Estimation de la dose efficace au poste de travail : intérêt de disposer d'un moyen de mesure adapté

Les valeurs limites annuelles d’exposition de l’organisme entier des travailleurs et du public sont définies à l’aide de la dose efficace E. Les dosimètres individuels portés par les travailleurs évaluent un estimateur de cette grandeur de protection : l’équivalent de dose individuel. Cet article présente les deux méthodes de calcul des équivalents de dose et de la dose efficace ainsi que les résultats obtenus dans un champ mixte neutronique-photonique auprès d’une boîte à gants. Les équivalents de dose calculés pour ce poste de travail dépendent des hypothèses de calcul. Estimer la dose efficace à partir de ces résultats se révèle de ce fait délicat. Cette étude démontre ainsi l’intérêt de disposer d’un moyen de mesure de la dose efficace

Anthropomorphic phantom for effective dose measurements: Feasibility numerical study and presentation of the detector development

This paper presents the current state of a project from the laboratory of ionizing radiation dosimetry of the IRSN (France) concerning the development of an instrumented anthropomorphic phantom for the direct measurement of the effective dose. Contrary to other applications fields where anthropomorphic phantoms are currently used (radiotherapy dose control or spatial studies), the main challenge of this project is to develop small detectors to place inside the phantom sensible to the low-dose rates found at workplaces. A numerical study for photon irradiation fields has proved the feasibility of such an instrument and has determined the positions of the detectors for each organ in order to correctly evaluate the effective dose. Some results of this numerical study are presented here as well as a preliminary schematic description of the prototype detector. © 2008 Elsevier Ltd. All rights reserved

Complex mechanisms for c-fos and c-jun degradation

c-fos and c-jun proto-oncogenes have originally been found in mutated forms in murine and avian oncogenic retroviruses. They both define multigenic families of transcription factors. Both c-jun and c-fos proteins are metabolically unstable. In vivo and in vitro work by various groups suggests that multiple proteolytic machineries, including the lysosomes, the proteasome and the ubiquitous calpains, may participate in the destruction of c-fos and c-jun. The relative contribution of each pathway is far from being known and it cannot be excluded that it varies according to the cell context and/or the physiological conditions. It has been demonstrated that, in certain occurrences, the degradation of both c-fos and c-jun by the proteasome in vivo involves the ubiquitin pathway. However, the possibility that proteasomal degradation can also occur in a manner independent of the E1 enzyme of the ubiquitin cycle remains an open issue

Complex mechanisms for c-fos and c-jun degradation

c-fos and c-jun proto-oncogenes have originally been found in mutated forms in murine and avian oncogenic retroviruses. They both define multigenic families of transcription factors. Both c-jun and c-fos proteins are metabolically unstable. In vivo and in vitro work by various groups suggests that multiple proteolytic machineries, including the lysosomes, the proteasome and the ubiquitous calpains, may participate in the destruction of c-fos and c-jun. The relative contribution of each pathway is far from being known and it cannot be excluded that it varies according to the cell context and/or the physiological conditions. It has been demonstrated that, in certain occurrences, the degradation of both c-fos and c-jun by the proteasome in vivo involves the ubiquitin pathway. However, the possibility that proteasomal degradation can also occur in a manner independent of the E1 enzyme of the ubiquitin cycle remains an open issue

Etude de la fertilité chez le bouc : analyse métabolique par RMN

International audienc

Determination by echography of uterine changes around puberty in gilts and evaluation of a diagnosis of puberty

International audienc