• 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.

• Korean Journal of Medicinal Crop Science
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• v.11 no.1
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• pp.62-70
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• 2003

The biological activities on human immune and cancer cell lines of the four kinds of Korean mistletoes (Korean Viscum album, var. coloratum, : Korean Viscum sp. in Quercus acutissima Carr., Korean Viscum sp. in Castanea crenata, Korean Viscum sp. in Betula platyphylla, and Korean Viscum sp. in Salix koreensis) extracts were investigated. The extracts were preparated with ethanol, and fractionated with n-butanol, ethyl acetate, chloroform, hexane, and second distilled water. Cytotoxic potencies of the fractions on human normal lung cell line (HEL 299) showed under 28% in the concentration of 0.5 mg/ml. Growth inhibition effect of the Korean mistletoe extracts on the several human cancer cell lines depends on the concentration of the extracts, and extracting solvent. The hexane, chloroform, and ethyl acetate fractions indicated a strong anticancer activity, but not in aqueous and butanol fractions. Some mistletoe fractions have a different characteristic on the cancer cell lines. Stimulation on the growth of human immuno cell lines(B cell : Raji, T cell: Jurkat) of the extracts were confirmed in the ethyl acetate, chloroform, hexane fractions, but not in aqueous system.

• Economic and Environmental Geology
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• v.42 no.5
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• pp.413-426
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• 2009

The study was conducted to investigate the effects of indigenous bacteria on geochemical behavior of toxic heavy metals in contaminated paddy soil near an abandoned mine. The effects of sulfate amendment to stimulate microbial sulfate reduction on heavy metal behaviors were also investigated. Batch-type experiments were performed with lactate or glucose as a carbon source to activate indigenous bacteria in the soil under anaerobic condition for 100 days. Sulfate (250 mg/L) was artificially injected at 60 days after the onset of the experiments. In the case of glucose supply, solution pH increased from 4.8 to 7.6 while pH was maintained at 7~8 in the lactate solution. The initial low pH in the case of glucose supply likely resulted in the enhanced extraction of Fe and most heavy metals at the initial experimental period. Lactate supply exerted no significant difference on the amounts of dissolved Zn, Pb, Ni and Cu between microbial and abiotic control slurries; however, lower Zn, Pb and Ni and higher Cu concentrations were observed in the microbial slurries than in the controls when glucose supplied. Sulfate amendment led to dramatic decrease in dissolved Cr and maintenance of dissolved As, both of which had gradually increased over time till the sulfate injection. Black precipitates formed in solution after sulfate amendment, and violarite($Fe^{+2}{Ni^{+3}}_2S_4$) was found with XRD analysis in the microbial precipitates. Conceivably the mineral might be formed after Fe(III) reduction and microbial sulfate reduction with coprecipitation of heavy metal. The results suggested that heavy metals which can be readily extracted from contaminated paddy soils may be stabilized in soil formation by microbial sulfate reduction.

• The Korean Journal of Nuclear Medicine Technology
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• v.22 no.2
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• pp.74-78
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• 2018

Purpose $[^{11}C]$acetate has been proved useful in detecting the myocardial oxygen metabolism and various malignancies including prostate cancer, hepatocellular carcinoma, renal cell carcinoma and brain tumors. The purpose of study was to improve the radiosynthesis yield of $[^{11}C]$acetate on a automated radiosynthesis module. Materials and Methods $[^{11}C]$acetate was prepared by carboxylation of grignard reagent, methylmagnesium chloride, with $[^{11}C]$$CO_2$ gas, followed by hydrolysis with 1 mM acetic acid and purification using solid phase extraction cartridges. The effect of the reaction temperature ($0^{\circ}C$, $10^{\circ}C$, $-55^{\circ}C$) and cyclotron beam time (10 min, 15 min, 20 min, 25 min) on the radiosynthesis yield were investigated in the $[^{11}C]$acetate labeling reaction. Results The maximum radiosynthesis yield was obtained at $-10^{\circ}C$ of reaction temperature. The radioactivities of $[^{11}C]$acetate acquired at $-10^{\circ}C$ reaction temperature was 2.4 times higher than those of $[^{11}C]$acetate acquired at $-55^{\circ}C$. Radiosynthesis yield of $[^{11}C]$acetate increased with increasing cyclotron beam time. Conclusion This study shows that radiosynthesis yield of $[^{11}C]$acetate highly dependent on reaction temperature. The best radiosynthesis yield was obtained in reaction of grignard reagent with $[^{11}C]$$CO_2$ at $-10^{\circ}C$. This radiolabeling conditions will be ideal for routine clinical application.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.3
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• pp.241-246
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• 2007

Purpose: $[^{11}C]6-OH-BTA-1$ ([N-methyl-$^{11}C$]2-(4'-methylaminophenyl)-6-hydroxybenzothiazole, 1), a -amyloid imaging agent for the diagnosis of Alzheimer's disease in PET, can be labeled with higher yield by a simple loop method. During the synthesis of $[^{11}C]1$, we found the formation of by-products in various solvents, e.g., methylethylketone (MEK), cyclohexanone (CHO), diethylketone (DEK), and dimethylformamide (DMF). Materials and Methods: In Automated radiosynthesis module, 1 mg of 4-aminophenyl-6-hydroxybenzothiazole (4) in 100 l of each solvent was reacted with $[^{11}C]methyl$ triflate in HPLC loop at room temperature (RT). The reaction mixture was separated by semi-preparative HPLC. Aliquots eluted at 14.4, 16.3 and 17.6 min were collected and analyzed by analytical HPLC and LC/MS spectrometer. Results: The labeling efficiencies of $[^{11}C]1$ were $86.0{\pm}5.5%$, $59.7{\pm}2.4%$, $29.9{\pm}1.8%$, and $7.6{\pm}0.5%$ in MEK, CHO, DEK and DMF, respectively. The LC/MS spectra of three products eluted at 14.4, 16.3 and 17.6 mins showed m/z peaks at 257.3 (M+1), 257.3 (M+1) and 271.3 (M+1), respectively, indicating their structures as 1, 2-(4'-aminophenyl)-6-methoxybenzothiazole (2) and by-product (3), respectively. Ratios of labeling efficiencies for the three products $([^{11}C]1:[^{11}C]2:[^{11}C]3)$ were $86.0{\pm}5.5%:5.0{\pm}3.4%:1.5{\pm}1.3%$ in MEK, $59.7{\pm}2.4%:4.7{\pm}3.2%:1.3{\pm}0.5%$ in CHO, $9.9{\pm}1.8%:2.0{\pm}0.7%:0.3{\pm}0.1%$ in DEK and $7.6{\pm}0.5%:0.0%:0.0%$ in DMF, respectively. Conclusion: The labeling efficiency of $[^{11}C]1$ was the highest when MEK was used as a reaction solvent. As results of mass spectrometry, 1 and 2 were conformed. 3 was presumed.

• The Korean Journal of Mycology
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• v.12 no.3
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• pp.105-110
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• 1984

Seven seed samples of corn obtained from Kangweon Provincial Office of Rural Development, Kerea were tested for seed-borne fungi, and found that all the samples tested were infected with Fusarium moniliforme to an extent of $6.0{\sim}79.5%$. Severely infected seed samples showed poor germination on blotter. Seed component plating showed that the fungus present not only in tip caps, pericarps and endosperms, but also in embryos. Heavy infection of the fungus caused severe seed rot and seedling blight in soil, but the damage was not severe and many plants grew without any symptoms when the seeds with light infection were sown in soil. However the fungus was frequently detected from inside of the stems of healthy looking seedlings. The results indicate that the fungus transmit from seed to plant systemically. In inoculation experiments, the fungus produced stem rots on corn plants of 110 days old. The cultivar of Hwangok 3 was revealed more susceptible to the fungus than that of Suweon 19.

• Economic and Environmental Geology
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• v.22 no.1
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• pp.35-63
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• 1989

Geochemical characteristics of the Guryongsan (Ogcheon) uraniferous black slate show that this is an analogue to the conventional Chattanooga and Alum shales in occurrences. Whereas, its highest enrichment ratio in metals including uranium, among others, is explained by the cyclic sedimentation of the black muds and quartz-rich silts, and the uniform depositional condition with some what higher pH condition compared to the conditions of the known occurrences. The cyclic sedimentation, caused by the periodic open and close of the silled basin, has brought about the flush-out) of the uranium depleted water and the recharge with the new metal-rich sea water, which consequently contributed to the high concentration of metals in mud. The metal-rich marine black muds, which mostly occur in the early to middle Palaeozoic times, is attributed by the geologic conditions which related to the atmospheric oxygen contents, and these are scarcely met in the late Precambrian and/or with the onset of Palaeozoic era in the geologic evolution of the earth.

• Korean Journal of Breeding Science
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• v.42 no.6
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• pp.679-683
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• 2010

'Yeonjami' is a new sweetpotato variety developed for table use by Bioenergy Crop Research Center, National Institute of Crop Science (NICS), RDA in 2008. This variety was selected from the cross between 'Ayamurasakki' and 'Poly Cross' in 2000, and seedling and line selections were practiced from 2001 to 2003. Preliminary and advanced yield trials were carried out from 2004 to 2005. The regional yield trials were conducted at six locations from 2006 to 2008. 'Yeonjami' has cordate leaf, green vine and petiole, long elliptic storage root, purple skin and light purple flesh color of storage root. The average yield of storage root was 25.9 ton/ha in the regional yield trials, which was 15% higher than that of 'Sinjami' variety. Number of storage roots over 50 gram per plant was 2.9, and the average weight of one storage root was 153 gram. This variety was partly-resistant to Fusarium wilt and nematode. In addition, steamed 'Yeonjami' has higher polyphenol contents as 139.6 mg/100 g and higher biological activities as, which may improve the bioactivity in human.