Experimental and theoretical determination of low electron energy loss spectra of Ag and Ru.

We show the experimental and calculated q-dependent low energy loss electron energy loss spectrum of Ru and Ag. The spectra were calculated within the time-dependent density-functional theory including local-field effects. For Ag, the momentum transfer was parallel to the (110) direction. For Ru the three main directions (010), (110) and (001) were investigated. The agreement between theory and experiment is very good for Ag and for momentum transfers parallel to the (001) direction of Ru. For momentum transfers parallel to the in-plane directions (110) and (010) the agreement for Ru is not satisfactory, which could be attributed to relativistic effects or to strong localization of the 4d states of Ru.

Catalytic oxidation of ammonia on RuO2(110) surfaces: mechanism and selectivity.

The selective oxidation of ammonia to either N2 or NO on RuO2(110) single-crystal surfaces was investigated by a combination of vibrational spectroscopy (HREELS), thermal desorption spectroscopy (TDS) and steady-state rate measurements under continuous flow conditions. The stoichiometric RuO2(110) surface exposes coordinatively unsaturated (cus) Ru atoms onto which adsorption of NH3 (NH3-cus) or dissociative adsorption of oxygen (O-cus) may occur. In the absence of O-cus, ammonia desorbs completely thermally without any reaction. However, interaction between NH3-cus and O-cus starts already at 90 K by hydrogen abstraction and hydrogenation to OH-cus, leading eventually to N-cus and H2O. The N-cus species recombine either with each other to N2 or with neighboring O-cus leading to strongly held NO-cus which desorbs around 500 K. The latter reaction is favored by higher concentrations of O-cus. Under steady-state flow condition with constant NH3 partial pressure and varying O2 pressure, the rate for N2 formation takes off first, passes through a maximum and then decreases again, whereas that for NO production exhibits an S-shape and rises continuously. In this way at 530 K almost 100% selectivity for NO formation (with fairly high reaction probability for NH3) is reached.

62-W cw TEM(00) Nd:YAG laser side-pumped by fiber-coupled diode lasers.

We describe the laser performance and thermal properties of side-pumped Nd:YAG rod lasers that use ibercoupled diode lasers as pump sources. Utilizing a nearly homogeneous pump light profile, we realize an output power of more than 60 W in TEM(00) mode operation with optical-to-optical efficiencies of more than 25%. In multimode operation, optical slope efficiencies of more than 46% are observed.

Amplitude and frequency stability of a diode-pumped Nd:YAG laser operating at a single-frequency continuous-wave output power of 20 W.

Amplitude and frequency noise of an injection-locked diode-pumped Nd:YAG ring laser operating at a singlefrequency output power of 20 W cw are investigated. This laser system will be used as a light source for an interferometric gravitational-wave detector.

300-W cw diode-laser side-pumped Nd:YAG rod laser.

We report on the laser performance and power scaling properties of diode-laser side-pumped Nd:YAG rod lasers operating at high cw output powers. Applying a pump power of 1100 W cw in a ninefold pump geometry, we obtain an output power of more than 300 W in multimode operation. For a comparable pump scheme an output power of more than 45 W in TEM(00) mode operation is realized with an optical-to-optical efficiency of more than 11%.

[Paroxetine in the treatment of depression in geriatric patients--a double-blind comparative study with fluoxetine]. / Paroxetin in der Depressionsbehandlung geriatrischer Patienten--eine doppelblinde Vergleichsstudie mit Fluoxetin.

A 6-week double-blind, parallel group study compared paroxetine and fluoxetine in 106 depressed geriatric inpatients (aged 65 to 85 years). Patients presenting acutely with major depressive episode DSM-III-R 296.2 (HAMD > 18 on 21 item scale) were randomized to receive paroxetine (20-40 mg, n = 54) or fluoxetine (20-60 mg, n = 52) following a 3-7 day washout. Primary criteria was the reduction of Hamilton Depression Rating Scale Score (HAMD). Furthermore Montgomery-Asberg Depression Rating Scale (MADRS) and the Clinical Global Impression Scale (CGI) were used. Cognitive functions were assessed with the Mini-Mental-State Examination (MMSE) and the Sandoz Clinical Assessment Geriatric Scale (SCAG). The results showed a comparable reduction in the depression rating scales between the two treatment groups after 6 weeks. However, there was a statistically significant difference (p < 0.05) in HAMD, MADRS, SCAG, MMSE and cognitive subscales of HAMD and SCAG at week 3 in favour of paroxetine, which even was seen after 6 weeks in the SCAG. There were no significant differences between the treatment groups and the number of adverse events reported or in overall tolerability.

A double-blind study of paroxetine compared with fluoxetine in geriatric patients with major depression.

A 6-week, double-blind, parallel group study compared the efficacy and tolerability of paroxetine and fluoxetine in 106 depressed geriatric outpatients (age, > or = 65 years). Patients with an acute major depressive episode were randomized to receive either paroxetine (20 to 40 mg; N = 54) or fluoxetine (20 to 60 mg; N = 52) after a 3- to 7-day washout. Efficacy evaluations at weeks 1, 3, and 6 used the 21-item Hamilton Rating Scale for Depression (HAM-D). Cognitive function was assessed by use of the Mini-Mental State Examination (MMSE) and the Sandoz Clinical Assessment Geriatric Scale (SCAG). Tolerability was assessed by response to a nonleading question concerning adverse events. There were no significant differences between treatments at week 6 on the HAM-D total, change from baseline. However, there was a statistically significant difference (p < 0.05) at week 3 in favor of paroxetine. Results from the MMSE and SCAG showed that, during treatment, patients in the paroxetine group were characterized by greater improvement in cognitive function than were those in the fluoxetine group. This result was statistically significant at week 3 for both scales (p < 0.05). Adverse events occurred most frequently within the gastrointestinal and nervous systems for both drugs, with no significant differences between treatments.