• Environmental Engineering Research
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• v.20 no.2
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• pp.127-132
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• 2015

Perfluorooctane sulfonate (PFOS) and Perfluorooctanoic acid (PFOA) are persistent environmental pollutants, extremely stable, and possibly adversely affect human health. They are widely used in many industries and consumer goods, including sunscreen products. These substances are stable chemicals made of long carbon chains, having both lipid- and water-repellent qualities. The research objectives are (1) to find the most effective method for the preparation of semi-liquid samples by comparing solid phase extraction (SPE) and centrifugation after Pressurized liquid extraction (PLE), and (2) to determine the contamination levels of PFOS and PFOA in waterproof sunscreen samples. All sunscreen samples were analyzed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Sunscreen samples were purchased from domestic and international brands sold in Thailand. Special chemical properties were considered for the selection of samples, e.g., those found in waterproof, sweat resistant, water resistant, and non-stick products. Considering the factors of physical properties, e.g., operation time, chemical consumption, and recovery percentage for selecting methods to develop, the centrifugation method using 2 mL of extracted sample with the conditions of 12,000 rpm and $5^{\circ}C$ for 1 hour after PLE was chosen. The highest concentrations of PFOS and PFOA were detected at 0.0671 ng/g and 21.0644 ng/g, respectively. Even though present concentrations are found at ng/g levels, the daily use of sunscreen products is normally several grams. Therefore, a risk assessment of PFOS and PFOA contamination in sunscreen products is an important concern, and more attention needs to be paid to the long-term effects on human health.

• Korean Journal of Pharmacognosy
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• v.47 no.1
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• pp.62-72
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• 2016

Banhasasim-tang is a well-known traditional Korean herbal formula and has been used clinically for the treatment of gastric disease, including acute and chronic gastritis, diarrhea and gastric ulcers in Korea. In this study, an ultra-performance liquid chromatography-electrospray ionization-mass spectrometer method was developed for the quantitative determination of the 13 marker constituents, homogentisic acid (1), 3,4-dihydroxybenzaldehyde (2), spinosin (3), liquiritin (4), baicalin (5), ginsenoside Rg1 (6), liquiritigenin (7), wogonoside (8), ginsenoside Rb1 (9), baicalein (10), glycyrrhizin (11), wogonin (12), and 6-gingerol (13) in Banhasasim-tang decoction. Separation of the compounds 1-13 was using an UPLC BEH $C_{18}$ ($100{\times}2.1mm$, $1.7{\mu}m$) column and column oven temperature was maintained at $45^{\circ}C$. The mobile phase consisted of 0.1% (v/v) formic acid in water (A) and acetonitrile (B) by gradient elution. The injection volume and flow rate were $2.0{\mu}L$ and 0.3 mL/min, respectively. Calibration curves of the compounds 1-13 were showed with $r^2$ values ${\geq}0.9908$. The limit of detection and limit of quantification values of the compounds 1-13 were 0.04-1.11 ng/mL and 0.13-3.33 ng/mL, respectively. Among the these compounds, the compounds 1-3 were not detected, while the compounds 4-13 were detected in the ranges of $3.20-107,062.98{\mu}g/g$ in Banhasasim-tang sample.

• Korean Journal of Veterinary Research
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• v.60 no.3
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• pp.105-108
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• 2020

These days abattoirs' hygiene of Korea is regulated by Hazzard Analysis Critical Control Point (HACCP). Although 20 years have been left since first HACCP was adjusted in Korea, 12% of abattoirs got inconsistence on evaluations. Food poisoning caused by bacteria feces like pathogenic Escherichia coli and Salmonella has not decreased. These bacteria on meat cross-contaminate at the abattoir. Therefore, field verification of abattoir's critical control point (CCP) and experiments to find alternative ways of the CCP were conducted. The aerobic bacteria were measured before and after high-pressure water based washing process set as CCP in most abattoirs. Four parts of cattle carcasses were selected to apply sponge-swab method. The effects were < 1 log reduction which is not significant. Lactic acid (LC), chlorine dioxide (ClO₂) and slightly acidic electrolyzed water (SAEW) were used to measure the effect of reducing bacteria on beef by the different time. LC has 1.24-2.02 log reduction for aerobic bacteria. ClO₂ has 1.44-1.96 log reduction for aerobic bacteria. SAEW has 1.1-1.91 log reduction for aerobic bacteria. There was significant difference according to concentrations (p < 0.05). This study presents legitimacy for hygiene improvement of CCP by field verification. In addition, chemical disinfectants that can be mechanically applied have better reduction effects of high-pressure washing.

• Journal of the Korean Society for Marine Environment & Energy
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• v.9 no.4
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• pp.187-192
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• 2006

In order to know the biological effect of effluent from shipyard and the adjacent stream water on four organisms (flatfish, rockfish, sea squirt and arkshell) cultured around the shipyard, lethal rate and DNA damage were measured after 48 hr exposure and carried out by a single cell gel electrophoresis, namely comet assay. $LC_{50}$ (48 hr) could not be calculated in any organism 48 hours after exposure to effluent from shipyard and stream water, because all organism showed a lethal rate lower than 20%. Regardless of no acute toxicity, DNA damage of flatfish and rockfish was detected higher in Jang-Pyoung stream than in control, whereas sea squirt revealed higher DNA damage in laundry waste water. From these results, Jang-Pyoung stream seemed to have a relatively higher genotoxicity rather than effluent from shipyard.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.177-182
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• 2012

A new composition of standardized Scutellariae Radix extract (HPO12) was developed for treatment of Alzheimer's disease. For the preclinical pharmacokinetic study of HPO12, a rapid, sensitive, and selective LCMS/MS method was developed and validated for the simultaneous determination of 4 bioactive compounds, baicalein, baicalin, wogonin, and wogonoside. After extraction with ethylacetate, chromatographic analysis was performed on a Thermo $C_{18}$ column ($150mm{\times}2.1mm$, $3{\mu}m$) with a mobile phase consisting of 0.1% formic acid (A) and 0.1% formic acid in 95% acetonitrile (B) by using gradient elution at a flow rate of $250{\mu}L/min$. Analytes introduced to a mass spectrometer were monitored by multiple reaction monitoring (MRM) in positive ion mode. Using $25{\mu}L$ of plasma sample, the method was validated over the following concentration ranges: 25-5000 ng/mL for baicalein, 20-40000 ng/mL for baicalin, 1-1000 ng/mL for wogonin, and 5-10000 ng/mL for wogonoside. The intra- and inter-day precision and accuracy of the quality control samples at the 4 concentrations showed $\leq$ 13.7% relative standard deviation (RSD) and 86.6-105.5% accuracy. The method was successfully applied to determine the concentrations of baicalein, baicalin, wogonin, and wogonoside in rat plasma after intraperitoneal and oral administrations of HPO12.

• Korean journal of applied entomology
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• v.30 no.3
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• pp.219-226
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• 1991

A cytoplasmic polyhedrosis virus isolated from the oriental tobacco budworm, Heliothis assulta (HaCPV), was studied on morphology of the polyhedron and virus particles, analysis of viral protein and nucleic acid, and bioassay of the HaCPV to determine the feasibility of application as a microbial control agent. The shape of polyhedron was hexagonal ranging 0.5-3.7 ${\mu}m$ and the virus particles were icosahedral outline measured 55 nm in diameter. Polyhedral protein was composed of a major polypetide of 24.3 Kd and 5 minor components and virus particle had seven polypeptides ranging in 28.0 Kd-133. 6 Kd by the SDS-P AGE. The genome of virus was segmented with 10 double stranded RNA in the total mol. wt. of 18.08 Md ranging in 0.65 Md -2.79 Md. The $LC_{50}$ values of the HaCPV to the 3rd instar of H. assulta larvae were calculated to $2.895{\times}10^5PIBs/ml$. The $LT_{50}$ values in the concentration of $5.0{\times}10^{6}PIBs/ml$ was 16.4 days.

• Journal of Dental Rehabilitation and Applied Science
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• v.16 no.3
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• pp.211-220
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• 2000

The use of autopolymerizing-cured resin and light-cured resin for direct relining of complete and partial dentures has been popular. This investigation compared the adhesion of autopolymerizing-cured reline resin(Tokuso Rebase, Mild Rebaron) or light-cured reline resin(Mild Rebaron LC, Lighton-U) to metal base or resin base. Cylindrical samples were made from metal($Biosil^{(R)}$) or heat-cured resin(QC-20) and were prepared to produce a flat bonding surface. Cylindrical metal samples were roughened by scratch or by scratch and sandblast and were treated with primer(MR Bond) after scratch and sandblast. And then, liners were prossesed to the cylindrical metal or resin samples according to the manufacturer's recommendations so as to bond metal base or resin base. The specimens were tested in pure tension by using an Instron Univesal testing machine for the four direct reline resins. The results were as follows ; 1. In comparison with tensile bond strength of material relined on resin base or metal base, the case of resin base produced significantly higher tensile bond strength than the case of metal base. 2. Metal surface pretreatment or primer improved the tensile bond strength between the reline resin and the metal($Biosil^{(R)}$) base. 3. The tensile bond strength of Mild Rebaron LC relined on resin base or metal base were similar to those of the other reline resins.

• Journal of Dental Rehabilitation and Applied Science
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• v.16 no.2
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• pp.161-170
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• 2000

The use of autopolymerizing-cured resin and light-cured resin for direct relining of complete and partial dentures has been popular. This investigation compared the adhesion of autopolymerizing-cured reline resin(Tokuso Rebase, Mild Rebaron) or light-cured reline resin(Mild Rebaron LC, Lighton-U) to metal base or resin base. Cylindrical samples were made from metal($Biosil^{(R)}$) or heat-cured resin(QC-20) and were prepared to produce a flat bonding surface. Cylindrical metal samples were roughened by scratch or by scratch and sandblast and were treated with primer(MR Bond) after scratch and sandblast. And then, liners were prossesed to the cylindrical metal or resin samples according to the manufacturer's recomendations so as to bond metal base or resin base. The specimens were tested in pure tension by using an Instron Univasal testing machine for the four direct reline resins. The results were as follows ; 1. In comparison with tensile bond strength of material relined on resin base or metal base, the case of resin base produced significantly higher tensile bond strengths than the case of metal base. 2. Metal surface pretreatment or primer improved the tensile bond strength between the reline resin and the metal($Biosil^{(R)}$) base. 3. The tensile bond strengths of Mild Rebaron LC relined on resin base or metal base were similar to those of the other reline resins.

• The Korean Journal of Malacology
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• v.10 no.1
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• pp.55-63
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• 1994

피조개, Scapharca broughtonii의 개체크기(작은 개체: 1.0-1.3cm, 큰 개체:4-5 cm), 수온(10, 15및 2$0^{\circ}C$), 염분(7,13,19,26 및 32 $\textperthousand$)에 따른 일반적인 대사경향과, 수온 1$0^{\circ}C$와 2$0^{\circ}C$ 그리고 부니 농도 25, 50, 100, 200, 400 600, 800및 1000ppm에서 15일간 노출시키면서 사망률, 산소소비율, 여수율 및 배설률을 측정한 결과는 다음과 같다.1. 일반적으로 피조개의개체 크기는 작은 개체일수록, 그리고 수온이 높을수록 비체중 산소소비율, 비체중 여수율 및 비체중 배설률은 높게 나타났다. 그리고 염분을 제외하고는 산소 소비율과 여수율은 염분농도의 증가에 따라 다소 증가하는 유사한 경향을 보인 반면, 비체중 배설률은 염분농도가 낮아질수록 낮은 양상을 나타내었다. 2. 1$0^{\circ}C$의 경우 작은 개체에서 LC$_{50}$은 557.11 ppm, 큰 개체에서 856.03 ppm이었고, 20%C의 경우, 작은 개체에서의 LC$_{50}$은 274.55 ppm, 큰 개체에서 346.26 ppm이었으며 1$0^{\circ}C$에 비해 2$0^{\circ}C$에서 특히 1000 ppm이상의 농도에서 사망률이 현저히 증가함으로써 부니에 의한 영향은 크게 나타났다.3.에 비해 2$0^{\circ}C$의 고수온구에서 부니의 농도가 높을수록 폐사율은 높게 나타났으며, 1$0^{\circ}C$와 2$0^{\circ}C$의 두 수온구에서 산소소비율과 여수율에 대한 각 농도별 부니의 영향은 유사한 경향을 나타내었다. 특히, 2$0^{\circ}C$에서 사망률이 현저히 증가하기 시작하는 부니농도 100ppm이상에서 산소소비율의 감소가 크게 나타났다. 그리고 암모니아태질소 배설률은 부니농도의 증가에 따라 차츰 증가를 보인후 600ppm이후부터는 다시 감소하는 경향을 보였다.

• 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.