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Cytotoxicity and L-Amino Acid Oxidase Activity of Animal Venoms
Ahn, Mi-Young,Lee, Byung-Mu,Kim, Yeong-Shik The Pharmaceutical Society of Korea 1997 Archives of Pharmacal Research Vol.20 No.1
The cytotoxicity of animal venoms (snakes, insects and marine animals) was measured against SNU-1 (stomach cancer cells) by dye uptake assay (MTT method). And also L-amino acid oxidase (AAO) activity of the venoms was compared. Among them, the venom from Ophiophagus hannah (king cobra) showed a strong AAO activity as well as a high potent cytotoxicity. Cytotoxic protein having a AAO was then partially purified by HPLC-GPC and two fractions (Fr. I and Fr. II) were collected. The $IC_{50}$ values of Fr. I and Fr. II were 0.19 ${\mu}g/ml$ and 1.36 ${\mu}g/ml$, respectively. The results suggested that the cytotoxicity of king cobra venom may be due to its AAO activity.
DMBA로 유발한 Mouse 피부암에 대한 Astaxanthin이 함유된 난황의 항암효과
이상호,박철우,이영춘,최의성,김무남,하영래,Lee, Sang-Ho,Park, Cheol-U,Lee, Yeong-Chun,Choe, Ui-Seong,Kim, Mu-Nam,Ha, Yeong-Rae 한국환경성돌연변이발암원학회 1998 한국환경성돌연변이·발암원학회지 Vol.18 No.1
Anticarcinogenic activity of astaxanthin-containing egg yolks (designate AEY) was investigated for 7,12-dimethylbenz[a]anthracene (DMBA)-induced two stage mouse epidermal carcinogenesis. Female ICR mouse (6-7 weeks of age) were house in a humidity-and-temperature-controlled facility and subjected to feed and water ad libitum. AEY (10 mg/0.2 ml acetone) was painted on the back of mice 7 days, 3 days and 5 min before DMBA treatment (50 nmole/0.2 ml acetone). One week later after DMBA treatment, 6 ${\mu}g$ tetradecanoyl 12-phorbol 13-O-acetate (TPA) dissolved in 0.2 ml acetone was applied on the mouse twice weekly over a period of 22 weeks. No sample was given to control mice. Control egg yolk (CEY) and astaxanthin-containing oil (designate AO) from Phaffia rhodozyma were used as positive controls. Mouse treated with AEY exhibited 10 tumors per mouse whereas control mouse exhibited 15 tumors per mouse, the fact that 33% reduction of tumor per mouse by AEY treatment. Tumor incidence was also reduced to 15% by AEY treatment when compared to that of control group. Such effects were also seen in CEY and AO treatment groups, but leaser extent. AO gave reduction of food intake and body weights relative to those of AEY and CEY, indicating toxicity of AO. These results suggest that AEY exhibits anticarcinogenic activity for DMBA-induced mouse epidermal carcinogenesis.
내장형 펌핑 커패시터를 사용한 TFT-LCD 구동 IC용 전하펌프 설계
임규호,송성영,박정훈,이용진,이천효,이태영,조규삼,박무훈,하판봉,김영희,Lim, Gyu-Ho,Song, Sung-Young,Park, Jeong-Hun,Li, Long-Zhen,Lee, Cheon-Hyo,Lee, Tae-Yeong,Cho, Gyu-Sam,Park, Mu-Hun,Ha, Pan-Bong,Kim, Young-Hee 한국정보통신학회 2007 한국정보통신학회논문지 Vol.11 No.10
본 논문에서는 TFT-LCD 구동 IC 모듈의 소형화 측면에서 유리한 DC-DC 변환기 회로인 펌핑 커패시터 내장형 크로스-커플드 전하펌프(Cross-Coupled Charge Pump with Internal Pumping Capacitor) 회로가 새롭게 제안되었다. VGH 및 VGL 전하펌프 각각의 입력단과 전하 펌핑 노드를 연결하는 NMOS 및 PMOS 다이오드를 두어, 초기 동작 시 전하 펌핑 노드를 서로 같은 값으로 프리차지하여 대칭 적으로 전하 펌핑을 하도록 하였다. 그리고 첫 번째 전하 펌프의 구조를 다르게 설계하여 펌핑된 전하가 입력단으로 역류되는 현상을 방지하였다. 또한, 펌핑 클럭 구동 드라이버의 위치를 펌핑 커패시터 바로 앞에 두어 기생 저항으로 인한 펌핑 클럭 라인의 전압강하를 방지하여 구동능력을 향상 시켰다. 마지막으로 내장형 펌핑 커패시터를 Stack-MIM 커패시터를 사용하여 기존의 크로스-커플드 전하펌프 보다 레이아웃 면적을 최소화하였다. 제안된 TFT-LCD 구동 IC 용 전하펌프 회로를 $0.13{\mu}m$ Triple-Well DDI 공정을 사용하여 설계하고, 테스트 칩을 제작하여 검증하였다. A cross-coupled charge pump with internal pumping capacitor, witch is advantages from a point of minimizing TFT-LCD driver IC module, is newly proposed in this paper. By using a NMOS and a PMOS diode connected to boosting node from VIN node, the pumping node is precharged to the same value each pumping node at start pumping operation. Since the lust-stage charge pump is designed differently from the other stage pumps, a back current of pumped charge from charge pumping node to input stage is prevented. As a pumping clock driver is located the font side of pumping capacitor, the driving capacity is improved by reducing a voltage drop of the pumping clock line from parasitic resistor. Finally, a layout area is decreased more compared with conventional cross-coupled charge pump by using a stack-MIM capacitors. A proposed charge pump for TFT-LCD driver IC is designed with $0.13{\mu}m$ triple-well DDI process, fabricated, and tested.
아르곤 레이저와 가시광선에 의한 중합 후의 수복재와 치아와의 전단결합강도 비교
고영무,계기성,황호길 대한치과기재학회 1999 대한치과재료학회지 Vol.26 No.3
Previous preliminary researches have shown that argon laser will polymerize dental photo-activated resin materials. The purpose of this study was to compare the shear bond strength of dental restorative materials to teeth polymerized with an argon laser and visible light. An argon laser operating at 0.5W of power and a conventional visible light polymerization unit were used in testing shear bond strength between restorative materials and teeth. Specimens were prepared according to accepted standards for testing. A universal testing machine was used to shear bond strength 5㎜/min crosshead speed. In case of argon laser, exposure time were 10 second, whereas in case of visible light, exposure time were 40 second. The results showed that shear bond strength of F2000 Compomer(3M) polymerized with argon laser were superior to those of polymerized with visible light and there is significantly different(p<0.05). Whereas, in case of both OptiBond FL(Kerr) and Spectrum TPH(Dentsply) shear bond strength of composite resins polymerized with argon laser were slightly inferior to those of polymerized with visible light, but there is no significant difference(p>0.05). This study was supported by Research Funds from Chosun University,1996.
고영무,최한철,강성남,강희영,이승윤 대한치과기재학회 1998 대한치과재료학회지 Vol.25 No.3
A gallium based alloy(GA) that was developed as a substitute for dental amalgam was investigated for electrochemical corrosion behavior in 4 kinds of electrolytes(1% lactic acid, 0.05% HCI, Modified Fusayama's artificial saliva, and 0.9% NaCl). The related corroded microstructure were examined and microanalyses were conducted using ICPES. Polarization tests were conducted by scanning from -1,500㎷ to 1,000㎷(vs.SCE) at 75㎷/min. The obtained results were as follows: 1. GA showed wide passivation area next to SYB in artificial saliva, suggesting good stability. 2. The amounts of Sn, Cu released from GA were similiar to those of CAV, and decreased in the order of KAT, SYB. 3. All of specimens were observed pits at the area of pores in electrolytes containing chloride ions, and forming much corrosion products in 1% lactic acid and artificial saliva after corrosion test. 4. From the surface analyses of XRD, GA showed much corosion products containing gallium at the surface after corrosion test. In conclusion, the corrosion resistance of GA was lower than that of SYB and similiar to that of CAV and KAT.
고영무,최한철,정재헌,정효수,최성욱 대한치과기재학회 1999 대한치과재료학회지 Vol.26 No.4
In order to investigate the various properties of dental magnetic materials studies on corrosion behavior, decreasing rate of magnetic flux density, amount of elements released, mean average surface roughness values and the changing of mean surface microhardness values for dental application were done. To increasing the corrosion resistance of dental magnetic materials, surfaces of Sm-Co and Nd-Fe-B based magnetic materials were plated with gold(Au), platinum(Pt), titanium(Ti), chromium(Cr) and cobalt(Co), and then electrochemical corrosion test were performed in 4 kinds of electrolyte solution(0.9% NaCl, 1% lactic acid, 0.05% HCl and modified Fusayama's artificial saliva). The results were as follows: 1. In Sm-Co and Nd-Fe-B based magnetic materials, the pitting corrosion of experimental group was higher than that of the control group, the experimental group was less corrosive than control hroup. 2. The amount of elements released from experimental group was more significantly decreased than that of control group. 3. Decreasing rate of magnetic flux density of experimental groups was significantly lower than that of control group after corrosion test. 4. The mean average surface roughness value of one(Sm-Co based magnetic materials not plated) of the control group was much increased in modified Fusayama's artificial saliva after first corrosion but that of the other(Nd-Fe-B based magnetic materials not plated) was much increased in 0.05% HCl solution. 5. The decreasing rate of surface microhardness values of experimental groups were lower than that of control group after corrosion, 6. Intergranular corrosion started first from the grain boundary of the control group and they advanced gradually to general corrosion, and the pitting corrosion occurred locally at area of existing pits in experimental group.
전자빔 진공증착을 이용한 치과용 임플란트재의 표면 전처리법에 따른 HA 코딩효과
고영무,최한철,최낙찬 大韓齒科器材學會 2002 대한치과재료학회지 Vol.29 No.4
The dental implant materials require good mechanical properties, such as fatigue strength, combined with a high resistance to corrosion. For increasing fatigue resistance and delaying onset of stress corrosion cracking, shot-peening has been used for over 50 years to extend service life of metal components, However, there is no information on the electrochemical behavior of shot-peened and hydroxyapatite(HA) coated Ti-6Al-4V alloys. To increase fatigue strength, good corrosion resistance, and biocompatibility, the electrochemical characteristics of Ti/TiN/HA coated and shot-peened Ti-6Al-4V alloys by EB-PVD have been researched by various electrochemical method in 0.9%NaCl The coated layer and surface showed the formation of dense and uniform surface in the case of TiN/HA and Ti/TiN/HA film coated samples. The hardness of shot-peened Ti-6Al-4V alloys(SPA) increased as SP treatment time increased. Electrochemical measurements showed that, in the case of shot-peened Ti-6Al-4V alloys, the corrosion and pitting potential increased due to the SP induced removal of defects, such as inclusion, scratch, and pore on the surface, whereas passivation and active current density decreased as the SP time increased. For the HA coated samples, pitting and repassivation potential increased in the order of Ti/TiN/Ha > TiN/HA > Ti/HA > HA coated SPA. Results suggest that the best pitting corrosion behavior is shown by Ti/TiN/HA coated SPA with a fatigue strength and biocompatibility.
인공타액에서 치과용 자성재의 전기화학적 부식에 대한 스퍼터링 도금의 효과
고영무,김경남,김광만 대한치과기재학회 1997 대한치과재료학회지 Vol.24 No.2
Dental magnetic materials have been applied to removable prosthetic appliances, maxillofacial prostheses, obturator and dental inplant but they still have some problems such as low corrosion resistance in oral environments. To increase the corrosion resistance of dental magnetic materials, surfaces of Sm-Co and Nd-Fe-B based magnetic materials were plated with gold(Au), platinum(Pt), titanium(Ti), chromium(Cr) and cobalt(Co), and then electrochemical corrosion test were performed in modified Fusayama's artificial saliva. From this study, corrosion behavior, decreasing rate of magnetic flux density, amount of elements released, mean average surface roughness values and the changing of mean surface microhardness values were measured comparing with control group of non-sputtered plating magnetic materials. The results were as follows : 1. In Sm-Co and Nd-Fe-B based magnetic materials, the pitting corrosion of control group was lower than that of the experimental group, the control group was more corrosive than experimental group. 2. The amount of elements released from experimental group was more significantly decreased thatn that of control group(p<0.05) 3. Decreasing rate of magnetic flux density of experimental groups was significantly lower than that of control group after first corrosion, but it was increased after second corrocion in all tested cases. 4. The mean average surface roughness value of control group were not different from those of experimental group. The mean average surface roughness value of both Sm-Co and Nd-Fe-B based magnetic materials were much increased in modified Fusayama's artificial saliva after corrosion. 5. The mean average surface microhardness values of control group were not different from those of experimental group before corrosion. After corrosion, the same valuse of contral group were more decreased that those of experimental group, and the decreasing rate of surface microhardness values after second corrosion was higher than that of values after first corrosion. 6. Intergranular corrosion started first from the grain boundary of the control group and they advanced gradually to general corrosion, and the pitting corrosion occurred locally at area of existion pits in experimental group. In conclusion, it is considered that the corrosion problem of dental magnetic materials could be solved to some extent by sputtered plating with several metals on the surface of dental magnetic materials.
Dentacolor Resin System의 색안정성 및 물흡수도에 관한 연구
고영무,정재헌,최유석 大韓齒科器材學會 1995 대한치과재료학회지 Vol.22 No.2
The purpose of this study was to measure the color stability and water sorption of Dentacolor resin system at various time intervals over 6 week period. Ten, 20 x 1mm discs of the resin specimen were prepared according to ADA specification No.27 and cured with a photo-polymerization equipment(Dentacolor XS and Unilux AC). The color parameters of L*, a*, b* were measured with a computerized colorimeter(Hunter Associates Laboratory Inc., USA) in the transmittance mode. The total color change(ΔE) occurred during two different time periods was calculated using the following equation: ?? The amount of water sorption measurements was done in accordance with ADA specification No.27 for one week in distilled water at 37 ±1℃ and then stored extended up to 6 weeks. The obtained results were as follows : l. At first week, total color difference(ΔE) value of Dentacolor resin system was 1.430 ±0.664. 2. It was found that the range of total color difference(ΔE) of Dentacolor resin system was between 0.5∼1.430 for 6 weeks. 3, The amount of water sorption for one week was 0.30 ±0.119mg/cm²and it was lower than the 0.7mg/cm²/week for type Ⅱ composites in ADA specification No.27. 4. The amount of water sorption of Dentacolor resin system after 6 weeks was much more than its amount of water sorption of the first week, but it was not significant difference(p>0.05).
아말감과 금합금 및 니켈-크롬합금의 접촉시 부식에 관한 연구
고영무,계기성 大韓齒科器材學會 1993 대한치과재료학회지 Vol.20 No.2
The purpose of this study was the effect of area ratio, the difference of electrolyte between artificial saliva and 0.9% NaCl solution and that of corrosion rate on amalgam in contact with the dental casting gold and the nickel-chromium alloy by measuring the amount of elements released in the electrolyte using Inductively Coupled Plasma Emission Spectroscopy (ICPES). After each amalgam alloy and Hg was triturated as the direction of the manufacturer by means of the mechanical amalgamator, the triturated mass was inserted into the disk shaped stainless steel mold 5mm in diameter and 4mm thick and condensed by using routine manner. The excess amalgam on the surface was removed by razor blade. Twenty-four hours after condensation, samples were removed from the molds and the standard surface preparation was routinely carried out. The specimens of casting gold and nickel-chromium alloy were all made from wax patterns prepared in a matrix with the same shape(30×10×1mm). Investing and casting were done according to the recommendations of each manufacturer. These specimens were ground with silicone carbide papers(#600) and polished. The polished samples were ultrasonically cleaned, rinsed in acetone solution and dried. Amalgam plugs was inserted into the casting gold and nickel-chromium alloy plates. The dental casting gold and nickel-chromium alloys were stored at 37℃±1℃ in glass beaker for 12 weeks in contact with a high copper amalgam, area relations 6 : 1 and 6 : 3, in an electrolyte of artificial saliva and 0.9% NaCl solution. The solutions were renewed each 4 weeks and analyzed for Cu, Zn, Sn, Hg, and Ag in an Inductively Coupled Plasma Emission spectroscopy (ICPES). From the experiments, following results were obtained : 1. In the case of amalgam in contact with dental casting gold alloy in the 0.9% NaCl solution, the amount of the copper released was greatest. 2. Generally, a corrosion reaction in the dental casting gold alloy in contact with amalgam was more severe than in the nickel-chromium alloy and in the acrylic resin. 3. The amount of elements released in the 0.9% NaCl solution was much more than in the artificial saliva solution and pH values of both of solutions were increased from 5.8 to 8.5. 4. The tendency for tin(Sn) to be released from the amalgam was greatest during the first 4 weeks and decreased with time elapsed, and silver(Ag) was greatest from the beginning of 9 weeks. 5. The amount of the metal elements released per ㎠ amalgam was larger for the 1 : 6 than for the 3 : 6 amalgam/gold ratio. 6. In the case of dental casting nickel-chromium alloys in contact with amalgam, the amount of another metal elements released was decreased due to severe releasing of nickel. 7. The corrosion rate of the amalgam was more influenced by the type of electrolyte than by the type of the dental casting alloy.