• Journal of Korean Dental Hygiene Science
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• v.7 no.1
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• pp.39-52
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• 2024

Background: Dental hygienists provide direct dental care in the closest proximity to the patient, and each practice requires a high level of focus and concentration. These skills are an important human resource that can impact the quality of dental care services. Since more than half of dental clinics provide as overtime work in addition to regular hours, this study aims to determine the association between working overtime and job performance for dental hygienists. Methods: The study was conducted using a combination of online and in-person surveys via Google Forms among 131 employed dental hygienists. The survey consisted of 7 questions on demographic and work characteristics, 16 questions on characteristics related to overtime and the effect of overtime on job security, health, and life, and 10 questions on job performance, for a total of 33 questions. Chi-square analysis and independent samples t-test were used to identify the characteristics of demographic and work characteristics, and descriptive statistics analysis was used for the characteristics of overtime. Independent samples t-test was used to test the difference in the mean of job performance according to whether or not they worked overtime, and linear regression analysis was used to show the association of working overtime and job performance. Results: The study found that 71% of dental clinics worked overtime. The average number of overtime per week was once (78.5%), and the most common problems with overtime were fatigue (52.7%) and lack of personal and leisure time (41.9%). The appropriate number of overtime per week considered by dental hygienists was once a week, which was confirmed to be 94.6%. When comparing job performance by overtime status, those who worked overtime were 3.38 points higher than those who did not (35.45 vs. 32.07). Multiple linear regression analysis of the association of working overtime night and job performance showed that a one-unit increase in worked overtime was associated with a statistically significant increase in job performance of about 3.1 (p<0.01). Conclusion: Working overtime was found to have a positive effect on job performance among dental hygienists. Therefore, as a way to improve the working environment, providing appropriate compensation or welfare for overtime can reduce the negative aspects of overtime and turn it into a positive influence on job performance. This could ultimately raise awareness of the dental hygienist as a professional and effect the efficiency of dental care services.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.9 no.2
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• pp.227-236
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• 1998

Objectives：Conduct disorder is one of the most frequent diagnosis in outpatient and inpatient mental health facilities for children and adolescents. This study investigated the clinical characteristics of children and adolescents with conduct disorder. Methods：The study employed a retrospective review of 45 inpatients diagnosed with conduct disorder by DSM-IV criteria at SNUH Child Psychiatric Unit from 1993, March to 1998, September. Results：The results were as follows：1) The sex ratio was 2：1, male dominant. Mean age on admission was $12.8{\pm}2.4$ years old(male：$12.2{\pm}2.3$, female：$14.1{\pm}2.1$). The mean age of male subjects was significantly lower than that of female subjects(p<.05). 2) We classified all subjects according to child- or adolescent-onset type by DSM-Ⅳ. Childhoodonset type was 42.2%, and adolescent-onset, 57.8%. The onset of male subjects were significantly earlier than that of female subjects(p<.05). 3) The most common complaint was 'serious violation of rules'(77.8%) by DSM-Ⅳ dimensions, while the most common single symtom was 'run away from home overnight at least twice while living in parental or parental surrogate home'(48.9%). 4) The comorbid psychopathology of the subjects were frequently described as follows, in order of frequency：substance use(42.2%), ADHD(35.6%), depression(20.0%), tic disorder(11.1%), bipolar disorder(4.4%). 5) On MMPI, both Pd and Ma subscales got the highest scores. The mean of total IQ by KEDIWISC was $100.0{\pm}15.1$. Female subjects' IQ was higher than that of male subjects. 6) Regarding the number of visits to the OPD after discharge, many subjects(33.3%) had visited OPD fewer than four times. Conclusions：In this study, the male to female ratio of adolescent type showed a decreasing trend. An interesting finding was the fact that socio-economic circumstances, as well as the level of education among patients, were higher than those of previous studies. The subjects' problem were also principally self contered and posed no threat to others.

• Journal of Nutrition and Health
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• v.40 no.7
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• pp.606-615
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• 2007

This study was performed to investigate anti-thrombogenic, anti-inflammatory effects of n-BuOH (B) and $CH_2Cl_2$ (MC) fractions extracted from Sancho (Zanthoxylum. schinifolium) leaves in rats fed high fat diets. The experimental animal groups were consisted of eight including one 5% fat (N) and one 20% fat (H) without the test materials in diets and six H groups of feeding three levels (50, 100 and 150 mg/day) of the B and the MC fractions from Z. schinifolium, respectively. Plasma activated partial thromboplastin times and thrombin times of H group were decreased compared to the N group, but they were increased by feeding the MC fraction of 50 mg and over. Polymorphonuclear leukocyte 5#-lipo-xygenase activities and leukotriene $B_4$ contents of the H group were significantly increased compared to the N group, but they were decreased in the 100 mg and 150 mg of B fraction or the 150 mg of MC fraction fed groups. Liver cytochrome $P_{450}$, $O_2^-$, $H_2O_2$ and GSSG contents were increased by the high fat diet but decreased by feeding the B fraction or the MC fraction, while GSH content and glutathione S-transferase activity lowered by high fat diet were increased by feeding the two solvent fractions. The effects of the solvent fractions were evident at the level of 100 mg/day and over. The present results confirmed that two solvent fractions from the leaves of Z, schinifolium have enhancing effects on anti-thrombosis and anti-inflammation partly by antioxidant action and partly by direct modulation of the respective processeds. In conclusion, the n-BuOH and $CH_2Cl_2$ fractions from leaves of Z, schinifolium can be utilized as the proper ingredients of functional foods for preventing chronic degenerative disease.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.2
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• pp.109-118
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• 2012

This study achieves results from 22 maternity breast milk samples in total to demonstrate exposure level and risk assessment of PBDEs in Seoul area. PBDEs were detected in all the breast milk samples of the present study, indicating that general population in these Seoul area are widely exposed to these chemicals. Residue levels of total PBDEs (sum PBDEs from tri- to hepta-BDE) ranged of 0.84~13.1 ng/g lipid with an arithmetic mean and median of 3.56 ng/g lipid and 2.6 ng/g lipid, respectively. Global comparison shows that the levels of total PBDEs were relatively similar to those of China, Taiwan and European country (Sweden), and somewhat higher than those in some Asian (Vietnam, Philippines, and Indonesia). In the present study, however, the levels of total PBDEs in human milk are still one to two orders of magnitude lower than those in North America. Contribution rate of each congener appeared to be predominant with BDE-47, followed by BDE-153, BDE-100, BDE-99, BDE-154 and BDE-183. The sum of BDE-47 and BDE-153 accounted for more than 65% of total PBDEs in most samples. From the result of the human risk assessment of infants for total PBDEs and BDE-47 by breast milk feeding, we could find out that the average daily doses and hazard index (95th percentile) were 16.5 ng/kg bw/day and $1.2{\times}10^{-1}$ each other when nursing for 6 months after infants born. However, it was concluded that the infant health hardly had adverse seriously effects under this research condition.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.1
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• pp.46-55
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• 2017

In this study, extracts of gamma-irradiated Aralia continentalis for health and beauty food resources were examined on antioxidant activities and increasing extraction yield. In photostimulated luminescence analysis, non-irradiated (0 kGy) sample showed an intermediate result of 891.00 photon counts (PCs), whereas irradiated (5 and 10 kGy) samples showed positive results of 79,956.67 and 282,498.67 PCs, respectively. The thermoluminescence ratio of non-irradiated samples was 0.018, whereas the values of irradiated samples (5 and 10 kGy) were 0.395 and 0.464, respectively. Electron spin resonance (ESR) analysis as a physical technique for irradiation identification of Aralia continentalis showed a pair of peaks on a space of 6.0 mT in the symmetric ESR spectrums. For phenolics of gamma-irradiated Aralia continentalis, water extracts had the highest amounts of 7.61 mg/g at non-irradiated condition (0 kGy) while 50% ethanol extracts had the highest amounts of 6.86 mg/g at 10 kGy irradiation. 2,2-Diphenyl-1-picrylhydrazyl scavenging activity of water and 50% ethanol extracts from non-irradiated and irradiated Aralia continentalis were very high (94.99~100.00%). 2,2'-Azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical cation inhibitory activity was over 95.00% at $200{\mu}g/mL$ phenolics. Antioxidant protection factor (PF) showed a very high level of activity (1.38~2.51 PF). Thiobarbituric acid reactive substance inhibitory activity was high (70% and 95%, respectively). Thus, treatment of gamma irradiation can be used as a method of storage for long-term preservation of Oriental medicine.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.2
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• pp.82-89
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• 2014

Purpose: The purpose of this study was to observe the change of viscoelastic properties of dental resin cements during polymerization. Materials and methods: Six commercially available resin cement materials (Clearfil SA luting, Panavia F 2.0, Zirconite, Variolink N, RelyX Unicem clicker, RelyX U200) were investigated in this study. A dynamic oscillation-time sweep test was performed with AR1500 stress controlled rheometer at $32^{\circ}C$. The changes in shear storage modulus (G'), shear loss modulus (G"), loss tangent (tan ${\delta}$) and displacement were measured for twenty minutes and repeated three times for each material. The data were analyzed using one-way ANOVA and Tukey's post hoc test (${\alpha}$=0.05). Results: After mixing, all materials demonstrated an increase in G' with time, reaching the plateau in the end. RelyX U200 demonstrated the highest G' value, while RelyX Unicem (clicker type) and Variolink N demonstrated the lowest G' value at the end of experimental time. Tan ${\delta}$was maintained at some level and reached the zero at the starting point where G' began to increase. The tan ${\delta}$and displacement of the tested materials showed similar pattern in the graph within change of time. The displacement of all 6 materials approached to zero within 6 minutes. Conclusion: Compared to other resin cements used in this study, RelyX U200 maintained plastic property for a longer period of time. When it completed the curing process, RelyX U200 had the highest stiffness. It is convenient for clinicians to cement multiple units of dental prostheses simultaneously.

• Journal of Nutrition and Health
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• v.41 no.8
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• pp.851-859
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• 2008

To promote the adoption of healthier eating patterns, this study was aimed to develop and evaluate alternative front of pack nutrition signposting concepts. Based on previous research, we developed two signposting concepts, Multiple Traffic Light (MTL) and Multiple Traffic Light with % Daily Value (MTL-%DV). The signposts featured three key nutrients, total sugar, saturated fat, and sodium. Actual food packaging with no front of pack signposting (NoSP) was included in the evaluation to act as a benchmark against which to compare the performance of the different signposting options. Using an interviewer administered method, we assessed the degree of understanding and time to interpret on a total of 534 subjects (194 elementary, 108 middle, and 103 high schoolers, 128 adults). In the individual product evaluations, MTL (87.0%) obtained the highest level of correct responses, followed by MTL-%DV (83.1%) and NoSP (52.2%). Except for signposting concepts, age, gender and living area were not associated with the degree of correct responses in multivariate analyses. When used to compare products with different colors of nutrient contents, correct responses were more than 90% for MTL-%DV (91.5%) and MTL (90.3%). The middle and high schoolers revealed the lower likelihood of correct response compared to the other two groups. In case of comparing products with same colors of nutrient contents, the proportion of correct responses was the highest in NoSP (90%), followed by MTL%DV (77.4%) and MTL (48.5%). In terms of time to interpret, MTL-%DV and MTL performed better than NoSP in the individual product evaluation and the comparison of two products with different colors of nutrient contents. NoSP performed the best in the comparison of two products with same colors of nutrient contents. A majority of the participants preferred MTL-%DV (78%) most and thought it the most useful in helping them make healthier food choices. Based on these findings, MTL-%DV was considered to most closely meet the objectives of the initiatives.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.1
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• pp.38-46
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• 2002

Chrysanthemum boreale M. (hereafter, C. boreale M.), a perennial flower, has been historically used as a natural medicine in Korea. With increasing concerns for health-improving foods, the demand for C. boreale M. has become higher than ever. Howevr, the amount of wild C. boreale M. collected from mountainous areas is not enough to cover all demands. The cultivation system and fertilization strategy are required to meet increasing demand on C. boreale M. with a good quality. We investigated the effects of nitrogen application on plant growth and effective components of C. boreale M. to suggest optimum rate of nitrogen fertilization. C. boreale M. was cultivated in a pot scale (1/2000a scale), and nitrogen applied with rate of 0(N0), 50(N50), 100(N100), 150(N150), 200(N200), and $250(N250)kg\;ha^{-1}$. Phosphate and potassium were applied at the same level ($P_2O_5-K_2O=80-80kg\;ha^{-1}$) in all treatments. Maximum yield achieved in 246 and $226kg\;ha^{-1}$ N treatment on the whole plant and the flower part, a valuable part as a herbal medicine, respectively. Proline was the most abundant amino acid in the flower of C boreal M. and the contents of amino acids increased with increasing nitrogen application rate in flower. Nitrogen recovery efficiency was high more than 41% in all nitrogen treatments and increased to 61.8% in nitrogen N100 treatment. From the nitrogen content, the high nitrogen uptake, the low residue of mineral N and the reasonably good apparent fertilizer recovery, it can be inferred that C. boreale M. made efficient use of the available nitrogen. In flower, contents of Cumambrin A. which is a sesquiterpene compound and has the effect of blood-pressure reduction, decreased with increasing nitrogen application. However, the amount of Cumambrin A in flower increased as nitrogen rate increased, because of increasing flower yield. Conclusively, nitrogen fertilization could increase yields and enhance quality. The optimum nitrogen application rate might be on the range of $225{\sim}250kg\;ha^{-1}$ in a mountainous soil.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.1
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• pp.71-81
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• 2005

The purposes of this study was to collect, analyze, and describe the MF exposure levels from subways in Korea and to measure and evaluate the MF levels generated from electric appliances used at general homes. The target subway lines were Seoul Metropolitan Line 1 to Line 8, Bundang Line, Incheon Line, Daegu Line, Gwangju Line, and Busan Line 1 and Line 2. We measured at each station in those subway lines and, all the train types (pantograph-equipped, motor-equipped, and common), and platform types(facing and isolating) were investigated by the distance(80, 200, 400 cm) from the train on 19 targeted subway lines using 3 magnetic field measuring devices (EMDEXII, Enertech Co.) during the survey from January till October, 2004. On the other hand, the levels of the 60Hz magnetic fields generated from 14 items of home electric appliances such as electric blankets, hair dryers, electric razors, etc. were measured at 10 general homes using 5 EMDEXII meters with a sampling interval of 1.5 second by the distance(surface, 30, 50, 100, 300cm ) from the target electric appliances. The survey results in the whole subway lines examined in this study were as follows; Seoul Metropolitan Line 4 using AC(alternating current) power source showed the highest mean value of $2.85{\mu}T$, followed by Seoul Metropolitan Line 1 running between Seoul and Incheon using AC($2.78{\mu}T$), Seoul Metropolitan Line 1 between Seoul and Uijongbu using AC($2.73{\mu}T$), Bundang Line using AC($1.79{\mu}T$), Seoul Metropolitan Line 1 connected from Yongsan using AC($1.67{\mu}T$), Seoul Metropolitan Line 1 between Seoul and Suwon using AC($0.79{\mu}T$), and so on. In general, the intensity of the magnetic field in the subway systems in Korea was significantly higher when using AC($2.14{\pm}0.91{\mu}T$) than when using DC($0.29{\pm}0.44{\mu}T$) power source. Among the home electric appliances examined, microwave ovens showed the highest mean value of $7.69{\mu}T$, followed by hair dryers($6.47{\mu}T$), vacuum cleaners($5.27{\mu}T$), televisions ($2.26{\mu}T$), electric blankets($1.38{\mu}T$), personal computers ($0.81{\mu}T$), and so on. Two items of electric appliances showed the excess value of $0.2{\mu}T$ at the distance of 30cm in the MF exposure level; electric razors $1.58{\pm}2.13{\mu}T$ and vacuum cleaners $0.48{\pm}0.44{\mu}T$. As a whole, this study showed a tendency that the shift of the MF levels according to the increase of distance from the electric appliances was lower than those of the results surveyed in UK and USA. As a result, this study is expected to suggest meaningful data for the future study in exposure assessment of magnetic fields and for the establishment of guidelines for subways and electric appliances in Korea. More detailed and large scaled exposure assessment studies should be performed continuously to get the various and useful information on health risk assessment of MFs in Korea.

• The Korean Journal of Food And Nutrition
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• v.29 no.5
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• pp.767-776
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• 2016

The aim of this study was to evaluate key properties of the prickly pear cactus (Opuntia ficus-indica var. saboten (OFI) ie, levels of key chemicals (carotenoids, flavonoids and polyphenolic compounds as well as phenolic acid) and its antioxidative potential, depending on where the plant had been cultivated in Korea. The levels of flavonoids and polyphenolic compounds in OFI were 55.45~65.32 mg (+)-catechin/g and 149.00~181.15 mg gallic acid/g, respectively. Protocatechuic acid was the most abundant phenolic acid in the ON1 and ON2 (161.90 and $196.25{\mu}g/g$ DW (dry weight)). Nineteen flavonoids were identified and analyzed by LC-ESI-MS in cladodes from OFI. Narcissin was the most abundant flavonoid in all of the samples ($1,241.89{\sim}1,775.10{\mu}g/g$ DW). Capxanthin and zeaxanthin were the most abundant carotenoids in OFI (64.88~128.08 and $48.10{\sim}93.82{\mu}g/g$ DW). The level of DPPH radical and ABTS radical scavenging activities in OFI were 10.78~25.35 and 16.85~34.16 mg AA eq/100 g, respectively. OFI by cultivar has different kind of phenolic acid, flavonoids, and carotenoids. Therefore, dietary intake of cladodes from OFI may be helpful for improving human health.