• Preventive Nutrition and Food Science
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• v.2 no.4
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• pp.285-290
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• 1997

Previously, a 50% aqueous methanol extract of Galla rhois was shown to be the most potent tyrosinase inhibition activity with an {TEX}$IC_{50}${/TEX}(the concentration causing 50% inhibition of tyrosinase activity) of 0.2mg/ml of 205 crude drug extracts. To isolate tyrosinase inhibitors, the methanol extract was evaporated to a small volume in vacuo, and then partitioned stepwise with benzene and ethyl acetate(EtOAc). the EtOAc fraction was solubilized in 10% MeOH solution, and then fractionated successively by Diaion HP-20 and Sephadex LH-20 column chromatography, and preparative HPLC. Three phenolic compounds were isolated, and characterized as gallic acid(GA), methyl gallate(MG) and 1,2,3,4,6-penta-O-galloyl-$\beta$-D-glucose(PGG) by UV, IR, {TEX}${1}^H${/TEX}-&{TEX}${13}^C${/TEX}-NMR, and FAB-MS spectroscopy, PGG({TEX}$IC_{50}${/TEX}=50$\mu\textrm{g}$/ml) showed a considerable inhibitory effect against mushroom tyrosinase, while GA({TEX}$IC_{50}${/TEX}=1.6mg/ml) and MG({TEX}$IC_{50}${/TEX}=234$\mu\textrm{g}$/ml) did not show an appreciable effect. Meanwhile, MG inhibited greatly melanogenesis in a murine melanocyte cell line, Mel-Ab. MG and PGG showed typical noncompetitive inhibition patterns against mushroom tyrosinase. These results suggest that PGG and MG may be potentially useful as either anti-browning or anti-melanogenic agents in foods and cosmetics.

• BMB Reports
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• v.32 no.3
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• pp.254-258
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• 1999

The NADPH-dependent succinic semialdehyde reductase is one of the key enzymes in the brain GABA shunt, and it catalyzes the formation of the neuromodulator $\gamma$-hydroxybutyrate from succinic semi aldehyde. This enzyme was inactivated by diethylpyrocarbonate (DEP) with the second-order rate constant of $1.1{\times}10^3\;M^{-1}min^{-1}$ at pH 7.0, $25^{\circ}C$, showing a concomitant increase in absorbance at 242 nm due to the formation of N-carbethoxyhistidyl derivatives. Complete inactivation of succinic semialdehyde reductase required the modification of five histidyl residues per molecule of enzyme. However, only one residue was calculated to be essential for enzyme activity by a statistical analysis of the residual enzyme activity. The inactivation of the enzyme by DEP was prevented by preincubation of the enzyme with the coenzyme NADPH but not with the substrate succinic semialdehyde. These results suggest that an essential histidyl residue involved in the catalytic activity is located at or near the coenzyme binding site of the brain succinic semialdehyde reductase.

• BMB Reports
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• v.32 no.3
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• pp.239-246
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• 1999

A tripeptidase (PepT) was purified to homogeneity from Bacillus subtilis through four sequential chromatographies including DEAE-Sepharose ion exchange, hydroxylapatite, mono-Q FPLC ion exchange, and Superose-12 FPLC gel filtration. The apparent molecular mass of the enzyme was 49,200 Da and 51,400 Da as determined by sodium dodecylsulfatepolyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration chromatography, respectively, and the enzyme exists in a monomeric form. The physicochemical properties of the enzyme were as follows: optimum pH at 7.5, optimum temperature at $60^{\circ}C$, and pI at 4.9. The $K_m$ and $V_{max}$ values of the enzyme were 4.3 mM and 2.5 mmol/min/mg, respectively, with MetAla-Ser as substrate. The B. subtilis PepT requires $Co^{2+}$ ion(s) for activation, while it is inactivated by EOTA and 1,10-phenanthroline, suggesting that it is a metalloprotein. The enzyme was not inhibited by any of serine protease, aspartic protease, or leucine aminopeptidase inhibitors. The enzyme showed comparable activities towards four different substrates including Met-Ala-Ser, Leu-Gly-Gly, Leu-Ser-Phe, and Leu-Leu-Tyr. The amino terminal sequence of PepT determined by Edman degradation was found to be MKEEIIERFTTYVXV and turned out to be identical to that of PepT deduced from a cloned B. subtilis pepT.

• Journal of computational fluids engineering
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• v.21 no.2
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• pp.70-80
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• 2016

The comparison of two commercial codes(FLUENT and STAR-CCM+) and an open-source code(OpenFOAM) are carried out for the aerodynamic analysis of flight vehicles at low speeds. Tailless blended-wing-body UCAV, main wing and propeller of HALE UAV(EAV-3) are chosen as geometries for the investigation. Using the same mesh, incompressible flow simulations are carried out and the results from three different codes are compared. In the linear region, the maximum difference of lift and drag coefficients of UCAV are found to be less than 2% and 5 counts, respectively and shows good agreement with wind tunnel test data. In a stall region, however, the reliability of RANS simulation is found to become poor and the uncertainty according to code also increases. The effect of turbulence models and meshes generated from different tools are also examined. The transition model yields better results in terms of drag which are much closer to the test data. The pitching moment is confirmed to be sensitive to the existence and the location of transition. For the case of EAV-3 wing, the difference of results with ${\kappa}-{\omega}$ SST model is increased when Reynolds number becomes low. The results for the propeller show good agreement within 1% difference of thrust. The reliability and uncertainty of three codes is found to be reasonable for the purpose of engineering use. However, the physical validity and reliability of results seem to be carefully examined when ${\kappa}-{\omega}$ SST model is used for aerodynamic simulation at low speeds or low Reynolds number conditions.

• Journal of computational fluids engineering
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• v.20 no.3
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• pp.79-86
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• 2015

A blood pump is an important part of a cardiac assist device. Since the shear rate in blood is known to be a primary factor on hemolysis generation, it has been very important to evaluate hemolysis inside blood pumps for understanding performance and reliability of cardiac assist devices. In this study, hemolysis generation inside blood pumps is analyzed using CFD with power-law based models for the blood damage index(BDI), in order to overcome difficulties in measuring hemolysis by experiment. The BDI values in blood pumps can be evaluated using Lagrangian or Eulerian approaches. In this study, several Lagrangian and Eulerian approaches are compared to estimate the efficiency of the numerical methods in a practice sense. It is found that the Eulerian approaches are advantageous in terms of the efficiency and robustness. Two different Eulerian approaches are used to evaluate the BDI values of a few commercial blood pumps. For the conditions of extracorporeal membrane oxygenator(ECMO) and ventricular assist device(VAD), local generation of hemolysis is analyzed using divided regions of blood pumps, in order to investigate the effects of the pump geometry.

• Economic and Environmental Geology
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• v.12 no.4
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• pp.207-221
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• 1979

The studied area occupies the southern part of Haenam peninsula located in the southwestern corner of Korea. The stratigraphic sequences of the area are grouped into following three units in ascending order. (1) Late Cretaceous sedimentary rocks of Uhangri Formation which consist of the alternative beds of black shales and tuffaceous sediments, Hwangsan acidic fine grained tuffs and Jindo rhyolite flows. (2) Late Cretaceous biotite granite and acidic porphyries which intruded the Late Cretaceous sedimentary rocks. (3) Tertiary(?) pitchstone. The study purposes to delineate any of geochemical aspects on the deposition of the sequences, the average amounts of organic materials and the effect to the maturation of hydrocarbonization which has been occured by the intrusives. Sixty nine black shale samples were collected from Uhangri Formation in the northern and southern coasts of the peninsula. Organic carbons, total extracted organic matters and hydrocarbons were mainly determined by the Soxhlet extraction method, together with C-H-N elemental analyses. Based on the field and laboratory studies, the following interpretations have been obtained. (1) The paleohydrostatic condition of the sedimentation which took place was relatively calm and stable to delineate a lacustrine environment. (2) The amounts of organic material were more or less constant throughout the period of the deposition of the sediments. (3) The degree of hydrocarbonization of the Uhangri Formation in the northern coast was taken place higher than that in the southern coast due to the differences of thermal effect by the biotite granite which is assumed to be as a heat source in the area. Among the northern coast, some black shales in Uhangri and Mogsam areas which had been under the most moderate temperature environment snow symptomatic oily material, whereas, those in Sinseongri area do not, which were presumably to be intensive thermal alteration by the later acidic porphyries.

• Journal of Animal Science and Technology
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• v.47 no.3
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• pp.355-362
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• 2005

This study was carried out to obtain basic information on variety selection for the utilization of whole crop rices(WCR) at National Institute of Crop Science, RDA, in 2004. Fifteen varieties and elite line were evaluated on feed value such as dry matter yield(DMY), crude protein( CP), acid detergent fiber(ADF), neutral detergent fiber(NDF) and total digestible nutrients(TDN). The dry matter yields were ranged from 13.23 to 17.83 ton per ha, the highest yielding varieties were Sobibyeo(l6.98ton / ha) in Japonica type, SR22060 (17.83 ton / ha) in New plant type, Hangangchalbyeo(I7.66 ton / ha) in Tongil type. Suweon 468 showed the highest value in the RFV and TDN content among the varieties, and Suweon 468, Suweon 498, Suweon 490 and SR22058 were chosen to have the high feed values through cluster analysis. The dry weight(grain) was found to be positively related with percent of the ripened grain, 1,000 grain weight and CPo TDN content was found to be positively related with CP, but negatively related with NDF and ADF. RFV was found to be negatively related with plant height, NDF and ADF. The promising rice varieties for WCR were Suweon 468, Suweon 498, Suweon 490 and SR22058 on the basis of CP, TDN and DMY.

• Journal of Animal Science and Technology
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• v.53 no.3
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• pp.211-222
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• 2011

The present review was aimed to assess the feasibility of increasing the slaughter weight (SW) of finishing pigs. Growth performance, including ADG, ADFI and gain:feed, does not change significantly with increasing SW between 110 and $135{\pm}5kg$ in lean-genotype pigs, whereas in non-lean pigs, ADG and gain:feed decrease with increasing SW within the similar range of BW. Backfat thickness (BFT) and marbling of the carcass, which are greater in barrows than in gilts, increase with the increase of SW. The SW could be increased by using a low-energy diet and thereby reducing the rate of fat deposition per weight gain. The yield of the belly increases with the increase of SW, which may be economically significant in Korea. However, yields of some other primal cuts do not change so much as to affect the carcass value. The redness and fat content of the muscle increase slightly with the increase of SW whereas moisture content is minimally influenced by SW. Muscular protein content rarely changes, but sometimes increases slightly, with increasing SW. Other physicochemical characteristics, including lightness, pH, drip loss, and cooking loss of the muscle, are barely influenced by SW. Marbling of fresh loin and ham increases with increasing SW. Sensory characteristics of fresh loin, ham, and belly, including color, aroma, off-flavor, drip, and acceptability, are not influenced significantly by SW. The eating quality of cooked pork also has almost no relation to SW. In conclusion, it is thought that the current SW for moderately lean barrows and gilts can be raised up to 125 and 135 kg, respectively, with BFT at these weights predicted to be approximately 24 mm near the last rib, without compromising the meat quality.

• Mass Spectrometry Letters
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• v.3 no.1
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• pp.21-24
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• 2012

$5{\alpha}$-Dihydrotestosterone (DHT) is the primary active metabolite of testosterone, catalyzed by $5{\alpha}$-reductase ($5{\alpha}R$) in the skin, prostate, and liver. In this study, the $5{\alpha}R$ activity in rat liver S9 fraction in the presence of a NADPH-generating system was evaluated and compared by gas chromatography-mass spectrometry (GC-MS)-based in vitro assays. Testosterone and a $5{\alpha}R$ inhibitor, finasteride, were added to the S9 fractions and incubated at $37^{\circ}C$ for 1 h. Both testosterone and DHT were quantitatively measured and compared with two different GC-MS-based steroid profiling techniques. DHT was not detected by conventional GC-MS analysis in the absence of finasteride when the concentration of testosterone in the S9 fraction was less than $0.2{\mu}M$, whereas the isotope-dilution GC-MS (GC-IDMS) system was able to evaluate the $5{\alpha}R$ activity. Because the S9 fraction contains more reactive enzymes and is easier to collect from tissues compared with a microsomal solution, the combination of the S9 fraction and GC-IDMS technique may be a promising assay for evaluating the $5{\alpha}R$ activity in large-scale clinical studies.

• Proceedings of the KAIS Fall Conference
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• 2010.11a
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• pp.482-482
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• 2010

하수처리장에서 발생하는 유기성 슬러지는 대부분 해양투기에 의해 처분되고 나머지는 매립, 소각, 퇴비화 등으로 처분된다. 그러나 런던협약 '96 의정서' 발효에 의해 2012년부터 해양투기가 금지되고, 매립장 및 소각장의 신규건설은 님비(NIMBY) 현상에 의해 제한받기 때문에 효과적인 슬러지 처분 및 가용화 방법이 요구되고 있다. 현재 초음파[1]나 열처리[2], 오존[3,4], 미생물 처리[5,6] 등 물리, 화학, 생물학적 처리방안이 연구되고 있으나 이러한 방법들은 에너지 과소비, 2차 오염물질 발생에 따른 처리비용 증가 등의 단점을 가지고 있다. 따라서 본 연구에서는 기존의 연구 방법을 보안하고자 전기분해를 활용하여 슬러지 가용화를 시도함으로써 슬러지 발생을 저감시킬 수 있는 방법을 연구하였다. 본 실험에서는 전기분해를 위해 제작된 불용성 전극은 Titanium에 Iridium을 코팅하여 제작하였고, 최대 20V까지 전압을 고정시키고 시간에 따라 변화되는 전류와 전기전도도, pH 값을 관찰하였다. 실험에 사용된 활성슬러지는 3개월간 합성폐수로 순응화 시킨 후에 시료로 사용하였다. 전기분해에 의해 처리된 활성슬러지의 여액을 분석한 결과 SCOD, TN, TP 농도가 각각 510%, 9%, 106% 증가하였다. 이는 전기분해에 의해 미생물의 세포벽이 파괴되어 세포 내 물질들이 세포 외부로 용출되어 미생물들의 이용이 가능한 상태로 되었음을 알 수 있었다. 이는 국내 하 폐수의 낮은 C/N비 때문에 무산소조에 메탄올 같은 외부 탄소원을 공급하는 대신에 별도의 탄소원 공급 없이 가용화 된 슬러지를 반송시킴으로써 슬러지 저감에 따른 폐기 비용과 운전비용의 절감을 기대할 수 있어, 근본적인 슬러지 발생을 저감시킬 수 있는 해결책이라 할 수 있다.