Residual strain in free-standing CdTe nanowires overgrown with HgTe

We investigate the crystal properties of CdTe nanowires overgrown with HgTe. Scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM) confirm, that the growth results in a high ensemble uniformity and that the individual heterostructures are single-crystalline, respectively. We use high-resolution X-ray diffraction (HRXRD) to investigate strain, caused by the small lattice mismatch between the two materials. We find that both CdTe and HgTe show changes in lattice constant compared to the respective bulk lattice constants. The measurements reveal a complex strain pattern with signatures of both uniaxial and shear strains present in the overgrown nanowires

Fine structure of "zero-mode" Landau levels in HgTe/HgCdTe quantum wells

HgTe/HgCdTe quantum wells with the inverted band structure have been probed using far infrared magneto-spectroscopy. Realistic calculations of Landau level diagrams have been performed to identify the observed transitions. Investigations have been greatly focused on the magnetic field dependence of the peculiar pair of "zero-mode" Landau levels which characteristically split from the upper conduction and bottom valence bands, and merge under the applied magnetic field. The observed avoided crossing of these levels is tentatively attributed to the bulk inversion asymmetry of zinc blend compounds.Comment: 5 pages, 4 figure

Macrophage-derived Lipocalin-2 contributes to ischemic resistance mechanisms by protecting from renal injury

Renal ischemia-reperfusion injury triggers an inflammatory response associated to infiltrating macrophages which determines the further outcome of disease. Brown Norway rats are known to show endogenous resistance to ischemia-induced renal damage. By contrast, Sprague Dawley rats exhibit a higher susceptibility to ischemic injury. In order to ascertain cytoprotective mechanisms, we focused on the implication of lipocalin-2 protein in main resistance mechanisms in renal ischemia/reperfusion injury by using adoptive macrophage administration, genetically modified ex vivo either to overexpress or to knockdown lipocalin-2. In vitro experiments with bone marrow-derived macrophages both from Brown Norway rats and from Sprague Dawley rats under hypoxic conditions showed endogenous differences regarding cytokine and lipocalin-2 expression profile in the two strains. Most interestingly, we observed that macrophages of the resistant strain express significantly more lipocalin-2. In vivo studies showed that tubular epithelial cell apoptosis and renal injury significantly increased and reparative markers decreased in Brown Norway rats after injection of lipocalin-2-knockdown macrophages, while the administration of lipocalin-2-overexpressing cells significantly decreased Sprague Dawley susceptibility. These data point to a crucial role of macrophage-derived lipocalin-2 in endogenous cytoprotective mechanisms. We conclude that expression of lipocalin-2 in tissue-infiltrating macrophages is pivotal for kidney-intrinsic cytoprotective pathways during ischemia reperfusion injury.The authors would like to thank M Ángeles Muñoz for her excellent technical support. This work was supported by grants from FIS PI12/00720 from Instituto de Salud Carlos III cofunded by FEDER funds/European Regional Development Fund (ERDF)-a way to buid Europe- and SENEFRO (awarded to AS) and SAF 2012-39947-02 (awarded to GH). MJ was supported by a grant from Fritz Thyssen Stiftung (Az.10.12.2.156) and a grant from University of Frankfurt (Focus Line B) and AS is supported by Miguel Servet II contracting system (CPII 14/00026).Peer Reviewe

Dirac-screening stabilized surface-state transport in a topological insulator

We report magnetotransport studies on a gated strained HgTe device. This material is a threedimensional topological insulator and exclusively shows surface state transport. Remarkably, the Landau level dispersion and the accuracy of the Hall quantization remain unchanged over a wide density range ($3 \times 10^{11} cm^{-2} < n < 1 \times 10^{12} cm^{-2}$). This implies that even at large carrier densities the transport is surface state dominated, where bulk transport would have been expected to coexist already. Moreover, the density dependence of the Dirac-type quantum Hall effect allows to identify the contributions from the individual surfaces. A $k \cdot p$ model can describe the experiments, but only when assuming a steep band bending across the regions where the topological surface states are contained. This steep potential originates from the specific screening properties of Dirac systems and causes the gate voltage to influence the position of the Dirac points rather than that of the Fermi level.Comment: 12 pages 4 figure

Nonverbal behavior during standardized interviews in patients with schizophrenia spectrum disorders

Several studies have consistently shown that patients with schizophrenia or schizophrenia spectrum disorders (SSD) can be distinguished from normal controls on the basis of their nonverbal behavior during standardized interviews, with considerable interactions between negative symptoms and poor facial expressivity. However, most studies have examined unmedicated patients, and gender of both interviewer and interviewee has not been taken into account. In this study we assessed the nonverbal behavior of male and female patients with SSD who were receiving second-generation antipsychotic medication (SGA) using the Ethological Coding System for Interviews (Troisi, 1998). In addition, we used a novel 5-factor model of the Positive and Negative Symptom Scale (PANSS, van der Gaag et al., 2006) to correlate nonverbal behavior with standard psychopathology ratings. Our findings strongly resembled results of previous studies into nonverbal behavior of patients with SSD, despite differences in cultural backgrounds and gender of the interviewer. Negative symptoms were inversely correlated with several of the nonverbal behavioral dimensions. Medication dose did not correlate with any one of the behavioral or psychopathological measures. Patients with SSD make less use of their nonverbal behavioral repertoire compared with controls, independent of antipsychotic treatment. Culture-specific nonverbal expressivity seems to play an additional (minor) role in distinguishing patients from healthy controls