• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.22 no.1
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• pp.108-119
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• 2009

Objectives : This study was carried out to investigate the effects of Samhwangseje(SHSJ) on anti-Inflammation in Raw 264.7 cell. Methods : The effects of SHSJ on anti-Inflammation were measured by the cytotoxicity of Raw 264.7 cell, the inhibition for NO, TNF-$\alpha$, $PGE_{2}$, iNOS and COX-2, the blocking NF-${\kappa}B$ into nucleus. Results : 1. All concentrations of SHSJ had no cytotoxicity in Raw 264.7 cell. 2. All concentrations of SHSJ inhibited the production of NO in the Raw 264.7 cell stimulated with LPS. 3. All concentrations of SHSJ did not inhibit the production of TNF-$\alpha$ in the Raw 264.7 cell stimulated with LPS. 4. All concentrations of SHSJ inhibited the production of $PGE_{2}$ in the Raw 264.7 cell stimulated with LPS. 5. All concentrations of SHSJ did not inhibit the expression of COX-2 but concentrations of 50 ${\mu}g/ml$, 100 ${\mu}g/ml$ SHSJ inhibited iNOS expression in the Raw 264.7 cell stimulated with LPS. 6. Concentrations of 50 ${\mu}g/ml$, 100 ${\mu}g/ml$ SHSJ had the effect of blocking NF-${\kappa}B$ into nucleus in LPS-induced macrophage Raw 264.7 cell.

• Korean Journal of Medicinal Crop Science
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• v.13 no.5
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• pp.227-232
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• 2005

The antioxidant effect of methanol extract (ME) and water extract (WE) from Clematis trichotoma was evaluated as primary study to scavenge stable 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH), inhibited iron-induce lipid peroxidation in linoleic acid emulsion, peroxidation of liposome induced by $Fe^{3+}/H_2O_2/ascorbie$ acid, and on $Fe^{2+}/H_2O_2$ induced the mitochondrial lipid peroxidation. In secondary study, five flavonoids as luteolin (1), quercetin (2), apigenin (3), hirsutrin (4), kaempferol-3-O-glucoside were isolated (5). Among them, compounds 1 and 2 showed good activities in all the model systems. Compound 3 exhibited moderate antioxidant activities in both radical scavenging and these lipid peroxidation systems tested. Compound 4 showed significant inhibitions in liposome peroxidation and compound 5 displayed weak inhibition in all four tested systems. All the results presented herein indicate that products of C. trichotoma maybe useful in inhibiting membrane lipid peroxidation and preventing free radical-linked diseases.

• Tribology and Lubricants
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• v.16 no.6
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• pp.477-483
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• 2000

Rolling contact fatigue (RCF) tests were performed for two kinds of commercial silicon nitride balls using 4-Ball rolling contact fatigue life tester under EHL condition (Λ=8.9) and boundary lubrication condition (Λ=0.2). All the test balls were finished up to the dimensional accuracy of Grade 5 defined in KS B 2001 (Steel Balls for Ball Bearings) with a size of 8.731 mm. RCF tests were then conducted under the initial theoretical maximum contact stress 6.63 GPa and the spindle speed 10,000 rpm. All the test balls were not failed until 3.75 $\times$ 107 contact cycles and wear tracks of test balls were not conspicuous under EHL condition (Λ= 8.9). In the operations of low lambda regime (Λ= 0.2), all the test balls were surface damaged and high rolling wear resistance was achievable in fully densified using MgO 1 wt% and HIPed balls. Rolling wear of silicon nitride balls under boundary lubrication condition depend mainly on grain size and intergranular phase content of silicon nitride balls.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.10a
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• pp.230-234
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• 1995

The loss of offsite power test was successfully performed on YGN 4 to demonstrate that the reactor can be shutdown and the RCS can be maintained in a hot standby condition following a loss of all offsite Alternating Current (AC) power. Following the loss of main generator and all offsite AC power, the ensile emergency diesel generators were automatically started and the plant was stabilized via natural circulation. Plant conditions were maintained in hot standby for at least 30 minutes before offsite power was restored. Thus, the capability of equipment, controls and instrumentation necessary to remove decay heat from the core using only ensile emergency power was demonstrated, thereby satisfying all objectives and acceptance criteria of the test.

• Korean Management Science Review
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• v.33 no.4
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• pp.33-49
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• 2016

The market of platform business is typically served by a few dominant players, presenting "winner-takes-all" phenomenon. This study aims to find service characteristics leading to the phenomenon. Six different service-characteristics were considered : Same-side network effect, cross-side network effects, entry barrier, multi-homing cost, switching cost, and heterogeneity of preference. To assess the degree of concentration of market share, HHI (Herfindahl-Hirschman Index) is calculated for top three major players. Based on the HHI value, 10 most eminent platform businesses are classified into three different segments and each segment is characterized with key factors. The results from this study provide some insight into the strategic management of platform business.

• Environmental Analysis Health and Toxicology
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• v.16 no.4
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• pp.143-151
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• 2001

Six rivers were selected as preliminary screening sites to determine the test conditions of Microtox in assessing the toxicity of the sediment. In addition, a pH range of 6.0∼6.5 was established in testing pore water, aqueous extracts and organic extracts. Each extractable fraction of sediment showed different toxicities. Therefore, in order to properly examine the toxicity in the sediment, all extractable fractions of sediment samples needed to be tested with Microtox. Thus, sediment samples were additionally collected from at least 4 secondary sites within 50∼100ｍ area of the primary sampling site to reduce any variation or deviation in toxicity assessment. From all sediment toxicity data that was collected from this study, it was concluded that the Keumho river was the most polluted with the highest sediment toxicity of all the rivers analyzed and needed further detailed research on its pollution problem.

• The Korean Journal of Pharmacology
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• v.1 no.1 s.1
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• pp.7-16
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• 1965

Glycyrrhizin, an active constituent of Glycyrrhiza, was chemically extracted and its hypocholesterolemic activities were studied in rats. Following were the results: 1. The Sprague Dowley rats fed with the standard diet were divided into 4 groups, $50{\sim}60$ in each, and glycyrrhizin was given in doses of 0 (control), 0.5, 1.0 and 2.0mg per 100gm body weight daily for 10, 20, 30, and 60 days. Glycyrrhizin showed more or less the hypocholesterolemic activities in all animals. All of the animal groups to which 1. 0mg and 2.0mg of glycyrrhizin were given died before 60 days, while no mortality cases was noted in the group to which 0.5mg of glycyrrhizin was given. 2. Cholesterol administration induced hypercholesterolemia in all experimental animals, however, simultaneous administration of cholesterol with 0.5mg of glycyrrhizin suppressed the rise of the total serum cholesterol levels. The former group did not survive until 56 days, while the latter did. 3. Glycyrrhizin also Suppressed the cholesterol biosynthesis and incorporation of cholesterol in the liver tissues. 4. Glycyrrhizin induced the increase of the fecal excretion of the sterol compounds.

• Communications of the Korean Mathematical Society
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• v.20 no.4
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• pp.671-683
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• 2005

The set of all $m\;{\times}\;n$ matrices with entries in $\mathbb{Z}_+$ is de­noted by $\mathbb{M}{m{\times}n}(\mathbb{Z}_+)$. We say that a linear operator T on $\mathbb{M}{m{\times}n}(\mathbb{Z}_+)$ is a (U, V)-operator if there exist invertible matrices $U\;{\in}\; \mathbb{M}{m{\times}n}(\mathbb{Z}_+)$ and $V\;{\in}\;\mathbb{M}{m{\times}n}(\mathbb{Z}_+)$ such that either T(X) = UXV for all X in $\mathbb{M}{m{\times}n}(\mathbb{Z}_+)$, or m = n and T(X) = $UX^{t}V$ for all X in $\mathbb{M}{m{\times}n}(\mathbb{Z}_+)$. In this paper we show that a linear operator T preserves the rank of matrices over the nonnegative integers if and only if T is a (U, V)­operator. We also obtain other characterizations of the linear operator that preserves rank of matrices over the nonnegative integers.

• Journal of Environmental Health Sciences
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• v.16 no.2
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• pp.41-45
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• 1990

This study was performed to analyze for the mineral water (Saeng Su) from 12 pure beverage Co. products, which was obtained during March to May in 1988. The results were as follows: 1. The analytical results of contaminant materials in all the samples were suitable for drinking water standard. The mean value of NH$_{3}$-N, NO$_{3}$-N, Cl-and KMnO$_{4}$ consumption were ND, 49mg/l, 1.08mg/l and 8.14mg/l, respectively. 2. Total bacterial counts were 3/cc in average and Coliforms was negative in all samples. 3. The analytical results of Heavy metals were not detected or detected in a small amount, and the contents were different from each company. The CN, Hg, P were not detected in all the samples and the mean value of Cu, Fe, Mn were 0.0087mg/l, 0.0303mg/l, 0.018mg/l, respectively and it's contents were low. 4. The mean value of Pb, Zn, Cr$^{+6}$, As and Cd were 0.016mg/l, 0.015mg/l, 0.0025mg/l. 0.0059mg/l and 0.0011mg/l respectively.

• Journal of Forest and Environmental Science
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• v.31 no.4
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• pp.255-260
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• 2015

Height growth models for Pinus thunbergii in Jeju Island were developed in this study using four widely used nonlinear growth models; Exponential, Modified Logistic, Chapman-Richards, and Weibull. All functions were found to be significant at the 1% level. Chapman-Richards model for height-DBH allometry and Weibull model for height-age allometry was chosen as the best model on the all validation. All the model curves showed the similar pattern. Additionally, there was no abnormal pattern when the previous studies were compared. Therefore, these models are highly expected to be used to estimate the tree height using DBH or age for Pinus thunbergii especially in Jeju Island.