Biomimetic Preparation of ha Precursors at 37°C in Urea- and Enzyme Urease-Containing Synthetic Body Fluids

1999 ◽  
Vol 599 ◽  
Author(s):  
D Bayraktar ◽  
A C. Tas
Keyword(s):  
Single Phase ◽  
Calcium Nitrate ◽  
Calcium Hydroxyapatite ◽  
Chemical Precipitation ◽  
Calcium Nitrate Tetrahydrate ◽  
Hydrogen Phosphate ◽  
Synthetic Bone ◽  
Nitrate Tetrahydrate ◽  
Phosphate Salts ◽  
Diammonium Hydrogen

AbstractAn important inorganic phase of synthetic bone applications, calcium hydroxyapatite (HA, Ca10(PO4)6(OH)2), was prepared as a single-phase and sub-micron bioceramic powder. Carbonated HA precursors were synthesized from calcium nitrate tetrahydrate and diammonium hydrogen phosphate salts dissolved in “synthetic body fluid” (SBF) solutions, containing urea (H2NCONH2) and enzyme urease, under the biomimetic conditions of 37°C and pH 7.4, by using a novel chemical precipitation technique.

Structural Analysis of Strontium-Substituted Hydroxyapatites

2012 ◽  
Vol 506 ◽  
pp. 210-213
Author(s):  
H. Paennarin ◽  
S. L. Seet
Keyword(s):  
Calcium Nitrate ◽  
Deionized Water ◽  
Wave Number ◽  
Calcium Nitrate Tetrahydrate ◽  
Hydrogen Phosphate ◽  
Xrd Study ◽  
Nitrate Tetrahydrate ◽  
Effects Of Ph ◽  
Ft Ir ◽  
Diammonium Hydrogen

In this work, the effects of pH on the formation of hydroxyapatite (HA) and Sr-substituted HA (Sr-HA) were studied. Calcium nitrate tetrahydrate and strontium acetate were dissolved in ethanol at the Ca:Sr mole ratio of 9.5:0.5. Diammonium hydrogen phosphate was dissolved in deionized water. The two solutions were mixed thoroughly and the ammonium solution was added in order to adjust the pH of the solution. After precipitation, the system was subjected to the heat until the dried powder was obtained and then calcined at 600°C for 2 h. From XRD study, HA was found as the main phase in all calcined powders. The substitution of Sr for Ca in HA structure was confirmed by the shift of XRD peak to lower angles and the shifts of OH to higher wave number and PO4 bands to lower wave numbers in FT-IR spectra.

The Influence of Synthesis Conditions on Hydroxyapatite Adsorption Characteristics in the Process of Zn(II) and Pb(II) Removal from Single and Binary Solutions

2018 ◽  
Vol 69 (4) ◽  
pp. 759-766
Author(s):  
Rodica Elena Patescu ◽  
Claudia Maria Simonescu ◽  
Gheorghe Nechifor ◽  
Christu Tardei ◽  
Ionela Camelia Ionascu
Keyword(s):  
Heavy Metal ◽  
Metal Ion ◽  
Calcium Nitrate ◽  
Chemical Precipitation ◽  
Isotherm Models ◽  
Calcium Nitrate Tetrahydrate ◽  
Binary Solutions ◽  
Synthesis Conditions ◽  
Lead And Zinc ◽  
Nitrate Tetrahydrate

Two types of nanohydroxyapatite samples have been obtained by wet chemical precipitation synthesis, involving calcium nitrate tetrahydrate and diammonium hydrogen phosphate as precursors in different conditions. Powders obtained were characterized by X-ray diffraction (XRD) and FTIR spectroscopy. The equilibrium isotherm models related with lead and zinc ions removal from synthetic aqueous solutions have been also investigated. According to this research study, it has been found that the nanohydroxyapatite samples show good heavy metals adsorption capacity, and selectivity for lead ions. It was also observed a slow decreasing of sorption capacity of heavy metal ions from binary solutions compared to that registered from single heavy metal ion solutions.

Preparation and Characterization of Hydroxyapatite Whiskers

2013 ◽  
Vol 690-693 ◽  
pp. 404-408
Author(s):  
Ming Hua Huang ◽  
Qing Hua Chen ◽  
Yong Shun Cui ◽  
Wei Bo Zhu
Keyword(s):  
Raw Materials ◽  
Calcium Nitrate ◽  
Precipitation Method ◽  
Calcium Nitrate Tetrahydrate ◽  
Reaction Products ◽  
Ratio Distribution ◽  
Homogeneous Precipitation Method ◽  
Nitrate Tetrahydrate ◽  
Diammonium Hydrogen

The HAP whiskers were prepared by hydrothermal homogeneous precipitation method at the constant temperature. Diammonium hydrogen phosphate, calcium nitrate tetrahydrate, urea and nitric acid were used as the main raw materials. Sorbitol was selected as the template agent and the hydroxyapatite whiskers seeds were served as the inducers. SEM, TEM, XRD and EDS were applied in characterization. The results show that the reaction products are the HAP whiskers with high crystallinity, smooth appearance and no agglomeration; the obtained HAP whiskers are monocrystal and the length-diameter ratio distribution of the HAP whiskers is concentrated at about 30.

Temperature Measurement of Single Levitated Microparticles Using Stokes/Anti-Stokes Raman Intensity Ratios

1994 ◽  
Vol 48 (12) ◽  
pp. 1498-1505 ◽  
Author(s):  
Scot D. Rassat ◽  
E. James Davis
Keyword(s):  
Temperature Measurement ◽  
Calcium Nitrate ◽  
Composition Analysis ◽  
Calcium Nitrate Tetrahydrate ◽  
Electrodynamic Balance ◽  
Beam Expander ◽  
Nitrate Tetrahydrate ◽  
Intensity Ratios ◽  
Anti Stokes ◽  
Heating Beam

A method has been developed to determine the temperature of single microparticles levitated in an electrodynamic balance. Particle temperatures were ascertained from the measured intensities of the Stokes and anti-Stokes Raman spectra. Temperatures near ambient were obtained for titanium dioxide and calcium nitrate microparticles with the use of a Raman-based calibration of the optical system to correct for wavelength-dependent effects. Higher temperatures were also measured with the use of a carbon dioxide infrared laser to electromagnetically heat the particle. In an effort to minimize particle instabilities caused by the heating beam, the Gaussian intensity profile of the beam was modified with an axicon beam expander to produce a doughnut-like intensity distribution. The temperature measurement technique and quantitative Raman composition analysis were applied to study dehydration of a calcium nitrate tetrahydrate particle.

scholarly journals Synthesis of plate-like β-tricalcium phosphate nanoparticles and their efficiency in remineralization of incipient enamel caries

2019 ◽  
Vol 8 (4) ◽  
pp. 261-276
Author(s):  
Roghayyeh Marefat Seyedlar ◽  
Mohammadbagher Rezvani ◽  
Samira Barari ◽  
Mohammad Imani ◽  
Azizollah Nodehi ◽  
...  
Keyword(s):  
Tricalcium Phosphate ◽  
Calcium Nitrate ◽  
Negative Control ◽  
Second Phase ◽  
Calcium Nitrate Tetrahydrate ◽  
Enamel Caries ◽  
Nitrate Tetrahydrate ◽  
Addition Rate ◽  
Post Hoc ◽  
Caries Lesions

AbstractThe purpose of this study was to synthesize nano-sized β-tricalcium phosphate (nano-TCP) particles and determine its concentration-dependent properties on incipient enamel caries lesions. Nano-TCP was synthesized as a wet chemical through a method using low concentration of precursors and low addition rate of calcium nitrate tetrahydrate as a second phase. Morphology and phase composition of the particles were analyzed by SEM, XRD, and EDXA techniques. Incipient enamel lesions were created in human premolars with an acidic buffer. The teeth were then incubated in aqueous dispersions of nano-TCP as remineralization solutions. Sodium fluoride solution and deionized water were used as positive and negative control groups, respectively. The quality and thickness of the remineralized layer on enamel were investigated using SEM. The data were statistically analyzed by analysis of variance (ANOVA) and post hoc Tukey’s test. The synthesized nano-TCP mostly consisted of porous platelet-like crystals of 50–100 nm thickness and pore diameters of 100–300 nm. SEM observation showed that a homogenous layer was formed on the surface of the enamels remineralized in nano-TCP solutions. The thickness of the mineralized layer was dependent on the incubation time and nano-TCP concentration.

Sign in / Sign up

Export Citation Format

Share Document