520 research outputs found

    Retrospektive Bestimmung der elektromagnetischen Exposition durch analoge Rundfunksender im Rahmen von KiSS

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    Im Rahmen einer epidemiologischen Fall-Kontroll-Studie zur Untersuchung eines möglichen Zusammenhangs zwischen der Häufigkeit kindlicher Leukämien und elektromagnetischer Strahlung (,,KiSS" – <b>Ki</b>ndliche Leukämien und Expositionen in der Umgebung von hochfrequenten <b>S</b>ende<b>s</b>tationen) soll die Exposition durch leistungsstarke analoge Rundfunksender retrospektiv (Zeitraum 1982–2003) quantifiziert werden. Die zu betrachtenden Sendernetze für AM-Hörfunk, FM-Hörfunk und analoges Fernsehen unterscheiden sich nicht nur hinsichtlich der Modulationsart und der von den Einzelsendern abgestrahlten Leistung, sondern auch in der Netzkonfiguration und den je nach Wellenbereich verschiedenen Strahlungseigenschaften der Sendeantennen. Damit sind bei diesen drei Rundfunkdiensten sowohl die absolute Größe als auch die räumliche Struktur der hervorgerufenen Exposition verschieden. Es wird dargelegt, wie die für die Prognose der Rundfunkversorgung verwendeten Rechenverfahren zur Modellierung der Feldstärke für die Modellierung der Exposition herangezogen und durch Kontrollmessungen validiert werden und wie trotz Wahrung der Vertraulichkeit der dabei unabdingbar zu verwendenden Senderbetriebsdaten eine unerwünschte Beeinflussung der Studienergebnisse durch die Senderbetreiber ausgeschlossen wird

    The mutational landscape of a prion-like domain

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    Insoluble protein aggregates are the hallmarks of many neurodegenerative diseases. For example, aggregates of TDP-43 occur in nearly all cases of amyotrophic lateral sclerosis (ALS). However, whether aggregates cause cellular toxicity is still not clear, even in simpler cellular systems. We reasoned that deep mutagenesis might be a powerful approach to disentangle the relationship between aggregation and toxicity. We generated >50,000 mutations in the prion-like domain (PRD) of TDP-43 and quantified their toxicity in yeast cells. Surprisingly, mutations that increase hydrophobicity and aggregation strongly decrease toxicity. In contrast, toxic variants promote the formation of dynamic liquid-like condensates. Mutations have their strongest effects in a hotspot that genetic interactions reveal to be structured in vivo, illustrating how mutagenesis can probe the in vivo structures of unstructured proteins. Our results show that aggregation of TDP-43 is not harmful but protects cells, most likely by titrating the protein away from a toxic liquid-like phase

    Autochthonous Case of Pulmonary Histoplasmosis, Switzerland.

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    In Europe, pulmonary histoplasmosis is rarely diagnosed except in travelers. We report a probable autochthonous case of severe chronic pulmonary histoplasmosis in an immunocompetent man in Switzerland without travel history outside of Europe. Diagnosis was achieved by histopathology, fungal culture, and serology, but the source of the infection remains speculative

    North-South cooperation through BIOTA: An interdisciplinary monitoring programme in arid and semi-arid southern Africa

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    Connecting disciplines in a north– South collaboration has many advantages: mutualisms evolve, synergies are created and spin-offs emerge. The BIOTA South (Biodiversity Monitoring Transect Analysis in southern Africa) programme, with its long-term vision to generate knowledge of biodiversity along a north–south transect in southern Africa, is providing opportunities for research, technology transfer and capacity building while focusing on potential solutions for critical challenges that face this environmentally vulnerable part of the subcontinen

    Time-Dependent Mechanical Response of a Composite PFSA Membrane

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    The mechanical response of a composite fuel cell membrane, made from layers of reinforced and unreinforced PFSA material, is investigated via both experimental and numerical means. First, the time-dependent mechanical properties for the reinforced layers are measured for a range of environmental and loading conditions. A three-network, viscoelastic-plastic constitutive model is developed to characterize the mechanical response of this reinforced membrane material. This constitutive model is then used in finite element simulations of a fuel cell unit (consisting of composite membrane, electrodes, gas diffusion layer and bipolar plates) where the effect of relative humidity (RH) cycling on the stress response of the composite membrane is investigated. Using numerical simulations, various layering configurations for the composite membrane and different load cases are studied. The investigation provides insight into the stress response of the membrane and suggests possible configurations that may improve the effective membrane life

    Monte-Carlo Simulations of Radiation-Induced Activation in a Fast-Neutron and Gamma- Based Cargo Inspection System

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    An air cargo inspection system combining two nuclear reaction based techniques, namely Fast-Neutron Resonance Radiography and Dual-Discrete-Energy Gamma Radiography is currently being developed. This system is expected to allow detection of standard and improvised explosives as well as special nuclear materials. An important aspect for the applicability of nuclear techniques in an airport inspection facility is the inventory and lifetimes of radioactive isotopes produced by the neutron and gamma radiation inside the cargo, as well as the dose delivered by these isotopes to people in contact with the cargo during and following the interrogation procedure. Using MCNPX and CINDER90 we have calculated the activation levels for several typical inspection scenarios. One example is the activation of various metal samples embedded in a cotton-filled container. To validate the simulation results, a benchmark experiment was performed, in which metal samples were activated by fast-neutrons in a water-filled glass jar. The induced activity was determined by analyzing the gamma spectra. Based on the calculated radioactive inventory in the container, the dose levels due to the induced gamma radiation were calculated at several distances from the container and in relevant time windows after the irradiation, in order to evaluate the radiation exposure of the cargo handling staff, air crew and passengers during flight. The possibility of remanent long-lived radioactive inventory after cargo is delivered to the client is also of concern and was evaluated.Comment: Proceedings of FNDA 201

    Threshold behavior and electro-optical properties of twisted nematic layers with weak anchoring in the tilt and twist angle

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    Analytical and numerical calculations of threshold behavior and electro-optical characteristics in twisted chiral nematic layers are presented, when weak anchoring in the tilt and twist angle of the director is assumed. An analytical expression for the effective twist angle and the Freedericksz threshold voltage is derived. In cells with bistabilities, we investigate the influence of the anchoring parameters and device parameters on the width of the hysteresis. Using the 4X4-matrix formalism of Berreman [J. Opt. Soc. Am. 62, 502 (1972)], we demonstrate the influence of the weak anchoring on the transmission-versus-voltage characteristic

    3D structure and formation of hydrothermal vent complexes at the Paleocene-Eocene transition, the Møre Basin, mid-Norwegian margin

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    Acknowledgments We thank Statoil for providing us with the PL251 (Tulipan) geophysical and geologic reports for well 6302/6- 1. We thank NORSAR for the free academic use of the SeisRox software during the modeling procedures and to Schlumberger for the free academic use of Petrel 2015. Spectral decomposition was carried out using FFA Geoteric software at the University of Aberdeen. FFA are thanked for donation of the software license to the University of Aberdeen. The authors further acknowledge the support from the Research Council of Norway through its Center of Excellence funding scheme, project 223272 (CEED), and from the MIMES project (grant no. 244155). We also gratefully acknowledge the support by the Faculty of Mathematics and Natural Sciences of the University of Oslo to TS. Clayton Grove and Craig Magee are thanked for their many insightful comments and suggestions that helped improve the paper substantially.Peer reviewedPublisher PD

    A Sucrose Solution Application to the Study of Model Biological Membranes

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    The small-angle X-ray and neutron scattering, time resolved X-ray small-angle and wide-angle diffraction coupled with differential scanning calorimetry have been applied to the investigation of unilamellar and multilamellar dimyristoylphosphatidylcholine (DMPC) vesicles in sucrose buffers with sucrose concentrations from 0 to 60%. Sucrose buffer decreased vesicle size and polydispersity and increased an X-ray contrast between phospholipid membrane and bulk solvent sufficiently. No influence of sucrose on the membrane thickness or mutual packing of hydrocarbon chains has been detected. The region of sucrose concentrations 30%-40% created the best experimental conditions for X-ray small-angle experiments with phospholipid vesicles.Comment: PDF: 10 pages, 6 figures. MS Word sours
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