Electromechanical losses in carbon- and oxygen-containing bulk AlN single crystals

Bulk single-crystalline aluminum nitride (AlN) is potentially a key component for low-loss high-temperature piezoelectric devices. However, the incorporation of electrically active impurities and defects during growth of AlN may adversely affect the performance of piezoelectric resonators especially at high temperatures. The electrical conductivity and electromechanical losses in bulk AlN single crystals are analyzed in the temperature range of 300–1200 K with respect to various contents of growth-related impurities in them. For AlN with [O]/[C] ≤ 1, an increase of electrical conductivity due to thermal activation of charge carriers in the temperature range of 850–1200 K has been observed and was determined to be a major contribution to electromechanical losses Q−1 rising up to maximum values of about 10−3 at 1200 K. As the oxygen content in AlN increased, the magnitude and the activation energy of high-temperature electrical conductivity increased. In oxygen-dominated AlN, two major thermally activated contributions to electromechanical losses were observed, namely, the anelastic relaxations of point defects at temperatures of 400–800 K and electrical conductivity at T > 800 K

Re-evaluation of phytohormone-independent division of tobacco protoplast-derived cells

We have used a [3H] thymidine incorporation assay and microscopic observation in order to reassess recently published data dealing with the response of tobacco protoplasts to phytohormones, lipochitooligosaccharides and peptides (Harling et al., 1997; Hayashi et al., 1992; Miklashevichs et al., 1996; Miklashevichs et al., 1997; Rohrig et al., 1995; Rohrig et al., 1996; van de Sande et al., 1996; Walden et al., 1994). These proliferation assays reveal that, in contrast to published data, isolated cells of the investigated mutant plant lines axi159 (Hayashi et al., 1992; Walden et al., 1994), axi4/1 (Harling et al., 1997) and cyil (Miklashevichs et al., 1997), which were generated by activation T-DNA tagging, were unable to grow in the absence of auxin or cytokinin. Furthermore, lipochitooligosaccharides which play a key role in the induction of nodules on roots of legumes were unable to promote auxin- or cytokinin-independent cell division in tobacco protoplasts as claimed by Rohrig et al. (1995, 1996). The finding of van de Sande et al. (1996) that ENOD40 confers tolerance of high auxin concentration to wild-type tobacco protoplasts was also reinvestigated. The results of our investigations show that we were unable to reproduce the proliferation data presented in this study, which were obtained by counting tobacco protoplast-derived cells undergoing division. In total, none of the published data on phytohormone-independent division of tobacco cells could be reproduced.Peer reviewe

Neuropeptide S receptor gene - converging evidence for a role in panic disorder

Animal studies have suggested neuropeptide S (NPS) and its receptor (NPSR) to be involved in the pathogenesis of anxiety-related behavior. In this study, a multilevel approach was applied to further elucidate the role of NPS in the etiology of human anxiety. The functional NPSR A/T (Asn¹⁰⁷Ile) variant (rs324981) was investigated for association with (1) panic disorder with and without agoraphobia in two large, independent case-control studies, (2) dimensional anxiety traits, (3) autonomic arousal level during a behavioral avoidance test and (4) brain activation correlates of anxiety-related emotional processing in panic disorder. The more active NPSR rs324981 T allele was found to be associated with panic disorder in the female subgroup of patients in both samples as well as in a meta-analytic approach. The T risk allele was further related to elevated anxiety sensitivity, increased heart rate and higher symptom reports during a behavioral avoidance test as well as decreased activity in the dorsolateral prefrontal, lateral orbitofrontal and anterior cingulate cortex during processing of fearful faces in patients with panic disorder. The present results provide converging evidence for a female-dominant role of NPSR gene variation in panic disorder potentially through heightened autonomic arousal and distorted processing of anxiety-relevant emotional stimuli

Gender Differences in Associations of Glutamate Decarboxylase 1 Gene (GAD1) Variants with Panic Disorder

Background: Panic disorder is common (5% prevalence) and females are twice as likely to be affected as males. The heritable component of panic disorder is estimated at 48%. Glutamic acid dehydrogenase GAD1, the key enzyme for the synthesis of the inhibitory and anxiolytic neurotransmitter GABA, is supposed to influence various mental disorders, including mood and anxiety disorders. In a recent association study in depression, which is highly comorbid with panic disorder, GAD1 risk allele associations were restricted to females. Methodology/Principal Findings: Nineteen single nucleotide polymorphisms (SNPs) tagging the common variation in GAD1 were genotyped in two independent gender and age matched case-control samples (discovery sample n = 478; replication sample n = 584). Thirteen SNPs passed quality control and were examined for gender-specific enrichment of risk alleles associated with panic disorder by using logistic regression including a genotype×gender interaction term. The latter was found to be nominally significant for four SNPs (rs1978340, rs3762555, rs3749034, rs2241165) in the discovery sample; of note, the respective minor/risk alleles were associated with panic disorder only in females. These findings were not confirmed in the replication sample; however, the genotype×gender interaction of rs3749034 remained significant in the combined sample. Furthermore, this polymorphism showed a nominally significant association with the Agoraphobic Cognitions Questionnaire sum score. Conclusions/Significance: The present study represents the first systematic evaluation of gender-specific enrichment of risk alleles of the common SNP variation in the panic disorder candidate gene GAD1. Our tentative results provide a possible explanation for the higher susceptibility of females to panic disorder

Oxygen partial pressure control for microgravity experiments

A system consisting of a high-temperature yttrium-stabilized zirconia (YSZ) based oxygen ion pump and potentiometric sensor enables precise measurement and control of oxygen partial pressure, pO2, at elevated temperatures within 0.2 to 10^-20 bar. <the principle of operation as well as the influence of temperature and gas buffers like H2/H2O on the pO2 is discussed. The ion pump is controlled by a microcontroller system and adjusts the oxygen partial pressure with an uncertainty of Delta-log(pO2)<0.02 and response times between 5 and 90s over the entire pO2 range. The oxygen ion pump is tested in combination with the electromagnetic levitation. Here, the surface tension of molten Ni at 1720 °C as a function of oxygen partial pressure is determined. A good agreement of this measurement with calculated value confirms the applicability of the system for high-temperature measurement and control of pO2. The developed hardware is suitable for the electromagnetic levitation facility onboard the international space station (ISS)

Berufliche Rollen heutiger Ergotherapeut:innen

Referat im Symposium "Paradigmenwechsel in der Ergotherapie – Ergotherapie in der Psychiatrie heute"Das berufliche Rollenmodell „Canadian Medical Education Directives for Specialists“ (CanMEDS) (Tannenbaum et al., 2009), das auf Grundlagen wissenschaftlicher Arbeiten entwickelt wurde, bietet eine solide Grundlage, die beruflichen Rollen und dazugehörigen Kompetenzen eines Gesundheitsfachberufes abzubilden. In der Schweiz bspw. wurden anhand dieses Profils 2009 gesamtschweizerisch einheitliche Abschlusskompetenzen für die Ergotherapie durch die ausbildungsanbietenden Fachhochschulen beschrieben. Der deutsche Berufsverband für Ergotherapie (DVE) publizierte 2019 das ebenfalls daraus abgeleitete „Kompetenzprofil Ergotherapie“. In diesem Vortrag wird das CanMEDS kurz vorgestellt sowie sein Einsatz in anderen Ländern zur Beschreibung ergotherapeutischer Rollen und Kompetenzen. Für die Ergotherapeut:in im psychatrischen Kontext wird aufgezeigt, welche Rollen sie im heutigen modernen Paradigma wie einnimmt