Formation of CaHPO4 · 2H2O from Enamel Mineral and Its Relationship to Caries Mechanism

1975 ◽  
Vol 54 (3) ◽  
pp. 475-481 ◽  
Author(s):  
W.E. Brown ◽  
P.R. Patel ◽  
L.C. Chow
Keyword(s):  
Calcium Phosphate ◽  
Tooth Enamel ◽  
Ph Values ◽  
Enhanced Solubility ◽  
Apatitic Phase

Tooth enamel, when treated with dilute H3PO4 solutions, dissolved incongruently with formation of large CaHPO4 · 2HO2O crystals. Equilibrated solutions were saturated with respect to CaHPO4 · 2H2O, and a mineral more soluble than well-crystallized, synthetic Ca5(PO 4)3OH, probably an impure, defective apatite. The CaHPO 4·2H2O crystals formed at considerably higher pH values than expected because of enhanced solubility of the apatitic phase in enamel. Pyrolysis of carious enamel revealed the presence of acidic calcium phosphate presumed to be CaHPO4·2H2O.

The Rebinding Properties of Bovine Serum Albumin Imprinted Calcium Phosphate/Polyacrylate/Alginate Hybrid Polymer Microspheres

2010 ◽  
Vol 152-153 ◽  
pp. 1636-1640 ◽  
Author(s):  
Kong Yin Zhao ◽  
Jun Fu Wei ◽  
Jin Yang Zhou ◽  
Yi Ping Zhao ◽  
Guo Xiang Cheng
Keyword(s):  
Calcium Phosphate ◽  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Bovine Serum ◽  
Polymer Microspheres ◽  
Hybrid Polymer ◽  
Ph Values ◽  
Factors Influencing ◽  
Recognition Property ◽  
Template Protein

Calcium phosphate/polyacrylate/alginate hybrid polymer microspheres with bovine serum albumin (BSA) embedded and coated on the surface were prepared with (NH4)2HPO4, sodium polyacrylate (SPA) and sodium alginate (SA) via Ca2+ crosslinking in inverse suspension. Rebinding behaviors of the microspheres were evaluated. The factors influencing the imprinting efficiency (IE) of imprinted microspheres were also studied, including the concentration of CaCl2, template content and pH values in rebinding solutions. Selectivity tests showed that the imprinted microspheres exhibited good recognition property for the template protein.

Phosphate Precipitation in Biofilms and Flocs

1983 ◽  
Vol 15 (3-4) ◽  
pp. 65-85 ◽  
Author(s):  
Erik Arvin ◽  
Gert Holm Kristensen
Keyword(s):  
Mathematical Model ◽  
Calcium Phosphate ◽  
Carbon Source ◽  
Practical Interest ◽  
Calcium Bicarbonate ◽  
Fixed Film ◽  
Phosphate Phase ◽  
Film Reactor ◽  
Calcium Phosphate Precipitation ◽  
Apatitic Phase

The experiments have confirmed that denitrification in biofilms may lead to calcium phosphate precipitation inside the biofilms due to the increased pH created by the denitrification reaction. This has been shown in a laboratory fixed film reactor with well defined geometry and feed with well defined substrates. The phosphate precipitate was in one case found similar to a carbonate containing apatitic phase. It accumulated in the bio-film to 9.3% P based on dry solids. A mathematical model has been developed relating the phosphate to nitrate molar removal rates to the concentration of phosphate, calcium, bicarbonate, the solubility of the solid phosphate phase and the type of carbon source used for denitrification. The model was supported by the experiments. The experiments show that the biofilm precipitation may be of significant practical interest, but factors as filamentous growth on the biofilm surface or precipitation of an easy soluble amorphous calcium phosphate can also make the biofilm precipitation insignificant. The precipitation effect is expected to be feasible in floes, if a homogeneous biomatrix with a thickness of more than approx. 100 µm exist in the floc substructure.

Effect of Macrophage on Degradation of β-TCP Ceramics

2005 ◽  
Vol 288-289 ◽  
pp. 549-552
Author(s):  
Shi Pu Li ◽  
Hong Lian Dai ◽  
Yu Hua Yan ◽  
Xian Ying Cao ◽  
Qi Xin Zheng
Keyword(s):  
Calcium Phosphate ◽  
Carbonic Anhydrase ◽  
Tricalcium Phosphate ◽  
Culture Medium ◽  
Calcium Phosphate Ceramics ◽  
Sem Observation ◽  
Ph Values ◽  
Calcium And Phosphorus

Mice macrophages which were mixed with β-tricalcium phosphate (β-TCP) ceramics powder were cultured, both calcium and phosphorus concentrations in the culture medium were evidently higher than that of β-TCP ceramics powder without cells. The microscope and SEM observation showed that macrophages wrapped β-TCP particles, and then phagocytized them into cytoplasm. The pH values inside and outside macrophage in β-TCP-bearing were tested. The histochemistry observation showed that there were many carbonic anhydrase positive grains in the cytochylema of macroghage after β-TCP ceramics powder being implanted. TEM investigation indicated that many β-TCP particles were phagocytized into the cytochylema of macroghage, and then vacuole was found after particles had degraded. The results showed that macrophages could take part in the degradation of calcium phosphate ceramics in two different ways.

Heat stability of milk: influence of colloidal calcium phosphate and β-lactoglobulin

1975 ◽  
Vol 42 (3) ◽  
pp. 427-435 ◽  
Author(s):  
P. F. Fox ◽  
M. C. T. Hoynes
Keyword(s):  
Calcium Phosphate ◽  
Fold Increase ◽  
Heat Stability ◽  
Protein Charge ◽  
Ph Values ◽  
Colloidal Calcium Phosphate ◽  
Maximum Stability ◽  
Ph Range ◽  
Ph Curve ◽  
Β Lactoglobulin

SummaryReduction of the level of colloidal calcium phosphate (CCP) progressively increased the heat stability of milk at pH values <~7·0 and increased the pH of maximum stability. Removal of 40% CCP also stabilized the system at the pH of minimum stability, but removal of ≥60% CCP rendered milk very unstable at pH values >7·2, an effect not offset by a 4-fold increase in κ-casein concentration. Doubling CCP had a slight destabilizing effect in the pH range 6·5–7·5.Addition of β-lactoglobulin to serum protein-free casein micelles had a marked destabilizing effect at pH values > ~6·8, but increased stability in the pH range 6·4–6·8. β-Lactoglobulin had a similar and more apparent effect on the heat stability of Na caseinate dissolved in milk diffusate.It is suggested that rather than being a stabilizing factor responsible for the maximum in the heat stability-pH curve, the true effect of β-lactoglobulin is to shift the curve to more acid pH values (reason unknown) and to sensitize the caseinate system to heat-induced Ca phosphate precipitation at pH values > ~7·0. Low stability at ~pH 7·0 introduces an apparent maximum in the heat stability-pH curve at ~pH 6·8, but this has no independent existence. At pH values >7·2, increased protein charge more than off-sets the influence of heat-precipitated CCP and stability again increases in micellar but not in soluble casein systems.

The heat stability of milk as affected by variations in pH and milk salts

1969 ◽  
Vol 36 (3) ◽  
pp. 343-351 ◽  
Author(s):  
P. A. Morrissey
Keyword(s):  
Calcium Phosphate ◽  
Calcium Ion ◽  
Narrow Range ◽  
Heat Stability ◽  
Salt Composition ◽  
Ion Concentrations ◽  
Ph Values ◽  
Soluble Calcium ◽  
Β Lactoglobulin ◽  
Minimum Heat

SummaryThe maximum and minimum heat stability exhibited by most milks over a relatively narrow range of pH values is shown also by synthetic colloidal calcium caseinate-calcium phosphate systems and even by simple caseinate systems, provided all possess adequate contents of β-lactoglobulin, soluble calcium and phosphate. The phenomenon is not, however, dependent on the presence of the characteristic micellar structure of the casein of milk. The minimum stability observed, usually around pH 6·9, is the most characteristic feature of the phenomenon and arises from heat induced deposition of calcium phosphate on a caseinate/β-lactoglobulin complex. This reaction, which tends to occur to a marked degree at relatively high pH values and calcium ion concentrations, sensitizes the complex to precipitation by calcium ions. The precise pH values at which the maximum and minimum stabilities occur can vary depending on the salt composition of the serum, since the latter can influence the solubility of calcium phosphate.

Scanning Electron Microscopic and Electrophoretic Studies on Clotting Factor Adsorbents

1976 ◽  
Vol 36 (01) ◽  
pp. 060-070
Author(s):  
S. L. M Deacon ◽  
R. M Howell
Keyword(s):  
Calcium Phosphate ◽  
Barium Sulphate ◽  
Clotting Factor ◽  
Clotting Factors ◽  
Electron Microscopic ◽  
Ph Values ◽  
Scanning Electron Microscopic ◽  
Definition Of ◽  
A Charge ◽  
Scanning Electron

SummaryPhysical studies carried out on a range of protein and clotting factor adsorbents revealed marked morphological and charge differences. Their appearance in the scanning electron microscope could be used to classify the insoluble precipitates, calcium phosphate, barium sulphate and citrate, as either amorphorous or crystalline.Surface charge is difficult to define but the present studies on the sparingly-soluble salts, based on calcium and barium, have revealed that they can be subdivided on the basis of the presence or absence of a charge reversal point in the pH-mobility curve. The anion component appeared to determine this characteristic; it was noted that phosphate and citrate ions had a marked effect and gave a biased negative potential at all pH values. We concluded that where a divalent cation is cohabiting with a trivalent anion, the greater potential-determining ability of the latter will dominate the overall charge at the surface of a particle, even below pH7 and the absence of a positive potential gives a monophasic pH-mobility curve.Differences in both the physical appearance and electrophoretic mobility of the adsorbents studied reflect the wide variation in their chemical composition, especially among the various forms of calcium phosphate which, unlike barium sulphate, can include substituted ions such as hydroxyl, in their crystal lattice. The definition of these characteristics allows their behaviour towards clotting factors to be more easily predicted.

Evaluation of Dentin Tubule Sealing Rate Improved by Attaching Ultrathin Amorphous Calcium Phosphate Sheet

2014 ◽  
Vol 631 ◽  
pp. 258-261 ◽  
Author(s):  
Nobuhiro Kato ◽  
Arata Isai ◽  
Ei Yamamoto ◽  
Hiroaki Nishikawa ◽  
Masanobu Kusunoki ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Amorphous Calcium Phosphate ◽  
Tooth Enamel ◽  
Dental Enamel ◽  
Gingival Recession ◽  
Dentin Hypersensitivity ◽  
Mechanical Stimuli ◽  
Dentin Tubule ◽  
Human Dentin ◽  
Dentin Tubules

Dentin hypersensitivity is induced by mechanical stimuli or heat stimuli applied via dentin tubules exposed by lost of dental enamel or gingival recession. Common treatments for dentin hypersensitivity are resin coating or laser irradiation. However, these treatments have some problems such as poor biocompatibility or insufficient durability. We have been developing a treatment that creates artificial tooth enamel by attaching flexible ultrathin calcium phosphate sheet having a crystal structure similar to that of tooth enamel to seal the dentin tubules. In this study, the quantitative evaluation of dentin tubule sealing rate improved by attaching ultrathin amorphous calcium phosphate (APC) sheet on human dentin is presented. The obtained sealing-rate by APC sheet application was 70.9 ± 4.8 %.

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