Cathodoluminescence characterization of Ge-doped CdTe crystals

Cathodoluminescence (CL) microscopic techniques have been used to study the spatial distribution of structural defects and the deep levels in CdTe:Ge bulk crystals. The effect of Ge doping with concentrations of 10(17) and 10(19) cm(-3) on the compensation of V-Cd in CdTe has been investigated. Dependence of the intensity distribution of CL emission bands on the dopant concentration has been studied. Ge doping causes a substantial reduction of the generally referred to 1.40 eV luminescence, which is often present in undoped CdTe crystals, and enhances the 0.91 and 0.81 eV emissions

Crystal structures of self-assembled nanotubes from flexible macrocycles by weak interactions

8 páginas, 7 figuras, 2 tablas, 2 esquemas.Herein we report the crystal structures of tubular self-assemblies of flexible macrooligolides. The assembly is driven by the propensity of the macrocycles to create nearly flat structures displaying a void space within them and the cooperativity of weak directional interactions such as dipole–dipole interactions and CH***Ohydrogen bonds and non-directional interactions such as van der Waals contacts. The significance of the stereochemistry and the size of the cavity in the formation of the nanotubes are also studied.This research was supported by the Spanish MICINN-FEDER (CTQ2008-03334/BQU, CTQ2008-06806-C02-01/BQU and CTQ2008-06754-C04-01/PPQ), the MSC (RTICC RD06/0020/ 1046) and the Canary Islands FUNCIS (PI 01/06).Peer reviewe

The Combined Dexamethasone/CRH Test (DEX/CRH Test) and Prediction of Acute Treatment Response in Major Depression

In this study the predictive value of the combined dexamethasone/CRH test (DEX/CRH test) for acute antidepressant response was investigated. In 114 depressed inpatients suffering from unipolar or bipolar depression (sample 1) the DEX/CRH test was performed at admission and shortly before discharge. During their stay in the hospital patients received different antidepressant treatment regimens. At admission, the rate of nonsuppression (basal cortisol levels >75.3 nmol/l) was 24.6% and was not related to the later therapeutic response. Moreover, 45 out of 114 (39.5%) patients showed an enhancement of HPA axis function at discharge in spite of clinical improvement. In a second sample, 40 depressed patients were treated either with reboxetine or mirtazapine for 5 weeks. The DEX/CRH test was performed before, after 1 week, and after 5 weeks of pharmacotherapy. Attenuation of HPA axis activity after 1 week was associated with a more pronounced alleviation of depressive symptoms after 5-week mirtazapine treatment, whereas downregulation of HPA system activity after 5 weeks was related to clinical response to reboxetine. However, early improvement of HPA axis dysregulation was not necessarily followed by a beneficial treatment outcome. Taken together, performance of a single DEX/CRH test does not predict the therapeutic response. The best predictor for response seems to be an early attenuation of HPA axis activity within 1 or 2 weeks. However, early improvement of HPA system dysfunction is not a sufficient condition for a favourable response. Since a substantial part of depressive patients display a persistence of HPA axis hyperactivity at discharge, downregulation of HPA system function is not a necessary condition for acute clinical improvement either. Our data underline the importance of HPA axis dysregulation for treatment outcome in major depression, although restoration of HPA system dysfunction seems to be neither a necessary nor a sufficient determinant for acute treatment response