• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.4
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• pp.289-295
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• 1993

The present paper was investigated in the inhibitory action of vegetable and seaweed water-soluble extracts on the formation of carcinogenic N-nitrosodimethylamine(NDMA). The vegetable and seaweed extracts obtained from garlic(Allium sativum), onion(Allium cepa), green onion(Allium fistuiosum), chinese pepper(Fagara mandshurica), green pepper(Capsicum annuum), red pepper(Capsicum annuum), ginger(Zingiber officinale), carrot(Daucus carota), laver(Porphyra tenera), sea lettuce(Entero compresa), sea mustard(Undaria pinnatifida) and sea staghorn(Codium fragile) were incubated with sodium nitrite-dimethylamine mixtures at $37^{\circ}C$ under different pH conditions The formation of NDMA was reduced to $10{\sim}40\%\;and\;25{\sim}50\%$ by the addition of vegetable and seaweed extracts 30mg at pH 1.2, respectively. The inhibition degree by the extracts at pH 1.2 was similiar to that at pH 4.2 and to that by ascorbic acid at pH 1.2. The inhibitory action of the extracts against NDMA formation was not decreased by heat treatment at $80^{\circ}C$ for 10min, but decreased by the treatment of sodium borohydride. It is assumed that reducing powers of the extracts participated in their inhibitory actions.

• Microbiology and Biotechnology Letters
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• v.35 no.2
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• pp.163-172
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• 2007

This study was designed to investigate that inorganic germanium $(GeO_2)$ did not exist in germanium-fortified yeast or obtained to non-detectable value by current analytical methods and equipments. For this purpose, we achieved $GeO_2$ qualitative analysis protocol which could be the scientific basis of the study. Since reddish brown precipitate was formed from the reaction of $GeO_2$ with 1 equiv $NaBH_4$, and dark brown precipitate was also formed from the reaction of $GeO_2$ with 2 equiv $NaBH_4$, $GeO_2$ was qualitatively analyzed by observing these particular colored-precipitates. Because no color change was showed from the reaction between $NaBH_4$ and $SiO_2$, the color change could be caused by charge transfer transition on Ge-O and B binding properties. The reaction between $NaBH_4$ and germanium-fortified yeast did not show any color change and precipitate formation which meant no $GeO_2$ existed in germanium-fortified yeast. The reaction between $NaBH_4$ and supernatant specimen collected from the outside of dialysis membrane (MWCO 1,200 dalton) did not show any color change and precipitate formation. Therefore, we considered that the both germaniums in and outside of the dialysis membrane were organic germaniums. Germanium-fortified yeast which was biosynthesized organic germanium can be applied not only as a new functional material for improving health, prevention and treatment of chronic degenerative diseases including cancers, and the regulation of immune system, but also as a new materials.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.1008-1012
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• 2008

Nanoscale zero-valent iron(nZVI) is famous for its high reactivity originated from its high surface area and it has received considerable attentions as one of the latest innovative technologies for treating contaminated groundwater. Due to its fine powdery form, nZVI has limited filed applications. The efforts to overcome this shortcoming by immobilizing nZVI on a supporting material have been made. This study investigated the differences of resin-supported nZVI's characteristics by changing the preparation methods and evaluated its reactivity. The borohydride reduction of an iron salt was proceeded in ethanol/water solvent containing a dispersant and the synthesis was conducted in the presence of ion-exchange resin. The resulting material was compared to that prepared in a conventional way of using de-ionized water by measuring the phyrical and chemical characteristics. BET surface area and Fe content of nZVI-attached resin was increased from $31.63m^2/g$ and 18.19 mg Fe/g to $38.10m^2/g$ and 22.44 mg Fe/g, respectively, by switching the solution medium from water to ethanol/water with a dispersant. The reactivity of each material was tested using nitrate solution without pH control. The pseudo first-order constant of $0.462h^{-1}$ suggested the reactivity of resin-supported nZVI prepared in ethanol/water was increased 61 % compared to that of the conventional type of supported nZVI. The specific reaction rate constant based on surface area was also increased. The results suggest that this new supported nZVI can be used successfully in on-site remediation for contaminated groundwater.