Crystal field analysis of Pm3+^{3+} (4f4)andSm^{f4}) and Sm^{3+}(4 (4^{f5}) and lattice location studies of 147^{147}Nd and 147^{147}Pm in w-AlN

We report a detailed crystal field analysis of Pm3+ and Sm3+ as well as lattice location studies of 147Pm and 147Nd in 2H-aluminum nitride (w-AlN). The isotopes of mass 147 were produced by nuclear fission and implanted at an energy of 60 keV. The decay chain of interest in this work is 147Nd→147Pm→147Sm (stable). Lattice location studies applying the emission channeling technique were carried out using the β− particles and conversion electrons emitted in the radioactive decay of 147Nd→147Pm. The samples were investigated as implanted, and also they were investigated after annealing to temperatures of 873 K as well as 1373 K. The main fraction of about 60% of both 147Pm as well as 147Nd atoms was located on substitutional Al sites in the AlN lattice; the remainder of the ions were located randomly within the AlN lattice. Following radioactive decay of 147Nd, the cathodoluminescence spectra of Pm3+ and Sm3+ were obtained between 500 nm and 1050 nm at sample temperatures between 12 K and 300 K. High-resolution emission spectra, representing intra-4f electron transitions, were analyzed to establish the crystal-field splitting of the energy levels of Sm3+ (4f5) and Pm3+ (4f4) in cationic sites having C3v symmetry in the AlN lattice. Using crystal-field splitting models, we obtained a rms deviation of 6 cm−1 between 31 calculated-to-experimental energy (Stark) levels for Sm3+ in AlN. The results are similar to those reported for Sm3+ implanted into GaN. Using a set of crystal-field splitting parameters Bnm, for Pm3+ derived from the present Sm3+ analysis, we calculated the splitting for the 5F1, 5I4, and 5I5 multiplet manifolds in Pm3+ and obtained good agreement between the calculated and the experimental Stark levels. Temperature-dependent lifetime measurements are also reported for the emitting levels 4F5∕2 (Sm3+) and 5F1 (Pm3+)

Catalytic Reactivation of Industrial Oxygen Depolarized Cathodes by in situ Generation of Atomic Hydrogen

Electrocatalytically active materials on the industrial as well as on the laboratory scale may suffer from chemical instability during operation, air exposure, or storage in the electrolyte. A strategy to recover the loss of electrocatalytic activity is presented. Oxygen depolarized cathodes ODC , analogous to those that are utilized in industrial brine electrolysis, are analyzed the catalytic activity of the electrodes upon storage 4 weeks under industrial process conditions 30 wt NaOH, without operation diminishes. This phenomenon occurs as a consequence of surface oxidation and pore blockage, as revealed by scanning electron microscopy, focused ion beam milling, X ray photoelectron spectroscopy, and Raman spectroscopy. Potentiodynamic cycling of the oxidized electrodes to highly reductive potentials and the formation of nascent hydrogen re reduces the electrode material, ultimately recovering the former catalytic activit

Intravenous NPA for the treatment of infarcting myocardium early: InTIME-II, a double-blind comparison on of single-bolus lanoteplase vs accelerated alteplase for the treatment of patients with acute myocardial infarction

Aims to compare the efficacy and safety of lanoteplase, a single-bolus thrombolytic drug derived from alteplase tissue plasminogen activator, with the established accelerated alteplase regimen in patients presenting within 6 h of onset of ST elevation acute myocardial infarction. Methods and Results 15 078 patients were recruited from 855 hospitals worldwide and randomized in a 2:1 ratio to receive either lanoteplase 120 KU. kg-1 as a single intravenous bolus, or up to 100 mg accelerated alteplase given over 90 min. The primary end-point was all-cause mortality at 30 days and the hypothesis was that the two treatments would be equivalent. By 30 days, 6.61% of alteplase-treated patients and 6.75% lanoteplase-treated patients had died (relative risk 1.02). Total stroke occurred in 1.53% alteplase- and 1.87% lanoteplase-treated patients (ns); haemorrhagic stroke rates were 0.64% alteplase and 1.12% lanoteplase (P=0.004). The net clinical deficit of 30-day death or non-fatal disabling stroke was 7.0% and 7.2%, respectively. By 6 months, 8.8% of alteplase-treated patients and 8.7% of lanoteplase-treated patients had died. Conclusion Single-bolus weight-adjusted lanoteplase is an effective thrombolytic agent, equivalent to alteplase in terms of its impact on survival and with a comparable risk-benefit profile. The single-bolus regimen should shorten symptoms to treatment times and be especially convenient for emergency department or out-of-hospital administration. (C) 2000 The European Society of Cardiology