• 한국안전학회지
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• 제21권3호
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• pp.53-58
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• 2006

Following a Mediterranean fruit fly outbreak in South Australia, a bait spray program involving the pesticides like malathion(MAL) was carried out. During the application, dermal exposure was considered for the pest controllers wearing PVC gloves. However there is a lack of information about PVC glove performance like break through times and permeation rates with MAL, therefore, a new analytical method for HPLC-UV was developed. A standard permeation test cell was used in this study. From the results of this study, more than 96% solubility of MAL was provided at 30% isopropyl alcohol in distilled water as a collecting media. However, there was significant decomposition of MAL when the solutions were kept at over $50^{\circ}C$ for 2-3 hours. As a mobile phase, 50% acetonitrile water solution (pH 6.0) gave the greater sensitivity compared with other compositions of acetonitrile solution. The arm section of the gloves had shorter breakthrough times and higher permeation rates compared with the palm. There was no malathion solution breakthrough up to 24 hours using the 1% MAL working strength solution. When the temperature was changed from $22{\pm}1^{\circ}C\;to\;37{\pm}1^{\circ}C$, the breakthrough times were decreased by 14.5% on palm and 37.5% on arm, and permeation rates were increased significantly. The findings of this study indicate that further investigations on used gloves, periods of use and varying working conditions like tasks and seasons should be carried out to assess potential worst case scenarios.

• Journal of Microbiology and Biotechnology
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• 제8권6호
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• pp.656-662
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• 1998

To make a distinction between the influence of the dielectric constant and of methanol concentration on trypsin-catalyzed hydrolysis and methanolysis at $0^{\circ}C$, a model reaction of $N^u$-benzyloxycarbonyl-L-lysine p-nitrophenyl ester with water-methanol mixtures was chosen and a kinetic study done. The $k_{cat}$ values increased with methanol concentration, in a linear manner whereas $K_{M}$ values increased in a log-linear fashion. However, the $k_{cat},$_{M}$ ratio increased at lower methanol concentrations than 30% and then began to decrease at higher concentrations. The decrease in $k_{catK_M}$observed at higher than 30% methanol concentrations is attributed to the hydrophobic partitioning effect on substrate binding. On the other hand, the increase in $k_{catK_M}$ in the 0~30% methanol concentration range seems to be due to the effect of nucleophilic cosolvent on $k_{cat}$ and of the dielectric constant on $k_m$. This explanation was verified by measuring the effect of varying the dielectric constant of the medium on kinetic constants with isopropyl alcohol chemically unrelated to the enzyme reaction as the methanol concentration is maintained at a constant level. Therefore, we conclude that the effect of increasing the methanol concentration in the model reaction on the kinetic parameters $k_{cat \;and\;{K_M}}$ is caused by changes in both the nucleophilicity and the dielectric constant of the medium. Based on product analysis, the increase in $k_4, k_3$by decreasing the temperature can be accounted for by the suppression of hydrolytic reactions. This observation indicates that the nucleophile is favored by low temperatures. There was no loss of trypsin activity over a 10 h period in 60% methanol concentration at $pH^＊\; 5.5,\; 0^{\circ}C$.EX>.

• Environmental Analysis Health and Toxicology
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• 제9권1_2호
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• pp.37-51
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• 1994

To evaluate the genotoxicities of workers exposed to glue and glue cleaning solution, ambient air monitoring of working place, animal study and human monitoring were carried out. By GC-MS analysis, air samples collected from shoesmaking plant were found to be toluene, xylene, cyclohexane, n-hexane, methyl ethyl ketone, trichloroethylene, butylacetate, isopropyl alcohol. Glue and glue cleaning solution from shoesmaking plant were applicated topically to the CD-1 mice. DNA was isolated from skin 24 hr following the application and analysed for DNA-adducts using the nuclease $P_1$version of $^{32}$P-postlabelling assay. RAL (Relative Adduct Labelling, adducts$10^8$ nucleotides) was significantly increased in a dose-dependent manner in the glue cleaning solution treated mice skin. Peripheral blood DNA-adducts of workers exposed to glue and glue cleaning solution were also analysed by the same method, but there were not significant differences in the peripheral blood DNA-adducts level between exposed and control workers. In addition, glue cleaning solution from shoes factory was evaluated for mutagenicity in the Salmonella plate incorporation assay using strains TA 100 and TA 1535 in the presence and absence of Arochlor 1254-induced rat liver S$_{9}$. There was evident mutagenicity for cleaning solution in TA 100 regardless of $S_9$, but TA 1535 showed positive only in the absence of $S_9$when predicted by Stead model of mutagenicity prediction (p=0.0000). The urine concentrates from workers and controls were also assayed for mutagenicity towards strain TA 100 of Salmonella typhimurium in the presence of $S_9$ using Kado's microsuspension assay, but their mutagenic activities were not found to be significant. These data suggest that shoesmaking workers are exposed to genotoxic compounds and need to be monitored by testing the mutagenicity of human urines. However, $^{32}$P-postlabelling application requires further validation for the routine monitoring of human exposure.osure.

• Journal of Pharmaceutical Investigation
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• 제33권2호
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• pp.129-133
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• 2003

In order to evaluate the effects of vehicles and penetration enhancers on skin permeation of apomorphine, the skin permeation rates of apomorphine from vehicles of different composition were determined using Franz diffusion cells fitted with excised rat skins. Solubility of apomorphine in various solvents was investigated to select a vehicle suitable for the percutaneous absorption of apomorphine. The solvents used were propylene glycol (PG), $Transcutol^{\circledR},\;Labrasol^{\circledR},\;Labrafac hydro WL^{\circledR},\;Labrafil WL 2609 BS^{\circledR}$ and isopropyl alcohol. Even though permeation rates of apomorphine from each vehicle were low $(0.008-0.36\;{\mu}g/cm^2/hr)$, the combination of PG and $Labrafac^{\circledR}$ increased it significantly. The permeation rates of apomorphine from $PG/Labrafac^{\circledR}$ mixtures increased as the volume fraction of PG in the mixture increased. The maximum permeation rate of $18\;{\mu}g/cm^2/hr$ was achieved at 30% of PG, which decreased with further increase of PG fraction. A series of fatty acids, alcohols and monoterpenes were employed as penetration enhancers. Incorporation of each enhancer in the $PG/Labrafac^{\circledR}$ (30:70) mixture at the level of 10% improved the skin permeation significantly. The highest permeation rate, $117\;{\mu}g/cm^2/hr$, was attained with myristic acid.

• 한국응용과학기술학회지
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• 제6권2호
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• pp.11-19
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• 1989

In order to fractionate sardine oil by different solvents for an effective use of fish oil being subjected to the limit of use, an attempt was to investigate the proper solvents, ratios and fractionation time. The results of the study were as follows: 1. The proper solvent of fractionation using ethanol, isopropyl alcohol, acetone, and hexane was ethanol, and its optimum ratio was 2:1 (ethanol: oil, v/w). The proper time of ethanol fractionation by the ratio (2:1) was 4hr at $10^{\circ}C$, 6hr at $5^{\circ}C$, 8hr at $0^{\circ}C$and 8hr at $-5^{\circ}C$, respectively. 2. In the fractionation by stages using the ratio (2:1) at each temperature, the yield of stearine was 8％ at $10^{\circ}C$ (Fraction I), 32％ at $5^{\circ}C$ (Fraction II), 7％ at $0^{\circ}C$ (Fraction III) and 10％ at $0^{\circ}C$ (Fraction IV), respectively. When ethanol fractionation was undertaken at $5^{\circ}C$ by stages, the yield of stearine (Fraction II) was high. 3. Iodine value of Fraction II was 96.8. This result indicated that the hydrogenation process would be simplified by fractionation. 4. The percentage of the decrease of polyenoic acids from original sardine oil to Fraction II oil was from 30.5％ to 13.5％. The major fatty acids of Fraction II were palmitic and oleic acids and these fatty acids were about 52％ of total fatty acids. Therefore, Fraction II, which remained liquid oil at room temperature because solid fat content was 6.9％ at $20^{\circ}C$, would be used as frying oil.

• Safety and Health at Work
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• 제2권1호
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• pp.39-51
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• 2011

Objectives: This study was designed to evaluate exposure levels of various chemicals used in wafer fabrication product lines in the semiconductor industry where work-related leukemia has occurred. Methods: The research focused on 9 representative wafer fabrication bays among a total of 25 bays in a semiconductor product line. We monitored the chemical substances categorized as human carcinogens with respect to leukemia as well as harmful chemicals used in the bays and substances with hematologic and reproductive toxicities to evaluate the overall health effect for semiconductor industry workers. With respect to monitoring, active and passive sampling techniques were introduced. Eight-hour long-term and 15-minute short-term sampling was conducted for the area as well as on personal samples. Results: The results of the measurements for each substance showed that benzene, toluene, xylene, n-butyl acetate, 2-methoxy-ethanol, 2-heptanone, ethylene glycol, sulfuric acid, and phosphoric acid were non-detectable (ND) in all samples. Arsine was either "ND" or it existed only in trace form in the bay air. The maximum exposure concentration of fluorides was approximately 0.17% of the Korea occupational exposure limits, with hydrofluoric acid at about 0.2%, hydrochloric acid 0.06%, nitric acid 0.05%, isopropyl alcohol 0.4%, and phosphine at about 2%. The maximum exposure concentration of propylene glycol monomethyl ether acetate (PGMEA) was 0.0870 ppm, representing only 0.1% or less than the American Industrial Hygiene Association recommended standard (100 ppm). Conclusion: Benzene, a known human carcinogen for leukemia, and arsine, a hematologic toxin, were not detected in wafer fabrication sites in this study. Among reproductive toxic substances, n-butyl acetate was not detected, but fluorides and PGMEA existed in small amounts in the air. This investigation was focused on the air-borne chemical concentrations only in regular working conditions. Unconditional exposures during spills and/or maintenance tasks and by-product chemicals were not included. Supplementary studies might be required.

• 한국환경과학회지
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• 제18권3호
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• pp.345-353
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• 2009

The purpose of this study is to examine the health of beauty salon workers through the utilization of questionnaires concerning the extent of exposure to organic solvents found in the air of some beauty salons and any resultant symptoms in employees. The subjects were 36 employees from 10 beauty salons who agreed to participate in this study. The degree of exposure to organic solvents in the air of beauty salons was measured from September 1, 2008 to September 30, 2008. A survey of symptoms that occurred due to exposure to these solvents was also performed. The results were as follows: questionnaires were collected and analyzed from a total of 36 subjects. Of these, 28(77.8%) were female and 8(22.2%) were male. The mean age was 29.08. The mean working period was 7.13 years. Sixteen subjects attended programs at universities while 11 went to beauty schools for vocational education. When testing the concentration of organic solvents in the air of beauty salons, the highest value found was Isopropyl alcohol 511.85 ppb followed by butyl acetate, toluene, acetone, xylene, ethyl benzene, styrene, and chlorobenzene. A logistic regression analysis was performed as follows: the point of each factor was the dependent variable while sex, age, drinking, smoking, educational level, work experience, hairdresser's license, and organic solvents were the independent variables. Statistically significant difference (p<0.05) was shown in the hairdresser's license among Factor 1 and in Xylene among Factor 2; however, difference was not shown in the other variables.

• Toxicological Research
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• 제32권4호
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• pp.337-343
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• 2016

We determined the toxicity of mixtures of ethyl acetate (EA), isopropyl alcohol (IPA), methyl ethyl ketone (MEK), toluene (TOL) and xylene (XYL) with half-maximal effective concentration ($EC_{50}$) values obtained using human hepatocytes cells. According to these data, quantitative property-activity relationships (QPAR) models were successfully proposed to predict the toxicity of mixtures by multiple linear regressions (MLR). The leave-one-out cross validation method was used to find the best subsets of descriptors in the learning methods. Significant differences in physico-chemical properties such as boiling point (BP), specific gravity (SG), Reid vapor pressure (rVP) and flash point (FP) were observed between the single substances and the mixtures. The $EC_{50}$ of the mixture of EA and IPA was significantly lower than that of contained TOL and XYL. The mixture toxicity was related to the mixing ratio of MEK, TOL and XYL (MLR equation $EC_{50}=3.3081-2.5018{\times}TOL-3.2595{\times}XYL-12.6596{\times}MEK{\times}XYL$), as well as to BP, SG, VP and FP (MLR equation $EC_{50}=1.3424+6.2250{\times}FP-7.1198{\times}SG{\times}FP-0.03013{\times}rVP{\times}FP$). These results suggest that QPAR-based models could accurately predict the toxicity of polar and nonpolar mixtures used in rotogravure printing industries.

• Archives of Pharmacal Research
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• 제28권9호
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• pp.1086-1091
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• 2005

An analytical method was developed for evaluating the cannabidiol (CBO), cannabinol (CBN), ${\Delta}^9-tetrahydrocannabinol$ $({\Delta}^9-THC)$ level in human hair using gas chromatography-mass spectrometry (GC-MS). Hair samples (50mg) were washed with isopropyl alcohol and cut into small fragments (< 1mm). After adding a deuterated internal standard, the hair samples were incubated in 1.0M NaOH for 10 min at $95^{\circ}C$. The analytes from the resulting hydrolyzed samples were extracted using a mixture of n-hexane-ethyl acetate (75:25, v/v). The extracts were then evaporated, derivatized, and injected into the GC-MS. The recovery ranges of CBD, CBN, and ${\Delta}^9-THC$ at three concentration levels were $37.9-94.5\%$ with good correlation coefficients $(r^2>0.9989)$. The intra-day precision and accuracy ranged from $-9.4\%\;to\;17.7\%$, and the inter-day precision and accuracy ranged from $-15.5\%\;to\;14.5\%$, respectively. The limits of detection (LOD) for CBD, CBN, and ${\Delta}^9-THC$ were 0.005, 0.002, and 0.006 ng/mg, respectively. The applicability of this method of analyzing the hair samples from cannabis abusers was demonstrated.

• 한국산업보건학회지
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• 제7권1호
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• pp.71-85
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• 1997

The purpose of this study was to evaluate concentrations of organic solvent mixtures in air of rotogravure printing workplaces. Qualitative and quantitative analysis of organic solvents contained in the gravure inks used at rotogravure factories had been done. The results obtained were as follows: 1. The gravure inks mainly consist of toluene, methyl ethyl ketone(MEK), and ethyl acetate(EA), and traces of isopropyl alcohol(IPA), xylene, 2-butanol, cyclohexane, cellosolve etc were also contained in them. 2. Thinner used as a diluent consist of toluene, MEK, and EA. 3. Geometric mean concentration of toluene in ambient air were 23.81 ppm at gravure printing of packing material, 42.10 ppm at gravure printing of wallpaper, 16.95 ppm at gravure printing of plastic bottle for beverage and 4.31 ppm at gravure printing of plywood printing or floor covering. Concentrations of toluene in ambient air showed statistically significant difference between types of printing. 4. Concentrations of MEK in ambient air were 12.43 ppm at gravure printing of packing material, 5.47 ppm at gravure printing of wallpaper, 16.78 ppm at gravure printing of plastic bottle for beverage and 16.44 ppm at gravure printing of plywood printing or floor covering. MEK concentrations in ambient air showed no significant difference. 5. Conentrations of EA were 14.30 ppm at gravure printing of packing material, 1.92 ppm at gravure printing of wallpaper and 21.12 ppm at gravure printing of plywood printing or floor covering. EA concentrations in ambient air shown significant difference. 6. Percentage of the workplaces where the ambient air concentration of organic solvent mixtures exceeded the Korean Permissble Exposure Level(KPEL) amounted to 18.03%. 7. Toluene concentrations in ambient air of rotogravure printing workplaces ranged from 0.69 to 156.02 ppm and urinary hippuric acid excretion ranged from 0.10 to $1.32g/{\ell}$.