應急患者移送體系 强化方案에 關한 硏究 : 시스템에 있어서의 構造·機能分析을 中心으로

학위논문(석사)--서울대학교 보건대학원 :보건학과 보건학전공,1997.Maste

purification and study of active center

학위논문(박사) - 한국과학기술원 : 생물공학과, 1989, [ ix, 108 p. ]Ampicillin acylase, which is known to have a novel substrate spectrum, was purified to homogeneity from Pseudomonas melanogenum by the crude extract preparation and chromatography with S-Sepharose, hydroxyapatite, CMcellulose C-52, and CM-Sepharose. The enyme was purified 8847-fold from the crude extract with a final recovery of 12\%. The molecular weight of the native enyme was calculated to be 146,000 by Protein PAK-300 sw HPLC chromatography. SDS-polyacrylamide gel electrophoresis revealed that the enzyme consisted of two identical subunits with a molecular weight of 72.000. The enzyme was a glycoprotein containing 13\% total carbohydrate, and its isoelectric point was 7.2. The optimal temperature for enzymatic activity was found to be 37$^\circ$C with a pH optimum of 6.0. The enyme catalyzed both synthesis and hydrolsis of ampicillin and hydrolysis of the ester bond of phenylglycinemethylester hydrochloride substrate. The substrate specificity showed that the enyme required a free amino group on the $\alpha$ -carbon of the acyl group. The chemical modification of purified ampicillin acylase by N-bromosuccinimide and diethlpyrocarbonate resulted in time-dependent inactivation of the enzyme. Both substrates ampicillin and 6-aminopenicillanic acid protected the enzyme against inactivation, suggesting that the modification occurred near or at the active site. Amino acid analyses and other data indicated that two histidyl residues per subunit molecule were essential for cataltic activity.한국과학기술원 : 생물공학과

반도체내의 불순물 접착확산

학위논문(석사) - 한국과학기술원 : 재료공학과, 1976.2, [ v, 55 p. ]This work introduces an approach to solve the problems encountered in semiconductor device fabrisation, difficulties of low concentration control, complexity and toxicity of traditional impurity diffusion processes. Doped silicon dioxide film as a diffusion source was formed through heat-treatment of mixture of dimethylpolysiloxane which was dissolved in $CCl_4$ and phosphorus pentoxide which was dissolved in ethanol, coated on the surface of a semiconductor wafer with a spinner. The heat-treatment temperature and time were 700$^\circ$C and 7 minutes, respectively. And the diffusions were performed at the temperature of 1000$^\circ$C, 1050$^\circ$C, 1100$^\circ$C, 1150$^\circ$C, and 1200$^\circ$C. As results, the spinning speed of 4000 RPM and the gas composition of 10\% $O_2$ - 90\% $N_2$ in the heat-treatment atmosphere were the best conditions to obtain the phosphorus-doped silicon dioxide film of about 2000\mbox{\AA} - thick as a diffusion source. And the total gas flow rate was at 1000 CC/min. The doped oxide gave constant surface concentration of $2\times10^{18}/cm^3$ for 10 hour diffusion time in the range of diffusion temperature of 1000$^\circ$C to 1200$^\circ$C in $N_2$ diffusion atmosphere. The diffusivities for surface concentration of $2\times10^{18}/cm^3$ were (6.75\pm1.75)\times10^{-15}cm^2/sec\;\;at\;\;1000^\circ{C},$ (3.26\pm0.39)\times10^{-14}cm^2/sec\;\;at\;\;1050^\circ{C},$$$(7.35\pm0.88)\times10^{-14}cm^2/sec\;\;at\;\;1100^\circ{C},$ $$(3.05\pm0.36)\times10^{-13}cm^2/sec\;\;at\;\;1150^\circ{C},$$ and $$(8.14\pm0.65)\times10^{-13}cm^2/sec\;\;at\;\;1200^\circ{C},$$ The most powerful advantages over the present method over traditional diffusion method are 1. the fact that it is easy to control very low surface concentration (down to $5\times10^{15}/cm^3$) and 2. uniformity of the impurity distribution The diffusivity for surface concentration of $5\times10^{15}/cm^3$ was $(1.35\pm0.27)\times10^{-13}cm^2$/sec at 1150$^\circ$C in $N_2$ di...한국과학기술원 : 재료공학과

고초균 에서 간염 바이러스 유전자의 Subcloning

학위논문(석사) - 한국과학기술원 : 생물공학과, 1985.2, [ [vii], 53 p. ]As the Hepatitis B Virus can not grow in cell culture at the present time and normally infects only man and apes, the only available viral source has been dependent on the limited amounts of material from the plasma of infected patients. Gene cloning of Hepatitis B Virus DNA into bacteria and eukaryotic cell lines was tried for large-scale production of Hepatitis B Virus DNA and viral antigens for diagnostic purpose. Although $\underline{Escherchia} \underline{coli}$ has been used as the host for expressing cloned genes, $\underline{Bacillus} \underline{subtilis}$ has been considered as an attractive candidate for the development of a cloning system with various advantages. Hepatitis B Virus DNA was inserted into a bacillus vector, pUB110, to check the possibility of cloning of Hepatitis B Virus DNA in $\underline{Bacillus} \underline{subtilis}$ and to express genes coding for viral proteins in $\underline{Bacillus} \underline{subtilis}$. Plasmid pUB110 (4.5Kb) was digested by EcoRI restriction enzyme and treated with bacterial alkaline phosphatase to inhibit the self-ligation of EcoRI-digested pUB110 plasmid. Hepatitis B Virus DNA (3.2Kb) eluted from EcoRI-digested pHBV213 plasmid which contains a single entire genome of Hepatitis B Virus in pBR 322 plasmid, was ligated with EcoRI-Bacterial alkaline phosphatase treated pUB 110 by T4 DNA ligase at 14℃ for 12 hours. $\underline{Bacillus} \underline{subtilis}$ B.D 170 cells (as a host cell) were protoplsated by treating lysozyme (1mg/ml) and the protoplasted cells were transformed with the above ligate mixture. The transformed cells were grown on regeneration media for 2 days. The sucessful transformation was checked by rapid plasmid isolation from the each transformant (Kanamycin-LB-Agar plate, 5ug/ml). Recombinant plasmid DNA which showed an increase in length on 1% agarose gel electrophoresis, was again digested with EcoRI enzyme and checked on 1% agarose gel whether Hepatitis B Virus DNA (3.2Kb) was ins...한국과학기술원 : 생물공학과