• The Journal of the Petrological Society of Korea
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• v.7 no.2
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• pp.132-145
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• 1998

The coal-bearing siliciclastic rocks of the Lower Permian Jangseong Formation, Samcheog coalfield, represent a megacyclothem which shows cyclic repetitions of sandstone, shale, coaly shale, and coals. Petrographic, geochemical, and SEM studies for sandstone samples, and XRD analysis for clay minerals were carried out to understand diagenesis in the sandstones of the Jangseong Formation. The Jangseong sandstones are composed of 60% quartz (mainly monocrystalline quartz) and 36% clay matrix and cement with minor amounts of feldspar, lithic fragments and accessory minerals (less than 4%). Jangseong sandstones are classified mostly as quartzwackes and partly as lithic graywackes according to the scheme of Dott(1964). The textural relationships between authigenic minerals and cements in thin sections and SEM photomicrographs suggest the paragenetic sequence as follows; (1) mechanical compaction, (2) cementation by quartz overgrowth, (3) formation of authigenic clay minerals (illite, kaolinite), (4) dissolution of framework grains and development of secondary porosity, and (5) later-stage pore-filling by pyrophyllite. We propose that these diagenetic processes might be due to organic-inorganic interaction between the dominant framework grains and the formation water. The Al, Si ions and organic acid, derived from dewatering of interbedded organic-rich shale and coals, were transported into the Jangseong sandstones. This caused changes in the chemistry of the formation water of the sandstones, and resulted in overgrowth of quartz and precipitation of authigenic clay minerals of kaolinite and illite. The secondary pores, produced during dissolution of clay and framework grains by organic acid and $CO_2$ gas, were conduit for silica-rich solution into the Jangseong sandstones and the influx of silica-rich solution produced the late-stage pyrophyllite after the expanse of kaolinite. The origin of the solution that formed pyrophyllite is not likely to be the organic-rich formation water based on the observation of fracture-filling pyrophyllite in the Jangseong sandstones, but the process of pyrophyllite pore-filling was indirectly related to organic-inorganic interaction.

• Korean Journal of Food Science and Technology
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• v.30 no.5
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• pp.1097-1106
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• 1998

Biodegradable edible films were prepared from rice protein concentrates (RPC) made from rice wine meal by alkaline extraction and isoelectric precipitation. The effect of film forming solution pH and plasticizers were studied, and cross-linkers were added to improve mechanical properties and water vapor permeabilities (WVP) of films. Films could be formed within pH $8{\sim}11$ with tensile strength (TS) of 4.3{\sim}5.7\;MPa$. Films produced under pH 11 had the highest TS (5.7 MPa) and the lowest WVP $(0.44\;ng{\cdot}m/m^2{\cdot}s{\cdot}Pa)$. Added glycerol, polyethylene glycol 200 (PEG) and its mixture (GLY:PEG=50:50) as plasticizers also affected the mechanical properties and WVP of films. TS and elongation at break (E) of films at various plasticizer levels were $5.5{\sim}1.0\;MPa$ and $3.6{\sim}24.3%$, respectively. At the same plasticizer concentration, the highest TS was observed when glycerol was used whereas the highest E was measured when mixture was used as plasticizer. WVPs of films with thickness of $60\;{\mu}m$ were $0.39{\sim}0.54\;ng{\cdot}m/m^2{\cdot}s{\cdot}Pa$. WVP of films decreased as the ratio of glycerol/PEG 200 was decreased, and WVP increased as the total amount of plasticizer added to the films increased. Film strength was improved by the addition of small amount of sodium hydrogen sulfate, succinic anhydride, ascorbic acid and citric acid, whereas TS of films containing $0.5{\sim}2.0%$ of NaCl and $CaCl_2$ were lower than those without the salts. The highest TS (6.3 MPa) was achieved with films containing 0.1% of succinic anhydride.

• Korean Journal of Microbiology
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• v.40 no.4
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• pp.275-281
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• 2004

Our previous research has demonstrated that the bacterium, Pseudomonas sp. NFQ-l capable of utilizing quin­oline (2,3-benzopyridine) as the sole source of carbon, nitrogen, and energy was isolated and characterized [Yoon et ai. (2003) Kor. J. Biotechnol. Bioeng. 18(3):174-179]. In this study, we have found that Pseudomonas sp. NFQ-l could degrade quinoline as well as benzoate, and extended this work to characterize the catechol 1,2­dioxygenase (C1,2O) purified from the bacterium cultured in benzoate media. Initially, C1,2O has been purified by ammonium sulfate precipitation, gel permeation chromatography, and Source 15Q. After Source 15Q, puri­fication fold was increased to approximately 14.21 unit/mg. Molecular weight of C1,2O was about 33 kDa. Physicochemical characteristics (e.g., substrate specificity, Km, Vmax, pH, temperature and effect of inhibitors) of purified C1,2O were examined. C1,2O demonstrated the activity for catechol, 4-methylcatechol and 3-meth­ylcatechol as a substrate, respectively. The Km and Vmax value of C1,2O for catechol was 38.54 ${\mu}M$ and $25.10\;{\mu}mol{\cdot}min^{-1}{\cdot}mg^{-1}.$ The optimal temperature of C1,2O was $30^{\circ}C$ and the optimal pH was approximately 8.5. Metal ions such as $Ag^+,\;Hg^+,\;Ca^{2+},\;and\;Cu^{2+}$ show the inhibitory effect on the activity of C1,2O. N-terminal amino sequence of C1,2O was analyzed as ^1TVKISQSASIQKFFEEA^{17}.$ In this work, we found that the amino acid sequence of NFQ-l showed the sequence homology of 82, 71, 59 and $53\%$ compared with C1,2O from Pseudomonas aeruginosa PA0l, Pseudomonas arvilla C-1., P. putida KT2440 and Pseudomonas sp. CA10, respectively.

• Economic and Environmental Geology
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• v.56 no.5
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• pp.603-618
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• 2023

This study focused on evaluating the suitability of the WRK (waste repository Korea) bentonite as a buffer material in the SNF (spent nuclear fuel) repository. The U (uranium) adsorption/desorption characteristics and the adsorption mechanisms of the WRK bentonite were presented through various analyses, adsorption/desorption experiments, and kinetic adsorption modeling at various pH conditions. Mineralogical and structural analyses supported that the major mineral of the WRK bentonite is the Ca-montmorillonite having the great possibility for the U adsorption. From results of the U adsorption/desorption experiments (intial U concentration: 1 mg/L) for the WRK bentonite, despite the low ratio of the WRK bentonite/U (2 g/L), high U adsorption efficiency (>74%) and low U desorption rate (<14%) were acquired at pH 5, 6, 10, and 11 in solution, supporting that the WRK bentonite can be used as the buffer material preventing the U migration in the SNF repository. Relatively low U adsorption efficiency (<45%) for the WRK bentonite was acquired at pH 3 and 7 because the U exists as various species in solution depending on pH and thus its U adsorption mechanisms are different due to the U speciation. Based on experimental results and previous studies, the main U adsorption mechanisms of the WRK bentonite were understood in viewpoint of the chemical adsorption. At the acid conditions (＜pH 3), the U is apt to adsorb as forms of UO₂²⁺, mainly due to the ionic bond with Si-O or Al-O(OH) present on the WRK bentonite rather than the ion exchange with Ca²⁺ among layers of the WRK bentonite, showing the relatively low U adsorption efficiency. At the alkaline conditions (>pH 7), the U could be adsorbed in the form of anionic U-hydroxy complexes (UO₂(OH)₃^-, UO₂(OH)₄^2-, (UO₂)₃(OH)₇^-, etc.), mainly by bonding with oxygen (O^-) from Si-O or Al-O(OH) on the WRK bentonite or by co-precipitation in the form of hydroxide, showing the high U adsorption. At pH 7, the relatively low U adsorption efficiency (42%) was acquired in this study and it was due to the existence of the U-carbonates in solution, having relatively high solubility than other U species. The U adsorption efficiency of the WRK bentonite can be increased by maintaining a neutral or highly alkaline condition because of the formation of U-hydroxyl complexes rather than the uranyl ion (UO₂²⁺) in solution,and by restraining the formation of U-carbonate complexes in solution.

• Research in Plant Disease
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• v.16 no.3
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• pp.259-265
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• 2010

Pepper mild mosaic virus(PMMoV) and Cucumber mosaic virus (CMV) are important pathogens in various vegetable crops worldwide. We have found that hot water extract of Phellinus linteus mycelium strongly inhibit PMMoV and CMV infection. Based on these results, the inhibitor named as 'PLM-WE1' formulated from extract of Phellinus linteus mycelium was tested for its inhibitory effects on PMMoV and CMV infection to each local lesion host plant (Nicotiana glutinosa: PMMoV, Chenopodium amaranticolor: CMV). Pretreatment effect of PLM-WE1 against infections of each virus (PMMoV and CMV) to local host plant was measured to be 99.2% to PMMoV and 80.3% to CMV, and its permeability effect was measured to be 45.0% to PMMoV and 41.9% to CMV. Duration of inhibitory activity of PLM-WE1 against PMMoV infection on N. glutinosa was maintained for 3 days at 75% inhibition level and CMV infection on C. amaranticolor maintained for 3 days at 62% inhibition level. Inhibitory effects on systemic host plants of PLM-WE1 were measured to be 75~85% to PMMoV and 75% to CMV. Under electron microscope, PMMoV particles were not denatured or aggregated by mixing PLM-WE1. It is suggested that the mode of action of PLM-WE1 differ from that of inactivation due to the aggregation of viruses. The methanol extract of P. linteus mycelium was sequentially partitioned with haxane, ethyl acetate, BuOH and $H_2O$. The $H_2O$ fraction was showed high activity than the other fractions. The active compound was isolated with a partial acid hydrolysis, fractional precipitation with ethanol. The inhibitory effect of the precipitate isolated from 70% ethanol fraction was 99.1% to PMMoV and 88.0% to CMV. The structure of isolated compound was determined by $^1H$-NMR and $^{13}C$-NMR. This compound was identified as a polysaccharide consisting alpha or beta-glucan.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.1
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• pp.37-42
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• 1993

Influences of metal concentration, pH and temperature on metal-ligand precipitate formation were investigated, as a part of projects for removing heavy metals from aqueous solution employing the principles in metal-ligand complexation. Aqueous solutions of HA or FA were reacted with those of heavy metals with 1:1 ratio. Efficiency of humic (HA) or fulvic acid (FA) on removing metals was evaluated by separating the precipitates from soltuions with the filtering method. When HA was a counter ligand, there existed three ranges of metal concentrations affecting precipitation : precipitate fromation was not available, was reached to the maximum, and afterwards was decreased again. The concentration ratios of metal to HA for initiating complexation were dependent upon kinds of metal and concentrations of ligand. Amount of Pb to form maximum precipitates per unit mg of HA was 1.3 times higher than that of Cu. When FA was a counter ligand, concentrations of metal-FA precipitates were increased proportionally with the treated metal concentrations. Efficiency of FA fro removing Pb was nearly 100%, but it was ranged from 12 to 19% for Cu, depending on FA concentration. pH exerted a considerable effect on complexation between Pb and FA, showing precipitates were increased six times at most per unit increase of pH. Ranges of pH increasing significantly the mounts of precipitates were coincied with pH jump ranges of the titration curve of organic ligands. As increasing temperature from 15 to $55^{\circ}C$, increases of FA-Cu precipitates were doubled, but those of FA-Pb were accounted for only 6%, However, HA-metal complexation was not affected by temperature.

• Journal of Sericultural and Entomological Science
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• v.2
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• pp.1-31
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• 1962

The purpose of this treatise is to prove the presence of cystine in silk fiber through wide sampling throughout all the sericultural processes of Bombyx mori.; also to show that disulfide cross linkages exist in the silk fiber. The conclusions reached were as follows: 1. Crystalline cystine was obtained from silk fibroin using Folin's Method. 2. Analytical data showing the cystine content of silk fiber and its related materials were obtained using Sullvan's Method as follows: Material Percent Cystine A. Mulberry leaf protein 0.175 B. Silkworm egg 0.33 C. Silkworm Body, matured, fat extracted, without silk gland 0.41 D. Silk gland, matured 1.23 E. Silkworm feces none F. Silkworm pupa, fat extracted 0.30 G. Silkworm moth, fat extracted 0.60 H. Raw Silk 0.22 I. Fibroin 0.175 J. Sericin 0.30 3. The presence of cystine in the silkworm was substantiated the existence of 0.175 % methionine in mulberry leaves and 0.12% methionine in the silk gland. 4. Part of the sulfhydryl compounds in the silk gland is believed to transfer to serine and methionine, with the former being secreted into the liquid silk finally as silk fiber and the latter used for nutritive purposes in the growing of silk gland tissue. 5. The cystine content is variable by mulberry species, silkworm species, sex, breeding process, and other culturing environments. 6. Hybrid silkworms require more nutritive amino acids for effective growth than the original parents, and secrete less of them as silk fiber. 7. From such an observation, the amino acid composition of silk fiber is believed to be fairly flexible. Cystine if included in the amorphous part of the fiber, especially in sericin. 8. The result from enriching the silkworm diet with pure cystine or wool cystine did not result in any advantage, therefore it is believed that the natural cystine and methionine contents in the mulberry leafaregoodenoughforsilkwormnutrition. 9. The disulfide cross linkage in silk fiber was verified by using the Harris Method. Contraction took place following the treatment of the fiber with various salts and acids. Comparisons were made with wool fiber. 10. During these experiments, the fibrious structure of silk fiber and the net-globular liquid form were photographed microscopically. It is believed that the globules of liquid silk are net-formed by the inter attraction of the OH ion of the globular peptide and the H ion of water as shown by the hair cracking behavior of the film. The net-globular protein precipitation from the mulberry protein solution showed that mulberry is a proper diet for the formation of fibrous protein in the silk fiber. 11. The significance of the presence of cystine in silk fiber as emphasized in this paper should result in modification of the general conception that cystine is absent from this fiber. NOTICE: A part of this treatise was presented at the annual Korea Sericultural Society meeting held in 1961.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.8
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• pp.1087-1096
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• 2010

This study was conducted to investigate the physiological activity of extracts of fresh mushrooms. The components were extracted by hot water; subsequently, the hot-water extract was subjected to 60% ethanol precipitation to yield high-molecular-weight (HMW) and low-molecular-weight (LMW) fractions. Total polyphenol contents, $\beta$-glucan contents, electron-donating ability (EDA), superoxide dismutase (SOD)-like activity, nitrite-scavenging activity, fibrinolytic activity, nitric oxide (NO) production, and inhibition of NO production of the mushroom extracts were measured using lipopolysaccharide (LPS)-stimulated murine macrophages, RAW 264.7 cells. The extracts of Lentinus edodes (Berk.) Singer and Pleurotus ostreatus (Fr.) Kummer contained the highest levels of $\beta$-glucan (33.5% and 25.57%, respectively). Further, the LMW fractions of the Phellinus linteus contained the highest levels of polyphenols (233.23 mg/g). The EDA of LMW fractions (10 mg/mL) of the Phellinus linteus and Agaricus bisporus were 80.74% and 51.35%, respectively. Further, SOD-like activities of the LMW fractions were high as compared to those of the HMW fractions. Nitrite-scavenging activities of the LMW fractions (pH 1.2; concentration, 10 mg/mL) of the Phellinus linteus and Pleurotus ostreatus (Fr.) Kummer were 75.95% and 41.05%, respectively. The fibrinolytic activity of the LMW fractions of all mushrooms showed no enzyme activity by fibrin plate assay. The fibrinolytic activity of the extracts of Tricholoma matsutake was the greatest inhibitory activity at 60.4%. Further study revealed that the mushroom extracts exhibited anti-inflammatory effects on RAW 264.7 cells. The LMW fraction ($500\;{\mu}g/mL$) of the Phellinus linteus considerably inhibited NO production (100%).

• Economic and Environmental Geology
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• v.29 no.1
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• pp.65-75
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• 1996

Sulfate reduction and the precipitation of metal sulfides may have great potential to improve water quality of mine effluents in wetland treatment systems. Laboratory experiments using sulfate reducing bacteria (SRB) and limestone to treat effluents from the abandoned Dalsung tungsten-copper mine show that encouraging results, that have been attributed to sulfate reduction. Fe, Al, Cd, Cu and Zn are reduced to below detection limits with $99{\sim}100%$ metal removal rates, Mn is reduced by at least 90% to below 8.0 mg/l, and the pH is raised from 5.12 to 7.60 after 53 days of experiments. In the staged design, laboratory experiments are initiated to determine what would be reasonable substrate materials for remediation of the mine effluents. A substrate mixture containing 70% oak compost and 30% mushroom compost maintains $0.03{\sim}0.04mM$ of lactate, which provides good condition for the SRB granule. A downflow SRB wetland system is proposed as follows : 1) The lower part of the treatment system consists with a 25 cm thick layer of high quality (above 95% of $CaCO_3$) of limestone; 2) The geotextile (geonet) is recommended to be spread on the limestone bed to prevent clogging the limestones with the substrates; 3) The mixture of substrates with 70% oak and 30% spent mushroom composts, and SRB granules overlain on top of the geonet with 25 cm height. The sizes of the passive treatment systems are calculated according to metal loading and permeability criteria : 1) $220m^3$ ($15{\times}15{\times}1m$) for -1 level effluents; 2) $28m^3$ ($5.3{\times}5.3{\times}1m$) for -2 level; and 3) $2700m^3$ ($52{\times}52{\times}1m$) for the -3 level. The -3 level system needs to be broken down into 5 to 15 cells.

• Economic and Environmental Geology
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• v.35 no.5
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• pp.395-406
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• 2002

The sixty natural springs and community wells used as a drinking water in the Daejeon area are mainly located at the parks and the natural green districts. The purpose of this study is to investigate the characteristics of water quality and the contamination of the springs and the wells, and to suggest the management strategy for the springs and wells. For this study, we undertook water quality data from Daejeon City. According to the statistic analysis of water quality data, unacceptable rate as a drinking water was about 28 percent in 1999 and 24.5 percent in 2000, respectively. Major unacceptable factor is coliform, and others are bacteria, yersinia, color, turbidity, Fe and F. The unacceptable rate shows a roughly positive relationship with precipitation, that is, it shows highest rate during a rainy season between June and September. The major contamination source is likely to be the excrement of wild animals around natural springs and wells. Most of springs are vulnerable to the contamination of coliform and bacteria because of short residence time and shallow circulation in subsurface environment. The water samples collected from 31 springs or wells show weak acidic pHs, the electrical conductivity ranging from 63 to 357 $\mu\textrm{S}$/cm, and the hydrochemical types of Na(Ca)-HC0$_3$ and Ca-HC0$_3$. The groundwater samples of low total dissolved solid(TDS) belong to Na(Ca)-HC0$_3$. type, and the groundwater of high total dissolved solid is shifted towards Ca-HC0$_3$ type in the chemical composition. These hydrochemical characteristics indicate that most natural springs is in the early stage of geochemical evolution. The natural springs should be closed during a rainy season, which shows a high contamination rate. We suggest that a protection barrier around the springs should be built to keep wild animals away from the springs.