• 한국약용작물학회지
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• 제13권6호
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• pp.217-225
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• 2005

강원도 산지의 뽕나무의 잎, 줄기, 뿌리를 건조하여 100% EtOH와 물로 추출하여 얻은 추출물 및 EtOH추출물로부터 용매별 분획물들을 NIH/3T3에 대한 세포독성, comet assay를 이용한 DNA damage손상으로부터 유전 독성, in vitro micronucleus assay를 이용한 유전독성, Ames test를 이용한 돌연변이 유발을 조사하여 다음과 같은 결과를 얻었다. 1) 각 시료들의 NIH/3T3에 대한 세포독성은 0.5mg/ml 농도에서 약 80%의 생육활성을 나타냈다. 2)뽕나무 잎의 1차 추출물들은 comet assay에서 양성 대조구 대비 약 40% 정도의 유전독성을 보였다. 뽕잎의 EtOH 추출물에서 분획한 분획물 시료중 수용성 분획은 거의 독성이 나타나지 않았으나, hexan의 0.25mg/ml 농도의 분획물이 약 50%정도를 보였으며 다른 시료들은 이 보다 약한 독성을 보였다. 또한 뽕나무 줄기의 분획물 시료들 중에서 0.5mg/ml 농도의 chloroform 분획물이 양성 대조구 대비 가장 강한 50%의 유전독성을 보인것 외에 다른 시료들은 그보다 약한 독성을 보였다. 3) In vitro micronucleus assay를 이용한 유전독성은 재료의 1차 추출물은 거의 유전독성이 나타나지 않았고 EtOH 추출물의 재분획물인 시료중에서 0.5mg/ml의 농도의 hexan 및 chloroform 분획물은 MN의 발생 빈도가 음성대조구에 비하여 약 2배의 증가로 나타났다 또 뽕나무 줄기의 분획물 시료들에서 0.5mg/ml의 hekan, chloroform 및 EtOAc 분획물에서 MN이 관찰 되었으나 그중 chloroform 분획물 시료에서 더 많은 MN 발생을 보였다. 4) Ames test를 이용한 돌연변이 실험결과 뽕나무 잎 1차 추출물들은 0.25mg/ml의 농도에서 TA98에 대하여 거의 돌연변이 현상이 없었고, EtOH 추출물로부터 재 분획한 BuOH 및 chloroform분 획물에서는 강한 돌연변이 현상이, 또 5mg/ml의 hekan 분획물에서는 더욱 강한 돌연변이 현상이 관찰되었다. TA100 strain에 대하여는 각 재료의 1차 추출물이나 분획들의 낮은 농도 (1.25mg/ml)에서는 돌연변이 현상이 매우 약하거나 거의 없었고, 0.25mg/ml의 1차 추출물들에서는 매우 약한 돌연변이가 나타났으나 이들의 EtOAc 분획물은 다소 강한 돌연변이 유발성이 관찰 되었다. 그러나 수용성 분획물은 두 균주에 대하여 전혀 돌연변이 유발성을 보이지 않았다. 5) 뽕나무 줄기로부터 조제한 시료중 수용성 분획물과 EtOAc분획물은 IA98에서 전혀 돌연변이 유발성이 없었으나 0.25mg/ml 농도외 물 추출물, EtOH 춘출물, hexan 및 chloroffrm분획물들이 약 40%증가한 복귀변이 콜로니가 관찰되었고, 이보다 농도를 증가시킨 물 추출물 및 BuOH 분획물에서도 같은 수준의 복귀변이 콜로니가 관찰 된 결과로부터 돌연변이 유발성이 있음이 확인되었다 TA100에 대하여 뽕나무 줄기의 수용성 분획물은 전혀 돌연변이가 나타나지 않았고, 0.25mg/ml의 물 추출물, EtOH추출물, hexan 및 BuOH분획물들이 약 10%증가한 약한 돌연변이가 관찰되었다. 그러나 농도를 5 mg/ml로 한 EtOAc 분획물은 26의 돌연변이 유발성을 보였다. 이상의 결과로 부터 뽕나무를 이용한 식용 제품생산을 고려할 때 추출물들의 제조와 선택을 가름하는 자료로서의 활용이 기대되며 앞으로 in vivo test 등 더욱 연구할 필요가 있을 것으로 사료된다.

• Bulletin of the Korean Chemical Society
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• 제26권4호
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• pp.529-536
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• 2005

Measurement of toxicologically relevant polychlorinated biphenyl (PCB) congeners such as non-ortho(IUPAC#) 77, 81, 126, 169 and mono-ortho 105, 114, 118, 123, 156, 157, 189 and di-ortho 170, 180 and polybrominated diphenyl ethers (PBDEs) such as 47, 66, 85, 99, 100, 138, 153, 154 in environmental samples become almost mandatory in several countries now. However, most of the available methods involve expensive instrumentations such as HRGC-HRMS or ECNI-LRMS, apart from expensive extraction and clean-up (with large volume of solvents) steps. A method has been devised combining the analytical separation power of PYE [2-(1-pyrenyl)ethyldimethysilylated silica] column HPLC and high-resolution gas chromatographic techniques including micro-electron capture detection (ECD) and two dimensional gas chromatograpy-ECD techniques to determine these eco-toxic substances at parts-per-trillion (ppt) levels. This combination resolves co-elution of congeners that occur in disproportionate ratios (e.g. CB-110 and -77) and allows accurate congener-specific determination of target compounds. This method is cost effective as it requires only hexane, that in small quantities (10 mL) and GC-ECD. The elution and analysis time are optimized to less man hours. This method is effectively utilized in the analysis of co-planar PCBs and PBDEs from archived solvent extracts of samples previously analyzed for pesticides and PCBs. Structure based separation of contaminant classes improves GCECD determination at ppt levels.

• Nutritional Sciences
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• 제9권3호
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• pp.159-166
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• 2006

This study was performed to investigate antioxidative and anti-aging action of extracts from Sancho (Zanthoxylum schinifolium) leaves. Two extracts were obtained by 80% methanol extraction followed by subsequent fractionation with methylene chloride (MC) and n-butanol (B) and fed at one or three levels to rats on normal level (5%) of fat (control) and high fat(20%) in diets. Male Sprague-Dawley rats weighing about 100 g were divided into ten groups such as control diet group(C), control diet+0.50%B group (CB), control diet+0.50%MC group (CMC), high-fat diet group (HF), high-fat diet+0.25%B group (HBL), high-fat diet+0.50%B group (HBM), high-fat diet+0.75%B group (HBH), high-fat diet+0.25%MC group (HMCL), high-fat diet+0.50%MC group (HMCM) and high-fat diet+ 0.75%MC group (HMCH) and fed each diet for four weeks. The effects of the extracts on antioxidant enzyme activities and indices of lipid peroxidation and aging were seen only in high fat diet groups. Hepatic superoxide dismutase and aryleaterase activities were not changed by Sancho extracts. But glutathione peroxidase, catalase and paraxonase activities were significantly restored by both MC and B at the level of 0.75% lipid peroxide which was increased by high fat diet was significantly reduced by B and MC at the level of 0.25% and over. Lipofuscin fluorescence and cabonyl value were increased by high fat diet were reduced by B and MC at the level of 0.5% and over. It is concluded that the Sancho extracts can be utilized as functional ingredients of health foods for reducing oxidative stress.

• 한국미생물·생명공학회지
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• 제43권1호
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• pp.16-21
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• 2015

2세대 바이오매스 볏짚을 이용하여 전자선 조사 후 NMMO 처리 공정을 수행하고 이를 분석하였다. 볏짚은 전자선 500 kGy 조사 후 NMMO 처리를 한 경우 72시간의 효소당화를 거쳐 글루코스 60.8%와 자일로스 9.7% 포함 약 83.8% 정도의 당수율을 보였다. 이 전처리 공정은 유해한 화학물질을 사용하지 않아서 친환경적이며 전자선 조사와 NMMO 처리의 시너지 효과가 있음을 알 수 있었다. 그러나 전자선 조사량이 너무 높다는 단점이 있으며 추후에는 낮은 전자선 조사량과 여러 가지 단일공정을 통합한 새로운 복합전처리 방법 연구의 필요성이 있다. 따라서 이 단점을 보완한다면 전자선 조사라는 친환경적 방법과 더불어 NMMO 용액의 재활용성을 이유로 바이오에탄올 생산 등의 산업현장에의 적용 가능성이 높다는 것을 알 수 있었다.

• Progress in Superconductivity
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• 제10권1호
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• pp.60-67
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• 2008

We present domestic efforts for superconducting fault current limiter (SFCL) application in the Korea Electric Power Corporation (KEPCO) grid and pending points at issue. KEPCO's decision to upgrade the 154 kV/22.9 kV main transformer from 60 MVA to 100 MVA cast a problem of high fault current in the 22.9 kV distribution lines. The grid planners supported adopting an SFCL to control the fault current. This environment friendly to SFCL application must be highly dependent upon the successful development of SFCL having specifications that domestic utility required. The required conditions are (1) small size of not greater than twice of 22.9 kV gas insulated switch-gear (GIS), (2) sustainability of current limitation without the line breaking by circuit breakers (CB) for maximum 1.5 seconds. Also, optionally, recommended is (3) the reclosing capability. Conventional resistive SFCLs do not meet (1) $\sim$ (3) all together. A hybrid SFCL is an excellent solution to meet the conditions. The hybrid SFCL consists of HTS SFCL components for fault detection and line commutation, a fast switch (FS) to break the primary path, and a limiter. This characteristic structure not only enables excellent current limiting performances and the reclosing capability, but also allows drastic reduction of HTS volume and small size of the cryostat, resulting in economic feasibility and compactness of the equipment. External current limiter also enables long term limitation since it is far less sensitive to heat generation than HTS. Semi-active operation is another advantage of the hybrid structure. We will discuss more pending points at issues such as maintenance-free long term operation, small size to accommodate the in-house substation, passive and active control, back-up plans, diagnosis, and so on.

• 한국식물병리학회지
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• 제12권1호
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• pp.1-10
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• 1996

Xanthomonas campestris pv. vesicatoria의 감염으로 토마토 잎조직에 $\beta$-1, 3-Glucanases와 chitinases가 합성, 축적되었다. 그러나 접종되지 않은 건전한 잎에서는 위의 두 가지 가수분해 효소는 매우 낮은 수준으로 유지되었고, 이 두 가지 효소는 친화적 상호작용에서보다는 불친화적 상호작용에서 더욱 높은 수준으로 존재하였다. 이것은 $\beta$-1, 3-glucanases와 chitinases가 X. c. pv. vesicatoria의 생육에 대한 방어기작으로서 중요한 역할을 한다는 것을 시사해 주고 있다. Native PAGE 젤 상에서 $\beta$-1, 3-glucanases를 분리한 결과, 병징 발현이나 저항성 발현에 중요한 역할을 하는 것으로 생각되는 산성 isoform Ga 1과 염기성 isoform Gb 1의 isoform bands만 확인되었다. Isoelectric focusing을 이용하였을 때, 적어도 pI 6.4와 pI 8.6을 지닌 두 개의 $\beta$-1, 3-glucanases의 isoform을 확인할 수 있었고, 특히 불친화적 상호작용에서 더욱 뚜렷하게 유도되었다. 이것은 병 진전과정에서 X. c. pv. vesicatoria에 대해 저항성 발현에 관여한다는 것을 나타내고 있다. 산성 chitinase isoform인 Ca 1의 활성은 병원균의 감염이 진전되는 동안 감소하였다. 또한 다섯 개의 염기성 chitinase isoform이 감염된 토마토 잎 조직에서 발견되었는데, 특히 토마토의 방어기작에 관여하여 병원화적 균주 Bv5-4a에 감염된 잎에서만 유도, 축적되었다. Isoelectric focusing(IEF)을 이용한 후 적어도 2개의 산성과 4개의 염기성 chitinase isoform이 감염된 토마토 잎 추출액에서 확인되었다. Native PAGE 젤에서 isoform Cb 1에 해당되는 pI 9.5를 지닌 chitinase isoform은 오직 불친화적 상호작용에서만 확인되었다. 이온이 제거된 Triton X-100을 처리하여 renaturation 시킨 후에 SDS-PAGE 젤 상태에서 23 kDa과 26 kDa을 지닌 2개의 chitinase isoform을 확인하였다.

• 동력기계공학회지
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• 제22권1호
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• pp.41-47
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• 2018

This paper analyzes the output characteristics of a self excited induction generator with isolated mode according to change of its speeds and loads for building a hybrid electric propulsion system in special purpose ships by using power take off. The induction generators are being considered as an alternative choice to the well-developed generators because of their lower unit cost, inherent ruggedness, operational and maintenance simplicity. However, the generator working by stand alone has a few problems that the reactive power is required to establish the air gap magnetic flux, and the induced voltage and magnetizing current fluctuate when the load is varied. In spite of its advantages, basic design data of the capacitor bank and behaviors of the output characteristics of the generator are not sufficient for the system. Based on the operating condition(speed range of main engine) of the target boat, a reduced experimental equipment system was constructed to analyze the output characteristics of the SEIG. And a suitable capacitor bank of a stand-alone generator and its output characteristics under various loads was investigated in detail through these experiments. According to the experimental result, it was confirmed that the capacitor bank should be $70{\mu}F{\sim}100{\mu}F$, and the proper SEIG induced voltage should be DC 80 V ~ 250 V in order to storage electrical energy into a battery.

• 한국환경과학회지
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• 제20권11호
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• pp.1499-1507
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• 2011

Practical disposal of transformer insulation oil laden with PCBs (polychlorinated biphenyls) by a chemical treatment has been studied in field work. The transformer insulation oil containing PCBs was treated by the required amounts of PEG (polyethylene glycol) and KOH, along with different reaction conditions such as temperatures and times. The reaction of PEG with PCBs under basic condition produces arylpolyglycols, the products of nucleophilic aromatic substitution. Removal efficiencies of PCBs in insulation oil before and after chemical treatment were examined. The removal efficiency of PCBs was very low at lower temperatures of 25 and $50^{\circ}C$. Under the reaction condition of PEG 600/KOH/$100^{\circ}C$/2hr, removal efficiency of PCBs was approximately 70%, showing completely removal of PCBs containing 7~9 chlorines on biphenyl frame which appear later than PCB IUPAC Number 183 (2,2',3,4,4',5',6-heptaCB) in retention time of GC/ECD. However, when increasing the reaction temperature and time to $150^{\circ}C$ and 4 hours, removal efficiency of PCBs reached 99.99% without any formation of PCDDS/PCDFs during the process. Such reaction conditions were verified by several official analytical institutions. In studying the reaction of PEG with PCBs, it confirmed that the process of chemical treatment led to less chlorinated PCBs through a stepwise process with the successive elimination of chlorines.

• 식품보건융합연구
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• 제6권5호
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• pp.11-17
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• 2020

This study tried to analyze sensual properties by classifying the thermal water extract of the main material used in Ssanghwa tea. Through this study, we wanted to develop popular Ssanghwa tea and further carry out basic research for the development of various menus using it. The ingredients for the Ssanghwa tea were washed under running water, then dehydrated and put in a pot as 2L of purified water. Ssangwha tea were heated at 100℃ for 10 minutes, then lowered the temperature to 75℃ and boiled down to 200 ml for 110 minutes. This study evaluated sensory characteristics of four types of commercial products and the five types manufactured by the description analysis. Quantitative analysis of the commercial Ssanghwa tea showed significant differences between samples in seven of the total 13 sensory characteristics except OG(Smell of grass), OC(Oriental medicine smell), TG(Umami), RT(Thick), RC(Rough) and RS(Tub-Tub) (p<0.05). In particular, differences between samples were evident in CT(Transmittance), CB(Brownness), TW(Sweet taste) and TB(Bitter) (p<0.001), which appeared to be the main differentiated features of appearance, aroma and taste for commercial Ssanghwa tea. This study tried to analyze sensual properties by classifying the thermal water extract of the main material used in Ssanghwa tea. Through, we wanted to develop popular Ssanghwa tea and further carry out basic research for the development of various menus using it.

• 한국식품저장유통학회지
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• 제30권6호
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• pp.969-982
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• 2023

This study evaluated the impact of blanching pak choi stems and leaves in various solutions (distilled water, 2% NaCl, and 2% citric acid) at 100℃ on their quality characteristics. The highest stem heating loss was observed in the sodium chloride solution (S-NB) at 15.10% (p<0.001), and the highest leaf heating loss was in L-NB at 11.44% (p<0.001). No significant variation was found in the moisture content of both stems and leaves. Relative to the control, the L value (lightness) of the stem decreased while the b value (yellowness) increased (p<0.05). In the leaves, the a value (redness/greenness) and b value increased in L-CB, whereas they decreased in other groups (p<0.05). S-NB exhibited the highest true retention (TR) of total polyphenol content (TPC) in stems (p<0.01) and the highest TR of total flavonoid content (TFC) as well (p<0.001). For leaves, the highest TR of TPC and TFC was in L-WB (p<0.001). In terms of antioxidant activity, S-NB in stems and L-WB in leaves showed the highest scavenging activity measured by DPPH and ABTS⁺ assays (p<0.001). Microorganisms were absent in all pretreatment groups but present in the control. The results suggest that blanching pak choi stems in 2% NaCl solution and leaves in water optimally preserves biologically active compounds and nutrients.