• Transactions of the Korean hydrogen and new energy society
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• v.27 no.6
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• pp.660-669
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• 2016

A fluorinated-sulfonated, hydrophobic-hydrophilic copolymer was planed subsequently synthesized using typical nucleophilic substitution polycondensation reaction. A novel AB and ABA (or BAB) block copolymers were synthesized using sBCPSBP (sulfonated 4,4'-bis[4-chlorophenyl)sulfonyl]-1,1'-biphenyl), DHN (1,5-dihydroxynaphthalene), DFBP (decafluorobiphenyl) and HFIP (4,4'-hexafluoroisopropylidenediphenol). All block copolymers were easily cast and made into clear films. The structure and synthesized copolymers and corresponding membranes were analyzed using GPC (gel permeation chromatography), $^1H$-NMR ($^1H$ nuclear magnetic resonance) and FT-IR (Fourier transform infrared). TGA (Thermogravimetric analysis) and DSC (differential scanning calorimetry) analysis showed that the prepared membranes were thermally stable, so that elevated temperature fuel cell operation would be possible. Hydrophobic/hydrophilic phase separation and clear ionic aggregate block morpology was confirmed in both triblock and diblock copolymer in AFM (atomic force microscopy), which may be highly related to their proton transport ability. A sulfonated BAB triblock copolymer membrane with an ion-exchange capacity (IEC) of 0.6 meq/g has a maximum ion conductivity of 40.3 mS/cm at $90^{\circ}C$ and 100% relative humidity.

• Journal of IKEEE
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• v.21 no.3
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• pp.320-330
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• 2017

Porous nanosilica (PNS) has been identified as a potential candidate for controlled drug delivery. However, unmodified PNS-based carriers exhibited an initial release of loaded bioactive agents, which may limit their potential clinical applications. In this study, the surface of PNS was functionalized with adamantylamine (ADA) via disulfide bonds (-S-S-), PNS-S-S-ADA, which was then modified with cyclodextrin (CD)-heparin (Hep) (CD-Hep), PNS-S-S-CDH, for redox triggered rhodamine B (RhB) delivery. The obtained samples were then characterized by proton nuclear magnetic resonance ($^{1}H\;NMR$), Fourier transform infrared (FTIR), and transmission electron microscope (TEM). These results showed that PNS-S-S-CDH was successfully formed with spherical shape and average diameter of $45.64{\pm}2.33nm$. In addition, RhB was relatively encapsulated in the PNS-S-S-CDH (RhB@PNS-S-S-CDH) and slowly released up to 3 days. The release of RhB, in particular, was triggered due to the cleavage of -S-S- in the presence of dithiothreitol (DTT). It might be anticipated that the modified PNS can be used as redox-responsive drug delivery system in cancer therapy.

• Proceedings of the Ginseng society Conference
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• 1988.08a
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• pp.33-35
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• 1988

During a series of studies aimed at isolation of the tumor growth inhibitory substance from Panax ginseng. we found a new type of antitumor substance. The substance was isolated from a powder of the root of Panax ginseng C.A. Meyer. which is commonly used for various diseases as a commercial medical drug by the name of Korean Red Ginseng Powder in Japan. Data from infrared spectra proton and carbon-13 nuclear magnetic resonance. and high resolution mass spectra were identical with those of panaxytriol. Panaxytriol isolated from Korean Red Ginseng Powder (Nikkan Korai Ninjin Co.. Ltd.. Japan) inhibited the growth of several kinds of human and murine malignant cells in vitro. Although the detailed mechanism of cell growth inhibition by panaxytriol is yet to he elucidated. panaxytriol's action appeares to be more dose-dependent than time-dependent.

• Elastomers and Composites
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• v.54 no.1
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• pp.14-21
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• 2019

Main-chain/side-chain liquid crystalline polymers (MCSCLCPs) combined with an azobenzene group and a cholesteryl group were synthesized to impart light and temperature sensitivity to the polymer. The polymers were designed with the azobenzene unit as the mesogenic group of the main-chain and various compositions of the azobenzene and cholesteryl units as the mesogenic group of the side-chain. The chemical structures and physical properties of the synthesized polymers were investigated by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, differential scanning calorimetry, thermogravimetric analysis, polarized optical microscopy, and ultraviolet-visible (UV-Vis) spectroscopy. All the MCSCLCPs were amorphous and exhibited enantiotropic liquid crystal phases; these polymers achieved the nematic phase with increasing content of the azobenzene group and exhibited the cholesteric phase with weak liquid crystallinity as the content of the cholesteryl group was increased. Furthermore, the polymers containing the azobenzene group showed photoisomerization when exposed to UV-Vis light, and the CP-A3C7 and CP-A5C5 polymers exhibited thermochromism in the temperature range of the liquid crystal phase.

• Analytical Science and Technology
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• v.34 no.1
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• pp.9-16
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• 2021

In the group of commonly prescribed β-blocker drugs, one of the enantiomers is generally relatively more active than the others. This study aims to develop a technique for the chiral analysis of select β-blockers based on proton nuclear magnetic resonance (1H-NMR) spectrometry. (S)-2-Tert-butyl-2-methyl-1,3-benzodioxole-4-carboxylic acid ((S)-TBMB) was synthesized and utilized as a chiral derivatizing agent. Pure β-blocker enantiomers were isolated from racemates by semi-preparative liquid chromatography prior to derivatization. The reaction time and concentration of (S)-TBMB were controlled to improve the derivatization procedure. No racemization was found during the analysis. High-performance liquid chromatography (HPLC) analysis was also performed for comparative purposes. High agreement between the NMR and HPLC methods was achieved in the determination of (R)-metoprolol in a standard solution of the (S) isomer.

• Journal of the Korean Chemical Society
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• v.28 no.5
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• pp.335-341
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• 1984

Acetals of ${\alpha},{\beta}$-unsaturated aldehydes reacted readily with aryl bromides in the presence of palladium catalyst and triethylamine to form aryl conjugated enals. Acrolein diethyl acetal and methacrolein diethyl acetal were reacted with phenyl bromides with substituents such as methyl and isopropyl groups at $100^{\circ}C$. The reaction products yields except the reaction of o-bromotoluene with methacrolein diethyl acetal. The products were identified by proton nuclear magnetic resonance and infrared spectroscopy. In the reverse combination of reactants to prepare aliphatic 2,4-dienals in good yield of above 50%, 3-bromopropenal dimethyl acetal and (E)-3-bromo-2-methylpropenal diethyl acetal were used as vinylic halide reactants and 1-alkenes and ethyl acrylate as olefin reactants.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.1
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• pp.38-49
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• 1985

The water soluble organic fractions (WSOF) from an agricultural soil (W), a soil treated with sludge for 6 years ($WS_6$), a sludge-soil mixture incubated for one week ($WS_1$), and sewage sludge (SS) were extracted, purified, and characterized by elemental analysis, functional group determinations, infrared, UV-visible, and proton nuclear magnetic resonance spectrosocpy. The SS was characterized by higher organic H, N, and P contents, a higher H/C ratio, and a lower C/N ratio than W. Total acidity carboxyl and phenolic hydroxyl group contents were generally highest in SS, intermediate in $WS_6$ and $WS_1$, and lowest in W. Overall aromatic character and aromatic carboxyl group contents were highest in W, and lowest in SS. Aliphatic proton, aliphatic carboxyl, and phenolic hydroxyl group contents were highest in SS, and lowest in W. Protein decomposition products were the pronounced components in SS, and decreased in concentration as the sludge component in the mixtures decreased. The $^1H$-NMR spectra suggested that the SS-protons were bound to a wider range of functional groups than W-protons. Structural complexities around the aromatic protons followed the following order: SS>$WS_1$>$WS_6$>W.

• Journal of Applied Biological Chemistry
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• v.57 no.4
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• pp.347-352
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• 2014

The roots of Pueraria mirifica were extracted with 70% aqueous ethyl alcohol and partitioned into ethyl acetate (EtOAc), n-butyl alcohol (BuOH), and $H_2O$ fractions, successively. From the EtOAc fraction, four norsesquiterpenes were isolated through the repeated silica gel, octadecyl silica gel and Sephadex LH-20 column chromatographies. On the basis of physicochemical and spectroscopic data including nuclear magnetic resonance (NMR), mass spectrometry, and infrared spectroscopy, the chemical structures were identified as megastigm-5-en-3,9-diol (1), linarionoside B (2), 3,5,6,9-tetrahydroxymegastigm-7-ene (3) and 3,4,9-trihydroxymegastigma-5,7-diene (4). Especially, the configuration of the anomer hydroxyl group was determined as a from the coupling constants of the anomer proton (J =8.0 Hz) in the $^1H$-NMR spectrum. These compounds were isolated for the first time from the roots of P. mirifica in this study.

• Elastomers and Composites
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• v.52 no.3
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• pp.180-186
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• 2017

In this work, the effect of low-temperature dehydration of a poly(styrene-co-styrenesulfonic acid) (PSSA) membrane was investigated by differential scanning calorimetry, fourier transform infrared spectroscopy (FT-IR), electron magnetic resonancespectroscopy (EMR), and $^1H$- and $^{13}C$ solid-state nuclear magnetic resonance spectroscopy. These analyses were performed at room temperature for powdered PSSA specimens with and without dehydration and the following key observations were made. First, FT-IR analysis showed that low-temperature dehydration not only transformed the [${SO_3}^-{\cdots}H^+$] ionic pair in the non-hydrated PSSA to an $SO_3H$ group, but also induced the formation of -C=C- double bonds in the dehydrated PSSA. Second, the ${-SO_3}^{\bullet}$ radical was unambiguously identified by EMR spectroscopy. Third, H-abstraction was detected by $^1H$ magic-angle spinning spectroscopy. Finally, an unexpected color shift from white for the non-hydrated PSSA to a yellowish brown for the dehydrated sample was observed. In order to explain these experimental results, it was proposed that the formation of the intermediate hydrogen ($H^{\bullet}$) or hydroxyl radical ($HO^{\bullet}$) species was initiated by the dehydration process. The sespecies attacked the $SO_3H$ group and the tertiary proton at the ${\alpha}-carbon$, resulting in the formation of $-SO^{\bullet}$ radicals and -C=C- double bonds, which correlated with the color shift in the dehydrated PSSA sample. The semechanisms are useful for understanding the simultaneous loss of an aromatic ring and -SO- groups in the PSSA fuel cell membrane.

• Investigative Magnetic Resonance Imaging
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• v.3 no.2
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• pp.159-166
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• 1999

Purpose : To evaluate the effect of rotational correlation time (${\tau}_R$) and the possible related changes of other parameters, ${\tau}_M,{\;}{\tau}_S,{\;}and{\;}(\tau}_V$ of gadolinium (Gd) chelate on T1 relaxation enhancement in two pool model. Materials and Methods : The NMRD (Nuclear Magnetic Relaxation Dispersion) profiles were simulated from 0.02 MHz to 800 MHz proton Larmor frequency for different values of rotational correlation times based on Solomon-Bloembergen equation for inner-sphere relaxation enhancement. To include both unbound pool (pool A) and bound pool (pool B), the relaxivity was divided by contribution from unbound pool and bound pool. The rotational correlation time for pool A was fixed at the value of 0.1 ns, which is a typical value for low molecular weight complexes such as Gd-DTPA in solution and ${\tau}_R$ for pool B was changed from 0.1 ns to 20 ns to allow the slower rotation by binding to macromolecule. The fractional factor of was also adjusted from 0 to 1.0 to simulate different binding ratios to macromolecule. Since the binding of Gd-chelate to macromolecule cab alter the electronic environment of Gd ion and also the degree of bulk water access to hydration site of Gd-chelate, the effects of these parameters were also included. Results : The result shows that low field profiles, ranged from 0.02 to 40 MHz, and dominated by contribution from bound pool, which is bound to macromolecule regardless of binding ratios. In addition, as more Gd-chelate bound to macromolecule, sharp increase of relaxivity at higher field occurs. The NMRD profiles for different values of ${\tau}_S$ show the enormous increase of low field profile whereas relaxivity at high field is not affected by ${\tau}_S$. On the other hand, the change in ${\tau}$V does not affect low field profile but strongly in fluences on both inflection fie이 and the maximum relaxivity value. The results shows a fluences on both inflection field and the maximum relaxivity value. The results shows a parabolic dependence of relaxivity on ${\tau}_M$. Conclusion : Binding of Gd-chelate to a macromolecule causes slower rotational tumbling of Gd-chelate and would result in relaxation enhancement, especially in clinical imaging field. However, binding to macromolecule can change water enchange rate (${\tau}_M$) and electronic relaxation ($T_le$) vis structural deformation of electron environment and the access of bulk water to hydration site of metal-chelate. The clinical utilities of Gd-chelate bound to macromolecule are the less dose requirement, the tissue specificity, and the better perfusion and intravascular agents.