• Journal of Dental Rehabilitation and Applied Science
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• v.38 no.1
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• pp.18-25
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• 2022

Purpose: This study aimed to evaluate the color stability and antibacterial properties of the surface of polyethyl methacrylate (PEMA) resin with zirconia nanoparticles added. Materials and Methods: The control group was pure PEMA resin, and the experiment group was PEMA resin 15 mm in diameter and 2.5 mm in thickness disk-shaped specimens with 2, 4 and 8 w/v% of zirconia nanoparticles added, which were respectively divided into Group Z2, Group Z4, and Group Z8. After analyzing the surface roughness and color stability of the specimens, their antibacterial properties were evaluated using Porphyromonas gingivalis (P. gingivalis). The Statistical analysis was performed using when normality was met in the Shapiro-Wilk test, one-way ANOVA was used to test parameters, and Tukey's test was used as a post hoc test. When normality was not met, the Kruskal-Wallis test, a non-parametric test was used (P < 0.05). Results: The surface roughness measurement found that there was no significant difference between the experimental and control groups. The color stability evaluation showed that the Z2, Z4, and Z8 groups were within the color range of natural teeth. The adhesion of P. gingivalis was evaluated to be significantly reduced in Group Z2 compared to the control group (P < 0.05). In the Z2 group, Z4 group, and Z8 group, dead cells bacteria than the control group were observed. Conclusion: In conclusion, PEMA resin with zirconia nanoparticles added was within the range of natural teeth in color and reduced the adhesion of P. gingivalis.

• Journal of the Korean Society of Floral Art and Design
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• no.41
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• pp.3-12
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• 2019

The purpose of this study was to investigate the effect of forest play activities on children's emotional vocabulary change. Forest play activities were conducted for 498 children aged 4 to 5 years old who visited the environmental training in G city for forest play activity for 1 hour. As a result, positive vocabulary was significantly improved from 0.95±0.78 before forest play to 1.15±1.21 after forest play(p=.003) and negative vocabulary was significantly decreased from 1.27±1.58 to 0.41±1.10(p=.000). In the case of male children, positive vocabulary was increased significantly from 0.96±0.82 to 1.36±1.24(p=.000), in the case of negative vocabulary, it decreased significantly from 1.42±1.74 to 0.55±1.30(p=.000). In the case of female children, negative vocabulary was significantly decreased from 1.12±1.37 to 0.26±0.26(p=.000), but the positive vocabulary increase was not significant(p=.851). As a result of age, for a 4-year-old children, positive vocabulary did not show significant difference between before and after forest play(p=.471), and negative vocabulary was significantly increased from 1.04 ± 1.42 before forest play to 0.41±1.16 after forest play(p=.000). For a 5-year-old children, positive vocabulary was increased significantly from 0.96±0.85 to 1.23±1.21(p=.001) and negative vocabulary was decreased significantly from 1.41±1.65 to 0.41±1.06(p=.000). As a result of this study, it was found that play activities using various natural objects in the forest were directly related to nature, resulting in positive vocabulary increase and negative vocabulary decrease.

• Economic and Environmental Geology
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• v.56 no.3
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• pp.301-310
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• 2023

Ferrihydrite is an iron oxide mineral that is easily found in the natural environment, including acid mine drainage, and has a low crystallinity and high specific surface area, resulting in high reactivity with other ions, and can remove environmentally hazardous substances. However, because ferrihydrite is a metastable mineral, there is a possibility of releasing adsorbed ions by phase transformation to other minerals having low surface area and high crystallinity. In this study, the adsorption characteristics of arsenate, chromate, and selenate on ferrihydrite and the oxyanion removal efficiency of ferrihydrite were studied considering mineral phase transformation. At both pH 4 and 8, the adsorption of oxyanions used in the study were in good agreement with both Langmuir and Freundlich adsorption models except for selenate at pH 8. Due to the difference in surface charge according to pH, at pH 4 a higher amount of ions were adsorbed than at pH 8. The adsorption amount were in the order of arsenate, chromate, and selenate. These different adsorption models and adsorption amounts were due to different adsorption mechanisms for each oxyanions on the surface of ferrihydrite. These adsorption characteristics were closely related to changes in the mineral phase. At pH 4, a phase transformation to goethite or hematite was observed, but only a phase transformation to hematite was observed at pH 8. Among the oxyanion species on ferrihydrite, arsenate showed the highest adsorption capacity and hardly caused phase transformation during the experimental period after adsorption. Contrary to this, chromate and selenate showed faster mineral phase transformation than arsenate, and selenate had the lowest retardation effect among the three oxyanions. Ferrihydrite can effectively remove arsenate due to its high adsorption capacity and low phase transformation rate. However, the removal efficiency for other two oxyanions were low by the low adsorption amount and additional mineral phase transformation. For chromate, the efficient removal is expected only at low concentrations in low pH environments.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.1
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• pp.68-76
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• 1996

To elucidate the optimum fertilizer level and application method for band application under puddled-soil drill seeding in Jeonbuk series of fluvio-marine alluvial soil at National Honam Agricultural Experiment Station in 1995, using Dongjinbyeo, slow releasing compound fertilizer of 100％ and 80％ to conventional application level was applied totally as basal fertilizer simultaneously with seeding under 3cm and 5cm depth from soil surface in a distance of 4cm from the seeded row. Plant height was taller and tiller number was higher in band application than conventional application but ratio of effective tiller was vice versa. Panicle number was more but ratio of effective tiller ratio was lower in 100％ than 80％ level of band application and they were higher in 3cm than 5cm depth from soil surface. Leaf area index and dry weight was higher in conventional application at early growth stage but was vice versa after maximum tillering stage, and they were higher in 3cm depth at early growth stage but 5cm depth after maximum tillering stage. NH$_4$-N in soil was higher in conventional application at 25 days after seeding but, thereafter was lower than band application and it was higher in 3cm than 5cm depth till 40 days after seeding but was versa, thereafter. Lodging degree was slightly higher in band application, 100％ level and 5cm depth than in their counterparts. Panicle number and grain number per $m^2$ was lower in conventional application than 80％ or 100％ level of band application without significant difference between band application levels or application methods. Yield was higher at 80％ level of band application under 3cm depth than conventional application, but no significantly different among other application methods. Therefore, 80％ level of band application under 3cm depth of soil surface was more effective for puddled-soil drill seeding on the basis of the reduction of application efforts, better plant growth and higher yield in rice.

• 한국노년학
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• v.29 no.4
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• pp.1539-1557
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• 2009

The purpose of this study was to analyze the effects of program's participation, self-esteem and depression on quality of life for the elderly participating social welfare using facilities. Therefore, this paper will help improve a life's quality of all the olds by fixing the problems we got in this society and suggesting the better program for the elderly participating social welfare using facilities. The results of the study were as follows. There was no specific difference in statistic that shows the quality of the old's life who have their economic life. In quality of life in neighbors, the male were more friendly to their neighbors and the lower level of education, the higher quality of life. Healthy old people had greater quality of life than unhealthy old people did. If the old were excellent in scholarship, if unmarried couple shared the same house, if both of husband and wife live together when they are married, and if their allowance are full in pocket, the quality of their life was enhanced. Self-esteem influenced the quality of life in economic, but depression influenced negatively. In quality of life in neighbors, feeling depression and joining in program of a work for prosperity in future didn't effect doing well with the neighbors. On the other hand, participating in the social community program effected positively. In quality of life in neighbors, feeling depression and program of rehabilitation effected on the quality of life negatively. Educating refinement program effected positively being a good match, but promoting health program effected negatively.

• 한국노년학
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• v.39 no.1
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• pp.127-144
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• 2019

The purpose of this study is to compare the perceptions of loneliness, death anxiety, and social capital among older adults living in urban and rural communities and to examine the moderating effects of social capital on the relationship between loneliness and death anxiety. Utilizing the survey data collected by the Aging Society and Social Capital Research Center in 2018, we analyzed 839 older adults living in urban areas and 322 rural older adults living in rural areas. We used descriptive statistics, results from t-tests, and χ² tests to compare the rates of loneliness, social capital, and death anxiety perceived by older adults across urban and rural areas. The moderating effects of social capital on the relationship between loneliness and death anxiety were tested by logistic regression analyses for each group of urban and rural older adults. Compared to older adults living in rural areas, a greater number of older adults in urban areas reported death anxiety and higher levels of loneliness. However, the perceived levels of social capital were higher among rural older adults. The moderating effects of social capital on the relationship between loneliness and death anxiety were not found among older adults living in urban area, but, for older adults living in rural areas, social capital including social cohesion and social support moderated the relationship between loneliness and death anxiety. The results of this study suggest that regional differences shown in the perceptions of loneliness, death anxiety, and social capital should be addressed, when considering extensions of social capital and related interventions to deal with loneliness and death anxiety among older adults.

• Korean Journal of Culture and Social Issue
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• v.16 no.3
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• pp.355-383
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• 2010

In this study, the effects of skill-utilization based underemployment on self-esteem and mental health were examined. Also the moderating effects of employment commitment and social support were verified. Data obtained by a longitudinally designed survey with the reemployed (N=153) after job loss were used. The skill-utilization based underemployment was measured in two ways. One is measured in the way that use objective data, the ratio of education - 'educational requirement for the current job' divided by 'individual educational attainment.' The other is measured in the way that use psychological and self-reported measure, two factors of overqualification - the absence of opportunity for growth (no-growth) and the occupational mismatch in educational attainment, skills and experiences (mismatch). The main effect revealed that the no-growth made self-esteem lower and mental health (GHQ-social maladjustment) worse. The significant interaction of the ratio of education and employment commitment indicates that the negative effects of underemployment measured by the ratio of education on mental health (GHQ-social maladjustment, GHQ-depression/anxiety) were greater for those perceiving low employment commitment than for those perceiving high employment commitment. The significant interaction of the ratio of education and social support indicates that the negative effects of underemployment measured by the ratio of education on mental health (GHQ-depression/anxiety) were greater for those perceiving low social support than for those perceiving high social support. The two moderators also interacted with the two factors of perceived overqualification. Employment commitment had significant interaction effects with the no-growth and the mismatch on self-esteem and mental health (GHQ-depression/anxiety), whereas social support had a significant interaction only with the no-growth on mental health (GHQ-depression/anxiety). The significant interactions show that employment commitment and social support function as buffers in reducing the negative effects of skill-utilization based underemployment on self-esteem and mental health.

• Korean Journal of Poultry Science
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• v.50 no.3
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• pp.125-132
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• 2023

This study was conducted to investigate the effect of moisture absorbent (MA) application timing for litter management on broiler performance, blood cell characteristics, litter moisture content, incidence of footpad dermatitis (FPD), and economics analysis. Treatment include untreated control (NC), 3-week-old litter treatment (PC), 0-week-old (W1), 0 and 3-week-old (W2), 3-week-old (W3) application of moisture absorbent. Six hundred eighty broilers (1-day-old, 42.0±0.24 g) were divided into 5 treatments (4 replications per treatment, 34 birds per replication) and raised for 5 weeks in a floor (2 m² per pen). There was no significant difference among treatments in performance, blood cell characteristics, and H/L ratio according to the application period of litter and moisture absorbent. The litter moisture content and the FPD score were significantly decreased in the litter and moisture absorbent treatments at the age of 5 weeks (P<0.05). The FPD score of broilers was lowest in PC treatment compared to NC treatment (P<0.05). The incidence of FPD was lower in PC and W3 treatments compared to other treatments, and that was the highest in NC treatment. As a result of analyzing the economic feasibility, the highest expenditure occurred in PC treatment, and the lowest expenditure occurred in W3 treatment. Income was the highest in W3 treatment, and lowest in NC treatment. The profit was 185,859 won (1,367 won/unit), the highest in the W3 treatment. In conclusion, when MA was applied to the litter of broiler house at the age of 3 weeks, the litter moisture content and FPD were improved.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.3
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• pp.167-174
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• 2023

This study investigated the microstructure and water absorption characteristics of the Korean adzuki bean (Vigna angularis L.) cultivar under accelerated storage. The germination rate, acid value, redness (a^*), and yellowness (b^*) values showed no significant differences after three months of storage compared to pre-storage under low temperatures (4℃). However, a statistically significant difference was observed under accelerated high temperatures (45℃). In particular, after storage for three months, the germination rate and acid value were 0% and 33.63 mg KOH/100g, respectively, under accelerated high temperatures. After storage for three months, the holes, hilum damage, and spaces between the seed coat and cotyledon shortened the time and speed of water absorption under accelerated high temperatures compared to that under low temperatures. Conversely, further research is required to investigate the reason for the low rate of parallel water absorption.

• Journal of Life Science
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• v.33 no.12
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• pp.1052-1061
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• 2023

This study was carried out to evaluate the effect of fermentation by B. subtilis (BPLE), L. brevis (LPLE), S. cerevisiae (SPLE) and C. militaris (CPLE) on the antioxidant activity of Protaetia brevitarsis larvae fed with mushroom substrates (king oyster mushroom). The total polyphenol content of Protaetia brevitarsis larvae (PLE), BPLE, LPLE, SPLE and CPLE were 58.07±0.67, 83.33±0.98, 79.21±1.32, 61.02±0.87 and 57.90±1.02 mg GAEs/extract g, respectively. The flavonoid contents of the PLE, BPLE, LPLE, SPLE and CPLE were 17.35±1.57, 19.49±0.95, 16.90±1.57, 18.12±0.95 and 16.99±0.95 mg QEs/extract g, respectively. The DPPH radical scavenging activity showed no significant difference between the PLE, BPLE, LPLE, SPLE and CPLE at a concentration of 0.2 mg/ml. However, at a concentration of 0.4 mg/ml or more, the DPPH radical scavenging activity of the BPLE and LPLE was higher than that of the PLE. The reducing power of the BPLE and LPLE was also higher than that of the PLE, and more than twice as high at a concentration of 0.8 mg/ml or more. The ORAC value of the BPLE (79.77±0.82 uM TEs/extract g) was higher than that of the PLE (61.34±0.97 uM TEs/extract g). A WST-1 assay of the RAW 264.7 cells indicated that the PLE, BPLE, LPLE, SPLE and CPLE showed no cytotoxicity.