New linear plasma devices in the trilateral euregio cluster for an integrated approach to plasma surface interactions in fusion reactors

New linear plasma devices are currently being constructed or planned in the Trilateral Euregio Cluster (TEC) to meet the challenges with respect to plasma surface interactions in DEMO and ITER: i) MAGNUM-PSI (FOM), a high particle and power flux device with super-conducting magnetic field coils which will reach ITER-like divertor conditions at high magnetic field, ii) the newly proposed linear plasma device JULE-PSI (FZJ), which will allow to expose toxic and neutron activated target samples to ITER-like fluences and ion energies including in vacuo analysis of neutron activated samples, and iii) the plasmatron VISION I. a compact plasma device which will be operated inside the tritium lab at SCK-CEN Mol, capable to investigate tritium plasmas and moderately activated wall materials. This contribution shows the capabilities of the new devices and their forerunner experiments (Pilot-PSI at FOM and PSI-2 Julich at FZJ) in view of the main objectives of the new TEC program on plasma surface interactions. (C) 2011 Forschungszentrum Julich, Institut fur Energieforschung-Plasmaphysik. Published by Elsevier B.V. All rights reserved

Particularités de l'effet de dose

Si on considère la "courbe de dilution" due à un additif, l'effet de dose d'un composé irradié peut se comprendre comme une addition d'interventions des divers produits de la radiolyse. Pour avoir un "effet de dose", les réactions "secondaires" doivent être possibles ("effet de température" et d'"intensité de dose"). L'irradiation d'un composé dissous simplifie les mécanismes complexes de la radiolyse et l'"effet de dose" si le soluté est un intercepteur efficace de radicaux. Toutefois, il faut éviter de commenter un "effet de dose" lorsque les produits étudiés ne sont pas les plus importants de la radiolyse. La simulation cinétique permet d’éviter ce type d'erreur

The Calcium-channel Blocker Nifedipine Fails To Inhibit Leukocyte Elastase Release During Cardiopulmonary Bypass

Circulating concentrations of leucocyte elastase were measured in 16 adult patients undergoing cardiopulmonary bypass (CPB) with a flat-sheet membrane oxygenator. Eight patients (Group I) received the calcium channel blocker nifedipine 9 mug.kg-1.h-1) during CPB. Eight patients (Group II) did not receive any calcium channel blocker during surgery and served as the control group. Elastase concentrations were measured at 7 time points: 2 before, 2 during, and 3 after CPB. The bypass procedure was associated with elevation in elastase concentrations (P < 0.001). Comparing to baseline values elastase concentrations were significantly elevated (P < 0.05) 60 min after the start of CPB and on all measurements done after CPB. Elastase concentrations correlated with the duration of CPB (rs = 0.76, P < 0.001), and were not influenced by nifedipine infusion as revealed by comparing the two groups. This study demonstrates moderate elastase release during CPB with a flat-sheet membrane oxygenator and fails to confirm inhibition of elastase release by nifedipine infusion during CPB

Lake Muzahi, Rwanda:limnological features and phytoplankton production

peer reviewedLake Muhazi, a small lake of Rwanda (East Africa) was studied from 1986 to 1990. A dramatic decrease of the catch of Oreochromis niloticus (350 T y-1 in the fifties vs 30 T y-1 in 1982) suggested a loss of productivity or overfishing. In the same period, other ecological changes occurred: the submerged macrophytes regressed and there was a decrease in Secchi depth (0.65 m in 1987 vs 1.5 m in the fifties). Compared to other lakes of the same area, the plankton production seemed low. The results of the present study characterize lake Muhazi as a shallow lake with a rather unstable diurnal stratification and with slight differences in mixing regime between its eastern, deepest part and its western, shallowest part. Secchi disk depth does not vary seasonally to a large extent. The water has a rather high mineral content (conductivity of about 500 μS cm-1 at 25 °C) and low concentrations of dissolved N and P, except in the hypolimnion, where NHinf4sup+ -N can be high. Two species, Microcystis aeruginosa and Ceratium hirundinella, account for most of the phytoplankton biomass, which is about 50-80 mg chlorophyll a m-2 in the euphotic zone, usually with little seasonal variation. Daily gross production estimates amount to about 6 to 9.5 g O2 m-2 d-1 with a significant difference between the two parts of the lake. Data on C:N and C:P ratio in the phytoplankton suggest that some N deficiency might occur in the eastern part. Moreover, the Zm:Zc ratio could also lead to rather low net production rates (0.21-0.25 d-1 for a mixed layer of 4 m) In conclusion, the primary production of lake Muhazi is medium for African lakes and the hypothesis that decreased planktonic production could account for a reduced fish production should be discarded. Whereas the present yield of the fishery is only 20 kg ha-1 y-1, the yield estimated from primary production ranges between 46 and 64 kg ha-1 y-1. This could be reached through proper management. Finally, some hypotheses are given to explain the ecological changes which occurred in the lake. © 1993 Kluwer Academic Publishers