• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.3
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• pp.9-20
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• 1999

A method is proposed to estimate the joint damages of a steel structure from modal data using the neural networks technique. The beam-to-column connection in a steel frame structure is represented by a zero-length rotational spring of the end of the beam element, and the connection fixity factor is defined based on the rotational stiffness so that the factor may be in the range 0~1.0. Then, the severity of joint damage is defined as the reduction ratio of the connection fixity factor. Several advanced techniques are employed to develop the robust damage identification technique using neural networks. The concept of the substructural indentification is used for the localized damage assessment in the large structure. The noise-injection learning algorithm is used to reduce the effects of the noise in the modal data. The data perturbation scheme is also employed to assess the confidence in the estimated damages based on a few sets of actual measurement data. The feasibility of the proposed method is examined through a numerical simulation study on a 2-bay 10-story structure and an experimental study on a 2-story structure. It has been found that the joint damages can be reasonably estimated even for the case where the measured modal vectors are limited to a localized substructure and the data are severely corrupted with noise.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.261-261
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• 1994

Bovine milk xanthine oxidase (E.C.1.1.3.22, XO) purchased from Sigma Chemical Co. had the three protein fragments below 150 kDa on 7.5％ SDS-PAGE, which did not show enzyme activity. To remove these fragments, the enzyme preparation was further purified through Sephadex G-200 column chromatography. Two peaks exhibiting enzymatic activity were separated very closely to the void volume, which were revealed as two different enzyme forms, dimeric and monomeric, confirmed by activity staining on native PAGE. Anti sera-against each of the two enzyme forms were raised by subcutaneous injection at multiple sites on the back of rabbits during 4 weeks. On the immunodiffusion test, it was found that both of the antisera of the two forms could react with each other, which implied that their epitopes were identical In the Western blot analysis of mouse liver cytosol fraction, it was found that rabbit anti-XO antibody bound well with the protein band of monomeric mouse liver XO of about 150kDa. Based on this result, mouse liver cDNA 1 ibrary was screened by in situ hybridizat ion wi th rabbi t anti -XO antibody as probe. Through the immunological screening, recombinant phages giving positive signal by the production of XO were selected and further purified. To validate these clones, purified phages were lysogenized in E. coli Y1089 and their lysates were analysed for enzyme activity and immunoreactivity, It was verified that lysates of the purified recombinant phage lysogens exhibited the enzymatic activity as well as bound wi th XO antibody, when induced by IPTG. The above results assert that selected recombinant phage carries mouse liver XO gene.

• Journal of Soil and Groundwater Environment
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• v.20 no.4
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• pp.41-50
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• 2015

Open-loop groundwater heat pump (GWHP) system generally has benefits such as a higher coefficient of performance (COP), lower initial cost, and flexible system size. The hydrogeological conditions in Korea have the potential to facilitate the use of the GWHP system because a large number of monitoring wells show stable groundwater temperatures, shallow water levels, and high well yields. However, few studies have been performed in Korea regarding the GWHP system and the most studies among them dealt with Standing Column Well (SCW). Because the properties of the aquifer have an influence on designing open-loop systems, it is necessary to perform studies on various hydrogeological settings. In this study, the hydrogeological and thermal properties were estimated through various tests in the riverside alluvial layer where a GWHP system was installed. Under different groundwater flow velocities and pumping and injection rates, a sensitivity analysis was performed to evaluate the effect of such properties on the design of open-loop systems. The results showed that hydraulic conductivity and thermal dispersivity of the aquifer are the most sensitive parameters in terms of performance and environmental aspects, and sensitivities of the properties depend on conditions.

• Geomechanics and Engineering
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• v.33 no.2
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• pp.141-154
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• 2023

This study investigated the effect of water retention characteristics between aged and fresh Municipal Solid Waste (MSW) on the stability of the landfill. A series of transient numerical modeling for the slope of an MSW landfill was performed considering the variation of water retention characteristics due to leachate circulation. Four different scenarios were considered in this analysis depending on how to obtain hydraulic conductivity and the aging degree of materials. Unsaturated hydraulic properties of the MSW used for the modeling were evaluated through modified hanging column tests. Different water retention properties and various landfill conditions, such as subgrade stiffness, leachate injection frequency, and gas and leachate collection system, were considered to investigate the pore water distribution and slope stability. The stability analyses related to the factor of safety showed that unsaturated properties under those varied conditions significantly impacted the slope stability, where the factor of safety decreased, ranging between 9.4 and 22%. The aged materials resulted in a higher factor of safety than fresh materials; however, after 1000 days, the factor of safety decreased by around 10.6% due to pore pressure buildup. The analysis results indicated that using fresh materials yielded higher factor of safety values. The landfill subgrade was found to have a significant impact on the factor of safety, which resulted in an average of 34% lower factor of safety in soft subgrades. The results also revealed that a failed leachate collection system (e.g., clogging) could result in landfill failure (factor of safety < 1) after around 298 days, while the leachate recirculation frequency has no critical impact on stability. In addition, the accumulation of gas pressure within the waste body resulted in factor of safety reductions as high as 24%. It is essential to consider factors related to the unsaturated hydraulic properties in designing a landfill to prevent landfill instability.

• BMB Reports
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• v.33 no.2
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• pp.112-119
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• 2000

Three kinds of serine protease inhibitors, members of the Bowman-Birk trypsin inhibitor, were purified from Dolichos lablab seeds and named Dolichos protease inhibitor 1, 2 and 3 (DI-1, DI-2 and DI-3), respectively. Each inhibitor showed a single band with gel mobility at around 15.9, 12.1 and 14.6 kDa on 20% SDS-PAGE under reducing conditions. To characterize inhibitory specificity, the inhibition constant (Ki) for these inhibitors was measured against several known serine proteases. All three Dolichos protease inhibitors (DI-1, DI-2 and DI-3) inhibited the activity of trypsin and plasmin, but had no effect on thrombin and kallikrein (either for human plasma kallikrein or for porcine pancreas kallikrein). DI-1 inhibited chymotrypsin most effectively (Ki = $3.6{\times}10^{-9}\;M$), while DI-2 displayed inhibitory activity for porcine pancreatic elastase (Ki = $6.2{\times}10^{-8}\;M$). Pre-treatment of the 33 mg/kg of DI-mixture (active fractions from $C_{18}$ open column chromatography that included DI-1, DI-2 and DI-3) inhibited the induction of pseudomonal elastase-induced septic hypotension and prevented an increase in bradykinin generation in pseudomonal elastase-treated guinea pig plasma. Also, the increase of kallikrein activity, by injection of pseudomonal elastase, was inhibited by the pretreatment of the DI-mixture in a guinea pig. Since the DI-mixture had no inhibitory effect on kallikrein activity when Z-Phe-Arg-MCA was used as a substrate in vitro, its inhibitory activity in the pseudomonal elastase-induced septic hypotension model might not be due to a direct inhibition of plasma kallikrein in the activation cascade of the Hageman factor and prekallikrein system. These results suggest that the Dolichos DI-mixture might be used as an inhibitor in pathogenic bacterial protease-induced septic shock.

• Bulletin of the Korean Chemical Society
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• v.24 no.5
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• pp.559-565
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• 2003

An analytical method the determination of benzo(a)pyrene (BaP) and its hydroxylated metabolites, 1-hydroxybenzo(a)pyrene (1-OHBaP), 3-hydroxybenzo(a)pyrene (3-OHBaP), benzo(a)pyrene-4,5-dihydrodiol (4,5-diolBaP) and benzo(a)pyrene-7,8-dihydrodiol (7,8-diolBaP), in rat urine and plasma has been developed by HPLC/FLD and GC/MS. The derivatization with alkyl iodide was employed to improve the resolution and the detection of two mono hydroxylated metabolites, 1-OHBaP and 3-OHBaP, in LC and GC. BaP and its four metabolites in spiked urine were successfully separated by gradient elution on reverse phase ODS $C_{18}$ column (4.6 mm I.D., 100 mm length, particle size 5 ㎛) using a binary mixture of MeOH/H₂O (85/15, v/v) as mobile phase after ethylation at 90 ℃ for 10 min. The extraction recoveries of BaP and its metabolites in spiked samples with liquid-liquid extraction, which was better than solid phase extraction, were in the range of 90.3- 101.6% in n-hexane for urine and 95.7-106.3% in acetone for plasma, respectively. The calibration curves has shown good linearity with the correlation coefficients (R²) varying from 0.992 to 1.000 for urine and from 0.996 to 1.000 for plasma, respectively. The detection limits of all analytes were obtained in the range of 0.01-0.1 ng/mL for urine and 0.1-0.4 ng/mL for plasma, respectively. The metabolites of BaP were excreted as mono hydroxy and dihydrodiol forms after intraperitoneal injection of 20 mg/kg of BaP to rats. The total amounts of BaP and four metabolites excreted in dosed rat urine were 3.79 ng over the 0-96 hr period from adminstration and the excretional recovery was less than 0.065% of the injection amounts of BaP. The proposed method was successfully applied to the determination of BaP and its hydroxylated metabolites in rat urine and plasma for the pharmacokinetic studies.

• Analytical Science and Technology
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• v.8 no.2
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• pp.215-220
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• 1995

A simple, efficient and sensitive method was described for the simultaneous determination of catecholamine, indoleamine and related metabolites from the homogenates of the rat brain striatum by HPLC-ECD. The optimum mobile phase on a reverse phase $C_{18}$ column was 35mM sodium acetate buffer(included 10mM citric acid, 0.13mM $Na_4EDTA$, 0.58mM SOS, pH3-4):MeOH=85:15. The column temperature was $30^{\circ}C$. Dopamine(DA), 3, 4-dihydroxyphenyl acetic acid(DOPAC), homovanilic acid(HVA), 5-hydroxyindole acetic acid(5-HIAA), serotonin(5-HT) and noradrenaline(NA) could be separated and analysed to very small amount. The detection limits of this method were 2~10pg per injection for all components. The effects of age and sex of rat on the contents of the catecholamines and their metabolites in rat brain striatum were studied. The levels of DA and 5-HT contents of the 7 week old female rats were higher than those of the 7 week old male rats. As the age of rat increases, the contents of DOPAC increased significantly.

• Microbiology and Biotechnology Letters
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• v.31 no.4
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• pp.377-382
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• 2003

Purification of methioninase resulted in a yield of 69%, and SDS-PAGE analysis of the purified product revealed a single band of approximately 43 kDa in molecular weight. in vitro experiments with cancer cells incubated in methionine-free media demonstrated an increase in $^{11}$ C-methionine uptake to 25.8$\pm$1.1% at 6 hr, 31.8$\pm$0.8% at 24 hr, and 62.2$\pm$0.6% at 48hr, compared to controls. Treatment of the cancer cells with purified methioninase showed no decrease in survival after a 2 hr incubation with 0.01 U/ml, but survival of RR1022 cells decreased 30% after 24 to 48 hr incubation. SKOV-3 cells showed a 5% and 14% decrease in survival with 0.1 and 1 U/ml methioninase after 24 hr. After 48hr survival decreased 15% and 24% with 0.1 and 1 U/ml methioninase. Measurements of $^{11}$ C-methionine uptake in RR1022 cells demonstrated no change at 2 hr, but a 13.7$\pm$4.7% and 40.7$\pm$2.6% increase in uptake at 24 and 48 hr, respectively. SKOV-3 cells also showed no change at 2 hr, but had a 17.7$\pm$7.2% and 38.9$\pm$4.9% increase in $^{11}$ C-methionine uptake after 24 hr and 48 hr treatment with methioninase, respectively. $^{11}$ C-methionine PET imaging revealed clear visualization of both the tumors and contralateral infectious lesions. Administration of rMET appeared to result in a slight increase in tumor:nontumor contrast on $^{11}$ C-methionine PET images. Injection of purified methioninase also produced PET images where tumor uptake was higher than that of infectious lesions.

• Journal of the Korea Furniture Society
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• v.21 no.4
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• pp.273-283
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• 2010

Structural larger timber have some weak points as like much longer drying time at lower MC(15%), a considerable check developing and the difficulty for the chemicals injection, so it is necessary to develop lighter structural size member for using the new Hanok, heavy timber construction, living necessaries, furniture and industrial goods. The developed skin timber can be a good raw material for those uses. Skin timber is a hollowed timber which be bored out of its considerable cross-sectional area. The intention of this study was the evaluation of compressive capacity of skin timber. Specially, skin timbers which have more than 200mm in sizes were used to analyze the compressive capacity. From the results of this study, the following conclusions have been made: 1. Though considerable inner parts were bored out, both pine skin timber and larch skin timber showed a good compressive capacity to that of non-bored solid timber. 2. According to ASTM, pine skin timber showed various failure types, but Splitting type, Brooming and end rolling type were main failure types for the larch skin timber. 3. Pine skin timber didn't show the significance between cylindrical shape and rectangular shape, but larch skin timber showed the significance between two shapes. Therefore, for the larch skin timber, cylindrical shape and rectangular shape should be used as a column uses and beam uses respectively. 4. Pine skin timber and larch skin timber didn't show the significance on the compressive capacity. There is not much difference of compressive capacity between them, so it can be possible to select on the user convenience.

• KSBB Journal
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• v.18 no.2
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• pp.100-106
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• 2003

An on-line frontal analysis HPLC system was developed to determine the unbound concentration of (S)-perillyl alcohol, an potential anti-cancer agent, in human serum albumin (HSA) solution, The analysis was performed on a Develosil 100 Diol 5 (10 cm x 4.6 mm I.D.) high-performance frontal analysis (HPFA) column. Sodium phosphate solution was used as the mobile phase (pH 7.4, ionic strength 0.17) at a flow rate of 1 $m\ell$/min. UV wavelength was set at 205 nm. A injection volume of 600${mu}ell$ was chosen to ensure the compound eluted formed a zonal peak with a plateau. By Scatchard analysis, it was found that the binding constant(K) and binding number(n) of (S)-perillyl alcohol to molecular HSA were 2.05 x $10^6$ [$M{-1}$], 0.00428, respectively.