• Environmental Engineering Research
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• v.21 no.4
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• pp.341-349
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• 2016

To improve the utilization rate of construction waste as mine backfilling materials, this paper investigated the feasibility of using recycled powder as mine paste backfilling cementitious material, and studied the pozzolanic activity of recycled construction waste powder. In this study, alkali-calcium-sulfur served as the activation principle and an orthogonal test plan was performed to analyze the impact of the early strength agent, quick lime, and gypsum on the pozzolanic activity of the recycled powder. Our results indicated that in descending order, early strength agent > quick lime > gypsum affected the strength of the backfilling paste with recycled powder as a cementitious material during early phases. The strength during late phases was affected by, in descending order, quick lime > gypsum > early strength agent. Using setting time and early compressive strength as an analysis index as well as an extreme difference analysis, it was found that the optimal ratio of recycled powder cementitious material for mine paste backfilling was recycled powder:quick lime:gypsum:early strength agent at 78%:10%:8%:4%. X-ray diffraction analysis and scanning electron microscope were used to show that the hydration products of recycled powder cementitious material at the initial stages were mainly CH and ettringite. As hydration time increased, more and more recycled powder was activated. It mainly became calcium silicate hydrate, calcium aluminate hydrate, etc. In summary, recycled powder exhibited potential pozzolanic activities. When activated, it could replace cementitious materials to be used in mine backfill.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.2
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• pp.74-79
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• 2003

The functional properties such as a firming maintenance capacity for fermented vegetables, protein coagulation capacity antibacterial activity, calcium and peroxide absorption capacity of calcium powder of cuttle bone treated with acetic acid (ATC) were examined. In the Korean pickled cucumbers (20 days), the calcium content of ethanol insoluble solids was 5,264.9 mg/100 g and this value was higher than that of control (2,036.4 mg/100 g). Protein coagulation capacity of ATC was $0.9\%$ and its calcium absorption capacity was $49.3\%.$ The peroxide absorption capacity of ATC was shown $0-1.1\%$ range. Antibacterial activity was detected above $0.2\%.$ The ATC was effective in a firming maintenance of fermented vegetables (cucumber), coagulation capacities for soybean milk and antibacterial activity. The ATC was not effective in clarifying wastewater. Peroxide absorption capacity toward linoleic acid could not be checked by ATC, but its calcium absorption ratio was high compared to that of commercial calcium powder.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.593-596
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• 2003

The special amendment agent used in this study is mainly composed of inorganic metal salts such as sodium chloride, magnesium chloride, potassium chloride, calcium chloride, thus is friendly to the environment, and has a function of soil-cement-agent solidification. In this study, a series of laboratory and field experiments including unconfined compressive strength, permeability, pH test, constituent analysis, leaching test were carried out to analyse engineering and environmental characteristics of solidified sludge. The results of this research showed that the solidified sludge could be efficiently used in covering, filling, and planting materials.

• Journal of Korean Biological Nursing Science
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• v.18 no.3
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• pp.185-191
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• 2016

Purpose: The purpose of this study is to understand the effect of taking calcium/vitamin D supplements and performing Taekkyeon exercises on the frailty of the elderly targeting a vulnerable senior social group. Methods: A total of 124 people aged 65 and older consisting of 60 persons in the experimental group, and 64 persons in the control group participated in this study, and this study is a non-equivalent control group pre/post-test design quasi-experimental study. This study analyzed the homogeneity between the experimental group and the control group using a chi-square test and t-test while analyzing the difference in the degree of frailty and bone density with the practice of Taekkyeon and a calcium agent using t-test and GEE. Results: The study results showed that the frailty and bone density of the experimental group significantly improved. Conclusion: Through this study, it was confirmed that calcium/vitamin D intake and Taekkyeon exercises were an effective intervention which strengthened the elderly's physical condition.

• Journal of Adhesion and Interface
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• v.10 no.4
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• pp.182-190
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• 2009

In this work, effect of antistrip additives to reduce moisture damage of asphalt mixture were studied. Asphalt antistripping agents were prepared by condensation of formaldehyde with tetraethylene pentamine (TEPA), triethylenetetramine (TETA) and bis(hexamethylene)-triamine (BHMT), respectively. And also the metal type antistripping agent was prepatred by neutralization of stearic acid or palmitic acid with metal hydroxide. Mechanical characteristics of the asphalt mixture added antistripping agent were evaluated with Marshall stability, submerging residuals and coating rate. It was found that antistripping agent prepared in this study reduced moisture damages of asphalt mixtures. In particular, asphalt mixtures added BHMT and C/S (Calcium stearate hydroxide) antistripping agent showed highest submerging and coating rate. Because BHMT and C/S type antistripping agent was to improve bonding between asphalt and aggregate owing to increase of amine concentration and role of metal surfactant.

• Restorative Dentistry and Endodontics
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• v.10 no.1
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• pp.31-42
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• 1984

The toxic effect of adhesive resins on the dog's pulp tissue was studied with 70 teeth from 5 dogs. The experimental materials were Clearfil, a mixture of Clearfil with calcium hydroxide powder, Panavia-EX, and a mixture of Panavia-EX with calcium hydroxide powder. As a control group, calcium hydroxide powder was used. Each material was placed on the pulpotomized tissue surface. After 3 days, 1, 2,4, and 6 weeks, the teeth and apical tissue were processed routinly and stained with hematoxylin and eosin. Pathological tissue changes due to the toxicity of adhesive resins were observed by light microscope, and the pH of Panavia-EX and the Bonding agent of Clearfil were measured. Following were the results; 1. In the group of calcium hydroxide powder, slight inflammatory change was observed in the pulpotomized surface and adjacent pulp tissue on 3 day. 1 week case showed incomplete dentin bridge. The remaining pulp tissue was normalized according to the days elapsed. 2. In the group of Clearfil, early inflammatory change revealed in the superificial portion of the remaining pulp tissue on 3 day. The inflammation spreaded over the total pulp tissue and partial necrosis was observed in 1 week and 2 week cases. Total necrosis of pulp tissue and moderate inflammatory change at the apical tissue was noticed in 4 week and 6 week cases. 3. In the group of Panavia-EX, moderate inflammatory change appeared in the superficial pulp tissue on 3 day, and severe inflammatory change over all pulp tissue found in 1 week case. Pulp necrosis was obvious in 2 week case. 4 week and 6 week cases were totally necrotized up to the periapical tissue. 4. In the groups of mixtures with calcium hydroxide powder, the pulp tissue destruction was retarded, compared with the groups of Clearfil and Panavia-EX. 5. Panavia-EX was more destructive than Clearfil. 6. The acidity of freshly mixed Bonding agent of Cleafil was pH 4.0, and that of Panavia-EX was pH 2.0.

• Journal of Korea Foundry Society
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• v.25 no.5
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• pp.203-208
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• 2005

The main emphasis of this study is to optimize the process variables for manufacturing aluminum foam materials by direct foaming of remelted aluminum scraps. Aluminum foams were fabricated from two different raw materials, pure aluminum and used beverage cans. For both cases, $TiH_{2}$ was used as a foaming agent. Calcium was added as a thickener for the foaming of pure aluminum and no thickener was added for that of used beverage Cans because the pre-existing oxides of the used beverage cans are used as a thickener. Calcium and $TiH_{2}$ content varies from 0.5wt.% to 2.0wt.% and from 0.5wt.% to 1.5wt.%, respectively. The processing conditions, such as the effect of calcium on the melt viscosity, foaming temperature, and the optimum amount of the foaming agent with regard to the melt viscosity were discussed.

• Journal of Korean Society on Water Environment
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• v.32 no.5
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• pp.458-464
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• 2016

This study evaluated the dewatering efficiency of inorganic dehydrating agents that contain oyster shells. A filter press dehydrator was used for this study. The experiments were performed by the single injection of calcium-based chemicals, the single injection of oyster shells, and the mixed injection of oyster shells and calcium-based chemicals. The moisture content of the dewatered cake generated after dehydration confirmed that the best dewatering efficiency was found at the mixing ratios of CaCO₃ to sludge, oyster shell to sludge, and inorganic dehydrating agent to sludge of 3:1, 10:1, and 1.5:2.5:1, respectively. The moisture contents exhibited less than 58% when the injection mixing ratio of inorganic dehydrating agent to sludge was 1.5:2.5:1. From EPS, SEM, and EDX analysis, it was found that the calcium adsorbed on the sludge surface could reduce extracellular polymeric substances (EPSs) and enhanced the dewaterbility. Based on the above results, it is considered possible to apply inorganic dehydrating agents containing recycled oyster shells in sludge dewatering in order to reduce sludge.

• Biomolecules & Therapeutics
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• v.6 no.3
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• pp.247-255
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• 1998

Carbon tetrachloride (CCI$_4$) induces the hepatotoxicity due to the reactive free radicals generated by cytochrome P-450 (CYP-450) enzyme, which result in destabilization of cellular membrane. Diltiazem, a calcium channel blocking agent, has been known to suppress the CYP-450 enzyme activities. To study the effect of diltiazem in $CCl_4$-treated rats, we measured the activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and glutathione S-transferase (GST), contents of bilirubin, albumin, total protein, cholesterol, triglyceride, blood urea nitrogen, creatinine malondialdehyde and calcium. Also we conducted liver histopathologic examinations. Diltiazem, when administered 1 hour prior to CCI$_4$ treaeent, significantly reduced the activities of ALT and AST, the contents of microsomal malondialdehyde and calcium in liver and microsome as compared with those of $CCl_4$-treated rats. In addition, histopathologic examination showed that diltiazem prevented the development of centrilobular necrosis induced by CCI$_4$ in liver tissue. Our results suggested that diltiazem could inhibit the formation of free radicals and the influx of calcium. Therefore diltiazem may be applied to suppress the liver damage caused by $CCl_4$.

• Bulletin of the Korean Chemical Society
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• v.34 no.2
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• pp.549-552
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• 2013

An efficient and alternative synthesis of enantiomerically pure (+)-(S)-4-(4-((4-chlorophenyl)(pyrid-2-yl)methoxy]piperidin-1-yl)butanoic acid, bepotastine (1) is described. The key resolution of (R/S)-bepotastine l-menthyl ester (3) is achived via diastereomeric salt crystallization using N-benzyloxycarbonyl-L-aspartic acid (NCbzLAA) as the resolving agent to provide (S)-bepotastine l-menthyl ester (S)-3. Hydrolysis of (S)-bepotastine l-menthyl ester (S)-3 afforded the desired bepotastine (1) with good yields and enantiopurity (> 99%). Finally, bepotastine besilate (4) and bepotastine calcium (5) are achived by salt formation of bepotastine (1) with benzene sulfonic acid and calcium salt respectively. The reaction conditions were optimized to make suitable for commercial scale production.