• 한국노년학
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• v.29 no.3
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• pp.837-850
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• 2009

Previous epidemiological studies reported that significant muscle loss is observed with advancing aging, called sarcopenia. This study is to investigate the effects of treatment dumbbell exercise on prevention of sarcopenia. The subjects were elderly between 60~70 years old who participated in J-Welfare senior center exercise program at J-gu in S-city and divided into control group(N=19) and exercise group(N=8). Treatment dumbbell exercise was performed 2 times per week for 12 weeks and body composition, fitness, and blood lipid profiles were measured before and after this program. There was no significance in body fat before and after 12 weeks of treatment dumbbell exercise, but there was significance in weight(F=4.312, p=0.048), BMI(F=4.532, p=0.043), and FFM(F=4.743, p=0.039). There was no significance in fitness such as arm curl(F=1.103, p=0.304), and back scratch(F=0.214, p=0.648), but there was significance in 2-minute step(F=33.638, p<0.001), chair stand(F=14.575, p=0.001), chair sit and reach(F=7.198, p=0.013), and 8-ft up and go(F=14.890, p=0.001). The variables of blood lipid profiles such as TC(F=0.030, p=0.864), TG(F=0.142, p=0.710), HDL(F=2.066, p=0.163), glucose (F=0.125, p=0.727), and HbA1c(F=0.945, p=0.340) has no significance. It was found that treatment dumbbell exercise has positive effects on body composition and fitness but has no positive effects on blood lipid profiles of the elderly.

• Korean Journal of Heritage: History & Science
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• v.56 no.3
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• pp.46-59
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• 2023

Various Baekje ground-level building sites have been identified, in Pungnaptoseong Fortress, including Mirae Village's site E-1. However, building site E-1 is the only one with excavated roof tiles that are directly connected to the building site. As for building sites E-2, D-1, and D-2, which are comparable to site E-1, it is very possible that they had tiles on the roof based on their jeoksim (blocking facilities for roof slopes) and building structures. Also, although they are semi-underground pit structures, pit building sites A-30 and modern apartment site A-5, as well as the No.44 remains of Gyeongdang District, which is closer to a ground-level type, the buildings with tiles may have been constructed in the form of partial tile roofs rather than full-face tile roofs. Therefore, there may be several reasons behind the use of tiles on roofs in the early days, but the primary background of the building's authoritative function would have been considered first. Considering that China and Japan started using tiles on nationally important buildings such as palaces, temples, and ritual buildings, it may be presumed that Baekje began using tiles from the time it centralized power. It is believed that Baekje's early roof tile buildings evolved from rudimentary residential architecture to advanced public architecture, taking into consideration fire prevention and structural stability in large buildings. It is difficult to find similar cases in Korea with structural features such as the elevated foundations or underground stone foundations that can be found in Mirae Village building site E-1. Rather, similar architectural techniques can be found in China and Japan. In China, similar construction techniques were discovered in buildings of worship that were primarily built in the palace surroundings, such as Jangan Castle. Based on this, it appears that roof tile building sites, such as site E-1, that have been discovered have a strong correlation with the characteristics of buildings of worship, and ground type buildings, such as sites D-1 and D-2, are important facilities that are related to important public facilities such as state-run warehouses. This provides many implications regarding the early Baekje city structure.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.7
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• pp.902-909
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• 2023

This study evaluated the performance test of a small-sized LTE-Maritime(LTE-M) transceiver that was developed and promoted to expand the use of intelligent maritime traf ic information services led by the Ministry of Oceans and Fisheries with the aim of supporting the prevention of maritime accidents. Accoriding to statistics, approximately 30% of all marine accidents in Korean water occur with ships weighing less than 3 tons. Therefore, the blind spots of maritime safety must be supplemented through the development of small-sized transceivers. The small transceiver may be used in fishing boats that are active near coastal waters and in water leisure equipment near the coastline. Therefore, verifying whether sufficient performance and stable communication quality are provided is necessary, considering the environment of their real usage. In this study, we reviewed the communication quality goals of the LTE-M network and the performance requirements of small-sized transceivers suggested by the Ministry of Oceans and Fisheries, and proposed a test plan to appropriately evaluate the performance of small-sized transceivers. The validity of the proposed test method was verified for six real-sea areas with a high frequency of marine accidents. Consequently, the downlink and uplink transmission speeds of the small-sized LTE-M transceiver showed performances of 9 Mbps or more and 3 Mbps or more, respectively. In addition, using the coverage analysis system, coverage of more than 95% and 100% were confirmed in the intensive management zone (0-30 km) and interesting zone (30-50 km), respectively. The performance evaluation method and test results proposed in this paper are expected to be used as reference materials for verifying the performance of transceivers, contributing to the spread of government-promoted e-navigation services and small-sized transceivers.

• Journal of Nutrition and Health
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• v.56 no.6
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• pp.667-682
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• 2023

Purpose: This study aimed to investigate the changes in health behavior, mental health, and nutritional status of Korean adolescents before and after the coronavirus disease 2019 (COVID-19) pandemic outbreak. Methods: A total of 800 adolescents (12~18 years old) who participated in the 2019-2020 Korea National Health and Nutrition Examination Survey (KNHANES) were included as study subjects and divided into four groups (204 middle school boys, 172 middle school girls, 219 high school boys, and 205 high school girls). The 2019 and 2020 KNHANES data were classified into data collected before and after the COVID-19 outbreak, respectively. Results: After the COVID-19 pandemic outbreak, middle school boys showed an increased tendency toward becoming overweight and obese, with significantly increased levels of diastolic blood pressure and insulin. While there was no major change in the subjective health status among adolescents, the high school boys showed a significantly decreased physical activity after COVID-19 outbreak. Moreover, the proportion of middle school students feeling a little stressed significantly increased after the COVID-19 outbreak. The rate of skipping breakfast significantly increased in middle school girls, but the rate of having lunch with companions significantly increased among all adolescents after the COVID-19 outbreak. However, the intake of milk, vegetables, fruits, seaweeds, and pulses significantly decreased, although the intake of sugars, beverages, and seasonings significantly decreased as well, during this period. These changes may lead to an increased proportion of adolescents with insufficient intake of nutrients, including potassium, vitamin C, and riboflavin. Conclusion: These results highlight the impact of COVID-19 on comprehensive changes in physical and mental health status, lifestyle behavior, and nutritional status in adolescents, suggesting the need for targeted prevention and intervention for physical and mental well-being during the pandemic.

• Land and Housing Review
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• v.14 no.4
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• pp.77-93
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• 2023

The COVID-19 pandemic has brought about significant social changes through government prevention and control measures, changes in people's risk perceptions, and lifestyle changes. In response, urban inhabitants changed their behaviors significantly, including their preferences for transportation modes and urban spaces in response to government quarantine policies and concerns over the potential risk of infection in urban spaces. These changes may have long-lasting effects on urban spaces beyond the COVID-19 pandemic or they may evolve and develop new forms. Therefore, this study aims to explore the potential for urban spaces to adapt to the present and future pandemics by examining changes in urban residents' preferences in travel modes and urban space use due to the COVID-19 pandemic. This study found that overall preferences for travel modes and urban spaces significantly differ between the pre-pandemic, pandemic, and post-pandemic periods. During the pandemic, preferences for travel modes and urban spaces has decreased, except for privately owned vehicles and green spaces, which are perceived to be safe from transmission, show more favorable than others. Post-pandemic preferences for travel modes and urban spaces are less favorable than pre-pandemic with urban spaces being five times less favorable than transportation. Although green spaces and medical facilities that were positively perceived during the pandemic are expected to return to the pre-pandemic preference level, other factors of urban spaces are facing a new-normal. The findings suggest that the COVID-19 pandemic has had a significant impact on urban residents' preferences for travel modes and urban space use. Understanding these changes is crucial for developing strategies to adapt to present and future pandemics and improve urban resilience.

• Journal of Life Science
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• v.33 no.10
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• pp.820-827
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• 2023

Since COVID-19 began at the end of 2019, the wearing time of protective clothing used to prevent pathogenic bacteria and virus infection has increased, and the development of safe protective materials that are human-friendly and have antibacterial and antiviral functions has been required. In this study, we investigated the possibility of developing natural antibacterial protection materials using ethanol extract of the medicinal plant Zanthoxylum Piperitum DC. The antibacterial activity assay of the 80% ethanol extract of Z. piperitum DC leaves against various nosocomial infectious bacteria, using the disk diffusion method, showed that Staphylococcus aureus ATCC 25923, Klebsiella pneumoniae ATCC 13883, Salmonella typhimurium, and Aeromonas hydrophila are sensitive to the inhibitory action of the extract. The IC₅₀ values of the ethanol extract against S. aureus, K. pneumoniae, P. vulgaris and A. hydrophila were about 0.59 mg/ml, 0.50 mg/ml, 1.06 mg/ml, and 0.06 mg/ml, respectively. To determine whether the ethanol extract of Z. piperitum DC leaves can be applied to the development of antibacterial protective fabric, the ethanol extract was tested using a protective fabric from the KM Health Care Corp. using the JIS L1902-Absorption method. As a result, the bacteriostatic and bactericidal activity values of S. aureus ATCC 25923 and K. pneumoniae ATCC 13883 appeared to be more than 2.0 when treated with the ethanol extract at a concentration of 1% (w/v). Together, these results suggest that Z. piperitum DC leaves can be applied to develop natural antibacterial functional protective fabrics.

• Journal of Life Science
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• v.33 no.12
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• pp.1002-1014
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• 2023

The root of Cirsium japonicum var. maackii (Maxim.) has long been used in traditional medicine to prevent the onset and progression of various diseases and has been reported to exert a wide range of physiological effects, including antioxidant activity. However, research on its effects on hepatocytes remains scarce. This study used the human hepatocellular carcinoma HepG2 cell line to investigate the antioxidant activity of ethanol extract of C. japonicum root (EECJ) on hepatocytes. Hydrogen peroxide (H₂O₂) was used to mimic oxidative stress. The results showed that EECJ significantly reverted the decrease in cell viability and suppressed the release of lactate dehydrogenase in HepG2 cells treated with H₂O₂. Moreover, an analysis of changes in cell morphology, flow cytometry, and microtubule-associated protein light chain 3 (LC3) expression showed that EECJ significantly inhibited HepG2 cell autophagy induced by H₂O₂. Furthermore, it attenuated H₂O₂-induced apoptosis and cell cycle disruption by blocking intracellular reactive oxygen species and mitochondrial superoxide production, indicating strong antioxidant activity. EECJ also restored the decreased levels of intracellular glutathione (GSH) and enhanced the expression and activity of superoxide dismutase and GSH peroxidase in H₂O₂-treated HepG2 cells. Although an analysis of the components contained in EECJ and in vivo validation using animal models are needed, these findings indicate that EECJ is a promising candidate for the prevention and treatment of oxidative stress-induced liver cell damage.

• Journal of Life Science
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• v.33 no.12
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• pp.1015-1024
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• 2023

Antibiotics have greatly contributed to the treatment and prevention of bacterial diseases in humans, animals, and fish. However, antibiotic misuse has led to the emergence and spread of multidrug-resistant bacteria. In addition to antibiotic discovery research, efforts are being made to combat such multidrug-resistant bacteria using antimicrobial agents, antioxidants, host immune enhancement, probiotics, and bacteriophages, as well as various symptomatic therapies. To discover novel bioactive compounds, it is crucial to adopt approaches that incorporate fresh ideas, new targets, innovative techniques, and untapped resources. Halophytes are plants that grow in high-salt soils and are known to adapt to salt-induced stress through unique metabolic processes that produce secondary metabolites. This study aimed to investigate the effects of extracts of halophytes native to Korea on oxidative stress and to determine whether they exert inhibitory activity against biofilms, which are major pathogenic factors of infectious bacteria. The Acinetobacter baumannii strain ATCC 17978, a representative drug-resistant bacterium, was used to measure anti-biofilm activity. The results showed that Aster spathulifolius, Carex kobomugi, Rosa rugosa, and Asparagus cochinchiensis exerted strong antioxidant and anti-biofilm effects without affecting bacterial growth itself. The halophytes used in this study are promising candidates for the development of pharmaceutical agents with antioxidant and antimicrobial properties.

• Korean Journal of Poultry Science
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• v.50 no.4
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• pp.231-240
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• 2023

Infectious bursal disease (IBD) is an acute, highly contagious, and immunosuppressive disease in young chickens, and causes considerable economic losses to the poultry industry. More than 30 years ago, an antigenic variant IBDV (avIBDV) was reported in chicken farms in the United States. Recently, a novel avIBDV exhibited clear differences in molecular characteristics compared with previous variant strains. This study investigated the molecular characteristics of recently isolated avIBDV strains in Korea. Strains of avIBDV were confirmed by reverse transcription PCR (RT-PCR) and were propagated in 10-day-old specific-pathogen-free (SPF) embryonated chicken eggs through chorioallantoic membrane (CAM) inoculation. Multiple sequence alignment and phylogenetic analyses of hypervariable regions VP2 gene revealed that the strains originated from two different avIBDV lineages (G2a and G2d). In our results, we confirmed the co-existence and prevalence of avIBDV genogroup G2a and G2d in chicken farms. It is necessary to study the protective efficacy of current vaccines against avIBDVs.

• Journal of Korea Water Resources Association
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• v.56 no.11
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• pp.751-764
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• 2023

Gangwon State is centered on the Taebaek Mountains with very different climate characteristics depending on the region, and localized heavy rainfall is a frequent occurrence. Heavy rain disasters have a short duration and high spatial and temporal variability, causing many casualties and property damage. In the last 10 years (2012~2021), the number of heavy rain disasters in Gangwon State was 28, with an average cost of 45.6 billion won. To reduce heavy rain disasters, it is necessary to establish a disaster management plan at the local level. In particular, the current criteria for heavy rain warnings are uniform and do not consider local characteristics. Therefore, this study aims to propose a heavy rainfall warning criteria that considers the threshold rainfall for the advisory areas located in Gangwon State. As a result of analyzing the representative value of threshold rainfall by advisory area, the Mean value was similar to the criteria for issuing a heavy rain warning, and it was selected as the criteria for a heavy rain warning in this study. The rainfall events of Typhoon Mitag in 2019, Typhoons Maysak and Haishen in 2020, and Typhoon Khanun in 2023 were applied as rainfall events to review the criteria for heavy rainfall warnings, as a result of Hit Rate accuracy verification, this study reflects the actual warning well with 72% in Gangneung Plain and 98% in Wonju. The criteria for heavy rain warnings in this study are the same as the crisis warning stages (Attention, Caution, Alert, and Danger), which are considered to be possible for preemptive rain disaster response. The results of this study are expected to complement the uniform decision-making system for responding to heavy rain disasters in the future and can be used as a basis for heavy rain warnings that consider disaster risk by region.