• Environmental Analysis Health and Toxicology
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• v.24 no.2
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• pp.127-136
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• 2009

We have investigated the genotoxicity of 3 chemicals, aluminum oxide, calcium oxide, sodium tetraborate using mammalian erythrocyte with micronucleus induction. It was performed using 9 week male ICR mice. At 24 hours after treatment with 3 chemicals with oral route, mice were sacrificed and bone marrow cells were prepared for smear slides. As a result of counting the micronucleated polychromatic erythrocyte (MNPCE) of 2,000 polychromatic erythrocytes (PCE), all treatment groups did not show statistically significant increase than negative control group. And there was no clinical sign related with injection of the 3 chemicals. It was concluded that the 3 chemicals did not induce micronucleus in the bone marrow cells of ICR mice, and these results indicate that the 3 chemicals have no mutagenic potential under the condition in each studies.

• Journal of the Korean Ceramic Society
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• v.28 no.9
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• pp.739-749
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• 1991

Calcium hydroxide fine powders were synthesized by hydration of calcium oxide, and the shapes of powders obtained were examined for each synthethic condition. When distilled water was used as a solvent, irregular and agglomerated submicron powders were obtained, and it was impossible to control of the shapes. In methanol-added solutions, hexagonal plate-like particles were obtained, but addition of ethanol had no effect. However on the occasion that substituted ethylene glycol for ethanol of 5 vol%, hexagonal plate-like powders were obtained. The shapes of powders synthesized in acetic acid and salicylic acid solutions were hexagonal platelike, and were spherical and very fine in citric acid and oxalic acid solutions, respectively. But in some solutions, calcium salts were precipitated by the reaction between calcium and acid added. And the size of powders were very fine using ultrasonic vibration instead of mechanical agitation.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.2
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• pp.153-159
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• 2004

This study was focused on evaluating physical properties and SO$_{x}$ removal capability of porous lime filters prepared by a foaming and a gelcasting method. Porosities of lime filters ranged from 55% to 85%, and their mean pore sizes were about 95 ${\mu}{\textrm}{m}$. It was observed that porous lime filters had the continuous pore structure that most pores were inter-connected by many windows. Before SO$_{x}$ removal reaction a surface of porous lime filters was made up of calcium oxide, but after reaction calcium sulfate became a main component. The SO$_{x}$ removal efficiency and the conversion ratio of calcium oxide to calcium sulfate increased according to reaction temperature and porosity. At 100$0^{\circ}C$, SO$_{x}$ removal efficiency of filters was always over 98% regardless of the porosity. In case of the filter with the porosity of 85%, the conversion ratios of calcium oxide increased according to the reaction temperature, and they were in the range 30% to 60%. to 60%.

• Journal of the Korean Electrochemical Society
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• v.5 no.2
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• pp.43-46
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• 2002

Commercial titanium rod was anodized in three types of electrolytes such as 0.06 mol/L $\beta-glycerophosphate+0.3mol/L$ calcium acetate, 0.06mol/L $\beta-glycerophosphate+0.3mol/L$ sodium acetate and 0.06 mol/L $\beta-glycerophosphate+5mol/L$ calcium phosphate. The titanium oxide layer $(TiO_2)$ was characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and electron spectroscopy chemical analysis (ESCA). Numerous micropores were observed on the titanium oxide layer by SEM. The diameter of micropores increased with the increase of electrolytic voltage. The titanium oxide layer was composed of anatase structure. The phosphorous element was detected at 130 eV binding energy, but calcium was not found in the oxide layer because of lower contents. After anodizing the oxide layer was etched in the 30g/L NaOH solution at $80^{\circ}C$ for 1hr. The surroundings of micropores were much more smoothed and rounded than before alkaline etching.

• Journal of the Korean GEO-environmental Society
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• v.11 no.11
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• pp.63-75
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• 2010

There are several remediation technologies for heavy metal contaminated soils but increasing cost limits the application of the technology if the contaminated area is large. Therefore, stabilization, which blocks the release of heavy metals or makes slow the release, is one of the applicable technology for the heavy metal contaminated soil. Current study is an applicability test for a smelter area with various stabilizer such as magnetite, hematite, zeolite-A, zeolite-X, zeolite-Y, zinc oxide, calcium oxide, carbon trioxide, manganese oxide, manganese dioxide, fish bone, sodium phosphate. The soil contaminated with arsenic, lead, copper, nickel, and zinc could not be stabilized only one stabilizer which is known to have stability for certain metal. Many of the stabilizer works for a few metal but not all of the heavy metal. In several cases, stabilizers increase the release of the other metals while they stabilize some metals. In general, the stabilizing efficiency was increased with time. For Ni, Pb, calcium oxide, carbon trioxide, manganese oxide had good stabilizing effect in water extractable portion. For Cu, manganese oxide, zeolite showed good results especially in the exchangeable portion of the sequential extraction. For As, magnetite had good ability but most of the metal oxide which showed good result for other heavy metals increased with the release of As. Current study suggest that multiple stabilizers are needed for the contaminated soil and dose of the stabilizer and stabilizing time should be carefully considered for the soil contaminated with various metals.

• Restorative Dentistry and Endodontics
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• v.6 no.1
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• pp.17-25
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• 1980

The purpose of this study was to evaluate the pulpal response against calcium hydroxide and zinc oxide containing various concentration of formocresol (0.1, 0.5, 1, 5, 10, 20 and 30%). The experiment was performed on dog's teeth (75 teeth from 5 dogs: Table 1.) and the teeth were routinly treated in laboratory procedures. Followings are the results obtained through microscopical examination. 1. In zinc oxide group, intlammatory reaction was severe in low concentrated formocresol and the (higher the concentration of formocresol the milder the inflammatory reaction was more evident. 2. In zinc oxide group, inflammatory change was milder at 3 weeks than 1 week, and proliferation of young connective tissue was seen at 3 weeks. 3. In calcium hydroxide group, inflammatory change in relation to the concentration of formocresol was not noticeable. 4. In calcium hydroxide group, repair process with decreased inflammatory reaction and fibrosis, and dentin bridge like layer was found at 3 weeks.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.6
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• pp.357-362
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• 2003

Carbon monoxide (CO) is low molecular weight oxide gas that is endogenously produced under physiological conditions and interacts with another gas, nitric oxide (NO), to act as a gastrointestinal messenger. The aim of this study was to determine the effects of exogenous CO on L-type calcium channel currents of human jejunal circular smooth muscle cells. Cells were voltage clamped with 10 mM barium ($Ba^{2+}$) as the charge carrier, and CO was directly applied into the bath to avoid perfusion induced effects on the recorded currents. 0.2% CO was increased barium current ($I_{Ba}$) by $15{\pm}2$% ($mean{\pm}S.E.$, p<0.01, n=11) in the cells. To determine if the effects of CO on barium current were mediated through the cGMP pathway, cells were pretreated with 1-H-[1,2,4]oxadiazolo[4,3,-a]quinoxalin-1-one (ODQ, $10{mu}M$), a soluble guanylyl cyclase inhibitor, and exogenous CO (0.2%) had no effect on barium currents in the presence of ODQ ($2{\pm}1$% increase, n=6, p>0.05). CO mediates inhibitory neurotransmission through the nitric oxide pathway. Therefore, to determine if the effects of CO on L-calcium channels were also mediated through NO, cells were incubated with $N^G-nitro-L-arginine$ (L-NNA, 1 mM), a nitric oxide synthase inhibitor. After L-NNA pretreatment, 0.2 % CO did not increase barium current ($4{\pm}2$% increase, n=6, p>0.05). NO donor, SNAP ($20{\mu}M$) increased barium current by $13{\pm}2$% (n=6, p<0.05) in human jejunal smooth muscle cells. These data suggest that CO activates L-type calcium channels through NO/cGMP dependant mechanism.

• The Korean Journal of Physiology and Pharmacology
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• v.23 no.5
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• pp.345-356
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• 2019

Docosahexaenoic acid (DHA), an omega-3-fatty acid, modulates multiple cellular functions. In this study, we addressed the effects of DHA on human umbilical vein endothelial cell calcium transient and endothelial nitric oxide synthase (eNOS) phosphorylation under control and adenosine triphosphate (ATP, $100{\mu}M$) stimulated conditions. Cells were treated for 48 h with DHA concentrations from 3 to $50{\mu}M$. Calcium transient was measured using the fluorescent dye Fura-2-AM and eNOS phosphorylation was addressed by western blot. DHA dose-dependently reduced the ATP stimulated $Ca^{2+}$-transient. This effect was preserved in the presence of BAPTA (10 and $20{\mu}M$) which chelated the intracellular calcium, but eliminated after withdrawal of extracellular calcium, application of 2-aminoethoxy-diphenylborane ($75{\mu}M$) to inhibit store-operated calcium channel or thapsigargin ($2{\mu}M$) to delete calcium store. In addition, DHA ($12{\mu}M$) increased ser1177/thr495 phosphorylation of eNOS under baseline conditions but had no significant effect on this ratio under conditions of ATP stimulation. In conclusion, DHA dose-dependently inhibited the ATP-induced calcium transient, probably via store-operated calcium channels. Furthermore, DHA changed eNOS phosphorylation suggesting activation of the enzyme. Hence, DHA may shift the regulation of eNOS away from a $Ca^{2+}$ activated mode to a preferentially controlled phosphorylation mode.

• Restorative Dentistry and Endodontics
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• v.16 no.1
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• pp.25-40
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• 1991

Four root canal sealers, Apatite Root Sealer I and II composed mainly of hydroxyapatite/tricalciumphosphate, Sealapex containing calcium hydroxide, and Roth Sealer composed of zinc oxide - eugenol were compared on the culture of L929 fibroblasts. MIT (Methyl Thiazole Tetrazolium Bromide) colorimetric technique was used to measure the mitochondrial dehydrogenase activity. Results were as follows: 1. Hydroxyapatite/tricalcium phosphate mixed sealers were significantly less toxic compared with calcium hydroxide and zinc oxide - eugenol type sealers. High pH of the calcium hydroxide sealer and release of eugenol component from the zinc oxide - eugenol type sealer were presumed to be the cause of the toxicity of these two sealers. In no cases, there were more cytoblastic effects in hydroxyapatite/tricalcium phosphate mixed sealers compared to the control groups. 2. In all experimental groups, toxicity was decreased as dilutions were increased. However in zinc oxide-eugenol type sealer the cell activity was weakened for all dilution groups. 3. Regarding the effect of setting time, Apatite I and Sealapex were less toxic as the setting progressed. Apatite II kept constant regardless of the different time ellapsed after setting but Roth sealer revealed significantly higher toxicity for all experimental groups. 4. Comparing two different culture periods of 24 hours and 72 hours, Apatite I showed higher cell activities in longer period(72 hours) while Apatite II did not. Sealapex and Roth sealer, however, showed significantly lower cell activities in longer period.

• Geotechnical Engineering
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• v.2 no.3
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• pp.5-14
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• 1986

The results of stabilization process in silty.clays and sand-silts, which were, respectively, treated with Calcium hydroxide of the Calcium series and Aluminium Sulphate of the Aluminium series are follows. 1) In the former case used calcium hydrate and calcium cabonate for silty-clays, calcium aluminnium cabonate oxide hydrate and calcium carbonate for sandy-silts were produced 2) In the latter case used Aluminium Sulphate, by X-ray diffraction test, it was found that Aluminium Oxide was produced both in silty-clays and sandy-silts 3) As the results of stabilization process, in the former case, unconfined compression strength was increased greatly but in the latter case it was little increased.