[pt] Rótulos virtuais são utilizados em aplicações de computação gráfica para representar informações textuais dispostas sobre superfícies geométricas. Tais informações consistem em nomes, numerações, ou outros dados relevantes que precisem ser notados rapidamente quando um usuário examina os objetos da cena. Este trabalho tem como foco os chamados modelos massivos, como modelos CAD (Computer Aided Design) de refinarias de petróleo, os quais possuem um grande número de primitivas geométricas cujo rendering apresenta um alto custo computacional. Em grandes projetos de engenharia, é desejável a visualização imediata de informações específicas de cada objeto ou de partes do modelo, as quais, se exibidas por meio de técnicas convencionais de texturização podem extrapolar os recursos computacionais disponíveis. Nesta dissertação desenvolvemos uma forma de exibir, em tempo real, rótulos virtuais com informações distintas, nas superfícies de objetos de modelos massivos. A técnica é implementada inteiramente em GPU, não apresenta perda significativa de desempenho e possui um baixo gasto de memória. Os objetos de modelos CAD são o foco principal do trabalho, apesar de a solução poder ser utilizada em outros tipos de objetos desde que suas coordenadas de textura sejam corretamente ajustadas. / [en] Virtual Labels are used in computer graphics applications to represent textual information arranged on geometric surfaces. Such information consists of names, numbering, or other relevant data that need to be noticed quickly when a user scans the objects in the scene. This paper focuses on the so-called massive models, as CAD models (Computer Aided Design) of oil refineries, which have a large number of geometric primitives whose rendering presents a high computational cost. In large engineering projects, the immediate visualization of information specific to each object or parts of the model is desirable, which, if displayed by conventional texturing techniques can extrapolate the available computational resources. In this work we have developed a way to view, in real time, virtual labels with different information on the surfaces of objects in massive models. The technique is implemented entirely on the GPU, shows no significant loss of performance and low memory cost. CAD models objects are the main focus of the work, although the solution can be used in other types of objects once their texture coordinates are adjusted correctly.

Les dépôts intracellulaires de la protéine Tau agrégée sont la caractéristique commune des tauopathies, une famille de maladies neurodégénératives dont fait partie la maladie d’Alzheimer. Alors que les isoformes de Tau contenant trois (3R) ou quatre (4R) domaines de liaison aux microtubules sont retrouvées à des niveaux similaires dans le cerveau des individus sains, elles diffèrent au sein des inclusions intracellulaires en fonction des tauopathies. Notre étude repose sur l’identification de déterminants structuraux communs et distincts de fibres de Tau 3R et 4R. Pour cela deux approches de protéomique structurale complémentaires ont été mises au point à partir de fibres de Tau 1N3R et 1N4R produites in vitro. La première stratégie, reposant sur l’utilisation de protéolyses ménagées, nous a permis d’identifier les fragments protéolytiques qui composent un « code-barre » moléculaire propre à chaque assemblage. La seconde stratégie a utilisé un marquage chimique covalent des lysines accessibles suivi de l’analyse qualitative et quantitative des acides aminés marqués par spectrométrie de masse. Nous avons ainsi pu montrer que la partie N-terminale de la protéine était accessible au sein des fibres 1N3R et 1N4R tandis que la région C-terminale de la protéine est protégée pour Tau 1N3R et accessible au solvant pour Tau 1N4R. Nos résultats ouvrent la voie à de nouveaux outils moléculaires pour discriminer les tauopathies. / Intracellular deposits of Tau protein aggregates are the common hallmark of tauopathies, a range of neurodegenerative diseases including Alzheimer's disease. Levels of tau with three (3R) or four (4R) microtubule binding repeats are found similar in the normal adult brain, whereas they differ in neuropathological intracellular Tau inclusions, according to the type of tauopathy. Our study consists of the identification of common and different structural molecular determinants of 3R and 4R Tau fibrils. To this end, two proteomic approaches were optimized using 1N3R and 1N4R recombinant fibrils. The first strategy, using limited proteolysis, allowed us to identify the proteolytic fragments composing the molecular “bar-code” for each type of fibril. The second strategy we optimized used chemical covalent surface labelling of accessible lysines, and qualitative and quantitative analysis of the biotinylated residues using mass spectrometry. We show that, while the N-terminal part of the protein remains accessible within 1N3R and 1N4R fibrils, the C-terminal region is protected within 1N3R yet solvent accessible for 1N4R assemblies. Our results pave the way to new molecular tools to discriminate tauopathies.