• Journal of Chest Surgery
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• v.12 no.4
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• pp.383-394
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• 1979

Treatment of valvular heart disease with valve replacement has been one of the most popular procedures in cardiac surgery recently. Although, first effort was directed toward the prosthetic valve, it soon became popular that bioprosthesis, the valvular xenograft, was prefered in the majority cases. Valvular xenograft has some superiority to the artificial prosthetic valve in some points of thromboembolism and hemolytic anemia, and it also has some inferiority of durability, immunologic reaction and resistance to Infection. Tremendous efforts were made to cover the inferiority with several methods of collection, preservation, and valve mounting of the porcine valve or pericardium of the calf, and also with surgical technique of the valvular xenograft replacement. Auther has collected 320 porcine aortic valves immediately after slaughter, and aortic cusps were coapted with cotton balls in the Valsalva sinuses to protect valve deformity after immersion in the Hanks' solution, and oxidation, cross-linking and reduction procedures were completed after the proposal of Carpentier in 1972. Well preserved aortic valves were suture mounted in the hand-made tissue valve frame of 19, 21, and 23 mm J.d., and also in the prosthetic vascular segment of 19 mm Ld. with 4-0 nylon sutures after careful trimming of the aortic valves. Completed valves were evaluated with bacteriologic culture, pressure tolerance test with tolerane gauge, valve durability test in the saline glycerine mixed solution with tolerance test machine in the speed of 300 rpm, and again with pathologic changes to obtain following results: 1. Bacteriologic culture of the valve tissue in five different preservation method for two weeks revealed excellent and satisfactory result in view of sterilization including 0.65% glutaraldehyde preservation group for one week bacteriologic culture except one tissue with Citobacter freundii in 75% ethanol preserved group. 2. Pressure tolerance test was done with an apparatus composed of V-connected manometer and pressure applicator. Tolerable limit of pressure was recorded when central leaking jet of saline was observed. Average pressure tolerated in each group was 168 mmHg in glutaraldehyde, 128 mmHg in formaldehyde, 92 mmHg in Dakin's solution, 48 mmHg in ethylene oxide gas, and 26 mmHg in ethanol preserved group in relation to the control group of Ringer's 90 mmHg respectively. 3. Prolonged durability test was performed in the group of frame mounted xenograft tissue valve with 300 up-and-down motion tolerance test machine/min. There were no specific valve deformity or wearing in both 19, 21, and 23 mm valves at the end of 3 months (actually 15 months), and another 3 months durability test revealed minimal valve leakage during pressure tolerance test due to contraction deformity of the non-coronary cusp at the end of 6 months (actually 30 months) in the largest 23 mm group. 4. Histopathologic observation was focussed in three view points, endothelial cell lining, collagen and elastic fiber destructions in each preservation methods and long durable valvular tolerance test group. Endothel ial cell lining and collagen fiber were well preserved in the glutaraldehyde and formaldehyde treated group with minimal destruction of elastic fiber. In long durable tolerance test group revealed complete destruction of the endothelial cell lining with minimal destruction of the collagen and elastic fiber in 3 month and 6 month group in relation to the time and severity. In conclusion, porcine xenograft treated after the proposal of Carpentier in 1972 and preserved in the glutaraldehyde solution was the best method of collection, preservation and valve mounting. Pressure tolerance and valve motion tolerance test, also, revealed most satisfactory results in the glutaraldehyde preserved group.

• Archives of Craniofacial Surgery
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• v.11 no.2
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• pp.103-106
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• 2010

Purpose: Giant cell tumors of the bone are rare, locally aggressive lesions that primarily affect the epiphysis of the long bones in young adults. These tumors occur very rarely on the skull, principally in the sphenoid and temporal bones. The occipital bone is an unusual site. We report a rare case of a giant cell tumor of the occipital bone with a review of the relevant literature. Methods: A 7-year-old boy presented with a mass of the right occipital area, which was accompanied by localized tenderness and mild swelling. The mass was first recognized approximately 1 year earlier and grew slowly. There was no significant history of trauma. The physical examination revealed a nonmobile and non-tender bony swelling on the occipital region. The neurological evaluation was normal. The serial skull radiography and CT scan showed focal osteolytic bone destruction with a bulged soft tissue mass in the right occipital bone. The patient underwent a suboccipital craniectomy and a complete resection of the epidural mass. The lesion was firm and cystic. The mass adhered firmly to the dura mater. Results: The postoperative clinical course was uneventful, and the patient was discharged 5 days later. The histopathology report revealed scattered multinucleated giant cells and mononuclear stromal cells at the tumor section, and the giant cells were distributed evenly in the specimen, indicating a giant cell tumor. Conclusion: Giant cell tumors are generally benign, locally aggressive lesions. In our case, the lesion was resected completely but a persistent long term follow up will be needed because of the high recurrence rate and the possible transformation to a malignancy.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.1
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• pp.157-168
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• 2006

Recently, interest in using Al alloys in ship construction instead of fiber-reinforced plastic (FRP) has increased because of the advantages of A) alloy ships over FRP ships, including high speed, increased load capacity. and ease of recycling. This paper investigated the mechanical and electrochemical properties of Al alloys in a slow strain rate test under various potential conditions. These results will provide reference data for ship design by determining the optimum protection potential regarding hydrogen embrittlement and stress corrosion cracking. In general, Al and Al alloys do not corrode on formation of a film that has resistance to corrosion in neutral solutions. In seawater, however, $Cl^-$ ions lead to the formation and destruction of a Passive film. In a potentiostatic experiment. the current density after 1200 sec in the Potential range of $-0.68\~-1.5\;V$ was low. This low current density indicates the protection potential range. Elongation at an applied potential of 0 V was high in this SSRT. However, corrosion protection under these conditions is impossible because the mechanical properties are worse owing to decreased strength resulting from the active dissolution reaction in parallel parts of the specimen. A film composed of $CaCO_3\;and\;Mg(OH)_2$ confers corrosion resistance. However, at potentials below -1.6 V forms non-uniform electrodeposition coating, since there is too little time to form a coating. Therefore, we concluded that the mechanical properties are poor because the effect of hydrogen gas generation exceeds that of electrodeposition. Comparison of the maximum tensile strength, elongation, and time to fracture indicated that the optimum protection potential range was from -1.45 to -0.9 V (SSCE).

• Korean Journal of Environmental Biology
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• v.28 no.2
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• pp.101-107
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• 2010

Metal ions are essential to life. However, some metals such as mercury are harmful, even when present at trace amounts. Toxicity of mercury arises mainly from its oxidizing properties. Ionizing radiation (IR) is an active tool for destruction of cancer cells and diagnosis of diseases, etc. IR induces DNA double strand breaks in the nucleus, In addition, it causes lipid peroxidation, ceramide generation, and protein oxidation in the membrane, cytoplasm and nucleus. Yeasts have been a commonly used material in biological research. In yeasts, the physiological response to changing environmental conditions is controlled by the cell types. Growth rate, mutation and environmental conditions affect cell size and shape distributions. In this work, the effect of IR and mercury chloride (II) on the morphology of yeast cells were investigated. Saccharomyces cerevisiae cells were treated with IR, mercury chloride (II) and IR combined with mercury chloride (II). Non-treated cells were used as a control group. Morphological changes were observed by a scanning electron microscope (SEM). The half-lethal condition from the previous experimental results was used to the IR combined with mercury. Yeast cells were exposed to 400 and 800 Gy at dose rates of 400Gy $hr^{-1}$ or 800 Gy $hr^{-1}$, respectively. Yeast cells were treated with 0.05 to 0.15 mM mercury chloride (II). Oxidative stress can damage cellular membranes through a lipidic peroxidation. This effect was detected in this work, after treatment of IR and mercury chloride (II). The cell morphology was modified more at high doses of IR and high concentrations of mercury chloride(II). IR and mercury chloride (II) were of the oxidative stress. Cell morphology was modified differently according to the way of oxidative stress treatment. Moreover, morphological changes in the cell membrane were more observable in the frequently stress treated cells than the temporarily stress treated cells.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.2
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• pp.188-193
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• 2014

Seed viability testing provides valuable information for assessing seed lot germinability. However, most testing methods require destruction of seed prior to test. Because the dissected seeds for viability test cannot be used further evaluation, the nondestructively X-ray photography technique that can be applied for the evaluation of seed quality has been developed. In order to know the validity and accuracy of X-ray photography technique in seed evaluation test that conducted to remove the abnormal seed from a seed lot, we have compared the results from tetrazolium viability test, germination test and X-ray contrast method in cotton. Metallic salts treatment increased the efficiency of X-ray photographic method by enhancing the penetration of X-ray in abnormal or damaged seeds rather than normal seeds that have strong and well-organized tissues in seed. Cotton seeds presoaked for 16 hr in distilled water followed by soaking into metallic salt solution (5% NaI in water) for 60 min were easily classified seeds into dead seed and viable seed based on the radiography images obtained by X-ray radiation. We concluded that soft X-ray photography was reliable to find out the various defective characters due to heat and mechanical damage of seeds.

• Journal of Technology Innovation
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• v.15 no.2
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• pp.123-152
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• 2007

The striking characteristic of the contemporary global security environment is that the nature of threats has become diverse and complex. For example, transnational and non-military threats including terrorism and proliferation of weapon of mass destruction has increased. In this security environment, Advanced countries funnel their investments for defense budgets into the assurance of key force capability and R&D of cutting-edge core technologies, in consideration of future battlefield environments so as to get an edge on not only defense science and technology but also intelligence capabilities. As shown by past practices of the korea's defense acquisition, the ministry of national defense has tried to enhance its force capabilities in the short-term by purchasing foreign weapon systems rather than by investing in domestic R&D. Accordingly, the technological gaps between the korea and advanced countries were widened due to both insufficient investment in development of domestic technologies and avoidance of technological transfer by advanced countries. Thus, for the effective execution of the R&D budget and the successful performance of the projects, the importance of selection, management and evaluation of the R&D projects is emphasized. So, The objective of this study is that the analysis of the proposal-selection evaluation system for the realization of the successful defense core technology R&D projects. This study focused on the improvement of the proposal-selection evaluation model which can be applicable to the national defense core R&D projects. Using the improved proposal-selection evaluation system, we propose a model to enhance the reliability of the national defense core technology R&D project evaluation system.

• Journal of Wetlands Research
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• v.13 no.3
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• pp.481-488
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• 2011

Various development activities have lead to the destruction of the ecosystem such as natural wetlands. In order to protect these natural wetlands, the Ministry of Environment (MOE) in Korea enacted the Wetland Conservation Act in 1999 and designated protected areas for wetland conservation. The MOE adapted the use of Best Management Practices (BMP) such as retention ponds and constructed wetlands to treat the polluted water before entering the water system. One of these projects was a free-water surface flow (FWS) constructed wetland built as a secondary treatment unit for piggery wastewater effluent coming from a livestock wastewater treatment facility. Water quality monitoring for the constructed wetland was conducted during rainfall events. The results showed that the average removal efficiencies of TSS, BOD, TN, TP were 86, 60, 45, 70%, respectively. It was observed that the removal efficiency of particulate matter and phosphorus was high compared to nitrogen. Therefore, a longer hydraulic retention time was needed in order to improve the treatment efficiency of nitrogen. The results of this study can contribute to the wetland design, operation and maintenance of constructed wetlands.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.1
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• pp.26-31
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• 2011

Purpose: Chronic inflammatory gingival lesions occur as pyogenic granulomas or non-specific chronic suppurative lesions. Methods: Of the 59 chronic inflammatory gingival lesions examined, plasma cell granuloma (n=14), which showed an intense antibody-mediated immune reaction with the increased infiltration of plasma cells, was observed as a pseudotumor-like gingival overgrowth and myofibroblastic or fibrohistiocytitc proliferation of stromal cells with a heavy collection of plasma cells. The levels of CD3, CD20, CD31, CD68, RANKL, cathepsin G, cathepsin K, lysozyme, TNF${\alpha}$, MMP-2, and MMP-9 in the 14 cases of gingival plasma cell granuloma with immunohistochemical detection were measured to determine the pathogenetic progresses of the plasma cell granuloma compared to the common pyogenic granuloma (n=45) in the gingiva. Results: The gingival lesions of the plasma cell granuloma could be divided into three histological types, plasma cell predominant type (PPT, n=8), mixed inflammatory cell type (MICT, n=2), and sclerosed fibrosis type (SFT, n=4). The PPT showed a condensed infiltration of plasma cells into the perivascular spaces of the granulomatous lesion with frequent formation of Russel's body in their cytoplasm. The MICT showed the concomitant infiltration of many macrophages together with plasma cells, resulting in the diffuse destruction of stromal fibrous tissue. The SFT showed granulomatous lesions replaced gradually by thick collagenous fibrous tissue, resembling an inflammatory pseudotumor. The SFT expressed strongly the lymphocytic markers, CD3 and CD20, and the macrophage/monocyte markers, CD31 and CD68, but showed reduced expression of common inflammatory markers, TNF${\alpha}$, cathepsin G, lysozyme, MMP-2, and MMP-9, as well as the reduced expression of osteoclastogenic markers, RANKL and cathepsin K. Conclusion: These results suggest that a gingival plasma cell granuloma shows variable gene expression for cell-mediated immunity and stromal tissue degeneration, undergoing sclerotic fibrosis with a persistent inflammatory reaction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.8
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• pp.3430-3438
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• 2011

The purpose of this study is to set the Korean mandarine quality standards based on consumer preference survey. Until now the Korean mandarine's quality standards has been based on the fruit size. The Korean mandarine's quality in agricultural cooperative, citrus agricultural cooperative federation, and some agricultural corporation has been selected in accordance with its own brand of quality grade using a non-destruction sorting machine. But, setting the Korean mandarine's quality standards has been based on the convenient and routine method rather than the scientific and objective method, consumer's preference. According to the grade contents, the highest grade brand was required more than sugar $12^{\circ}Bx$ and less than acid 1.0% and the following grade brand was required more than sugar $11^{\circ}Bx$ and less than acid 1.0% uniformally. Thus, in this study, based on the consumers' preference of Korean mandarine, 4-level grades of sugar and 4-level grades of acidity were divided into the total 16-level grades. Based on them, 5-level grades were set.

• Toxicological Research
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• v.22 no.2
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• pp.87-93
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• 2006

The KFDA (Korea Food & Drug Administration) has performed a collaborative toxico-genomics project since 2003. Its aim is to construct a toxicologenomic database of 12 hepatotoxic compounds from mice livers. Phenylbutazone which is non-steroidal anti-inflammatory drug was assigned. It was administered at low (0.0238 mg/kg) and at high (0.238 mg/kg) dose (5 mice per group) orally to the postnatal 6 weeks ICR mice, then the serum and liver were collected at the indicated time (6, 24 and 72 h) after administration. Serum biochemical markers for liver toxicity were measured and histopathologic studies also were carried out. The gene expression profiling was carried out by using Applied Biosystems 1700 Full Genome Expression Mouse. The 2-way ANOVA was used to find genes that reflected phenylbutazone-induced acute toxicity or dose-dependant changes. By self-organization maps (SOM), we identified groups with unique gene expression patterns, some of them are supposed to be related to phenylbutazone induced toxicity, including lipid metabolism abnormality, oxidative stress, cell death and cytoskeleton destruction.