Desenvolupament d'un Videojoc en 3D basat en OPENGL

L'objectiu d'aquest treball ha estat desenvolupar un videojoc en un entorn de tres dimensions utilitzant les llibreries gràfiques d'OpenGL. Aquesta aplicació s'ha desenvolupat en Java, cosa que dóna més independència perquè aquesta és precisament la filosofia d'aquest llenguatge de programació.

Les deux visages de l'autophagie dans le système nerveux [The two faces of autophagy in the nervous system].

Autophagy is a cellular mechanism for degrading proteins and organelles. It was first described as a physiological process essential for maintaining homeostasis and cell survival, but understanding its role in conditions of stress has been complicated by the recognition of a new type of cell death ("type 2") characterized by deleterious autophagic activity. This paradox is important in the central nervous system where the activation of autophagy seems to be protective in certain neurodegenerative diseases but deleterious in cerebral ischemia. The development of new therapeutic strategies based on the manipulation of autophagy will need to take into account these opposing roles of autophagy.

Brain damage in methylmalonic aciduria: 2-methylcitrate induces cerebral ammonium accumulation and apoptosis in 3D organotypic brain cell cultures.

BACKGROUND: Methylmalonic aciduria is an inborn error of metabolism characterized by accumulation of methylmalonate (MMA), propionate and 2-methylcitrate (2-MCA) in body fluids. Early diagnosis and current treatment strategies aimed at limiting the production of these metabolites are only partially effective in preventing neurological damage. METHODS: To explore the metabolic consequences of methylmalonic aciduria on the brain, we used 3D organotypic brain cell cultures from rat embryos. We challenged the cultures at two different developmental stages with 1 mM MMA, propionate or 2-MCA applied 6 times every 12 h. In a dose-response experiment cultures were challenged with 0.01, 0.1, 0.33 and 1 mM 2-MCA. Immunohistochemical staining for different brain cell markers were used to assess cell viability, morphology and differentiation. Significant changes were validated by western blot analysis. Biochemical markers were analyzed in culture media. Apoptosis was studied by immunofluorescence staining and western blots for activated caspase-3. RESULTS: Among the three metabolites tested, 2-MCA consistently produced the most pronounced effects. Exposure to 2-MCA caused morphological changes in neuronal and glial cells already at 0.01 mM. At the biochemical level the most striking result was a significant ammonium increase in culture media with a concomitant glutamine decrease. Dose-response studies showed significant and parallel changes of ammonium and glutamine starting from 0.1 mM 2-MCA. An increased apoptosis rate was observed by activation of caspase-3 after exposure to at least 0.1 mM 2-MCA. CONCLUSION: Surprisingly, 2-MCA, and not MMA, seems to be the most toxic metabolite in our in vitro model leading to delayed axonal growth, apoptosis of glial cells and to unexpected ammonium increase. Morphological changes were already observed at 2-MCA concentrations as low as 0.01 mM. Increased apoptosis and ammonium accumulation started at 0.1 mM thus suggesting that ammonium accumulation is secondary to cell suffering and/or cell death. Local accumulation of ammonium in CNS, that may remain undetected in plasma and urine, may therefore play a key role in the neuropathogenesis of methylmalonic aciduria both during acute decompensations and in chronic phases. If confirmed in vivo, this finding might shift the current paradigm and result in novel therapeutic strategies.

Helical tomotherapy (HT) for the treatment of anal canal cancer: preliminary clinical results, and dosimetric comparison between HT and intensity-modulated or 3D conformal radiotherapy

Background: To report a single-center experience in 19 patients (pts) with anal canal cancer treated with helical tomotherapy (HT) and concurrent chemotherapy, and compare the dosimetric results with fixed-field intensitymodulated radiotherapy (IMRT) and 3D conformal radiotherapy (3D RT). Materials and Methods: Between 2007 and 2008, 19 consecutive pts were treated with HT and concurrent CT for anal canal cancer. Median age was 59 years (range, 38−83), and female/male ratio was 14/5. The majority of the pts had T2 or T3 tumours (68.4%), and 52.6% had positive lymph nodes. In all 19 pts, pelvic and inguinal nodes, and tumour irradiation was given using HT upto a median dose of 36 Gy (1.8 Gy/fr) followed by a 1-week gap. A boost dose of 23.4 Gy (1.8 Gy/fr) was delivered to the tumour and involved nodes using 3DRT (n = 12), HT (n = 6), or IMRT (n = 1). Simultaneous integrated boost was used in none of the pts. All but one patient with a T1N0 tumour received concomitant mitomycin/5- fluorouracil (n = 12) or mitomycin/capecitabin (n = 7) CT. Toxicity was scored according to the Common Terminology Criteria for Adverse Events (NCICTCAE v3.0). HT plans and treatments were generated using Tomotherapy, Inc., software and hardware; and 3D or IMRT boost plans with the CMS treatment planning system (TPS), using 6−18 MV photons from a Siemens Primus accelerator. For dosimetric comparison, computed tomography data sets of 10 pts were imported into the TPS, and 3D and 5-field step-andshoot IMRT plans were generated for each case. Plans were optimized with the aim of assessing organs at risk (OAR) and healthy-tissue sparing while enforcing highly conformal target coverage, and evaluated by dose-volume histograms (DVH) of planning target volumes (PTV) and OAR. Results: With a median follow-up of 13 months (range, 3−18), all pts are alive and well; except one patient developing local recurrence at 12 months. No patient developed grade 3 or more acute toxicity. No unplanned treatment interruption was necessary because of toxicity. With 360-degree-of-freedom beam projection, HT showed an advantage over 3D or IMRT plans in terms of dose conformity around the PTV, and dose gradients were steeper outside the PTV, resulting in reduced doses to OARs. Using HT, acute toxicity was acceptable, and seemed to be better than historical standards. Conclusion: We conclude that HT combined with concurrent chemotherapy for anal canal cancer is effective and tolerable. Compared to 3DRT or 5-field IMRT, there is better conformity around the PTV, and OAR sparing.

Online Robust 3D Mapping Using Structure from Motion Cues

This paper presents a complete solution for creating accurate 3D textured models from monocular video sequences. The methods are developed within the framework of sequential structure from motion, where a 3D model of the environment is maintained and updated as new visual information becomes available. The camera position is recovered by directly associating the 3D scene model with local image observations. Compared to standard structure from motion techniques, this approach decreases the error accumulation while increasing the robustness to scene occlusions and feature association failures. The obtained 3D information is used to generate high quality, composite visual maps of the scene (mosaics). The visual maps are used to create texture-mapped, realistic views of the scene

Accuracy estimation of a new omnidirectional 3D vision sensor

We present a computer vision system that associates omnidirectional vision with structured light with the aim of obtaining depth information for a 360 degrees field of view. The approach proposed in this article combines an omnidirectional camera with a panoramic laser projector. The article shows how the sensor is modelled and its accuracy is proved by means of experimental results. The proposed sensor provides useful information for robot navigation applications, pipe inspection, 3D scene modelling etc

Overview of coded light projection techniques for automatic 3D profiling

Obtaining automatic 3D profile of objects is one of the most important issues in computer vision. With this information, a large number of applications become feasible: from visual inspection of industrial parts to 3D reconstruction of the environment for mobile robots. In order to achieve 3D data, range finders can be used. Coded structured light approach is one of the most widely used techniques to retrieve 3D information of an unknown surface. An overview of the existing techniques as well as a new classification of patterns for structured light sensors is presented. This kind of systems belong to the group of active triangulation method, which are based on projecting a light pattern and imaging the illuminated scene from one or more points of view. Since the patterns are coded, correspondences between points of the image(s) and points of the projected pattern can be easily found. Once correspondences are found, a classical triangulation strategy between camera(s) and projector device leads to the reconstruction of the surface. Advantages and constraints of the different patterns are discussed

Implementation of a robust coded structured light technique for dynamic 3D measurements

This paper presents the implementation details of a coded structured light system for rapid shape acquisition of unknown surfaces. Such techniques are based on the projection of patterns onto a measuring surface and grabbing images of every projection with a camera. Analyzing the pattern deformations that appear in the images, 3D information of the surface can be calculated. The implemented technique projects a unique pattern so that it can be used to measure moving surfaces. The structure of the pattern is a grid where the color of the slits are selected using a De Bruijn sequence. Moreover, since both axis of the pattern are coded, the cross points of the grid have two codewords (which permits to reconstruct them very precisely), while pixels belonging to horizontal and vertical slits have also a codeword. Different sets of colors are used for horizontal and vertical slits, so the resulting pattern is invariant to rotation. Therefore, the alignment constraint between camera and projector considered by a lot of authors is not necessary

Role of ALK gene and mutations in initiation and progression of neuroblastoma

Introduction Le neuroblastome (NB) est la tumeur maligne solide extra-crânienne la plus fréquente chez l'enfant. Sa présentation clinique est très hétérogène, allant d'une tumeur localisée à une atteinte métastatique sévère. Malgré des traitements agressifs, environ 55% des NB de hauts risques sont actuellement résistants aux thérapies. L'espoir réside dans le développement de traitements ciblant les mécanismes moléculaires responsables du développement et de la progression du NB. Le gène Anaplastic Lymphoma Kinase (ALK) codant pour un récepteur tyrosine kinase a été particulièrement étudié ces dernières années car il est muté, amplifié ou surexprimé dans une majorité des NBs. Le but de ce projet était d'investiguer le rôle de ALK-wt, ainsi que de ces deux plus fréquentes mutations, ALK- F1174L et ALK-R1245Q, dans l'oncogenèse du NB. Le NB étant originaire des cellules de la crête neurale, nous avons analysé le potentiel oncogénique de ces différentes formes de ALK dans des cellules progénitrices de la crête neurale (NCPC). Méthode Des NCPC de souris (JoMal), possédant un c-MycER inductible pour leur maintien en culture in vitro, ont été transduites par un rétrovirus permettant l'expression stable de ALK-wt, ALK-F1174L et ALK-R1245Q. Des tests in vitro ont d'abord été effectués pour tester le système c-MycER, la stabilité de nos cellules transduites, leur phénotype, leur capacité de croissance et leur tumorigénicité. Les cellules transduites ont ensuite été injectées dans des souris immunosupprimées en sous-cutané, puis en orthotopique, c'est-à-dire dans leur glande surrénale, afin de mesurer leur tumorigénicité in vivo. Résultats La transduction et l'expression stable de ALK n'ont pas modifié le phénotype indifférencié des JoMal, ni de manière significative la capacité de croissance des cellules in vitro en absence d'activation de c-MycER. Par contre, lorsque c-MycER est actif, les cellules porteuses des mutations Fl 174L et R1245Q ont montré une meilleure capacité de prolifération et de formation de colonies, par rapport aux JoMal-ALK-wt et aux cellules contrôles en culture 3D dans de la méthylcellulose et dans un test de formation de neurosphères. In vivo, les souris injectées avec les cellules JoMal-ALK- F1174L en sous-cutané ou dans la glande surrénale ont rapidement développé des tumeurs, suivies par le groupe JoMal-ALK-R1245Q et le groupe JoMal-ALK-wt, alors que les groupes de souris contrôles n'ont présenté aucune tumeur. En orthotopique, nous avons obtenu 5/6 tumeurs ALK-F1174L, 7/7 tumeurs ALK-R1245Q et 6/7 tumeurs ALK-wt. Les tumeurs sous-cutanées ne présentaient pas de différences morphologiques et histologiques entre les différents groupes et montraient une histologie compatible avec un NB. Les tumeurs orthotopiques restent encore à analyser. Conclusion Cette étude a permis de démontrer que les mutations activatrices Fl 174L et R1245Q ont des propriétés tumorigéniques in vitro dans des NCPC et in vivo tandis que la forme sauvage de ALK montre une capacité oncogénique uniquement in vivo. Bien que la caractérisation des tumeurs orthotopiques n'a pas encore été effectuée, l'analyse des tumeurs sous-cutanées nous suggère que l'expression de ALK- wt ou muté est suffisante pour induire la formation de NB à partir des cellules progénitrices de la crête neurale. Le gène ALK semble donc jouer un rôle important dans l'oncogénèse du NB, aussi bien par la présence de mutations activatrices que par sa fréquente surexpression.

Using 3D surface datasets to understand landslide evolution: From analogue models to real case study

Early detection of landslide surface deformation with 3D remote sensing techniques, as TLS, has become a great challenge during last decade. To improve our understanding of landslide deformation, a series of analogue simulation have been carried out on non-rigid bodies coupled with 3D digitizer. All these experiments have been carried out under controlled conditions, as water level and slope angle inclination. We were able to follow 3D surface deformation suffered by complex landslide bodies from precursory deformation still larger failures. These experiments were the basis for the development of a new algorithm for the quantification of surface deformation using automatic tracking method on discrete points of the slope surface. To validate the algorithm, comparisons were made between manually obtained results and algorithm surface displacement results. Outputs will help in understanding 3D deformation during pre-failure stages and failure mechanisms, which are fundamental aspects for future implementation of 3D remote sensing techniques in early warning systems.