• KSBB Journal
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• v.32 no.3
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• pp.206-211
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• 2017

The physical method used to prevent a landslide has the risk of environmental pollution. Calcite forming bacteria (CFB) have been received increasing attention as a novel and environmental friendly strategy for the soil improvement. In this study, we selected 11 CFB strains with high calcite production. We also examined survivability and calcite productivity of the strains under various stress conditions to select strains with high resistance to various stresses. Two strains was selected by environment stress. Sphingobacterium sp. KJ-32 and Viridibacillus arenosi B-25 precipitate calcite more than other strains at pH 5 and $15^{\circ}C$ respectively. Bio-consolidated soil cakes were made using various calcium salts (calcium chloride, calcium acetate, calcium lactate, calcium gluconate) with mixed culture of 2 strains. Among them, the calcite made using calcium chloride was the largest. These observations demonstrate that this bio-consolidation technology has the potential for eco-friendly prevention of landslide and soil improvement.

• The Korean Journal of Physiology
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• v.26 no.2
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• pp.123-128
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• 1992

The present study was undertaken to examine if endogenous nitric oxide is partly responsible for the high calcium induced vasorelaxation in vitro. Isolated porcine coronary arterial rings were suspended in the tissue chamber and their changes in isometric tension were recorded. KCI little affected the vascular tension in the calcium free media, but subsequent addition of cumulative doses of $CaCl_3$ from 1 to 40 mM caused a contraction followed by complete relaxation. The maximum tension was noted at the calcium concentration in the media of 5 mM, and then the tension progressively declined at 10-40 mM. The relaxation was slightly attenuated in the endothelium-denuded preparation. The relaxation was converted into a contraction by the addition of methylene blue. The relaxation response was not affected in the presence of indomethacin, but was significantly attenuated by $N^w-nitro-L-arginine$ methyl ester pretreatment. These results suggest that the calcium induced vasorelaxation is in part attributable to the release of endogenous nitric oxide.

• Advances in concrete construction
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• v.11 no.3
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• pp.183-192
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• 2021

Due to economic and environmental benefits, increasing the substitution ratio of ordinary cement by industry by-products like fly ash (FA) is one of the best approaches to reduce the impact of the concrete industry on the environment. However, as the substitution rate of FA increases, it will have an adverse impact on the performance of cement-based materials, so the actual substitution rate of FA is limited to around 10-30%. Therefore, in order to increase the early-age strength of high replacement (30-70%) low-calcium ultrafine FA blended cement paste, sodium sulfate and calcium sulfate dihydrate were used to improve the reactivity of FA. The results show that sodium sulfate has a significant enhancement effect on the strength of the composite pastes in the early and late ages, while calcium sulfate dihydrate has only a slight effect in the late ages. The addition of sodium sulfate in the cement-FA blended system can enhance the gain rate of non-evaporation water, and can decrease the Ca(OH)2 content. In addition, when the sulfate chemical activators are added, the ettringite content increases, and the surface of the FA is dissolved and hydrated.

• Journal of the Korean Society of Food Science and Nutrition
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• v.16 no.1
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• pp.42-47
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• 1987

The present studies were undertaken to prepare calcium acetate from sea-mussel shell and then, to investigate the calcium absorption ratio for calcium acetate by using young albino rate male. Purities such as chloride, nitrate, nitrate, sulfate, phosphate and heavy metal passed to test as reagent grade and calcium acetate assay was 99.0%. No significant differences in the body weight gain between calcium acetate group, calcium gluconate group and calcium carbonate group were not recognized. Diet consumptions of calcium acetate group was almost similar with calcium gluconate group and calcium carbonate group. It was found that absorption rate of calcium acetate was $57.68{\pm}0.83%,\;58.08{\pm}0.94%$ and was $2.0{\sim}3.0%$ high than calcium gluconate and calcium carbonate group.

• Journal of Nutrition and Health
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• v.30 no.6
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• pp.605-613
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• 1997

This study was to investigate interaction between dietary protein and Ca levels in Ca metabolism and renal function in osteporosis rats. Five week-old female rats were fed a low Ca diet for 4 weeks after ovariectomy operation to establish rat models of osteoporosis. The ovariectomized osteoporosis rats were divided into six groups and were fed experimental diets which contained two levels of protein, normal (20%) and high(40%) , and three levels of Ca, low (0.06%), normal (0.47%) and high(0.94%) for 4 weeks , respectively. The ovaricetmized rat model of osteoporosis showed a remarkable decrease in serum Ca concentration, fresh weight and breaking force of femur, Ca and P contents of femur, and apparent absorption and retention of Ca. The supplementations of Ca and P contents of femur, and apparent absorption and retention of Ca. The supplementations of Ca at the dietary levels of normal and high levels significantly enhanced Ca bioavailability shown in the above experimental rat models of osteoporosis, regardless of dietary protein levels ; whereas the rats which were fed the low Ca diet demonstrated rather a decrease in its bioavailability. Irrespectively of the dietary Ca levels, the rats which were fed high protein diet exhibited an increase in kidney weight, urinary Ca, volume and hydroxyproline, and glomerular filtration ratio(GFR). The results show that dietary protein and calcium levels affect the renal function and Ca metabolism independently, while the interaction between protein and calcium have not been shown.

• Journal of Plant Biology
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• v.32 no.4
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• pp.343-350
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• 1989

Calcium promoted ethylene production from mungbean hypocotyl segments incubated in the presence of either auxin or cytokinin (kinetin). Time course studies indicated that the calcium effect on ethylene production had a longer latent period (about 6 h) in combination with kinetin than with auxin. Studies on the effects of agents that are known to interfere with either action or transport (uptake) of calcium on ethylene biosynthesis indicated different patterns between auxin- and kinetin-treated tissues. Auxin-induced ethylene production was inhibited by the calmodulin inhibitor, trifluoperazine (TFP), and this inhibition was overcome by high concentrations of calcium applied, but TFP had no significant effect on kinetin-induced ethylene production regardless of calcium in the medium. The calcium channel blocker, verapamil, inhibited auxin-induced, but had little effect on kinetin-induced, ethylene producton. In vivo activity of "ethylene forming enzyme (EFE)" was found to be substantially promoted by calcium treatment. The enzyme activity was further increased by kinetin when segments were simultaneously treated with calcium, but auxin did not have such an effect.an effect.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.6
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• pp.631-636
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• 2019

Fish bone-based calcium products are currently receiving much attention among high value-added industries involving calcium. Industrial processing of fish products yields unused fish parts including bones, which could be used as marine health foods to enhance the economic and environmental benefits of fish production. The ultimate goal of this study is to develop the high value-added fisheries products fortified with fish bones supplementing calcium. We here explored the physical and chemical softening methods of the fish bones to enhance texture of the fish products with a high degree of calcium absorption rates. The eluted calcium from the fish bone was quantified with the inductively coupled plasma optical emission spectrometry (ICP-OES). The characteristics of the softened fish bones were determined by the laser diffraction particle size analysis, texture profile analysis, and volatile organic compounds (VOCs) analysis. As the result, the optimized softening method of fish bone was established when Theragra chalcogramma bone was treated twice with the pressurized high temperature (110-120℃ and 1.0-1.5 kg/cm²). The produced softened fish bone turned out to be suitable for the food additives with low particle sizes, low hardness values, and negligible VOCs responsible for the unpleasant flavors.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.30 no.4
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• pp.143-149
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• 2020

Calcium phosphates recognized as important bio-materials have been successfully synthesized by simple precipitation using waste abalone shells, which are rich mineral sources of calcium. Calcium hydroxide (Ca(OH)₂) originated from abalone shells was used as calcium source (precursor) for the preparation. Synthesis of calcium phosphates was performed by reacting calcium hydroxide with phosphoric acid (H₃PO₄) in aqueous solution. The initial precursor Ca/P ratios were adjusted to 1.50, 1.59 and 1.67, and the effect of the composition and the heat treatment on the synthesized powders and sintered bodies was investigated. The phases of the sintered ceramics prepared at 1150℃ were hydroxyapatite (HAp), β-tricalcium phosphate (β-TCP), and biphasic phosphate (HAp with β-TCP)), which were determined by the initial precursor Ca/P ratios. The results demonstrate the possibility for the synthesis of high value-added calcium phosphates from economical starting materials with low cost and high availability.

• Journal of Nutrition and Health
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• v.39 no.8
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• pp.733-741
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• 2006

The study was conducted to investigate the effects of dietary calcium and soy isoflavone on body fat and lipid metabolism in high fat-induced obesity. Four week old female C57/BL6J mice, known as a good model of diet-induced obesity, were fed low Ca and high fat diet for 6 weeks. After induced obesity, mice were divided into six groups according to diets varying calcium contents (0.1 or 1.5%) and genistein contents (0 or 500 or 1,000 ppm). Body weight, fat pad (perirenal fat and parameterial fat), adipocyte size, serum total lipid and total cholesterol were significantly decreased by both high Ca intake and genistein supplementation. However, the effect of genistein supplementation showed in low Ca-fed groups. Serum LDL-cholesterol and TG were significantly decreased by high Ca intake and genistein supplementation, respectively. In liver, lipogenic enzymes (fatty acid synthase and malic enzyme) activity and TG were significantly decreased by both high Ca intake and genistein supplementation. This inhibitory effect of genistein on lipogenic enzymes showed in low Ca-fed groups. But liver total cholesterol and total lipid were significantly decreased by high Ca intake and genistein supplementation, respectively. Fecal excretion of total lipid, total cholesterol and TG were significantly increased by high Ca intake, not by genistein supplementation. In conclusion, high calcium intake and genistein supplement may be beneficial for suppression of obesity through direct anti-adipogenesis by decreasing fat weight and size and indirect anti-lipo-genesis by inhibiting lipogenic enzymes activity and improving lipid profile.

• Korean Journal of Rural Living Science
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• v.6 no.1
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• pp.31-39
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• 1995

This study was performed to observe how soy protein and calcium in rats fed unsaturated fat-enriched diet affect the total lipid and cholesterol contents of blood and tissues male Sprague-Dawley rats weighing approximately 220g were fed four purified diets which contained 18% (w/w) corn oil, 1% (w/w) cholesterol, two sources of protein : casein or isolated soy protein (ISP) and two levels of dietary calcium : 0.1% or 1.0%, first for four weeks (Expt. 1) and second for eight weeks (Expt. 2). The contents of total lipid, cholesterol and triglyceride in blood, liver, heart and feces were determined. After four weeks feeding, the serum lipid and cholesterol concentration was not significantly different among the groups. After eight weeks feeding, these concentrations were significantly lower in ISP-High calcium group. The serum lipid concentration was influenced by dietary protein sources and calcium levels. These results indicated that the hypolipidemic effects of soy protein and high calcium intake were partly due to decrease in lipid absorption and these effects were not detected at 4 weeks feeding but 8 weeks feeding.