• Journal of dental hygiene science
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• v.23 no.4
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• pp.264-270
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• 2023

Background: Resin-based dental materials release residual monomers or other substances from incomplete polymerization into the oral cavity, thereby causing adverse biological effects on oral tissue. 10-Methacryloyloxydecyl dihydrogen phosphate (10-MDP), an acidic monomer containing dihydrogen phosphate and methacrylate groups, is the most commonly used component of resin-based dental materials, such as restorative composite resins, dentin adhesives, and resin cements. Although previous studies have reported the cytotoxicity and biocompatibility in various cultured cells, the effects of resin monomers on cellular aging have not been reported to date. Therefore, this study aimed to investigate the effects of the resin monomer 10-MDP on cellular senescence and inflamm-aging in vitro. Methods: After stimulation with 10-MDP, MC3T3-E1 osteoblast-like cells were examined for cell viability by WST-8 assay and reactive oxygen species (ROS) production by flow cytometry. The protein and mRNA levels of molecular markers of aging were determined by western blotting and RT-PCR analysis, respectively. Results: Treatment with 0.05 to 1 mM 10-MDP for 24 hours reduced the survival of MC3T3-E1 cells in a concentration-dependent manner. The intracellular ROS levels in the 10-MDP-treated experimental group were significantly higher than those in the control group. 10-MDP at a concentration of 0.1 mM increased p53, p16, and p21 protein levels. Additionally, an aging pattern was observed with blue staining due to intracellular senescence-associated beta-galactosidase activity. Treatment with 10-MDP increased the levels of tumor necrosis factor-α, interleukin (IL)-1β, IL-6 and IL-8, however their expression was decreased by mitogen-activated-protein-kinase (MAPK) inhibitors. Conclusion: Taken together, these results suggest that the exposure of osteoblast-like cells to the dental resin monomer 10-MDP, increases the level of cellular senescence and the inflammatory response is mediated by the MAPK pathway.

• Journal of Korean society of Dental Hygiene
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• v.23 no.5
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• pp.361-368
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• 2023

Objectives: This study investigated the oral health and quality of life of patients with hypertension using the raw data of the 8th National Health and Nutrition Examination Survey, the second year (2020) and 1,269 subjects were analyzed. Methods: The data underwent frequency analysis, descriptive statistics, general linear model analysis, and linear regression analysis using SPSS Statistics 26.0. Results: The quality of life (EuroQol-5 dimension: EQ-5D) of patients with hypertension was surveyed at 0.92 points/1 point. Quality of life according to general characteristics showed significant differences in gender (p<0.001), age (p<0.001), household income (p<0.001), and education level (p<0.001). Quality of life according to oral health showed significant differences in chewing discomfort (p<0.001), speaking discomfort (p<0.001), oral examination (p=0.004), toothache experience (p=0.020), subjective oral health (p<0.001) and oral care product use (p=0.006). Factors affecting quality of life were gender, age, household income, education level, chewing discomfort (B=-0.027, p=0.018), speaking discomfort (B=-0.049, p=0.026), toothache experience (B=-0.018, p=0.027) and subjective oral health (B=0.022, p<0.001). Conclusions: Based on the above results, it was confirmed that the oral health of patients with hypertension is a factor influencing the quality of life; thus, it is considered that it will be used as basic data for research on measures to improve oral health and quality of life.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.20 no.3
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• pp.139-146
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• 2010

Recent studies suggest that prolonged standing at work is associated with varicose veins (VV). The objective of this study was to analyze the differences of VV risk in terms of work types in casino dealers and hotel service workers. Symptoms of VV were evaluated using a self-reported questionnaire from 2,092 participants, and muscle fatigue in the lower legs were evaluated using surface electromyography. The shift rate of median frequency in Gastrocnemius was -30.0% among the casino dealers working in prolonged static standing posture, and - 14.3% among the casino dealers sitting during working time. After adjusting age, gender, smoking, and family history of VV, the risk ratio of VV was 3.67(95% CI 2.03-6.59) in group I (prolonged standing and occasional walking at work), 6.29(95% CI 3.48-11.35) in group II (prolonged standing, occasional walking and heavy lifting at work), and 8.07(95% CI 4.51-14.43) in groupIII(prolonged static standing at work). In conclusion, prolonged standing at work may be a work related risk factor of VV.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.20 no.4
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• pp.236-240
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• 2010

This study demonstrates the use of a chemical containing potassium superoxide (KO2) to convert carbon dioxide (CO$_2$) in air to oxygen (O$_2$). A oxygen generating closed-circuit SCBA (self contained breathing apparatus) removes carbon dioxide by a chemical reaction with potassium dioxide that consumes the carbon dioxide and produces oxygen. Considering the disasters, there is a need to develop strategies to enable the introduction of self-contained self rescuers (SCSR). The potassium superoxide reacts with the wears breath to produce oxygen and absorb carbon dioxide. If the respiration rate of a person is 5 MET (metabolic equivalent), to say 30 L/min, at disaster such as fire, mass of potassium superoxide was evaluated as 33.3 g with yield and safety factor. Four researchers tested on a laboratory treadmill breathing through SCSRs in a closed circuit, it appears useable for 9 minutes.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.23 no.3
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• pp.177-183
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• 2013

Objectives: 본 연구는 호흡보호구의 밀착도의 척도인 밀착계수 (FF)를 이용하여마스크에 마스크 커버를 씌웠을 때 호흡보호구의 밀착에 어떠한 영향을 미치는지 평가하고자 하였다. Methods: 3개 회사의 호흡보호구 (1개 1/4형, 2개 반면형)를 선정하여25의 피검자 (남자 16, 여자 9)에게 마스크 커버를 씌우지 않은 마스크와 씌운 마스크를 착용하게 하고 정량적인 밀착도 검사 (QNFT)를 실시하여 밀착계수 (FF)를 측정하였다. 동일한 조건에서 각 피검자에게 3번의 QNFT를 실시였으므로 한 마스크 당 씌운 것 75회, 씌우지 않은 것 75회, 150회를 시행하여 비교하였고 3개 마스크에 총 450회를 시행하였다. Results: 마스크 A (반면형)는 예상과는 다르게 마스크 커버가 있는 경우가 없는 경우보다 FF값이 더 높게 나왔으며 (p<0.05), 마스크 B (1/4형)와 마스크 C (반면형)은 마스크 커버가 없는 경우가 있는 경우보다 FF가 높게 나왔다. 마스크 B는 마스크 커버와 관계없이 FF가 너무 낮아 밀착에 문제가 있다고 판단되었으며 반대로 마스크 C는 마스크 커버에 영향을 받았으나 FF가 매우 높게 나와 밀착에는 큰 문제가 없다고 판단되었다. Conclusions: 본 연구 결과는 마스크에 자신의 마스크 커버를 씌울 경우 밀착에 큰 영향은 없는 것으로 나타났으나 FF만 가지고 실험했기 때문에 제한적이며 실제 작업현장에서 밀착도에 영향을 주지 않는지를 결정하기 위해서는 작업장보호계수 (WPF)를 이용한 보다 많은 연구가 필요하다.

• The Korean Journal of Health Service Management
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• v.11 no.2
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• pp.81-91
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• 2017

Objectives : The purpose of this study was to provide basic data for the development of general and oral health improvement programs for the elderly by analyzing the effect of health risk factors on the remaining teeth of the elderly in day care centers. Methods : The subjects were 294 elderly people who used day care centers in Seoul. Results : In terms of health risk factors, the elderly who did not have diabetes or smoke had more remaining teeth. In terms of oral health risk factors, the elderly with no dental caries, periodontal disease and dental pain had more remaining teeth. Conclusions : It is necessary to activate systematic welfare services for the elderly that fit their lifestyle in the light of the health and oral health risk factors of the elderly who use day care centers.

• Journal of Food Hygiene and Safety
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• v.9 no.3
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• pp.133-139
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• 1994

The pyrolytic formation of benzo[a]pyrene during the cooking procedure was analysed in beef, pork, pacific saury, rice, and soybean by HPLC. In raw foods, benzo[a]pyrene (B[a]P) was not detected or negligible, but it was increasingly formed when foods were boiled (0.010~0.037 ppb) and more dramatically during broiling (0.302~0.851 ppb) in a time dependent manner. Human daily intake of B[a]P in Koreans and cancer risk assessment were estimated based on food consumption per capita and carcinogenic potency of B[a]P. When cooked foods were consumed for entire life time, cancer risk was estimated to bo 1.77$\times$10-6>1.65$\times$10-7>1.32$\times$10-8 by the order of broiled, boiled, and raw foods consumption. These data suggest that broiled foods produce more benzo[a]pyrene than water boiled foods. Thus cooking procedure is an important factor for the formation of carcinogens and needs to bo modified to reduce cancer risk for man.

• 한국경영정보학회:학술대회논문집
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• 2008.06a
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• pp.400-410
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• 2008

As the number of blog users has been increasing significantly, a lot of studies have been carried out to find out what makes people use a blog or feel satisfied with it. However, most of the previous studies assumed that dissatisfaction is the opposite of satisfaction and a person who is dissatisfied with a blog does not use it, failing to explain about blog users who do not feel satisfied with their blogs but use them continually. In addition, the studies found out just blog users' motives and satisfying factors in using blogs, and did not suggest any way to improve and promote blog services. Against this backdrop, this study conducted a survey of blog users in order to examine how the satisfying factors of a blog selected through a prior study affect both satisfaction and dissatisfaction of a user. The survey results showed that the satisfying factors are divided into two groups: group A which affect satisfaction and dissatisfaction equally, and group B which affect them differently. Based on the results, this study subdivides group A into high involvement factors and low involvement ones, and group B into motivators, which strongly affect satisfaction, and hygiene factors, which strongly affect dissatisfaction. According to characteristics of each group, this study suggests ways to improve and promote blog services.

• Journal of Food Hygiene and Safety
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• v.16 no.2
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• pp.133-138
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• 2001

Toxicological safety on 20 kGy-gamma irradiated Kanjang (soy sauce), Doenjang (soybean paste), Kochujang (hot pepper paste) and Chunghukjang (soy paste) was determined by SOS Chromotest. As the strain of the SOS Chromotest, Escherichia coli PQ37 was used in the condition of presence or absence of an exogenous metabolizing system (S-9 mix). Water extract or organic solvent extract was prepared from samples, concentrated and tested by SOS Chromotest with S-9 mix or not. All irradiated samples were not different from non-irradiated one in the bacterial assay maintaining the below 1.5 of IF(induction factor) values in the adapted dose of 10,000$\mu\textrm{g}$/assay. The results indicated that any mutagenicity was not observed in 20 kGy-irradiated traditional soybean fermented foods.

• Journal of Food Hygiene and Safety
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• v.10 no.2
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• pp.81-87
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• 1995

Daily exposure of aflatoxin B1 (AFB1) was estimated in foods (rice, barley, soybean, peanut, soysauce, soybean paste) by ELISA (enzyme linked immunosorbent assay) using polyclonal antibody R101. Before ELISA, a simple extraction method was applied for the quantitation of AFB1 in foods using chloroform which showed high recovery (70$\pm$12%). AFB1 levels in foods were 0.32 ng/ml (rice), 0.24ng/ml (barley), 0.22 ng/ml (peanut), 0.30~0.78 ng/ml (soysauce), and 0.2 ng/ml (soybean paste). Based on food consumption, we estimated that Koreans were exposed to AFB1 at the level of 1.86$\pm$0.46 ng/kg/day and liver cancer incidence attributed to AFB1 exposure (assuming that AFB1 as a single hepatocarcinogenic agent) might be calculated to be 13.1 per 100, 000 population. Our data demonstrate that AFB1 levels in foods were below the regulation of 10 ppb in foods and might not be the major risk factor for the high incidence of lover cancer in Korea.