• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.36 no.1
• /
• pp.93-97
• /
• 2023

A triboelectric nanogenerator (TENG) is a device that converts mechanical energy into electrical energy, and has been considered as a substitute for continuous power supply due to its high performance, simple structure and eco-friendliness. Recently, it is important to develop a TENG using a non-toxic material in order to use it as a power source for wearable, attachable, and body-embeddable electronics. Here, we developed a human friendly TENG using polyvinyl chloride (PVC) gel containing acetyl tributyl citrate (ATBC), a non-toxic plasticizer. PVC gels were fabricated using various ratios of PVC and ATBC, and optimized by investigating dielectric properties, surface potential, output performance, and durability. The PVC gel based TENG generates output signals of 73 V and 4.3 μA, i.e., a 5-fold enhancement in the output power compared to pristine PVC-based TENG. In addition, the PVC gel can be stretched over 500% of strain. This study is expected to be helpful in the future development of non-toxic wearable TENG.

• Analytical Science and Technology
• /
• v.21 no.5
• /
• pp.392-396
• /
• 2008

Acer tegmentosum is a tree used to treat various liver diseases in Korea. There have been some concern regarding the safety of Acer tegmentosum due to some toxic chemical compounds in its stems. Supercritical fluid extraction (SFE) was employed to develop a removing method of toxic compounds from Acer tegmentosum. The toxic compounds were effectively extracted with ethanol modified supercritical fluid $CO_2$. The optimum condition of SFE was 100 bar of pressure, $40^{\circ}C$ of extraction temperature, 3 mL/min of $CO_2$ flow rate, 0.2 mL/min of modifier (ethanol) flow rate.

• Journal of Soil and Groundwater Environment
• /
• v.22 no.5
• /
• pp.82-88
• /
• 2017

Contaminated sediment can be treated in order to reuse the treated sediment. Even though the chemical criteria are satisfied, the treated sediment could still impose toxic effects. Therefore, this study investigated the changes in the ecological toxic effects of the contaminated sediment from the J region in Singapore after treatment. The contaminated sediment was subject to sequential soil washing and thermal treatment, followed by pH neutralization. Toxic effects of the contaminated and treated sediments were determined by using Vibrio fischeri ($Microtox^{(R)}$), Triticum aestivum (wheat), and Eisenia foetida (earthworm). After treatment, the concentrations of total petroleum hydrocarbons and heavy metals were decreased by 98% and 59-93%, respectively, and satisfied the Industrial Maximum Values of the Dutch Standard, which were used as the remedial goal. The bioluminescence reduction of V. fischeri decreased significantly, and the earthworm survival increased from 0% to 90% after treatment. The germination rate increased from $0{\pm}0%$ to $75{\pm}13%$ after treatment, but the treated sediment may need additional treatment such as nutrient addition for better plant growth. Overall, this study showed that the treatment of the contaminated sediment satisfactorily removed mixed contaminants, and this led to reduction in toxic effects, suggesting improved potentials for reuse of the treated sediment.

• Journal of Society of Preventive Korean Medicine
• /
• v.19 no.3
• /
• pp.103-113
• /
• 2015

Objective : Five most generally adopting basic oriental prescriptions (yookmijihwangtang, ojeoksan, sipjeondaebotang, samultang, bojoongikgitang) samples were collected from 10 oriental hospitals nationwide and the transferring ratio to aqueous phase (TRAP) were calculated. Method : The samples are grounded evenly and the decocted at $120^{\circ}C$ for 12 min on hot plate and then filtered. The concentrations of As, Cd, Co, Cr and Pb in before and after decoction were measure by ICP/MS and the TRAPs were calculated. Results : The concentrations of As, Cr and Pb in the ground samples before decoction were all below criteria level, and TRAP values were also very low (<10%). For Cd, although some ground samples before decoction showed relatively high concentration level compare to the criteria level, because of their low TRAP (~3%), the actual concentrations in the decoction were quite low compare the criteria level. The Co's concentrations in the ground samples before decoction were all relatively low level. However, the TRAP of Co was astonishingly high value of around 40% average. Conclusion : The toxic heavy metal concentrations in the decoction were very low compare to the criteria level. The TRAPs are less than <10% except Co. The toxic heavy metals in the prescriptions are mainly remained in the residue and the only very small fraction may transferred to the decoctions. Therefore the toxicity of the oriental herbal medicine about the toxic heavy metal may be overstressed. The Co's TRAP turned out to be quite high value (40% average). Since the criteria level wes not established yet, the safety of decoctions according to Co was not fully confirmed.

• Korean Journal of Microbiology
• /
• v.47 no.1
• /
• pp.7-13
• /
• 2011

In general, expression of membrane protein in Escherichia coli is very toxic to the host organism, but the mechanism for the toxicity is not clear yet. Expression of human purinergic receptor $P2X_4$ was found to be extremely toxic to the host E. coli. We examined this toxicity by isolation and analysis of less toxic mutant proteins. We could isolate 30 less toxic mutants of $P2X_4$ after hydroxylamine mutagenesis. Western blot showed that all of them produced proteins smaller than the wild type $P2X_4$. DNA sequencing of two largest mutant proteins showed that they were lost its second transmembrane domain. Localization analysis of these mutant proteins showed that they are not in cytoplasmic membrane, but in inclusion bodies. These data showed that inactive truncated $P2X_4$ is not toxic to E. coli and membrane integration and functionality of $P2X_4$ may be needed to show host toxicity.

• Journal of Environmental Science International
• /
• v.20 no.10
• /
• pp.1221-1232
• /
• 2011

We investigated the toxic effects of difenoconazole on the development in the African clawed frog, Xenopus laevis. To test the toxic effects, frog embryo teratogenesis assays using Xenopus were performed. Embryos were exposed to various concentrations of difenoconazole (0-30 ${\mu}M$). $LC_{100}$ for difenoconazole was 30 ${\mu}M$, and the $LC_{50}$ determined by probit analysis was 27.19 ${\mu}M$. Exposure to difenoconazole concentrations ${\geq}$5 ${\mu}M$ resulted in 10 different types of severe external malformation. Histological examinations revealed dysplasia of the eye, heart, liver, somatic muscle, and swelling of the pronephric ducts. The tissue-specific toxic effects were investigated with an animal cap assay. Blood cells were normally induced at a high frequency by mSCF and activin A. However, the induction of blood cells was strongly inhibited by the addition of difenoconazole. Electron micrographs of tested embryos showed the degeneration of somatic muscle and the shrinkage of microvilli on pronephric duct. The gene expression of cultivated animal cap explants was investigated by reverse transcriptase-polymerase chain reaction (RT-PCR). It revealed that the expression of the blood-specific marker(${\beta}$-globin II) and muscle-specific marker (XMA) were more strongly inhibited than the neural-specific marker(XEn2) by the addition of difenoconazole.

• Journal of Environmental Science International
• /
• v.19 no.8
• /
• pp.1001-1012
• /
• 2010

We investigated the toxic effects of tebuconazole on development in the African clawed frog, Xenopus laevis. To test the toxic effects, frog embryo teratogenesis assays using Xenopus were performed. Embryos were exposed to various concentrations of tebuconazole($0-100\;{\mu}M$). $LC_{100}$ for tebuconazole was $100\;{\mu}M$, and the $LC_{50}$ determined by probit analysis was $82.35\;{\mu}M$. The exposure to tebuconazole concentrations ${\geq}40\;{\mu}M$ resulted in 11 different types of severe external malformations including gut dysplasia. Histological examinations revealed various dysplasia in the eye, heart, liver, intestine, somatic muscle, and in the pronephric ducts. The tissue-specific toxic effects were investigated with an animal cap assay. Blood cells are generally induced at a high frequency by the combination of mSCF and activin A, however, the induction of blood cells was strongly inhibited by the addition of tebuconazole. Electron micrographs of tested embryos showed many of multivesicular bodies and dysplasia of photo-receptive cell, however, the somatic muscle degeneration was not severe. The gene expression of cultivated animal cap explants was investigated by reverse transcriptase-polymerase chain reaction and revealed that expression of the blood-specific marker, $\beta$ globin II and muscle-specific marker, muscle actin were more strongly inhibited than the neural-specific marker, XEn2.

• Environmental and Resource Economics Review
• /
• v.15 no.4
• /
• pp.643-672
• /
• 2006

This study has assessed the industrial human toxicity index by means of toxic substances emissions in South Korean industry. The data used in analysis are the 146 kinds of the toxic chemicals emissions and final demands, total outputs in the input-output table. As a results, human carcinogenic index was $11.86198{\times}10^3$ for overall industries, and $0.26360{\times}10^3$ for average. The industries of higher human toxicity index can be ranked as follows: Mother vehicles and parts (7.85033) > Pig iron and crude steel(4.57409) > Primary iron and steel products(4.36668) > Other transportation equipments and parts(3.43293) > Inorganic basic chemical products(2.64379), etc. Such result can be considered as the priority order of regulation based on industrial characteristics, when the demand and industrial policies should be carried out for the deduction fof toxic substances.

• Journal of Microbiology and Biotechnology
• /
• v.12 no.6
• /
• pp.901-908
• /
• 2002

The relationship between the layered structure of granules in UASB reactors and microbial resistance to toxicity was investigated using disintegrated granules. When no toxic materials were added to the media, the intact and disintegrated granules exhibited almost the same ability to decrease COD and to produce methane. However, when metal ions and organic toxic chemicals were added to a synthetic wastewater, he intact granules were found to be more resistant to toxicity than the disintegrated granules, as determined by the methane production. The difference in resistance between the intact and disintegrated granules was maximal, with toxicant concentrations ranging from 0.5 mM to 2 mM for trichloroethylene with toluene and 5 mM to 20 mM for metal ions (copper, nickel, zinc. chromium, and cadmium ions). The augmented COD removal rate by granulation compared to disintegrated granules was also measured in the treatment of synthetic and real wastewaters; synthetic wastewater, $-2.6\%$; municipal wastewater, $2.8\%$; swine wastewater, $6.4\%$; food wastewater, $25.0\%$; dye works wastewater, $42.9\%$; and landfill leachate, $61.8\%$. Continuous reactor operation also demonstrated that the granules in the UASB reactor were helpful in treating toxic wastewater, such as landfill leachate.

• Journal of Sericultural and Entomological Science
• /
• v.35 no.2
• /
• pp.129-133
• /
• 1993

The 44Md plasmid of Bacillus thruingiensis var. kurstaki HD-1(B. t k HD-1) was partially digested with Sau3AI and the fragments were cloned into E. coli HB101 on vector pBR322. Of 2, 950 clones with a recombinant pBR322, only one clone KC1 was determined to have the gene for crystal toxic proteins from the 44Md plasmid of B. t k HD-1 at the BamHI site of pBR322. The recombinant pBR322 was named pKC1 and its molecular size was 12kb. The KC1 produced a protein which was toxic to the silkworm and antigenically similar to the crystal toxic protein of B. t k HD-1. Also, electrophoretic mobility of the KC1 protein was apparently the same as that of the crystal toxic protein of B. t k HD-1.