3,249 research outputs found

    Arterial embolisation to control haemorrhage following colonoscopic polypectomy

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    Specific heat study of the Na(0.3)CoO(2).1.3H(2)O superconductor: influence of the complex chemistry

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    We report results of specific heat measurements on polycrystalline samples of the layered superconductor, Na(0.3)CoO(2).1.3H(2)O. The electronic contribution to the specific heat, gamma, is found to be 12.2 mJ/mol-K2. The feature at the superconducting transition is rather sharp, becoming broad and strongly suppressed in an applied magnetic field. The data indicate a residual normal state electronic specific heat at low temperatures, implying that there is a sizable population of normal state electrons in the samples even below Tc. Inhomogeneity in the Na content, to which the superconducting state is exquisitely sensitive, appears to be the most likely explanation for these results. These results further indicate that special sample handling is required for an accurate characterization of the superconducting state in this material.Comment: publication information adde

    Chemical Instability of the Cobalt Oxyhydrate Superconductor under Ambient Conditions

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    The layered sodium cobalt oxyhydrate superconductor Na0.3CoO2*1.4H2O is shown through X-ray diffraction and thermogravimetric studies to be one of a series of hydrated phases of Na0.3CoO2. Further, it is shown that the material is exceptionally sensitive to both temperature and humidity near ambient conditions, easily dehydrating to a non-superconducting lower hydrate. The observation of this stable lower hydrate with c=13.8 angstroms implies that the superconductivity turns on in this system between CoO2 layer spacings of 6.9 and 9.9 angstroms at nominally constant chemical doping.Comment: 10 pages and 4 figure

    Arrival time and magnitude of airborne fission products from the Fukushima, Japan, reactor incident as measured in Seattle, WA, USA

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    We report results of air monitoring started due to the recent natural catastrophe on 11 March 2011 in Japan and the severe ensuing damage to the Fukushima Dai-ichi nuclear reactor complex. On 17-18 March 2011, we registered the first arrival of the airborne fission products 131-I, 132-I, 132-Te, 134-Cs, and 137-Cs in Seattle, WA, USA, by identifying their characteristic gamma rays using a germanium detector. We measured the evolution of the activities over a period of 23 days at the end of which the activities had mostly fallen below our detection limit. The highest detected activity amounted to 4.4 +/- 1.3 mBq/m^3 of 131-I on 19-20 March.Comment: 7 pages, 5 figures, published in Journal of Environmental Radioactivit

    Extracellular vesicles in acute respiratory distress syndrome: Understanding protective and harmful signaling for the development of new therapeutics

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    Acute respiratory distress syndrome (ARDS) is a severe respiratory condition characterized by increased lung permeability, hyper-inflammatory state, and fluid leak into the alveolar spaces. ARDS is a heterogeneous disease, with multiple direct and indirect causes that result in a mortality of up to 40%. Due to the ongoing Covid-19 pandemic, its incidence has increased up to ten-fold. Extracellular vesicles (EVs) are small liposome-like particles that mediate intercellular communication and play a major role in ARDS pathophysiology. Indeed, they participate in endothelial barrier dysfunction and permeability, neutrophil, and macrophage activation, and also in the development of a hypercoagulable state. A more thorough understanding of the variegated and cell-specific functions of EVs may lead to the development of safe and effective therapeutics. In this review, we have collected evidence of EVs role in ARDS, revise the main mechanisms of production and internalization and summarize the current therapeutical approaches that have shown the ability to modulate EV signaling

    Short communication: Phenotypic and genetic diversity of wild Lactococcus lactis isolated from traditional Pecorino cheeses of Tuscany

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    Wild Lactococcus lactis isolates from traditional Pecorino cheeses in 4 regions of Tuscany were isolated and characterized to evaluate the diversity of autochthonous lactococci. Sixty strains of Lactococcus were clustered by the results of carbohydrate utilization and diagnostic enzyme activity. Twenty-one unique strains were then chosen for characterization of salt and temperature tolerance, as well as acidification and proteolytic activity in milk. Genetic analysis of these strains was performed via 16S ribosomal DNA sequencing and multilocus sequence typing (MLST) to elucidate diversity relative to their location of origin. Phylogenetic analysis showed distinct clustering by region within organism subspecies, and phenotypic properties demonstrated concomitant trends. Multilocus sequence typing thus allowed for the regional distinction of isolates separate from those of previous works, supporting the concept that distinctive regional qualities of cheeses are strongly influenced by microbial ecology

    Nested Codes for Constrained Memory and for Dirty Paper

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    Dirty paper coding are relevant for wireless networks, multiuser channels, and digital watermarking. We show that the problem of dirty paper is essentially equivalent to some classes of constrained memories, and we explore the binary so-called nested codes, which are used for efficient coding and error-correction on such channels and memories. © Springer-Verlag Berlin Heidelberg 2006

    Study on initial geometry fluctuations via participant plane correlations in heavy ion collisions: part II

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    Further investigation of the participant plane correlations within a Glauber model framework is presented, focusing on correlations between three or four participant planes of different order. A strong correlation is observed for cos(2Φ2+3Φ35Φ5)\cos(2\Phi_{2}^*+3\Phi_{3}^*-5\Phi_{5}^*) which is a reflection of the elliptic shape of the overlap region. The correlation between the corresponding experimental reaction plane angles can be easily measured. Strong correlations of similar geometric origin are also observed for cos(2Φ2+4Φ46Φ6)\cos(2\Phi_{2}^*+4\Phi_{4}^*-6\Phi_{6}^*), cos(2Φ23Φ34Φ4+5Φ5)\cos(2\Phi_2^*-3\Phi_3^*-4\Phi_4^*+5\Phi_5^*), cos(6Φ2+3Φ34Φ45Φ5)\cos(6\Phi_2^*+3\Phi_3^*-4\Phi_4^*-5\Phi_5^*), cos(Φ12Φ23Φ3+4Φ4)\cos(\Phi_1^*-2\Phi_2^*-3\Phi_3^*+4\Phi_4^*), cos(Φ1+6Φ23Φ34Φ4)\cos(\Phi_1^*+6\Phi_2^*-3\Phi_3^*-4\Phi_4^*), and cos(Φ1+2Φ2+3Φ36Φ6)\cos(\Phi_1^*+2\Phi_2^*+3\Phi_3^*-6\Phi_6^*), which are also measurable. Experimental measurements of the corresponding reaction plane correlators in heavy ion collisions at RHIC and the LHC may improve our understanding of the physics underlying the measured higher order flow harmonics.Comment: 5 pages, 5 figure

    Influence of temperature gradients on tunnel junction thermometry below 1 K: cooling and electron-phonon coupling

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    We have studied thermal gradients in thin Cu and AlMn wires, both experimentally and theoretically. In the experiments, the wires were Joule heated non-uniformly at sub-Kelvin temperatures, and the resulting temperature gradients were measured using normal metal-insulator-superconducting tunnel junctions. The data clearly shows that even in reasonably well conducting thin wires with a short (10μ\sim 10 \mum) non-heated portion, significant temperature differences can form. In most cases, the measurements agree well with a model which includes electron-phonon interaction and electronic thermal conductivity by the Wiedemann-Franz law.Comment: J. Low Temp. Phys. in pres
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