• Korean Journal of Food Science and Technology
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• v.30 no.5
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• pp.1214-1221
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• 1998

The study was carried out to investigate the antioxidant effects of ethanol, methanol, and water extracts or fractions of ethanol extract of Ligularia fischeri on low density lipoprotein(LDL) and ethanol extract was further fractionated. The methanol extract and ethyl acetate fraction showed strong antioxidant effect with 71.7% (13.36 nmol/mg) and 95% (1.35 nmol/mg) inhibition in the presence of $15\;{\mu}g/mL$, respectively. In the value of malondialdehyde(MDA) with oxidation time, ethanol, methanol and water extract in the presence of $25\;{\mu}g/mL$ inhibited the oxidation up to 4h incubation and ethyl acetate fraction showed strong antioxidant effect up to 8h incubation. Also, the ethanol, methanol and water extract showed antioxidant effects in the agarose gel electrophoresis test. The conjugated diene formation by lipid oxidation with addition of $Cu^{2+}$ in the Ligularia fischeri extracts and their fractions was decreased approximately 1.1 to 2.8 times and 2.2 to 3.2 times, respectively compared to control. In the degradation of apo B-100 by oxidation using SDS-PAGE, ethanol, methanol and water extract showed similar degradation band pattern compared to that of native LDL band. Apo B-100 contents using densitometer were 77.8, 92.5% and 82.3% in the ethanol, methanol and water extract, respectively, compared to 100% of native LDL. In the meanwhile, apo B-100 contents in hexane, ethyl acetate and water fraction were 38.8, 94.5 and 65.5% respectively. This results indicated that ethyl acetate fraction showed the strongest antioxidant effect on MDA value or apo B-100 contents of LDL.

• Applied Biological Chemistry
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• v.47 no.2
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• pp.251-257
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• 2004

The root of lxeris dentata forma albiflora was extracted with 80% aqueous MeOH and solvent fractionated with EtOAc, n-BuOH and water, successively. From the EtOAc and n-BuOH fractions, four sesquiterpene compounds were isolated through the repeated silica gel and ODS column chromatographies. The chemical structures were determined as zaluzanin C (1), $9{\alpha}-hydroxyguaian-4(l5),10(14),11(13)-triene-6,12-olide$ (2), $3{\beta}-O-{\beta}-D-glucopyranosyl-8{\alpha}-hydroxyguaian-4(15),10(14 )-diene-6,12-olide$ (3), and $3{\beta}-O-{\beta}- D-glucopyranosyl-8{\beta}hydroxyguaian-10(14)-ene-6,12-olide$ (4) through the interpretation of several spectral data including 2D-NMR. Some showed the inhibitory effects on DGAT (Diacylglycerol acyltransferase), ($IC_{50}$ values of 1, 2: 0.13, 0.10 mM), the catalyzing enzymes of the intracellular esterification of diacylglycerol and FPTase (Famesyl-protein transferase), ($IC_{50}$ values of 1, 2: 0.15, 0.18 mM), the farnesylation enzyme for Ras protein charge of cancer promotion.

• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.781-786
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• 1998

To assess effect of surface area on the oxidative stability in thermooxidative system, soybean oil and lard with different surface area $(0.04{\;}cm^2/g,{\;}0.08{\;}cm^2/g,{\;}0.12{\;}cm^2/g{\;}and{\;}0.16{\;}cm^2/g)$ were heated 8 hrs/day at $185^{\circ}C$. The iodine values of soybean oil heated for 64 hrs with surface area of $0.12{\;}cm^2/g$ and $0.16{\;}cm^2/g$ were 113.1 and 116.9, while those of the oil heated for the same length time with surface area of $0.04{\;}cm^2/g$ and $0.08{\;}cm^2/g$ were 126.4 and 125.9, respectively. The same trend was observed in lard, but less markedly than in soybean oil. The polar lipid content, dielectric constant and refractive index of soybean oil and lard heated with surface area above $0.12{\;}cm^2/g$ significantly increased as the heating time increased, while those of the oil heated with surface area below $0.08{\;}cm^2/g$ slowly increased as the heating time increased. On the other hand, the conjugated diene content of soybean oil heated with surface area above $0.12{\;}cm^2/g$ oil increased as the heating time increased while ratio of linoleic acid to palmitic acid decreased as the heating time increased. However, the conjugated diene content and ratio of linoleic acid to palmitic acid of lard were not significantly different depending on the surface area. The results obtained from this investigation indicated that the thermooxidative stability of oil heated with surface area below $0.08\;}cm^2/g$ was better than that of oil heated with surface area above $0.12{\;}cm^2/g$ (P<0.05).

• Composites Research
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• v.34 no.3
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• pp.192-198
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• 2021

Due to enormous market growing of electric vehicles without combustion engine, reducing unwanted BSR (buzz, squeak, and rattle) noise is highly demanded for vehicle quality and performance. Particularly, innerbelt weatherstrips which not only block wind noise, rain, and dust from outside, but also reduce noise and vibration of door glass and vehicle are required to exhibit high damping properties for improved BSR performance of the vehicle. Thermoplastic elastomers (TPEs), which can be recycled and have lighter weight than thermoset elastomers, are receiving much attention for weatherstrip material, but TPEs exhibit low material damping and compression set causing frictional noise and vibration between the door glass and the weatherstrip. In this study, high damping EPDM (ethylene-propylene-diene monomer)/PP (polypropylene) thermoplastic vulcanizates (TPV) were investigated by varying EPDM/PP ratio and ENB (ethylidene norbornene) fraction in EPDM. Viscoelastic properties of TPV materials were characterized by assuming that the material damping is directly related to the viscoelasticity. The optimum material damping factor (tanδ peak 0.611) was achieved with low PP ratio (14 wt%) and high ENB fraction (8.9 wt%), which was increased by 140% compared to the reference (tanδ 0.254). The improved damping is believed due to high fraction of flexible EPDM chains and higher interfacial slippage area of EPDM particles generated by increasing ENB fraction in EPDM. The stick-slip test was conducted to characterize frictional noise and vibration of the TPV weatherstrip. With improved TPV material damping, the acceleration peak of frictional vibration decreased by about 57.9%. This finding can not only improve BSR performance of electric vehicles by designing material damping of weatherstrips but also contribute to various structural applications such as urban air mobility or aircrafts, which require lightweight and high damping properties.

• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.258-263
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• 2023

In this study, conductive polymers and the enzyme tyrosinase (Tyr) were deposited on the surface of a screen printed carbon electrode (SPCE), which can be fabricated as a disposable sensor chip, and applied to the detection of bisphenol F (BPF), an endocrine disruptor with proven links to male diseases and thyroid disorders, using electrochemical methods. On the surface of the SPCE working electrode, which was negatively charged by oxygen plasma treatment, a positively charged conductive polymer, poly(diallyldimethyl ammonium chloride) (PDDA), a negatively charged polymer compound, poly(sodium 4-styrenesulfonate) (PSS), and another layer of PDDA were layered by electrostatic attraction in the order of PDDA, PSS, and finally PDDA. Then, a layer of Tyr, which was negatively charged due to pH adjustment to 7.0, was added to create a PDDA-PSS-PDDA-Tyr sensor for BPF. When the electrode sensor is exposed to a BPF solution, which is the substrate and target analyte, 4,4'-methylenebis(cyclohexa-3,5-diene-1,2-dione) is generated by an oxidation reaction with the Tyr enzyme on the electrode surface. The reduction process of the product at 0.1 V (vs. Ag/AgCl) generating 4,4'-methylenebis(benzene-1,2-diol) was measured using cyclic and differential pulse voltammetries, resulting in a change in the peak current with respect to the concentration of BPF. In addition, we compared the detection performance of BPF using an ionic liquid electrolyte as an alternative to phosphate-buffered saline, which has been used in many previous sensing studies. Furthermore, the selectivity of bisphenol S, which acts as an interfering substance with a similar structure to BPF, was investigated. Finally, we demonstrated the practical applicability of the sensor by applying it to analyze the concentration of BPF in real samples prepared in the laboratory.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.10
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• pp.1513-1517
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• 2016

Rice bran contains high amounts of fiber and various phytochemicals, including vitamin E, ${\gamma}$-oryzanol, and phenolic acids. The oxidative stabilities of corn oil added with three rice bran extracts from two rice cultivars (Dasan 1 and Ilpum) were evaluated. The three rice bran extracts were unsaponifiable matter of rice bran (USM), methanolic extract of rice bran oil (MEO), and methanolic extract of defatted rice bran (MEDR). Each sample was stored at $50^{\circ}C$ for 24 days. Oxidation of these samples was determined every 3 days by measuring the peroxide value (POV) and conjugated diene value (CDV). Vitamin E content was analyzed on day 0 and day 24. The results show that the POV and CDV values of samples increased gradually during the storage period. The order of oxidative stability was shown as BHT> MEDR> MEO> USM> control, regardless of cultivars. In the case of vitamin E, ${\alpha}$-T, ${\gamma}$-T, ${\alpha}$-T3, and ${\gamma}$-T3 contents decreased by 89%, 31%, 83%, and 32% after storage for 24 days, respectively. In conclusion, MEDR showed higher oxidative stability and may have potential as a source of natural antioxidants in the oil industry.

• Journal of the Korean Society of Food Science and Nutrition
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• v.14 no.1
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• pp.39-46
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• 1985

The fatty acid composition, total number of fatty acid acyl carbon atoms and species of triglycerides from human milk samples obtained during 70 days of lactation from 39 mothers were determined by argentation thin-layer and gas chromatographic procedures. The medium- and long-chain saturated fatty acids(8:0, 1O:0, 12:0 and 14:0) which are formed exclusively by synthesis within mammary gland increased significantly from colostrum to mature milk. Long-chain saturated fatty acids(16 : 0, 22 : 0 and 24: 0) were significantly higher than tile levels found in transitional and mature milk. The precursors of w C- and w 3-series, 18:2 w 6 and 18:3 w 3, were increased slightly in progressing lactation. Colostrum contained significantly higher proportions of 18:1 w 9 and w 6- and w 3- derived long-chain polyunsaturated fatty acids than transitional milk, and these levels were further reduced in mature milk. The triglycerides of human milk lipids which were made up of 30-60 acyl carbon atoms showed a pattern with major contributions made by the glycerides with 44-52 acyl carbon atoms. The levels of triglycerides with less than 46 acyl carbon atoms increased significantly with the elapse of lactation period, whereas those with more than 50 acyl carbon atoms decreased significantly. The fully saturated trig1ycerides increased significantly as the lactation proceeded, but the dienoic triglycerides declined significantly.

• Nutrition Research and Practice
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• v.11 no.3
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• pp.214-222
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• 2017

BACKGROUND/OBJECTIVES: Glutathione S-transferase (GST) forms a multigene family of phase II detoxification enzymes which are involved in the detoxification of xenobiotics by conjugating substances with glutathione. The aim of this study is to assess the antioxidative status and the degree of DNA damage in the subclinical hypertensive patients in Korea using glutathione S-transferase polymorphisms. SUBJECTS/METHODS: We examined whether DNA damage and antioxidative status show a difference between GSTM1 or GSTT1 genotype in 227 newly diagnosed, untreated (systolic blood pressure $(BP){\geq}130mmHg$ or diastolic $BP{\geq}85mmHg$) subclinical hypertensive patients and 130 normotensive subjects (systolic BP < 120 mmHg and diastolic BP < 80 mmHg). From the blood of the subjects, the degree of the DNA damage in lymphocyte, the activities of erythrocyte superoxide dismutase, the catalase, and the glutathione peroxidase, the level of glutathione, plasma total radical-trapping antioxidant potential (TRAP), anti-oxidative vitamins, as well as plasma lipid profiles and conjugated diene (CD) were analyzed. RESULTS: Of the 227 subjects studied, 68.3% were GSTM1 null genotype and 66.5% were GSTT1 null genotype. GSTM1 null genotype had an increased risk of hypertension (OR: 2.104, CI: 1.38-3.35), but no significant association in GSTT1 null genotype (OR 0.982, CI: 0.62-1.55). No difference in erythrocyte activities of superoxide dismutase, catalase, or glutathione peroxidase, and plasma TRAP, CD, lipid profiles, and GSH levels were observed between GSTM1 or GSTT1 genotype. Plasma levels of ${\alpha}-tocopherol$ increased significantly in GSTT1 wild genotype (P < 0.05); however, plasma level of ${\beta}-carotene$ increased significantly in GSTT1 null genotype (P < 0.01). DNA damage assessed by the Comet assay was significantly higher in GSTM1 null genotype than wild genotype (P < 0.05). CONCLUSIONS: These results confirm the association between GSTM1 null genotype and risk of hypertension as they suggest that GSTM1 null genotype leads to an increased oxidative stress compared with wild genotype.

• Korean Journal of Food Science and Technology
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• v.23 no.6
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• pp.732-738
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• 1991

Corsoy 79 soybeans were ground into 8-(coarse) and 24-mesh (fine) full-fat soy flours. From the particle size analysis, the 8-mesh full-fat soy flours were found to have larger values for geometric mean diameter and geometric standard deviation. However, the distribution moduli of coarse and fine soy flours were similar and indicated soybeans were nearly 'brittle'. Development of hydrolytic and oxidative rancidities of coarsely and finely ground full-fat soy flours were followed from grinding to 24 hrs later. No increases in peroxide value and conjugated dienes in the oil and hexanal content in the headspace of the flour were observed when the moisture was 10.7% or less. At 14.9% moisture and above, lipid oxidation increased with increased moisture content and storage time. Free fatty acid contents increased slightly at all moisture contents. However, hydrolysis did not exceed 0.06% over the moisture range of 4 to 18%, which is of little practical significance. Fine grinding increased oxidative and hydrolytic rancidities, especially at 14.9% moisture and above. these findings indicate that raw soybeans can be ground to full-fat soy flours and stored up to 24 hrs without undergoing significant lipid and flavor deterioration if the moisture content is 11% or less.

• Clinical and Experimental Pediatrics
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• v.48 no.6
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• pp.649-654
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• 2005

Purpose : The present study examined how changes in cerebral hemodynamics in newborn piglets with bilirubin infusion can be evaluated by near infrared sepctroscopy(NIRS). Methods : Seventeen newborn piglets were randomly divided into the following three experimental groups : six in the control group(CG); seven in the bilirubin infusion group(BG), and four in the bilirubin infusion with 7-nitroindazole group(NG). To achieve the concentration of bilirubin above 20 mg/dL, we injected a bolus of 40 mg/kg of bilirubin intravenously, followed by 30 mg/kg/hr of bilirubin continuous intravenous infusion. All groups were monitored with cerebral hemodynamics using near infrared spectroscopy(NIRS) and their brain cortexes were harvested and the activities of $Na^+$, $K^+$-ATPase, level of conjugated dienes, ATP and phosphocreatine(PCr) were determined biochemically. Results : No changes took place in CG. In BG and NG, base excess, pH, and MABP decreased, and lactate level in blood increased. Cerebral $Na^+$, $K^+$-ATPase activity and ATP, PCr level in BG significantly decreased and conjugated dienes increased compared to CG. These abnormalities observed in the BG were significantly improved in the NG. In continuous NIRS monitoring, [$HbO_2$], [HbT], and [HbD] in BG were significantlly decreased compared to CG. However these abnormalities between NG and CG were not significantly different. There were no significant differences in $ScO_2$ between the study groups. Conclusion : Our study suggests cerebral hemodynamic changes could be monitored by non-invasive NIRS in newborn piglets with bilirubin infusion.