Kreishohlprofil-X-Knoten aus nichtrostenden Stählen unter Axialbeanspruchung

Die Bemessung geschweißter, unversteifter Knoten aus Kreishohlprofilen (KHP) aus nichtrostenden Stählen ist derzeit ungenügend geregelt, da alle verfügbaren Bemessungsregeln auf Ergebnissen von Untersuchungen an KHP-Knoten aus un‐ und niedriglegierten Baustählen basieren. Die vorliegende Arbeit befasst sich mit dem Tragverhalten ebener KHP-X-Knoten aus nichtrostenden Stählen unter vorwiegend ruhender Axialbeanspruchung. Ein Bemessungskonzept wurde entwickelt

Kreishohlprofil-X-Knoten aus nichtrostenden Stählen unter Axialbeanspruchung

Die vorliegende Arbeit befasst sich mit dem Tragverhalten ebener KHP-X-Knoten aus nichtrostenden Stählen unter vorwiegend ruhender Axialbeanspruchung. Experimentelle und numerische Untersuchungen wurden hierzu an der Versuchsanstalt für Stahl, Holz und Steine des Karlsruher Instituts für Technologie (KIT) durchgeführt. Ein Bemessungskonzept für axial beanspruchte KHP-X-Knoten aus nichtrostenden Stählen wurde entwickelt

Involvement of A1 adenosine receptors in osmotic volume regulation of retinal glial cells in mice

PURPOSE: Osmotic swelling of Müller glial cells has been suggested to contribute to retinal edema. We determined the role of adenosine signaling in the inhibition of Müller cell swelling in the murine retina. METHODS: The size of Müller cell somata was recorded before and during perfusion of retinal sections and isolated Müller cells with a hypoosmolar solution. Retinal tissues were freshly isolated from wild-type mice and mice deficient in A(1) adenosine receptors (A(1)AR(-/-)), or cultured as whole-mounts for three days. The potassium conductance of Müller cells was recorded in isolated cells, and retinal slices were immunostained against Kir4.1. RESULTS: Hypotonic exposure for 4 min induced a swelling of Müller cell bodies in retinal slices from A(1)AR(-/-) mice but not wild-type mice. Pharmacological inhibition of A(1) receptors or of the ecto-5'-nucleotidase induced hypoosmotic swelling of Müller cells from wild-type mice. Exogenous adenosine prevented the swelling of Müller cells from wild-type but not A(1)AR(-/-) mice. The antiinflammatory corticosteroid, triamcinolone acetonide, inhibited the swelling of Müller cells from wild-type mice; this effect was blocked by an antagonist of A(1) receptors. The potassium conductance of Müller cells and the Kir4.1 immunolabeling of retinal slices were not different between A(1)AR(-/-) and wild-type mice, both in freshly isolated tissues and retinal organ cultures. CONCLUSIONS: The data suggest that autocrine activation of A(1) receptors by extracellularly generated adenosine mediates the volume homeostasis of Müller cells in the murine retina. The swelling-inhibitory effect of triamcinolone is mediated by enhancement of endogenous adenosine signaling

A critique of robotics in health care

When the social relevance of robotic applications is addressed today, the use of assistive technology in care settings is almost always the first example. So-called care robots are presented as a solution to the nursing crisis, despite doubts about their technological readiness and the lack of concrete usage scenarios in everyday nursing practice. We inquire into this interconnection of social robotics and care. We show how both are made available for each other in three arenas: innovation policy, care organization, and robotic engineering. First, we analyze the discursive “logics” of care robotics within European innovation policy, second, we disclose how care robotics is encountering a historically grown conflict within health care organization, and third we show how care scenarios are being used in robotic engineering. From this diagnosis, we derive a threefold critique of robotics in healthcare, which calls attention to the politics, historicity, and social situatedness of care robotics in elderly care.TU Berlin, Open-Access-Mittel – 202

Concept for a Dual Frequency Dual Constellation GBAS

This paper proposes one possible concept for a dual frequency dual constellation GBAS architecture. It is based on a single frequency L5/E5a mode as primary processing scheme for best standard performance, a switch to an ionosphere free combination in case of ionospheric disturbances and supporting also classical GBAS approach service types (GAST) C and D for single frequency GPS-based CAT I and CAT II/III modes. The concept is supported by a proposal of how to transmit the required corrections in the existing capacity limited VDB broadcast and is backwards compatible to legacy GBAS. A discussion about the benefits and remaining issues of the proposed architecture concludes the paper

Reinforcement magnitudes modulate subthalamic beta band activity in patients with Parkinson's disease

We set out to investigate whether beta oscillations in the human basal ganglia are modulated during reinforcement learning. Based on previous research, we assumed that beta activity might either reflect the magnitudes of individuals' received reinforcements (reinforcement hypothesis), their reinforcement prediction errors (dopamine hypothesis) or their tendencies to repeat versus adapt responses based upon reinforcements (status-quo hypothesis). We tested these hypotheses by recording local field potentials (LFPs) from the subthalamic nuclei of 19 Parkinson's disease patients engaged in a reinforcement-learning paradigm. We then correlated patients' reinforcement magnitudes, reinforcement prediction errors and response repetition tendencies with task-related power changes in their LFP oscillations. During feedback presentation, activity in the frequency range of 14 to 27 Hz (beta spectrum) correlated positively with reinforcement magnitudes. During responding, alpha and low beta activity (6 to 18 Hz) was negatively correlated with previous reinforcement magnitudes. Reinforcement prediction errors and response repetition tendencies did not correlate significantly with LFP oscillations. These results suggest that alpha and beta oscillations during reinforcement learning reflect patients' observed reinforcement magnitudes, rather than their reinforcement prediction errors or their tendencies to repeat versus adapt their responses, arguing both against an involvement of phasic dopamine and against applicability of the status-quo theory

Genetically Encoded Voltage Indicators in Circulation Research

Membrane potentials display the cellular status of non-excitable cells and mediate communication between excitable cells via action potentials. The use of genetically encoded biosensors employing fluorescent proteins allows a non-invasive biocompatible way to read out the membrane potential in cardiac myocytes and other cells of the circulation system. Although the approaches to design such biosensors date back to the time when the first fluorescent-protein based Förster Resonance Energy Transfer (FRET) sensors were constructed, it took 15 years before reliable sensors became readily available. Here, we review different developments of genetically encoded membrane potential sensors. Furthermore, it is shown how such sensors can be used in pharmacological screening applications as well as in circulation related basic biomedical research. Potentials and limitations will be discussed and perspectives of possible future developments will be provided