• 생약학회지
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• 제43권4호
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• pp.297-301
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• 2012

In the course of screening for antioxidant compounds by measuring the radical scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH), a total extract of the twigs of Taxillus delavayi (Loranthaceae) was found to show potent radical scavenging activity. Subsequent activity-guided fractionation of the methanolic extract led to the isolation of two phenolic compounds, catechin (1) and galloyl catechin (2), as active principles. Their structures were elucidated by spectroscopic studies. These two compounds showed the significant antioxidative effects on DPPH, and riboflavin- and xanthin-originated superoxide quenching activities. And these two compounds also showed strong nitric oxide radical scavenging effects. In riboflavin- and xanthin-originated superoxide quenching activities and nitric oxide radical scavenging effect, compound 2 showed better antioxidant activities than vitamin C.

• 상하수도학회지
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• 제25권2호
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• pp.223-230
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• 2011

An electrolytic oxidation process was applied to remove odorous compounds from non-point odor sources including wastewater pipelines and manholes. In this study, a distance between the anode and the cathode of the electrolytic process was varied as a system operating parameters, and its effects on odor removal efficiencies and reaction characteristics were investigated. Odor precursors such as sediment organic matters and reduced sulfur/nitrogen compounds were effectively oxidized in the electrolytic process, and a change in oxidation-reduction potential (ORP) indicated that an stringent anaerobic condition shifted to a mild anoxic condition rapidly. At an electrode distance of 1 cm and an applied voltage of 30 V, a system current was maintained at 1 A, and the current density was 23.1 $mA/cm^{2}$. Under the condition, the removal efficiency of hydrogen sulfide in gas phase was found to be 100%, and 93% of ammonium ion was removed from the liquid phase during the 120 minute operating period. Moreover, the sulfate ion (${SO_4}^{2-}$) concentration increased about three times from its initial value due to the active oxidation. As the specific power consumption (i.e., the energy input normalized by the effective volume) increased, the oxidation progressed rapidly, however, the oxidation rate was varied depending on target compounds. Consequently, a threshold power consumption for each odorous compound needs to be experimentally determined for an effective application of the electrolytic oxidation.

• 생명과학회지
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• 제19권1호
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• pp.138-146
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• 2009

마늘은 역학조사에 의하면 각종 질환의 예방과 치료에 효능이 있는 것으로 알려져 있다. 마늘의 주요 성분인 알리신 성분은 매우 불안정하여 쉽게 분해되어 새로운 형태의 유황 화합물로 만들어져 이들 성분들이 상승적으로 작용하여 중요한 생리황성을 갖는 것으로 알려져 있다. 시판되고 있는 여러 종류의 마늘제품 중에서 숙성마늘제품이 다른 제품에 비하여 생리활성이 높은 것으로 보고되었다. 숙성마늘제품은 마늘을 일정한 조건으로 숙성시킬 때 수용성 성분인 S-allylcysteine, S-allylmercaptan, steroid saponins, te-trahydro-${\beta}$-caboline derivatives 및 fructeosyl-arginine 등이 많이 증가하여 그 효능이 상승적으로 높아지는 것으로 알려져 있다. 따라서 시판 마늘가공품의 품질을 표준화하기 위하여 이들 수용성 성분을 biomarker로서 규격기준을 정해야 할 것이다.

• Molecules and Cells
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• 제39권12호
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• pp.869-876
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• 2016

Cantharidin (CTD) is an active compound isolated from the traditional Chinese medicine blister beetle and displayed anticancer properties against various types of cancer cells. However, little is known about its effect on human chronic myeloid leukemia (CML) cells, including imatinib-resistant CML cells. The objective of this study was to investigate whether CTD could overcome imatinib resistance in imatinib-resistant CML cells and to explore the possible underlying mechanisms associated with the effect. Our results showed that CTD strongly inhibited the growth of both imatinib-sensitive and imatinib-resistant CML cells. CTD induced cell cycle arrest at mitotic phase and triggered DNA damage in CML cells. The ATM/ATR inhibitor CGK733 abrogated CTD-induced mitotic arrest but promoted the cytotoxic effects of CTD. In addition, we demonstrated that CTD downregulated the expression of the BCR-ABL protein and suppressed its downstream signal transduction. Real-time quantitative PCR revealed that CTD inhibited BCR-ABL at transcriptional level. Knockdown of BCR-ABL increased the cell-killing effects of CTD in K562 cells. These findings indicated that CTD overcomes imatinib resistance through depletion of BCR-ABL. Taken together, CTD is an important new candidate agent for CML therapy.

• Progress in Superconductivity
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• 제3권1호
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• pp.13-16
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• 2001

We have measured the reflectivity of superconducting infinite-layer compounds $Sr_{0.9}$ $Ln_{0.1}$ Cu $O_2$ (Ln=La, Gd, Sm) with $T_{c}$ : 39 K using a Fourier-transform infrared spectrometer. We have identified the optical phonon modes from their infrared reflectivity and conductivity spectra and have proposed possible displacement patterns. The La- and the Gd-doped compounds exhibited only four ($2A_{2u}$ $+2E_{u}$) out of the five ($2A_{2u}$ $3E_{u}$) infrared-active phonons predicted by a group theoretical analysis whereas the Sm-doped compound exhibited all five modes. For the La-doped sample, we investigated the temperature dependence of the optical response functions in a wide temperature range of 7 - 300 K. In FIR region, the reflectivity is apparently enhanced below ~120 $cm^{-1}$ as temperature decreases across $T_{c}$. The value of $2$\Delta$/k_{B}$ $T_{c}$ is about 4.5, which is consistent with maximum gap value of d-wave $high- T_{c}$ cuprates.> c/ cuprates.uprates.s.

• Journal of the Korean Wood Science and Technology
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• 제37권1호
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• pp.73-77
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• 2009

본 연구는 우리나라 전역에 분포하고 있는 물오리나무의 추출성분으로부터 유용한 항산화 물질을 탐색하기 위해 수행되었다. 물오리나무 수피를 70% acetone 수용액으로 추출하여 분획한 후 ethyl acetate 분획과 수용성 분획을 Sephadex LH-20으로 충진된 column으로 chromatography를 수행하여 혼합물을 정제하고 두 개의 diarylheptanoid 화합물을 얻었다. 단리된 화합물은 $^1H$, $^{13}C$-NMR 및 2D-NMR 분석을 통하여 1,7-bis-(3,4-dihydroxyphenyl)-heptane-3-one-5-O-${\beta}$-D-xylopyranoside (1, oregonin)와 1,7-bis-(3,4-dihydroxyphenyl)-heptane-5-O-${\beta}$-D-xylopyranoside (2)로 구조를 규명하였다. 두 개의 diarylheptanoid 화합물과 oregonin 가수분해물에 대한 항산화 활성(DPPH)을 측정한 결과 세 화합물 모두 높은 활성을 보였으며, 특히 oregonin 가수분해물의 항산화 활성은 $IC_{50}$이 2.6으로 높은 활성을 보였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.208-209
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• 2011

In this work, we developed self-assembled monolayers (SAMs) of alkanethiols on gold that can release amine groups, when an electrical potential was applied to the gold. The strategy was based on the introduction of the electroactive carbamate group, which underwent the two-electron oxidation with simultaneous release of the amine molecules, to alkanethiols. The synthesis of the designed thiol compounds was achieved by coupling isocyanate-containing compound with hydroquinone. The electroactive thiols were mixed with hydroxyl-containing alkanethiol [$HS(CH_2)_{11}OH$] to form mixed monolayers, and cyclic votammetry was used for the characterization of the release. The mixed SAMs showed a first oxidation peak at +540 mV (versus Ag/AgCl reference electrode), demonstrating irreversible conversion from carbamate to hydroqinone with simultaneous release of the amine groups. The second and third cycles showed typical reversible redox reaction of hydroquinone and quione: the oxidation and reduction occurred at +290 mV and -110 mV, respectively. The measurement of ToF-SIMS further indicates that electrochemical-assisted chemical reaction successfully released amine groups. This new SAM-based electrochemistry would be applicable for direct release of biologically active molecules that contain amine groups.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.334-334
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• 2012

Transparent oxide semiconductors have recently attracted much attention as channel layer materials due to advantageous electrical and optical characteristics such as high mobility, high stability, and good transparency. In addition, transparent oxide semiconductor can be fabricated at low temperature with a low production cost and it permits highly uniform devices such as large area displays. A variety of thin film transistors (TFTs) have been studied including ZnO, InZnO, and InGaZnO as the channel layer. Recently, there are many studies for substitution of Ga in InGaZnO TFTs due to their problem, such as stability of devices. In this work, new quaternary compound materials, tantalum-indium-tin oxide (TaInSnO) thin films were fabricated by using co-sputtering and used for the active channel layer in thin film transistors (TFTs). We deposited TaInSnO films in a mixed gas (O2+Ar) atmosphere by co-sputtering from Ta and ITO targets, respectively. The electric characteristics of TaInSnO TFTs and thin films were investigated according to the RF power applied to the $Ta_2O_5$ target. The addition of Ta elements could suppress the formation of oxygen vacancies because of the stronger oxidation tendency of Ta relative to that of In or Sn. Therefore the free carrier density decreased with increasing RF power of $Ta_2O_5$ in TaInSnO thin film. The optimized characteristics of TaInSnO TFT showed an on/off current ratio of $1.4{\times}108$, a threshold voltage of 2.91 V, a field-effect mobility of 2.37 cm2/Vs, and a subthreshold swing of 0.48 V/dec.

• 한국환경농학회지
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• 제36권1호
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• pp.36-42
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• 2017

BACKGROUND: Yuza seed by-product has been produced in a large amount from the agricultural farms in the southern area of Korea. It has been mostly abandoned after commercial process for the production of juice, jam and tea. The study on the reuse of the yuza seed by-product has received much attention as a bio-resource material for the production of active compound in agriculture. METHODS AND RESULTS: Insecticidal rhamnolipid-producing Pseudomonas sp. EP-3 was grown in mineral salt media with the yuza seed by-product at 2, 20, 50 and 100 g/L. The growth of EP-3 was accompanied by a increase in insecticidal activity against green peach aphid. The highest insecticidal activity was observed when EP-3 was grown in the medium containing 50 g/L of the seed sample, producing approximately 996 mg/L of rhamnolipid at 96 h. Palmitic acid, stearic acid, oleic acid and linoleic acid were determined as the major fatty acids of the seed sample. The EP-3 cultures grown on the fatty acid mixture extracted from the seed sample showed a aphid mortality similar to that of cultures grown on the seed sample. The EP-3 cultures grown on 50 g/L of the seed sample showed aphid mortality more than 90% under greenhouse conditions. CONCLUSION: This study suggested that the yuza seed by-product may be used as a renewable material for microbial production of rhamnolipid against green peach aphid.

• Food Science and Biotechnology
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• 제18권2호
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• pp.336-342
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• 2009

To confirm the antimicobial mechanism of Torilis japonica, antimicrobial profile was observed on various spore conditions by combining 0.1% (3 mM) torilin with antimicrobial activity and 0.27% water fraction with germinants. A 75% ethanol extract of T. japonica fruit reduced Bacillus subtilis ATCC 6633 spore counts by 3 log cycles and reduced the vegetative cells to undetectable level (by about 6 log cycles) (both in terms of CFU/mL). Further fractionating the ethanol extract into n-hexane and water fractions revealed that the former reduced the spore count by 1 log cycle whereas the latter had no effect. The antimicrobial active compound was isolated and purified from the hexane layer, and identified as torilin ($C_{22}H_{32}O_5$). The water fraction of the ethanol layer did not show antimicrobial activity, whereas the antimicrobial effect of 0.1% (3 mM) torilin was significantly enhanced in the presence of the water fraction (0.27%). This result can be explained by synergistic effects of the water fraction containing considerable amounts of germinants such as L-alanine and K+ ions that triggered germination.