• Analytical Science and Technology
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• v.9 no.3
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• pp.292-301
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• 1996

The synthesis of poly(ether)tailed bipyridine complex as redox reaction probes has advanced attempts to interpret very slow diffusion and heterogeneous electron transfer. Diffusion coefficients as low as $1.5{\times}10^{-15}cm^2/s$ have been observed for the oxidation of neat $Co(bpy(ppgm)_2)_{3^-}(ClO_4)_2$ with $LiClO_4$ electrolyte. Heterogeneous electron transfer rate constants of materials were found to vary with diffusion coefficient. The decrease in k as the diffusion coefficient decreases was actually caused by the decreasing D. Diffusion coefficient for compound of strong ion pairing anion($ClO{_4}^-$) was much smaller than the diffusion coefficient for compound of weak ion pairing anion($CF_3COO^-$).

• Korean Journal of Medicinal Crop Science
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• v.2 no.2
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• pp.168-173
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• 1994

Contents of essential oil and its composition in aerial part of Agastache rugosa were investigated. Essential oil was obtained from the dried stems, leaves and flowers by steam distillation and fractionated into hydrocarbon and oxygenated hydrocarbon by silica gel column chromatography. Each isolate or fraction was identified by GC and GC-MS. The contents of essential oil were 0.29% in leaves of Agastache rugosa on dry basis, 0.38% in flowers. Major components were ${\beta}-caryophyllene(59.3%)$, limonene(13.1%), ${\delta}-cadinene(10.7%)$ among 13 kinds of components confirmed in hydrocarbon fraction of essential oil isolated from leaves. Also, major components in oxygenated hydrocarbon fraction were methyl chavicol (79.1%) and cis-3(1-propenyl) phenol(4.5%) among 44 kinds components confirmed. The highest content among the components identified was methyl chavicol in both leaves and flowers. On the other hand, limonene, trans-2-hexenal, 1-octen-3-one, 6, 10, 14- trimethyl pentadecane- 2-one and phytol were detected typically in leaves, but jasmone and ${\rho}-methoxyacetophenone$ were detected mainly in flowers with small quantity.

• Applied Biological Chemistry
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• v.39 no.4
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• pp.320-326
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• 1996

Seven antioxidative flavonoids were isolated from Jindalrae flowers (Rhododendron mnonulatum Turcz.), an edible plant in Korea. These compounds were identified as afzelin, ampelopsin, catechin, myricetin, myricitrin, quercetin and quercitrin on the basis of IR, UV, FAB-MS, $^1H\;NMR,\;and\;^{13}C\;NMR$ data. These compounds were consisted of two flavonols, three flavonol glycosides, a flavane, and a dihydroflavonol. The flavonol glycosides (14.4 g) present in th ethyl ether and ethyl acetate fractions comprised up to 82% of their total flavonoid amount (17.6 g) finally recovered by means of polyamide C-200 column chromatography, preparative TLC, recrystallization, and Sephadex LH-20 column chromatography. The antioxidant activities were measured in an ethanol solution of linoleic acid in the presence of ferric thiocyanate. The antioxidant efficiency increased in the order of afzrlin<$\alpha-tocopherol$

• Elastomers and Composites
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• v.44 no.4
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• pp.416-422
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• 2009

4-(6-bromohexyloxy)benzoic acid was synthesized from benzyl 4-Hydroxybenzoate and 1,6-dibromohexane. It was reacted with hydroquinone to obtain a new mesogenic ester having an bromine group. One kind of new photoresponsive coumarin compound was prepared by the reaction of mesogenic ester with coumarin sensitive to the ultraviolet. Structures of the compound were identified by FT-IR and $^1H$-NMR spectroscopies. Their phase transition temperatures and thermal stability were also investigated by differential scanning calorimetry (DSC), polarized optical microscopy (POM) and x-ray diffraction analysis. From optical polarizing microscopy, the prepared compound was found to show enantiotropic liquid crystallinity with smectic and nematic textures.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.2
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• pp.147-152
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• 2009

In this study, the applicability of alginate-immobilized Pseudomonas putida mt-2 KG1206 on the environments, contaminated with toluene analogs was conducted. Genetically engineered strain KG1206 produces light by direct (m-toluate, benzoate) and indirect (toluene, xylenes) inducers. The protocol for the alginate-immobilization was determined in terms of the cell to alginate ratio, solution, proper number of alginate beads, and other conditions. Maximum bioluminescences of five chemicals by immobilized strain were generally observed in following orders: m-toluate > p-xylene > toluene > o-xylene > m-xylene. In relationship between bioluminescence activity and inducer reduction, initial m-toluate (5 mM) in solution was removed approximately 48% of initial at 5 h exposure, showing continuous decrease of inducer chemical in solution. These results of study with alginate-immobilized beads would be useful, especially, for biomonitoring of contaminated environments with specific compounds, such as petroleum hydrocarbon compounds including toluene analogs.

• Journal of Sericultural and Entomological Science
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• v.45 no.1
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• pp.25-30
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• 2003

This study was carried out to investigate active constituents of Bombysis corpus on the neurite outgrowth from PC 12 cells led to isolate three new and a known sphingolipids from the n-hexane soluble portion and five amines from the butanol soluble portion of its methanol extract. On the basis of spectroscopic data, their structures have been elucidated as (4E,6E,2S,3R)-2-N-eicosanoyl-4,6-tetradecasphingadienine, (4E,2S,3R)-2-N-eicosanoyl-4-tetradecasphingenine,(4E,6E,2S,3R)-2-N-docosanoyl-4,6-tetradecasphingadienine,(4E,6E,2S,3R)-2-N-docosanoyl-4,6-tetradecasphingadienine,(4E,2S,3R)-2-N-octadecanoyl-4-tetradecasphingenine, 1,7-dimethyl-xanthine, uracil, urea, betaine and tyrosine, respectively. The neurite outgrowth activities of these compounds were examined in PC12 cells by measuring the length of neurites. These compounds promoted neurite outgrowth in PC12 cells significantly.

• Journal of the Korean Chemical Society
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• v.38 no.3
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• pp.241-245
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• 1994

The oxidative addition reaction has been employed to synthesize heteropolynuclear compounds containing Si-M bonding interaction between the silicon atom of silatrane, pentacoordinate silicon derivative with transannular Si-N dative bond, and the main group element. The reaction of $SnBr_2 with 1-bromosilatrane(1a) in acetonitrile gives the mixture of yellow(2a) and white(2b) solids which were isolated and charaterized by ^1H-NMR, ^{29}Si-NMR, ^{119}Sn-NMR and Mass spectroscopy. The yellow compound was characterized as 1-tribromotinsilatrane which had Si-Sn bonding interaction. The reaction of SnBr2 with 1-bromo-3,7,10-trimethylsilatrane(1b) in methanol gives the Sn(Ⅳ) complex, N[CH_2CH(CH_3)O]_3SiSnBr_3(CH_3OH)_2(3),$ which was characterized by various means.

• Journal of the Korean Chemical Society
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• v.54 no.2
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• pp.192-197
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• 2010

The spinel compound was obtained by the thermal decomposition of Zn-Co and Zn-Ni gel prepared by sol-gel method using oxalic acid as a chelating agent. The formation of spinel compound has been comfirmed by thermogravimetric analysis (TGA), x-ray powder diffraction (XRD) and infrared spectroscopy (IR). The particle size of 13 nm~16 nm was calculated by Scherrer's equation. The sol-gel method provides a practicable and effective route for the synthesis of the spinel compound at low temperature ($350^{\circ}C$). The kinetic parameters such as activation energy (Ea) and pre-exponential factor (A) for each compound were found by means of the Kissinger method and Arrhenius equation. The decomposition of spinel compound has an activation energy about 155 kJ/mol. Finally, the thermodynamic parameters (${\Delta}G^{\varphi}$, ${\Delta}H^{\varphi}$, ${\Delta}S^{\varphi}$) for decomposition of spinel compound was determined.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.477-483
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• 2023

The flowers of Carthamus tinctorius (Safflower) were extracted with 80% aqueous methanol (CTex) and the concentrates were partitioned into EtOAc (CTE), n-BuOH (CTB), and H₂O (CTW) fractions. Repeated silica gel (SiO₂) and octadecyl silica gel column chromatographies for the EtOAc and n-BuOH fractions led to isolation of four flavonol glycosides. Nuclear magnetic resornance, infrarad spectroscopy, and mass spectroscopy revealed the chemical structure of the isolated compounds, astragalin (1), isoquercetin (2), nicotiflorin (3), and rutin (4). Quantitative analysis of four isolated compounds in CTex was performed by HPLC. CTex was found to contain 1 at 0.107, 2 at 0.367, 3 at 6.752, and 4 at 0.991 mg/g, respectively. Through this study, an experiment was conducted to evaluate the protective effect on pancreatic islets of the extract, solvent fractions, and all isolated compounds using a zebrafish larvae damaged by alloxan. Pancreatic islet size treated with EtOAc (CTE), n-BuOH (CTB), and H₂O (CTW) fractions and compounds 1-4 significantly increased compared to the alloxan-induced group. These results indicate that C. tinctorius flowers and its isolated compounds are used as potential anti-diabetic agents.

• Journal of the Korean Wood Science and Technology
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• v.44 no.1
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• pp.147-155
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• 2016

Pulp made from sugarcane bagasse (SCB) was bleached in element chlorine free (ECF) sequence. The peroxide bleaching process for the final bleaching process has been introduced in order to reduce the use of chlorine dioxide. Prior to peroxide bleaching, different chelating chemicals were applied. When 4.5% of the total chlorine dioxide was used, bleached SCB pulp using additional DTPA chelate stage (DEDQP) resulted in 87.0% of the ISO brightness. However, bleached pulp using simultaneous stage of DTPA chelate and chlorine dioxide (DE(DQ)P) was reached at 83.9% of the ISO brightness. The viscosity of DEDQP bleached pulp was 25.6 cPs, and the one of DE(DQ)P bleached pulp was 21.9 cPs. Decreasing of chelate effect by chlorine dioxide led to a decrease in the final brightness and a lower viscosity. But simultaneous stage of EDTA chelate and chlorine dioxide (DE(DQ)P) led to higher final brightness (87.0% ISO) and higher viscosity (25.8 cPs) than those of the $DEDQ_{EDTA}P$ bleached pulp (86.4% ISO, 25.2 cPs).