• Korean Journal of Clinical Laboratory Science
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• v.37 no.1
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• pp.47-55
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• 2005

These studies were done to know decalcification methods to reduce the time of decalcification for quick bone tissue diagnosis. When bone tissue was decalcified with 10 % formic acid at room temperature, decalcification and hematoxylin & eosin (H&E) stains were complete and satisfactory after 12 hours, but some of the tissue sections fell off during staining. In this way, decalcification, H&E stains were complete and satisfactory after 24 hours, 36 hours and 48 hours, tissue sections didn't fall off during staining. When bone tissue was decalcified with 10 % formic acid in a $60^{\circ}C$ paraffin oven, decalcification and H&E stains were complete and satisfactory after 6 hours, but some tissue sections fell off during staining. In this way, decalcification and tissue sections were complete, with no falling off during staining after 8 hours, 10 hours, 12 hours, 14 hours, 24 hours, or H&E stains were satisfactory from 8 hours to 12 hours, but H&E stains appeared to reddish nucleus after 14 hours and 24 hours. Bone tissue was decalcified with 10 % formic acid for 6 hours, 12 hours and 24 hours at DECAL machine frequencies of 15 Hz and 45 Hz, and for 6 hours, 12 hours and 24 hours at a DECAL machine frequency of 90 Hz. Decalcification and H&E stains were complete and satisfactory after 6 hours at the 15 Hz and 45 Hz DECAL settings. Some of the tissue sections fell off during staining at the 15 Hz DECAL machine setting. At the 90 Hz setting, decalcification, H&E stains, and tissue sections were complete and satisfactory with no falling off during staining after 4 hours. In this way, decalcification, H&E stains, and tissue section were complete and satisfactory with no falling off during staining after 12 hours, 24 hours at all machine settings. Bone tissue was decalcified with 10 % formic acid for 6 hours, 12 hours and 24 hours at $37^{\circ}C$ 3 hours, 6 hours and 12 hours at $45^{\circ}C$ and 1 hours, 5 hours and 10 hours at $60^{\circ}C$ with the RHS-1 machine setting at 60Hz. At the temperatures of $37^{\circ}C$, $45^{\circ}C$, and $60^{\circ}C$ decalcification, H&E stains, and tissue sections were complete and satisfactory, with no falling off during staining except for after 6 hours at $37^{\circ}C$. 3 hours, 1 hours, or decalcification, H&E stains, and tissue sections were complete and satisfactory with no falling off during staining after 12 hours and 24 hours at $37^{\circ}C$, 6 hours and 12 hours at $45^{\circ}C$, and 5 hours at $60^{\circ}C$. But H&E stains appeared to reddish nucleus after 10 hours at $60^{\circ}C$. From the above reults, the authors were able to deduce that decalcification is accelerated by heat and frequency. We therefore think that it is necessary for machines which are similar to the RHS-1 machine to be maintained at the temperature evenly with agitation effect for quick decalcification.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.2
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• pp.236-243
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• 2015

Objectives: This study sought to examine the association between long working hours and depressive symptoms among interns and residents in South Korea. Methods: We analyzed a cross-sectional survey of 1,661 interns and residents from the 2014 Korean Interns & Residents Survey. Total working hours during the preceding week was assessed and classified into five categories(i.e. less than 60 hours, 60-79 hours, 80-99 hours, 100-119 hours, and 120-168 hours). Depressive symptoms during the previous week were measured by using ten items from the Center for Epidemiologic Studies Depression Scale questionnaire. Multivariate negative binomial regression was applied to examine the association between long working hours and depressive symptoms after adjusting for potential confounders, including medical specialty and training year. All analyses were performed using STATA/SE version 13.0. Results: 86%(N=1,429) of interns and residents worked 60 hours or more per week. Compared to the "less than 60 hours" group, long working hours for interns and residents were significantly associated with depressive symptoms: "60-79 hours"(PR: 1.56, 95% CI: 1.05, 2.32), "80-99 hours"(PR: 2.27, 95% CI: 1.54, 3.33), "100-119 hours"(PR: 2.62, 95% CI: 1.76, 3.89), and "120-168 hours"(PR: 3.28, 95% CI: 2.21, 4.86). Conclusions: This study found that long working hours were prevalent among interns and residents in South Korea, and it was associated with depressive symptoms.

• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.21.1-21.11
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• 2023

Background: Recently, irregular working hours have become controversial issues in Korea. The health impact of irregular working hours on the work-related musculoskeletal pain (MSP) is scarcely researched before. We sought to investigate the association between irregular working hours and work-related MSP among South Korean workers. Methods: This study used data from the sixth Korean Working Conditions Survey in 2020. The prevalence of work-related MSP was analyzed using the χ² test. A multiple logistic regression analysis was conducted to assess the association between irregular working hours and work-related MSP. We conducted stratified analysis by gender, weekly working hours, and workers' control over their working hours. We calculated the adjusted odds ratios (ORs) of work-related MSP for irregular working hours combined with weekly working hours. Results: The OR for work-related MSP was significantly higher in the population with irregular working hours than in the population with regular working hours (OR: 1.43, 95% confidence interval [CI]: 1.29-1.58). Irregular and long (> 52 hours/week) working hours have the highest risk of work-related MSP in both genders (in men, OR: 3.48 [95% CI: 2.53-4.78]; in women, OR: 2.41 [95% CI: 1.46-4.00]). Conclusions: Irregular working hours were associated with work-related MSP in Korea. The association was magnified with long working hours. Reform of the Korean Labor Standards Act leading to increase irregular working hours may induce adverse health outcome.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.20 no.2
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• pp.171-182
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• 1990

The purpose of this study was to investigate the effects of irradiation on the striated duct cells of the rat submandibular gland ductal tissues which control the characteristics of saliva. For this study, the experimental group was composed of 36 irradiated Sprague Dawley strain rats divided into 8 subgroups 1 hour, 2 hours, 3 hours, 6 hours, 12 hours, 24 hours, 48 hours, 72 hours after irradiation. 4 non-irradiated rats were used as the control group. The experimental animals were singly irradiated with a dose of 18Gy gamma ray to their head and neck region by the Co-6- teletherapy unit and sacrificed after each experimental duration. The specimens were examined with a light microscope with an H-E stain and with a trans- mission electron microscope. The results of this study were as follows. In the light micrograph, a severe atrophic change occurred in the striated duct cells at 2hours after irradiation and gradual recovery occurred from 6 hours after irradiation. 2. The nuclear chromosomes of the striated duct cells were changed granular at 2 hours after irradiation. Recovery was observed at 6 hours after irradiation. Nuclear bodies were also observed from 3 hours after irradiation. 3. The mitochondria of the striated duct cells had indistinct cristae at 2 hours after irradiation, and were degenerated or swollen at 3 hours after irradiation. They recovered, however, from 6 hours, with an increasing number at 48 hours and a regular arrangement was observed at 72 hours after irradiation. 4. The microvilli showed atrophic changes at 2 hours after irradiation and were almost lost at 3 hours after irradiation. They were observed again from 48 hours after irradiation. 5. The rough endoplasmic reticulum and golgi body were not apparent at 1 hour after irradiation and were dilated with degeneration 2 hours after, but intact rough endoplasmic reticulum were observed from 3 hours after irradiation and developed well at 24 hours after irradiation. By the result of this study, showing a mild change in the functional morphology of the salivary striated duct cells immediately following irradiation, it is considered that the many complications which occur after radiation therapy, will disappear in time with the histological and the functional recovery of the glandular tissues.

• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.19.1-19.5
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• 2023

There are several types of shift work in Korea: rotating shift, 24-hour shift, day-night shift, fixed night work, and.so on. As a result of analyzing the 8th Korea National Health and Nutrition Examination Survey and the 6th Korean Working Condition Survey, Korean shift workers accounted for 11.6%-13.9% of wage workers. Weekly working hours of shift workers were 57.69 ± 1.73 (24-hours shift) and 49.97 ± 0.67 (fixed night shift), which were significantly longer than day workers. To prevent health consequences of night work, many countries regulate the working hours of night work not to exceed 7-9 hours a day. However, Korea does not regulate working hours for night work, and some occupations may work more hours than the prescribed overtime hours. To prevent health consequences and reduce working hours for Korean night shift workers, it is necessary to regulate the working hours of night shift workers by law.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.2 no.2
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• pp.199-211
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• 1995

This study analyzed the practical education in fundamentals of nursing, for the 36 nursing schools including 12 4-year nursing schools and 24 junior college nursing schools. This survey was done from september 5th to october 5th in 1995. The results of this study were as follows : 1. Required credit in fundamentals of nursing. 1) The highest incidence of the total required credit was 7 in 4-year nursing school and 9 in junior college. 2) For the lecture course credit, the large number of 4-year nursing school gave 5 credit lessons and 6 credits provided in junior nursing colleges. 3) For the credit of practical education the major portion of 4-year nursing school gave 2 credits instruction, however junior nursing school provided 3 credits. 2. Laboratory practice in fundamentals of nursing. In laboratory practice, the ratio of instructor and student was 1 : 20 in 83.4% of the 4-year nursing school and in 66.7% of the junior nursing school. 3. Contents and hours of fundamental nursing practice. 1) In the area of health assessment and nursing process, the large number of schools allocated following hours : 6 hours for vital signs, 4 hours for nursing process, 2 hours for recording but practice for physical examination and communication was done in few schools. 2) In the area of functional health pattern, the large number of schools allocated practice hours like followings : 2 hours for I/O, 2 hours for gavage feeding, 2 hours for elimination, 6 hours for catheterization, 6 hours for bed making, 2 hours for positioning, 6 hours for personal hygiene, 2 hours for R.O.M, 4 hours for moving turning lifting, 2 hours for inhalation and suction. But C.P.R and terminally ill patient care were taught in smaller number of schools. 3) In the area of special nursing measures, the major portion of nursing schools allocated hours like followings. It consisted of 6 hours for asepsis, 16-18 hours for medication, 2 hours for heat and cold application, 2 hours for wound care. 4) 22.2% of the nursing schools had total review practice time and 36.1% of the nursing schools had the students clinical practice. Based on above mentioned results, 4-year nursing school had faithful practical education of fundamental nursing than junior nursing school. But for the contents and allocated hours for practice education, junior nursing schools were much more contents and hours than 4 year school.

• Journal of the Korean Dietetic Association
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• v.28 no.1
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• pp.1-18
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• 2022

This study was conducted to estimate the appropriate workforce of dietitians by type of kindergarten through the recognition survey and job analysis of the kindergarten. Nutritionists' duties were classified into 6 duties, 28 tasks and 94 task elements. The statistical data analysis was completed using Statistical Package for the Social Sciences (SPSS) (ver. 25.0). The time spent on 6 duties, including 'Nutrition management' (public attached 666.24 hours/year, public independent 843.04 hours/year), 'Foodservice management Practices' (public attached 1,472.52 hours/year, public independent 1,298.11 hours/year), 'Hygiene management of kindergarten foodservice' (public attached 611.78 hours/year, public independent 607.18 hours/year), 'Nutrition-diet education and counseling' (public attached 340.53 hours/year, public independent 253.42 hours/year), 'Managing snack during semesters and lunch/snacks during breaks' (public independent 309.04 hours/year) and 'Professionalism enhancement' (public attached 88.86 hours/year; public independent 65.17 hours/year). Total working hours for dietitians were 3,179.94 hours/year (public attached) and 3,375.97 hours/year (public independent). The time/day ×5 days/week ×52 weeks/year calculation method using derived total working hours/year was applied to derive appropriate full-time equivalents (FTEs). The analysis showed that the public attached kindergarten's FTEs were 1.53. The public independent's FTEs were 1.62, and the total FTEs were 1.55. This is the first study to analyze the workload of kindergarten dietitians and appropriate manpower by kindergarten establishment type. It is expected to be a valuable policy basis for efficient operation measures related to the kindergarten dietitians.

• Journal of the Korean Society of Food Culture
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• v.8 no.1
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• pp.55-62
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• 1993

These studies were conducted to: a) investigate work patterns and productivity indices, b) rate performance levels of employees and c) determine the suggested levels of personnel and labor hours for the effective labor control in school foodservice. Eighteen elementary school foodservices in Seoul were selected in order to analyze work patterns by the work sampling methodology. Allowance time and performance rating by VTR observation was done to determine the standardized labor hours. The results were as follows. The average percentage of each work function of the total work functions such as direct work function, indirect work function and delay were 65.57%, 8.12%, 26.31% respectively. The productivity index is 0.92 min/meal. The average working and delay hours per week of the foodservice director, foodservice employees and supply person were 33.64 hours, 23.25 hours, 38.52 hours respectively. The percentage of delay hours of total labor hours for foodservice employees and supply person were 42.27% and 24.0%. The standardized work hours and the appropriate levels of foodservice employees of 17 elementary school foodservices were examined: The average rating of the foodservice employees work was 1.19 and British Insulated Calendarer Cables (BICC) allowance rate was 19.40% on the average. The total work hours of foodservice employees were 172.64 hours per week and levels of personnel were 4.53 persons. BICC allowance rate was applied: The standardized work hours per week was 180.95 hours and appropriate levels of personnel were 4.11 persons based on legal 44 working hours.

• Journal of Fisheries and Marine Sciences Education
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• v.25 no.5
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• pp.1165-1178
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• 2013

The purpose of this study was to examine the current education issues in Korea by comparing instructional hours across countries. For accomplishing such purpose, a survey was conducted with 189 elementary schools, 94 middle schools and 42 high schools, 2010 OECD report was reviewed. Based on the research, the total number of instructional hours in elementary schools in Korea is around 610-710 hours, while the OECD average is around 760-810 hours, which is around 100-160 hours higher than that of Korea. In the case of middle schools, it is around 867 hours in Korea, while the OECD average is around 892 hours.

• Clinical and Experimental Reproductive Medicine
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• v.49 no.4
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• pp.270-276
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• 2022

Objective: The present study assessed the biological characteristics of human spermatozoa at different time intervals (0, 1, 1.5, and 2 hours) after incubation at 37℃. Methods: Twenty-five normozoospermic semen samples were incubated at 37℃. Incubation was performed at four time intervals of 0 (after liquefaction), 1, 1.5, and 2 hours. The samples were evaluated for sperm parameters at each time interval. Results: The rate of sperm progressive motility decreased at 1.5 hours compared to 0 hours as well as 2 hours compared to 1 hour and 0 hours. The rate of non-motile spermatozoa also decreased after 2 hours compared to after 0 hours. No significant changes were observed in sperm viability (p=0.98) and non- progressive motility (p=0.48) at any time intervals. Abnormal sperm morphology increased at 1.5 hours of incubation time (p<0.001). No significant changes were observed in DNA fragmentation at 1 hour compared to 0 hours (median [interquartile range]: 19.5 [4] vs. 19 [4]), as well as at 1.5 hours compared to 1 hour (20 [5]). However, a significant increase in DNA fragmentation was observed at 1.5 hours compared to 0 hours. The mitochondrial membrane potential decreased remarkably after 1 hour of incubation time. No significant differences were observed in the acrosome reaction or malonaldehyde levels at any time point (p=0.34 and p=0.98, respectively). Conclusion: The incubation of normozoospermic samples before use in assisted reproductive technology should be less than 1.5 hours to minimize the destructive effects of prolonged incubation time on general and specific sperm parameters.