• Asian-Australasian Journal of Animal Sciences
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• v.20 no.8
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• pp.1266-1271
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• 2007

This study examined effects of calcium supplemented milk on bone loss in ovariectomized rats. Twenty four Sprague-Dawley female rats, 7 weeks-old, were divided into 4 groups, ovariectomized and fed diets containing: 1) control, no Ca supplemented milk, 2) ovx 1, Ca carbonate supplemented milk, 3) ovx 2, ionized Ca supplemented milk, and 4) ovx 3, nano Ca supplemented milk. All rats were fed 1 ml of milk containing 20 mg supplemented Ca. After 18 wk feeding, body weight gain and food efficiency ratio were significantly different between ovx 1 and ovx 3. Serum concentration of calcium and phosphorus were not different among groups. However, there was a significant difference in calcium content of dry femoral weight in ovx 3 compared with the control and ovx 2. In addition, femoral bone mineral density ($g/cm^2$) was significantly greater in ovx 3 than in other groups (p<0.05). The ovx 3 group showed the highest stiffness (N/mm), maximum energy (N) in femur and trabecular bone area (%). The present study indicated that nano Ca supplementation in milk may be an effective way to enhance bone calcium metabolism for ovariectomized rats.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.10
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• pp.1363-1370
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• 2006

This study was designed to evaluate the effect of Agaricus blazei $\beta-glucan$ and egg shell calcium complex on bone metabolism in ovariectomized (OVX) rats. Forty Sprague-Dewley female rats, 10 weeks of age $(248{\pm}1.7g)$, were divided into 4 groups and fed on the experimental diets for 6 weeks: sham operated control treated with normal diet containing 0.5% calcium (Sham-C), OVX-control treated with normal diet containing 0.5% calcium (OVX-C), $OVX-\beta-glucan$ group treated with $\beta-glucan$ diet containing 0.5% calcium (OVX-G), and $OVX-\beta-glucan$ egg shell calcium complex treated with $OVX-\beta-glucan$ egg shell calcium complex containing 0.5% calcium (OVX-GE). Bone weight of femur was higher in the OVX-GE group than in the other OVX groups. Bone mineral density of femur was significantly different (p<0.05) among the experimental groups and showed the highest level in the OVX-GE group. Calcium absorption rate and retention were higher in the $\beta-glucan$ supplement groups than in the other groups (p<0.05). Alkaline phosphatase activities and osteocalcin levels of serum showed lower in the $\beta-glucan$ supplement groups than in the OVX-C group. Deoxypyridinoline crosslink values of urine, indicator of bone absorption, showed the lowest in the OVX-GE group. The $\beta-glucan$ supplemented groups had a lower bone resorption ratio than in the OVX-C group. We concluded that bioavailability of calcium is higher in $\beta-glucan$ supplement groups compared to those in OVX rats. From the above results, these findings suggest the possibility of using $\beta-glucan$ egg shell calcium complex as a functional food material related to bone metabolism, even though there is no significant difference between the groups of $\beta-glucan$ and $\beta-glucan-egg$ shell calcium complex supplementation.

• Journal of the Korean Ceramic Society
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• v.28 no.11
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• pp.885-891
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• 1991

Calcium hydroxyapatite have been synthesized by a direct precipitation reaction between 0.05 M calcium hydroxide suspension and 0.3 M orthophosphoric acid solution. 0.01 M calcium hydroxide solution was added during the reaction in order to increase the total Ca/P mol ration and reaction pH of the solution. The stoichiometric hydroxyapatite was synthesized over 1.75 as total Ca/P mol ratio, but the calcium-deficient hydroxyapatite was prepared under 1.725 as total Ca/P mol ratio. The nonstoichiometry of the precipitates were interpreted in terms of the pH change during the reaction.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.4
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• pp.1-9
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• 2020

This study conducted to understand effects of CA (CaAl₂O₄) and CA₂ (CaAl₄O₇) ratio on chloride binding ability and compressive strength and pore structure of cement mortar incorporating mixture of CA and CA₂. The Portland cement based specimens were mixed with the clinkers CA and CA₂, and these calcium aluminate clinker mixture were replaced 0, 5, 10% by weight of cement. After all the test specimens were cured for 28 days under water curing, they were immersed in the distilled water and NaCl solution. As a result, 28 days compressive strength of all specimens was similar, and As the replacement ratio of calcium aluminate clinker in the specimen increased, Friedel's salt production tended to increase. However, it was dependent on the amount of Al₂O₃ in the level of 5% replacement and CA ratio in the level of 10% replacement. Through equilibrium isotherm result, it was also indicated that as replacement ratio of calcium aluminate clinker in cement matrix increased, chloride binding capacity was improved, and chloride penetration was suppressed. In this study, the specimen replaced with 10% of the calcium aluminate clinker mixture (CA 39%, CA₂ 60%) was remarkable to control chloride attack. We figured out necessity to understand optimal CA/CA₂ ratio to effectively apply CA₂ as a sustainable building material by improving the chloride binding ability in Portland cement based system.

• The Korean Journal of Zoology
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• v.34 no.4
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• pp.460-468
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• 1991

계배 limb bud간충직 연골원성 세포로부터 연골원세포로의 분화과정에서 Ca2+의 역할을 추구해 보기 위하여 Hamburger-Hamilton stage 23/24의 계배 limb bud간충직세포들을 미세배양법으로 배양하면서, Ca2+, calcium ionophore인 A23187, calcium channel blocker인 D600을 각각 농도 및 처리기간을 변화시켜 처리하면서 연골화의 정도를 검정하여, 연골세포 분화에 미치는 Ca2+의 작용양상을 분석하였다. 그 결과 Ca2+은 3 mM의 농도로 배양초기에 처리하였을 때 가장 효과적으로 연골화를 촉진하였으며, A23187(0.05 $\mu$ M) 처리는 세포내로 Ca2+유입을 증가시켜 연골화를 촉진시킨 반면, D6OO(30 $\mu$ M이하) 처리는 세포내로 Ca2+ 유입을 차단시킴으로서 연골화를 억제하는 것으로 나타났다. 이러한 결과에 따른 세포내로의 칼슘 유입 변화는 45Ca로 확인하였다. 그러므로 Ca2+에 의한 간충직세포의 연골세포로의 분화촉진 작용은 Ca2+이 연골화의 응집시기에 세포간의 접촉을 유도할 뿐만 아니라 배양 초기에 Ca2+이 세포 내로 들어감으로써 수반되는 일련의 기작에 의한 것임을 알았다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.3
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• pp.677-684
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• 1999

This study has dealt the effect of Ca regulating hormones and dietary Ca levels on Ca metabolism. Animals(BALB/c mice) were divided into three dietary groups(high and medium Ca and Ca free) and hormones including parathyroid hormone(PTH), calcitonin(CT), cholecalciferol(Vit D) were i.p. injected. After feeding experimental diets for five weeks, mice were anaethetized and sacrificed by heart puncture. We found that femur growth of mouse was slightly increased by high dietary Ca without showing statistical significance comparing to low dietary Ca group. The combination of PTH and CT showed the same effect when dietary Ca was high. At the same time, total mineral retention in bone was most affected by dietary Ca. In general, high Ca diet elevated Ca level in the serum. When dietary Ca was low, PTH stimulated Ca release from the bone into the serum, which was shown to be inhibited by CT treatment. Comparing to the control, PTH, Vit D and CT together tended to inhibit serum Ca level at high and medium dietary Ca. PTH and Vit D inhibited Ca reserve in the liver at all dietary levels of Ca. Both PTH and Vit D stimulated bone Ca retention when dietary Ca was low, but this effect was reversed when dietary Ca was high. When PTH, Vit D and CT were administered together, bone Ca level was greatly enhanced at low dietary Ca than at high dietary Ca, which suggests that these hormonal cooperation is needed for proper bone density maintenance especially when dietary minerals are not sufficient.

• Journal of Nutrition and Health
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• v.28 no.4
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• pp.309-320
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• 1995

The purpose of this research was to investigate the effect of calcium levels(50, 100 and 200% of requirement) on metabolism of Ca, Na and K in Young and adult female rats for 3 weeks. There was no significant difference in feed intake, body weight gain and feed efficiency ratio among the groups of different Ca intake level. Serum Na level of high-Ca group was significantly lower than that of low-Ca or normal-Ca group in Young rats. There was no significant difference in liver Ca and K contents among the groups of different Ca intake levels. But, Na content in liver was decreased by the increase of dietary Ca intake. Ca content in kidney of high-Ca group in young rats and normal-Ca group in adult rats were significantly higher than those of other groups. Na content in kidney of low-Ca group was lower than those of normal-Ca and high-Ca groups. Urinary excretions of Na and K and fecal excretion of Ca were increased by the increase of dietary Ca intake. But, fecal excretions of Na and K were not affected by dietary Ca intake. According to this study, it was found that the high Ca consumption promotes excretions of fecal Ca and urinary Na and K in rats. The study verifies the need for more study on the interrelationship among Ca, Na and K metabolism and bood pressure.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.2
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• pp.412-419
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• 2004

To investigate the utilization of calcium lactates (CaL) as coagulants for tofu manufacture, the quality characteristics and shelf-life of tofu made by CaL-P (black snail powder) and CaL-A (black snail ash) were investigated and compared to calcium chloride (CC), magnesium chloride (MC), calcium sulfate (CS ) and standard calcium lactate (CaL-S). And also, total microbe and turbidity of the tofu were determined during storage at 1$0^{\circ}C$. Coagulation ability of CaL-A was the highest, and the ability of CaL-P was higher than that of CaL-S. Yield of CaL-A tofu was similar to those of CS and CC tofu, while the yield of CaL-P tofu was 50% compared to that of CC. L＊ value of CaL-P tofu was lower, but a＊ and b＊ values were higher than those of other tofus. The hardness of tofu showed in the order of CaL-S>CS>CC>CaL-P>MC>CaL-A, while the cohesiveness showed in the order of MC>CaL-S>CC>CS>CaL-P>CaL-A. Calcium contents were 57 mg% in MC tofu, 174 mg% in CS tofu, 116 mg% in CaL-S tofu, 95 mg% in CaL-A tofu and 172 mg% in CaL-P tofu. From the results of microscopic observations, the lower hardness showed the more soft and the smaller particle. The particle of CaL-A tofu was small and uniformity but the size of CaL-P and CC tofu showed coarse. Sensory quality of CaL-P and -A tofu were better than the other tofu evaluated by texture, springiness, flavor and overall taste. The shelf-life estimated by total microbe was 4∼6 days in CC, MC, CS, CaL-S and CaL-A tofu, but 8 days in CaL-P tofu at 1$0^{\circ}C$. From the above results, the CaL-P and -A may believe to use as coagulant for tofu manufacture due to its softened taste and enhanced shelf-life, and higher calcium content which has higher absorbability in human body.

• The Korean Journal of Physiology
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• v.10 no.1
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• pp.1-5
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• 1976

The trypanocidal drug suramin, an impermeant polyanion, has been shown to be a powerful inhibitor of the calcium uptake and calcium-stimulated ATPase activity of sarcoplasmic reticulum (Fortes et al., 1974). In view of this finding, an attempt was made to investigate the effect of suramin on $Ca^{++}$ transport in resealed red cells and on $Ca^{++}$-activated ATPase in red blood cell membrane fragments (RBCMF). The results obtained are summarized as follows. 1. $Ca^{++}$ outflux from the resealed RBC was inhibited by suramin and the inhibitory action of suramin is proportional to the concentration of drug added inside the RBC preparation. When suramin is added both inside and outside the RBC preparation simultaneously, the magnitude of the inhibitory effect was more pronounced, suggesting that suramin inhibits both active $Ca^{++}-^{45}Ca$ exchange diffusion across the RBC membrane. 2. Suramin inhibits the $Ca^{++}$-activated ATPase of the RBCMF and the effect of inhibition by the drug was also concentration dependent. From the above results, it may be concluded that suramin inhibits $Ca^{++}$ transport across RBC membrane by inhibiting $Ca^{++}$-activated ATPase activity which has been known to be linked with active $Ca^{++}$ transport.

• 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.