• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.310-311
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• 2008

We have studied electro-optical characteristics of fringe-field switching (FFS) mode with high $d{\Delta}n$ according to the electrode position. In this device, the fringe-electric field drives the LCs to rotate so that the dielectric torque is electrode-positional dependent, which results in electrode-position dependency in the LC's rotating angle. We confirmed polarization microscope image and chromaticity diagram at the different electrode position with LC that have high $d{\Delta}n$. Since the FFS mode is influenced by horizontal and vertical electric field, the FFS mode modulates light using both phase retardation and polarization rotation effect, which had already been verified with previous studies. However, from another point of view, tight modulation of FFS mode has been demonstrated by performing experiment and calculated simulation at the high $d{\Delta}n$ LC cell.

• 한국과학교육학회지
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• 제35권3호
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• pp.465-475
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• 2015

본 연구의 목적은 과학과 국가수준 학업성취도 평가에서 물리의 광학 영역 문항의 평가 결과를 분석하고 답지 반응률 분포 곡선을 활용하여 중학생들의 반응 특성을 분석하는 것이다. 이를 위해서 2010년부터 2013년까지 중학생들을 대상으로 시행된 과학과 국가수준 학업성취도 평가의 물리 문항 중 광학 영역에 해당되는 10개 문항을 분석하였다. 분석 결과는 다음과 같다. 첫째, 학생들의 '광학' 영역의 성취수준은 다른 영역(역학, 전자기학)에 비해서는 높았다. 둘째, '빛' 영역에서 '상의 형성'과 관련되어 학생들이 낮은 성취수준을 보였으며, '파동' 영역에서는 '파동의 전파에서 위상의 변화'와 관련되어 낮은 성취수준을 나타내었다. 셋째, 학생들은 상황 의존적인 문제풀이 전략 및 결과를 보이고 있었다. 연구 결과를 바탕으로 광학 개념에 대한 교육과정 수준의 재검토, 기초학력 단계 학생들에 대한 추가적인 교수학습의 필요성, 실제적인 현상 및 상황 중심의 교수학습의 필요성 등의 제언을 논의하였다.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.352-355
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• 2002

The purpose of this study was to investigate whether or not acupuncture of GB34 produces a significant response of the modulation of somatomotor areas by functional magnetic resonance imaging (fMRI) study. The acupoint, GB34, located in the back of the knee, is known to be effective in recovering motor function after stroke. Using 3T MRI scanner, functional MR imaging of the whole brain was performed in 12 normal healthy subjects during two stimulation paradigms; acupuncture manipulation on GB 34 and sham points. This study investigates the activation of the mortor cortex elicited by a soft and an intensified stimulation of GB 34. Three different paradigms were carried out to detect any possible modulation of the Blood Oxygenation Level Dependent (BOLD) response in the somatomortor area to motor stimulation through acupuncture. Group analysis from seven individuals showed that bilateral sensorimotor areas (BA 3,4,6 and 7) showed stimulation related BOLD signal contrast of approximately 6% whereas very few areas were activated when sham stimulation is given. The present study shows that acupuncture fMRI study can be safely conducted in 3T MRI environment, and acupuncture stimulation in GB34 modulates the cortical activities of the somatomotor area in human. The present findings may shed light on the CNS mechanism of motor function by acupuncture and form a basis for future investigations of motor modulation circuits in the stroke patients.

• Advances in Energy Research
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• 제2권1호
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• pp.33-45
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• 2014

Photocatalytic hydrogen generation by water splitting ($H_2O_{(1)}{\rightarrow}H_2_{(g)}+1/2O_2_{(g)}$) has been studied on photocatalysts based on Zn, Cd, Fe and Cu, synthesized by coprecipitation. Iron and copper nanoparticles were incorporated as cocatalysts to enhance the photocatalytic activity of the ZnCd solid solution. The effect of the different synthesis parameters (temperature, elemental atomic ratios, amount of Cu and Fe incorporated in the catalyst and calcination temperature) on the photocatalytic production of hydrogen has been studied in order to determine the best experimental synthesis conditions. The catalysts have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and BET. The experiments of photocatalytic water splitting were performed in aqueous solution of the photocatalysts previously dispersed in a soft ultrasound bath. The photocatalysts were irradiated under different lights ranging from 220 to 700 nm. The photocatalytic activity was found to be clearly dependent on the specific area of the photocatalyst.

• Asian Pacific Journal of Cancer Prevention
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• 제15권4호
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• pp.1851-1857
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• 2014

Objective: The main purpose of this work was to investigate the effect of berberine hydrochloride (BH) on the proliferation, apoptosis, migration, and invasion of CNE-1 nasopharyngeal carcinoma cells. Our results shed light on the functional components of traditional Chinese herbs for potential use in modern medicine. Methods: The CNE-1 cell line was treated with different concentrations of BH and effects on cell viability and proliferation were evaluated using the Cell Counting Kit-8 (CCK-8) assay. Anti-migratory and anti-invasive actions of BH were investigated using wound healing assays and the Millicell Hanging cell culture insert system, respectively. Expression of the epithelial-mesenchymal transition (EMT)-related gene twist (Twist) was analyzed by real-time PCR and Western blotting. Apoptosis was estimated with an annexin-V fluorescein (FITC) apoptosis detection kit, as well as with reference to levels of activated caspase-3 of CNE-1 cells before and after treatment with BH utilizing fluorescence spectroscopy. Results: BH was capable of reducing proliferation and viability of CNE-1 cells in a dose- and time-dependent manner, also demonstrating anti-migratory and anti-invasive capacities which correlated with reduction in expression of Twist. Finally, BH was able to induce significant amounts of apoptosis in CNE-1 cells, as demonstrated by an increase in the activity of caspase-3 and in annexin-V staining following treatment. Conclusion: BH extracted from rhizoma coptidis demonstrated an ability to block proliferation, induce apoptosis, and impair the migration and invasion of the CNE-1 cell line Considering these properties, our results suggest that BH could be an important compound for consideration in the treatment of nasopharyngeal carcinoma.

• 마이크로전자및패키징학회지
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• 제10권3호
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• pp.43-55
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• 2003

최근 IT산업의 발달과 그에 따른 전자부품기술의 발전이 가속화됨에 따라, 전자부품의 경박 단소화 및 고성능에 대한 요구는 전자패키지 (electronic package) 및 반도체기판(PKG substrate) 업체들로 하여금 고밀도의 입출력(I/O)과 우수한 열적, 전기적 특성을 보유하면서 높은 양산수율로 제품이 가격경쟁력을 갖도록 유도하고 있다. 이러한 경향에 따라 세계적인 반도체 회사(chip-maker)들은 더욱 혹독한 조건의 신뢰성 표준을 마련하여 제반 산업에 전반적인 적용을 요구하고 있으며, 환경친화 및 고주파, 고성능의 특성을 지닌 새로운 소재를 개발하도록 촉구하고 있는 실정이다. 반도체기판은 구성소재에 따라 구현되는 특성의 범위가 매우 크므로 우수한 특성의 소재를 반도체기판에 적용할 때 고객의 요구조건에 충분히 만족시킬 수 있을 것으로 기대된다. 따라서, 기판업계에서는 우수한 특성을 나타내는 원자재의 개발 및 수급이 절실하게 되었으며 급변하는 원자재의 기술 동향에 대한 분석은 향후 전자패키지 및 기판제품의 경쟁력을 향상시킬 수 있을 것이므로 본 연구에서는 최신 반도체기판 원자재의 기술 동향과 원자재의 특성을 분석하고자 하였다.

• Animal cells and systems
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• 제16권5호
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• pp.366-375
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• 2012

Gallotannin (GT) is derived from plant poly phenol and is associated with biological actions in a wide range of cells. In this study, we evaluated the effect of GTon apoptosis and cyclooxygenase-2 (COX-2) expression and attempted to shed light on the mechanism of action in A549 human lung carcinoma cells. We found that GT dramatically induced apoptosis as demonstrated by expression of p53 and active caspase-3 via western blot analysis and fragmented DNA as detected by DNA fragmentation and DAPI staining. We also observed that GT significantly causes COX-2 expression in a dose-dependent manner determined by western blot analysis. Phosphorylation of Akt and p38 was considerably increased by GT in A549 human lung carcinoma cells. Inhibition of Akt and p38kinase with LY294002 or SB203580 suppressed GT-induced apoptosis and COX-2 expression. Furthermore, we have shown that prevention of COX-2 with NS398 or indomethacin does not any effects on apoptosis induced by GT. Taken together, our present results suggest that GT regulates apoptosis and COX-2 expression through Akt and p38kinase pathway in A549, human lung carcinoma cells.

• 한국작물학회지
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• 제49권1호
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• pp.12-18
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• 2004

Activity of senescence-induced antioxidant enzymes in the detached rice seedlings (Oryza sativa L. cv. Dongjin) was examined. The levels of $\textrm{H}_2\textrm{O}_2$ content and peroxidase (POD) activity were gradually increased during leaf senescence, whereas catalase activity was decreased. The activity of superoxide dismutase (SOD) was increased, and ascorbate peroxidase (APX) and glutathione reductase (GR) were slightly increased until 3d and 4d of dark induced-senescence, and thereafter were decreased. The activation of all SOD isoforms showed a significant decrease after 6d and 7d. After 4d to 7d of dark senescence, there was a significant effect in enhancing the activity of APX-12 and -13 isoforms as compared with light, despite similar levels in total APX activity. GR-8 and -10 isoforms were more effective in leaf senescence at 4d to 7d, particularly with respect to dark-induced senescence. These results suggest that the metabolism of active oxygen species such as $\textrm{H}_2\textrm{O}_2$ is dependent on various functionally interrelated antioxidant enzymes such as catalase, peroxidase, SOD, APX and GR.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.235-235
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• 2017

Chromium (Cr) toxicity is hazardous to the seed germination, growth, and development of plants. ${\gamma}$-Aminobutyric acid (GABA) is a non-protein amino acid and is involved in stress tolerance in plants. To investigate the effects of GABA in alleviating Cr toxicity, we treated eight-d-old mustard (Brassica juncea L.) seedlings with Cr (0.15 mM and 0.3 mM $K_2CrO_4$, 5 days) alone and in combination with GABA ($125{\mu}M$) in a semi-hydroponic medium. The roots and shoots of the seedlings accumulated Cr in a dose-dependent manner, which led to an increase in oxidative damage [lipid peroxidation; hydrogen peroxide ($H_2O_2$) content; superoxide ($O{_2}^{{\cdot}-}$) generation; lipoxygenase (LOX) activity], MG content, and disrupted antioxidant defense and glyoxalase systems. Chromium stress also reduced growth, leaf relative water content (RWC), and chlorophyll (chl) content but increased phytochelatin (PC) and proline (Pro) content. Furthermore, supplementing the Cr-treated seedlings with GABA reduced Cr uptake and upregulated the non-enzymatic antioxidants (ascorbate, AsA; glutathione, GSH) and the activities of the enzymatic antioxidants including ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione peroxidase (GPX), superoxide dismutase (SOD), catalase (CAT), glyoxalase I (Gly I), and glyoxalase II (Gly II), and finally reduced oxidative damage. Adding GABA also increased leaf RWC and chl content, decreased Pro and PC content, and restored plant growth. These findings shed light on the effect of GABA in improving the physiological mechanisms of mustard seedlings in response to Cr stress.

• 한국치위생학회지
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• 제15권4호
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• pp.719-725
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• 2015

Objectives: The purpose of this study was to determine the toxic effects of sodium lauryl sulfate(SLS) in human keratinocyte HaCaT cells and mouse fibroblast NIH-3T3 cells. Methods: The effect of sodium lauryl sulfate(SLS) cell viability and proliferation were determined by WST-1 assay and changes shape of nucleus were evaluated by Hoechst staining under fluorescence microscopy. Additionally, observation of cell morphological changes under light microscopy. Results: SLS induced cytotoxicity and a marked apoptosis in both HaCaT and NIH-3T3 cell lines. With the result of the WST-1 assay, SLS induced the cytotoxicity of 0.005% and 0.0075%, 0.01% SLS for 24 h after HaCaT and NIH-3T3 cells in time and dose-dependent manner(p<0.005). SLS inhibited cell growth and caused apoptosis as evidenced by nuclear fragmentation and condensation. Thus, determination of the morphological changes to define apoptosis was visualized using inverted phase contrast microscopy. Conclusions: SLS had toxicity of the human keratinocyte cells and mouse fibroblast cells and this study will provide the basic data for the development of proper SLS concentration in dentifrice.