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.

치과용 자성재의 안정성 개선에 관한 연구 : I. 치과용 자성재의 전기화학적 부식에 대한 스퍼터링 도금의 효과 I. Effects of Sputtered Film Deposition on the Electrochemical Corrosion of Dental Magnetic Materials

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.

Vita Lumin Shade Guide와 Vita Shade Resin Composite 간의 색깔차이

고영무,최한철,최충국 대한치과기재학회 1996 대한치과재료학회지 Vol.23 No.2

The Purpose of this study was to evaluate the possibility of using Vita Lumin shade guide to select shades of composite resin. Vita Lumin shade guide, such as four kinds of composite resin; Z100(3M), Prisma T.P.H.(Caulk/Dentsply), Tetric(Vivadent), Dentacolor resin system(Kulzer Co.) and shade guide which is supplied by the manufacturer were used in this study. The four kinds of shade which are poplar were used; A2,A3,B3, and D3, but, in case of Prisma T.P.H. we chose A3.5 instead of A3 because it does not have A3 shade. The shade guide from the manufacturer and Vita Lumin shade guide are ready made but we made 6 samples od each composite resin which size are 10±1mm in diameter, 2.0±0.1mm in thickness, and then composite resin were light cured for 40 sec. In case of the Dentacolor resin system, we put them into the Dentacolor XS unit then light cured 180 sec. according to manufacturer's instruction. After the curing, we eliminated the samples from the molds and stored them in distilled water for 48 hours. Using the Colorimeter(Hunter Inc, USA) and examining the value of L*a*b* for three times, we calculated their mean values. The resulte were as follows; among all 4 kinds of composite resin which are produced by same shade, shade guide which are supplied by same shade vs. composite resin, there are big differences more than expected. In the view of the result of this study, there is a little problem with the use of the Vita Lumin shade guide and the shade guide which is supplied by munufacturer. Therefore, we conclude that we need more accurate the cuatomized shade guide. This study was supported by research funds from Chosun university.

최신 본딩재

고영무 대한치과기재학회 2000 대한치과재료학회지 Vol.27 No.4

최과 교정용 스테인리스 강 선재의 신선 가공법이 내식성에 미치는 영향

고영무,모웅남,최한철 大韓齒科器材學會 2003 대한치과재료학회지 Vol.30 No.1

The dental orthodontic wire requires good mechanical properties, such as elastic strength, combined with a high resistance to corrosion. For increasing elastic strength and delaying onset of stress corrosion cracking, drawing methods(one-step and two-step drawing) have been used in this study to extend service life of metal components, However, there is no information on the electrochemical corrosion behavior of drawn wires for orthodontics. To increase elastic strength, good corrosion resistance, and biocompatibility, the electrochemical characteristics of drawn wire have been researched by field emission scanning microscope and potentiodynamic method in 0.9% NaCl solution. The one-step drawn wire showed the formation of rough surface. The hardness and tensile strength of two-step drawn wire increased. Electrochemical measurements showed that, in the case of two-step drawn wire, the corrosion resistance and pitting potential increased compared with two-step drawn wire due to the drawing induced small surface roughness, such as scratch, whereas passivation and active current density decreased as the reduction in area for drawing increased.

전해액의 종류에 따른 치과용 금합금의 전기화학적 부식 거동

고영무,최성욱 대한치과기재학회 2001 대한치과재료학회지 Vol.28 No.1

The effect of different electrolytes on the results from potentiodynamic polarization corrosion testing was studied for 3 different dental gold alloys. The obtained results were as follows. 1.From the potentiodynamic curves the corrosion behavior of natural saliva was similar to that of Darvell's and Hay & Hartles' artificial saliva solution. 2.Fusayama's and Tani & Zucchi's artificial saliva solutions were more corrosive than natural saliva, Darvell's and Hay & Hartles' artificial saliva solution. 3.The corrosion behaviors of Fusayama's and Tani & Zucchi's artificial solutions were very similar in case of Cast-1 and Cast-3. 4.3 kinds of all alloys showed that the amount of gold released was highest in Fusayama's artificial saliva solution. In conclusion, the corrosion behavior of natural saliva was similar to Darvell's and Hay & Hartles' artificial saliva and Fusayama's artificial saliva solution was the more corrosive than any other solutions. But the effect of different electrolytes the corrosion behavior of high gold alloys was not different highly.

티타늄 상에 강유전성 barium titanate 박막 형성과 분극처리에 의한 유사체액 내에서의 calcium phosphate 생성 증진

박영준,이용렬,황규석,김은주,임용무,이기헌 대한치과기재학회 2001 대한치과재료학회지 Vol.28 No.2

This study was performed to fabricate a ferroelectric barium titanate (BaTiO₃, BTO) thin film on Ti substrate and to evaluate the effect of poling treatment for the improvement of calcium phosphate (Ca-P) formation. BTO thin-film was spin-coated on Ti substrate by dipping-pyrolysis technique using coating sol obtained by mixing Ba-naphthenate and Ti-naphthenate as starting substances. Pre-heating temperature of the BTO thin film was performed at 500℃ because organic-solvent was completely volatilized without any crystal growth, and the final heat treatment was performed at 600, 650, 700, 750, 800, 850℃, respectively. By repeating the coating and pre-heating procedure gor 20 times, homogeneous thin film of 0.7㎛ thickness could be fabricated, and it performed well during the poling treatment without breakdown. The final heating treatment of the BTO thin film at 750℃ produced a homogeneous crystalline structure without heterogeneous TiO₂formation, which was confirmed by field emission scanning electron microscope (FE-SEM) and X-ray diffraction analyser (XRD). An average grain size of 20∼30 ㎚ were confirmed by SEM observation. The final heat-treated BTO thin-films were polarized (Ep = 5 V/㎛) from 160℃ to 25℃ in heating chamber for 2 h. The negatively poled BTO thin film (N-BTO), non-poled BTO thin film (BTO), Ti substrate (Ti), and 600℃ heat-treated Ti (Ti-O) were immersed in SBF and Eagle's MEM solution for 15 days at 37℃. After the immersion period, the morphological and compositional changes of the surfaces were investigated using a FE-SEM and an energy dispersive X-ray spectrometer (EDX). After immersion in simulated body fluid (SBF), sodium chloride (Nacl) crystals were formed on Ti, Ti-O, and BTO surfaces due to anion adsorption (Cl), while Ca-P crystals were formed on N-BTO surfaces. We assumed that rapidly adsorded cations (Ca²□ ions) on the negatively charged surface at the initial stage acted as nuclei for the formation of Ca-P crystals. In MEM, sodium chloride (NaCl) was formed on Ti, and Ca-P layer including NaCl was formed on Ti-O. Weak and sparse Ca-P layers were formed on BTO, while thick, homogeneous, and dense Ca-P layer was formed on N-BTO, which was confirmed by FE-SEM and EDX. These results demonstrated that introducing a N-BTO on Ti is an effective method for the improvement of Ca-P formation in SBF and MEM. In conclusion, negatively charged ferroelectric BTO thin-film on Ti would improve the possibility of implant osseointegration.