171,651 research outputs found
Highly conductive ion tracks in tetrahedral amorphous carbon by irradiation with 30 MeV C-60 projectiles
No full textElectrically conducting ion tracks are produced when high-energy heavy ions pass through a layer of tetrahedral amorphous carbon (ta-C). The tracks are embedded in the insulating ta-C matrix and have a diameter of about 8 nm. Earlier studies showed that the electrical currents through individual tracks produced with Au and U projectiles exhibit rather large track-to-track fluctuations. In striking contrast, 30 MeV C-60 cluster ions are shown to generate conducting tracks of very narrow conductivity distributions. Their current-versus-voltage curves are linear at room temperature. We also investigated ta-C films doped with B, N, Cu and Fe at a concentration of 1 or 2 at.%. In particular, Cu-and Fe-doped samples show increased ion track conductivity.DFG [Ho1125/17-1]; BMBF [05KK4MGA/9]Open-Access-Publikationsfonds 201
Systematisierung von in Deutschland angebotenen und durchgeführten (Präventions-)Programmen gegen islamistisch motivierte Radikalisierung außerhalb des Justizvollzuges (Kurzfassung)
No full textTrautmann C, Zick A. Systematisierung von in Deutschland angebotenen und durchgeführten (Präventions-)Programmen gegen islamistisch motivierte Radikalisierung außerhalb des Justizvollzuges (Kurzfassung).; 2016
Systematic Classification of in Germany Offered and Implemented (Prevention) Programmes Against Islamist Motivated Radicalisation Outside the Justice System
No full textTrautmann C, Zick A. Systematic Classification of in Germany Offered and Implemented (Prevention) Programmes Against Islamist Motivated Radicalisation Outside the Justice System.; 2016
Diagnostic testing in suspected fluoroquinolone hypersensitivity
No full textP>Background Because of their broad antibacterial activity in the gram-negative and gram-positive spectrum, high oral bioavailability, and good tissue penetration, fluoroquinolone antibiotics are widely used. Besides direct drug-related side-effects, fluoroquinolones may cause hypersensitivity reactions. Objective The aim of this retrospective analysis was to present the results of diagnostic testing in cases of clinically suspected fluoroquinolone-induced immediate or delayed hypersensitivity. Methods We studied 101 patients with a history of immediate or delayed hypersensitivity symptoms in temporal relation to treatment with a fluoroquinolone antibiotic using standardized skin testing, followed by oral challenges. Patients with anaphylaxis symptoms were further evaluated with in vitro tests. Results Fluoroquinolone hypersensitivity was excluded in 71 patients by tolerated oral challenge tests. During positive challenge tests, six patients (three out of these had positive and three had negative skin prick tests) developed anaphylaxis symptoms but the presumed IgE-mediated mechanism could not be confirmed by in vitro tests. Patch testing was constantly negative; however, in two patients a rash was induced by the challenge tests. Conclusion History alone leads clearly to a considerable over-estimation of fluoroquinolone hypersensitivity. Moreover, skin or in vitro tests do not seem to be very useful in identifying hypersensitive patients. Challenge tests appear to be necessary for definitely confirming or ruling out fluoroquinolone hypersensitivity. Cite this as: C. S. Seitz, E. B. Brocker and A. Trautmann, Clinical & Experimental Allergy, 2009 (39) 1738-1745
Systematisierung von in Deutschland angebotenen und durchgeführten (Präventions-)Programmen gegen islamistisch motivierte Radikalisierung außerhalb des Justizvollzuges (Langfassung)
No full textTrautmann C, Zick A. Systematisierung von in Deutschland angebotenen und durchgeführten (Präventions-)Programmen gegen islamistisch motivierte Radikalisierung außerhalb des Justizvollzuges (Langfassung).; 2016
Nano-hillock formation in diamond-like carbon induced by swift heavy projectiles in the electronic stopping regime: Experiments and atomistic simulations
Full text linkThe formation of surface hillocks in diamond-like carbon is studied experimentally and by means of large-scale molecular dynamics simulations with 5 × 106 atoms combined with a thermal spike model. The irradiation experiments with swift heavy ions cover a large electronic stopping range between ∼12 and 72 keV/nm. Both experiments and simulations show that beyond a stopping power threshold, the hillock height increases linearly with the electronic stopping, and agree extremely well assuming an efficiency of approximately 20% in the transfer of electronic energy to the lattice. The simulations also show a transition of sp3 to sp2bonding along the tracks with the hillocks containing almost no sp3 contribution.Fil: Schwen, D.. University of Illinois at Urbana-Champaign. Department of Materials Science and Engineering; Estados UnidosFil: Bringa, Eduardo Marcial. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Krauser, J.. Hochschule Harz; AlemaniaFil: Weidinger, A.. Helmholtz-Zentrum Berlin fur Materialien und Energie; AlemaniaFil: Trautmann, C.. GSI Helmholtzzentrum; AlemaniaFil: Hofsass, H.. Universitat Gottingen. Physikalisches Institut; Alemani
Parrondo's Paradox for Discrete-Time Quantum Walks in Momentum Space
Full text linkWe investigate the possibility of implementing a sequence of quantum walks whose probability distributions give an overall positive winning probability, while it is negative for the single walks (Parrondo's paradox). In particular, we have in mind an experimental realization with a Bose-Einstein condensate in which the walker's space is momentum space. Experimental problems in the precise implementation of the coin operations for our discrete-time quantum walks are analyzed in detail. We study time-dependent phase fluctuations of the coins as well as perturbations arising from the finite momentum width of the condensate. We confirm the visibility of Parrondo's paradox for experimentally available time scales of up to a few hundred steps of the walk
Präventionsprogramme gegen islamistisch motivierte Radikalisierung: Klassifizierung der Ansätze und ihrer Begründetheit
No full textKahl W, Trautmann C, Zick A. Präventionsprogramme gegen islamistisch motivierte Radikalisierung: Klassifizierung der Ansätze und ihrer Begründetheit. Forum Kriminalprävention. 2015;(3):3-5
Prävention von islamistischer Radikalisierung und Gewalt - Eine Systematisierung von Präventionsansätzen in Deutschland
No full textTrautmann C, Kahl W, Zick A. Prävention von islamistischer Radikalisierung und Gewalt - Eine Systematisierung von Präventionsansätzen in Deutschland. Forum Kriminalprävention. 2017;(1):3-9
Field emission enhancement by graphitic nano scale channels through ta C layers
No full textA key issue in field emission FE from CVD diamond and other carbon films is to understand the role that non diamond inclusions and conduction pathways in the material have on the FE process. FE is significantly enhanced, apart from geometric enhancements due to rough surface morphologies, by the presence of non diamond phases embedded in the diamond matrix. These phases appear in the form of grain boundaries, graphitic inclusions, graphite nano particles and others. It is, however, not clear in most reports, what the relative contribution of surface morphology and the presence of conductive channels to improved emission is. To investigate the possibility of FE originating from graphitic regions in a perfectly smooth material, we performed ion irradiation to selectively transform diamond like carbon sp3 bonding into graphite like sp2 bonding material. Single ion tracks were formed by implanting high energy single ions at extremely low doses through a thin smooth amorphous tetrahedral amorphous carbon ta C layer. The layers were thin enough for the ions to penetrate through them and stop in the substrate. N doped conductive and un doped ta C films were used and the FE results were compared. Four ion implantation schemes were used a 1 GeV U ions at a low dose; b sub MeV Xe ions at a low dose; both were meant to form well separated single ion tracks through the material; c sub MeV C ions at a high dose, for complete material transformation; and d un implanted sample as a control. Field emission turn on conditions were carefully studied for these, employing a very slow voltage ramp up, to avoid undesired vacuum electric discharges, known to result in a conditioning affect on FE. Field emission seems to initiate at the lowest applied field for samples that include nano scale graphitized channels threading all the way through the layer, as realized by single ion implantations. A 40 reduction in the field required for emission onset is found for all samples with single ion tracks compared to the un implanted sample. However, the sample implanted for full coverage transformation shows no emission up to at least 100 V amp; 956;m. The observed improvement in FE is shown to be consistent with field enhancement calculations due to conductive pathways in the materia
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