Flexible b-spline model parameterization designed for reflection tomography

International audienceReflection tomography is an efficient method to determine a subsurface velocity model that best fits the traveltime data associated to the main events picked on the seismic sections. A careful choice of the model representation has to be done: a blocky model representation based on regular gridded b-spline functions has been proposed. This flexible parameterization allows accurate and robust inversion but can lead to a huge number of parameters. An adaptive parameterization that enables to account for local complexities and inhomogeneous ray coverage is considered

Animals bearing malignant grafts reject normal grafts that express through gene transfer the same antigen.

Breaking the state of immunological unresponsiveness of tumor-bearing individuals to cancer is a prerequisite for active or passive tumor-specific immunotherapy. To study this problem the immunogenic MHC class I antigen, K216 was transfected into a progressor tumor. The transfected tumors were regularly rejected by normal mice but grew progressively in mice bearing nontransfected tumors. In addition, transgenic mice were derived to obtain normal cells and tissues expressing the same K216 gene product. Normal mice rejected K216-positive normal or malignant tissue grafts and generated K216-specific CTL in vitro and in vivo in response to these challenges. In contrast, mice bearing nontransfected tumors, though rejecting K216-positive nonmalignant tissue grafts, did not reject K216-positive tumors nor generate K216-specific CTL in response to K216-positive tumor cells. Mice bearing K216-positive tumors also rejected the nonmalignant K216-positive tissue grafts, but this in vivo response failed to lead to rejection of the simultaneously present tumor graft expressing the same antigen; in fact, immunity had no measurable effect whatsoever on tumor size or incidence and caused no selection for antigen loss variants. Taken together, the present findings suggest that transfer of expression of a target antigen into nonmalignant cells provides a way for obtaining effective stimulation of antigen-specific CTL in tumor-bearing mice, but that additional manipulations will be required to cause immunological rejection of established tumors

Adaptive model parameterization designed for reflexion tomography

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Discovering RNA-Protein Interactome by Using Chemical Context Profiling of the RNA-Protein Interface

SummaryRNA-protein (RNP) interactions generally are required for RNA function. At least 5% of human genes code for RNA-binding proteins. Whereas many approaches can identify the RNA partners for a specific protein, finding the protein partners for a specific RNA is difficult. We present a machine-learning method that scores a protein’s binding potential for an RNA structure by utilizing the chemical context profiles of the interface from known RNP structures. Our approach is applicable even when only a single RNP structure is available. We examined 801 mammalian proteins and find that 37 (4.6%) potentially bind transfer RNA (tRNA). Most are enzymes involved in cellular processes unrelated to translation and were not known to interact with RNA. We experimentally tested six positive and three negative predictions for tRNA binding in vivo, and all nine predictions were correct. Our computational approach provides a powerful complement to experiments in discovering new RNPs

Allergies respiratoires, pollens et polluants

National audienceFor 30 years, an increased incidence of respiratory allergy and asthma has been observed, particularly in children and young people living in urban areas of developed countries. A genetic origin is unlikely due to the rapidity of this increase and environmental factors (diet, lifestyle, exposure to xenobiotics...) should be involved. Epidemiological studies have shown that atmospheric pollutants may play a role. They could have an effect on the respiratory tract by inducing irritation, inflammation, airway hyperresponsiveness or enhancing respiratory allergies (adjuvant effect) or they could have an effect on the aeroallergens, in particular the pollens. Experimental studies have shown that pollen exposure to pollutants induce enhanced deformation or fracture of the external envelope linking to an enhanced liberation of intracytoplasmic allergenic granules and induce also a qualitative and quantitative modification of allergens. However, few experimental studies have shown that pollutant-exposed pollens are more allergenic that "clean" pollens. One important point to consider is the enhanced granule liberation by exposed pollens. Due to the small size of the granules, the allergen bioavailability may increase, leading to higher incidence of respiratory allergies.Depuis 30 ans, une incidence accrue des allergies respiratoires est observée, notamment chez les enfants et les adolescents vivant dans les zones urbaines des pays industrialisés. Il est admis que cette augmentation est trop rapide pour être liée à des facteurs génétiques et que d'autres facteurs, notamment environnementaux (alimentation, mode de vie, contact avec des xénobiotiques...) sont impliqués. Les études épidémiologiques montrent que les polluants de l'air en particulier semblent jouer un rôle important dans l'incidence des allergies. Ils peuvent agir soit par action au niveau du système respiratoire, en provoquant une irritation, une inflammation, une augmentation de l'hyperréactivité bronchique non spécifique ou en potentialisant une réponse allergique pré-existante (effet adjuvant), soit par action au niveau des aéroallergènes, dont les pollens représentent la majeure partie. Les principaux effets observés expérimentalement sont une augmentation des déformations et fractures de l'enveloppe externe conduisant à une libération accrue de granules intracytoplasmiques, eux-mêmes allergisants et une modification quantitative et qualitative des allergènes. Peu de travaux ont toutefois clairement mis en évidence une augmentation du potentiel allergisant des pollens après exposition aux polluants. Une piste à explorer reste la libération plus importante des granules intrapolliniques qui, de part leur petite taille, pourraient augmenter la biodisponibilité des allergènes et donc la fréquence et la gravité des allergies respiratoires

Development and application of an aero-hydro-servo-elastic coupling framework for analysis of floating offshore wind turbines

In order to enhance simulation capabilities of existing numerical tools for the design of floating offshore wind turbines (FOWTs), this study has developed and implemented a coupling framework (F2A) that is capable of predicting nonlinear dynamics of a FOWT subjected to wind, wave and current loadings. F2A integrates all the advantages of FAST in efficiently examining aero-servo-elastic effects with all the numerical capabilities of AQWA (e. g. nonlinear hydrodynamics, mooring dynamics and material nonlinearity) for the dynamic analysis of a FOWT. The verification of F2A is carried out by comparing it with OpenFAST through the case study of a 5 MW wind turbine supported by the OC3-Hywind spar platform. The results show excellent agreements between F2A and OpenFAST in predicting dynamic responses of the blades, tower, platform and station-keeping system under both steady and turbulent winds combined with wave conditions. This implies that the simulation capabilities of FAST are well implemented within AQWA. Further advantages and capabilities of F2A in examining the dynamics of a FOWT are investigated via a case study of a multi-body platform concept connected by flexible elements. Some unique phenomena can only be observed from the results obtained using F2A as opposed to conventional tools. The results indicate that the newly-developed F2A coupling framework can be used for the analysis of FOWTs and it has been released to the public