• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.7 no.2
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• pp.245-263
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• 1997

For twelve solvent thinners, evaporation rates of components were investigated and models to estimate the actual concentration have been evaluated. Also, the current ACGIH TLVs (Threshold Limit Values) for the concentration of organic mixtures have been adjusted. The results of this study are summarized as follows : 1. Airborne concentrations of solvent thinner components were related to their respective vapor pressure (r=0.96). On the other hand, there was no significant relation between the concentrations in the air of the thinner compounds and the original amount in liquid form. 2. Airborne concentrations of each chemical were estimated by temperature at $8.5{\pm}1$, $16.7{\pm}1$ and $31.5{\pm}2^{\circ}C$ with an air velocity of 1.5 m/s. The concentrations were increased by increasing temperature (p<0.05). The percentage of concentrations were proportionate to their respective percentage of vapor pressure. Among the chemicals studied, n-butyl acetate, n-butyl alcohol, m-xylene, p-xylene and o-xylene showed a clear relationship to temperature. 3. Airborne concentration of each chemical was estimated by air velocity at 0.05, 1.50 and 2.50 m/s, with a constant temperature at $17{\pm}2^{\circ}C$. The concentrations were increased by increasing air velocity (p<0.05). The percentage of concentrations were proportionate to their respective percentage of vapor pressure. Among the chemicals studied, n-butyl alcohol, m-xylene and p-xylene showed a clear relationship to velocity. 4. In estimating the concentrations of solvent thinners by temperature and air velocity, ACGIH TLVs for mixtures tended to be larger than the values obtained by ACGIH exposure index. It shows that ACGIH TLVs for mixtures are not adequate for evaluating the airborne concentration of thinners and other organic mixtures. 5. The evaporation rate of the thinners were compared to the theoretical equations of Hummel, Braun and Mackay. The Hummel and Braun methods were close to exposure index but Makay's showed an underestimated value. In order to see the accuracy of each three models, the SSE (Error Sum of Squares) calculated for Hummel's was 1.73, being the closest to the actual values. 6. Present ACGIH TLVs for mixtures are not appropriate evaluate industrial environments. In this study, a correction of TLVs using vapor pressure of respective components was suggested. In order to evaluate the corrected TLVs a paired t-test was performed. There was no significant difference between the exposure index and the concentration over suggested TLVs (p>0.05). Thus, this corrected TLVs seem appropriate in order to evaluate actual industrial workplaces organic chemical concentration in the air.

• Journal of Korean Society for Atmospheric Environment
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• v.26 no.3
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• pp.305-317
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• 2010

In this research, a total of 11 newly designated offensive odorants in Korea in 2008 and 2010 (styrene (S), toluene (T), p-xylene (p-X), methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), butyl acetate (BuAc), isobutyl alcohol (i-BuAl), propionic acid (PA), butyric acid (BA), isovaleric acid (IA), and valeric acid (VA)) were selected as target compounds and analyzed from two types of gutter system in the urban environment. Because of the environmental significance of these compounds as offensive odorants, the results are meaningful enough to explore their behavior and distribution in the urban environmental systems. In the course of this study, samples were collected three times a day from two different gutter systems representing the wet (W) and dry (D) conditions. A large fraction of volatile organic compounds (VOCs) data fell into method detection limit (MDL) range with exceptions of toluene, p-xylene, and methyl ethyl ketone. In contrast, the results of organic fatty acids were distinguished by the relative dominance of butyric acid and propionic acid over others. If the concentration data of all odorants were converted into odor intensity (OI), the results of aromatics, ketones, acetate, and alcohol groups approached zero level. However, odor intensity of organic fatty acids was noticeably higher with the value of 2.8 (on average) from both W and D system, suggesting their potent roles as odorants in gutter system.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.4
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• pp.446-464
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• 2015

Objectives: This study was conducted to evaluate the task-specific hazards of chemicals used by nail technicians in Daegu Metropolitan City. Materials: A total of 30 nail shops located in Daegu City were surveyed to investigate the major tasks and practices performed by nail technicians and the ingredients listed in nail care products used in shops. We also collected instructions for use and material safety data sheets(MSDSs) of nail care products and compared CAS Nos. of ingredients with the lists of chemicals regulated by the Industrial Safety and Health Act(ISHA) and Chemical Substances Control Act(CSCA). Results: A total of 125 chemical ingredients were found in 468 nail care products used at the 30 nail shops. The most frequently found ingredients were ethyl acetate(72%), followed by n-butyl acetate(71.8%), isopropanol(56%), benzophenone(51.1%), nitrocellulose(46.4%) and ethanol(45.3%). Comparing six tasks, the task of manicuring used the most products at 222 products containing 91 ingredients. Among the 125 ingredients, there are 31 chemicals with occupational exposure limits(OEL) designated by the Ministry of Employment and Labor(MoEL), eight categorized as carcinogens, one mutagen and two reproductive toxic chemicals. In terms of carcinogens, formaldehyde was identified as the only confirmed human carcinogen(1A). We found that there was one chemical with a permissible limit, one special management substance, 18 workplace monitoring substances and ten special health diagnosis substances regulated by ISHA. For CSCA, nine poisonous substances, six substances requiring preparation for accidents and one restricted substance were identified. Conclusions: Based on these findings, formaldehyde was identified as one of the chemicals that should most strictly be controlled for the protection of the health of nail technicians and customers. At the same time, it is necessary to distribute materials with detailed hazardous information of nail care products for nail shop technicians.

• Journal of fish pathology
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• v.18 no.3
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• pp.239-245
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• 2005

Galla Rhois was extracted with various solvents such as ethyl alcohol, ethyl acetate, n-hexane, and n-butyl alcohol, and antibacterial activity of the extracts were also tested. The ethyl acetate extracted Galla Rhois showed high antibacterial activities and was the most effective extract, was further fractionated into 8 subfractions with silica gel column chromatography. The subfractions 4 and 5 exhibited an excellent antibacterial activity against Streptococcus iniac KCTC3657.

• Elastomers and Composites
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• v.34 no.4
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• pp.360-365
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• 1999

In this study, the blends of acrylic quaternary polymer (PEBEV) which was co- polymerized from 2-ethylhexyl acrylate (2-EHA), n-butyl acrylate (BA) and ethyl acrylate (EA), vinyl acetate (VAc), and poly(vinyl chloride-co-vinyl propionate) (PVCVP) were prepared by solution blending. Pressure sensitive adhesive (PSA) properties of PEBEV/PVCVP blends were compared with those of PEBEV/poly(vinyl chloride-co-vinyl acetate) (PVCVAc) blends. Compatibility of PEBEV/PVCVP was better than that of PEBEV/PVCVAc. Tackiness of both blend systems were similar, but holding power began to decrease at 15wt% or higher PVCVAc contents in PEBEV/PVCVAc blends. On the other hands, holding power of PEBEV/PVCVP increased as the contents of PVCVP increased. Failure modes of the blends were adhesive failure except 5wt% of PVCVP was blended.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.2
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• pp.152-161
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• 2021

Eisenia bicyclis is known to have secondary metabolites exhibiting various biological activities. In a preliminary study, the n-hexane fraction obtained from the ethanolic extract of E. bicyclis showed higher anti-inflammatory activity than the ethyl acetate and butyl alcohol fractions based on the inhibition of lipopolysaccharide (LPS)-stimulated nitric oxide (NO) production in RAW 264.7 cells. Using this fraction (E. bicyclis hexane fraction, EHF), we investigated the molecular mechanisms underlying its anti-inflammatory effect in LPS-stimulated RAW 264.7 cells. Pretreatment of the cells with up to 50 ㎍/mL EHF significantly inhibited NO and prostaglandin E₂ production as well as their responsible enzyme proteins and mRNAs, in a dose-dependent manner (P<0.05). Similarly, EHF markedly reduced the production of pro-inflammatory cytokines, such as interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α as well as their mRNA levels. Nuclear translocation of nuclear factor-kappa B (NF-κB) was strongly suppressed by EHF treatment. EHF significantly reduced the phosphorylation of mitogen-activated protein kinases and phosphatidylinositol 3-kinase/Akt in LPS-stimulated cells. Moreover, EHF reduced ear edema in phorbol myristate acetate (PMA)-induced mice. These results indicate that EHF contains potent anti-inflammatory compounds, which may be used as a dietary supplement for the prevention of inflammatory diseases.

• Journal of Soil and Groundwater Environment
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• v.14 no.2
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• pp.26-32
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• 2009

In this study, the degradation of BTEX (benzene, toluene, ethylbenzene, xylene) was tested in both (Fe$^{3+}$+chelating agent)/H$_2$O$_2$system [Fe(III) 1 mM, oxalate 6 mM, H$_2$O$_2$ 3%, and pH 6] and UV/(Fe3++ chelating agent)lHzOz system [UV dose 17.4 kWhlL, Fe(III) 1mM, oxalate 6 mM,H$_2$O$_2$ 1%, and pH 6]. The types of chelating agents used in experiments were catechol, NTA, gallic, acetyl acetone, succinic, acetate, EDTA, citrate, malonate, and oxalate and the optimum chelating agent for BTEX degradation was determined. The results showed that acetate was the optimum chelating agent for BTEX degradation in both (Fe$^{3+}$+chelating agent)/H$_2$O$_2$ and UV/(Fe$^{3+}$+chelating agent)/H$_2$O$_2$ system, and UV radiation enhanced the degradation of BTEX with any types of chelating agents. Moreover, UV/(Fe$^{3+}$+chelating agent)/H$_2$O$_2$ system, which chelating agent was acetate, removed effectively mixtures of BTEX and MTBE (methyl tert-butyl ether) when the concentration of both BTEX and MTBE was 200 mg/L, respectively. In this system, BTEX was degraded completely and 85% of MTBE was degraded at the reaction time of 180 min. Therefore, UV/((Fe$^{3+}$+chelating agent)/H$_2$O$_2$ system with acetate as a chelating agent removed not only BTEX but also BTEX and MTBE, effectively.

• The Korean Journal of Food And Nutrition
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• v.14 no.3
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• pp.228-232
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• 2001

Melanin 생선에 관여하는 tyrosinase 유전자의 발현을 억제하는 물질을 탐색하고자 tyrosinase promoter를 지닌 B16 mouse melanoma cell.에 양파 methanol 추출물을 처리한 바 양파 methanol추출물은 10.0$\mu\textrm{g}$/$m\ell$, 100.0 $\mu\textrm{g}$/$m\ell$, 1.0$\mu\textrm{g}$/$m\ell$ 농도에서 대조군에 비해서 약 15%, 23%, 57%의 억제효과를 나타냈으며, 세포생존율은 1.0$\mu\textrm{g}$/$m\ell$, 10.0$\mu\textrm{g}$/$m\ell$, 100.0$\mu\textrm{g}$/$m\ell$ 1.0$\mu\textrm{g}$/$m\ell$의 농동에서 약 126%, 92%, 85%, 64%로서 세포독성이 낮게 나타났다. Ethyl acetate butyl alcohol. 그리고 물 용매 분획물은 tyrosinase 유전자의 발현을 억제하는 효과가 없었지만 methylene chloride용해 분획물은 10.0$\mu\textrm{g}$/$m\ell$과 100.0$\mu\textrm{g}$/$m\ell$의 농동에서 약 87%와35%의 발현율을 나타냄으로써 대조군에 비해 크게 억제하였다.

• Natural Product Sciences
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• v.17 no.4
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• pp.285-290
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• 2011

The rhizome of Alisma orientale Juzep (Alismataceae) has been used as a crude drug for diabetes, edema, inflammation and urinary disturbances in oriental medicine. Recent animal studies have shown that the extract of Alisma orientale rhizome (AOR) can potently lower high levels of serum lipids and improve insulin resistance, which are usually detected in patients and animals with non-alcoholic fatty liver disease. So, we studied the antioxidative effects of AOR extracts and fraction in vitro and their protective effects against acute hepatotoxicity induced by $CCl_4$ in vivo.. We then investigated the effects of each fraction on hepatotoxicity induced by tert-butyl hydroperoxide (t-BHP). DAOR (dichloromethane fraction of the Alisma orientale rhizome) scavenged free radicals and superoxide anions. DAOR protected against $CCl_4$ induced hepatotoxicity. DAOR had hepatoprotective and antioxidative effects against t-BHP-induced hepatotoxicity in HepG2 cells and in rats.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2006.10a
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• pp.166-169
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• 2006

A promising capacitor, which has conformable step coverage and good uniformity of thickness and composition, is needed to manufacture high-density non-volatile FeRAM capacitors with a stacked cell structure. In this study, ferroelectric $Bi_{3.61}Nd_{0.39}Ti_3O_{12}$ (BNT) thin films were prepared on $Pt(111)/Ti/SiO_2/Si$ substrates by the liquid delivery system MOCVD method. In these experiments, $Bi(ph)_3$, $Nd(TMHD)_3$ and $Ti(O^iPr)_2(TMHD)_2$ were used as the precursors and were dissolved in n-butyl acetate. The BNT thin films were deposited at a substrate temperature and reactor pressure of approximately $600^{\circ}C$ and 4.8 Torr, respectively. The microstructure of the layered perovskite phase was observed by XRD and SEM. The remanent polarization value (2Pr) of the BNT thin film was $31.67\;{\mu}C/cm^2$ at an applied voltage of 5 V.