• Journal of the Korean Ceramic Society
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• v.33 no.12
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• pp.1331-1338
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• 1996

In order to investigate the reaction in the system of fly ash-sulfuric acid-calcium hydroxide the hydrates were produced by the addition of Ca(OH)2 to fly ash activated with sulfuric acid at various temperatures. And then they were characterized by XRD. SEM and TG-DTA. It was found that in the reaction of fly ash with sulfuric acid fly ash was not decomposed but Al2O3 and SiO2 component in it were activated. The addition of calcium hydroxide into this system resulted in the formation of ettringite and calcium silicate hydrate (C-S-H) As the concentration of sulfuric acid and reaction temperature increased the amount of calcium hydroxide decreased fast. At this time gypsum produced by the reaction calcium hydroxide with sulfuric acid was consumed to form ettringite. Accordingly the formation of ettringite increased with calcium hydroxide and reaction time. And it showed faster than the formation of C-S-H.

• Journal of Periodontal and Implant Science
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• v.27 no.4
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• pp.785-804
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• 1997

It was well known that calcium sulfate was biocompatible, resorbed rapidly in the body, had potential as a good barrier membrane. Platelet-derived growth factor(PDGF) was one of polypeptide growth factor that had been reported as a biological mediator which regulates activities of wound healing process including the cell proliferation, migration and metabolism. The purpose of this study was to evaluate the effects of a combination of calcium sulfate and PDGF on periodontal ligament cells in vitro to use as a regeneration promoting agent of periodontal tissue. Human periodontal ligament cells were prepared from the premolar tooth extracted for the orthodontic treatment. Cells were cultured in ${\alpha}-MEM$ contained with 20% FBS, at the $37^{\circ}C$, 100% of humidity, 5% $Co_2$ incubator. Cells were inoculated and cultured into 96 well culture plate with $1{\times}10^4cells/well$ of ${\alpha}-MEM$ for 1 day. After discarding the medium, those cells were cultured in ${\alpha}-MEM$ contained with 10% FBS alone(control group), in calcium sulfate(calcium sulfate group), in calcium sulfate treated with 15ng/ml of PDGF-BB(calcium sulfate+PDGF group), in ${\alpha}-MEM$ contained with 10% FBS treated with 15ng/ml of PDGF-BB(PDGF group) for 1, 2, 3 day respectively. And then each group was characterized by examining of the cell counting, MTT assay, collagen synthesis. The results were as follows. 1. In the analysis of cell proliferation by cell counting, both calcium sulfate group and calcium sulfate plus PDGF group showed no stastically significant difference compared to control group, but there was stastically significant difference between PDGF group and calcium sulfate group at 1, 2 day(P<0.05). 2. In the analysis of cell proliferation by MTT assay in calcium sulfate extracts, both calcium sulfate group and calcium sulfate plus PDGF group showed no stastically significant difference compared to control group, but there was stastically significant difference between PDGF group and calcium sulfate group at 2, 3 day, and between calcium sulfate plus PDGF group and calcium sulfate group at 2 day(P

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.1
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• pp.48-54
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• 2006

This study was conducted to investigate the effect of calcium and boron intakes on calcium utilization in ovariectomized (OVX) rats. Rats were divided into 9 groups and fed diets containing various levels of calcium $(0.1\%,\;0.5\%,\;1.5\%)$ and boron (0.5 ppm, 50 ppm, 100 ppm) for 4 weeks. The half of rats in each group were ovariectomized and the others were sham-operated. Rats were fed same diets for 8 weeks after operation. Feed intake and weight gain were significantly increased as the dietary calcium was increased and those of OVX group were higher than in sham-operated group. Feed efficiency ratio was significantly higher in OVX group than that in sham-operated one. With boron supplementation, serum calcium level was significantly increased in low-calcium group, but decreased in adequate/high-calcium group. In calcium balance, calcium intake was significantly increased with increasing levels of calcium and boron and higher in OVX group than that in sham-operated one. With increasing calcium intake, fecal and urinary calcium excretions were significantly increased. Urinary calcium excretion was significantly decreased with increment of boron intake. Apparent calcium absorption of adequate-calcium OVX group was the highest among the groups. Daily calcium retention was significantly increased as the dietary calcium was increased and that of high-calcium OVX group was higher than high-calcium sham-operated group. According to these results, the boron supplementation increased the calcium intake and decreased the urinary calcium excretion. Therefore, it could be suggested that the boron supplementation may be complementary to calcium nutrition and useful for bone health.

• Journal of the Korean Applied Science and Technology
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• v.33 no.3
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• pp.575-586
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• 2016

An experiment was carried out to determine the effect of cooling water treatment with ionized calcium on calcium content, extending the shelf-life and quality of fresh chicken meat in poultry slaughtering process. The subjects were divided into four groups: control (0% without ionized calcium) and treatment groups (0.5, 0.7, 0.9% ionized calcium). The results indicated that the cooling water treatment with ionized calcium exhibited the bacterial counts of $10^5CFU/cm^2$ in surface of chicken meat, and maintained the quality of fresh chicken meat with extending the shelf-life above seven days when compared with that of control group. The results found that the cooling water treatment with ionized calcium could produce the calcium enrichment of chicken meat as nine times higher in calcium content of chicken meat when compared with that of control group. pH, water holding capacity, TBARS (MDA mg/kg) in chicken meat via the cooling water treatment with ionized calcium showed 6.4, above 50, below 0.10, respectively, with preventing the oxidation of unsaturated fatty acids. Lightness ($L^*$) as a chicken meat color, shear force indicated above 60, below $1.70kg/0.5inch^2$, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.6
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• pp.1026-1034
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• 2002

The Purpose of this study was to identify calcium intake and cognition on calcium of adolescents in Busan area. Questionnaires including dietary habit, cognition on calcium, preference of calcium rich foods and diet record were developed. The questionnaires surveyed 285 adolescents consisted of 145 6th grade students (younger adolescents group, male: 72, female: 73) and 140 11th grade students (older adolescents group male: 66 female: 74). Adolescents appeared high cognition for function of calcium and milk but low cognition for nutrients related to absorption of calcium. Younger boy adolescents among them appeared the lowest score of cognition on calcium. The most preferred calcium rich foods in adolescents were ice-cream, laver and then yogurt whereas soybean and icefish dried appeared the lowest preference. Calcium intake of adolescents was 491.5~530.5 mg, 61.4~66.3% of RDA for Koreans, in female and 554.5~636.7 mg, 69.3~70.7% of RDA for Koreans in male. 64.9% of older girl adolescents showed calcium intakes under 66.7% of RDA for Koreans and this group also appeared less frequency of exercise than other group. Calcium intake of adolescents consisted of 44.6~53.3% from animal foods and 42.4~51.4% from plant foods. The adolescents consumed milk and milk products most, then vegetables and fishes as calcium source foods. Correlation analysis indicated that calcium intake was positively related to cognition on calcium of adolescents.

• Molecules and Cells
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• v.22 no.1
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• pp.51-57
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• 2006

Haloperidol is a classical neuroleptic drug that is still in clinical use and can lead to abnormal motor activity following repeated administration. However, there is little knowledge of how it triggers neuronal impairment. In this study, we report that it induced calcium ion influx via L-type calcium channels and that the elevation of calcium ions induced by haloperidol appeared to render hippocampal cells more susceptible to oxidative stress. Indeed, the level of cytotoxic reactive oxygen species (ROS) and the expression of pro-apoptotic Bax increased in response to oxidative stress in haloperidol-treated cells, and these effects were inhibited by verapamil, a specific L-type calcium channel blocker, but not by the T-type calcium channel blocker, mibefradil. These findings indicate that haloperidol induces calcium ion influx via L-type calcium channels and that this calcium influx influences neuronal fate.

• Korean Journal of Agricultural Science
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• v.46 no.4
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• pp.737-754
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• 2019

Peaches have soft tissues compared to other fruits and are vulnerable to softness, wounds, and loss of marketability due to the weak fruit hardness after harvest. It is necessary to develop a technology to improve the shelf-life of the fruit to expand the distribution of peaches. Calcium compounds and chitosan have an important role in improving the shelf-life of fruit by maintaining the hardness and reducing the respiration rate in peach fruits. In this study, to select useful compounds to improve the shelf-life of peaches, calcium citrate, calcium chloride, calcium nitrate, GH-Ca, OS-Ca, chitosan, and chitosan dissolved in calcium chloride were sprayed onto peach trees. The characteristics of the harvested fruits were investigated after the 'Kumhong' and 'Madoka' peach tree treatments. The hardness of the fruit was kept the highest with the combined treatment and remained high with the calcium citrate, chitosan and calcium nitrate treatments. Ethylene production and respiration were effectively inhibited by the GH-Ca and chitosan treatments. There was no significant difference in soluble solids content and acidity among the fruits treated with the chemicals. The coloration of the fruit skin was not delayed by the calcium and chitosan chemical treatments. Calcium compounds were increased in the fruits and leaves of the peach trees treated with the chemicals compared to the untreated ones. These results suggest that the calcium treatment extended the shelf-life by increasing the calcium content in the leaves and fruits of the peach trees.

• Journal of Nutrition and Health
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• v.36 no.2
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• pp.167-174
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• 2003

This study investigated associations between nutrient intake, lumbar bone mineral density (BMD) , and bone mineral content (BMC) among 33 ovariectomized women (mean age =47.2 y) . Forty-five premenopausal women participated as a control group. The BMD and BMC of the lumbar spine (L$_2$-L$_4$) were measured by dual energy x-ray absorptiometry. Nutrient intake was estimated by the convenient method and a quantitative food frequency questionnaire was designed for this study that included the most commonly consumed foods sources of calcium. Participants were asked to identify all daily physical activities, and the number of hours per activity. The participants were also grouped by calcium intake. The total calcium intake of all participants was estimated by dietary calcium intake and then the subjects were divided into quartiles to assess the lumbar BMD and BMC of the highest quartile and the lowest quartile of calcium intake. The ovariectomized women consumed 602 mg/d of calcium which is 86% of RDA. There were significant differences in lumbar BMD and BMC between control and ovariectomized group. Within ovariectomized group the highest quartile calcium intake group had significantly greater lumbar bone mineral density and bone mineral content than the lowest quartile calcium intake group. Correlation analysis revealed that the ALP was positively associated with calcium index in control women, while ALP was positively associated with energy intake in ovariectomized women. And body weight was positively correlated with the spinal BMD and BMC in all women. The spinal BMD was negatively associated with menarche age, number of child, and the age of last child delivery, and age in control women. However, neither menarche age nor the age of last child delivery were associated with both spinal BMD in ovariectomized women. These results confirmed that ovariectomized and low calcium intake is associated with poor bone mineral density. Energy and calcium intake and adequate body weight should be recommended in ovariectomized women to prevent osteoporosis.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.574-578
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• 2005

The purpose of the study is to research the proper conditions to prepare the calcium-alginate microspheres using a emulsion method. The calcium-alginate microspheres were prepared at distinct concentrations (alginate; 1%, 1.5%, 2% (w/v), calcium chloride; 2%, 4%, 8%, 10%(w/v)). The shape of the microspheres prepared was spherical. With increasing alginate and calcium chloride concentration the mean size of the microspheres decreased gradually. In release test, the amount of ovalbumin released from the calcium-alginate mcirospheres was decreased by the increasing of alginate and calcium chloride concentration. In this study the best result was obtained at a 2% of alginate concentration and 10% of calcium chloride concentration.

• Korean Journal of Veterinary Research
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• v.44 no.3
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• pp.469-473
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• 2004

This study was performed to investigate the effects of calcium administration on the blood coagulation mechanism through APTT in the calf. Five male calves (70~90 kg) were used in this experiment. In the control group, heparinized normal saline (1 IU/kg/min) had been infusing into the jugular vein for 100 minutes. For the analysis of calcium effects on the APTT, the same solutions had been infusing during the first 40 minutes, subsequently the solution including calcium gluconate (3.3 mg/ml/min) had been infusing for 60 minutes. Blood samples were serially collected every 10 minutes for the APTT and platelets count and every 20 minutes for the calicum level during the infusion. In the calcium-treated group, after 70 minutes the APTT ratio (APTT heparin/APTT baseline) was higher than the therapeutic range. APTT was significantly increased at 50, 60 and 70 minutes in the calcium-treated group as compared to the control group (p<0.01). In the control group, calcium level was decreased significantly after heparin infusion (p<0.01). The platelet count was gradually decreased without significant variation in the both control and calcium-treated groups. These results suggested that APTT is slightly increased in combined heparin and calcium administration.