• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제32권2호
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• pp.117-128
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• 2006

Free flap transplantation with microvascular anastomosis has been successfully performed by development of surgical technique, materials and postoperative monitoring equipments of flap. But success rate of microvascular anastomosis is influenced by various factors, and failure rate is about 5-10%. The most influential factor for success rate is surgical technique and other factors that influence failure of microvascular anastomosis are ischemic time of free flap, thrombus formation of anastomosis region and vascular spasm. Many studies has been published in microvascular anastomosis with histologic effect for irrigating solution. But local irrigation solution has been used clinically in microvascular anastomosis, the comparison with each solution, microhistological study for endothelial cell repair and vascular patency has not been reported. The heparin which is anti-thrombotic agent, and urokinase which is fibrinolytic agent are used for this study. Vascular patency and thrombus formation in experimental micro-arterial anastomosis, and endothelial repair were observed with histologic analysis, scanning electron microscopy, transmission electron microscopic examination. The results were obtained as follows: 1. In vascular patency test in 30 minute and 7 days after micro-arterial anastomosis, equal effects of good vascular patency were obtained in group of local irrigation with heparin and urokinase. 2. In thrombus formation in 7 days after micro-arterial anastomosis, equal effects of minimal thrombus formation were obtained in group of local irrigation with heparin and urokinase. 3. In toluidin blue staining in 7 days after micro-arterial anastomosis, local destruction of endothelial cell and inner elastic lamina were seen and endothelial repair was not seen. 4. In scanning electron microscope examination in 7 days after micro-arterial anastomosis, endothelial cell was not seen in peripheral to suture materials, thrombus associated fibrin network was observed. 5. In transmission electron microscope examination in 7 days after micro-arterial anastomosis, inflammatory cell was seen within smooth muscle cells in site of endothelial cell destruction, smooth muscle cell around suture material were arranged irregularly, some collagenous change were seen. From the results obtained in this study, same results of good vascular patency and anti-thrombotic effect of heparin and urokinase were obtained as a local irrigation solution, and repair of endothelial cell was not seen in 7 days after micro-arterial anastomosis.

• Parasites, Hosts and Diseases
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• 제34권1호
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• pp.15-20
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• 1996

이 실아메바(Entamoeba histoIytica)와 동형 아메바(Entamoebc dispar. 동형아메바)의 포낭은 형태학적으로 구분이 안되어 종 감별에 관하여 논란이 있어 왔다. 최근에 이 둘이 별종이며 특히 이질아메바는 병원성이고 동형아메바는 비병윈성입이 확인퇴어 그 감별이 중요한 의미를 갖게 피었나 이 연구에서는 우리 나라의 아메바 분리체를 중합효소 반응과 제한효소 반응을 이용하여 두 종으로 감별하였다. 1994-1995년에 대변을 통강의 방법으로 검색하여 포낭이나 영양형이 발견된 검체를 로빈슨 배지에서 배양하고 배양된 영양형에서 DNA를 분리하였다. PI 유전자 염기서열 중에서 시발페(primer)를 만득어 중합효소 반응으로 482 bp 크기의 산물을 얹고 이를 제한효소(Tuq I, Xmn I, Acc I)로 처리하였다. 또한 Xmn I과 Acc I 제한 효소의 특이 염기서열온 고함하는 시발체를 제작하여 따로 중합효소 반응을 시행하였다. 그 결과 13개 분리체 중에서 S9, S12, YS-6, YS-27의 482 bp 산물은 Taq I과 Xmn I 의하여 그 외의 분리체 산물은 Acc I에 의하여 절단되었다. 이 결과는 특이 염기서열 시발체의 중합효소 반응에서 얻은 산물과 일치하였다, 이 결과에 의하여 분리체 S9, S12, YS-6는 대장염 창자에서. YS-27은 간농양 환자에서 분리한 병원성의 이질아메바(E. histolytica)이고 분리체 S1, S3, S11, S15, S16, S17, S20, YS-17, YS-44는 부증상의 포낭배출자에서 얻은 비병원성의 동형아메바(E. nispur)로 구별할 수 있었다. S1은 설사 환자에서 얻은 분리체 이지탄 동형아메바임을 확인하였고 따라서 이 환자의 설사는 다른 원인에 의한 것으로 판단 된다. 이로써 비병원성인 동형아메바가 우리 나라에서도 병원성 이질아메바보다 더 흔하게 존재한다는 것을 처음으로 기록하며 E. dispar의 우리 말 이름을 동형아메바로 제안한다.

• 대한화학회지
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• 제41권11호
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• pp.594-599
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• 1997

RF 스피터링법을 써서 $Li_{2x}Ni_{1-x}O$ 박막을 제조하였으며, 그 과정에서 기판의 온도$(50/230^{\circ}C)와$ 분위기 $(Ar/O_2)$를 변수로써 막의 미세구조를 조절하였다. 투과전자현미경을 이용한 막 구조 분석에 의해 낮은 기판 온도와 $O_2$ 조건에서 막의 조성입자가 작아짐을 관찰하였고, $50^{\circ}C/O_2$ 하에서 얻이진 $Li_{2x}Ni_{1-x}O$ 박막은 약 $80\AA$ 크기의 입자로 이루어져 있었다. 전기화학적 조건 하에서 $Li_{2x}Ni_{1-x}O$ 박막의 변색현상을 조사한 결과, 박막의 미세구조 발달에 의해 $Li^+$ 이온의 가역적 수용량이 증가하고, 결과적으로 전기변색 기능이 향상됨을 알 수 있엇다. 50 $^{\circ}C/O_2$ 하에서 얻어진 170 nm 두께의 $Li_{2x}Ni_{1-x}O$ 박막은 30 mC/$cm^2$의 $Li^+$ 이온 수용력과 함께 약 1.3의 흡광밀도(OD)를 나타내었다.

• Restorative Dentistry and Endodontics
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• 제17권2호
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• pp.307-330
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• 1992

The aim of this study was to investigate the physical properties of visible light curing Glass Ionomer cement for restorative esthetic filling. The control group was the autopolymerizing GC Fuji II Glass Ionomer cement (2.2: 1 P/L ratio) and the experimental groups were made by following procedure. To induce the polymerization by visible light, the powder of GC Fuji II GI cement and the liquid of Vitrabond for base & liner were mixed in an amalgam capsule with 2.5:1, 3.0:1, 3.5:1 P/L ratio (% wt/wt). After fabrication of specimens, compressive strength, fracture toughness ($K_{IC}$) Scanning Electron Microscope and X-ray Diffraction, water-leachable content, marginal leakage and surface roughness were studied. The results were as follows: 1. Only experimental No. 1 group (visible light curing) showed less compressive strength than control group 1 hour after curing. Strength was increased with aging in all groups, so the compressive strength of light curing groups was no less than that of autopolymerizing group after 3 weeks. 2. Experimental No.3 group (visible light curing) was inferior to No.2 group (visible light curing) in fracture resistance but light curing groups were more resistant to fracture than autopolymerizing group and showed ductile fracture pattern as compared with the brittle fracture pattern of autopolymerizing group. 3. From scanning electron microscopic image, various sized unreacted powder particles, surrounded by silica gel, were embedded in polysalt matrix. Light curing groups showed little crack and more dense unreacted particles than autopolymerizing group. 4. From X-ray diffraction analysis, GC Fuji II Glass Ionomer cement powder and all groups showed glassy appearance but light curing groups seemed to be more intensive in crystaline than autopolymerizing group. S. The most significant dissolution was shown in early setting period in all group. Light curing groups were dissolved less than autopolymerizing group. 6. Marginal leakage was not different significantly in case of cavity margin composed of same tooth structure (ex. only enamel margin, only dentin margin) but much more leakage was shown in dentin/cementum margin than enamel margin. In only case of only enamel margin, light curing groups were superior to autopolymerizing group. 7. All groups showed relatively smooth surface, which irregularity was less than $1{\mu}m$. Light curing groups were smoother than autopolymerizing group.

• Journal of the Korean Wood Science and Technology
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• 제37권4호
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• pp.330-339
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• 2009

본 연구에서는 삼나무 재색제어에 적합한 적정 열처리 조건을 구명하고, 열처리에 따른 다양한 재질변화를 평가하고자 하였다. 국산 삼나무에 대한 온도제어 열처리를 통하여, $170^{\circ}C$ 이상의 열처리 조건에서 심변재 사이의 재색차이가 줄어드는 경향을 확인하였으며, 이러한 경향은 처리시간이 증가함에 따라 더 크게 나타났다. 열처리재의 평형함수율이 무처리재에 비해 50% 정도 낮아 목재의 사용과정에서 나타나는 수분에 의한 성능저하 문제를 예방할 수 있을 것으로 기대되며, 열처리가 부후균에 대한 내후성 증가에도 영향하는 것으로 확인됨에 따라 친환경 방부처리 기술로써 열처리의 적용에 대한 본격적인 연구가 필요할 것으로 판단된다. 열처리재의 역학성능은 무처리재에 비해 대체로 증가하는 것으로 나타났으나, 연성이 감소함으로 인하여 충격휨흡수에너지는 크게 감소하는 결과를 보여 열처리재의 용도를 결정하는데 있어서 이러한 물성 변화가 고려되어야 할 것이다. 열처리에 의한 물성변화의 원인을 규명하기 위하여 미세구조의 변화를 관찰하였으나 특별한 차이는 나타나지 않았다. 따라서 화학성분의 변화를 분석함으로써 물성변화의 원인을 규명하는 추가적인 연구가 필요할 것으로 여겨진다.

• 한국약용작물학회지
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• 제21권6호
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• pp.474-485
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• 2013

Pharmacological studies and clinical practices have indicated that Radix Astragali, a dried root of Astragalus membranaceus possesses a lot of biological activities, including antioxidant, hepatoprotective, anti-diabetic, tonic, diuretic, antimicrobial, antiviral, and immunological activities. These biological activities approved by the modern pharmacological studies are mainly due to the constituents of Astragalus membranaceus including polysaccharides, saponins, flavonoids, amino acids, and trace elements. In resent, the main constituents in the root part showing a lot of biological activities has been isolated also from the aboveground parts such as leaves and sprouts in our laboratory. However, the safety evaluation for the aboveground parts of Astragalus membranaceus should be checked before expanding their application as one of food. In the study, a 90-day rat oral gavage study has been conducted with the extracts from Astragalus membranaceus-above-ground parts at doses of 1000, 3000, and 5000mg/kg/day. The following endpoints were evaluated: clinical observations, body weight, gross and microscopic pathology, clinical chemistry, and hematology. Based on the analysis of these endpoints, it was estimated that NOEL (no observed effect level) for male rats and NOAEL (no observed adverse effect level) for female rats are 5000mg/kg/day of the water-extracts from Astragalus membranaceus-aboveground parts.

• 미생물학회지
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• 제36권2호
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• pp.142-149
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• 2000

국내에서 유행하는 Plasmodium vivax의 유전자를 조작하여 만든 재조항 Circumsporozrozite(CS) 단백질 (22)을 이용하여 말라리아에 대한 혈청학적 검사의 유용성을 평가하였다. 최초발병일로부터 진단까지 걸린 기간을 기준으로 환자들의 면역반응을 Western blot으로 알아본 결과, 15일 이내에 진단받은 환자들은 43.8%(14/32)가 양성반응을 보였고, 16일 이상 경과한 환자들은 94.4%(17/18)가 양성반응을 보여 전체적으로는 62%(31/50)의 양성률을 보였다. Blood stage 항원에 대한 항체를 갖고 있음에도 불구하고 재조합 CS단백질 항원에 대해 음성인 환자들이 22.6%(7/31)였다. 비유행지 주민(경북 예천군)들은 10.7%(3/28),유행시 주민(인천시 강화군)들은 27.6%(13/47)의 재조합 CS 단백질에 대한 항체 양성을 보였다. 재조합 CS 단백질 항원의 역학조사시 유용성을 알아보기 위하여 말라리아 유행지인 경기도 파주시 조산리, 마정리, 항양리, 뇌조리 거주 주민 422명의 전혈을 채취하여 혈액도말법과 중합효소연쇄 반응법으로 항원검사를 실시하였으며 blood stage 항원을 이용한 간접면역형광법과 재조합 CS 단백질 항원을 이용한 효소면역측정법으로 말라리아 항체보유 여부를 조사하였다. 혈액도말법에서는 422명 모두 음성이었으나, 중합효소연쇄반응법에서는 2명(0.47%)이 양성이었다. 간접면역형광법에서는 42명(9.95%), 재조합 CS 단백질 항원을 이용한 효소변역측정법에서는 71명(16.82%)이 양성으로 나타났다. 두 검사에서 모두 항체 양성을 보인 사람은 8명(11.27%)에 불과하였다.

• Composites Research
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• 제27권5호
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• pp.183-189
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• 2014

광학 현미경 관찰을 통해 산화 그래핀의 형상, 크기 및 두께를 쉽게 파악할 수 있는 광학 관찰을 위한 최적 조건을 확보하고자 하였다. 본 연구에서는 $SiO_2$ 절연막이 300 nm 두께로 도포된 실리콘 기판 위의 산화 그래핀을 하이드라진 증기 환원을 통하여 본래의 모폴로지를 유지한 채 환원된 산화 그래핀의 이미지의 선명도를 증가시켰고, 녹색 필터를 사용한 관찰을 통해 이미지의 대비값을 보다 증대시켰다. 추가적으로 얻어진 광학 이미지를 RGB 채널별로 분리하는 방법을 제안하고 이를 통해 이미지를 분석하였다. 그 결과 하이드라진 증기 환원 처리 및 녹색 파장에서의 광원 하에서 고대비의 이미지 확보가 가능하였으며, 더불어 광학 이미지의 RGB 채널 분리만으로도 선명한 그래핀 이미지를 얻을 수 있음을 알아내었다.

• Journal of Periodontal and Implant Science
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• 제28권2호
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• pp.351-372
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• 1998

The purpose of this study was to evaluate in vitro effects of the loss of tooth substance and root surface changes following root planing with various periodontal instruments. The 39 extracted human teeth due to severe periodontal disease were included. The total 50 root surfaces of 30 teeth were root planed with following instruments : Group 1, with Gracey curette, Group 2, with ultrasonic scaler, Group 3, with rotating root planing bur, Group 4, with Gracey curette plus rubber cup polishing, and Group 5, with ultrasonic scaler plus rubber cup polishing. Following root planing, the amount of tooth substance loss was evaluated by measuring the weight of the removed tooth substance and then 5 specimens ($5{\times}5{\times}2mm$) were randomly selected from the each group for roughness measurement. Root planed areas of each specimen were subjected to five measurements using the Profilometer and an average surface roughness values(Ra) for each group was obtained. Statistical difference for roughness values of each group was analyzed using oneway ANOVA and student t-test. For scanning electron microscopic(SEM) examination of root surface changes following root planing, 15 root surfaces of remaining 9 teeth were root planed and 3 specimens were randomly selected. The mean loss of tooth substance removed was Group 1, $7.0{\pm}1.09mg$, Group 2, $1.3{\pm}1.00mg$, Group 3, $5.8{\pm}1.72mg$, Group 4, $8.7{\pm}1.34mg$, and Group 5, $4.5{\pm}1.68mg$ following root palning, respectively. These results indicate that curette is effective instrument in the respect of diseased root substance removal. The average surface roughness values are following results : Group 1 and Group 4 were the smoothest surface ($Ra=0.34{\pm}0.06{\mu}m$, $Ra=0.34{\pm}0.04{\mu}m$, respectively) and Group 2 was the roughest surface ($Ra=2.09{\pm}0.06{\mu}m$). Statistical analysis of roughness values demonstrated a highly significant difference (P<0.05) between each experimental groups. However, no statistically significant difference in roughness values were observed between the Group 1 and Group 4. The results in this study suggest that curette and/or polishing procedure should be done after root planing with ultrasonic scaler and caution should be used with dia-mond-coated bur during routine root planing procedure.

• Journal of Periodontal and Implant Science
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• 제35권4호
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• pp.921-937
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• 2005

Mechanical and chemical methods are the two ways to treat the implant surfaces. By using mechanical method, it is difficult to eliminate bacteria and by-products from the rough implant surface and it can also cause the structural change to the implant surface. Therefore, chemical method is widely used in order to preserve and detoxicate the implant surface more effectively. The purpose of this study is to evaluate the effect of tetracylcline- HCl on the change of implant surface microstructure according to application time. Implants with pure titanium machined surface, SLA surface and $TiO_2blasted$ surface were used in this study. Implant surface was rubbed with sponge soaked in 50mg/ml tetracycline - HCl solution for $\frac{1}{2}$ min., 1min., $1\frac{1}{2}$ min., 2 min., and $2\frac{1}{2}min.$ respectively in the test group and with no treatment in the control group. The sponge was soaked in every 30 seconds. Then, the specimens were processed for scanning electron microscopic observation. Based upon the analysis of photographs by three dentists who are not related with this study, the results were obtained as follows; 1. In the pure titanium machined surfaces, the control specimen showed a more or less rough machined surface composed of alternating positive and negative lines corresponding to grooves and ridges. After treatment, machining line was more pronounced for the control specimens. but in general, test specimens were similar to control. 2. In the SLA surfaces, the control specimen showed that the macro roughness was achieved by large-grit sandblasting. Subsequently, the acid-etching process created the micro roughness, which thus was superimposed on the macro roughness. Irrespective of the application time of 50mg/ml tetracycline - HCl solution, in general, test specimens were similar to control. 3. In the $TiO_2blasted$ surfaces, the control specimen showed the rough surface With small pits. The irregularity of the $TiO_2blasted$ surfaces with 50mg/ml tetracycline - HCl solution was lessened and the flattened areas got wider after 1 minute.