631 research outputs found

    Coulomb effects in tunneling through a quantum dot stack

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    Tunneling through two vertically coupled quantum dots is studied by means of a Pauli master equation model. The observation of double peaks in the current-voltage characteristic in a recent experiment is analyzed in terms of the tunnel coupling between the quantum dots and the coupling to the contacts. Different regimes for the emitter chemical potential indicating different peak scenarios in the tunneling current are discussed in detail. We show by comparison with a density matrix approach that the interplay of coherent and incoherent effects in the stationary current can be fully described by this approach.Comment: 6 pages, 6 figure

    SCOPE: a scorecard for osteoporosis in Europe

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    Summary The scorecard summarises key indicators of the burden of osteoporosis and its management in each of the member states of the European Union. The resulting scorecard elements were then assembled on a single sheet to provide a unique overview of osteoporosis in Europe. Introduction The scorecard for osteoporosis in Europe (SCOPE) is an independent project that seeks to raise awareness of osteoporosis care in Europe. The aim of this project was to develop a scorecard and background documents to draw attention to gaps and inequalities in the provision of primary and secondary prevention of fractures due to osteoporosis. Methods The SCOPE panel reviewed the information available on osteoporosis and the resulting fractures for each of the 27 countries of the European Union (EU27). The information researched covered four domains: background information (e.g. the burden of osteoporosis and fractures), policy framework, service provision and service uptake e.g. the proportion of men and women at high risk that do not receive treatment (the treatment gap). Results There was a marked difference in fracture risk among the EU27. Of concern was the marked heterogeneity in the policy framework, service provision and service uptake for osteoporotic fracture that bore little relation to the fracture burden. For example, despite the wide availability of treatments to prevent fractures, in the majority of the EU27, only a minority of patients at high risk receive treatment for osteoporosis even after their first fracture. The elements of each domain in each country were scored and coded using a traffic light system (red, orange, green) and used to synthesise a scorecard. The resulting scorecard elements were then assembled on a single sheet to provide a unique overview of osteoporosis in Europe. Conclusions The scorecard will enable healthcare professionals and policy makers to assess their country’s general approach to the disease and provide indicators to inform future provision of healthcare

    Potential of a cyclone prototype spacer to improve in vitro dry powder delivery

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    Copyright The Author(s) 2013. This article is published with open access at Springerlink.com. This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are creditedPurpose: Low inspiratory force in patients with lung disease is associated with poor deagglomeration and high throat deposition when using dry powder inhalers (DPIs). The potential of two reverse flow cyclone prototypes as spacers for commercial carrierbased DPIs was investigated. Methods: Cyclohaler®, Accuhaler® and Easyhaler® were tested with and without the spacers between 30-60 Lmin-1. Deposition of particles in the next generation impactor and within the devices was determined by high performance liquid chromatography. Results: Reduced induction port deposition of the emitted particles from the cyclones was observed due to the high retention of the drug within the spacers (e.g. salbutamol sulphate (SS): 67.89 ± 6.51 % at 30 Lmin-1 in Cheng 1). Fine particle fractions of aerosol as emitted from the cyclones were substantially higher than the DPIs alone. Moreover, the aerodynamic diameters of particles emitted from the cyclones were halved compared to the DPIs alone (e.g. SS from the Cyclohaler® at 4 kPa: 1.08 ± 0.05 μm vs. 3.00 ± 0.12 μm, with and without Cheng 2, respectively) and unaltered with increased flow rates. Conclusion: This work has shown the potential of employing a cyclone spacer for commercial carrier-based DPIs to improve inhaled drug delivery.Peer reviewe

    Bragg coherent x-ray diffractive imaging of a single indium phosphide nanowire

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    Three-dimensional (3D) Bragg coherent x-ray diffractive imaging (CXDI) with a nanofocused beam was applied to quantitatively map the internal strain field of a single indium phosphide nanowire. The quantitative values of the strain were obtained by pre-characterization of the beam profile with transmission ptychography on a test sample. Our measurements revealed the 3D strain distribution in a region of 150 nm below the catalyst Au particle. We observed a slight gradient of the strain in the range of ±0.6% along the [111] growth direction of the nanowire. We also determined the spatial resolution in our measurements to be about 10 nm in the direction perpendicular to the facets of the nanowire. The CXDI measurements were compared with the finite element method simulations and show a good agreement with our experimental results. The proposed approach can become an effective tool for in operando studies of the nanowires

    You turn me cold: evidence for temperature contagion

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    Introduction During social interactions, our own physiological responses influence those of others. Synchronization of physiological (and behavioural) responses can facilitate emotional understanding and group coherence through inter-subjectivity. Here we investigate if observing cues indicating a change in another's body temperature results in a corresponding temperature change in the observer. Methods Thirty-six healthy participants (age; 22.9±3.1 yrs) each observed, then rated, eight purpose-made videos (3 min duration) that depicted actors with either their right or left hand in visibly warm (warm videos) or cold water (cold videos). Four control videos with the actors' hand in front of the water were also shown. Temperature of participant observers' right and left hands was concurrently measured using a thermistor within a Wheatstone bridge with a theoretical temperature sensitivity of <0.0001°C. Temperature data were analysed in a repeated measures ANOVA (temperature × actor's hand × observer's hand). Results Participants rated the videos showing hands immersed in cold water as being significantly cooler than hands immersed in warm water, F(1,34) = 256.67, p0.1). There was however no evidence of left-right mirroring of these temperature effects p>0.1). Sensitivity to temperature contagion was also predicted by inter-individual differences in self-report empathy. Conclusions We illustrate physiological contagion of temperature in healthy individuals, suggesting that empathetic understanding for primary low-level physiological challenges (as well as more complex emotions) are grounded in somatic simulation

    Macrophages promote angiogenesis in human breast tumour spheroids in vivo

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    An in vivo model has been established to study the role of macrophages in the initiation of angiogenesis by human breast tumour spheroids in vivo. The extent of the angiogenic response induced by T47D spheroids implanted into the dorsal skinfold chamber in nude mice was measured in vivo and compared to that induced by spheroids infiltrated with human macrophages prior to implantation. Our results indicate that the presence of macrophages in spheroids resulted in at least a three-fold upregulation in the release of vascular endothelial growth factor (VEGF) in vitro when compared with spheroids composed only of tumour cells. The angiogenic response measured around the spheroids, 3 days after in vivo implantation, was significantly greater in the spheroids infiltrated with macrophages. The number of vessels increased (macrophages vs no macrophages 34±1.9 vs 26±2.5, P<0.01), were shorter in length (macrophages vs no macrophages 116±4.92 vs 136±6.52, P<0.008) with an increased number of junctions (macrophages vs no macrophages 14±0.93 vs 11±1.25, P<0.025) all parameters indicative of new vessel formation. This is the first study to demonstrate a role for macrophages in the initiation of tumour angiogenesis in vivo

    The March 11th, 2011, M 9.0 earthquake offshore Honshu island (Japan): a synthesis of the Tohoku-Oki INGV Team research activities

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    On March 11th, 2011 (at 05:46:23 UTC) a megaearthquake (M 9.0) occurred near the NE coast of Honshu island ( Japan), originated near the subduction plate boundary between the Pacific and the North America plates. The epicenter has been located at about 130 km East of Sendai city, at a depth of about 32 km. This seismic event has been followed by a devastating tsunami. The location, the geometric parameters, the focal mechanism, are in agreement with the occurrence of the earthquake along the subduction plate boundary. The initial seismological analysis indicated that a surface of about 300 km x 150 km over the fault moved upwards of 30-40 m. The Tohoku-Oki INGV Team has made available a wide and multisciplinary expertise to investigate the different scientific issues concerning the earthquake. Indeed from Seismology to Geomorphology, from Remote Sensing to GPS, from Tsunami to Source Modeling the INGV Team has completed a wide range of analysis, obtaining relevant outcomes that are summarized in this work.Published1-272T. Tettonica attivaN/A or not JCRope
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