Les membranes impliquées dans les processus bioénergétiques arborent une très grande densité de protéines, paramètre déterminant pour leur organisation supra-moléculaire. Dans ce travail, nous avons utilisé la bactérie thermophile Geobacillus stearothermophilus comme modèle pour étudier la formation de super-complexes de protéines membranaires, en vue d'une étude structurale. Nous avons purifié et caractérisé un super-complexe comprenant une menaquinol: cytochrome c oxydoréductase (b6c), un cytochrome c550 et une cytochrome c oxydase caa3. En combinant des titrations par spectroscopie optique et résonance paramagnétique électronique, nous avons pu déterminer les potentiels d'oxydo-réduction de la plupart des cofacteurs et combler ainsi une lacune dans l'étude des chaînes de transfert d'électrons utilisant des quinones à bas potentiel redox, les ménaquinones. Nous avons ainsi montré que les potentiels redox des cofacteurs du cytochrome b6c terminés par celui des quinones. Ce travail va à l'encontre de données partielles antérieures publiées, mais est en parfait accord avec les modèles du Q-cycle de Peter Mitchell. Les résultats obtenus ont des répercussions sur les rendements bioénergétiques des différents maillons de la chaîne de transfert. / Bioenergetic membranes present a high protein density - a crucial factor for their organizationinto super-complexes. This project uses the thermophilic bacteria Geobacillus stearothermophilusas a model to study the formation of membrane protein super-complexes with the aim of structuralstudies. We purified and characterized a super-complex between a menaquinone : cytochromec oxidoreductase (b6c), a cytochrome c550, and a cytochrome c oxidase caa3. Using both opticaland EPR spectroscopy methods, we performed the redox titrations of most of the redox cofactorsof the super-complex. Thus, these results enable a new understanding of menaquinone-usingelectron transport chains, showing that quinones’ redox potential determines the redox potentialof the cytochrome b6c’s cofactors. The conclusions differ from previous partial data, althoughthey fit perfectly with Peter Mitchell’s model of the Q-cycle. These unexpected redox potentialsimpact bioenergetic yields at different levels of the electron transfer chain.

Orientador: Lilian Lopes Martin da Silva / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Educação / Made available in DSpace on 2018-08-27T09:20:37Z (GMT). No. of bitstreams: 1 Arruda_RenataKellyde_D.pdf: 7009252 bytes, checksum: 53e2c7da1f6e9cc04ab05c80587e5be2 (MD5) Previous issue date: 2015 / Resumo: Um cenário peculiar nos é apresentado junto à movimentação diária das ruas de Belo Horizonte/MG: a convivência entre pressa matutina e leitura, atividade esta comumente imaginada como ação que requer silêncio e concentração. Esse panorama nos instiga a questionar discursos explícitos e recorrentes, como o de que "brasileiro lê pouco", ou a supervalorização, também comum, de alguns tipos de impresso em detrimento de outros. A essa visão generalista e universalista da prática da leitura, opomos uma visão que a toma e a afirma em sua multiplicidade de formas e possibilidades. São distintos objetos a ler, diferentes sujeitos leitores, muitos modos de fazer, muitas motivações etc. Neste sentido, nosso trabalho se propõe a conhecer, registrar e refletir sobre as práticas de leitura do jornal Super Notícia, vividas em certo contexto de época e lugar, envolvendo certa comunidade de leitores e resultando em formas e modos partilhados de ler e de produzir sentidos para o lido. Percorremos os três polos que de forma geral tencionam os impressos ¿ sua produção, circulação e recepção - procurando considerá-los de maneira interligada e tomando-os como orientadores de nossa investigação. Na produção, buscamos compreender aquilo que levou o jornal, em poucos anos, a equiparar-se a jornais centenários de grandes grupos de mídia brasileiros, ao menos em termos quantitativos. Nos polos da circulação e recepção do impresso, fomos em busca de suas formas de disseminação entre os leitores; de seus modos de acolhimento, emprego e leitura; das representações em jogo; bem como de possíveis interações existentes a partir da leitura do jornal Super Notícia. As principais referências teóricas que orientaram esta pesquisa encontram-se em Roger Chartier, Robert Darnton e seus estudos acerca da história cultural. Em Michel de Certeau, buscamos a relação leitor versus texto e cotidiano como uma dimensão de análise. Recorremos a entrevistas, observações diretas e fotografias envolvendo personagens dos três polos. Para compor nossa reflexão final, lançamos mão das transcrições das entrevistas, dos registros escritos em diários de campo e de imagens fotográficas / Abstract: A peculiar scenario is presented to the reader by the daily movement of the streets of Belo Horizonte/MG: the coexistence of morning rush and reading, this activity commonly thought of as action that requires silence and concentration. This panorama urges the reader to question explicit and recurrent discourses like that "Brazilian reads little" or overvaluation, also common, of some typesprinted genders over others. To this general and universal vision of the reading practice, we set another point of view that takes it and states it through its multiplicity of forms and possibilities. There are distinct objects to read, different readers, many ways of doing it, many motivations, etc.In this sense, we propose to find record and reflect upon the reading practices of the newspaper Super Notícia (Super News), experienced in a certain context of time and place, certain community of readers, in shared means and ways to read and to produce meanings to reading. We have followed the three poles that generally tense the printed word - its production, circulation and reception - trying to consider them interconnected and taking them as the horizons of our research.Along this research, we try to understand the reasons that led the newspaper, in a few years, to get to the level of centenarian papers of major Brazilian media groups, at least in quantitative terms. At the poles of circulation and reception of the printed word, we went in search of their forms of dissemination among the readers; their modes of reception, application and reading; representations at stake; as well as possible interactions existing from reading the newspaper Super Notícia.The main theoretical references that guided this research are Roger Chartier, Robert Darnton and their studies of cultural history. In Michel de Certeau we seek to the relationship between reader - text and everyday life as an analytic dimension.We put forward interviews, direct observations and photographs involving characters of the three poles. We used the transcripts of the interviews, of the written records in field diaries and photographic images to write down our final reflection / Doutorado / Educação, Conhecimento, Linguagem e Arte / Doutora em Educação

Orientador: Alex Antonelli / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-30T22:57:05Z (GMT). No. of bitstreams: 1 AlvarezDonado_ReneAlberto_M.pdf: 4171490 bytes, checksum: e9cef25e59956ed4e6201f408c88c61c (MD5) Previous issue date: 2016 / Resumo: Através de simulações de dinâmica molecular (MD) estudou-se o comportamento da viscosidade como função da temperatura para a liga Cu46Zr47Al7 que apresenta uma transição dinâmica frágil - forte. A interação entre as partículas foi modelada pelo potencial Modified Embeddded Atom Method (MEAM). As simulações de dinâmica molecular foram feitas usando as equações de Nosé-Hover e a viscosidade foi calculada pela fórmula de Green-Kubo. Observou-se que para uma temperatura reduzida (Tg/T ) de 0.8, o comportamento da viscosidade muda de frágil para forte. Usando a equação de Vogel-Fulcher-Tammann (VFT) em nossos resultados da simulação, observou-se que os valores da viscosidade calculados acima de 0.8 não são bem descritos por este ajuste, o que pode ser entendido como uma mudança no comportamento da viscosidade depois de atingir essa temperatura. A regressão feita usando a equação do VFT deu um valor limitante inferior para a temperatura de transição vítrea de 650K, o qual é um valor próximo da temperatura de transição vítrea reportada para estas ligas / Abstract: By means of molecular dynamic simulation (MD) we studied the behavior of the viscosity of a Cu46Zr47Al7 alloy, as a function of temperature, which displays a fragile - strong transition. Interactions between particles are modeled using the Modified Embedded Atom Method (MEAM). For the molecular simulations, we used the Nosé-Hoover equations, while the Green-Kubo formula gave us the viscosity. It was observed that, for a reduced temperature (Tg/T ) of 0.8, the behavior of the viscosity changes from fragile to strong. Using the Vogel-Fulcher-Tammann (VFT) equation in our results from the simulation, we noticed that the viscosity values above of 0.8 reaching this temperature. The regression achieved by VFT equation gave us a lowerbound value of 650K for the glass transition, which is very close to the glass transition temperature reported for this kind of alloys / Mestrado / Física / Mestre em Física / 1370420/2014 / CAPES

Neste trabalho apresentamos um estudo sistemático das propriedades ópticas e estruturais de super-redes de pontos quânticos auto-organizados de lnAs. As superredes foram crescidas por epitaxia de feixes moleculares sobre substratos de GaAs orientados na direção (100) com diferentes números de camadas de pontos quânticos e diferentes valores do espaçamento entre elas. As propriedades estruturais das super-redes foram observadas em seção transversal por microscopia eletrônica de transmissão convencional e de alta resolução. Os resultados permitem determinar a evolução da altura, do diâmetro e da densidade dos pontos quânticos em função da modificação da espessura da camada de espaçamento. Também observamos que pontos quânticos empilhados muito próximos tendem a relaxar através da formação de defeitos estruturais identificados como micromaclas. As propriedades ópticas foram investigadas por meio de fotoluminescência a baixa temperatura, bem como variando-se a potência de excitação e a temperatura da amostra. Reportamos um novo comportamento da posição do pico de fotoluminescência com a redução da espessura da camada de espaçamento. Interpretamos este comportamento em termos de modificação do tamanho dos pontos quânticos, acoplamento eletrônico, relaxamento parcial da tensão e formação de centros de recombinação não-radiativa. Usando essas interpretações, calculamos os espectros de fotoluminescência das super-redes, que ajustam muito bem os dados experimentais. As interpretações propostas são também sustentadas pela influência da espessura da camada de espaçamento na intensidade integrada de fotoluminescência e nas energias de ativação / In this work we present a comprehensive and systematic study of the optical and structural properties of self-organized InAs quantum dots superlattices. The superlattices were grown by molecular beam epitaxy on GaAs (100) substrates with different number of quantum dot layers and different thicknesses between these layers. Their structural properties have been observed by conventional and highresolution cross-sectional transmission electron microscopy. The results allow us to sketch the evolution of the dot height, diameter and density when the spacer layer thickness is modified in a wide range. We also observe that closely stacked quantum dots tend to relax through the formation of structural defects identified as microtwins. The optical properties have been investigated by means of conventional, power dependent- and temperature dependent photoluminescence. We report for the first time on an unusual behavior of the photoluminescence peak position when the spacer layer thickness is reduced. We interpret this behavior in terms of quantum dot size modification, electronic coupling, partial strain relaxation and non-radiative recombination centers formation. Using these interpretations, we then produce simulated photoluminescence spectra that fit very well the experimental data. These interpretations are further supported by the spacer layer thickness influence upon photoluminescence integrated intensity and activation energies.

Video super-resolution (VSR) aims to recover a realistic high-resolution (HR) frame from its corresponding center low-resolution (LR) frame and several neighbouring supporting frames. The neighbouring supporting LR frames can provide extra information to help recover the HR frame. However, these frames are not aligned with the center frame due to the motion of objects. Recently, many video super-resolution methods based on deep learning have been proposed with the rapid development of neural networks. Most of these methods utilize motion estimation and compensation models as preprocessing to handle spatio-temporal alignment problem. Therefore, the accuracy of these motion estimation models are critical for predicting the high-resolution frames. Inaccurate results of motion compensation models will lead to artifacts and blurs, which also will damage the recovery of high-resolution frames. We propose an effective wide activated separate 3 dimensional (3D) Convolution Neural Network (CNN) for video super-resolution to overcome the drawback of utilizing motion compensation models. Separate 3D convolution factorizes the 3D convolution into convolutions in the spatial and temporal domain, which have benefit for the optimization of spatial and temporal convolution components. Therefore, our method can capture temporal and spatial information of input frames simultaneously without additional motion evaluation and compensation model. Moreover, the experimental results demonstrated the effectiveness of the proposed wide activated separate 3D CNN.

Nanoscopic spatial reorganization of selectin ligands, CD44 and PSGL-1, during the initial step of hematopoietic stem/progenitor cell (HSPC) homing, tethering and rolling of migrating cells over E-selectins, has been recently reported. However, the exact spatial distribution of these ligands and their spatial reorganization during the cell rolling on E-selectins are still an open question. The spatiotemporal characterization at the nanoscale level requires high resolution imaging methods. In this study, I quantitatively characterize nanoscopic spatiotemporal behavior of the selectin ligands on the migrating cells to understanding the molecular mechanism of the cell rolling at the nanoscale level by means of a microfluidics-based 3D super-resolution fluorescence microscopy technique. The obtained results suggest that PSGL-1 on the cell shows significant change in the axial distribution on the cell during the cell rolling on E-selectin whereas the spatial distribution of CD44 along the axial direction is not affected significantly by the cell rolling. These findings indicate that each selectin ligand has a distinct contribution to the initial step of the HSPC homing because of their distinct spatial localizations on the cells that regulate at least partly the accessibility of these ligands to the surface E-selectin.

Spatial and temporal dynamics of polymer chains play critical roles in their rheological properties, which have a significant influence on polymer processing and fabrication of polymer-based (nano) materials. Many theoretical and experimental studies have aimed at understanding polymer dynamics at the molecular level that give rise to its bulk phase properties. While much progress has been made in the field over the past ~60 years, many aspects of polymers are still not understood, especially in complicated systems such as entangled fluids and polymers of different topologies. In addition, the physical properties of biological macromolecules, i.e. DNA, are expected to affect the spatial organization of chromosome in a cell, which has the potential impact on a broad epigenetics research. Here, we propose new methods for simultaneous visualization of diffusive motion and conformational dynamics of individual polymer chains, two most important factors that characterize polymer dynamics, based on a new single-molecule tracking technique, cumulative-area (CA) tracking method. We demonstrate the applicability of the CA tracking to the quantitative characterization of the motion and relaxation of individual topological polymer molecules under entangled conditions, which is possible only by using the newly-developed CA tracking, using fluorescently-labeled linear and cyclic dsDNA as model systems. We further extend the technique to multi-color CA tracking that allows for the direct visualization and characterization of motion and conformation of interacting molecules. We also develop a new imaging method based on recently developed 3D super-resolution fluorescence microscopy technique, which allows direct visualization of nanoscale motion and conformation of the single molecules that is not possible by any other methods. Using these techniques, we investigate spatial and temporal dynamics of polymers at the single-molecule level, with special emphasis on the effect of topological forms of the molecules and the confined geometry on their spatiotemporal dynamics. Our results demonstrate that the new methods developed in this thesis provide an experimental platform to address key questions in the entangled topological polymer dynamics. The research will provide a platform for developing new polymer-based materials and open the possibility of studying spatial organization of DNA in a confined geometry from physics point of view.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第22251号 / 理博第4565号 / 新制||理||1655(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 嶺重 慎, 准教授 前田 啓一, 教授 長田 哲也 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

京都大学 / 新制・課程博士 / 博士(医科学) / 甲第23115号 / 医科博第126号 / 新制||医科||8(附属図書館) / 京都大学大学院医学研究科医科学専攻 / (主査)教授 伊佐 正, 教授 髙橋 良輔, 教授 井上 治久 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Video super-resolution (VSR) methods align and fuse consecutive low-resolution frames to generate high-resolution frames. One of the main difficulties for the VSR process is that video contains various motions, and the accuracy of motion estimation dramatically affects the quality of video restoration. However, standard CNNs share the same receptive field in each layer, and it is challenging to estimate diverse motions effectively. Neuroscience research has shown that the receptive fields of biological visual areas will be adjusted according to the input information. Diverse receptive fields in temporal and spatial dimensions have the potential to adapt to various motions, which is rarely paid attention in most known VSR methods. In this thesis, we propose to provide adaptive receptive fields for the VSR model. Firstly, we design a multi-kernel 3D convolution network and integrate it with a multi-kernel deformable convolution network for motion estimation and multiple frames alignment. Secondly, we propose a 2D multi-kernel convolution framework to improve texture restoration quality. Our experimental results show that the proposed framework outperforms the state-of-the-art VSR methods.