• Fire Science and Engineering
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• v.29 no.2
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• pp.73-78
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• 2015

Fire in the risk management subject belongs to high risk disaster which accompanies personnel and materiel loss. So, management of disaster and safety is required to include fire prevention activities, fire risk prediction and investment of safety management expense. Combustion toxicity is required by gas toxicity test (KS F 2271), to minimize human damage. In this study, gas toxicity test were experimented with regard to urethane sample (Depth 5~25 mm) to obtain basic data. Fire effluent exposing to experimental animal were analyzed by FT-IR (Fourier transform infrared spectroscopy). Combustion toxicity index Lethal Fractional Effective Dose ($L_{FED}$) of ISO 13344 was calculated. According to the result of calculating Lethal Concentration 50% ($LC_{50}$) based on $L_{FED}$, $LC_{50}$ of urethane sample containing certain level of fire load is confirmed as $118{\sim}129g/m^3$. Through this study, applicability of this method was confirmed for fire risk assessment. This method can provide information to predict human damage by toxicity combustion gas for securing safety.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.71-71
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• 2018

Sea pollution accidents have been occurred due to the increase of marine ship traffic. Oil spill from the hull hole induced by tanker collision results in the huge sea pollution. Proper and prompt reaction on such oil spill disaster is needed to minimize the damage. Thru-hull emergency wood plug is typically used to manually close small holes, while it is required to develop some mechanical devices for closing large holes in the hull due to huge fluid pressure. Accurate estimation of oil discharge and velocity from such holes are important to develop proper device to control hull hole damage. High resolution CFD modeling investigation on the configurations of hull hole of 7.5 m initial depth and 30 cm diameter, which was observed in the oil spill accident of the Hebei Sprit off the west coast of Korea in 2007, has been carried out to compute the oil spill velocity distribution in terms of flow depth. Friction loss due to the viscous flow and the discharge coefficient of crude oil with specific gravity SG = 0.85 and viscosity of $4-12cP(mPa{\cdot}s)$ at the temperature of $20^{\circ}C-100^{\circ}C$ are presented in terms of Reynolds number based on the results of high-resolution CFD modeling.

• International Journal of Highway Engineering
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• v.10 no.3
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• pp.149-158
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• 2008

This study was estimated on performance of deicers, corrosion inhibitors and low corrodible deicer used for removal of snow or ice on the road and on influence on structure. The weight loss rate after freezing and thawing of low corrodible deicer is lower than one of deicer, corrosion inhibitors and these combination. Relative dynamic elastic modulus of all except water, low corrodible deicer and NaCl+JF-1004 was radically reduced after freezing and thawing 150 cycles. And concretes after freezing and thawing were showed severe surface damage. It was found that individual use of low corrodible deicer and corrosion inhibitors had a problem of field application because of lack of early ice melting effect and considerably low durability. Products combined with NaCl was showed rapid weight loss by metal corrosion. Therefore, It will need to circumspectly select combination of deicers having low effect on concrete pavement and bridge if possible.

• Restorative Dentistry and Endodontics
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• v.18 no.1
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• pp.1-26
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• 1993

The purpose of this study was to investigate the effect of acid etching on the surface appearance and fracture toughness of five glass ionomer cements. Five kinds of commercially available glass ionomer cements including chemical curing filling type, chemical curing lining type, chemical curing metal reinforced type, light curing tilling type and light curing lining type were used for this study. The specimens for SEM study were fabricated by treating each glass ionomer cement with either visible light curing or self curing after being inserted into a rubber mold (diameter 4mm, depth 1mm). Some of the specimens were etched with 37% phosphoric acid for 0, 15, 30, 60, go seconds, at 5 minutes, 1 hour and 1 day after mixing of powder and liquid. Unetched ones comprised the control group and the others were the experimental groups. The surface texture was examined by using scanning electron microscope at 20 kV. (S-2300, Hitachi Co., Japan). The specimens for fracture toughness were fabricated by curing of each glass ionomer cement previously inserted into a metal mold for the single edge notch specimen according to the ASTME399. They were subjected to a three-point bend test after etching for 0, 30, 60, and 90 seconds at 5 minutes-, 1 hour-and 1 day-lapse after the fabrication of the specimens. The plane strain fracture toughness ($K_{IC}$) was determined by three-point bend test which was conducted with cross-head speed of 0.5 mm/min using Instron universal testing machine (Model No. 1122) following seven days storage of the etched specimens under $37^{\circ}C$, 100% humidity condition. Following conclusions were drawn. 1. In unetched control group, crack was present, but the surface was generally smooth. 2. Deterioration of the surface appearance such as serious dissolving of gel matrix and loss of glass particles occured as the etching time was increased beyond 15 s following Immediate etching of chemical curing type of glass ionomer cements. 3. Etching after 1 h, and 1 d reduced surface damage, 15 s, and 30s etch gave rough surface appearance without loss of glass particle of chemical curing type of glass ionomer cements. 4. Light curing type glass ionomer cement was etched by acid, but there was no difference in surface appearances according to various waiting periods. 5. It was found that the value of plane stram fracture toughness of glass ionomer cements was highest in the light curing filling type as $1.79\;MNm^{-1.5}$ followed by the light curing lining type, chemical curing metal reinforced type, chemical curing filling type and chemical curing lining type. 6. The value of plane stram fracture toughness of the chemical curing lining type glass ionomer cement etched after 5 minutes was lower than those of the cement etched after 1 hour or day or unetched (P < 0.05). 7. Light curing glass ionomer cement showed Irregular fractured surface and chemical curing cement showed smooth fractured surface.

• Journal of Life Science
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• v.32 no.6
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• pp.482-490
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• 2022

Sarcopenia, a geriatric and multifactorial syndrome characterized by progressive systemic skeletal muscle disorder, may be associated with many comorbidities. Sarcopenia caused by a decrease in muscle mass and muscle strength is accompanied by the aggravation of various pathological conditions, and as life expectancy increases, its prevalence will continue to increase in the future. During the aging process, chronic oxidative stress and increased inflammatory responses act as major contributors to skeletal muscle loss. In addition, disruption of autophagy and apoptosis signals associated with dysfunction of mitochondria, which are essential for energy metabolism, accelerates the loss of muscle proteins. The pharmacological effect of cordycepin, a major physiologically active substance in the genus Cordyceps, which has been widely used for the prevention and treatment of various diseases for a long time, is directly related to its antioxidant and anti-inflammatory actions. In this review, we present the correlation between apoptosis, autophagy, protein catabolism, and satellite cell activity important for muscle regeneration using cordycepin for the prevention and treatment of sarcopenia. Although there have been few studies so far on the use of cordycepin for sarcopenia, previous studies suggest that cordycepin may contribute to inhibiting the age-related weakening of mitochondrial function and blocking the breakdown of muscle proteins. In addition, the protective effect of cordycepin on muscle cell damage is considered to be closely related to its antioxidant and anti-inflammatory activities. Therefore, it is considered that more continuous basic research is needed, focusing on the molecular biological mechanism of cordycepin, which is involved in the anti-aging of muscle cells.

• Journal of Veterinary Clinics
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• v.26 no.5
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• pp.445-449
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• 2009

For human organ transplantations, histidine-tryptophan-ketoglutarate solution (HTKS) and University of Wisconsin solution (UWS) have been shown to engender similar outcomes as gold standard cold preservation solutions ($4^{\circ}C$). To select the effective preservation solution for cold storage of kidney xenografts in miniature pig, which could be a potential source animal of bio-organs, this study compared early histopathological outcomes of cold preservation injury using HTKS and UWS. Twelve miniature pigs weighing 25.6 to 34.7 kg were divided into two groups (n = 6 per group), UWS group and HTKS group. The kidneys in each group were harvested, cold flushed, and preserved for 0, 24, 48, and 72 hrs at $4^{\circ}C$ with UWS or HTKS, respectively. Histolopathological examinations were assessed on kidney biopsy specimens, taken after each cold storage. The degree of renal injury was scored using 5 different criteria (pyknotic nuclei, disruption of cytoplasm, detachment of epithelium, loss of microvilli, tubular necrosis and loss of glomerular tufts) of the cellular components of the tissue. The degree of kidney damage was increased with prolonged cold ischemia time. UWS and HTKS have at least similar efficacy in kidney preservation within 24 hrs cold preservation time. However, in HTKS group cold-induced injury started to be observed more than in UWS group after 48 hrs of cold storage. In conclusion, UWS and HTKS were equally effective for cold preservation of miniature pig kidney in early preservation times; however, UWS may be more effective at longer preservation times as compared to HTKS.

• Journal of the Korean Geotechnical Society
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• v.38 no.6
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• pp.5-16
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• 2022

In the case of domestic seismic design, deformation of structures and ground is reviewed through undrained condition analysis and applied to design and maintenance. However, when the ground undergoes dissipation after liquefaction due to a dynamic load such as an earthquake, additional displacement occurs and greater damage occurs. Therefore, it is necessary to additionally analyze the drained conditions, It is necessary to grasp the exact ground behavior such as calculating and reviewing the amount of subsidence of the ground that has undergone the loss process after an earthquake and apply it to design and maintenance together. Therefore, in this study, numerical analysis was performed assuming undrained and drained conditions by dividing pure sandy soil into loose soil with Dr=30% and high-density soil with Dr=70%. In particular, when a dynamic load such as an earthquake is applied, considering the drained conditions of the ground, the settlement amount and the pore water pressure ratio of loose and dense ground are compared, This study focused on comparative analysis of settlement amount and pore water pressure ratio in the process of ground loss after an earthquake. As a result, the amount of subsidence during the dissipation process was 30 to 60 times greater than that of the earthquake.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.4
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• pp.10-27
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• 2014

HAZUS-MH is a GIS-based computer program that estimates potential losses from multi-hazard phenomena: earthquakes, floods and hurricanes. With respect to seismic disaster, characteristics of a hypothetical or actual earthquake are entered into HAZUS. Then HAZUS estimates the intensity of ground shaking and calculates the correspondent losses. In this study, HAZUS was used as a part of the preparations of the future seismic events at a coastal plant facility area. To reliably characterize the target facility area, many geotechnical characteristics data were synthesized from the existing site investigation reports. And the buildings and facilities were sorted by analyzing their material and structural characteristics. In particular, the study area was divided into 17 blocks taking into account the situation of both land development and facility distribution. The ground conditions of blocks were categorized according to the site classification scheme for earthquake-resistant design. Moreover, seismic fragility curves of a main facilities were derived based on the numerical modeling and were incorporated into the database in HAZUS. The results estimated in the study area using HAZUS showed various seismic damage and loss potentials depending on site conditions and structural categories. This case study verified the usefulness of the HAZUS for estimating earthquake losses in coastal facility areas.

• Journal of Ginseng Research
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• v.40 no.3
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• pp.260-268
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• 2016

Background: During the aging process, skin shows visible changes, characterized by a loss of elasticity and the appearance of wrinkles due to reduced collagen production and decreased elasticity of elastin fibers. Panax ginseng Meyer has been used as a traditional medicine for various diseases due to its wide range of biological activities including skin protective effects. Ginsenosides are the main components responsible for the biological activities of ginseng. However, the protective activities of an enzymatic preparation of red ginseng against human skin aging have not been investigated. Methods: The efficacy of an enzyme-treated powder complex of red ginseng (BG11001) in preventing human skin aging was evaluated by oral administration to 78 randomized individuals. All patients were requested to take three daily capsules containing either 750 mg of BG11001 or a placebo vehicle for 24 wk; at the end of the testing period, skin roughness, elasticity, and skin water content were measured. Results: BG11001 significantly reduced the average roughness of eye wrinkles and the Global Photo Damage Score compared with the placebo, although there were no significant differences in arithmetic roughness average between the groups. In addition, gross elasticity and net elasticity values increased, and transepidermal water loss level decreased, indicating improved skin elasticity and moisture content. Conclusion: In conclusion, enzyme-treated red ginseng extract significantly improved eye wrinkle roughness, skin elasticity, and moisture content. Moreover, enzyme-treated red ginseng extract would be useful substance as a bio-health skin care product.

• Korean Journal of Otorhinolaryngology-Head and Neck Surgery
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• v.61 no.11
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• pp.573-579
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• 2018

Background and Objectives Cochlear dead region (CDR) is a region in the cochlear where hearing loss has occurred due to damage to the inner hair cells and/or neurons. Recently, a subjective test involving a pure-tone test in the presence of threshold-equalizing noise (TEN) was introduced to identify CDR. However, for uncooperative patients, such a subjective method would be unsuitable and objective methods would be needed instead to detect CDR. The acoustic change complex (ACC) is an evoked potential elicited by changes in the ongoing sound. In this study, we developed an objective method of identifying CDR by combining ACC response with a TEN test, namely the TEN-ACC test, and investigated its feasibility in normal-hearing listeners. Subjects and Method Ten normal-hearing subjects participated in this study. All subjects underwent both behavioral TEN test and electrophysiological TEN-ACC test. The stimuli for the TEN-ACC test consisted of TEN and embedded pure tones with different frequencies/signals to noise ratios (SNRs). To identify the thresholds, the range SNR of stimulation was varied from 0 to 20 dB, in stages of 4 dB. Results The ACC responses of all subjects who participated in this study were well elicited by stimuli developed for the TEN-ACC test. We confirm that the pure-tones embedded in TEN elicited the objective ACC response. Conclusion The results of this study suggest that the novel TEN-ACC test can be applied to evoke ACC in normal-hearing listeners. Future research should incorporate hearing-impaired listeners to determine the feasibility of the TEN-ACC test as an objective method to identify CDR.