886 research outputs found

    Higher superconducting transition temperature by breaking the universal pressure relation

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    By investigating the bulk superconducting state via dc magnetization measurements, we have discovered a common resurgence of the superconductive transition temperatures (Tcs) of the monolayer Bi2Sr2CuO6+{\delta} (Bi2201) and bilayer Bi2Sr2CaCu2O8+{\delta} (Bi2212) to beyond the maximum Tcs (Tc-maxs) predicted by the universal relation between Tc and doping (p) or pressure (P) at higher pressures. The Tc of under-doped Bi2201 initially increases from 9.6 K at ambient to a peak at ~ 23 K at ~ 26 GPa and then drops as expected from the universal Tc-P relation. However, at pressures above ~ 40 GPa, Tc rises rapidly without any sign of saturation up to ~ 30 K at ~ 51 GPa. Similarly, the Tc for the slightly overdoped Bi2212 increases after passing a broad valley between 20-36 GPa and reaches ~ 90 K without any sign of saturation at ~ 56 GPa. We have therefore attributed this Tc-resurgence to a possible pressure-induced electronic transition in the cuprate compounds due to a charge transfer between the Cu 3d_(x^2-y^2 ) and the O 2p bands projected from a hybrid bonding state, leading to an increase of the density of states at the Fermi level, in agreement with our density functional theory calculations. Similar Tc-P behavior has also been reported in the trilayer Br2Sr2Ca2Cu3O10+{\delta} (Bi2223). These observations suggest that higher Tcs than those previously reported for the layered cuprate high temperature superconductors can be achieved by breaking away from the universal Tc-P relation through the application of higher pressures.Comment: 13 pages, including 5 figure

    CR3 and Dectin-1 Collaborate in Macrophage Cytokine Response through Association on Lipid Rafts and Activation of Syk-JNK-AP-1 Pathway

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    Copyright: © 2015 Huang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited Acknowledgments We are grateful to the Second Core Laboratory of Research Core Facility at the National Taiwan University Hospital for confocal microscopy service and providing ultracentrifuge. We thank Dr. William E. Goldman (University of North Carolina, Chapel Hill, NC) for kindly providing WT and ags1-null mutant of H. capsulatum G186A. Funding: This work is supported by research grants 101-2320-B-002-030-MY3 from the Ministry of Science and Technology (http://www.most.gov.tw) and AS-101-TP-B06-3 from Academia Sinica (http://www.sinica.edu.tw) to BAWH. GDB is funded by research grant 102705 from Welcome Trust (http://www.wellcome.ac.uk). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

    Complete Remission of Pancreatic Pseudoaneurysm Rupture with Arterial Embolization in a Patient with Poor Risk for Surgery: A Case Report

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    Pancreatic pseudoaneurysm is a rare vascular complication of chronic pancreatitis resulting from erosion of the pancreatic or peripancreatic artery into a pseudocyst that is identified as a pulsating vascular malformation which may lead to lethal complications if left untreated. Many publications in the literature consider angiography as the first step in the management of pancreatic pseudoaneurysm to stabilize the patient's critical condition; it should be followed by surgical intervention as the definite treatment. We report a rare case of pancreatic pseudoaneurysm rupture with hemodynamic embarrassment in a critical patient with multiple comorbid conditions and poor risk for surgery who responded dramatically to angiographic management as a single therapeutic modality without further surgical intervention. The results observed in our patient suggest that pancreatic pseudoaneurysm may be successfully managed with angiography only and that not all cases require surgical intervention. This is particularly relevant in critically ill patients in whom surgical intervention would be unfeasible

    Pressure-induced polarization reversal in multiferroic YMn2O5YMn_2O_5

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    The low-temperature ferroelectric polarization of multiferroic YMn2O5YMn_2O_5 is completely reversed at a critical pressure of 10 kbar and the phase transition from the incommensurate to the commensurate magnetic phase is induced by pressures above 14 kbar. The high-pressure data correlate with thermal expansion measurements indicating a significant lattice strain at the low-temperature transition into the incommensurate phase. The results support the exchange striction model for the ferroelectricity in multiferroic RMn2O5RMn_2O_5 compounds and they show the importance of magnetic frustration as well as the spin-lattice coupling

    Nanoscale surface element identification and dopant homogeneity in the high-TcT_{c} superconductor PrxCa1xFe2As2Pr_xCa_{1−x}Fe_2As_2

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    We use scanning tunneling microscopy to determine the surface structure and dopant distribution in PrxCa1xFe2As2Pr_xCa_{1−x}Fe_2As_2, the highest-Tc member of the 122 family of iron-based superconductors. We identify the cleaved surface termination by mapping the local tunneling barrier height, related to the work function. We image the individual Pr dopants responsible for superconductivity, and show that they do not cluster, but in fact repel each other at short length scales. We therefore suggest that the low volume fraction high-Tc superconducting phase is unlikely to originate from Pr inhomogeneity.Physic
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