• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.15 no.2
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• pp.20-32
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• 2002

The aim of this study was to investigate the effect of Codonopsis lanceolatae on the melanogenesis of HM3KO human melanoma cells biologically. The cells were treated for 3 days and 5 days with Codonopsis lanceolatae at several concentrations. The effects on tyrosinase activity and melanin contents were examined. And DOPAchrome tautomerase(TRP-2) activity was also examined to search a pathway influencing this inhibitory effect. 1. It was examined mushroom tyrosinase activity was significantly inhibited by Codonopsis lanceolatae. 2. Treatment with Codonopsis lanceolatae did not affect cell viability at the highest concentration, 1 ㎎／ml, and suppressed melanin contents as a time and dose dependent manner. 3. It was investigated treatment with Codonopsis lanceolatae inhibited tyrosinase, a key enzyme forming melanin, activity in a dose-dependent manner. 4. Treatment with Codonopsis lanceolatae did not affect DOPAchrome tautomerase(TRP-2) activity. 5. There was not a morphological change by Codonopsis lanceolatae microscopically. These results suggest that Codonopsis lanceolatae is a candidate for an efficient whitening agent which supresses melanogenesis by a Raper-Mason pathway.

• Korean Journal of Materials Research
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• v.29 no.7
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• pp.425-431
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• 2019

Generally, ceramic tiles for building construction are manufactured by dry forming process using granular powders prepared by spray drying process after mixing and grinding of mineral raw materials. In recent years, as the demand for large ceramic tiles with natural texture has increased, the development of granule powders with high packing ratio and excellent flowability has become more important. In this study, ceramic tile granule powders are coated with hydrophobically treated silica nanoparticles. The effects of hydrophobic silica coating on the flowability of granule powders and the strength of the green body are investigated in detail. Silica nanoparticles are hydrophobically treated with GPTMS(3-glycidoxypropyl trimethoxy silane), which is an epoxy-based silane coupling agent. As the coating concentration increases, the angle of repose and the compressibility decrease. The tap density and flowability index increase after silica coating treatment. These results indicate that hydrophobic treatment can improve the flowability of the granular powder, and prevent cracking of green body at high pressure molding.

• Korean Journal of Metals and Materials
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• v.49 no.7
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• pp.530-534
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• 2011

To analyze the effect of the pore size of graphite in a pore-forming agent, graphite was added to porous ceramics of $Al_2O_3-SiO_2-ZrO_2$ systems. The graphite had 45~75, 100~125, 150~180, and 75~180${\mu}m$ dimensions. The properties of the ceramics, such as apparent porosity, density, dynamic elastic modulus, mechanical strength, and permeability, were investigated. The average pore size increased from 15.35${\mu}m$ to 22.32${\mu}m$ with the increase of the graphite size. The sample with the largest average pore size showed the highest mechanical strength and gas permeability. This was due to the sample with the largest pore size at the same porosity having fewer pores and larger distance between the pores than the sample with the smallest pore size, making cracks less likely to propagate. In addition, the large pore size reduced the repulsive power originating from the drag force between the gas and internal pore walls.

• Journal of Microbiology and Biotechnology
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• v.33 no.8
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• pp.1050-1056
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• 2023

Weizmannia coagulans (formerly Bacillus coagulans) is Gram-positive, and spore-forming bacteria causing food spoilage, especially in acidic canned food products. To control W. coagulans, we isolated a bacteriophage Youna2 from a sewage sludge sample. Morphological analysis revealed that phage Youna2 belongs to the Siphoviridae family with a non-contractile and flexible tail. Youna2 has 52,903 bp double-stranded DNA containing 61 open reading frames. There are no lysogeny-related genes, suggesting that Youna2 is a virulent phage. plyYouna2, a putative endolysin gene was identified in the genome of Youna2 and predicted to be composed of a N-acetylmuramoyl-L-alanine amidase domain (PF01520) at the N-terminus and unknown function DUF5776 domain (PF19087) at the C-terminus. While phage Youna2 has a narrow host range, infecting only certain strains of W. coagulans, PlyYouna2 exhibited a broad antimicrobial spectrum beyond the Bacillus genus. Interestingly, PlyYouna2 can lyse Gram-negative bacteria such as Escherichia coli, Yersinia enterocolitica, Pseudomonas putida and Cronobacter sakazakii without other additives to destabilize bacterial outer membrane. To the best of our knowledge, Youna2 is the first W. coagulans-infecting phage and we speculate its endolysin PlyYouna2 can provide the basis for the development of a novel biocontrol agent against various foodborne pathogens.

• Resources Recycling
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• v.15 no.2 s.70
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• pp.18-23
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• 2006

Foaming of slag is a thermodynamically unstable phenomenon and has significant effects in iron and steelmaking processes. For better recycling method of pulp sludge, the application as an defoaming agent during steelmaking process was adopted and tested. The forming machine has been modified in order to produce the briquettes, which are made of pulp sludge and slag with different weight ratio. Influencing factors on the foaming phenomena have been studied and tested for better understanding of foaming phenomena. Experiments were carried out with $CaO-FeO-SiO_2$ based slags with Ar gas injection and addition of coke particles. The slag basicity and (%FeO) contents adapted as major factors to treasure foaming tendency of the slag system. It was found that foam index (${\Sigma}$) gradually decreased as both the basicity and the (FeO) content increase. Four kinds of antifoaming agent such as aluminium dross, cokes, rice bran and pulp sludge with steelmaking slag have been tested in actual process. Aluminium dross was the most effective, and pulp sludge with steelmaking slag also showed the desired results.

• Applied Chemistry for Engineering
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• v.17 no.3
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• pp.243-249
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• 2006

Porous polymer gel electrolytes (PGEs) based on poly(vinylidenefluoride-co-hexafluoropropylene) (P(VdF-co-HFP)) as a polymer matrix and polyvinylpyrolidone (PVP) as a pore-forming agent were prepared and electrochemical properties were investigated for an electric double layer capacitor (EDLC) in order to increase a permeability of an electrolyte into the PGE. Propylene carbonate (PC) and ethylene carbonate (EC) as plasticizers, and tetraethylammonium tetrafluoroborate ($TEABF_4$) as a supporting salt for the PGE were used. EDLC unit cells were assembled with the PGE and electrode comprising BP-20 and MSP-20 as activated carbon powders, Super P as a conducting agent, and P(VdF-co-HFP)/PVP as a mixed binder. Ion conductivity of PGEs increased with an increased PVP content and was the best at 7 wt% PVP, whereas electrochemical characteristics such as AC-ESR of unit cell were better in 3 wt%. And electrochemical characteristics of the unit cell with PGE were the best at a 33 : 33 weight ratio of PC to EC. Specific capacitance of a mixed plasticizer system of PE and EC was higher than that of pure PC. Ion conductivity of PGEs with a film thickness of $20{\mu}m$ was higher, but electrochemical characteristics of unit cells were higher for a $50{\mu}m$ membrane thickness. Also, the unit cell has shown the highest capacitance of 31.41 F/g and more stable electrochemical performance when PGE and electrode were hot pressed. Consequently, the optimum composition ratio of PGE for EDLCs was 23 : 66 : 11 wt% such as P(VdF-co-HFP) : PVP = 20 : 3 wt% and PC : EC = 44 : 22 wt%. In this case, $3.17{\times}10^{-3}S/cm$ of ion conductivity was achieved at the $50{\mu}m$ thickness of PGE for EDLCs. And the electrochemical characteristics of unit cells were $2.69{\Omega}$ of DC-ESR, 28 F/g of specific capacitance, and 100% of coulombic efficiency.

• Journal of Life Science
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• v.23 no.2
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• pp.197-206
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• 2013

The present study investigated whether leukemia-maintaining cells reside in a differentiation-resistant fraction using a megakaryocytic differentiation model of K562 cells. Treatment with phorbol-12-myristate-13-acetate (PMA) significantly inhibited the colony-forming efficiency of the K562 cells. At a PMA concentration of 1 nM or higher, colony was not formed, but approximately 40% of K562 cells still survived in soft agar. Approximately 70% of colony-forming cells that were isolated following the removal of PMA after exposure to the agent were differentiated after treatment with 10 nM PMA for 3 days. The differentiation rate of the colony-forming cells was gradually increased and reached about 90% 6 weeks after colony isolation, which was comparable to the level of a PMA-treated K562 control. Meanwhile, imatinib-resistant variants from the K562 cells, including K562/R1, K562/R2, and K562/R3 cells, did not show any colony-forming activity, and most imatinib-resistant variants were CD44 positive. After 4 months of culture in drug-free medium, the surface level of CD44 was decreased in comparison with primary imatinib-resistant variants, and a few colonies were formed from K562/R3 cells. In these cells, Bcr-Abl, which was lost in the imatinib-resistant variants, was re-expressed, and the original phenotypes of the K562 cells were partially recovered. These results suggest that leukemia-maintaining cells might reside in a differentiation-resistant population. Differentiation therapy to eliminate leukemia-maintaining cells could be a successful treatment for leukemia if the leukemia-maintaining cells were exposed to a differentiation inducer for a long time and at a high dose.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.7
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• pp.824-831
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• 2009

In order to investigate the quality characteristics of powdered teas using Compositae species flower, the samples of Chrysanthemum indicum L. (CI), Chrysanthemum boreale Makino (CB), and Chrysanthemum zawadskii var. latilobum (Maxim.) Kitam (CZ) were extracted with hot water and concentrated, and then mixed with different forming agents of dextrin (D) and maltodextrin (MD). The mixing ratio of D and MD was ranged from 9:1 (DMD91) to 8:2 (DMD82) or D and MD only. The solubility of the powdered tea was higher in added dextrin. The highest total polyphenol and flavonoid content of the powdered tea were 6.75 and 3.24 mg/g at CBDMD91, respectively. Total antioxidant activities of C. indicum, C. boreale, and C. zawadskii powdered tea ranged at $2.51{\sim}2.63$, $4.37{\sim}4.50$, and $3.44{\sim}3.55\;mg$ AA eq/g, respectively. In sensory evaluation, the C. indicum and C. zawadskii powdered teas obtained higher sensory score of all evaluation items than C. boreale powdered tea. The optimal mixing ratio at 36% of D and 4% of MD in forming agent was selected to enhance the sensory characteristics and antioxidant activities of powdered tea.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.7 no.1
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• pp.24-30
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• 2004

Purpose: Acute diarrhea in young children is a major problem in pediatric hospitals worldwide. We evaluated the clinical efficacy of orally administered Lactobacillus acidophilus in the treatment of acute diarrhea in children. Methods: From September 2002 to July 2003 at National Police Hospital 41 children aged 3 months to 5 years with acute diarrhea were enrolled in this study. The patients were randomized to one of two groups to receive either $0.5{\times}10^8$ colony forming unit (CFU) of L. acidophilus or matching placebo on admission and every 8 hours during hospitalization. Results: The mean duration of diarrhea in all 41 children was decreased (p=0.001) in the L. acidophilus (40.5 hours) group compared to the placebo (56.6 hours) group. Stool frequency was also reduced (p=0.01) on the 3rd day in the L. acidophilus group. Rotavirus was identified in 58% of the patients. The decrease of duration of diarrhea was more significant in rotavirus-negative patients (p=0.002) compared to the rotavirus-positive patients (p=0.027). Conclusion: L. acidophilus shows to be an effective therapeutic agent in acute diarrhea in children. Further studies are needed to confirm the present findings.

• The Journal of Internal Korean Medicine
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• v.28 no.2
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• pp.304-320
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• 2007

Objective : To evaluate the effect of Astragalus Membranaceus Extrac (AME) on myelosuppression, activity and immune modulation in 5-fluorouracil (5-FU) treated mice. Method : We carried out complete blood count, histological analysis of bone marrow, and cell colony forming assay for hematopoietic progenitor to evaluate the effect of AME on myelosuppression and conducted swimming test, survival rate, nitric oxide (NO) assay, 51Cr release assay in natural killer cell, mRNA expression of $IL-1{\beta}$, IL-2, IL-4, IL-6, IL-10, $TNF-{\alpht}$, $IFN-{\gamma}$, $TGF-{\beta}$ and GM-CSF in spleen cells to evaluate the effect of AME on quality of life (QOL). Results : AME improved 5-FU induced myelosuppression and peripheral blood count was recovered effectively, had significant efficacy to protect against chemotherapy induced marrow-destruction and on hematopoiesis compared with the control group, improved increase survival rate and the swimming time, had a stimulatory effect on macrophage activation and NK cell activity, and up-regulated cytokine gene transcription (IL-2, IL-6, $IFN-{\gamma}$) in murine immunologic system. Conclusion : We can conclude that AM is an effective herbal agent for improvement of myelosuppression and QOL in 5-FU treated mice.