• Bulletin of the Korean Chemical Society
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• v.32 no.4
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• pp.1221-1227
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• 2011

Ethyl pyruvate (EP) is known as a scavenger of reactive oxygen species (ROS) in the body through its role in the donation of diketone groups to metals to form an EP-metal complex. In order to develop a method for the quantification of EP in biological media, a sensitive and specific, high-performance liquid chromatographyelectrospray ionization-mass spectrometry (HPLC-ESI/MS) method is used to determine the EP-alkali metal ion binding species. The analyte was separated on a ZORBOX SB-C8 ($3.5{\mu}m$, $30mm{\times}2.1mm$ I.D.) column and analyzed in selected ion monitoring (SIM) mode with a positive ESI interface using the m/z 255 $[2M + Na]^+$ ion. The method was validated over the concentration range of $0.5-60.0\;{\mu}g$/mL under 1/9 (v/v) of acetonitrile/methanol solvent system with flow rate 0.05 mL/min. The limit of quantification (LOQ) was $0.5{\mu}g$/mL.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.64-64
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• 2011

모발(human hair)은 양모섬유와 마찬가지로 시스틴을 많이 함유하고 있는 섬유상 케라틴 단백질로써, 두부(頭部)를 보호할 뿐만아니라 신체에 필요하지 않는 중금속을 체외로 방출하는 기능을 지닌 신체의 일부분이다. 또한 모발은 미(美)와 관련하여 가장 관심을 가지는 부분이며, 다양한 방법으로 모발에 변화를 주어 신분을 표시하거나 자신의 미적 표현을 하고 있다. 퍼머넌트 웨이브는 모발에 형태학적 변화를 주는 유효한 수단이며, 염색과 탈색 등은 색상 변화를 주는 중요한 수단이다. 본 연구 에서는 모발을 산성염료로 염색할 때 염색성을 향상시키기 위하여 염색보조제로써 벤질알콜 등을 첨가하여 염색할 때 염색된 모발의 염착량, 보습성, 단백질 유출성, 주사전자 현미경 관찰을 측정하여 다음과 같은 결과를 얻었다. 1) 염색시간이 길어지고, 염색온도가 높아질수록 모발에의 염착량은 증가하며, 특히 벤질 알콜을 첨가하여 염색하는 경우에는 빠른 시간내에 염착평형에 도달하고 비교적 낮은 염색온도에서도 높은 염착량을 나타내었다. 2) 이와같은 용매 첨가의 효과는 염액에 계면활성제와 함께 첨가하여 염색하면 나타나지 않았다. 3) 염색시간이 길어질수록 모발의 보습성은 열악해지지만, 벤질 알콜을 첨가하여 염색하는 경우에는 오히려 보습성이 증가하였다. 또한 염색시간이 길어지면 모발의 단백질 유출성은 증가하지만, 벤질 알콜을 첨가하여 염색하는 경우에는 오히려 단백질 유출성이 감소하였다. 이와같은 결과는 벤질 알콜을 첨가하여 염색하는 경우에 모발의 손상이 적다는 것을 의미한다. 4) 모발의 손상정도에 대한 주사전자현미경의 측정결과는 벤질 알콜의 첨가여부에 따라 큰 차이를 보이지 않았다.

• Korean Journal of Pharmacognosy
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• v.32 no.4 s.127
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• pp.292-296
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• 2001

The Radix of Peucedanum japonicum (Umbelliferae) has been used for dispelling wind-damp, headache, chills and wind cold. In order to evaluate to quality of it, the method for the quantitative determination of peujaponiside $(peucedanol\;7-O-{\beta}-D-apiofuranosyl(1{\rightarrow}6)-{\beta}-D-glucopyranoside)$ as standard compound has been developed. Peujaponiside is a major compound of Peucedani Radix. It was analyzed by HPLC using the solvent system of 15% $CH_3CN$. The amount of peujaponiside from Peucedani Radix are in the range 0.14% (n=20).

• Journal of Powder Materials
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• v.24 no.3
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• pp.223-228
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• 2017

Nanopowders provide better details for micro features and surface finish in powder injection molding processes. However, the small size of such powders induces processing challenges, such as low solid loading, high feedstock viscosity, difficulty in debinding, and distinctive sintering behavior. Therefore, the optimization of process conditions for nanopowder injection molding is essential, and it should be carefully performed. In this study, the powder injection molding process for Fe nanopowder has been optimized. The feedstock has been formulated using commercially available Fe nanopowder and a wax-based binder system. The optimal solid loading has been determined from the critical solid loading, measured by a torque rheometer. The homogeneously mixed feedstock is injected as a cylindrical green body, and solvent and thermal debinding conditions are determined by observing the weight change of the sample. The influence of the sintering temperature and holding time on the density has also been investigated. Thereafter, the Vickers hardness and grain size of the sintered samples have been measured to optimize the sintering conditions.

• Journal of Pharmaceutical Investigation
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• v.32 no.4
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• pp.299-303
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• 2002

The oral bioavailability of itraconazole is variable and low in fasting state. This is mainly due to the low solubility of this drug. Bioavailability can be improved by changing the formulation and it is general that the liquid preparations show greater bioavailability than the solid dosage forms such as tablets and capsules do. Benzyl alcohol-water binary mixture showed the excellent solubilizing capacity for itraconazole but the release of the drug from the preparation needs to be enhanced. In this study, various nonionic surfactants and hydrophilic polymers, poloxamers, were screened to investigate their effects on the releasε of itraconazole from the liquid preparations. Poloxamer 407 showed the most enhancing effect on the drug release and the release rate was proportional to thε amount of poloxamer 407 added. A liquid preparation of itraconazole, consisting of benzyl alcohol/water/poloxamer 407 ternary solvent system, releasεd more than 80% of the total drug amount at 5 min and showεd the possibility of a new formulation development.

• Journal of Integrative Natural Science
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• v.10 no.4
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• pp.245-248
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• 2017

The Cu and CuSn/PVP nanofibers were fabricated by electrospinning method by controlling various parameters. The precursor solution was prepared with copper(II) acetate monohydrate ($Cu(CH_3COO)_2$) and tin chloride dihydrate ($SnCl_2{\cdot}2H_2O$), and polyvinylpyrrolidone (PVP) for adjusting viscosity. The fabricated nanofibers were calcined at 873 K in Ar atmospheric environment for 5 hours to remove the solvent and polymer. The morphology and diameter of nanofibers were measured by optical microscopy (OM) with Motic image plus 2.0 program. The components and chemical environment were investigated with X-ray photoelectron spectroscopy (XPS). From the XPS survey spectra, we confirmed that CuSn/PVP nanofibers were successfully fabricated. The XPS peaks of C 1s and N 1s were remarkably decreased after calcination of the nanofibers at 873 K. It implies that the PVP was completely decomposed after calcination at 873 K.

• Tribology and Lubricants
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• v.25 no.2
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• pp.86-95
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• 2009

Adhesion tests were carried out in order to investigate the effect of temperature on the adhesion behavior between a PMMA film and a fused silica lens in the micro scale. For the tests, a microtribometer system was specially designed and constructed. The pull-off forces on the PMMA film were measured under atmospheric condition as the temperature of the PMMA film was increased from 300 K to 443 K and decreased to 300 K. The contact area between the PMMA film and the lens was observed during the test. The adhesion behavior was changed with the change of the PMMA surface state as the temperature increased. In glassy state below 363 K, the pull-off force did not change with the increase of temperature. In rubbery state from 383 K to 413 K, the pull-off force increased greatly as the temperature increased. In addition, the area of contact was enlarged. In viscous state above 423 K, the fingering instability was observed in the area of contact when the PMMA film contacted with the lens. It was also found that the adhesion behavior can be varied with the thermal history of the PMMA film. The residual solvent in the PMMA film could emerge to the PMMA surface due to the heating and reduced the pull-off force.

• Journal of Environmental Health Sciences
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• v.27 no.4
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• pp.85-91
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• 2001

The regulation of Material safety data sheets(MSDS) was required for the chemicals in use in the workplace from July 1976. Under the provisions of the workplace hazardous materials information system, employers in Korea must be provided with accurate and comprehensive MSDS. To examine the reliability of MSDS for organic solvents, 63 organic solvents and MSDS were collected from the workplace of 39 companies located in Kyonggi province. Manufacture\`s MSDS were compared with the actual composition of the collected samples, and further examined the reliability by checking whether the chemicals analyzed were included in the MSDS correctly. 38 solvents were able to analyze their composition by gas chromatography-mass selective detector(GC-MSD). Among them, 28 solvents were incorrect in their composition and contents. In some case, health hazardous or carcinogenic chemicals which were not included in the MSDS were detected from samples. As a result of evaluating whether the MSDS correspond to the regulation required by Industrial Safety and Health Act (ISHA), the information in the MSDS including hazard classification, occupational exposure level, toxicity, regulatory information were incorrectly provided, and some MSDS did not disclose carcinogenic in their MSDS, and some MSDS were not written in the standard format. From this survey, continuous monitoring and promoting correct MSDS, and analyzing the components of the solvents were required to endure the reliability of MSDS for organic solvents.

• Particle and aerosol research
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• v.11 no.4
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• pp.107-113
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• 2015

SBA-16 (Santa Barbara Amorphous) was synthesized over supported $TiCl_4/MgCl_2$. Due to its high surface area and excellent morphological performance, it was expected to form the bi-supported catalytic system and be used for ethylene polymerization. Polymerization of ethylene was carried out at atmospheric pressure using hexane as solvent and triethylaluminium as cocatalyst. ICP, FTIR, DSC, TG-DTA were used to characterize polyethylene and catalyst product. Optimum conditions for ethylene polymerization were found to be 100 mL hexane, Al/Ti molar ratio of 160 and 1 h polymerization at $60^{\circ}C$. The activity of 396.76 kg PE/mol Ti.h.atm was achieved. Melting point of the obtained polymer was in the range of $132-135^{\circ}C$ and the highest degree of crystallization was 46%.

• KSBB Journal
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• v.26 no.1
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• pp.69-77
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• 2011

In this study, poly (L-lactic acid) (PLLA) microparticles containing gemcitabine hydrochloride were prepared by a supercritical fluid process, called aerosol solvent extraction system (ASES), utilizing supercritical carbon dioxide as antisolvent. The influence of process parameters such as temperature, pressure, $CO_2$ and solution flow rate, solution concentration, and feed ratio of drug to polymer on the morphology and characteristics of the microparticles was studied in detail. The gemcitabine-loaded microparticles exhibited a spherical shape with a smooth surface. The entrapment efficiency of gemcitabine increased with increasing temperature, solution concentration and $CO_2$ flow rate and with decreasing drug/polymer feed ratio. The maximum drug loading obtained from the ASES process was found to be about 11%. The ASES-processed PLLA microparticles containing gemcitabine showed a relatively high initial burst due to the presence of surface pores on the microparticles and the poor affinity between drug and polymer.