• 전기전자학회논문지
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• 제21권2호
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• pp.170-173
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• 2017

본 연구에서는 Al, Mo 및 Pt 금속 물질을 a-IGZO 박막트랜지스터의 게이트 전극으로 플라스틱 기판 위에 형성하여 제작하고, 게이트 물질에 따른 전기적 특성을 측정하였다. Al 게이트 전극에 비해 Pt 게이트 전극을 사용한 박막트랜지스터의 문턱전압은 -4.1V에서 -0.3 V까지 감소하였고, 전하이동도는 $15.8cm^2/V{\cdot}s$에서 $22.1cm^2/V{\cdot}s$ 로 향상되었다. 게이트 전극에 따른 박막트랜지스터의 문턱전압 이동은 전극의 일함수와 채널층의 페르미 에너지 차이로 인한 영향이라는 것을 확인 할 수 있었다. 또한, 채널 물질의 페르미 에너지를 고려하였을 경우에 Pt 게이트 전극이 박막트랜지스터의 전기적 특성 면에서 적합한 물질로 확인되었다. 추가적으로 Mo 게이트 전극을 사용한 박막트랜지스터에 대한 특성도 본 논문에서 다룬다.

• 농업과학연구
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• 제46권4호
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• pp.799-811
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• 2019

The aim of this study was to evaluate heavy metal contamination and pollution index of agricultural soils around industrial complexes in the Jeon-Buk Regions of Korea. Soil samples near industrial complexes in 2017 were collected at two depths (0 - 15 and 15 - 30 cm) within a 500- and 1000-meter radius before planting. Eight heavy metals (Arsenic (As), cadmium (Cd), chromium (Cr), Cupper (Cu), nickel (Ni), lead (Pb), mercury (Hg) and zinc (Zn)) and the pollution index (PI), geoaccumulation index (Igeo) and soil pollution index (SPI) were evaluated based on soil contamination warning standard (SCWS). Overall, the heavy metal concentrations were below the SCWS. The PI ranged from 0.1 to 0.9 and categorized into Group 1 which is not polluted with any heavy metals. The average Igeo values of all the soil samples ranged from - 2.56 to 3.22. The Igeo values of Cd and Hg may not represent well the pollution index because the heavy metal concentrations in the soil is lower compared to the SCWS. In fact, based on the heavy metal concentrations, the Igeo for monitored soils should be categorized into Group 1, uncontaminated to moderately contaminated. However, the Igeo of Cd and Hg are classified into heavily contaminated. These results suggest that for calculating the Igeo, the heavy metal concentration and background concentration should be used very carefully if the heavy metal concentration in the soil is lower than the background concentration. SPI for all the soil samples ranged from 0.00 to 0.11 which indicates no heavy metal pollution was observed.

• JSTS:Journal of Semiconductor Technology and Science
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• 제15권5호
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• pp.519-525
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• 2015

Positive bias stress-induced instability in amorphous indium-gallium-zinc-oxide (a-IGZO) bottom-gate thin-film transistors (TFTs) was investigated under high $V_{GS}$/low $V_{DS}$ and low $V_{GS}$/high $V_{DS}$ stress conditions through incorporating a forward/reverse $V_{GS}$ sweep and a low/high $V_{DS}$ read-out conditions. Our results showed that the electron trapping into the gate insulator dominantly occurs when high $V_{GS}$/low $V_{DS}$ stress is applied. On the other hand, when low $V_{GS}$/high $V_{DS}$ stress is applied, it was found that holes are uniformly trapped into the etch stopper and electrons are locally trapped into the gate insulator simultaneously. During a recovery after the high $V_{GS}$/low $V_{DS}$ stress, the trapped electrons were detrapped from the gate insulator. In the case of recovery after the low $V_{GS}$/high $V_{DS}$ stress, it was observed that the electrons in the gate insulator diffuse to a direction toward the source electrode and the holes were detrapped to out of the etch stopper. Also, we found that the potential profile in the a-IGZO bottom-gate TFT becomes complicatedly modulated during the positive $V_{GS}/V_{DS}$ stress and the recovery causing various threshold voltages and subthreshold swings under various read-out conditions, and this modulation needs to be fully considered in the design of oxide TFT-based active matrix organic light emitting diode display backplane.

• 한국환경보건학회지
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• 제9권2호
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• pp.11-17
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• 1983

The soil-transmitted helminthes, such as ascaris, whipworm, hookworm and trichostrongylus, have been considered as the most prevalent parasitic diseases in a matter of several decades ago in Korea. In facts, the attached eggs and/or larvae to the vegetables have been played a great role on the transmission to human because of raw eating the vegetables without the proper recipe. The aims of this study is to outline the attached helminthes egg in vegetables and to define whether the detection rates on them show a decreasing pattern or not in present. The subjected vegetables were collected from the three markets which are located at Goo-Pa Bal, Soo-Yoo Dong, Cheon-Ho Dong in suburban area, Seoul from April to May 1983. A total of 180 samples including such as 60 Korean cabbages, 60 young radishes and 60 Korean onions were examined. For the detection of helminthes eggs, the both methods of formalin-ether sedimentation and zinc-sulfate floatation were applied. The results were summarized as follows: 1) The detected eggs of ascaris, whipworm, hookworm, trichostrongylus and either filariform larvae or rhabditoidform larvae of hookworm, as well as unknown ones were found in vegetables subjected. 2) Out of 180 subjects, the overall detection rate showed 48 (26.7%). And in case of Korean onion, the rate revealed 22 heads (36.7%) among 60, 17 heads (28.3%) out of 60 Korean cabbages, 9 roots (15.0%) out of 60 young radishes respectively. 3) The ascaris eggs were detected 6 heads (10%) out of 60 Korean cabbages, while the filariform larvae of hookworm appeared in 7 heads (11.7%) among 60 Korean onions. 4) In the results of present study, the detection rates in vegetables were appeared to be the marked decreasing tendency as like 28.3%, 36.7%, 15% compared with 96%, 100%, 88% of previous investigators (Choi et al. 1967)each on Korean cabbage, Korean onion, young radish.

• Asian Pacific Journal of Cancer Prevention
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• 제16권15호
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• pp.6609-6613
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• 2015

Background: Matrix metalloproteinases (MMPs) are a family of zinc metalloproteinases capable of degrading components of connective tissues. MMP-10 is frequently expressed in human cancers. The aim of this study was to immunohistochemically evaluate its expression in oral squamous cell carcinoma (OSCC) and verrucous carcinoma (OVC). Materials and Methods: A retrospective analysis of 73 samples (31 OSCC, 22 OVC and 20 non-neoplastic epithelium) was performed. All samples were immunohistochemically stained with monoclonal MMP-10 antibody and expression levels and staining intensity were evaluated with respect to microscopic features. Data were analyzed by SPSS (V.21), Mann-Whitney and Kruskal Wallis tests. Results: MMP-10 was detected in all OSCC and OVC cases. The expression of MMP-10 in OSCC was intensive (score 3) and in OVC was low and moderate (score 1 and score 2) more frequently. Non- neoplastic epithelium did not show MMP-10 expression. Differences between groups was statistically significant (p<0.05). However, the expression of MMP-10 was not obviously different between various grades of OSCC. Conclusions: According to our study, MMP-10 protein can be important possible factor in the transformation of normal oral epithelium to OVC and OSCC, also the level of MMP-10 expression at invasion front of the lesions can be helpful in the differentiation of OVC and OSCC.

• 한국식품영양학회지
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• 제30권1호
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• pp.148-155
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• 2017

This study aimed to investigate the effect of acorn powder and starch on the blood parameters of mice fed a high-fat diet. The moisture, crude ash, crude protein, and crude fat contents of acorns were $37.99{\pm}0.37%$, $1.61{\pm}0.06%$, $4.36{\pm}0.18%$ and $3.22{\pm}0.15%$, respectively. Acorn powder and starch contains antioxidant minerals such as selenium and zinc. The iron content was significantly higher in acorn powder than in acorn starch (p<0.05). The total cholesterol concentration was $148.50{\pm}29.72mg/dL$ in the high-fat starch diet (HFS) group, while in the high-fat diet (HF) group it was $201.50{\pm}39.15mg/dL$ (p<0.05). Serum LDL-cholesterol concentrations were significantly lower in the HFS group ($50.50{\pm}10.79mg/dL$) than in the HF group ($62.00{\pm}20.85mg/dL$; p<0.05). The serum $IL-1{\beta}$ levels in mice were not significantly different between the groups. IL-10 levels were higher in the HFP group than other groups. There is a need for strong recognition that acorns are good ingredients worldwide. It is required to develop various products using acorn powder and starch powder. There is also a need for a strategy to globalize food using acorns.

• The Korean Journal of Physiology and Pharmacology
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• 제15권2호
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• pp.83-88
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• 2011

A large body of evidence has indicated that induction of endogenous antioxidative proteins seems to be a reasonable strategy for delaying the progression of cell injury. In our previous study, cilostazol was found to increase the expression of the antioxidant enzyme heme oxygenase-1 (HO-1) in synovial cells. Thus, the present study was undertaken to examine whether cilostazol is able to counteract tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$)-induced cell death in endothelial cells via the induction of HO-1 expression. We exposed human umbilical vein endothelial cells (HUVECs) to TNF-${\alpha}$ (50 ng/ml), with or without cilostazol ($10{\mu}M$). Pretreatment with cilostazol markedly reduced TNF-${\alpha}$-induced viability loss in the HUVECs, which was reversed by zinc protoporphyrine IX (ZnPP), an inhibitor of HO-1. Moreover, cilostazol increased HO-1 protein and mRNA expression. Cilostazol-induced HO-1 induction was markedly attenuated not only by ZnPP but also by copper-protoporphyrin IX (CuPP). In an assay measuring peroxisome proliferator-activated receptor-${\gamma}$ (PPAR-${\gamma}$) transcription activity, cilostazol directly increased PPAR-${\gamma}$ transcriptional activity which was completely abolished by HO-1 inhibitor. Furthermore, increased PPAR-${\gamma}$ activity by cilostazol and rosiglitazone was completely abolished in cells transfected with HO-1 siRNA. Taken together, these results indicate that cilostazol up-regulates HO-1 and protects cells against TNF-${\alpha}$-induced endothelial cytotoxicity via a PPAR-${\gamma}$-dependent pathway.

• 센서학회지
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• 제24권1호
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• pp.15-21
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• 2015

Transparent and conductive multilayer thin films consisting of three alternating layers FZTO/Ag/$WO_3$ have been fabricated by radio-frequency (RF) sputtering for the applications as transparent conducting oxides and the structural and optical properties of the resulting films were carefully studied. The single layer fluorine doped zinc tin oxide (FZTO) and tungsten oxide ($WO_3$) films grown at room temperature are found to have an amorphous structure. Multilayer structured electrode with a few nm Ag layer embedded in FZTO/Ag/$WO_3$ (FAW) was fabricated and showed the optical transmittance of 87.60 % in the visible range (${\lambda}=380{\sim}770nm$), quite low electrical resistivity of ${\sim}10^{-5}{\Omega}cm$ and the corresponding figure of merit ($T^{10}/R_s$) is equivalent to $3.0{\times}10^{-2}{\Omega}^{-1}$. The resultant power conversion efficiency of 2.50% of the multilayer based OPV is lower than that of the reference commercial ITO. Asymmetric D/M/D multilayer is a promising transparent conducting electrode material due to its low resistivity, high transmittance, low temperature deposition and low cost components.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.168-168
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• 2010

Transparent conduction oxides (TCOs) films is extensively reported for optoelectronic devices application such as touch panels, solar cells, liquid crystal displays (LCDs), and organic light emitting diodes(OLEDs). Among the many TCO film, indium tin oxide(ITO) is in great demand due to the growth of flat panel display industry. However, indium is not only high cost but also its deposits dwindling. Therefore, many studies are being done on the transparent conductive oxides(TCOs). We fabricated a target of IZTO(In2O3:ZnO:SnO2=70:15:15 wt.%) reduced indium. Then, IZTO thin films were deposited on glass substrates by pulsed DC magnetron sputtering with various oxygen flow ratio. The substrate temperature was fixed at the room temperature. We investigated the electrical, optical, structural properties of IZTO thin films. The electrical properties of IZTO thin films were dependent on the oxygen partial pressure. As a result, the most excellent properties of IZTO thin films were obtained at the 3% of oxygen flow rate with the low resistivity of $7.236{\times}10^{-4}{\Omega}cm$. And also the optical properties of IZTO thin films were shown the good transmittance over 80%. These IZTO thin films were used to fabricated organic light emitting diodes(OLEDs) as anode and the device performances studied. The OLED with an IZTO anode deposited at optimized deposition condition showed good brightness properties. Therefore, IZTO has utility value of TCO electrode although it reduced indium and we expect it is possible for the IZTO to apply to flexible display due to the low processing temperature.

• 생명과학회지
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• 제15권2호
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• pp.231-235
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• 2005

기질 금속단백분해효소(MMP)는 기저막이나 간질성 조직 등에 있는 세포외기질 성분을 분해하여 상처 치유, 태아의 발생, 종양세포의 침윤과 전이 등을 포함하여 조직이 재구성되는 과정에서 생리학적 및 병리학적인 과정 양쪽 모두에 매우 중요한 역할을 한다. 본 연구에서는 MMP-9 유전자의 발현을 억제하는 물질을 천연물에서 탐색하였고, 탐색된 시료 중에서 높은 역가를 가진 낙우송과의 Metasequoia glyptostroboides가 선택되었다. 여러 가지 flavonoid 성분을 가지고 있는 Metasequoia glyptostroboides를 이용하여 4개의 biflavonoid와 2개의 monoflavonoid 구조의 물질을 분리하였고, 이 flavonoid들은 sciadopitysin, isoginkgetin, bilobetin, 2, 3-dihydrohino-kiflavone, luteolin, apigenin으로 정제하여 구조를 밝히고 zymography, WST-1을 이용한 세포독성시험, northern blot 등의 실험을 통하여 각 화합물의 구조적인 특성과 함께 MMP-9 유전자 발현을 억제하는 효과가 있는 것을 확인하였다.