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Clinical Features and Risk Factors of Post-COVID-19 Condition in Korea
Jang Myungwon,Choi Dong-Kwon,Choi Jonghyuk,Kwon Ho-Jang 대한예방의학회 2023 예방의학회지 Vol.56 No.5
Objectives: Numerous studies have explored the causes and spread of outbreaks, yet there is a lack of research on post-coronavirus disease 2019 condition (PCC) in Korea. The goal of this study was to identify the various types of PCC and associated factors in discharged patients and to provide directions for the ongoing health management of confirmed patients.Methods: A telephone survey was conducted among 680 coronavirus disease 2019 (COVID-19) patients diagnosed between July 7, 2021 and August 26, 2021, in Dangjin, Chungnam, Korea. A descriptive analysis of characteristics, univariate analysis, and regression were performed using data from basic epidemiological surveys conducted at the time of diagnosis and post-discharge questionnaires.Results: Of the 585 patients who responded, 159 (27.2%) developed PCC. Of the 211 patients with no initial symptoms, 27 (12.8%) developed PCC, versus 132 (35.3%) of the 374 patients with initial symptoms. Among the initial symptoms, fever or chills, cough or sputum, loss of smell, and sore throat were associated with PCC. Compared to patients with less than 10 days of hospitalization, those with a hospitalization period of 21 days to 30 days (odds ratio [OR], 2.3; 95% confidence interval [CI], 1.0 to 5.2) and 31 days or more (OR, 5.8; 95% CI, 1.9 to 18.1) had a higher risk of PCC.Conclusions: More than a quarter of COVID-19 patients, including those who had no initial symptoms, experienced PCC in Korea. People with the initial symptoms of fever, chills, and respiratory symptoms and those who had prolonged hospital stays had a high risk of PCC.
단동온실에서 강제환기가 열유동특성에 미치는 영향에 대한 수치해석 연구
윤종혁(Jonghyuk Yoon),송형운(Hyoungwoon Song),장은석(Eun-suk Jang) 한국열환경공학회 2020 한국열환경공학회 학술대회지 Vol.2020 No.춘계
With the advent of the 4th industrial revolution, smart farming technology is being introduced that can properly maintain the growing environment of crops remotely and automatically by grafting information and communication technology (ICT) to greenhouses. To maintain an appropriate growth environment for these crops, the effects of the greenhouse design parameters on these environments needs to be evaluated. In this study, the thermal and flow characteristics in the single-span greenhouse were examined with commercial computational fluid dynamics (CFD) code. To validate the numerical method applied herein, the numerical results of the temperature distribution at several monitoring points were compared with the experimental results. The low-average error rate (0.87 to 1.90 %) between them was measured and the numerical results of the temperature distribution exhibited good agreement with the experimental data. In addition, the effect of forced ventilation on thermal-flow characteristics was evaluated. These study findings will offer appropriate data for design guidelines for greenhouses.
연소공기비율에 따른 가축분뇨연료 소각로 내 연소특성에 대한 수치해석 연구
윤종혁 ( Jonghyuk Yoon ),송형운 ( Hyoungwoon Song ),장은석 ( Eun-suk Jang ) 한국폐기물자원순환학회 2021 한국폐기물자원순환학회지 Vol.38 No.4
With the depletion of fossil fuels, the use of new and renewable energy has attracted significant attention. Among various biomass fuels, wood pellets and chips are used as commercial fuels owing to their low water content compared to sewage sludge and food waste. Recently, the use of livestock manure as fuel has attracted significant owing to its ease of collection and transportation. However, the low economic feasibility of co-firing boiler, which is used to process livestock manure solid refuse fuel (SRF), has limited the further application of livestock manure. Therefore, the development of an efficient grate boiler for livestock-manure is highly needed. In this study, a three-dimensional computational fluid dynamics simulation was performed to evaluate the combustion performance of a livestock manure SRF grate furnace. To validate the numerical method, the numerical results of the temperature and species concentration at several monitoring points were compared to those of the experimental results. In addition, a parametric study was performed using various ratios of primary to assist air to understand the effects of air conditions on the overall combustion performance.
Mercury Exposure in Association With Decrease of Liver Function in Adults: A Longitudinal Study
Choi, Jonghyuk,Bae, Sanghyuk,Lim, Hyungryul,Lim, Ji-Ae,Lee, Yong-Han,Ha, Mina,Kwon, Ho-Jang The Korean Society for Preventive Medicine 2017 Journal of Preventive Medicine and Public Health Vol.50 No.6
Objectives: Although mercury (Hg) exposure is known to be neurotoxic in humans, its effects on liver function have been less often reported. The aim of this study was to investigate whether total Hg exposure in Korean adults was associated with elevated serum levels of the liver enzymes aspartate aminotransferase (AST), alanine transaminase (ALT), and gamma-glutamyltransferase (GGT). Methods: We repeatedly examined the levels of total Hg and liver enzymes in the blood of 508 adults during 2010-2011 and 2014-2015. Cross-sectional associations between levels of blood Hg and liver enzymes were analyzed using a generalized linear model, and nonlinear relationships were analyzed using a generalized additive mixed model. Generalized estimating equations were applied to examine longitudinal associations, considering the correlations of individuals measured repeatedly. Results: GGT increased by 11.0% (95% confidence interval [CI], 4.5 to 18.0%) in women and 8.1% (95% CI, -0.5 to 17.4%) in men per doubling of Hg levels, but AST and ALT were not significantly associated with Hg in either men or women. In women who drank more than 2 or 3 times per week, AST, ALT, and GGT levels increased by 10.6% (95% CI, 4.2 to 17.5%), 7.7% (95% CI, 1.1 to 14.7%), and 37.5% (95% CI,15.2 to 64.3%) per doubling of Hg levels, respectively, showing an interaction between blood Hg levels and drinking. Conclusions: Hg exposure was associated with an elevated serum concentration of GGT. Especially in women who were frequent drinkers, AST, ALT, and GGT showed a significant increase, with a significant synergistic effect of Hg and alcohol consumption.
Lee, Sanghwa,Jang, Sukwoo,Kim, Kyungtae,Jeon, Jonghyuk,Kim, Sung-Soo,Sohn, Byeong-Hyeok unknown 2016 Chemical communications Vol. No.
<P>We report controlled branching and eventual crosslinking in supracolloidal chains by introducing well-defined trifunctional patchy micelles. Uniform micelles having three patches were induced from core-crosslinked micelles of diblock copolymers. Three patches in the micelles served as functional groups for crosslinking as well as branching in supracolloidal polymerization.</P>