• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.4
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• pp.299-311
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• 2020

This paper analyzes the distribution of water vapor pressure and relative humidity in complex terrains by collecting weather observation data at 6 locations in the valley in Jungdae-ri, Ganjeon-myeon, Gurye-gun, Jeolla South Province and 14 locations in Akyang-myeon, Hadong-gun, Gyeongsang South Province, which form a single drainage basin in rural and mountainous regions. Previously estimated water vapor pressure used in the early warning system for agrometeorological hazard and actual water vapor pressure arrived at using the temperature and humidity that were measured at the highest density (1.5 m above ground) at every hour in the valley of Jungdae-ri between 19 December 2014 and 23 November 2015 and in the valley of Akyang between 15 August 2012 and 18 August 2013 were compared. The altitude-specific gradient of the observed water vapor pressure varied with different hours of the day and the difference in water vapor pressure between high and low altitudes increased in the night. The hourly variations in the water vapor pressure in the weather stations of the valley of Akyang with various topographic and ground conditions were caused by factors other than altitude. From the observed data of the study area, a coefficient that adj usts the variation in the water vapor pressure according to the specific difference in altitude and estimates it closer to the actual measured level was derived. Relative humidity was simulated as water vapor pressure estimated against the saturated water vapor pressure, thus, confirming that errors were further reduced using the derived coefficient than with the previous method that was used in the early warning system.

• Tuberculosis and Respiratory Diseases
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• v.84 no.2
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• pp.125-133
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• 2021

Background: The coronavirus disease (COVID-19) can manifest in a range of symptoms, including both asymptomatic systems which appear nearly non-existent to the patient, all the way to the development of acute respiratory distress syndrome (ARDS). Specifically, COVID-19-associated pneumonia develops into ARDS due to the rapid progression of hypoxia, and although arterial blood gas analysis can assist in halting this deterioration, the current environment provided by the COVID-19 pandemic, which has led to an overall lack of medical resources or equipment, has made it difficult to administer such tests in a widespread manner. As a result, this study was conducted in order to determine whether the levels of oxygen saturation (SpO₂) and the fraction of inhaled oxygen (FiO₂) (SF ratio) can also serve as predictors of ARDS and the patient's risk of mortality. Methods: This was a retrospective cohort study conducted from February 2020 to Mary 2020, with the study's subjects consisting of COVID-19 pneumonia patients who had reached a state of deterioration that required the use of oxygen therapy. Of the 100 COVID-19 pneumonia cases, we compared 59 pneumonia patients who required oxygen therapy, divided into ARDS and non-ARDS pneumonia patients who required oxygen, and then investigated the different factors which affected their mortality. Results: At the time of admission, the ratios of SpO₂, FiO₂, and SF for the ARDS group differed significantly from those of the non-ARDS pneumonia support group who required oxygen (p<0.001). With respect to the predicting of the occurrence of ARDS, the SF ratio on admission and the SF ratio at exacerbation had an area under the curve which measured to be around 85.7% and 88.8% (p<0.001). Multivariate Cox regression analysis identified that the SF ratio at exacerbation (hazard ratio [HR], 0.916; 95% confidence interval [CI], 0.846-0.991; p=0.029) and National Early Warning Score (NEWS) (HR, 1.277; 95% CI, 1.010-1.615; p=0.041) were significant predictors of mortality. Conclusion: The SF ratio on admission and the SF ratio at exacerbation were strong predictors of the occurrence of ARDS, and the SF ratio at exacerbation and NEWS held a significant effect on mortality.

• Journal of Chest Surgery
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• v.54 no.2
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• pp.106-116
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• 2021

Background: We evaluated the mid-term outcomes and angiographic patency of redo coronary artery bypass grafting (CABG). Methods: Of 2,851 patients who underwent isolated CABG at Seoul National University Hospital from 2000 to 2017, 88 underwent redo CABG. Patients' mean age at redo CABG was 66.0±8.0 years. The mean interval between the first-time and redo CABG was 113.0±62.4 months. The mean follow-up duration was 86 months. Early and mid-term clinical outcomes were evaluated. Angiographic patency rates were evaluated early (1-2 days), 1 year, and 5 years after surgery. Comparative analyses between on-pump and off-pump CABG were also performed. Results: The culprits for reoperation were previous grafts (65.6%), native coronary vessels (17.8%), and both (16.7%). Off-pump CABG was performed in 75 cases (85.2%), and the mean number of distal anastomoses was 1.8±0.8. The saphenous vein (39.7%) was used most frequently, followed by the right internal thoracic artery (28.4%), right gastroepiploic artery (21.3%), left internal thoracic artery (7.8%), and radial artery (2.8%). Operative mortality was 1.1%. The overall survival, cumulative incidence of cardiac death, and cumulative incidence of major adverse cardiac events were 71.3%,12.0%, and 23.3% at 5 years after surgery, respectively. The overall angiographic patency rates were 95.7%, 90.1%, and 92.2% on early, 1-year, and 5-year angiograms, respectively. The angiographic patency rates of saphenous vein grafts were 93.1%, 85.6%, and 91.3% on early, 1-year, and 5-year angiograms, respectively. No significant differences in clinical outcomes or angiographic patency rates were observed between the on-pump (n=13) versus off-pump (n=75) groups. Multivariable analysis revealed that age (hazard ratio [HR], 1.07; p=0.005) and chronic kidney disease (HR, 3.85; p=0.001) were risk factors for all-cause mortality. Conclusion: Redo CABG could mostly be performed using the off-pump technique and did not show increased operative mortality and morbidities.

• The Journal of Korean Society for School & Community Health Education
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• v.22 no.4
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• pp.49-60
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• 2021

Objectives: Laboratories have various latent physical, chemical, biological, and ergonomical factors according to the diversification and fusion of research and development activities. This study aims to investigate the chemical exposure concentrations of college laboratories and evaluate their health risks, and use them as basic data to promote the health of college students. Methods: The sampling and analysis of harmful chemicals in the air in laboratories were performed using Method 1500 of the U.S. National Institute for Occupational Safety and Health (NIOSH)의 Method 1500. The harmful chemicals in the laboratories were divided into carcinogenic and non-carcinogenic chemicals. Risk assessment was performed using the cancer risk (CR) for carcinogenic chemicals and using the hazard index (HI) for non-carcinogenic chemicals. Results: The harmful chemicals in college laboratories consisted of acetone, diethyl ether, methylene chloride, n-hexane, ethyl acetate, chloroform, tetrahydrofuran, toluene, and xylenes. They showed the highest concentrations in laboratories A (acetone 0.001~2.34ppm), B (chloroform 0.95~6.35ppm), C (diethyl ether 0.08~8.68ppm), and D (acetone 0.07~14.96ppm). The risk assessment result for non-carcinogenic chemicals showed that the HI of methylene chloride was 2.052 for men and 2.333 for women, the HI of N-hexane was 4.442 for men and 5.05 for women. Thus, the HI values were higher than 1. The risk of carcinogenic chemicals is determined by an excess cancer risk (ECR) value of 1.0×10^-5, which means that one in 100,000 people has a cancer risk. The ECRs of chloroform exceeded 1.0×10^-5 for both men and women, indicating the possibility of cancer risk. Conclusion: College laboratories showed the possibility of non-carcinogenic health risks for methylene chloride, n-hexane, tetrahydrofuran (THF), toluene, and xylenes, and carcinogenic health risks for chloroform, methylene chloride. However, this study used the maximum values of measurements to determine the worst case, and assumed that the subjects were exposed to the corresponding concentrations continuously for 8 hours per day for 300 days per year. In consideration of the nature of laboratory environment in which people are intermittently exposed, rather than continuously, to the chemicals, the results of this study has an element of overestimation.

• Journal of the Society of Disaster Information
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• v.18 no.1
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• pp.129-145
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• 2022

Purpose: This study aims at preparing an external evacuation system by setting up situation that may occur outside buildings in case of large-scale fire at buildings such as multiuse facilities and presenting appropriate response procedures and action instructions for evacuees and facility managers. Method: Major matters are summarized based on various situations which may occur outside in case of fire and the contents of fire manual. Necessary factors including risk alert standards in the event of fire and the role of building occupants are classified and then important issues are summarized. In addition, the definition of fire-related outside shelters and external evacuation routes are showed, and then the applicability to the shelters and the routes are reviewed for old apartments in Jung-gu among multi-dense facilities. Result: Four stages (attention, caution, alert, serious) for standards of fire risk warning are established with the results of the investigation and analysis, and guidelines for behavior for evacuees, facility owners, residents, managers are summarized and presented. In addition, the concept and role of external shelters are divided into primary to the third shelters, and matters related to the definition of each shelter and the establishment of evacuation routes are presented, and then considered them carefully. Conclusion: This study has highlighted the importance of suggesting a systematic plan to secure the safety for evacuees outside space of buildings with disorder and difficulty to control in the event of fire. Therefore, we are confident that it will be useful in making an integrated manual for inside and outside buildings.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.6
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• pp.896-903
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• 2021

For the safety assessment of microbiological and chemical hazards in raw short-neck clam Ruditapes philippinarum distributed in the Yeongnam and Honam areas during the spring season, the contamination levels of total viable bacteria, coliforms, Escherichia coli, and nine pathogenic bacteria (Staphylococcus aureus, Salmonella spp., Vibrio parahaemolyticus, Clostridium perfringens, Listeria monocytogenes, enterohemorrhagic Escherichia coli, Yersinia enterocolitica, Bacillus cereus, Campylobacter jejuni) as microbiological hazards, and heavy metals (lead, cadmium, total mercury), benzopyrene, shellfish poison (paralytic, diarrhetic, amnesic), and radioactivity (¹³¹I, ¹³⁴Cs+¹³⁷Cs) were also analyzed in 15 samples based on the methods of the Korean Food Code. The average contamination levels of total viable bacteria were 3.11 (1.40-4.49) log CFU/g, and coliforms were detected in 5 out of 15 samples (1.18-1.85 log CFU/g). E. coli and S. aureus were not detected in all samples. Furthermore, the presence of 8 pathogens were not detected in all samples. The average contamination levels of lead, cadmium, and total mercury were 0.155 (0.079-0.264), 0.160 (0.040-0.287), and 0.017 (0.008-0.026) mg/kg, respectively. Benzo(a)pyrene, shellfish poison, and radioactivity were not detected in all samples. The results of this study suggest that the safety against all microbiological and chemical hazard factors in raw short-neck clams distributed in markets has been assured.

• Korean Journal of Remote Sensing
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• v.38 no.5_2
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• pp.781-791
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• 2022

It is crucial to provide forest fire risk forecast information to minimize forest fire-related losses. In this research, forecast models of forest fire risk at a mid-range (with lead times up to 7 days) scale were developed considering past, present and future conditions (i.e., forest fire risk, drought, and weather) through random forest machine learning over South Korea. The models were developed using weather forecast data from the Global Data Assessment and Prediction System, historical and current Fire Risk Index (FRI) information, and environmental factors (i.e., elevation, forest fire hazard index, and drought index). Three schemes were examined: scheme 1 using historical values of FRI and drought index, scheme 2 using historical values of FRI only, and scheme 3 using the temporal patterns of FRI and drought index. The models showed high accuracy (Pearson correlation coefficient >0.8, relative root mean square error <10%), regardless of the lead times, resulting in a good agreement with actual forest fire events. The use of the historical FRI itself as an input variable rather than the trend of the historical FRI produced more accurate results, regardless of the drought index used.

• Journal of Appropriate Technology
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• v.7 no.2
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• pp.196-205
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• 2021

As industrial safety increases, various industrial accident prevention technologies using smart factory technology are being studied. However, small and medium enterprises (SMEs), which account for the majority of industrial accidents, are having difficulties in preventing industrial accidents by applying these smart factory technologies due to practical problems. In this study, customized monitoring and warning systems for each type of industrial accident were developed and applied to the actual field. Through this, we demonstrated industrial accident prevention technology through appropriate smart factory technology used by SMEs. A customized monitoring system using vision, current, temperature, and gas sensors was established for the four major disaster types: worker body access, short circuit and overcurrent, fire and burns due to high temperature, and emission of hazardous gas. In addition, a notification method suitable for each work environment was applied so that the monitored risk factors could be recognized quickly, and real-time data transmission and display enabled workers and managers to understand the disaster risk effectively. Through the application and demonstration of these appropriate smart factory technologies, the spread of these industrial safety technologies is to be discussed.

• Journal of the Korean earth science society
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• v.42 no.2
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• pp.164-174
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• 2021

The study examines the shearing and crushing characteristics of land-derived subaqueous granular materials in a gravel-bed river. A series of large-sized ring shear tests were performed to examine the effect of shear time and shear velocity on the shear stress characteristics of aquarium gravels with a 6-mm mean grain size. Three different shear velocities (i.e., 0.01, 0.1, and 1 mm/sec) were applied to measure the shear stress under the drained (long-term shearing) and undrained (short-term shearing) conditions. Different initial shear velocities, i.e., 0.01→0.1→1 mm/sec and 0.1→0.01→1 mm/sec, were considered in this study. The test results show that the grain crushing effect is significant regardless of drainage conditions. The shear stress of coarse-grained materials is influenced by initial shear velocities, regardless of the drainage conditions. In particular, particle breakage increases as grain size increases. The shearing time and initial shear velocity are the primary influencing factors determining the shear stress of gravels. The granular materials may be broken easily into particles through frictional resistance, such as abrasion, interlocking and fracture due to the particle-particle interaction, resulting in the high mobility of granular materials in a subaqueous environment.

• Journal of Chest Surgery
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• v.55 no.1
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• pp.10-19
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• 2022

Background: According to the eighth TNM (tumor-node-metastasis) staging system, the presence of separate tumor nodules in the same lobe is designated as a T3 descriptor. However, it remains unclear whether adjuvant chemotherapy confers survival advantages in this setting. Methods: We retrospectively identified 142 pathologic T3N0M0 patients with additional pulmonary nodules in the same lobe from a single-institutional database from 2004 to 2019. The main outcomes were overall survival and recurrence-free survival. Multivariable Cox regression was used to identify the benefit of adjuvant chemotherapy while adjusting for other variables. Results: Sixty-one patients received adjuvant chemotherapy (adjuvant group) and 81 patients did not receive adjuvant therapy after surgery (surgery-only group). There were no demonstrable differences between the 2 groups regarding hospital mortality and postoperative complications, indicating that treatment selection had not significantly occurred. However, the use of adjuvant chemotherapy was associated with improved 5-year overall survival (70% vs. 59%, p=0.006) and disease-free survival (60% vs. 46%, p=0.040). A multivariable Cox model demonstrated that adjuvant chemotherapy was associated with a survival advantage (adjusted hazard ratio, 0.54; p<0.001). In exploratory analyses of subgroups, the effect of adjuvant chemotherapy seemed to be insufficient in those with small main tumors (<4 cm). Conclusion: Adjuvant chemotherapy was associated with better survival in T3 cancers with an additional tumor nodule in the same lobe. However, the role of adjuvant chemotherapy in patient subgroups with small tumors or those without risk factors should be determined via large studies.