• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1275-1276
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• 2007

For fabrication of $BaTiO_3$ system Ferroelectric thick films, (Ba,Sr,Ca)$TiO_3$ (BSCT) powders, prepared by using the alkoxide-based sol-gel method, were doped $MnCO_3$ as acceptor and $Dy_{2}O_{3}$ as donor. $MnCO_3$ and $Dy_{2}O_{3}$-doped (Ba,Sr,Ca)$TiO_3$ thick films were fabricated by screen printing techniques on high purity alumina substrates. The structure and dielectric properties were investigated with variation of $Dy_{2}O_{3}$ amount. As a result of the differential thermal analysis(DTA), exothermic peak was observed at around $670^{\circ}C$ due to the formation of the polycrystalline perovskite phase. All the BSCT thick films, sintered at $1420^{\circ}C$ for 2h, showed the typical XRD patterns of perovskite polycrystalline structure and no pyrochlore phase was observed. The average grain size and thickness of specimens no doped with $Dy_{2}O_{3}$ was 1.32mm, 52mm, respectively. The relative dielectric constant decreased and dielectric loss increased with increasing amount of $Dy_{2}O_{3}$ dopant, the values of the BSCT thick films no doped with $Dy_{2}O_{3}$ were 4043 and 0.4% at 1 kHz, respectively. The relative dielectric constant gradually decreased in the measured frequency range from 0.1 to 100 kHz

• The Plant Pathology Journal
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• v.24 no.3
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• pp.322-327
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• 2008

Antifungal activities of natural substrances from Eucalyptus darlympleana, E. globules, E. gunnii and E. unigera were evaluated against postharvest pathogens of kiwifruits, Botrytis cinerea, Botryosphaeria dothidea, and Diaporthe actinidiae, to screen effective natural substances as an alternative to chemical fungicides. Methanol extract of the Eucalyptus trees showed strong antagonistic activity against the pathogenic fungi. Among them, E. unigera and E. darlympleana effectively inhibited mycelial growth of the pathogens. For chemical identification of the antifungal substances, the methanol extract of E. darlympleana leaves was successively partitioned with $CH_2Cl_2$, EtOAc, n-BuOH and $H_2O$. Among the fractions, $CH_2Cl_2$ and n-BuOH showed strong inhibitory activity of mycelial growth of the fungi. Five compounds were isolated from EtOAc and n-BuOH fractions subjected to $SiO_2$ column chromatography. Two phenolic compounds(gallic acid and 3,4-dihydroxybenzoic acid) and three flavonoid compounds(quercetin, quercetin-3-O-$\alpha$-L-rhamnoside, quercetin-3-O-$\beta$-glucoside) were identified by $^1H$-NMR and $^{13}C$-NMR spectroscopy. Among them, only gallic acid was found to be effective in mycelial growth and spore germination of B. cinerea at relatively high concentrations. The results suggest that gallic acid can be a safer and more acceptable alternative to current synthetic fungicides controlling soft rot decay of kiwifruit during postharvest storage.

• Korean Journal of Medicinal Crop Science
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• v.8 no.4
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• pp.342-350
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• 2000

This study was carried out to screen antioxidative by in vitro bioassay method from 89 Korean natural sources extracted by 100% MeOH. Antioxidant activity test was used the DPPH method. MeOH extracts from Castanea crenata and Ulmus davidiana var. japonica showed high antioxidant activity by $5.8{\mu}g\;(RC_{50})$ and $12.2{\mu}g\;(RC_{50})$, respectively, among 13 plants exhibiting the activity. The extracts from Platycarya strobilacea, Lindera erythrocarpa, Chrysanthemum boreale, Rumex crispus and Viburnum awabuki also showed over 90% antimicrobial activity, according to in vivo bioassay method.

• Korean Journal of Digital Imaging in Medicine
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• v.9 no.1
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• pp.37-43
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• 2007

1. Purpose : This study is to present effective exposure conditions to acquire the best image of simple abdomen in Film Screen (F.S) system and Computed Radiography (C.R) system. 2. Method : In the F.S system, while an exposure condition was fixed as 70kVp, images of a patients simple abdomen were taken under the different mAs exposure conditions. Among these images, the best one was chosen by radiologists and radiological technologists. In the C.R system, the best image of the same patient was acquired with the same method from the F.S system. Both characteristic curves from F.S system and C.R system were analyzed. 3. Results : In the F.S system, the best exposure condition of simple abdomen was 70kVp and 20mAs. In the CR system, with the fixed condition at 70kVp, the image densities of human organs, such as liver, kidney, spleen, psoas muscle, lumbar spine body and iliac crest, were almost same despite different environments (3.2mAs, 8mAs, 12mAs, 16mAs and 20mAs). However, when the exposure conditions were over or under (below) 12mAs, the images between the abdominal wall and the directly exposed part became blurred because the gap of density was decreased. In the C.R system, while the volume of mAs was decreased, an artifact of quantum mottle was increased. 4. Conclusion : This study shows that the exposure condition in the C.R system can be reduced 40% than in the F.S system. This paper concluded that when the exposure conditions are set in CR environment, after the analysis of equipment character, such as image processing system(EDR : Exposure Data Recognition processing), PACS and so on, the high quality of image with maximum information can be acquired with a minimum exposure dose.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.4
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• pp.1028-1035
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• 2004

Imperatorin, a biologically active furanocoumarin from the roots of Angelica dahurica (Umbelliferae), was mutagenic and induced transformation of mouse fibroblast cell lines, whereas it provided inhibiting effects on mutagenesis and carcinogenesis induced by various carcinogens. Furthermore, it has been suggested that imperatorin may have potential anticarcinogenic effects when administered orally in the diet. In addition to its anticarcinogenic properties, imperatorin has been shown to possess anticancer activities. We investigated the macro scale gene expression analysis on the HL-60 cells treated with imperatorin. Imperatorin (10μM) were used to treat the cells for 6h, 12h, 24h, 48h, and 72h. In a human cDNAchip study of 10,000 genes evaluated 6, 12, 24, 48, 72 hours after treated with imperatorin in HL-60 cells. Hierarchical cluster against the genes which showed expression changes by more than 2 fold. Three hundred eighty six genes were grouped into 6 clusters by a hierarchical clustering algorithm. Pathway analysis using gene microarray pathway prof Her that is a computer application designed to visualize gene expression data on screen representing biological pathways and groupings of genes.

• Korean Journal of Pharmacognosy
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• v.34 no.2 s.133
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• pp.138-141
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• 2003

In order to screen new tyrosinase inhibiting principle which is expected to be a new biofunctional skin whitening cosmetics, we have isolated 600 strains of the marine- derived fungi and investigated tyrosinase inhibiting activity for their acetone extracts. The significant activities (>70% Inhibition) were observed in the extract of 10 strains of fungi (MFA7, MFA27, MFA58, MFA317, MFA318, MFA345, MFA412, MFA552, MFA562, MFA581). These active strains were cultured in SWS medium with 1 L scale and the resulting broth and mycelium were extracted to afford mycelium extract (000M) and broth extract (000B), respectively. Tyrosinase inhibiting activity for all extracts has been tested. As the results, the broth extracts of 4 strains (27B, 58B, 552B and 581B) exhibited relatively high levels of activity of $IC_{50}$ values of $3.0-19.0\;{\mu}g/mL$. The active component of 581B was purified by assay-guided isolation to yield the known kojic acid (1), and its structure was determined by physicochemical evidence. Kojic acid showed the significant tyrosinase inhibitory activity with $IC_{50}$ values of $12.0\;{\mu}M$.

• Korean Journal of Materials Research
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• v.22 no.2
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• pp.103-109
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• 2012

Red-emitting $Eu^{3+}$-activated $(Y_{0.95-x}Al_x)VO_4$ (0 < x $\leq$ 0.12) nanophosphors with the particle size of ~30 nm and the high crystallinity have been successfully synthesized by a hydrothermal reaction. In the synthetic process, deionized water as a solvent and ethylene glycol as a capping agent were used. The crystalline phase, particle morphology, and the photoluminescence properties of the excitation spectrum, emission intensity, color coordinates and decay time, of the prepared $(Y_{0.95-x}Al_x)VO_4:Eu^{3+}$ nanophosphors were compared with those of the $YVO_4:Eu^{3+}$. Under 147 nm excitation, $(Y_{0.95-x}Al_x)VO_4$ nanophosphors showed strong red luminescence due to the $^5D_0-^7F_2$ transition of $Eu^{3+}$ at 619 nm. The luminescence intensity of $YVO_4:Eu^{3+}$ enhanced with partial substitution of $Al^{3+}$ for $Y^{3+}$ and the maximum emission intensity was accomplished at the $Al^{3+}$ content of 10 mol%. By the addition of $Al^{3+}$, decay time of the $(Y,Al)VO_4:Eu^{3+}$ nanophosphor was decreased in comparison with that of the $YVO_4:Eu^{3+}$ nanophosphor. Also, the substitution of $Al^{3+}$ for $Y^{3+}$ invited the improvement of color coordinates due to the increase of R/O ratio in emission intensity. For the formation of transparent layer, the red nanophosphors were fabricated to the paste with ethyl celluloses, anhydrous terpineol, ethanol and deionized water. By screen printing method, a transparent red phosphor layer was formed onto a glass substrate from the paste. The transparent red phosphor layer exhibited the red emission at 619 nm under 147 nm excitation and the transmittance of ~80% at 600 nm.

• Korean Journal of Agricultural Science
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• v.22 no.2
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• pp.188-196
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• 1995

To obtain useful mould strain in soybean fermentation industry, we collected conventional Meju all over the Korea and tested existance of aflatoxin in Meju collected. Also, we measured distribution of microorganism and enzyme activity of Meju and isolated Aspergillus oryzae O4-5 as a industrially useful mould. The results obtained were summarized as follows: 1. Aflatoxin was not detected by EZ-Screen Test Kit and HPLC analysis in various Meju sample collected all over the Korea from 1994.12 to 1995.2. 2. Colony forming units(CFU) of mould, yeasts, aerobe, and anaerobe were $1.3{\times}10^4-2.8{\times}10^6$, $1{\times}10^2-1.5{\times}0^6$, $2.0{\times}10^7-8.0{\times}10^8$ and $3.0{\times}10^6-7.3{\times}10^8$ per gram of Meju, respectively, indicating that CFU inter Meju samples were varied with big difference. 3. The activities of ${\alpha}$-amylase and gluco-amylase were 5-80 units and 2-34 units per g of Meju, respectively. It was shown that enzyme activity was varied depending on where the Meju was collected. 4. The activities of acidic, neutral and alkaline protease were 5-33 units, 5-302 units and 5-363 units per g of Meju, respectively. Acidic protease of Improved Meju made by D-Company was higher than that of conventional Meju as 66 units per g of Meju. 5. CNU O4-5 strain selected as a noble strain could produce amylase and protease in high level, and identified as a strain that belongs to Aspergillus oryzae. 6. The activities of acidic and neutral protease of Aspergillus oryzae CNU O4-5 strain isolated were about 10% higher than those of Aspergillus oryzae JM which has been used in soybean fermentation industry. Amylase activity of CNU O4-5 strain was similar to Aspergillus oryzae JM.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.22 no.4
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• pp.262-270
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• 2011

Objectives : The definition of a hidden youth is a young person who has completely withdrawn from society and shut himself or herself away for more than 3 months. Those pathologically-withdrawn youths have become a burden not only to society but also to the family. However, screening of these hidden youths cannot be done easily. This study focused on developing a primary effective screening tool for these hidden youths. Methods : The 42 participants of this study were parents of hidden youths that are between 8 to 25 years old. They were selected from from mental health centers and psychiatric clinics around Seoul and Gyeonggi Province. We also recruited 239 parents of middle and high school students in the Seoul metropolitan area for a control group. In order to decide the concurrent validity of this questionnaire, we used the Symptom Checklist-90-Revision, Children's Depression Inventory, Beck Depression Inven-tory, Social Anxiety Scale for Children-Revised, Social Anxiety and Distress Scale, Avoidant Personality Disorder Scale, and State-Trait Anxiety Inventory for Children. SPSS version 12.0 was used for statistical analysis. Results : Cronbach's alpha values, the reliability coefficient to represent internal consistency, were between 0.396 and 0.935, which showed relatively high internal consistency for this questionnaire. The test-retest coefficient was between 0.68 and 0.78, which was a statistically significant result. In a factor analysis, 4 factors such as avoidance, withdrawal, isolation, and apathy were extracted. In a concurrent validity test with SCL-90-R, the isolation factor showed a statistically-significant relationship with a phobic-anxiety sub-scale, and avoidance and withdrawal sub-scales were remarkably correlated with the interpersonal sensitivity sub-scale. Conclusion : Since the questionnaire for socially withdrawn youths has achieved statistically-satisfactory reliability and validity, it will be a useful method to screen for hidden youths in educational, community, and clinical settings.

• Korean Journal of Plant Resources
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• v.21 no.1
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• pp.12-18
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• 2008

Antioxidative activity and inhibitory activity of angiotensin I converting enzyme(ACE), aminopeptidase N(APN) and $\alpha$-amylase were investigated in the methanol extracts from 25 fern plants native to Jeju Island, in order to screen the plant species containing bioactive materials for functional foods or medicines. The antioxidative activity was higher in Cytomium fortunei(41.9%) and Rumohra standishii(34.1%) than in leaves of Thea sinensis(30.9%), a small tree for antioxidative beverage. Inhibitory activities of ACE and APN were relatively high in Cytomium fortunei as 26.7% and 28.2% respectively. $\alpha$-Amylase inhibitory activity was higher than 50% in 10 species. Particularly, Cytomium fortunei(87.4%) and Dryopteris erythrosora(71.6%) showed the inhibitory activities higher than those of other form plants. Of 25 fern plants investigated here, Cytomium fortunei showed not only the highest antioxidative activity but also the highest inhibitory activity of ACE, APN and $\alpha$-amylase. It suggests that Cytomium fortunei could be potentially used as a resource of bioactive materials for fuctional foods or medicines.