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( Jaehoon Chung ),( Jung-kyu Han ),( Han-mo Yang ),( Kyung-woo Park ),( Hyun-jae Kang ),( Bon-kwon Koo ),( Myung Ho Jeong ),( Hyo-soo Kim ) 대한내과학회 2021 The Korean Journal of Internal Medicine Vol.36 No.0
Background/Aims: Long-term benefit of vasodilating β-blockers is unknown. This study aimed to investigate the long-term benefit of vasodilating β-blockers over conventional β-blockers in patients with acute myocardial infarction (AMI). Methods: Using nationwide prospective multicenter Korean Acute Myocardial Infarction Registry data, we analyzed 3-year clinical outcomes of 7,269 patients with AMI who received percutaneous coronary intervention (PCI) and β-blocker therapy. Patients were classified according to treatment strategy (vasodilating β-blockers vs. conventional β-blockers). The primary endpoint was a composite of cardiac death, myocardial infarction (MI), and hospitalization for heart failure (HF) at 3 years. Secondary outcomes were each component of the primary outcome. Propensity score matching was performed to adjust for differences of baseline characteristics. Results: In 3,079 pairs (6,158 patients) of propensity score-matched patients, the primary outcome occurred significantly less in the vasodilating β-blockers group compared with the conventional β-blockers group (7.6% vs. 9.8%, p = 0.003). Among the secondary outcomes, cardiac death occurred significantly less in the vasodilating β-blockers group than in the conventional group (3.5% vs. 4.8%, p = 0.015). The incidence rates of MI (2.4% vs. 3.0%, p = 0.160) or hospitalization for HF (2.6% vs. 3.2%, p = 0.192) were not significantly different between the two groups. Conclusions: Vasodilating β-blocker therapy was associated with better clinical outcomes compared with conventional β-blocker therapy in AMI patients undergoing PCI during 3 years follow-up. Vasodilating β-blockers could be recommended preferentially for these patients.
Chung, Jaehoon,Won, Da Hye,Koh, Jaekang,Kim, Eun-Hee,Woo, Seong Ihl The Royal Society of Chemistry 2016 Physical Chemistry Chemical Physics Vol.18 No.8
<P>To achieve high performance of electrochemical CO2 reduction, a series of Cu pillar electrodes (Cu-2.5 h, Cu-5 h) were fabricated by using an electrodeposition method, and then their catalytic activities and reaction mechanisms were investigated. The series of Cu pillar electrodes exhibited improved electrocatalytic activities toward CO2 reduction to formic acid (HCOOH) as Cu pillars on electrodes developed. The Cu-5 h electrode performed well with a 28% Faradaic efficiency for formic acid at -0.5 V (vs. RHE). X-ray diffraction (XRD) analysis indicated that the enhanced catalytic activities were primarily attributable to the increased (111) facet, which is energetically favourable for the production of HCOOH. Also, ultraviolet photoelectron spectroscopy (UPS) and in situ electrochemical impedance spectroscopy (EIS) results suggested that the series of Cu pillar structure electrodes improved the electron transfer to adsorbed CO2 due to the decreased work function of the Cu pillar structure.</P>
Design of an ultrawide-band TEM horn antenna with a microstrip-type balun
Chung, Kyungho,Pyun, S.,Choi, Jaehoon IEEE 2005 IEEE transactions on antennas and propagation Vol.53 No.10
An exponentially tapered ultrawide-band transverse electromagnetic (TEM) horn antenna having a microstrip-type balun is designed. The balun is used to improve the impedance characteristic of a TEM horn antenna. The measured bandwidth for VSWR less than 2.0 ranges from 67.94 to 1573.9 MHz. The bandwidth of the proposed TEM horn is three times wider than that of the linearly tapered TEM horn. The designed antenna can be used not only for electromagnetic compatibility measurement but also for broad-band communication system.
Chung, Kyungho,Choi, Jaehoon Wiley Subscription Services, Inc., A Wiley Company 2008 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Vol.50 No.1
<P>A compact microstrip band-selective filter for ultra-wideband (3.1–10.6 GHz) radio system is proposed. The filter combines an optimum pseudo-bandpass filter and a coupled resonator bandstop filter on both sides of the meandered 50-Ω microstrip line. Three coupled resonators are modified to have S-shape to miniaturize the filter. The measured results show that the filter has wide passband of 146.7% (2.1–10.15 GHz) with low insertion loss and the stop-band of 7.42% (5.29–5.85 GHz) for 3-dB bandwidth. The measured group delay variation is less than 0.7 ns within the passband except the stop band. Finally, the filter is combined with band-notched antennas and then received power levels of the antennas with and without the filter are also examined at the notch frequency. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 98–101, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23019</P>
Miniaturization of an UHF RFID reader antenna using an artificial magneto-dielectric
Chung, Haeil,Lee, Youngki,Choi, Jaehoon Wiley Subscription Services, Inc., A Wiley Company 2010 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Vol.52 No.9
<P>In this article, a miniaturization method for a ultrahigh frequency radio frequency identification reader antenna using an artificial magneto-dielectric is proposed. The miniaturization was achieved using an artificial magneto-dielectric, realized using a split ring resonator (SRR). The 10 dB return loss bandwidth of the designed antenna ranges from 908.5 to 914 MHz. The measured peak gain is −3.75 dBi and the axial ratio is below 3 dB over the frequency band of interest. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1926–1930, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25423</P>
Reconfigurable microstrip-patch antenna with frequency and polarization-diversity functions
Chung, Kyungho,Nam, Yongsik,Yun, Taeyeoul,Choi, Jaehoon Wiley Subscription Services, Inc., A Wiley Company 2005 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Vol.47 No.6
<P>The design of a novel reconfigurable microstrip-patch antenna with frequency- and polarization-diversity functions is presented. A U-slot inserted into the square patch and a PIN diode are utilized to realize frequency-diversity operation. Polarization diversity between linear polarization (LP) and right-hand circular polarization (RHCP) is also provided by switching the two PIN diodes on the truncating corners of a square patch on and off. The designed antenna is implemented and the antenna characteristics are measured. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 605–607, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21242</P>