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흰민들레의 동맥경화 유발인자인 저밀도 지질단백질 산화에 미치는 영향
전철민,양기숙,Jeon, Cheol-Min,Yang, Ki-Sook 한국생약학회 1996 생약학회지 Vol.27 No.3
The methanol extract of Taraxacum coreanum Nakai (Compositae) was examined on the in vitro oxidation of human low density lipoprotein (LDL). It is well known that LDL oxidation induced artherosclerosis, if we can protect LDL oxidation process, excess plasma lipoprotein accumulation into the arterial lesion prone areas can be blocked. The methanol extract was treated with oxidized LDL which was incubated with $16\;{\mu}M$ $Cu^{2+}$ for metal catalyzed oxidation and TBA value, mobility on agarose gel and formation of conjugated diene and change of vitamin E were determined for the evaluation. The extract showed antioxidative effect at concentration $200\;{\mu}g/ml$ on LDL oxidation.
An Analysis of Temperature Change and TI MI using Tissue Mimicking Phantom in Ultrasonic Examination
전철민(Cheol-Min Jeon),한재복(Jae Bok Han),곽종길(Jong Gil Kwak),송종남(Jong Nam Song) 한국방사선학회 2022 한국방사선학회 논문지 Vol.16 No.6
현재 진단 초음파 및 건강검진 목적의 초음파 검사는 널리 이용되고 있고 건강보험 적용으로 더욱 증가 추세를 보이고 있다. 하지만 초음파검사의 위해성은 현재까지 명확히 밝혀진 바가 없어 초음파 검사 시 인체 조직의 온도가 상승하는 열효과를 알아보고자 본 연구에서는 인체 모의 매질 팬텀을 이용해 주파수, 모드별에 따른 표면과 심부 온도 변화를 시간별로 측정하였고 TI, MI 값도 비교하였다. 인체와 유사한 음향 특성 있는 카파 카라기난 분말과 고형화를 위해 염화칼륨을 소량 첨가하여 모의 팬텀 제작하였고 표면 온도계와 탐침용 온도계를 사용하여 표면과 심부 온도 변화를 측정하였다. 그 결과 저주파수를 사용하는 Convex Probe가 고주파를 사용하는 Linear Probe보다 높은 온도 상승을 보여 유의미한 차이를 보였고 표면에서 온도 상승이 가장 높았으며 1 cm의 낮은 깊이는 일시적 온도상승은 나타내지만 유의미한 온도변화는 없었다. 5 cm ∼ 15 cm의 심부온도 변화는 없었으며 검사 시간동안 TI, MI값은 변화가 없었다. 이는 15분 실험동안 표면온도만 상승하였고 심부에는 온도변화가 없었기 때문에 인체에 유해할 만큼의 온도 변화를 나타내지 않을 것으로 사료되며 통상적인 진단초음파의 15분의 검사시간은 임상에서의 사용에는 무리가 없을 것으로 생각되지만 특정 부위의 장시간 검사는 온도 상승을 일으킬 수 있으므로 지양해야 될 것으로 사료된다. Currently, ultrasound examination for diagnostic ultrasound and health examination purposes is widely used, and it is showing an increasing trend due to the application of health insurance. However, the risk of ultrasound has not been clearly identified so far, and in this study, surface and deep temperature changes according to frequency and mode were measured by using a tissue mimicking phantom and TI and MI values were compared. A simulated phantom was manufactured by adding a small amount of kappa-caraginan powder with acoustic characteristics similar to that of the human body and potassium chloride for solidification, and the change of surface and depth temperature was measured using a surface thermometer and a probe thermometer. As a result, the convex probe using low frequency showed a higher temperature increase than the linear probe using high frequency, so there was a significant difference, and the temperature increase was the highest on the surface, and the depth of 1cm showed a temporary temperature increase, but there was no significant temperature change. There was no change in the deep temperature of 5 cm to 15 cm, and the TI and MI values did not change during the test time. Since only the surface temperature rose during the 15-minute test and there was no temperature change in the core, so it is not expected to show a temperature change that is harmful to the human body. However, it is thought that prolonged examination of one area may cause temperature rise, so it should be avoided.
중성자분말회절법을 이용한 금운모 결정에 대한 리트벨트 구조분석
이철규 ( Lee Cheol Gyu ),송윤구 ( Song Yun Gu ),전철민 ( Jeon Cheol Min ),김신애 ( Kim Sin Ae ),성기훈 ( Seong Gi Hun ) 한국광물학회 2003 광물과 암석 (J.Miner.Soc.Korea) Vol.16 No.3
The Rietveld structure refinement for the natural trioctahedral mica, phlogopite-l M (Parker Mine, Quebec, Canada) has been done by high resolution neutron powder diffraction at 25℃ and -263℃. The structural formula of phlogopite determined by electron probe microanalysis is K₂(Mg_(4.46)Fe_(0.83)Al_(0.34)Ti_(0.22)) (Si_(5.51)Al_(2.49))O_(20)(OH_(3.59)F_(0.41)). Cell parameters are α=5.30-5.31 A, b=9.18-9.20 A, c=l0.18-10.21 A, β=l00.06-100.08˚. Refinements converged to R values in the range of R_(p)=2.35 -2.51%, R_(wp)=3.01 -3.18%, respectively. In this study, the OH bond length is calculated to 0.93 Å at room temperature and 1.03 Å at -263℃, and the angles between OH vector and (001) plane are obtained 9.4˚∼9.6˚. The decrease in the length of OH with the increase in temperature should be due to the hydrogen bonding in the structure of phogopite.
산도변화와 침지시간이 광중합 복합레진의 잔류단량체 유출에 미치는 영향
전철민,유현미,권혁춘 大韓齒科保存學會 2004 Restorative Dentistry & Endodontics Vol.29 No.3
Objectives : The purpose of this study was to determine whether pH and time has any influence on the degradation behavior of composite restoration by analyzing the leached monomers of dental composites qualitatively and quantitatively after storage in acetate buffer solution as a function of time using high performance liquid chromatography (HPLC) / mass spectrometer. Materials and Methods : Three commercial composite restorative resin materials (Z-250, Heliomolar and Aeliteflo) with different matrix structure and filler composition were studied. Thirty specimens (7 ㎜ diameter × 2 ㎜ thick) of each material were prepared. The cured materials were stored in acetate buffer solution at different pH (4, 7) for 1, 7 and 45days. As a reference, samples of unpolymerized composite materials of each product were treated with methanol (10 mg/ml). Identification of the various compounds was achieved by comparison of their mass spectra with those of reference compound, with literature data, and by their fragmentation patterns. Data were analysed statistically using ANOVA and Duncan's test. Results : 1. Amounts of leached TEGDMA in Aeliteflo were significantly larger than those of UDMA in Z-250 and Heliomolar at experimental conditions of different storage time and pH variation (p<0.001). 2. As to comparison of the amounts of leached monomers per sorage time, amounts of leached TEGDMA in Aeliteflo and UDMA in 2-250 and Heliomolar were increased in the pH 4 solution more significantly than in the pH 7 solution after 1day, 7days and 45days. respectively (p<0.001). 3. In total amounts of all the leached monomers with storage times, the overall amounts of pH 4 extracts were larger than those of pH 7 extracts for all resin groups, but there was no significant difference (p >0.05).