• Applied Biological Chemistry
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• v.40 no.6
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• pp.531-535
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• 1997

An efficient process for recovery of calcium from the eggshell was developed and some organic acids were used in an attempt to enhance the degree of calcium ionization. Eggshell membrane was readily separated from crushed eggshell based on the differences in specific gravities. The conditions which allowed most efficient membrane removal were found to be 30 rpm of speed, 30 min of residence time and 0.08 of volume fraction. It took 3 hours for the eggshell powder prepared at $1000^{\circ}C$ to reach L value of 90 with the Hausner ratio being 1.43. The calcium ion concentrations were 990, 3500, 3900 and 4200 ppm in pure water, acetic acid, citric acid and lactic acid$(0.05{\sim}3%)$ aqueous solution, respectively. The degrees of ionization of calcium-citrate-malate complex(CCM), calcium-citric acid complex(CC) and calcium malic acid complex(CM) increased by 4 to 5 times compared to eggshell calcium powder.

• The Korean Journal of Community Living Science
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• v.16 no.1
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• pp.59-64
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• 2005

This study is to find out effects of hot water soluble extract from green tea, one of the Korean favorites, on the calcium metabolism and bone strength in body. To do so, calcium, phosphate, creatinine concentration and ALP activity in blood and the content of calcium and ash in the organ, the length, weight, strength in bone were measured. In addition, to find the calcium metabolism, the level of calcium intake, excretion, retention were measured. Twenty male Sprague-Dawley rats were divided into two groups and isoloated soy protein was provided as the source of protein and CaCO₃ was provided as the source of calcium. 0.5% hot water soluble extract from green tea was provided to the green tea groups and for the control group deionized water was provided. The results are as follows ; 1. There is no difference between the experimental groups in diet intake, weight gain, and the feed intake. 2. Feed efficiency ratio was low in the group which hot water soluble extract from green tea was provided. 3. There is no difference between groups the level of calcium, phosphorus, creatinine and ALP activity in serum. 4. There is no difference between groups weight, contents of ash and calcium in kidney and liver. 5. There is no difference between groups in calcium intake, absorption, excretion, and retention. 6. There is no difference between groups weight, length and strength in bone. In summary, when hot water soluble extract from green tea was provided with the amount of 150-200mg, which is taken when people generally drink as favorite tea, weight gain was reduced due to the decrease of feed efficiency ratio. However, it did not affect the availability of calcium in body at all. Thus, even if a big quantity of green tea powder or solid of hot green tea extract is not provided, the quantity obtained when people drink green tea lowers the feed efficiency ratio without reducing availability of calcium in body.

• Research in Community and Public Health Nursing
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• v.16 no.1
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• pp.77-85
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• 2005

Purpose: This study was to determine the effects of calcium intake on bone mineral density (BMD) in pre and post menopause women and to provide basic data for enhancing bone health of middle aged women. Methods: A total of 700 middle-aged women living in Seoul and Geonggi Province were interviewed during the period from June 2003 through January 2004 to investigate their social. demographic and physiological characteristics, health and daily activity performance, and their dietary patterns, and bone mineral density was measured. The survey of dietary intake was 24 hour recalls, and the individual calcium intake was calculated using food frequency. Data of 618 subjects was used for the analysis. Of the calcium intake levels, BMD values of the subjects of 20% of high level. 60% of middle level and 20% of low level were analyzed and compared. Results: The level of calcium intake according to general characteristics of the subjects was significantly related to age (p=0.001), education levels (p=.003) and marital status (p=.001). The BMD of the lumbar vertebrae and femur of the subjects taking a high level of calcium showed significantly higher than that of the subjects taking a middle level and low level of calcium. Femoral T-score was also significantly higher in subjects taking a high level of calcium than that of those taking a middle level and lower levels of calcium. Lumber spine T-score was higher in the high level group than that of the middle level group. Conclusion: The study revealed that women taking a high level of calcium had better bone health. Therefore. calcium intake is extremely important in daily dietary intake so that the intake of calcium-rich foods is highly recommended.

• The Korean Journal of Pharmacology
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• v.22 no.2
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• pp.135-143
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• 1986

This study was designed to investigate the role of calcium in the function of an isolated perfused rabbit kidney and its effect on the diuretic action of furosemide. The administrations of hydralazine and verapamil produced remarkable diuretic actions mainly by decreasing renal resistance. The administration of furosemide in combination with hydralazine or verapamil produced remarkable diuretic action and there was no difference between the two groups. The administration of quinidine produced a diuretic action in spite of vasoconstriction and potentiated the diuretic action of furosemide. In the calcium-free perfusion medium, the administration of calcium produced a marked diuretic action in spite of vasoconstriction and potentiated significantly the diuretic action of furosemide. The administration of quinidine did not alter renal function and the diuretic action of furosemide, but the combined administration of quinidine and calcium showed antidiuretic effect due to excessive vasoconstriction in the calcium-free perfusion medium. Although the administration of verapamil produced a slight diuretic action in the calcium-free perfusion medium, verapamil did not alter the diuretic action of calcium as well as the diuretic actions of furosemide alone and in combination with calcium. The results of this experiment show that calcium, verapamil and quinidine produced diuretic actions and calcium potentiates the diuretic action of furosemide.

• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.379-390
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• 1998

In endodontic treatment, calcium hydroxide has been used as intracanal medicament. Although calcium hydroxide should be removed thoroughly before permanent root canal filling, no effective method for its removal has been reported. Because of irregularity of root canal walls, root curvatures and anatomic variations, it is insufficient to remove calcium hydroxide from the canal wall only by mechanical instrumentation Considering the chemical effects of irrigants on calcium hydroxide, $Ca^{++}$ dissolving effect from two calcium hydroxide products is investigated, using dis- tilled water, NaOCl, citric acid and EDTA. Vitapex$^{(R)}$ 0.1g and calcium hydroxide 0.03g were dissolved in distilled water, 5% NaOCl, 50% citric acid and 17% EDTA respectively, at 1, 3, 5, 10min. time interval. The solution was filtered using filter paper(pore size $5{\mu}m$) and $Ca^{++}$ concentration was determined by ion chromatography. The result were as follows : 1. Distilled water, NaOCl, citric acid and EDTA abstracted more $Ca^{++}$ from calcium hydroxide than Vitapex$^{(R)}$ except NaOCl 1, 5, 10 time interval. 2. EDTA and citric acid abstracted more $Ca^{++}$ from Vitapex$^{(R)}$ and calcium hydroxide than distilled water or NaOCl. The overall result support the view that water-based calcium hydroxide product is easily removed than oil-based calcium hydroxide product and EDTA, citric acid are more effective in $Ca^{++}$ elution than NaOCl or distilled water.

• Journal of the Korean Society of Food Culture
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• v.36 no.6
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• pp.595-606
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• 2021

Unhealthy dietary behavior such as insufficient calcium intake can be one of risk factors of osteoporosis and chronic diseases in older people. This study evaluated the recent trends in dietary calcium intake and the food source in Korean adults aged 50 years or older using the Korea National Health and Nutrition Examination Survey (KNHANES, 2015-2019) data. This study used 24-hour recall survey data to investigate the calcium intake, the major food groups and main dishes contributing to the calcium intake. The mean calcium intake was 479.55-506.81 mg/day. The major food groups that contribute to calcium intake were vegetables, milks and fishes. Dairy and frozen desserts and kimchi were the major dish groups that contributed to the calcium intake. Calcium intake from milk in dairy and frozen dessert group has been high in last 5 years (50-64 years old: 34.71-47.68 mg, 65-74 years old: 29.72-43.65 mg, over 75 years old: 22.91-42.93 mg). In addition, baechu-kimchi is the most contributed to the calcium intake in kimchi group (50-64 years old: 35.10-41.47 mg, 65-74 years old: 29.62-34.96 mg, over 75 years old: 23.79-29.13 mg). In conclusion, various source of calcium needs to be recommended to increase intake calcium in over 50 years, which may reduce chronic diseases and improve quality of life.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.6
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• pp.841-849
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• 2023

Corallina pilulifera (CP) is prevalent along the Korean coastline and belongs to the Corallinaceae family, exhibiting growth throughout all seasons. This study confirmed the role of calcium supplementation through CP, calcined CP (CCP), and a commercial calcium powder, highlighting variations in dosage within animal models induced by a calcium-deficient diet. Analysis of calcium absorption was conducted by assessing the serum and urine calcium levels during the feeding periods. Serum calcium content was significantly higher in the control group (CON, 9.79 mg/dL) than in the calcium-deficient model (CDM, 6.15 mg/dL). The calcium content of urine was significantly higher than that of CON (0.20 mg/dL) compared with CDM (0.08 mg/dL). Reticular bone thickness showed no significant differences between the CON and CDM groups. Additionally, micro-CT results demonstrated a reduction in the trabecular volume and a significant difference between the number of strands and the average interval of the reticular bone. In conclusion, CP serves as a promising source of calcium supplementation. Therefore, these findings emphasize that CP is of sufficient value as an industrial material related to calcium metabolism.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.20 no.3
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• pp.217-227
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• 1998

Calcium sulfate(plaster of Paris) has been used in dental and orthopedic surgery for about 100 years. It is well known that the plaster is bioresorbable, biocompatible, defect conformable and moldable. The purpose of this study is to evaluate two effects of calcium sulfate on bone regeneration, that is, the effects of graft materials and barrier for bone regeneration. Cortical bone defects were formed for recipient site on the femurs of 19 Sprague-Dawley rats. The autogenous particulated bone and calcium sulfate were grafted to the defects. Calcium sulfate paste, $Gore-Tex^R$ membrane(W.L. GORE & ASSOCIATES LTD., U.S.A.) and rubber sheet were used for the shielding materials. The results were as follows : 1. Calcium sulfate that had been grafted in the cortical bone defect was almost resorbed before bone remodeling, resultantly had little effect on bone regeneration. 2. Resoption process of calcium sulfate grafted on the bone grafting area tends to be accelerated, as being divided into numerous small particles progressively. Under the situation where the calcium sulfate was protected, with the coverage of fascia, $Gore-Tex^R$ membrane or rubber sheet, new bone formation was confirmed with presence of calcium sulfate particles over 6 weeks after grafting. 3. In the case of calcium sulfate covered with membrane, distinct bone formation was observed on the marrow space of femur adjacent to the plaster mass. 4. Rubber shielded plaster group revealed new bone trabeculae under the rubber sheet, but it showed ischemic degeneration of superficial cortical bone.

• 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.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.2
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• pp.171-176
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• 2000

The phosphatic calcium compounds such as calcium hydrogen phosphate, bone ash, hydroxyapatite and tricalcium phosphate were prepared using the high purity calcium hydroxide and calcium carbonate obtained from shell resources. Calcium hydrogen phosphate had been prepared using the high purity calcium hydroxide and phosphoric acid solution. Using the calcium hydrogen phosphate as a starting materials, bone ash have been prepared by solid state reaction method and hydroxyapatite could be obtained by hydrothermal treatment method, respectively. The tricalcium phosphate was prepared by the solid state reaction of a stoichiometic mixture of bone ash and high purity calcium carbonate. In this paper, the optimal preparation process and conditions of phosphatic calcium compounds were established.