• Journal of Cardiovascular Imaging
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• v.26 no.4
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• pp.217-225
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• 2018

BACKGROUND: In patients with acute heart failure (AHF), diastolic dysfunction, especially pseudonormal (PN) or restrictive filling pattern (RFP) of left ventricle (LV), is considered to be implicated in a poor prognosis. However, prognostic significance of diastolic dysfunction in patients with ischemic heart disease (IHD) has been rarely investigated in Korea. METHODS: We enrolled 138 patients with IHD presenting as AHF and sinus rhythm during echocardiographic study. Diastolic dysfunction of LV was graded as ${\geq}2$ (group 1) or 1 (group 2) according to usual algorithm using E/A ratio and deceleration time of mitral inflow, E'/A' ratio of tissue Doppler echocardiography and left atrial size. RESULTS: Patients in group 1 showed higher 2-year mortality rate ($36.2%{\pm}6.7%$) than those in group 2 ($13.6%{\pm}4.5%$; p = 0.008). Two-year mortality rate of patient with LV ejection fraction (LVEF) < 40% ($26.8%{\pm}6.0%$) was not different from those with LVEF 40%-49% ($28.0%{\pm}8.0%$) or ${\geq}50%$ ($13.7%{\pm}7.4%$; p = 0.442). On univariate analysis, PN or RFP of LV, higher stage of chronic kidney disease (CKD) and higher New York Heart Association (NYHA) functional class were poor prognostic factors, but LVEF or older age ${\geq}75$ years did not predict 2-year mortality. On multivariate analysis, PN or RFP of LV (hazard ratio [HR], 2.52; 95% confidence interval [CI], 1.09-5.84; p = 0.031), higher stage of CKD (HR, 1.57; 95% CI, 1.14-2.17; p = 0.006) and higher NYHA functional class (HR, 1.81; 95% CI, 1.11-2.94; p = 0.017) were still significant prognostic factors for 2-year mortality. CONCLUSIONS: PN or RFP of LV was a more useful prognostic factor for long-term mortality than LVEF in patients with IHD presenting as AHF.

• Nutrition Research and Practice
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• v.13 no.5
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• pp.393-398
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• 2019

BACKGROUND/OBJECTIVES: The association between tea consumption and risk of coronary heart disease (CHD) remains controversial. This study aimed to determine whether tea consumption has an effect on CHD risk in Chinese adults. SUBJECTS/METHODS: In this hospital-based case-control study, 267 cases of CHD and 235 non-CHD controls were enrolled. Blood samples from all cases were examined. Cardiac function indices (left ventricular ejection fraction, left ventricular end-diastolic dimension, lactate dehydrogenase, and creatine kinase of the muscle or brain type), blood lipid index (high-density lipoprotein cholesterol), and blood coagulation function indices (fibrinogen and activated partial thromboplastin time) were recorded. Tea consumption of study participants was assessed by a specifically designed questionnaire. The baseline characteristics of the study populations were recorded, and CHD-related biomarkers were detected. Differences in baseline characteristics of the study participants were examined using t-tests for continuous variables and chi-squared tests for categorical variables. Unconditional logistic regression was used to measure the association between tea and CHD. RESULTS: There were significant differences in cardiac function indices, blood lipid index, and blood coagulation indices between CHD cases and controls (P < 0.05). We found tea consumption reduced CHD risk in female participants (adjusted odds ratio (OR) = 0.484, 95% CI: 0.242-0.968, P = 0.0403). Regarding the type of tea consumed, the risk of CHD was reduced in women who drank partially fermented tea (adjusted OR = 0.210, 95% CI: 0.084-0.522, P = 0.0008). Analytic results for the amount of tea consumed per unit time showed CHD risk was reduced in women who consumed 1-2 cups of tea per day (adjusted OR = 0.291, 95% CI: 0.131-0.643, P = 0.0023). A tea-drinking frequency of > 6 days/week was beneficial for CHD prevention (adjusted OR = 0.183, 95% CI: 0.049-0.679, P = 0.0112). When analyzed according to the duration of tea consumption, the risk of CHD was reduced in participants who had been drinking tea for 10-20 years (adjusted OR = 0.360, 95% CI: 0.137-0.946, P = 0.0382). CONCLUSIONS: Tea consumption is associated with a reduced risk of CHD in female but not male populations in Guangzhou.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.7
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• pp.939-944
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• 2018

Clean fire extinguishing agents refer to chemical that can replace Halon 1211 and Halon 1310 according to the Montreal Protocol fermented to protect the Earth's ozone layer. In Korea and abroad, system standardization and performance evaluation of clean fire extinguishing agents are being carried out. This paper proposes an optimal nozzle shape by modeling and numerical analysis of various nozzle shapes based on general clean fire extinguishing system. The ejection speed of the nozzle can be improved by studying three - dimensional modeling of the nozzle for two shapes, Type A and B. Flow analysis was performed on the two types of nozzles and the gas velocity and pressure distribution were measured with different nozzle diameters. It was confirmed that the jetting speed was changed at the nozzle outlet according to the number and diameter of the nozzle holes. The flow rate increased with increasing the pressure regardless of the nozzle hole diameter. Based on the results obtained from the experiment, the K-factor value was deduced. Finally, a nozzle with a 12-hole structure with a 5-mm nozzle hole was proposed.

• Journal of Veterinary Clinics
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• v.36 no.1
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• pp.46-52
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• 2019

Pimobendan has inotropic and vasodilating effects on cardiovascular system, and pentoxifylline is known to decrease blood viscosity and improve blood flow to the heart. This study investigated the pharmacokinetics and pharmacodynamics following oral administration of pimobendan-pentoxifylline powder mixture in dogs. Eight healthy dogs were included and were divided into control (n = 4) and experimental (n = 4) groups. Vehicle powder and pimobendan-pentoxifylline powder mixture (pimobendane 0.25 mg/kg, pentoxifylline 15 mg/kg) were administrated orally to control and experimental groups, respectively. Plasma samples and measurement of echocardiographic indices were obtained for 24 hours following administration. Pimobendan and pentoxifylline concentrations were investigated using liquid chromatography-mass spectrometer (LC-MS) assay. The elimination half-life ($T_{1/2}$) were $2.65{\pm}1.42hours$ for pimobendan and $0.29{\pm}0.23hours$ for pentoxifylline. The time to reach maximum concentration ($T_{max}$) were $1.08{\pm}0.72hours$ for pimobendan and $0.29{\pm}0.14hours$ for pentoxifylline. The maximum blood concentration ($C_{max}$) were $2.83{\pm}1.50ng/mL$ for pimobendan and $1184.33{\pm}932.37ng/mL$ for pentoxifylline. Among echocardiographic indices, fractional shortening (FS), left ventricular internal diameter at end systole (LVIDs), and pre-ejection period (PEP) showed significant changes at 1-4 hours after the administration of pimobendan-pentoxifylline powder mixture. No adverse effects were observed during the investigation. This study demonstrates that pimobendan-pentoxifylline powder mixture can be used to control cardiovascular diseases in dogs.

• Korean Circulation Journal
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• v.48 no.11
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• pp.1002-1011
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• 2018

Background and Objectives: The prognostic impact of left axis deviation (LAD) on clinical outcomes in acute heart failure syndrome (AHFS) with left bundle branch block (LBBB) is unknown. The aim of this study was to determine the prognostic significance of axis deviation in acute heart failure patients with LBBB. Methods: Between March 2011 and February 2014, 292 consecutive AHFS patients with LBBB were recruited from 10 tertiary university hospitals. They were divided into groups with no LAD (n=189) or with LAD (n=103) groups according to QRS axis <-30 degree. The primary outcome was all-cause mortality. Results: The median follow-up duration was 24 months. On multivariate analysis, the rate of all-cause death did not significantly differ between the normal axis and LAD groups (39.7% vs. 46.6%, adjusted hazard ratio, 1.01; 95% confidence interval, 0.66, 1.53; p=0.97). However, on the multiple linear regression analysis to evaluate the predictors of the left ventricular ejection fraction (LVEF), presence of LAD significantly predicted a worse LVEF (adjusted beta, -3.25; 95% confidence interval, -5.82, -0.67; p=0.01). Right ventricle (RV) dilatation was defined as at least 2 of 3 electrocardiographic criteria (late R in lead aVR, low voltages in limb leads, and R/S ratio <1 in lead V5) and was more frequent in the LAD group than in the normal axis group (p<0.001). Conclusions: Among the AHFS with LBBB patients, LAD did not predict mortality, but it could be used as a significant predictor of worse LVEF and RV dilatation (Trial registry at KorAHF registry, ClinicalTrial.gov, NCT01389843).

• Journal of the Korean Geosynthetics Society
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• v.18 no.3
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• pp.33-44
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• 2019

Clinker layer is a stratum structure distributed in volcanic area such as Jeju Island. The clinker layers were formed in between the repetitive action of eruption and solidification of lava flows. Since the clinker layer contains a large amount of voids accompanied by the lava gas ejection process, there is a possibility of inducing overall stability of the ground due to the low stiffness and strength of the clinker layer. Therefore, in this study, site investigation was carried out at both ends of the 00 bridge where the clinker layers exist. And, based on the ground survey results, the behavior of shallow foundations was analyzed numerically. In addition, the improved shallow foundation behavior in grouting substitution using the chemical injection method of the clinker layer was compared with the shallow foundation behavior in the ground, and the grouting substitution efficiency of each layer was analyzed. As a result, the bearing capacity, the replacement efficiency and elastic settlement were different according to the presence or absence of the sediment layer. This is because the sediment layer has a lower stiffness and density than the clinker layer.

• Journal of Veterinary Clinics
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• v.38 no.3
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• pp.163-168
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• 2021

A 6-year-old, spayed female, Maltese dog with tachypnea and dry cough was presented to Gyeongsang National University Veterinary Medical Teaching hospital. On physical examination, its respiration rate was 132 per minute. Decreased partial pressure of oxygen, partial pressure of carbon dioxide, and hyperlactatemia were found on arterial blood gas analysis. Its diastolic blood pressure was 80 mmHg. Auscultation revealed arrhythmia. Electrocardiogram revealed P pulmonale, P mitrale, and ventricular premature complexes. Thoracic radiographs revealed mild enlargement of both atrium and moderate enlargement of the left ventricular. There was also a moderate alveolar pattern in the right and caudal part of the left cranial lung lobe. Two-dimensional echocardiography showed enlargement of generalized four chambers without remarkable findings of valvular degeneration. M-mode echocardiography showed decreased left ventricular fractional shortening and enlarged left ventricular internal diameter at both end-systolic and end-diastolic. Color-flow Doppler imaging revealed eccentric turbulent flow starting below the left ventricular outflow tract and extending into the left atrium during systole. Spectral Doppler recordings revealed a high velocity flow through the mitral, tricuspid, aorta, and pulmonic regurgitation. Restrictive transmitral flow revealed high E-wave velocity, short E-wave deceleration time, and reduced A-wave velocity. There was also low ejection velocity thorough left ventricular out tract flow. Based on echocardiographic examination, dilated cardiomyopathy was the tentative diagnosis. The dog was medicated with inotropes, angiotensin converting enzyme inhibitor, and diuretics. At the 10-day following-up, the dog died suddenly. This report describes echocardiographic diagnosis and prognosis of dilated cardiomyopathy rarely reported in small breed dogs.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.4
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• pp.305-316
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• 2022

Hydrogen energy is emerging as an alternative to the depletion of fossil fuels and environmental problems, and the use of hydrogen vehicles is increasing in the automobile industry as well. However, since hydrogen has a wide flammability limit of 4 to 75%, there is a high concern about safety in case of a hydrogen car accident. In particular, in semi-enclosed spaces such as tunnels and underground parking lots, a fire or explosion accompanied by hydrogen leakage is highly likely to cause a major accident. Therefore, it is necessary to review hydrogen safety through analysis of flammability areas caused by hydrogen leakage. Therefore, in this study, the effect of the air velocity in the tunnel on the flammability area was investigated by analyzing the hydrogen concentration according to the hydrogen leakage conditions of hydrogen vehicles and the air velocity in the tunnel in a road tunnel with standard section. Hydrogen leakage conditions were set as one tank leaking and three tanks leaking through the TPRD at the same time and a condition in which a large crack occurred and leaked. And the air velocity in the tunnel were considered 0, 1, 2.5, and 4.0 m/s. As a result of the analysis of the flammability area, it is shown that when the air velocity of 1 m/s or more exists, it is reduced by up to 25% compared to the case of air velocity of 0 m/s. But there is little effect of reducing the flammability area according to the increase of the wind speed. In particular, when a large crack occurs and completely leaks in about 2.5 seconds, the flammability area slightly increases as the air velocity increases. It was found that in the case of downward ejection, hydrogen gas remains under the vehicle for a considerably long time.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.8
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• pp.551-557
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• 2022

LRU (Line Replacement Unit) modifications are often required for military aircraft due to aging. Recently, LRU modifications were proceeded for KA-O (Armed Airborne Controller) by replacing the ejection seat and adding avionic equipment, which made the aircraft's operational CG (Center of Gravity) on fuel consumption curve become out of the range of the specification requested. The off-ranged CG should be corrected by introducing an appropriate method. This study proposes a procedure for revising and verifying the empty weight CG altered due to LRU modification for small military aircraft (e.g., KA-O). In the proposed method, first, the change of empty weight CG of KA-O due to the LRU modifications is comprehensively examined. Then, several ballast masses are added to the engine mount strut to restore the empty weight CG on the fuel consumption curve to a safe operational range. The installations are verified via stress and fatigue analysis for various operating conditions. Considering that open information is not very available for the revision of empty weight CG, this study is valuable because it presents an established procedure for correcting and verifying empty weight CG during aircraft modification.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.2
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• pp.153-170
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• 2022

Waterjet has been comprehensively used in urban areas owing to a suitable technique for cutting concrete and rock, and low noise and vibration. Recently, the abrasive waterjet technique has been adopted and applied by the Korea Atomic Energy Research Institute to demolish concrete plugging without disturbing and damaging In-situ Demonstration of Engineered Barrier System in the disposal research tunnel. In this study, the use of abrasive waterjet in the tunnel was evaluated for practical applicability and the existing cutting model was compared with the experimental results. As a variable for waterjet cutting, multi-cutting, water flow rate, abrasive flow rate, and standoff distance were selected for the diversity of analysis. As regarding the practical application, the waterjet facilitated path selection for cutting the concrete plugging and prevented additional disturbances in the periphery. The pump's noise at idling was 64.9 dB which is satisfied with the noise regulatory standard, but it exceeded the standard at ejection to air and target concrete because the experiment was performed in the tunnel space. The experimental result showed that the error between the predicted and measured cutting volume was 12~13% for the first cut and 16% for second cut. The standoff distance had a significant influence on the cutting depth and width, and the error tended to decrease with decrement of standoff distance.