• Toxicological Research
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• v.25 no.4
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• pp.195-201
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• 2009

Recent publications showed that metal nanoparticles which are made from $TiO_2,\;CeO_2,\;Al_2O_3,\;CuCl_2,\;AgNO_3$ and $ZnO_2$ induced oxidative stress and pro-inflammatory effects in cultured cells and the responses seemed to be common toxic pathway of metal nanoparticles to the ultimate toxicity in animals as well as cellular level. In this study, we compared the gene expression induced by two different types of metal oxide nanoparticles, titanium dioxide nanoparticles (TNP) and cerium dioxide nanoparticles (CNP) using microarray analysis. About 50 genes including interleukin 6, interleukin 1, platelet-derived growth factor $\beta$, and leukemia inhibitory factor were induced in cultured BEAS2B cells treated with TNP 40 ppm. When we compared the induction levels of genes in TNP-treated cells to those in CNP-treated cells, the induction levels were very correlated in various gene categories (r=0.645). This may suggest a possible common toxic mechanism of metal oxide nanoparticles.

• Korean Journal of Environmental Biology
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• v.34 no.2
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• pp.124-131
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• 2016

The toxic responses of flagellate Euglena agilis Carter to 8 heavy metals (Ag, Cd, Cr (VI), Cu, Hg, Ni, Pb, Zn) were measured using E. agilis system (E-Tox), an automated biomonitoring system. The E-Tox measures cell movement parameters, such as velocity, motility, and forms of the cells, as biological endpoints. $EC_{50}$ values from the E. agilis biomonitoring test were compared with the literature data from the tests with Daphnia magna, Vibrio fischeri and Euglena gracilis. Measurement of the E. agilis movement behavior and D. magna acute toxicity test were also conducted for the wastewater samples. E. agilis is less sensitive than D. magna but is comparable to or more sensitive than V. fischeri and E. gracilis for the heavy metals tested in this study. E. agilis shows prompt changes of these parameters for the toxic metal plating wastewater. Major advantages of the E-tox are automatic, easy to handle and fast ecotoxicity monitoring system compared to other biological test systems. These results imply that E. agilis biomonitoring test using E-Tox can be a putative ecotoxicity test as a good early warning tool for the monitoring of toxic wastewater.

• Journal of the Korean Chemical Society
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• v.23 no.6
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• pp.385-391
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• 1979

It was found that cupric ion selective electrode, which was prepared by mixing CuS and $Ag_2S$ with the ratio four to one and PVC, was hard and durable. The response potentials were reproducible and linear in the range from 1.0 ${\times}$ $10^{-1}M$ to 1.0 ${\times}$ $10^{-5}M$ copper (II) solution and its slope was 25.0 mV per decade concentration at $298^{\circ}K$, slightly different from Nernstian slope. The copper (II) indicating electrode was applied in precipitation titration of 1.0 ${\times}$ $10^{-2} M Cu(II)$ sample solution containing proper amounts $NaNO_3$ with 0.1 M NaOH standard solution. Also, this electrode could be used in complex titration of Zn(II), Mg(II), Ca(II) with EDTA and stability constant of EDTA complex of Ca(II) and Mg(II) was calculated by using known Cu-$EDTA^{2-}$ stability constant.

• Economic and Environmental Geology
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• v.22 no.2
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• pp.103-115
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• 1989

The Tongyoung deposits are epithermal gold and silver bearing quartz-rhodochrosite vein type deposits of late Cretaceous. They occurs in the andesite and tuff breccia member called Gyeongsang basin. Four mineralizations can be distinguished at the mine based on macrostructures. From earlist stage to lastest stage they are: stage I, base-metal quartz vein; stage II, rhodochrosite vein (IIA) and Pb-Zn vein (IIB); stage III, barren quartz vein; stage IV, calcite-ankeritic rhodochrosite veins. Gold and silver mineralizations occur predominantly in the stage I and IIB. Electrum is closely associated with galena, sphalerite and pyrite, and has chemical compositions of 50.98-64.05 atom % Ag. Sphalerite contains 2.09-5.05 mol % FeS and 0.34-2.01 mol % MnS in the stage I, and 2.01-3.41 mol % FeS and 0.21-2.80 mol % MnS in the stage IIB. The FeS and MnS contents are in general correlated, and shows a characteristic zonal arrangement of electrum. It reveals rhat FeS contents of sphalerite which precipitated before electrum, gradually decreases in a grain during its deposition ranging from about 3.3 to 2 mol %. It may be considered from the above data that an increase of $fs_2$ caused by the oxidation of ore forming fluid is more important that the decrease of temperature.

• Economic and Environmental Geology
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• v.42 no.3
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• pp.177-193
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• 2009

The Samgwang deposit consists of eight massive mesothermal quartz veins that filled NE and NW-striking fractures along fault zones in Precambrian granitic gneiss of the Gyeonggi massif. The mineralogy and paragenesis of the veins allow two separate discrete mineralization episodes(stage I=quartz and calcite stage, stage II-calcite stage) to be recognized, temporally separated by a major faulting event. The ore minerals are contained within quartz and calcite associated with fracturing and healing of veins that occurred during both mineralization episodes. The hydrothermal alteration of stage I is sericitization, chloritization, carbonitization, pyritization, silicification and argillization. Sericitic zone occurs near and at quartz vein and include mainly sericite, quartz, and minor illite, carbonates and chlorite. Chloritic zone occurs far from quartz vein and is composed of mainly chlorite, quartz and minor sericite, carbonates and epidote. Fe/(Fe+Mg) ratios of sericite and chlorite range 0.45 to 0.50(0.48$\pm$0.02) and 0.74 to 0.81(0.77$\pm$0.03), and belong to muscovite-petzite series and brunsvigite, respectiveIy. Calculated $Al_{IV}$-FE/(FE+Mg) diagrams of sericite and chlorite suggest that this can be a reliable indicator of alteration temperature in Au-Ag deposits. Calculated activities of chlorite end member are $a3(Fe_5Al_2Si_3O_{10}(OH)_6$=0.0275${\sim}$0.0413, $a2(Mg_5Al_2Si_3O_{10}(OH)_6$=1.18E-10${\sim}$7.79E-7, $a1(Mg_6Si_4O_{10}(OH)_6$=4.92E-10${\sim}$9.29E-7. It suggest that chlorite from the Samgwang deposit is iron-rich chlorite formed due to decreasing temperature from high temperature(T>450$^{\circ}C$). Calculated ${\alpha}Na^+$, ${\alpha}K^+$, ${\alpha}Ca^{2+}$, ${\alpha}Mg^{2+}$ and pH values during wallrock alteration are 0.0476($400^{\circ}C$), 0.0863($350^{\circ}C$), 0.0154($400^{\circ}C$), 0.0231($350^{\circ}C$), 2.42E-11($400^{\circ}C$), 7.07E-10($350^{\circ}C$), 1.59E-12($400^{\circ}C$), 1.77E-11($350^{\circ}C$), 5.4${\sim}$6.4($400^{\circ}C$), 5.3${\sim}$5.7($350^{\circ}C$)respectively. Gain elements(enrichment elements) during wallrock alteration are $TiO_2$, $Fe_2O_3(T)$,CaO, MnO, MgO, As, Ag, Cu, Zn, Ni, Co, W, V, Br, Cs, Rb, Sc, Bi, Nb, Sb, Se, Sn and Lu. Elements(Ag, As, Zn, Sc, Sb, Rb, S, $CO_2$) represents a potential tools for exploration in mesothermal and epithermal gold-silver deposits.

• Journal of Ginseng Research
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• v.14 no.1
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• pp.21-26
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• 1990

The chemical composition and stabilities of the purified ginseng invertase were investigated. The purified enzyme was found to be a glycoprotein composed of 80.2% protein and 19.7% total sugar. The protein component of the enzyme was composed of acidic amino acid (9.3%), basic amino acid (48.9%), nonpolar amino acid (21.4%), polar amino acid (20.4%) and 6.1% S-containing amino acid. It showed especially high contents of histidine and serine. The enzyme was inactivated almost completely by the treatment with some proteases (papain, pepsin. trypsin, pancreatin and microbial alkaline pretense) and protein denatllrants (8M urea and 6M guanidine-HC1), bolt not with glyrosidase (${\alpha}$-amylase, ${\beta}$-amylase. glcoamylese and cellullase). btonosaccharides sllch as glilrose, fructose, galactose and mannose did not exert any influence on the enzyme activity. The activity of the enzyme was inhibited by Ag+, Mn2+, Hg2+, Zn2+ and Al3+, whereas Ca2+, Mg2+, Ba2+ and Fe3+ gave rather activating effects on the enzyme activity. The enzyme was relatively stable in the VH range of VH 6 and 8, and at the temperatures below 35$^{\circ}C$.

• Microbiology and Biotechnology Letters
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• v.20 no.5
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• pp.551-558
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• 1992

The extracellular endoinulase from Streptomyces sp. 556 was purified and characterized, The culture broth was fractionated by ammonium sulfate saturation followed by DEAE-cellulose column chromatography and 5ephadex G-200 gel filtration, The ultimately purified fraction revealed a single band in 7.5% polyacrylamide gel electropherogram. The purified enzyme showed the maximal activity at pH 5.5-6.0 and $50^{\circ}C$, but lost 93% of inulase activity after 30 min incubation at $55^{\circ}C$ . The essen.tial amino acid residue for catalytic activity appeared to be tryptophan. This endo inulase was activated by $Mn^{2+}$, whereas inactivated by $Ag^{+}$, $Hg^{+}$, $Cu^{2+}$, $Zn^{2+}$, $Fe^{3+}$ and $Mo^{6+}$ EDTA and 8-hydroxyquinoline inhibited the enzyme so that the enzyme was considered to be a metalloenzyme. The Km value for inulin was 0.287 mM, and no invertase or $\alpha$-glucosidase activity was found in the enzyme.

• 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 Heritage: History & Science
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• v.49 no.2
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• pp.172-189
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• 2016

In this research, literature research on the Odong material, mixture ratio, casting method and casting facility was conducted on contemporary documents, such as Cheongong Geamul. Also, a long sword was produced using the Odong inlay technique. The sword reproduction steps were as follows; Odong alloying, silver soldering alloying, Odong plate and Silver plate production, hilt and sheath production, metal frame and decorative elements, such as a Dugup (metal frame), production, Odong inlay assembly and final assembly. For the Odong alloy production, the mixture ratio of the true Odong, which has copper and gold ratio of 20:1, was used. This is traditional ratio for high quality product according to $17^{th}$ century metallurgy instruction manual. The silver soldering alloy was produced with silver and brass(Cu 7 : Zn 3) ratio of 5:1 for inlay purpose and 5:2 ratio for simple welding purpose. The true Odong alloy laminated with silver plate was used to produce hilt and sheath. The alloy went through annealing and forging steps to make it into 0.6 mm thick plate and its backing layer, which is a silver plate, had the matching thickness. After the two plates were adhered, the laminated plate went through annealing, forging, engraving, silver inlaying, shaping, silver welding, finishing and polishing steps. During the Odong colouring process, its red surface turns black by induced corrosion and different hues can be achieved depending on its quality. To accomplish the silver inlay Odong techniques, a Hanji saturated with thirty day old urine is wrapped around a hilt and sheath material, then it is left at warm room temperature for two to three hours. The Odong's surface will turn black when silver inlay remains unchanged. Various scientific analysis were conducted to study composition of recreated Odong panel, silver soldering, silver plate and the colouring agent on Odong's surface. The recreated Odong had average out at Cu 95.57 wt% Au 4.16wt% and Cu 98.04 wt% Au 1.95wt%, when documented ratio in the old record is Cu 95wt% and Au 5wt%. The recreated Odong was prone to surface breakage during manufacturing process unlike material made with composition ratio written in the old record. On the silver plate of the silver and Odong laminate, 100wt% Ag was detected and between the two layers Cu, Ag and Au were detected. This proves that the adhesion between the two layers was successfully achieved. The silver soldering had varied composition of Ag depending on the location. This shows uneven composition of the silver welding. A large quantities of S, that was not initially present, was detected on the surface of the black Odong. This indicates that presence of S has influence on Odong colour. Additional study on the chromaticity, additional chemical compounds and its restoration are needed for the further understanding of the origin of Odong colour. The result of Odong alloy testing and recreation, Odong silver inlay long sword production, scientific analysis of the Odong black colouring agent will form an important foundation of knowledge for conservation of Odong artifact.

• Nuclear Engineering and Technology
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• v.55 no.7
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• pp.2419-2431
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• 2023

Experiments related to Boron Neutron Capture Therapy (BNCT) accomplished at the Institute of Nuclear Techniques (INT), Budapest University of Technology and Economics (TUB) are presented. Relevant investigations are required before designing BNCT for vivo applications. Samples of relevant boron compounds (H₃BO₃, BDTPA) usually employed in BNCT were investigated with neutron beam. Channel #5 in the research reactor (100 kW) of INT-TUB provides the neutron beam. Boron samples are mounted on a carrier for neutron irradiation. The particle attenuation of several carrier materials was investigated, and the one with the lowest attenuation was selected. The effects of boron compound type, mass, and compound phase state were also investigated. To detect the emitted charged particles, a traditional ZnS(Ag) detector was employed. The neutron beam's interaction with the detector-detecting layer is investigated. Graphite (as a moderator) was employed to change the neutron beam's characteristics. The fast neutron beam was also thermalized by placing a portable fast neutron source in a paraffin container and irradiating the H₃BO₃. The obtained results suggest that the direct measurement approach appears to be insufficiently sensitive for determining the radiation dose committed by the Alpha particles from the ¹⁰B (n,α) reaction. As a result, a new approach must be used.