• Smart Media Journal
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• v.11 no.7
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• pp.9-18
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• 2022

With the outbreak of COVID-19, the world is in unexpected chaos. In particular, the Korean economy, which has a large number of self-employed people, is experiencing enormous damage from COVID-19. The purpose of this study is to analyze the causal impact of start-ups and closures by industry due to the COVID-19 outbreak. For the causal impact analysis, we collected and analyzed 8,312,224 cases of start-up and closure of 190 businesses that occurred on the local administrative license data public site for 11 years from 2010 to 2020. As a result of the analysis of the causal impact of COVID-19, there were 29 industries in which start-ups increased(increase rate 313.14% ~ 6.39%), 23 industries in which start-ups decreased(decrease rate 70.62% ~ 11.27%), 21 industries in which closures increased(increase rate 157.55% ~ 13.57%), and 18 industries in which business closures decreased(reduction rate 49.45% ~ 12.91%). The industries in which start-ups increased and closures decreased due to the COVID-19 outbreak were disinfection, food transportation, and general sales of health functional food. The industries in where start-ups decreased and closures increased due to the COVID-19 outbreak were youth game providing industry, danran pub business, and general game providing industry. It is expected that the results of this study will help practitioners who manage various infectious diseases to understand the causal impact of infectious disease outbreaks and to prepare countermeasures.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2023.04a
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• pp.37-37
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• 2023

천마(天麻, Gastrodia elata Blume)는 난초과(蘭草科, Orchidaceae)에 속하는 식물로 잎과 뿌리가 없어 탄소동화능력이 없으며, 뽕나무버섯균과 공생하는 기생식물이다. 천마는 노지재배 시 혹한, 폭우 등 기상환경에 따른 연차간 수량성 차가 673~1,175kg/10a로 크고, 연작에 따른 수량성이 연작 1회 시 29%, 연작 2회 시 68%가 감소하는 경향을 보이고 있다. 최근 기후변화 대응으로 비가림시설재배가 이뤄지고 있으나, 비가림 시설재배 또한 연작장해가 발생하고 있다. 따라서, 본 연구는 비가림시설을 활용한 천마 재배의 연작장해 경감을 위해 태양열(6~10월, 비닐피복) 및 토양훈증(메탐소듐, 30 L/1,000 m²)으로 토양소독 처리를 하였고, 윤작(수단그라스)을 대조구로 설정하여 토양 화학성, 미생물상 및 수량성을 분석하였다. 토양소독 전·후 토양내 화학성을 분석한 결과, 비가림시설재배 시 토양 화학성의 변화는 거의 없었다. 토양소독 후 metagenome 분석 결과, JCR21(윤작), JCS21(태양열), JCF21(토양훈증)의 시료로부터 확보한 총 read는 598,425개였으며, 이 중에서 Eukaryota로 분류되지 않은 read는 2,397개(0.4%), no hit, not assign된 read는 17,094개 (2.9%), Bacteria로 분류된 read는 281,391개(47.0%), Eukaryota로 분류된 read는 총 297,543개(49.7%)였다. JCR21은 전체 read의 35.0%, JCS21은 34.0%, JCF21은 31.0%를 차지했고, Eukaryota는 JCR21 대비 JCS21, JCF21에서 각각 9.9%, 18.9% 낮았다. 그리고, Bacteria는 JCR21 대비 JCF21은 5.4% 감소하였으나, JCS21은 1.4% 증가하였다. 이 중 Eukaryota에서 종(species)명까지 정확하게 밝혀진 것은 27종이었고 속(genus) 으로는 18속이었다. JCF21은 전체 read의 30.2%, JCS21은 33.8%, JCR21은 36.0%를 차지했고, JCF21 포장은 토양훈증으로 JCS21에 비해 3.6%, JCR21에 비해 5.8%까지 균수가 감소함을 알 수 있었다. 대체적으로 발견된 균은 고르게 분포하고 있었으나 초작지, 연작 1회지, 연작 2회지에서는 많이 발견되지 않았던 Mucoromycota (41,490 read, 13.9%), Agaricales (10,586 read, 3.6%)가 높은 비율로 분포를 하고 있었다. 토양소독 처리에 따른 10a 당 수량을 살펴본 결과, 윤작 1,309 kg, 태양열소독 1,609 kg, 토양훈증 1,733 kg으로 나타났고, 수량지수가 윤작 처리구 대비 태양열소독은 23%, 토양훈증은 32% 높았다. 성마율은 윤작 51%, 태양열소독 63%, 토양훈증 68%으로 나타났으며, 자마율은 윤작 49%, 태양열소독 37%, 토양훈증 32%으로 나타났다. 괴경썩음 정도는 윤작 30-49%, 태양열소독 10-19%, 토양훈증 5-9%로 나타났다. 따라서, 비가림시설을 활용한 천마 재배 시 토양훈증 소독 처리를 하면 연작이 가능할 것으로 판단되었다.

• Korean Journal of Poultry Science
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• v.50 no.4
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• pp.267-272
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• 2023

This study was conducted to investigate the effect of integrated pest management (IPM) with 3point 5score microscopic monitoring method for laying farms infected with poultry red mites. A total of 8 laying farms infected with poultry red mites were divided into two treatments: 1) integrated pest management with 3point 5score microscopic monitoring method and 2) normal pest management with 3point 5score microscopic monitoring method. The results revealed that there is no significant difference between the groups with respect to the score of poultry red mites not only regardless of disinfection for the laying farms but also from week 4 to week 20 (P>0.05). However, the farm with IPM had a lower (P<0.05) score than those with the normal pest management method on week 24. Based on the result of the present study, controlling the presence of poultry red mites using IPM, along with consistent monitoring and supplementation using the 3point 5score microscopic monitoring method, is deemed effective in reducing the ultimately targeted infection rate of poultry red mites.

• Journal of the Korean Society of Radiology
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• v.84 no.4
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• pp.891-899
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• 2023

Purpose To survey perceptions of certified physicians on the protocol of chest CT in patients with coronavirus (COVID-19) using a negative pressure isolation stretcher (NPIS). Materials and Methods This study collected questionnaire responses from a total of 27 certified physicians who had previously performed chest CT with NPIS in COVID-19 isolation hospitals. Results The nine surveyed hospitals performed an average of 116 chest CT examinations with NPIS each year. Of these, an average of 24 cases (21%) were contrast chest CT. Of the 9 pulmonologists we surveyed, 5 (56%) agreed that patients who showed abnormalities in serum D-dimer required contrast chest CT. All 9 surveyed radiologists agreed that the image quality of the chest CT with NPIS was sufficient for CT image interpretation regarding pneumonia or pulmonary embolism. Furthermore, in our 9 surveyed infectionologists, 5 (56%) agreed that a risk of secondary infection in the CT room after temporary opening of NPIS could be prevented through a process of disinfection. Conclusion Experienced physicians considered that the effects of NIPS on chest CT image quality was minimal in patients with COVID-19, and the risk of CT room contamination was easily controlled.

• Journal of Radiation Industry
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• v.17 no.2
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• pp.151-160
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• 2023

The International Atomic Energy Agency (IAEA) proposes 11 industries that handle Naturally Occurring Radioactive Material (NORM) that are considered to need management. A water treatment facility is one of the above industries that takes in groundwater and produces drinking water through a water treatment process. Groundwater can accumulate natural radionuclides such as uranium and thorium in raw water by contacting rocks or soil containing natural radionuclides. Therefore, there is a possibility that workers in water treatment facilities will be exposed due to the accumulation of natural radionuclides in the water treatment process. The goal of this study is to evaluate the external radiation dose according to the working type of workers in water treatment facilities. In order to achieve the above goal, the study was conducted by dividing it into 1) analysis of the exposure environment, 2) measurement of the external radiation dose rate 3) evaluation of the external radiation dose. In the stage of analyzing the exposure environment, major processes that are expected to occur significantly were derived. In the measurement stage of the external radiation dose rate, a map of the external radiation dose rate was prepared by measuring the spatial radiation dose rate in major processes. Through this, detailed measurement points were selected considering the movement of workers. In the external radiation dose evaluation stage, the external radiation dose was evaluated based on the previously derived external radiation dose rate and working time. As a result of measuring the external radiation dose rate at the detailed points of water treatment facilities A to C, it was 1.90×10^-1 to 3.75×10⁰ μSv h^-1, and the external radiation dose was analyzed as 3.27×10^-3 to 9.85×10^-2 mSv y^-1. The maximum external radiation dose appeared during the disinfection and cleaning of activated carbon at facility B, and it is judged that natural radionuclides were concentrated in activated carbon. It was found that the external radiation dose of workers in the water treatment facility was less than 1mSv y^-1, which is about 10% of the dose limit for the public. As a result of this study, it was found that the radiological effect of external radiation dose of domestic water treatment facility workers was insignificant. The results are expected to contribute as background data to present optimized safety management measures for domestic NORM industries in the future.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.8
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• pp.542-548
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• 2014

Effects of bromide ($Br^-$) and iodide ($I^-$) concentrations, chlorine ($Cl_2$) doses, pH, temperature, ammonia nitrogen concentrations, reaction times and water characteristics on formation of iodinated trihalomethanes (I-THMs) during oxidation of iodide containing water with chlorine were investigated in this study. Results showed that the yields of I-THMs increased with the high bromide and iodide level during chlorination. The elevated pH significantly increased the yields of I-THMs during chlorination. The formation of I-THMs was higher at $20^{\circ}C$ than $4^{\circ}C$, $10^{\circ}C$ and $30^{\circ}C$. In chloramination study, addition of ammonium chloride ($NH_4Cl$) markedly increased the formation of I-THMs. Among the water samples collected from seven water sources including wastewater treatment plant (WWTP) effluent water (EfOM water), prepared humic containing water (HA water) and algal organic matter (AOM) containing water (AOM water), EfOM water generated the highest yields of I-THMs ($12.31{\mu}g/mg$ DOC), followed by HA water ($4.96{\mu}g/mg$ DOC), while AOM water produced the lowest yields of I-THMs ($0.99{\mu}g/mg$ DOC). $SUVA_{254}$ values of EfOM water, HA water and AOM water were $1.38L/mg{\cdot}m$, $4.96L/mg{\cdot}m$ and $0.97L/mg{\cdot}m$, respectively. The I-THMs yields had a low correlation with $SUVA_{254}$ values ($r^2$ = 0.002).

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.4
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• pp.287-297
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• 2014

Purpose: The purpose of this study is to examine the impacts of infection control education on dental hygienists' perceptions for hepatitis B and their behaviors. Materials and methods: Study participants were chosen by random selection among dental hygienists working in Seoul, Korea. A total of 150 questionnaires were sent out for the survey from April 2013 to May 2013, of which 140-excluding incomplete responses-were used for the study. Chi-square tests and t-tests were used (SPSS 19.0), and post-hoc analysis was performed as well. The maximum significance level was 0.05. Results: Average 1.53 times infection control education was taken, but dental hygienists' perceptions for hepatitis B and their behaviors did not show statistical differences whether the education was done or not. Practices to prevent infection showed differences depending on categories, especially disinfection and sterilization were well performed by educated group. The most common reasons for not taking the education and noncompliance with infection prevention guidelines are lack of time and opportunity due to busy schedule. Conclusion: 1. The more highly educated, the greater number of patients per day, and the greater size of hospitals, the better infection control education was conducted. 2. Although hepatitis B is one of the most common chronic liver diseases in Korea, no significant correlation between perceptions of hepatitis B and infection control education was found. 3. Dental hygienists who received infection control education performed more efficient practices for protection against infections than those who did not.

• Korean Journal of Poultry Science
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• v.40 no.1
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• pp.11-16
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• 2013

Salmonella is closely related with human health of modern society which has concern increased in livestock goods consumption as well as give economic damage throughout the chicken industry such as farm, hatchery, slaughter house and processing plant. From 2007 to 2011, this study investigated Salmonella prevalence from 200 old hen delivery trucks which deliver old egg-laying hens and broiler breeders in Korea. The prevalence of Salmonella species was 38.0% in old hen delivery truck. Serogroup C1 was the most frequently detected serogroup of Salmonella, followed by the serogroups D1, C2 and B. A total of 25 serotypes were identified and Salmonella infantis was the most frequently isolated serotype. In addition, we applied disinfectant to old hen delivery truck for the reduction of Salmonella contamination. The disinfectant consists of formaldehyde, glutaladehyde and quaternary ammonium compound was applied to the trucks. Salmonella isolation rate was significantly decreased after disinfection from 38.0% to 7.5%. Disinfectant could not effectively reduce Salmonella contamination at a dilution of 1:200 which is recommended by manufacturer, but Salmonella isolation rate was significantly decreased at a dilution of 1:50. Since old hen delivery truck could be a potential vector to carry Salmonella into farms and abattoirs, chicken delivery truck should be disinfected thoroughly and sufficiently to control contamination of farms and abattoirs.

• Journal of dental hygiene science
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• v.15 no.5
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• pp.659-665
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• 2015

A wide variety of methods have been used to control Dental Unit Waterline (DUWL) contamination. Among the methods, flushing is mainly used because it is simple and easy to use. Generally, flushing of DUWL for 20 or 30 sec before using high speed handpieces or scalers is recommended. However, the appropriateness of flushing time was not investigated thoroughly. The purpose of this study was to check the effective time of flushing for decreasing bacterial contamination. Seven dental unit chairs were randomly selected in student clinical simulation laboratory for this experiment. DUWLs were continuously flushed and water samples were collected at an interval of 30 seconds for 15 minutes. From five dental unit chairs, water samples were collected every 10 seconds for 1 minute. Bacterial levels in water samples were examined by the culture method on R2A plates. After 10 second flushing of DUWLs, the number of bacteria significantly reduced and decreased continuously up to 40 seconds. However, even after the water was flushed for 15 minutes, the bacterial contamination level was not reduced below recommended bacteria level, 200 CFU/ml. In addition to flushing, the periodic chemical disinfection is required to control the DUWL water to the recommended level.

• Journal of Environmental Science International
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• v.3 no.3
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• pp.253-261
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• 1994

Chloroform present in the swimming water disinfected with sodium hypochlorite is released to the air of swimming pools. The air chloroform concentrations were measured in two swimming pools A and B which applied both sodium hypochlorite a:d ozone. Thew mean concentrations are 28.0 $\mu\textrm{g}$/m3 and 33.6 $\mu\textrm{g}$/m3in the swimming pools A and B, respectively. On the other hand, the mean water chloroform concentrations in the swimming pools A and B were 23.9 $\mu\textrm{g}$/l and 19.5 $\mu\textrm{g}$/l, respectively. The air chloroform concentrations were lower in the swimming Bools A and B than those reported by previous studies abroad employed the swimming pools which applied sodium hypochlorite only for water disinfection. The water chloroform concentrations were also lower in this study than in the previous studies. The relationship between the air and water chloroform concentrations measured in this study was significant with p=0.002 and Rz=0.42. At similar time to the indoor air sampling, outdoor air samples were collected at two sites near each of the swimming Pools A and B. The mean outdoor air chloroform concentrations near the swiminE Pools A and B were 0.41 $\mu\textrm{g}$/m3 and 0.16 $\mu\textrm{g}$/m3, respectively. The outdoor air chloroform concentrations measured in this study were equal to or lower than those reported by previous studies abroad. 'rho chloroform dose inhaled for a typical one-hour swim was estimated to be 25.9 $\mu\textrm{g}$ per person, corresponding to a specific 0.37 $\mu\textrm{g}$/kg body weight for a reference 70 Kg male adult, while the inhalation dose of chloroform from the outdoor air was estimated to be 5.6 $\mu\textrm{g}$ per person per day, corresponding to a specific 0.08 $\mu\textrm{g}$/Kg/day for the same reference male adult.