• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.26 no.2
• /
• pp.110-123
• /
• 2021

We investigated geochemical constituents of pore-water and sediment, rates of organic carbon (C_org) oxidation and sulfate reduction (SR), and benthic nutrient flux (BNF) to elucidate characteristic of C_org oxidation and its control in the coastal area near Lake Shihwa. The study sites were selected in the vicinity of Soraepogu (E0), Songdo tidalflat (E1) and Oido dock (E3) and in front of floodgate Shihwa tidal plant (E5). The C_org contents in the sediments and concentrations of ammonium and phosphate in pore water exhibited the highest value at EO, and gradually decreased toward the outer sea (E1, E3, E5). Rates of anaerobic C_org oxidation (260.6 mmol C m^-2 d^-1) and SR (91.4 mmol S m^-2 d^-1) at E0 were 4-9 and 6-54 times higher than at the site of outer sea (E1, E3, E5). Rates of SR at E3 and E5 accounted for 11-23% of anaerobic C_org oxidation, whereas it comprised 47-70% of anaerobic C_org oxidation at E0 and E1. Rates of C_org oxidation and SR showed a highly positive correlation with the concentration of dissolved organic carbon (r² = 0.795 and 0.777, respectively). The BNF at E0, E1, and E3 accounted for 120-510% and 26-178%, respectively, of the N and P required for primary production in the water column. Overall results suggest that the C_org oxidation in the sediment controlled by concentration of dissolved organic carbon in the pore water and the excessive C_org oxidation stimulates the benthic nutrient flux, which may cause a phytoplankton bloom in the water column.

• Journal of Korea Entertainment Industry Association
• /
• v.14 no.4
• /
• pp.321-331
• /
• 2020

This study was conducted to investigate communication competence, clinical competence and experience of handover which influence self-efficacy of handover among nursing students. The study design was a descriptive survey. A total of 255 students were recruited from nursing departments in G-city. Structured questionnaire was self-administrated from June to September, 2019. The collected data were analyzed using t-test, ANOVA, Pearson's coefficient and stepwise multiple regression. As results of the study, communication competence 57.3, clinical competence 69.8 and self-efficacy of handover was 33.8. Self-efficacy of handover had significant differences in gender(F=4.60, p<.001), age(F=16.72, p<.001), grade(t=-6.39, p<.001), satisfaction of clinical practice(F=3.68, p=.027), education experience about handover(t=26.44, p<.001), experience of handover(t=4.84, p<.001), fear of handover(F=16.97, p<.001), and handover importance of patient's safety(F=6.42, p=.002). Self-efficacy of handover had significant positive correlations with communication competence(r=.249, p<.001) and clinical competence(r=.426, p<.001). In multiple regression analysis, fear of handover(β=-.294, p<.001), clinical competence(β=.252, p<.001), grade(β=.191, p=.001), experience of handover(β=.185, p<.001), gender(β=.150, p=.003), and education experience about handover(β=.126, p=.017) were significant factors of self-efficacy of handover explaining 40.0%(F=29.26, p<.001) of the variables. In conclusion, to enhance self-efficacy of handover for nursing students, it is necessary to develop educational program for increasing experiences of handover, education experience about handover, and clinical competence.

• Korean Journal of Psychosomatic Medicine
• /
• v.29 no.2
• /
• pp.111-120
• /
• 2021

Objectives : Shift work has been known to cause various health problems by making it difficult for humans to adapt to their natural circadian rhythms. In particular, shift workers tend to complain of sleep difficulties associated with work schedules, and sometimes use alcohol as a self-medication to induce sleep. To date, no clear mechanism has been identified regarding the link between shift work and sleep, between shift work and drinking. This study aims to confirm the relationship between shift work and sleep, and to analyze whether the change in sleep caused by shift work causes drinking. Methods : This study included 11360 people (5704 men and 5656 women) among the Korean National Health and Nutrition Survey data in 2014, 2016 and 2018. The work type between 6am-6pm was defined as day work, and other work types were defined as shift work. Using logistic regression analysis, the relationship between shift work and sleep quality, shift work and high risk drinking, drinking amount at 1 time, drinking frequency were analyzed. In addition, we analyzed whether sleep mediates the relationship between shift work and drinking using mediated analysis. Results : Shift work showed a significant negative relationship with sleep quality in men and women (male OR=1.37, 95% CI 1.11-1.70, female OR=1.26, 95% CI=1.05-1.50). There was no significant relationship between shift work and alcohol in the case of men, but in the case of women, there was a significant positive relationship between shift work and the number of alcohol consumption (OR=1.34, 95% CI=1.04-1.72). When mediation analysis was conducted, it was found that women's sleep quality partially mediated the relationship between shift work and the frequency of drinking. Conclusions : The results of this study suggest that shift work causes sleep difficulties, and in the case of women, drinking can be induced through the partial mediating effect of sleep. Considering that women are more likely to choose drinking as a coping method for sleep problems, more active interventions for female shift workers are needed.

• Journal of the Microelectronics and Packaging Society
• /
• v.28 no.4
• /
• pp.11-18
• /
• 2021

A novel microwave dielectric composite material for ultra-low temperature co-fired ceramics (ULTCC) with (1-x)BaWO₄-xBaV₂O₆ (x=0.54~0.85) composition was prepared by firing a mixture of BaWO₄ and BaV₂O₆. Shrinkage tests showed that the ceramic composite begins to densify at a temperature as low as 550℃ and can be sintered at 650℃ with 98% of relative density under the influence of BaV₂O₆. X-ray diffraction analysis showed that BaWO₄ and BaV₂O₆ coexisted and no secondary phase was detected in the sintered bodies, implying good chemical compatibility between the two phases. Near-zero temperature coefficients of the resonant frequency (𝛕_f) could be achieved by controlling the relative content of the two phases, due to their positive and negative 𝛕_f values, respectively. With increasing BaV₂O₆ (x from 0.53 to 0.85), the 𝛕_f value of the composites increased from -7.54 to 14.49 ppm/℃, ε_r increased from 10.08 to 11.17 and the quality factor (Q×f value) decreased from 47,661 to 37,131 GHz. The best microwave dielectric properties were obtained for x=0.6 samples with ε_r=10.4, Q×f=44,090 GHz, and 𝛕_f=-2.38 ppm/℃. Chemical compatibility experiments showed the developed composites are compatible with aluminum electrode during co-firing process.

• Journal of Korean Home Economics Education Association
• /
• v.33 no.4
• /
• pp.49-64
• /
• 2021

Apprenticeship education in Korea started approximately in 2005, and is divided into government-led apprenticeship education and Gyeonggi-do-led apprenticeship education. Apprenticeship education for textile and clothing-related majors in Korea is a very different process compared to Germany, where the country, companies, and schools have cooperated with each other with a long tradition, and there are many points to be supplemented. In order to explore the literature on apprenticeship education in Germany and Korea, and to understand the phenomena or actual conditions that have not been shown in the literature, interviews were conducted with two German professors living in South Korea. As a result of the analysis, Germany's long tradition and positive perception of vocational education are the basis for the establishment of apprenticeship education, and it is positioned as a system of education process. Various associations related to apprenticeship education make systematic training manuals, and then distribute certificates to trainees who have completed these courses. Therefore, companies promote the stability of the job market by educating local talents through apprenticeship training to nurture industrial manpower. Currently, in Korea's apprenticeship education, a series of procedures for developing educational courses such as company discovery and job analysis for each company are entirely entrusted to vocational high schools. Therefore, public confidence and solidity in apprenticeship education were found to be insignificant. This study has limitations in that it cannot confirm a phenomenon that has not been shown in the literature review, there is insufficient research on German literature, and the number of samples interviewed is small. However, if, based on the results of this study, an association dedicated to apprenticeship education is created in Korea and a systematic curriculum is developed, it will be able to contribute to establishing the stability of the textile and apparel labor market in the future.

• Korean Journal of Psychosomatic Medicine
• /
• v.30 no.2
• /
• pp.119-126
• /
• 2022

Objectives : The purpose of this study was to examine the clinical utility of the internalization and externalization higher-order scales of the Minnesota Multiphasic Personality Inventory-Adolescent Restructured Form (MMPI-A-RF), compared with those scales of the Korean Child Behavior Checklist (K-CBCL). Methods : 43 adolescents with internalizing disorders and 44 adolescents with externalizing disorders and their parents were administered the MMPI-A-RF and K-CBCL each. To verify the difference between the internalization and externalization scales of the MMPI-A-RF and K-CBCL for each group, independent-sample t test was performed. To compare the agreement between the MMPI-A-RF and K-CBCL, correlation analysis was also conducted. Lastly, to identify which scales significantly best predict each of the internalizing and externalizing disorder, logistic regression analysis was conducted. Results : Internalization scales of the MMPI-A-RF and K-CBCL were significantly higher in the internalizing disorder group, and the externalization scales were significantly higher in the externalizing disorder group. The positive correlation was significant only for internalization problems between the two evaluation measures in both groups (each r=0.360, p<0.05, r=0.572, p<0.05). In addition, the scales significantly predicted internalizing and externalizing disorders were the internalization and externalization scales of the MMPI-A-RF, followed by the externalization scale of the K-CBCL (R²=0.407, p<0.05). Conclusions : The internalization and externalization higher-order scales of the MMPI-A-RF were found to reliably reflect the characteristics of each disorder in adolescents and be useful evaluative scales to differentiate disorders. Moreover, if adolescents show externalization problems, additional information from the K-CBCL can be more useful to differentiate disorders.

• Korean Journal of Psychosomatic Medicine
• /
• v.30 no.2
• /
• pp.155-164
• /
• 2022

Objectives : A growing body of evidence links type 2 diabetes (T2D) with a neurodegenerative disease (ND) such as Alzheimer's disease and Parkinson's disease. The purpose of this study is to investigate the relationship between NDs and the development of T2D by comparing the incidence of T2D in a group of various NDs (ND group) and control group. Methods : A population-based 10-year follow-up study was conducted using the Korean National Health Information Database for 2002-2015. We used a retrospective cohort study design to investigate the association of ND with T2D occurrence. The study population included ND (n=8,814) and control (n=37,970) groups, all aged 60 years or over. The Kaplan-Meier method was used to estimate the risk of developing T2D as a function of time. Cox proportional hazards regression models were used to evaluate the relationship between ND and T2D. Results : T2D was developed in a significantly higher percentage of patients in the ND group (53.6%) than in the control group (44.7%). The ND group increased the risk of T2D (HR, 1.43; 95% CI, 1.38-1.47). About one-third of patients in both groups were additionally diagnosed with another ND before the occurrence of T2D during a 10-year follow-up period. When compared to those who did not have another ND during the follow-up period, the incidence of T2D in those who were additionally diagnosed with another ND was higher in both the ND and control groups. Conclusions : The ND group had about 1.4 times higher risk of developing T2D than the control group. Our results showed a positive association between ND and T2D.

• Journal of Marine Life Science
• /
• v.7 no.2
• /
• pp.196-204
• /
• 2022

This study observed changes in survival, growth performance and water quality for 90 days to confirm the possibility of Leiocassis ussuriensis farming using Biofloc technology (BFT) using Bacillus subtilis. Feed and molasses were added to the experimental tank to produce BFT water before planting the experiment, and B. subtilis was inoculated to stabilize the water quality for 40 days. The survival rate of the experimental fish was 92.7±3.2% in the control group and 95.8±3.3% in the BFT group. The Weight gain (WG) was 118.1±9.0% of the control and 197.7±15.6% of the BFT, and the Specific growth rate (SGR) was 0.87±0.5% of the control and 1.21±0.06% of the BFT. As for the feed efficiency, the control was 43.7±2.6% and the BFT was measured at 70.1±4.1%, indicating that the feed efficiency of the BFT was higher. As a result of measuring the water quality change during the experimental period, pH was reduced in both the control and the BFT, and Mixed Liquor Suspended Solids (MLSS) did not show any change in the control, but the BFT showed a significant increase at 90 days. NH₄⁺-N and NO₂^--N showed a significant increase from the 30 days of the experiment in the control, but showed no change in the BFT. In conclusion, as a result of applying the BFT system using B. subtilis to the process of cultivating Leiocassis ussuriensis, the water quality tended to stabilize, and the growth rate and feed efficiency were found to be higher than those of the control, confirmiWng that it had a positive effect.

• Korean Journal of Poultry Science
• /
• v.49 no.4
• /
• pp.287-298
• /
• 2022

This study evaluated the efficacy of chlorine dioxide (ClO₂) as an oxidant to reduce malodor emission from chicken feces. Two experiments were performed with the following four treatments in parallel: 1) fresh chicken feces with only distilled water added as a control, 2) a commercial germicide as a positive control, and 3) 2,000 or 4) 3,000 ppm of ClO₂ supplementation. Aluminum gas bags containing chicken feces sealed with a silicone plug were used in both experiments, and each treatment was tested in triplicate. In Experiment 1, 10 mL of each additive was added on the first day of incubation, and malodor emissions were then assessed after 10 days of incubation. In Experiment 2, 1 mL of each additive was added daily during a 14-day incubation period. At the end of the incubation, gas production, malodor-causing substances (H₂S and NH₃ gases), dry matter, pH, volatile fatty acids (VFAs), and microbial enumeration were analyzed. Supplementing ClO₂ at 2,000 and 3,000 ppm significantly reduced the pH and the ammonia-N, total VFA, H₂S, and ammonia gas concentrations in chicken feces compared with the control feces (P<0.05). Additionally, microbial analysis indicated that the number of coliform bacteria was decrease after ClO₂ treatment (P<0.05). In conclusion, ClO₂ at 2,000 and 3,000 ppm was effective at reducing malodor emission from chicken feces. However, further studies are warranted to examine the effects of ClO₂ at various concentrations and the effects on malodor emission from a poultry farm.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.49 no.3
• /
• pp.300-309
• /
• 2022

This study aimed to evaluate the effects of two ginsenoside Rb1 (G-Rb1) loaded films on oral wound healing. Two types of G-Rb1 films, G-Rb1 loaded carboxymethyl cellulose (GCMC) film and G-Rb1 loaded hyaluronic acid (GHA) film, were developed. A total of 36 Sprague-Dawley rats were divided into 3 groups: control, GCMC, and GHA. After wound formation on midpalate, the control group was left without treatment, whereas the experimental groups had films attached. The specimen was analyzed clinically and histologically after 7 and 21 days. For clinical analysis, the area of incompletely re-epithelialized wound was measured. For histological analysis, the distance between the margins of the wound (soft tissue gap) was measured and the percentage of the collagen-stained area on the specimen was calculated. In clinical and soft tissue gap analysis, the GCMC group presented improved healing compared to the GHA group and the control at day 7 (p < 0.05). And, both GCMC (9.74 ± 10.12%) and GHA groups (19.50 ± 14.47%) presented greater collagen-positive pixels compared to control (0.89 ± 1.60%) at day 7 (p < 0.05). However, there were no differences in these parameters among the groups on day 21. Therefore, G-Rb1 loaded films improved oral wound healing.