• Journal of Microbiology and Biotechnology
• /
• v.16 no.9
• /
• pp.1384-1391
• /
• 2006

The signal transduction system is one of the most important devices involved in maintaining life, and many protein kinases are included in the cellular signal transduction system. Finding a protein kinase inhibitor is very valuable, as it can be used to study cell biology and applied to pharmaceuticals. For the efficient and rapid screening of protein kinase inhibitors, two assay systems were combined; the nonradioactive protein kinase assay system that uses an FITC-labeled IRS-2 peptide and the cell-based paper disc assay system that uses Streptomyces griseus as the indicator strain. Among 330 kinds of herb extracts tested, the extract of Dalbergia odorifera exhibited the strongest inhibitory activity in the two assay systems and was selected for further isolation. Based on solvent extraction and many steps of chromatography, seven compounds were finally separated to homogeneity and their structures determined by $^{1}H$ and $^{13}C$ NMR spectroscopies. Four were to be flavonoids and identified as butin ($C_{15}H_{12}O_5$, Mw=272.07), 3'-hydroxymelanetin ($C_{16}H_{12}O_6$, Mw=300.06), liquiritigenin ($C_{15}H_{12}O_4$, Mw=256.07), and 2'-hydroxyformononetin ($C_{16}H_{12}O_{5}$, Mw=284.07). 3'-Hydroxymelanetin inhibited the phosphorylation of the GSK3 protein by Akt to 37% at a concentration of $10{\mu}g/ml$ and showed the strongest cytotoxicity ($ED_{50}<50{\mu}g/ml$) against the human cancer cell line HCT116. Under the same conditions, liquiritigenin also inhibited the phosphorylation of GSK3 by Akt to 26%, and its cytotoxicity against the HCT116 cell line was lower than $100{\mu}g/ml$.

• Journal of the Korean Institute of Gas
• /
• v.19 no.5
• /
• pp.54-60
• /
• 2015

The autoignition temperature (AIT) of a material is the lowest temperature at which the material will spontaneously ignite. The AIT is important index for the safe handling of flammable liquids which constitute the solvent mixtures. This study measured the AITs of n-decane+ethylbenzene system by using ASTM E659 apparatus. The AITs of n-decane and ethylbenzene which constituted binary system were $210^{\circ}C$ and $430^{\circ}C$, respectively. The experimental AITs of n-decane+ethylbenzene mixture were a good agreement with the calculated AITs by the proposed equations with about $11^{\circ}C$ A.A.D.(average absolute deviation).

• Journal of Surface Science and Engineering
• /
• v.34 no.1
• /
• pp.62-67
• /
• 2001

Green technology is being developed up to a point that is feasible not only in an environmental sense, but also in an economical viewpoint. This paper introduces two case studies that applied $CO_2$ technology into nuclear industry. 1) Nuclear laundry : A laundry machine that uses liquid and supercritical $CO_2$ as a solvent for decontamination of contaminated working dresses in nuclear power plants was developed. The machine consists of a 16 liter reactor, a recovery system with compressors, and storage tanks. All $CO_2$ used in cleaning is fully recovered and reused in next cleaning, resulting in no production of secondary nuclear waste. Decontamination factor is still lower than that in the methods currently used in the plant. Nuclear laundry using $CO_2$ looks promising with technical improvements-surfactants and mechanical agitation. 2) $CO_2$ nozzle decontamination : An adjustable nozzle for controlling the size of dry ice snow was developed. Using the developed nozzle, a surface decontamination device was made. Human oils like fingerprints on glass were easy to remove. Decontamination ability was tested using a contaminated pump-housing surface. About 40 to 80% of radioactivity was removed. This device is effective in surface-decontamination of any electrical devices like detector, controllers which cannot be cleaned in aqueous solution.

• Journal of radiological science and technology
• /
• v.40 no.4
• /
• pp.621-626
• /
• 2017

In this paper, an optical dosimetric system for radiation dose measurement is developed and characterized for 100 MeV proton beams in KOMAC(Korea Multi-Purpose Accelerator Complex). The system consists of 10 wt% Ultima GoldTM liquid organic scintillator in the ethanol, a camera lens(50 mm / f1.8), and a high sensitivity CMOS(complementary metal-oxide-semiconductor) camera (ASI120MM, ZWO Co.). The FOV(field of view) of the system is designed to be 150 mm at a distance of 2 m. This system showed sufficient linearity in the range of 1~40 Gy for the 100 MeV proton beams in KOMAC. We also successfully got the percentage depth dose and the isodose curves of the 100 MeV proton beams from the captured images. Because the solvent is not a human tissue equivalent material, we can not directly measure the absorbed dose of the human body. Through this study, we have established the optical dosimetric procedure and propose a new volume dose assessment method.

• Microbiology and Biotechnology Letters
• /
• v.40 no.4
• /
• pp.371-379
• /
• 2012

This study was designed to explore new nutraceutical and cosmetic resources possessing biological activities from the plant kingdom. To fulfill this purpose, we analyzed the anti-oxidative, anti-melanogenic, and anti-inflammatory activities of Zanthoxylum schinifolium extract (ZSE) and its solvent fractions using in vitro assays and cell culture model systems. Three kinds of ZSE treated with methanol, ethanol, and water exhibited potent anti-oxidative activities through DPPH radical scavenging capacity, and inhibited in vitro DOPA oxidation. Furthermore, Z. schinifolium methanol extract (ZSME) inhibited the ${\alpha}$-melanocyte stimulating hormone, which induces melanin contents in B16F10 cells. Its anti-melanogenic activity originates from the inhibition of tyrosinase enzyme activity and melanogenesis related protein expression. Moreover, lipopolysaccharide induced nitric oxide production in the RAW 264.7 cell line was also ameliorated by ZSME treatment in a dose dependent manner. Among the four solvent fractions of ZSME treated with dichloromethane, ethyl acetate, n-butanol, and water, three fractions, except water, showed significant anti-melanogenic and anti-inflammatory activities. Taken together, these results provide important new insights into Z. schinifolium, indicating that it possesses numerous biological activities such as anti-oxidative, anti-melanogenic, and anti-inflammatory activities. Therefore, it may well serve as a promising material in the field of nutraceuticals and cosmetics.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.10 no.1
• /
• pp.179-207
• /
• 2000

Hazardous organic solvents management as prescribed by presidential decree in Korea is reviewed. The status of import, manufacture, and circulation of organic solvents was investigated. Problems inherent in the management of organic solvents in the electroplating, metal degreasing, and dry cleaning industries were discussed. The chemical substance management system in Korea was compared to those of foreign organizations. A walk-through check list was developed and then used to assess the actual conditions and potential hazards of chemical substances in these industries. The questionnaire could be used to develop a chemical management system and protect workers from hazardous substances. Based on the results of the site survey, MSDSs were not integrated appropriately into the workers education and were not readily accessible to employees. In the case of the dry cleaning industry, the new dry cleaning solvent used as a substitute includes a lot of potentially hazardous organic solvents. This research is preliminary. It is recommended that a national survey be performed to better identify the current situation. Because chemical substances are regulated by thirteen laws in seven executive branches, management systems often overlap, resulting in ineffective control. Using the above results, a model for managing chemical substances was developed. This will more efficiently provide MSDS information to workers covered by the presidential decree and allow the construction of a management system database for better cooperation with the executive branches in Korea.

• Microbiology and Biotechnology Letters
• /
• v.20 no.1
• /
• pp.73-78
• /
• 1992

- Enzymatic synthesis of L-tryptophan(Trp) using E. coli tryptophanase has been investigated. In order to reduce the substrate inhibition by indole and to increase the product yield of L-tryptophan three different approaches have been made in this work. First, indole was intermittently fed to the reaction mixture in order to control the indole concentration at lower level. When 15 mM of indole was used as a total amount of substrate, conversion yield of 80% has been obtained with intermittent feeding while only 20% of indole was converted into L-tryptophan by conventional batch operation, The second method employed in this work was the use of cyclohexane-phosphate buffer organic two-phase system. In this system, indole was mainly partitioned into the organic-solvent phase and therefore substrate inhibition was expected to be reduced. L-Tryptophan production in organic two-phase system was, however, unexpectedly lower than that obtained in aqueous buffer solution. As a third method cyclodextrins have been added to the aqueous reaction mixture. It was found that the addition of $\beta$-cyclodextrin enhanced the tryptophan synthesis noticeably while $\alpha$-cycfodextrin showed little effect on tryptophan production.

• Journal of the Microelectronics and Packaging Society
• /
• v.20 no.2
• /
• pp.23-28
• /
• 2013

Microlens array as basic element of the optical system have been fabricated with various focal length (mainly with long focal length) depending on the purpose of application. In this paper, the microlens arrays were fabricated for observing fluorescent images within sol-gel. Though the fluorescent signal is very low, the microlens array can help obtaining clear images through extracting the fluorescent light from sol-gel. We fabricated microlens arrays with short focal length, which can extract the light using photoresist thermal reflow method. In the experiment, the diameter of microlens decreased after thermal reflow because the solvent within the photoresist was vaporized. Therefore, to compensate the shape error by this reduction, microlens diameter in photomask was altered and spin-coat recipe of photoresist were modified.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.40 no.5
• /
• pp.289-296
• /
• 2016

The availability of NMP, a solvent used in the manufacturing process of cathode material for lithium ion battery, depends on importation, and the price remains high because of the monopoly of BASF and ISP. For these reasons, most Lithium ion battery manufacturers reuse NMP after recovering it from the exhaust air in the drying process. In Korea, absorption method is mainly used for recovering NMP from the absorption tower using the hydrophilicity of NMP. However, this system has a few disadvantages, such as low purity (80％) of the recovered NMP and 100％ emission due to high water content of the treated gas. In this study, we develop a hybrid NMP recovery system by combining cooling condensation method with concentration method, by which it is possible to obtain an NMP recovery rate of 99.6％, and a high purity (96.1％) of the recovered NMP.

• Journal of Pharmaceutical Investigation
• /
• v.40 no.4
• /
• pp.255-261
• /
• 2010

Pluronic as pharmaceutical excipients are listed in the US and British Pharmacopoeia. In particular, Pluronics exist as different compositions and display abundant phases as self-assembling into polymeric micelles with various morphologies depending on the aqueous solvent quality, the composition of structure, and hydrophilic-lipophilic balance (HLB). Pluronics were also known as a P-gp modulator, which was exploited as a reversal molecule of multi-drug resistant (MDR) cancers. We selected a lamella forming Pluronic L92 which has high hydrophobicity and relatively long PEO block among L series of Pluronics. The dispersion of L92 showed great size particles and low stability. To increase the stability and to decrease the particle size, secondary Pluronics (F68, F88, F98, F127, P85, P105, and P123) with relatively long PEO chain were added into 0.1 wt% Pluronic L92 dispersion. The stability of binary systems was increased due to incorporated long PEO chain. Their particle sizes slightly decreased to over 200~400 nm and their solubilization capacity of binary systems didn't change except Pluronic L92/P123 mixtures. The L92/P123 systems showed ca. 100 nm sizes and lowest turbidity among the all systems. The solubilization capacity of 0.1 wt% L92/0.1 wt% P123 was slightly increased compared to 0.1 wt% L92 mono system and other binary systems. These nano-sized binary systems may have potential as alternative drug delivery systems with simple preparation method and overcome the drawbacks of mono systems such as low stability and loading capacity.