• Bulletin of the Korean Chemical Society
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• v.24 no.9
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• pp.1276-1280
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• 2003

Thermal behavior of bromphenols was investigated by direct pyrolysis at high temperature. The thermal degradation products formed by the pyrolysis of mono-bromophenols (o-, m-, and p-) were identified by gas chromatography-mass spectrometry. During the pyrolysis reactions, several kinds of dioxins and furans were produced, and the relative ratio of pyro-products was dependent on the substituted position of bromine in phenolic structure due to the effect of symmetry and steric hindrance. The formation of dioxins can be explained by the phenoxy radical addition and Br atom elimination at an ortho-carbon site on phenolic structure. On the other hand, the formation of furans can be explained by the ortho-ortho carbon coupling of phenoxy radicals at unsubstituted sites to form o, o'-dihydroxydiphenyl intermediate via its keto-tautomer, followed by $H_2O$ elimination. The pyrolysis temperature has also a substantial effect on the dimerized products quantities but little effect on the type of pyro-products. Moreover, the formation mechanism of pyro-products was suggested on the basis of products identified.

• Bulletin of the Korean Chemical Society
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• v.32 no.10
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• pp.3702-3706
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• 2011

The conformation of a neuropeptide, substance P (SP), in isotropic (q = 0.5) acidic bicelles was investigated using two-dimensional NMR techniques. By the nuclear Overhauser effect (NOE) cross peaks between SP and long-chain lipid molecules SP was probed to bind on the flat surface of the disc-like bicelles. Structural analysis of NMR data indicated that the helical conformation of SP extended to the C-terminal region of Leu10 as well as in the mid-region from Pro4 to Phe8. As compared with the conformations of SP bound on the sodium dodecylsulfate (SDS) or the dodecylphosphocholine (DPC) micelles with curved surfaces, the surface curvature of the membrane mimics was found to be one of the major factors inducing the biologically relevant conformation of SP. The negative surface charge of the membrane is also a key factor inducing both the binding of SP on the membrane and its biologically active structure.

• Toxicological Research
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• v.21 no.2
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• pp.99-105
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• 2005

Photo-mutagenic compounds have been known to alter skin cancer rates by acting as initiators or by affecting subsequent steps in carcinogenesis. The objectives of this study are to investigate the utility of photo-chromosomal aberration (photo-CA) assay for detecting photo-clastogens, and to evaluate its ability to predict rodent photocarcinogenicity. Photo-CA assay was performed with five test substances that demonstrated positive results in photo-carcinogenicity tests: 8-Methoxypsoralen (photoactive substance that forms DNA adducts in the presence of ultraviolet A irradiation), chlorpromazine (an aliphatic phenothiazine an alpha-adrenergic blocking agent), lomefloxacin (an antibiotic in a class of drugs called fluoroquinolones), anthracene (a tricyclic aromatic hydrocarbon a basic substance for production of anthraquinone, dyes, pigments, insecticides, wood preservatives and coating materials) and Retinoic acid (a retinoid compound closely related to vitamin A). For the best discrimination between the test substance-mediated genotoxicity and the undesirable genotoxicity caused by direct DNA absorption, a UV dose-response of the cells in the absence of the test substances was firstly analyzed. All 5 test substances showed a positive outcome in photo-CA assay, indicating that the photo-CA test is very sensitive to the photo-genotoxic effect of UV irradiation. With this limited data-set, an investigation into the predictive value of this photo-CA test for determining the photo-carcinogenicity showed that photo-CA assay has the high ability of a test to predict carcinogenicity. Therefore, the photo-CA test using mammalian cells seems to be a sensitive method to evaluate the photo-carcinogenic potential of new compounds.

• Preventive Nutrition and Food Science
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• v.13 no.3
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• pp.241-244
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• 2008

Methanol extracts were prepared from Z. schinifolium leaf and successively fractionated with chloroform, butanol, and water. The butanol fraction exhibited the highest antioxidative activities. Therefore the butanol fraction was purified and a chemical structure was identified by $^1H-^{13}C-NMR$ spectra, and FT-IR. The isolated antioxidative substance was identified as quercitrin.

• Fire Science and Engineering
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• v.31 no.1
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• pp.81-88
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• 2017

This study analyzed chemical accidents each year according to the status, type of accident, accident place, business size, and chemical substance. The results of the chemical accident investigation were 16 cases in 2013, 27 cases in 2014, 46 cases in 2015, and 23 cases in 2016. According to the type of chemical accident, number of accidents, and casualty accidents, leakage was found to be the major cause. As a result of accidents and casualties caused by chemical accidents, workplaces had the highest numbers in all survey items. An examination of the top 10 accident materials revealed 9 substances to be hazardous chemicals. These materials were accident preparedness substances, and toxic substances.

• Journal of Environmental Health Sciences
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• v.45 no.5
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• pp.465-473
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• 2019

Objectives: A variety of industries handling hazardous chemicals emit odorous substances. Based on the emission characteristics of major odor substances from the results of hazardous chemical substance emissions, we will define basic data for improving the management methods of odorous substances. Methods: A survey of hazardous pollutant emissions for 2010-2016 was conducted through the Pollutant Release and Transfer Register homepage. Eight kinds of designated odor substances (ammonia, hydrogen sulfide, dimethyl disulfide, acetaldehyde, styrene, toluene, xylene, methyl ethyl ketone) provided the study subjects. The status of chemical accidents for the target substances was analyzed using the Chemistry Safety Clearing-house system. Results: From 2010 to 2016, it was found that more than 30% of businesses that emitted odorous substances accounted for more than 50% of the total emissions of the eight substances. Emissions of xylene, toluene, methyl ethyl ketone, and ammonia were found, in that order, and they made up more than 90% of the total emitted. By region, about 70% of odorous substances were emitted in the top-four regions: Gyeongsangnam-do Province, Ulsan, Gyeonggi-do Province, and Jeollanam-do Province. Conclusion: Recently, the amount of chemical emissions has been continuously increasing, including those that can cause odor. Odorous substances can be a serious risk to the lives of local residents. Systematic research is needed for the health protection of residents.

• Journal of the Korean Chemical Society
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• v.13 no.4
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• pp.333-339
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• 1969

Synthesis and chemical properties of 1,4-bisdiazo-2-butene have been studied. 1,4-Bisdiazo-2-butene which was very unstable produced in protic solvents 1,3-butadiene and one unidentified substance instead of ring compounds. The reaction in aprotic solvents remains for further investigations.

• The Journal of the Korea Contents Association
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• v.12 no.5
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• pp.323-330
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• 2012

The purpose of this study was to examine the occurrence level of harmful chemical substance and the riskiness caused by it at university laboratory, which had been faintly interested in safe health management. It measured and analyzed indoor pollutants by academic department targeting K university where is located in Seoul Metropolis for 6 days starting from May 26, 2010. As a result, the appearance of being furnished with MSDS, the appearance of installing the exposure-reduction facilities, and the present status of supplying protective equipment in order to grasp the present status of managing harmful chemical substance at university laboratory were relatively good in management at the Dept. of Chemistry, the Dept. of Physics, and the Dept. of Medical Science, which are basic science laboratories. The activity for managing harmful chemical substance in the Dept. of Dental Medicine and the Dept. of Fine Arts was surveyed to be insufficient. Also, the concentration of formaldehyde and TVOCs(total volatile organic compounds) inside laboratory was detected noticeably highly in the Dept. of Fine Arts compared to other laboratories. The concentration of formaldehyde in a group, which was collectivized by similar academic department, was indicated to be higher in other academic departments including the Dept. of Fine Arts and the Dept. of Life Science, thereby having shown significant difference. The concentration of formaldehyde and TVOCs showed significant difference at the laboratory without installation compared to the laboratory with installation of fume hood. Seeing the above results, it could be known that a whole drop in recognition on influence of chemical upon health leads to being able to increase occurrence level of hazardous factor due to being insufficient in activity of protecting exposure to chemical substance.

• Bulletin of the Korean Chemical Society
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• v.24 no.8
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• pp.1163-1168
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• 2003

The structures of molecular species of galactolipids, such as monogalactosyl diacylglycerol (MGDG) and digalactosyl diacylglycerol (DGDG), isolated from wheat flour have been investigated using negative-ion electrospray ionization (ESI) mass spectrometry interfaced with high performance liquid chromatography (HPLC). According to the result of HPLC analysis, MGDG and DGDG were found to consist of mixtures of five and four molecular species, respectively. The galactolipids have been also analyzed to determine their fatty acid compositions, using HPLC/ESI-MS combined with in-source (or cone voltage) fragmentation. HPLC/ ESI-MS is very useful for one-step analysis of mixtures of galactolipids with a small sample quantity. Especially, the carboxylate anions produced in in-source fragmentations of the negative-ion of each component separated by HPLC provide valuable information on the composition of its fatty acyl chains.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.10
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• pp.1436-1442
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• 2002

In this paper, the effect of the loess and mud of an inorganic substance dyed on cotton knitting fabrics have been studied The structure and chemical composition of loess and mud was analyzed. And the Far-Infrared emissivity and emission power, colorfastness, anti-bacterial properties cotton knitting fabrics dyed with loess and mud were also evaluated. The structure and chemical composion of loess and mud was almost identical structure and to be alike main components were SiO$_2$, Al$_2$0$_3$ and Fe$_2$O$_3$. The cotton hitting fabrics dyed with loess and mud have good colorfastness and anti-bacterial properties. when the dyed fabrics was after-treated with diphenyl ether, the anti-bacterial property were improved. Far-Infrared emissivity and emission power cotton knitting fabrics dyed with loess and mud have very good.