Qualitative modelling and analysis of regulations in multi-cellular systems using Petri nets and topological collections

In this paper, we aim at modelling and analyzing the regulation processes in multi-cellular biological systems, in particular tissues. The modelling framework is based on interconnected logical regulatory networks a la Rene Thomas equipped with information about their spatial relationships. The semantics of such models is expressed through colored Petri nets to implement regulation rules, combined with topological collections to implement the spatial information. Some constraints are put on the the representation of spatial information in order to preserve the possibility of an enumerative and exhaustive state space exploration. This paper presents the modelling framework, its semantics, as well as a prototype implementation that allowed preliminary experimentation on some applications.Comment: In Proceedings MeCBIC 2010, arXiv:1011.005

Rpgrip1 is required for rod outer segment development and ciliary protein trafficking in zebrafish

The authors would like to thank the Royal Society of London, the National Eye Research Centre, the Visual Research Trust, Fight for Sight, the W.H. Ross Foundation, the Rosetrees Trust, and the Glasgow Children’s Hospital Charity for supporting this work. This work was also supported by the Deanship of Scientific Research at King Saud University for funding this research (Research Project) grant number ‘RGP – VPP – 219’.Mutations in the RPGR-interacting protein 1 (RPGRIP1) gene cause recessive Leber congenital amaurosis (LCA), juvenile retinitis pigmentosa (RP) and cone-rod dystrophy. RPGRIP1 interacts with other retinal disease-causing proteins and has been proposed to have a role in ciliary protein transport; however, its function remains elusive. Here, we describe a new zebrafish model carrying a nonsense mutation in the rpgrip1 gene. Rpgrip1homozygous mutants do not form rod outer segments and display mislocalization of rhodopsin, suggesting a role for RPGRIP1 in rhodopsin-bearing vesicle trafficking. Furthermore, Rab8, the key regulator of rhodopsin ciliary trafficking, was mislocalized in photoreceptor cells of rpgrip1 mutants. The degeneration of rod cells is early onset, followed by the death of cone cells. These phenotypes are similar to that observed in LCA and juvenile RP patients. Our data indicate RPGRIP1 is necessary for rod outer segment development through regulating ciliary protein trafficking. The rpgrip1 mutant zebrafish may provide a platform for developing therapeutic treatments for RP patients.Publisher PDFPeer reviewe

Effect of temperature and hydrogen exposure on the mechanical response of filled elastomers: A study on acrylonitrile butadiene rubbers filled with carbon black

International audienceFilled elastomers are widely used in components within the gas infrastructures. Currently, it is necessary to evaluate their suitability to harsh conditions of temperature and pressure required by the hydrogen applications. The effect of the environmental conditions on the material mechanical response (up to fracture) has been evaluated, by performing tests at different temperatures or under pressurized hydrogen, on three carbon black-filled acrylonitrile butadiene rubbers. With the increase of temperature, the fracture resistance resulted to decrease and the crack advancement rate increased. If the gas pressure applied during testing increases, the fracture toughness evaluated at the onset of unstable crack propagation increases while the crack advancement rate decreases. Some effects related to the gas type (hydrogen or nitrogen) were also observed. Moreover, if the material was previously exposed to pressurized hydrogen, no effects on the mechanical response were observed

Economie des entreprises: La méthode budgétaire appliquée à la gestion des exploitations

In order to simplify administrative work and to give it maximum efficienty it is necessary to show up the various items of expenses and receipts clearly and the margins which do not comply with reasonable objectives (exceptions) and also how great the gap is (disparity). The measurement of such "disparities" and the pointing out of "exceptions" by means of a permanent budgetary control are the most frequently used management "tools"

Economie des entreprises: La méthode budgétaire appliquée à la gestion des exploitations

[eng] The budgetary method applied to farm and agricultural cooperative management - In order to simplify administrative work and to give it maximum efficienty it is necessary to show up the various items of expenses and receipts clearly and the margins which do not comply with reasonable objectives (exceptions) and also how great the gap is (disparity). The measurement of such "disparities" and the pointing out of "exceptions" by means of a permanent budgetary control are the most frequently used management "tools". [fre] Pour simplifier le travail de gestion tout en lui donnant l'efficacité maximum, il faut mettre en évidence les postes (dépenses, recettes) et les marges qui ne suivent pas les objectifs « raisonnables » (exception), et indiquer de combien ils s'en écartent (écarts). La mesure des « écarts » et la mise en évidence des « exceptions » par le contrôle budgétaire permanent sont des outils de gestion de plus en plus employés.

« L’évaluation psychologique » en structure d’évaluation et traitement de la douleur chronique : une nouvelle figure de la paradoxalité ?

International audienc