Methylmethacrylate와 n-Butylalcohol의 에스테르 교환반응에 관한 연구

鄭舜旭,朴根浩,孫秉淸,金忠一 弘益大學校 1988 弘大論叢 Vol.20 No.2

The transesterification reaction between methylmethacrylate and n-butyl alcohol was kinetically investigated in the presence of constant quantity of inhibitor and various metal acetate catalyst at 120℃. The quantity of n-butylmethacrylate produced in the reaction flask was measured by gas-chromatography, and the reaction rate was investigated by measuring of the quantity of the product the reaction under various catalysts. The transesterification was carried out in the first order reaction kinetics with respect to the concentration of methylmethacrylate and n-buty1 alcohol, respectively. The linear relationship was show between rate constant and absolute temperatures, and the activation energy of 14.7Kcal for the reaction with zinc acetate catalyst was calculated. The maximum reaction rate was appeared at the range of 1.5 to 1.6 of electro-negativity of metal ions.

Streptozotocin 유도 당뇨쥐에서의 Phospholipase A₂, Cyclooxygenase 활성과 Thromboxane 및 Prostacyclin합성

양정아,김성옥,최정화,곽오계,이순재,장현욱 영남대학교 약품개발연구소 1998 영남대학교 약품개발연구소 연구업적집 Vol.8 No.-

당뇨병에서의 혈전생성 기전에 관련된 주된 요인을 관찰코져 흰쥐를 4주간 사육한 후 streptozotocin(STZ)으로 당뇨를 유발한 후 6일째에 희생하여 당뇨쥐에 있어서의 phospholipase A₂ 활성변화에 따른 조직의 과산화적 손상과 혈소판 응집능 등의 변화를 관찰한 결과는 다음과 같다. 체중증가는 STZ를 투여한 후에는 STZ 투여군에서 현저하게 감소하였다. 식이섭취에 있어 STZ injection 후, DM군은 16% 증가하였다. 식이효율은 STZ injection 후 DM군은 정상군에 비해 유의적으로 감소하였다. 혈청 중의 총 지질과산화물가는 정상군에 비해 DM군은 2.5배 높았다. HDL 중의 TBARS는 정상군에 비해 DM군은 약 1.6배 정도 높았고 LDL 중의 TBARS는 정상군에 비해 DM군에서 4.8배의 높은 증가를 보였다. 혈소판 phospholipase A₂ 활성은 DM군은 정상군에 비해 42% 증가하였다. 혈소판 cyclooxygenase 활성은 정상군에 비해 DM군이 2배 정도 높은 수준이었다. 혈소판 중의 TXA₂ 농도는 정상군과 비교하여 DM군에서 169%로 현저하게 높았고 대동백 PGI₂의 농도는 정상군에 비해 DM군은 낮은 수준을 보였으며 대동맥 PGI₂와 혈소판 TXA₂의 비는 DM군에서 정상군에 비해 55% 낮았다. 결론적으로 STZ 유발 당뇨쥐에 있어서는 혈청 지질과산화물 수준의 증가와 더불어 phospholipase A₂ 활성이 증가되었으며 따라서 cyclooxygenase가 유도하는 AA cascade 활성화에 의해 TXA₂ 생성증가 및 PGI₂/TXA₂ ratio의 감소가 관찰되었다. 이러한 결과는 당뇨병 질환에서 나타나는 동맥경화증, 심혈관계 질환 등의 여러 혈관계의 병리적 현상들이 당뇨 상태에서의 지질대사 이상으로 인한 지질과산화물의 증가와 그의 독성으로 인한 여러 혈소판 관련 인자들의 활성화와 밀접하게 연관되어 나타나는 것을 시사하는 것이라 하겠다. The relation between lipid peroxidation and thrombotic reaction were investigated in streptozotocin (STZ)-induced diabetic rats. Sprague-Dawley male rats weighing 100±10gm were randomly assigned to normal and STZ-induced diabetic group(DM). Diabetes was experimentally induced by intravenous injection of 55mg/kg of body weight of STZ in citrate buffer(pH 4.3) after 4 weeks feeding of basal diet. Animals were sacrificed at the 6th day of diabetic states. Body weight gains were lower in diabetic group after STZ injection. Serum levels of thiobarbituric acid reacting substances(TBARS) that were markedly increased in DM group compared with of normal group. TBARS levles of HDL and LDL were similar patterns to total TBARS of serum. Activities of platelet phospholipase A₂(PLA₂) were higher in diabetic group than those of normal group. Activities of platelet cyclooxygenase were 106% in DM group than normal group. Platelet thromboxane A₂(TXA₂) formation was increased in DM group than normal group. Production of aortic prostacyclin(PGI₂) was lower in diabetic group than that of normal group. PGI₂/TXA₂ ratios were decreased by 55% in DM groups than those of normal group. The present results indicate that STZ-induced diabetic rats are more sensitive to oxidative stess which leads to acceleration of lipid peroxidation and platelet aggregability. In conclusion, accelerating effect of lipid peroxidation and thrombogenesis in diabetic state is regarded to be resulted from enhancement of PLA₂ activity and arachidonic acid metabolism, inhibition of antiaggregating agent and aortic PGI₂ formation.

식도를 포함한 전위장관을 침범한 전이성 악성 흑색종 1예

최정영,김준기,신성하,고영춘,조상욱,서강석,강명원,임연근,여향순,김경수 全南大醫大 2001 전남의대학술지 Vol.37 No.1

임시 금관용 비귀금속 합금의 전기화학적 부식에 관한 연구

김정욱,임범순,김철위 서울대학교 치과대학 치과생체재료학교실 1994 치과생체재료학 논문집 Vol.2 No.1

The employment of base metal alloys as substitutes of gold alloys is gaining increasing popularity. The corrosion of dental base metal alloys was recoginzed due to the nature of the oral environment. Corrosion of dental meterials in the mouth can affect the mechanical properties, esthetic properties and efficiency of dental metallic restorations, and has great influence upon the local and systemic health of the patient. The researches on the harmful effect of dental base metal alloys and their corrosin products on the human body are progressed actively. The electrochemical corrosion studies in vitro were done to predict the corrosion behavior of dental alloys in vivo, but the result may be different depending on the corrosion environments. As the normal range of inorganic ions and organic molecules in saliva is various with patient, in vivo corrosion behavior may be different depending on the patients. It may result in interindividual differences on corrosion behavior even though the restorations were made of the same alloy. The purpose of this experiment was to evaluate the difference in corrosion behavior of dental base metal alloys for temporay crown when the concentrations of organic compounds in the artificial saliva were varied. The materials used in this study were the modified Fusayma's artificial saliva (pH. 6.7), and the artificial saliva with organic compound additions such as polyacrylic (5㎖/1), acetic (5㎖/1), citric (2 g/l) and lactic acid (5㎖/1). Totalof four kinds of dental base metal alloys for temporary crown; two kinds of stainless stel alloys (SSP: 17% Cr-12% Ni-67% Fe, INC : 17% Cr-9% Ni-68% Fe), nickel-chromium alloys (APC : 90% Ni-5.5% Ni-4.5% Cu), and aluminium alloys (APC : 99% Al-0.5% Fe-0.1% Cu), were studied. Specimens were 0.2㎜ thick and had surface area of 1 ㎠ (or 0.25㎠). The specimens were connected to the copper wire and mounted in the self-curing acrylic resin. Embedded specimens were polished with the silicon caarbide papers up to # 2,000, then ultrasonically cleaned, and dried by clean air. After the surface oxide layer of specimens was removed at-1,500㎷(SCE) immersed in the vairous meterials, the corrosion behaviors of the specimens were studied by electrochemical hysteresis technique involving potentiodynamic polarization from - 1,000 ㎷ to + 1,000 ㎷ and reverse polarization back to -1,000 ㎷ with the scanning rate of 2㎷/sec in the aeration environment. The current density change of specimen was recorded X-Y poltter via logarithmic onverter. From the experiment, the following results werre obtained : 1. For the stainless steel specimen SSP, passivation film was formed in the artificial saliva and in the artificial saliva with organic components added electrolytes. SSp showed the good corrosion resistance in experimental electrolytes. Addition of organic components to the artificial saliva showed only minor effect. 2. The formation of passivation film on INC was unstable. It was observed that the corrosion resistance on INC was lower than that of SSP. 3. In the nickel-chromium alloys specimen APC, the possibility of passivation film formation was lower than in the stainless steel specimens SSP and INC. It causes lower corrosion resistance than that of SSP and INC. 4. In the aluminium alloys specimen, ATP, showed the dissolution reaction in all experimental electrolyes such as artificial saliva and artificial saliva with polyacrylic, acetic, citric, and lactic acid added.

Dimethylphthalate와 Ethyleneglycol의 에스테르 交換 反應에 關한 硏究(2)

孫秉淸,鄭舜旭 弘益大學校 1985 弘大論叢 Vol.17 No.2

The transesterification reaction between dimethylphthalate and ethyleneglycol was kinetically investigated in the presence of various metal chloride catalysts at 180℃. The reaction was followed by the measurement of distilled methanol from the micro measuring cylinder. The transesterification reaction was first-order kinetics with respect to the concentration of dimethylphthalate, ethyleneglycol and catalyst. From the examination of relationship between rate constant and reciprocal absolute temperature, the activation energy has been calculated as 22.62 Kcal with cupric chloride catalyst, 32.26 Kcal with zinc chloride catalyst.+the highest reactivities were found for electronegativity values between 1.4∼1.7.

Cyan Coupler의 합성과 발색현상에 관한 연구

金榮燦,鄭舜旭,孫秉淸 弘益大學校 科學技術硏究所 1995 科學技術硏究論文集 Vol.6 No.-

In this paper, cyan coupler was prepared by the reaction of 2-amino-4.6-dichloro-5-me-thylphenol with 2,4-ditirtiarypentyl-phenoxy-butyroyl chloride in the presence of pyridine. The product was identified by using various analytical tools such as melting point. Elemental analyzer. IR spectrophotometer. UV-Vis spectrophotometer Mass Spectrometer. The reaction of cyan coupler with CD-3(color development agent) was shown cyan color.

Langmuir-Blodgett 초박막의 전기적 특성

최병호,김성진,정순욱 金烏工科大學校 1998 論文集 Vol.19 No.-

Ultrathin film of 100Å-order is fabricated by Langmuir-Blodgett technique. By measure of UV-vis spectra and capacitance, deposition status was confirmed together with the thickness of natural oxidized aluminum film inside a device and dielectric constant of (N-docosyl pyridinium)-TCNQ(1:2) complex. The conductivity of this film measured by the direction of either vertical or horizontal axis is results in a quite different value.

소아에서 출혈을 동반한 단일 연소성 용종의 내시경적 절제술

김준기,조상욱,신성하,고영춘,최정영,서강석,강명원,임연근,여향순,김경수 全南大醫大 2001 전남의대학술지 Vol.37 No.3

Langmuir-Blodgett 法을 위한 (3-Alkyl Benzimidazolium)-TCNQ(1:1) 錯物의 合成

孫秉淸,閔丙卨,鄭舜旭 弘益大學校 科學技術硏究所 1993 科學技術硏究論文集 Vol.3 No.-

특발성 경련질환으로 오인된 원발성 부갑상선기능저하증 1례

신성하,최정영,김준기,고영춘,조상욱,김순호,임중규 全南大醫大 2001 전남의대학술지 Vol.37 No.1