• Korean Journal of Food Science and Technology
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• v.21 no.3
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• pp.435-440
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• 1989

The present study was attempted to investigate the mutagenicities of carbonyl compounds(methyl glyoxal, glyoxal, diacetyl, dihydroxyacetone, glycolaldehyde, glyceraldehyde and furfural) derived from Maillard reaction toward Salmonella typhimurium TA 100(base-substitution mutant) without metabolic activation . And for further Investigation of mutagenicity mechanism including desmutagenicity, active oxygen scavengers (cysteine, ${\alpha}-tocopherol$, tris (hydroxymethyl) aminomethane, catalase, ascorbic acid) and reducing agents (glutathione, sodium bisulfite) were also used. Among carbonyl compounds tested, methyl glyoxal, glyoxal, dihydroxyacetone, glycolaldehyde and glyceraldehyde exhibited mutagenicities, and methyl glyoxal showed the strongest mutagenic activity. On the other hand , the mutagenicities of carbonyl compounds were significantly suppressed by cysteine, tris (hydroxymethyl) aminomethane, glutathione and sodium bisulfite. Also, these active oxygen scavengers and reducing agents alone did not show mutagenicity in the present study.

• Applied Chemistry for Engineering
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• v.26 no.1
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• pp.99-103
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• 2015

We conducted reduction reactions of graphene oxide (GO) using three selected reductants. The conductivity and solubility of three kinds of the reduced graphene oxides (RGOs) were examined based on the degree of reduction. When the ethylene glycol (EG) was used as a reductant, the reduction reaction did not sufficiently progress and as a result the conductivity of RGOs was observed to be relatively low. For RGOs made by hydrazine (HZ) and thiourea dioxide (TU), we observed no significant differences in the degree of the reduction, conductivity and dispersity in water. However, RGO prepared by TU showed an exceptionally good solubility in N-methylpyrrolidone, and the solution was stable for more than 4 months.

• Analytical Science and Technology
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• v.18 no.5
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• pp.396-402
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• 2005

We try to look for optimum conditions of pre-reductants like L-Cysteine, KI and $FeSO_4$ when analyzing inorganic arsenic by using hydride generation-atomic absorption spectrometry, and run a comparative study of effect in the analysis of them. Also, we separated and analyzed only inorganic arsenic by using $H_2SO_4$-trap to eliminate organic arsenic which are MMA(monomethylarsonate) and DMA(dimethylarsinate). Under the conditions of mixture acid of 1.8 M HCl and 0.08 M $HNO_3$, arsenic standard solution of 20 ppb have more higher absorbance than without adding acid. In case of L-Cysteine, As(V) completely reduces into As(III) when 0.5 g of L-Cysteine is reacted more than 30 mins. in weak acid condition of approximately 0.07 M $HNO_3$ or HCl. In the event of KI, As(V) completely reduces into As(III) when 3 g of KI is reacted more than 1hour in acid condition of 0.8 M $HNO_3$. On the occasion of $FeSO_4$, the inside of tube is blocked by precipitation by mixture reaction of $NaBH_4$ and $Fe^{2+}$, therefore, comparing to other pre-reductants, reproducibility of efficiency of reducing As(V) to As(III) is low. To evaluate the accuracy of the analytical results, we use NIST SRM 1643C Trace Elements in Water ($82.1{\pm}1.2ng/mL$). The results are satisfactory.

• Journal of the Korean Chemical Society
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• v.44 no.2
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• pp.145-156
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• 2000

The content of oxidation-reduction in the chemistry textbooks from middle school to college was analyzed about the effective connection of curricular articulation. The classification was divided from five groups of 'first concept', 'same concept', 'overlap', 'development', and 'gap'. As a results, there was a deep big gap from middle school to high school and the effectiveness from high school to college was quite acceptable. Finally, the flow map, consisted of each concept between the school unit, was suggested.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2008.11a
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• pp.271-272
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• 2008

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2010.05a
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• pp.251-252
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• 2010

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2007.05a
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• pp.137-138
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• 2007

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2015.10a
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• pp.75-76
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• 2015

• Korean Journal of Environmental Biology
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• v.22 no.1
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• pp.177-183
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• 2004

Cytochrome P45O (CYP) contents and 7-ethoxyresorufin-O-deethylase (EROD) activity were determined in hepatic microsome of olive flounder (Paralichthys olivaceus) exposed to tributyltin chloride (TBTC), tributyltin oxide (TBTO), and triphenyltin chloride (TPTC). In addition, effects of in vivo (intraperitoneal injection of 7.5 mg $kg^{-1}$ BW) exposure of flounder to TPTC on CYP, NADPH cytochrome c reductase, NADH cytochrome b5 yeductase and EROD levels were measured. In in vitro exposure of hepatic microsome to organotins, TBTC, TBTO and TPTC reduced CYP contents and inhibited EROD activity. The TPTC was the strongest inhibitor, which is followed by TBTO and TBTC. The degree of inhibition, especially EROD acitivity, depended on the exposure duration. In addition, all the target enzymes in flounder were inhibited by TPTC with the in vivo exposure to TPTC. As EROD activity was the most sensitive to the inhibitions and demonstrated good reproducibility of the results, it could be used as a helpful tool toy monitor effects of organotin compounds on mixed funciton oxygenase system in marine fish.

• Journal of the Mineralogical Society of Korea
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• v.25 no.4
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• pp.263-270
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• 2012

Two kinds of uranium species, oxidized uranium(VI) and reduced uranium(IV), were prepared to be interacted with goethite and montmorillonite to identify sorption characteristic of uranium species, which are very sensitive to the redox-reaction. The reduced uranium was prepared by diluting a substantial uranium(IV) that was concomitantly produced during a sulfate reduction via a sulfate-reducing bacterium. The sorption amount of uranium(IV) by the minerals was relatively lower than that of uranium(VI) because the aqueous uranium(IV) had fine colloidal forms to cause its weak adsorption onto the mineral surfaces. We found that the uranium(IV) phase has a nano-colloid character by the transmission electron microscope, suggesting that the uranium species possibly migrating with the flow of groundwater in underground environments can be the colloidal uranium(IV) as well as the ionic uranium(VI).