• Journal of the Korean Chemical Society
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• v.33 no.1
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• pp.55-64
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• 1989

Reduction and equilibrium of vanadium-DTPA (DTPA = diethylenetriaminepentaacetic acid, $H_5A$) complexes at mercury electrodes are studied in 0.5M $NaClO_4$ aqueous solution at 3.2 < pH < 10.5 and 25$^{\circ}$C. At 3.2 < pH < 5.9, the reduction reaction is $V{\cdot}A^{2-}+H^-+e^-=V{\cdot}HA^{2-}$, while at 5.9 < pH < 10.5 it is $V{\cdot}A^{2-}+H^-+e^-=V{\cdot}A^{3-}$. The stability constants of $V{\cdot}HA^{2-}$ and $V{\cdot}A^{3-}$ are found to be $6.46{\times}10^{9}$ and $3.09{\times}10^{14}$, respectively. V(IV)-DTPA undergoes stepwise complexation as $VO^{2+}+H_2A^{3-}=VO{\cdot}HA^{2+}H^{+}$ and $VO{\cdot}HA^{2-}=VO{\cdot}A^{3+}+H$, where acidity constant of $VO{\cdot}HA^{2-}$- is pKa = 7.15. Stability constants of $VO{\cdot}HA^{2-}$ and $VO{\cdot}A^{3-}$ are found to be $1.41{\times}10^{14}$ and $3.80{\times}10^{17}$, respectively. It is detected that $VO^{2+}-DATA$ is reduced irreversibly to $VO^{2-}$ with the transfer coefficient of $\alpha$ = 0.43. At more cathodic overpotential, the reduction is stepwise as V(IV)${\to}$V(III)${\to}$V(II). The first one corresponds to $VO{\cdot}HA^{2-}+e^{-}{\to}VO{\cdot}HA{3+}$ at 3.2 < pH < 7.2 and $VO{\cdot}A^{3-}+e^{-}{\to}VO{\cdot}A^{4-}$ at 7.2 < pH < 10.5. The second is identical to that of V(III). Diffusion coefficients of $VO{\cdot}HA^{2-}$ and $VO{\cdot}A^{3-}$ are found to be $(9.0{\pm}0.3){\times}10^{-6}cm^2/s$ and $(5.9{\pm}0.4){\times}10^{-6}cm^2/ses$, respectively.

• Journal of Life Science
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• v.26 no.11
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• pp.1253-1258
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• 2016

Although major advances have been achieved in our understanding and treatment of diseases in many areas of medicine, relatively few improvements have been made in the area of gastrointestinal (GI) motor function. The dried root of Codonopsis pilosula (Franch.) Nannf. (CP) has been used as a traditional folk medicine for improving poor GI function in East Asia, including China and Korea. In the present study, neither aqueous (CP-W) nor ethanolic (CP-E) extracts of CP showed significant toxicity, even at an oral dose of 5 g/kg to mice. The effects of CP-W and CP-E on GI motor function were investigated by measuring in vivo the gastric emptying rate (GER) and intestinal transit rate (ITR) in mice. In normal mice, the ITR was significantly increased by CP-W in a dose-dependent manner, whereas the GER was not significantly affected by any CP extracts. The ITR was significantly retarded in the mice with experimental GI motility dysfunction (i.e., peritoneal irritation by acetic acid) compared with that in normal mice. However, the retardation was significantly recovered by the pre-treatment of CP-W in a dose-dependent manner. The above results suggest that CP-W might be a potential prokinetic agent preventing or alleviating GI motility dysfunctions in human patients.

• Journal of the Korea Organic Resources Recycling Association
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• v.23 no.3
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• pp.60-67
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• 2015

Objective of this study was to investigate adsorption characteristics of $PO_4-P$ to biochar produced from oak tree in respective to reduce eutrophication from runoff water in the cropland. For adsorption experiment, input amount of biochar was varied from 4 to 20 g/L with 30 mg/L $PO_4-P$ solution. Adsorption amounts and removal rates of $PO_4-P$ was increased at 3 times in 4~14 g/L, and increased at 28.6% in 4~16 g/L, respectively. The maximum adsorption amount ($q_m$) and binding strength constant(b) were calculated as 0.10 mg/g and 0.06 L/mg, respectively. The sorption of $PO_4-P$ to biochar was fitted well by Langmuir model because it was observed that dimensionless constant($R_L$) was 0.37. It was indicated that biochar is favorably adsorbed $PO_4-P$ because this value lie within 0 < $R_L$ < 1. Therefore, biochar produced from oak tree could be used as adsorbent for reduce eutrophication from runoff water in the cropland.

• Journal of the Korean Applied Science and Technology
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• v.22 no.1
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• pp.28-34
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• 2005

The structure of a carbon monoxide sorption complex of dehydrated fully $Ca^{2+}$-exchanged zeolite X, $|Ca_{46}(CO)_{27}|[Si_{100}Al_{92}O_{384}]$-FAU, has been determined in the cubic space group $Fd\;{\overline{3}}$ at $21^{\circ}C$ (a = 24.970(4) ) by single-crystal X-ray diffraction techniques. The crystal was prepared by ion exchange in a flowing stream of 0.05 M aqueous ${Ca(NO_3)_2}$ for three days, followed by dehydration at $400^{\circ}C$ and $2{\times}10^{-6}$ Torr for two days, and exposure to 100 Torr of zeolitically dry carbon monoxide gas at $21^{\circ}C$. The structure was determined in this atmosphere and was refined, using the 356 reflections for which $F_o$ > $4{\sigma}(F_o)$, to the final error indices $R_1$ = 0.059 and $wR_2$ = 0.087. In this structure, $Ca^{2+}$ ions occupy three crystallographic sites. Sixteen $Ca^{2+}$ ions fill the octahedral site I at the centers of hexagonal prisms (Ca-O = 2.415(7) ${\AA}$). The remaining 30 $Ca^{2+}$ ions are found at two nonequivalent sites II (in the supercages) with occupancies of 3 and 27 ions. Each of these $Ca^{2+}$ ions coordinates to three framework oxygens, either at 2.276(10) or 2.298(8) ${\AA}$, respectively. Twenty-seven carbon monoxide molecules have been sorbed per unit cell, three per supercage. Each coordinates to one of the latter 16 site-II $Ca^{2+}$ ions: C-Ca = 2.72(8) ${\AA}$. The imprecisely determined N-C bond length, 1.26(14) ${\AA}$, differs insignificantly from that in carbon monoxide(g), 1.13 ${\AA}$.

• Journal of Pharmaceutical Investigation
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• v.39 no.6
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• pp.393-400
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• 2009

PHEA (hydroxyethyl-aspartamide)-mPEG (methoy-polyethyleneglycol)-$C_{16}$ (hexadecylamine)-ED (ethylenediamine) was prepared as a drug delivery carrier. The structure and molecular weight of polymers were characterized by $^1H$-NMR and gel permeation chromatography. Micelle size and shape were measured by electro-photometer light scattering and transmission electron microscope. The mean diameter of micelles was 23 nm in aqueous solution. To evaluate the potential of these polymeric micelles as a drug carrier, PSI-mPEG-$C_{16}$-ED was conjugated with Cy5.5 for Near-Infrared Fluorescent (NIRF) based optical imaging. PSI-mPEG-$C_{16}$-ED-Cy5.5 was injected intravenously into mice (n=5) and in vivo NIRF imaging was performed during 48 h after injection. The biodistribution study at 24 h after injection showed the longcirculation property of PSI-mPEG-$C_{16}$-ED-Cy5.5. Therefore, PSI-mPEG-$C_{16}$-ED micelles could be a promising drug carrier and imaging agent.

• Journal of the Korean Chemical Society
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• v.39 no.5
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• pp.421-426
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• 1995

The hydrogels of hydrophilic three-dimensional methacrylate polymer networks were prepared from 2-hydroxyethyl methacrylate (HEMA) and ethylene glycol dimethacrylate (EDGMA) in aqueous solution. The interaction of water with the hydrophilic methacrylate polymers in the hydrogels was studied by pulse NMR spectroscopy. The spin-lattice relaxation times (T1) of low water content hydrogels showed the different double environments, resulting in two spin-lattice relaxation times (T1a and T1b). The values of T1a and T1b were 16.4${\times}$10-3 sec and 58.2${\times}$10-3 sec for a p(HEMA)-(10% H2O) system, and 13.2${\times}$10-3 sec and 23.1${\times}$10-3 sec for a crosslinked EGDMA-p(HEMA)-(10% H2O) system, respectively. The spin-spin relaxation times (T2) of the hydrogels were also measured as a function of water content in the p(HEMA)-(H2O)n and crosslinked EGDMA-p(HEMA)-(H2O)n system. The values of T2 were approximately 10 times less than those of T1 in agreement with the principles of spin relaxations.

• Journal of the Korean Ceramic Society
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• v.39 no.2
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• pp.178-183
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• 2002

Zinc fluosilicate ($ZnSiF_6$, 15% aqueous solution) was prepared using zinc oxide (ZnO) and fluosilicic acid ($H_2SiF_6$) by soluiton synthetic method. The fluidity and hydration properties of cement which was added $ZnSiF_6$ (aq.) as an additive for cement were studied. At water to cement ratio (W/C) equals to 0.45, the initial fluidity and slump loss of cement paste which the addition of $ZnSiF_6$ (aq.) was increased from 1.0% to 4.0% based on cement weight were investigated. Initial fluidity of cement paste was measured by mini-slump test and slump loss was examined by measuring the fluidity variation of cement paste with time elapsed from 0 min to 120 min at intervals 30 min. Also, the effect of $ZnSiF_6$ addition on the setting and hydration of cement paste when $ZnSiF_6$ increased in the addition range 1.0% to 3.0% were investigated. The fluidity of cement paste which was added 2.1% $ZnSiF_6$ (aq.) presented the highest value among all addition ranges. The setting time of cement paste was retarded gradually and the heat evolution of hydrated cement was reduced with the increasing of $ZnSiF_6$ addition.

• Journal of the Korean Chemical Society
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• v.16 no.5
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• pp.314-319
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• 1972

N-Methyl-p-aminophenol was polymerized by oxidative couplng in the aqueous iron chelate solution in the presence of oxygen, and black precipitate of oligo-(N-methyl-p-aminophenol) was formed quantitatively. In this oxidative polymerization reaction, methyl group attached to N in the monomer was partly eliminated, and it was clarified by the infrared spectra from the fact that the absorption of ${\delta}\;asym\;CH_3\;1460\;cm^{-1}$ and ${\delta}\;sym\;CH_3\;1380\;cm^{-1}$ in acetone insoluble fraction was much weaker than that in acetone soluble fraction. From Thermo-gravimetric analysis, oligo-(N-methyl-p-aminophenol) showed about 40% weight loss at $600^{\circ}C$ and it was less heat-resistant than oligo (p-aminophenol) that methyl group was not contained. In pyrolysis of oligo-(N-methyl-p-aminophenol) in He atmosphere, monomer N-methyl-p-aminophenol and water were formed, and in the pyrolytic gases, $H_2,\;CO,\;CO_2$ were detected by gas chromatography. From the above facts, to the structural change on oligo-(N-methyl-p-aminophenol) when it was heat-treated, it was considered that original linear structure was partly degraded, and the most of the oligomer was to go in with melt polycondensation to form polymer, and heat-resistant cyclic structure was formed at a time.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.7
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• pp.3519-3528
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• 2012

Inhibitory effects of Maclura amboinenesis Bl, one plant used traditionally for the treatment of cancers, on metastatic potential of highly metastatic B16F10 melanoma cells were investigated in vitro. Cell proliferation was assessed using the MTT colorimetric assay. Details of metastatic capabilities including invasion, migration and adhesion of B16F10 melanoma cells were examined by Boyden Chamber invasion and migration, scratch motility and cell attachment assays, respectively. The results demonstrated that n-hexane and chloroform extracts exhibited potent anti-proliferative effects (p<0.01), whereas the methanol and aqueous extracts had less pronounced effects after 24 h exposure. Bioactivity-guided chromatographic fractionation of both active n-hexane and chloroform extracts led to the isolation of two main prenylated xanthones and characterization as macluraxanthone and gerontoxanthone-I, respectively, their structures being identified by comparison with the spectral data. Interestingly, both exhibited potent effective effects. At non-toxic effective doses, n-hexane and chloroform extracts (10 and $30{\mu}g/ml$) as well as macluraxanthone and gerontoxanthone-I (3 and $10{\mu}M$) significantly inhibited B16F10 cell invasion, to a greater extent than $10{\mu}m$ doxorubicin, while reducing migration of cancer cells without cellular cytotoxicity. Moreover, exposure of B16F10 melanoma cells to high concentrations of chloroform ($30{\mu}g/ml$) and geratoxanthone-I ($20{\mu}M$) for 24 h resulted in delayed adhesion and retarded colonization. As insights into mechanisms of action, typical morphological changes of apoptotic cells e.g. membrane blebbing, chromatin condensation, nuclear fragmentation, apoptotic bodies and loss of adhesion as well as cell cycle arrest in the G1 phase with increase of sub-G1 cell proportions, detected by Hoechst 33342 staining and flow cytometry were observed, suggesting DNA damage and subsequent apoptotic cell death. Taken together, our findings indicate for the first time that active n-hexane and chloroform extracts as well as macluraxanthone and gerontoxanthone-I isolated from Maclura amboinensis Bl. roots affect multistep of cancer metastasis processes including proliferation, adhesion, invasion and migration, possibly through induction of apoptosis of highly metastatic B16F10 melanoma cells. Based on these data, M. amboinensis Bl. represents a potential candidate novel chemopreventive and/or chemotherapeutic agent. Additionally, they also support its ethno-medicinal usage for cancer prevention and/or chemotherapy.

• Journal of Korean Society of Forest Science
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• v.95 no.4
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• pp.429-434
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• 2006

The dried needles (1.5 kg) of Picea abies Karsten were ground, extracted with acetone-$H_2O$ (7:3, v/v), concentrated, and fractionated with a series of n-hexane, methylene chloride, ethyl acetate and water on a separatory funnel. Each fraction was freeze dried, then a portion of ethyl acetate soluble powder was chromatographed on a Sephadex LH-20 column using a series of aqueous methanol and ethanol-n-hexane mixture as eluents. The isolated compounds were identified by cellulose TLC, $^1H$-, $^{13}C$-NMR, FAB and EI-MS. (+)-catechin (compound I), (-)-epicatechin (compound II), kaempferol-3-O-${\beta}$-D-glucopyranoside (compound III), 4-hydroxyacetophenone (compound IV) were isolated from the ethyl acetate soluble fraction and (+)-catechin (compound I), protocatechuic acid (compound V) were isolated from the $H_2O$ soluble fraction of P. abies needle. The antioxidative activities of each fraction and the isolated compounds were tested by DPPH radical scavenging method, and EtOAc soluble fraction, (+)-catechin and (-)-epicatechin showed similar values to ${\alpha}$-tocopherol and BHT as controls.