89 research outputs found

    Polarity engineering in polycrystalline ZnO by inversion boundaries

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    Two distinctive polarity-engineered microstructures were obtained in polycrystalline ZnO ceramics by inducing two different types of inversion boundaries (IBs) inside individual grains to examine the effect of the different polarities on the varistor performances. The presence of head-to-head IBs induced by the addition of Sb and tail-to-tail IBs by doping Ti was directly confirmed by the characteristic geometry of the chemical etch pits. It was proposed that a consequent polarity on the grain boundary planes, which are affected by the presence of head-to-head IBs is crucial in exhibiting the superior performance of ZnO varistors.open2

    Microfluidic system for monitoring temporal variations of hemorheological properties and platelet adhesion in LPS-injected rats

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    Sepsis causes multiple organs failures and eventually death. Changes in blood constituents due to sepsis lead to alterations in hemorheological properties, and cell adhesiveness. In this study, a new microfluidic system is proposed to measure temporal variations in biophysical properties of blood after injecting lipopolysaccharide (LPS) into a rat extracorporeal model under ex vivo condition. To measure blood viscosity, the interfacial line between blood and a reference fluid is formed in a Y-shaped channel. Based on the relation between interfacial width and pressure ratio, the temporal variation in blood viscosity is estimated. Optical images of blood flows are analyzed by decreasing flow rate for examination of red blood cell (RBC) aggregation. Platelets initiated by shear acceleration around the stenosis adhere to the post-stenosed region. By applying a correlation map that visualizes the decorrelation of the streaming blood flow, the area of adhered platelets can be quantitatively attained without labeling of platelets. To assess sepsis inflammation, conventional biomarkers (PCT and IL-8) are also monitored. The increasing tendency for blood viscosity, RBC aggregation, platelet adhesion, and septic biomarkers are observed after LPS injection. This microfluidic system would be beneficial for monitoring the changes in hemorheological properties and platelet activation caused by sepsis.116Ysciescopu

    MicroRNA-150 modulates intracellular Ca2+ levels in naïve CD8+ T cells by targeting TMEM20

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    Regulation of intracellular Ca2+ signaling is a major determinant of CD8+ T cell responsiveness, but the mechanisms underlying this regulation of Ca2+ levels, especially in naïve CD8+ T cells, are not fully defined. Here, we showed that microRNA-150 (miR-150) controls intracellular Ca2+ levels in naïve CD8+ T cells required for activation by suppressing TMEM20, a negative regulator of Ca2+ extrusion. miR-150 deficiency increased TMEM20 expression, which resulted in increased intracellular Ca2+ levels in naïve CD8+ T cells. The subsequent increase in Ca2+ levels induced expression of anergy-inducing genes, such as Cbl-b, Egr2, and p27, through activation of NFAT1, as well as reduced cell proliferation, cytokine production, and the antitumor activity of CD8+ T cells upon antigenic stimulation. The anergy-promoting molecular milieu and function induced by miR-150 deficiency were rescued by reinstatement of miR-150. Additionally, knockdown of TMEM20 in miR-150-deficient naïve CD8+ T cells reduced intracellular Ca2+ levels. Our findings revealed that miR-150 play essential roles in controlling intracellular Ca2+ level and activation in naïve CD8+ T cells, which suggest a mechanism to overcome anergy induction by the regulation of intracellular Ca2+ levels115Ysciescopu

    Mechanochemical Synthesis and Rapid Consolidation of Nanocrystalline 3NiAl- Al

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    Nanopowders of 3NiAl and Al2O3 were synthesized from 3NiO and 5Al powders by high-energy ball milling. Nanocrystalline Al2O3 reinforced composite was consolidated by high-frequency induction-heated sintering within 3 minutes from mechanochemically synthesized powders of Al2O3 and 3NiAl. The advantage of this process is that it allows very quick densification to near theoretical density and inhibition grain growth. Nanocrystalline materials have received much attention as advanced engineering materials with improved physical and mechanical properties. The relative density of the composite was 97%. The average Vickers hardness and fracture toughness values obtained were 804 kg/mm2 and 7.5 MPa⋅m1/2, respectively

    Angiographic and clinical comparison of novel Orsiro Hybrid sirolimus-eluting stents and Resolute Integrity zotarolimus-eluting stents in all-comers with coronary artery disease (ORIENT trial): study protocol for a randomized controlled trial

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    Trial registration : Clinicaltrials.gov NCT01826552Background : The Orsiro Hybrid sirolimus-eluting stent is a newly developed third-generation drug-eluting stent, featuring a unique dual-polymer mix. An active bioabsorbable polymer delivers the anti-proliferative drug, sirolimus, via controlled release, while a passive biocompatible polymeric coating shields the metallic strut from surrounding tissue, preventing interaction. To date, the Orsiro Hybrid sirolimus-eluting stent has excelled in terms of late lumen loss at 9 months in a first-in-man single-arm trial. However, the efficacy and safety data for Orsiro Hybrid sirolimus-eluting stents in a broader population of all-comers are limited. The present study offers an angiographic and clinical comparison of the Orsiro Hybrid sirolimus-eluting stent and the Resolute Integrity zotarolimus-eluting stent in the treatment of patients with coronary artery disease. Methods/design : The ORIENT trial is a multicenter, randomized, open-label, parallel-arm study designed to demonstrate the non-inferiority of the Orsiro Hybrid sirolimus-eluting stent relative to the Resolute Integrity zotarolimus-eluting stent. A total of 375 patients with a spectrum of coronary artery disease will undergo prospective, random assignment to a Orsiro Hybrid sirolimus-eluting stent or Resolute Integrity zotarolimus-eluting stent (2:1 ratio), for a primary endpoint of in-stent late lumen loss at 9 months by quantitative coronary angiography. Secondary 12-month clinical endpoints are death, target lesion revascularization, target vessel revascularization, myocardial infarction, stent thrombosis and target lesion failure (a composite of cardiac death, target lesion revascularization and target vessel-related myocardial infarction). Discussion : The ORIENT trial is the first study to date comparing the Orsiro Hybrid sirolimus-eluting stent with the Resolute Integrity zotarolimus-eluting stent for efficacy and safety in a population of all-comers with coronary artery disease.This study is supported by a grant from Biotronik Korea.Peer Reviewe

    A Rare Case of Aortic Valve Myxoma: Easy to Confuse With Papillary Fibroelastoma

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    Myxoma of the aortic valve is an exceedingly uncommon condition. In this article, we report the case of a 72-year-old man with myxoma arising from the aortic valve. We extirpated the mass and repaired the aortic valve with the patient under cardiopulmonary bypass. The postoperative course was uneventful. Histological examination confirmed that the mass was a myxoma
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