• BMB Reports
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• v.29 no.3
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• pp.200-204
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• 1996

Nerve growth factor (NGF) is literally known to promote neural differentiation and survival in several peripheral and central neurons. Thus, it is Widely believed that NGF may serve as a therapeutic agent for many types of neuronal diseases. One of the mechanisms suggested to explain the protective role of NGF is that the trophic factor can prevent the increase of intracellular calcium ions which might be responsible for neural death. To examine whether or not the calcium hypothesis works even under pathological conditions, we applied NGF to cultures deprived of glucose. Surprisingly, what was observed here is that NGF rather promoted cell death under a glucose-deprived condition. What we call the NGF paradox phenomenon occurred in a calcium concentration-dependent manner, indirectly suggesting that NGF might increase intracellular calcium ions in cells deprived of glucose. This suggestion is further supported by the fact that nifedipine, a well-known L-type calcium channel blocker, could block the cell death potentiated by NGF. Here it is still premature to propose the complete mechanism underlying the NGF paradox phenomenon. However, this study certainly indicates that NGF as a therapeutic agent for neuronal diseases should be carefully considered before use.

• Journal of Food Hygiene and Safety
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• v.13 no.3
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• pp.258-267
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• 1998

The acetaminophen (AP AP), an antipyretic and analgesic agent, induces the hepatotoxicity by increasing influx of calcium and destabilizing the cellular membrane which can be caused by N-acetyl-p-benzoquinoneimine generated by cytochrome P-450 (CYF-450) when it is overdosed. Diltiazem (DIL), a calcium channel blocking agent, has been known to suppress the CYF-450 activities. To study the effect of DIL in APAP treated rats, the serum biotransformational enzyme analyses and the liver histopathologic examination were conducted on the rats which had been administered DIL at 3, 6, 9 and 12 hours after the 3,000 mg/kg of APAP administration. Following a single dose of DIL administered 12 hours after AP AP administration, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, malondialdehyde and calcium contents of liver and microsome were significantly reduced. Glutathione S-transferase (GST) activity was significantly increased. Histopathologic studies showed that DIL had prevented the development of centrilobular necrosis induced by AP AP in liver tissue. Our results suggested that diltiazem could inhibit the formation of free radical and the influx of calcium and could increase GST activity. Therefore, diltiazem can be administered at the time of 12 hours after overdosed AP AP to diminish the liver damage.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.6
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• pp.132-139
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• 2017

A huge amount of de-icing agent is sprayed during winter to promote traffic safety in cold regions, and the quantity of de-icing agent sprayed has increased each year. The main ingredients in commonly used de-icing agents are chlorides, such as calcium chloride($CaCl_2$) and sodium chloride(NaCl). While calcium chloride is mostly used in Korea and sodium chloride is usually used in the U.S. and Japan, all de-icing agents include chloride ions. The chlorides included in sprayed calcium chloride-based de-icing agents have severe adverse effects, including the corrosion of reinforcing steels through salt damage by infiltrating into road structures, reduced structural performance of pavement or damage to bridge structures, and surface scaling, in combination with freezing damage in winter, as well as water pollution. In addition, the deterioration of paved concrete road surface that occurs after the use of calcium chloride-based de-icing agent accelerates the development of visual problems with traffic structures. Therefore, the present study was performed to prepare an environment-friendly liquid de-icing agent through a reaction between waste organic acids and calcium-based by-products, which are industrial by-products, and to analyze the properties of the de-icing agent in order to evaluate its applicability to road facilities.

• Economic and Environmental Geology
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• v.56 no.5
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• pp.619-628
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• 2023

In this study, we investigated the feasibility of calcium sulfate fertilizer as a stabilizing agent for As and Hg contaminated farmland soil and its stabilization characteristics in 3 different physical forms (particulate, powder, and solution) through a pot experiment including 34 days of lettuce growth. As and Hg contents of the lettuce grown in the stabilized soils were decreased by at least 70%. However the lettuce yield of the soil stabilized with the solution agent was decreased by 46% due to the overabundance of the nutrients from the solution agent. Thus, if a solution-type agent is planned for agricultural farmland soil stabilization, additional tests for optimal dosage are needed to preserve vegetation growth. In Hg fractionation, a lower concentration of elemental fractions and a higher concentration of residual/sulfide fractions were identified in the soils stabilized with the solution, powder, and pariculate agents in descending order while there were no significant changes in As fractionation. Overall results suggest that calcium sulfate fertilizer can be used as a stabilizing agent, and a solution-type agent could be used when the operation of heavy machinery for the soil stabilization process is impossible.

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.4
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• pp.231-233
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• 2002

The potential of calcium peroxide to act as an agent for waterblooming control was In-vestigated by examining the growth inhibition of Microcystis aerusinosa. Due to the chemical nature of calcium peroxide, it can remove dissolved phosphate by forming an Insoluble precipitate, generating radicals, coagulant, and oxygen as byproducts as it dissolves in water. The growth of M. aerusinosa was severely inhibited and the chlorophyll-n concentration was drastically decreased in the presence of calcium peroxide. With 200 ppm of calcium peroxide dosage, a chlorophyll-a concentration of 1,700 mg/m$^3$ was lowered to below 10% of its initial concentration after 4 days. One possible explanation for this growth Inhibition is the removal of the available phosphate by calcium peroxide.

• Journal of Bio-Environment Control
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• v.16 no.1
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• pp.21-26
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• 2007

This study was carried out to investigate the effects of tree-spray of calcium formate compound extracted from oyster shell with several active agents on the calcium concentration, fruit skin shape and quality of 'Fuji' apple. The tree-spray of calcium formate compound extracted from oyster shell (Os-CaF, $52.4\;mg{\cdot}kg^{-1}$) appeared to have more effectiveness on the calcium translocation into leaves, fruit skin and flesh than control. Addition of adjuvants to Os-CaF increased calcium concentration of 'Fuji' apple when sprayed three times before harvest. Among the active agents examined, the treatment ascorbic acid and poly-vinyl alcohol (PVA) in leaves, Ag-colloidal and PVA in fruit skin, ascorbic acid, Ag-colloidal, and PVA in fruit flesh exhibited highest effectiveness. Fruit qualities (fruit weight, firmness, soluble solids, acidity and Hunter value) were not affect by Os-CaF on different concentrations and solutions of active agents.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.3
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• pp.198-203
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• 2003

Heat-induced surimi gels were prepared using various concentration of ATC as a additives and calcium agent. Regardless of various concentration of ATC, there were no difference the moisture $(80.4-81.2\%)\;and\;crude\;ash\;(1.4-1.\5%)$ contents. The pH of heat-induced surimi gels were decreased 7.16 to 7.04 depend on increasing ATC concentration. The whiteness, breaking force and gel strength of $0.09\%$surimi gel were improved significantly difference (p<0.05). Sensory evaluation on texture and whiteness were also similar to determination by color and texture meters. In mineral content of heat-induced surimi gel calcium content was increased 26 to 54 mg/100g depend on increasing ATC concentration, while phosphorus content was not change. The optimal concentration of ATC for preparation of high quality heat-induced surimi gel was $0.09\%$. The shelf-life of heat-induced surimi gel did not extend by addition of $0.09\%$ ATC.

• Clean Technology
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• v.24 no.4
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• pp.315-322
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• 2018

Industrial use of waste oyster shells is limited because of requiring excessive energy for converting natural oyster shells in the form of calcium carbonate ($CaCO_3$) into calcium oxide (CaO) for this purpose. This study aimed to develop energy-saving process for producing solidifying agent using waste oyster shells for backfill materials. It was suggested that oyster shells were converted to calcium sulfates which were mixed with sodium hydroxide solution and red clay, forming solid specimen. The optimal concentrations of sulfuric acid for sulfation of oyster shell and sodium hydroxide to generate calcium hydroxide ($Ca(OH)_2$), were determined. Unconfined compressive strength of solid specimen increased with increasing the content of solidifying agent while it increased also with increasing ratio of natural oyster shells to coal ash. The result clearly demonstrates that solidifying agent consisting of sulfuric acid-treated oyster shell, coal ash, and sodium hydroxide solution, can be effectively utilized for preparing backfill materials using natural oyster shell and coal ash. Sulfuric acid-treated oyster shell-based solidifying agent has not been previously developed and will contribute to broaden industrial application of waste oyster shells.

• Proceedings of the Materials Research Society of Korea Conference
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• 2006.05a
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• pp.8.2-8.2
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• 2006

• Journal of Adhesion and Interface
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• v.9 no.2
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• pp.24-31
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• 2008

In this work, calcium hydroxide and magnesium carbonate as metal ionic crosslinking agents were used to introduce ionic crosslinking points to the ethylene vinylacetate (EVA) emulsions for the enhancement of water resistance and mechanical properties of emulsion films. The properties of EVA emulsion film were investigated in crosslinking density, thermal features, surface energy, and mechanical properties, such as tensile strength, elongation at break and tear strength. With the increasing content of metal ionic crosslinking agent, the crosslinking density of the EVA emulsion film increases, resulting into the improvement of water resistance. The surface energy and mechanical properties of the EVA emulsion film, however, showed somewhat different behaviors. The highest surface energy, tensile strength, and tear strength were observed when 0.4% for calcium hydroxide and 0.5% for magnesium carbonate was added respectively, because the EVA emulsion containing carboxylic acid forms strong carboxylate-metal bond of ionically-crosslinked system. Therefore, it can be concluded that metal ionic crosslinking agents, such as magnesium carbonate and calcium hydroxide are considered to improve water resistance and mechanical properties of the EVA emulsion.