Status and commissioning-results of BESSY II
The new Storage Ring BESSY II in Berlin Germany is a dedicated third generation synchrotron radiation source for the VUV and soft X-ray spectral range. On April 22/sup nd/, 1998 a 1.7 GeV electron beam was stored for the first time. Despite a relatively short time for commissioning of the synchrotron radiation source, the milestones were met as scheduled. Accelerator parameters that determine the quality of the synchrotron radiation are as designed or the design goals were even exceeded. The only parameter that is still not according to design is the beam lifetime, as the baking of the vacuum system is not completed yet. The regular scientific program started according to plan in January 1999 with experiments. The front-end for 22 additional beamlines are installed and scheduled for use before the end of next year. Thus required shutdown periods will also be used to install additional hardware to improve the performance of the ring.
CONTROL SYSTEM RELIABILITY REQUIRES CAREFUL SOFTWARE INSTALLATION PROCEDURES
The demands on availability and reliability of the control system reflects the stability needed by accelerators in production. On the other hand the system is continuously developed and new features have to be included and adapted. With growing complexity of the system testing for unforeseen side effects becomes increasingly difficult. Frequently control access to pieces of equipment essential for the operation is necessary. Maintenance periods suited for installations are mostly extremely short. This paper describes the release control system and the installation stages used at BESSY to provide a high level of control system transparency and stability.
Effect of a new inhibitor of cholesterol biosynthesis (AY 9944) on serum and tissue sterols in the rat.
AY 9944 is a novel inhibitor of cholesterol biosynthesis which appears to act on the Delta 7-reductase enzyme, interfering with the conversion of 7-dehydrocholesterol to cholesterol. In all tissues studied, with the exception of the lens, there was a reduction in cholesterol and a marked accumulation of 7-dehydrocholesterol. Isotope studies showed a reduced uptake of acetate into cholesterol, and an increased uptake into 7-dehydrocholesterol, in various tissues in vivo and by skin samples in vitro. There was no apparent accumulation of lanosterol or of the methostenols in the rat skin.