• Journal of the East Asian Society of Dietary Life
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• v.17 no.6
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• pp.846-852
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• 2007

The objective of this study was to compare the physical and sensory characteristics of pork from Korean native black pigs ($78{\pm}7kg$, female) to the pork of crossbred black pigs ($115{\pm}5kg$, female), both of which were reared for the same period on Jeju Island. The Korean native black pig showed a lower $L^*$ value (lightness) and higher $a^*$-(redness) and $b^*$-values (yellowness) than the crossbred black pig. There were no statistically meaningful differences between the two pigs' loins, hams and bellies of the two breeds of pig in terms of water holding capacity, thawing loss, cooking loss, myofibrillar protein extract, and fragmentation index. The crossbred black pigs showed greater significant differences among the physical characteristics of each part, as compared to the Korean native black pigs. The cooked meat of the Korean native black pig had superior hardness to that of the crossbred black pig, whereas the raw meat had a lower hardness, chewiness, and shear force value. Finally, there was no significant difference between the two pigs in terms of palatability.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.4
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• pp.82-88
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• 2009

Video proxy server which is located near clients can store the frequently requested video data in storage space in order to minimize initial latency and network traffic significantly. However, due to the limited storage space in video proxy server, an appropriate video selection method is needed to store the videos which are frequently requested by users. Thus, we present a virtual caching technique to efficiently store the video in video proxy server. For this purpose, we employ a virtual memory in video poky server. If the video is requested by user, it is loaded in virtual memory first and then, delivered to the user. A video which is loaded in virtual memory is deleted or moved into the storage space of video poxy sewer depending on the request condition. In addition, virtual memory is divided into each segment area in order to store the segments efficiently and to avoid the fragmentation. The simulation results show that the proposed method performs better than other methods in terms of the block hit rate and the number of block deletion.

• Journal of Environmental Policy
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• v.13 no.3
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• pp.21-42
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• 2014

Abandoned roads, abandoned expressways included, cause a lot of problems such as contamination and environmental damages to underground water, fragmentation of wildlife habitats yet they are not appropriately maintained or managed because of jurisdictional conflicts and, often more importantly, insufficient budget of governments. The restoration of abandoned roads is known to benefit society and its constituents by providing better environment and higher living standards but the monetary value of the benefit is hard to measure because of non-marketability of the good that the restoration brings about. In this case, the contingent valuation method(CVM) is most powerful in evaluating non-marketable value of goods and hence it is used widely. We also used the CVM to value the benefit of restoration of abandoned expressways to find out: about 40% of total households are willing to contribute positive amount for restoration; better awareness of environmental issues leads to higher willingness-to-pay.

• International Journal of Oral Biology
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• v.41 no.3
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• pp.105-111
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• 2016

${\beta}-carotene$ is present in carrots, pumpkins, and sweet potatoes. It suppresses many types of cancers by regulating cellular proliferation and apoptosis through a variety of mechanisms. However, the effects of ${\beta}-carotene$ on oral cancer cells have not been clearly established. The main goal of this study was to investigate the effects of ${\beta}-carotene$ on cell growth and apoptosis in oral cancer cells. Our results demonstrate that treatment with ${\beta}-carotene$ induced inhibition of cell growth, and that the effect was dependent on ${\beta}-carotene$ treatment time and concentration in KB cells. Furthermore, treatment with ${\beta}-carotene$ induced nuclear condensation and fragmentation in KB cells. ${\beta}-carotene$ promoted proteolytic cleavage of procaspase-3, -7, -8 and -9 with associated increases in the concentration of cleaved caspase-3, -7, -8 and -9. In addition, the level of cleaved PARP was increased by ${\beta}-carotene$ treatment in KB cells. These results suggest that ${\beta}-carotene$ can suppress cell growth and induce apoptosis in KB human oral cancer cells, and that it may have potential usefulness in anti-cancer drug discovery efforts.

• International Journal of Oral Biology
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• v.36 no.3
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• pp.155-162
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• 2011

Eugenol (4-allyl-2-methoxyphenol) is a naturally occurring phenolic compound that is widely used in dentistry as a component of zinc oxide eugenol cement that is commonly applied to the mouth environment. Cisplatin is one of the most potent known anticancer agents and shows significant clinical activity against a variety of solid tumors. This study was undertaken to investigate the synergistic apoptotic effects of co-treatments with eugenol and cisplatin on human melanoma (G361) cells. To investigate whether this co-treatment efficiently reduces the viability of G361 cells compared with each single treatment, an MTT assay was conducted. The induction and augmentation of apoptosis were confirmed by DNA electrophoresis, Hoechst staining and an analysis of DNA hypoploidy. Western blot analysis and immunofluorescent staining were also performed to evaluate the expression levels and the translocation of apoptosis-related proteins following this co-treatment. Furthermore, proteasome activity and mitochondrial membrane potential (MMP) changes were also assayed. The results indicated that a co-treatment with eugenol and cisplatin induced multiple pathways and processes associated with an apoptotic response in G361 cells including nuclear condensation, DNA fragmentation, a reduction in MMP and proteasome activity, the increase and decrease of Bax and Bcl-2, a decreased DNA content, the release of cytochrome c into the cytosol, the translocation of AIF and DFF40 (CAD) into the nucleus, and the activation of caspase-9, caspase-7, caspase-3, PARP and DFF45 (ICAD). In contrast, separate treatments of 300 ${\mu}M$ eugenol or 3 ${\mu}M$ cisplatin for 24 h did not induce apoptosis. Our present data thus suggest that a combination therapy of eugenol and cisplatin is a potential treatment strategy for human melanoma.

• International Journal of Oral Biology
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• v.36 no.3
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• pp.135-141
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• 2011

Hertwig's epithelial root sheath (HERS) consists of bi-layered cells derived from the inner and outer dental epithelia and plays important roles in tooth root formation as well as in the maintenance and regeneration of periodontal tissues. With regards to the fate of HERS, and although previous reports have suggested that this entails the formation of epithelial rests of Malassez, apoptosis or an epithelial-mesenchymal transformation (EMT), it is unclear what changes occur in the epithelial cells in this structure. This study examined whether HERS cells undergo EMT using a keratin-14 (K14) cre:ROSA 26 transgenic reporter mouse. The K14 transgene is expressed by many epithelial tissues, including the oral epithelium and the enamel organ. A distinct K14 expression pattern was found in the continuous HERS bi-layer and the epithelial diaphragm were visualized by detecting the ${\beta}$-galactosidase (lacZ) activity in 1 week postnatal mice. The 2 and 4 week old mice showed a fragmented HERS with cell aggregation along the root surface. However, some of the lacZ-positive dissociated cells along the root surface were not positive for pan-cytokeratin. These results suggest that the K14 transgene is a valuable marker of HERS. In addition, the current data suggest that some of the HERS cells may lose their epithelial properties after fragmentation and subsequently undergo EMT.

• International Journal of Oral Biology
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• v.35 no.4
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• pp.215-220
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• 2010

Angelica decursiva has been used in Korean traditional medicine as an antitussive, an analgesic, an antipyretic and a cough remedy. However, its anti-cancer properties have not yet been well defined. In our current study, we report the cytotoxic activity and the mechanism of cell death induced by ethanol extracts of Angelica decursiva (EEAD) against the human oral cancer cell line, KB. Treatment of KB cells with EEAD induced apoptotic cell death in both a dose- and time-dependent manner as determined by MTT assay and DNA fragmentation. However, no cytotoxic effects of EEAD against human normal oral keratinocytes (HNOK) were evident. By western blot analysis, we found that apoptosis in KB cells is associated with a decrease in procaspase-7 and -9. In addition, the activation of caspase-7 was detectable in living KB cells by fluorescence microscopy. These results suggest that EEAD exhibits anti-cancer activity in KB cells via apoptosis and thus has potential as an anticancer agent in future drug development strategies.

• International Journal of Oral Biology
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• v.38 no.3
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• pp.101-110
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• 2013

We investigated the synergistic apoptotic effects of co-treatments with Chios gum mastic (CGM) and eugenol on G361 human melanoma cells. An MTT assay was conducted to investigate whether this co-treatment efficiently reduces the viability of G361 cells compared with each single treatment. The induction and augmentation of apoptosis were confirmed by DNA electrophoresis, Hoechst staining, and analyses of DNA hypoploidy. Western blot analysis and immunofluorescent staining were also performed to evaluate expression and translocation of apoptosis-related proteins following CGM and eugenol co-treatment. Proteasome activity and mitochondrial membrane potential (MMP) changes were also assayed.The results indicated that the co-treatment of CGM and eugenol induces multiple pathways and processes associated with an apoptotic response in G361 cells. These include nuclear condensation, DNA fragmentation, a reduction in MMP and proteasome activity, an increase of Bax and decrease of Bcl-2, a decreased DNA content, cytochrome c release into the cytosol, the translocation of AIF and DFF40 (CAD) into the nucleus, and the activation of caspase-9, caspase-7, caspase-3, PARP and DFF45 (ICAD). In contrast, separate treatments of $40{\mu}g/ml$ CGM or $300{\mu}M$ eugenol for 24 hours did not induce apoptosis. Our present data thus suggest that a combination therapy of CGM and eugenol is a potential treatment strategy for human melanoma.

• Journal of the Korean Ceramic Society
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• v.53 no.6
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• pp.641-646
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• 2016

The effects of water addition on $Y_2O_3$ coatings or thick films prepared by plasma suspension spray (SPS) have been investigated. Water addition in suspension media was found to be effective to control the color of a $Y_2O_3$ coating prepared by SPS. The color changed with water addition at the shortest stand-off distance of 50 mm even if samples had the same crystalline phase. Change was not correlated with fragmentation behavior of liquid suspension inside the plasma jet. Water content over 50 vol% was found to produce unmelted particles, indicating that water suppressed heat transfer to the particles. However, plasma jet temperature was not affected. Instead, the coating fabricated with water addition has higher oxygen and lower carbon content compared to these characteristics of the coating without water addition. This was attributed to the retarded complete evaporation of liquid media from the suspension droplet, resulting in inhibition of excessive heating and evaporation of the molten $Y_2O_3$ droplet. In this regard, crystalline phase development with respect to stand-off distance and water addition was discussed.

• The Journal of the Korean dental association
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• v.53 no.1
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• pp.47-56
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• 2015

Obstructive sleep apnea (OSA), most common respiratory disorder of sleep, is characterized by intermittent partial or complete occlusions of the upper airway due to loss of upper airway dilating muscle activity during sleep superimposed on a narrow upper airway. Termination of these events usually requires arousal from sleep and results in sleep fragmentation and hypoxemia, which leads to poor quality of sleep, excessive daytime sleepiness, reduced quality of life and numerous other serious health consequences Untreated OSAS can cause various problems such as hypertension, diabetes, stroke, cardiac disease, daytime sleepiness. Various treatments are available, including non-surgical treatment such as medication or modification of life style, surgical treatment, continuous positive airway pressure (CPAP) and oral appliance (OA). Oral appliance is known to be effective in mild to moderate OSA, also genioglossus muscle advancement (GA) or maxillomandibluar advancement (MMA) is a good option for OSA patients with muscular or skeletal problems. Although the prevalence of OSA is increasing, the proportion of the patient treated by dentist is still very law. Dentists need to understand the mechanism of OSA and develop abilities to treat OSA patients with dental problems. The purpose of this paper is to give a brief overview about OSA and the dentist's role in OSA patients.