46 research outputs found

    Micro Structured Sensors for Neutron Detection

    Get PDF
    The shortage of 3He gas, identified as a problem several years ago, initiated research into alternative neutron detectors for various applications. One such technology is the microstructured semiconductor neutron detector (MSND). These compact detectors have microstructures etched deeply into the substrates that are subsequently backfilled with neutron reactive material. Single sided devices typically have thermal neutron detection efficiencies exceeding 30%, while double sided microstructured semiconductor neutron detectors (DS-MSND) have yielded \u3e69% thermal neutron detection efficiency. Both MSNDs and DS-MSNDs have been integrated into compact low-noise and low-power electronics modules. Dosimetry calculations indicate that these detectors can be used as active wearable neutron dosimeters. A discussion on the physics, performance and instrumentation of these MSNDs will be presented. The radiation environment in a nuclear reactor precludes the use of semiconductor detectors for in-core sensors, leading to the invention of another miniaturized neutron detector, the micro- pocket fission detector (MPFD). The detectors were developed for real time reactor power monitoring and also for pulse tracking for power excursion experiments. These miniaturized fission chambers have gas pockets on the order of 1 mm3 with a small concentration of uranium electrodeposited inside the gas chamber. The detectors are composed of radiation hard materials and assembled without adhesives. The small geometries can be assembled in arrays to transmit reactor power at various locations. Stable device operation was confirmed by testing under steady-state reactor conditions. Reactor power transients were observed in real-time. Design details and performance of MPFDs will be presented

    (Metallo)porphyrins for potential materials science applications

    Get PDF
    The bottom-up approach to replace existing devices by molecular-based systems is a subject that attracts permanently increasing interest. Molecular-based devices offer not only to miniaturize the device further, but also to benefit from advanced functionalities of deposited molecules. Furthermore, the molecules itself can be tailored to allow via their self-assembly the potential fabrication of devices with an application potential, which is still unforeseeable at this time. Herein, we review efforts to use discrete (metallo)porphyrins for the formation of (sub)monolayers by surface-confined polymerization, of monolayers formed by supramolecular recognition and of thin films formed by sublimation techniques. Selected physical properties of these systems are reported as well. The application potential of those ensembles of (metallo)porphyrins in materials science is discussed

    Optical properties and electrical transport of thin films of terbium(III) bis(phthalocyanine) on cobalt

    Get PDF
    The optical and electrical properties of terbium(III) bis(phthalocyanine) (TbPc2) films on cobalt substrates were studied using variable angle spectroscopic ellipsometry (VASE) and current sensing atomic force microscopy (cs-AFM). Thin films of TbPc2 with a thickness between 18 nm and 87 nm were prepared by organic molecular beam deposition onto a cobalt layer grown by electron beam evaporation. The molecular orientation of the molecules on the metallic film was estimated from the analysis of the spectroscopic ellipsometry data. A detailed analysis of the AFM topography shows that the TbPc2 films consist of islands which increase in size with the thickness of the organic film. Furthermore, the cs-AFM technique allows local variations of the organic film topography to be correlated with electrical transport properties. Local current mapping as well as local I-V spectroscopy shows that despite the granular structure of the films, the electrical transport is uniform through the organic films on the microscale. The AFM-based electrical measurements allow the local charge carrier mobility of the TbPc2 thin films to be quantified with nanoscale resolution

    Tuning the magneto-optical response of TbPc2 single molecule magnets by the choice of the substrate

    Get PDF
    In this work, we investigated the magneto-optical response of thin films of TbPc2 on substrates which are relevant for (spin) organic field effect transistors (SiO2) or vertical spin valves (Co) in order to explore the possibility of implementing TbPc2 in magneto-electronic devices, the functionality of which includes optical reading. The optical and magneto-optical properties of TbPc2 thin films prepared by organic molecular beam deposition (OMBD) on silicon substrates covered with native oxide were investigated by variable angle spectroscopic ellipsometry (VASE) and magneto-optical Kerr effect (MOKE) spectroscopy at room temperature. The magneto-optical activity of the TbPc2 films can be significantly enhanced by one to two orders of magnitude upon changing the molecular orientation (from nearly standing molecules on SiO2/Si substrates to nearly lying molecules on perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) templated SiO2/Si substrates) or by using metallic ferromagnetic substrates (Co)

    The management of acute venous thromboembolism in clinical practice. Results from the European PREFER in VTE Registry

    Get PDF
    Venous thromboembolism (VTE) is a significant cause of morbidity and mortality in Europe. Data from real-world registries are necessary, as clinical trials do not represent the full spectrum of VTE patients seen in clinical practice. We aimed to document the epidemiology, management and outcomes of VTE using data from a large, observational database. PREFER in VTE was an international, non-interventional disease registry conducted between January 2013 and July 2015 in primary and secondary care across seven European countries. Consecutive patients with acute VTE were documented and followed up over 12 months. PREFER in VTE included 3,455 patients with a mean age of 60.8 ± 17.0 years. Overall, 53.0 % were male. The majority of patients were assessed in the hospital setting as inpatients or outpatients (78.5 %). The diagnosis was deep-vein thrombosis (DVT) in 59.5 % and pulmonary embolism (PE) in 40.5 %. The most common comorbidities were the various types of cardiovascular disease (excluding hypertension; 45.5 %), hypertension (42.3 %) and dyslipidaemia (21.1 %). Following the index VTE, a large proportion of patients received initial therapy with heparin (73.2 %), almost half received a vitamin K antagonist (48.7 %) and nearly a quarter received a DOAC (24.5 %). Almost a quarter of all presentations were for recurrent VTE, with >80 % of previous episodes having occurred more than 12 months prior to baseline. In conclusion, PREFER in VTE has provided contemporary insights into VTE patients and their real-world management, including their baseline characteristics, risk factors, disease history, symptoms and signs, initial therapy and outcomes

    Safety and effectiveness of a fixed-dose combination of olmesartan, amlodipine, and hydrochlorothiazide in clinical practice

    No full text
    Peter Bramlage,1 Eva-Maria Fronk,2 Wolf-Peter Wolf,3 Rüdiger Smolnik,3 Gemma Sutton,1 Roland E Schmieder4 1Institut für Pharmakologie und präventive Medizin, Mahlow, Germany; 2Daiichi Sankyo Europe GmbH, Munich, Germany; 3Daiichi Sankyo Deutschland GmbH, Munich, Germany; 4Abteilung für Nephrologie und Hypertensiologie, Universitätsklinikum Erlangen, Erlangen, Germany Background: Clinical trials indicate that the use of fixed-dose combinations (FDCs) is associated with a higher level of treatment adherence and prolonged blood pressure (BP) control. The aim of this study was to document the safety and effectiveness of the FDC olmesartan/amlodipine/hydrochlorothiazide in patients with essential hypertension in clinical practice. Methods: This multicenter, prospective, 24-week, noninterventional study enrolled 5,831 patients from primary care offices in Germany and Austria. Inclusion criteria were a diagnosis of essential hypertension and newly initiated treatment with the FDC. Results: The mean age of patients was 63.5 years, almost 50% of patients had a time since diagnosis of essential hypertension of over 5 years, and approximately 70% of patients had at least one cardiovascular risk factor, including 29.4% of patients with diabetes mellitus. Following approximately 24 weeks of treatment, the mean reduction in systolic/diastolic BP was 29.0/14.0 mmHg, a BP response was observed by 94.2% of patients, and a target BP of <140/90 mmHg was attained in 67.5% of patients. At least one adverse drug reaction (ADR) was experienced by 1.2% of patients, with the most common being peripheral edema. Subanalyses demonstrated that the following factors did not have a significant influence on the ADR rate: age (<65 years versus ≥65 years), diabetes mellitus (no/yes), cardiovascular risk (low/high), and concomitant medication (no/yes). Conclusion: This study demonstrates that in clinical practice, treatment with the three-drug combination as an FDC tablet resulted in a very high proportion of patients with a BP response and control, accompanied by a very low rate of ADRs. Keywords: hypertension, clinical practice, fixed-dose combination, blood pressure, adverse drug reaction
    corecore