[en] Brown Boveri have developed new watertight ultraviolet irradiation units for surface sterilization. Their main application is in packing techniques in the foodstuffs and pharmaceutical industries. This article describes the construction, germicidal effect, and applications of these irradiation units. (Auth.)

[en] This article presents thoughts on how electricity generation in Switzerland can develop. A short, general review of the political and market situations is presented and various means of electricity generation, including geothermal, combined heat and power, hydropower and combined-cycle power stations are discussed. Also, the role of Switzerland in the European electricity network is looked at. Economical and ecological requirements placed on future generation facilities are examined. Combined-cycle power stations together with heat-pumps are proposed as a way of producing net-CO₂-free electricity

[en] High-speed d.c. switches for blocking-voltages of up to 120 kV have been built with Brown Boveri high-power tetrodes for nuclear fusion research. These switches also act as regulators capable of dissipating steady-state power losses of 1000 kW and above. (Auth.)

No abstract available

[en] Estimation of the annual and cumulated amount of radioactive wastes from nuclear power stations in the FRG until the year 1990. Present practice and thoughts on the future practice of waste management. (AK)

[en] Analysis of the frequency and significance of small focal liver lesions (≤ 2 cm) detected on MRI in the presence or absence of a history of malignancy. Methods: 628 MRI examinations of the liver performed during 1994 - 1996 were evaluated. The inclusion criterion into the study was the detection of a focal liver lesion with a size ≤ 2 cm. The frequency, the size, the diagnostic proof, and the differential diagnosis of the focal liver lesions were analysed with regard to the patients history of a known malignant tumor. Results: Overall, 179 of the 628 patients (28.5%) had focal liver lesions ≤ 2 cm (n = 338). 58.9% of the lesions could be classified based upon follow-up studies by ultrasound, CT or MRI, or by biopsy. The remaining 41.1% of the lesions could not be classified due to the absence of follow-up examinations. 57.3% of all proven lesions were benign and 42.7% were malignant. A history of a malignant tumor was present in 76.7% of all patients with small liver lesions; however, lesions were benign in these patients in 50.6% of the cases. In patients with no known history of a malignancy, 75% of the lesions were benign and 25% were malignant. However, these malignant lesions were in 10/11 cases hepatocellular carcinomas in patients with liver cirrhosis. (orig.)

[en] Purpose: Budd-Chiari syndrome is a fairly uncommon disease in Europe. This often leads to its late diagnosis. The syndrome is characterised by portal hypertension and splanchnic congestion due to obstruction of hepatic venous outflow. This paper describes the treatment of three patients with Budd-Chiari syndrome by interventional therapeutic techniques and discusses alternative treatment modalities. Patients and Methods: The first patient presented with veno-occlusive disease and was treated by the placement of a transjugular intrahepatic portosystemic stentshunt. The second patient showed an occlusion of the major hepatic veins. After percutaneous recanalisation, a stent was placed in the right hepatic vein which remained patent. The third patient had a membranous obstruction of the right hepatic vein which was treated by percutaneous balloon dilatation. Results: In all patients the clinical symptoms resolved completely after treatment and no complications were encountered. Conclusions: The authors conclude that interventional therapeutic techniques offer a wide variety of possibilities for the treatment of patients with Budd-Chiari syndrome and are safe, effective and relatively inexpensive. However, further studies are required to assess the long-term results and survival rates of these patients. (orig.)

[en] PROMETHEUS is a Fortran IV program system for investigation of anharmonic thermal vibrations in crystals, using elastic X-ray or neutron data. Three different anharmonic-temperature-factor equations can be used, one of them up to sixth-order terms. The corresponding probability densities and mean effective atomic potentials can be calculated. Programs for correction of isotropic thermal diffuse scattering and of isotropic and anisotropic extinction are included. Fast averaging of symmetrically equivalent reflections combined with extended reflection statistics is possible. Calculations of Fourier syntheses and their errors and of Patterson functions can be carried out and the corresponding contour maps can be plotted. (Auth.)

[en] Purpose: The increased T1 relaxation times at 3.0 Tesla lead to a reduced T1 contrast, requiring adaptation of imaging protocols for high magnetic fields. This prospective study assesses the performance of three techniques for T1-weighted imaging (T1w) at 3.0 T with regard to gray-white differentiation and contrast-to-noise-ratio (CNR). Materials and Methods: Thirty-one patients were examined at a 3.0 T system with axial T1 w inversion recovery (IR), spin-echo (SE) and gradient echo (GE) sequences and after contrast enhancement (CE) with CE-SE and CE-GE sequences. For qualitative analysis, the images were ranked with regard to artifacts, gray-white differentiation, image noise and overall diagnostic quality. For quantitative analysis, the CNR was calculated, and cortex and basal ganglia were compared with the white matter. Results: In the qualitative analysis, IR was judged superior to SE and GE for gray-white differentiation, image noise and overall diagnostic quality, but inferior to the GE sequence with regard to artifacts. CE-GE proved superior to CE-SE in all categories. In the quantitative analysis, CNR of the based ganglia was highest for IR, followed by GE and SE. For the CNR of the cortex, no significant difference was found between IR (16.9) and GE (15.4) but both were superior to the SE (9.4). The CNR of the cortex was significantly higher for CE-GE compared to CE-SE (12.7 vs. 7.6, p<0.001), but the CNR of the basal ganglia was not significantly different. Conclusion: For unenhanced T1w imaging at 3.0 T, the IR technique is, despite increased artifacts, the method of choice due to its superior gray-white differentiation and best overall image quality. For CE-studies, GE sequences are recommended. For cerebral imaging, SE sequences give unsatisfactory results at 3.0 T. (orig.)

[en] Purpose: To determine the value of a dynamic Gd-enhanced ultrafast T₁-weighted 3D-turbo-gradient-echo sequence (3D-TFE) in the detection and characterization of focal liver lesions. Results: On 3D-TFE images more lesions (107/124) were identified than on T₁-weighted SE (101/124) and T₁-weighted FFE images (106/124), but less compared to T₂-weighted TSE SPIR images (115/124). The 3D-TFE-sequence provided additional information in 65/107 (61%) detected lesions by delineating the dynamic enhancement pattern, most valuable in patients with HCCs in 90%. Conclusions: On dynamic 3D-TFE images more lesions could be depicted than on conventional T₁-weighted SE and T₁-weighted FFE images. Visualization of the dynamic enhancement pattern provided additional information for tumor characterization in 61% of the detected lesions on the 3D-TFE images. (orig./AJ)