Effect of thermal and densification processes on reaction and conventional sinterings of a hydrolyzed calcium phosphate phase

2021 ◽  
Author(s):  
Z. Zyman ◽  
M. Epple ◽  
A. Goncharenko ◽  
M. Tkachenko ◽  
D. Rokhmistrov ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Phosphate Phase ◽  
Calcium Phosphate Phase

Evidence of calcium phosphate supersaturation in the loop of Henle

1996 ◽  
Vol 270 (4) ◽  
pp. F604-F613 ◽  
Author(s):  
J. R. Asplin ◽  
N. S. Mandel ◽  
F. L. Coe
Keyword(s):  
Calcium Phosphate ◽  
Calcium Concentration ◽  
Loop Of Henle ◽  
X Ray ◽  
Ion Interactions ◽  
Collecting Ducts ◽  
Phosphate Phase ◽  
Dietary Phosphate ◽  
Calcium Phosphate Phase

We have used published rat micropuncture data to construct a matrix of ion concentrations along the rat nephron. With an iterative computer model of known ion interactions, we calculated relative supersaturation ratios in all nephron segments. The collecting ducts and urine showed expected supersaturation with stone-forming salts. Fluid in the thin segment of the loop of Henle may be supersaturated with calcium carbonate and calcium phosphate under certain conditions. Because calculations cannot predict the actual course of crystallization, we made solutions to mimic, in vitro, presumed conditions in the loop of Henle. The solid phases that formed were analyzed by X-ray powder diffraction, electron microprobe, and infrared spectroscopy. All samples were identified as poorly crystallized or immature apatite. The descending limb of Henle's loop creates a unique condition as it extracts water but not sodium, bicarbonate, calcium, or phosphate, giving a calcium concentration at the bend of 3 mM, pH 7.4, and a phosphate concentration that varies from 0.8 to 48 mM, depending on parathyroid hormone and dietary phosphate. We conclude that conditions in the thin segment potentially could create a solid calcium phosphate phase, which may initiate nucleation of calcium oxalate salts in the collecting ducts, potentiating nephrolithiasis and nephrocalcinosis.

The uptake of strontium by calcium phosphate phase formed at an elevated pH

1996 ◽  
Vol 204 (2) ◽  
pp. 363-370 ◽  
Author(s):  
S. Raičević ◽  
Ž Vuković ◽  
T. L. Lizunova ◽  
V. F. Komarov
Keyword(s):  
Calcium Phosphate ◽  
Phosphate Phase ◽  
Calcium Phosphate Phase

Stabilizing amorphous calcium phosphate phase by citrate adsorption

CrystEngComm ◽  
2014 ◽  
Vol 16 (10) ◽  
pp. 1864-1867 ◽  
Author(s):  
Yan Chen ◽  
Wenjia Gu ◽  
Haihua Pan ◽  
Shuqin Jiang ◽  
Ruikang Tang
Keyword(s):  
Calcium Phosphate ◽  
Amorphous Phase ◽  
Amorphous Calcium Phosphate ◽  
Surface Reaction ◽  
Phosphate Phase ◽  
Calcium Phosphate Phase

Citrate controls nucleation by association with a precursor amorphous phase, which inhibits the surface reaction for nucleation.

Probable Phase Composition of the Mineral in Bone

1980 ◽  
Vol 35 (5-6) ◽  
pp. 357-362 ◽  
Author(s):  
F. C. M. Driessens
Keyword(s):  
Phase Composition ◽  
Calcium Phosphate ◽  
Bone Mineral ◽  
Experimental Error ◽  
Human Bone ◽  
Apatite Structure ◽  
Phosphate Phase ◽  
Limits Of Error ◽  
Calcium Phosphate Phase ◽  
Citrate Ions

Abstract Formulas proposed for the mineral of bone were reviewed. Literature data were collected where Ca, P, Na, Mg and CO3 are determined in the same samples. These data were analyzed for their conformity to the above mentioned formulas. According to this analysis Mg is contained in a phase having the Ca/P of magnesium whitlockite within the limits of error. Na is contained in a carbonated calcium phosphate phase which in analogy with synthetic systems must have the apatite structure. The Ca/P ratio of the remaining "rest phase" is 2. This is based on the composi­ tion of 101 bone mineral samples taken from fishes, reptiles, amphibians, birds and mammals. The CO3 content of the bone samples agrees with the formula Ca8 (PO4)4 (CO3) (OH)2 · x H2O for the "rest phase" within the limits of experimental error. Such a compound has, however, not been found in synthetic systems. Human bone contains about 15% magnesium whitlockite, 25% of the Na and CO3 containing apatite and the rest is the carbonated calcium phosphate with Ca/P = 2. It is presumed that this compound has a structure similar to that of octo calcium phosphate and that most of the citrate ions which always occur in bone mineral samples are in­ corporated in that phase.

scholarly journals In situ luminescence analysis: a new light on monitoring calcium phosphate phase transitions

2017 ◽  
Vol 4 (7) ◽  
pp. 1157-1165 ◽  
Author(s):  
H. Terraschke ◽  
M. Rothe ◽  
A.-M. Tsirigoni ◽  
P. Lindenberg ◽  
L. Ruiz Arana ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Calcium Phosphate ◽  
Synchrotron Radiation ◽  
Calcium Phosphates ◽  
High Sensitivity ◽  
Luminescence Analysis ◽  
Biologically Relevant ◽  
Phosphate Phase ◽  
Calcium Phosphate Phase

In situ luminescence measurements allow monitoring the phase transitions of biologically relevant calcium phosphates with high sensitivity, independent of synchrotron radiation.

Novel calcium phosphate ceramics prepared by powder sintering and crystallization of glasses in the pyrophosphate region

1998 ◽  
Vol 13 (12) ◽  
pp. 3357-3360 ◽  
Author(s):  
Toshihiro Kasuga ◽  
Yoshihiro Abe
Keyword(s):  
Calcium Phosphate ◽  
Glass Ceramics ◽  
Atomic Ratio ◽  
Phosphate Glasses ◽  
High Fracture Toughness ◽  
High Fracture ◽  
Powder Sintering ◽  
Phosphate Phase ◽  
Powder Compacts ◽  
Calcium Phosphate Phase

Silica-free phosphate glasses containing small amounts of Na2O and TiO2 with the composition of Ca/P = 1 in atomic ratio were obtained. When powder compacts of the glasses were heated at 850 °C, they crystallized and subsequently sintered, resulting in glass-ceramics containing β–Ca3(PO4)2 and β–Ca2P2O7 crystalline phases. The glass-ceramics show a relatively high fracture toughness of KIC ≈ 2 MPa m0.5. By soaking in simulated body fluid at 37 °C, a calcium phosphate phase was formed newly on the surface of the glass-ceramics.

The Growth of Calcium Phosphates on Hydroxyapatite Crystals. The Effect of Fluoride and Phosphonate

1978 ◽  
Vol 57 (5-6) ◽  
pp. 735-742 ◽  
Author(s):  
J.P. Barone ◽  
G.H. Nancollas
Keyword(s):  
Crystal Growth ◽  
Calcium Phosphate ◽  
Calcium Phosphates ◽  
Fluoride Ion ◽  
Dicalcium Phosphate Dihydrate ◽  
Phosphate Dihydrate ◽  
Phosphate Phase ◽  
Calcium Phosphate Phase ◽  
Basic Phase ◽  
Hydroxyapatite Crystals

The nature of the calcium phosphate phase which precipitates on hydroxyapatite seed crystals can be controlled by varying the HAP seed concentration. At low seed concentrations, dicalcium phosphate dihydrate (DCPD) is formed while at high seed levels a more basic phase precipitates. It has been found that fluoride ion increases the percentage of basic phase that crystallizes while ethylidenediphosphonic acid encourages the formation of DCPD. This behavior is explained by the competition between the nucleation of DCPD and the crystal growth on sites already present on the HAP seeds.

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