• Corrosion Science and Technology
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• v.3 no.5
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• pp.194-197
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• 2004

The corrosion resistance of several kind of ME (Metal Evaporated) tape has been investigated both in mild sulfuric acid solution and NaCl solution by electrochemical impedance spectroscopy. It was found that the degradation of ME tapes was accelerated with increasing the concentration of sulfuric acid. There was no significant change in corrosion resistance when the concentration of NaCl was under 3.5 wt%. However, the impedance value decreased when the concentration of NaCl was up to 10 wt%. The degradation of backside of ME tapes was also investigated by AC impedance measurements. The results showed that the impedance behavior of backside plastic film changed with the concentration of sulfuric acid even at the beginning of immersion, implying the changing of the permeability for the backside of ME tapes. It was also found that the corrosion resistance of DVC (Digital Video Cassette) ME tape was better that that of Hi-8mm ME tapes in sulfuric acid solutions. Also, the backside of DVC ME tape showed better water resistance than that of Hi8 ME tapes.

• Journal of Pharmaceutical Investigation
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• v.29 no.3
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• pp.171-177
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• 1999

Lidocaine(2-Diethylaminoaceto-2', 6'-xylidide) was transdennally delivered by iontophoresis and the effect of enhancer on the delivery of lidocaine was studied. We delivered lidocaine through the skin of hairless mouse using diffusion cell and investigated the effect of the amount of cation salts such as sodium chloride, calcium acetate, zinc acetate and aluminum acetate on the drug delivery. The amounts of transported drugs and adsorbed metal ions were measured by HPLC(High Perfonnance Liquid Chromatography) and AAS(Atomic Absorption Spectrophotometry), respectively. The addition of zinc acetate and aluminum acetate greatly enhanced the delivery of lidocaine. The detection of two metal ions by AAS seemed to support the idea that the astringency effect of these ions were the main reason for the enhancement of transdermal delivery.

• Textile Coloration and Finishing
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• v.24 no.4
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• pp.247-252
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• 2012

The objective of this study was to find an appropriate method and process for protecting the green color in bamboo leaves and subsequent extraction of the green colorants, chlorophyll. Various inorganic salts including cupric sulfate, ferric sulfate, and zinc chloride were employed as green color protectors. Accordingly, the effects of metal salts and treatment conditions on color protection were investigated to find appropriate protector and conditions. And also, the efficacy of bamboo colorants as a natural green dye was evaluated through dyeing and colorfastness tests. Antimicrobial activity of dyed fabrics was measured by shake flask method in terms of bacterial reduction rate using Staphylococcus aureus(ATCC 6538). On the basis of experimental results for stabilizing bamboo leaves colorants, it was confirmed that Cu was the most appropriate metal type considering dye uptake, photostability and light fastness, and its optimum concentration was 0.025%. After the stabilization, the colorants were extracted efficiently at NaOH aqueous solution of 1.00%. It was concluded that bamboo leave has a high potentiality as new resources to produce a natural green dye with antimicrobial functionality.

• Nutrition Research and Practice
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• v.3 no.1
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• pp.15-22
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• 2009

This study was performed to investigate the effect of chlorella on cadmium (Cd) toxicity in Cd-administered rats. Sixty male Sprague-Dawley rats (14 week-old) were blocked into 6 groups. Cadmium chloride was given at levels of 0 or 325 mg (Cd: 0, 160 ppm), and chlorella powder at levels of 0, 3 and 5%. Cadmium was accumulated in blood and tissues (liver, kidney and small intestine) in the Cd-exposed groups, while the accumulation of Cd was decreased in the Cd-exposed chlorella groups. Fecal and urinary Cd excretions were remarkably increased in Cd-exposed chlorella groups. Thus, cadmium retention ratio and absorption rate were decreased in the Cd exposed chlorella groups. Urinary and serum creatinine, and creatinine clearance were not changed in experimental animals. In addition, metallothionein (MT) synthesis in tissues was increased by Cd administration. The Cd-exposed chlorella groups indicated lower MT concentration compared to the Cd-exposed groups. Moreover, glomerular filtration rate (GFR) was not changed by dietary chI orella and Cd administration. According to the results above, this study could suggest that Cd toxicity can be alleviated by increasing Cd excretion through feces. Therefore, when exposed to Cd, chlorella is an appropriate source which counteracts heavy metal poisoning, to decrease the damage of tissues by decreasing cadmium absorption.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.02a
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• pp.165-169
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• 2004

It was studied on the reductive extraction between the eutectic salt and Bi metal phases. The solutes were zirconium and the rare earth elements, where zirconium was used as the surrogate for the transuranic(TRU) elements. All the experiments were performed in a glove box filled with argon gas. Two types of experimental conditions were used -high and low initial solute concentrations in salt. Li-Bi alloy was used as a reducing agent to reduce the high chemical activity of Li. The reductive extraction characteristics were examined using ICP, XRD and EPMA analysis. Zirconium was successfully separated from the rare earth elements by the reductive extraction method. The LiF-NaF-KF system was favorable among the fluoride salt systems, whereas the LiCl-KCl system was favorable among the chloride salt systems. When the solute concentrations were high, intermetallic compounds were found near the salt-metal interface.

• Analytical Science and Technology
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• v.9 no.3
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• pp.221-234
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• 1996

Basic studies for the effective extraction of dibenzylammonium dibenzyldithiocarbamate(DBADBDC) complexes of Ag(I), Pd(II), Au(III) and Pt(IV) into chloroform have been conducted. The effects of pH on the extraction of ligand itself and metal cemplexes showed that DBADBDC itself was uniformly extracted in the pH range of 2~9 and metal complexes were effectively extracted at the pH range as follows. That is, Ag(I) : in an acidic aqua medium, Pd(II) : > 4, Au(III) : wide range, and Pt(IV) : > 3. The distribution ratio and extractabilities were obtained from the partition and extraction equilibria of metal-DBDC complexes between aqueous solution and chloroform. Ag(I) : log D=4.226 : E(%)=99.9% in the aqueous solution of pH 0, Pd(II) : log D=1.804 : E(%)=98.5% at pH 4~7, Au(III) : log D=3.755 : E(%)=99.9% at pH 2~10, and Pt(IV) : log D=0.165 : E(%)=57.2% at pH 8.0. And also mole ratio of metal ion to ligand in complexes were determined by mole ratio method : 1 : 1 for Ag(I) and 1 : 2 for Pd(II), Au(III) and Pt(IV). $Cl^-$ was included as a coordination species in complexes of Au(III) and Pt(IV). Besides, extraction mechanisms of compleses sere examined in the presence of chloride ion in an aquous solution, and extraction reactions and estraction constants could be proposed and calculated, respectively.

• Journal of Preventive Medicine and Public Health
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• v.39 no.3
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• pp.199-204
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• 2006

Objectives: Mercury is a hazardous organ-specific environmental contaminant. It exists in a wide variety of physical and chemical states, each of which has unique characteristics for the target organ specificity. Exposure to mercury vapor and to organic mercury compounds specifically affects the CNS, while the kidney is the target organ for inorganic Hg compounds. Methods: In this study, mercury chloride $(HgCl_2)$ was studied in a renal derived cell system, i.e., the tubular epithelial Madin-Darby canine kidney (MDCK) cell line, which has specific sensitivity to the toxic effect of mercury. MDCK cells were cultured for 6-24 hr in vitro in various concentrations (0.1-100 M) of $HgCl_2$, and the markers of apoptosis or cell death were assayed, including DNA fragmentation, caspase-3 activity andwestern blotting of cytochrome c. The influence of the metal on cell proliferation and viability were evaluated by the conventional MTT test. Results: The cell viability was decreased in a time and concentration dependent fashion: decreases were noted at 6, 12 and 24 hr after $HgCl_2$, exposure. The increases of DNA fragmentation were also observed in the concentrations from 0.1 to 10 M of $HgCl_2$ at 6 hr after exposure. However, we could not observe DNA fragmentation in the concentrations more than 25 M because the cells rapidly proceeded to necrotic cell death. The activation of caspase-3 was also observed at 6 hr exposure in the $HgCl_2$ concentrations from 0.1 to 10 M. The release of cytochrome c from the mitochondria into the cytosol, which is an initiator of the activation of the caspase cascade, was also observed in the $HgCl_2-treated$ MDCK cells. Conclusions: These results suggest that the activation of caspase-3 was involved in $HgCl_2-induced$ apoptosis. The release of cytochrome c from the mitochondria into the cytosol was also observed in the $HgCl_2-treated$ MDCK cells. These findings indicate that in MDCK cells, $HgCl_2$ is a potent inducer of apoptosis via cytochrome c release from the mitochondria.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.4 no.3
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• pp.173-183
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• 2000

This study measured the zeta potential of both latex colloidal particles with carboxylate surface groups and glass beads (collectors) with silanol surface group employing various solution with different chemical characteristics. The results have been compared with the surface chemistry theory. The zeta potential of the particle and collector increased with increasing pH up to 5.0 regardless of the solution chemistry. For a monovalent electrolyte solution(sodium chloride solution) the zeta potential steadily increased until the pH reached 9.5. In contrast, little change in zeta potential was made between 5.0 and 9.5 for a divalent electrolyte solution (sodium chloride solution) the zeta potential steadily increased until the pH reached 9.5. In contrast, little change in zeta potential was made between 5.0 and 9.5 for a divalent electrolyte solution (calcium chloride solution). In other words, the more the pH decreases, the larger the effect of neutral salts, such as NaCl and CaCl$_2$, have on the ζ-potential values. In this study, the PZPC(point of zero proton condition) of the particle and collector occurred below a pH of 3.1, H(sup)+ and OH(sup)- acted as a PDI (potential determining ion), and Na(sup)+ acted as an IDI(indifferent ion). The magnitude of the negative ζ-potential values of the particle and collector monotonically increased as the concentrations of Na(sup)+ or Ca(sup)2+([Na(sup)+] or [Ca(sup)2+]) decreased (the values of pNa or pCa increased). In the case of latex particles, the ζ-potential should aproach zero (isoelectric point; IEP) asymptotically as the pNa approaches zero, while in the case of calcium chloride electrolyte, ζ-potential reversal may be expected to occur around 3.16$\times$10(sup)-2MCaCl$_2$(pCa=1.5). pH, valance and ionic strength can be used in various ways to improve the water treatment efficiency by modifying the charge characteristics of the particle and collector. Predictive capability is far less certain when EDL(electrical double layer) repulsive forces exist between the particle and collector.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.1
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• pp.68-80
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• 2006

This study aimed to prepare the fundamental data and assess the status and trend of exposure level for 5 chemical substances such as sulfuric acid, hydrogen chloride, ammonia, formaldehyde and phenol in manufacturing industry by type of industry, working process, and size of factory, chronological change. Subjects related to this study consist of 146 factories, 12 industries and 17 working processes located in Busan area from Jan. 1997 to Dec. 2001. 1. All 5 kinds of chemical substances by type of industry, working process were generated in chemical manufacturing industry. There were founded in 8 types of industries and 13 types of working processes for ammonia, which is the highest number of in all 5 chemical substances. 2. In terms of the exposure level for 5 chemical substances by type of industry, working process, geometric mean concentration for sulfuric acid was $0.40mg/m^3$ in manufacture of chemicals and chemical products, $0.30mg/m^3$ in compounding process, for hydrogen chloride was 0.57 ppm in manufacture of basic metal, 0.48 ppm in dyeing process, for ammonia was 1.11 ppm in manufacture of rubber and plastic products, 0.94 ppm in buffing process, for formaldehyde was 0.49 ppm in manufacture of wood and of products of wood and cork, except furniture; manufacture of articles straw and plating materials, 0.53 ppm in mixing process, and for phenol were 0.53 ppm in manufacture of chemical and chemical products, 0.55 ppm in compounding process, respectively. Results for 5 chemical substances by type of industry and working process were significantly higher than those of the others(p<0.05). 3. The exposure level for hydrogen chloride, formaldehyde were significantly increased by size of industry (p<0.01). ammonia was significantly decreased by size of industry (p<0.01). 4. In trend of the concentration difference of five chemical substances by chronology, geometric mean concentration for sulfuric acid was significantly increased (p<0.01), hydrogen chloride and ammonia were significantly decreased by year (p<0.05) and for formaldehyde and phenol were decreased in chronological change. According to the above results 5 chemical substances were founded together in a way mixed in the same places one another and concentrations of chemical substances by industry, working process, size of industry and year appeared markedly. The authors recommend more systemic and effective work environmental management should be conducted in workplaces generating five chemical substances.

• Journal of Mushroom
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• v.18 no.4
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• pp.387-392
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• 2020

Eight dried ear mushroom products (three domestic and five Chinese products) distributed in Korea were analyzed for 321 residual pesticides, 7 heavy metals, and 3 types of radioactivity. Residual pesticides in the domestic products were not detected. However, chlorpyrifos, isoprocarb, mepiquat chloride, and carbendazim were detected in four Chinese products, all of which were below the allowable residual limit. Among the detected pesticide ingredients, only the residue for mepiquat chloride has been established to be present in ear mushrooms. In the heavy metal test, trace amounts of heavy metals were detected in all samples. However, none of the samples exceeded the allowable residual limits, except for one domestic sample that exceeded the standard value of 0.3 mg/kg for lead. Radioactivity tests confirmed that levels were below the minimal detectable activity value in all samples.