• Analytical Science and Technology
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• 제18권1호
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• pp.66-73
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• 2005

In this study, we investigated the gas chromatography (GC) and pulsed flame photometric detection (PFPD) system for the analysis of four major reduced S compounds including hydrogen sulfide ($H_2S$); methyl mercaptan ($CH_3SH$); dimethyl sulfide (DMS); and dimethyl disulfide (DMDS) contained in environmental samples. To analyze these compounds in high concentration range (above ppb level), we developed a high mode analytical setting with the loop-injection system. By contrast, we also established a low mode setting for the analysis of low concentration samples (ppt-level samples from ambient air) by the combination with thermal desorption unit (TDU). Comparative analysis of both settings revealed that relative detection properties of four S compounds are systematic enough. The results of high mode analysis indicated that the patterns were systematic among S compounds: $H_2S$ exhibited the lowest sensitivity, while DMDS showed the strongest one. The results were also compared in terms of sensitivity reductions for all compounds by dividing slope ratios between low and high mode system. Although low mode system exhibited significant reductions on the order of a few tens times, their detection characteristics were highly consistent as it was shown in the high mode setting. To learn more about absolute and relative relations between two different modes of S analysis, future studies may have to be directed to cover more complicated nature of GC/PFPD performance.

• Analytical Science and Technology
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• 제17권2호
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• pp.145-152
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• 2004

In this study, analytical characteristics of S gas detection technique were investigated against four major reduced S compounds (including hydrogen sulfide; methyl mercaptan; dimethyl sulfide (DMS); and dimethyl disulfide (DMDS)). To analyze such properties, an analytical system was constructed by combining the GC/PFPD system with the loop injection method. The results of our analysis indicated that response behavior of S gases differs greatly between compounds; H2S exhibited the weakest sensitivity of all compounds, while DMDS with two S-atom compounds the strongest sensitivity. To learn more about their response behavior on GC/PFPD method, their calibration patterns were compared using the three arbitrarily set concentration ranges of low, intermediate, and high. The results showed that calibration patterns of each compound are distinguished because of different factors. There was a line of evidence that calibration of $H_2S$ was affected noticeably by adsorptive loss within the system, whereas those of DMS and DMDS were influenced most sensitively by such factor as the linearity response at a given PMT voltage setting. The overall results of our study suggest that quantification of malordorous S compounds require a better knowledge of compound-specific response behavior against GC detection.

• The Journal of Korean Medicine
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• 제30권2호
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• pp.79-87
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• 2009

Objective: This study assessed five respective herbs in Cheonggugamrosu (CGGRS) for ability to inhibit malodor in vitro. Methods: We used malodor modeling of the salivary sediment system. Incubation mixtures were prepared with sediment at 16.7% (v/v), amino acids (cysteine and tryptophan) at 6mM and either herb extract at 1% (w/v) or water as control. Mixtures were incubated at $37^{\circ}C$ and odor was monitored organoleptically and for volatile sulfur compounds with the Halimeter. Indole/skatole was determined by Kovac's colorimetric method. Results: Two of the herbs, Caryophilli Flos and Glycyrrhizae Radix, had inhibitory effect on malodor generation. Both of them significantly reduced VSC, organoleptic odor and indole/skatole formation (p<0.05). Conclusions: We found Caryophilli Flos and Glycyrrhizae Radix played a main role in CGGRS. Both herbs have potential as effective anti-malodor agents and this suggests they are worthy of further exploration.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.117-120
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• 2007

Fuel cells are currently attracting tremendous interest because of their huge potential in stationary applications, in terms of substantiality of our energy use. They also offer environmental advantages, combining significantly higher efficiency with very much lower emission of SOx, NOx, and residual hydrocarbons, and significantly reduced $CO_{2}$ emissions compared to conventional power generation. The molten carbonate fuel cell (MCFC) was introduced from Fuel Cell Energy(FCE), which the one MCFC was operating by LNG and the other was operating by ADG. The ADG contains normally CH4, CO2 and various impurities such as sulfur compounds and siloxanes. Using the ADG as a fuel, MCFC have the potential to provide significant environmental and economic benefits. However, such impurities would be harmful to fuel cells. In this work, a purification process for the ADG was designed and installed in order to utilize the gas as a fuel for MCFC.

• Current Research on Agriculture and Life Sciences
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• 제32권2호
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• pp.63-66
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• 2014

The effects of a newly developed flower thinning formulation (FTF) on the vitality of the honey bee Apis mellifera were examined by measuring the activities of various digestive enzymes in adult worker bees. First, direct spraying of the FTF solution did not cause any behavioral changes or lethal effects for the honey bees based on 24 h observation. Second, oral ingestion of a sugar solution containing the FTF did not produce any significant change in the activities of amylase, proteinases, lipase, or acetylcholine esterase (AChE) in the worker bees 6 h or 24 h after treatment. Meanwhile, a commercial formulation containing sulfur compounds showed slightly reduced activities for several digestive enzymes and AChE, although no behavioral disturbance. Thus, the results of the present study suggest that the FTF is not toxic for honey bees, in terms of contact and ingestion. Therefore, this newly developed FTF can be used for flower thinning without any detrimental effects on pollinating insects.

• Analytical Science and Technology
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• 제25권6호
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• pp.447-459
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• 2012

In this study, the emission characteristics of volatile and odorant species released from salted meat product (Spam) was investigated as a function of time. Gas samples released from Spam samples were analyzed for volatile organic compounds (VOC) and sulfur compounds (RSC) at five different times for the elapsed (E) days of 0, 1, 3, 6, and 9 (E-0 to E-9) by GC/MS and GC/PFPD system, respectively. Results indicated that reduced sulfur, aldehyde, and ketone groups were the dominant odorants. Especially, hydrogen sulfide was the predominant in concentration and odor activity value (OAV) during the fresh stage. Its concentration was 1465 ${\mu}g/m^3$ (60.0% of the total mass) in E-0 and 455 ${\mu}g/m^3$ (28.0%) in E-1, while its OAV was 19.4 (78.3%: E-0) and 6.02 (41.7%: E-1). On the other hand, the concentration of acetone showed the maximum values in the decaying stage (E-3: 451 (43.2%), E-6: 369 (64.2%), and E-9: 1150 ${\mu}g/m^3$ (70.2%)). Furthermore, the concentration of 2,3-butanedione was also detected considerably from decaying sample (E-3: 17.6 (1.68%), E-6: 16.1 (2.80%), and E-9: 179 ${\mu}g/m^3$ (10.9%)). However, OAV of acetone was insignificant (<0.01%) in the decaying stage, while that of 2,3-butanedione was relatively high in the range of 1.14-11.6 (14.5-76.2% of ${\Sigma}OAV$). It thus confirmed that the major odorant groups generated from Spam samples changed with the progress of decay such as sulfur (fresh stage), aldehyde (intermediate stage), and ketone compounds (decaying stage).

• Asian Journal of Atmospheric Environment
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• 제11권1호
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• pp.15-28
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• 2017

The adsorptive removal properties of synthetic A4 zeolite were investigated against a total of 16 offensive odors consisting of reduced sulfur compounds (RSCs), nitrogenous compounds (NCs), volatile fatty acids (VFAs), and phenols/indoles (PnI). Removal of these odors was measured using a laboratory-scale impinger-based adsorption setup containing 25 g of the zeolite bed (flow rate of $100mL\;min^{-1}$). The high est and lowest breakthrough (%) values were shown for PnIs and RSCs, respectively, and the maximum and minimum adsorption capacity (${\mu}g\;g^{-1}$) of the zeolite was observed for the RSCs (range of 0.77-3.4) and PnIs (0.06-0.104), respectively. As a result of sorptive removal by zeolite, a reduction in odor strength, measured as odor intensity (OI), was recorded from the minimum of approximately 0.7 OI units (indole [from 2.4 to 1.6]), skatole [2.2 to 1.4], and p-cresol [5.1 to 4.4]) to the maximum of approximately 4 OI units (methanethiol [11.4 to 7.5], n-valeric acid [10.4 to 6.5], i-butyric acid [7.9 to 4.4], and propionic acid [7.2 to 3.7]). Likewise, when removal was examined in terms of odor activity value (OAV), the extent of reduction was significant (i.e., 1000-fold) in the increasing order of amy acetate, i-butyric acid, phenol, propionic acid, and ammonia.

• Analytical Science and Technology
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• 제23권4호
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• pp.347-356
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• 2010

Emission characteristics of major offensive odorants were investigated using odor samples collected from two urban stormwater catch basins with highly contrasting environmental conditions. A total of 6 major offensive odorants ($H_2S$, $CH_3SH$, DMS, DMDS, $CH_3CHO$ (AA), and $NH_3$) were measured. For this comparative analysis, odor intensity (OI) of all odorants was derived from their concentration data via empirical equations introduced by Nagata. Both the absolute magnitude of odorant concentrations and their OI values were used concurrently to evaluate the occurrence pattern of each individual odorant. According to our analysis, RSCs including $CH_3SH$, $H_2S$, and DMS tend to exhibit the highest odor strengths among all 6 compounds investigated. The overall results of our study suggest that the emissions of major offensive odorants from urban stormwater catch brains can be explained at least partially by the temporal trend of human activity.

• Korean Journal of Microbiology
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• 제32권4호
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• pp.252-257
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• 1994

A new hydrogen sulfide-oxidation bacterium, Thiobacillus sp. was isolated from waste coal mine water around Hawsun in Chunnam province. The isolate was motile gram-negative rod shape, formed spore and grew up to be aerobically facultative chemolithotroph by using energy released from the oxidation of reduced inorganic sulfur compounds. It could assimilate various kinds of organic compounds and grew well upon thiosulfate-supplemented basal medium. To the lelvel of 32 mM in thiosulfate concentration, thiosulfate in itself was utilized as energy source for growth. However, from those of the higher concentration than 32 mM, thiosulfate functioned specifically as the substrate inhibitor rather than as the energy source. It was found that the optimum thiosulfate concentration for growth was 32 mM. The G+C content of the DNA was 65.0 mol%. The isolate had 16 : 1 + 17$_{cyc}$, 16 : 0 as their major non-hydroxylated cellular fatty acids, 3-OH 12 : 0 as a hydroxylated fatty acid and also contained unidentified $C_{18}$ branched fatty acid. The ubiquinone system in the respiratory chain was Q-9. Based on the physiological and biochemical characteristics, the isolate was assigned to a novel species of the genus Thiobacillus sp. iw.

• Journal of Oral Medicine and Pain
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• 제36권4호
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• pp.245-252
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• 2011

The aim of this study is to clinically evaluate the effect of a mouthwash containing cetylpyridinium and zinc chloride on reduction of morning oral malodor in healthy subjects measured by organoleptic measurement and a portable sulfide monitor. A total of 8 healthy non-smoking male volunteers were enrolled in this study of crossover design consisting of two experimental phases. The subjects were instructed to rinse the mouth with 10 mL of the experimental mouthwash containing cetylpyridinium and zinc chloride for 30 seconds at the first phase. At the second phase after a one-week washout period, each subject rinsed with distilled water as a control. All experiments were conducted at around 8:30 a.m. and oral malodor was measured using organoleptic measurement and a portable sulfide monitor just before rinsing with the experimental mouthwash or control (baseline), 1 hr, 2 hrs, and 3 hrs after rinsing. The mouthwash containing cetylpyridinium and zinc chloride reduced morning oral malodor up to 3 hrs after rinsing. Organoleptic score and concentrations of volatile sulfur compounds after use of the experimental mouthwash significantly decreased with time, and the decreases were significantly different between the mouthwash and control. In conclusion, the mouthwash containing cetylpyridinium and zinc chloride is significantly effective on reduction of morning oral malodor in healthy subjects by 3 hrs.