Laser wakefield acceleration with mid-IR laser pulses.

We report on, to the best of our knowledge, the first results of laser plasma wakefield acceleration driven by ultrashort mid-infrared (IR) laser pulses (λ=3.9 µm, 100 fs, 0.25 TW), which enable near- and above-critical density interactions with moderate-density gas jets. Relativistic electron acceleration up to ∼12 MeV occurs when the jet width exceeds the threshold scale length for relativistic self-focusing. We present scaling trends in the accelerated beam profiles, charge, and spectra, which are supported by particle-in-cell simulations and time-resolved images of the interaction. For similarly scaled conditions, we observe significant increases in the accelerated charge, compared to previous experiments with near-infrared (λ=800 nm) pulses.

Filamentation of mid-IR pulses in ambient air in the vicinity of molecular resonances.

Properties of filaments ignited by multi-millijoule, 90 fs mid-infrared pulses centered at 3.9 µm are examined experimentally by monitoring plasma density, losses, spectral dynamics and beam profile evolution at different focusing strengths. By changing from strong (f=0.25 m) to loose (f=7 m) focusing, we observe a shift from plasma-assisted filamentation to filaments with low plasma density. In the latter case, filamentation manifests itself by beam self-symmetrization and spatial self-channeling. Spectral dynamics in the case of loose focusing is dominated by the nonlinear Raman frequency downshift, which leads to the overlap with the CO2 resonance in the vicinity of 4.2 µm. The dynamic CO2 absorption in the case of 3.9 µm filaments with their low plasma content is the main mechanism of energy losses and, either alone or together with other nonlinear processes, contributes to the arrest of intensity.

[Orthotopic heart transplantation--experiences at the University Surgical Clinic II in Vienna (status: June 1986)]. / Die orthotope Herztransplantation--Erfahrungen an der II. Chirurgischen Universitätsklinik in Wien (Stand: Juni 1986).

Since 1984 27 heart transplantations (HTX) were carried out in 25 patients at the 2nd Department of Surgery, University of Vienna. The classic orthotopic technique of Lower and Shumway was used in all cases. Routine immunosuppression consisted of azathioprine and cyclosporin-A. In order to treat the main complications successfully, i.e. rejection and infections, we were compelled to establish an extensive follow up regimen. The early recognition of acute rejection was based on the findings obtained by cutaneous as well as epicardial ECG leads, in conjunction with cytoimmunological monitoring on the basis of RIA measurements of the serum levels of Neopterin and gamma-Interferon. Furthermore, we recorded some parameters of ventricular performance, such as the isovolumetric relaxation time and the radiologically measured heart volume. An endomyocardial biopsy was carried out to secure the diagnosis. Pulsed doses of methylprednisolone were used for the treatment of rejection, facultatively combined with ATG in the absence of improvements. Infections were pinpointed by comprehensive serum tests and various blood, sputum and urine cultures. The management consisted of treatment with the requisite antibiotics. Of 25 primarily transplanted patients 15 patients are still alive. 5 persons, amongst them 2 children, have survived already for more than 1 year. 6 patients died at an early stage. In 3 cases the cause of death was intractable infection. In 1 case multi-organ failure occurred and 1 patient died due to acute organ failure. 4 patients died at a late stage and acute severe rejection was responsible in all these cases.(ABSTRACT TRUNCATED AT 250 WORDS)

[Psychological stress factors in intensive care]. / Psychische Stressfaktoren in der Intensivmedizin.

In three intensive care units we looked into the question whether there are environmental situations somewhat equally stressful for the patients using 52 stress items designed by ourselves for the study. The patients had to place the various items in a sequence of increasing annoyance just one day after discharge from the intensive care unit. The most annoying factor for all patients, almost independent of sex and diagnosis, was the item "lack of information and communication". The item "noise and unrest caused by the daily routine and the nursing staff of the intensive care unit" was put in the first place by patients aged more than 50 years. Helplessness and physical impairment are the most annoying factors reported by the ventilated patients. The item "dependence on technical devices" (e.g. ventilators, dialyzer etc.) was surprisingly quoted low by our patients. We conclude that a human orientated intensive care medicine approach should be developed. Further investigations concerning psychical care and help should be performed.