• Journal of Life Science
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• v.30 no.2
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• pp.191-201
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• 2020

As society develops rapidly, environmental pollution is becoming a greater risk factor threatening human health. One of the major causes of air pollution that affects human health is particulate matter (PM), which contains a heterogeneous mixture of different particle sizes and chemical compositions. PM is classified by size into general PM (PM₁₀; diameter below 10 ㎛) and fine PM (PM_2.5; diameter below 2.5 ㎛). PM_2.5 can pass through the respiratory tract into the circulatory system and thence throughout the body. PM_2.5 is known to stimulate oxidative stress and inflammatory responses to cells, promoting diseases such as asthma, chronic respiratory disease, cardiovascular disease, diabetes mellitus, and immunological disorders. Although detailed molecular mechanisms for how PM stimulates disease progression still need to be elucidated, together with national efforts to reduce PM production, significant research has been conducted that demonstrates the harmfulness of PM in disease progression through in vitro and in vivo experiments. This review focuses on the harmfulness of PM in disease progression; we also introduce a biological verification method for determining the hazards of PM.

• Korean Journal of Food Science and Technology
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• v.36 no.6
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• pp.959-967
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• 2004

To screen probiotic lactic acid bacteria with potent adhesive property on human colonic mucosa, colonic mucin-binding assay was introduced. This colonic mucin-binding assay actually measures the binding activity of surface lectin-like protein (SLP) on colonic mucin, and the optimal conditions were examined. The optimal pH for colonic mucin coating on plate wells was 4.8, and ${\times}24,000$ diluted solution of commercially available horseradish peroxidase (HRP) conjugated streptoavidin yielded good results, for rapid screening, $5.0\;{\mu}g/mL$ of biotinylated SLP from lactic acid bacteria was optimal, and optimal scintillation time of 3,3',5,5'-tetramethyl benzidine (TMB) was 10 min. These conditions were useful for both rapid selection and quantitative analysis of lactic acid bacteria that have high adhesion property to human intestinal tract. Among 50 strains of lactic acid bacteria, including 32 type culture strains and 18 isolated strains from infant feces, Lactobacillus species FSB-1 isolated from kimchi showed the highest binding activity to colonic mucin. From taxonomical viewpoints based on morphological study, physico-biochemical study, partial 16S rDNA seguencing, and phylogenetic analysis, L. species FSB-1 was identified as Lactobacillus brevis.

• Korean Journal of Food Science and Technology
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• v.16 no.4
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• pp.418-422
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• 1984

In order to determine the removal efficiency of pesticide residues in fruits and vegetables by washing processes, samples of lettuce, young Chinese radish, Chinese cabbage, green red pepper, strawberry and grape were artificially contaminated with malathion and washed according to the household practices. After three times washings with water, the remaining ratios of malathion residues in grape, green red pepper, strawberry, young Chinese radish, lettuce and Chinese cabbage were 9.7%, 25.2%, 28.0%, 29.7%, 38.9% and 57.5%, respectively. After washing with detergent solution followed by two times rinsing with water, the remaining ratios of malathion residues in the same food samples were 1.6%, 8.3%, 15.8%, 24.8%, 27.2% and 45.9%, respectively. The removal efficiency of malathion by detergent washing was significantly higher than the water washings only. The removal ratio of malathion residues was the highest in the first washing and the ratio fell greatly in the following washings. The removal efficiency was not quite different in the temperature range of $5-35^{\circ}C$ of the washing solution, but the efficiency at $100^{\circ}C$ was 2-3 times higher than other temperature ranges.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.2 no.3
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• pp.189-199
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• 2004

A bridge transported servo manipulator (BTSM) system for the advanced spent fuel conditioning process (ACP) has been developed to overcome the limitation of access, which is a drawback of mechanical master-slave manipulators (MSM) for the equipment maintenance. The servo manipulator is composed of a slave manipulator attached to the telescoping tubesets equipped with the overhead bridge installed at a hot cell and a master manipulator installed at an out-of-hot cell. Each manipulator has 7 degrees-of-freedom (DOF): a body rotation, an upper-arm tilt, a lower-arm tilt, a lower-arm rotation, a wrist pan & tilt, and a grasp motion. A wire-driven mechanism for a lower-arm rotation, a wrist pan and tilt, and a grasp motion of the manipulator has been adopted to increase the handling capacity compared to the manipulator weight and decrease the friction. The main disadvantage of the wire-driven mechanism is that if one link is in motion, other links can be affected. In this paper, the transmission characteristics among the wire-driven links have been formulated to overcome this drawback. The unexpected behaviors are confirmed by analyses of transmission characteristics as well as experiments. Also, the experimental results show that the unexpected behaviors are greatly decreased by the proposed compensation equations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.2
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• pp.493-499
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• 2008

This study was performed to estimate the water quality parameters on corrosion such as pH, turbidity, Fe released concentration, corrosion rate by using batch reactor for corrosion control of phosphate corrosion inhibitor in carbon steel pipes. The pH, conductivity, alkalinity, and Ca hardness showed a slight change for dosing the phosphate corrosion inhibitor with carbon steel pipe in batch reactor. The turbidity was about ten times lower with 5 mg $P_2O_5/L$ of the corrosion inhibitor than that without. The Fe released concentration and corrosion rate was decreased by about 12.2, 24 times with 5 mg $P_2O_5/L$ of the corrosion inhibitor than that without. In conclusion, the optimum concentration of the phosphate corrosion inhibitor was found to be 5 mg $P_2O_5/L$. The effect of the corrosion inhibitor was significant for the carbon steel plate samples tested in this study. The corrosion inhibitor can be an effective cure for corrosion and red water problem preventing the service pipe from further corrosion.

• Journal of the Korean Wood Science and Technology
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• v.35 no.6
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• pp.100-107
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• 2007

People have spent lots of time inside building about 90% of these day. Industry has been developed rapidly after I960. Construction materials had changed from natural materials to chemical materials and confidentiality of building has been more higher than before by policy of saving energy. These have caused sick-building syndrome (SBS) for us. So people want environmental construction materials for their house. We designed a environmental loess (yellow soil) finishing material which was composed of loess, water, water-soluble resin, hardener and filler. The purposes of this study were that making an environmental loess finishing material with optimum ratio, evaluating the usability of loess finishing material for wall. Furthermore it was suitable for wall to evaluate mechanical properties that are impact test, cracking test, abrasion test and de-bonding test, environmental properties that were emission of VOCs, formaldehyde and far infrared radiation.

• Korean Journal of Microbiology
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• v.51 no.2
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• pp.156-168
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• 2015

The objective of this study is to investigate the anti-Helicobacter pylori and anti-cancer activities of the live cells (LC), cell-free culture supernatants (CFCS), and bacteriocin solution (BS) obtained from Lactobacillus acidophilus BK13 and Lactobacillus paracasei BK57 strains. After incubation for 30 h in MRS broth, the concentration of lactic acid produced by L. paracasei BK57 ($155.9{\pm}10.2mM$) was higher than in MRS broth using L. acidophilus BK13 ($126.8{\pm}7.9mM$). Maximum bacteriocin activity (128 AU/ml) of BK13 strain was observed after 30 h of cultivation at $37^{\circ}C$, however its magnitude was significantly lower than that of BK57 strain (256 AU/ml). The LC of L. acidophilus BK13 and L. paracasei BK57 were able to inhibit the growth of H. pylori ATCC 43504 at different incubation times, depending on the initial inoculum of the LAB. These CFCS and BS obtained from BK13 and BK57 strains dramatically inhibited the growth, adhesive ability, and enzymatic activity of H. pylori. Meanwhile, the anti-cancer effect of the lactic acid from L. acidophilus BK13 and L. paracasei BK57 strains on AGS cells had significant differences with the control group. Therefore, these antagonistic substances-producing strains are potentially useful as new potential antimicrobial agents for the management and prevention of H. pylori infections.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.1
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• pp.103-111
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• 2020

Pulling-type cutting devices, which use a diamond wire saw, have been used generally for cutting concrete structures. In this study, a pushing-type cutting device with a collection cover was developed by overcoming the disadvantages of pulling-type devices. In this device, dry or liquid methods can be selected to cool frictional heat. Operation and leakage tests of the dust generated during the dismantling of a concrete structure were carried out, confirming the suitable operation of the fabricated cutting device; the leakage rate was approximately 1.7%. For a conservative evaluation, the internal dose of workers was estimated in dismantling the core center part of biological shield concrete with a specific activity of 99.5 Bq·g^-1. The committed effective dose per worker was 0.25 mSv. The developed cutting device contributed to reducing radioactive concrete waste and minimizing worker exposure due to its easy installation. Therefore, it can be utilized as a cutting apparatus for dismantling not only reinforced concrete structures but also radioactive biological shield concrete in nuclear power plant decommissioning efforts.

• Korean Journal of Clinical Laboratory Science
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• v.47 no.3
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• pp.117-124
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• 2015

Mesenchymal stem cells (MSCs) are an attractive tool in tissue engineering as they have the required potential to treat injured articular cartilage. UV-exposed DTOPV (S-triazine bridged p-phenylene vinylene) is a biocompatible and fluorescent polymer with a hydrophilic surface. Previous studies have demonstrated that the surface wettability and hydrophilicity play critical roles in regulating cell adhesion and proliferation. The objective of this study was to improve the potential of in vitro MSC differentiation into Chondrocytes using DTOPV. MSCs were cultured on two different substrates: (1) tissue culture polystyrene (TCPS) as a reference and (2) UV-exposed and patterned DTOPV films. Chondrogenesis of MSCs was induced for two weeks on TCPS and DTOPV in the presence of an induction medium containing transforming growth factor (TGF)-${\beta}3$. Interestingly, the MSCs on TCPS adhered and spread, while those on DTOPV tended to form aggregates within several days. The cells cultured on DTOPV for two weeks had a round morphology, with stronger Safranine O staining of the extracellular matrix than that of the cells cultured on TCPS. Also, Type II collagen gene was significantly expressed in cells induced on DTOPV. These results indicate that chondrogenic differentiation of MSCs proceeds more rapidly on DTOPV than on TCPS. Therefore, in cartilage tissue engineering, DTOPV could be used to induce effective chondrogenic differentiation of MSCs.

• Applied Chemistry for Engineering
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• v.10 no.2
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• pp.293-298
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• 1999

Reaction mechanism was elucidated and reaction condition were optimized for the catalytic reaction synthesizing 2-methyl-4-methoxy-diphenylamine (MMDPA) which is an intermediate of Fluoran heat-sensitive dyestuff. Reactants consisted of 2-methyl-4-methoxyaniline (MMA), 3-methyl-4-nitroanisole (MNA), and cyclohexanone, and 5 wt % Pd/C was used as a catalyst. Experiments were run in an open slurry reactor equipped with reflux condenser, and products were analyzed by means of GC/MS and NMR. MMDPA yield of 90 mole % could be obtained after reaction time of 8~10 hours under the optimal reaction conditions comprising the reaction mass composition of MMA : MNA : cyclohexanone = 1 : 2 : 150 based on MMA input of 0.01 gmoles in xylene solvent, reaction temperature of $160^{\circ}C$, and catalyst amount of 0.5 g. It was found that the rate-determining step of overall reaction was dehydrogenation of the intermediate product obtained from condensation of MMA and cyclohexanone. Overall reaction rate and MMDPA yield were enhanced owing to hydrogen transfer reaction by introducing MNA together with MMA in the reaction mass. Excess cyclohexanone in the reaction mass played an important role of promoting the condensation of MMA and cyclohexanone.