Geometric frustration and quantum fluctuations may prohibit the formation of long-range ordering even at the lowest temperature, and therefore liquid-like ground states could be expected. A good example is the quantum spin liquid in frustrated magnets. Geometric frustration and quantum fluctuations can happen beyond magnetic systems. Here we propose that quantum electric-dipole liquids, analogues of quantum spin liquids, could emerge in frustrated dielectrics where antiferroelectrically coupled electric dipoles reside on a triangular lattice. The quantum paraelectric hexaferrite BaFe12O19 with geometric frustration represents a promising candidate for the proposed electric-dipole liquid. We present a series of experimental lines of evidence, including dielectric permittivity, heat capacity and thermal conductivity measured down to 66 mK, to reveal the existence of an unusual liquid-like quantum phase in BaFe12O19, characterized by itinerant low-energy excitations with a small gap. The possible quantum liquids of electric dipoles in frustrated dielectrics open up a fresh playground for fundamental physics.
RESCUE BT Trial Investigators E ndovascular treatment has been shown to significantly increase the reperfusion rate and improve the functional outcomes of patients with acute ischemic stroke due to large vessel occlusion. [1][2][3][4] However, endovascular thrombectomy has historically failed to yield successful reperfusion in approximately 30% of patients. 5 Unsuccessful reperfusion likely arises in part from mechanical thrombectomy devices causing traumatic damage to the vascular endothelium with subendothelial matrix exposure, leading to platelet activation, adhesion, and aggregation and potentially resulting in reocclusion and thromboembolic complications. 6,7 Tirofiban, a highly selective nonpeptide platelet glycoprotein IIb/IIIa inhibitor with a relatively short half-life that can reversibly prevent platelet aggregation, has been proven to reduce the risk of thrombotic complications during percutaneous coronary intervention. [8][9][10] Given the benefit of treatment of acute coronary syndromes, a growing number of studies have evaluated tirofiban as an adjunctive treatment in patients with large vessel occlusion ischemic stroke IMPORTANCE Tirofiban is a highly selective nonpeptide antagonist of glycoprotein IIb/IIIa receptor, which reversibly inhibits platelet aggregation. It remains uncertain whether intravenous tirofiban is effective to improve functional outcomes for patients with large vessel occlusion ischemic stroke undergoing endovascular thrombectomy.OBJECTIVE To assess the efficacy and adverse events of intravenous tirofiban before endovascular thrombectomy for acute ischemic stroke secondary to large vessel occlusion.DESIGN, SETTING, AND PARTICIPANTS This investigator-initiated, randomized, double-blind, placebo-controlled trial was implemented at 55 hospitals in China, enrolling 948 patients with stroke and proximal intracranial large vessel occlusion presenting within 24 hours of time last known well.
Background. There were scarce trials concerning the treatments and outcomes of proximal pancreatic stent migration. Herein, we did a retrospective study to discuss this problem from an endoscopist's point of view. Patients and Methods. From January 2009 to June 2014, patients with proximally migrated pancreatic duct stents were identified. Their clinical information was viewed. Retrieval techniques, success rates, and adverse events were analyzed. Results. A total of 36 procedures were performed in 34 patients; the median age of the patients was 53 years, with 17 males and 17 females. Eight patients' pancreatic duct stents could still be seen in the major or minor papilla and were pulled out with a snare forceps or a grasping forceps; in the remaining 28 procedures, the management was somewhat thorny; the retrieval called for several devices. Final success was achieved in 31 patients. No adverse event was observed in the process of ERCP procedures, 5 patients developed post-ERCP pancreatitis (PEP), 1 patient got infection, and 1 patient had haemorrhage. Conclusions. Endoscopic retrieval of migrated pancreatic stent is safe and less invasive; nonetheless, attention should be paid so as to reduce the incidence and degree of related adverse events, especially PEP.
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