• The Korean Journal of Financial Management
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• v.25 no.2
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• pp.165-190
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• 2008

The degree of informational asymmetry relating to the expiration of index derivatives is usually increased as an expiration day of index derivatives approaches. The increase in the degree of informational asymmetry may have some effects on trading behavior of investors. To examine what the effects look like, 'life cycle of index derivatives' in this study is defined as three adjacent periods around expiration day: pre-expiration period(a week before the expiration day), post-expiration period(a week after the expiration day), and remaining period. It is inspected whether stock investor's trading behavior is changed according to the life cycle of KOSPI200 derivatives and what the reason of the changing behavior is. We have four results. First, trading behavior of each investor group is categorized into three patterns: ㄱ-pattern, L-pattern and U-pattern. The level of trading activity is low for pre-expiration period and normal for other periods in the ㄱ-pattern. L-pattern means that the level of trading activity is high for post-expiration period and normal for other periods. In the U-pattern, the trading activity is reduced for remaining period compared to other periods. Second, individual investors have ㄱ-pattern of trading large stocks according to the life cycle of KOSPI200 index futures while they show U-pattern according to the life cycle of KOSPI200 index options. Their trading behavior is consistent with the prediction of Foster and Viswanathan(1990)'s model for strategic liquidity investors. Third, trading pattern of foreign investors in relation to life cycle of index derivatives is partially explained by the model, but trading pattern of institutional investors has nothing to do with the predictions of the model.

• Clinical and Experimental Pediatrics
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• v.46 no.7
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• pp.695-701
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• 2003

Purpose : It had been suggested that pain arising from deep somatic body regions influences neural activity within periaqueductal gray(PAG) of midbrain via distinct spinal pathways. Aspirin is one of the popular non-steroidal anti-inflammatory drugs used in the management of pain. Fos expression was used as a marker for neuronal activity throughout central neurons following painful peripheral stimulation. This study was prepared to investigate changes of c-Fos immunoreactivity in midbrain by deep pain and effects of aspirin. Methods : Male Sprague-Dawley rats were injected with 0.1 mL of 5% formalin in the plantar muscle of the right hindpaw. For experimental group II, aspirin was injected intravenously before injection of formalin. An aspirin-untreated group was utilized as group I. Rats were sacrificed at 0.5, 1, 2, 6 and 24 hours after formalin injection. Rat's brains were removed and sliced in rat brain matrix. Brain slices were coronally sectioned at interaural 1.00-1.36 mm. Serial sections were immunohistochemically reacted with polyclonal c-Fos antibody. The numbers of c-Fos protein immunoreactive neurons in ventrolateral periaqueductal gray(VLPAG) and dorsomedial periaqueductal gray(DMPAG) were counted and analyzed statistically with Mann-Whitney U tests. Results : Higher numbers of c-Fos protein immunoreactive neurons were found in VLPAG. In both VLPAG and DMPAG of formalin-treated group, the numbers of c-Fos protein immunoreactive neurons were significantly higher at all time points than the formalin-untreated group, which peaked at two hours. The numbers of c-Fos immunoreactive neuron of the aspirin-treated group were less compared to the aspirin-untreated group at each time point. Conclusion : These results provide some basic knowledge in understanding the mechanism of formalin-induced deep somatic pain and the effects of aspirin.

• Journal of Chest Surgery
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• v.29 no.4
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• pp.373-380
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• 1996

Prevention of thromboembolism is the most important task in the development of bioconpatible small caliber artificial vascular graft. In normal vessels, vascular endothelial cells maintain homeosatsis by secreting numerous factors. The aim of this study is to develope a method which Improves biocompatibility of small caliver polyurethane graft using endothelial cell culture technique, and ev luate the efTectiveness of extracelluar matrix for endothelization which was produced by cultured fibroblast. Methods ; Multiporous polyurethane tube of 3 mm diameter, 0.3 mm thickness was manufactured for vascular graft. Three mongrel dogs were intubated and internal jugular veins removed. Extracelluar matrix produced by cultured flbrobast which was obtained from dog's internal jugular vein were coated to the polyurethane graft. Then, endothelial cells extracted from Jugular vein were cultured and fixed on the extracelluar matrix layer of vascular graft. Endothelial cell coated vascular grafts were implanted to the carotid arteries of experimental dogs as interposed autograft. Implanted grafts were removed after 3 and 6 weeks. As a control, PTFE graft was interposed on carotid artery. These experiments demonstrated that extracelluar matrix produced by fibroblast can afford a base for endothelial cell linings of polyurethane graft. Although thrombosis were developed on autografted en othelial cell coated graft, 33% opening was noticed, and showed less adhesion to adjacent tissue layer. These findings suggest that fiboblast produced extracelluar matrix which can be used for edothelial cell lining vascular graft, and by improving the cultured endothelial cell function, there will be a new modality for reducing thrombosis on small vascular graft.

• Clinical and Experimental Pediatrics
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• v.48 no.5
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• pp.539-544
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• 2005

Purpose : The aim of this study was to investigate the pathophysiologic role of serum E-selectin, vascular endothelial growth factor(VEGF)-induced cell adhesion mollecule in Kawasaki disease(KD) and to look for the evidence of direct relationship between the plasma levels of soluble E-selectin and the incidence of coronary artery lesion(CAL). Methods : Changes in plasma levels of sE-selectin(n=98) over time were measured by enzyme-linked immunosorbent assay(ELISA) in 23 patients with acute KD and 25 age-matched febrile children. Results : Compared with control values, the peak levels of plasma sE-selectin were significantly elevated($mean{\pm}S.E$. : $22.89{\pm}12.53ng/mL$ vs $10.65{\pm}3.42ng/mL$, P=0.01) in KD. 5 patients with CAL, plasma sE-selectin levels before treatment were higher than in 18 patients without CAL($mean{\pm}S.E$. : $39.43{\pm}15.08ng/mL$ and $19.00{\pm}8.32ng/mL$, respectively; P=0.01). Plasma sE-selectin declined rapidly in the majority of KD patients regardless of the presence of CAL. Plasma sE-selectin levels after treatment and convalesent period were similar in KD patients with and without CAL. The plasma levels sE-selectin were correlated with those of white blood cell count(r=0.299, P<0.05), CRP(r=0.430, P<0.05), serum albumin(r=-0.483, P<0.05), serum protein(r=-0.502, P<0.05) and hemoglobin(r=-0.372, P<0.05) not with those of ESR, platelet, or duration of fever. There were significant differences in the initial level of serum sE-selectin between KD with and without CAL($mean{\pm}S.E$. : $39.44{\pm}15.08ng/mL$ vs. $19.00{\pm}17.18ng/mL$) in multivariated linear tests. Conclusion : Plasma sE-selectin levels were significantly higher in KD than in other febrile illness. Higher plamsa levels of sE-selectin may have potential as a predictor of CAL in patients with KD.

• Journal of dental hygiene science
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• v.3 no.1
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• pp.45-50
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• 2003

In order to develop the program of oral hygiene education for elementary school senior-students, a questionnaire survey of elementary fourth, fifth and sixth students who are under continual control program of oral hygiene. (1) For tooth brushing time, after dinner is more than before. 73.7% of respondents brushed the teeth twice or more a day. (2) 62.1% of respondents took the cariogenic food twice or more a day. (3) 90.1% of respondents had visited a dental clinic. (4) Concerning fear for dental treatment, only 14.4% had a feeling of fear. (5) Regarding the experience with a preventive treatment, 39.7% had an experience with pit and fissure sealing, and 24.2% had an experience with the application of fluorides. (6) 46.2% of respondents had a preference for the fluoride mouth rinsing program, and 38.4% wanted that program to keep going on. As to the reason to favor the fluoride mouth rinsing program, 38.2% preferred it because of prevention of dental caries, and 43.0%, the largest percentage, didn't favor it because they found it too much trouble to do. (7) Comparing with the research result in 2000, we proved positively the educational effect of brushing frequency, positive understanding and preference to water school fluoridation program, and got the negative data of experience of visiting to oral clinic and preventive treatment.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.7 no.3
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• pp.181-190
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• 2012

After industrialization, the labor force participation rates of women, especially married women is drastically increasing. So, this study was designed to analyze the determinants of married women's employment status considered. For this, the determinants of married women's employment status were divided into individual-related, children-related, household-related and job-related variables to establish the research models. Based on this, the following results were drawn from a multinominal logistic regression analysis of the determinants of married women's employment status. First, an analysis of individual-related variable showed that married women had the employment status of labor wages with residence in the center of the city and high academic background. Second, an analysis of children-related variable showed that they had the employment status of labor wages with many their children and no their children under the age of six. Third, an analysis of household-related variable showed that they had the self-employment status of labor wages with nuclear family and few income earners of family members. Finally, an analysis of job-related variable showed that they had the employment status of labor wages when they got a job before they got married, their husband didn't get a job, and their husband worked in a professional field. As for findings stated above, as there was a difference in the determinants of married women's employment status, the ways for improvement in the married women's employment status would be suggested as follows. First, married women with young children have the low employment status, basically, requiring problem-solving ways for this because the housekeeping and child-rearing burden caused by marriage and childbirth are factors that continue to obstruct a job. For this, the flexible working hours system, which housekeeping and child-rearing can harmonize with economic activities like developed countries, needs to be activated. But the activation of such flexible working system will produce actual results under institutional protection, such as a related-protection law. Second, the Leave of Child Care System is debated as one of the most representatively systems that housekeeping can harmonize with economic activities. Now, although the System is legislated, the use is very poor.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.6
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• pp.423-433
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• 2019

In order to predict the seabed topography change due to the construction of offshore wind power structures in the west-southern sea of Korea, field observations for tides, tidal currents, suspended sediment concentrations and seabed sediments were carried out at the same time. These data could be used for numerical simulation. In numerical experiments, the empirical constants for the suspended sediment flux were determined by the trial and error method. When a concentration distribution factor was 0.1 and a proportional constant was 0.05 in the suspended sediment equilibrium concentration formulae, the calculated suspended sediment concentrations were reasonably similar with the observed ones. Also, it was appropriate for the open boundary conditions of the suspended sediment when the south-east boundary corner was 11.0 times, the south-west was 0.5 times, the westnorth 1.0 times, the north-west was 1.0 times and the north-east was 1.0 times, respectively, using the time series of the observed suspended sediment concentrations. In this case, the depth change was smooth and not intermittent around the open boundaries. From these calibrations, the annual water depth change before and after construction of the offshore wind power structures was shown under 1 cm. The reason was that the used numerical model for the large scale grid could not reproduce a local scour phenomenon and they showed almost no significant velocity change over ± 2 cm/s because the jacket structures with small size diameter, about 1 m, were a water-permeable. Therefore, it was natural that there was a slight change on seabed topography in the study area.

• Korean Journal of Environmental Biology
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• v.37 no.2
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• pp.217-227
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• 2019

The purpose of this study was to investigate the initial growth, burrowing depth, and relative growth of mud shrimps (Upogebia major and Austinogebia wuhsienweni), living in damaged high density tidal flat shellfish farms form 2008 in the Western coast of Korea. By August, young mud shrimps (Upogebia major), which had settled down on the tidal flats in early May, grew to more than 10 mm in carapace length (CL). At the end of the first year, their CL and total length (TL) increased to 14.21 mm and 42.28 mm, respectively. The inhabiting depth of the young mud shrimps (Upogebia major) increased rapidly up to about 6 months after stocking (5 cm in July, 12.5 cm in September, and 28 cm in November, respectively). The inhabiting depth of adult mud shrimps in their burrows was about 10-93 cm during the year. As results, the analysis of the relative growth between the carapace length (CL) - the total length (TL) and the CL - total wet weight (TWW), the total wet weight of mud shrimps at Boryeong Saho (inner part of the Cheonsu-bay) was estimated to be 1.2-4 g heavier than those of Boryeong Jugyo (Outer part of the Cheonsu-bay) tidal flat. The young mud shrimps primarily grew from April to October. It is therefore crucial to observe whether the settlement of young mud shrimps on tidal shellfish farms from May to June to minimize the damage of shellfish farms by newly stocked young mud shrimps. In addition, it is recommended that young mud shrimps grown in fisheries be harvested before they dig deep into the sediment until early December.

• Radiation Oncology Journal
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• v.16 no.2
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• pp.107-114
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• 1998

Purpose : Ginkgo biloba extract(GBE) is known to increase the peripheral blood circulation. This study was designed to evaluate the effect of GBE on the acute normal tissue radiation reaction. Materials and Methods : mice were divided into two groups, radiation alone and two doses GBE plus radiation, for both acute skin reaction and jejunal crypt assay. GBE was given i.p. one hour before irradiation with priming dose given one day earlier. Thirty to Fifty Gy for acute skin reaction and 11 to 14 Gy for jejunal crypt were irradiated to right hind leg and whole body, respectively. Results : Radiation doses($RD_{50}$) for Peak skin score of 2.0 were 44.2Gy (40.6-48.2Gy) for radiation alone and 44.4Gy(41.6-47.4Gy) for two doses GBE plus radiation, showing no effect of GBE on acute radiation skin damage. The numbers of regenerating jejunal crypts per circumference were also almost the same for each radiation dose level(p=0.57-0.94), and the mean lethal doses($D_o$) were 1.800y(1.57-2.09Gy) for radiation alone and 1.88Gy(1.65-2.18Gy) for two doses GBE plus radiation, indicating no effect of GBE on jejunal crypt cell survival after radiation. Conclusion : GBE doesn't increase acute normal tissue radiation reaction in this model system. As GBE was verified to enhance radiation effect on tumor, high therapeutic gain is expected when GBE is combined with radiation therapy.

• Journal of Animal Environmental Science
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• v.17 no.1
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• pp.49-54
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• 2011

Animal manure is produced annually 43.7 million tonnes in Korea. Among them, about 85.6 % are used as compost or liquid fertilizer to the agricultural land. The animal manure can be effectively utilized by mixing with organic byproducts that result in generation of biogas from anaerobic co-digestion process. This study aimed to optimize the content of total solid materials (TS) and determine the effect of organic byproduct on the co-digestion process. Prior to the byproduct treatments, determination of proper content of TS was conducted by controlling at 5 or 10 %. For the byproduct treatments, swine manure without adding the byproduct was used for control treatment, and swine manure mixed with either corn silage or kitchen waste was used for other treatments. Volume of biomethane ($CH_4$) generated from digested materials was quantified before and after byproduct treatments. In result, a 1.4-fold higher biomethane, about 0.556 L/$L{\cdot}d$, was produced when the content of TS was controlled at 10 %, compared at 5 %, about 0.389 L/$L{\cdot}d$. When the swine manure was mixed with the corn silage or kitchen waste, a two-fold higher biomethane was produced, about 1.theand 1.0heL/$L{\cdot}d$, respectively, compared to the control treatment. Biogas production from organic dry matter (odm) was a3, 362eand 2h6 L/kg odm${\cdot}$d for control, corn silage, and kitchen waste treatment, respectively. The lower biogas production in the treatment of kitchen waste than that of corn silage is associated with its relatively high odm contents. The methane concentration during the whole process ranged from 40 at the beginning to 70 % at the end of process for both the control and kitchen waste treatments, and ranged from 52 to 70 % for the corn silage treatment. Hydrogen sulfide ($H_2S$) concentration ranged between 350 and 500 ppm. All the integrated results indicate that addition of organic byproduct into animal manure can double the generation of biogas from anaerobic fermentation process.