• Bulletin of the Korean Chemical Society
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• v.28 no.7
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• pp.1175-1182
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• 2007

A series of new organic semiconductors hexyl end-capped thiophene-anthracene oligomers containing the anthracene moiety in the center of the oligomers are synthesized. The target oligomers have been obtained by Stille coupling reactions as key step reactions. The synthesized thiophene-anthracene oligomers were characterized by 1H-NMR, 13C-NMR and high-resolution mass spectroscopy, respectively. All of the oligomers are soluble in chlorinated solvents. Their optical, thermal and electrochemical properties were measured. The hexyl end-capped oligomers and their unsubstituted oligomers exhibit the same absorption behavior in dilute toluene solution. Hexyl end-capped bis-terthienylanthracene oligomer is observed to show liquid crystalline mesophase at 166 oC in heating process. The thermal analyses as well as the electrochemical measurement data indicate that the designed materials show better thermal and oxidation stability than the corresponding oligothiophenes without anthracene core. Fluorescence lifetimes and fluorescence quantum yields of the thiophene-anthracene oligomers are measured to be 10-14 ps and 3.4-9.9 × 10?3 which are much shorter and lower than those of oligothiophenes respectively.

• Bulletin of the Korean Chemical Society
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• v.29 no.3
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• pp.590-594
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• 2008

The inclusion complexes of cyclodextrins (CDs) with flavones in aqueous solution were investigated by phase solubility measurements. The effect of b -cyclodextrin (b -CD), heptakis (2,6-di-O-methyl) b -cyclodextrin (DM-b -CD) and 2-hydroxypropyl-b -cyclodextrin (HP-b -CD) on the aqueous solubility of three flavones, namely, chrysin, apigenin and luteolin was investigated, respectively. Solubility enhancements of all flavones obtained with three CDs followed the rank order: HP-b -CD > DM-b -CD > b -CD, and besides, CDs show higher stability constant on luteolin than that on others flavones. 1H-nuclear magnetic resonance (NMR) spectroscopy and molecular modeling was used to help establish the model of interaction of the CDs with luteolin. NMR spectroscopic analysis suggested that A-C ring, and part of the B ring of luteolin display favorable interaction with the CDs, which was also confirmed by docking studies based on the molecular simulation. The observed augmentation of solubility of luteolin by three CDs was explained by the difference of electrostatic interaction of each complex, especially hydrogen bonding.

• Journal of Animal Science and Technology
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• v.64 no.4
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• pp.800-811
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• 2022

The integration of metabolomics and transcriptomics may elucidate the correlation between the genotypic and phenotypic patterns in organisms. In equine physiology, various metabolite levels vary during exercise, which may be correlated with a modified gene expression pattern of related genes. Integrated metabolomic and transcriptomic studies in horses have not been conducted to date. The objective of this study was to detect the effect of moderate exercise on the metabolomic and transcriptomic levels in horses. In this study, using nuclear magnetic resonance (NMR) spectroscopy, we analyzed the concentrations of metabolites in muscle and plasma; we also determined the gene expression patterns of branched chain (alpha) keto acid dehydrogenase kinase complex (BCKDK), which encodes the key regulatory enzymes in branched-chain amino acid (BCAA) catabolism, in two breeds of horses, Thoroughbred and Jeju, at different time intervals. The concentrations of metabolites in muscle and plasma were measured by ¹H NMR (nuclear magnetic resonance) spectroscopy, and the relative metabolite levels before and after exercise in the two samples were compared. Subsequently, multivariate data analysis based on the metabolic profiles was performed using orthogonal partial least square discriminant analysis (OPLS-DA), and variable important plots and t-test were used for basic statistical analysis. The stress-induced expression patterns of BCKDK genes in horse muscle-derived cells were examined using quantitative reverse transcription polymerase chain reaction (qPCR) to gain insight into the role of transcript in response to exercise stress. In this study, we found higher concentrations of aspartate, leucine, isoleucine, and lysine in the skeletal muscle of Jeju horses than in Thoroughbred horses. In plasma, compared with Jeju horses, Thoroughbred horses had higher levels of alanine and methionine before exercise; whereas post-exercise, lysine levels were increased. Gene expression analysis revealed a decreased expression level of BCKDK in the post-exercise period in Thoroughbred horses.

• Macromolecular Research
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• v.13 no.2
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• pp.141-146
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• 2005

Calix[4]crown-6-2,4-bis(4-aminobutyl ether), which has a crown-6 moiety at the 1,3-position and amino function at the 2,4-position, was prepared as an intermediate for the subsequent synthesis of calix[4]crown-6-containing polyamide and polyimide using adipoyl chloride and 1,2,4,5-benzenetetracarboxylic dianhydride. The chemical structures were characterized by IR, $^{1}H NMR$ spectroscopy and elemental analysis, and some of their physical properties, including their thermal behavior, were examined. The ion binding characteristics of the monomer and polymers for alkali metal and alkali earth metal ions were measured by liquid-liquid extraction from the aqueous phase into the organic phase. It has been observed that polyamide has a high binding ability towards various metal cations as compared to polyimide, which showed cesium ion selectivity.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.850-853
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• 2006

Four bent-core compounds were synthesized introducing ester linking group into mesogenic unit, varying the central unit with 1,6-, 1,7-, 2,3-, and 2,7-naphthylenes, and placing the dodecyloxy group in the terminal flexible unit. The structures of four compounds were identified by FT-IR and $^1H$ NMR spectroscopy, and the results were in accordance with expected molecular formula. The mesomorphic properties were investigated by differential scanning calorimetry and polarizing optical microscopy.

• Journal of Pharmaceutical Investigation
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• v.40 no.4
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• pp.219-223
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• 2010

The hyaluronic acid (HA) conjugate bearing $\alpha$-cyclodextrin ($\alpha$-CD) was synthesized as the potential carrier of poly(ethylene glycol) (PEG)-drug conjugates. The HA conjugate was prepared by the reaction between the carboxylic acid of HA and the primary amine of $\alpha$-CD in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and 1-hydroxybenzotriazole. The chemical structure of the conjugate was confirmed using $^1H$ NMR and FT-IR spectroscopy. The conjugate could form nano-sized particles in the presence of PEG by forming the inclusion complexes between $\alpha$-CD at the backbone of HA, which was demonstrated using electrophoretic light scattering and field emission transmission electron microscopy. It is anticipated that this novel kind of nanoparticles can serve as a useful delivery system for PEGylated drugs.

• Archives of Pharmacal Research
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• v.27 no.10
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• pp.1029-1033
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• 2004

From the methanol extract of the whole plants of Carpesium macrocephalum $F_R$. et $S_{AV}$., five sesquiterpene lactones (1: carabron, 2: tomentosin, 3: ivalin, 4: 4H-tomentosin, 5: carabrol) and three terpenoids (6: loliolide, 7: vomifoliol, 8: citrusin C) were isolated. The structures and stereochemistry of compounds 1-8 were established on the basis of chemical analysis as well as 1D- and 2D-NMR spectroscopy. Among them, compounds 2, 4, and 6-8 were isolated for the first time from Carpesium species.

• Journal of the Korean Magnetic Resonance Society
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• v.19 no.1
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• pp.42-48
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• 2015

The mannitol transporter Enzyme $II^{Mtl}$ of the bacterial phosphotransferase system has two cytoplasmic phosphoryl transfer domains $IIA^{Mtl}$ and $IIB^{Mtl}$. The two domains are linked by a flexible peptide linker in mesophilic bacterial strains, whereas they are expressed as separated domains in thermophilic strains. Here, we carried out backbone assignment of $IIA^{Mtl}$ from thermophilic Thermoanaerobacter Tencongensis using a suite of heteronuclear triple resonance NMR spectroscopy. We have completed 94% of the backbone assignment, and obtained secondary structural information based on torsion angles derived from the chemical shifts. $IIA^{Mtl}$ of Thermoanaerobacter Tencongensis is predicted to have six ${\beta}$ strands and six ${\alpha}$ helices, which is analogous to $IIA^{Mtl}$ of Escherichia coli.

• Journal of the Korean Chemical Society
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• v.39 no.5
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• pp.393-398
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• 1995

The oxo-nitrosyl complexes (n-Bu4N)2[M4O12Mo(NO)2{RC(NH2)NHO}2{RC(NH)NO}2] (M=Mo, W; R=(CH3)2CH, n-CH3CH2CH2) have been prepared by the reactions of monomeric complex containing {Mo(NO)2}2+ and polyoxometalates with isobutyl- and n-butylamidoxime. The prepared complexes were characterized by elemental analysis, infrared, 1H NMR, 13C NMR and UV-visible spectroscopy. These complexes contain two {M2O5}2+ [M=Mo, W] cores and a central {Mo(NO)2}2+ core. The {Mo(NO)2}2+ unit was the formally cis type and C2v symmetry in geometric structure. The two {M2O5}2+ cores and a central {Mo(NO)2}2+ core were not nearly interacted with electronic localization, which were identified by spectroscopy.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.200-200
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• 2017

Salinity stress is one of the most important abiotic stresses and severely impairs plant growth and production. Root is the first site for nutrient accumulation like as $Na^+$ in the plant. To investigate the response of wheat root under salinity stress, we executed the characterization of morphology and analysis of metabolites. Wheat seeds cv. Keumgang (Korean cultivar) were grown on the moist filter paper in Petri dish. After 5 days, seedlings were transferred to hydroponic apparatus at 1500 LUX light intensity, at $20^{\circ}C$ with 70% relative humidity in a growth chamber. Seedlings (5-day-old) were exposed to 50mM, 75mM, 100mM NaCl for 5 days. Ten-day-old seedlings were used for morphological characterization and metabolite analysis. Root and leaf length became shorter in high NaCl concentration compared to following NaCl treatment. For confirmation of salt accumulation, wheat roots were stained with $CoroNa^+$ Green AM, and fluoresce, and the image was taken by confocal microscopy. $Na^+$ ion accumulation rate was higher at 100mM compared to the untreated sample. Furthermore, to analyze metabolites in the wheat root, samples were extracted by $D_2O$ solvent, and extracted sample was analyzed by 1H NMR spectroscopy. Fourteen metabolites were identified in wheat roots using NMR spectroscopy. Methanol and ethanol were up-regulated, whereas formate, aspartate, aminobutyrate, acetate and valine were down-regulated under salinity stress on roots of wheat. Fumarate had no change, while glucose, betaine, choline, glutamate and lactate were unevenly affected during salinity stress.