• Bulletin of the Korean Chemical Society
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• v.24 no.8
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• pp.1141-1149
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• 2003

The structures and gas-phase ionization energies (ΔG°) of Meldrum's acid (I) and related cyclic (II-VI) and acyclic compounds (VII-IX) are investigated theoretically at the MP2/6-31+$G^*$, B3LYP/6-31+$G^*$, B3LYP/6- 311+$G^{**}$, B3LYP/6-311++G(3df,2p) and G3(+)(MP2) levels. Conformations of three neutral cyclic series vary gradually from boat (Meldrum's acid, I), to twisted chair (II) and to chair (III) as the methylene group is substituted for the ether oxygen successively. The preferred boat form of I can be ascribed to the two strong $n_O$ → σ* c-c antiperiplanar vicinal charge transfer interactions and electrostatic attraction between negatively charged C¹ and positively charged C⁴at the opposite end of the boat. All the deprotonated anionic forms have half-chair forms due to the two strong $n_C$ → π* c=0 vicinal charge transfer interactions. The dipole-dipole interaction theory cannot account for the higher acidity of Meldrum's acid (I) than dimedone (III). The origin of the anomalously high acidity of I is the strong increase in the vicinal charge transfer ($n_C$ → π* c=0) and 1,4-attrative electrostatic interactions (C¹↔C⁴) in the ionization (I → $I^-$ + $H^+$). In the acyclic series (VII-IX) the positively charged end atom, C⁴, is absent and the attractive electrostatic stabilization (C¹↔C⁴) is missing in the anionic form so that the acidities are much less than the corresponding cyclic series.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.207-210
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• 2000

Pseudomonas oleovorans was cultivated to produce medium chain length polyhydroxyalkanoates (MCL-PHA) fram octanoic acid and ammonium nitrate as carbon and nitrogen source, respectively, by a pH-stat fed-batch culture technique. The octanoate concentration of the culture broth was maintained below 4 g/L by feeding the mixture of octanoic acid and ammonium nitrate when the culture pH rose above high limit. The effect of the ratio of octanoic acid to ammonium nitrate (C/N ratio) in the feed on the PHA production was examined. The final cell concentrations of 62.5, 54.7, and 9.5 g/L, PHA contents of 62.9, 75.1, and 67.6% of dry cell weight, and productivities of 1.03, 0.632, and 0.161 g/L/h were obtained when the C/N ratio in the feed were 10, 20, and 100 g octanoic acid/g ammonium nitrate, respectively.

• Journal of Life Science
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• v.10 no.3
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• pp.273-278
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• 2000

The chemical compositions as amino acids, minerals, fatty acids, and total polyphenolic compounds of the seeds of leek (Allium tuberusum) were analyzed. The antioxidative activity of water soluble extract from leek seeds was also tested in DPPH ($\alpha$, $\alpha$ - diphenyl-$\beta$ -picrylhydrazyl) method. The chemical compositions of leek seeds were moisture 4.4%, curde protein 25.7%, crude fat 16.6%, and crude ash 2.9%. Major amino acid compositions were proline 11 g, glutamic acid 4.9 g, arginine 2.1g, aspartic acid 1.6g, leucine 1.3g, valine 1.2 g, and methionine 1.1 g as per 100g. Mineral contents were K 215 ppm, Ca 142 ppm, Fe 124 ppm, and Mg 100 ppm. Major fatty acid compositions were linoleic acid 71.9%, oleic acid 12.7%, palmitic acid 8.6%, and stearic acid 1.4%. The changes of contents in polyphenolic compound from leek seeds caused by heat treatment were also listed in the following order; $20^{\circ}C$(364mg/100g), $40^{\circ}C$(462 mg/100g), and $60^{\circ}C$(551 mg/100g). Antioxidative activity as electron donating ability showed in the following order; 0.05% BHT(butylated hydroxytoluene)(45.6%)>0.05% water-extract(31.3%)>0.1% water extract(30.3%). On the basis of chemical analysis, the leek seedsshowed to have relatively high contents of nutrients as amino acids, minerals, fatty acids.

• Journal of Sericultural and Entomological Science
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• v.40 no.1
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• pp.78-85
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• 1998

Colorants were prepared by extraction of natural indigo which was harvested just in the blooming season(in the late of July). 100 g of fresh leaves soaking in 1 ιwater was kept at 3$0^{\circ}C$, 30 hours. A solution of 3g/l calcium hydroxide was added into it to precipitate dye substance and it was freezing-dried into powder form. The fermentation and dyeing conditions were investigated. The results obtained are summarized as follows; K/S value of dyed silk fabrics of fermentation conditions was higher at 95$^{\circ}C$ for 20 min. than at 4$0^{\circ}C$ for 20 hours. Furthermore, K/S value of dyed silk fabric was raised by the addition of 5g/l of glucose and 5g/l of NaOH. K/S value of dyed silk fabric was raised by the addition of 5g/l of glucose and 5g/l of NaOH. K/S value increased as extending of dyeing time when dyed till 2 hours at 3$0^{\circ}C$. K/S value decreased in order of 3$0^{\circ}C$, 4$0^{\circ}C$ and 5$0^{\circ}C$, at the various dyeing temperatures and dyeing concentrations, and colour fastness ranged from 4 to 5 grade in terms of washing, perspiration and light fastness.

• The Korean Journal of Food And Nutrition
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• v.15 no.2
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• pp.144-150
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• 2002

Sweet persimmon were tested in order to identify their use as secondary material which is excellent in function and taste as food. Samples were soaked for 1 and 5 min with NaCl concentration(0, 1 and 3%) at a certain heating temperature(25, 75 and 95$\^{C}$), and then tannin, vitamin C, flavonol, color intensity, sensory test and textural properties were analysed. The results of the analyses were as follows. Tannins were decreased as heating temperature, NaCl concentration and soaking time were increased, especially, that the control was 420 mg% but decreased 228 and 198 mg% at 95$\^{C}$(1 and 3% NaCl concentration) for 5 min. soaked in each. Vitamin C content also decreased more in higher temperature and NaCl concentration than control(122.4 mg%). Color intensity showed higher value in 1. and b than in heating temperature, NaCl concentration and soaked time longer remarkably, but a value decreased. The peel of sweet persimmons was analyzed myricetin(2.0 $\mu$g/g), quercetin(34.5 $\mu$g/g) and kaemperol(1.1$\mu$g/g), but in pre-treatment sample(95$\^{C}$, 1% NaCl concentration and 5 min. soaked) was showed higher myricetin(9.5 $\mu$g/g) and quercetin(5.5 $\mu$g/g). Textural properties were good in pre-treatment sample(95$\^{C}$, 1% NaCl concentration and 5 min. soaked) such as brittleness, cohesiveness, gumminess and chewiness. In sensory analysis, the pre-treatment samples(95$\^{C}$, 1% NaCl concentration and 5 min. soaked and 95$\^{C}$, 3% NaCl concentration and 1 min. soaked) were showed higher point than others.

• Bulletin of the Korean Mathematical Society
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• v.50 no.3
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• pp.935-949
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• 2013

In this paper, we study surfaces in $\mathb{E}^3$ whose Gauss map G satisfies the equation ${\Box}G=f(G+C)$ for a smooth function $f$ and a constant vector C, where ${\Box}$ stands for the Cheng-Yau operator. We focus on surfaces with constant Gaussian curvature, constant mean curvature and constant principal curvature with such a property. We obtain some classification and characterization theorems for these kinds of surfaces. Finally, we give a characterization of surfaces whose Gauss map G satisfies the equation ${\Box}G={\lambda}(G+C)$ for a constant ${\lambda}$ and a constant vector C.

• Korean Journal of Human Ecology
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• v.8 no.1
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• pp.25-31
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• 2005

Chemical components of the physiological activity substance in Zizyphus jujuba seed were analyzed for the use as an functional processed products. The proximate compositions of Zizyphus jujuba seed were carbohydrate 89.40%, moisture 8.23%, crude protein 1.22%, crude fat 0.65% and crude ash 0.50%, respectively. the richest mineral contained in Zizyphus jujuba seed was Mg(198.3mg/100g), followed by Mn(113.0mg/100g), K(100.2mg/100g), Ca(25.3mg/100g), P(25.6mg/100g_, Fe(23.5mg/100g), Zn(18.7mg/100g), Cu(7.4mg/100g) and Na(5.3mg/100g). Total amino acid contents of Zizyphys jujuba seed were 1103.12mg/100g, and the major amino acids were proline(235.17mg%), aspartic acid(175.941mg%), gltamic acid(101.46mg%), leucine(50.27mg%), serine(47.71mg%), aspartic acid(47.27mg%), glycine(41.60mg%) and lysine (33.78mg%), respectively. The amount of free amino acids in the protein of Zizyphus jujuba seed were 178.62 mg/100g, and the major free amino acids were proline(121.30mg%), alanine(6.01mg%), valine(2.63mg%) and arginine(2.04mg%), respectively. The compositions of major total fatty acid in the lipid Zizyphus jujuba seed were C18:2(n5c) 28.72%, C18:1(n9t) 23.76%, C18:1(n9c) 13.45%, C16:0 13.45% and C20:5(n3) 1.77% in order, respectively.

• Journal of Applied Biological Chemistry
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• v.63 no.4
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• pp.327-334
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• 2020

Oxidative stress is common cause of neurodegenerative diseases. The purpose of this study is to investigate the in vitro free radical scavenging activity and protective effect of three Glycyrrhiza species including Glycyrrhiza uralensis, G. glabra, and a new variety of Glycyrrihza (Shinwongam, SW) against hydrogen peroxide-induced oxidative stress in C6 glial cells. In vitro assays, radical scavenging activities of G. uralensis, G. glabra, and SW against 2,2-diphenyl-1-picrylhydrazyl, ·OH, and O2- increased as concentration-dependent manner. In addition, the SW was found to contain the highest polyphenol and flavonoid contents. The treatment of H2O2 to C6 glial cell induced oxidative stress, whereas G. uralensis, G. glabra, and SW significantly increased the cell viability as dose-dependent manner. In particular, SW exerted stronger protective effect on H2O2-induced cytotoxicity, than G. uralensis and G. glabra. Furthermore, reactive oxygen species (ROS) formation was significantly elevated by H2O2 in C6 glial cells. However, treatments of G. uralensis, G. glabra, and SW decreased ROS formation. In addition, SW decreased pro-inflammatory related protein expression levels such as inducible nitric oxide synthase and cyclooxygenase-2, compared to H2O2-treated control group. These results indicated that G. uralensis and G. glavra, especially SW, may be useful for preventing from oxidative stress-induced neuronal damage by regulating inflammatory reaction.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.10
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• pp.1353-1358
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• 2000

The three-way rotational crossing experiment has been conducted to evaluate heterosis effects on jumping height and body weight. Yonakuni wild mice (Y) and two genetic groups of $CF_{{\sharp}1}$ (C) and C3H/HeNCrj (H) laboratory mice were used as materials. Reciprocal rotational crossing was made by crossing C male${\times}$Y female and Y male${\times}$C female to produce basic group designated $G_0$ and ${G_0}^{\prime}$, respectively. The females of the $G_0$ and ${G_0}^{\prime}$ were mated to the H sire to produce second generation ($G_1$ and ${G_1}^{\prime}$), and at the following generation the replacement females were mated to Y or C sire according to the basic group to produce $G_2$ to $G_3$ and ${G_2}^{\prime}$ to ${G_3}^{\prime}$. Individual jumping height data at Wk6 and body weight data at 1 (Wk1), 3 (Wk3), 6 (Wk6) and 10 (Wk10) weeks of age were analyzed. The results showed that effects of genetic group, sex and interaction of genetic group by sex were significant (p<0.01) for jumping height. For males, 55.34%~79.17% and 54.46%~78.29% of heterosis were reached at $G_1$ to $G_3$ and ${G_1}^{\prime}$ to ${G_3}^{\prime}$, respectively. While for females at $G_1$ to $G_3$ and at ${G_1}^{\prime}$ to ${G_3}^{\prime}$, heterosis effects were 61.53%~80.42% and 47.79%~85.86%, respectively. For body weight, genetic group was a significant source of variation at all ages studied. Sex effect was significant at Wk3, Wk6 and Wk10, and interaction between genetic group and sex was significant at Wk6 and Wk10 (p<0.01). C sires resulted in the highest body weight of offspring, while H sires were the intermediate and Y sires were the lightest. The significant positive and negative heterosis effects for body weight were exhibited. Crossing involved the Y sires in addition to smaller maternal effects of Y dams tended to result in small heterosis.

• Korean Chemical Engineering Research
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• v.56 no.3
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• pp.320-326
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• 2018

In this study, Graphite/Silicon/Carbon (G/Si/C) composites were synthesized to improve the electrochemical properties of Graphite as an anode material of lithium ion battery. The prepared G/Si/C composites were analyzed by XRD, TGA and SEM. Also the electrochemical performances of G/Si/C composites as the anode were performed by constant current charge/discharge, rate performance, cyclic voltammetry and impedance tests in the electrolyte of $LiPF_6$ dissolved inorganic solvents (EC:DMC:EMC=1:1:1 vol%). Lithium ion battery using G/Si/C electrode showed better characteristics than graphite electrode. It was confirmed that as the silicon content increased, the capacity increased but the capacity retention ratio decreased. Also, it was shown that both the capacity and the rate performances were improved when using the Silicon (${\leq}25{\mu}m$). It is found that in the case of 10 wt% of Silicon (${\leq}25{\mu}m$), G/Si/C composites have the initial discharge capacity of 495 mAh/g, the capacity retention ratio of 89% and the retention rate capability of 80% in 2 C/0.1 C.