• Journal of Environmental Health Sciences
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• v.23 no.2
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• pp.98-105
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• 1997

The study on the cytotoxicity of heavy metals was carried out to evaluate the cytotoxic effect of those on mouse L929 fibroblast cell in 96-well microtiter plates. The cytotoxicity was assayed by the neutral red, tetrazolium MTT, total protein, micronuclei test. The cytotoxicity of the heavy metals by neutral red and tetrazolium MTT was showed in order, cadmium > zinc > nickel for the cationic metals tested. The effect of metal-metal interaction on the cytotoxicity showed a marked reduction of cadmium toxicity by zinc, to a lesser degree, by nickel. The amount of total protein in treated group added heavy metals was less than that of the control and treated cadmium alone was less than those of combination with nickel or zinc. At midpoint cytotoxicity values of heavy metals, the frequency of micronuclei on the cell treated heavy metals was more than that of control and treated cadmium alone was more than those of combination with nickel or zinc. From those results, it could be suggested that the heavy metals decreased the viability of mouse fibroblast L929 cells in a concentration-dependent manner and have cytogenic toxic effects, but mixed group decreased the cytotoxic and cytogenic toxicity on L929 cells.

• Journal of the Korean Chemical Society
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• v.43 no.2
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• pp.167-171
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• 1999

An investigation of the interaction of Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Pb(II) and Ag(I) with two N,N'-dibenzylated nitrogen-oxygen mixed donor macrocyclic ligands, has been carried out. Tle log K values for the respective complexes in 95% methanol have been determined potentiometrically. Both ligands have formed stable complex with only Cu(II) and Ag(I) ion. Transport measurements in a bulk liquid membrane system exhibited a very high selectivity of Ag(I) ion over the other metal ions used.

• Journal of the Korean Wood Science and Technology
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• v.35 no.4
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• pp.29-37
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• 2007

To evaluate the effect of carbonization temperature of charcoal on the heavy metal adsorption property, Quercus mongolica wood and Larix kaempferi bark powder (100~60 mesh) were carbonized at between 400 and $900^{\circ}C$ at intervals of $100^{\circ}C$. In the properties of carbonized materials which affect the adsorption ability, pH increased with increasing the carbonization temperature, so that the pHs of wood and bark charcoal carbonized at $900^{\circ}C$ were 10.8 and 10.4, respectively. Also, in both materials, the carbon content ratio became larger as the carbonization temperature was raised. At the same carbonization temperature, carbon content ratio of the bark charcoal tended to be greater than that of the wood charcoal. In case of iodine adsorption which indicates the adsorption property in liquid phase, the wood charcoal showed higher adsorption value than the bark charcoal. From the investigation of adsorptive elimination properties of the charcoals against 15 ppm Cd, Zn, and Cu, the higher the carbonization temperature, the greater elimination ratio was. In comparison, the wood charcoal presented higher elimination ratio than that of the bark charcoal. In the wood charcoals carbonized at higher than $500^{\circ}C$, especially, 0.2 g of the charcoal was enough to eliminated almost 100% of the heavy metal ions. Heavy metal ion elimination ratio of the charcoals depended on the kinds of adsorbates. The effectiveness of adsorbates in adsorptive elimination by the charcoals were in order of Cu > Cd > Zn. This is because the physicochemical interaction between the adsorbate and adsorbent affects their adsorption properties, it is considered that subsequent researches are needed to improve the effectiveness of heavy metal adsorption by the charcoals.

• Korean Chemical Engineering Research
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• v.49 no.4
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• pp.475-479
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• 2011

Chitosan is a natural polymer that has many physicochemical(polycationic, reactive OH and $NH_2$ groups) and biological(bioactive, biocompatible, and biodegradable) properties. In this study, chitosan nanoparticles were prepared using poly-${\gamma}$-glutamic acid(${\gamma}$-PGA) as gelling agent. Nanoparticles were formed by ionic interaction between carboxylic groups in ${\gamma}$-PGA and amino groups in chitosan. Chitosan(0.1~1 g) was dissolved in 100 ml of acetic acid (1% v/v) at room temperature and stirred overnight to ensure a complete solubility. An amount of 0.1 g of ${\gamma}$-PGA was dissolved in 90 ml of distilled water at room temperature. Chitosan solution was dropped through needle into beaker containing ${\gamma}$-PGA solution under gentle stirring at room temperature. The average particle sizes were in the range of 80~300 nm. The prepared chitosan/${\gamma}$-PGA nanoparticles were used to examine their removal of several heavy metal ions($Cd^{2+}$, $Pb^{2+}$, $Zn^{2+}$, $Cu^{2+}$, and $Ni^{2+}$) as adsorbents in aqueous solution. The heavy metal removal capacity of the nanoparticles was in the order of $Cu^{2+}$ > $Pb^{2+}$ > $Cd^{2+}$ > $Ni^{2+}$ > $Zn^{2+}$.

• Fisheries and Aquatic Sciences
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• v.13 no.2
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• pp.112-117
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• 2010

Altered mRNA expression of two metallothionein isoforms (MT-IA and MT-IB) in response to acute heavy metal exposure was examined in mud loach, Misgurnus mizolepis, fry using a real-time RTPCR assay. Sublethal exposure (1 or 5 ${\mu}M$) to Cd, Cr, Fe, Mn, Ni, and Zn resulted in highly variable transcriptional responses of the two MT isoforms to the heavy metal ions, including upregulation, a steady state, and downregulation. Overall, the most potent inducer of both MT isoforms was Cd (up to 6-fold). Another exposure experiment using a series of doses of Cu revealed that the stimulation patterns of the two MT isoforms differed: MT-IA transcription was soon saturated at higher concentrations (about 2-fold at 1-4 ${\mu}M$ of Cu), whereas the activation of MT-IB was more dependent on the treatment dose (increased up to 5-fold at 3 ${\mu}M$). The isoform-specific allotment of constitutive and inducible functions was not as clear in fry as in adult tissues. Coordinated interaction between the MT-IA and MT-IB isoforms was hypothesized based on the finding that MT-IA represented a primary action under 'less stressful' or 'sublethal' conditions, whereas the activation of MT-IB became important under 'more stressful' or 'lethal' circumstances in this species.

• Nuclear Engineering and Technology
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• v.41 no.5
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• pp.723-728
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• 2009

The response property of the CZT detector ($5{\times}5{\times}5\;mm^3$), widely used in photon spectroscopy, was evaluated by considering the charge collection efficiency, which depends on the interaction position of incident radiation, A quantitative analysis of the energy spectra obtained from the CZT detector was also performed to investigate the tail effect at the low energy side of the full energy peak. The collection efficiency of electrons and holes to the two electrodes (i.e., cathode and anode) was calculated from the Hecht equation, and radiation transport analysis was performed by two Monte Carlo codes, Geant4 and MCNPX. The radiation source was assumed to be 59.5 keV gamma rays emitted from a $^{241}Am$ source into the cathode surface of this detector, and the detector was assumed to be biased to 500 V between the two electrodes. Through the comparison of the results between the Geant4 calculation considering the charge collection efficiency and the ideal case from MCNPX, an pronounced difference of 4 keV was found in the full energy peak position. The tail effect at the low energy side of the full energy peak was confirmed to be caused by the collection efficiency of electrons and holes. In more detail, it was shown that the tail height caused by the charge collection efficiency went up to 1000 times the pulse height in the same energy bin at the calculation without considering the charge collection efficiency. It is, therefore, apparent that research considering the charge collection efficiency is necessary in order to properly analyze the characteristics of CZT detectors.

• Journal of Korean Ophthalmic Optics Society
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• v.1 no.1
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• pp.115-118
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• 1996

The study on the cytotoxicities of heavy metals, metal-metal and metal-chelator combinations was carried out to evaluate the cytotoxic effect of those on mouse L929 fibroblasts. The colorimetric assays (NR and MTT) were conveniently carried out in 96-well microtiter plates. The rank order was Cd > Zn Ni > Cr(III) for the heavy metals tested. Examination of the effect of metal-metal interaction on cytotoxicity showed a moderate reduction of cadmium toxicity by zinc. The colorimetric assays were also effectively used to investigate the effect of the chelators, ethylenediamine tetra acetic acid (EDTA) and chitosan. Reduction of heavy metal toxixity by chelator was efficient.

• YAKHAK HOEJI
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• v.23 no.3_4
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• pp.147-152
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• 1979

Experiments were carried out to investigate for the interaction between FAD solution and synthetic resin containers made of polyvinylchloride(PVC), polyethylene(PE), and polycarbonate(PC), and for the effect of glycyrrhizine or malic acid on stabilization of FAD in aqueous solution by accelerated stability analysis. Analysis of FAD was determined by means of spectrometer and by separating by paper chromatography and metal ions were detected by atomic absorption spectrophotometer, which were extracted from containers by means of Food and Additive Regulation Standard. The thermal decomposition of FAD in aqueous solution was pseudo first order reaction and it was inhibited by adding glycyrrhizine or malic into the solution. PVC, PE and PC containers accelerated the decomposition of FAD in solution. It is assumed that bivalent heavy metals in resin containers may catalize the hydrolysis of FAD. The metals detected from the containers were Ca, Zn, Cu, Fe, Pb and Cd. And the total amounts of detected metals from PVC were 6.2mcg/cm$^{2}$, PE, 5.5mcg/cm$^{2}$, and PC, 2.7mcg/cm$^{2}$ which were proportional to the rate constant of FAD decomposition in aqueous solution.

• Bulletin of the Korean Chemical Society
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• v.25 no.6
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• pp.869-872
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• 2004

Newly synthesized 8-hydroxyquinoline based benzothiazole derivative 2 showed a distinctive $Hg^{2+}$-selectivity over other transition metal ions in aqueous solution. The fluorescence emission at 455 nm of 2 was completely quenched upon interaction with $Hg^{2+}$ ions in dioxane-$H_2O$ system (9 : 1, v/v). The selectivity was decreased in the order of $Hg^{2+}\;>>\;Cu^{2+}\;>\;Cd^{2+}\;>\;Pb^{2+}\;{\thickapprox}\;Zn^{2+}\;{\thickapprox}\;Ni^{2+},\;and\;Hg^{2+}$ concentration dependent fluorescence quenching profile was observed in the presence of common interfering metal ions as background. The fluorescence behavior of 2 suggests that the prepared compound could be used as a fluorescent signaling subunit for the construction of new $Hg^{2+}$-sensitive ON-OFF type supramolecular switching systems.

• Journal of Environmental Science International
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• v.2 no.1
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• pp.61-72
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• 1993

Result of this study indicate that two criteria must be met in order to have effective macrocycle-mediated transport in these emulsionsystem. First, one must effective extraction of the post transition metals, $Cd^{2+}$. $Pb^{2+}$ and $Hg^{2+}$ , into toluene membrane. The effectiveness of this extraction is greatest if log K values for the metal-macrocycle interaction is large. Second, the ratio of the log K values for the metal ion-receiving phase to the metal ion-macrocycle interaction must be large enough to ensure quantitative stripping of the metal ion at the toluene phase interface. Control of the first step can be obtained by appropriate selection of macrocycle donor atom, substituents, and cavity radius. The second step can be controlled by selecting the proper complexing agent for inclusion in the receiving phase. The order of the transport, when using the several $A^-$ species such as $SCN^-$, $1^-$, $Br^-$ and $Cl^-$ is the order of the changing degree of solvation for $A^-$ and the transport of the metals is also affected by the control of concentration for receiving species because of solubility-differences. In this study, we can seperate each single metal ion from the mixture of $Cd^{2+}$, $Pb^{2+}$, and $Hg^{2+}$ ions by using the toluene membranes controlled by optimized conditions. Transport of the single metal is also very good, and alkaline and alkaline earth metals as interferences ions did not affect the seperation of the metals in this macrocycle-liquid membrances but transition metal ions were partially affected as interferences for the post transition metal ions.