• Korean Journal of Pharmacognosy
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• v.51 no.4
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• pp.325-331
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• 2020

Through Caenorhabditis elegans model system, the antioxidant activity of methanol extract of the guzeunggupo-processed Platycodon grandiflorum A. De Candolle (Campanulaceae) roots was calculated. Between the methanol extracts of guzeunggupo-processed and non-processed P. grandiflorum roots, the processed P. grandiflorum root showed higher DPPH radical scavenging effect than the non-processed one. The ethyl acetate soluble fraction of the methanol extract of the guzeunggupo-processed P. grandiflorum showed the best DPPH radical scavenging activity. The ethyl acetate fraction of the processed sample was measured for the activities of superoxide dismutase (SOD), catalase, and oxidative stress tolerance by using C. elegans along with reactive oxygen species level. In addition, to confirm the regulation of the stress response gene is responsible for the increased stress tolerance of C. elegans treated by the ethyl acetate fraction of the processed sample, SOD-3 expression was measured using a transgenic strain (CF1553). Consequently, the ethyl acetate fraction of the processed sample, increased SOD and catalase activities, and decreased ROS accumulation in a dose-dependent manner. Furthermore, the ethyl acetate fraction of the processed sample-treated CF1553 worm showed higher SOD-3::GFP intensity than the control worm.

• Korean Journal of Pharmacognosy
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• v.31 no.2
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• pp.190-195
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• 2000

In the previous reports, we selected 80% MeOH extract of 7 herbs including Scutellariae Radix(SR), Paeoniae Radix Rubra(PRR), Moutan Cortex(MC), Angelicae Gigantis Radix(AGR), Crataegi Fructus(CF), Bambusae Caulis in Taeniam(BCT) and Cinnamomi Ramulus(CR), which exhibited the inhibitory effect on HMG-CoA reductase and DPPH free radical scavenging effect in vitro, and antihyperlipidemic effects on antihyperlipidemic rats induced by Triton WR 1339 in vivo. Among them, SR, MC, AGR and BCT showed significant suppression of elevated serum LDL-cholesterol level, and AGR and CF showed significant liver weight increase on high cholesterol diet induced hyperlipidemic mice. And, SR, PRR, AGR, BCT and CR significantly suppressed the elevated serum total cholesterol and triglyceride levels on corn oil induced hyperlipidemic rats. Then, in order to research new antihyperlipidemic agents from the oriental medicinal herbs, we chose SR, AGR, CR and BCT which have the antihyperlipidemic effect in vitro and in vivo, and those herbs were systematically fractionated with organic solvent. EtOAc fraction of SR, hexane fraction of BCT, AGR and chloroform fraction of CR exhibited remarkably inhibitory effect on HMG-CoA reductase activity.

• Korean Journal of Pharmacognosy
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• v.53 no.4
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• pp.207-212
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• 2022

Through the Caenorhabditis elegans model system, the antioxidant activity of methanol extract of Ixeis dentata was investigated. The ethyl acetate soluble fraction of the I. dentata methanol extract showed the best DPPH radical scavenging activity. The ethyl acetate fraction was measured for the activity of superoxide dismutase (SOD), catalase, and oxidative stress tolerance by using C. elegans along with reactive oxygen species (ROS) level. In addition, to confirm that the regulation of the stress response gene is responsible for the increased stress tolerance of C. elegans treated by the ethyl acetate fraction, SOD-3 expression was measured using a transgenic strain (CF1553). As a result, the ethyl acetate fraction increased SOD and catalase activity, and decreased ROS accumulation in a dose-dependent manner. In addition, the ethyl acetate fraction-treated CF1553 worm showed higher SOD-3::GFP intensity than the control worm.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.97-97
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• 2010

많은 플라즈마 공정 중에 건식 식각은 복잡하고 표면반응이 잘 알려지지 않은 등의 이유로 가장 어려운 분야 중의 하나이다. 이러한 이유로 식각 장치 디자인뿐만 아니라 플라즈마를 이용한 건식 식각의 공정 조건은 수많은 시행착오를 통해 시도되어 왔다. 이런 문제들을 극복하기 위해 많은 연구자들에 의해서 다양한 방법과 tool을 이용해 모델링이 시도되고 있다. 본 연구에서는 $CF_4$ 가스를 이용한 유도결합 플라즈마에 의해 Si와 $SiO_2$를 식각하는 것을 상용 프로그램인 전산모사 유체역학 시뮬레이터인 CFD-ACE+를 이용하여 모델링했다. 150 mm 직경의 웨이퍼에 대한 모델은 식각 속도 실험결과와 비교 하였다. Ar의 경우 20 mTorr에서 13.56 MHz, 500 W인가 시 2.0 eV의 전자온도와 $7.3{\times}10^{11}\;cm^{-3}$의 전자밀도가 계산결과와 상당히 일치하게 측정되었고, $CF_4$를 이용한 $SiO_2$ 식각에서도 식각 속도가 평균 190 nm/min로 일치했고 식각 균일도는 3% 였다. 450 mm 웨이퍼 공정용 장치의 모델 계산 결과에서는 안테나와 기판의 거리, 챔버의 단면적, 기판 지지대와 배기구와의 높이 등 기하학적인 구조와 각 안테나 턴의 위치 및 전류비가 플라즈마 균일도에 많은 영향을 주었으며, 안쪽부터 4 turn이 있는 경우 2번째, 4번째 turn에만 1:4의 전류비를 인가했을 때, 수십%의 전자밀도의 불균일도를 4.7%까지 낮출 수 있었다. 또한, Si 식각에서는 식각 속도의 분포가 F radical의 분포와 같은 경향을 보임을 확인했고, $SiO_2$ 식각에서는 전자 밀도의 분포와 일치함을 확인함으로써 균일한 식각을 위해서 두 물질의 식각 공정에서는 다른 접근의 시도가 필요함을 확인했다. 플라즈마의 준중성 조건을 이용해서 Poisson 방정식을 풀지 않고 sheath를 해석적 모델로 처리하는 방법과, Poisson 식으로 정전기장을 푸는 방법을 통해서 입사 이온의 에너지 분포를 비교하였다. 에너지 범위는 80~120 eV로 같지만, 실험에서는 IED가 낮은 에너지 쪽이 더 높게 측정됐고, 계산 결과에서는 높은 에너지 쪽이 높았다.

• Food Science and Preservation
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• v.14 no.2
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• pp.177-182
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• 2007

This study was performed to investigate the antioxidant effect of 80% (v/v) ethanol extract from Chaenomelis Fructus (CF). Total flavonoids and total polyphenols in the extract were also measured spectrophotometrically. The extraction yield was 9.23g/100g CF. The extract was further fractionated by partition with n-hexane, chloroform, ethylacetate, butanol, and water. The water fraction showed the highest extraction yield of all fractions. The n-hexane method and compared with the properties of the commerical antioxidant BHT. The activities of the n-hexane fraction were the highest of all fractions. In addition, there was strong positive correlation between antioxidant activities and levels of antioxidative compounds, such as flavonoid and polyphenols, in CF fractions, suggesting that these antioxidative compounds may contribute to the antioxidative effect of CF.

• Korean Journal of Pharmacognosy
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• v.49 no.4
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• pp.322-327
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• 2018

Methanol extract of Salvia miltiorrhiza Bunge (Labiatae) root was investigated to research the anti-oxidative activity, by using a Caenorhabditis elegans model system. The methanol extract of this plant showed significant DPPH radical scavenging and superoxide quenching activities. Ethyl acetate soluble fraction of the methanol extract that showed the most potent DPPH radical scavenging and superoxide quenching activities. The ethyl acetate fraction was tested on its activities of superoxide dismutase (SOD), catalase, and oxidative stress tolerance in C. elegans. Furthermore, in order to see if regulation of stress-response genes is responsible for the increased stress tolerance of the ethyl acetate fraction treated C. elegans, we checked SOD-3 expression using a transgenic strain. Consequently, the ethyl acetate fraction of S. miltiorrhiza root increased the catalase and SOD activities in a dose-dependent manner in C. elegans. Besides, the ethyl acetate fraction-treated CF1553 worms showed higher SOD-3::GFP intensity than the non-treated ones.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.27 no.2
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• pp.75-79
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• 2017

Honeycomb-shaped Ag-grid transparent conductive electrodes (TCEs) were fabricated using two different processes, high density plasma etching and lift-off, and the optical and electrical properties were compared according to the fabrication method. For the fabrication of the Ag-grid TCEs by plasma etching, etch characteristics of the Ag thin film in $10CF_4/5Ar$ inductively coupled plasma (ICP) discharges were studied. The Ag etch rate increased as the power increased at relatively low ICP source power or rf chuck power conditions, and then decreased at higher powers due to either decrease in $Ar^+$ ion energy or $Ar^+$ ion-assisted removal of the reactive F radicals. The Ag-grid TCEs fabricated by the $10CF_4/5Ar$ ICP etching process showed better grid pattern transfer efficiency without any distortion or breakage in the grid pattern and higher optical transmittance values of average 83.3 % (pixel size $30{\mu}m/line$ width $5{\mu}m$) and 71 % (pixel size $26{\mu}m/line$ width $8{\mu}m$) in the visible range of spectrum, respectively. On the other hand, the Ag-grid TCEs fabricated by the lift-off process showed lower sheet resistance values of $2.163{\Omega}/{\square}$ (pixel size $26{\mu}m/line$ width $18{\mu}m$) and $4.932{\Omega}/{\square}$ (pixel size $30{\mu}m/line$ width $5{\mu}m$), respectively.

• Applied Science and Convergence Technology
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• v.23 no.4
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• pp.169-178
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• 2014

Fluid model based numerical analysis is done to simulate a low damage etch back system for 20 nm scale semiconductor fabrication. Etch back should be done conformally with very high material selectivity. One possible mechanism is three steps: reactive radical generation, adsorption and thermal desorption. In this study, plasma generation and transport steps are analyzed by a commercial plasma modeling software package, CFD-ACE+. Ar + $CF_4$ ICP was used as a model and the effect of reactive gas inlet position was investigated in 2D and 3D. At 200~300 mTorr of gas pressure, separated gas inlet scheme is analyzed to work well and generated higher density of F and $F_2$ radicals in the lower chamber region while suppressing ions reach to the wafer by a double layer conducting barrier.

• Bulletin of the Korean Chemical Society
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• v.31 no.12
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• pp.3718-3722
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• 2010

Theoretical investigations are carried out on the title reaction by means of ab-initio and DFT methods. The optimized geometries, frequencies and minimum energy path are obtained at UB3LYP/6-311G(d,p) level. Single point energy calculations are performed at MP2 and MP4 levels of theory. Energetics are further refined by calculating the energy of the species with a modified Gaussian-2 method, G2M(CC,MP2). The rate constant of the reaction is calculated using Canonical Transition State Theory (CTST) utilizing the ab-initio data obtained during the present study and is found to be $5.47{\times}10^{-12}\;cm^3\;molecule^{-1}s^{-1}$ at 298 K and 1 atm.

• Korean Journal of Pharmacognosy
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• v.47 no.2
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• pp.179-185
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• 2016

Ginger (Zingiber officnale Roscoe, Zingiberaceae), which is a well-known food seasoning, has been used as a traditional medicine for the treatment of gastrointestinal disorder, vomiting and cough in Korea, China and Japan. Ethanol extract from the dried ginger (DG) was successively partitioned as methylene chloride, ethyl acetate, n-butanol and $H_2O$ soluble fractions. Among those fractions the ethyl acetate soluble fraction (EDG) showed the most potent DPPH radical scavenging and superoxide quenching activities. To know the effect of antioxidant activities of EDG, we tested the activities of superoxide dismutase (SOD) and catalase together with oxidative stress tolerance and intracellular ROS level in Caenorhabditis elegans. To investigate whether EDG-mediated increased stress tolerance was due to regulation of stress-response gene, we quantified SOD-3 expression using transgenic strain including CF1553. Consequently, EDG elevated SOD and catalase activities of C. elegans, reduced intracellular ROS accumulation in a dose-dependent manner. Moreover, EDG-treated CF1553 worms exhibited significantly higher SOD-3::GFP intensity.