Quantum transport through STM-lifted single PTCDA molecules

Using a scanning tunneling microscope we have measured the quantum conductance through a PTCDA molecule for different configurations of the tip-molecule-surface junction. A peculiar conductance resonance arises at the Fermi level for certain tip to surface distances. We have relaxed the molecular junction coordinates and calculated transport by means of the Landauer/Keldysh approach. The zero bias transmission calculated for fixed tip positions in lateral dimensions but different tip substrate distances show a clear shift and sharpening of the molecular chemisorption level on increasing the STM-surface distance, in agreement with experiment.Comment: accepted for publication in Applied Physics

Messung von Venendruckwerten im Rahmen der EURO-MIR-Mission Schlussbericht

In cooperation with the Institute of Physiologie of the Free University Berlin a versatile portable device for measurement, storage as well as replay of analog signals was developed under special respect of the measurement of the central venous blood pressure of astronauts under zero-g. The components of this device are an analog input, a micro processor for control and digital storage, a LCD-display serving for the graphical representation of the measured data as well as for user support and an absolute pressure measurement unit. In the case of blood pressure measurement periodic signals of about 1 Hz have to be recorded at a band width of about 1 KHz. For data storage a solid state disk of 40 MByte capacity, a rotating storage of 1 GByte or an external storage can be used. For further data evaluation digital as well as analog outputs are provided. The device is designed in 5 V-technology concerning physiological use and minimized with respect to dimension, mass and power consumption concerning the use in space. In addition the pressure transducers already used on D1-mission have been recalibrated for this actual purpose and adapted in respect to their electrical as well as electronical interfaces. (orig.)SIGLEAvailable from TIB Hannover: F97B530+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany); Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA) GmbH, Bonn (Germany)DEGerman

Messung von Gewebeschichtdicken und -verformbarkeit auf der Raumstation 'MIR' Schlussbericht

A system for the measurement of the skin thickness along the human's body axis as well as the compliance under microgravity conditions was developed. The measuring principle is based on an ultrasonic detection of the distance between skin and bone surface, combined with a pressure measurement. The system consists in a central electronic unit for control, data storage and data evaluation and a set of three sensor units for leg, head and compliance. During the compliance measurement the skin becomes pressurized with positive and negative differential pressure head. The resulting change of skin thickness is a measure for elasticity as well as compressibility of the skin. The system was used successfully by german, french and russian astronauts on several MIR-Missions and D2-Mission. (orig.)SIGLEAvailable from TIB Hannover: F95B326+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Gesundheit und Gesundheitsversorgung von trans Personen während der COVID‑19-Pandemie : eine Online-Querschnittstudie in deutschsprachigen Ländern

Background and objective Since spring of 2020, the COVID-19 pandemic has disrupted our day-to-day lives and led to negative consequences in various areas of life, including mental and physical wellbeing. In this article, we take a closer look at the situation of trans people, who - due to experiences with discrimination and marginalization as well as their specific health-related interests - could be characterized by a particular vulnerability. Methods Using an online cross-sectional survey, which we designed collaboratively with experts from the trans community, we investigated the mental and physical health of trans people from German-speaking countries and their access to trans-related healthcare during the COVID-19 pandemic in the period from 1 May 2020 to 31 January 2021. Results Since the beginning of the COVID-19 pandemic, trans people have experienced barriers in access to gender-affirming treatments, mental health services, and COVID-19-related medical care. At the same time, trans people reported being affected by chronic diseases disproportionately more often than the general population, including those leading to a higher risk for poorer outcomes of a COVID-19 infection. Moreover, the participants reported being exposed to many risk factors associated with higher mental distress (e.g., having a chronic illness, belonging to a minority based on a non-heterosexual orientation, or having a low income). Discussion The results of this survey indicate that prior vulnerabilities with regards to health problems and the restricted access to an informed and qualified transgender healthcare were exacerbated by the COVID-19 pandemic

Entwicklung von Verfahren und Werkzeugsystemen zur Hydroumformung hoeherfester Stahlbleche

Available from TIB Hannover: RR 7808(274) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEStifterverband fuer die Deutsche Wissenschaft e.V., Essen (Germany). Stiftung StahlanwendungsforschungDEGerman

Cross section and neutron angular distribution measurements of neutron scattering on natural iron

New measurements of the neutron scattering double differential cross section of iron were carried out at the neutron time-of-flight facilities GELINA and nELBE. A neutron spectrometer consisting of an array of up to 32 liquid organic scintillators was employed, which was designed to measure the scattering differential cross section at eight scattering angles and to simultaneously determine the integral cross section via numerical quadrature. The separation of elastic from inelastic scattering was achieved by analysing the time-of flight dependent light-output distributions to determine the scattered neutron energy. The method was validated by studying elastic scattering on carbon and it was proved to work well for the determination of the elastic cross section. Here, the possibility to extend it to inelastic scattering was investigated too. For these experiments a sample of natural iron was used and the results cover the incident neutron energy range from 2 to 6 MeV. Both the differential and the integral elastic cross sections were produced for natFe, while for inelastic scattering, partial angular distributions for scattering from the first excited level of 56Fe could be determined.JRC.G.2-Standards for Nuclear Safety, Security and Safeguard