• Korean Journal of Food Science and Technology
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• v.29 no.1
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• pp.1-8
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• 1997

A complement system-activating (anti-complementary) polysaccharide was purified from the hot water extract of young stems of Cinnamomum cassia Blume. Crude polysaccharide fraction (CC-1) was prepared from the hot water extract of the young stems followed by methanol-reflux, precipitation with ethanol, dialysis, and lyophilization. The anti-complementary activity of CC-1 was decreased greatly by periodate oxidation, but was not changed by pronase digestion. These suggest that carbohydrate moiety may be related to the activation of complement system. According to its ionic strength CC-1 was fractionated first using cetavlon to give 4 fractions, CC-2, 3, 4 and 5. Among them CC-2 fraction was found to retain the highest activity and yield. CC-2 was separated to an unabsorbed neutral sugar portion (CC-2-I) and seven absorbed acidic sugar fractions $(CC-2-II{\rightarrow}CC-2-VIII)$ on DEAE-Toyopearl 650C (Cl-). CC-2-III showing higher anti-complementary activity and yield than those of other fractions, was further purified on the gel permeation of Sephadex G-100 and Sepharose CL-6B to CC-2-IIIa-3. CC-2-IIIa-3 was determined to have a homogeneity hy GPC (Sepharose CL-6B) and HPLC. Gel chromatography using standard dextrans gave a value of $2.4{\times}10^5$ for the molecular weight. The purified polysaccharide, CC-2-IIIa-3 consisted of arabinose, xylose, glucose, galactose, galacturonic acid and glucuronic acid in a molar ratio of 5.56 : 3.77 : 1.87 : 1.00 : 5.12 : 3.13 and contained no nitrogen.

• Economic and Environmental Geology
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• v.51 no.2
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• pp.99-111
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• 2018

In this study three target radionuclides ($^{60}Co$, $^{137}Cs$, and $^{125}Sb$) were reacted with solid samples collected from the nuclear facility sites to investigate their sorption and mobility behaviors for preparing unexpected nuclear accidents. The highest sorption distribution coefficients ($K_{ds}$) of target radionuclides ($^{60}Co=947mL/g$, $^{137}Cs=2105mL/g$, $^{125}Sb=81.3mL/g$) were found in topsoil layer under groundwater condition, and the $K_d$ values of three radionuclides decreased in the order of fractured rock and bedrock samples under the same groundwater condition. High $K_d$ values of $^{60}Co$ in topsoil layer and fracture rock resulted from the clay minerals present, and the $K_d$ values decreased 58-69 % under seawater condition due to high ionic strength. $^{137}Cs$ sorption was controlled by the ion exchange reaction with $K^+$ on flayed edge sites (FES) of mica. The $^{137}Cs$ sorption was the most affected by seawater (89-97 % decrease), while $^{125}Sb$ sorption was not much affected by seawater. As the results of column and batch experiments, the retardation factors (R) of $^{137}Cs$, $^{60}Co$, and $^{125}Sb$ were determined about 5400-7400, 2000-2500, and 250-415, respectively, indicating no significant transport for these radionuclides even in fractured zone with groundwater. These results suggest that even in the case of severe nuclear accident at the nuclear facilities the mobility of released radionuclides ($^{60}Co$, $^{137}Cs$, and $^{125}Sb$) can be significantly retarded by the topsoil layer and fractured rock. In addition, the results of this study will be used for the safety and environmental performance assessment of nuclear facilities.

• Journal of Microbiology and Biotechnology
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• v.30 no.7
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• pp.996-1004
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• 2020

Various genetically engineered microorganisms have been developed for the removal of heavy metal contaminants. Metal biosorption by whole-cell biosorbents can be enhanced by overproduction of metal-binding proteins/peptides in the cytoplasm or on the cell surface. However, few studies have compared the biosorption capacity of whole cells expressing intracellular or surface-displayed metal-adsorbing proteins. In this study, several constructs were prepared for expressing intracellular and surface-displayed Ochrobactrum tritici 5bvl1 ChrB in Escherichia coli BL21(DE3) cells. E. coli cells expressing surface-displayed ChrB removed more Cr(VI) from aqueous solutions than cells with cytoplasmic ChrB under the same conditions. However, intracellular ChrB was less susceptible to variation in extracellular conditions (pH and ionic strength), and more effectively removed Cr(VI) from industrial wastewater than the surface-displayed ChrB at low pH (<3). An adsorption-desorption experiment demonstrated that compared with intracellular accumulation, cell-surface adsorption is reversible, which allows easy desorption of the adsorbed metal ions and regeneration of the bioadsorbent. In addition, an intrinsic ChrB protein fluorescence assay suggested that pH and salinity may influence the Cr(VI) adsorption capacity of ChrB-expressing E. coli cells by modulating the ChrB protein conformation. Although the characteristics of ChrB may not be universal for all metal-binding proteins, our study provides new insights into different engineering strategies for whole-cell biosorbents for removing heavy metals from industrial effluents.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.7
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• pp.712-720
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• 2008

Sediment and interstitial water samples from ten lagoons in the Northeastern coastal part of South Korea were analyzed to obtain the concentrations of metals and inorganic ligand. These data, coupled with pH and ionic strength, were used to compute the aqueous speciation of the metals in the interstitial water using the MINTEQA2 equilibrium program. The K and Na were almost entirely present as the free aqua ions, but Co, Cd, Ni, Pb and Zn were existed as various metal-ligand complexes. Metals such as Al, As, and Cr formed 3$\sim$4 metal-ligand complexes. In the interstitial water with high chloride concentrations, almost all of the metals were dominated by free aqua ions. Metals of Cd, Co, Ni, Pb and Zn were bound as chloride-metal complexes of the type M$^{x+}$ + xCl$^-$, and Fe, Mn and Mg were dominated by sulfate equilibria(M$^{2+}$ + SO$_4{^{2-}}$). Hg(II) was speciated as HgCl$_2$(aq), HgCl$_3{^-}$ and HgCl$_4{^-}$. However, in the interstitial water with low chloride concentrations, Hg(II) and Cd(II) were existed as chloride-metal complexes, metals of Cu, Mg, Mn, Ni, Pb and Zn were dominated by sulfate equilibria, and the speciation of Fe(II) was bound as Fe(OH)$_2{^+}$, Fe(OH)$_3$(aq). However, Al, As and Cr were dominated by hydroxy-metal and oxide-metal species in nearly all of the lagoons.

• Journal of the Mineralogical Society of Korea
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• v.17 no.3
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• pp.209-220
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• 2004

Adsorption behavior of Cu onto Hwangto, from Pankok-ri, Kosung-gun, suspension was studied using Cu batch adsorftion experiment and computer program MINTEQA2 and FITEQL 3.2. The sorption of copper was investigated as a function of pH, copper concentration and $NaNO_3$ background concentration (0.01 and 0.1 M). The concentration of copper was analyzed using ICP-AES. The sorption of copper onto Hwangto suspension increased with increasing pH and copper concentration. The adsorption percentage of copper drastically increased from pH 5.5 to 6.5, and reached nearly 100% at pH 7.5. Because the amount of copper solution and the ionic strength of background electrolyte may not affect the sorption of copper onto Hwangto, the copper ion may be combined at the surface of Hwangto as an inner-sphere complex. Using the MINTEQA2 program, the speciation of copper was calculated as a function of pH and copper concentration. The concentration of $Cu^{2+}$ decreased and that of $Cu(OH)_2$ increased with increasing pH. The uptake of copper in the Hwangto suspension was simulated by FITEQL3.2 program using two sites-three pKas model, which is composed of silicate reaction site and Fe oxide reaction site. The copper absorption reaction constants were calculated in the case of 2～6 mL of copper solution. The Fe oxide reaction site rapidly adsorbs copper ion between pH 4.5～6.5. Silicate reaction site adsorbs little copper ion at low copper concentration but much at high copper concentration. The removal amount of copper by precipitation was negligible in comparison with that of adsorption. The Fe oxide reaction site may has higher adsorption affinity of copper ion than silicate reaction site.

• Journal of fish pathology
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• v.7 no.2
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• pp.161-171
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• 1994

In order to elucidate the outbreak mechanisms of a new disease which is characterized by an intense congestion in central venus sinuses(CVS) of gill filaments in cultured eel. these experiments were carried out; epidemically surveyed on the cultured eel farms in the vicinity of Kunsan city and experimentaliy outbreaked the disease in the stressful condition such as thermal and handling shock and innoculated the supernatant from the homogenate of naturally severe congested gill into eels and onto the monolayer of the CHSE-214. Although the frequency of congestion in eels of B, C, D and E farms were higher than in eels of A farms, the water qualities(stocked and cultured water) among farms were not a great difference. In eels of B, C, D and E farms, the values of haematocrit(Ht), haemoglobin(Hb), total protein(Tp), albumin(Alb), glucose(Glu), magnesium(Mg) were lower and the values of calcium(Ca), methemoglobin(Met-Hb), glutamic pyruvic transminase(GPT), glutamic oxalacetic transminase(GOT) higher than in eels of A farms. These valules have not related to the frequency of congestion. An intensive congestion and dilataton in CVS of gill filaments in experimentally handling-stressed eels produced similar histopathological changes to those observed in the spontaneously diseased eel, but not in eels experimentally injected with filtering contents. The cytopathic effect on the CHSE-214 was not observed. In stressed eels the congestion of gill was increased in relation to either the decrease ranges of water temperature or the incerase in accllimated times. And increase in Ht, Met-Hb, Alb, Glu, GOT and GPT and decrease in Mg, Hb and Tp were found, which had a close relationship to congestion of gill. Cortisol were increased according to the decrease ranges in acclimated water temperature. From these results, decrease in water temperature during selection placed eels upon the stressed condition, made increase in ionic strength in blood stream, and CVS was dilatated owing to the increased blood inflow.

• Journal of the Mineralogical Society of Korea
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• v.22 no.3
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• pp.249-259
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• 2009

The objective of this research was to find out the physical properties, such as dispersion and coagulation, of soil minerals depending on the types and concentrations of the cations in aqueous solution. Hwangto samples were obtained from 90 to 130 cm from surface at Jangdong-ri, Donggang-Myon, Naju, Chonnam Province. The clay fraction (< $2\;{\mu}m$) was separated by sedimentation method from the bulk soils. Both Hwangto and clay fractions, and the same samples after removal of amorphous and crystalline iron oxides were used in this experiment. The effect of 4 cations ($Na^+$, $K^+$, $Mg^{2+}$, $Ca^{2+}$) and their concentrations on settling speed and basal spacing of the minerals were observed to examine the physical properties of the soil and clay minerals. Hwangto mainly consisted of quartz, and the clay fractions consisted of kaolinite, illite, and vermiculite. The bulk soils contained 16.3 mg/kg of amorphous iron oxides and 436 mg/kg of crystalline iron oxides. Clay fractions were dispersed better than bulk soils due to their smaller particle size than that of the bulk samples in the aqueous solution. The bulk and clay samples were dispersed better when iron oxides were removed because of coating of minerals by the iron oxides. Clay minerals were settled faster as the charge and the concentration of cations added increased. The d-spacing of kaolinite and illite did not change when 4 types of cations were added. The d-spacing of vermiculite showed $14.04\;{\AA}$ when divalent cations were added while that of vermiculite showed $13.9\;{\AA}$ when monovalent cations were added. It may be attributed to the hydration radii of cations. This study indicated that both coating of iron oxides on minerals and types and concentrations of cations affect dispersion of minerals in solution and d-spacing of expanding clay minerals such as vermiculite.

• Journal of the Korean Chemical Society
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• v.44 no.5
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• pp.403-409
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• 2000

The formation and dissociation rates of $Zn^{2+}$ Complexes with l,4,7,10-tetraaza-13,16-diox-acyclooctadecane-N,N',N",N'"-tetraacetic acid (1), 1,4,7,10-tetraaza-13,16- dioxacyclooctadecane-N,N',N",N'"-tetramethylacetic acid (2), and 1,4,7,10-tetraaza-13,16- dioxacyclooctadecane-N,N',N",N'"-tetrapropionic acid(3) have been measured by stopped-flow and conventional spectrophotometry. Observations were made at 25.0$\pm$0.1 $^{\circ}C$ and at an ionic strength of 0.10 M NaClO$_4$. The formation reactions of $Zn^{2+}$ ion with 1 and 2 took place by the rapid formation of an intermediate complex (ZnH$_3L^+$) in which the $Zn^{2+}$ ion is incompletely coor-dinated. This might then lead to be a final product in the rate-determining step.ln the pH range 4.76-5.76, the diprotonated (H2L2-) form is the kinetically active species despite of its low concentration. The stability con-stants (log$K_{(ZnH$_3$3$L^+$)}$) and specific water-assisted rate constants (koH) of intermediate complexes have been deter-mined from the kinetic data. The dissociation reactions of $Zn^{2+}$ complexes of 1,2, and 3 were investigated with $Cu^{2+}$ ions as a scavenger in acetate buffer. All complexes exhibit acid-independent and acid-catalyzed con-tributions. The effect of buffer and $Cu^{2+}$ concentration on the dissociation rate has also been investigated. The ligand effect on t dissociation rate of $Zn^{2+}$ complexes is discussed in terms of the side-pendant armsand the chelate ring sizes of the ligands.

• Ecology and Resilient Infrastructure
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• v.7 no.4
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• pp.262-273
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• 2020

Amending biopolymers such as β-glucan (BG) and Xanthan gum (XG) generally enhances soil strength by ionic and hydrogen bonds between soil particles. Thus, biopolymers have been studied as eco-friendly construction materials in levees. However, physiological responses of plants grown on soil amended with biopolymers are not fully understood. This study focuses on the effects of biopolymers on the growth of Camelina sativa L. (Camelina) under excess zinc (Zn) stress. The optimal concentrations of BG and XG were confirmed to have a 0.5% ratio in soil depending on the physiological parameters of Camelina under excess Zn stress. The Zn binding capacity of biopolymers was investigated using 1,5-diphenylthiocarbazone (DTZ). The reduction of Zn damage in Camelina was evaluated by analyzing the Zn content and expression of heavy metal ATPase (HMA) genes under excess Zn stress. Amendments of BG and XG improved Camelina growth under excess Zn stress. In DTZ staining and ICP-OES analysis, Camelina grown on BG and XG soil showed less Zn uptake than normal soil under excess Zn stress. The Zn-inducible CsHMA3 gene was not stimulated by either BG or XG amendment under excess Zn stress. Moreover, both BG and XG amendments in soil exhibit Zn-stress mitigation similar to that of Zn-tolerant CsHMA3 overexpres sed Camelina. These results indicate that biopolymer-amended soils may influence the prevention of Zn absorption in Camelina under excess Zn stress. Thus, BG and XG are proven to be suitable materials for levee construction and can protect plants from soil contamination by Zn.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.2
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• pp.101-109
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• 2022

The mobility and transport of radioactive cesium are crucial factors to consider for the safety assessment of high-level radioactive waste disposal sites in granite. The retardation of radionuclides in the fractured crystalline rock is mainly controlled by the hydrochemical condition of groundwater and surface reactions with minerals present in the fractures. This paper reports the experimental results of cesium sorption to the Wonju Granite, a typical Mesozoic granite in Korea, performed in an anaerobic chamber that mimics the anoxic environment of a deep disposal site. We measured the rates and amounts of cesium (¹³³Cs) removed by crushed granite samples in different electrolyte (NaCl, KCl, and CaCl₂) solutions and a synthetic groundwater solution, with variations in the initial cesium concentration (10^-5, 5×10^-6, 10^-6, 5×10^-7 M). The cesium sorption kinetic and isotherm data were successfully simulated by the pseudo-second-order kinetic model (r²= 0.99) and the Freundlich isotherm model (r²= 0.99), respectively. The sorption distribution coefficient of granite increased almost linearly with increasing biotite content in granite samples, indicating that biotite is an effective cesium scavenger. The cesium removal was minimal in KCl solution compared to that in NaCl or CaCl₂ solution, regardless of the ionic strength and initial cesium concentration that we examined, showing that K⁺ is the most competitive ion against cesium in sorption to granite. Because it is the main source mineral of K⁺ in fracture fluids, biotite may also hinder the sorption of cesium, which warrants further research.