불화음용수 섭취에 따른 백서골의 미세특성 및 결정구조 비교분석

사공억,김지영,송재상,권용훈,송근배 대한구강보건학회 2003 大韓口腔保健學會誌 Vol.27 No.1

The wide spread use of various vehicles for systemic or topical delivery of fluoride is undoubtedly responsible in large part for the remarkable decline in the prevalence of dental caries that is currently being experienced in many countries of the western world. But the effects of fluoride on bone health has been not completely confirmed still now. The aims of this study were to understand the micro-chemical and mechanical changes and the effects of the fluoride on rat femur after administration of various concentrations of fluoride. The three point bending test, surface micorhardness test, fluoride analysis, FT-Raman spectrophotometer and scanning electron microscopy were performed. The obtained results ware as follows; 1. Bone strength was increased significantly in the 5 and 25ppm group compared to control and 1ppm group. On the other hand, there was a significant decrease of stress at fracture in 75ppm group than 25ppm group(p<0.005). 2. Surface microhardness of the femur were also increase in the 1,5 and 25ppm groups than control and decreased at 75ppm group, but there were no significant differences in all the group(p<0.05). 3. With increasing the concentration of administrated fluoride, contents of fluoride in the ashed femur were increased. It was the highest in the 75ppm group than other groups(p<0.05). 4. The change of hydroxyapatite to fluorrapatite structure was not differentiated by FT-Raman analysis.

복합 적층판의 T-Joint에 대한 접착 강도 평가

김재훈,사정우 충남대학교 공업교육연구소 2000 論文集 Vol.23 No.1

The test specimen configuration of T-joint was proposed to evaluate the bond strength and damage mechanism between a skin and co-cured stringer or frame. When the static loading, such as monotonic loading, loading/unloading, the skin was bent along the edge of the frame. A test fixture which could change moment arm was designed for simply support condition. AE signal and optical crack propagation were monitored by AE measurement instrument and CCD camera in real-time during the test. The failure initiated and progressed on the noodle area. Results indicate that the failure initiation load was decreased by increasing distances between skin/flange termination point and support rod. Also it was shown that a significant amount of acoustic emission was suddenly generated by new damage.

스트레인 게이지를 이용한 두께 최적화 하단고정체에 대한 구조시험 평가

김재훈,사정우,김덕희 忠南大學校 産業技術硏究所 1997 산업기술연구논문집 Vol.12 No.2

The atomic fuel rods between the top and bottom end piece of reactor need to be extended for the high combustion rate of future-type fuel to increase the irradiation in the axial direction. For allowing the axial extension of the fuel rods, the space between the top and bottom end piece should be expanded. Thus the thickness optimization of the flow plate is necessary. This study was carried out the mechanical strength test by using strain gages as a function of flow plate thickness, the existence of skirt and loading condition for the Korean fuel assembly(KOFA). The experimental apparatus was designed for load conditions, uniformly distributed load and displacement. Test method using whiffle tree of uniformly distributed load has been comparatively conservative. The test results were compared with those of FEM analysis and the test method on bottom end piece was established.

음성 인식 헬스케어 시스템

신진우,조우승,조성빈,김재훈,정지은,사예지,백경동,박동규 순천향대학교 부설 산업기술연구소 2021 순천향 산업기술연구소논문집 Vol.27 No.2

As modern people's interest in health grows, wearable healthcare-related technologies that can collect biometric information and receive health-related services regardless of time and place are developing. This paper proposes the healthcare system based on voice recognition function. Unlike conventional wearable healthcare systems, the proposed system provides real-time telemedicine and diagnosis and the direct connection with doctors is possible through it. And almost all functions of the application in it are operated with voice commands to lower user access barriers. Because it deals with personal information including medical information, encryption algorithms have been applied between all data movements. Finally, the healthcare system proposed in this paper is expected to increase convenience in health care and reduce the medical gap.

Session L : Protein Structure and Function : IDENTIFICATION AND PROPERTIES OF TWO HEAT - STABLE THIOREDOXINS FROM Schizosaccharomyces pombe

Jae Hoon Sa,Su Hyun Choi,Dong Seok Kwak,Kyung Hoon Kim,Chang Jin Lim 생화학분자생물학회(구 한국생화학분자생물학회) 1993 추계학술대회집 Vol.- No.-

Variations in Enzyme Activities during Arabidopsis Leaf Growth

Jae-Hoon Sa,Chang-Jin Lim 강원대학교 기초과학연구소 1997 기초과학연구 Vol.8 No.-

Activities of various enzymes were measured and compared in the growing leaves of Arabidopsis tlnliann. Phenylalanine ammonia-lyase activity is maximal in the leaves of 2-week-grown Arabidopsis. Tyrosine ammonia-lyase activity is maximal in the leaves of 3-week-grown and 4-week-grown Arabidopsis. Activity of thioltransferase, an enzyme involved in the reduction of various disulfide compounds, is higher in younger leaves than in older ones. A similar pattern was obtained in the activity of thiordoxin, a small protein known as a cofactor of ribonucleotide reductase and a regulator of photosynthesis. Activity of glutathione reductase is also higher in the younger leaves. Malate dehydrogenase activity remains relatively constant during the growth of Arabidopsis leaves. The results offer preliminary informations for further approach to elucidate mechanism on growth-dependent variations of these enzymes.

Activities of Sulfhydryl-Related and Phenylpropanoid-Synthesizing Enzymes during Leaf Development of Arabidopsis thaliana

Sa, Jae-Hoon,Park, Eun-Hee,Lim, Chang-Jin Korean Society for Biochemistry and Molecular Biol 1998 Journal of biochemistry and molecular biology Vol.31 No.6

Activities of glutathione- and thioredoxin-related enzymes and phenylpropanoid-synthesizing enzymes were measured and compared in the developing leaves of Arabidopsis thaliana. Phenylalanine ammonia-lyase activity is maximal in the leaves of 2-wk-grown Arabidopsis. Tyrosine ammonia-lyase activity is maximal in the leaves of 3-wk-grown and 4-wk-grown Arabidopsis. Activity of thioitransferase, an enzyme involved in the reduction of various disulfide compounds, is higher in younger leaves than in older ones. A similar pattern was obtained in the activity of thioredoxin, a small protein known as a cofactor of ribonucleotide reductase and a regulator of photosynthesis. Activity of glutathione reductase is also higher in the younger leaves. Malate debydrogenase activity remains relatively constant during the development of Arabidopsis leaves. The results offer preliminary information for further approach to elucidate the mechanism of growth-dependent variations of these enzymes.

Characterization of Thioltransferase from Kale

Sa, Jae-Hoon,Yong, Mi-Young,Song, Byung-Lim,Lim, Chang-Jin Korean Society for Biochemistry and Molecular Biol 1998 Journal of biochemistry and molecular biology Vol.31 No.1

Thioltransferase, also known as glutaredoxin, is an enzyme that catalyzes the reduction of a variety of disulfides, including protein disulfides, in the presence of reduced glutathione. Thioltransferase was purified from kale through ammonium sulfate fractionation, DE-52 ion-exchange chromatography, Sephadex G-75 gel filtration, and Q-Sepharose ion-exchange chromatography. Its molecular size was estimated to be about 31,000 daltons on SDS-PAGE. The purified enzyme has an optimum pH of about 8.0 with 2-hydroxyethyl disulfide as a substrate. The enzyme also utilizes L-sulfocysteine, L-cystine, bovine serum albumin, and insulin as substrates in the presence of GSH. The enzyme has $K_m$ values of 0.24-0.67 mM for these substrates. The enzyme was partly inactivated after heating at $80^{\circ}C$ or higher temperature for 30 min. The enzyme was stimulated by various thiol compounds such as reduced glutathione, dithiothreitol, L-cysteine, and $\beta$-mercaptoethanol. This is a second example of a plant thioltransferase which was purified and characterized.

Characterization of Thioltransferase from Kale

Jae-Hoon Sa,Mi-Young Yang,Byung-Lim Song,Chang-Jin Lem 강원대학교 기초과학연구소 1997 기초과학연구 Vol.8 No.-

Thioltransferase, also known as glutaredoxin, is an enzyme that catalyzes the reduction of a variety of disulfides, including protein disulfides, in the presence of reduced glutathione. Thioltransferase was purified from kale through ammonium sulfate fractionation, DE-52 ion-exchange chromatography, Sephadex G-75 gel filtration, and Q-Sepharose ion-exchange chromatography. Its molecular size was estimated to be about 13,000 daltons on SDS- PAGE. The purified enzyme has an optimum pH of about 8.0 with 2-hydroxyethyl disulfide as a substrate. The enzyme also utilizes L-sulfocysteine, L-cystine, bovine serum albumin, and insulin as substrates in the presence of GSH. The enzyme has Km values of 0.24-0.67 mM against these substrates. The enzyme was partly inactivated after heating at 80℃ or higher temperature. The enzyme was greatly activated by various thiol compounds such as reduced glutathione, dithiothreitol, L-cysteine and β-mercaptoethanol. This is a second example of plant thioltransferase, which was purified and characteried

Effect of Cyclic AMP on the Two Promoters of Escherichia coli Thioredoxin Gene

Sa, Jae-Hoon,Fuchs, James A.,Lim, Chang-Jin Korean Society for Biochemistry and Molecular Biol 1997 Journal of biochemistry and molecular biology Vol.30 No.5

Thioredoxin is a multi-functional protein which is ubiquitous in microorganisms, animals and plants. Previously, expression of the E. coli thioredoxin gene was found to be negatively regulated by cAMP. In the present study, the effect of cAMP on two separate promoters of the E. coli thioredoxin gene was investigated. Cyclic AMP had a repressible effect on P1 and P1P2 promoter activity of the constructs. This effect was also observed in the cya strain. The P2 promoter construct gave very high -galactosidase activity, and its expression was not affected by exogenous cAMP. It was assumed that a cis-acting negative element, probably the cAMP-CRP binding site, might have been deleted in the P1 promoter construct. Repression of the thioredoxin gene expression by cAMP appeared to be independent of ppGpp.