Microstructure of SiO2−Al2O3−CaO−P2O5−K2O−F-Glass Ceramics. 2. Time Dependence of Apatite Crystal Growth

2001 ◽  
Vol 13 (4) ◽  
pp. 1320-1325 ◽  
Author(s):  
Thomas Höche ◽  
Cornelia Moisescu ◽  
Issak Avramov ◽  
Christian Rüssel ◽  
Wolfgang D. Heerdegen ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Time Dependence ◽  
Glass Ceramics ◽  
Apatite Crystal

Control of apatite crystal growth in a fluoride containing amelogenin-rich matrix

Biomaterials ◽  
2005 ◽  
Vol 26 (13) ◽  
pp. 1595-1603 ◽  
Author(s):  
M. Iijima ◽  
J. Moradian-Oldak
Keyword(s):  
Crystal Growth ◽  
Apatite Crystal

Effects of Cr2O3 and CaF2 on the structure, crystal growth behavior, and properties of augite-based glass ceramics

2019 ◽  
Vol 39 (14) ◽  
pp. 4283-4291 ◽  
Author(s):  
Shuai Zhang ◽  
Yanling Zhang ◽  
Jintao Gao ◽  
Zhenmin Qu ◽  
Zheng Zhang
Keyword(s):  
Crystal Growth ◽  
Glass Ceramics ◽  
Growth Behavior ◽  
Crystal Growth Behavior

Crystallization Behavior and Optical Properties of Glass-Ceramics Containing Nano-Diopside Crystals

2020 ◽  
Vol 12 (4) ◽  
pp. 510-515
Author(s):  
Byeongguk Kang ◽  
Seunggu Kang
Keyword(s):  
Crystal Growth ◽  
Glass Ceramic ◽  
Crystallization Behavior ◽  
Building Materials ◽  
Red Light ◽  
Glass Ceramics ◽  
Nucleating Agent ◽  
Light Transmittance ◽  
Excitation Light ◽  
Bulk Crystallization

Diopside is a ceramic material with excellent properties including a low dielectric constant, high thermal conductivity, low sintering temperature below 1000 °C, and high mechanical strength. It has been applied to wireless and optical communications, substrates for touch panels, lenses for UV-LED, building materials, and so on. In this study, glass-ceramics containing nano-sized diopside crystals were fabricated, and their transmittance at visible light and photoluminescence were evaluated. In particular, TiO2 was added as a nucleating agent to suppress the surface crystallization phenomenon and Mn was used as a dopant to emit red light. The glass-ceramics were prepared by heat treatment at a temperature lower than the maximum crystal growth temperature (TP) calculated from the non-isothermal analysis method using differential thermal analysis (DTA) for the formation of nano-sized crystals. For glass containing 20 wt% of TiO2, the Avrami constant was calculated to be 2.23 and the activation energy required for crystal growth to be 549 kJ/mol, reflecting typical bulk crystallization behavior. Glass-ceramics with high light transmittance up to 70% were obtained by inducing the bulk crystallization behavior, and the diopside crystal size was less than 10 nm, which was equal to or higher than that of commercialized transparent glass-ceramic products. Glass-ceramic specimens doped with Mn showed luminescence of 736∼766 nm wavelength at excitation light of 365 nm wavelength. The emission peak intensity increased with the amount of dopant added, but gradually decreased with increasing crystallinity of the diopside phase.

Possible Roles of Partial Sequences at N- and C-termini of Amelogenin in Protein-Enamel Mineral Interaction

1989 ◽  
Vol 68 (9) ◽  
pp. 1331-1336 ◽  
Author(s):  
T. Aoba ◽  
E.C. Moreno ◽  
M. Kresak ◽  
T. Tanabe
Keyword(s):  
Crystal Growth ◽  
Adsorption Isotherm ◽  
Inhibitory Activity ◽  
Solid Phase ◽  
Ionic Composition ◽  
Significant Inhibition ◽  
Apatite Crystal ◽  
Supersaturated Solution ◽  
Adsorption Sites ◽  
Adsorption Affinity

The purpose of this study was to assess the functional significance of homologous sequences of mammalian amelogenins at their N- and C-termini. A porcine 5-kDa fragment corresponding to the N-terminal 45 residues of amelogenins was purified from the secretory enamel. The decapeptide TDKTKREEVD corresponding to the C-terminal 10 residues of amelogenins was synthesized according to conventional solid-phase procedures. The inhibitory activity of both moieties on apatite crystal growth was determined in a supersaturated solution having an ionic composition similar to that of the fluid phase separated from porcine secretory enamel. The 5-kDa amelogenin fragment was sparingly soluble in neutral solutions and (in condensed forms because of aggregation) showed no significant inhibition of crystal growth, whereas the fragment molecules pre-adsorbed onto the seed crystals yielded modest inhibition of hydroxyapatite precipitation. However, their inhibitory activity was significantly lower than that of parent porcine amelogenin (25-kDa molecular mass). The high solubility of synthesized decapeptide allowed us to determine the adsorption isotherm onto hydroxyapatite at 37°C, at an ionic strength similar to that of the enamel fluid. The obtained adsorption isotherm was described by a Langmuir model; the adsorption affinity and the maximum adsorption sites were 6.2 mL/μmol and 0.53 μmol/m2, respectively. As expected from the low adsorption affinity, the peptide showed a much weaker inhibition of apatite crystal growth than the parent amelogenin. All the foregoing results suggest that the adsorption onto apatite crystals and any inhibition of crystal growth by the amelogenin macromolecules cannot be associated with either partial molecular sequence, but may be determined by the whole molecular structure, including both segments at the N- and C-termini.

Formation and Crystal Growth of Needle-Like Fluoroapatite in Glass Ceramics

2007 ◽  
Vol 13 (S03) ◽  
Author(s):  
F Krumeich ◽  
R Nesper ◽  
C Ritzberger ◽  
E Apel ◽  
V Rheinberger ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Glass Ceramics

scholarly journals Effect of heat treatment temperature to the crystal growth and optical performance of Mn3O4 doped α-Zn2SiO4 based glass-ceramics

2019 ◽  
Vol 15 ◽  
pp. 102569
Author(s):  
Mohd Hafiz Mohd Zaid ◽  
Khamirul Amin Matori ◽  
Sidek Hj Ab Aziz ◽  
Halimah Mohamed Kamari ◽  
Yap Wing Fen ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Crystal Growth ◽  
Heat Treatment Temperature ◽  
Glass Ceramics ◽  
Treatment Temperature ◽  
Optical Performance

High-Resolution Electron Microscopy Study of Enamel Crystal Growth in Human Foetus

1990 ◽  
Vol 48 (1) ◽  
pp. 50-51
Author(s):  
F.J.G. Cuisinier ◽  
P. Steuer ◽  
J.C. Voegel ◽  
R. M. Frank
Keyword(s):  
Electron Microscopy ◽  
Crystal Growth ◽  
High Resolution ◽  
Dental Enamel ◽  
Optical Diffraction ◽  
Apatite Crystal ◽  
Specimen Holder ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Enamel Crystal

The mineral component of human dental enamel is formed by nonstoichiometric carbonated hydroxyapatite crystals. The presence of relatively large amounts of impurities in mature enamel crystals as well as their external shape are related to their growing mechanism. Enamel crystal growth was investigated previously directly with low resolution electron microscopy or by comparison with synthetic apatite crystal growth. The growing process of enamel crystals is still unknown and the aim of this study was to investigate foetal enamel growth during secretory stage by high resolution transmission electron microscopy.Developing enamel from 5 month-old human foetuses was fixed for 3 hours in a 2% glutaraldehyde and 2% paraformaldehyde solution in 0.1 M sodium cacodylate buffer. After 2 hour postfixation in 1% OsO4 in the same buffer and embedding in Epon, non decalcified ultrathin sections were obtained with a Sorvall-Porter MT-2C microtome equipped with a diamond knife and floated on demineralized water saturated against hydroxyapatite (200mg/l). The sections were observed in a Philips EM 430 transmission electron microscope operating at 300 kV equipped with a double tilt specimen holder. This microscope possessed a Sherzer resolution of 0.19 nm and the absence of drift and astigmatism was checked for each micrograph by an optical diffraction.

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