• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.1
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• pp.23-28
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• 2011

Resveratrol has been associated with reduced cardiovascular disease and reduced cancer risk. This phytochemical has been reported in a number of plant species including grapes, peanuts and pine trees in response to stress such as fungal infection, heavy metal ions or UV irradiation. The objective of this study was to determine the resveratrol contents in leaves of mulberry varieties at different collecting times. Quantitative analysis of 16 cultivars showed a range of $102{\sim}466{\mu}g/100g$ on dry weight basis (which is equivalent to $25{\sim}116.5{\mu}g/100g$ on fresh weight basis). Resveratrol contents in mulberry leaves was higher in autumn than spring, and higher in fully matured leaves than in juvenile leaves. Among the tested samples, 'Kaeryangppong', 'Sugeppong' and 'Cheongilppong' collected in the middle of October showed high resveratrol contents of $838{\mu}g/100g$, $803{\mu}g/100g$, $800{\mu}g/100g$ on dry weight basis, respectively. Especially mulberry leaves dried in the shade showed of $1,030{\mu}g/100g$ on dry weight basis in resveratrol content, this result may contribute to utilization of mulberry leaves.

• Economic and Environmental Geology
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• v.35 no.4
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• pp.325-337
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• 2002

We examined the contamination of stream water and stream sediments by heavy metal elements with respect to distance from the abandoned Backun Au-Ag-Cu mine. High contents of heavy metals (Pb, Zn, Cu, Cd, Mn, and Fe) and aluminum in the waters connected with mining and associated deposits (dumps, tailings) reduce water quality. In the mining area, Ca and SO$_4$ are predominant cation and anion. The mining water is Ca-SO$_4$ type and is enriched in heavy metals resulted from the weathering of sulfide minerals. This mine drainage water is weakly acid or neutral (pH; 6.5-7.1) because of neutralizing effect by other alkali and alkaline earth elements. The effluent from the mine adit is also weakly acid or neutral, and contains elevated concentrations of most elements due to reactions with ore and gangue minerals in the deposit. The concentration of ions in the Backun mining water is high in the mine adit drainage water and steeply decreased award to down stream. Buffering process can be reasonably considered as a partial natural control of pollution, since the ion concentration becomes lower and the pH value becomes neutralized. In order to evaluate mobility and bioavailability of metals, sequential extraction was used for stream sediments into five operationally defined groups: exchangeable, bound to carbonates, bound to FeMn oxide, bound to organic matter, and residual. The residual fraction was the most abundant pool for Cu(2l-92%), Zn(28-89%) and Pb(23-94%). Almost sediments are low concentrated with Cd(2.7-52.8 mg/kg) than any other elements. But Cd dominate with non stable fraction (68-97%). Upper stream sediments are contaminated with Pb, and down area sediments are enriched with Zn. It is indicate high mobility of Zn and Cd.

• Analytical Science and Technology
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• v.6 no.1
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• pp.29-37
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• 1993

Some new podands containing phenyl(B), benzyl(Bz), pyridine(Py), quinoline(Q) and naphthalene(Np) as end-groups, and oxygen(O) and sulfur(S) in ether chains as donor atoms have been synthesized. The univalent cation binding characteristics of these podands have been studied by NMR titration and solvent extraction. By NMR titration we have found that the most of podands form 1:1 complexes with $Ag^+$ ion. Especially, the substituted sulfur atoms in ether chains show the effects to enhance the stabilities. We also carried out the extractions of univalent cation picrates including alkaline metal, $Ag^+$, $Tl^+$ and $NH_4{^-}$ ions from aqueous to chloroform layer by using these podands. We found that the extractabilities of $Ag^+$ ion with the quinoline-containing podands such as, $Q_2O_4$, $Q_2O_5$ and $BQO_5$ were 86.8, 86.6 and 48.0% respectively, but the naphthalene-containing podands such as, $Np_2O_4$ and $Np_2O_5$ extracted quite small amount. Otherwise, in cases of $Bz_2O_3S_2$(89.4%), $B_2O_2S_2$(96.8%), $B_2O_3S_2$(58.9%), $Py_2O_2S_2$(58.8%), $Py_2O_3S_2$(42.1%), and $B_2O_4S$(15.0%), interestingly, $Bz_2O_3S_2$ which have sulfur atoms and benzyl groups showed the highest extraction selectivity for $Ag^+$ ion. This result seems due to not only the strong interaction of $Ag^+$ ion with sulfur donors according to the HSAB theory, but also the effective ${\pi}-{\pi}$ stacking interaction between two aromatic end-groups which is enhanced by the flexible methylene spacing group in benzyl groups instead of phenyl groups. The extraction coefficients gave the similar tendency as the extractabilities and the stabilities. From these results, it could be concluded that the predominant factor affected to extraction coefficients is the stabilities, which are strongly influenced by the structures of podands.

• Journal of Life Science
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• v.25 no.5
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• pp.487-495
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• 2015

We carried out pH stability, chemical inhibition, chemical modification, and pH-dependent kinetic parameter assessments to further characterize protocatechuate 3,4-dioxygenase from Pseudomonas pseudoalcaligenes KF707. Protocatechuate 3,4-dioxygenase was stable in the pH range of 4.5~10.5. L-ascorbate and glutathione were competitive inhibitors with $K_{is}$ values of 0.17 mM and 0.86 mM, respectively. DL-dithiothreitol was a noncompetitive inhibitor with a $K_{is}$ value of 1.57 mM and a $K_{ii}$ value of 8.08 mM. Potassium cyanide, p-hydroxybenzoate, and sodium azide showed a noncompetitive inhibition pattern with $K_{is}$ values of 55.7 mM, 0.22 mM, and 15.64 mM, and $K_{ii}$ values of 94.1 mM, 8.08 mM, and 662.64 mM, respectively. $FeCl_{2}$ was the best competitive inhibitor with a $K_{is}$ value of $29{\mu}M$. $FeCl_{3}$, $MnCl_{2}$, $CoCl_{2}$, and $AlCl_{3}$ were also competitive inhibitors with $K_{is}$ values of 1.21 mM, 0.85 mM, 3.98 mM, and 0.21 mM, respectively. Other metal ions showed noncompetitive inhibition patterns. The pH-dependent kinetic parameter data showed that there may be at least two catalytic groups with pK values of 6.2 and 9.4 and two binding groups with pK values of 5.5 and 9.0. Lysine, cysteine, tyrosine, carboxyl, and histidine were modified by their own specific chemical modifiers, indicating that they are involved in substrate binding and catalysis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.5
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• pp.273-288
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• 1991

To elucidate the physiological and biochemical differences between chondrichthyes and osteichthyes, the properties of the specific digestive enzymes in cat-shark, Cephaloscyllium umbratile, and mackerel, Scomber japonicus, were studied. Homogenous trypsin proved through the disc-electrophoresis, SDS-PAG electrophoresis and gel filtration was obtained from the pancreas of cat-shark by $50-70\%$ saturated ammonium sulphate fractionation, DEAE-Sephadex A-50 column chromatography, benzamidine-Sepharose 6B affinity chromatography and Sephadex G-75-120 gel filtration. Two types of trypsins were also obtained from the pyloric caeca of mackerel by $30-70\%$ saturated ammonium sulphate fractionation and the slightly modified procedure from the method adopted in the purification of cat-shark trypsin. The two trypsins, designated trypsin A and B, were proved their homogeneity by disc- and SDS-PAG electrophoresis and gel filtration. The molecular weights of the trypsins were estimated to be 31,700 for cat-shark trypsin, 30,000 for mackerel trypsin A and 29,000 for mackerel trypsin B by SDS-PAG electrophoresis, but those were estimated to be 21,500 for cat-shark trypsin, 23,700 for mackerel trypsin A and 21,500 for mackerel trypsin B by gel filtration. The trypsins exhibited their optimum conditions at pH 9.0 and on temperature ranged from $45^{\circ}C\;to\;50^{\circ}C$ for cat-shark, and at pH 8.0 and a temperature of $50^{\circ}C$ for mackerel trypsin A and B, respectively. The cat-shark trypsin was stable at pH 10.0 and the temperature below $10^{\circ}C$, whereas the mackerel trypsin A and B, were stable in the range over pH 7.0 to pH 9.0 below $10^{\circ}C$ and at pH 8.0 below $35^{\circ}C$, respectively. The mackerel trypsins were severely inhibited by some heavy metal ions such as $Ag^{2+},\;Cu^{2+}\;and\;Hg^{2+}$ compared to cat-shark trypsin. All of the enzymes were also inhibited by antipain, leupeptin, TLCK(tosyllysine chloromethyl ketone) and SBTI(soybean trypsin inhibitor) remarkably. The inhibitory effects of PMSF(phenylmethane sulphonylfluoride), DFP(diisopropyl fluorophosphate) and benzamidine were indicated that these enzymes belong to serine-proteases.

• Clean Technology
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• v.24 no.1
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• pp.41-49
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• 2018

Y zeolites with different extra-framework cations, such as $Na^+$, $N^+$, $Ca^{2+}$, and $Cu^{2+}$, with different charge and ionic radius have been investigated to greatly enhance a working capacity (W) of $CO_2$ adsorption at $25^{\circ}C$ and a $CO_2/CO$ selectivity factor (S). A sample of NaY with a very small amount of 0.012% $Ca^{2+}$ was fully reversible for seven times repeated $CO_2$ adsorption/desorption cycles, thereby forming no surface carbonates unlikely earlier reports. Although at pressures above 4 bar, 2.00% CaY, 1.60% CuY and 1.87% LiY all showed a $CO_2$ adsorption very similar to that measured for NaY, they gave a significant decrease in the adsorption at lower pressures, depending on the metal ion. At 0.5 ~ 2.5 bar, the extent of $CO_2$ adsorption was in the order NaY > 1.60% CuY > 2.00% CaY > 1.87% LiY. All the $Na^+-based$ metals-exchanged zeolites have a FAU (faujasite) framework and a Si/Al value near 2.6; thus, there is no discernible difference in the framework topology, framework chemical compositions, effective aperture size, and channel structure between the zeolite samples. Therefore, the distinctive behavior in the adsorption of $CO_2$ with a character as a weak Lewis acid is associated with the site basicity of the zeolites, and the interaction potentials of the cations. Different trend was shown for a CO adsorption due to weaker quadrupole interactions. Adsorption of $CO_2$ and CO on samples of CaY with 0.012 to 5.23% Ca disclosed a significant dependence on the Ca loading. The $CO_2$ adsorption increased when the cation exists up to ca. 0.05%, while it decreased at higher Ca amounts. However, values for both W and S could greatly increase as the bare zeolite is enriched by $Ca^{2+}$ ions. The 5.23% CaY had $W=2.37mmol\;g^{-1}$ and S = 4.37, and the former value was comparable to a benchmark reported in the literature.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.1
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• pp.33-42
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• 2000

Adsorption onto the surfaces of solid particles is a well known phenomenon that causes the retardation effect of heavy metals in soils. For adequate remediation of soil and groundwater contamination, it is important to investigate the mobility of heavy metals that largely depends on pH conditions in the soil water since adsorption of heavy metals is pH-dependent. In this study, we investigated the transport of Zn ion under various pH conditions in a sandy soil by conducting batch and column tests. The batch test was performed using the standard procedure of equilibrating fine fractions collected from the soil with eleven different initial $ZnCl_2$ concentrations, and analysis of Zn ion in the equilibrated solutions using ICP-AES. The column test consisted of monitoring the concentrations of soil solutions exiting the soil column with time known as a breakthrough curve (BTC). We injected respectively $ZnCl_2$ and KCl solutions with the concentration of 10 g/L as a tracer in a square pulse type under three different pH conditions (7.7, 5.8, 4.1) and monitored the flux concentration at the exit boundary using an EC meter and ICP-AES. The resident concentration was also monitored at the 10cm-depth by Time Domain Reflectometry (TDR). The results of batch test showed that ion exchange process between Zn and other cations (Ca, Mg) was predominant. The retardation coefficients obtained from adsorption isotherms (Linear, Freundlich, Langmuir) resulted in the various values ranging from 1.2 to 614.1. No retardation effect but ion exchange was found for the BTCs under all pH conditions. This can be explained by the absence of other cations to desorb Zn ion from soil exchange sites under the conditions of ETC experiment imposing blank water as leachate in steady-state flow. As pH decreased, the peak concentration of Zn increased due to the competition of Zn with hydrogen ions ($H^+$) and the concentrations of other cations decreased. The peak concentration of Zn was increased by 12.7 times as pH decreased from 7.7 to 4.1.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.1
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• pp.42-50
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• 2009

Samples of subway dust were collected by the air filter system of 30 subway stations on Daegu subway line 1 in January 2008. Samples were sieved below 100 ${\mu}m$, and 14 elements were analyzed using ICP after acid extraction. Results obtained from the source assessment of trace elements using enrichment factor showed that Ca, Fe, K, Mg, Mn, Na, V were influenced by natural sources such as weathered rock and resuspended soil, while Cd, Cr, Cu, Ni, Pb and Zn were influenced by anthropogenic sources such as fuel combustion and waste incineration. Concentrations were remarkably higher in components from natural sources than in components from anthropogenic sources. Anthropogenic sources were significantly affected by indoor dusts than outdoor dusts. Results of pollution indices of heavy metals indicated that indoor dusts were more contaminated with heavy metal ions than outdoor dusts. The correlation analysis among trace elements indicated that components were much correlated in the order of natural sources-anthropogenic sources, anthropogenic sources-anthropogenic sources, natural sources-natural sources in both indoor and outdoor dusts. Trace element components of outdoor dusts were largely correlated than those of indoor dusts. In addition, indoor dusts were significantly affected by outdoor dusts rather than depth from the surface or the average daily number of subway passengers.

• Korean Journal of Microbiology
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• v.54 no.1
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• pp.60-68
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• 2018

A cold-active and alkaline serine protease (Pro21717) was partially purified from the Antarctic marine bacterium Pseudoalteromonas arctica PAMC 21717. On a zymogram gel containing skim milk, Pro21717 produced two distinct clear-zones of approximately 37 kDa (low intensity) and 74 kDa (high intensity). These were found to have identical N-terminal sequences, suggesting they arose from an identical precursor and that the 37 kDa protease might homodimerize to the more active 74 kDa form of the protein. Pro21717 displayed proteolytic activity at $0-40^{\circ}C$ (optimal temperature of $40^{\circ}C$) and maintained this activity at pH 5.0-10.0 (optimal pH of 9.0). Notably, relative activities of 30% and 45% were observed at $0^{\circ}C$ and $10^{\circ}C$, respectively, in comparison to the 100% activity observed at $40^{\circ}C$, and this enzyme showed a broad substrate range against synthetic peptides with a preference for proline in the cleavage reaction. Pro21717 activity was enhanced by $Cu^{2+}$ and remained stable in the presence of detergent surfactants (linear alkylbenzene sulfonate and sodium dodecyl sulfate) and other chemical components ($Na_2SO_4$ and metal ions, such as $Ba^{2+}$, $Mg^{2+}$, $Ca^{2+}$, $Zn^{2+}$, $Fe^{2+}$, $K^+$, and $Na^{2+}$), which are often included in commercial detergent formulations. These data indicate that the psychrophilic Pro21717 has properties comparable to the well-characterized mesophilic subtilisin Carlsberg, which is commercially produced by Novozymes as the trademark Alcalase. Thus it has the potential to be used as a new additive enzyme in laundry detergents that must work well in cold tap water below $15^{\circ}C$.

• Clean Technology
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• v.30 no.2
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• pp.123-133
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• 2024

Zeolite template carbon (ZTC) was synthesized as an adsorbent to remove low-concentration CH₄ from the atmosphere. The synthesis of ZTC was performed using CH₄ and C₂H₂ as carbon precursors and their impact on adsorption was investigated. ZTC was also synthesized using Y zeolite ion-exchanged with CaCl₂ and LiCl as templates to investigate the effect of using metals in ion exchange. The comparison of the carbon precursors revealed that C₂H₂ had a higher carbon yield than CH₄. The synthesized ZTC exhibited developed micropores due to carbon deposition deep inside the micropores of the zeolite template. The kinetic diameter of C₂H₂ (0.33 nm) is smaller than that of CH₄ (0.38 nm), which allowed for its deposition. The study compared metal precursors used for ion exchange and confirmed that the CaCl₂-based ZTC developed more micropores compared to the LiCl-based ZTC. The ion-exchanged Ca inhibited pore blocking by the carbon precursor, allowing it to enter the pores. The ability of synthesized ZTC to adsorb N₂ and CH₄ at 298 K was investigated. The results showed that CH₄ had a higher overall adsorption amount than N₂. The sample synthesized using C₂H₂ and CaY exhibited the highest N₂ and CH₄ adsorption capacity. However, the sample synthesized with CH₄ had the highest CH₄/N₂ gas uptake ratio, which is a crucial factor in designing an adsorption process. The observed difference was likely caused by the underdevelopment of ultrafine pores that are associated with N₂ adsorption. This resulted in a reduction of N₂ adsorption, leading to an increase in CH₄/N₂ separation.