• Bulletin of the Korean Chemical Society
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• v.17 no.10
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• pp.892-899
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• 1996

In order to elucidate the effect of alkoxy substituent in thexylborane and hence establish their usefulness as hydroborating agent, reactions of alkenes and alkynes with thexylalkoxyborane (ThxBHOR; R=Et, i-Pr, i-Bu, sec-Bu, t-Bu, Ph) were investigated in detail. The reagents readily hydroborated alkenes and alkynes of various structural types at 25 ℃ in excellent regioselectivity. The selectivity increases consistently with increasing steric size of alkoxy substituent. Especially, the selectivity achieved by the sec-butoxy derivative is comparable to that previously achieved by thexylhaloborane-methyl sulfide (ThxBHX·SMe2), the most selective hydroborating agent known.

• Korean journal of food and cookery science
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• v.11 no.2
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• pp.133-139
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• 1995

Solvent extract of homogenates of fresh garlic or pickled garlic was subjected to GC-MS analysis, which showed 30 volatile sulfur compounds for fresh garlic and 20 compounds for processed one. Maior sulfur compounds from fresh garlic extract were identified to be 3-vinyl-[4H]-1,2-dithiin, diallyl disulfide,3,4-dimethylthiophene and methyl allyl sulfide. Meanwhile, the number of volatile compounds from pickled garlic decreased gradually during storage. Diallyl disulfide, methyl allyl trisulfide and diallyl trisulfide were major volatile sulfur compounds from pickled garlic stored for 50 days. It is appeared that the amount of trisulfides in pickled garlic increased gradually during storage, in contrast to the amount of dithiins and monosulfides in pickled garlic decreased.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.3
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• pp.315-319
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• 2003

Bioactive organosulfur phytochemicals were isolated from fresh broccoli using methlylene chloride as an extract solvent and identified by GC/MSD analyses. Major organosulfur phytochemicals of broccoli extract were found to be isothiocyanates, which constitute 40.42% of total phytochemicals. The isothiocyanates from broccoli extract were identified to be 3-butenyl, 4-methyl thiobutyl, 4-methylthio-3-butenyl, 5-methylthiopentyl, 2-phenylethyl, 3-methyl sulfinyl propyl, and 4-methylsulfinylbutyl isothiocyanates, of which major isothio cyanates were 3 butenyl isothiocyanate and 4-methylsulfinylbutyl isothiocyanate, constituting about 38.55% of total isothiocyanates present in the solvent extract. Also, nitrites, corresponding to products from enzymatic hydrolysis of glucosinolates were identified as 4-methylthiobutyl, 5-methyl thiopentyl, 2-phenylethyl and 4-methylsulfinylbutyl nitrile. In addition, three sulfides were identified as dimethyl disulfide, dimethyl trisulfide and dimethyl tetrasulfide.

• Journal of the Korean Institute of Gas
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• v.17 no.4
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• pp.9-17
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• 2013

Butanethiol is known as a typical odorant with hydrogen sulfide, methyl mercaptan, methyl sulfide, but on the physical and chemical properties and biological hazard assessment, including inhalation toxicity data are very scarce. Butanethiol as a colorless transparent liquid, and has physic-chemical characteristics with flash point as $-23^{\circ}C$ and strong fire risk, boiling point $84-85^{\circ}C$, vapor pressure 80.71 mmHg ($25^{\circ}C$), freezing point $-140.14^{\circ}C$. From whole body exposure with SD rats, the $LC_{50}$ is above 2,500 ppm (9.22mg/L), and then it is classified as the acute toxic chemical (inhalation) category 4 according to the governmental notification No. 2012-14.

• Journal of dental hygiene science
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• v.19 no.3
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• pp.162-169
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• 2019

Background: Oral diseases are caused by various systemic and local factors, the most closely related being the biofilm. However, the challenges involved in removing an established biofilm necessitate professional care for its removal. This study aimed to evaluate and compare the effects of professional self and professional biofilm care in healthy patients to prevent the development of periodontal diseases. Methods: Thirty-seven patients who visited the dental clinic between September 2018 and February 2019 were included in this study. Self-biofilm care was performed by routine tooth brushing and professional biofilm care was provided using the toothpick method (TPM) or the oral prophylaxis (OP) method using a rubber cup. Subgingival bacterial motility and halitosis (levels of hydrogen sulfide, $H_2S$; methyl mercaptan, $CH_3SH$; and di-methyl sulfide, $(CH_3)_2S$) were measured before, immediately after, and 5 hours after the preventive treatment in the three groups. Repeated measures analysis of variance test was performed to determine significant differences among the groups. Results: TPM was effective immediately after the prevention treatment, whereas OP was more effective after 5 hours (proximal surfaces, F=16.353, p<0.001; smooth surfaces, F=66.575, p<0.001). The three components responsible for halitosis were effectively reduced by professional biofilm care immediately after the preventive treatment; however, self-biofilm care was more effective after 5 hours ($H_2S$, F=3.564, p=0.011; $CH_3SH$, F=6.657, p<0.001; $(CH_3)_2S$, F=21.135, p<0.001). Conclusion: To prevent oral diseases, it is critical to monitor the biofilm. The dental hygienist should check the oral hygiene status and the ability of the patient to administer oral care. Professional biofilm care should be provided by assessing and treating each surface of the tooth. We hope to strengthen our professional in biofilm care through continuous clinical research.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.1
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• pp.116-122
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• 2012

Volatile flavor compounds derived from four black garlic extracts purchased in a local market were analyzed for the purpose of quality assessment. A total of 68 compounds was detected in samples using solid phase microextraction (SPME)/GC/MSD, and they were mainly sulfur-containing compounds, including three unknown compounds (21), aldehydes (10), furans (7), alcohols (6), aromatic compounds (7), ketones (4), acids (4), nitrogen-containing compounds (3), esters (2), and miscellaneous compounds (4). 2,6-Dimethyl-4-heptanone having a fruity-sweet odor was the most abundant in all of the samples. Six sulfur-containing compounds including allyl sulfide, 4-methyl-1,2,4-thiazole, 1,3,5-trithiane, unknown I (RI 1564), unknown II (RI 1565), and unknown III (RI 1613) were detected in all of the samples and appeared to contribute to the garlic-like odor. Particularly, three aldehydes (3-methylbutanal, benzaldehyde, phenylacetaldehyde), four furans (furfural, 2-acetylfuran, 5-methyl-2-furfural, furfural alcohol), and others (2,6-dimethylpyrazine, acetic acid) formed through a Maillard reaction during garlic aging were detected in all of the samples, and they contributed to the characteristic burnt, sweet, and sour flavors of black garlic extracts.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.4
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• pp.566-571
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• 2002

Volatile flavor compounds in Alaska pollack sik-hae during fermentation at 5$^{\circ}C$ were analyzed by liquid-liquid continuous extraction (LLCE) and gas chromatography/mass spectrometry (GC/MS) methods. Sixty five volatile compounds were detected in Alaska pollack sik-hae during fermentation. These compounds were composed mainly of 11 S-containing compounds, 13 alcohols, 13 acids, 4 aldehydes, 4 ketones, 6 terpenes,4 aromatic compounds and 10 miscellaneous compounds. Among these, 9 S-containing compounds (3-(methylthio)-1-propene, dimethyl disulfide, diallyl sulfide, methylallyl disulfide, methyl-(E) -propenyl disulfide, dimethyl trisulfide, 2 diallyl disulfide isomers and diallyl trisulfide), 2 acids (acetic acid and butanoic acid), 2 ketones (2, 3-butanedione and 6-methyl-5-hepten-2-one) and 2 esters (ethyl formate and ethyl acetate) were significantly increased during fermentation (p<0.05), and these compounds were suspected to affect on the odor of Alaska pollack sik-hae.

• Korean Journal of Food Science and Technology
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• v.47 no.2
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• pp.176-183
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• 2015

To characterize the aroma properties of roasted bulgogi reaction flavor obtained by using a high-temperature reaction apparatus, the volatile flavor and aroma-active compounds were analyzed using simultaneous steam distillation and solvent extraction (SDE)-gas chromatography-mass spectrometry-olfactometry (GC-MS-O). One hundred five volatile compounds were detected in roasted bulgogi reaction flavor using GC-MS. Out of these compounds, furfural was the most abundant volatile compound, followed in order of abundance by 5-methyl furfural, phenylacetaldehyde, and nonanal. Of the volatile compounds identified in roasted bulgogi reaction flavor, 33 aroma-active compounds were detected using GC-O. 2,3-Butanedione and furfural were the most intense aroma-active compounds detected. Other relatively intense odorants included hexanal, octanal, nonanal, undecanal, phenylacetaldehyde, 5-methyl furfural, 2,6-dimethyl pyrazine, and dimethyl trisulfide. These were important aroma-active compounds that contributed to the aroma of roasted bulgogi reaction flavor because of their potency and aroma properties. The concentrations of the aroma-active compounds increased as the reaction temperature increased, whereas those of the sulfide compounds decreased.

• Journal of Environmental Health Sciences
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• v.44 no.2
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• pp.178-187
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• 2018

Objectives: This study evaluated the odor emission characteristics from a sewage treatment plant near an industrial complex area in Daegu City. Methods: Odor samples were collected from March 2017 to December 2017 and analyzed for specified offensive odor substances. The odor quotient and the odor contribution were calculated. Results: Ammonia, methyl mercaptane, hydrogen sulfide, dimethyl sulfide, acetaldehyde, propionylaldehyde, toluene, xylene, and methylethylketone were detected in all samples for monitoring the specified odor compounds. The result of contribution analysis is that hydrogen sulfide made the highest contribution in all processes, followed by acetaldehyde. Conclusion: The major components of odor can be determined by evaluating their degree of contribution to the odor intensity and the concentration of the individual odor component. To increase the effectiveness of odor reduction, rather than addressing high-concentration odor compounds, policies focused on materials with a high odor contribution are necessary.

• Journal of Environmental Science International
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• v.20 no.8
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• pp.953-962
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• 2011

The covered stream of cities are considered an odor source. Also, the public do not want a wastewater treatment plant(WWTP) near their properties due to the emission of odor emanating from such sources, although they play an important role in urban development. The purpose of this study is to analyze the pattern distribution of the odorous compounds from the Nambu WWTP and Youngho stream in Busan. odor sampled four times were analyzed by instrumental analysis method and indirect olfactory method. The kinds of offensive odorous compounds examined are acetaldehyde, propion aldehyde, hydrogen sulfide, methyl mercaptan, dimethyl sulfide and ammonia. Also, Concentration of air pollutants has been calculated by ISCST3 models. At the result of this study, The Nambu WWTP releases sulfur compounds. And the major odorous were hydrogen sulfide (1,475 ppb) and acetaldehyde (95 ppb) at Youngho stream. The stink which residents feel will point out the Nambu WWTP mainly if the odor is removed with the improvement of a Youngho stream. Accordingly, we should pay more attention to appropriate components to processes in odor reducing plan at Nambu WWTP.