Biphase CaO–P2O5 ceramic based on powder synthesized from calcium acetate and ammonium hydrophosphate

2013 ◽  
Vol 70 (1-2) ◽  
pp. 65-70 ◽  
Author(s):  
T. V. Safronova ◽  
V. I. Putlyaev ◽  
G. K. Kazakova ◽  
S. A. Korneichuk
Ceramics ◽  
2018 ◽  
Vol 1 (2) ◽  
pp. 375-392 ◽  
Author(s):  
Tatiana Safronova ◽  
Valery Putlayev ◽  
Yaroslav Filippov ◽  
Tatiana Shatalova ◽  
Evgeny Karpushkin ◽  
...  

Calcium phosphate powder was synthesized at room temperature from aqueous solutions of ammonium hydrophosphate and calcium acetate without pH adjusting at constant Ca/P molar ratio 1.5. Phase composition of the as-synthesized powder depended on the precursors concentration: At 2.0 M of calcium acetate in the starting solution, poorly crystallized hydroxyapatite was formed, 0.125 M solution of calcium acetate afforded brushite, and the powders synthesized from 0.25–1.0 M calcium acetate solutions were mixtures of the mentioned phases. Firing at 1100 °C led to complete elimination of the reaction by-products, yet the phase composition of the annealed compacted samples was the following: When 2.0 M solution of calcium acetate was used, the obtained ceramics consisted of β-Ca3(PO4)2, whereas at 0.125 to 1.0 M of calcium acetate, the ceramics was a mixture of β-Ca3(PO4)2 and β-Ca2P2O7. Synthesized calcium phosphate powders can be used as the powdered precursors for biocompatible bioresorbable composite ceramics production.


2021 ◽  
pp. 1-10
Author(s):  
Peter A. McCullough

<b><i>Background:</i></b> Cardiovascular disease (CVD) is a major cause of death in patients with chronic kidney disease (CKD) on dialysis. Mortality rates are still unacceptably high even though they have fallen in the past 2 decades. Hyperphosphatemia (elevated serum phosphate levels) is seen in almost all patients with advanced CKD and is by far the largest remaining modifiable contributor to CKD mortality. <b><i>Summary:</i></b> Phosphate retention drives multiple physiological mechanisms linked to increased risk of CVD. Fibroblast growth factor 23 and parathyroid hormone (PTH) levels, both of which have been suggested to have direct pathogenic CV effects, increase in response to phosphate retention. Phosphate, calcium, and PTH levels are linked in a progressively worsening cycle. Maladaptive upregulation of phosphate absorption is also likely to occur further exacerbating hyperphosphatemia. Even higher phosphate levels within the normal range may be a risk factor for vascular calcification and, thus, CV morbidity and mortality. A greater degree of phosphate control is important to reduce the risk of CV morbidity and mortality. Improved phosphate control and regular monitoring of phosphate levels are guideline-recommended, established clinical practices. There are several challenges with the current phosphate management approaches in patients with CKD on dialysis. Dietary restriction of phosphate and thrice-weekly dialysis alone are insufficient/unreliable to reduce phosphate to &#x3c;5.5 mg/dL. Even with the addition of phosphate binders, the only pharmacological treatment currently indicated for hyperphosphatemia, the majority of patients are unable to achieve and maintain phosphate levels &#x3c;5.5 mg/dL (or more normal levels) [PhosLo® gelcaps (calcium acetate): 667 mg (prescribing information), 2011, VELPHORO®: (Sucroferric oxyhydroxide) (prescribing information), 2013, FOSRENAL®: (Lanthanum carbonate) (prescribing information), 2016, AURYXIA®: (Ferric citrate) tablets (prescribing information), 2017, RENVELA®: (Sevelamer carbonate) (prescribing information), 2020, RealWorld dynamix. Dialysis US: Spherix Global Insights, 2019]. Phosphate binders do not target the primary pathway of phosphate absorption (paracellular), have limited binding capacity, and bind nonspecifically [PhosLo® gelcaps (calcium acetate): 667 mg (prescribing information). 2013, VELPHORO®: (Sucroferric oxyhydroxide) (prescribing information), 2013, FOSRENAL®: (Lanthanum carbonate) (prescribing information), 2016, AURYXIA®: (Ferric citrate) tablets (prescribing information), 2017, RENVELA®: (Sevelamer carbonate) (prescribing information) 2020]. <b><i>Key Messages:</i></b> Despite current phosphate management strategies, most patients on dialysis are unable to consistently achieve target phosphate levels, indicating a need for therapeutic innovations [RealWorld dynamix. Dialysis US: Spherix Global Insights, 2019]. Given a growing evidence base that the dominant mechanism of phosphate absorption is the intestinal paracellular pathway, new therapies are investigating ways to reduce phosphate levels by blocking absorption through the paracellular pathway.


1988 ◽  
Vol 3 (4) ◽  
pp. 426-428 ◽  
Author(s):  
TAKEO HATTORI ◽  
YASUHIKO IWADATE ◽  
TOMOYOSHI KATO

Fuel ◽  
1999 ◽  
Vol 78 (5) ◽  
pp. 583-592 ◽  
Author(s):  
J. Adánez ◽  
L.F. de Diego ◽  
F. Garcı́a-Labiano

2015 ◽  
Vol 1087 ◽  
pp. 116-120 ◽  
Author(s):  
Te Chuan Lee ◽  
Maizlinda Izwana Idris ◽  
Hasan Zuhudi Abdullah ◽  
Charles Christopher Sorrell

Anodic oxidation is a surface modification method which combines electric field driven metal and oxygen ion diffusion for formation of oxide layer on the anode surface. Anodised titanium has been widely use in biomedical applications especially in dental implant. This study aimed to investigate the effect of electrolyte concentration on titanium. Specifically, the titanium foil was anodised in mixture of β-glycerophosphate disodium salt pentahydrate (β-GP) and calcium acetate monohydrate (CA) with different concentration (0.02 M + 0.2 M and 0.04 M + 0.4 M), anodising time (10 min), applied voltage (150, 200, 250, 300 and 350 V) and current density (10 mA.cm-2) at room temperature. Surface oxide properties of anodised titanium were characterised by using glancing angle X-ray diffraction (GAXRD), field emission scanning electron microscope (FESEM), focused ion beam (FIB) milling and digital camera. With increasing electrolyte concentration, the oxide layer became more porous. The GAXRD results also showed that rutile formed at high applied voltage (≥300 V) when the higher concentration of electrolyte was used.


InterConf ◽  
2021 ◽  
pp. 970-978
Author(s):  
Z. Nizomov ◽  
M. Asozoda ◽  
A. Olimi ◽  
A. Karimzoda

The absorption of ultrasonic waves in the frequency range from 6 to 146 MHz in aqueous solutions of sodium acetate, sodium chloride and calcium has been studied. It was found that only in solutions of calcium cations and acetate anion present simultaneously, relaxation absorption of ultrasonic waves is observed. The experimental data obtained indicate that the observed relaxation absorption of ultrasound in the studied frequency range by an aqueous solution of calcium acetate is associated with the interaction of the acetate anion with the calcium cation in the solution.


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