• Journal of the Korean Vacuum Society
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• v.7 no.s1
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• pp.30-36
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• 1998

The plasma-spray technique is currently the most frequently used method to produce calcium phosphate coatings. Hydroxyapatite(HAp), one form of calcium phosphate, is preferred by its ability to form a direct bond with living bone, resulting in improvements of implant fixation and faster bone healing. Recently, concerns have been raised regarding the viable use and long-term stability of plasma-spray HAp coatings due to its nature of comparatively thick, porous, and poor bonding strength to metal implants. Thin layers (maximum of few microns) of calcium phosphate were formed by an e-beam evaporation with and without ion bombardments. The Ca/P ration of film was controlled by either using the evaporants having the different ration of Ca/P with addition of CaO, or adjusting the ion beam assist current. The Ca/P ration had great effects on the structure formation after heat treatment and the dissolution bahavior. The calcium phosphate films produced by IBAD exhibited high adhesion strength.

• Journal of Practical Agriculture & Fisheries Research
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• v.6 no.1
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• pp.73-80
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• 2004

This study was conducted to determine the effect of several kinds of calcium foliar application and drip irrigation on the bitter pit incidence of apple. CaCl₂, inorganic calcium compound, was the most effective in increasing the calcium concentration in the fruit flesh, and reducing bitter pit incidence. Calcium spray in the later part of the growing season was more effective than in the earlier part. Drip irrigation applied during the dry spells increased calcium concentration in the fruit flesh, and reduced bitter pit incidence.

• Proceedings of the Korean Ceranic Society Conference
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• 2000.04a
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• pp.115.1-115.1
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• 2000

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.4
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• pp.743-746
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• 2000

The possiblity of sepiae os as a calcium supplement in food was studied. Elementary contents of sepiae os were as follows; Ca 53.254%, O 26.781%, Na 14.905%, Cl 4.37%, Sr 0.507%, P 0.068% and Si 0.051%, respectively. Most of calcium in sepiae os was present as a form of CaCO3. Sruface area of sepiae os was found as 386 m2/g, and scanning electron micrograph showed sepiae os has multilayer struture. Buffering capacity of sepiae os that of CaCO3. With above results, sepiae os can be used as a calcium supplement in food with good chacterateristics.

• Journal of Nutrition and Health
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• v.27 no.5
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• pp.473-482
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• 1994

This study was to compare the bioavailability of calcium from anchovy and tofu to those of calcium from calcium carbonate(CaCO3)as the control diet and non-fat dry milk(NFDM). Rats weighing 50-60g were placed on experimental diets and deionized water at free access for 4 weeks. Diets contained 0.2% calcium from calcium-carbonate, NFDM, anchovy, tofu or 0.5% calcium as obtained were as follows : 1) No significant differences in the apparent absorption of calcium(62.5%-71.0%) were observed in the rats fed four different calcium sources at the level of 0.2% while 0.5% calcium diet group apparently absorbed calcium less efficiently(52.2%). 2) Bone length of tibia and femur was not significantly different among the groups, though 0.5% calcium of control group showed slightly longer length. 3) Tibia fat-free dry weights of 0.2% calcium of NFDM and anchovy diet groups were not significantly different from that of 0.5% calcium of control group. For femurs NFDM, anchovy and tofu groups were similar in their fat-free dry weight to that of 0.5% calcium group. 4) For calcium contents tibia contents tibia from anchovy treated group showed higher value than calcium-carbonate and tofu groups and the value was not significantly different from that of 0.5% calcium group. In femur NFDM, tofu and calcium-carbonate groups were not significantly different in their calcium content but 0.5% calcium group had higher level of calcium than 0.2% calcium groups. 5) The normalized values(NV) show that there was no significant differences in NV among 0.2% CaCO3 anchovy and tofu groups, while NV of NFDM group was significantly lower than that of calcium-carbonate group. NV of 0.5% calcium group was a little more than 50% of those in 0.2% calcium groups. Though the values obtained for the calcium bioavailability were somewhat variable among experimental products, it was demonstrated that anchovy and tofu are as good as NFDM for the dietary calcium provider when calcium intake is at marginal level.

• Applied Biological Chemistry
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• v.28 no.2
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• pp.56-61
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• 1985

The mass balances of calcium salts during the manufacturing processes of Tofu were established by conductometric method and chemical analysis method. During the manufacturing processes of soy milk and Tofu, 66% of solid and 63% of calcium was transfered from soy-bean to the soy milk, and 47.8% of total solid from soybean was transfered to the Tofu, respectively. When the $CaCl_2$ was used as coagulant, calcium contents in Tofu $(Y_{Tofu},\;mg{\cdot}Ca/g{\cdot}Tofu,\;wet\;basis)$ and drained solution $(Y_{drained\;soln},\;mg{\cdot}Ca/ml{\cdot}drained\;soln.)$ were linearly increased with the amounts of $CaCl_2(C,g{\cdot}CaCl_2/ml{\cdot}soy\;milk)$ added in soy milk, and correlative equations between them were obtained as $Y_{Tofu}=0.3369\;C+1.2689$ for Tofu$(moisture\;content:\;81.5{\pm}0.5%)$ with r=0.9898, and $Y_{drained\;soln}= 0.2899C+0.0399$ for drained solution with r= 0.9991. It was proved that conductometric method was reasonably applicable to the measurement of calcium contents of the products from every processes of Tofu manufacture except soy-bean. However the conductometric method was not recomendable in the case of $CaSO_4$ as coagulant due to its low solubility ana uneven distribution in soy milk and Tofu tissue.

• Journal of the Korean Ceramic Society
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• v.37 no.5
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• pp.459-465
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• 2000

3CaO.3Al2O3.CaSO4(C4A3)clinker was prepared by solid state reaction and then its hydration property was investigated. C4A3 clinker was fired at various temperatures in the range of 700~135$0^{\circ}C$. The hydration of it was studied by XRD, DSC, Solid-state 27Al MAS NMR and SEM. According to the results, the Ca4A3 clinker was produced by reacting calcium aluminates with CaSO4 and Al2O3 and C4A3 was formed as a main phase after calcining at 120$0^{\circ}C$. The hydration products were mainly calcium monosulfoaluminate hydrate and Al(OH)3, and they were produced after 2hrs of hydration. However the hydration rate was about 74% at 3days.

• Toxicological Research
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• v.16 no.1
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• pp.63-66
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• 2000

The effects of acute ethanol on the high K+ induced $Ca^{2+}}$ signals were examined from primary cultures of cerebellar granule neurons. $Ca^{2+}}$ signals were measured with Calcium Green-1 based microscopic video imaging. Because $Ca^{2+}}$ signal was low in most of granule neurons without stimuli, high KCI was used for depolarization. In most case, acute exposure to ethanol reduced the peak amplitude of the $Ca^{2+}}$ signals, induced by high K+, even though low concentration of ethanol(2~10mM) was used and the effects lasted more than 30min. In was also possible to see differences of ethanol inhibition, i.e. the temporal pattern of $Ca^{2+}}$ signal reductions and the strength of inhibition of $Ca^{2+}}$ signals in cerebellar granule neurons. These results indicate that low concentration of ethanol has diverse actions on the $Ca^{2+}}$ signals in cerebellar granule neurons.

• Journal of the Korean Ceramic Society
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• v.50 no.4
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• pp.257-262
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• 2013

A biomimetic approach was applied for the chemical deposition of calcium phosphate (CaP) coatings on 3 mole% yttrium-stabilized zirconia [3YSZ] powders. The solid-state reaction of 3YSZ powders with the addition of CaP was investigated for the development of biodegradable zirconia ceramics. The solid-state interaction between the 3YSZ matrix powders and the CaP additives differed from the behavior of commercial zirconia matrix powders. The 3YSZ powders were chemically reacted with precursors for the CaP formation. 3YSZ powders were mixed in an aqueous solution of Ca-P precursors and the CaP was precipitated on the surface of the 3YSZ matrix powders. The CaP-doped YSZ powders were calcined at $1100^{\circ}C$ and shaped powder blocks were then fired at $1600^{\circ}C$ for 2 h. The CaP phase formation was investigated using FE-SEM and XRD analysis.

• Development and Reproduction
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• v.24 no.4
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• pp.297-306
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• 2020

Repetitive changes in the intracellular calcium concentration ([Ca²⁺]i) triggers egg activation, including cortical granule exocytosis, resumption of second meiosis, block to polyspermy, and initiating embryonic development. [Ca²⁺]i oscillations that continue for several hours, are required for the early events of egg activation and possibly connected to further development to the blastocyst stage. The sources of Ca²⁺ ion elevation during [Ca²⁺]i oscillations are Ca²⁺ release from endoplasmic reticulum through inositol 1,4,5 tri-phosphate receptor and Ca²⁺ ion influx through Ca²⁺ channel on the plasma membrane. Ca²⁺ channels have been characterized into voltage-dependent Ca²⁺ channels (VDCCs), ligand-gated Ca²⁺ channel, and leak-channel. VDCCs expressed on muscle cell or neuron is specified into L, T, N, P, Q, and R type VDCs by their activation threshold or their sensitivity to peptide toxins isolated from cone snails and spiders. The present study was aimed to investigate the localization pattern of N and P/Q type voltage-dependent calcium channels in mouse eggs and the role in fertilization. [Ca²⁺]i oscillation was observed in a Ca²⁺ contained medium with sperm factor or adenophostin A injection but disappeared in Ca²⁺ free medium. Ca²⁺ influx was decreased by Lat A. N-VDCC specific inhibitor, ω-Conotoxin CVIIA induced abnormal [Ca²⁺]i oscillation profiles in SrCl₂ treatment. N or P/Q type VDC were distributed on the plasma membrane in cortical cluster form, not in the cytoplasm. Ca²⁺ influx is essential for [Ca²⁺]i oscillation during mammalian fertilization. This Ca²⁺ influx might be controlled through the N or P/Q type VDCCs. Abnormal VDCCs expression of eggs could be tested in fertilization failure or low fertilization eggs in subfertility women.