Probing Strong-Field QED with Doppler-Boosted Petawatt-Class Lasers.

We propose a scheme to explore regimes of strong-field quantum electrodynamics (SF QED) otherwise unattainable with the currently available laser technology. The scheme relies on relativistic plasma mirrors curved by radiation pressure to boost the intensity of petawatt-class laser pulses by Doppler effect and focus them to extreme field intensities. We show that very clear SF QED signatures could be observed by placing a secondary target where the boosted beam is focused.

Relativistic Acceleration of Electrons Injected by a Plasma Mirror into a Radially Polarized Laser Beam.

We propose a method to generate femtosecond, relativistic, and high-charge electron bunches using few-cycle and tightly focused radially polarized laser pulses. In this scheme, the incident laser pulse reflects off an overdense plasma that injects electrons into the reflected pulse. Particle-in-cell simulations show that the plasma injects electrons ideally, resulting in a dramatic increase of charge and energy of the accelerated electron bunch in comparison to previous methods. This method can be used to generate femtosecond pC bunches with energies in the 1-10 MeV range using realistic laser parameters corresponding to current kHz laser systems.

[Trimetazidine prevents ischemia-reperfusion injury in hepatic surgery under vascular clamping]. / La trimétazidine prévient les lésions d'ischémie-reperfusion de la chirurgie hépatique sous clampage vasculaire.

Clamping the hepatic pedicle (or Pringle's manoeuvre) is frequently used to reduce blood loss during liver surgery. This induces a normothermic ischaemia of the overall liver. In this study we have investigated the anti-ischaemic effect of trimetazidine during surgery on hydatid cysts of the liver requiring vascular clamping of the hepatic pedicle. Seventy-six hepatic pericystectomies were performed under a 40 min normothermic ischaemia. Two randomized groups including 38 patients each received daily either trimetazidine (80 mg/kg, group 1) or placebo (group 2) for 5 days before surgery. The effect of trimetazidine was evaluated on different parameters, the macroscopic appearance of the tissue, the ATP content in liver biopsies obtained before and after 15, 30 and 60 min reperfusion, the activity of the aminotransferase in the plasma and the plasma concentrations of reduced and oxidized gluthatione. No mortality was observed. The duration of hospital stay was reduced for patients treated with trimetazidine (8 +/- 1 days compared with 11 +/- 1.5 days for patients in group 2; p < 0.05). Morbidity rate was lower in group 1 (11 per cent) than in group 2 (18.5 per cent) but the decrease was not significant. Trimetazidine treatment reduced cytolysis (p < 0.05 on day 1, day 3, day 5), increased liver ATP content and limited the increase of reduced and oxidized gluthatione in the plasma during reperfusion. These results suggest that trimetazidine alleviates ischaemia-reperfusion injury during liver surgery and may allow extension of the ischaemic period without damage to the liver.