• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.4
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• pp.320-326
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• 2019

Recently, the application of atmospheric plasma technology in air filtration is increasing. Sterilization by an atmospheric plasma device is very effective. However, ozone gas, which is generated during atmospheric plasma formation, poses a hazard to human health. To reduce the ozone gas during plasma discharge, we fabricated a one-plate hybrid plasma discharge device with a heating element, which can decompose ozone gas effectively by a simple heating action. In this study, we evaluated the plasma discharge characteristics and ozone concentrations with various Ar flow rates and temperatures. With increasing Ar gas flow rate, the ozone concentration and spectrum intensity increased till an Ar gas flow rate of 60 sccm, and decreased thereafter. When discharged in high temperature, the ozone concentration and spectrum intensity decreased. Further, to evaluate the state of the treated surface under various plasma discharge and heating conditions, we measured the variation in the contact angles on the surface. Regardless of the temperature, the contact angle increased with increasing discharge voltage. However, the contact angle increased when discharged at high temperature.

• Journal of the Korean Dietetic Association
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• v.25 no.1
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• pp.30-43
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• 2019

This study compared the predictive models for the growth kinetics of Staphylococcus aureus in ham rice balls. In addition, a semi-quantitative risk assessment of S. aureus on ham rice balls was conducted using FDA-iRISK 4.0. The rice was rounded with chopped ham, which was mixed with mayonnaise (SHM), soy sauce (SHS), or gochujang (SHG), and was contaminated artificially with approximately $2.5{\log}\;CFU{\cdot}g^{-1}$ of S. aureus. The inoculated rice balls were then stored at $7^{\circ}C$, $15^{\circ}C$, and $25^{\circ}C$, and the number of viable S. aureus was counted. The lag phases duration (LPD) and maximum specific growth rate (SGR) were calculated using a Baranyi model as a primary model. The growth parameters were analyzed using the polynomial equation as a function of temperature. The LPD values of S. aureus decreased with increasing temperature in SHS and SHG. On the other hand, those in SHM did not show any trend with increasing temperature. The SGR positively correlated with temperature. Equations for LPD and SGR were developed and validated using $R^2$ values, which ranged from 0.9929 to 0.9999. In addition, the total DALYs (disability adjusted life years) per year in the ham rice balls with soy sauce and gochujang was greater than mayonnaise. These results could be used to calculate the expected number of illnesses, and set the hazard management method taking the DALY value for public health into account.

• Journal of Bone Metabolism
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• v.25 no.4
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• pp.267-274
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• 2018

Background: This prospective cohort study used nationwide claims data to investigate the incidence of fall and fragility fractures in association with urinary incontinence (UI) in the elderly, and to compare mortality after fragility fractures in elderly patients with or without incontinence. Methods: A total of 39,854 Korean adults (age, 66-80 years) who participated in health examinations between 2007 and 2012 and were followed up until 2015 were analyzed. Patient and comparison groups were classified according to the presence or absence of UI. The cumulative incidence of osteoporotic fragility fractures and falls in the 2 groups was assessed and compared. Hazard ratios for fragility fractures were calculated for the risk of UI in association with falls using a Cox proportional hazards model. Results: Of 39,854 elderly participants, 5,703 were classified in the UI group, while 34,151 were placed in the comparison group. Fall rates were significantly higher (20.8%) in the incontinence group than in the comparison group (4.7%) (P<0.001). Women in the incontinence group (13.9%) showed a significantly higher incidence of all types of fragility fractures than those in the comparison group (11.8%) (P=0.005). After adjustment for confounders, UI was not a significant risk factor for fragility fractures in men (P=0.878) or women (P=0.324). Conclusions: This study demonstrated that elderly women with UI have a significantly higher incidence of osteoporotic fragility fractures. In addition, elderly women are at higher risk for falls.

• Journal of Veterinary Clinics
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• v.36 no.1
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• pp.68-73
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• 2019

We determined the risk factors for displacement of the abomasum (DA), and the relationships between DA and postpartum disorders, milk yield, and reproductive performance in dairy cows. Initially, we identified the risk factors for DA using data regarding cow health and calving season from 2,208 lactations. Then, we compared the incidence of postpartum disorders, culling, death, and reproductive performance between cows with DA and their control herdmates (each n = 57). In addition, serum metabolites concentrations and milk yield were compared between cows with DA and controls (each n = 33). Ketosis (odds ratio [OR] = 9.27, p < 0.0001) and twin calves (p = 0.06) increased the risk of DA. Cows with a parity of three had a higher risk (OR = 5.23, p < 0.01) of DA than primiparous cows. Serum total cholesterol concentration was lower but non-esterified fatty acid, ${\beta}-hydroxybutyrate$, and alanine aminotransferase concentrations were higher after calving in cows with DA than in controls (p < 0.05). The removal rate from the herd by 2 months after calving was higher (p < 0.05) but milk yield 1 and 2 months after calving (p < 0.01) and the rate of first insemination by 150 days postpartum were lower (hazard ratio = 0.49, p < 0.05) in cows with DA than controls. In conclusion, higher parity, twin calves, and ketosis are risk factors for DA in dairy cows, which is associated with a higher removal rate from the herd, lower milk yield, a longer calving to first insemination interval, and unfavorable levels of metabolites related to energy and liver function.

• The Journal of Internal Korean Medicine
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• v.40 no.4
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• pp.597-611
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• 2019

Objective: The goals of this study were to analyze each of the reasons adopted by the Constitutional Court or the Courts for Decisions determined to permit the use of medical devices by Korean medicine doctors and to look at the medical devices from a Korean medical perspective. Materials and Methods: For this study, several judicial precedent databases were used for searching judicial precedents that handle the usage of medical devices by Korean medicine doctors. Prior studies on similar issues were considered. The Korean medicine textbooks and related research studies were also used in this study. Results: From 2000 to 2018, a large number of lawsuits were filed regarding the legality of Korean medicine doctors using medical devices; approximately 20 final judgments or decisions were made. Among them, only two cases determined that Korean medicine doctors could legally use medical devices. Conclusion: The decisions in both cases could be interpreted as the judgments that Korean medicine doctors were allowed to use a medical device whose use or operating principles were commonly incorporated with Korean medical principles. That was provided that training was sufficient in the use of the medical device, to the extent that it could be used and that such use of the medical device was not feared to pose a health hazard.

• Journal of Gynecologic Oncology
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• v.29 no.6
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• pp.82.1-82.13
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• 2018

Objective: The impact of beta blockers (BBs) on survival outcomes in ovarian cancer was investigated. Methods: By using Korean National Health Insurance Service Data, Cox proportional hazards regression was performed to analyze hazard ratios (HRs) with 95% confidence intervals (CIs) adjusting for confounding factors. Results: Among 866 eligible patients, 206 (23.8%) were BB users and 660 (76.2%) were non-users. Among the 206 BB users, 151 (73.3%) were non-selective beta blocker (NSBB) users and 105 (51.0%) were selective beta blocker (SBB) users. BB use in patients aged ${\geq}60$ years, longer duration use (${\geq}1$ year), in patients with Charlson Comorbidity Index (CCI) ${\geq}3$, and in cardiovascular disease including hypertension was associated with better survival outcome. These findings were observed in both NSBB and SBB. When duration of medication was analyzed based on number of days, NSBB (${\geq}180$ days) was associated with improved overall survival (OS) with a relatively shorter period of use compared to SBB (${\geq}720$ days). In multivariate Cox proportional hazards model, longer duration of BB medication (${\geq}1$ year) was an independent favorable prognostic factor for both OS and disease-specific survival in ovarian cancer patients. Conclusion: In our nationwide population-based cohort study, BB use was associated with better survival outcomes in ovarian cancer in cases of long term duration of use, in older patients, and in cardiovascular and/or other underlying disease (CCI ${\geq}3$).

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.4
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• pp.376-386
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• 2020

Objectives: This study identifies the trend of possible occupational disease and probable occupational disease in lead or cadmium workers. It is also required to check the usefulness of follow-up management in lead or cadmium workers by reviewing the relevance between the results of follow-up management and the trend of possible occupational disease and probable occupational disease. Methods: From 2009 to 2018, the results of the Ministry of Employment and Labor's special health-screening program for hazard agents for workers were used. The correlation between the ratio of possible occupational disease and probable occupational disease of lead or cadmium workers and the ratio of those who observed were and underwent observed follow-up management was analyzed to confirm the usefulness of follow-up management. Results: Over the past decade, the average annual proportion of possible occupational disease and probable occupational disease among lead workers has been on the decline. Among cadmium workers, it has generally shown a trend of increasing and decreasing. After the implementation of follow-up management, possible occupational disease in lead workers showed significant relevance to work prohibitions and restrictions, and probable occupational disease in lead workers showed significant relevance to the work prohibitions and restrictions, on-duty treatment, and boundary lines. However, there was no significant correlation between persons involved in cadmium workers. Conclusion: In this study, more active managements such as work ban and restrictions, on-duty treatment among follow-up management of possible occupational disease and probable occupational disease of lead worker and observers are related to a decrease in the ratio of those who have been diagnosed with possible occupational disease and probable occupational disease.

• Journal of the Korean Institute of Gas
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• v.25 no.1
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• pp.40-47
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• 2021

In this study, hazards of decomposition and explosion for tert-butylperoxymaleate(TBPM), an organic peroxide, were evaluated by using various equipment to determine the cause of a fire explosion accident. As a result of DSC analysis, the instantaneous power density of TBPM was 26,401 kW/ml, and the NFPA reactive index(Nr) was classified as 4. And the positive value of EP(explosive propagation) and SS(shock sensitivity) showed that the TBPM had a potential hazard of explosion. From the experimental results, the shock sensitivity and friction sensitivity was rated as class 4 and 5, respectively. In the pressure vessel test, TBPM was ranked USA-PVT No.4 and evaluated as a self-reactive substance. In the combustion rate test, TBPM had the combustion rate of 167 mm/sec and was evaluated as the flammable solid classification 2 in GHS.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.5
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• pp.514-523
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• 2022

Concentrations of perfluoroalkyl substances (PFASs) were measured in seawater, sediment, and biota collected from Gunsan coast, Korea to investigate their occurrence, distribution, and risk of exposure to humans through seafood consumption. The total concentrations of PFASs in seawater, sediment, and biota ranged from 5.97 to 74.9 ng/L, 0.01 to 13.3 ng/g dry weight, and 0.02 to 5.73 ng/g wet weight, respectively. Predominant PFAS compounds differed across matrices, indicating that the distribution of PFASs in multiple environmental samples is governed by their carbon-chain length. The concentrations of PFASs in seawater were significantly negatively correlated with salinity (P<0.01), suggesting terrestrial input (including land-used PFASs) as the major source of PFAS contamination in coastal environments. The estimated daily intakes (EDIs) of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) through seafood consumption were 0.05 and 0.06 ng/kg body weight/day, respectively. The EDIs of PFOA and PFOS measured in this study were lower those the proposed by the United States Environmental Protection Agency and Canada guidelines, indicating limited health risk for Korean population from PFASs through consumption of seafood from Gunsan coastal environment.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.163-170
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• 2021

The purpose of this study is to identify the harmful factors of teacher's job stress and occupational-related musculoskeletal diseases, and to investigate according to job types to seek solutions and improvement measures for removing harmful factors. A total of 168 elementary and high school teachers in Seoul were surveyed. As a result, the average RULA score of the teacher was 4.2 points, and the average RULA score of the teacher who did not complain of musculoskeletal diseases was 4.3 points. In addition, the average job stress score of the teacher was 58.9 points, and the stress score by factor was in the order of student guidance, work burden, loss of authority, organizational structure and curriculum, treatment and welfare, human relations. As a result of analyzing the teacher's RULA score and job stress, it was possible to derive a correlation between musculoskeletal disorders and job stress caused by occupation.