• Environmental Analysis Health and Toxicology
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• v.21 no.2 s.53
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• pp.173-184
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• 2006

From the harmfulness expectation test conducted through a toxicity anticipation program, methylcyclohexane turned out to be harmful and simulative, but no carcinogenicity was anticipated. In a four-hour acute inhalation toxicity test, the result showed that lethal concentration ($LC_{50}$) was 3,750 ppm (15,054 mg/L), which was identified as a harmful substance on the basis of the harmful substance classification standard $2 of the Industrial safety and health law. methylcyclohexane fell under the category $4(2,500 substance from the GHS standard acute toxicity harmfulness classification. Also, from subchronic inhalation toxicity test that included 6 hours a day, five days a week, and for 13 weeks, we could observe weight, activity, long term weight, blood and blood biochemical influence from the exposure of test substance. No-observed effect level (NOEL) was determined below $100{\sim}400ppm$ inboth male and female. This material falls under the Category 2 ($50{\sim}250ppm/6hours/90days$) in the GHS (Globally Harmonized System) standard trace long-term whole body toxicity repeated exposure, and can be classified as a harmful substance in accordance with the Industrial Safety and Health Law harmful substance standard $NOEL{\leq}0.5mg/L/6hr/90day$ (rat).

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.2
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• pp.146-151
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• 2014

Objectives: Chrysotile is mineralogically distinct from amphiboles, displaying a notably different chemical structure. The thin sheets that form chrysotile fiber lead to the ability of the lung/macrophage system to decompose the chrysotile fibers. This study was performed in order to compare the physicochemical characteristics of Korean asbestos with those of Canadian amphiboles. Materials: An acid solubility test for each test substance was done to compare pH 4.5 and pH 1.2 distilled water. Asbestos fibers which had been placed in acid solutions for five days, five weeks and weeks were analyzed with a transmission electron microscope equipped with an energy dispersive X-ray spectrometer (TEM-EDS). Results: The composition element (Mg) of Korean chrysotile, Korean anthophyllite and Canadian amosite significantly decreased from 5 days and also decreased significantly after 5 weeks and 10 weeks. Only the composition (Mg) of Canadian crocidolite did not change under any conditions. From 5 days, the Mg of Korean chrysotile, Korean anthophyllite and Canadian amosite were significantly lower than before the acid treatment, but there were no changes over time or by the pH of the acid solutions. Particularly after 10 weeks, the composition (Mg) of Korean chrysotile in the pH 1.2 acid solution showed a rapid reduction of 15.86%. Conclusions: Korean chrysotile was very weak in an acid environment, beginning to show significant changes after 5 days. The Mg component rapidly decreased after 10 weeks in the pH 1.2 acid solution.

• Analytical Science and Technology
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• v.33 no.3
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• pp.115-124
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• 2020

Marker pens belong to school things that are controlled by the regulation system called safety confirmation under special act on the safety of products for children with the formaldehyde criteria of 20 mg/kg. With nine marker pens available commercially, formaldehyde in marker pen ink was analyzed by present test standard where marking on a fabric swatch with a pen and extracting the swatch in water and derivatization with Nash reagent followed by UV/Vis spectrophotometeric measurement (Nash-UV/Vis method), giving not detected results or a false positive result in case of a colored water extract. However, the contents of formaldehyde in ink of nine marker pens were determinded to range between 3.2 ~ 93.2 mg/kg with three results above the safety criteria of 20 mg/kg by HPLC/DAD measurements on DNPH derivatives of formaldehyde (DNPH-HPLC/DAD method) in ink dissolved directly in water using an ultrasonic bath. Therefore, the DNPH-HPLC/DAD method with the extraction of ultrasonic dissolving ink in water is proposed as a proper method for analyzing formaldehyde in ink. The proposed method has advantages of lower detection limit and accuracy with colored extracts as well as a simple and fast extraction. The accuracy and precision of this method was estimated to be 90.1 ~ 105.4 % and 0.6 ~ 3.3 %, respectively by spiking tests in the ranges of 20 mg/kg and 40 mg/kg using matrixes such as highlighter pen ink, board marker ink, chalk marker pen ink and painter marker ink.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.359-362
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• 2013

This study was performed in order to assess the risk of earthworm when the picoxystrobin was sprayed in Korean orchard. The acute toxicity ($LC_{50}$) of picoxystrobin active ingredient(99.3%) and soluble concentrate (25%) against earthworm was showed 10.93 mg/kg and 8-16 mg/kg respectively. This earth worm toxicity value means that the picoxystrobin do not show the earthworm risk in present Korean risk assessment system. However, in the test which was simulated the rainfall after spraying, all the earthworm were died in 24 hours. This result indicated that the risk assessment for the earthworm should be considered the weather condition.

• Toxicological Research
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• v.34 no.4
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• pp.343-354
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• 2018

Aluminum oxide nanoparticles ($Al_2O_3$ NPs) are among the most widely used nanomaterials; however, relatively little information about their risk identification and assessment is available. In the present study, we aimed to investigate the potential toxicity of $Al_2O_3$ NPs following repeated inhalation exposure in male Sprague-Dawley rats. Rats were exposed to $Al_2O_3$ NPs for 28 days (5 days/week) at doses of 0, 0.2, 1, and $5mg/m^3$ using a nose-only inhalation system. During the experimental period, we evaluated the clinical signs, body weight change, hematological and serum biochemical parameters, necropsy findings, organ weight, and histopathology findings. Additionally, we analyzed the bronchoalveolar lavage fluid (BALF), including differential leukocyte counts, and aluminum contents in the major organs and blood. Aluminum contents were the highest in lung tissues and showed a dose-dependent relationship in the exposure group. Histopathology showed alveolar macrophage accumulation in the lungs of rats in the $5mg/m^3$ group during exposure and recovery. These changes tended to increase at the end of the recovery period. In the BALF analysis, total cell and neutrophil counts and lactate dehydrogenase, tumor necrosis factor-${\alpha}$, and interleukin-6 levels significantly increased in the 1 and $5mg/m^3$ groups during exposure. Under the present experimental conditions, we suggested that the no-observed-adverse-effect level of $Al_2O_3$ NPs in male rats was $1mg/m^3$, and the target organ was the lung.

• Journal of the Korean Society of Safety
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• v.1 no.1
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• pp.21-26
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• 1986

Gas sensing materials for detecting inflammable gas such as alcohol, propane, acetic acid, carbon monoxide, hydrogen were developed by utiliting $MgO-Cr_2O_3-TiO_2$ system. Between 30$0^{\circ}C$ and 50$0^{\circ}C$, reversible chemisorption becomes dominant and the electrical canduction of P-type semiconductive with the gas chemisorption. The ceramic sensor exhibits a high sensitivity to particular reducing gas such as alcohol, whereas propane and butane have little effect on the resistivity. The time response of adsorption is estimated to be about 20 sec. On the other hand, the desorption process, which corresponds to oxidation due to oxygen adsorption, take more than 60 sec. Thus the ceramic sensor can be used as a alcohol sensor in an ambient aunosphere. As the oxygen concentration is increased from 0.1 to 10 precent($10^3-10^6ppm$), the resistance decreases rapidly but stabilizes at higher concentration.

• Journal of Food Hygiene and Safety
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• v.14 no.4
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• pp.415-421
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• 1999

The flavin-containing monooxygenases (FMOs) (EC 1.14. 13.8) are NADPH-dependent flavoenzymes that catalyze oxidation of soft nucleophilic heteroatom centers in a range of structurally diverse compounds including foods, drugs, pesticides, and other xenobiotics. In humans, FMOl appears to be the predominant form expressed in human fetal liver. cDNA-expressed human FMO and human liver microsomal FMO have been observed to N- and S-oxy-genate nucleophilic nitrogen- and sulfur-containing drugs and chemicals, respectively. In the present study, FMOl can be expressed in the baculovirus expression vector system at level of 2.68 nmol FMOl/mg of membrane protein. This isoform was examined for its capacity to metabolize methimazole to its S-oxide using thiocholine assay. Kinetic studies of its S-oxide by recombinant human FMO1 result in Km of 7.66 $\mu$M and Vmax of 17.79 nmol/min/mg protein.

• Journal of Applied Biological Chemistry
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• v.62 no.4
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• pp.355-359
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• 2019

In vivo micronucleus tests were performed to investigate the mutagenic potential of 4-butylaniline and N-butylaniline, which are used in dye intermediates and organic intermediates respectively. Groups of 5 male ICR mice were treated with vehicle or 4-butylaniline for 2 consecutive days by oral gavage at concentrations of 0 (control), 64, 160, 400, and 1000 mg/kg. Statistically significant and dose-dependent increases were found for micronuclei frequencies in male mice (p <0.05). These results suggest that 4-butylaniline can induce genetic effects in the micronuclei of male mouse bone marrow cells. Based on the positive results obtained in cytogenetic analyses of somatic cells in vivo, Globally Harmonized System of Classification and Labelling of Chemicals Category 2 was assigned. N-butylaniline was administered for 2 consecutive days by oral gavage to male ICR mice at dose of 0 (control), 64, 160, 400, and 800 mg/kg. N-butylaniline tested negative for micronuclei induction in mice, although N-butylaniline was associated with micronucleus induction at the highest dose. Based on the negative results obtained for cytogenetic analyses of somatic cells in vivo, "Not Classified" was assigned.

• Corrosion Science and Technology
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• v.10 no.4
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• pp.136-142
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• 2011

Al alloys have been used widely for commercial and military ships in most ocean countries since mid-1950s, and the value as light metal with high mechanical strength has been proven. As the safety and fuel efficiency of Al ships have improved, she can carry more freight, sail faster and travel longer distances. Furthermore, in the shipbuilding industry, Al alloys are applied as structural materials for ships to various areas including the deck of luxurious cruises, battleships and leisure ships. In addition, Al alloys are being spotlighted as environmental-friendly material as they can be recycled even after end of lifespan. However, Al alloys for ships must be carefully selected after considering corrosion resistance, endurance, strength, and weldability in sea water environment. Al alloys to satisfy these conditions are used widely include 5000 series Al-Mg alloy and 6000 series Al-Mg-Si alloy. Thus, this study selected and evaluated the cavitation characteristics of the 5000 series Al alloys that are used in hulls that directly contact seawater and the 6000 Al alloys that are used in the upper structures of ships. Results of cavitation test with time, weightloss and cavitation rate of 5456-H116 showed the smallest damage among 5052-O, 5456-H116 and 6061-T6.

• Journal of Mushroom
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• v.18 no.4
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• pp.380-386
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• 2020

The study was conducted for the safety evaluation of 320 pesticide residues in 768 Lentinula edodes fruit body samples and 143 L. edodes media samples, which are distributed nationwide in South Korea. The monitoring method was the second of the multi-residue methods in the Korean Food Code. GC-ECD, GC-NPD, and GC-MSD were used as evaluation equipment for analysis. Single-analysis of the target pesticides was performed for mepiquat chloride. Through the analysis of collected L. edodes samples, pesticide residues were detected in total seven cases, including four L. edodes fruit body samples and three L. edodes media samples. The detected pesticide residues were carbendazim, diflubenzuron, fluopyram, and dinotefuran. In this study, carbendazim was detected in three L. edodes fruit body samples and one L. edodes media sample. The detected amount of carbendazim was 0.056, 0.17, 0.043, and 0.09 mg/kg, respectively. The amount of carbendazim in the collected L. edodes samples was detected below the MRLs (maximum residue level). The detected amounts of fluopyram and dinotefuran were 0.068 mg/kg and 0.06 mg/kg, respectively. Two pesticide residues were detected in the medium in one case. Mepiquat chloride was not detected in this study. These results suggested that residual pesticides were detected in a small number of collected L. edodes. However, the PLS for unregistered pesticides MRL was 0.01 ppm; therefore, we have to conduct research on preparing safety standards for mushrooms, including L. edodes.