• BMB Reports
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• v.39 no.5
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• pp.530-536
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• 2006

Thermal conformational changes of human serum albumin (HSA) in phosphate buffer, 10 mM at pH = 7 are investigated using differential scanning calorimetric (DSC), circular dichroism (CD) and UV spectroscopic methods. The results indicate that temperature increment from $25^{\circ}C$ to $55^{\circ}C$ induces reversible conformational changes in the structure of HSA. Conformational change of HSA are shown to be a three-step process. Interestingly, melting temperature of the last domain is equal to the maximum value of fever in pathological conditions, i.e. $42^{\circ}C$. These conformational alterations are accompanied by a mild alteration of secondary structures. Study of HSA-SDS (sodium dodecyl sulphate) interaction at $45^{\circ}C$ and $35^{\circ}C$ reveals that SDS affects the HSA structure at least in three steps: the first two steps result in more stabilization and compactness of HSA structure, while the last one induces the unfolding of HSA. Since HSA has a more affinity for SDS at $45^{\circ}C$ compared to $35^{\circ}C$, It is suggested that the net negative charge of HSA is decreased in fever, which results in the decrease of HSA-associated cations and plasma osmolarity, and consequently, heat removal via the increase in urine volume.

• Journal of Surface Science and Engineering
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• v.45 no.1
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• pp.20-24
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• 2012

Multilayer passivation film on OLED with organic/inorganic hybrid structure as to diminish the thermal stress and expansion was researched to protect device from the direct damage of $O_2$ and $H_2O$ and improve life time characteristics. Red OLED doped with 1 vol.% Rubrene in $Alq_3$ was used as a basic device. The films consist of ITO(150 nm)/ELM200_HIL(50 nm)/ELM002_HTL(30 nm)/$Alq_3$: 1 vol.% Rubrene(30 nm)/$Alq_3$(30 nm) and LiF(0.7 nm)/Al(100 nm) which were formed in that order. Using LiF/$SiN_x$ as a buffer layer was determined because it significantly improved life time characteristics without suffering damage in the process of forming passivation film. Multilayer passivation film on buffer layer didn't produce much change in current efficiency, while the half life time at 1,000 $cd/m^2$ of OLED/LiF/$SiN_x$/E1/$SiN_x$ was 710 hours which showed about 1.5 times longer than OLED/LiF/$SiN_x$/E1 with 498 hours. futhermore, OLED/LiF/$SiN_x$/E1/$SiN_x$/E1/$SiN_x$ with 1301 hours showed about twice than OLED/LiF/$SiN_x$/E1/$SiN_x$ which demonstrated that superior characteristics of life time was obtained in multilayer passivation film. Through the above result, it was suggested using LiF/$SiN_x$ as a buffer layer could reduce the damage from the difference of thermal expansion coefficient in OLED with protective films, and epoxy layer in multilayer passivation film could function like a buffer between $SiN_x$ inorganic layers with relatively large thermal stress.

• Natural Product Sciences
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• v.23 no.1
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• pp.35-39
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• 2017

D-chiro-inositol (DCI) is a secondary messenger in insulin signal transduction. It is produced in vivo from myo-inositol via action of epimerase. In this study, we evaluated antitumor activity of DCI against human breast cancer both in vitro and in vivo. In order to determine the inhibitory effects of DCI on growth of human breast cancer cells (MDA-MB-231), two different assessment methods were implemented: MTT assay and mouse xenograft assay. MTT assay demonstrated downturn in cell proliferation by DCI treatment (1, 5, 10, 20 and 40 mM) groups by 18.3% (p < 0.05), 17.2% (p < 0.05), 17.5% (p < 0.05), 18.4% (p < 0.05), and 24.9% (p < 0.01), respectively. Also, inhibition of tumor growth was investigated in mouse xenograft model. DCI was administered orally at the dose of 500 mg/kg and 1000 mg/kg body weight to treat nude mouse for 45 consecutive days. On the 45th day, tumor growth of DCI (500 mg/kg and 1000 mg/kg) groups was suppressed by 22.1% and 67.6% as mean tumor volumes were $9313.8{\pm}474.1mm^3$ and $3879.1{\pm}1044.1mm^3$, respectively. Furthermore, breast cancer stem cell (CSC) phenotype ($CD44^+/C24^-$) was measured using flow cytometry. On the 46th day, CSC ratios of DCI (500 mg/kg) and co-treatment with doxorubicin (4 mg/kg) and DCI (500 mg/kg) group decreased by 24.7% and 53.9% (p < 0.01), respectively. Finally, from tumor recurrence assay, delay of 5 days in the co-treatment group compared to doxorubicin (4 mg/kg) alone group was observed. Based on these findings, we propose that DCI holds potential as an anti-cancer drug for treatment of breast cancer.

• Food Science and Preservation
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• v.13 no.6
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• pp.703-707
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• 2006

The propose of this study was to investigate the changes of available components in Chajogi (Perilla sikokiana B.) by different harvest periods. The Chajogi samples were divided into four groups by harvest period. The four groups were divided into I (harvesting sample at 14, July, 2005), II (harvesting sample at 25, July, 2005), III (harvesting sample at 15, Aug, 2005) and IV sample (harvesting sample at 2, Sept, 2005), and then analysed with regard to the content of proximate compositions, minerals, amino acids, perillaldehyde and anthocyanin. The contents of reducing sugar increased with increasing harvesting periods, while those of crude protein, crude lipid and total amino acids decreased for IV sample as compared to the other samples. The levels of heavy metals in all samples were not detected. The Zn, Fe and Mg contents of IV sample decreased sharply. The perilladehyde contents were 0.36%, 0.42% 0.45%, and 0.35% for I, II, III, and IV products, respectively. III sample as contented to the other samples was shown to have the highest anthocyanine content (1.21% in dry basis). In conclusion, the date of harvesting Chajogi affects the contents of available components.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.45.1-45.1
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• 2009

과학기술위성 3호의 주탑재체인 MIRIS (Multi-purpose InfraRed Imaging System)는 우주관측카메라 (Space Observation Camera, SOC)와 지구관측카메라 (Earth Observation Camera, EOC)가 독립적인 시스템으로 구성되어 있다. 지구관측카메라는 유효 구경 100 mm, F/5의 광학계로 3-5 마이크론 파장영역을 관측하며, 국내에서 개발된 적외선 검출기의 우주 인증 시험과 유사시 한반도 적외선 감시를 주요 목적으로 하고 있다. 고도 700km에서 지상을 볼 때 약 42m/pixel의 공간분해능을 나타낼 것으로 기대하고 있다. 지구관측카메라의 인증 모델(Qualification Model)은 냉동기를 제외한 모든 부품이 국내기술로 제작되었으며, 미러 본딩 및 릴레이 렌즈 조립 기술, 적외선 영상 검교정 기술 등 다양한 경험과 도전을 제공했다. 이 발표에서는 지구관측카메라 인증모델을 이용하여 수행한 주요 시험 과정을 소개한다. 국내 회사 (주)i3 system에서 제작된 적외선 검출기는 $320\times256$ HgCdTe array (평균 양자효율 80% 이상) 이며 77K에서 정상적으로 운영된다. Micro Stirling Cooler에 의해 듀어는 전원을 켠 후 5분 이내에 검출기 운영온도인 77K까지 내려간다. 적외선 광학계의 정렬, 시스템 MTF 측정, 흑체 측정 및 검교정 작업을 수행한 후 야외에서 다양한 경우에 대해 Field Test를 진행했다. 이 발표에서는 Field Test 과정과 이를 통해 얻은 결과를 발표하고, FM (Flight Model) 제작에 있어 수정해야 할 사항들을 제안해 본다.

• Journal of Information Display
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• v.4 no.2
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• pp.1-6
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• 2003

In this paper, we demonstrate that the organic electrophosphorescent device is driven by the organic thin film transistor with spin-coated photoacryl gate insulator. It was found that electrical output characteristics in our organic thin film transistors using the staggered-inverted top-contact structure showed the non-saturated slope in the saturation region and the sub-threshold nonlinearity in the triode region, where we obtained the maximum power luminance that was about 90 $cd/m^2$. Field effect mobility, threshold voltage, and on-off current ratio in 0.45 ${\mu}m$ thick gate dielectric layer were 0.17 $cm^2/Vs$, -7 V, and $10^6$ , respectively. In order to form polyimide as a gate insulator, vapor deposition polymerization process was also introduced instead of spin-coating process, where polyimide film was co-deposited by high-vacuum thermal evaporation from 4,4'-oxydiphthalic anhydride (ODPA) and 4,4'-oxydianiline (ODA) and cured at 150${\sqsubset}$for 1hr. It was also found that field effect mobility, threshold voltage, on-off current ratio, and sub-threshold slope with 0.45 ${\mu}m$ thick gate dielectric films were 0.134 $cm^2/Vs$, -7 V, and $10^6$ A/A, and 1 V/decade, respectively.

• KIEAE Journal
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• v.7 no.6
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• pp.37-43
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• 2007

Discomfort glare is an important factor influencing appraisal for lighting environment. Unified Glare Rating (UGR) which has been proposed by CIE is one of the formula for evaluating discomfort glare. Position index is an important factor in the UGR formula. Position index was proposed by Guth in 1949. It has been used until present limiting upper visual field. Lower visual field has different sensation of brightness in comparing with upper visual field. Therefore, it is necessary to propose position index about lower visual field. The objective of this study is to investigate the brightness sensation in upper and lower visual field. First, the visual field was measured on the self-made Glare Tester. Second, luminance of the Borderline between Comfort and Discomfort (BCD) was measured on the glare Tester. Circular sources of brightness were located at various angular distances from the line of vision along five meridians, $0^{\circ}$, $45{\circ}$, $90{\circ}$, $-45{\circ}$, $-90{\circ}$. The size of the glare source is 0.0011sr. The luminance of the surrounding field, which extended over the entire visual field, was maintained $34ccd/m^2$. Ten subjects aged from 25 to 29 were participated in the experiment. The results show that the luminance of BCD on the line of vision is $4337cd/m^2$ and the glare sensation of the lower visual field is more sensitive than the upper visual field.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.6
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• pp.801-806
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• 2009

A species producing transglutaminase (EC 2.3.2.13) was isolated from forest soil and identified as Streptomyces platensis YK-2. The transglutaminase was purified from culture broth by 50% methanol precipitation, followed by successive chromatography on DEAE-Sephadex. The yield and purification-fold was 63.4% and 2.2-fold, respectively. The purified microbial transglutaminase (MTG) migrated as a single band of approximately 45 kDa upon sodium dodecyl sulfate polyacrylamide gel eletrophoresis. The isoelectric point determined by multichambered electrofocusing was pH $6.0{\sim}7.0$. The enzyme was strongly inhibited by $Hg^{++}$, but was activated by $Cd^{++}$, $Mg^{++}$, $Mn^{++}$, $Pb^{++}$ and reducing agents such as dithiothreitol and mercaptoethanol.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.5
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• pp.393-398
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• 2019

A poly[bis(4-butypheny)-bis(phenyl)benzidine] (poly-TPD) and poly(9-vinylcarbazole) (PVK) bilayer was employed as a hole transport layer (HTL) in solution-processed CdSe/ZnS quantum dot light-emitting diodes (QLEDs). The thickness of the PVK layer spin-coated onto the poly-TPD layer, whose thickness was fixed to 40 nm, was varied, with PVK layer thicknesses of 0 nm, 35 nm, 45 nm, and 55 nm. Because the thickness of the PVK can determine the hole transport properties of the HTL, a PVK thickness that maximizes the performance of the HTL for the QLEDs was investigated. By employing the optimized PVK thickness of 45 nm, the current efficiency of the QLED exhibited a 1.74 times improvement when compared with that of the QLED with poly-TPD based HTL without PVK. This was mainly attributed to the decrease in the energy barrier between the HTL and the quantum dot (QD) emitting layer (EML).

• Tuberculosis and Respiratory Diseases
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• v.48 no.5
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• pp.757-765
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• 2000

Background : Angiogenesis plays a critical role in human tumor growth and metastasis. Microvessel count as a measure of tumor angiogenesis, has been significantly correlated with invasive and metastatic patterns in breast. prostate and cutaneous carcinomas. Materials and Methods : Fifty patients with curatively resected non-small cell lung cancer were evaluated. Tumor tissues embedded in paraffin block were stained by anti CD 31 (PECAM, platelet endothelial cellular adhesion molecule) using immunohistochemical method to assess microvessel count. Microvessels were counted in the most active areas of neovascularization(microscopy, 200$\times$). Results: 1) Mean microvessel count was 47.1$\pm$17.7(per 200$\times$field) in total 50 cases. 2) Mean microvessel count of adenocarcinoma (54.4$\pm$19.9) was significantly higher than that of squamous cancer (43.9$\pm$16.2) (p<0.05), but there were no relationship between microvessel count and TNM stages. 3) Median survival time, 2-year and 5-year survival rates of the low microvascular group (microvessel count<45, 22 cases) were 61 months, 80% and 40%, respectively, and those of the high microvascular group(microvessel count$\geq$45, 28 cases) were 46 months, 75% and 12%, respectively. As results, prognosis of low microvascular group is statistically significantly superior to that of the high microvascular group (p=0.0162, Kaplan-Meier, log-rank). Conclusion : Angiogenesis assessed by microvessel count can be used as one of the significant prognostic factors in non-small cell lung cancer.