• Journal of the Korean Ceramic Society
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• v.14 no.4
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• pp.230-235
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• 1977

In this paper the conditions of surface crystallization of glass were studied. The basic glass which is apt to crystallize, with $SiO_2$ 72.50, $Al_2O_3$ 5, 00, $Na_2O$ 8.00 $K_2O$ 3.50, CaO 5.00, MgO 3.00, $B_2O_3$ 3.00 Wt% is chosen. The strain point and softening point of this glass is 4$25^{\circ}C$ and 778$^{\circ}C$ each, and between the two temperatures we could get grystal on its surface by immersion in salt baths during some controlled hours. The kind of crystal on the surface of glass was confirmed by X-ray diffraction analysis and the change of the thickness of crystalline layers depending on temperature and time, was surveyed by using optical microscope. The results are as follows; 1. The chloride group is more suitable than sulfate group for the treating salt. 2. In the condition with 50 LiCl.50NaCl at 62$0^{\circ}C$ for 2 hrs and with 50 LiCL.20-30 NaCl.30-20 $CaCl_2$ at 72$0^{\circ}C$ for 15-20 min. we could get the best crystalline layers. 3. The crystal was silica-O and petalite with a little tridymite and nepheline. 4. The thickness of crystalline layers increased with increasement of temperature and time.

• The Korean Journal of Physiology and Pharmacology
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• v.15 no.5
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• pp.279-283
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• 2011

Quercetin (3,3',4',5,7-pentahydroxyflavone) is an attractive therapeutic flavonoid for cancer treatment because of its beneficial properties including apoptotic, antioxidant, and antiproliferative effects on cancer cells. However, the exact mechanism of action of quercetin on ion channel modulation is poorly understood in bladder cancer 253J cells. In this study, we demonstrated that large conductance $Ca^{2+}$-activated $K^+$ ($BK_{Ca}$) or MaxiK channels were functionally expressed in 253J cells, and quercetin increased $BK_{Ca}$ current in a concentration dependent and reversible manner using a whole cell patch configuration. The half maximal activation concentration ($IC_{50}$) of quercetin was $45.5{\pm}7.2{\mu}m$. The quercetin-evoked $BK_{Ca}$ current was inhibited by tetraethylammonium (TEA; 5 mM) a non-specific $BK_{Ca}$ blocker and iberiotoxin (IBX; 100 nM) a $BK_{Ca}$-specific blocker. Quercetin-induced membrane hyperpolarization was measured by fluorescence-activated cell sorting (FACS) with voltage sensitive dye, bis (1,3-dibutylbarbituric acid) trimethine oxonol ($DiBAC_4$2(3); 100 nM). Quercetin-evoked hyperpolarization was prevented by TEA. Quercetin produced an antiproliferative effect ($30.3{\pm}13.5%$) which was recovered to $53.3{\pm}10.5%$ and $72.9{\pm}3.7%$ by TEA and IBX, respectively. Taken together our results indicate that activation of $BK_{Ca}$ channels may be considered an important target related to the action of quercetin on human bladder cancer cells.

• Journal of the Korean Wood Science and Technology
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• v.27 no.4
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• pp.72-79
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• 1999

The ability of several wood rotting fungi for decolorization of two anthracene derivatives, Carminic acid (CA) and Remazol brilliant blue R (RBBR), and hardwood KP bleaching liquor (BL) as well as laccase activities in these fungi were studied. The enzyme activity appeared exclusively in fungi destaining RBBR and CA, but in the case of BL, such relationship was not observed. The laccase enzyme was released into the decolorization media and its inducible (but not constitutive) forms shown destaining activity. The purified inducible forms of Kuehneromyces mutabilis and Pleurotus ostreatus laccase destained CA. Thus the possible differentiation between specificity of particular LAC forms was confirmed. In addition the nitrogen starvation induced both laccase and CA destaining activities, but the increase was higher for decolorization of CA than LAC activity. Probably LAC would be only partly responsible for decolorization of this dye. This results suggested that purified LACs decolorize CA, however its destaining activities were considerably lower than the activities on syringaldazine.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.3
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• pp.37-45
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• 2021

Purpose : This study aimed to present normative data and cut-off points for older Korean adults completing the Montreal Cognitive Assessment - Korean (MoCA-K), which is used as a screening test for mild cognitive impairment in Korea. Methods : A total of 195 healthy adults ≥60 years were recruited. All participants completed the MoCA-K and the Korean - Mini-Mental State Examination (MMSE-K) to assess their cognitive function. Participants were divided into six groups based on their age: 60-64 years, 65~69 years, 70~74 years, 75~79 years, 80~84 years, and 85~89 years. Results : The results revealed that MoCA-K score decreased significantly with age (mean score ± standard deviation [SD]; 27.63±2.80 in subjects aged 60~64 years; 27.00±2.39 in subjects aged 65~69 years; 24.94±2.96 in subjects aged 70~74 years; 24.74±3.37 in subjects aged 75~79 years; 22.59±4.72 in subjects aged 80~84 years; and 18.83±5.38 in subjects aged 85~89 years; p<.001). Additionally, MoCA-K score also increased significantly with educational level (mean score±standard deviation [SD]; 19.95±4.78 in no formal education group; 24.95±2.22 in elementary school graduated group; 26.35±2.72 in middle school graduated group; 28.32±1.36 in high school graduated group; and 28.50±1.51 in more than college graduated group; p<.001). The optimal cut-off points were 24/25 for 60~69 years old group, 21/22 for 70~79 years old group, 17/18 for 80~84 years old group, and 13/14 for 85~89 years old group. The optimal cut-off points were 15/16 for individuals who were illiterate, 22/23 for individuals with 6 years of education, 22/24 for individuals with 9 years of education, and 26/27 for individuals with 12 or more years of education. Conclusions : This study presents normative data and cut-off points for the MoCA-K in older Korean adults. This data will facilitate more accurate detection and follow-up of the risk of mild cognitive impairment in this population, taking into consideration age and education. Future studies are required that should focus on the cut-off score on the level of education according to age.

• Journal of the Korean Ceramic Society
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• v.34 no.10
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• pp.1083-1091
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• 1997

As one of the chemical powder fabrication methods, the powder preparation method by using oxalate has the following advantages; (1) easy to control the chemical stoichiometry, (2) easy to fabricate homogeneous and fine particles, and (3) easy to be thermaly decomposed at low temperature. In the present study, the initial morphology and size distribution of the powder were controlled and the homogeniaty was improved. By carefully controlling the pH with NH4OH, the Bi(Pb)-Sr-Ca-Cu-O superconducting powders were prepared and investigated for their properties. The microstructures and the superconducting properties of the pelletized samples were investigated. Also, the microstructures and electrical properties of the samples prepared by tape casting method were investigated. The fabricated powders were spherical with less than 400 nm, but most of them were agglomerated to be 1~3 ${\mu}{\textrm}{m}$ in size. The critical temperature of the pelletized sample annealed at 84$0^{\circ}C$ for 72 hours in air was 110K. And the critical currents of annealed samples in air prepared by tape casting process for 24 hours and 72 hours were 0.6 A (Jc=600A/$\textrm{cm}^2$) and 1.9A (Jc=1, 900A/$\textrm{cm}^2$) respectively.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.3
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• pp.179-191
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• 2013

This study was conducted to comparatively assess quantitative indicating factor for biomineralization characterizing $CO_2$ mineralization on three type of minerals (i.e., $CaCl_2$, $MgCl_2$, $CaCl_2-MgCl_2$) in an aqueous solution amended with Bacillus pasteurii or indigenous microorganisms for a S landfill cover soil. For given three types of minerals, $NH_4{^+}$ (urease activity) was released at the highest of 88 mg/L for $MgCl_2$, then 85 mg/L for $CaCl_2$, and the lowest of 42 mg/L for $CaCl_2-MgCl_2$. $CO_2$ gas in the head space was completely removed after 12, 12, and 24 hr for $CaCl_2$, $MgCl_2$ and $CaCl_2-MgCl_2$, respectively. $Ca^{2+}$ concentration in $CaCl_2$ solution was the quickest and the greatest decreased 92% for 12 hr whereas that in $CaCl_2-MgCl_2$ solution was lower at 85% for 36 hr. $Mg^{2+}$ concentration in $MgCl_2$ was more efficiently decreased at 46% for 48 hr than that of $CaCl_2-MgCl_2$ solution of 38.5% for 72 hr. Regardless of types of minerals or their concentration, pH was changed from 5.5 to 9 by biomineralization being progressed. Microbial activity ($OD_{600}$) was also changed from 0 to 0.6. SEM images indicated that spheroidal and trapezoid shape crystal were formed, which were identified as of $CaCO_3$ (Calcite) and $MgCO_3$ (Magnesite) by X-ray diffraction. In the long run, $NH_4{^+}$ (urease activity), $CO_2$ gas, $OD_{600}$, pH, $Ca^{2+}$ and $Mg^{2+}$ would be suitable for reasonable indicating factor in order to assess the degree of biomineralization efficiency.

• Microbiology and Biotechnology Letters
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• v.7 no.3
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• pp.157-164
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• 1979

These experiments were performed to investigate the culture condition, characteristic of crude enzyme and the heat resistance of the acid protease by Aspergillus awamori U-3. The results obtained were as follows: 1. The optimum culture temperature and time on wheat bran medium and defatted rice bran medium were 3$0^{\circ}C$ and 72 hrs, respectively. The optimum amount of added water was 100~120 ％ on wheat bran medium and 100~130 ％ on de-fatted rice bran medium. 2. Of the these various ingredients, addition of KN $O_3$, glutamic acid and glucose on wheat bran medium and addition Of KN $O_3$, (N $H_4$)$_2$S $O_4$, glucose, lactose, K $H_2$P $O_4$ and MgC $l_2$ on defatted rice bran medium were very effective. On wheat bran medium, concentration of addition of glucose, KN $O_3$ and glutamic acid were 3.0~4.0％, 0.2~0.4 ％ and 1.0％, respectively. 3. The optimum pH for the enzyme action was 2.4 ％, the optimum temperature about 45$^{\circ}C$ and the stable pH range 2.0~5.0, The enzyme was stable below 5$0^{\circ}C$ and was inactivated rapidly above 5$0^{\circ}C$. 4. The addition of CaC $l_2$ and CaS $O_4$ as the heat resistance agents showed the slight resistance. 5. When the enzyme solution added with the heat resistance agents (CaC1$_{2}$ and CaS $O_2$) was heated for 10-30 minutes at 6$0^{\circ}C$, their remaining activities were decreased largely above 20 minutes and The heat resistance effects of CaC $l_2$ and CaS $O_4$ were not observed almost at 8$0^{\circ}C$.

• Molecular & Cellular Toxicology
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• v.4 no.3
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• pp.218-223
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• 2008

Oxidative stress is believed to contribute to the neuronal damage induced by cerebral ischemia/reperfusion injury. The present study was undertaken to evaluate the possible antioxidant neuroprotective effect of hydroxyfullerene (a radical absorbing cage molecule) against neuronal death in hippocampal CA1 neurons following transient global cerebral ischemia in the rat. Transient global cerebral ischemia was induced in male Wistar rats by four vessel- occlusion (4VO) for 10 min. Lipid peroxidation in brain tissues was determined by measuring the concentrations of thiobarbituric acid-reactive substances (TBARS). Furthermore, the apoptotic effects of ${H_2}{O_2}$ on PC12 cells were also investigated. Cell viabilities were measured using MTT [3-(4,5-dimethylthiazolyl-2)-2,-5-diphenyltetrazolium bromide] assays. Hydroxyfullerene, when administered to rats at 0.3-3 mg/kg i.p. at 0 and 90 minutes after 4-VO was found to significantly reduce CA1 neuron death by 72.4% on hippocampal CA1 neurons. Our findings suggest that hydroxyfullerene protects neurons from transient global cerebral injury in the rat hippocampus by reducing oxidative stress and lipid peroxidation levels, which contribute to apoptotic cell death.

• Journal of Conservation Science
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• v.21
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• pp.59-72
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• 2007

The relationship between soluble salts and microbial growth on stone surface was investigated. Samples from deteriorated surface layers of several stone monuments were collected, and the soluble salts in samples were chemically analysed. According to the results of chemical analyses, $Na_2SO_4$, $CaSO_4$ $2H_2O$, and NaCl and so on were added to isolation media. As a result of preliminary experiments, 15 bacteria were selected. They are all Gram positives and fourteen of them were rods. Every bacteria could grow not only in media without salts, but also in media with $CaCO_3$, $CaSO_4$ $2H_2O$, and $Ca(OH)_2$. Three bacteria, Bl6, B56, and B6l, secreted viscous substances in these $Ca^{2+}$ added media. $CaCl_2$ $2H_2O$ was the most hygroscopic among 11 soluble salts, but it seemed to interfere with bacterial growth. Ammonium ion was the inhibitor, too.

• Journal of the Korean earth science society
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• v.32 no.7
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• pp.707-718
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• 2011

We study the natural background and geochemical characteristics on geological groups of stream sediment in the Boseong-Hwasun area. We collected 186ea stream sediment samples along the primary channels and dried them naturally in laboratory. The contents of major, trace and rare earth elements were determined by XRF, ICP-AES and NAA analysis methods. In order to know the natural background and geochemical characteristics of geological groups, we classified the studied area into granitic gneiss (GGn) area and porphyroblastic gneiss (PGn) area. The contents range of major elements for GGn area is $SiO_2$ 45.5-73.09 wt.%, $Al_2O_3$ 12-20.76 wt.%, $Fe_2O_3$(T) 3.72-8.85 wt.%, $K_2O$ 2.38-4.2 wt.%, MgO 0.75-2.77 wt.%, $Na_2O$ 0.78-1.88 wt.%, CaO 0.27-2.1 wt.%, $TiO_2$ 0.56-1.72 wt.%, $P_2O_5$ 0.06-0.73 wt.% and MnO 0.03-0.95 wt.%, and for PGn area it is $SiO_2$ 43.74-70.71 wt.%, $Al_2O_3$ 11.54-25.05 wt.%, $Fe_2O_3$(T) 3.44-13.46 wt.%, $K_2O$ 2.08-3.86 wt.%, MgO 0.65-2.99 wt.%, $Na_2O$ 0.63-1.7 wt.%, CaO 0.35-2.07 wt.%, $TiO_2$ 0.68-4.17 wt.%, $P_2O_5$ 0.1-0.31 wt.% and MnO 0.07-0.33 wt.%. The contents range of hazard elements for GGn area is Cr 41.7-242 ppm, Co 7.6-25.1 ppm, Ni 12-61 ppm, Cu 10-47 ppm, Zn 48.5-412 ppm, Pb 17-215 ppm, and for PGn area, it is Cr 29.6-454 ppm, Co 5.9-53.7 ppm, Ni 8.7-287 ppm, Cu 6.4-134 ppm, Zn 43.6-370 ppm, Pb 15-37 ppm area. There is a good correlation between Cr and MgO and Co among $Al_2O_3$, $Fe_2O_3$(T), MgO and Ni among $Fe_2O_3$(T), CaO, MgO whereas Cu, Zn and Pb have a low correlation for major elements in GGn area. Generally Cr, Co, Ni, and Cu have a good correlation with major elements, but a low correlation with Zn and Pb in PGn area.