Switching strategies for antipsychotic monotherapy in schizophrenia: a multi-center cohort study of aripiprazole.

RATIONALE: Changing antipsychotics of patients with chronic schizophrenia involves several risks. Switching to aripiprazole is especially difficult. We investigated switching methods and related factors for successful switching patients with chronic schizophrenia to aripiprazole. OBJECTIVES: This study was a multi-center historical cohort study and approved by the research ethics committee of Okayama University Hospital and Okayama Psychiatric Medical Center. We compared survival proportions of 178 chronic schizophrenia patients who continued aripiprazole monotherapy for 6 months after non-direct switching (add-on switching (n = 45), cross switching (n = 62)) or direct switching (n = 71). We adjusted possible confounders using a Cox proportional hazards model. RESULTS: Of patients with chronic schizophrenia, 56.7% (101/178) were switched to aripiprazole monotherapy, and 55.0% (98/178) showed improvement in symptoms as demonstrated by the Clinical Global Impression Severity score. Kaplan-Meier survival curves showed that non-direct switching had a higher survival proportion than direct switching (log-rank test, p = 0.012). Even after adjusting for several variables using a Cox proportional hazards model, add-on switching had a significantly lower hazard at 6 months than direct switching (hazard ratio 0.42, 95% confidence interval 0.21-0.82, P = 0.01). In cases of switching to aripiprazole for psychiatric symptoms, non-direct switching had a lower hazard than direct switching (hazard ratio 0.41, 95% confidence interval 0.21-0.81, P = 0.01) but was not significant for adverse reaction. When aripiprazole was switched from olanzapine, add-on switch showed the lowest hazard ratio for continuation (hazard ratio 0.29, 95% confidence interval 0.07-1.11, P = 0.07). CONCLUSIONS: Flexibility in strategies when switching to aripiprazole may induce a better outcome for patients with chronic schizophrenia.

Identification and quantification of oxygen species adsorbed on Pt(111) single-crystal and polycrystalline Pt electrodes by photoelectron spectroscopy.

We have positively identified oxygen species on Pt(111) single-crystal and polycrystalline Pt electrodes in N2-purged 0.1 M HF solution by X-ray photoelectron spectroscopy combined with an electrochemical cell. Four oxygen species (Oad, OHad, and two types of water molecules) were distinguished. The binding energies of each species were nearly constant over the whole potential region and independent of the single- or polycrystalline electrodes. The coverages, however, varied considerably and were dependent on the electrode potential. We have for the first time demonstrated clear differences in the surface oxidation processes for Pt(111) and polycrystalline Pt electrodes.

Electronic structures of Pt-Co and Pt-Ru alloys for CO-tolerant anode catalysts in polymer electrolyte fuel cells studied by EC-XPS.

CO tolerance at pure Pt, Pt-Co, and Pt-Ru alloys was investigated by X-ray photoelectron spectroscopy combined with an electrochemical cell (EC-XPS) in order to discover a hint for designing higher performance anode catalysts. After the electrochemical stabilization and/or CO adsorption, these electrodes were immediately transferred to the XPS chamber without exposure to air to avoid contamination of the surfaces. It was revealed that alloying with Co or Ru modified the electronic structures of Pt atoms, resulting in a positive core level (CL) shift of Pt 4f(7/2) which could weaken the Pt-CO interaction. For the Pt-Co alloy electrode, the Pt 4f(7/2) CL shift remained after the electrochemical stabilization despite Co dissolution and formation of a Pt skin layer. Changes in surface core level shifts (DeltaSCLSs) induced by CO adsorption were evaluated and related to the CO adsorption energy. The values of DeltaSCLS at these alloys were smaller than that of pure Pt, indicating that Ru and Co are effective elements to weaken the bond strength of Pt-CO.