scholarly journals Optical and X-ray-induced Luminescence Properties of Calcium Phosphate of Transparent Ceramic Form

2020 ◽  
Vol 32 (4) ◽  
pp. 1411
Author(s):  
Takumi Kato ◽  
Daisuke Nakauchi ◽  
Noriaki Kawaguchi ◽  
Takayuki Yanagida
Keyword(s):  
Calcium Phosphate ◽  
Transparent Ceramic ◽  
Luminescence Properties ◽  
X Ray

scholarly journals Microwave-Assisted Fabrication of Mesoporous Silica-Calcium Phosphate Composites for Dental Application

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 53
Author(s):  
Adrian Szewczyk ◽  
Adrianna Skwira ◽  
Marta Ginter ◽  
Donata Tajer ◽  
Magdalena Prokopowicz
Keyword(s):  
Calcium Phosphate ◽  
Mesoporous Silica ◽  
Octacalcium Phosphate ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Coating Solution ◽  
X Ray ◽  
Microwave Assisted ◽  
Calcium Orthophosphates ◽  
Different Types

Herein, the microwave-assisted wet precipitation method was used to obtain materials consisting of mesoporous silica (SBA-15) and calcium orthophosphates (CaP). Composites were prepared through immersion of mesoporous silica in different calcification coating solutions and then exposed to microwave radiation. The composites were characterized in terms of molecular structure, crystallinity, morphology, chemical composition, and mineralization potential by Fourier-transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), and scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (SEM-EDX). The application of microwave irradiation resulted in the formation of different types of calcium orthophosphates such as calcium deficient hydroxyapatite (CDHA), octacalcium phosphate (OCP), and amorphous calcium phosphate (ACP) on the SBA-15 surface, depending on the type of coating solution. The composites for which the progressive formation of hydroxyapatite during incubation in simulated body fluid was observed were further used in the production of final pharmaceutical forms: membranes, granules, and pellets. All of the obtained pharmaceutical forms preserved mineralization properties.

The Relative Merits of Oxides of Hafnium, Cerium and Thorium as Surrogates for Plutonium Oxide in Calcium Phosphate Ceramics

2009 ◽  
Vol 1193 ◽  
Author(s):  
B. L. Metcalfe ◽  
S. K. Fong ◽  
L. A. Gerrard ◽  
I. W. Donald ◽  
E. S. Welch ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Calcination Temperature ◽  
Cerium Oxide ◽  
Absorption Spectroscopy ◽  
Hafnium Oxide ◽  
Intermediate Level ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Absorption ◽  
Additional Phase

AbstractThe choice of surrogate for plutonium oxide for use during the initial stages of research into the immobilization of intermediate level pyrochemical wastes containing plutonium andamericium oxides in a calcium phosphate host has been investigated by powder X-ray diffraction and X-ray absorption spectroscopy. Two non-radioactive surrogates, hafnium oxide and cerium oxide, together with radioactive thorium oxide were compared. Similarities in behaviour were observed for all three surrogates when calcined at the lowest temperature, 750°C but differences became more pronounced as the calcination temperature was increased to 950°C. Although some reaction occurred between all the surrogates and the host to form a substituted whitlockite phase, increasing the temperature led to a significant increase in the cerium reaction and the formation of an additional phase, monazite. Additionally it was observed that the cerium became increasingly trivalent at higher temperatures.

X-ray induced luminescence properties of (Y,Eu)AlO 3 single crystals

2017 ◽  
Vol 64 ◽  
pp. 282-287 ◽  
Author(s):  
Tomoaki Kuro ◽  
Daisuke Nakauchi ◽  
Go Okada ◽  
Noriaki Kawaguchi ◽  
Takayuki Yanagida
Keyword(s):  
Single Crystals ◽  
Luminescence Properties ◽  
X Ray

Fabrication and evaluation of calcium phosphate cement scaffold with controlled internal channel architecture and complex shape

2007 ◽  
Vol 221 (8) ◽  
pp. 951-958 ◽  
Author(s):  
X Li ◽  
D Li ◽  
B Lu ◽  
L Wang ◽  
Z Wang
Keyword(s):  
Tissue Engineering ◽  
Calcium Phosphate ◽  
Calcium Phosphate Cement ◽  
Complex Shape ◽  
X Ray Diffraction ◽  
X Ray ◽  
Precise Control ◽  
Internal Channel ◽  
Channel Architecture

The ability to have precise control over internal channel architecture, porosity, and external shape is essential for tissue engineering. The feasibility of using indirect stereo-lithography (SL) to produce scaffolds from calcium phosphate cement materials for bone tissue engineering has been investigated. The internal channel architecture of the scaffolds was created by removal of the negative resin moulds made with SL. Scanning electron microscopy (SEM) showed highly open, well-interconnected channel architecture. The X-ray diffraction examination revealed that the hydroxyapatite phase formed at room temperature in the cement was basically stable up to 850 °C. There was no phase decomposition of hydroxyapatite, although the crystallinity and grain size were different. The ability of resulting structure to support osteoblastic cells culture was tested in vitro. Cells were evenly distributed on exterior surfaces and grew into the internal channels of scaffolds. To exploit the ability of this technique, anatomically shaped femoral supracondylar scaffolds with 300-800 μm interconnected channels were produced and characterized.

Synthesis of Alpha-Tricalcium Phosphate by Wet Reaction and Evaluation of Mechanical Properties

2012 ◽  
Vol 727-728 ◽  
pp. 1164-1169 ◽  
Author(s):  
Mônica Beatriz Thürmer ◽  
Rafaela Silveira Vieira ◽  
Juliana Machado Fernandes ◽  
Wilbur Trajano Guerin Coelho ◽  
Luis Alberto Santos
Keyword(s):  
Mechanical Properties ◽  
Calcium Phosphate ◽  
Tricalcium Phosphate ◽  
Calcium Nitrate ◽  
Chemical Precipitation ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Calcium Phosphate Cements

Calcium phosphate cements have bioactivity and osteoconductivity and can be molded and replace portions of bone tissue. The aim of this work was to study the obtainment of α-tricalcium phosphate, the main phase of calcium phosphate cement, by wet reaction from calcium nitrate and phosphoric acid. There are no reports about α-tricalcium phosphate obtained by this method. Two routes of chemical precipitation were evaluated and the use of two calcinations temperatures to obtain the phase of cement. The influence of calcination temperature on the mechanical properties of cement was evaluated. Cement samples were characterized by particle size analysis, X-ray diffraction, mechanical strength and scanning electron microscopy. The results demonstrate the strong influence of synthesis route on the crystalline phases of cement and the influence of concentration of reactants on the product of the reaction, as well as, on the mechanical properties of cement.

scholarly journals Lactoferrin/Calcium Phosphate-Modified Porous Ti by Biomimetic Mineralization: Effective Infection Prevention and Excellent Osteoinduction

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 992
Author(s):  
Song Chen ◽  
Yuanli He ◽  
Linna Zhong ◽  
Wenjia Xie ◽  
Yiyuan Xue ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Photoelectron Spectroscopy ◽  
Antibacterial Properties ◽  
Biomimetic Mineralization ◽  
Matrix Mineralization ◽  
X Ray ◽  
Porous Ti ◽  
Potential Applications ◽  
Modification Of Titanium

The surface modification of titanium (Ti) can enhance the osseointegration and antibacterial properties of implants. In this study, we modified porous Ti discs with calcium phosphate (CaP) and different concentrations of Lactoferrin (LF) by biomimetic mineralization and examined their antibacterial effects and osteogenic bioactivity. Firstly, scanning electron microscopy (SEM), the fluorescent tracing method, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and the releasing kinetics of LF were utilized to characterize the modified Ti surface. Then, the antibacterial properties against S. sanguis and S. aureus were investigated. Finally, in vitro cytological examination was performed, including evaluations of cell adhesion, cell differentiation, extracellular matrix mineralization, and cytotoxicity. The results showed that the porous Ti discs were successfully modified with CaP and LF, and that the LF-M group (200 μg/mL LF in simulated body fluid) could mildly release LF under control. Further, the LF-M group could effectively inhibit the adhesion and proliferation of S. sanguis and S. aureus and enhance the osteogenic differentiation in vitro with a good biocompatibility. Consequently, LF-M-modified Ti may have potential applications in the field of dental implants to promote osseointegration and prevent the occurrence of peri-implantitis.

Luminescence Properties of Pr3+ Doped in Ba3La(PO4)3 with Vacuum Ultraviolet and X-ray Excitation

2021 ◽  
Vol 42 (11) ◽  
pp. 1756-1762
Author(s):  
Qiu-feng SHI ◽  
◽  
Lei WANG ◽  
Hai-jie GUO ◽  
Ping HUANG ◽  
...  
Keyword(s):  
Vacuum Ultraviolet ◽  
Luminescence Properties ◽  
X Ray

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.

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