• The Korean Journal of Physiology and Pharmacology
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• 제24권5호
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• pp.373-384
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• 2020

Paeonol, quercetin, β-sitosterol, and gallic acid extracted from Moutan Cortex had been reported to possess anti-oxidative, anti-inflammatory, and anti-tumor activities. This work aimed to illustrate the potential anti-oxidative mechanism of monomers in human liver hepatocellular carcinoma (HepG2) cells-induced by hydrogen peroxide (H₂O₂) and to evaluate whether the hepatoprotective effect of monomers was independence or synergy in mice stimulated by carbon tetrachloride (CCl₄). Monomers protected against oxidative stress in HepG2 cells in a dose-response manner by inhibiting the generation of reactive oxygen species, increasing total antioxidant capacity, catalase and superoxide dismutase (SOD) activities, and activating the antioxidative pathway of nuclear factor E2-related factor 2/Kelch-like ECH-associated protein 1 (Nrf2/Keap1) signaling pathway. We found that the in vitro antioxidant capacities of paeonol and quercetin were better than those of β-sitosterol and gallic acid. Furthermore, paeonol apparently diminished the levels of alanine transaminase and aspartate aminotransferase, augmented the contents of glutathione and SOD, promoted the expressions of Nrf2 and heme oxygenase-1 proteins in mice stimulated by CCl₄. In HepG2 cells, paeonol, quercetin, β-sitosterol, and gallic acid play a defensive role against H₂O₂-induced oxidative stress through activating Nrf2/Keap1 pathway, indicating that these monomers have anti-oxidative properties. Totally, paeonol and quercetin exerted anti-oxidative and hepatoprotective effects, which is independent rather than synergy.

• 한국전기전자재료학회논문지
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• 제22권10호
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• pp.821-825
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• 2009

Recently, transparent ZnO-based TFTs have attracted much attention for flexible displays because they can be fabricated on plastic substrates at low temperature. We report the fabrication and characteristics of ZnO TFTs having different channel thicknesses deposited at low temperature. The ZnO films were deposited as active channel layer on $Si_3N_4/Ti/SiO_2/p-Si$ substrates by RF magnetron sputtering at $100^{\circ}C$ without additional annealing. Also, the ZnO thin films deposited at oxygen partial pressures of 40%. ZnO TFTs using a bottom-gate configuration were investigated. The $Si_3N_4$ film was deposited as gate insulator by PE-CVD at $150^{\circ}C$. All Processes were processed below $150^{\circ}C$ which is optimal temperature for flexible display and were used dry etching method. The fabricated devices have different threshold slop, field effect mobility and subthreshold slop according to channel thickness. This characteristics are related with ZnO crystal properties analyzed with XRD and SPM. Electrical characteristics of 60 nm ZnO TFT (W/L = $20\;{\mu}m/20\;{\mu}m$) exhibited a field-effect mobility of $0.26\;cm^2/Vs$, a threshold voltage of 8.3 V, a subthreshold slop of 2.2 V/decade, and a $I_{ON/OFF}$ ratio of $7.5\times10^2$.

• 한국전기전자재료학회논문지
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• 제27권12호
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• pp.866-870
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• 2014

In solid oxide fuel cell system, yttria-stabilized zirconia is generally adopted as the electrolyte, which has high strength and superior oxygen ion conductivity, and the air electrode and the fuel electrode are attached to this. Recently, new structure of 'layered planar SOFC module' was suggested to solve the reliability problem due to the high temperature stability of a sealing agent and a binding material. In this study to materialize the air electrode in a layered planar SOFC module, the LSM ink was coated to form homogeneous electrode in the channel after the ink preparation. As the porosity control agent, PMMA or active carbon powder was adopted with use of a commercial dispersant in ethanol. The optimal amounts of both the porosity control agents and the dispersant were determined. Four (4) vol% of the dispersant for the LSM-PMMA case and 15 vol% for LSM-carbon powder showed the lowest viscosities respectively to indicate the best dispersed states of the slurries. With PMMA and carbon powder, sintered LSM ink shows the relatively homogeneous distributions of pores and with increases of the agents, the porosities increased in both cases. From this, it can be thought that the amount of the PMMA or carbon powder could be used to control the porosity of the LSM ink.

• 대한방사성의약품학회지
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• 제1권2호
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• pp.137-144
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• 2015

Hypoxia is an important adverse prognostic factor for tumor progression and is a major cause of failure of radiation therapy. In case of short-term hypoxia, the metabolism can recover to normal, but if hypoxia persists, it causes irreversible cell damage and finally leads to death. So a hypoxia marker would be very useful in oncology. In particular, 2-nitroimidazole can be reduced to form a reactive chemical species, which can bind irreversibly to cell components in the absence of sufficient oxygen, thus, the development of radiolabeled nitroimidazole derivatives for the imaging of hypoxia remains an active field of research to improve cancer therapy result. 2-nitroimidazole based hypoxia marker, [$^{18}F$]FMISO holds promise for the evaluation of tumor hypoxia by Positron emission tomography (PET), at both global and local levels. In the present study, [$^{18}F$]FMISO was synthesized using an automatic synthesis module with high radiochemical purity (>99%) in 60 min. Immunohistochemical analysis using pimonidazole confirmed the presence of hypoxia in xenografted CT-26 tumor tissue. A biodistribution study in CT-26 xenografted mice showed that the increased tumor-to-muscle ratio and tumor-to-blood ratios from 10 to 120 min post-injection. In the PET study, [$^{18}F$]FMISO also showed increased tumor-to-muscle ratios from 10 to 120 min post-injection. In conclusion, this study demonstrates the feasibility and utility of [$^{18}F$]FMISO for imaging hypoxiain mouse colon cancer model using small animal PET.

• 공업화학
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• 제3권3호
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• pp.471-481
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• 1992

본 연구는 아민을 리간드로 갖는 산소가교 팔라듐 착화합물의 반응성에 관한 것이다. 이 경우에 합성한 산소 가교 팔라듐 착화합물은 산소원으로서 초과산화이온(${O_2}^-$)을 사용했다. 합성한 산소가교 팔라듐 착화합줄의 형태를 검토하기 위하여 벤젠 용매중에서 물, 메탄올, 아세트산과의 반응을 행하였다. 그 결과 산소가교 팔라듐 착화합물은 이들과 반응하여 과산화수소($H_2O_2$)를 발생하면서 각각 히드록시, 메톡시, 아세톡시가교 팔라듐 착화합물로 변환되었다. 또한 산소가교 팔라듐 착화합물은 치환 페놀류인 살리실알데히드, 8-히드록시퀴놀린 및 활성메틸렌 화합물인 아세틸아세톤, 디메틸말론산과 반응하여 과산화수소와 단핵 팔라듐 착화합물을 생성했다. 더욱 산소가교 팔라듐 착화합물은 아세톤과도 반응하여 아세토닐가교 팔라듐 착화합물과 과산화수소로 변환되었다. 이것은 착화합물 중의 배위산소가 과산화이온(${O_2}^{2-}$)이며, 강한 염기로서 작용하고 있음을 시사한다.

• 생태와환경
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• 제42권2호
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• pp.153-160
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• 2009

비점오염원으로부터 오염된 소하천에서 영양염류를 제거하기 위하여 식물플랑크톤 배양 장치를 설치하고 운영하였다. 식물플랑크톤 배양조에서 식물플랑크톤 정치배양 결과, 식물플랑크톤의 연속배양을 위한 배양조의 체류 시간을 3일로 결정하였으며 TP는 70%, TN은 44%가 제거됨을 확인하였다. 연속배양 결과 45일 동안 배양조에 유입된 TP의 53.9%, TN의 53.1%가 식물플랑크톤에 의한 흡수와 슬러지로 제거되었다. 식물플랑크톤이 성장하면서 배양조의 pH와 용존산소농도는 각각 평균 10.8, 16mg $L^{-1}$이었다. 결국 비점오염원에 오염된 하천수의 영양 염류는 식물플랑크톤의 사체와 화학반응으로 생성된 침전물로 제거되었다. 비교적 설치가 간단하고 경제성이 높은 식물플랑크톤 배양법의 높은 현장적용 가능성을 확인하였다.

• 한국식품과학회지
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• 제23권3호
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• pp.251-255
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• 1991

들기름의 산화안정성 향상을 위해 primary antioxidant로 이용한 몇 가지 상업용 레시틴에 토코페롤, 구연산, ascorbyl palmitate 등의 항산화제 및 상승제를 첨가하여 들기름의 산화방지 효과 및 상승효과를 AOM 시험과 OVEN 시험에 의하여 비교 연구하였다. AOM시간이 2시간인 들기름에 5%의 상업용 레시틴을 첨가했을 때 우제유사(迂製油社) I 제품만이 8시간인 것을 제외하고 AOM 시간이 16시간인 정제 대두유의 유도시간 보다 길었다. 레시틴의 종류 및 농도에 따른 AOM 시험 조건에서의 산화안정성과 $60,\;37^{\circ}C$ OVEN 시험에서의 산화안정성은 유사한 실험결과를 나타냈다. 토코페롤은 일반 유지의 경우와는 다르게 ${\gamma}-rich-tocopherol$이${\dalta}-rich-tocopherol$과 mixed tocopherol를 첨가한 경우 보다 항산화 효과가 우수하였다. 또한 들기름에 레시틴의 첨가량을 증가할 수록 유도시간이 증가되었으며 레시틴에 대한 토코페롤, 구연산, ascorbyl palmitate의 혼합물은 상승효과가 인정되었다.

• 한국식품과학회지
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• 제28권1호
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• pp.184-189
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• 1996

냉이(Capsella bursa-pastoris)로부터 산소독성에 영향을 미치는 superoxide anion radical에 대하여 소거작용을 하는 물질을 분리하고 이 물질의 이화학적 성질을 검토하였다. 냉이를 에탄올로 추출한 후 용매분획과 각종 column chromatographies (Amberlite XAD-2, Sephadex LH-20, Bio gel P-2, ODS)를 통해 정제하였고, 최종적으로 FPLC (Fast protein liquid chromatography)를 사용하여 활성의 단일물질을 얻었다. 냉이 에탄올추출물 100 g으로부터 0.25 g의 정제물질을 얻었으며, superoxide anion radical을 50% 소거하는 농도$(IC_{50})$는 $0.58\;{\mu}g$이었다. 이 물질에 대해 각종 이화학적 성질을 검토한 결과 phenol성 화합물의 배당체로 추정하였다.

• 대한의용생체공학회:의공학회지
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• 제27권4호
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• pp.143-153
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• 2006

The purpose of this work was to assess and quantify the beneficial effects of gas exchange, while testingto the various frequencies of the sinusoidal wave that was excited by the PZT actuator, for patients suffering from acute respiratory distress syndrome (ARDS) or chronic respiratory problems. Also, this paper considered a simulator to design a hollow type artificial lung, and a mathematical model was used to predict a behavior of blood. This simulation was carried out according to the Montecarno's simulation method, anda fourth order Runge-Kutta method was used to solve the equation. The experimental design and procedure are then applied to the construction of a new device to assess the effectiveness of the membrane vibrations. As a result, the vibration method is very effective in the increase of gas transport. The gas exchange efficiency for the vibrating intravascular lung assist device can be increased by emphasizing the following design features: consistent and reproducible fiber geometry, and most importantly, an active means of enhancing convective mixing of water around the hollow fiber membranes. The experimental results showed the effective performance of the vibrating intravascular lung assist device. Also, we concluded that important design parameters were blood flow rates, fiber outer diameter and oxygen pressure drop. Based on the present results, it was believed that the optimal level of blood flow rates was 200$cm^3$/min.

• 한국표면공학회지
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• 제47권5호
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• pp.239-243
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• 2014

The electrical and optical properties of amorphous In-Tin-Zinc-Oxide(ITZO) deposited at room temperature using rf-magnetron sputtering were investigated. The amorphous ITZO thin films were obtained at the composition of In:Sn:Zn = 6:2:2, 4:3:3, and 2:4:4, but the ITZO (8:1:1) showed a crystalline phase of bixbyite structure of In2O3. The resistivity of ITZO could be controlled by oxygen pressure in the sputtering ambient. The resistivity of post-annealed ITZO thin films exhibited the dependence on the amount of Indium. Optical energy band gap and transmittance increased as the amount of indium in ITZO increased. For the device application with ITZO, the bottom-gated thin-film transistor using ITZO as a active channel layer was fabricated. It showed a threshold voltage of 1.42V and an on/off ratio of $5.63{\times}10^7$ operated with saturation field-effect mobility of $14.2cm^2/V{\cdot}s$.