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        검색결과 36

        21.
        2014.01 KCI 등재 서비스 종료(열람 제한)
        Antarctic krill (Euphausia superba) is typical of a enormous biomass of marine zooplankton that could provide good nutrition in human body. This study was conducted to identify the nutrition of krill, a live in Antarctic Ocean. The analysis result of fatty acids of krill meal was as follow. The compositions of fatty acid were saturated fatty (SFA) acid 41.41%, monounsaturated fatty acid (MUFA) 21.69%, polyunsaturated fatty acid (PUFA) 36.89%, and p/s ratio was 0.89. The major fatty acids in all parts were eicosapentaenoic acid (EPA, 21.54%), palmitic acid (27.51%), oleic acid (13.35%) and docosahexaenoic acid (DHA, 12.42%). Especially, EPA and DHA were occupied 33.96% of polyunsaturated fatty acid. The mineral contents of krill meal were calcium 24477.21 mg kg-1, sodium 14728.69 mg kg-1, magnesium 6973.49 mg kg-1, potassium 3981.67 mg kg-1, iron 395.33 mg kg-1 and manganese 5.74 mg kg-1. The contents of major vitamin were retinol 86717.37 μg RE, β-carotene 44.87 μg RE, tocopherol 2.60 mg, pantothenic acid 1.61 mg, indicating that krill meal contains large amount of retinol and β-carotene.
        22.
        2013.04 KCI 등재 서비스 종료(열람 제한)
        This study was conducted to investigate the effects of the Cordyceps militaris extract on the improvement of the glucide metabolism in serum of streptozotocin (STZ, 50 mg/kg BW, IP injection)-induced diabetic rats (SD strain, male) fed the experimental diets for 5 weeks. Concentrations of creatinine, lipid peroxide and NEFA in sera were significantly higher in the STZ-induced diabetic group (group DMG) and STZ+Cordyceps militaris extract administration group (group DMS) than those in the control group (group BD). However, the concentrations of creatinine, lipid peroxide and NEFA in sera were reduced in the group DMS than those in the group DMG. The activity of creatine phosphokinase (CPK) in serum was lower in the group DMS than in the group DMG. The activity of LCAT in serum was increased in the group DMS (Cordyceps militaris extract administration) than in the group DMG. The results indicate that Cordyceps militaris extract were effective in the improvement of the glucide metabolism in the sera of STZ-induced diabetic rats.
        23.
        2013.03 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study was to assess the effects of Cordyceps militaris extract supplementation on the improvement of blood glucose, lipid compositions and hepatic functional enzyme activities in the serum of streptozotocin(STZ, 50 mg/kg BW, IP injection)-induced diabetic rats fed the experimental diets for 5 weeks. The concentrations of blood glucose and lipid compositions(total cholesterol, β-lipoprotein, free cholesterol, cholesteryl ester, triglyceride and phospholipid) and atherosclerotic index in serum were significantly lower in the DM+CM group than in the DM group, whereas the ratio of HDL-cholesterol concentration to total cholesterol in the DM+CM group were higher than in the DM group. The activities of hepatic functional enzymes(aminotransferase, LDH and ALP) in serum were lower in the Cordyceps militaris extract administration group(group DM+CM) than in the hyperglycemic DM group. The results shown above suggested that Cordyceps militaris extract supplementation effectively improves blood glucose and atherosclerosis in the serum of diabetic rats.
        24.
        2013.02 KCI 등재 서비스 종료(열람 제한)
        Fibers of microbial polyesters, poly(3-hydroxy butyrate) (PHB) and poly(3-hydroxy butyrate-co-3-hydroxy valerate) (HB-co-HV) were prepared by electrospinning method. The obtained fibers were evaluated by differential scanning calorimetry, scanning electron microscopy, and oil absorption. The formation of fibers was strongly dependent on a concentration of solution. At a low concentration, the fibers contained beads which is from aggregation of polymer due to short evaporation time. The fine fibers with 2-5 mm diameter were obtained at 20 wt% concentration. The contact angle measurement showed that the fiber had higher water contact angle than the film due to the lotus-like effect. Oil absorbency showed that the fiber had higher than the film. Specially, the HB-co-HV fiber which was spinned from 20 wt% absorbed 65% oil which is much higher than that of a normal polypropylene-based oil paper.
        25.
        2012.10 KCI 등재 서비스 종료(열람 제한)
        The objective of this study was to investigate the effects of the feeding Cordyceps militaris extract on the improvement of the free fatty acid, lipid peroxide, creatinine and enzyme (creatine phosphokinase; CPK, lactate dehydrogenase; LDH, alkaline phosphatase; ALP, lecithin cholesterol acyltransferase; LCAT) activities in the sera of dietary hypercholesterolemic rats (SD strain, male) fed the experimental diets for 5 weeks. Concentrations of free fatty acid, lipid peroxide and CPK, LDH, ALP activities in sera were fairly reduced in the Cordyceps militaris extract administration group (CHE) than in the hypercholesterolemic diet group (CHD). However, no significance was found in the effect of an creatinine concentration among the groups. The LCAT activity in serum was increased in the Cordyceps militaris extract administration (CHE) than in the hypercholesterolemic diet group (CHD). From these results, Cordyceps militaris extracts were effective on the improvement of the lipid components and metabolic enzyme activities in sera of dietary hypercholesterolemic rats.
        26.
        2012.07 KCI 등재 서비스 종료(열람 제한)
        This study was performed to observe the effects of the feeding physiological activity substance in Cordyceps militaris hot-water extract intake on the improvement of lipid components and metabolic enzyme activities in the serum of dietary hyperlipidemic rats (SD strain, male) fed the experimental diets for 5 weeks. The concentrations of cholesterol (total cholesterol, β-lipoprotein, LDL-cholesterol, free cholesterol and cholesteryl ester), atherosclerotic index, triglyceride (TG), phospholipid (PL) and blood glucose in sera were remarkably lower in the Cordyceps militaris extract intake group than in the hyperlipidemic rats. In the ratio of HDL-cholesterol concentration was higher percentage in the Cordyceps militaris extract intake group than in the hyperlipidemic rats. The activities aminotransferase (AST, ALT) in sera were rather lower in the Cordyceps militaris extract administration than in the hyperlipidemic rats. From the above research, Cordyceps militaris extract were effective on the improvement of the lipid compositions in sera of dietary hyperlipidemic rats.
        27.
        2012.04 KCI 등재 서비스 종료(열람 제한)
        To improve the mechanical properties of hydroxyapatite (HA)/waterborne polyurethane (WBPU) composites, the hydroxyl group of HA was modified by urethane reactions: the hydroxyl groups of HA were reacted with aliphatic or cyclic diisocyanate, and then the modified HAs were extended by adding polyol and/or ε-caprolactone. Composites were prepared by the prepolymer process method: the modified HA was directly pured into the urethane reaction of isocyanate and polyol. The properties of modified HA/WBPU composites were investigated by thermogravimetric analysis, tensile strength, and water resistance. The results showed that the reactivity of aliphatic diisocyanate to the hydroxy group of HA was faster than that of cyclic one. Comparing to those of pure HA/WBPU composite films, the thermal stability, water resistance, and mechanical properties of the modified composite films increased with a degree of modification of HA.
        28.
        2010.09 KCI 등재 서비스 종료(열람 제한)
        The effects of addition of non degradable polymers, polystyrene (PS) and poly(methyl methacrylate) (PMMA) on the rate of enzymatic degradation of biodegradable poly(l-lactide) (PLLA) have been studied in term of surface structure. Since a component in multicomponent polymeric system has shown surface enrichment, PS and PMMA which have lower surface energy than PLLA were selected as a minor blend component (5 wt%). Enzymatic degradation was carried out at 37 ºC and pH 8.5 in the aqueous solution of Proteinase K. Two blend systems, partially miscible (PS/PLLA) and immiscible (PMMA/PLLA), showed the surface enrichment of 4 and 2 times of PS and PMMA, respectively. From the weight loss profile data, the slow degradation rate of both blend films was observed. This indicates that PS or PMMA domains which exist at surface act as a retardant of enzymatic attack.
        29.
        2009.07 KCI 등재 서비스 종료(열람 제한)
        To control degradation rate of biodegradable poly(lactide)s (PLA), the stereochemical PLAs with different ratios of d-lactide and l-lactide units were synthesized by the ring open polymerization and the their degradation kinetics were measured by a Langmuir film balance. The alkaline (pH=11) degradation of poly(l-lactide) (l-PLA) monolayer showed the faster rate at a surface pressure of 4 mN/m in the ranges from to 0 to 7 mN/m. However, the enzymatic degradation of l-PLA with Proteinase K did not occur until 4 mN/m. Above a constant surface pressure of 4 mN/m, the degradation rate was increased with a constant surface pressure. These behaviors might be attributed to the difference in the contacted area with degradation medium: alkaline ions need small contact area with l-PLA while enzymes require much bigger one to be activated due to different medium sizes. The stereochmical PLA monolayers showed that the alkaline degradation was increased with their optical impurities while the enzymatic one was inversed. These results could be explained by the decrease of crystallinity with the optical impurity and the inactivity of enzyme to d-LA unit.
        30.
        2008.08 KCI 등재 서비스 종료(열람 제한)
        Manufactures of automotive repair finishes are tending to reduce more and more the level of volatile organic compounds (VOCs) in their paint processes in order to comply with increasingly strict environmental legislation. The production of high solids paints is a way to solve this problem. However, the application of high-solids paints is limited primarily by the viscosity of resin which is strongly related to painting ability: the higher solid content, the lower desired property. In this study, alkyl copolymer with low viscosity was synthesized by the introduction of the monomers with long-side chains and functional groups which improve flexibility and cross-linking density, respectively. The solid content of the paint prepared with the synthesized resin was 80 wt% and its VOCs was reduced by 20%, compared to the commercialized paint. Also, the physical and mechanical properties of coatings on steel sheets were similar to commercialized one.
        31.
        2006.02 KCI 등재 서비스 종료(열람 제한)
        The hydrolytic kinetics of biodegradable poly(l-lactide) (PLLA) have been studied by using two model systems, solution-grown single crystal (SC) and Langmuir monolayer techniques, for elucidating the mechanism for both alkaline and enzymatic degradations. The present study investigated the parameters such as degradation medium and time. The Langmuir monolayers of PLLA showed faster rates of hydrolysis when they were exposed to a basic subphase rather than they did when exposed to neutral subphase. Both degradation mediums had moderate concentrations to show a maximized activity, depending on their sizes. An alkaline degradation of SCs of PLLA showed the decrease of molecular weight of the remained crystals due to the erosion of chain-folding surface. However, the enzymatic degradation of SCs of PLLA occurred in the crystal edges thus the molecular weight of remained crystals was not changed. This behavior might be attributed to the size of enzymes which is much larger than that of alkaline ions; that is, the enzymes need larger contact area with monolayers to be activated.
        32.
        2005.01 KCI 등재 서비스 종료(열람 제한)
        Because of the toxicity of hexavelant chromium ion, treatments of metallic surface with chromate compounds to retard corrosion are undesirable for safety control in industrial uses and protection of environment. In this study, we investigated several compounds such as inorganic, organic, and polymer materials in order to substitute the chromate conversion treatment on steel sheet. The corrosion property was investigated in a salt spray tester with 3.5 wt.% NaCl at 35℃. The results showed that the zirconium/silane/polymer triple coatings on the galvanized steel exhibited a significant retardation of corrosion. Although the multicoating system needs a complexed processing, we can confirm a possibility of development of a chromate-free chemical conversion treatment for galvanized steel sheet.
        33.
        2004.04 KCI 등재 서비스 종료(열람 제한)
        With the help of mechanical mixing method such as Banbury mixer and open 2 roll mill, ethylene propylene diene terpolymer (EPDM) was blended with the chloroprene rubber (CR) then mechanical properties and ozone resistance test of blends were subsequently investigated. It was noted that the hardness increased with an increasing of CR contents. Generally the hardness was increased with heat aging time most likely due to the post cure. In ozone resistance test of blend, after 8 hours a portion of fine crack is obtained for pure CR. It is confirmed that ozone resistance is greatly improved by addition of 25wt% EPDM to CR.
        34.
        2003.07 KCI 등재 서비스 종료(열람 제한)
        This work aims the search of environmentally friendly pre-treatment technologies to develop chromate replacements for metal finishing industries due to its toxicological properties. Since the corrosion resistance of steel was strongly related to water permeation, galvanized steel sheets were treated with various hydrophobic silane compounds and water-suspended polymer solution. Also, plasma gas discharge was applied to modify the surface of a polymer coated-steel sheet to be hydrophobic. The surface hydrophobicity of materials was introduced by CF3H plasma exposure. The corrosion property before and after the plasma treatment was investigated in a slat spray tester with 3.5 wt.% NaCl at 35 ℃. The results showed that both silane/polymer double coatings and plasma treatment of the galvanized steel exhibited significant retardation of corrosion.
        35.
        2002.12 KCI 등재 서비스 종료(열람 제한)
        Since the enzymatic degradation of microbial poly[(R)-3-hydroxybutyrate-co-3-hydroxyvalerate] (P(3HB-co- 3HV)) initially occurs by a surface erosion process, a degradation behavior could be controlled by the change of surface property. In order to control the rate of enzymatic degradation, plasma gas discharge and blending techniques were used to modify the surface of microbial P(3HB-co-3HV). The surface hydrophobic property of P(3HB-co-3HV) film was introduced by CF3H plasma exposure. Also, the addition of small amount of polystyrene as a non-degradable polymer with lower surface energy to P(3HB-co-3HV) has been studied. The enzymatic degradation was carried out at 37 ºC in 0.1 M potassium phosphate buffer (pH 7.4) in the presence of an extracellular PHB depolymerase purified from Alcaligenes facalis T1. Both results showed the significant retardation of enzymatic erosion due to the hydrophobicity and the enzyme inactivity of the fluorinated- and PS-enriched surface layers.
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