Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Isotopic fractionation of tritium is a highly relevant issue in radiation protection and requires certain radioecological considerations. Sound evaluation of this factor is indeed necessary to determine whether environmental compartments are enriched/depleted in tritium or if tritium is, on the contrary, isotopically well-distributed in a given system. The ubiquity of tritium and the standard analytical methods used to assay it may induce biases in both the measurement and the signification that is accorded to the so-called fractionation: based on an exhaustive review of the literature, we show how, sometimes large deviations may appear. It is shown that when comparing the non-exchangeable fraction of organically bound tritium (neOBT) to another fraction of tritium (e.g. tritiated water) the preparation of samples and the measurement of neOBT reported frequently led to underestimation of the ratio of tritium to hydrogen (T/H) in the non-exchangeable compartment by a factor of 5 % to 50 %. In the present study, corrections are proposed for most of the biological matrices studied so far. Nevertheless, the values of isotopic fractionation reported in the literature remain difficult to compare with each other, especially since the physical quantities and units often vary between authors. Some improvements are proposed to better define what should encompass the concepts of exchangeable and non-exchangeable fractions.
ISSN: 0160-4120

hal-01117744
https://hal.archives-ouvertes.fr/hal-01117744
https://hal.archives-ouvertes.fr/hal-01117744/document
https://hal.archives-ouvertes.fr/hal-01117744/file/Article%20review%20discrimination%20isotopique-envoy%C3%A9.pdf
DOI : 10.1016/j.envint.2013.12.020

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
11 4 : CEA/HC 12 13 Corresponding author: 14 pierre.legoff@cea.fr -+333 80 23 40 00 -+333 80 23 52 09 15 16 Abstract 17 As one of the three natural isotopes of hydrogen, tritium is ubiquitous and might potentially 18 be present in any water or organic molecule that constitutes a biological matrix. Milk is one of 19 the most frequently monitored foodstuffs in the vicinity of chronic release of radionuclides, as 20 it is a very common product and also because it integrates deposition on large areas of grass at 21 a local scale. Different parameters have been studied to assess their impact on the reliability 22 of tritium measurements. The volume of the sample, the technique used to extract the water 23 and the level of dehydration modulate the results but in different ways: dispersion of results, 24 under-or overestimation of the tritium activity. The influence of sample storage and 25 preparation has also been investigated. Methodological improvements of tritium 26 measurements in the free water of milk are proposed. 27 28
ISSN: 0265-931X

hal-01117741
https://hal.archives-ouvertes.fr/hal-01117741
https://hal.archives-ouvertes.fr/hal-01117741/document
https://hal.archives-ouvertes.fr/hal-01117741/file/Tritium%20in%20the%20free%20water%20of%20milk-FINAL.pdf
DOI : 10.1016/j.jenvrad.2013.09.006

Éditeur(s) : Paris : éditions Duchartre et Van Buggenhoudt
Extrait de : Les frères de La Coste, Flibustiers et Corsaires (p. 307)
Résumé : Abordage du Triton par le bateau Corsaire le Hasard (ex-Cartier) commandé par Robert Surcouf.

Permalien : http://www.manioc.org/images/FCL18014-0335i1
FCL18014-0335i1

Éditeur(s) : HAL CCSD EDP Sciences
Résumé : We propose and we justify a Monte-Carlo algorithm which solves a spatially homogeneous kinetic equation of Boltzmann type that models the fusion reaction between a deuterium ion and a tritium ion, and giving an α particle and a neutron. The proposed algorithm is validated with the use of explicit solutions of the kinetic model obtained by replacing the fusion cross-section by a Maxwellian cross section.
ISSN: 1270-900X

hal-00689821
https://hal.archives-ouvertes.fr/hal-00689821
https://hal.archives-ouvertes.fr/hal-00689821/document
https://hal.archives-ouvertes.fr/hal-00689821/file/proc_versionHAL.pdf

Éditeur(s) : HAL CCSD American Chemical Society
Résumé : International audience
The present study is a contribution to the "neXt50 challenge", a coordinated effort across C-HPP teams to identify the SO most tractable missing proteins (MPs) on each chromosome. We report the targeted search of 38 theoretically detectable MPs from chromosomes 2 and 14 in Triton X-100 soluble and insoluble sperm fractions from a total of 15 healthy donors. A targeted mass spectrometry-based strategy consisting of the development of LC-PRM assays (with heavy labeled synthetic peptides) targeting 92 proteotypic peptides of the 38 selected MPs was used. Out of the 38 selected MPs, 12 were identified with two or more peptides and 3 with one peptide after extensive SDS-PAGE fractionation of the two samples and with overall low-intensity signals. The PRM data are available via ProteomeXchange in PASSEL (PASS01013). Further validation by immunohistochemistry on human testes sections and cytochemistry on sperm smears was performed for eight MPs with antibodies available from the Human Protein Atlas. Deep analysis of human sperm still allows the validation of MPs and therefore contributes to the C-HPP worldwide effort. We anticipate that our results will be of interest to the reproductive biology community because an in-depth analysis of these MPs may identify potential new candidates in the context of human idiopathic infertilities.
ISSN: 1535-3893

hal-01681656
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01681656
DOI : 10.1021/acs.jproteome.7b00374