Efficient XeF (C->A) laser Excited by a Coaxial Electron Beam at Intermediate Pumping Rates

Experiments carried out with an electron-beam apparatus that produced pump pulses with an intermediate pulse length of about 174 ns (FWHM) and a power-deposition rate on the order of 1 MW/cm3 are described. The authors present initial measurements with gas mixtures in which part of the Ar is replaced by Ne as a buffer gas. The lower stopping power of Ne can be compensated for by using a higher gas pressure because the system presented can be pressurized to a total gas pressure of 10 bar. It was found in earlier experiments with other excimers (ArF,KrF) that the variation of the buffer gas may have important effects on the optimum pressure regime total output energy, and kinetics. Useful information can be gained for discharge-excited systems, although the ionic channel dominates the electron-beam excitation kinetic

Thiazolides as novel antiviral agents. 1. Inhibition of hepatitis B virus replication

We report the syntheses and activities of a wide range of thiazolides [viz., 2-hydroxyaroyl-N-(thiazol-2-yl)amides] against hepatitis B virus replication, with QSAR analysis of our results. The prototypical thiazolide, nitazoxanide [2-hydroxybenzoyl-N-(5-nitrothiazol-2-yl)amide, NTZ] 1 is a broad spectrum antiinfective agent effective against anaerobic bacteria, viruses, and parasites. By contrast, 2-hydroxybenzoyl-N-(5-chlorothiazol-2-yl)amide 3 is a novel, potent, and selective inhibitor of hepatitis B replication (EC50 = 0.33 μm) but is inactive against anaerobes. Several 4'- and 5'-substituted thiazolides show good activity against HBV; by contrast, some related salicyloylanilides show a narrower spectrum of activity. The ADME properties of 3 are similar to 1; viz., the O-acetate is an effective prodrug, and the O-aryl glucuronide is a major metabolite. The QSAR study shows a good correlation of observed EC90 for intracellular virions with thiazolide structural parameters. Finally we discuss the mechanism of action of thiazolides in relation to the present results