• Applied Chemistry for Engineering
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• v.16 no.2
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• pp.231-237
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• 2005

The sizes and structure of micelles and vesicles formed in ammonium dodecyl sulfate (ADS)/octadecyl trimethyl ammonium chloride (OTAC) mixed aqueous solutions were analyzed by small-angle neutron scattering. In micellar regions of pure ADS and OTAC aqueous solution, the spherical micelles were formed at given concentrations and their sizes were 40 and $61{\AA}$, respectively. The structure transition of pure micelles occurred above 300 mM due to the constancy of the intermicellar distance above 250 mM. The coexisting region of mixed micelles and vesicles in phase diagram of mixed system was also assured. It was investigated that vesicle formed spontaneously took a bilayer structure. The lamellar thickness of vesicles decreased with increasing concentration of vesicle samples. However, the size could not be determined for mixed micelle and vesicle above 100 nm due to limitation of low q ranges. Finally, The 9 mM solution of ADS mole fraction 0.9 (${\alpha}$=0.9) showed bilayer structure compared to phase diagram classified into mixed micelle.

• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.734-741
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• 1998

Electrode characteristics were studied in the interface between sample solutions and $K^+$ ion selective PVC membrane electrodes containing neutral carriers, dibenzo-18-crown-6(D18Cr6) and valinomycin(Val). The effect of doping of base electrolytes, the chemical structure and the content of carrier, variation of plasticizer, membrane thickness, and concentration variation of sample solution on the response characteristics of electrode such as the measured Nernstian slope, the detection limit, the linear response range, and potentiometric selectivity coefficients, were studied. In order to synthesize the membrane D18Cr6 and Val as neutral carriers were used, and complex between the carrier and $K^+$ ions were used as active materials. PVC membrane electrodes were made of plasticizers (DBP, DOS, and DBS), the base electrolyte[potassium tetraphenylborate(KTPB)], and solvent(THF). The chemical structure of carrier D18Cr6 was best for electrode and ideal electrode characteristics were appeared especially in case of doping of TPB. The optimum carrier content was about 3.23 wt % in case of D18Cr6 and Val. DBP was best as a plasticizer. As membrane thickness decreased the electrode characteristics was improved. But its characteristics were lowered below the optimum membrane thickness because of the elution of carrier, deterioration of membrane strength, etc. In the case of D18Cr6, the selectivity coefficients by the mixed solution method for the $K^+$ ion were in the order of $NH_4{^+}>Ca^{2+}>Mg^{2+}>Na^+$.

• Korean Journal of Ecology and Environment
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• v.36 no.2 s.103
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• pp.108-116
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• 2003

To investigate bacteria with algal Iytic activities against Anabaena cylindrica when water blooming occurs and to study enzyme profiles of alga-Iytic bacteria, various bacterial strains were isolated from surface waters and sediments in eutrophic lakes or reservoirs in Korea. Abacterial strain AK-07 was characterized and identified as Acinetobacter johnsonii based on its16S rDNA base sequence. When AK-07 was co-cultivated with A. cylindrica, bacterial cells propagated to $8\;{\times}\;10^8$ cfu $ml^{-1}$ and Iyses algal cells. However, culture filtrates of AK-07 did not exhibit algal Iytic activities. That suggesting the enzymes on the surfaces of the bacterium might be effective algal Iytic agents to cause Iyses of cells. Acinetobacter johnsonii AK-07 exhibited high degradation activities against A. cylindrica, and formed alginase, caseinase, lipase, fucodian hydrolase, and laminarinase. Moreover, glycosidases for example ${\beta}$-galatosidase, ${\beta}$-glucosidase, ${\beta}$-glucosaminidase, and ${\beta}$-xylosidase, which hydrolyzed ${\beta}$-0-glycosidic bonds, were found in cell-free extracts of A. johnsonii AK-07. Other glycosidase such as ${\alpha}$-galctosidases, ${\alpha}$-N-Ac-galctosidases, ${\alpha}$-mannosidases, and ${\alpha}$- L-fuco-sidases, which cleavage ${\alpha}$-0-glycosidic bondsare not detected. In the results, enzyme systemsof A. johnsonii AK-07 were very complex to do-grade cell walls of cyanobacteria. The polysaccharides or peptidoglycans of A. cylindrica maybe hydrolyzed and metabolized to a range of easily utilizable monosaccharides or other low molecular weight organic substances by strain AK-07 of A. johnsonii.

• Journal of Life Science
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• v.15 no.6 s.73
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• pp.979-986
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• 2005

Lead (Pb) exposure during development can produce neurological deficits. In this study, the effect of Pb exposure during neonatal development via lactation on anxiety of brain function was investigated. Long-Evans strain rats were raised through two generations. At the birth of the second generation, the dams were subdivided into two groups and supplied drinking water containing either $0.2\%$ Pb (Pb-treated group) or sodium (Na, Control group) acetate until weaning. Rats were sacrificed at 3 (weaning) and 11 weeks (maturity) for brain Pb and fatty acid analysis. Motor activity and elevated plus maze tests were initiated at 9 weeks. The brains in the Pb-treated group at weaning and maturity contained 1486$\pm$98 and $270{\pm}46$ ng Pb/g, respectively The control group showed the background level of Pb ($3.7{\pm}1.0_{ng}$ Pb/g) in both ages. The alterations in brain fatty acid composition induced by Pb exposure were more evident in 3 wks old than 11 wks old. For example, in 3 wks old, the percentages of $18:2_{n-6}$, $20:2_{n-6}$ and $18:2_{n-6}$ were decreased in the Pb-treated group with an increase in $20:4_{n-6}$ In motor activity test, there was a tendency of hyperactivity in the Pb-treated group compared with the control group but the difference was not significant. In elevated plus maze test, the Pb-treated group showed fewer numbers of visits to the open arms (P < 0.05), indicating that Pb exposure may lead to anxiogenic effect.

• Korean Journal of Food Science and Technology
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• v.46 no.5
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• pp.616-621
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• 2014

This study was conducted to investigate the detoxification effect of extract from soy-sprout grown using high concentrated oxygen water extract (SE) against alcohol-induced hangover in male Sprague-Dawley (SD) rats. The rats were orally administered with different concentrations of SE beverage [26, 260 and 2,000 mg/kg body weight (b.w.)] and, after 30 min, with alcohol at a dose of 3 g/kg b.w. After 1 and 3 h of alcohol administration, blood was collected from the retro-orbital plexus, while after 5 h, blood was collected from the heart. In the 2,000 mg/kg b.w. SE group, the concentration of blood alcohol was significantly reduced after 1-5 h of alcohol loading as compared with that in the other groups. In addition, the blood acetaldehyde concentration was reduced by SE (2,000 mg/kg b.w.). These results suggest that SE beverage can alleviate alcohol hangover symptoms by stimulating the activities related to hepatic alcohol-metabolizing enzymes.

• Korean Journal of Clinical Laboratory Science
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• v.51 no.4
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• pp.514-520
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• 2019

This study investigated the improved lipid metabolism effect of 3T3-L1 cells induced by adipocytes using the dichloromethane (DCM) fraction in the organic solvent extract of Wassong (Orostachys japonicus). To confirm the cell cytotoxicity, each of 6 fractions of organic solvent extracts (EtOH, Hexane, DCM, EtOAc, BuOH, and H₂O) was examined using MTS assay. As a result, it was confirmed that the DCM extract was stable over the whole range of concentrations, and a DCM fraction was used to confirm the improved lipid metabolism effect. Lipid excretion was measured to confirm the change of lipid metabolism. 3T3-L1 cells induced by adipocytes were treated with DCM extract and stained with oil-red O to evaluate lipid accumulation. As a result, it was confirmed that the lipid efflux was significantly improved. In order to confirm the mechanism of lipid efflux, the mRNA expressions of ABCA1 and ABCG1, which are lipid transport proteins, were confirmed by real-time PCR. Therefore, the present study confirmed that the DCM extract from Orostachys japonicus has the effect of improving the lipid metabolism on 3T3-L1 adipocytes. In addition, the results of this study will be used as the basis for the development of functional foods using Orostachys japonicus and also for conducting research on the detailed mechanisms.

• Food Science of Animal Resources
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• v.30 no.2
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• pp.286-290
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• 2010

Angiotensin-converting enzyme (ACE) inhibitory activity and production optimization of ovotransferrin hydrolysates were studied. Ovotransferrin was hydrolyzed by several enzymes (protamex, alcalase, trypsin, pepsin, neutrase, and flavorzyme) and acid (0.03 N HCl). Ovotransferrin hydrolysate reduced ACE activity by 60.2%, 55.8%, and 42.6% when treated with trypsin, acid, and pepsin, respectively. Trypsin was selected for production of peptide having maximum AC inhibitory effect, which was greatest with 7 h hydrolysis. Central composite design determined that optimum composition of ACE inhibitory substances using substrate concentration of 20-35%, temperature of $35-55^{\circ}C$, and pH of 6.0-8.0. The optimum composition was 1% trypsin, substrate concentration of 26.32%, $51.29^{\circ}C$, and pH 6.32. Under this conditions, a maximum ACE inhibitory effect of 69.1% was evident, similar to the predicted value.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.119-119
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• 2009

인버터 DC 저항용접의 적용성 증대 : 인버터 DC 저항용접 공법이 SPOT, PROJECTON, SEAM, BUTT 등의 공정에 다양하게 적용되어 저항용접 현장에서 고효율, 친환경적 용접 환경을 만드는데 일조 하고 있다. 특히 자동차의 경량화, 충돌내성 증대, 진동 및 내구성 증대, 공간활용 극대화, 새로운 Design 개념 적용 등의 산업전반에 걸쳐 나타나는 신 Trends로 고 장력 철재의 적용 범위가 확대되고 HSS(High Strength Steel), EHSS(Extra High Strength Steel), UHSS (Ultra High strength Steel ; Hot - Formed Steel )등 다양한 철판의 SPOT 저항용접이 필요하게 되었다. 기존의 AC 단상용접의 전력 특성 상 통전 중 무 통전 시간 과 높은 PEAK 전력, 단상 대 전력 소모로 인한 전력 DROP 등의 문제로 인하여 신소재의 용접 시 매우 많은 Spatter가 발생하고, 높은 용접품질의 확보가 어려워 지므로 이를 대체하기 위한 공법으로 MFDC ( 인버터 DC 저항용접공법 )이 적용되고 있다. 인버터 DC 저항용접의 적응제어 : MFDC라는 높은 효율의 용접 전력원이 확보 됨에도 불구하고 용접현장에서는 원 자재, 도금 등의 품질 산포, 프레스 물의 가공산포, 공기압 산포, 전극 과열 및 마모 등의 요인에 의하여 저항용접 산포가 발생하고 있다. 이는 인위적인 조작이 어렵고 불규칙적이며, 어디서나 산재하고 있는 문제이다. 이를 용접전력 제어 법으로 개선하여 일정한 용접성을 확보하기 위한 노력이 적응제어 기법이다. 정 전류, 정 전력 제어는 정량 제어로 용접 물을 비롯한 용접부의 변화와는 관계없이 설정된 일정량의 전력을 공급하기만 하는데 반하여 적응제어는 적절한 용접 작업 시의 용접 물의 상태, 전극의 가압, 표면 상태 등에 따른 변화 페턴을 기억하고 이후 진행되는 용접에 대하여 정상 페턴과의 차이를 감지 이를 보상하므로 고품질의 용접성을 보장하는 제어기법이다. 따라서 다양한 용접 산포 유발 요인에 의해 용접부의 변화가 발생한다 하여도 그 변화를 감지 하고 적절한 용접전력을 공급한다면 고품질의 용접성을 확보하는데 유용한 공법이 될 수 있다. 인버터 DC 저항용접의 SPC 관리 : SPOT 용접 시 획득할 수 있는 다양한 파라메터에 대하여 모니터링 하고 이 자료를 data 화 하여 품질 관리에 응용하게 되면 양산라인에서 반복적으로 발생되는 문제점을 확인 할 수 있고 이를 통계적 방법으로 추적 개선해 나간다면 용접 불량 감소 및 생산성 향상에 도움이 되며 작업자의 공정 능력 향상 및 기업의 기술축적에도 높은 기여를 할 수 있을 것이다. 용접 적응제어와 다양한 파라메터 모니터링이 한 system에서 이루어 질 때 높은 용접성 확보와 불량률 감소, 원가절감, 생산성 향상 등의 효과가 극대화 될 것이다.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.564-567
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• 2009

"Boseog" is a new japonica rice cultivar developed from the three way cross of Kinuhikari//HR19621AC6/Sobibyeo and registered by the rice breeding team of Department of Rice and Winter Cereal Crop, NICS, RDA in 2008. This cultivar has about 110 days of growth duration from transplanting to harvesting in northern plain, northern and southern mid-mountainous area of Korea. This cultivar is about 72 cm in culm length and tolerant to lodging. In the reaction to biotic and abiotic stresses, it shows resistance to leaf blast, but susceptibility to bacterial blight, virus diseases and insect pests. The milled rice of "Boseog" exhibits translucent, relatively clear non-glutinous endosperm and midium short grain. It has similar amylose content(18.0%), lower protein content(6.3%), and similar palatability of cooked rice compared to Odaebyeo. The milled rice yield of this variety is about 5.03 MT/ha in local adaptability test. "Boseog" would be adaptable for ordinary transplanting in northern plain, mid-mountainous and southern mountainous area of Korea.

• Bulletin of the Korean Chemical Society
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• v.21 no.11
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• pp.1125-1132
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• 2000

The pH effect of the precursor solution on the preparation of $LiCoO_2$ by a solution phase reaction containing malonic acid was carried out. Layered $LiCoO_2$ powders were obtained with the precursors prepared at the different pHs (4, 7, and 9) and heat-treated at $700^{\circ}C(LiCoO_2-700)$ or $850^{\circ}C(LiCoO_2-850)$ in air. pHs of the media for precursor synthesis affects the charge/discharge and electrochemical properties of the $LiCoO_2electrodes.$ Upon irrespective of pH of the precursor media, X-ray diffraction spectra recorded for $LiCoO_2-850$ powder showed higher peak intensity ratio of I(003)/I(104) than that of $LiCoO_2-700$, since the better crystallization of the former crystallized better. However, $LiCoO_2$ synthesized at pH 4 displayed an abnormal higher intensity ratio of I(003)/I(104) than those synthesized at pH 7 and 9. The surface morphology of the $LiCoO_2-850$ powders was rougher and more irregular than that of $LiCoO_2-700$ made from the precursor synthesized at pH 7 and 9. The $LiCoO_2electrodes$ prepared with the precursors synthesized at pH 7 and 9 showed a better electrochemical and charge/discharge characteristics. From the AC impedance spectroscopic experiments for the electrode made from the precursor prepared in pH 7, the chemical diffusivity of Li ions (DLi+) in $Li0.58CoO_2determined$ was 2.7 ${\times}$10-8 $cm^2s-1$. A cell composed of the $LiCoO_2-700$ cathode prepared in pH 7 with Lithium metal anode reveals an initial discharge specific capacity of 119.8 mAhg-1 at a current density of 10.0 mAg-1 between 3.5 V and 4.3 V. The full-cell composed with $LiCoO_2-700$ cathode prepared in pH 7 and the Mesocarbon Pitch-based Carbon Fiber (MPCF) anode separated by a Cellgard 2400 membrane showed a good cycleability. In addition, it was operated over 100 charge/discharge cycles and displayed an average reversible capacity of nearly 130 mAhg-1.