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Kegel, Mark Steven, and n/a. "Fibres from recycled post consumer PET/nylon 6 blends." Swinburne University of Technology, 2006. http://adt.lib.swin.edu.au./public/adt-VSWT20070606.111448.
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The objective of this project was to develop blends based upon post consumer RPET and N6, and to evaluate the suitability of these blends to form fibres for the end use in carpet fibre.
In the work carried out it was found it is possible to spin RPET/N6 biconstituent fibres over a wide range of blend ratios. All the blends studied have diminished physical properties when compared to those of pure RPET and N6. The processability of these blends also deteriorated due to the large increases in normal forces which manifests in extrusion equipment as die swell that often results in melt fracture.
It has been shown that the morphology of the fibre controls the degree of decay in properties and die swell at the spinnerette. The blends that are rich in one phase, with the secondary phase distributed as elongated fibrils have shown better physical performance and improved processing compared to the blends 70/30 � 30/70, which have poorer properties and increased die swell due to there co-continuous morphology. In quiescent studies, the physical properties of the blends have had little deviation from those predicted using a rule of mixtures line. In and around the 50% RPET blend, die swell was observed to be extreme and this makes fibre spinning difficult. It was found that this was caused by a loss in viscosity in the blends and a general increase in normal forces in response to applied shear. The die swell phenomenon is a rheological characteristic of the blends, which was inevitably caused by internal capillary flow of one component in the other.
IR spectroscopy has shown that there is little to no in-situ compatibilisation occurring during simple melt processing. However, it was found that significant interfacial compatibilisation could be achieved through solid stating N6/RPET blends. The FTIR spectra for solid state blends in figure 4.51 has shown absorbency in the 3300 cm-1 region after all free N6 was removed. This indicates that in-situ compatibilisation has occurred between the phases in the solid stating process and it is a time dependent reaction.
The Burgers and Koltunov models can be used to predict the creep behaviour of the fibre blends studied. The Burgers model provides greater accuracy for longer-term exposure to stress.
From the thermal results, the solid stating process significantly affects the melting and crystallisation out of the melt and the ultimate level of crystallinity. The contribution of the copolymer in these changes appears to be small. The physical strength of the fibres made on the laboratory line was only marginally lower than those made on a factory line. The morphology of the mid-range blends is co-continuous and that of the N6 and RPET rich blends is dispersed droplet morphology.
Based on the finding, a N6 rich blends and in particular the 10% RPET blend is the most suitable for further commercial development as its processing, physical performance and post spinning processing closely resemble the pure N6 currently in use. It has provided performance and consistency throughout the processing and testing we have conducted.
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López, Cartagena Clara Lucy, Verastegui Franz Ricardo Jäeger, and Carranza Karina Ramírez. "Plan para mejorar el abastecimiento de materia prima reciclada en empresa productora de RPET." Master's thesis, Universidad del Pacífico, 2019. http://hdl.handle.net/11354/2361.
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La Unidad de negocio de reciclado pertenece a una empresa que se desarrolla en el sector económico del plástico como proveedor líder en la fabricación de envases rígidos en la región andina, Centroamérica y el Caribe. De modo que la presente tesis tiene el objetivo de mejorar el abastecimiento de la Unidad de negocio de reciclado de la principal productora de envases PET y resina reciclada del país. Con este propósito, se debe considerar que una de sus dos líneas de producción utiliza el 40% de su capacidad instalada teórica debido a la falta de materia prima (botella post-consumo reciclada). Esta información se conoce a través de un diagnóstico de su cadena de suministro que utiliza la metodología del Mapa estratégico funcional, que identifica la implementación de centros de acopio como la actividad que mejor se alinea con la estrategia general de la empresa para diversificar las fuentes de abastecimiento. Actualmente, la unidad de reciclado cuenta con un centro de acopio en Ica que ha contribuido con los volúmenes de compra. En ese sentido, se propone la implementación de un segundo centro de acopio en Trujillo que diversifique las fuentes de suministro. Para determinar la ubicación del mismo, se utilizó el modelo de centro de gravedad (Chopra y Meindl 2013), que permitió localizar el punto que minimiza el costo de transporte e incrementa la cantidad de acopio. Posterior a ello, se realizó el análisis cuantitativo y cualitativo que permitió establecer la ciudad que representa la mejor alternativa para la ubicación del centro de acopio, así como su capacidad instalada según el estudio de factor poblacional.
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Lycke, Sara, Lisa Rosell, and Emma Landström. "Bidrar kunskap till hållbara köpintentioner? : En kvantitativ studie om vad som påverar konsumenters köpintentioner till rPET." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-26356.
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Textilindustrin är den mest förorenande industrin efter oljeindustrin och ett mål är därför att arbeta med mer återvunna fibrer. Dock väljs ofta dessa alternativ bort av konsumenter även fast en viss efterfrågan har identifierats. Trots en ökad efterfrågan kopplat till hållbara val så besitter inte konsumenter kunskap kring miljöfrågor kopplade till de hållbara alternativen. Avsaknad av kunskap kan alltså vara en orsak till varför deras åsikter inte återspeglas i konsumtionsvalet, därmed uppstår frågan om det finns ett samband mellan kunskap och köpintentioner, eller vilka variabler som påverkar köpintentioner. Polyester är ett material som är mycket påfrestande för miljön och fortsätter vara populärt att använda. Detta har lett till föroreningar, ett avsevärt ökat utsläpp samt stora mängder PET-avfall till miljön. Produktionen av återvunnen polyester, rPET, är mer miljövänlig än produktion av nyproducerad polyester. Exempelvis, för varje kilo mekanisk återvunnen polyester minskar utsläpp av växthusgaser med 70% jämfört med växthusgasutsläpp orsakade av nyproducerad polyester. Då tidigare studier som använt sig av en omarbetad version av teorin Theory of Planned Behavior har visat att attityder, subjektiva normer, upplevd beteendekontroll samt kunskap påverkar intentioner testar denna studie om så även är fallet när de kommer till köpintentioner till rPET. Genom en kvantitativ enkätundersökning och med hjälp av en omarbetad version av teorin Theory of Planned Behavior undersöks om det finns ett samband mellan modellens variabler och köpintentioner till rPET. Resultatet visar att attityder och upplevd beteendekontroll har ett starkt samband med köpintentioner till rPET samt att det finns ett samband, dock negativt och svagare, mellan objektiv kunskap och köpintentioner till rPET. De andra variablerna, subjektiva normer och subjektiv kunskap, besitter inte ett signifikant samband med köpintentioner till rPET. Fortsättningsvis skiljde sig sambanden för variablerna mellan män och kvinnor.The textile industry is the most polluting industry after the oil industry. Therefore, a goal is to work with more recycled fibers within the textile industry. However, these alternatives are often opted out by consumers despite the fact that a demand has been identified on the market. Previous studies have shown that even though the increased demand is associated with sustainable choices, consumers do not possess knowledge about the environmental issues related to sustainable alternatives. Lack of knowledge can be a reason for why consumers' opinions do not reflect on their consumption choices, hence the question arises whether there is a connection between knowledge and purchase intentions, or which variables do affect the purchase intention. Polyester has a negative impact on the environment but remains popular to use. This has led to pollution, significant increase of emissions, and large amounts of PET waste. The production of recycled polyester, rPET, is however more environmentally friendly than the one of newly produced polyester. For instance, for every kilogram of mechanically recycled polyester, the greenhouse gas emissions are reduced by 70% compared to the greenhouse gas emissions caused by newly produced polyester. By using the revised model Theory of Planned Behavior, previous studies have shown that attitudes, subjective norms, perceived behavioral control and knowledge affects intentions. Thus, this study aims to test whether this is the case or not when it comes to purchasing intention for rPET. By using a quantitative survey and a revised version of the model Theory of Planned Behavior, the revised model explores whether there is a relation between these variables and purchasing intentions towards rPET. The results show that attitudes and perceived behavioral control have a strong relation with purchasing intentions to rPET. Moreover, there is a relation, although negative and weaker, between objective knowledge and purchasing intentions to rPET. However the other variables, subjective norms and subjective knowledge, do not have a significant relation with purchasing intentions to rPET. Furthermore, the relation between the variables differ between the genders.
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Whitt, Michael John-Ross. "Studies to Characterize Heavy Metal Content and Migration From Recycled PolyethyleneTerephthalate." DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1350.
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Packaging Materials account for 31% of the world’s municipal solid waste. Agencies like the Environmental Protection Agency (EPA) and the Agency for Toxic Substances and Disease Registry (ATSDR) are pushing for the increased use of recycled thermoplastic materials. Polyethylene terephthalate (PET) is a commonly recycled thermoplastic which is used to package ready-to-eat fruits and vegetables. Most recycled polyethylene terephthalate (RPET) packaging materials contain heavy metal catalysts, the most common being antimony. The recent increased use of recycled plastic materials has been suspected as the source of increased human heavy metal exposure. In this study, cadmium, chromium, nickel, lead and antimony were quantified in post-consumer RPET rigid containers and films using inductively coupled plasma-atomic emission spectrometry (ICP-AES). Two hundred samples were tested of which 29 were found to be contaminated with heavy metals in the parts-per-million (ppm) range. Chromium was found in all the contaminated sample replicates at an average level of 8.18 ppm. Cadmium was found in all the contaminated samples as well. Lead was found in 90.4% of the contaminated samples and concentrations ranged from a low of 0.02 ppm to a high of 0.36 ppm. Nickel was found in 96.4% of the contaminated samples while antimony was found in 97.6% of the samples. Due to limited sample material, 22 of the 29 contaminated RPET rigid containers and films were tested for heavy metal migration into a 5% citric acid:water solution (w/v) or deionized water. Samples were subjected to prolonged storage at 7.2 or 22.2°C for 1, 7 or 14 days, or were exposed for 5 minutes to microwaves from a 1700-watt microwave oven set to 70% power before analysis. Leachate values were at ppb levels but were often below the ICP-AES Limits of Detection which were at also the ppb level, whether calculated for deionized water or 5% citric acid in water. No measureable levels of heavy metal were detected for any sample exposed to water, regardless of treatment. For samples exposed to 5% citrate and stored or microwaved, only chromium and nickel leached at measurable levels, and the number of RPET’s releasing measurable chromium and nickel increased with microwaving compared to the same plastics stored at 22.2 or 7.2°C. Since leaching was calculated as µg/L of heavy metal lost from the entire inner surface (1021 cm2) of a retail salad bag, actual exposure to heavy metal would be much less than measured in this study as retail fruit and vegetable packages and microwaveable pouches usually contain very little liquid in order to increase food safety. The results therefore suggest the potential for little migration of heavy metal from recycled PET to whole or fresh-cut fruits and vegetables when held at ambient or refrigerated temperatures, or when microwaved.
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Lightfoot, Ruth M. "Retinal pigment epithelial dystrophy (RPED) in the dog." Thesis, Royal Veterinary College (University of London), 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339266.
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Wiezlak, M. K. "Regulation and function of the RPEL protein - Phactr1." Thesis, University College London (University of London), 2013. http://discovery.ucl.ac.uk/1394439/.
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Actin-binding proteins play well established roles in the regulation of actin dynamics and assembly of F-actin based structures involved in cell motility and adhesion. The Phosphatase and actin regulator (Phactr) family of proteins each contain four G-actin binding RPEL motifs and has been found to bind protein phosphatase 1 (PP1) via their C-terminal domain. Their function is not well established and it has been unclear whether G-actin can be their regulator. Members of the Phactr family are highly expressed in the nervous system and in some metastatic cancers. The RPEL domain was previously shown to confer Rho-regulated nuclear shuttling and activation of Serum Response Factor (SRF) coactivator myocardin – related transcription factor A (MRTF-A, also known as MAL/MKL1). MRTF-A is cytoplasmic in unstimulated cells and accumulates in the nucleus upon activation of Rho-actin signalling. In this thesis I show that activation of Rho-actin signalling by serum stimulation induces nuclear accumulation of Phactr1, but not other Phactr family members (Phactr2-4). Actin binding by the three Phactr1 C-terminal RPEL motifs is required for Phactr1 cytoplasmic localisation in resting cells. Phactr1 nuclear accumulation is Importin α−β-dependent. I also reveal that G-actin and Importin α−β bind competitively to nuclear import signals associated with the N- and C-terminal RPEL motifs in Phactr1. All four motifs are required for the inhibition of serum-induced Phactr1 nuclear accumulation by elevated G-actin. G-actin and PP1 bind competitively to the Phactr1 C-terminal region, and expression of Phactr1 C-terminal RPEL mutants that cannot bind G-actin induces actomyosin foci dependent on PP1 binding. In CHL-1 metastatic melanoma cells, Phactr1 exhibits actin-regulated subcellular localisation and is required for stress fibre assembly, motility, and invasiveness. These data support a role for Phactr1 in actomyosin assembly and suggest that Phactr1 G-actin sensing allows its coordination with F-actin availability.
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Niang, Awa. "RPE et relaxation de composites moléculaires bidimensionnels." Toulouse 3, 1994. http://www.theses.fr/1994TOU30153.
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Nous avons etudie par resonance paramagnetique electronique en bande x l'anisotropie de la largeur de raie et du facteur g des composites moleculaires bidimensionnels de type perovskite feuillete nh#3-r-nh#3mx#4. Les mesures ont ete effectuees sur des monocristaux et des poudres en fonction de la temperature (de 4. 2 a 290k). Le temps de relaxation spin-reseau t#1 a egalement ete mesure par la methode de modulation en fonction de la temperature. Les echantillons presentent des structures et des interactions de couplage differentes suivant la nature de l'halogene x, du metal m et du radical organique r. Nous avons analyse l'influence de ces parametres sur le comportement des spins par l'etude des echantillons nh#3-(ch#2)#n-nh#3mx#4 m = (manganese, cuivre. ), x (chlore, brome) et n = 2,3,4,5. Lorsque r est compose de molecules ayant des liaisons insaturees ces materiaux constituent d'excellentes matrices pour des reactions de polymerisation selectives par irradiation ou par traitement thermique. Nous avons effectue des mesures de rpe et de relaxation spin-reseau sur le complexe de propargylamine et de chlorure de cadmium hcc-ch#2-nh#3#2cdcl#4 chauffe. L'interpretation des resultats s'effectue en tenant compte de la forte interaction d'echange presente dans ces echantillons et des differentes interactions de couplage. Les dependances de t#1 sont interpretees en utilisant le modele des trois reservoirs de bloembergen et wang. Les resultats mettent en evidence la diffusion des spins lorsque le metal est le manganese et la presence d'une interaction d'echange antisymetrique modulee par les phonons dans le cas du cuivre. La nature de l'halogene joue egalement un role important dans la dynamique des spins et notamment dans la relaxation spin-reseau. Les resultats obtenus sur hcc-ch#2-nh#3#2cdcl#4 chauffe sous vide mettent en evidence la creation d'un nombre important de centres paramagnetiques due a la disparition des triples liaisons et par consequent une forte interaction d'echange
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Chandler, Aglaia. "The role of RpoT;3 in chloroplast development and gene expression." Thesis, [College Station, Tex. : Texas A&M University, 2005. http://hdl.handle.net/1969.1/ETD-TAMU-1701.
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Stranna, Andrea. "Testing of RPT in pumping mode of operation." Thesis, Norges Teknisk-Naturvitenskaplige Universitet, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-20656.
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In this project two pump mode tests has been carried out on a model RPT in the Waterpower Laboratory at NTNU. The measurement set up and execution of the tests were the same, except for the method of dissipating energy in the system. In the first test one of the feed pumps in the basement was used as energy dissipator. In the second test a throttle valve was used as energy dissipator.The objective has been to see how the Waterpower Laboratory is suited for such a test. It was also important to test the two different dissipation methods and evaluate which should be preferred when performing a pump mode test.During the tests it was observed that the guide vane angle kept changing. When the results were processed it became evident that the variations in guide vane angle during the tests had a big influence on the measured pump curves. Variations in guide vane angle has not previously been observed during turbine mode testing. It is presumed that the variation in guide vane angles is due to play in the guide vane system and the design of the guide vanes. The guide vanes are Francis vanes, and not RPT vanes. It is assumed that it is the sharp trailing edge of the guide vanes that causes turbulence over the vanes in pump mode, thus making the guide vanes move about within the play of the guide vane system. It is suggested that the guide vane system is replaced with an RPT guide vane system for further testing in pump mode.The two dissipation methods tested were both effective. The throttle valve works best for achieving 0 flow, while the feed pump is easier to regulate. None of the methods showed signs of high noise or vibrations, and both may be used for future tests.
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Stein, Roberto de Mello. "RPE em compostos de grafite intercalado com ALCL3." [s.n.], 1985. http://repositorio.unicamp.br/jspui/handle/REPOSIP/277549.
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Orientador: Carlos RettoriTese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin
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Resumo: Nós mostramos que no Composto de Grafite Intercalado com AlCl3, tipo aceitador, a dependência com a temperatura da resistividade no plano e na direção do eixo-c entre 100K e 300K, pode ser obtida experimentalmente através da análise da intensidade e da forma da linha da ressonância de spin dos portadores de carga. Os resultados indicam um comportamento metálico e do tipo salto por ativação térmica para o transporte de carga no plano e no eixo-c, respectivamente. A análise da ressonância no grafite puro apresenta dentro do erro experimental, a dependência com a temperatura esperada para a resistividade no plano e no eixo-c e uma susceptibilidade que independe da temperatura. A dependência da largura da linha é atribuída a dependência com a temperatura da mobilidade dos portadores e da razão entre a probabilidade de transição para "spin-flip" devido ao acoplamento spin-órbita e o espalhamento coulombiano. Para estágios um e sete os parâmetros da ressonância revelam uma transição de fase a 210K e 168K respectivamente
Abstract: We show that the temperature dependence of the in-plane and c-axis resitivities between 100K and 300K for the acceptor AlCl3 - Graphite Intercalated Compounds can be obtained from the analysis of the intensity and lineshape of the resonance in a conduction carrier spin resonance experiment. The results suggest a metallic and thermal activated hopping like character for the in-plane and c-axis charge transport respectively. The analysis of the resonance for pure graphite gives, within the experimental accuracy, the expected temperature dependence for the in-plane and c-axis resistivities, and an almost temperature independent Pauli paramagnetic susceptibility. The temperature dependence of the linewidth is attributed to the dependence of both the carrier s mobility and the ratio between the transition probability for spin-flip due to spin-orbit coupling and the coulomb scattering. For stage one and seven the resonance parameters reveal a phase transition at 210K and 168K respectively
Doutorado
Física
Doutor em Ciências
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Assis, Alice [UNESP]. "Ressonância paramagnética eletrônica (RPE) aplicada em semicondutores orgânicos." Universidade Estadual Paulista (UNESP), 2012. http://hdl.handle.net/11449/99662.
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assis_ap_me_bauru.pdf: 1776544 bytes, checksum: 48c9cf6c5410b29d4895cea2f725c0da (MD5)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Um importante fator para a vida útil de dispositivos emissores de luz que utilizam compostos organometálicos como material emissor é a compreensão do seu mecanismo de degradação. O principal mecanismo de degradação destes materiais é a dissociação reversível/irreversível entre o átomo metálico central e um de seus ligantes após a excitação da molécula emissora. O complexo de carga formado em decorrência da dissociação irreversível pode ser sensível a campos magnéticos aplicados, através da interação do campo com o elétron desemparelhado. Desta forma, neste trabalho foram avaliados, através de medidas de ressonância paramagnética eletrônica (RPE), os possíveis processos de degradação em sistemas contendo a dispersão de dois compostos organometálicos fac tris(2-fenilpiridina) irídico (ir(ppy)3) e irídio bis(4,6-diflúorfenil)-piridinato-N, C2) picolinato (Flrpic) em diferentes matizes poliméricas como o poliestireno (PS), o poli(9,9-dioctifluoreno-2,7-dil) (PFO) e o polimetilmetacrilato (PMMA). Foi avaliada ainda a influência da molécula doadora de cargas 1,2,4,5-tetracianobenzeno (TCNB) na dispersão Flrpic+PS. Os processos de degradação foram estudados através da análise de diversos parâmetros, como o comportamento do sinal de RPE com a fotoexcitação, processo de relaxação do sinal em diferentes temperaturas e à avaliação do sinal de RPE dos compostos organometálicos puros e nas diferenetes dispersões em matizes poliméticas. Os resultados mostraram que um sinal de RPE relativamento baixo é obtido para o composto Flrpic puro. Entretanto a sua inserção em matrizes poliméricas promoveu um aumento significativo da intensidade do sinal. Dados de absorção e emissão óptica dos compostos evidenciaram que espécies excitadas são inicialmente fotogenadas nos complexos metálicos...
Understanding the degradation mechanism of light emitting devices based on organometallic compounds is the major point to improve their life time. The main mechanism of degradation of these materials is the reversible/irreversible dissociation between the central metallic atom and one of its ligands after the excitation of the emiting molecule. The carge complex formed due to the irreversible dissociation may be sensitive to applied magnetic fields through the field interaction with the unpaired electron. Thus, in this study the possible degradation processes in dispersion systems composed by two organometallic compounds Iridium(III)bis(4,6-fluorephenyl)-pyridiano-N, C2]picolinate (Flrpic) and iridium(III)fac-tris(2-phenylpyridine) (Ir (ppy)3) in different polymer matrices (polystyrene (PS), poly(methylmethacrylate) (PMMA) and poly(9,9-dioctylfluorene) (PFO) were analysed through electron paramagnetic resonance (ERP) technique. The influence of a charge donor molecule 1,2,4,5-tetracyanobenzene (TCNB) in Flrpic+PS dispersion was also examined. The processes of degradation were studied by analysing a variety of parameters such as the behaviour or the EPR signal with the photoexcitation, the process of signal relaxation at different temperatures and the evaluation of the EPR signal of pure organometallic compounds and its dispersion in different polymeric matrices. The results showed that a relatively low EPR signal is obtained for pure Flrpic compound. However its insertion in polymeric matrices caused a significant increase in the signal intensity. The optical absorption and emission data have shown that the excited species are initially photogenerated in metal complexes of those compounds, promoting the subsequent formation of paramagnetic centres, close to Indium atom. The energy levels analysis also suggests an exciton trapping process, which were associated with... (Complete abstract click electronic access below)
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Assis, Andrei Paulo de. "Ressonância paramagnética eletrônica (RPE) aplicada em semicondutores orgânicos /." Bauru, 2012. http://hdl.handle.net/11449/99662.
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Orientador: Carlos Frederico de Oliveira GraeffBanca: Claudio José Magon
Banca: José Humberto Dias da Silva
O Programa de Pós Graduação em Ciência e Tecnologia de Materiais, POSMAT, tem caráter institucional e integra as atividades de pesquisa em materiais em diversos campi
Resumo: Um importante fator para a vida útil de dispositivos emissores de luz que utilizam compostos organometálicos como material emissor é a compreensão do seu mecanismo de degradação. O principal mecanismo de degradação destes materiais é a dissociação reversível/irreversível entre o átomo metálico central e um de seus ligantes após a excitação da molécula emissora. O complexo de carga formado em decorrência da dissociação irreversível pode ser sensível a campos magnéticos aplicados, através da interação do campo com o elétron desemparelhado. Desta forma, neste trabalho foram avaliados, através de medidas de ressonância paramagnética eletrônica (RPE), os possíveis processos de degradação em sistemas contendo a dispersão de dois compostos organometálicos fac tris(2-fenilpiridina) irídico (ir(ppy)3) e irídio bis(4,6-diflúorfenil)-piridinato-N, C2) picolinato (Flrpic) em diferentes matizes poliméricas como o poliestireno (PS), o poli(9,9-dioctifluoreno-2,7-dil) (PFO) e o polimetilmetacrilato (PMMA). Foi avaliada ainda a influência da molécula doadora de cargas 1,2,4,5-tetracianobenzeno (TCNB) na dispersão Flrpic+PS. Os processos de degradação foram estudados através da análise de diversos parâmetros, como o comportamento do sinal de RPE com a fotoexcitação, processo de relaxação do sinal em diferentes temperaturas e à avaliação do sinal de RPE dos compostos organometálicos puros e nas diferenetes dispersões em matizes poliméticas. Os resultados mostraram que um sinal de RPE relativamento baixo é obtido para o composto Flrpic puro. Entretanto a sua inserção em matrizes poliméricas promoveu um aumento significativo da intensidade do sinal. Dados de absorção e emissão óptica dos compostos evidenciaram que espécies excitadas são inicialmente fotogenadas nos complexos metálicos...
Abstract: Understanding the degradation mechanism of light emitting devices based on organometallic compounds is the major point to improve their life time. The main mechanism of degradation of these materials is the reversible/irreversible dissociation between the central metallic atom and one of its ligands after the excitation of the emiting molecule. The carge complex formed due to the irreversible dissociation may be sensitive to applied magnetic fields through the field interaction with the unpaired electron. Thus, in this study the possible degradation processes in dispersion systems composed by two organometallic compounds Iridium(III)bis(4,6-fluorephenyl)-pyridiano-N, C2]picolinate (Flrpic) and iridium(III)fac-tris(2-phenylpyridine) (Ir (ppy)3) in different polymer matrices (polystyrene (PS), poly(methylmethacrylate) (PMMA) and poly(9,9-dioctylfluorene) (PFO) were analysed through electron paramagnetic resonance (ERP) technique. The influence of a charge donor molecule 1,2,4,5-tetracyanobenzene (TCNB) in Flrpic+PS dispersion was also examined. The processes of degradation were studied by analysing a variety of parameters such as the behaviour or the EPR signal with the photoexcitation, the process of signal relaxation at different temperatures and the evaluation of the EPR signal of pure organometallic compounds and its dispersion in different polymeric matrices. The results showed that a relatively low EPR signal is obtained for pure Flrpic compound. However its insertion in polymeric matrices caused a significant increase in the signal intensity. The optical absorption and emission data have shown that the excited species are initially photogenerated in metal complexes of those compounds, promoting the subsequent formation of paramagnetic centres, close to Indium atom. The energy levels analysis also suggests an exciton trapping process, which were associated with...
Mestre
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Zhang, Youwen, Samuel D. Cross, James B. Stanton, Alan D. Marmorstein, Yun Zheng Le, and Lihua Y. Marmorstein. "Early AMD-like defects in the RPE and retinal degeneration in aged mice with RPE-specific deletion of Atg5 or Atg7." MOLECULAR VISION, 2017. http://hdl.handle.net/10150/623963.
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Purpose: To examine the effects of autophagy deficiency induced by RPE-specific deletion of Atg5 or Atg7 in mice as a function of age. Methods: Conditional knockout mice with a floxed allele of Atg5 or Atg7 were crossed with inducible VMD2-rtTA/Cre transgenic mice. VMD2-directed RPE-specific Cre recombinase expression was induced with doxycycline feeding in the resulting mice. Cre-mediated deletion of floxed Atg5 or Atg7 resulted in RPE-specific inactivation of the Atg5 or Atg7 gene. Plastic and thin retinal sections were analyzed with light and electron microscopy for histological changes. Photoreceptor outer segment (POS) thickness in plastic sections was measured using the Adobe Photoshop CS4 extended ruler tool. Autophagic adaptor p62/SQSTM1 and markers for oxidatively damaged lipids, proteins, and DNA were examined with immunofluorescence staining of cryosections. Fluorescence signals were quantified using Image J software. Results: Accumulation of p62/SQSTM1 reflecting autophagy deficiency was observed in the RPE of the Atg5(Delta RPE) and Atg7(Delta RP)E mice. 3-nitrotyrosine, advanced glycation end products (AGEs), and 8-hydroxy-2'-deoxyguanosine (8-OHdG), markers for oxidatively damaged proteins and DNA, were also found to accumulate in the RPE of these mice. We observed retinal degeneration in 35% of the Atg5(Delta RPE) mice and 45% of the Atg7.RPE mice at 8 to 24 months old. Degeneration severity and the number of mice with degeneration increased with age. The mean POS thickness of these mice was 25 mu m at 8-12 months, 15 mu m at 13-18 months, and 3 mu m at 19-24 months, compared to 35 mu m, 30 mu m, and 24 aem in the wildtype mice, respectively. Early age-related macular degeneration (AMD)-like RPE defects were found in all the Atg5(Delta RPE) and Atg7.RPE mice 13 months old or older, including vacuoles, uneven RPE thickness, diminished basal infoldings, RPE hypertrophy/hypotrophy, pigmentary irregularities, and necrosis. The severity of the RPE defects increased with age and in the mice with retinal degeneration. RPE atrophy and choroidal neovascularization (CNV) were occasionally observed in the Atg5(Delta RPE) and Atg7(Delta RPE) mice with advanced age. Conclusions: Autophagy deficiency induced by RPE-specific deletion of Atg5 or Atg7 predisposes but does not necessarily drive the development of AMD-like phenotypes or retinal degeneration.
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Schüle, Georg. "Mechanismen und On-line Dosimetrie bei selektiver RPE Therapie /." Berlin : Dissertation.de, 2003. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=010295155&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
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Moraes, Itamar Jose. "RPE dos íons Cr3+, Er3+ e Mn2+ em Ca3Ga2Ge3O12." Universidade de São Paulo, 1993. http://www.teses.usp.br/teses/disponiveis/54/54132/tde-08122014-162605/.
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O objetivo principal deste trabalho é o estudo por ressonância paramagnética eletrônica das impurezas Cr3+, Er3+ e Mn3+ no monocristal Ca3Ga2Ge3O12 (denominado CGGG) nas freqüências de 1.3, 10 e 34 GHz e nas temperaturas de 4,2K a 300K. O Hamiltoniano de spin para o Cr3+ alojado no sítio octaédrico com simetria C Cr3i é dado por: H = β[g⊥ (HxSx + HySy) + gHzSz] + D (S2z - 1/3 S (S+1). Os parâmetros do Hamiltoniano de spin para o íon Cr3+ em baixas concentrações são: g = 1,9727 ± 0,0003, g⊥ = 1,9617 ± 0,0008 e D = 16,20 ± 0,02GHz para CGGG dopados com o íon Cr3+. Os cristais CGGG, dopados com Er3+ e Cr3+, apresentaram os seguintes parâmetros g = 1,9662 ± 0,0003, g⊥ = 1,9617 ± 0,0008 e D = 15,82 ± 0,02GHz. Os parâmetros do Hamiltoniano de spin efetivo para o íon Er3+ alojado no sítio dodecaédrico e com simetria D2 são: gx = 2,690 ± 0,0005, gy = 4,095 ± 0,005 e gz = 5,082 ± 0,005. Os centros paramagnéticos Mn2+ produzidos em cristais dopados com Cr3+, irradiados com raios X, à temperatura ambiente, apresentam o fator-g isotrópico, g = 2,0066 ± 0,0001 e a constante de interação hiperfina A = 90 Gauss. Medimos, também as dependências das larguras de linhas com a temperatura, nas três bandas e para banda X medimos nas temperaturas de 4,2K até 300KIn this work was studied the Electron Paramagnetic Resonance (RPE) of the impurities Cr3+, Er3+ and Mn3+ in Ca3Ga2Ge3O12 single crystals (Known as CGGG) at frequencies of 1.3, 10 and 34 GHz in the temperatures range 4,2K to 300K. Spin Hamiltonian for the Cr3+ íons, located at octahedric position with symetry Cr3i is given by: H = β[g⊥ (HxSx + HySy) + gHzSz] + D (S2z - 1/3 S (S+1). The relevant parameters for CGGG lightly dopped with Cr3+ as determined from the EPR spectra are: g = 1,9662 ± 0,0003, g⊥ = 1,9617 ± 0,0008 and D = 15,82 ± 0,02GHz. CGGG crystals simultaneously dopped with Er3+ and Cr3+ shown the following parameters: g = 1,9662 ± 0,0003, g⊥ = 1,9617 ± 0,0008 e D = 15,82 ± 0,02GHz. Effective spin Hamiltonian parameters for Er3+ íon, located at dodecahedric position and with symetry D2, are: gx = 2,690 ± 0,0005, gy = 4,095 ± 0,005 e gz = 5,082 ± 0,005. Paramagnetic centers Mn2+ produced in Cr3+ dopped crystals, X-ray irradiated, at room temperature, shown the isotropic g-factor g = 2,0066 ± 0,0001 and the hyperfine interaction constant A = 90 Gauss. Also, was measured the temperature dependence of the line width in the three frequency bands, in the range of liquid nitrogen to room temperature. In the case of the X-band, the measurements were extended to lower temperatures, 4.2K to 300K
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Gao, Jiangyuan. "NLRP3 inflammasome activity in RPE : role in AMD pathogenesis." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/62512.
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Purpose:
Age-related macular degeneration (AMD) is a devastating eye disease causing irreversible vision loss in the elderly. Retinal pigment epithelium (RPE), an important cell type afflicted in AMD, undergoes cell death in the late stages of the disease. Salient factors underlying AMD pathogenesis are aging, drusen components and NLRP3 inflammasome activity. The purpose of this dissertation is to elucidate the molecular interactions among these factors and how they contribute to RPE damage.
Methods:
The effects of aging on drusen components, in particular the membrane attack complex (MAC) and amyloid beta (Aβ) were examined in rats at different age. To determine the role of MAC in inflammasome activation in RPE, aurin tricarboxylic acid complex (ATAC), was administrated to naïve rats. To understand Aβ’s role in inflammasome activation, Aβ intravitreal injections were made into rat eyes in vivo and Vinpocetine was used to ameliorate the inflammatory responses. An in vitro RPE cell culture model was established to further investigate the relationship between inflammasome and X-chromosome linked inhibitor of apoptosis (XIAP). Statistical significance was set at p ≤ 0.05.
Results:
An age-dependent increase in MAC, Aβ, and NF-κB activation was observed in the RPE-choroid in vivo. Blocking MAC formation with ATAC led to a prominent reduction in inflammasome activity (caspase-1 cleavage and cytokine secretion), but not in NF-κB activity. Aβ intravitreal injections triggered inflammasome activation evidenced by enhanced caspase-1 cleavage and IL-1β/IL-18 release, which was suppressed by Vinpocetine mediated NF-κB inhibition. The robust inflammasome activity further led to gasdermin D-mediated activation of the pyroptotic pathway and a significant reduction in XIAP, which in turn enhanced IL-18 secretion.
Conclusion:
Aging is a strong risk factor for AMD, which increases the deposition of MAC and Aβ in the outer retina. The elevated levels of MAC and Aβ are triggers for inflammasome activation. By demonstrating a causal relationship between inflammasome activation and XIAP reduction, this dissertation suggests the precise regulation of XIAP, together with the suppression of MAC and NF-κB, may be crucial for controlling inflammasome activity and hence provides new avenues to prevent AMD.Medicine, Faculty of
Graduate
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Sterle, Jodi A. "Effect of recombinant porcine somatotropin (rpST) on placental and fetal growth in gilts /." free to MU campus, to others for purchase, 1998. http://wwwlib.umi.com/cr/mo/fullcit?p9901288.
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Santana, Ricardo Costa de. "RPE do ion Fe3+ em monocristais e fibras de LiNbO3." Universidade de São Paulo, 1994. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-09042008-084147/.
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O objetivo deste trabalho foi o estudo do íon Fe3+ em monocristais e fibras monocristalinas de LiNbO3, através da técnica espectroscópica da Ressonância Paramagnética Eletrônica (RPE), nas freqüências de 10 e 34GHz, à temperatura ambiente. O Hamiltoniano de Spin para o íon Fe3+ ocupando um sítio de simetria trigonal (C3v) é dado por: H = \'beta\' \'VET.H\' \'VET.g\' \'VET.S\' + \'B20O20+B40O40 . Foram analisadas três amostras de LiNbO3, com diferentes concentrações de Fe3+ e os parâmetros de campo cristalino e fator-g encontrados são: fibra (0.3 mol% de Fe3+) g = 1.9908 \'+OU-\' 0.0002, \'B. SUP. 0 INF. 2\' = 5.4\'+OU-\'0.2x10-2 cm-1 , \'B. SUP. 0 INF. 4\' = -7.7\'+OU-\'1.5x10-5cm-1, monocristal 90 (0.22 mol%) g = 2.0043\'+OU-\'0.0002, \'B. SUP. 0 INF. 2\' = 5.35\'+OU-\'0.25x10-2 cm-1, \'B. SUP. 0 INF. 4\'= - 4.03\'+OU-\'1.4x10-5cm-1, monocristal 99 (0.02 mol%) g = 2.0026\'+OU-\'0.0004, \'B. SUP. 0 INF. 2\' = 5.4\'+OU-\'0.3x10-2 cm-1, \'B. SUP. 0 INF. 4\' = - 8.33\'+OU-\'1.6x10-5cm-1. Foi medida e analisada a dependência angular da largura das linhas nas duas bandas de freqüências. Através de modelos teóricos (Watanabe, Orbach-Das-Sharma, Spinspin, Spin-spin Spin-órbita) calculamos o parâmetro de desdobramento a campo zero, \'B. SUP. 0 INF. 2\', do estado fundamental do íon Fe3+, para determinar qual o sítio que este íon ocupa no LiNbO3.We report EPR measurements of Fe3+ ion in bulk LiNbO3 single crystals and in the form of fibers. Spin Hamiltonian for the Fe3+ ion in a trigonal symmetry (C3v) site is given by: H = \'beta\' \'VET.H\' \'VET.g\' \'VET.S\' + \'B20O20+B40O40. Measurements were performed at room temperature and two frequency bands, 10 and 34GHz, using three samples of LiNbO3 with different concentrations of Fe3+ g-factor and the crystal field parameters were found to be: for fiber (0.3 mol% of Fe3+) g = 1.9908 \'+OU-\' 0.0002, \'B. SUP. 0 INF. 2\' = 5.4\'+OU-\'0.2x10-2 cm-1 , \'B. SUP. 0 INF. 4\' = -7.7\'+OU-\'1.5x10-5cm-1, for the single crystal 90 (0.22 mol%) g = 2.0043\'+OU-\'0.0002, \'B. SUP. 0 INF. 2\' = 5.35\'+OU \'0.25x10-2 cm-1, \'B. SUP. 0 INF. 4\'= - 4.03\'+OU-\'1.4x10-5 cm-1, and for the single crystal 99 (0.02 mol%) g = 2.0026\'+OU-\'0.0004, \'B. SUP. 0 INF. 2\' = 5.4\'+OU-\'0.3x10-2 cm-1, \'B. SUP. 0 INF. 4\' = - 8.33\'+OU-\'1.6x10-5cm-1. The angular dependence of the line width were also measured and compared with theoretical model. To determine the substitutional site of Fe3+ ion in the LiNbO3 lattice, we calculated the zero field splitting parameter \'B. SUP. 0 INF. 2\' of the ground state, using many theoretical models (Watanabe, Orbach-Das-Sharma, Spin-spin, Spin-Spin Spinorbita).
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Michel, Philippe. "Synthèse et étude de matériaux organiques à raie RPE étroite." Paris 11, 1989. http://www.theses.fr/1989PA112013.
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Les sels de radicaux cations de polyaromatiques présentent des propriétés RPE interressantes ainsi le matériau(fluoranthene) 2PF6 possède une largeur de raie RPE de 10 MG. L'intabilité thermique de ces colides constitue un obstacle a leur utilisaton industrielle. Nous avons supposé que l'instabilité des matériaux était due au potentiel d'oxydation trop élevé des substrats utilisés. Nous avons cherché à l'abaisser en substituant les molécules organiques. Cette substitution ayant également pour effet de modifier la dimensionnalité des matériaux nous avons préparé deux pérylènes substitués par une voie de synthèse originale. L'un d'entre eux a conduit à un sel de radical -cation, présentant une faible larguer de raie RPE (16 MG) et une bonne stabilité thermique. Nous avons cherché à l'expliciter les différents facteurs qui seraient responsables, du rétrécissement dela raie. Ainsi nous avons préparé et étudié le sel de radiacl-cation connu de stchiométrie 2:1 du pérylène lui-même et celui du 1,2,7,8-Tetrahydro-CD LM-Dicyclopentaperylene. La comparaison des données structurales à permis de mettre en évidence l'effet de la dimensionnalité sur la largeur de raie. Il semble ainsi possible d'obtenir des matériaux à raies encoire plus étroites en substituant convenablement les substrats adéquatsRadical-cation salts derived from polyaromatic donors exhibit very interesting EPR properties. Thus, the linewidth of the material (fluo19 ranthene) 2PF6 is only 10 mG. However, the high thermal instability of these solids has so far precluded industrial applications. Our goal was to obtain stable materials with a narrow EPR line. We assumed that the high oxydation potentials of the substrates was one of the reasons of the instability. We have tried to lower these potentials by an adequate substitution of the aromatic molecules, the effect of this substitution being also to modify dimensionnality of the materials, a factor which would predictibly affect the linewidth. We have prepared two substituted perylenes, using an original synthesis. One of the them, the 3,4,9,10-tetramethylperylene, led to a radicalcation salt, with a 2:1 stoechiometry. The linewidth of this material is 16 mG, its thermal stability is very good up to 80°C. We then attempted to investigate the factors which might be responsible of the narrowing of the line, in this series deriving from perylene. Therefore, we prepared and studied the 2:1 radical-cation salts of perylene itself. We prepared also the 2:1 salt deriving from 1,2,7,8 -tetrahydro [cd;1m]dicyclopentaperylene, which had already been described. The comparison of the structural data allowed us to show unambiguously the beneficial effect of the dimensionnality on the linewidth. It seems possible, adopting the same approach we used for perylene, to obtain materials with still narrower EPR lines by adequatly substituting the suitable substraces. The communication of the contents of this thesis is submitted to the authorization of the Thomson-Sintra ASM company
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Barbosa-Sabanero, Karla Y. "Dedifferentiation and transdifferentiation: a study of the RPE cell identity." Miami University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=miami1468660645.
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Lu, Tianlin. "Studies on the Mechanism behind Retinal Pigment Epithelium (RPE) Reprogramming." Miami University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=miami1575301308695243.
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Gambarelli, Serge. "Etude des proprietes magnetiques et des spectres rpe de biradicaux nitroxydes." Paris 6, 1996. http://www.theses.fr/1996PA066560.
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Cette these traite des proprietes magnetiques variees de biradicaux nitroxydes. Nous etudions tout d'abord en phase solide et en solution trois biradicaux derives du metaxylylene. L'importance de la conformation des molecules sur leur etat fondamental est mis en evidence. Puis, a partir des donnees de la litterature, la nature de la transition de phase magnetique du dupeyredioxyle est discute. Un cryostat est fabrique avec lequel sont faites des mesures de rpe en bande x et a 1,4 k sur des monocristaux orientes. Les spectres obtenus montrent que ce compose est un antiferromagnetique fortement anisotrope. Enfin, deux biradicaux sont etudies par rpe haut champ. Les conformations de ces especes sont determines en solution
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Crouigneau, Pierre. "Etudes spectroscopiques (electroréflexion uv-visible, RPE) et electrochimiques de dérivés viologènes." Poitiers, 1989. http://www.theses.fr/1989POIT2003.
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L'examen critique des nombreux travaux consacres a la conversion de l'energie solaire par les systemes photosynthetiques artificiels montre que le comportement interfacial des relais d'electrons (viologenes) est relativement mal connu. Deux familles de viologenes comprenant respectivement un ou deux groupement bipyridinium ont ete etudiees a l'aide de techniques spectroscopiques (resonance paramagnetique electronique et spectroscopie uv-visible d'electroreflexion) et electrochimiques (voltammetrie) associees. Les radicaux formes in situ a l'interface solide (metal, semi-conducteur) - solution aqueuse ont pu etre detectes et leurs proprietes (taux de recouvrement des electrodes, duree de vie des especes formees, aptitude a la dimerisation,. . . ) elucidees. Ces resultats permettent de selectionner les relais d'electrons les plus performants et de determiner les concentrations conduisant aux meilleurs rendements de conversion de l'energie lumineuse
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Theurel, Laurence. "Synthèse et caractérisation de radicaux organiques stables pour la magnétométrie RPE." Grenoble 1, 1993. http://www.theses.fr/1993GRE10199.
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Notre travail a consiste a synthetiser et caracteriser de nouveaux materiaux radicalaires de trois familles differentes (neutres, cations et anions), pour les applications de la magnetometrie par resonance paramagnetique electronique (rpe). Trois nouvelles phtalocyanines de lithium octa-substituees ont ete preparees. Les etudes rpe ont montre que ces composes ne possedent pas d'avenir pour nos applications. Nous avons prepare deux nouveaux radicaux cations du perylene avec comme anion associe, teof#5# et ((teof#5)h)#. Les bonnes caracteristiques de ce dernier font de lui un candidat a fort potentiel pour la magnetometrie. Plusieurs radicaux tcnq ont ete synthetises et caracterises par rpe. De ces etudes, deux materiaux se sont reveles particulierement interessants pour les applications haute temperature. Une nouvelle classification des radicaux est proposee: les radicaux avec effet d'oxygene et les radicaux avec effet de recuit
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Coburn, Glen Andrew. "Reconstitution of the decay of the rpsT mRNA, encoding ribosomal protein S20, with purified enzymes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ34545.pdf.
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Eversmeyer, Lauren Michelle. "TWO-COMPONENT REGULATORY SYSTEM IN PSEUDOMONAS AERUGINOSA: COMPLEMENTING RPEB IN WILD-TYPE AND NEGATIVE MUTANTS." Thesis, The University of Arizona, 2009. http://hdl.handle.net/10150/192321.
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Mostajeran, Zahra [Verfasser]. "The influence of vimentin on actin dynamics and force generation in RPE1 cells / Zahra Mostajeran." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2021. http://d-nb.info/1237268761/34.
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Cordes, Magdalena [Verfasser]. "Regulation der Oberflächenexpression von L-Typ-Ca2+-Kanälen im RPE / Magdalena Cordes." Berlin : Freie Universität Berlin, 2019. http://d-nb.info/1196803838/34.
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Law, A. L. "The role of annexin 2 in RPE phagocytosis of photoreceptor outer segments." Thesis, University College London (University of London), 2009. http://discovery.ucl.ac.uk/18708/.
Full textAbstract:
The Retinal Pigmented Epithelium (RPE) has many functions, one of which is the phagocytosis of shed photoreceptor outer segments (POS). This process is vital to the maintenance of both the RPE and photoreceptors. Outer segment shedding and internalisation are under circadian regulation, such that shedding is followed by a burst of phagocytosis at the onset of light. Annexin 2 is well placed to have a role in this process. Its direct involvement in actin dynamics and association to vesicle membranes during endocytosis may be significant in RPE outer segment phagocytosis, as this process requires extensive re-organisation of actin and re-distribution of membrane on the apical processes of the RPE. This thesis examines cell differentiation in two RPE cell lines and in primary porcine RPE cells, in order to evaluate the best system for conducting phagocytosis experiments. In vitro experiments provided evidence that annexin 2 localises to the phagocytic cup during POS internalisation but dissociates once internalisation is complete. Following knock down of annexin 2, phagocytosis was shown to decrease. Furthermore annexin 2 was shown to be phosphorylated during phagocytosis. We also found that c-Src is phosphorylated alongside annexin 2 and therefore may phosphorylate annexin 2, which contains a c-Src phosphorylation site. To investigate the circadian aspects of POS phagocytosis by the RPE, apical and basal phagosomes were quantified in the RPE from annexin 2 knock out and wild type eyes, harvested before and after light onset. Phagosomes from eyes harvested one hour after light onset were also mapped relative to Bruch’s membrane. The annexin 2 knock out animals lack the characteristic burst of phagocytosis one hour after light onset exhibited in wild type animals. Phagosomes were also retarded in the apical processes one hour after light onset, at the peak of phagocytosis, when they are normally internalised into the cell body for processing and degradation. Lysates from wild type eyes showed that annexin 2 is phosphorylated before light onset along with c-Src and FAK, key molecules in the RPE phagocytic machinery. Importantly, the absence of annexin 2 in knock out eyes delayed phosphorylation of c-Src and FAK. This delay in phosphorylation of two key RPE phagocytosis molecules may account for the delay in ingestion of outer segments into the cell body and the accumulation of phagosomes in the apical processes observed in the knock out animals. In conclusion, work in this thesis has demonstrated that annexin 2 is required for efficient RPE internalisation of rod outer segments both in vitro and in vivo. Annexin 2 is required for the timely phosphorylation of FAK and c-Src, which may account for the delay in POS internalisation observed in the annexin 2 knock out mice.
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Bakker, Linda Margaretha. "Peroxidized docosahexaenoic acid causes RPE dysfunction : implications for retinal ageing and AMD." Thesis, Cardiff University, 2008. http://orca.cf.ac.uk/54734/.
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The aim of this study was to gain important insights into the effects of peroxidized docosahexaenoic acid (pDHA) on the retinal pigment epithelium (RPE), and whether its effects can cause RPE cell dysfunction in a way similar to that observed in retinal ageing and the pathogenesis of age-related macular degeneration (AMD). Initially, the time-course of in vitro peroxidation of DHA was monitored, culminating in formation of products able to absorb light above 400 nm. Cultured RPE cells were then exposed to this pDHA, which was shown to be toxic, both in dark and light-exposed conditions. Various cell viability assays were carried out indicating RPE cell death after exposure to pDHA is likely to occur by apoptosis. The effects of pDHA were reduced in the presence of various agents - a-tocopherol, glutathione, N-acetylcysteine, and phosphatidylethanolamine (PE). Measurements of singlet oxygen, transient and superoxide production were carried out to determine the photosensitizing properties of pDHA. The ability of PE to reduce the production of these species was investigated but it was shown to have no effect on their yield, although singlet oxygen lifetime was reduced. Finally, lysosomal enzyme activity, lysosomal integrity and accumulation of fluorescent and undegraded material were monitored after exposure to pDHA, demonstrating that pDHA was able to disrupt the ability of the RPE to fully degrade phagocytosed material. In summary, pDHA is able to affect RPE cell viability directly when exposed extracellularly, and can also affect essential normal functions of the RPE intracellularly. In conjunction with published findings that pDHA is present in the retina - both within and around the RPE - the data presented here support the theory that pDHA can play an important role in causing RPE dysfunction, resulting in a loss of the protective role these cells play for photoreceptors, as occurs in retinal ageing and AMD.
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Armstrong, Ian. "A study of the transport characteristics of mammalian retinal pigment epithelium (RPE)." Thesis, Cardiff University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.276870.
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Ouajahat, Filali Aziz. "Evaluation de la photoréactivité des quinolones antibactériennes par photo-CIDNP et RPE." Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb376085778.
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Brasil, Filho Nilson. "Ressonância magnética eletrônica (RPE) e nuclear (RMN) em compostos e hidretos metálicos." [s.n.], 1985. http://repositorio.unicamp.br/jspui/handle/REPOSIP/278166.
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Orientador: Jose Suassuna FilhoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin
Made available in DSpace on 2018-07-17T03:32:32Z (GMT). No. of bitstreams: 1 BrasilFilho_Nilson_M.pdf: 2125274 bytes, checksum: fd2f77e8149f9df15d3ca21677423de5 (MD5) Previous issue date: 1985
Resumo: Foram realizadas medidas de RMN pulsadas nos hidretos metálicos ZrCr2Hx (x = 2, 3 e 4) e ZrV2Hy (y = 2, 3, 4 e 5) no intervalo de temperatura entre 180K e 400K. Nosso objetivo foi investigar os mecanismos de relaxação nesses hidretos através de medidas dos tempos de relaxação spin-rede (T1) e spin-spin (T2) para o hidrogênio, e obter informações com respeito aos mecanismos de difusão do hidrogênio na rede metálica. Foram obtidas as energias de ativação, as freqüências de salto e a constante Ck, relacionada com a relaxação spin-elétron de condução, para o hidrogênio nos hidretos acima citados. Nossos resultados foram analisados à luz das teorias de relaxação modulada por interação dipolar (modelos de BPP e de Torrey) e da relaxação tipo Korringa (devida aos elétrons de condução) em sistemas metálicos. Na segunda parte desta tese, foram medidos o deslocamento do fator-g e a razão de Korringa nas linhas de RPE dos íons Gd3+, Nd3+ e Er3+ diluídos em compostos intermetálicos AB3 (A = La, Ce, Y, Sc, Th, Zr; B = Rh, Ir, Pt) de estrutura tipo AuCu3. Os resultados de RPE nestas séries de compostos foram analisados em termos do modelo de multibandas em metais, proposto anteriormente por Barberis e outros (1979) para explicar o comportamento dos parâmetros de Ressonância em compostos intermetálicos do tipo fase de Laves AB2
Abstract: Proton pulsed Nuclear Magnetic Resonance measurements were performed on the metallic hydridesZrCr2Hx (x = 2, 3, 4) and ZrV2Hy (y = 2, 3, 4, 5) as a function of temperature between 180 and 400 K. The ultimate aim was the investigation of the relaxation mechanisms in these systems by means of the measurement of both the proton (1H) spin-lattice (T1) and spin-spin (T2) relaxation times and to use these data to obtain information about the diffusive motion of the hydrogen atoms. The diffusional activation energies, the jump frequencies and the Korringa constant, Ck, related with the conduction electron contribution to the 1H relaxation were determined for the above hydrides as a function of hydrogen concentration. Our results were analyzed in terms of the relaxation models described by Bloembergen, Purcell and Pound (BPP models) and by Torrey. The Korringa type relaxation due to conduction electrons in metallic systems was also used to interpret the experimental results. We also present the Electron Paramagnetic Resonance (EPR) study of Gd3+, Nd3+ and Er3+ ions a impurities in several AB3 intermetallic compounds were A = La, Ce, Y, Sc, Th, Zr and B = Rh, Ir, Pt. The results were analyzed in terms of the multband model previously suggested to explain in the behavior of the resonance parameter in AB2 Laves Phase compound
Mestrado
Física
Mestre em Física
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Piccinato, Marilene Turini. "Caracterização de vanadila (VO2+) em petróleo através de ressonância paramagnética eletrônica (RPE)." Universidade Estadual de Londrina. Centro de Ciências Exatas. Programa de Pós-Graduação em Física, 2005. http://www.bibliotecadigital.uel.br/document/?code=vtls000114955.
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Foram analisadas, através da técnica de Ressonância Paramagnética Eletrônica (RPE), amostras de petróleo provenientes dos seguintes países: Argentina (AR), Arábia Saudita (AS), Colômbia (CO), Kuwait (KW), Venezuela (VE) e Brasil. Neste último nos campos
petrolíferos da Bahia (BA), Bacia de Campos (BC), Marlim (B1), Albacora (B2), Cabiúnas (B3), Espadarte (B4), Roncador (B5) e mais três misturas (M1, M2 e M3) utilizadas no Brasil para a produção de derivados. Dentre as espécies paramagnéticas detectadas nos óleos, foram calculados os parâmetros da Hamiltoniana de Spin da vanadila (VO2+): o fator espectroscópico anisotrópico ou fator g e o desdobramento hiperfino. Os valores do chemical shift {Ag0 = (2,003 = g0) x 10 3} 0 0 10 0023 , 2 × - = . g g }, correspondente ao sinal de VO2+ nos óleos da AR, SA, CO, KW, VE, BC, M1, M2, B1, B2, B4 e B5 que estão entre 0 , 25 0 = .g e 0 , 26 0 = .g , sugerem complexos de vanádio do tipo: VO(N2OS), VO(S2O2) ou VO(N3O), enquanto que nos óleos M3 e B3 o valor de 0 27 0 , g = . é característico de complexos de vanádio do tipo VO(S2O2) ou VO(NSO2). As variações nos valores determinados para o parâmetro de interação hiperfina ( 0 A ) do sinal de RPE de VO2+ nos óleos foram muito pequenas (~1%), caracterizando a semelhança da vizinhança química que se encontra o íon paramagnético VO2+. A intensidade relativa do sinal de VO2+ revelou que, o petróleo da Bahia (BA) possui a menor quantidade de íons VO2+, enquanto que o petróleo da Argentina (AR) possui ~87,3 vezes mais íons vanadila.The samples were analyzed, by the technique of Electron Paramagnetic Resonance (EPR), starting from petroleum of the following countries: Argentina (AR), Saudi Arabia (SA), Colombia (CO), Kuwait (KW), Venezuela (VE) and Brazil. In this last one in the oil fields of Bahia (BA), Basin of Campos (BC), Marlim (B1), Albacora (B2), Cabiúnas (B3), Espadarte (B4), Roncador (B5) and three mixtures (M1, M2 and M3) be used in Brazil for the production of oil derivatives. Amongst paramagnetic species detected in oils by EPR were calculated Spin Hamiltonian parameters of vanadyl (VO2+): anisotropy spectroscopic factor or g-factor and unfolding hyperfine. The value of chemical shift {Ag0 = (2,003 = g0) x 10 3}0 0 10 g 0023 . 2 g × - = . } corresponding to the VO2+ signal in the oils AR, SA, CO, KW, VE, BC, M1, M2, B1, B2, B4 and B5 that are between 0 25 0 . g = . and 0 26 0 . g = . , suggests vanadium complexes of the type VO(N2OS), VO(S2O2) or VO(N3O), while which in M3 and B3 oils, the value of 0 . 27 0 = .g it is characteristic of vanadium complexes of type VO(S2O2) or VO(NSO2). The variations found in the hyperfine interaction parameter ( 0 A ) of the VO2+ EPR signal in petroleum were small (~1%), demonstrating the similarity in the chemical environment of the paramagnetic ion VO2+. The relative intensity of the VO2+ signal revealed that Bahia's Petroleum (BA) has the smallest quantity of ions VO2+, while Argentina's Petroleum (AR) has ~87.3 larger ions vanadyl.
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Nogueira, Roberto Alves. "Aquisição de dados em experiências de RPE usando minicomputador de tempo real." Universidade Federal de Minas Gerais, 1990. http://hdl.handle.net/1843/BUOS-97WF8D.
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In this work we developed two real-time acquisition computer systems, for data acquisition in Electron Paramagnetic Ressonance Experiments. In both, a high degree of freedom was kept in the measuring instruments configuration and progrtamming, whiti the sim of making easy a future reassignment to other experimental technics to be installed in the laboratory. One of the systems is an improves version of the so called Passive Monitoribs System and was built in such a way that it can be used in conjunction with the normal operation mode of the spectrometer. The other system incorporates, in addition to the data acquisition facilities, an step motor based gear to drive the sweep of the magnetic field. Furthermore, a large program was also developed to facilitate the processing of the spectra and their transportation to other computers.
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Goze-Bac, Christophe. "Contribution à l'étude du fullerène C60 et dérivés : études RMN et RPE." Montpellier 2, 1996. http://www.theses.fr/1996MON20047.
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Le but poursuivi dans ce travail est l'analyse des proprietes physiques de certains derives du fullerene c60. A l'aide des techniques rmn et rpe, nous avons etudie les composes axc60 avec a=k, rb, cs et x=1, 3, 4 et 6 dont nous avons assure la preparation. Nous avons etudie aussi les polymeres orthorombique 1d et rhomboedrique 2d obtenus sous haute pression et temperature. Nos resultats ont apporte des elements essentiels a la comprehension de ces nouveaux materiaux. Nous avons apporte la confirmation de la liaison de cycloaddition entre molecule c60 dans les phases polymeres. Nous avons determine l'origine de la resonance inattendue t' dans le spectre rmn de l'alcalin du compose rb3c60 et propose un modele base sur la diffusion de sites tetraedriques vacants. Nous avons explique le caractere isolant de la phase 4 a l'aide d'un modele base sur l'effet jahn-teller moleculaire. Dans la phase saturee, nous avons confirme l'ordre orientationnel des molecules de c60 et la presence de carbones inequivalents prevus par les etudes structurales
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Ouajahat, Filali Aziz. "Evaluation de la photoréactivité des quinolones antibactériennes par photo-CIDNP et RPE." Lille 1, 1987. http://www.theses.fr/1987LIL10034.
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FEAUGAS, VALERIE. "Caracterisation des facteurs influant sur l'evolution du signal rpe de l'alanine irradiee." Paris 11, 1999. http://www.theses.fr/1999PA112310.
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La dosimetrie par resonance paramagnetique electronique (rpe) de l'alanine est basee sur la mesure du signal rpe des radicaux libres, induits dans l'alanine par irradiation. L'objectif de cette these etait de caracteriser les facteurs influant sur l'evolution de l'amplitude du signal rpe de l'alanine irradiee afin de limiter l'incertitude sur la determination de la dose absorbee. La premiere etape de ce travail a ete le choix de l'isomere d'alanine et de la forme physique du dosimetre. Une etude bibliographique completee par des experiences sur la reponse des isomeres de l'alanine a la dose et sur sa stabilite dans le temps, nous a conduit a choisir comme dosimetre la l--alanine sous forme pulverulente. L'influence des parametres de reglage du spectrometre sur les caracteristiques du spectre rpe a ensuite ete etudiee. Ceci nous a permis d'optimiser les conditions d'enregistrement des spectres rpe. L'anisotropie angulaire du signal rpe de l'alanine limitant la reproductibilite des mesures, un protocole experimental a ete defini de facon a pallier cet effet. La repetabilite des mesures a ete amelioree en modifiant le spectrometre et en utilisant une reference interne constituee de monocristaux de cuso 4. 5h 2o. L'amplitude du signal rpe etant sensible a la temperature de lecture, une methode de normalisation des resultats a 20\c a ete mise au point. Nous nous sommes interesses a l'influence d'un parametre d'irradiation et de parametres environnementaux sur l'amplitude du signal rpe de l'alanine irradiee. Nous avons montre que l'amplitude augmente avec la temperature d'irradiation. D'autre part, l'amplitude et sa stabilite au cours du temps sont fortement influencees par la teneur en eau des echantillons. Une forte teneur en eau a un effet nefaste mais en partie reversible sur l'amplitude du signal. L'exposition des dosimetres a la lumiere a egalement pour consequence la diminution de l'amplitude du signal. Par contre, l'oxygene n'influence pas le spectre rpe de l'alanine. Nous avons remarque que l'amplitude du signal rpe d'echantillons stockes en dessicateur avant et apres irradiation augmente d'environ 5% dans la dizaine de jours suivant l'irradiation. Ce phenomene est tres vraisemblablement lie a la poursuite de reactions radicalaires dans l'alanine apres irradiation.
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Robert, Jérôme, and J. J. ANDRE. "Magnetisme des fullerenes intercales : etude par rpe en ondes continue et pulsee." Université Louis Pasteur (Strasbourg) (1971-2008), 1995. http://www.theses.fr/1995STR13151.
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Le but de cette these est l'etude par resonance paramagnetique electronique (rpe) en onde continue et pulsee des composes d'intercalation du fullerene. Dans l'etat normal, la susceptibilite rpe des composes supraconducteurs k3c60 et rb3c60 permet de calculer la densite d'etats au niveau fermi. L'etude de sa variation thermique, associee a la contraction thermique du reseau permet de determiner certains parametres de l'etat supraconducteur dans le cadre de la theorie bcs, comme l'energie caracteristique des phonons, le couplage electron-phonon et la repulsion coulombienne. L'absence des composes k1c60 et rb1c60 dans le premier diagramme de phase est du a leur detection difficile sur les cliches de diffraction des rayons x et a leur instabilite a temperature ambiante. Suivant le traitement thermique, ils se presentent sous trois phases: une phase stable cubique faces centrees haute temperature, une phase polymere orthorhombique (o. P) stable avec le rubidium et metastable avec le potassium en dessous de 350 kelvin et une phase metastable dimere quasi-orthorhombique (o. D) obtenue par trempe de la phase cfc. Chaque phase presente ses propres caracteristiques rpe, ce qui nous permet de circonscrire les regions de stabilite thermique et d'identifier les transformations de phase. Une etude cinetique en fonction de la temperature quantifie l'energie impliquee dans ces transformations de phases. Les experiences de rpe a impulsions confirment le caractere metallique du polymere rb1c60. Enfin, nous interpretons la transition metal-isolant que subit ce compose a basse temperature. Au dela des proprietes isolantes commune des composes k4c60, na2c60 et na9. 8c60. Nous constatons que la variation en fonction de la temperature de la susceptibilite rpe traduit un equilibre singulet fondamental-triplet, dont l'ecart est lui-meme variable avec la temperature pour les deux premiers composes. Le role des modes de phonons intramoleculaires est invoque pour expliquer ce phenomene
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Van, Wichelen Koen. "Etude d'un magnétomètre vectoriel différentiel RPE pour application en puits de forage." Université Joseph Fourier (Grenoble), 1995. http://www.theses.fr/1995GRE10244.
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Un magnetometre rpe pour application en puits de forage a ete etudie. La mesure est de type vectoriel et differentiel. Grace aux developpements recents concernant les materiaux radicalaires pour la magnetometrie rpe, la technologie choisie offre des perspectives par rapport a l'etat de l'art (technologie flux-gate) pour un fonctionnement jusqu'a des temperatures de 200c environ. Un prototype d'outil de diagraphie operationnel a frequence de resonance de 70 mhz a ete developpe pour valider l'architecture du magnetometre. Des mesures avec cet outil de diagraphie ont ete effectuees dans quelques puits de forage afin de valider sa mise en uvre (evaluation des performances en milieu reel d'application, epreuve de reproductibilite). Les performances du magnetometre rpe sont analysees aussi par comparaison avec un instrument vectoriel et differentiel utilisant la technolotie flux-gate
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Lane, Brandon. "Otx but not Mitf transcription factors are required for zebrafish RPE development." VCU Scholars Compass, 2012. http://scholarscompass.vcu.edu/etd/2839.
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Mitf and Otx transcription factors have been identified as essential to the development of the retinal pigmented epithelium (RPE), but the relationship between these factors and their specific role in the RPE developmental pathway have not been clearly defined. The role of the two Mitf transcription factors (Mitfa and Mitfb) and two Otx transcription factors (Otx1a and Otx2) in zebrafish RPE development was explored in these experiments. The loss of Mitf activity in mitfa, mitfb, or double mitf null mutant fish lines had no effect on RPE pigmentation or development. The loss of Otx2 activity through morpholino knockdown produced a RPE deficient phenotype in a small percentage of embryos, while the additional knockdown of Otx1a caused widespread and severe RPE developmental abnormalities. Analysis of ocular sections revealed that the retinal layers remain unaffected in mitf mutants, as well as in most RPE-deficient otx morphants. Mitf and Otx combined loss of function experiments suggest that Mitfa and Mitfb may still play a role in zebrafish RPE development. Expression analysis through in situ hybridization has demonstrated that Otx transcription factors are necessary for the proper expression of mitfa and mitfb while Mitf transcriptions factors are not required for the expression of otx genes. The transcriptional regulation of Mitf by Otx transcription factors may explain why only Otx transcription factors are necessary for zebrafish RPE development despite the somewhat overlapping functions of Mitf and Otx transcription factors.
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Spencer, Samantha A. "The Role of tfec in Zebrafish Neural Crest Cell and RPE Development." VCU Scholars Compass, 2015. http://scholarscompass.vcu.edu/etd/3754.
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Zebrafish (Danio rerio) show a unique pigmentation pattern comprised of three pigment cell types: melanophores, iridophores and xanthophores. Other pigmented cells include the retinal pigmented epithelium (rpe) which absorbs excess light in the eye and maintain the extracellular environment around the photoreceptors. While previous mutations in mitfa showed a role in regulating trunk melanophores, the rpe was not affected. TALENs and CRISPR-Cas9 systems were used to generate mutant zebrafish for tfec, a transcription factor expressed in both neural crest and rpe. Embryos with tfec mutations showed a loss of iridophore pigmentation, and delays in the pigmentation of xanthophores and rpe, showing positive regulation of multiple pigment cells. Double mutants for tfec and mitfa displayed greater losses of iridophore, xanthophore and rpe pigmentation with noncircular globes, suggesting cooperative roles for these transcription factors.
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Ali, Afaf Mubarak Mohamed. "Accounting for performance : case studies of relative performance evaluation in Egypt and England." Thesis, Sheffield Hallam University, 2000. http://shura.shu.ac.uk/19241/.
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Relative Performance Evaluation "RPE" is a performance evaluation and reward scheme which have been receiving a growing attention from academic and professionals (Holmstrom 1982, Frederickson 1992, Conyon and Gregg 1994, and Defond & Park 1999). Under RPE rewards for managers and executives are set upon their performance compared to that of their peers. Holmstrom (1982) introduced the basic model of RPE founded on agent-principal assumptions. In that model, the peers' performance was seen to provide information about the agent's unobservable effort. Fredrickson (1992) suggested that RPE could satisfy economic and psychological needs of employee. In this study, an attempt is made to depart from the universal agency perspective and to adopt a contingent framework. The research arguments were developed from an identification of the discrepancies and gaps in the literature of RPE, overlooked complications and issues in the UK practice, relating the debate about RPE to the wider accounting literature of performance measurements and evaluation (Emmanuel et.al. 1990, Kaplan & Atkinson 1998). The aim of this research was to explore the content and context of RPE therefore, the arguments focused on: whether RPE is motivating, the impacts of difficulty of peer group, non financial measures, market measures and varying the form of the rewards on RPE. Case study approach was adopted to examine the research arguments. Data were collected from three companies in Egypt and one company in England. Access was partially accidental but turned to provide four different cases. Three cases were developed in Egypt including: Trade (a public company), Dairy (private company) and Steel (joint venture) and the English company was United Utilities (private company). Data were collected by questionnaire, interviews and other documentary sources of the companies. The research findings suggest associations between RPE and target's difficulty, using non financial but not varying rewards. Competition and type of ownership and the organisational culture were influential on RPE.
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LESAGE, PASCALE. "Regulation de l'expression genetique au niveau de la traduction dans l'operon infc-rpmi-rplt chez escherichia coli." Paris 11, 1991. http://www.theses.fr/1991PA112192.
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Chez e. Coli, l'operon infc code pour le facteur de demarrage de la traduction if3 (infc) et les proteines ribosomiques l35 (rpmi) et l20 (rplt). Les genes rpmi et rplt sont generalement co-transcrits avec infc. Dans moins de 3% des cas, ils sont exprimes sans infc a partir d'un promoteur interne a infc. Un exces de l20 reprime l'expression de rpmi et rplt, a une etape post-transcriptionnelle. Nous avons identifie les regions essentielles au controle dans les transcrits synthetises a partir du promoteur interne a infc. Elles s'etendent sur 400 nucleotides en amont de rpmi et sont interrompues par deux regions qui ne sont pas impliquees dans le controle. Deux sequences essentielles a la repression par l20 situees dans infc sont separees par 120 nucleotides. La sequence shine-dalgarno de rpmi appartient aussi a l'operateur traductionnel. Dans les transcrits majoritaires ou infc est traduit, l'operateur traductionnel est aussi situe dans infc. C'est la premiere fois qu'un operateur traductionnel est caracterise dans une phase ouverte de lecture. Nous avons prouve que la mauvaise traduction d'infc facilite le controle par l20: si la traduction d'infc augmente, la traduction de rpmi et rplt est moins reprimee par l20. La presence de l'operateur traductionnel de rpmi et rplt dans la phase ouverte de lecture de infc permet donc, de coordonner l'expression de ces trois genes qui participent tous a la traduction. L'expression de rpmi et rplt est couplee. Une mutation dans la sequence shine-dalgarno de rpmi provoque en effet une diminution de la traduction de rpmi et de rplt. Par consequent la surproduction de l20 doit reprimer directement la traduction de rpmi et indirectement par couplage traductionnel celle de rplt. Par des deletions, nous avons localise dans rpmi, une region essentielle au couplage, 140 nucleotides en amont de rplt. Sa suppression rend la traduction de rplt independante de celle de rpmi. Cett
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Yu, Jie. "Classification of Genotype and Age of Eyes Using RPE Cell Size and Shape." Digital Archive @ GSU, 2012. http://digitalarchive.gsu.edu/math_theses/118.
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Retinal pigment epithelium (RPE) is a principal site of pathogenesis in age-related macular de-generation (AMD). AMD is a main source of vision loss even blindness in the elderly and there is no effective treatment right now. Our aim is to describe the relationship between the morphology of RPE cells and the age and genotype of the eyes. We use principal component analysis (PCA) or functional principal component method (FPCA), support vector machine (SVM), and random forest (RF) methods to analyze the morphological data of RPE cells in mouse eyes to classify their age and genotype. Our analyses show that amongst all morphometric measures of RPE cells, cell shape measurements (eccentricity and solidity) are good for classification. But combination of cell shape and size (perimeter) provide best classification.
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McFarlane, S. "An investigation of the effect of advanced glycation on age-related RPE dysfunction." Thesis, Queen's University Belfast, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268450.
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Chevalier, Alain. "Contribution à l'étude par spectroscopie Mössbauer et RPE de la stabilité de l'hémoglobine." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb376126926.
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Graffunder, Corinne Meltzer Weiner Bryan J. "Strengthening the prevention support system in CDC's Rape Prevention and Education RPE program." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2008. http://dc.lib.unc.edu/u?/etd,2093.
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Thesis (DrPH)--University of North Carolina at Chapel Hill, 2008.Title from electronic title page (viewed Feb. 17, 2009). "... in partial fulfillment of the requirements for the degree of Doctor of Public Health in the Department of Public Health." Discipline: Public Health; Department/School: Public Health.
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CATTANI, MARTA M. "Estudo por ressonancia paramagnetica eletronica (RPE) em graos e farinacios irradiados com sup60Co." reponame:Repositório Institucional do IPEN, 1995. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10427.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Clément, Jean-Louis. "Synthèse et études RPE dans la série des pyrrolines n-oxyde b-phosphorées." Aix-Marseille 3, 1998. http://www.theses.fr/1998AIX30096.
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La 2-diethylphosphono-2-methyl-3,4-dihydro-2h-pyrrole 1-oxyde (depmpo) est une nitrone -phosphorylee interessante pour le piegeage de radicaux (spin trapping) comme le radical superoxyde. La premiere partie de ce travail est consacree a la preparation d'une nouvelle serie de nitrones -phosphorylees analogues de la depmpo. Nous avons synthetise la 2-diethylphosphono-2-( 2h 3-methyl)-3- 2h 2,4- 2h 2-dihydro-2h-pyrrole 1-oxyde (depmpo d 7), la 2-diethylphosphono-2-( 2h 3-methyl)-3- 2h 2,4-dihydro-2h-pyrrole 1-oxyde (depmpo d 5), la 2-diethylphosphono-2-methyl-3,4- 2h 2-dihydro-2h-pyrrole 1-oxyde (depmpo d 2) une serie de nitrones deuteriees. Nous avons synthetise la 2-di(2,2,2-trifluoroethyl)phosphono-2-methyl-3,4-dihydro-2h-pyrrole 1-oxyde (depmpo f 6), la 2-dibenzylphosphoryl-2-methyl-3,4-dihydro-2h-pyrrole 1-oxyde (dbzpmpo), la 2-phosphono-2-methyl-3,4-dihydro-2h-pyrrole 1-oxyde (dhpmpo) une serie de nitrones avec des groupes phosphores varies. Nous avons synthetise la 2-diethylphosphono-3-hydromethyl-2-methyl-3,4-dihydro-2h-pyrrole 1-oxyde (4hm depmpo) une nitrone avec une fonction hydroxymethyle en position 3. Nous avons modifie la lipophilie des nitrones en modifiant la nature des substituants autour de l'atome de phosphore en preparant la 2-diphenylphosphono-2-methyl-3,4-dihydro-2h-pyrrole 1-oxyde (dppmpo), la 2-dibenzylphosphono-2-methyl-3,4-dihydro-2h-pyrrole 1-oxyde (dbpmpo), la 2-didecylphosphono-2-methyl-3,4-dihydro-2h-pyrrole 1-oxyde (ddpmpo) et la 2-dioleylphosphono -2-methyl-3,4-dihydro-2h-pyrrole 1-oxyde (dopmpo). Dans le cadre general de l'etude des conformations des adduits de spin issus de la depmpo nous avons synthetise la 2-diethylphosphono-2-( 1 3c-methyl)-3,4-dihydro-2h-pyrrole 1-oxyde (depmpo 1 3c) une nitrone dont le methyle en position 2 est marque par un carbone 13. Dans la deuxieme partie de ce travail nous avons etudie le piegeage de divers radicaux libres pour chacune de ces nouvelles nitrones. Les spectres rpe de chaque adduit de spin sont analyses et caracterises. Une etude de la geometrie des cycles pyrrolidinoxyle est abordee notamment