• Korean Journal of Hydrosciences
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• v.2
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• pp.61-68
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• 1991

This study assessed the contribution of heavy metals to total toxicity as well as the presence other toxic compounds before and after adding the chemical P to concurrently conducted bioassay tests of Daphnia magna and P. Phosphoreum. The following conclusions were drawn from this study : With excessive EDTA dosage, a toxicity reduction in Microtox would occur due to a metal-comples being formed. Microtox was far less sensitive than D. magna to heavy metal toxicity, but extended exposure time and reagent could increase the sensitivity.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.6
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• pp.743-757
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• 2006

Volatile organic compound (VOC) has been well-known to Korea since the end of 1990's however, it has not been well documented until now. In this study, present ambient VOC levels, VOC emission sources, and VOC control technologies were reviewed and discussed. In addition, VOC management strategies to cut down ozone concentrations were suggested based on the present VOC database. For anthropogenic VOC reduction, VOC emitted from painting processes and automobiles should be controlled in the first place in large cities such as Seoul, Daegu, and Incheon. For natural VOC management, low emission trees need to be planted in those cities. It is also very significant to keep updating present and future VOC emission inventories for efficient VOC control strategies. As a conclusion, more systematic VOC control road-map based on BACT (best available control technology) needs to be made up. and more economical and efficient VOC control techniques have to be developed under strong national support in order to lower toxic VOC and photochemical oxidant levels.

• Journal of the Korean institute of surface engineering
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• v.32 no.2
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• pp.109-124
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• 1999

A study for replacing methylene chloride for an alternative cleaning agent which can be utilized for cleaning aluminium parts of hard disk drives was carried out at Suwon factory of Samsung Electro-mechanics Co. Ltd. As a result, quite a good cleaning agent was selected through data collection of alternative cleaning agents, their analysis of environment effects and safty factors and testing of their cleaning power. As compared with methylene chloride, the selected cleaning agent has better cleaning power. It is also more environmental-friendly, less toxic and more economical. And the operating cost reduction due to adoption of this alternative cleaning agent in Samsung Electro-mechanics Co. Ltd. was more than ￦l46,000,000 annually without any capital instrument in addition to improvement of environmental and safty conditions in the plant.

• Journal of Pharmaceutical Investigation
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• v.23 no.1
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• pp.27-32
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• 1993

Pharmacokinetic drug interaction between phenytoin and diltiazem was investigated following i.v. administration concomitantly to rabbits. Diltiazem was coadministered at doses of 1, 2 and 3 mg/kg, respectively, with phenytoin (5 mg/kg) to rabbits. Plasma concentration and AUC of phenytoin were increased significantly, but volume of distribution and total body clearance were decreased significantly (p<0.05) at doses of 2 mg and 3 mg/kg of diltiazem. From the results of this experiment, it is desirable that dosage regimen of phenytoin should be adjusted and that therapeutic drug monitoring should be practiced for reduction of side or toxic effect when phenytoin should be administered with diltiazem in clinical practice.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.277.1-277.1
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• 2002

The purpose of this study was to develop PEl-based gene carriers with optimal serum stability and reduced cytotoxicity. PEl is an efficient gene transfer agent with the ability of DNA condensation and endosome escape: however; use of the polymer in vivo is hampered by signigicant reduction in transfection activity by the presence of serum. Chitosan is a non-toxic. biodegradable and biocompatible polymer with hydrophilic functional groups so it may provide a physical stability against challenge by serum proteins. (omitted)

• BMB Reports
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• v.42 no.7
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• pp.462-466
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• 2009

Lipopolysaccharide (LPS), found in the outer membrane of Gram negative bacteria, only exerts its toxic effects when in free form. LPS has three major parts, lipid A, the toxic component, along with a core polysaccharide and O-specific polysaccharide. LPS monomers are known to have molecular masses between 10 to 30 kDa. Under physiological conditions, LPS exists in equilibrium between monomer and vesicle forms. LPS removal by 100 kDa ultrafiltration was more efficient (99.6% of LPS removed) with a low concentration of protein (2.0 mg/ml) compared to a high concentration (20.1 mg/ml). In the presence of different detergents (0.5% Tween 20, 1.0% taurodeoxycholate and 1.0% Triton X-100), LPS removal was more efficient at low protein concentrations (2.0 mg/ml) compared to high protein concentrations (20.1 mg/ml).

• International Journal of Industrial Entomology and Biomaterials
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• v.8 no.2
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• pp.151-159
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• 2004

A detailed evaluation of relative toxicity of fluoride to die 5th instar larvae of PM and NB$_4$D$_2$ races of silkworm and the effects of lethal, sublethal and prevailing levels of fluoride in groundwater on the growth, economic characters and fecundity of the silkworm, Bombyx mori (Lepidoptera: Bombycidae) were studied. The feeding of mulberry, Morus alba leaves treated with lethal and sublethal doses of fluoride to PM and NB$_4$D$_2$ races of silkworms from the beginning of the 5th instar to the end of the feeding period resulted in significant reduction in growth, single cocoon weight, single shell weight, silk index, average filament length, and fecundity when compared to controls. These manges were more pronounced on exposure to lethal dose than sublethal dose and in general, the changes induced by fluoride were more striking in NB$_4$D$_2$ than PM, indicating the greater resistance of PM to higher fluoride levels. Groundwater quality in sericulturally important villages of Karnataka and Andhra Pradesh States has been studied with special reference to the presence of fluoride. On exposure to dose of prevailing levels in the waters of sericulturally important areas, die changes observed on growth, economic characters and fecundity were slightly lower when compared to controls and the decrease was found to be insignificant (P$\geq$0.05). It was concluded that, though minute dose (4.0 ppm) of fluoride did not have any toxic impact, it is toxic at higher concentrations to silkworms.

• Journal of Microbiology and Biotechnology
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• v.17 no.3
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• pp.428-437
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• 2007

The potential for humic substances to serve as terminal electron acceptors in microbial respiration and the effects of humic substances on microbial azoreduction were investigated. The dissimilatory azoreducing microorganism Shewanella decolorationis S12 was able to conserve energy to support growth from electron transport to humics coupled to the oxidation of various organic substances or $H_2$. Batch experiments suggested that when the concentration of anthraquinone-2-sulfonate (AQS), a humics analog, was lower than 3 mmol/l, azoreduction of strain S12 was accelerated under anaerobic condition. However, there was obvious inhibition to azoreduction when the concentration of the AQS was higher than 5 mmol/l. Another humics analog, anthraquinone-2-sulfonate (AQDS), could still prominently accelerate azoreduction, even when the concentration was up to 12 mmol/l, but the rate of acceleration gradually decreased with the increasing concentration of the AQDS. Toxic experiments revealed that AQS can inhibit growth of strain S12 if the concentration past a critical one, but AQDS had no effect on the metabolism and growth of strain S12 although the concentration was up to 20 mmol/l. These results demonstrated that a low concentration of humic substances not only could serve as the terminal electron acceptors for conserving energy for growth, but also act as redox mediator shuttling electrons for the anaerobic azoreduction by S. decolorationis S12. However, a high concentration of humic substances could inhibit the bacterial azoreduction, resulting on the one hand from the toxic effect on cell metabolism and growth, and on the other hand from competion with azo dyes for electrons as electron acceptor.

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1806-1808
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• 2014

We report the successful preparation of gold nanoparticles (Au NPs) using a novel electroreduction process, which is simple, fast, and environmentally friendly (toxic chemicals such as strong reducing agents are not required). Our process allows for the mass production of Au NPs and adequate particle size control. The Au NPs prepared show high biocompatibility and are non-toxic to healthy human cells. By applying radio-frequency (RF) ablation, we monitored the electro-hyperthermia effect of the Au NPs at different RFs. The Au NPs exhibit a fast increase in temperature to $55^{\circ}C$ within 5 min during the application of an RF of 13 MHz. This temperature rise is sufficient to promote apoptosis through thermal stress. Our work suggests that the selective Au NP-mediated electro-hyperthermia therapy for tumor cells under an RF of 13 MHz has great potential as a clinical treatment for specific tumor ablation.

• Korean Journal of Ecology and Environment
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• v.40 no.4
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• pp.560-568
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• 2007

The objectives of this study were to analyze ecological effects on effluents from the Sagok Stream (Chonnam province) as an abandoned mine drainage through necropsy-based health assessments and fish exposure tests, and to conduct In situ field pilot tests for restoration of stream water. Also, we analyzed water quality including general parameters and heavy metals. The tests were performed three times on April 2005, April 2006, and April 2007. Also, we constructed a reactor facility in the outflowing point of the abandoned mine for the remediation of AMD wastewater. In lab test, death rates in all three treatments were ${\geq}50%$ in the experiments. Necropsybased fish tissue assessments using the Health Assessment Index (HAI), indicated that the most frequently damaged tissue was liver (average: 20.8). Values of Health Assessment Index were lower in the control than any other treatments of T1, T2, and T3 and three treatments showed a distinct toxicity impacts by the AMD. In situ lethal test, concentration of Fe, Al and Zn decreased particularly by 85%, 99% and 94%, respectively through the disposal facility. Values of pH, ranged from 3.1 to 7.0, increased by 2.3 fold (mean=5.1) along with the reduction of metal contents. All fishes in P1 cage died 100% on 3 days later after the experimental setting, while all fishes in the P6 died 100% on 9 days later. Overall, these results evidently provide a key methodology for pilot test using the disposal facility and also clarify the toxicity of AMD once again, so this approach used in the pilot facilities here may reduce the acidic and toxic effects in the abandoned mining drainage.