scholarly journals Hibrid biomaterials based on hydroxyapatite and blood components

2019 ◽  
Vol 55 (3) ◽  
pp. 299-308
Author(s):  
V. K. Krut’ko ◽  
R. A. Vlasov ◽  
O. N. Musskaya ◽  
I. E. Glazov ◽  
A. I. Kulak
Keyword(s):  
Single Phase ◽  
Fluid Model ◽  
Chemical Precipitation ◽  
Simultaneous Increase ◽  
Blood Components ◽  
Biomimetic Apatite ◽  
Hydroxyapatite Gel ◽  
Hybrid Biomaterials ◽  
Partial Resorption ◽  
Citrate Plasma

Hybrid biomaterials based on amorphous hydroxyapatite and blood components (fibrin, citrate plasma) were developed by chemical precipitation of hydroxyapatite in a biopolymer matrix (pH 11; Ca/P ratio 1.67) and by mixing 6–14 wt.% of hydroxyapatite gel (pH 7.0–7.2) with bipolymers. Chemically precipitated hydroxyapatite in biopolymer matrices is single phase or contains ticalcium phosphate impurity up to 30 %, mainly α-modification in fibrin matrix and β-modification in citrate plasma. The interaction of hydroxyapatite gel into the fibrin leads to significant amorphization of hydroxyapatite and an increase in its bioresorbability. Holding the composites with hydroxyapatite obtained by chemical precipitation in the Simulated Body Fluid model solution for 75 days leads to their partial resorption and simultaneous increase of biomimetic apatite, with its greater weight gain on composites with a fibrin. Hybrid biomaterials based on a fibrin obtained from the patient’s blood and hydroxyapatite gel showed positive result during implantation, allowing to form an adequate configuration of the defect, expanding the possibilities of ENT surgery.

scholarly journals SYNTHESIS AND INVESTIGATION OF BIOMIMETIC HYDROXYAPATITES DOPED BY SILICATE AND CARBONATE ANIONS IN THE PRESENCE OF CITRATE IONS

2020 ◽  
pp. 106-113 ◽  
Author(s):  
M. Troubitsin ◽  
Viet Hung Hoang ◽  
L. Furda
Keyword(s):  
Single Phase ◽  
Maximum Yield ◽  
Physiological Saline ◽  
Average Crystallite Size ◽  
Chemical Precipitation ◽  
Degree Of Crystallinity ◽  
Regeneration Of Bone Tissue ◽  
Biomimetic Hydroxyapatite ◽  
Regeneration Of Bone ◽  
Citrate Ions

In the present work, biomimetic hydroxyapatite (BHAP) doped with silicate and carbonate anions in the presence of citrate ions are synthesized by chemical precipitation from aqueous solutions. According to the results of X-ray phase analysis (XRD), all the obtained materials are single-phase. Scanning electron microscopy (SEM) demonstrates that BHAP powders are a collection of agglomerated particles with similar morphology. Dynamic light scattering confirms that the synthesized BHAPs consist of agglomerates 1–4μm in size. For all samples, with an increase in the number of introduced citrate ions, decreases in the average crystallite size and degree of crystallinity are observed. With an increase in the concentration of citrate ions, the content of agglomerate fractions of 1–2μm in size increases from 70.16 to 75.43%. The solubility of hydroxyapatite samples in physiological saline (ω(NaCl) = 0.9%) at temperatures of 22°C and 37°C is studied. It is revealed that for all synthesized BHAPs, the amount of released Ca2+ ions into the liquid phase increases. The maximum yield of Ca2+ ions in physiological saline is recorded in BHAP with the highest content of citrate ions. The obtained results allow to consider the synthesized BHAP as a promising medical biomaterial for the regeneration of bone tissue.

Rheological Properties of Hydroxyapatite Synthesized Clamshell Mix with Palm Stearin Binder System

2014 ◽  
Vol 911 ◽  
pp. 366-370 ◽  
Author(s):  
Istikamah Subuki ◽  
Ali Nurul Huda ◽  
Muhammad Hussain Ismail
Keyword(s):  
Single Phase ◽  
Volume Fraction ◽  
Flow Behavior ◽  
Palm Stearin ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Binder System ◽  
Shear Sensitivity ◽  
Rheological Test ◽  
Test Result

This study investigated the flow behavior of feedstock containing hydroxyapatite (HAp) powder with palm stearin (PS) based binder system. The HAp was synthesized via chemical precipitation method with the use of waste of clamshells. The result showed that single phase synthesized HAp was successfully formed at annealing temperature and pH solution of 850°C and 6.5, respectively. The synthesized HAp with a volume fraction of 65% was then mixed with PS and and Polyethylene binder at 160°C to prepare a feedstock. From the rheological test result, it was found that the feedstock exhibited a pseudoplastic behavior with low values of shear sensitivity in comparison with commercial HAp.

scholarly journals Nanomedicine: Interaction of biomimetic apatite colloidal nanoparticles with human blood components

2016 ◽  
Vol 145 ◽  
pp. 87-94 ◽  
Author(s):  
Maëla Choimet ◽  
Kim Hyoung-Mi ◽  
Oh Jae-Min ◽  
Audrey Tourrette ◽  
Christophe Drouet
Keyword(s):  
Human Blood ◽  
Colloidal Nanoparticles ◽  
Blood Components ◽  
Biomimetic Apatite

scholarly journals Two-Phase Flow Simulations Using 1D Centerline-Based C- and U-Shaped Pipe Meshes

2021 ◽  
Vol 11 (5) ◽  
pp. 2020
Author(s):  
Thinh Quy Duc Pham ◽  
Jichan Jeon ◽  
Daeseong Jo ◽  
Sanghun Choi
Keyword(s):  
Mesh Generation ◽  
Single Phase ◽  
Two Phase Flow ◽  
Fluid Model ◽  
Dynamic Pressure ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Two Phase ◽  
Two Fluid Model ◽  
Two Fluid

This study aims to investigate the pressure changes, bubble dynamics, and flow physics inside the U- and C-shaped pipes with four different gravitational directions. The simulation is performed using a 1D centerline-based mesh generation technique along with a two-fluid model in the open-source software, OpenFOAM v.6. The continuity and momentum equations of the two-fluid model are discretized using the pressure-implicit method for the pressure-linked equation algorithm. The static and hydrostatic pressures in the two-phase flow were consistent with those of single-phase flow. The dynamic pressure in the two-phase flow was strongly influenced by the effect of the buoyancy force. In particular, if the direction of buoyancy force is the same as the flow direction, the dynamic pressure of the air phase increases, and that of the water phase decreases to satisfy the law of conservation of mass. Dean flows are observed on the transverse plane of the curve regions in both C-shaped and U-shaped pipes. The turbulent kinetic energy is stronger in a two-phase flow than in a single-phase flow. Using the 1D centerline-based mesh generation technique, we demonstrate the changes in pressure and the turbulent kinetic energy of the single- and two-phase flows, which could be observed in curve pipes.

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.

Dielectric and Conductivity Studies of Sr[(Mg0.32Co0.02) Nb0.66]O3 Thin Film

2009 ◽  
Vol 155 ◽  
pp. 145-149
Author(s):  
P.K. Mehta ◽  
Bhagwati Bishnoi ◽  
Ravi Kumar ◽  
R.J. Choudhary ◽  
D.M. Phase
Keyword(s):  
Thin Film ◽  
Activation Energy ◽  
Temperature Region ◽  
Single Phase ◽  
Dissipation Factor ◽  
Simultaneous Increase ◽  
X Ray Diffraction ◽  
Alternative Technologies ◽  
Shallow Traps ◽  
Single Phase Formation

Study of Sr[(Mg0.32Co0.02) Nb0.66]O3 [SMCN] thin films prepared by Pulsed Laser Deposition Technique (PLD) were carried out in the temperature range of 150 to 450K and frequency range of 100KHz to 1.1MHz. X-ray diffraction of the thin film shows single phase formation with monoclinic symmetry. The dielectric properties show enhanced ε' values compared to bulk suggesting promising applications in alternative technologies. Due to simultaneous increase in dissipation factor with temperature the net ac conductivity is found to be decreasing. Technologically important two step activation energy is observed in the film. This property can be used in switching devices. In low temperature region the activation energy corresponds to shallow traps while the migration of oxygen vacancies contributes in high temperature region.

scholarly journals 3D simulation of gas-laden liquid flows in centrifugal pumps and the assessment of two-fluid CFD methods

2020 ◽  
Vol 3 (3) ◽  
pp. 186-207 ◽  
Author(s):  
Markus Hundshagen ◽  
Michael Mansour ◽  
Dominique Thévenin ◽  
Romuald Skoda
Keyword(s):  
Gas Phase ◽  
Spatial Resolution ◽  
Single Phase ◽  
High Spatial Resolution ◽  
Fluid Model ◽  
Phase Flow ◽  
Two Phase ◽  
Two Fluid Model ◽  
Liquid Flows ◽  
Two Fluid

Abstract An assessment of a two-fluid model assuming a continuous liquid and a dispersed gas phase for 3D computational fluid dynamics (CFD) simulations of gas/liquid flow in a centrifugal research pump is performed. A monodisperse two-fluid model, in conjunction with a statistical eddy-viscosity turbulence model, is utilized. By a comprehensive measurement database, a thorough assessment of model inaccuracies is enabled. The results on a horizontal diffuser flow reveal that the turbulence model is one main limitation of simulation accuracy for gas/liquid flows. Regarding pump flows, distinctions of single-phase and two-phase flow in a closed and semi-open impeller are figured out. Even single-phase flow simulations reveal challenging requirements on a high spatial resolution, e.g., of the rounded blade trailing edge and the tip clearance gap flow. In two-phase pump operation, gas accumulations lead to coherent gas pockets that are predicted partly at wrong locations within the blade channel. At best, a qualitative prediction of gas accumulations and the head drop towards increasing inlet gas volume fractions (IGVF) can be obtained. One main limitation of two-fluid methods for pump flow is figured out in terms of the violation of the dilute, disperse phase assumption due to locally high disperse phase loading within coherent gas accumulations. In these circumstances, bubble population models do not appear beneficial compared to a monodisperse bubble distribution. Volume-of-Fluid (VOF) methods may be utilized to capture the phase interface at large accumulated gas cavities, requiring a high spatial resolution. Thus, a hybrid model, i.e., a dispersed phase two-fluid model including polydispersity for flow regions with a dilute gas phase, should be combined with an interphase capturing model, e.g., in terms of VOF. This hybrid model, together with scale-resolving turbulence models, seems to be indispensable for a quantitative two-phase pump performance prediction.

Role of synthesis variables on controlled nucleation and growth of hexagonal molybdenum oxide nanocrystals: investigation on thermal and optical properties

CrystEngComm ◽  
2014 ◽  
Vol 16 (27) ◽  
pp. 6175-6186 ◽  
Author(s):  
A. Chithambararaj ◽  
A. Chandra Bose
Keyword(s):  
Optical Properties ◽  
Molybdenum Oxide ◽  
Single Phase ◽  
Chemical Precipitation ◽  
Nucleation And Growth ◽  
Controlled Synthesis ◽  
Controlled Nucleation

Solution based chemical precipitation route has been utilized for the controlled synthesis of novel and single phase 3Dhierarchical flower-like microspheres of hexagonal molybdenum oxide nanocrystals.

scholarly journals INFLUENCE OF THE CRYSTAL-CHEMICAL STRUCTURE IN CALCIUM-PHOSPHATE NANOCOMPOSITE ON THE FORMATION OF ELECTROSURFACE AND ACID-BASIC PROPERTIES

2021 ◽  
Vol 6 (2) ◽  
pp. 89-99
Author(s):  
M. Troubitsin ◽  
Viet Hung Hoang ◽  
L. Furda
Keyword(s):  
Calcium Phosphate ◽  
Chemical Structure ◽  
Single Phase ◽  
Aqueous Suspension ◽  
Chemical Precipitation ◽  
Crystal Chemical ◽  
Active Centers ◽  
X Ray ◽  
Molar Ratios ◽  
Design Values

The single-phase modified nanostructured hydroxyapatites and biomimetic calcium-phosphate nanocomposite (BMHAP) doped by silicate and carbonate anions are synthesized by chemical precipitation in aqueous solutions. The chemical composition of the obtained samples is studied by energy dispersive X-ray spectroscopy using a scanning electron microscope. It is shown that the obtained molar ratios are close to the design values in all samples. The influence of different modifying ions in the crystal-chemical structure of hydroxyapatite (HAp) on the electrosurface properties of the synthesized products has been studied. Unmodified hydroxyapatite, silicate-substituted hydroxyapatite, and BMHAP particles are found to carry a negative charge in an aqueous suspension at pH = 7, while carbonate-substituted HAp particles had a positive charge. It is revealed that the introduction of silicate and carbonate anions into the HAp structure is accompanied by an increase in negative values of the zeta-potential from -1.05 to -4.29 mV. The change in the distribution of active centers on the surface of modified nanostructured hydroxyapatites is studied by the adsorption of acid-base indicators method with pKax in the range from -0.3 to +12.8. In contrast to stoichiometric hydroxyapatite, in BMHAP the neutral Bronsted centers prevails, and their concentration is 48.38 mmol-eq/g

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