• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.31 no.2
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• pp.173-183
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• 2021

Objectives: This study evaluated the skin permeability of lawsone in henna hair dyes to understand the exposure characteristics of henna hair dyes in the human body. It examined the protective effects of protectants by applying protectants A, B, and C to test skin. Methods: Skin absorption tests were conducted using Franz diffusion cells according to OECD test guideline 428. After applying one kind of natural henna hair dye and chemical henna hair dye, respectively, to a standardized pig skin model, samples of receptor fluid were collected at 1h, 3h, 6h, and 24h. The skin permeation of lawsone was determined using HPLC. After the skin absorption experiment, the skin to which hair dye was applied was analyzed to determine the residual amount of lawsone in the skin. Results: The cumulative permeation of both natural and chemical henna hair dyes increased over time, and the natural henna hair dye had a flux value (t=3.194, p<.05) high both in the K_p value (t=3.207, p<.05) and the residual amount (t=22.701, p<.001). For skin treated with a protectant, the cumulative permeation of natural henna hair dye 24h control and the cumulative permeation of protectant A, B, and C increased over time. Flux and K_p values were in the order control > protectant A > protectant C > protectant B. The residual amount (F=4.469, p<.05) was in the order of protectant C > protectant A > protectant B > control. At 3h, the dye application time of natural henna hair dye, the lawsone flux value (F=4.454, p<.05) and K_p value (F=4.455, p<.05) were higher in the control group than in the protectant groups. The 24h cumulative permeation of the chemical henna hair dye increased with time in both the control and the protectant groups, and the flux and K_p values were in the order of protectant A > protectant C > protectant B > control. The residual amount (F=7.901, p<.01) was in the order of protectant B > protectant A> protectant C > control. Conclusions: Within the normal dyeing time for henna hair dye (three hours for natural henna hair dyes and 30 minutes for chemical henna hair dyes) lawsone skin penetration was not observed even when no protective agent was applied. After that time, however, evidence of skin penetration and retention of lawsone and the protective effect of protective agents were observed.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.31 no.2
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• pp.138-146
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• 2021

Objectives: This study aims to compare and evaluate the reduction efficiency of disinfectants used in the domestic meat processing industry to reduce bioaerosol exposure of meat industry workers and to use this as basic data for establishing work environment management measures. Methods: Thirteen disinfectants sold in South Korea were selected for evaluation and the bacterial reduction effect of the disinfectants was investigated. Bacterial suspension and surface disinfection tests were conducted to compare and analyze the antibacterial strength of the disinfectants. Pork carcasses, cutting boards, benches, and conveyor belts were selected for surface sterilization tests. Results: As a result of the bacterial suspension experiment test, all disinfectants had a bacterial reduction efficiency of more than 86%. Among them, the bacterial reduction efficiency of chlorine disinfectants was 99.93% on average. In the results of the pork carcass surface sterilization test, the rate of reduction of disinfectants made of quaternary ammonium compounds (QACs) was the highest. Tests of plastic cutting boards showed that chlorine disinfectants had the best sterilization effect. Experiments on stainless steel benches showed the best bacterial reduction efficiency for chlorine dioxide and QACs disinfectants. In the conveyor belt made of urethane, QACs disinfectants showed excellent sterilization effects. Conclusions: The study evaluated the disinfection power of disinfectants against bacteria occurring in domestic meat processing plants. All disinfectants were found to be effective in bacterial suspension experiments, and chlorine disinfectants were particularly effective. In surface sterilization experiments, sterilizing agents with QACs as the main ingredient were excellent.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.4
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• pp.571-580
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• 2020

In this study, an experimental study on storage media for thermal energy storage system was conducted. For thermal energy storage medium, concrete has excellent thermal and mechanical properties and also has various advantages due to its low cost. In addition, the ultra-high strength concrete reinforced by steel fibers exhibits excellent durability against exposure to high temperatures due to its high toughness and high strength characteristics. Moreover, the high thermal conductivity of steel fibers has an advantageous effect on heat storage and heat dissipation. Therefore, to investigate the temperature distribution characteristics of ultra-high-strength concrete, concrete blocks were fabricated and a heating test was performed by applying high-temperature thermal cycles. The heat transfer pipe was buried in the center of the concrete block for heat transfer by heat fluid flow. In order to explore the temperature distribution characteristics according to different shapes of the heat transfer pipe, a round pipe and a longitudinal fin pipe were used. The temperature distribution at the differnent thermal cycles were analyzed, and the thermal energy and the cumulated thermal energy over time were calculated and analyzed for comparison based on test results.

• The Journal of the Korea Contents Association
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• v.21 no.11
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• pp.490-502
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• 2021

Horticultural facility farmers subscribe to crop accident insurance and insurance products secured by horticultural facilities in preparation for possible risks in the facility. Insurance is purchased to prepare for natural disasters such as typhoons, hail, frostbite, heavy rain, and strong wind damage covered by the product. In order to find out the effect of risk perception, which is a subjective perception of the risks of a given situation, on horticultural facility farmers' intention to purchase horticultural facility insurance products, the risk perception and insurance purchase intention were analyzed. A t-test was conducted to determine the impact relationship between farm size, insurance coverage, and risk perception, and multiple regression analysis was conducted to verify the effect of personal characteristics and behavioral factors such as subjective perception, reference group, media exposure, and compensation understanding. In addition, a three-step regression analysis by Baron & Kenny was conducted to confirm the mediating role of personal characteristics and behavioral factors in the relationship between risk perception and insurance purchase intention. As a result of the study, although there was no difference in farm size, it was analyzed that policy holders had a higher degree of risk perception than non-subscribers, and that compensation understanding had the greatest influence and subjective knowledge had the smallest influence. In addition, these four factors were verified to have a mediating effect on the relationship between risk perception and insurance purchase intention. These results are expected to provide practical help to the development and marketing activities of horticultural facility insurance products.

• Journal of the Korean Society of Radiology
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• v.16 no.1
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• pp.7-13
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• 2022

This study compared the aortic root image by using the ECG gating and non-ECG gating methods. We observed the presence or absence of progression of the aortic root image in the images examined by the high pitch (flash) chest pain protocol method and in the patients tested without ECG gating by the conventional method. The AAPM phantom was scanned by using high pitch (flash) chest pain protocol and general chest pain protocol. CTDI values were compared. By ECG gating, the blurring of ascending aorta was significantly reduced compared to the existing non-ECG gating test method, and the image quality of the aortic root was improved. Within the parametar range that did not show differences in noise, uniformity, and high contrast resolution, CTDI values were lower when tested with the high-pitch chest pain protocol. It was found that there is an advantage in dose reduction, and if it is applied and applied to diagnostic fields such as dissection using the dose reduction mode in the cardiac field, it is a very important test for patients who need rapid diagnosis and prompt treatment as well as a dramatic reduction in exposure dose. It is presumed to be a method.

• Journal of the Korean Society of Radiology
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• v.16 no.4
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• pp.381-386
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• 2022

Non-Destruction Test (NDT) is a method to check internal defects without destroying the product. Among them, radiographic testing (RT) uses high-energy radiation, so it is very important to prevent radiation exposure of workers. Therefore, in this study, in this study, a radiation sensor structure that improves radiation detection performance compared to the existing PbI₂ and can immediately detect accidents in RT was presented. For evaluation, the conversion efficiency was analyzed in the gamma ray source through FLUKA simulation. PbI₂ with overlapping Gd₂O₂S:Tb presented in this study showed a higher radiation sensitivity from 1.22 to 3.22 times than that of non-overlapping PbI₂. This indicates that the presented sensor is suitable for use as a radiation sensor for source detection in RT.

• Journal of Environmental Health Sciences
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• v.48 no.6
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• pp.306-314
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• 2022

Background: Due to the rapid aging of the South Korean population, neurological diseases such as dementia are increasing. Many studies have reported that the incidence of dementia is associated with environmental factors along with age. Objectives: This study analyzed the association between cognitive function and ten heavy metals in the body: arsenic, aluminum, chromium, manganese, cobalt, nickel, iron, copper, zinc, and lead. Methods: From 2018 to 2019, a total of 120 participants who suffered from cognitive impairment were recruited for this study. Blood and urine samples were collected and analyzed for heavy metal concentrations using an inductively coupled plasma mass spectrometer. Demographic information was obtained through face-to-face questionnaires completed by a trained investigator. Cognitive function was evaluated with the Korean version of the Mini-Mental State Examination and the Korean version of the Boston Name Waiting Test. The associations between cognitive function scores and heavy metal concentrations were analyzed using multiple logistic regression analysis. Results: The average age of the 120 participants was 72.7 years, and 69.2% were female. The mean of the MMSE-K and K-BNT scores were 22.9 and 37.9, respectively. The geometric mean of aluminum (Al) was 8.42 ㎍/L. MMSE-K was associated with iron (Fe), but the significance was removed in the logistic regression based on 24 points. K-BNT was significantly associated with aluminum and the odds ratio for K-BNT above 38 decreased by 45% as the aluminum concentration increased. Conclusions: The association between aluminum and the K-BNT score indicated that aluminum is associated with language-related cognitive decline. Based on this result, further study will be conducted by considering co-exposure effects of heavy metals including aluminum.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.4
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• pp.331-344
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• 2023

The performance of the existing tunnel scanning system was analyzed through the post-evaluation of NETIS (New Technology Information System) and Inspection Support Technology Performance Catalog. Suggestions for improvement and development direction of the tunnel scanning system were deduced. As new technology of Japan gave priority to providing user-centered information, it was possible to objectively compare and analyze the characteristics of various tunnel scan systems through post-evaluation of NETIS and standard test methods in the Inspection Support Technology Performance Catalog. Construction New Technology of Korea was centered on suppliers of technology certification, making it impossible to objectively compare the performance of tunnel scanning systems. The performance was compared and evaluated indirectly by comparing the specifications of the camera, which is a core device of Japan's tunnel scanning system. For the future development of tunnel scanning systems, high-resolution and fast exposure performance of cameras and corresponding high-intensity lighting devices are required. For this purpose, it is necessary to make an experimental environment in which the performance of the camera and lighting can be analyzed indoors.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.49 no.4
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• pp.349-354
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• 2023

Sunscreen is a product that protects against ultraviolet rays by blocking and scattering ultraviolet rays, and has now become a daily necessity beyond cosmetics. Applying sunscreen is a common and easy way to prevent skin damage caused by ultraviolet rays. Due to its significance, the evaluation of sunscreen has evolved since its regulation by the FDA in 1978, progressing to standardized methods established by ISO. Additionally, to assess the loss of sunscreen due to activities such as water exposure or sweating, the Ministry of Food and Drug Safety in Korea and ISO have established protocols for evaluating the water-resistant sun protection factor (SPF). However, existing evaluations of water resistance have been mainly confined to test methods involving plain water, and methods accounting for the impact of seawater during activities like beach leisure, sports, and recreation are yet to be established. Based on the existing guidelines for testing the water-resistant UV protection index, this study compared the water-resistant UV protection index in water, artificial seawater (salt water) and natural seawater (sea water) to evaluate the UV protection index in real-world situations such as marine leisure, sports, and leisure activities. Through these results, we were able to compare the differences between water resistance sun protection index tests in ordinary water, artificial seawater, and natural seawater, and suggest a method for water resistance sun protection index tests using natural seawater.

• Journal of Society of Preventive Korean Medicine
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• v.28 no.2
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• pp.55-65
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• 2024

Background : Tuberculosis (TB) remains a significant public health issue worldwide, particularly among healthcare workers (HCWs) at high risk of exposure. Latent tuberculosis infection (LTBI) is a state where individuals are infected with Mycobacterium tuberculosis but do not show clinical symptoms. Early detection and treatment of LTBI are crucial to prevent progression to active TB. This study aimed to investigate the prevalence and risk factors of LTBI among Korean Medicine (KM) workers in Seoul, South Korea. Methods : This study analyzed 368 adults aged 19 and over working in Korean medicine institutions in Seoul by September 2023. Participants underwent a tuberculin skin test (TST) and completed a survey collecting demographic information, occupation, work duration, smoking status, BCG vaccination, TB history, and comorbidities. Data were analyzed using descriptive statistics and chi-square tests, with significance set at p < 0.05. Results : The average age of participants was 43.1 years, with an LTBI prevalence rate of 3.5%. Significant risk factors included age and history of TB, Older age and a history of TB were associated with higher LTBI positivity. Conclusion : The study identified the prevalence and risk factors of LTBI among Korean medicine workers in Seoul. The findings highlight the need for targeted LTBI screening and preventive measures, especially for older workers and those with a history of TB. While the prevalence was lower than in other healthcare settings, the results emphasize the importance of regular LTBI testing and prevention education for KM workers. Future large-scale studies are needed to confirm these findings and further understand the relationship between various risk factors and LTBI in KM settings.