diffraction.
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Ledoux, Valentin. "Matériaux nanocomposites à base d'oxydes conducteurs pour la génération d'énergie électrique en milieux humides et pour de nouvelles applications électrocatalytiques." Thesis, IMT Mines Alès, 2019. http://www.theses.fr/2019EMAL0002.
Full textAbstract:
Un comportement « inhabituel » des anodes d'oxyde dans les milieux aqueux, par rapport aux anodes métalliques, a commencé à attirer l'attention des chercheurs dès les années 1960. Pendant le processus d'activation, les électrons placés dans la bande de valence (VB) d'un corps semi-conducteur quittent leur niveau d'énergie et se déplacent vers la bande de conduction (CB) formant ainsi des trous électroniques capables de procéder à une oxydation directe des anions d’hydroxyles adsorbés , les transformant ainsi en radicaux hydroxyles HO•, qui sont des agents oxydants extrêmement puissants. Cette considération permet d’expliquer pourquoi l'oxydation des polluants organiques dans l'eau est toujours plus élevée sur les anodes d'oxyde que sur les anodes métalliques. Le cycle réactionnel est le suivant :H2O + MOx [site « Catalytique »] MOxHO•ads + H+ + 1 e- puis MOxHO•ads + RH MOx + H2O + R’Bien que largement utilisé dans les procédés de dépollution de l’eau par électrocatalyse, le mécanisme décrivant les interactions entre les anodes d’oxydes et l’eau est mal connu.L’ambition de cette thèse est de démontrer la faisabilité de la récupération de charges électriques à partir de l’eau en utilisant une anode d’oxyde métallique, SnO2:F a été choisi comme anode modèle. La démonstration de cette hypothèse passe en 5 étapes : 1.Comprendre pourquoi l’eau est capable de se comporter en tant qu’agent réducteur et donc partager sa charge électrique avec des consommateurs extérieurs au travers des surfaces d’oxydes métalliques. 2.Conceptualiser le mode d’action des anodes d’oxydes dans les milieux humides. Développer une vision claire sur le mécanisme de ce phénomène, l’étudier de façon détaillée et confirmer objectivement ses étapes principales par l’intermédiaire de résultats expérimentaux. 3.Conceptualiser, tant du point de vue des compositions chimiques que des propriétés physico-chimiques et électro-physiques, des matériaux actifs prometteurs applicables en tant que générateurs de charges électriques élémentaires à partir des milieux humides. 4.Choisir, élaborer et tester des matériaux actifs appropriés, c’est-à-dire répondant aux exigences, en terme de compositions chimiques et de propriétés électro-physiques, fixées au cours du point précédent. 5.Conclure par la proposition d’une méthode d’estimation de l’efficacité énergétique du procédé en cours de développement et sur les perspectives d’applicationsAn "Unusual" behavior of oxide anodes in aqueous media, compared with metal anodes, began to attract the attention of researchers as early as the 1960s. During the activation process, electrons placed in the valence band (VB) of a semiconductor material leave their energy level and move towards the conduction band (CB) thereby forming electronic holes able to proceed at the direct oxidation of adsorbed hydroxyl anions, thereby transforming them into hydroxyl radicals HO•, which are extremely powerful oxidizing agents. This consideration makes it possible to explain why the oxidation of organic pollutants in water is always higher on the oxide anodes than on the metal anodes. The reaction cycle is as follows:H2O + MOx ["Catalytic" site] MOx•HO•ads + H+ + 1 e- then MOx•HO•ads + RH MOx + H2O + R’Although widely used in electrocatalysis water depollution processes, the mechanism describing the interactions between oxide anodes and water is poorly understood.The ambition of this thesis is to demonstrate the feasibility of recovering electrical charges from water using a metal oxide anode, SnO2:F was chosen as the model anode. The demonstration of this hypothesis follows 5 steps: 1. Understand why water is able to behave as a reducing agent and therefore share its electric charge with external consumers through metal oxide surfaces. 2.Conceptualize the mode of action of oxide anodes in humid environments. Develop a clear vision on the mechanism of this phenomenon, study it in detail and objectively confirm its main stages through experimental results. 3.Conceptualize, from the point of view of chemical compositions as well as physicochemical and electro-physical properties, promising active materials applicable as generators of elementary electrical charges from wetlands. 4.Choose, develop and test appropriate active materials, that is to say, meet the requirements, in terms of chemical compositions and electro-physical properties, fixed in the previous point. 5.Conclude by the proposal of a method of estimating the energy efficiency of the process under development and the prospects of applications