• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.6
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• pp.777-784
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• 1993

The bleaching effect of potato lipoxygenase Isoenzymes on ${\beta}-carotene$ was studied. Two lipoxygenase Isoenzymes(LOX-1, LOX-2) from potato tuber were purified by CM-cellulose, DEAE-cellulose ion exchange chromatography. LOX-1 and LOX-2 seemed to have bleaching effect on ${\beta}-carotene$ in the presence of linoleic acid, which the decrease in the formation of conjugated dienes. LOX-2 was founded to have a greater pigment bleaching activity than that of LOX-1.

• Bulletin of the Korean Chemical Society
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• v.26 no.1
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• pp.157-160
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• 2005

Allylindium and propargylindium reagents in situ generated from the reactions of indium with allyl halides and propargyl halides could participate as nucleophiles in Pd-catalyzed substitution reactions of allyl carbonates to produce 1,5-dienes and 1,5-enynes in good yields. $\beta$-Hydride elimination products were produced in case of carbonates having $\beta$-hydrogens. Because organoindium reagents obtained from allyl or propargyl halides and indium have previously not been used to Pd-catalyzed allylic and propargylic substitution reactions, these results should provide more opportunities for the development of new C-C bond forming reactions.

• Proceeding of EDISON Challenge
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• 2017.03a
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• pp.128-131
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• 2017

We explore the inverse electron demand Diels-Alder reactions of tetrazines with various functional groups employing quantum calculations. In general, the rate of inverse electron demand Diels-Alder reaction depends on molecular orbital levels of electron donor and electron acceptor. Likewise, ${\pi}$ orbital of the dienophile and ${\pi}^*$ orbital of the diene is a key factor. In this work, we discuss the case where the energy of diene's ${\pi}^*$ molecular orbital is not the sole governing factor to determine the reaction rate, rather the rate shows strong correlation with the charge density of dienes.

• Bulletin of the Korean Chemical Society
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• v.23 no.6
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• pp.829-837
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• 2002

Recently it was reported that cycloaddition of 6,6-disubstituted cyclohexa-2,4-dienone, 1 with cyclopentadiene gave solely the adduct of type 1.while its reaction with 1,3-cyclohexadiene gave both Ⅱ and Ⅲ. Semiempirical MO calculations were done to elucidate the origin of the selectivity difference between the two dienes. Cycloaddition of 1 with cyclopentadiene is controlled thermodynamically to give only 1-diene adduct by ΔGvalues of 10.6-20.3 kcal/mol, while its reaction with 1,3-cyclohexadiene does not show 1-diene/1-dienophile selectivity due to similar stabilities of the two adducts. Thermodynamic parameters also show that 두애 adducts are more fabourably fromed in the cycloadditions of 1 with both cyclopentadiene and 1,3-cyclohexadiene, which coincides with experimental observations. Cope rearrangements of endo adducts are another avenue to convert between 1-diene and 1-dienophile.

• East Asian mathematical journal
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• v.28 no.4
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• pp.453-474
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• 2012

The conic sections is an important topic in the current high school geometry. It has been recognized by many researchers that high school students often have difficulty or misconception in the learning of the conic sections because they are taught the conic sections only with algebraic perspective or analytic geometry perspective. In this research, we suggest a way of teaching the conic sections using a dynamic geometry software based on some mathematics teaching and learning theories such as Freudenthal's and Dienes'. Students have various experience of constructing and manipulating the conic sections for themselves and the experience of deriving the equations of the quadratic curves under the teacher's careful guidance. We identified this approach was a feasible way to improve the teaching and learning methods of the conic sections.

• The Korean Journal of Food And Nutrition
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• v.37 no.1
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• pp.48-56
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• 2024

Effects of glutamic acid (Glu) and monosodium glutamate (MSG) on oxidative stability of oil-in-water (O/W) emulsions with different emulsifier charges during riboflavin (RF) photosensitization were evaluated by analyzing headspace oxygen content and conjugated dienes. Cetyltrimethylammonium bromide (CTAB), Tween 20, and sodium dodecyl sulfate (SDS) were used as cationic, neutral, and anionic emulsifiers, respectively. Glu acted as an antioxidant in CTAB- and Tween-20-stabilized O/W emulsions during RF sensitization, whereas Glu acted as prooxidants in SDS-stabilized O/W emulsions in the dark. However, adding MSG did not have a constant impact on the degree of oxidation in O/W emulsions irrespective of the emulsifier charge. In RF-photosensitized O/W emulsions, the emulsifier charge had a greater influence on antioxidant properties of Glu than on those of MSG.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.7
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• pp.1147-1153
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• 2004

The effect of commercial deer antler drink (provided by Chung-yang Deer Farm) on blood glucose level, plasma lipids and antioxidants state in type 2 diabetic patients were studied. Ten patients with type 2 diabetes participated in the study and consumed 2 pouches (200 mL) of deer antler drink every day for 3 weeks. No significant differences were observed in levels of triglycerides, total cholesterol, low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C). However, oxidized LDL measured as conjugated dienes decreased in the patients after the trial. Plasma tocopherols and carotenoids levels showed no significant changes. No significant differences were observed in erythrocyte SOD, catalase and GSH-Px in the each group. No significant differences were observed in plasma TRAP. The results would suggest that deer antler drink influences conjugated dienes but long-term intervention trial may be necessary to see further beneficial effect of deer antler drink in diabetic patients.

• 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.

• Food Science of Animal Resources
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• v.32 no.4
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• pp.491-496
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• 2012

The objective of this research was to investigate the effect of the fattening period (18, 21, and 24 mon) on the oxidative stability of Holstein beef patties. The ground Holstein steer beef samples (M. longissimus dorsi) were stored at $4^{\circ}C$ for 12 d and used for lipid oxidation, protein oxidation, myoglobin oxidation, and color measurements. Fat content was significantly (p<0.05) higher in the 24 mon group than in the 18 mon group. 2-thiobarbituric acid reactive substances content and metmyoglobin concentration were the highest (p<0.05) in the 24 mon group from 8 d of storage. Conjugated dienes content was significantly (p<0.05) higher in the 21 and 24 mon groups. Carbonyl content was the highest (p<0.05) in the 24 mon group at 12 d of storage. In surface meat color, the CIE $L^*$ value showed a lower level in the 21 and 24 mon groups from 4 d of storage. Although the CIE $a^*$ value was further lowered, the CIE $b^*$ value maintained a higher value in the 24 mon group during storage, compared to the other groups. Therefore, greater fattening period increased lipid oxidation, protein oxidation, and myoglobin oxidation in Holstein beef patties. Partially, the 24 mon group had the lowest oxidative stability.

• Journal of the Korean Chemical Society
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• v.34 no.5
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• pp.430-437
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• 1990

Various tris (${\eta}^4$-diene) molybdenums were easily synthesized by the reaction of various 1,3-dienes and molybdenum metal vapors by using metal atom reactor. The methyl substituent effect of the tris (${\eta}^4$-diene) molybdenum produced were discussed. And some alkadiene-molybdenum complexes which were easily decomposed in the air at room temperature were also formed.(C$_6$H$_{10}$)$_2$(CO)$_3$Mo were synthesized and its molybdenum-diene bond type were discussed.