• The Korean Journal of Zoology
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• v.20 no.1
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• pp.29-40
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• 1977

The authors examined fresh-water gammarid materials which were collected from streams in 20 localities of South Korea during the period from 1965 to 1977. As the results of the observation, the authors have concluded as follows: 1. These fresh-water gammarids belong to Gammarus pulex-group and are distributed widely in mountain-streams of mainland and surrounding islands of South Korea. 2. The present specimens are different from the subspecies, G. pulex koreanus Ueno, 1940 which was described originally from North Korea. In the latter, the pulmose setae of third uropod are limited only to the outer margin of both rami. The peduncle and flagellum of second antenna are fringed with a few short setae and the flagellum is provided with calceoli. In the former, both margins of inner ramus and outer margin of outer ramus of third uropod are fringed with long pulmose setae. The peduncle and flagellum of second antenna have abundant relatively long setase and the flagellum is not provided with calceoli. 3. The present specimens are different from the subspecies, G. pulex sobaegensis Ueno, 1966 which was described originally from South Korea. The latter dwells in cave, while the former dwells in mountain-stream. In the former, the arrangements of pulmose setae of third uropod and the setation of second antenna are similar to those of the latter. But they are quite different from each other in several characters such as shape of upper lip, shape of fifth article of second gnathopod and numbers of incisions on front distal margins of coxal plates 1-3. The former has spines on surface of coxal plates 1-3, but the latter has not. In females, the former has four pairs of marsupial plates, while the latter has three pairs. 4. The present materials show local variations. Therefore, they could be divided into 3 local groups. The first group (specimens from Mt. Odae and Mt. Sogeumgang) has pulmose setae on the both margins of both rami of third uropod and second article of outer ramus is relatively long. In general, this group has setae sparsely on the both rami and especially a few setae on the outer margin of outer ramus. The second group, which are widely distributed in South Korea, has pulmose setae on the both margins of inner ramus and on the outer margin of outer ramus of third uropod. In the third group (specimens from Mt. Soyo), the pulmose setation of third uropod is similar to that of the first group, but the second article of outer ramus is very small.

• Journal of Korean Historical Folklife
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• no.46
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• pp.195-237
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• 2014

Palsapum are ornaments to reveal the purpose of commander of three naval forces as well as symbols to remember the greatness of admiral Yi, Sun-Shin. In 1966, ther were designated as a treasure No. 440 based on their value; however, they have not received attention from academia because they are relics from China. This study compares and analyzes the document, paintings, and relevant references from Korea and China focusing on Palsapum, understands their formal characteristics, and examines their historical value such as years and location of creation. As a result, the study determines five of them are original, but three of them were newly created by the later generations. The five, Dodogin (都督印, Commander's seal)·Yeongpae (令牌, Commander's tablet)·Gwido (鬼刀, Replica of the devil sword)·Chamdo (斬刀, Replica of the decapitation swor d)·and Gognapal (bugle) were created by Ming Dynasty before 1598, and delivered by the hands of General Chen Lin. The other three, Dokjeongi (督戰 旗, Battle flag)·Hongsoryeonggi (紅小令旗, Commander's flag)·and Namsoryeonggi (藍小令旗, Commander's flag), were created in 19th century by Joseon Dynasty. After analysis on the former relics, the study determines that they are not official relics with the dignity of Ming Dynasty but personal relics with regional characteristics; in other words, Palsamun are not the royal gifts from Emperor Shenzong to Admiral Yi, Sun-Shin. but personal momentoes left by General Chen Lin in the Tongjeyoung to celebrate the admiral. The names, variety, numbers, and appurtenances of Palsapum have been changed with time as follows. First, the scholars of Jeseon in 17the century only focused on Dodogin. It was certainly created in Ming Dynasty; however, it was a personal stamp, so considered to be not from the emperor but from General Chen Lin. Second, Palsapum was called Palsamul and consisted of 14 pieces of 8 kinds in 18the century, ; it is confirmed on the 「Dosul(圖說, stories with pictures of」 『Yi Chungmugong Literary Collection』 The sizes of five relics including Dodogin are similar to the records, but their patterns and shapes are exotic, or cannot be found in Joseon. Thus, they reflect the regional characteristics of Guangdong province. Third, they were called Palsapum, and consisted on 15 pieces of 8 kinds in 19th century; it is confirmed on , a sixteen-fold folding screen drawn by Shin, Gwan-Ho in 1861. The stamp box, tablet bag, and three flags were newly created to engrave Joseon style letters and patterns on damageable materials such as leather and cloth. The relics easy to be destroyed have been renewed even after 19th century. Last, there are many misunderstandings about Palsapum by governmental indifference and improper management of records even though they were designated as a treasure in very early times. Thus, authorities should be concerned with Palsapum to provide the measures for stable maintenance of the relics; this will let people remember not only the history of cooperation between Korea and China to stop the Japanese ambition, but also Admiral Yi, Sun-Shin and General Chen Lin to bring victory in Japanese invasions of Korea.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.1
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• pp.1-13
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• 2011

The aim of this study was to evaluate shear bond strength of pressed reinforced composite resin ($TESCERA^{TM}$ ATL) veneering to zirconia with various surface treatments. Forty sintered zirconia specimens and forty pockmarked zirconia specimens were fabricated. All the materials were categorized as Group 1 (Control : porcelain veneering on zirconia surface), Group 2 ( $TESCERA^{TM}$ ATL dentine veneering after bonding agent application on zirconia surface), Group 3 ($TESCERA^{TM}$ ATL dentine veneering on pockmarked zirconia surface), Group 4 ($TESCERA^{TM}$ ATL dentine veneering after bonding agent application on pockmarked zirconia surface), Group 5 (Thermocycling on Group 1), Group 6 (Thermocycling on Group 2), Group 7 (Thermocycling on Group 3), and Group 8 (Thermocycling on Group 4). SBS(Shear bond strength) of 8 groups was determined with an Instron Universal Testing Machine. Also fractured surface of specimens were observed with a scanning electron microscope. There were no significant differences in the initial SBS between Group 1(control group), Group 3, and Group 4. (p>0.05) Group 2 presented the lowest SBS values. There was a no significant difference between just as 24hour water storage and simulated aging on pockmarked zirconia groups. (p>0.05) A formation of pockmarked irregularities on zirconia surface as mechanically pitted surface was reliable method for establishing a stronger bond between $TESCERA^{TM}$ ATL and zirconia-based material.

• Korean Chemical Engineering Research
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• v.50 no.4
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• pp.684-689
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• 2012

Poly(acrylic acid) (PAA) microspheres is one of the widely-used polymeric materials for the bio-field application and the electric materials. For the synthesis of PAA microspheres, the polymerization technique using surfactants is applied. After the synthesis, the purification and separation processes are required for the removal of surfactant. When general organic solvents were used, many problems, such as huge amount of waste solvent, additional separation processes, and the possibility of residual media, were occurred. Thus, High-pressure Soxhlet extraction using liquid $CO_2$ was developed to solve these problems. In this study, High-pressure Soxhlet extraction of the synthesized PAA microspheres using liquid $CO_2$ was conducted for the removal of Monasil PCA which is used for the dispersion polymerization of acrylic acid in compressed liquid Dimethyl ether (DME). The morphology of the extracted PAA particles was checked by field emission scanning electron microscopy (FE-SEM) and the residual concentration of Monasil PCA was analyzed by inductively coupled plasma - Optical Emission Spectrometer (ICP-OES). For studying the effect of the solvent effect, Soxhlet extraction was conducted using n-hexane, liquid DME, and liquid $CO_2$. In case of n-hexane, some extracted PAA microspheres were produced. However, deformation was also occurred due to the high thermal energy of n-hexane vapor. Liquid DME could not remove Monasil PCA. When using liquid $CO_2$, the extracted PAA microspheres which were free for the residual solvent were produced without deformation. For finding the optimum operating condition, high-pressure Soxhlet extraction was conducted for 8 hours with changing the temperature of reboiler and condenser. When the extractor temperature is $19.6{\pm}0.2^{\circ}C$ and the pressure is $51.5{\pm}0.5$ bar, the best removal efficiency was obtained.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.1
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• pp.39-46
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• 1999

This study was performed to examine the effect of initial composition ratio and various reaction conditions on CEC and crystallinity of the product in hydrothermal synthesis of zeolitic materials from fly ash. Na-P1 zeolite was formed from the mixture with $SiO_2/Al_2O_3$ ratio above 2.55, however from the mixture with $SiO_2/Al_2O_3$ ratio below 2.25 hydroxy sodalite was formed. The CEC of reaction product(Na-P1 zeolite) treated with 3N-NaOH, $Na_2O/Al_2O_3$ ratio 2.55 and $SiO_2/Al_2O_3$ ratio 2.0 for 12 hours at $103^{\circ}C$ was about $285cmol^+kg^{-1}$, which was higher than those of the products of other reaction condition. The crystallinity of Na-P1 zeolite as high as 45.1% was attained at the optimum reaction condition of 2N-NaOH, $SiO_2/Al_2O_3$ ratio 2.55, $Na_2O/Al_2O_3$ ratio 1.5 for 12 hours at $103^{\circ}C$. The XRD peak of the reaction product could be measured at 7.16, 5.04, 4.12, 3.18, $2.69{\AA}$ and tetragonal pillar shape observed by SEM image be characteristic for Na-P1 zeolite. Judging from the result, it should be considered the optimum synthesis condition for Na-P1 zeolite from fly ash was 2~3N NaOH, $SiO_2/Al_2O_3$ ratio 2.55 and $Na_2O/Al_2O_3$ ratio 1.5~2.0 for 12 hours at $80{\sim}103^{\circ}C$.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.1
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• pp.9-18
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• 2015

Purpose: The purpose of this study is to examine characteristics of implant surface with RBM and anodizing treatments, and to evaluate the responses of osteoblast-like cell (MG-63 cell). Materials and methods: Grade IV titanium disks were fabricated (Diameter 10 mm, thickness 3 mm). Anodizing treatment (ASD) group, RBM and anodizing treatment (RBM/ASD) group, control (machined surface) group were divided. In this study, osteoblast-like cell was used for experiments. The experiments consist of surface characteristics evaluation by FE-SEM images, energy dispersive spectroscopy and stereo-SEM. In order to evaluate cell adhesion evaluation by crystal violet assay and observe cells form by confocal laser microscopy. To assess cell proliferation by XTT assay, cell differentiation by RT-PCR and mineralization by Alizarin red S stain assay. ELISA analyzer was used for Quantitative evaluation. Comparative analysis was run by one-way ANOVA (SPSS version 18.0). Differences were considered statistically significant at P<.05. Results: In ASD group and RBM/ASD group, the surface shape of the crater was observed and components of oxygen and phosphate ions in comparison with the control group were detected. The surface average roughness was obtained $0.08{\pm}0.04{\mu}m$ in the control group, $0.52{\pm}0.14{\mu}m$ in ASD group and $1.45{\pm}0.25{\mu}m$ in RBM/ASD group. In cell response experiments, ASD group and RBM/ASD group were significantly higher values than control group in cell adhesion and mineralization phase, control group was the highest values in the proliferative phase. In RT-PCR experiments, RBM/ASD group was showed higher ALP activity than other groups. RBM/ASD group in comparison with ASD group was significantly higher value for cell adhesion and proliferation phase. Conclusion: In the limitation of this study, we are concluded that the surface treatment with RBM/ASD seems more effective than ASD alone or machined surface on cellular response.

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.1
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• pp.53-60
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• 2012

Purpose: The purpose of this study was to compare Ni-Cr alloy property of gas-oxygen torch soldering and infrared welding using optical microscope and Electron Probe Micro Analyzer (EPMA). Materials and methods: Ni-Cr alloys were casted for specimens. Specimens had 3.0 mm diameter, 30.0 mm length and were divided into two groups. Each group had 4 specimens. One group was for gas-oxygen torch soldering and the other was infrared welding. Specimens were cut with low-speed disc and soldered each other with gas-oxygen torch and infrared machine. After soldering and polishing, specimens were observed at 3 points (soldering point, 5 mm distance point, 10 mm distance point) with optical microscope and analyzed 3 points (soldering point, 5 mm distance point, 10 mm distance point with EPMA. Results: The results of this study were as follows: 1. The observation of gas-oxygen torch soldering at 10 mm distance point under the optical microscope was not founded any specific surface properties, but some crack lines were observed at 5 mm distance and soldering point. 2. There were no crack lines were founded at the observation of infrared welding at 10 mm distance and 5 mm distance points under the optical microscope. However, at the 5 mm distance, the surface was not smooth enough compared with at 10 mm distance point. Some crack lines were observed at the welding point as well. 3. In the EPMA analysis of the gas-oxygen torch soldering, the component of Ni was increased by 4.5%, Cr was increased by 7.5% than that of the Ni-Cr alloy at the 10.0 mm distance. At the 5 mm distance, the component of Ni was decreased by 6.1%, Mo was increased by 9.0% than that of the Ni-Cr alloy but Cr was equally shown at the 5.0 mm distance. Only Ni was shown at the soldering point. 4. In the EPMA analysis of the infrared welding, the component of Ni was increased by 9.1%, Cr was increased by 0.4% than that of the Ni-Cr alloy but Al was equal at the 10.0 mm distance. At the 5 mm distance, the component of Ni was increased by 4.7%, Cr was increased by 4.7% and Al was increased by 0.1% than that of the Ni-Cr alloy. At the welding point, the component of Ni was increased by 8.8%, Cr was increased by 8.2% than that of the Ni-Cr alloy. Conclusion: From these results, at the 5 mm distance from the soldering point, the surface of the infrared welding was more smoother than that of the gas-oxygen torch soldering. On the EPMA analysis, the component of the specimens with infrared welding was more similar than that of the gas-oxygen torch soldering compared with the component of the Ni-Cr alloy.

• Parasites, Hosts and Diseases
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• v.21 no.2
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• pp.241-245
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• 1983

PraziquantEI ($Distocide^{\circledR}$), the KcrEan product, was tEstEd for its safety and Efficacy in treatmEnt of Clonorchis sinensiJ infccticn during the period from April to SeptembEr, 1983 in Korea. A total of 55 egg positive cases were selected and treated with the regimen of 25 mg/kg t.i.d. for 1 day (total 75 mg/kg). The follow-up stool examination was done in 47 cases by cellophane thir;k smear and Stoll's egg counting techniques. The 8 uncured cases were treated again with the same regimen. The laboratory tests for blood picture and liver function were done in 27 cases and compared before and after the treatment. The results obtainEd are as follows: 1. After single course treatment, the cure and egg reduction rates were 83.0 and 99.1% respectively. With the second treatment, excellent results of 100% in both rates were obtained. 2. Several kinds of side effects such as dizziness, headache, etc. were complained by 29 cases (61.7 %), however, those were so mild and transient that no special treatment was necessary. 3. No significant change in laboratory findings was recognizable before and after the treatment. From the above results, it is concluded that $Distocide^{\circledR}$ is as effective and safe as $Biltricide^{\circledR}$ and highly recommendable in treatment of C. sinensis infection.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.3
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• pp.245-253
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• 2011

Purpose: The aim of this in vitro study was to estimate surface characteristic after peptide coating and investigate biological response of human mesenchymal stem cell to anodized titanium discs coated with RGD peptide by physical adhesion and chemical fixation. Materials and methods: Fluorescence isothiocyanate (FITC) modified RGD-peptide was coated on the anodized titanium discs (diameter 12 mm, height 3 mm) using two methods. One was physical adhesion method and the other was chemical fixation method. Physical adhesion was performed by dip and dry procedure, chemical fixation was performed by covalent bond via silanization. In this study, human mesenchymal stem cell was used for experiments. The experiments consisted of surface characteristic evaluation after peptide coating, analysis about cell adhesion, proliferation, differentiation, and mineralization. Obtained data are statistically treated using Kruskal-Wallis test and Bonferroni test was performed as post hoc test (P=.05). Results: The evaluation of FE-SEM images revealed no diffenrence at micro-surfaces between each groups. Total coating dose was higher at physical adhesion experimental group than at chemical fixation experimental group. In cell adhesion and proliferation, RGD peptide coating did not show a statistical significance compared with control group (P>.05). In cell differentiation and mineralization, physical adhesion method displayed significantly increased levels compared with control group and chemical fixation method (P<.05). Conclusion: RGD peptide coating seems to enhance osseointegration by effects on the response of human mesenchymal stem cell. Especially physical adhesion method showed more effective than chemical fixation method on response of human mesenchymal stem cell.

• Journal of Chest Surgery
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• v.31 no.8
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• pp.739-748
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• 1998

Background: It has been well documented that transient occlusion of the coronary artery causes myocardial ischemia and finally cell death when ischemia is sustained for more than 20 minutes. Extensive studies have revealed that ischemic myocardium cannot recover without reperfusion by adequate restoration of blood flow, however, reperfusion can cause long-lasting cardiac dysfunction and aggravation of structural damage. The author therefore attempted to examine the effect of postischemic reperfusion on myocardial ultrastructure and to determine the rationales for recanalization therapy to salvage ischemic myocardium. Materials and methods: Young Holstein-Friesian cows(130∼140 Kg body weight; n=40) of both sexes, maintained with nutritionally balanced diet and under constant conditions, were used. The left anterior descending coronary artery(LAD) was occluded by ligation with 4-0 silk snare for 20 minutes and recanalized by release of the ligation under continuous intravenous drip anesthesia with sodium pentobarbital(0.15 mg/Kg/min). Drill biopsies of the risk area (antero-lateral wall) were performed at just on reperfusion(5 minutes), 1-, 2-, 3-, 6-, 12-hours after recanalization, and at 1-hour assist(only with mechanical respiration and fluid replacement) after 12-hour recanalization. The materials were subdivided into subepicardial and subendocardial tissues. Tissue samples were examined with a transmission electron microscope (Philips EM 300) at the accelerating voltage of 60 KeV. Results: After a 20-minute ligation of the LAD, myocytes showed slight to moderate degree of ultrastructural changes including subsarcolemmal bleb formation, loss of nuclear matrix, clumping of chromatin and margination, mitochondrial destruction, and contracture of sarcomeres. However, microvascular structures were relatively well preserved. After 1-hour reperfusion, nuclear and mitochondrial matrices reappeared and intravascular plugging by polymorphonuclear leukocytes or platelets was observed. However, nucleoli and intramitochondrial granules reappeared within 3 hours of reperfusion and a large number of myocytes were recovered progressively within 6 hours of reperfusion. Recovery was apparent in the subepicardial myocytes and there were no distinct changes in the ultrastructure except narrowed lumen of the microvessels in the later period of reperfusion. Conclusions: It is likely that the ischemic myocardium could not be salvaged without adequate restoration of coronary flow and that the microvasculature is more resistant to reversible period of ischemia than subendocardium and subepicardium. Therefore, thrombolysis and/or angioplasty may be a rational method of therapy for coronarogenic myocardial ischemia. However, it may take a relatively longer period of time to recover from ischemic insult and reperfusion injury should be considered.