• Korean Journal of Ecology and Environment
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• v.52 no.4
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• pp.324-332
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• 2019

In this study, the possibility of a follow-up study on environmental pollution in domestic freshwater was identified by analyzing fish otoliths using Laser ablation-inductively coupled mass spectrometry (LA-ICP/MS). Fish otolith are known to be affected by the environment in which fish live. As a result, research on this subject is active in many countries; however, this is not the case in Korea. Therefore, in this study, the possibility of tracing environmental pollution using fish otoliths was identified by analyzing the components of metal elements used as indicators for environmental pollution. For the component analysis of metallic elements LA-ICP/MS, which can shorten analysis time by reducing the pretreatment process, was used. Sampling was conducted by dividing the research and the background area and carp, a freshwater species, was selected as the experimental fish species subject. Based on the established LA-ICP/MS conditions, the concentration of the metallic elements in the fish otoliths collected in the research area was 2202.9 mg kg^-1, 2.03 times higher than the 1,086.3 mg kg^-1 in the background area. All elements except for Li and U, were found to be higher in the research area than in the background area. Compared with the sediment measuring net analysis data, the distribution tendency of Zn, Pb, and Cu in sediment metal element concentrations in the two regions and distribution of metal element concentration in fish otoliths were similarly shown. These results confirm that fish otoliths can be used to track environmental pollutants, such as in sediments.

• Herbal Formula Science
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• v.24 no.2
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• pp.80-99
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• 2016

Objectives : Instrumental chemical analysis was utilized to investigate the effect of Add-Omit-Saenghyeoryunbu-eum(AO-SHU) on diabetic treatment. One of the most exciting, yet also controversial, arguments is the safety and biological mechanisms of the natural medicine on human body. Therefore, the aim of this study is to provide a better understanding on bioactive chemical components, hazards of heavy metal contamination and biological mechanism of the diabetic medicine composed of 12 different natural herbs. Methods : To study bioactive compound and metallic component in the diabetic medicine in detail, LC-MS/MS (Liquid Chromatography-Mass/Mass), GC (Gas Chromatography) and ICP (Inductively Coupled Plasma) were utilized to characterize the extract of the diabetic medicine and the result was compared with 18 marker substances selected from literature survey. In addition, in vitro assay experiments including GPR 119 activity and human DGAT-1 inhibition, and OGTT (Oral Glucose Tolerance Test) were performed to verify the effectiveness of this medicine on diabetic treatment. Results : Out of 18 marker substances, 9 bioactive compounds were identified from LC-MS/MS analysis which include Citruline, Catalpol, Berberine, Ginsenoside Rb1, Ginsenoside Rg1, Oleanolic acid, β-Sitosterol, Mangiferin, and Schizandrin. ICP study on 245 residual pesticides revealed that 239 species were not detected but 6 species, Dimethomorph, Trifloxystrobin, Pyraclostrobin, Isoprocarb, Carbaryl and Flubendiamide, while the amounts are trace levels, below permitted concentrations. The biological activity was observed in vitro assay and Oral Glucose Tolerance Test(OGTT), which are consistent with a preliminary clinical test result, a drop in blood sugar level after taking this herbal medicine. Conclusions : Instrumental chemical analysis using LC-MS/MS, GC, and ICP was conducted successfully to identify bioactive compounds in AO-SHU for the treatment of diabetes, finding 9 bioactive compounds. Furthermore, in vitro assay experiments and OGTT show that AO-SHU has its biological activities, which imply that it can be a candidate for the future diabetes remedy.

• Economic and Environmental Geology
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• v.18 no.4
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• pp.343-355
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• 1985

Spectral reflectivity and microhardness were measured quantitatively on polished surfaces of a selection of bireflecting minerals obtained from several well known metallic deposits. Incremental errors are much higher than decremental errors and errors were found to be lowest in the spectral region close to the green wavelength ($544m{\mu}$). The characteristics of the spectral profile are significant in their control of white light color. The covellite and graphite have reflectivity profiles similar in shape for each principal direction, showing noticeable difference in magnitude between the profiles: The spectral reflectivity of covellite parallel to the extraordinary vibration is higher (R$$\simeq_-$$10%) than that parallel to the ordinary vibration and graphite shows opposite feature. Reflectivity of the enargite and famatinite cut parallel to the cleavage plane is always higher (R$$\simeq_-$$5%) than that of the section cut normal. The optical symmetry of 5 bireflecting minerals was determined by noting the variation in reflectivity at $544m{\mu}$. The data indicate that covellite is optically uniaxial positive and graphite is optically uniaxial negative. The Rm values for enargite and famatinite are clearly closer to the minimum value for the mineral ($R_1$) than to the maximum value ($R_2$) : the minerals can be recognized as optically biaxial positive. Enargite and famatinite cut parallel to cleavage have much higher hardness values (HV=> $200kg/mm^2$) than those cut normal to cleavage. Vickers indentations exhibit characteristic features for all the bireflecting mineral species studied. Broad radicle groupings of the mineral species can be made with regard to the reflectivity microhardness numbers.

• Journal of Life Science
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• v.26 no.11
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• pp.1308-1312
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• 2016

Heavy metals such as gallium (Ga) cause serious physiological damage to exposed organisms, mostly of aquatic species. Ga one of the inter-metallic, transition elements increasingly being used in making high-speed semiconductors, such as Ga arsenide. The purposes of this study were to investigate the effects of Ga on acute toxicity, serum biochemical changes, and erythrocyte morphological changes in the blood stream of goldfish (Carassius auratus). Median lethal concentrations were determined in acute tests. The 96 hr $LC_{50}$ value was 9.15 mg/ml. Goldfish were exposed to different Ga concentrations (2.0, 4.0, and 8.0 mg/ml) for 30 days to assess its toxic effects. The results indicate that the measured serum biochemistry parameters (including glucose, blood urea nitrogen, creatinine, cholesterol, and triglyceride) of the Ga-exposed fish groups differed significantly from the untreated fish group. In addition, a change in the erythrocytes' morphology at a high concentration (8.0 mg/ml) of Ga exposure shows respiratory problems. Our results suggest that 2.0 mg/ml is proposed as a biologically safe concentration that can be used for establishing tentative water quality criteria concerning the same-size goldfish.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.4
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• pp.280-291
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• 2007

Much research has been conducted in the field of phytoremediation since the discovery of the range of plants known as hyperaccumulators. Research has focused simultaneously on elucidating the mechanism of metal(loid) accumulation and development of practical techniques to enhance accumulation efficiency. To date, it is generally understood that there are five specific mechanisms employed by hyperaccumulating plant species that are either not or under utilized by non-hyperaccumulators. These include 1) enhanced metal(loid)s uptake through the root cell, 2) enhanced translocation in plant tissue, 3) detoxification and sequestration, 4) enhanced metal availability in soil:root interface, and 5) active root foraging toward metal(loid) enriched soils. Among these mechanisms, understanding of the plant-root effect on metal(loid) dynamics and subsequent plant uptake is vital to overcome the inherit limitation of phytoremediation caused by low metal(loid) solubility in soils. Plant roots can influence the soil chemistry in the rhizosphere through changes in pH and exudation of organic compounds such as low-molecular-weight organic acids (LMWOAs) which consequently change metal(loid) solubility. The decrease in soil pH by plant release of $H^+$ results in increased metal solubility. Elevated levels of organic compounds in response to high metal soil concentrations by plant exudation may also increases metal concentration in soil solution through formation of organometallic complexes.

• Journal of the Korean Chemical Society
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• v.34 no.6
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• pp.561-568
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• 1990

Voltammetric behavior of some light lanthanide ions (La$^{3+}$, Pr$^{3+}$, Nd$^{3+}$, Sm$^{3+}$, and Eu$^{3+}$) in various supporting electrolytes has been investigated by several electrochemical techniques. The peak potentials and the peak currents, their dependency on the concentration, temperature and pH effects, the reversibility of the electrode reactions are described. The reduction of La$^{3+}$, Pr$^{3+}$ and Nd$^{3+}$ in 0.1 M lithium chloride proceeds by a three-electron change directly to the metallic state (Ln$^{3+}$ ＋ 3e- → Ln$^0$) and charge transfer is totally irreversible. However, the reduction of Sm$^{3+}$ in 0.1 M tetramethylammonium iodide and Eu$^{3+}$ in 0.1 M lithium chloride proceeds in two stages (Ln$^{3+}$ ＋ e- → Ln$^{2+}$ and Ln$^{2+}$ ＋ 2e- → Ln$^0$). At pH values lower than ca.4 the hydrated lanthanide species (Ln(OH)$^{2+}$) reduced before the lanthanide ions (Ln$^{3+}$) due to the catalytic effect of hydrogen ions, and peak current increase with in the order Eu$^{3+}$ < Sm$^{3+}$ < Nd$^{3+}$ < Pr$^{3+}$ < La$^{3+}$ in differential pulse polarography. Some representative plots of $i_{pc}V^{-1/2} (proportional to current function) vs. V show considerable influence of hydrogen ion/lanthanide ion concentration in cyclic voltammetry. It is shown that a reaction of lanthanide ions with proton and/or water and catalytic reaction is enhanced at lower pH and at decreased lanthanide ion concentration.

• Korean Journal of Materials Research
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• v.9 no.3
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• pp.244-250
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• 1999

MOCVD TiN films were prepared from a new TiN precursor, tetrakis(etylmethylamino)titanium (TEMAT) and ammonia. Deposition of TiN films from a single precursor, TEMA T yielded the growth rates of $70 to 1050\AA$/min, depending on the deposition temperature. Furthermore, the excellent bottom coverage of -90% over $0.35\mu\textrm{m}$ contacts was obtained at $275^{\circ}C$. The addition of ammonia to TEMA T lowered the resistivity of as- deposited TiN film to ~ $800\mu\omega-cm$ from $3500~6000\mu\omega-cm$ and improved the stability of TiN film in air. Examination of the films by Auger electron spectroscopy(AES) showed that the oxygen and carbon contents decreased with the addition of ammonia. However, increasing ammonia flow rate decreased the bottom coverage of TiN films over $0.5\mu\textrm{m}$ contacts, probably due to the high sticking coefficient of intermediate species produced from the gas phase reaction of TEMA T and ammonia. Based on the byproduct gases detected by the quadrupole mass spectrometer (QMS), the transammination reaction was proposed to be responsible for TiN deposition. In addition, XPS analysis revealed that the carbon in the films made from TEMA T and ammonia was metallic carbon, suggesting that $\beta$-hydrogen activation process occurs competitively with the transammination reaction.

• The Korean Journal of Malacology
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• v.25 no.3
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• pp.223-230
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• 2009

Metallothioneins (MTs) play a key role in metallic homeostasis and detoxification in most living organisms. In an attempt to study the biological functions and significance of MT in a snail, we cloned and partially characterized the MT gene from the left-handed snail, Physa acutawhich has been regarded as a potential biomonitering species for fresh water. The complete cDNA sequence of PaMT cDNA was identified from the expressed sequence tag (EST) sequencing project of Physa acuta. The coding region of 180 bp gives 60 amino acid residues including the initiation methionine and termination codon. Clustering and phylogenic analysis of PaMT with other MT amino acid sequences show that it has some identities to Helix pomatia (60%), Arianta arbustorum (58%), Perna viridis (49%), Mytilus edulis (49%), Bathymodiolus azoricus (49%), Bathymodiolus azoricus (48%) and Bathymodiolus sp. FD-2002 (48%). Time dependent induction for PaMT from P. acuta exposed with cadmium (50 ppb) indicated that PaMT was induced at 4-8 hr after exposure. It remains to further develop PaMTas a potential biomarker for water contamination in fresh water.

• Resources Recycling
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• v.30 no.4
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• pp.11-19
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• 2021

Arsenic (As) oxidation followed by precipitation from a high-As(III)-containing leaching solution derived from a sulfidic ore was investigated in this study to remove aqueous As from the solution using activated carbon (AC) with air injection as an oxidant. To obtain the initial leaching solution, a domestic sulfidic ore was leached in a sulfuric acid solution at pH 1 and 50℃ for 95 h, and approximately 7 g/L of Fe and 3 g/L of As were leached out. To determine the effect of the oxidative reaction utilizing AC with air injection, the leaching solution was tested under the following five oxidative conditions at an initial pH of 1 and 90℃ for 72 h: air-only injection; air injection with 1, 5, and 10 w/v% of AC addition; and H₂O₂ addition. The tests in the presence of both air and AC revealed that the oxidation kinetics and As removal were improved by the reaction between the metallic species and the surface group formed on the AC surface. In addition, the greater the amount of AC added, the better was the reaction efficiency, removing 93-94% of As with more than 5 w/v% of AC addition. Finally, X-ray diffraction analysis confirmed that the precipitate formed from the oxidative reaction was scorodite (FeAsO₄·2H₂O).

• Economic and Environmental Geology
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• v.12 no.1
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• pp.41-49
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• 1979

A literature review is made on the physical and chemical characteristics of clay minerals in acidic solutions from the mineralogical and hydrometallurgical viewpoints. Some of the important characteristics of clays are their ability to cation exchange, swelling, and incongruent dissolution in acidic solutions. Various clay minerals can take up metallic ions from solution via cation exchange mechanism. Generally, cation exchange capacity increases in the following order : kaolinite, halloysite, illite, vermiculite, and montmorillonite. In acidic solutions, the cation uptake such as copper by clay minerals is strongly inhibited by hydrogen and aluminum ions and thus is not economically significant factor for recovery of metals such as uranium and copper. In acidic solutions, the cation uptake is substial. Swelling is minimal at lower pH, possibly due to lattice collapse. Swelling may be controllable with montmorillonite type clays by exchanging interlayer sodium with lithium and/or hydroxylated aluminum species. The effect of add on clay minerals are : 1. Division of aggregates into smaller plates with increase in surface area and porosity. 2. Clay-acid reactions occur in the following order: (i) $H^+$ replacement of interlayer cations, (ii) removal of octahedral cations, such as Al, Fe, and Mg, and (iii) removal of tetrahedral Al ions. Acid attack initiates, around the edges of the clay particles and continued inward, leaving hydrated silica gel residue around the edges. 3. Reaction rates of (ii) and (iii) are pseudo-1st order and proportional to acid concentration. Rate doubles for every temperature increment of $10^{\circ}C$. Implications in in-situ leaching of copper or uranium with acid are : 1. Over the life span of the operation for a year or more, clays attacked by acid will leave silica gel. If such gel covers the surface of valuable mineral surfaces being leached, recovery could be substantially delayed. 2. For a copper deposit containing 0.5% each of clay minerals and recoverable copper, the added cost due to clay-acid reaction is about 1.5c/lb of copper (or 0.93 lbs of $H_2SO_4/1b$ of copper). This acid consumption by clay may be a factor for economic evaluation of in-situ leaching of an oxide copper deposit.