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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Avaliação morfoquantitativa nos músculos estriados esqueléticos de ratos wistar (Rattus norvegicus) dos efeitos da dieta utilizada na alimentação de crianças das zonas rurais de Moçambique / Structural, Ultrastructural and Morfoquantitative analysis of the effects caused in striated skeletal muscle of Wistar rats (Rattus norvegicus) subject to diet utilized in young children of rural Mozambique

Nhamposse, Catarina Tivane 29 November 2012 (has links)
Moçambique é um País da África Austral onde cerca de 55% da população vive abaixo da linha de pobreza absoluta com menos de uma refeição por dia sobrevivendo a muito custo com base em donativos. A insegurança alimentar e a nutrição extremamente precária, principalmente nas crianças, são fatores que induzem a níveis de Desnutrição crônica (DC) infantil em torno de 44%. Esta DC é responsável por um terço de mortes em menores de cinco anos. O objetivo deste estudo foi avaliar os efeitos que uma ração preparada com alimentos produzidos e consumidos pela população das zonas rurais de Moçambique exerceu no músculo gastrocnêmio de ratos wistar (Rattus norvegicus) alimentados com esta ração. Foram usados 75 ratos Wistar pesando aproximadamente 300 g divididos em três grupos: Nutrido ou controle (N), Desnutrido (D) e Moçambique ou grupo experimental (M), avaliados ao nascimento e ao desmame. Os animais foram mantidos sob as mesmas condições de alojamento, temperatura umidade e luz, porém com alimentação diferente consoante o grupo; Grupo N com ração normoproteica (20% de caseína), Grupo D com ração desnutrida (5% de caseína) e grupo M com ração de Moçambique. Em todos os grupos foi feita avaliação da massa corporal ao nascimento e desmame e coletado o músculo gastrocnêmio direito dos filhotes machos ao desmame para processamento. Foram realizadas cortes seriados de 10 µm de espessura em criostato e, as secções foram submetidas às técnicas da hematoxilina e eosina, picro-sirius, NADH-tr e análise em microscopio eletrônico de transmissão. A avaliação estatística das diferenças inter-grupos foi determinada pelos testes análise de variância, (ANOVA) e Tukey. Foram encontradas diferenças significativas entre os grupos N, D e M. Observou-se nos animais do grupo M uma grande variação no peso e tamanho que foi similar ao do grupo D; os mesmos apresentaram também alterações no formato das fibras musculares que exibiram contornos arredondados e, ainda, predominância de fibras colágenas tipo III tal como os desnutridos. Ultra estruturalmente os animais de Moçambique apresentaram um desalinhamento das linhas Z dos sarcômeros e rompimento das miofibrilas, diminuição na área de seção transversa e menor proporção de fibras glicolíticas e glicolítico-oxidativas, e maior porcentagem e área de seção transversa igual ao grupo D no respeitante ás fibras oxidativas. / Mozambique is a country of Southern Africa where about 55% of the population lives below the absolute poverty line with less than one meal per day, hardly surviving based on donations. Food insecurity and precarious nutrition, especially in children, are factors that induce to levels of 44% chronic infant malnutrition (DC). DC is responsible for one third of deaths in children under five years. The aim of this study was to evaluate morphoquantitative effects in gastrocnemius muscle of Wistar rats (Rattus norvegicus) fed with a diet utilized by people of rural areas of Mozambique. We used 75 Wistar rats weighing approximately 300 g divided in three groups: Nourished or control (N), Malnourished (D) and Mozambique or experimental group (M), measured at birth and weaning. The animals were kept under the same housing conditions, temperature, humidity and light, but fed with different diet depending on the group; Group N with normal protein diet (20% casein), Group D with hypo-proteic diet (5% casein) and group M with Mozambique diet. Body mass at birth and weaning was evaluated the right gastrocnemius muscle of male pups at weaning was colletcted for processing. Serial sections of 10 µm were performed in a cryostat prior to histology techniques of hematoxylin and eosin, picro-sirius, NADH-tr and analysis in transmission electron microscope. Statistical evaluation was determined by analysis of variance tests (ANOVA) and Tukey. Significant differences were found between groups N, D and M. Group M exhibit a great variation of body mass that was similar to group D; these animals (group M) also showed structural changes in muscle fiber which exhibited round-shaped contours, and a predominance of type III collagen similarly to malnourished group. Ultra structurally animals from Mozambique showed a disorganization of Z lines of sarcomeres and myofibrils disruption, decreased cross-sectional area and a smaller proportion of glycolytic and glycolytic-oxidative fibers, and higher percentage and cross-sectional area identical to group D with respect to oxidative fibers.
52

Estudos estruturais dos receptores nucleares humanos para os hormônios tireoidianos Isoforma ß1 (hTRß1) e para o ácido retinóico 9-cis Isoforma a (hRXRa) / Sctructural studies of the human thyroid hormone receptor isoform β e do ácido retinóico 9-cis isoforma α

Dias, Sandra Martha Gomes 27 August 2004 (has links)
Os receptores nucleares são de suma importância para os processos de sinalização intercelular nos eucariotos, uma vez que possuem a capacidade de convergir diferentes sinais internos e externos na regulação de programas genéticos. Estas proteínas funcionam, na sua maioria, como fatores de transcrição ativados por ligantes, sendo a via de comunicação direta entre as moléculas de sinalização e a resposta transcricional eliciada pelas mesmas. A programação genética, estabilizada ou modificada pelos receptores, afeta virtualmente todos os aspectos da vida dos organismos multicelulares, tais como a embriogênese, a homeostase, a reprodução, o crescimento e a morte celular. A regulação transcricional e a seletividade promovida por estas proteínas têm fomentado intensas pesquisas, as quais estão decifrando a complexa rede de eventos moleculares que relatam sua forma de ação. Será um desafio para o futuro o conhecimento completo das regras moleculares que definem sua maneira de promover o controle espacial e temporal da expressão gênica. Estas informações prometem trazer detalhes cruciais para o desenvolvimento de drogas mais eficientes e de grande valor terapêutico. Neste contexto, o principal objetivo dos estudos aqui apresentados foi o de aumentar o conhecimento sobre o comportamento e estrutura do receptor nuclear humano dos hormônios tireoidianos, isoforma β1 (hTRβ1), e do receptor nuclear humano do ácido retinóico 9-cis, isoforma ? (hRXRα). Para tal, aplicou-se a técnica de espalhamento de raios X a baixos ângulos para determinar-se, em solução, o envelope destes receptores contendo os domínios de ligação ao DNA e ao ligante. Paralelamente, investiu-se em diversas tentativas de cristalização dos mesmos. Os resultados obtidos permitiram a determinação da localização espacial dos diferentes domínios e as organizações quaternárias dos homodímeros e homotetrâmeros. Conseqüentemente, foram propostos os primeiros modelos estruturais de receptores nucleares contendo os domínios de ligação ao DNA e ao ligante. O comportamento oligomérico, em solução, do hTRβ1 também foi analisado qualitativamente. Verificou-se que a formação do homodímero e do homotetrâmero é influenciada pela presença do hormônio T3, pela concentração protéica, pelos domínios presentes e por mutações específicas. Estes estudos geraram a hipótese de que o receptor nuclear hTRβ1 é capaz de se autoreprimir. Até então, dentro da superfamília dos receptores nucleares, esta capacidade de autorepressão somente havia sido descrita para o receptor hRXRα. Por fim, cristalizou-se o domínio LBD do receptor hTRβ1 com os ligantes T3, Triac e GC-1. O objetivo foi o de determinar estruturas cristalográficas importantes para o futuro desenvolvimento de tiromiméticos de ação isoforma-seletiva. / In eukaryotes, nuclear receptors are of major importance for intercellular signaling because they join different intra and extracellular signals during regulation of genetic programs. The great majority of these proteins function as ligand activated transcription factors providing a direct link between signaling molecules and the transcriptional responses elicited by them. The genetic programs that these receptors establish or modify affect virtually all aspects of the multicellular organisms? life, such as embryogenesis, homeostasis, reproduction, cell growth, and death. Their gene-regulatory power and selectivity has prompted intense research which is now starting to decipher the complex network of molecular events involved in transcription regulation. The future challenge will be to uncover the molecular rules that define spatial and temporal control of gene expression. Such knowledge would be essential to the development of more efficient drugs with better therapeutic values. Therefore, the main purpose in this study was to extend the understanding on the behavior and the structure of human thyroid receptor, isoform ?1 (hTRβ1), and human retinoic acid X receptor, isoform ? (hRXRα). It was applied the small angle X-ray scattering technique to determine, in solution, the envelop of both receptors containing DNA and ligand binding domains. Beside this, several crystallization conditions were tried for both receptors. The results made possible to define the spatial localization of the domains and the quaternary structure of the homodimers and homotetramers. Consequently, we were able to propose the first structural models for nuclear receptors containing the DNA and ligand binding domains. The oligomeric behavior of the hTRβ1, in solution, was also analyzed qualitatively. We verified that it was influenced by the presence of T3 hormone, the protein concentration, the presence of both DNA and ligand binding domains, and by specific mutations. Based on these results, we were able to hypothesize that the hTRβ1 has the capacity of autorepression. Up to now, only the hRXRα, in the whole nuclear receptor superfamily, had been described to behave similarly. Finally, we crystallized the ligand binding domain of the hTRβ1 in the presence of the ligands T3, Triac, and GC-1. The objective was to solve crystallographic structures essential for the future development of tiromimetics with isoform-selective action.
53

Marta Astfalck-Vietz : photographs 1924-1936

Tubb, Katherine Anne January 2011 (has links)
The Berlin photographer Marta Astfalck-Vietz was active in the Weimar Republic, between 1924 and 1936. Her work was re-discovered in 1989 by the curator Janos Frecot, who staged a solo exhibition of her work in the Berlinische Galerie in 1991, and her archive, comprising just over 400 prints, is now held there. Since this show, the work of Marta Astfalck-Vietz has rarely been exhibited. In both German and Anglo-American scholarship it has received sporadic attention; the only text devoted to her work is still the catalogue to Frecot’s 1991 show. This thesis presents her photography to an Anglo-American audience, not as a compensatory exercise in retrieving a forgotten woman artist, but as a contribution to the existing body of literature on women in the Weimar era. Like other female artists of the period, Marta Astfalck-Vietz negotiated between her private experiences of life in the Republic and representations of its social and political tensions, which were circulated in novels, in films, on the stage, and in magazines. Her photographs address the issues of sex gender and race that preoccupy historians of Weimar Germany, confirming, confounding, and expanding our knowledge of the era.
54

New targetry possibilities from the TR-24

Zyuzin, A., Sader, J., Jenei, E., Tremblay, S., Thibault, P., Guerin, B. 19 May 2015 (has links) (PDF)
Introduction The TR-24 is relatively new to the cyclotron market and its advantages over lower energy PET cyclotrons have not yet been fully realized. A new high current [18F] fluoride production target that takes advantage of the higher energy and current afforded by the TR-24 has been developed. Material and Methods The TR-24 cyclotron presents challenges of producing conventional PET isotopes even with its variable energy capability (18–25 MeV). Simultaneous irradiation of two targets that require different proton energies is possible only using beam energy degrader. Due to the relatively wide energy window, the degrader design is not trivial, especially for the high current operation. For example, reduction of beam energy from 24 to 18 MeV would require the use of an approximately 1.5 mm thick aluminum degrader. At 100 μA this degrader would have to be capable of dissipating 700 W of beam power, which would be challenging to achieve with no cooling or using a conventional helium cooling window. However, cooling water used as a beam energy degrader can dissipate several kilowatts of beam energy and provide additional cooling for target material and window foils. FIGURE 1 demonstrates the concept of the water cooled target window. A standard 18F- water target with a 2.5 mL fill volume and a 30 degree beam incident angle was modified to accept the new water window. A 1 mm thick region of circulating cooling water was inserted between the vacuum and the product foil. The combined beam energy degradation caused by the vacuum foil (0.00012“ Havar), the cooling water (1 mm) and the target foil (0.00012“ Havar) was approximately 7 MeV for a 24 MeV incident proton energy. The target was installed on a target selector mounted directly on the TR-24 cyclotron. No additional beam focusing or steering devices were used to defocus or correct beam shape. A small recirculation water system was setup to supply cooling water for the degrader. A mixed bed ion exchange column was installed on the return line to trap N-13 and radioactive metal ions that could possibly be etched from the Havar foils. The water in the degrader was continually circulated in a closed loop providing cooling to the vacuum and target foils. An 800mL/min water flow through the degrader was generated by a low pressure water pump. Results Several tests were performed with O-16 water to establish current – pressure curve and to determine “burn through” current (FIGURE 2). Conclusion Initial tests demonstrated that the new F-18 target with a 1 mm water degrader is capable of accepting power levels in excess of 3.6 kW, operating at 150 μA. More testing is under way, including testing with H218O to determine the F-18 production capacity of this target. We will look into adapting this concept to all ACSI PET targets, including the high current F-18 produc-tion target which can potentially reach an operational current of 200 μA.
55

Estudos estruturais dos receptores nucleares humanos para os hormônios tireoidianos Isoforma ß1 (hTRß1) e para o ácido retinóico 9-cis Isoforma a (hRXRa) / Sctructural studies of the human thyroid hormone receptor isoform β e do ácido retinóico 9-cis isoforma α

Sandra Martha Gomes Dias 27 August 2004 (has links)
Os receptores nucleares são de suma importância para os processos de sinalização intercelular nos eucariotos, uma vez que possuem a capacidade de convergir diferentes sinais internos e externos na regulação de programas genéticos. Estas proteínas funcionam, na sua maioria, como fatores de transcrição ativados por ligantes, sendo a via de comunicação direta entre as moléculas de sinalização e a resposta transcricional eliciada pelas mesmas. A programação genética, estabilizada ou modificada pelos receptores, afeta virtualmente todos os aspectos da vida dos organismos multicelulares, tais como a embriogênese, a homeostase, a reprodução, o crescimento e a morte celular. A regulação transcricional e a seletividade promovida por estas proteínas têm fomentado intensas pesquisas, as quais estão decifrando a complexa rede de eventos moleculares que relatam sua forma de ação. Será um desafio para o futuro o conhecimento completo das regras moleculares que definem sua maneira de promover o controle espacial e temporal da expressão gênica. Estas informações prometem trazer detalhes cruciais para o desenvolvimento de drogas mais eficientes e de grande valor terapêutico. Neste contexto, o principal objetivo dos estudos aqui apresentados foi o de aumentar o conhecimento sobre o comportamento e estrutura do receptor nuclear humano dos hormônios tireoidianos, isoforma β1 (hTRβ1), e do receptor nuclear humano do ácido retinóico 9-cis, isoforma ? (hRXRα). Para tal, aplicou-se a técnica de espalhamento de raios X a baixos ângulos para determinar-se, em solução, o envelope destes receptores contendo os domínios de ligação ao DNA e ao ligante. Paralelamente, investiu-se em diversas tentativas de cristalização dos mesmos. Os resultados obtidos permitiram a determinação da localização espacial dos diferentes domínios e as organizações quaternárias dos homodímeros e homotetrâmeros. Conseqüentemente, foram propostos os primeiros modelos estruturais de receptores nucleares contendo os domínios de ligação ao DNA e ao ligante. O comportamento oligomérico, em solução, do hTRβ1 também foi analisado qualitativamente. Verificou-se que a formação do homodímero e do homotetrâmero é influenciada pela presença do hormônio T3, pela concentração protéica, pelos domínios presentes e por mutações específicas. Estes estudos geraram a hipótese de que o receptor nuclear hTRβ1 é capaz de se autoreprimir. Até então, dentro da superfamília dos receptores nucleares, esta capacidade de autorepressão somente havia sido descrita para o receptor hRXRα. Por fim, cristalizou-se o domínio LBD do receptor hTRβ1 com os ligantes T3, Triac e GC-1. O objetivo foi o de determinar estruturas cristalográficas importantes para o futuro desenvolvimento de tiromiméticos de ação isoforma-seletiva. / In eukaryotes, nuclear receptors are of major importance for intercellular signaling because they join different intra and extracellular signals during regulation of genetic programs. The great majority of these proteins function as ligand activated transcription factors providing a direct link between signaling molecules and the transcriptional responses elicited by them. The genetic programs that these receptors establish or modify affect virtually all aspects of the multicellular organisms? life, such as embryogenesis, homeostasis, reproduction, cell growth, and death. Their gene-regulatory power and selectivity has prompted intense research which is now starting to decipher the complex network of molecular events involved in transcription regulation. The future challenge will be to uncover the molecular rules that define spatial and temporal control of gene expression. Such knowledge would be essential to the development of more efficient drugs with better therapeutic values. Therefore, the main purpose in this study was to extend the understanding on the behavior and the structure of human thyroid receptor, isoform ?1 (hTRβ1), and human retinoic acid X receptor, isoform ? (hRXRα). It was applied the small angle X-ray scattering technique to determine, in solution, the envelop of both receptors containing DNA and ligand binding domains. Beside this, several crystallization conditions were tried for both receptors. The results made possible to define the spatial localization of the domains and the quaternary structure of the homodimers and homotetramers. Consequently, we were able to propose the first structural models for nuclear receptors containing the DNA and ligand binding domains. The oligomeric behavior of the hTRβ1, in solution, was also analyzed qualitatively. We verified that it was influenced by the presence of T3 hormone, the protein concentration, the presence of both DNA and ligand binding domains, and by specific mutations. Based on these results, we were able to hypothesize that the hTRβ1 has the capacity of autorepression. Up to now, only the hRXRα, in the whole nuclear receptor superfamily, had been described to behave similarly. Finally, we crystallized the ligand binding domain of the hTRβ1 in the presence of the ligands T3, Triac, and GC-1. The objective was to solve crystallographic structures essential for the future development of tiromimetics with isoform-selective action.
56

Avaliação morfoquantitativa nos músculos estriados esqueléticos de ratos wistar (Rattus norvegicus) dos efeitos da dieta utilizada na alimentação de crianças das zonas rurais de Moçambique / Structural, Ultrastructural and Morfoquantitative analysis of the effects caused in striated skeletal muscle of Wistar rats (Rattus norvegicus) subject to diet utilized in young children of rural Mozambique

Catarina Tivane Nhamposse 29 November 2012 (has links)
Moçambique é um País da África Austral onde cerca de 55% da população vive abaixo da linha de pobreza absoluta com menos de uma refeição por dia sobrevivendo a muito custo com base em donativos. A insegurança alimentar e a nutrição extremamente precária, principalmente nas crianças, são fatores que induzem a níveis de Desnutrição crônica (DC) infantil em torno de 44%. Esta DC é responsável por um terço de mortes em menores de cinco anos. O objetivo deste estudo foi avaliar os efeitos que uma ração preparada com alimentos produzidos e consumidos pela população das zonas rurais de Moçambique exerceu no músculo gastrocnêmio de ratos wistar (Rattus norvegicus) alimentados com esta ração. Foram usados 75 ratos Wistar pesando aproximadamente 300 g divididos em três grupos: Nutrido ou controle (N), Desnutrido (D) e Moçambique ou grupo experimental (M), avaliados ao nascimento e ao desmame. Os animais foram mantidos sob as mesmas condições de alojamento, temperatura umidade e luz, porém com alimentação diferente consoante o grupo; Grupo N com ração normoproteica (20% de caseína), Grupo D com ração desnutrida (5% de caseína) e grupo M com ração de Moçambique. Em todos os grupos foi feita avaliação da massa corporal ao nascimento e desmame e coletado o músculo gastrocnêmio direito dos filhotes machos ao desmame para processamento. Foram realizadas cortes seriados de 10 µm de espessura em criostato e, as secções foram submetidas às técnicas da hematoxilina e eosina, picro-sirius, NADH-tr e análise em microscopio eletrônico de transmissão. A avaliação estatística das diferenças inter-grupos foi determinada pelos testes análise de variância, (ANOVA) e Tukey. Foram encontradas diferenças significativas entre os grupos N, D e M. Observou-se nos animais do grupo M uma grande variação no peso e tamanho que foi similar ao do grupo D; os mesmos apresentaram também alterações no formato das fibras musculares que exibiram contornos arredondados e, ainda, predominância de fibras colágenas tipo III tal como os desnutridos. Ultra estruturalmente os animais de Moçambique apresentaram um desalinhamento das linhas Z dos sarcômeros e rompimento das miofibrilas, diminuição na área de seção transversa e menor proporção de fibras glicolíticas e glicolítico-oxidativas, e maior porcentagem e área de seção transversa igual ao grupo D no respeitante ás fibras oxidativas. / Mozambique is a country of Southern Africa where about 55% of the population lives below the absolute poverty line with less than one meal per day, hardly surviving based on donations. Food insecurity and precarious nutrition, especially in children, are factors that induce to levels of 44% chronic infant malnutrition (DC). DC is responsible for one third of deaths in children under five years. The aim of this study was to evaluate morphoquantitative effects in gastrocnemius muscle of Wistar rats (Rattus norvegicus) fed with a diet utilized by people of rural areas of Mozambique. We used 75 Wistar rats weighing approximately 300 g divided in three groups: Nourished or control (N), Malnourished (D) and Mozambique or experimental group (M), measured at birth and weaning. The animals were kept under the same housing conditions, temperature, humidity and light, but fed with different diet depending on the group; Group N with normal protein diet (20% casein), Group D with hypo-proteic diet (5% casein) and group M with Mozambique diet. Body mass at birth and weaning was evaluated the right gastrocnemius muscle of male pups at weaning was colletcted for processing. Serial sections of 10 µm were performed in a cryostat prior to histology techniques of hematoxylin and eosin, picro-sirius, NADH-tr and analysis in transmission electron microscope. Statistical evaluation was determined by analysis of variance tests (ANOVA) and Tukey. Significant differences were found between groups N, D and M. Group M exhibit a great variation of body mass that was similar to group D; these animals (group M) also showed structural changes in muscle fiber which exhibited round-shaped contours, and a predominance of type III collagen similarly to malnourished group. Ultra structurally animals from Mozambique showed a disorganization of Z lines of sarcomeres and myofibrils disruption, decreased cross-sectional area and a smaller proportion of glycolytic and glycolytic-oxidative fibers, and higher percentage and cross-sectional area identical to group D with respect to oxidative fibers.
57

Sonder la cinétique d'auto-assemblage de nano-capsules virales à haute résolution spatio-temporelle / Study of the kinetics of self-assembly of viral nanocapsules at high spatiotemporal resolution

Law-Hine, Didier 05 February 2016 (has links)
L’auto-assemblage de particules virales est un sujet de recherche qui suscite beaucoup d’intérêt dans le cadre de la physique de la matière molle, les mécanismes physiques d’auto-assemblage étant encore très mal compris. En particulier, le chemin cinétique à partir duquel les protéines virales interagissent avec le génome pour former des structures symétriques et monodisperses que sont les virus ne sont pas entièrement résolus. Dans une première partie de cette thèse, nous utilisons la technique de diffusion des rayons X aux petits angles résolue en temps (Time-Resolved Small-Angle X-Ray Scattering, TR-SAXS en anglais) pour observer les cinétiques d’auto-assemblage et de désassemblage de capsides vides formées à partir des protéines du virus de la marbrure chlorotique de la cornille (CCMV en anglais). Des modèles de cinétique chimique couplés à des concepts théorique de diffusion aux petits angles sont conçus pour extraire les intermédiaires de réaction, leur structure et leur temps de vie caractéristique. L’encapsulation d’ARN simple brin avec les protéines virales du CCMV est également étudiée dans cette thèse. A un pH neutre où les protéines ne s’assemblent pas spontanément pour former des capsides vides, des images de microscopie électronique montrent qu’il y a une population de complexes nucléoprotéiques désordonnés qui coexistent avec des capsides virales bien formées. De plus, les données de cinétique de TR-SAXS suggèrent que l’assemblage protéine-acide nucléique subit une réorganisation structurale dans laquelle les protéines rendent le complexe nucléoprotéique plus compact lorsqu’elles s’attachent à l’ARN. En milieu acide, les objets sont plus ordonnés, comme le suggère les images de microscopie électronique. Ces observations suggèrent que l’encapsulation d’ARN et la formation de virus avec leur haut degré de symétrie est probablement un assemblage à deux étapes, la première étant la formation du complexe nucléoprotéique et la deuxième l’acidification du milieu. / Viral assembly is an intriguing topic of biophysics that can be studied using concepts of soft matter physics. Although huge efforts have been made to synthesize hybrid or non-hybrid supramolecular assemblies with viral proteins, the fundamental mechanisms of self-assembly are yet poorly understood. In particular, the kinetic pathway in which the proteins interact with the genome to form highly symmetrical monodisperse architectures are not completely solved.In the first part of this thesis, the Time-Resolved Small-Angle X-Ray Scattering (TR-SAXS) technique is used to probe the kinetics of both self-assembly and disassembly of empty capsids built up from the proteins of the Cowpea Chlorotic Mottle Virus (CCMV). Chemical kinetics models coupled with concepts of SAXS theory are devised in order to extract information about the nature of the reaction intermediates, their structure and their typical lifetime. The encapsulation of ssRNA with CCMV capsid proteins is also examined in this thesis. At neutral pH where the capsid proteins do not spontaneously assemble in vitro into empty spherical capsids, electron microscopy images show that there is a non-negligible population of disordered nucleoprotein complexes that coexist with well-formed spherical viruses. Additionally, TR-SAXS kinetic data suggest that the protein-nucleic acid assembly undergoes a structural reorganization in which the capsid proteins make the nucleoprotein complexes more compact as they simultaneously bind the RNA. Upon acidification, the particles are well-formed viruses as suggested by electron microscopy images. These findings suggest that the encapsulation of RNA into well-formed viruses is likely a two-step assembly with a binding step and an acidification step.
58

Liability for negligent conduct in a heterogeneous society with reference to South African and German criminal law

Grant, Evadne 26 September 2023 (has links) (PDF)
The study of criminal law by lawyers has traditionally been confined to a consideration of general principles of criminal law and of specific crimes, the material or substantive criminal law.
59

The studio and collection of the 'American Raphael', Benjamin West, P.R.A. (1738-1820)

Weber, Kaylin Haverstock January 2013 (has links)
When the history painter Benjamin West (1738-1820) died in March 1820, he left behind a remarkable monument to his life and work in his residence at 14 Newman Street, in London’s fashionable West End. Here, he had created an elaborate ‘palace’ of art, dedicated to history painting and to himself – his artistic genius, his artistic heroes, and his unique transatlantic identity. This impressive establishment was nearly fifty years in the making and part of an elaborate strategy to develop an artistic reputation as the pre-eminent history painter of his generation. While his studio has been considered by scholars as a place of pilgrimage for dozens of American students, its physicality and contents have never been thoroughly explored. Using a variety of evidence, including bank records, contemporary descriptions, and visual material, this thesis reconstructs much of this important space and collection to reveal how it was shaped and utilised by West. It combines a documentation of the spaces and objects with an analysis of their use and meaning in terms of the painter’s engagement with art theory, pedagogy, practice, collecting, display, and legacy. West, who was History Painter to George III, inhabited 14 Newman Street from 1774 to 1820, a period of dramatic expansion and cultural ambition in the London art world. Indeed, this thesis argues that 14 Newman Street and its impressive contents were more than just a history painter’s ‘palace’ of art but a place symbolic of the ideals and ambitions of British art. Following an introduction that more fully defines the aims and scope of this thesis, four chapters explore the significance of West’s house, his collections, and their display in this context. Chapter one provides an overview of his home and studio, and considers how it was designed with West’s various audiences in mind. The scope and character of his impressive collection is examined in the second chapter with a particular focus on a selection of Old and New World objects that represent particular areas of strength within the corpus of the collection. Chapter three examines the collection as a public and private artistic resource for West and his students as well as a statement of his commitment to the grand tradition. In chapter four, West’s self-promotion and exhibition strategies at Newman Street are addressed, highlighted by his exhibition of The Death of Lord Nelson in 1806. Developed in the dynamic context of the establishment of the Royal Academy, the proliferation of public exhibitions, and ongoing debates about national art, West’s collection and studio at 14 Newman Street exemplified the aspirations of British art.
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Hybrid dialogues, situational strategies : producing postcolonial visual culture

Puzey, Jacqueline Michelle January 2014 (has links)
Hybrid Dialogues, Situation Strategies (hereafter referred to as HDSS) aims to explore the production of a postcolonial visual culture, through action research centered on producing and reflecting on collaborative visual artworks. The aim of the research is to use collaborative creative practice itself as the site of investigation into the way in which visual creative strategies can reflect and redefine the processes of constructing, inhabiting and exchanging complex definitions of postcolonial identities. It is suggested that the reflexive creative processes of art/design methods, can bring productive, transformative and complex re-visibilisations of accepted and contested postcolonial histories, through the application of the 'familiarity' of making clothes as a wider metaphor for exploring the construction of complex, postcolonial identities. In my thesis I set out my understanding of postcolonial visual culture and its histories and their relationship to my practice and the project presented. The research is implemented through Shade, a project situated within postcolonial visual culture and which interrogates the processes of producing that postcolonial culture. As the major practice project for HDSS, Shade is the key site of the generation of new knowledge. Through participation and reflection a new methodology of "fittings" has been developed, combining the principles of participatory action research and the craft process of tailoring, embroidering and fitting, so that the development and performance of the garments and accessories for Shade also become an important space for generation of new postcolonial cultural exchanges. Through this reflective practice, five principles of/for creative engagement with postcolonial cultures are identified. These five principles are; 'shared histories', 'radical familiarities', 'complicit spectacle', 'transgressive crafts', and 'democratic bespoke'. HDSS insists on becoming deeply implicated in acts of collaborative practice and on reflection on the construction of postcolonial identities. This has produced the key contribution to new knowledge, which can be summarised as the theory of 'shared cultural production', which suggests that no act of postcolonial cultural production can be theorised without genuine democratic participation in the conditions of its production.

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