Radiolyse α des solutions aqueuses d’acide nitrique et de plutonium

National audienc

Alpha radiolysis of nitric acid solutions with plutonium

International audienc

Radiation chemical behavior of aqueous butanal oxime solutions under alpha irradiation

International audienceContext Hydrazinium nitrate is a compound used in industry to avoid nitrous acid accumulation during the liquid-liquid separation of uranium and plutonium (PUREX). Now, hydrazinium nitrate is a CMR (Carcinogenic, Mutagenic, or toxic to Reproduction) compound and its use has to be reduced according to the European REACH directive of 2007. Moreover, hydrazinium nitrate is not extracted in the organic phase. Then it induces an accumulation of nitrous acid in this medium due to its partition between the two phases. It leads to an over-consumption of the Pu reducer, U(IV), due to the reoxidation of plutonium (III) to plutonium (IV) by HNO$_2$ in the organic phase. Numerous substitutes to hydrazinium nitrate have then been considered to find a compound which quickly reacts with HNO$_2$ and which can be partly extracted by TBP. The aim of this study is actually to investigate the behavior of these potential substitutes under irradiation. As a result of previous investigations, butanal oxime has been selected as potential substitute to hydrazinium nitrate in the PUREX process

Alpha radiolysis of nitric acid using the 68 MeV helions beam of the ARRONAX cyclotron

International audienc

Radiation chemical behavior of aqueous butanal oxime solutions irradiated with helium ion beams

International audienc

Alpha radiolysis of nitric acid and sodium nitrate with 4He2+ beam of 13.5 MeV energy

International audienc

Nephrol Dial Transplant

BACKGROUND: Several models have been proposed to predict kidney graft failure in adult recipients but none in younger recipients. Our objective was to propose a dynamic prediction model for graft failure in young kidney transplant recipients. METHODS: We included 793 kidney transplant recipients waitlisted before the age of 18 years who received a first kidney transplantation before the age of 21 years in France in 2002-13 and survived >90 days with a functioning graft. We used a Cox model including baseline predictors only (sex, age at transplant, primary kidney disease, dialysis duration, donor type and age, human leucocyte antigen matching, cytomegalovirus serostatus, cold ischaemia time and delayed graft function) and two joint models also accounting for post-transplant estimated glomerular filtration rate (eGFR) trajectory. Predictive performances were evaluated using a cross-validated area under the curve (AUC) and R2 curves. RESULTS: When predicting the risk of graft failure from any time within the first 7 years after paediatric kidney transplantation, the predictions for the following 3 or 5 years were accurate and much better with the joint models than with the Cox model (AUC ranged from 0.83 to 0.91 for the joint models versus 0.56 to 0.64 for the Cox model). CONCLUSION: Accounting for post-transplant eGFR trajectory strongly increased the accuracy of graft failure prediction in young kidney transplant recipients

Kidney Int

Socioeconomic status is an important determinant of health. Its impact on kidney transplantation outcome has been studied among adults but data in children are scarce, especially in Europe. Here, we investigate the association between the level of social deprivation (determined by the continuous score European Deprivation Index) and graft failure risk in pediatric kidney transplant recipients. All patients listed under 18 years of age who received a first kidney transplant between 2002 and 2014 in France were included. Of 1050 kidney transplant recipients (males 59%, median age at transplantation 13.2 years, preemptive transplantation 23%), 211 graft failures occurred within a median followup of 5.9 years. Thirty-seven percent of these patients belong to the most deprived quintile, suggesting that deprivation is more frequent in pediatric patients with end-stage kidney disease (ESKD) than in the general population. Five- and ten-year graft survival were 85% and 69%, respectively, in the most deprived quintile vs. 90% and 83%, respectively, in the least deprived quintile. At any time after transplantation, patients in the most deprived quintile had almost a two-fold higher hazard of graft failure compared with the least deprived quintile, after adjustment for age at renal replacement therapy, duration of dialysis, primary kidney disease, and rural/urban living environment (hazard ratio 1.99; 95% confidence interval 1.20-3.28). The hazard of graft failure did not differ significantly between girls and boys. Thus, our findings suggest a lower socioeconomic status is independently associated with poor graft outcome in pediatric kidney transplantation