• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.1
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• pp.129-136
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• 2010

This study was initiated to investigate thatch accumulation in several turfgrasses grown under two soil systems. The 45 centimeter deep USGA system was constructed with rootzone, intermediate and drainage layers. The mono-layer system, however, was made with only a 30cm rootzone layer. Turfgrasses used in the study were comprised of 3 varieties from Korean lawngrass of Warm-Season Grass(WSG) and 3 blends and 3 mixtures from Cool-Season Grass(CSG). A total of 9 turfgrass treatments were replicated three times in RCBD in both systems. Cultural practices for the research plot followed a typical maintenance program for highly managed turf. Treatment differences for thatch accumulation were observed among the turfgrasses in both soil systems. Thatch under the USGA system was 9% greater than under the mono-layer system due to its more favorable conditions for turf growth. Higher thatch depth was found with Korean lawngrass, 34~87% in the USGA system and 16~75% in the mono-layer system when compared with CSG. Among WSG, the Joongji variety was the highest in thatch layer under both the USGA and mono-layer systems. Kentucky bluegrass(KB) was the greatest among CSG, since it is a rhizomatous-type in growth habit, resulting in faster production of organic matter over bunch-type of tall fescue and perennial ryegrass. Proper depth in the thatch layer was known to be beneficial by enhancing the resiliency and wear tolerance of the turf in athletic fields. Thus, KB was considered to be a very excellent turfgrass in terms of turf quality, environmental performance, physical properties and soccer player safety. However, disadvantages such as poor water-holding properties, more inclined to injury from environmental stresses and severe diseases and insect injury were also expected where thatch was excessively accumulated. Therefore, these results demonstrate that more frequent measures for controlling thatch such as vertical mowing, topdressing or coring should be employed for soccer fields with Korean lawngrass and KB over other turfgrasses.

• Korean Chemical Engineering Research
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• v.51 no.4
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• pp.418-425
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• 2013

The catalytic conversion of ethanol to aromatic compounds ETA was studied over ZSM-5 heterogeneous catalysts. The effect of reaction temperature, weight hourly space velocity (WHSV), and addition of water and methanol, which are the potential impurities of bio-ethanol, on the catalytic performance was investigated in a fixed bed reactor. Commercial ZSM-5 catalysts having different Si/$Al_2$ ratios of 23 to 280 and modified ZSM-5 catalysts by addition of metal (Zn, La, Cu, and Ga) were used for the activity and stability tests in ETA reaction. The catalysts were characterized with ammonia temperature programmed desorption ($NH_3$-TPD) and nitrogen adsorption-desorption techniques. The results of catalytic performance revealed that the optimal Si/$Al_2$ ratio of ZSM-5 is about 50~80 and the selectivity to aromatic compounds decreases in the order of Zn/La > Zn > La > Cu > Ga for the modified ZSM-5 catalysts. Among these catalysts from the ETA reaction, Zn-La/ZSM-5 showed the best catalytic performance for the ETA reaction. The selectivity to aromatic compounds was 72% initially and 56% after 30 h over the catalysts at reaction temperature of $437^{\circ}C$ and WHSV of $0.8h^{-1}$.

• KSBB Journal
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• v.19 no.2
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• pp.93-97
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• 2004

We investigate the effect of enzyme pretreatment using protease, carbohydrase, and lipase on improvement of sludge treatment efficiency by measuring SCOD and TCOD. The enzyme-pretreatment increases SCOD of excess sludge. In addition, the amount of sludge reduction during digestion, in terms of SCOD and TCOD, are enhanced by enzyme-pretreatment. Among pretense, carbohydrase, and lipase, pretense showed the best enhancement of the sludge treatment efficiency. Sludge digestion followed by ozone and enzyme treatments showed more effective sludge treatment when compared with ozone treatment alone. Therefore, we expect that enzyme pretreatment can be used as a useful tool for enhancing the sludge treatment efficiency.

• Korean Chemical Engineering Research
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• v.44 no.2
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• pp.179-186
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• 2006

Two types of $TiO_2$, nanotube and nanoparticle, were used for the mesoporous coatings by doctor blade technique followed by calcining at $450^{\circ}C$. The coatings were used as working materials for dye-sensitized solar cells (DSCs) later on and their photovoltaic characterization was carried out. The nanoparticle was synthesized from hydrogen titanate nanotube by hydrothermal treatment at $180^{\circ}C$ for 24 hr. The solar energy conversion efficiency (${\eta}$) of DSCs prepared by this nanoparticle reached 8.07％ with $V_{OC}$ (open-circuit potential) of 0.81 V, $I_{SC}$ (short-circuit current) of $18.29mV/cm^2$, and FF (fill factor) of 66.95％, respectively. For the preparation of nanotube, the concentration of NaOH solution varied from 3 M to 5 M. In the case of DSCs fabricated with nanotubes from 3 M NaOH solution, the ${\eta}$ reached 6.19％ with $V_{OC}$ of 0.77 V, $I_{SC}$ of $12.41mV/cm^2$, and FF of 64.49％, respectively. On the other hand, in the case of 5 M solution, the photovoltaic ${\eta}$ was decreased with 4.09％ due to a loss of photocarriers. In conclusion, it is demonstrated that the solar energy conversion efficiency of DSCs made from $TiO_2$ nanoparticle showed best results among those under investigation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.2
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• pp.167-175
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• 2005

Houttuynia cordata THNUB (He; Uh-Sung-Cho) is a medicinal plant which has been widely used as a component of blood-building decoctions. This study was performed to investigate the immunomodulative effect of He in mice. In vitro experiment, the mice splenocytes proliferation and three kinds of cytokines (IL-1$\beta$, IL-6, TNF- $\alpha$) production by mice peritoneal macrophages cultured with six (methanol, hexane, chloroform, ethylacetate, butanol and water) fractions of He were used to indicate the immunomodulative effect. Ex vivo experiment, the different concentrations of He water extract was orally administrated every other day for two weeks. The production of cytokines IL-1$\beta$, IL-6, TNF- $\alpha$) secreted by activated macrophages and the mice splenocytes proliferation were used as an index for the immunocompetence. The supplementation of all six fractions of He enhanced the splenocytes proliferation at the level of 6.58$\pm$1.23∼47.82$\pm$5.48 compared to that of control in the range of 1∼50 $\mu\textrm{g}$/mL. IL-1$\beta$ production was significantly increased with the supplementation of chloroform and water extract of He. Higher level of IL-6 production was detected by the supplementation of ethylacetate, butanol and water extract. TNF - $\alpha$ production was enhanced by the supplementation of all six fractions of He. From the ex vivo study, the highest proliferation of splenocytes was seen from the mice orally administrated with the He water extract at the concentration of 500 mg/kg bw In case of cytokines production, IL-1$\beta$, IL-6, and TNF- $\alpha$ release by activated peritoneal macrophages were augmented by the oral administration of He water extract. These results indicated that He may enhance the immune function by regulating the splenocytes proliferation and cytokines production capacity in mice.

• Journal of dental hygiene science
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• v.10 no.4
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• pp.265-271
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• 2010

This study was to investigate the level of knowledge, recognition, behavior of radiographic safety control and job stress in dental hygienists and to determine the relationship among variables. The subjects were 256(56.9%), who were worked in dental hospital and clinic with mean age of $29.59{\pm}7.30$. Data was collected using a self administrated questionnaire from April 4 to May 15, 2010. Behavior of radiographic safety control was measured using the 15-items and job stress was measured using the 5-items with 5-point likert scale. The data were analyzed with t-test, one-way ANOVA and pearson correlation coefficient using the SPSS WIN 17.0 program. Regarding job stress, the subjects was a mean of 2.63 out of a maximum 5 points. The level of knowledge, recognition, behavior of radiographic safety control a mean of 3.11, 4.08 and 3.43 out of a maximum 5 points. Recognition and behavior of radiographic safety control was negative related job stress in this study. Based on the findings, behavior of radiographic safety control is associated with job stress. These results suggest that various program should be considered for radiation safety control of dental hygienists.

• Journal of dental hygiene science
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• v.17 no.2
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• pp.134-141
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• 2017

This study examined 191 pregnant women before delivery in an obstetrics and gynecology clinic in North Gyeongsang Province from May to September 2016 by using a questionnaire after obtaining informed consent for voluntary participation in the study. The study was performed to investigate the association of depression with sociodemographic characteristics, pregnancy-related characteristics, social support, sleep quality and Oral Health Impact Profile (OHIP) in pregnant women. The prevalence of depression among the pregnant women was 25.1% in the healthy group and 74.9% in the depression group. The depression level was significantly higher in women in the depression group who were unsatisfied with their marriage life, had no occupation, had lower social support, had poor sleep quality and had higher OHIP scores. The results of the logistic regression analysis indicated that, the risk ratio for more severe depression was significantly higher in the group with no experience of miscarriage and induced childbirth than in the group with childbirth experience. Conversely, the risk ratio for more severe depression was significantly lower in the group with high social support than in the group with low social support. Depression in the respondents significantly positively correlated with sleep quality and OHIP score but significantly negatively correlated with social support. The multiple regression analysis revealed that the depression level was significantly higher by 22.3% among pregnant women with lower marital satisfaction, no childbirth experience, lower social support and higher OHIP scores. In summary, depression was related to marital satisfaction, childbirth experience, social support, and OHIP score, among others, in pregnant women in this study. Therefore, further investigation is warranted to construct programs and measures that will help build positive thinking by designing and verifying a three-dimensional study model by taking into consideration various variables to reduce the incidence of depression in pregnant women.

• Journal of the East Asian Society of Dietary Life
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• v.26 no.1
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• pp.88-98
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• 2016

The pharmacological effects of ginseng berry have been known to improve psychological function, immune activities, cardiovascular conditions, and certain cancers. It is also known that fermentation improves the bioavailability of human beneficial natural materials. Accordingly, we investigated the optimal fermentation conditions of ginseng berry extract with strain isolated from conventional foods. We also analyzed the fermentation product and its antioxidant activity. The bacterium isolated from fermented kimchi was identified as Lactobacillus sp. strain KYH. To optimize the process, fermentation was performed in a 5 L fermenter containing 3 L of ginseng berry extract at 200 rpm for 72 hr. Under optimized conditions, batch and fed-batch fermentations were performed. After fermentation, organic acids, amino acids, sugars, ginsenosides, and antioxidant activity were evaluated. The optimum fermentation conditions were determined as pH 7.0 and a temperature of $30^{\circ}C$, respectively. After fermentation, the amounts and compositions of organic acids, amino acids, sugars, ginsenosides, and antioxidant activity were altered. In comparing the distribution of ginsenosides with that before fermentation, the ginsenoside Re was a major product. However, amounts of ginsenosides Rb1, Rc, and Rd were reduced, whereas amounts of ginsenosides Rh1 and Rh2 increased. Total phenol content increased to 43.8%, whereas flavonoid content decreased to 19.8%. The DPPH radical scavenging activity and total antioxidant activity increased to 27.2 and 19.4%, respectively.

• Korean Journal of Environment and Ecology
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• v.21 no.3
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• pp.197-206
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• 2007

This study was conducted to survey the population of water birds wintering at the seven coastal wetlands of Jeollanam province including Suncheon Bay and Yeongsan Lake, from 2000 through 2003. The 90 species and 857,570 individuals in total were sighted at the seven survey sites. We classified the wintering water birds into seventeen groups of taxa based on the similar ecological attributes, among which, eight groups were found to inhabit the water surface or riparian areas. Classified groups that showed higher rate of using bay areas than that of lake areas were in the order of waders, gulls and swans. On the other hand, the groups that showed higher rate of using lake areas than that of using bay areas were revealed in the order of dabbling ducks, grebes and geese. In conclusion, there was a difference in the pattern between the two classified groups. As a result of the UPGMA cluster analysis using CCs ($S{\varnothing}rensen'a$ index of similarity and Ro (Horn's index of community overlap), the results showed that Suncheon Bay had the most unique species formation out of the seven areas. Bay and lake areas were different from each other in the formation of species and Individuals. As a result of combining the index rank according to the maximum aggregate count, the Suncheon Bay is ranked the highest in importance of the habitats for water birds, followed by the order of Boseong-Deukryang Bay, Gangjin Bay, Gocehongam Lake, Geumho Lake, Yeomam Lake, and Yeongsan Lake. Considered overall, the importance of the bay areas was relatively higher than that of reclaimed lake areas.

• Korean Journal of Environment and Ecology
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• v.28 no.6
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• pp.751-761
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• 2014

This study was carried out to analyze the vegetation properties, soil characteristics and ordination of Rhododendron brachycarpum population in South Korea. Rhododendron brachycarpum were mainly distributed along the Ulleungdo and Baekdudaegan of the Korean penninsula and it's population was located at an elevation of 872m to 1466m. The Rhododendron brachycarpum population was classified into Taxus cuspidata var. latifolia dominant population, Magnolia sieboldii dominant population, Thuja koraiensis dominant population and Rhododendron brachycarpum typical population. The composition of soil properties in the same areas are as follows: organic matter, total nitrogen, available phosphorous, exchangeable $K^+$, exchangeable $Ca^{2+}$, exchangeable $Mg^{2+}$ contained, and soil pH. The capacities of these chemical properties of the soil ranged from 10.45~15.28%, 0.37~0.61%, $0.21{\sim}0.35cmol^+/kg$, $0.39{\sim}2.54cmol^+/kg$, $0.17{\sim}0.50cmol^+/kg$, $18.28{\sim}22.81cmol^+/kg$ and 4.66~5.23 respectively. The results of the correlation between communities and soil conditions of vegetation of Rhododendron brachycarpum by DCCA ordination method are as follows: Taxus cuspidata var. latifolia dominant population was found in the very steep sloped area that has low percentage of total organic matter and nitrogen than other populations. Magnolia sieboldii dominant population and Thuja koraiensis dominant population was found in the steep sloped area that has high percentage of total organic matter and nitrogen than other populations. Thuja koraiensis dominant population was found in the gentle sloped area that has high percentage of altitudinal and rock exposure. Current status of Rhododendron brachycarpum is very vulnerable with a collection of herbs constantly threatening the species' survival. Thus, concrete conservation plans to protect natural habitats should be set up as soon as possible.