290 research outputs found

    Deep Seawater flow Characteristics Around the Manganese Nodule Collecting Device

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    AbstractFlow field characteristics with outflow discharge from a collecting device in deep seawater while gathering manganese nodules have been analyzed by CFD. Numerical model is used for the analysis with CFD program of FLUENT. It is assumed that the collecting device is 4.5×5.4×6.7m with outflow speed = 1.75 m/s and the current speed = 0.1m/s.Overall seawater flow field characteristics are largely influenced by the outflow discharge from the collecting device and manganese nodule particle behavior. The outflow discharge effect reaches to about few times of the collecting device in back. As simulation results, flow velocity and streamline distributions are compared including turbulence kinetic energyvariation. This study will be useful for optimal design for manganese nodule collecting device system in deep sea

    A highly active and durable lanthanum strontium cobalt ferrite cathode for Intermediate-Temperature solid Oxide fuel cel

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    Solid oxide fuel cells (SOFCs) are promising techniques for high energy efficiency, fuel flexibility, and low pollutant emissions. For commercialization of SOFCs, it is required to decrease the operating temperature. At this intermediate temperature region, the cathodic polarization resistance significant due to the thermally activated oxygen reduction reaction (ORR). To compensate this, highly active cathode materials have been considered and lanthanum strontium cobalt ferrite (LSCF6428, La0.6Sr0.4Co0.2Fe0.8O3-δ) has been attracted as a cathode material for SOFCs because of its high mixed electronic and ionic conducting (MIEC) nature. However, one of the major concerns of LSCF6428 is the degradation during the long-term operation. Currently, Sr segregation has been reported as one of the major reasons for the LSCF degradation. In this study, we investigated LSCF2882 (La0.2Sr0.8Co0.8Fe0.2O3-δ) and compared with LSCF6428 as a SOFC cathode. X-ray diffraction (XRD) and Rietveld refinement were applied to analyze phase structures. By electrical conductivity relaxation (ECR) technique, Oxygen surface exchange coefficients (kchem) and chemical diffusion coefficients (Dchem) of LSCF2882 were evaluated and we observed enhancements compare to LSCF6428. For interpretation of enhanced oxygen transport kinetics, we tried to visualize the interstitial oxygen conduction pathways and the bond valence sum (BVS) mapping method was utilized by Valence program. BVS mapping results show clearly demonstrating the 3D network of the interstitial pathways at 600oC in LSCF2882. Electrochemical performances were investigated by EIS (Electrochemical Impedance Spectroscopy) and single cell performance was also evaluated. In addition, long-term stability test was performed for over 500 hours. LSCF2882 showed better performances and it exhibited no degradation during the stability test. Please click Additional Files below to see the full abstract

    Comparison of infarct-related artery vs multivessel revascularization in ST-segment elevation myocardial infarction with multivessel disease: Analysis from Korea Acute Myocardial Infarction Registry

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    Background: Many ST-segment elevation myocardial infarction (STEMI) patients have multivessel disease. There is still controversy in treatment strategy in STEMI patients with multivessel disease. We compared clinical outcomes of multivessel revascularization with infarct- related artery (IRA) revascularization in STEMI patients. Methods: The 1,644 STEMI patients with multivessel disease (1,106 in IRA group, 538 in multivessel group) who were received primary percutaneous coronary intervention (PCI) were analyzed from a nationwide Korea Acute Myocardial Infarction Registry. Primary endpoint was 12-month major adverse cardiac events (MACE, defined as death, myocardial infarction, and repeated revascularization). Secondary endpoints were 1-month MACE and each component, stent thrombosis during 12 month follow-up, and each components of the 12-month MACE. Results: There were more patients with unfavorable baseline conditions in IRA group. 12-month MACE occurred in 165 (14.9%) patients in IRA group, 81 (15.1%) patients in multivessel group (p = 0.953). There were no statistical significance in the rate of 1-month MACE, each components of 1-month MACE, and stent thrombosis during 12 month follow-up. Each components of 12-month MACE were occurred similarly in both groups except for target lesion revascularization (2.4% in IRA group vs 5.9% in multivessel group, p < 0.0001). After adjusting for confounding factors, multivessel revascularization was not associated with reduced 12-month MACE (OR 1.096, 95% CI 0.676&#8211;1.775, p = 0.711). Conclusions: There were no significant differences in clinical outcomes between both groups except for high risk of target lesion revascularization in multivessel revascularization group

    Molecular Identification of Taenia Tapeworms by Cox1 Gene in Koh Kong, Cambodia

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    We collected fecal samples from 21 individuals infected with Taenia tapeworms in Koh Kong Province, Cambodia, and performed nucleotide sequencing of the cox1 gene and multiplex PCR on the eggs for DNA differential diagnosis of human Taenia tapeworms. Genomic DNA was extracted from the eggs of a minimum number of 10 isolated from fecal samples. Using oligonucleotide primers Ta7126F, Ts7313F, Tso7466F, and Rev7915, the multiplex PCR assay proved useful for differentially diagnosing Taenia solium, Taenia saginata, and Taenia asiatica based on 706, 629, and 474 bp bands, respectively. All of the Taenia specimens from Kho Kong, Cambodia, were identified as either T. saginata (n=19) or T. solium (n=2) by cox1 sequencing and multiplex PCR

    Improved hematopoietic differentiation of human pluripotent stem cells via estrogen receptor signaling pathway

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    Additional file 2: Table S1. Temporal changes (%) of ER-Îą and hematopoietic phenotypes during hiPSC-derived hematopoietic differentiation
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