• 한국식품영양과학회지
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• 제26권3호
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• pp.494-500
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• 1997

This study was conducted to investigate the effect of acorn extracts on the antioxidative enzyme system. Male Sprague-Dawley rats(110$\pm$10g) were fed on containing normal and high fat diets. They were orally administrated (0.02g/100g B.W) of acorn ethylacetate-extract and water-extract at the same time once a day, respectively. Net weight gain and feed efficiency ratio were increased in high fat diet groups and decreased by acorn extracts administration. The effect of acorn extracts on hepatic glutathione peroxidase(GSH-Px), glutathione S-transferase(GST) and catalase activities did not show significancy in normal fat diet groups. GST and catalase activities and lipid peroxidation content(LPO) were significantly increased in high fat diet groups and this increment were decreased by acorn extracts administration. However GSH-Px activity and GSH content were decreased in high fat diet groups but increased by acorn extracts administration. The activities of lactate dehydrogenase(LDH), alkaline phosphatase(ALP) and aminotransferase in serum were significantly increased in high fat diet group but these increment reduced in acorn extracts administration groups. These results indicate that acorn extracts could improve the liver function and prevent the metabolic diseases by hyperlipidemia.

• Geomechanics and Engineering
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• 제20권2호
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• pp.165-174
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• 2020

The enzyme-induced carbonate precipitation (EICP) method has been investigated to improve the hydro-mechanical properties of natural soil deposits. This study was conducted to explore the stiffness evolution during various stress scenarios. First, the optimal concentration of urea, CaCl₂, and urease for the maximum efficiency of calcite precipitation was identified. The results show that the optimal recipe is 0.5 g/L and 0.9 g/L of urease for 0.5 M CaCl₂ and 1 M CaCl₂ solutions with a urea-CaCl₂ molar ratio of 1.5. The shear stiffness of EICP-treated sands remains constant up to debonding stresses, and further loading induces the reduction of S-wave velocity. It was also found that the debonding stress at which stiffness loss occurs depends on the void ratio, not on cementation solution. Repeated loading-unloading deteriorates the bonding quality, thereby reducing the debonding stress. Scanning electron microscopy and X-ray images reveal that higher concentrations of CaCl₂ solution facilitate heterogeneous nucleation to form larger CaCO₃ nodules and 11-12 % of CaCO₃ forms at the interparticle contact as the main contributor to the evolution of shear stiffness.

• 대한수의학회지
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• 제33권4호
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• pp.611-615
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• 1993

젖소에서 progesterone과 testosterone의 측정을 위하여 solid phase 효소면역분석법(酵素免疫分析法)를 개발하였다. 1차 항체로서 $11{\alpha}$-hemisuccinate-progesterone bovine serum albumin과 4-androsten-$17\;{\beta}$-ol-3-one-carboxymethyloxime bovine serum albumin에 대한 토끼 혈청(血淸)을 각각 항혈청(抗血淸)으로 사용하였고, 2차 항체로서 면약 IgG를 사용하였다. Conjugates로서는 각각 progesterone-$11\;{\alpha}$-hydroxy-hemisuccinate-horseradish peroxidase와 4-androsten-$17\;{\beta}$-ol-3-hemisuccinate-horseradish peroxidase를 사용하였다. Progesterone과 testosterone에 대한 최저측정치(最低測定値)는 각각 6.7 pg/well과 1.0 pg/well이었다.

• Journal of Nutrition and Health
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• 제37권3호
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• pp.169-175
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• 2004

This study was performed to investigate the effect of acorn supplementation on the lipid profile and redox antioxidant enzyme activities in obese rat. Obesity in the rats was induced by feeding diet contained 10％ lard and 0.5％ cholesterol for 4 week. After 4 weeks, rats were divided into the following 5 groups; high fat diet (Control), high fat diet plus 10％ Acorn powder (APlO％), high fat diet plus 20％ Acorn powder (AP20％), high fat diet plus 0.2％ Acorn extract (AE0.2％), high fat diet plus 0.5％ Acorn extract (AE0.5％). Total food intake and food efficiency ratio (FER) was not significantly different by acorn powder and extract supplementation. But, body weight was decreased by 20％ acorn powder. Acorn powder and extract supplementation for 4 weeks tend to decrease total cholesterol and triglyceride level on the serum and hepatic tissue. There was no significant difference in hepatic glutathione (GSH) content among all the groups. The hepatic GST activity in acorn supplemented groups was lower than that of control. Glutathione peroxidase and catalase activities were higher in acorn supplemented groups than that of control. Hepatic TBARS levels of experimental groups were also significantly lower than that of control group. Our finding suggest that acorn powders and extract might have potential role for improving lipid profiles and antioxidant enzyme activities in obese rats.

• Journal of Microbiology and Biotechnology
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• 제31권5호
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• pp.740-746
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• 2021

Efficient cellulolytic enzyme production is important for the development of lignocellulose-degrading enzyme mixtures. However, purification of cellulases from their native hosts is time- and labor-consuming. In this study, a constitutive expression system was developed in Penicillium oxalicum for the secreted production of proteins. Using a constitutive polyubiquitin gene promoter and cultivating with glucose as the sole carbon source, nine cellulolytic enzymes of different origins with relatively high purity were produced within 48 h. When supplemented to a commercial cellulase preparation, cellobiohydrolase I from P. funiculosum and cellobiohydrolase II from Talaromyces verruculosus showed remarkable enhancing effects on the hydrolysis of steam-exploded corn stover. Additionally, a synergistic effect was observed for these two cellobiohydrolases during the hydrolysis. Taken together, the constitutive expression system provides a convenient tool for the production of cellulolytic enzymes, which is expected to be useful in the development of highly efficient lignocellulose-degrading enzyme mixtures.

• 한국수소및신에너지학회논문집
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• 제33권5호
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• pp.507-514
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• 2022

There is growing interest in sustainable energy sources that can reduce fossil fuel dependence and environmental pollution while meeting rapidly growing energy demands. Hydrogen have been investigated as one of the ideal alternative energies because it has relatively high efficiency without emitting pollutants. The light-sensitized enzymatic (LSE) system, which uses hydrogenase-enzymes, is one of the methods towards economically feasible system configurations that enhance the rate of hydrogen generation. Hydrogenase is an enzyme that catalyzes a reversible reaction that oxidizes molecular hydrogen or produces molecular hydrogen from protons and electrons. In this paper, utilization of [NiFe]-hydrogenase (from Pyrococcus furiosus) in photoelectrochemical hydrogen production system such as handling, immobilization, physicochemical and electrochemical analysis, process parameters, etc. was introduced.

• 상하수도학회지
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• 제20권1호
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• pp.128-137
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• 2006

This study aims at developing the practical technology in the treatment of box-mill wastewater using the aerobic co-metabolism principle. The conventional activated sludge method exhibited the removal efficiency of $TBOD_5$ and $TCOD_{Mn}$ as 30~50% and 40~50%, respectively. Color was rather increased by 30~130% because the conventional treatment under the aerobic condition did not induce the conversion of molecular structure of dyeing agents. Meanwhile, when the aerobic co-metabolism principle was applied to the same wastewater, the removal efficiency of $TBOD_5$ and $TCOD_{Mn}$ were obtained as 92~97% and 90~94%, respectively. In particular, color was significantly reduced down to 65~85%. The enhancement of treatment efficiency was ascribed to occur not only that the non-degradables were converted to the second substrates, but also that the enzyme activity was increased as MLVSS was kept 3000mg/l or more with the first substrates injected.

• 펄프종이기술
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• 제32권1호
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• pp.48-56
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• 2000

The objective of this study was to investigate the enzymatic deinking technology. Office recycled papers such as computer printed out(CPO) and white ledger(WL) were used in the evaluation of four different deinking conditions ; alkaline deinking , neutral deinking and enzymatic deinking at alkaline and neutral pH. Filltering pads were prepared after flotation deinking to measure brighteness gain and ink removal efficiency. Three different surfactants were also used in the evaluation of deinking efficiency including surface chemical properties by measuring foam height and stability, surface tension and cloud point of views. The results indicated that the neutral deinking method with enzyme and surfactant addition showed highest deinking efficiency of office recycled papers.

• Asian-Australasian Journal of Animal Sciences
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• 제19권9호
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• pp.1354-1360
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• 2006

Maize-soybean meal diets with 0, 100, 200 and 300 g/kg double zero rapeseed meal ('00' RSM) with and without an enzyme mixture (xylanase, pectinase, cellulase) at a level of 1.6 g/kg were evaluated with 624 day-old broiler chicks for 5 weeks. The birds were randomly allocated to eight dietary treatments with three replicates of 26 birds each. Average daily gain (ADG) and feed intake (FI) were recorded weekly and ileal viscosity, organ weights, serum enzyme activity, hormonal profile and hematological parameters were measured at the end of week 5. Average daily gain during the weekly periods was significantly influenced by the dietary level of '00'RSM (p<0.01). Inclusion of '00' RSM improved the ADG up to day 28 with the increased level; beyond that time no improvement was recorded when compared to control groups. However, ADG from 1-35 days was significantly different between 300 g/kg inclusion level of '00' RSM and the control diet. Inconsistent decline in feed intake and feed conversion ratio was observed up to day 21 and the trend was reversed thereafter. The proportion of '00' RSM in the diet had a significant ($p{\leq}0.05$) influence on thyroid weight but had no effect on the relative weights of liver and heart, serum enzyme activities (${\gamma}$-glutamyl transferase, alanine amino transferase and aspartate amino transferase), thyroid hormones ($T_3$ and $T_4$), hemoglobin level and hematocrit. Significant improvement in ADG was recorded during the 2nd week of age with the addition of enzyme, whereas for all other periods, including the whole period of the trial, higher but non-significant ADG was observed. FI and FCR were not affected by the addition of enzyme but there was a numerical reduction in FCR during the whole period. The addition of enzyme reduced the ileal viscosity at all levels of '00' RSM inclusion. The results suggest that '00' RSM can be included up to 300 g/kg in broiler diets without any adverse effects on health and performance. The addition of commercial enzyme mixture containing xylanase, pectinase, cellulase to broiler diets containing '00'RSM has some effect on growth rate and feed conversion efficiency.

• 한국미생물·생명공학회지
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• 제48권1호
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• pp.12-23
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• 2020

Edible films containing antimicrobial agents can be used as safe alternatives to preserve food products. Essential oils are well-recognized antimicrobials. However, their low water solubility, volatility and high sensitivity to oxygen and light limit their application in food preservation. These limitations could be overcome by embedding these essential oils in complexed product matrices exploiting the encapsulation efficiency of β-cyclodextrin. This study focused on the maximization of β-cyclodextrin production using cyclodextrin glucanotransferase (CGTase) and the evaluation of its encapsulation efficacy to fabricate edible antimicrobial films. Response surface methodology (RSM) was used to optimize CGTase production by Brevibacillus brevis AMI-2 isolated from mangrove sediments. This enzyme was partially purified using a starch adsorption method and entrapped in calcium alginate. Cyclodextrin produced by the immobilized enzyme was then confirmed using high performance thin layer chromatography, and its encapsulation efficiency was investigated. The clove oil/β-cyclodextrin inclusion complexes were prepared using the coprecipitation method, and incorporated into chitosan films, and subjected to antimicrobial testing. Results revealed that β-cyclodextrin was produced as a major product of the enzymatic reaction. In addition, the incorporation of clove oil/β-cyclodextrin inclusion complexes significantly increased the antimicrobial activity of chitosan films against Staphylococcus aureus, Staphylococcus epidermidis, Salmonella Typhimurium, Escherichia coli, and Candida albicans. In conclusion, B. brevis AMI-2 is a promising source for CGTase to synthesize β-cyclodextrin with considerable encapsulation efficiency. Further, the obtained results suggest that chitosan films containing clove oils encapsulated in β-cyclodextrin could serve as edible antimicrobial food-packaging materials to combat microbial contamination.