• Analytical Science and Technology
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• v.5 no.1
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• pp.41-49
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• 1992

An attempt was made to prepare two series of tetrakis eight-coordinate tungsten(IV) and cerium(IV) complexes containing the 5,7-dichloro-8-quinolinol(N:${\pi}$-acceptor atom, O:${\pi}$-donor atom) ligand. Tetrakis eight-coordinate tungsten(IV) complex of 2-mercaptopyrimidine(N:${\pi}$-acceptor atom, S:${\pi}$-donor atom) ligand have also been prepared. And the new series of mixed-ligand eight-coordinate tungsten(IV) complexes containing bidentate ligands 5,7-dichloro-8-quinolinol and 2-mercaptopyrimidine have been prepared, isolated by TLC and characterized. $W(dcq)_4$, $W(dcq)_3(mpd)_1$, $W(dcq)_2(mpd)_2$, $W(dcq)_1W(dcq)_3$ and $W(mpd)_4$ complexes of MLCT absorption band appeared to 710nm, 680nm, 625nm, 581nm, and 571nm(${\varepsilon}\;max={\sim}>{\times}10^4$) on low-energy respectively. The specific absorption wave length of $Ce(dcq)_4$ is appeared 520nm(${\varepsilon}\;max={\sim}>{\times}10^4$). The Chemical shift values by proton of coordinated position appeared to $W(dcq)_4$ [$H_2:8.9ppm$]; $W(dcq)_3(mpd)_1$ [$H_2:9.3$,$H_6:9.2ppm$]; $W(dcq)_2(mpd)_2$ [$H_2:9.7$,$H_6:8.95ppm$]; $W(dcq)_1(mpd)_3$ [$H_2:9.8$,$H_6:9.4ppm$]; $W(mpd)_4$ [$H_6:8.8ppm$]; $Ce(dcq)_4$ [$H_2:9.3ppm$] with $^1H$-NMR. The inertness of mixed-ligand eight coordinate tungsten(IV) complexes have been investigated by UV-Vis. spectroscopic method in dimethylsulfoxide at $90^{\circ}C$. The inertness of $W(dcq)_n(mpd)_{4-n}$ complexes showed the following order, $W(dcq)_3(mpd)_1;k_{obs.}=3.8{\times}10^{-6}$ > $W(mpd)_4;k_{obs.}=6.0{\times}10^{-6}$ > $W(dcq)_4;k_{obs.}=6.4{\times}10^{-6}$ > $W(dcq)_2(mpd)_2;k_{obs.}=7.0{\times}10^{-6}$ > $W(dcq)_1(mpd)_3;k_{obs.}=1.7{\times}10^{-5}$, which showed the inertness until 16days, 10days, 9days, 8days, and 4days. The $W(mpd)_4$ is very inert as $k_{obs.}=3.6{\times}10^{-6}$(16days) in xylene at $90^{\circ}C$ and $k_{obs.}=6.0{\times}10^{-6}$(10days) in DMSO at $90^{\circ}C$.

• Korean Journal of Ecology and Environment
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• v.34 no.1 s.93
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• pp.20-29
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• 2001

The amount, chemical composition and optical property of extracellular dissolved organic carbon (EOC) by phytoplankton were examined using axenic cultures of Microcystis aeruginosa, Anabaena flos-aquae, and Oscillatoria agardhii. The extracellular organic matter was categorized into five fractions (hydrophobic acids; AHSs, hydrophobic neutrals; HoNs, hydrophilic acids; HiAs, hydrophilic bases; HiBs, and hydrophilic neutrals; HiNs) using three adsorbent resins(XAD-8, cation, and anion). The release pattern and chemical composition of EOC varied with algal species and their growth phases. Percentage of extracellular release increased with age in all cultures. HiAs were the dominant component of EOC in all cultures, whereas the proportion of HiAs decreased with age in all cultures. In contrast, the proportions of HiBs and HiNs increased as cultures aged. In particular, the HiN fraction increased from 0% to 44% of EOC in M. aeruginosa and from 3.0% to 28% in A. flos-aquae, respectively. The proportion of AHSs was higher in the cultures of A. flos-aquae(7.5${\sim}$16%) and O. agardhii (8.7${\sim}$16%) than M. aeruginosa(0.2${\sim}$2.5%). The proportions of AHSs increased with culture age in M. aeruginosa and O. agardhii, but decreased in A. flos-aquae. The specific UV absorbance also varied among species; 1.9 Abs${\cdot}$cm$^{-1}$/mgC${\cdot}$L$^{-1}$ for M. aeruginosa, 3.7 Abs${\cdot}$cm$^{-1}$/mgC${\cdot}$L$^{-1}$ for A. flos-aquae, and 13.0 Abs${\cdot}$cm$^{-1}$/mgC${\cdot}$L^{-1}$ for O. agardhii. The results of this study indicates that DOC excreted by three blue-green algae differed with species and the growth phase.

• Korean Journal of Environmental Agriculture
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• v.5 no.1
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• pp.1-10
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• 1986

To investigate the effects of paper sludge on the seasonal variations of soil humus, paper sludges were applied to the pots at the rates of 600㎏/10a which was either preadjusted C/N ratio to 30 : 1 or not adjusted. The effects were compared with those of control. 1) The contents of ether soluble materials, resins, water soluble polysaccharides, hemicellulose, cellulose, ligno-protein, humic acid and fulvic acid were higher in the sludge treated soil than in the control, furthermore, the content of ligno-protein had positive correlation with that of organic nitrogen in soil. 2) Optical density of UV and visible spectra of humic acid obtained from all the treated soil was decreased with increasing wavelength. In functional groups of humic acid, phenolic-OH/alcoholic-OH ratio was slightly higher in the sludge treated soil than in the control. The types of humic acid in all treated soil were P and Rp types. 3) The infrared spectra of humic acid extracted from the soil were characterized by main absorption bands in the regions of $3, 400cm^{-1}$(H-bonded OH), $2,900cm^{-1}$ (aliphatic C-H stretching), $1,630cm^{-1}$ (aromatic C=C and/or H-bonded C=O) and $1,050cm^{-1}$ (Si-O of silicate impurity).

• Journal of the Society of Cosmetic Scientists of Korea
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• v.39 no.1
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• pp.1-8
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• 2013

In this work, comparative study on antioxidative activities of extracts from Glycyrrhiza uralensis (G. uralensis) produced in Korea and in China and Glycyrrhiza glabra (G. glabra) produced in Uzbekistan was conducted. Among three origins, 50% ethanol extracts (21.15 ${\mu}g/mL$), ethyl acetate fraction (29.15 ${\mu}g/mL$) and aglycone fraction (3.26 ${\mu}g/mL$) of G. uralensis from Korea showed the higher free radical (1,1-phenyl-2-picrylhydrazyl, DPPH) scavenging activity ($FSC_{50}$) than extracts from other origins. Reactive oxygen species (ROS) scavenging activities ($OSC_{50}$) of extracts from three origins on ROS generated in $Fe^{3+}-EDTA/H_2O_2$ system were investigated using luminol-dependent chemiluminescence assay 50% ethanol extract (1.00 ${\mu}g/mL$) and ethyl acetate fraction (0.34 ${\mu}g/mL$) of G. uralensis from China showed the most prominent ROS scavenging activity. The protective effects of extract/fractions of G. uralensis and G. glabra extracts on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. 50% ethanol extract and aglycone fraction of G. uralensis and G. glabra extracts from three origins showed cellular protective effects in a concentration dependent manner (5 ~ 50 ${\mu}g/mL$). Aglycone fraction of G. uralensis from Korea (${\tau}_{50}$ = 847.4 min)especially showed cellular protective effects four times higher than that from China (${\tau}_{50}$ = 194.3 min). These results indicate that G. uralensis and G. glabra extracts, which have been used as whitening agent, could be applicable to functional cosmetic ingredient as a natural antioxidant. Judging from the prominent cellular protecitve effects, it is concluded that G. uralensis and G. glabra extracts can protect the skin from $^1O_2$ and various ROS induced by UV.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.4
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• pp.391-402
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• 2014

In this study, the antioxidative effects and component analysis for the extracts of Rumex acetosa L. were investigated. All experiments were performed with 50% ethanol extract, ethyl acetate fraction and aglycone fraction obtained from dried R. acetosa L.. Free radical scavenging activities (1,1-diphenyl-2- picrylhydrazyl) size of, in the order of aglycone fraction > ethyl acetate fraction > 50% ethanol extract, aglycone fraction ($45.10{\mu}g/mL$) showed the highest radical scavenging activity. Reactive oxygen species (ROS) scavenging activity (total antioxidant capacity, $OSC_{50}$) on ROS generated in $Fe^{3+}-EDTA/H_2O_2$ system was also, in the order of ethyl acetate fraction> aglycone fraction> 50% ethyl acetate fraction, ethyl acetate fraction ($2.68{\mu}g/mL$) was shown a great antioxidant capacity. The total antioxidant capacity of the ethyl acetate fraction was found to be greater than L-ascorbic acid, known as a typical hydrophilic antioxidant ($6.88 {\mu}g/mL$). The cellular protective effects of R. acetosa L. extracts on the $^1O_2$-induced cellular damage of human erythrocytes were exhibited at all concentration-dependent ($1{\sim}25{\mu}g/mL$). Especially, aglycone fraction (${\tau}_{50}$, 104.80 min) in $25{\mu}g/mL$ showed the most protective effect among extracts. Components of the ethyl acetate fraction obtained from R. acetosa L. extracts were analyzed by TLC, HPLC chromatogram, LC/ESI-MS/MS. As a result, the ethyl acetate fraction contained several flavonoids, such as orientin, isoorientin, vitexin, isovitexin. These results indicate that the R. acetosa L. extracts can be used as antioxidants in biological systems, particularly skins exposed to UV radiation by quenching and/or scavenging $^1O_2$ and other ROS. Thus, the extracts of R. acetosa L. could be applicable to new anti-aging cosmeceutical ingredients.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.129-129
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• 2016

Graphene, as a single layer of $sp^2$-bonded carbon atoms packed into a 2D honeycomb crystal lattice, has attracted much attention due to its outstanding properties. In order to synthesize high quality graphene, transition metals, such as nickel and copper, have been widely employed as catalysts, which needs transfer to desired substrates for various applications. However, the transfer steps are not only complicated but also inevitably induce defects, impurities, wrinkles, and cracks of graphene. Furthermore, the direct synthesis of graphene on dielectric surfaces has still been a premature field for practical applications. Therefore, cost effective and concise methods for transfer-free graphene are essentially required for commercialization. Here, we report a facile transfer-free graphene synthesis method through nickel and carbon co-deposited layer. In order to fabricate 100 nm thick NiC layer on the top of $SiO_2/Si$ substrates, DC reactive magnetron sputtering was performed at a gas pressure of 2 mTorr with various Ar : $CH_4$ gas flow ratio and the 200 W DC input power was applied to a Ni target at room temperature. Then, the sample was annealed under 200 sccm Ar flow and pressure of 1 Torr at $1000^{\circ}C$ for 4 min employing a rapid thermal annealing (RTA) equipment. During the RTA process, the carbon atoms diffused through the NiC layer and deposited on both sides of the NiC layer to form graphene upon cooling. The remained NiC layer was removed by using a 0.5 M $FeCl_3$ aqueous solution, and graphene was then directly obtained on $SiO_2/Si$ without any transfer process. In order to confirm the quality of resulted graphene layer, Raman spectroscopy was implemented. Raman mapping revealed that the resulted graphene was at high quality with low degree of $sp^3$-type structural defects. Additionally, sheet resistance and transmittance of the produced graphene were analyzed by a four-point probe method and UV-vis spectroscopy, respectively. This facile non-transfer process would consequently facilitate the future graphene research and industrial applications.

• Journal of the Korean Applied Science and Technology
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• v.28 no.4
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• pp.482-490
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• 2011

In this study, the antioxidative effects and inhibitory effects on tyrosinase and elastase of Sorbus commixta (S. commixta) twig extracts were investigated. The aglycone fraction of S. commixta twig extract showed the prominent free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activity($FSC_{50}$, $13{\mu}g/mL$). Reactive oxygen species (ROS) scavenging activities of S. commixta twig extracts on ROS generated in $Fe^{3+}-EDTA/H_2O_2$ system were investigated by the luminol-dependent chemiluminescence assay. The 50 % ethanol extract among extracts showed the most prominent ROS scavenging activity ($OSC_{50}$, $0.189{\mu}g/mL$). The cellular protective effects of extract/fractions of S. commixta twig on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. The 50 % ethanol extract and ethyl acetate fraction showed the cellular protective effects against ROS in a concentration dependent manner ($5{\sim}50{\mu}g/mL$). The inhibitory effect of S. commixta twig extract on tyrosinase was investigated to assess the whitening efficacy. The ethyl acetate ($IC_{50}$, $113.2{\mu}g/mL$) and aglycone fraction($IC_{50}$, $105.3{\mu}g/mL$) on tyrosinase showed more remarkable inhibitory effect than arbutin($IC_{50}$, $226.88{\mu}g/mL$), known as the whitening agent. The inhibitory effect of aglycone fraction ($IC_{50}$, $6.9{\mu}g/mL$) on elastase was simillar to quercetin($IC_{50}$, $6.1{\mu}g/mL$), flavonoid known as reference compound. These results indicate that extract/fractions of S. commixta twig can function as antioxidants in biological systems, particularly skin exposed to UV radiation by scavenging $^1O_2$ and other ROS, and protect cellular membranes against ROS. S. commixta twig extracts can be applicable to new functional cosmetics for anti-aging products.

• Journal of Periodontal and Implant Science
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• v.24 no.3
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• pp.597-606
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• 1994

Oxygen derived radicals($O_2\;^-$, $H_2O_2$, and $OH^-$) are thought to play a role in a lot of human diseases. And it has been believed that antioxidant enzymes such as superoxide dismutase(SOD) and catalase could protect the tissues from damage resulting from the oxygen derived free radicals. The purpose of this study was performed to investigate the activity of the SOD(CuZn- and Mn-SOD) and catalase in inflammatory gingival tissues and the correlation between boold glucose level and antioxidants and age in non-insulin dependent diabetes mellitus(NI- DDM) patients. For this study, the patients were classified into normal, inflammatory, and diabetic, and ten their papillary bleeding index(PBI) and gingival index were checked. Subjects consisted of 11 healthy patients with no inflammatroy gingiva, 20 adult periodontitis patients, and 8 diabetic patients, aged 33 to 66(average: 44.62). The blood glucose level of diabetic group was ranged from 120ml/dl to 160ml/dl(physical status 0 : averge : 135.67ml/dl). Gingival tissues were surgically obtained from the patients during periodontal surgery, extraction, and clinical corwn lenghening procedure. The activity of CuZn and Mn- SOD and catalase in the gingival tissues was measured by using UV-spectrophotometer by the same methods that Crapo et al. And Aebi did, respectively. The results were as follows : 1. The Mn-SOD activity was significantly lower in inflammatory group in comparison to normal group(P<0.05), and the activities of antioxidants in diabetic group were not significant in comparison to normal inflammatory group(P>0.05). 2. The activities of antioxidants showed little variation among individuals of different ages (P>0.05). 3. The higher blood glucose level was, the higher gingival index was(P<0.05). 4. There was no correlation between blood glucoe level and activity of antioxidant in inflammatory gingival tissues of NIDDM patients(P>0.05). In conclusion, these results, within the limits of the present experiment, suggest that the activity of Mn-SOD might reflect the inflammatory status of gingival tissue, and the activity of antioxidants was independent of blood glucose level of diabetic patients in physical status 0.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.35 no.4
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• pp.293-300
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• 2009

In this study, we investigated the antioxidative activity and inhibitory effects on elastase and tyrosinase of Persicaria hydropiper L. extracts. The free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activities ($FSC_{50}$) of ethyl acetate fractions of Persicaria hydropiper L. was $5.23\;{\mu}g/mL$. Reactive oxygen species (ROS) scavenging activities ($OSC_{50}$) of some Persicaria hydropiper L. extracts on ROS generated in $Fe^{3+}$-EDTA/$H_2O_2$ system were investigated using the luminol - dependent chemiluminescence assay. The ROS scavenging activities ($OSC_{50}$) of ethyl acetate fractions of Persicaria hydropiper L. was $0.40\;{\mu}g/mL$. The protective effects of extract / fractions of Persicaria hydropiper L. on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. The Persicaria hydropiper L. extracts suppressed photohemolysis in a concentration dependent manner ($1\;{\sim}\;10\;{\mu}g/mL$). Inhibitory effects ($IC_{50}$) on tyrosinase of aglycone fraction of Persicaria hydropiper L. extracts was $8.90\;{\mu}g/mL$. Inhibitory effects ($IC_{50}$) on elastase of aglycone fraction of Persicaria hydropiper L. extracts was $2.37\;{\mu}g/mL$. These results indicate that extract / fractions of Persicaria hydropiper L. can function as antioxidants in biological systems, particularly skin exposed to UV radiation by anti-oxidative activity and protect cellular membranes against ROS. Persicaria hydropiper L. extract / fractions could be used as a new cosmeceutical for whitening and anti-wrinkle products.

• Journal of the Korean Chemical Society
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• v.55 no.4
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• pp.603-611
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• 2011

Ethoxylacetyl oxime ligands [HL, (1) and $H_2L^1$, (3)] react with copper(II) acetate monohydrate yield octahedral and square planar complexes, respectively. The complexes have been postulated due to elemental analyses, IR, UVVis. spectra, magnetic susceptibility, conductivity and ESR spectra. Molar conductance of the complexes in DMF indicates a non-ionic character. The ESR spectra of [$(L)_2Cu(H_2O)_2$], (2) complex at room temperature and 77K are characteristic of an axial symmetry ($d_{x2-y2}$) with covalent bond character and have a large line width typical of dipolar interactions. However, [$(L^1)Cu$], (4) complex in the solid state showed spectra of marked broadening and loss of hyperfine splitting confirming spinexchange interactions between the copper(II) sites. The spectrum of the doped copper(II) complex at room temperature showed super-hyperfine splitting from coordinated nitrogen atoms and it has an axial type ($d_{x2-y2}$) with covalent bond character and an essentially square-planar arrangement around the copper(II) ion. The spectrum of [$(L^1)Cu$], (4) in frozen methanol at 77K was characteristic of the triplet state of a dimer species and the distance found between the two copper(II) centers was calculated and is equal to 4.8 ${\AA}$.