Calcium Phosphate Dental Cements

1989 ◽  
Vol 179 ◽  
Author(s):  
Like Xie ◽  
E. A. Monroe
Keyword(s):  
Single Phase ◽  
Setting Time ◽  
Solution Concentration ◽  
Tetracalcium Phosphate ◽  
High Ph ◽  
Mixture Phase ◽  
Good Biocompatibility ◽  
Basic Solutions ◽  
Short Time ◽  
Hydrolysis Of

AbstractCement systems composed of tetracalcium phosphate powder or powder mixtures of tetracalcium phosphate and brushite were investigated. The liquid components for making the cements include aqueous solutions of H3PO4, Ca(OH)2, or Na2SiO3. For the tetracalcium phosphate cement, strong acidic or basic solutions must be used in order to achieve a short setting time.Our results show that the tetracalcium phosphate and brushite cement can set in a short time under suitable conditions. Humidity, particle size, and pH of liquid have a strong influence on cement setting. Solutions of Ca(OH)2 or Na2SiO3 can be used for making high pH cements and a solution of H3PO4 for a low pH setting cement. To reduce the setting time of cement, the key is to control the hydrolysis of tetracalcium phosphate. The results of hydrolysis indicate that, at 37°C, the single-phase tetracalcium phosphate can only be converted to hydroxyapatite when hydrolyzed in solutions with an H3PO4 solution concentration of ∼5% or with a high pH solution.Both the single-phase tetracalcium phosphate cement and the mixture phase cement have good biocompatibility. Appropriate concentrations of the solutions of Na2SiO 3,Ca(OH)2, or H3P04 can be used in the cements from the perspective of both biocompatibility and cement properties.

scholarly journals Isothermal and non-isothermal kinetics of hydrolysis of 1-[2-(2- pentyloxyphenylcarbamoyloxy)-(2-methoxymethyl)-ethyl]- perhydroazepinium chloride (BK 129)

2013 ◽  
Vol 60 (2) ◽  
pp. 43-48
Author(s):  
Stankovičová M. ◽  
Bezáková Ž. ◽  
Beňo P. ◽  
Húšťavová P.
Keyword(s):  
Biological Activity ◽  
Alkaline Hydrolysis ◽  
Functional Group ◽  
Isothermal Kinetics ◽  
Basic Part ◽  
Buffer Solutions ◽  
Kinetics Of Hydrolysis ◽  
Short Time ◽  
Kinetics Of ◽  
Hydrolysis Of

Abstract The substance BK 129 - 1-[2-(2-pentyloxyphenylcarbamoyloxy)-(2-methoxymethyl)-ethyl]-perhydroazepinium chloride was prepared in terms of influence of the connecting chain between the carbamate functional group and the basic part of molecule on biological activity. Such a structural feature is important with regard to its stability. In this work we determined the rate constants of alkaline hydrolysis of this compound at increased temperature under isothermal and non-isothermal conditions. The hydrolysis was also performed in buffer solutions with the purpose of evaluating its stability. Non-isothermal tests of stability enable to reduce the number of analyses. The necessary data for stability of compound are in this way achieved in a short time.

scholarly journals Effect of CaO on Phase Composition and Properties of Aluminates for Barium Tungsten Cathode

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1380 ◽  
Author(s):  
Jinglin Li ◽  
Jianjun Wei ◽  
Yongbao Feng ◽  
Xiaoyun Li
Keyword(s):  
Single Phase ◽  
Emission Current Density ◽  
Environmental Stability ◽  
Precipitation Method ◽  
Pulse Emission ◽  
Molar Amount ◽  
Mixture Phase ◽  
Before And After ◽  
Method Effects ◽  
Co Precipitation

6BaO·xCaO·2Al2O3 (x = 0.8, 1.2, 1.6, 2, and 2.2) aluminates were synthesized via a liquid phase co-precipitation method. Effects of the molar amount of CaO on the phase of aluminates before and after melting and their hygroscopic phase, melting properties, environmental stability, evaporation, and emission properties were systematically studied. The results show that with the increase of the molar amount of CaO, the aluminates change from a mixture phase to a single phase of Ba3CaAl2O7, and the diffraction peak shifts to a higher angle. The melted phase of the aluminates changed from a single phase to a mixed phase of Ba5CaAl4O12 and Ba3CaAl2O7. Meanwhile, the comprehensive properties of the aluminates are improved. The weight gain of 6BaO·2CaO·2Al2O3 aluminates is only 10.88% after exposure to air for 48 h; the pulse emission current density of barium tungsten cathodes impregnated with 6BaO·2CaO·2Al2O3 aluminates in the porous tungsten matrix can reach 28.60 A/cm2 at 1050 °C, and the evaporation rate is 2.52 × 10−10 g/(cm2·s).

Consolidation of Aluminium Oxynitride Powders Using Hydrolysis of Aluminium Nitride

2014 ◽  
Vol 602-603 ◽  
pp. 170-174 ◽  
Author(s):  
Mirosław M. Bućko ◽  
Jakub Domagała ◽  
Radosław Lach
Keyword(s):  
Thermal Shock Resistance ◽  
Single Phase ◽  
Erosion Resistance ◽  
Aluminum Oxynitride ◽  
Spinel Type ◽  
Shock Resistance ◽  
Aluminium Oxynitride ◽  
Hydrolysis Of ◽  
High Thermal Shock Resistance ◽  
Shs Method

One of the materials with high potential for application as a refractory material is aluminum oxynitride with spinel-type structure, γ-alon. Alon materials, single-phase or composites, are characterized by good mechanical properties, high thermal shock resistance and a high corrosion and erosion resistance. Another advantage is possibility of usage of SHS method for producing of relatively good sinterable powders of γ-alon, however, are characterized by poor compressibility. This paper describes a method of compaction of SHS-derived γ-alon powder using the hydrolysis reaction of aluminum nitride, which is one of the products of SHS synthesis. The green bodies made from the powder with addition of 10 mas.% of water after two weeks of storage reach a strength level up to 30 MPa and an open porosity of less than 30%. Pressureless sintering of the such compacts allows to achieve 95% of theoretical density at 1700°C in less than one minute.

scholarly journals Exploring the Use of a Modified High-Temperature, Short-Time Continuous Heat Exchanger with Extended Holding Time (HTST-EHT) for Thermal Inactivation of Trypsin Following Selective Enzymatic Hydrolysis of the β-Lactoglobulin Fraction in Whey Protein Isolate

Foods ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 367 ◽  
Author(s):  
Laura Sáez ◽  
Eoin Murphy ◽  
Richard J. FitzGerald ◽  
Phil Kelly
Keyword(s):  
High Temperature ◽  
Heat Exchanger ◽  
Whey Protein ◽  
Protein Isolate ◽  
Holding Time ◽  
High Temperature Short Time ◽  
Incubation Periods ◽  
Short Time ◽  
Β Lactoglobulin ◽  
Hydrolysis Of

Tryptic hydrolysis of whey protein isolate under specific incubation conditions including a relatively high enzyme:substrate (E:S) ratio of 1:10 is known to preferentially hydrolyse β-lactoglobulin (β-LG), while retaining the other major whey protein fraction, i.e., α-lactalbumin (α-LA) mainly intact. An objective of the present work was to explore the effects of reducing E:S (1:10, 1:30, 1:50, 1:100) on the selective hydrolysis of β-LG by trypsin at pH 8.5 and 25 °C in a 5% (w/v) WPI solution during incubation periods ranging from 1 to 7 h. In addition, the use of a pilot-scale continuous high-temperature, short-time (HTST) heat exchanger with an extended holding time (EHT) of 5 min as a means of inactivating trypsin to terminate hydrolysis was compared with laboratory-based acidification to <pH 3 by the addition of HCl, and batch sample heating in a water bath at 85 °C. An E:S of 1:10 resulted in 100% and 30% of β-LG and α-LA hydrolysis, respectively, after 3 h, while an E:S reduction to 1:30 and 1:50 led >90% β-LG hydrolysis after respective incubation periods of 4 and 6 h, with <5% hydrolysis of α-LA in the case of 1:50. Continuous HTST-EHT treatment was shown to be an effective inactivation process allowing for the maintenance of substrate selectivity. However, HTST-EHT heating resulted in protein aggregation, which negatively impacts the downstream recovery of intact α-LA. An optimum E:S was determined to be 1:50, with an incubation time ranging from 3 h to 7 h leading to 90% β-LG hydrolysis and minimal degradation of α-LA. Alternative batch heating by means of a water bath to inactivate trypsin caused considerable digestion of α-LA, while acidification to <pH 3.0 restricted subsequent functional applications of the protein.

scholarly journals Polymeric-Calcium Phosphate Cement Composites-Material Properties:In VitroandIn VivoInvestigations

2010 ◽  
Vol 2010 ◽  
pp. 1-14 ◽  
Author(s):  
Rania M. Khashaba ◽  
Mervet M. Moussa ◽  
Donald J. Mettenburg ◽  
Frederick A. Rueggeberg ◽  
Norman B. Chutkan ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Calcium Phosphate Cement ◽  
Setting Time ◽  
Cement Composites ◽  
Tetracalcium Phosphate ◽  
Methyl Vinyl Ether ◽  
Orthopedic Applications ◽  
Hydroxyapatite Cement

New polymeric calcium phosphate cement composites (CPCs) were developed. Cement powder consisting of 60 wt% tetracalcium phosphate, 30 wt% dicalcium phosphate dihydrate, and 10 wt% tricalcium phosphate was combined with either 35% w/w poly methyl vinyl ether maleic acid or polyacrylic acid to obtain CPC-1 and CPC-2. The setting time and compressive and diametral tensile strength of the CPCs were evaluated and compared with that of a commercial hydroxyapatite cement.In vitrocytotoxicity andin vivobiocompatibility of the two CPCs and hydroxyapatite cement were assessed. The setting time of the cements was 5–15 min. CPC-1 and CPC-2 showed significantly higher compressive and diametral strength values compared to hydroxyapatite cement. CPC-1 and CPC-2 were equivalent to Teflon controls after 1 week. CPC-1, CPC-2, and hydroxyapatite cement elicited a moderate to intense inflammatory reaction at 7 days which decreased over time. CPC-1 and CPC-2 show promise for orthopedic applications.

Preparation Of Single-Phase Knbo3, Using Bimetallc Alkoxides

1990 ◽  
Vol 180 ◽  
Author(s):  
Mostafa M. Amini ◽  
Michael D. Sacks
Keyword(s):  
Thin Films ◽  
Single Phase ◽  
Methanol Solution ◽  
Multiphase Material ◽  
Niobium Ethoxide ◽  
Bimetallic Alkoxides ◽  
Hydrolysis Of ◽  
Propanol Solution

ABSTRACTSingle-phase KNbO3 was prepared using bimetallic alkoxides. Potassium-niobium ethoxide, KNb(OC2H5)6, and potassium-niobium propoxide, KNb(OC3H7)6, were synthesized and subsequently hydrolyzed using several water concentrations. Potassium-deficient particles were rapidly precipitated when higher water concentrations were used and this resulted in the formation of a multiphase material after calcination. In contrast, single-phase KNbO3 powders could be prepared by two methods: (1) hydrolysis of KNb(OC3H7)6/propanol solutions using 1 mole water (per mole of propoxide) added as a water/propanol solution and (2) hydrolysis of KNb(OC2H5)6,/ethanol solutions using 1 mole of water (per mole of ethoxide) added as a water/methanol solution. The latter method was also used to form thin films of KNbO3.

Sign in / Sign up

Export Citation Format

Share Document