• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.2
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• pp.81-93
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• 2007

Purpose: Adenoid cystic carcinoma (ACC) is a relatively rare tumor that arises in glandular tissues of the head and neck region and sometimes has a protracted clinical course with perineural invasion and delayed onset of distant lung metastasis. Treatment failure of salivary ACC is most often associated with perineural and hematogenous tumor spread. However, very little has been known about the cellular and molecular mechanisms of perineural invasion and hematogenous distant metastasis of parotid ACC. This study was designed to develop an orthotopic tumor model of parotid adenoid cystic carcinoma in athymic nude mice. Experimental Design: A melanoma cell line was injected into the parotid gland of athymic mice to determine whether such implantation was technically feasible. A parotid ACC cell line was then injected into the parotid gland or the subcutaneous tissue of athymic mice at various concentrations of tumor cells, and the mice were thereafter followed for development of tumor nodule. The tumors were examined histopathologically for perineural invasion or regional or distant lung metastasis. We used an oral squmous cell carcinoma cell line as control. Results: Implantation of tumor(melanoma) cell suspension into the parotid gland of nude mice was technically feasible and resulted in the formation of parotid tumors. A parotid ACC cell line, ACC3 showed no significantly higher tumorigenicity, but showed significantly higher lung metastatic potential in the parotid gland than in the subcutis. In contrast, mucosal squmous cell carcinoma cell line doesn’t show significantly higher lung metastatic potential in the parotid gland than in the subcutis. The ACC tumor established in the parotid gland seemed to demonstrate perineural invasion of facial nerve, needs further study. Conclusion: An orthotopic tumor model of salivary ACC in athymic nude mice was successfully developed that closely recapitulates the clinical situations of human salivary ACC. This model should facilitate the understanding of the cellular and molecular mechanisms of tumorigenisis and metastasis of salivary ACC and aid in the development of targeted molecular therapies of salivary ACC.

• The Journal of Natural Sciences
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• v.8 no.2
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• pp.153-158
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• 1996

The Number of the disputes originated from vegetable seeds in 1968-1970 under 'Seed and Seedling Law for Agricultural Product)' was 177.: Poor germination was the major one (26% of total disputes), followed by inferior seeds(24.3%), imported seeds(23.7%), and off-type plant(15.6%).During 1976-1995, under 'Administrative Law for Seed and Seedling' the number of disputes originated from vegetable seeds was 175.: 53 in radish, 19 in Chinese cabbage, and 17 in pepper. The type of dispute originated from radish seeds was premature bolting(26%), differences in sowing data(21%), poor purity(19%), micronutrient deficiency(9%), root cracking and branching(9%), poor germination(4%), and damage by disease(2%). In Chinese cabbage, micronutrient deficiency was the major one(27%), followed by poor germination(21%), incomplete head formation(16%), damage by disease(16%), poor purity(10%), and bolting(10%). In pepper, poor fruit setting was the major one(6%), followed by malformed fruits(5%), damage by disease(3%), purity(2%), and poor germination(1%).

• Proceedings of the Ginseng society Conference
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• 1984.09a
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• pp.153-158
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• 1984

From water extract of red ginseng, two new-type glucosides, $A:\;C_{12}H_{16}O_8\;and\;B:\;C_9H_{16}\;O_7,$ were isolated by fractionation with highly porous polymer ollowed by chromatography on silica gel in yields of 0.04 and $0.16\%,$ respectivley. The structures of A and B were elucidated by means of NMR and MS. Neither glucosides were detected in the extract of white ginseng and the mechanism of formation of A and B during the process of steaming will be discussed. The isolation and identification of saponins of corms (head of the root) of red ginseng are also reported.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.2
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• pp.254-269
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• 2004

Polysilicato-iron coagulant (PSI) is receiving attention in Japan as a substitute for aluminum-based coagulants. In the first part of this article, coagulation, sedimentation and filtration experiments were carried out using kaolin clay particles as the turbidizing material and four types of PSI with various molar ratios of polysilicic acid to ferric chloride (Si/Fe ratio). Results demonstrate that use of a PSI with a high Si/Fe ratio can cause a more dramatic decrease in treated water turbidity but a higher suction time ratio (STR) than when PACl is used. However, optimization by increasing the rapid agitation strength GR is found to greatly improve the STR. In addition, the series of filtration experiments verified that optimization of GR is greatly effective in controlling rapid increases in filter head loss, and also formation of a thin aging layer in the upper part of the filter bed by slow-start filtration is effective in improving filtered water turbidity over the entire filtration process. The second part of this article describes two innovative filtration techniques to increase the particle separation efficiency; (1) coagulant-coated filter medium by enhancing the electrical potential of the surface of the filter medium, and (2) coagulant dosing in influent by controlling the electrical potential of particles entering the filter layer. From the results of the various filtration experiments using a pilot plant, these two techniques were found to be very effective to reduce the effluent water turbidity from the start to the end of a filter run. Moreover, in the filtration experiments using these two methods simultaneously, higher removal efficiency of approximately 3-log (99.7%) was realized, resulting that the finished water turbidity was accordingly reduced to 0.004mg/L.

• Imaging Science in Dentistry
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• v.33 no.1
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• pp.5-14
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• 2003

Purpose: To observe the histologic pattern of healing in molar tooth extraction sockets of streptozotocin-induced diabetic rats following irradiation. Materials and Methods: Mature Sprague-Dawley rats were divided into three groups: control, diabetic, and diabetic-irradiated groups. Diabetes mellitus was induced by injecting streptozotocin. Control rats were injected with a citrate buffer only. After 5 days, the right maxillary first molar was extracted under general anesthesia from each of the rats. After the extraction, rats in the diabetic-irradiated group were irradiated with a single absorbed dose of 10 Gy to the head and neck region. The rats were killed at 1, 3, 7, 14, 21, and 28 days after treatment. Tissue sections were stained with hematoxylin-eosin and Masson's trichrome. Results: In the diabetic and diabetic-irradiated groups, the early healing process of the socket extraction was similar to the control group, but bone formation was delayed at 7 days after the treatment. In the diabetic-irradiated group, alveolar bone surrounding the extraction socket showed signs of necrosis at 3 days after treatment, and hemorrhage was observed in connective tissue within the extraction socket at 14 days after treatment. Conclusion: This experiment revealed that the healing process of the extraction socket was severely delayed and retarded by irradiation in the diabetic state.

• Journal of the Korea Society of Computer and Information
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• v.19 no.6
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• pp.49-59
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• 2014

Recently, wireless sensor networks(WSNs) are widely used for intrusion detection and ecology, environment, atmosphere, industry, traffic, fire monitoring. In this paper, an energy efficient clustering algorithm is proposed. The proposed algorithm forms clusters uniformly by selecting cluster head that optimally located based on receiving power. Besides, proposed algorithm can induce uniform energy consumption regardless of location of nodes by multi-hop transmission and MST formation with limited maximum depth. Through the above, proposed algorithm elongates network life time, reduces energy consumption of nodes and induces fair energy consumption compared to conventional LEACH and HEED. The results of simulation show that the proposed clustering algorithm elongates network life time through fair energy consumption.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.6
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• pp.529-539
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• 2008

Background and Purpose : Oral squamous cell carcinoma (OSCC) is one of the most aggressive tumors of the head and neck area. OSCC is known to preferentially metastasize via lymphatic system, and resulting cervical lymph node metastasis is the most reliable of treatment failure. But the biological mechanism of the regional nodal metastasis is not clear. So, we determined metastasis-related factors in orthotopic nude mouse models of OSCC. Experimental Design : Two cell lines-KB and YD-10B cells, established from human oral mucosal squamous cell carcinoma, were xenografted into the tissue space of athymic murine mouth floor. The mice were followed for tumor development and growth, the murine tumors were examined histopathologically for local invasion or regional or distant metastasis. Finally, we performed immunohistochemical assays with antiepithelial growth factor (EGF), EGF receptor (EGFR), phosphorylated EGFR (pEGFR), and anti-vascular endothelial growth factor (VEGF), VEGF receptor (VEGFR)-2, phosphorylated VEGFR-2/3 (pVEGFR-2/3) antibodies. We also determined the microvessel density. Results : Transplantation of human OSCC tumor cells into the mouth floor successfully resulted in the formation of orthotopic tumors. KB cell line showed significantly higher tumor proliferation and higher nodal metastatic potential than YD-10B cell line. Furthermore, immunohistochemical staining demonstrated higher expression of EGFR/pEGFR, VEGF, and pVEGFR-2/3 as well as higher microvessel density in KB murine tumors than in YD-10B murine tumors. Conclusion : An orthotopic model of OSCC in athymic mice was established which copies the cervical lymph nodal metastasis of human OSCC. Our mouth floor model should facillitate the understanding of the molecular pathogenesis of cervical nodal metastasis of OSCC.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.6
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• pp.1261-1266
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• 2009

The wrinkle is a typical sign showing aging. These days lots of people want to have a young and healthy appearance and many medical doctors are studying about wrinkle cure. In fact a young face without wrinkle looks more healthy and energetic. Therefore the wrinkle cure is important at the point of medical view. This research is an investigation of several studies about wrinkle cure using acupuncture needle. We have to consider the problem of the whole body which is related 12 meridians and meridian muscles as well as topical skin and tissues. There are three parts affecting wrinkle formation and cure. The first is a meridian and meridian muscle, the second is a local muscle and fascia on the head and neck, the third is a local skin structure. There are three kinds of method to cure the wrinkle locally. The first one is the perpendicular treatment of acupuncture, called the microneedle therapy, the process of this method is that lots of microneedles stab in the skin to dermis. The second one is the transverse treatment of acupuncture. The process of this method is that an acupuncture needle inserts just under the wrinkle skin. The third one is the incision treatment of acupuncture, called subcision, the process of this method is to cut the fibrous band which connect from the facial muscle to SMS(superficial musculoaponeurotic system) using cuttable needle. The hematoma after treatment let a collagen increase.

• Journal of Welding and Joining
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• v.31 no.6
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• pp.50-57
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• 2013

Characterization of microstructures and cryogenic mechanical properties of electro beam (EB) welds between cast and forged Inconel 718 superalloys has been investigated. Optimal EBW condition was found in the beam current range of 36~39 mA with the constant travel speed of 12 mm/s and arc voltage of 120 kV for 10 mm-thick specimens. Electron beam current lower than 25 mA caused to occur the liquation microfissuring in cast-side heat affected zone (HAZ) of EB welds. The HAZ liquation microfissure was found on the liquated grain boundaries with resolidified ${\gamma}/Laves$ and ${\gamma}/NbC$ eutectic constituents. EBW produced welds showing a fine dendritic structure with relatively discrete Laves phase due to fast cooling rate. After post weld aging treatment, blocky Laves phase and formation of ${\gamma}^{\prime}+{\gamma}^{{\prime}{\prime}}$ strengtheners were observed. Presence of primary strengthener and coarse Laves particles in PWHT weld may cause to reduce micro-plastic zone ahead of a crack, leading to a significant decrease in Charpy impact toughness at $-196^{\circ}C$. Fracture initiation and propagation induced by Charpy impact testing were discussed in terms of the dislocation structures ahead of crack arisen from the fractured Laves phase.

• Pediatric Infection and Vaccine
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• v.9 no.1
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• pp.100-103
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• 2002

Streptococcus milleri Goup Bacteria(SMG) comprise three species, Streptococcus anginosus, Streptococcus intermedius, Streptococcus constellatus. Although they are commensal organism, they can be pathogenic. SMG can be aggressive pathogen in the head and neck with a propensity for abscess formation and local extension of the infection. SMG is culturally and biochemically variable, which makes it hard for the clinicians to recognize it. Hence, it seems that this organism has been relatively neglected. Most of the Lancefield F streptococci are SMG. We report one patient who had Group F streptococcal bacteremia and subdural abscess. According to his medical history, he was diagnosed as membranoproliperative glomerulonephritis three years ago. He complained headache although he was treated by appropiate antibiotics. Brain CT was used as a tool to identify the brain abscess. He had surgical drainage and was treated with IV antibiotics postoperatively.