Analysis of Gas-Phase Clusters Made from Laser-Vaporized Icosahedral Al−Pd−Mn
An icosahedral Al-Pd-Mn quasicrystal sample is laser vaporized to form metal clusters by gas aggregation. The clusters are subsequently laser ionized and mass analyzed in a time-of-flight mass spectrometer. The mass spectra show cluster compositions which are qualitatively similar to that of the sample. This is consistent with a kinetically controlled cluster growth process. Cluster thermodynamic stability is probed by multiphoton ionization/fragmentation, which induces primarily Al and Mn loss. The resulting spectra are composed of a series of Pd-rich Al-Pd clusters. The average cluster composition is 60 (′1)% Pd. This composition is close to a known eutectic in the Al-Pd system. When manganese is seen on these clusters, it is always in units of Mn 3 . These results are discussed in terms of relative binding strengths in the Al-Pd-Mn alloy system.
Ultrashort pulsed laser vaporisation of icosahedral Al Pd Mn
Abstract In this work, Al 70 Pd 20 Mn 10 quasicrystalline targets were evaporated by a doubled Nd:glass laser with a pulse duration of 250 fs. The produced plasma has been analysed by time of flight mass spectrometry, optical emission spectroscopy and fast imaging. The results indicate that the plume is more complex as compared to other quasicrystalline systems with the presence of quite large clusters and with a higher ionisation degree. The analyses on the deposited films indicate that the vaporisation is not congruent.
Multiple-dose pharmacokinetics of moxisylyte after oral administration to healthy volunteers.
The pharmacokinetics of moxisylyte in plasma and urine was investigated after oral administration. Twelve subjects were treated orally, twice daily with 240 mg of the drug for 6 days; on day 7, the subjects received a last dose of 240 mg of moxisylyte. Moxisylyte was assayed in plasma and urine by a specific HPLC method with fluorimetric detection. Moxisylyte was absorbed rapidly and changed to its metabolites immediately after drug administration; unchanged moxisylyte was not found in plasma. Two metabolites were found in plasma and urine: conjugated desacetylmoxisylyte (DAM) and the conjugate of desmethylated DAM (MDAM). The pharmacokinetic parameters determined after the first oral administration were not modified on multiple dosing. The apparent elimination half-lives of conjugated DAM and MDAM were 2.3 and 3.5 h, respectively. Elimination of these two metabolites in urine averaged 50 and 10%, respectively.