4,241 research outputs found

    Anisotropic strains, metal-insulator transition, and magnetoresistance of La0.7_{0.7}Ca0.3_{0.3}MnO3_{3} films

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    Thin films of perovskite manganite La0.7_{0.7}Ca0.3_{0.3}MnO3_{3} were grown epitaxially on various substrates by either the pulsed laser deposition method or laser molecular beam epitaxy. The substrates change both the volume and symmetry of the unit cell of the films. It is revealed that the symmetry as well as the volume of the unit cell have strong influence on the metal-insulator transition temperature and the size of magnetoresistance.Comment: 6 pages, 3 figure

    Weakening of the stratospheric polar vortex by Arctic sea-ice loss

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    Successive cold winters of severely low temperatures in recent years have had critical social and economic impacts on the mid-latitude continents in the Northern Hemisphere. Although these cold winters are thought to be partly driven by dramatic losses of Arctic sea-ice, the mechanism that links sea-ice loss to cold winters remains a subject of debate. Here, by conducting observational analyses and model experiments, we show how Arctic sea-ice loss and cold winters in extra-polar regions are dynamically connected through the polar stratosphere. We find that decreased sea-ice cover during early winter months (November-December), especially over the Barents-Kara seas, enhances the upward propagation of planetary-scale waves with wavenumbers of 1 and 2, subsequently weakening the stratospheric polar vortex in mid-winter (January-February). The weakened polar vortex preferentially induces a negative phase of Arctic Oscillation at the surface, resulting in low temperatures in mid-latitudes.open11167174Ysciescopu

    Influence of noise sensitivity on physiological responses to floor impact sounds

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    This study investigated the changes in physiological responses to floor impact sounds under a laboratory condition. A total of 34 normal-hearing participants took part in the experiment and were categorised into two groups with low and high noise-sensitivity scores. The participants were exposed to five-minute floor impact sounds produced by a standard impact noise source (an impact ball) and a real impact noise source (human footsteps). For comparison, road traffic noise was used as a reference stimulus. After being exposed to each stimulus, the participants were asked to rate annoyance. During the experiments, heart rate (HR), electrodermal activity (EDA), and respiratory rate (RR) were measured. Annoyance was found to be influenced by noise level, noise source, and noise sensitivity. All physiological responses were found to be changed significantly due to noise exposure. HR decelerated, EDA decreased, and RR decelerated for five minutes of noise exposure. The physiological responses were significantly influenced by noise sensitivity. However, there were no significant effects of noise level or noise source on the physiological responses

    Intensified Arctic warming under greenhouse warming by vegetation–atmosphere–sea ice interaction

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    Observations and modeling studies indicate that enhanced vegetation activities over high latitudes under an elevated CO2 concentration accelerate surface warming by reducing the surface albedo. In this study, we suggest that vegetation-atmosphere-sea ice interactions over high latitudes can induce an additional amplification of Arctic warming. Our hypothesis is tested by a series of coupled vegetation-climate model simulations under 2xCO(2) environments. The increased vegetation activities over high latitudes under a 2xCO(2) condition induce additional surface warming and turbulent heat fluxes to the atmosphere, which are transported to the Arctic through the atmosphere. This causes additional sea-ice melting and upper-ocean warming during the warm season. As a consequence, the Arctic and high-latitude warming is greatly amplified in the following winter and spring, which further promotes vegetation activities the following year. We conclude that the vegetation-atmosphere-sea ice interaction gives rise to additional positive feedback of the Arctic amplification.open1188sciescopu

    Complete gate control of supercurrent in graphene p-n junctions

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    In a conventional Josephson junction of graphene, the supercurrent is not turned off even at the charge neutrality point, impeding further development of superconducting quantum information devices based on graphene. Here we fabricate bipolar Josephson junctions of graphene, in which a p-n potential barrier is formed in graphene with two closely spaced superconducting contacts, and realize supercurrent ON/OFF states using electrostatic gating only. The bipolar Josephson junctions of graphene also show fully gate-driven macroscopic quantum tunnelling behaviour of Josephson phase particles in a potential well, where the confinement energy is gate tuneable. We suggest that the supercurrent OFF state is mainly caused by a supercurrent dephasing mechanism due to a random pseudomagnetic field generated by ripples in graphene, in sharp contrast to other nanohybrid Josephson junctions. Our study may pave the way for the development of new gate-tuneable superconducting quantum information devices.open114344sciescopu

    The clinical usefulness of initial serum procalcitonin as an aggravation predictor in a hepatobiliary tract infection at emergency department

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    Background and Objectives: The ability to predict future clinical deterioration early in patients who present to an emergency care center with a hepatobiliary tract infection is difficult. We studied the clinical usefulness of the initial serum levels of procalcitonin in a hepatobiliary tract infection as an indicator for predicting aggravation in the early stages.Methods: Of the patients who presented with the clinical symptoms of a hepatobiliary tract infection, 99 were diagnosed with a hepatobiliary tract infection by imaging studies and subsequently enrolled in the study. Laboratory tests were obtained in the early stage of disease after presentation to an emergency care center. We assessed and compared the serum levels of many early inflammatory markers (white blood cell [WBC] counts, C‑reactive protein and procalcitonin) between patients whose symptoms were initially stable upon arrival to an emergency care center but then deteriorated to, those whose symptoms remained consistently stable. Thus, we examined if the above serum markers are useful in predicting the possibility of future symptom aggravation.Results: Of a total of 99 patients, 27 were assigned to the symptom aggravation group. The serum levels of WBC counts and C‑reactive protein in the aggravation group were elevated. However, the median value (interquartile range) of procalcitonin was relatively increased at 2.28 (0.41–7.84 ng/ml), demonstrating a significant difference.Conclusions: In conclusion, initial serum levels of procalcitonin might be used as an indicator for aggravation in patients with hepatobiliary tract infection at the emergency department, even though there is hemodynamic stability.Key words: Hepatobiliary tract, infection, procalcitoni

    Recent advances in osmotic energy generation via pressure-retarded osmosis (PRO): A review

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    © 2015 by the authors. Global energy consumption has been highly dependent on fossil fuels which cause severe climate change and, therefore, the exploration of new technologies to produce effective renewable energy plays an important role in the world. Pressure-retarded osmosis (PRO) is one of the promising candidates to reduce the reliance on fossil fuels by harnessing energy from the salinity gradient between seawater and fresh water. In PRO, water is transported though a semi-permeable membrane from a low-concentrated feed solution to a high-concentrated draw solution. The increased volumetric water flow then runs a hydro-turbine to generate power. PRO technology has rapidly improved in recent years; however, the commercial-scale PRO plant is yet to be developed. In this context, recent developments on the PRO process are reviewed in terms of mathematical models, membrane modules, process designs, numerical works, and fouling and cleaning. In addition, the research requirements to accelerate PRO commercialization are discussed. It is expected that this article can help comprehensively understand the PRO process and thereby provide essential information to activate further research and development

    Plasmonic Nano-Rotamers with Programmable Polarization-Resolved Coloration

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    3D-shaped artificial Mg nano-rotamers with a programmable dihedral angle between two plasmonic arms, designed to exhibit both programmable linear and circular polarization properties, are presented. The nanoscale physical shadow growth technique offers precise control over the angular alignment in these nanostructures with 1° angular precision, thus controlling their symmetry from achiral C2v and C2h to chiral C2. As a result, they give rise to a wide range of polarization-resolved coloration, spanning from invisible to visible colors with 46% transmission contrast for linear polarization while exhibiting 0.08 g-factor in visible for circular polarization. These nano-rotamers hold great potential for various applications in adaptive photonic filters, memory, and anticounterfeiting devices, benefiting from their tunable plasmonic properties

    TRPCs: Influential Mediators in Skeletal Muscle

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    Ca2+ itself or Ca2+-dependent signaling pathways play fundamental roles in various cellular processes from cell growth to death. The most representative example can be found in skeletal muscle cells where a well-timed and adequate supply of Ca2+ is required for coordinated Ca2+-dependent skeletal muscle functions, such as the interactions of contractile proteins during contraction. Intracellular Ca2+ movements between the cytosol and sarcoplasmic reticulum (SR) are strictly regulated to maintain the appropriate Ca2+ supply in skeletal muscle cells. Added to intracellular Ca2+ movements, the contribution of extracellular Ca2+ entry to skeletal muscle functions and its significance have been continuously studied since the early 1990s. Here, studies on the roles of channel proteins that mediate extracellular Ca2+ entry into skeletal muscle cells using skeletal myoblasts, myotubes, fibers, tissue, or skeletal muscle-originated cell lines are reviewed with special attention to the proposed functions of transient receptor potential canonical proteins (TRPCs) as store-operated Ca2+ entry (SOCE) channels under normal conditions and the potential abnormal properties of TRPCs in muscle diseases such as Duchenne muscular dystrophy (DMD)
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