• The Korean Journal of Financial Management
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• v.24 no.2
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• pp.41-79
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• 2007

This study examines the expiration-day effects of stock index futures and options in the Korean stock market. The so-called 'expiration-day effects', which are the abnormal stock price movements on derivatives expiration days, arise mainly from cash settlement. Index arbitragers have to bear the risk of their positions unless they liquidate their index stocks on the expiration day. If many arbitragers execute large buy or sell orders on the expiration day, abnormal trading volumes are likely to be observed. If a lot of arbitragers unwind positions in the same direction, temporary trading imbalances induce abnormal stock market volatility. By contrast, if some information arrives at market, the abnormal trading activity must be considered a normal process of price discovery. Stoll and Whaley(1987) investigated the aggregate price and volume effects of the S&P 500 index on the expiration day. In a related study, Stoll and Whaley(1990) found a similarity between the price behavior of stocks that are subject to program trading and of the stocks that are not. Thus far, there have been few studies about the expiration-day effects in the Korean stock market. While previous Korean studies use the KOSPI 200 index data, we analyze the price and trading volume behavior of individual stocks as well as the index. Analyzing individual stocks is important for two reasons. First, stock index is a market average. Consequently, it cannot reflect the behavior of many individual stocks. For example, if the expiration-day effects are mainly related to a specific group, it cannot be said that the expiration of derivatives itself destabilizes the stock market. Analyzing individual stocks enables us to investigate the scope of the expiration-day effects. Second, we can find the relationship between the firm characteristics and the expiration-day effects. For example, if the expiration-day effects exist in large stocks not belonging to the KOSPI 200 index, program trading may not be related to the expiration-day effects. The examination of individual stocks has led us to the cause of the expiration-day effects. Using the intraday data during the period May 3, 1996 through December 30, 2003, we first examine the price and volume effects of the KOSPI 200 and NON-KOSPI 200 index following the Stoll and Whaley(1987) methodology. We calculate the NON-KOSPI 200 index by using the returns and market capitalization of the KOSPI and KOSPI 200 index. In individual stocks, we divide KOSPI 200 stocks by size into three groups and match NON-KOSPI 200 stocks with KOSPI 200 stocks having the closest firm characteristics. We compare KOSPI 200 stocks with NON-KOSPI 200 stocks. To test whether the expiration-day effects are related to order imbalances or new information, we check price reversals on the next day. Finally, we perform a cross-sectional regression analysis to elaborate on the impact of the firm characteristics on price reversals. The main results seem to support the expiration-day effects, especially on stock index futures expiration days. The price behavior of stocks that are subject to program trading is shown to have price effects, abnormal return volatility, and large volumes during the last half hour of trading on the expiration day. Return reversals are also found in the KOSPI 200 index and stocks. However, there is no evidence of abnormal trading volume, or price reversals in the NON-KOSPI 200 index and stocks. The expiration-day effects are proportional to the size of stocks and the nearness to the settlement time. Since program trading is often said to be concentrated in high capitalization stocks, these results imply that the expiration-day effects seem to be associated with program trading and the settlement price determination procedure. In summary, the expiration-day effects in the Korean stock market do not exist in all stocks, but in large capitalization stocks belonging to the KOSPI 200 index. Additionally, the expiration-day effects in the Korean stock market are generally due, not to information, but to trading imbalances.

• Journal of the East Asian Society of Dietary Life
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• v.25 no.1
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• pp.183-192
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• 2015

This study aimed to produce fermented extracts with sugar made from lotus root (LR) and Platycodon grandiflorum (PG), using lactic acid fermentation, and confirmed their physiological and anti-oxidative activities as basic data for manufacturing functional drinks through sensory tests. For the final sugar concentrations, PG showed $48.1^{\circ}brix$ and LR showed $52.0^{\circ}brix$. Sugar concentrations during lactic acid fermentation following dilution of sugar to $12^{\circ}brix$, ranged from $11.5{\sim}12.1^{\circ}brix$ for PG and $11.9{\sim}12.4^{\circ}C$ for LR. During lactic acid fermentation, lactic acid bacteria numbers tended to decrease in both fermented LR and PG extracts with sugar as the fermentation period increased. For DPPH radical scavenging ability, LR was three times higher in control without lactic acid fermentation while PG showed significant increases in L. acidophilus (77%), L. brevis (90%), and L. delbrueckii (177%) during lactic acid fermentation. For total polyphenol content, LR showed a higher concentration than PG, and except for fermented L. delbrueckii extract showing similarity with the control, contents of fermented extracts decreased. In the case of PG, CUPRAC, increased significantly in L. brevis, whereas FRAP, increased significantly in L. delbrueckii with lactic acid fermentation. For reducing power, except for fermentation with L. brevis, all PG showed lower reducing power activities. In the sensory test of fermented LR and PG extracts with sugar, both fermented extracts showed better results with L. brevis or L. delbrueckii than control or those with L. acidophilus in every item. Based on these results, it is highly possible to develop fermented extract drinks with sugar using LR or PG. In particular, lactic acid bacteria such as L. delbrueckii and L. brevis showed generally higher activities with potential as a functional drink.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.3
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• pp.265-272
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• 2012

Purpose: To compare the results on myopia correction with reverse geometry lenses, effects of wearing reverse geometry lenses were evaluated for the children with low-level and high-level myopia. Methods: The research investigated the corrective effects of having worn reverse geometry lenses for one week, one month, three months and six months on a total of thirty-six persons (sixty-two eyes) between the ages of seven and fifteen, divided into three groups by the degree of their myopia; nineteen eyes(Group One) with myopia of -2.00 D and under, twenty-eight eyes(Group Two) with myopia between -2.25 D and -4 D, and fifteen eyes(Group Three) with myopia of -4.25 D and above; as shown by changes in uncorrected vision and the degree of refraction in the corneal topography, and tested for statistical similarity among the pursued results. Results: After wearing reverse geometry lenses, Group One showed an improvement in vision of 0.5, from 0.45 to 0.95, after one week, and improvements to 0.91 after one month and 1.02 after three months but, after six months, the group's vision regressed to 0.95. Group Two showed an improvement in vision of 0.43, from 0.34 to 0.77, after one week of wearing and to 0.91 after one month, to 0.97 after three months and this was statistically maintained through the remainder of six months. Group Three showed an improvement in vision of 0.55, from 0.15 to 0.7, after wearing for one week, to 0.87 after one month and to 0.91 after three months but saw a regression to 0.86 after six months. The average Sim K (simulated keratometry reading) value for Group One started from $42.84{\pm}1.17D$ and decreased to $41.48{\pm}0.98D$ after one week of wearing and continued declining through three months before increasing during the remainder of six months. Group Two began from $42.91{\pm}1.57D$ and recorded $41.78{\pm}1.58 D$ after one week, continuing the decline through three months before increasing during the remainder of six months. Group Three began at $42.64{\pm}1.64D$ and showed its Sim K value decrease to $40.77{\pm}1.20D$ after one week of wearing, increase after one month and decrease after three months and continue the decline through the remainder of six months. Conclusions: From the results of this study, wearing reverse geometry lenses had myopia-correcting effects after one week of wearing. Although there were variations in the time for such effect to take place but myopia-correcting effects were evident in all test groups.

• Horticultural Science & Technology
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• v.31 no.6
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• pp.772-781
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• 2013

The objective of this study was to develop simple sequence repeat (SSR) markers from expressed sequence tags (EST) of lettuce (Lactuca sativa) and identify 9 germplasms from 3 wild species of lettuce and 61 commercial cultivars using the developed EST-SSR markers. A total of 81,330 lettuce ESTs from NCBI databases were used to search for SSR and 4,229 SSR loci were identified. The highest proportion (59.12%, 2500) was represented by trinucleotide, followed by dinucleotide (29.70%, 1256) and hexanucleotide (6.62%, 280) among SSR repeat motifs. Totally 474 EST-SSR primers were developed from EST and a random set of 267 primers was used to assess the genetic diversity among 9 germplasms and 61 cultivars. Out of 267 primers, 47 EST-SSR markers showed polymorphism between 7 cultivars. Twenty-six EST-SSR markers among 47 EST-SSR markers showed high polymorphism, reproducibility, and band clearance. The relationship between 26 markers genotypes and 70 accessions was analyzed. Totally 127 polymorphic amplified fragments were obtained by 26 EST-SSR markers and two to nine SSR alleles were detected for each locus with an average of 4.88 alleles per locus. Average polymorphism information content was 0.542, ranging from 0.269 to 0.768. Genetic distance of clusters ranged from 0.05 to 0.94 between 70 accessions and dendrogram at a similarity of 0.34 gave 7 main clusters. Analysis of genetic diversity revealed by these 26 EST-SSR markers showed that the 9 germplasms and 61 commercial cultivars were discriminated by marker genotypes. These newly developed EST-SSR markers will be useful for cultivar identification and distinctness, uniformity and stability test of lettuce.

• Food Science of Animal Resources
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• v.33 no.3
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• pp.403-410
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• 2013

This study was performed to evaluate the microbiological contamination level of raw beef from retail markets in Seoul, Korea. The sampling and laboratory test were performed according to the procedure of "Standard for processing and ingredients specification of livestock product" and "Korean food code". Enterotoxin of Staphylococcus aureus isolates were detected using VIDAS$^{(R)}$ and PCR-based methods. Listeria monocytogenes serotyping and genotyping were carried out using Listeria antisera and L. monocytogenes Fingerprinting kit, respectively. A total of 48 samples were collected from 16 retail markets (butcher's shop: 5, department store: 6, supermarket: 5) in 2011. The level of total bacteria counts in the butcher's shop, department store and supermarket were $4.4{\times}10^3$ CFU/g, $3.9{\times}10^5$ CFU/g and $1.0{\times}10^4$ CFU/g, respectively. The concentrations of Escherichia coli of these three retail markets were $6.4{\times}10$ CFU/g, 7.6 CFU/g and $2.0{\times}10$ CFU/g, respectively. Salmonella species was not detected on all samples. However, S. aureus was isolated in the 3 samples (6.25%) from each type of three retail markets. L. monocytogenes was isolated in the 4 samples (8.3%) from department stores. The level of contamination of these foodborne bacteria was less than 100 CFU/g. The enterotoxin-encoding genes of S. aureus isolates were sea, seh, sei and sep gene. The gene similarity of L. monocytogenes isolated from two retail markets by Rep-PCR showed 57.8-98.1% and 68.1-98.1%, respectively. These results suggest that the HACCP guideline for environmental control in slaughterhouse and retail markets should be provided to prevent cross contamination and manage foodborne pathogens such as L. monocytogenes and S. aureus.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.2
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• pp.344-356
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• 2005

There are normal inhabitants doing medically useful functions in the body. There are many kinds of bacteria performing specific functions in the oral cavity. Two strains of lactic acid bacteria were isolated from inhabitants of caries-free children's oral cavity, which inhibited the formation of artificial plaque by Streptococcus mutans and the production of volatile sulfur compounds by anaerobic bacteria. The isolates were identified by the test using API 50 CHL medium kit and 16S rDNA partial sequencing. 1. Two isolates were Gram-positive bacilli and produced hydrogen peroxide. 2. When Streptococcus mutans was cultured in the media, the mean weight of formed artificial plaque on the orthodontic wires was $124.4{\pm}30.4\;mg$, whereas being reduced to $5.2{\pm}2.0mg$ and $10.6{\pm}6.6mg$ in the media cultured with Streptococcus mutans and each isolate, respectively (p<0.05) 3. The number of viable cells of Streptococcus mutans was $3.4{\times}10^9$ per ml in the cultured solution, whereas those of Streptococcus mutans in the combined culture with each of isolates were $4.6{\times}10^8\;and\;2.4{\times}10^8$ per ml. 4. The optical density was 1.286 in the supernatant of Fusobacterium nucleatum after vortexing for 30minutes, whereas in the supernatant of combined Fusobacterium nucleatum and each isolate, they were reduced to 0.628 and 0.497, which the percentages of coaggregation between them were 29.4% and 57.8%, respectively 5. The optical density of Fusobacterium nucleatum precipitate was 1.794 in the culture media containing cysteine and $FeSO_4$, being reduced to 1.144 and 0.915 in the coaggregated precipitates of Fusobacterium nucleatum and each isolate. The optical density of Porphyromonas gingivalis precipitate was 1.932 in the culture media, being reduced to 1.170 and 1.266 in the coaggregated precipitates of Porphyromonas gingivalis and each isolate. 6. When two isolates were tested with API 50 CHL medium kit, those were identified Lactobaciallius salivarius and Lactobaciallius delbrueckii subsp. lactis. 7. The similarity values of 16S rDNA sequence between each of isolates and Lactobaciallius salivarius subsp. salicinius were 99.60% and 99.73%, respectively, meaning that isolates were Lactobaciallius salivarius subsp. salicinius. These results indicated that two strains isolated from caries-free children's saliva, which inhibited the formation of artificial plaque and the production of volatile sulfur compounds, were identified as Lactobaciallius salivarius subsp. salicinius.

• Tuberculosis and Respiratory Diseases
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• v.46 no.3
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• pp.338-349
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• 1999

Polymorphonuclear leukocytes(PMN) are the predominant inflammatory cells recruited in acute lung injury such as adult respiratory distress syndrome, pneumonia and also chronic lung disease such as idiopathic pulmonary fibrosis and pulmonary emphysema. Interleukin-8(IL-8) is an 8,000 D protein produced by many cells and has potent neutrophil chemoattractant and activating properties. The GRO, also called melanoma growth-stimulatory activity(MGSA), referring to a peptide of 73 amino acids, was reported to be mitogenic for cultured human melanoma cells. Mature GRO/MGSA has marked sequence similarity to IL-8. In view of the structural similarities to IL-8, it was of particular interest to test GRO for neutrophil activating and chemotactic properties. We found a significant release of IL-8 and GRO/MGSA from the cultured human umbilical vein endothelial cell(HUVEC) which was stimulated either with TNF$\alpha$ or IL-1$\beta$ and also found the expression of IL-8 and GRO/MGSA mRNA. Neutrophil chemotactic activity was enhanced in accordance with the increased IL-8 and GRO/MGSA. Our study also suggest that the IL-8 is more important in the increased neutrophil chemotactic activity than GRO/MGSA when endothelial cell is stimulated with TNF$\alpha$ or IL-1$\beta$ in vitro.

• The Korean Journal of Soil Zoology
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• v.6 no.1_2
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• pp.25-31
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• 2001

Oribatid mite communities in the process of litter decomposition were analyzed In Korean pine (Pinus koraiensis) forests of Namsan and Kwangreung, which were supposed to be under different environmental selective pressures. Oribatid mites were collected bimonthly from the litter bags (mesh size 0.4 mm, 1.7 mm) which was set up in the forest floor of study sites. This study had been carried out from Jan., 1997 to Sept., 1998. Species abundance of Kwangreung (mesh size 1.7 mm) was significantly higher than that of Namsan (mesh size 1.7 mm), but total no. of species did not exceed 30 species in all study sites. Concerning body length, medium sized oribatid mites (0.3-0.7mm) were more abundant than small ( < 0.3 mm) and large ( > 0.7 mm) sized mites. In Kwangreung, species whose body lengths were 0.2 mm to 0.5 mm were major group. However, a little larger species than Kwangreung's major group were dominant in Namsan. Sorenson similarity index and cluster analysis suggested that there were qualitative and quantitative differences in species composition in Namsan and Kwangreung. More species were collected in May through September than the other sampling times, but the pattern was rather different between first year and second year. Newly immigrant species were high in May in the first year and many of them regained on next year. Diversity indices suggested that species diversity of Kwangreung was higher than that of Namsan. Nearly 70% of total individual abundance was occupied by several dominant species in Namsan and Kwangreung . In the litter bags of mesh size 1.7 mm, the most dominant species was Trichogalumna nipponica in Namsan and Kwangreung, but in the litter bags of mesh size 0.4 mm in Kwangreung it was Ramusella sengbuschi which is smaller than T. nipponica. And important species related to litter decomposition were selected as follows; T. nipponica, Epidamaeus coreanus, Scheloribates latipes, Ceratozetes japonicus, Ramusella sengbuschi, Eohypochthonius crassisetiger, and Cultroribula lata.

• Economic and Environmental Geology
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• v.8 no.3
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• pp.147-164
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• 1975

19 amphibolite samples from the Precambrian Sobaegsan metamorphic belt including the Ogbang mine amphibolites were analyzed for 24 elements each, by wet chemical and emission spectroscopic methods. All the chemical data were evaluated by the methods outlined by Evans and Leake(1960) and Leake(1964) and by Shaw and Kudo(1965). The chemical similarity of all the studied rocks analyzed to basic igneous rocks is consistently indicated particularly by trace element abundance and variation trends. Petrography and oxidation ratios were also considered in attempting to determine the nature of the parent rocks. 3 analyses of W-bearing mafic metamorphic rocks from Sangdong area of the Ogcheon geosynclinal zone are also presented and discussed. Geochemical data for these latter rocks have been possibly derived from mafic tuffs deposited in an area of carbonate deposition.

• Korean Journal of Microbiology
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• v.53 no.2
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• pp.83-96
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• 2017

A constructed sea stream in Yeongdo, Busan, Republic of Korea is mostly static due to the lifted stream bed and tidal characters, and receives domestic wastewater nearby, causing a consistent odor production and water quality degradation. Bioaugmentation of a microbial consortium was proposed as an effective and economical restoration technology to restore the polluted stream. The microbial consortium activated on site was augmented on a periodic basis (7~10 days) into the most polluted site (Site 2) which was chosen considering the pollution level and tidal movement. Physicochemical parameters of water qualities were monitored including pH, temperature, DO, ORP, SS, COD, T-N, and T-P. COD and microbial community analyses of the sediments were also performed. A significant reduction in SS, COD, T-N, and COD (sediment) at Site 2 occurred showing their removal rates 51%, 58% and 27% and 35%, respectively, in 13 months while T-P increased by 47%. In most of the test sites, population densities of sulfate reducing bacterial (SRB) groups (Desulfobacteraceae_uc_s, Desulfobacterales_uc_s, Desulfuromonadaceae_uc_s, Desulfuromonas_g1_uc, and Desulfobacter postgatei) and Anaerolinaeles was observed to generally decrease after the bioaugmentation while those of Gamma-proteobacteria (NOR5-6B_s and NOR5-6A_s), Bacteroidales_uc_s, and Flavobacteriales_uc_s appeared to generally increase. Aerobic microbial communities (Flavobacteriaceae_uc_s) were dominant in St. 4 that showed the highest level of DO and least level of COD. These microbial communities could be used as an indicator organism to monitor the restoration process. The alpha diversity indices (OTUs, Chao1, and Shannon) of microbial communities generally decreased after the augmentation. Fast uniFrac analysis of all the samples of different sites and dates showed that there was a similarity in the microbial community structures regardless of samples as the augmentation advanced in comparison with before- and early bioaugmentation event, indicating occurrence of changing of the indigenous microbial community structures. It was concluded that the bioaugmentation could improve the polluted water quality and simultaneously change the microbial community structures via their niche changes. This in situ remediation technology will contribute to an eco-friendly and economically cleaning up of polluted streams of brine water and freshwater.