Transthyretin의 Glutathione 자동산화 촉진작용

박종근,정신,김재휴,김수한,강삼석,이제혁,안봉환 대한신경외과학회 1994 Journal of Korean neurosurgical society Vol.23 No.8

When reduced glutathione(GSH) was incubated at neutral pH and at 37°, its concentration decreased slowly with formation of oxidized glutathione(GSSG). Autooxidation of GSH was accelerated by Cu^(2+) and Hg^(2+), but not by other common mono-, di-, and tri-valent cations. Transthyretin was found to stimulate autooxidation of GSH in the presence or absence of Cu^(2+) and Hg^(2+). EDTA inhibited perfectly the autooxidation of GSH regardless of the presence of transthyretin. The stimulating activity of transthyretin was maximal at pH 7.0, declining progressively with increase or decrease of pH from 7.0. Sulfhydryl-blocking agents such as p-hydroxymercuribenzoic acid and Nethylmaleimide markedly inhibited the stimulating activity of transthyretin. Transthyretin stimulated autooxidation of other sulfhydryl compounds such as clithiothreitol and cysteine. However, it did not show a significant effect on autooxidation of sulfhydryl group of egg albumin and eye lens proteins. And transthyretin did not cause any oxidative change to thyroxine(T₄), 3, 5, 3Ltri iodo thyronine(T₃) and 3, 3: 5~triiodothpnine(rT₃) bound to it in the presence of GSH and Cu^(2+). The above results suggest that transthyretin may play a role in regulation of oxidized status of sulfhydryl groups in blood plasma and cerebrospinal fluid

상온재생 유화아스팔트 개질 혼합물의 배합방법 및 특성에 관한 실험적 연구

박승범,권혁준,이봉춘,김선용 충남대학교 산업기술연구소 1999 산업기술연구논문집 Vol.14 No.2

Recently, the quantities of waste asphalt concrete at construction sites have much increased greatly, but maintaining a filling-up and final disposal place is a difficult problem. Therefore, we are faced with a worsening environmental problem brought about present illegal measures. One of the most effective recycling method is cold recycling. This method will satisfies treatment and recycling of construction waste is a very important question in the preservation of environmental and natural resources. So, in this paper, we dealt cold recycling modified mixtures using emulsified asphalt to concern the effect of adding reclaimed asphalt concrete 30, 40, 50%, and using SBR Latex for modified mixtures.

충주 지역에서 10년간 급성심근경색의 임상관찰에 대한 연구

박봉안,류하근,이종혁,김인숙,류주성,유재등,이용구,문언수,김형수 건국대학교 의과학연구소 2001 건국의과학학술지 Vol.11 No.-

Background: The current treatments of acute myocardial infarct(AMI) Include noninvasive method using thrombolytics and invasive methods such as primary percutaneous transluminal coronary angioplasty(PTCA) and coronary artery bypass graft(CABG)surgery. Although there are many studies comparing the effectiveness of noninvasive and invasive methods, when large clinical centers, 20% of totar hospitals, were excluded, most middle-sized hospitals lacked personnels and facilities for the invasive methods. Thus they opted for the noninvasive methods. Therefore, in this study, the clinical characteristics of AMI patients and the results of thrombolytic & conservative treatment were observed. Method: 137 patients with acute myocardial infarct, who visited KonKuk University Medical Center, ChoongJu Hospital during Sept. 1990 to Sept. 1999 were analysed retrospectively using medical records. Result: The sexual compositions of patients were 63.5% male, and 36.5% female. The mean age for male patients were 56±12.9, and for female patients 68.7±9.6 (p<0.05). The mean age for female patients was significantly older than male patients. The patients in the thrombolytic treatment group had mortality rate of 6.25% which is lower than that of the conservative treatment group at 12% (p>0.05). Conclusion: Although in our study, small number of acute myocardial infarct patients caused the statistical insignificance, rapid revascularization by thrombolytic therapy within 6 hours of onset of symptoms improved mortality rate and early ambulation. And we had good results on AMI with thrombolytic agent in ChungJu including near rural area as primary emergency hospital. Therefore a prospective research with greater number of subjects is needed to develop better treatments for AMI.

외부 프리스트레스 도입에 의한 노후된 콘크리트 거더교의 보강성능평가

박승범,홍석주,이봉춘,장석호,권혁준 충남대학교 산업기술연구소 2000 산업기술연구논문집 Vol.15 No.1

One of the promising methods to enhance the flexural strength of a externally prestressed girder is to place the tendons with large eccentricities. The analysis and design of composite girders prestressed by external tendons involve difficulties related mainly to the position of anchorages and the construction sequences. This study was conducted on the concrete bridges reinforced by the continuous girders and the external prestressing. The test results in this study showed that the external prestressing of a composite girder increased the range of the elastic behavior, reduced deflections, increased ultimate strength, and added to the redundancy by providing the multiple stress paths.

사각튜브의 동적 압괴 특성 연구

安大植,朴鳳賢,李鎭赫,韓庚基 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.-

Sixty six dynamic tests on thin-walled square aluminum tubes having cross-sections with t/b=0.333 and various speeds were crushed axially on a rail type equipment. Approximate theoretical predictions were modified for the axial progressive crushing of square box columns using N. Johns`s kinematically admissible method of analysis. This theoretical study predicts two deformation modes. New diagonal symmetric deformation mode were predicted theoretically and confirmed in the experimental tests. These diagonal symmetric mode cause an inclination of a column. The effective crushing distance is considered in the approximate theoretical analysis together with the influence of material strain rate sensitivity, which is important for steel but which is not important for aluminum. The simple equations presented herein for the design of axially crushed square box columns give reasonable agreement with the corresponding experimental results.

Fe-Ni-Co 저열팽창성 합금의 고온 변형 특성 및 열간가공에 따른 열팽창 거동 연구

이기안,박종혁,조봉현,남궁정,김문철 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.9

The high temperature deformation behavior and the effect of hot compression on the thermal expansion behavior of Fe-29Ni-17Co low thermal expansion Kovar alloy were investigated in the compressive temperature range of 900~1300℃ at the strain rate range of 25~0.01 sec.^(-1). The temperature (T) and strain rate (ε˙) dependence of the flow stress (σ_(0.7)) could be well described by hyperbolic sine law as ε˙= A [sinh(0.0084 σ)^(5.2018)] exp(-330.41/RT). Surface hot cracking and significant voids around grain boundary could be found at low temperature below 1000℃ and low strain rate (0.01 sec.^(-1)). Thermal expansion coefficient α_(30~400) generally increased with increasing compressive temperature. Moreover, α_(30~400) remarkably increased as strain rate decreased at high temperature above 1100℃. However the thermal expansion coefficient α_(30~400) of low compressive temperatures (900℃ and 1000℃) anomalously increased especially at high strain rates. Experimental results indicated that not only α phase appearance but also grain size had definite influence on the thermal expansion behavior with hot deformation. The correlation between microstructure and thermal expansion behavior of Kovar alloy were also discussed.

저열팽창성 Fe-29Ni-17Co 코바 합금의 고온균열 발생과 고온연성에 미치는 S 및 Mn의 영향

이기안,박종혁,조봉현,남궁정,김문철 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.12

The effect of S & Mn on the hot ductility of Fe-29Ni-17Co Kovar alloy and the mechanism of high temperature cracking occurrence were investigated. It has been found that the brittle intergranular fracture at high temperature cracking is closely associated with the sulfide along grain boundary. Experimental results showed, especially when the S content was high and the Mn content was free, that small cavities could be nucleated easily on FeS particles along grain boundary and propagated fast at high temperature. The hot ductility of Kovar alloy was drastically increased with the addition of Mn and it was also increased with decreasing S content. SEM and FE-SEM analyses showed that the Mn addition in this alloy could cause ductile intergranular fracture appearance below 1150℃ by the precipitation of MnS. It was proposed from the results that the addition of Mn and optimum S content (below 30 ppm) in Kovar alloy was necessary in order to reduce the hot cracking susceptibility.

소화성 궤양에서 삼제 병합 요법의 저용량에 의한 Helicobacter pylori 제균률과 궤양 치유효과

김예리,박봉안,이재동,이종혁,김인숙,박형석,진춘조,김상윤,박의우 건국대학교 의과학연구소 2000 건국의과학학술지 Vol.10 No.-

Helicobacter pylori is the major cause of histologic chronic gastritis and is strongly associated with peptic ulcer disease, gastric cancer and lymphoma. Several recommendations for the management of the Helicobacter pylori infection have been developed. However, there has been no clear therapeutic regimen for the optimal treatment of Helicobacter pylori infection. This study was desinged to evaluate the eradication rate and the ulcer healing rate of the triple regimen with low-dose clarithromycin(0.5g/day) in peptic ulcer patients. Forty three patients with gastric ulcer(n=15) and duodenal ulcer(n=28) were enrolled. The patients were treated either with omeprazole 20mg b.i.d. amoxicillin 0.5g b.i.d. and clarithromycin 250mg b.i.d. (low-dose regimen group, n=29) or with omeprazole 20mg b.i.d., amoxicillin 1.0g b.i.d. and clarithromycin 0.5g b.i.d.(high-dose regimen group, n= 14) for 2 weeks. After 4 weeks, the patients were evaluated for the eradication of Helicobacter pylori and the healing of ulcer. And gastritis scores according to the Sydney system were evaluated before and after 4 weeks from the end of the triple regimen. There was no significant difference in the eradication rate and the ulcer healing rate between the low-dose regimen group, group and the high-does regimen group. In the low-does regimen group, the mean initial scores of chronic inflammation and activity were decreased after the eradication of Helicobacter pylori. In conclusion, the low-dose triple regimen is as effective as the high-dose triple regimen on the eradication of Helicobacter pylori and the ulcer healing rate in peptic ulcer disease.

사람 뇌척수액중 Transthyretin의 항산화작용

양성렬,최기오,박종근,류문희,홍석노,김수한,안봉환,이제혁,이민화 대한신경외과학회 1994 Journal of Korean neurosurgical society Vol.23 No.4

Protective effects of human cerebrospinal fluid antioxidants against enzyme inactivation caused by metal-catalyzed oxidation systems were investigated. When purified glutamine synthetase(GS) was incubated with human cerebrospinal fluid(CSF), the enzyme was progressively inactivated. Catalase and EDTA could inhibit the enzyme inactivation by 50-80%. Small-molecular(Mr< -10,000) fraction of CSF inactivated the exogenous GS, but large-molecular(Mr> -10,000) fraction did not. The GS inactivation by the small-molecular fraction was also markedly inhibited by catalase and EDTA. These results suggested that metal-catalyzed oxidation is involved in the GS inactivation by the small-molecular fraction of CSF. Dithiothreitol(DTT) was shown to inhibit almost completely the oxidative inactivation of GS by CSF. However, DTT inhibited only partially the oxidative inactivation of GS caused by small-molecular fraction of CSF. When large-molecular fraction of CSF was separated by anion-exchange HPLC chromatogrpahy, there was a peak of antioxidant activity inhibiting the small-molecular fraction-induced GS inactivation in the presence of DTT. The antioxidant activity was neutralized by monoclonal antibodies to transthyretin. Purified transthyretin was found to efficiently inhibit ascorbate/Cu^(2+)-induced GS inactivation in the presence of DTT. Uric acid and glucose did not show any protective effect on the GS inactivation in the same condition. The above results suggest that metal-catalyzed oxidation occurs normally in human CSF, and that transthyretin may play an important role as a CSF antioxidant in protecting proteins from metal-catalyzed oxidation.

Si Bulk Micromachining을 위한 Wafer Rolling Etching 및 그 특성

김건년,이보나,박효덕,신상모,공경준,장동근,김병철,권혁채,이봉희 경북대학교 센서기술연구소 1998 센서技術學術大會論文集 Vol.9 No.1

A wafer rolling etching system for the silicon bulk micromachining has been designed and fabricated. The silicon diaphragms were anisotropically etched in a 24.5 weight percent KOH solution. Compared to the conventional KOH etching systems, pyramidal hillocks, and wave-shaped structures on the etched surfaces were greatly reduced by using this system. After etching for time of 438 minutes, the average etched depth and the etch-rate were measured to be 537μm and 1.22μm/min, respectively. The average etching uniformity of etching depth was 0.87% in 5-inch wafer. Our results showed that the wafer rolling method enhanced etch uniformity and etch rate.