Enhancement of glass-ceramic performance by TiO2 doping: In vitro cell viability,proliferation, and differentiation

A new TiO₂-containing bioactive glass and glass-ceramics based on 50SiO₂-(45-X)CaO-(XTiO₂)-5P₂O₅ system was designed using a sol–gel technique (where X = 5, 7.5 and 10 wt %). The roles of the crystallization behavior and physicochemical characteristics of the designed glass and glass-ceramics which were played in the introduction of TiO₂ substitutions were investigated. Moreover, cell proliferation and differentiation were evaluated against human osteosarcoma cells (Saos-2). The TiO₂/CaO replacements led to the formation of a stronger glass structure and thus increased thermal parameters and the chemical stabilization of the designed materials. The FTIR data confirmed the existence of Ti within the glass and glass-ceramics samples, and no remarkable effect on their chemical integrity was observed. The XRD patterns indicated that calcium-containing minerals, including Ca₂SiO₄,Ca₃(PO₄)₂, Ca(Ti,Si)O₅, CaTiSiO₅, and Ca₁₅(PO₄)₂·(SiO₄)₆ phases were developed as a role of structure/texture under the applied heat-treatment. The results of the cytotoxicity test proved that a safe sample dose is 12–50 μg/ml, at which cell viability is ≥ 85%. The cell differentiation determined by ALP test proved the superiority of glass-ceramics compared with their native glasses. Therefore, the obtained materials could be safely used as novel biocompatible materials for the regeneration of bone tissue.     

Long-term sustained-released in situ gels of a water-insoluble drug amphotericin B for mycotic arthritis intra-articular administration: preparation,in vitro and in vivo evaluation

Amphotericin B (AMB) was often used in intra-articular injection administration for fungal arthritis, because it could often bring a satisfactory therapeutic efficacy and a minimum systemic toxic side effect. However, because of the multiple operations and the frequent injections, the compliance of the patients was bad. Therefore, to develop a long-term sustained-released preparation of AMB for mycotic arthritis intra-articular administration is of great significance. The purpose of present study was to develop a long-term sustained-released in situ gel of a water-insoluble drug AMB for mycotic arthritis intra-articular administration. Based on the evaluations of the in vitro properties of the formulations, the formulation containing 10% (w/w) ethanol, 15% (w/w) PG, 0.75% (w/w) HA, 5% (w/w) purified soybean oil, 0.03% (w/w) α-tocopherol, 15% (w/w) water and 55% (w/w) glyceryl monooleate was selected as a suitable intra-articular injectable in situ gel drug delivery system for water-insoluble drug AMB. Furthermore, the results of the in vivo study on rabbits showed that the selected formulation was a safe and effective long-term sustained-released intra-articular injectable AMB preparation. Therefore, the presented in situ AMB gel could reduce the frequency of the administration in the AMB treatment of fungal arthritis, and then would get a good patient compliance.     

Numerical study of entropy generation in Darcy-Forchheimer (D-F) Bödewadt flow of CNTs

Three-dimensional Bödewadt flow (fluid rotates at a large enough distance from the stationary plate) of carbon nanomaterial is examined. Single walled and multi walled CNTs are dissolved in water and gasoline oil baseliquids. Darcy-Forchheimer porous medium is considered. Stationary disk is further stretched linearly in radial direction. Heat transfer effect is examined in presence of radiation and convection. Effect of viscous dissipation is accounted. Entropy generation rate is studied. By using adequate transformation (von Kármán relations), the flow field equations (PDEs) are transmitted into ODEs. Solutions to these ODEs are constructed via implementation of shooting method (bvp4c). In addition to Entropy generation rate, Bejan number, heat transfer rate (Nusselt number), skin friction and temperature of fluid are examined through involved physical parameters. Axial component of velocity intensifies with increment in nanoparticles volume fraction and ratio of stretching rate to angular velocity parameter while it decays with higher porosity parameter. Higher nanoparticles volume fraction and porosity parameter lead to decay in radial as well as tangential component of velocity. However it enhances with higher ratio of stretching rate to angular velocity parameter. Temperature of fluid directly varies with higher ratio of stretching rate to angular velocity parameter, radiation parameter, Eckert number, Biot number and nanoparticles volume fraction. Rate of Entropy generation is reduced with higher estimations of porosity parameter, nanoparticles volume fraction and radiation parameter. Skin friction coefficient decays with higher porosity parameter and ratio of stretching rate to angular velocity parameter. Intensification in porosity parameter, nanoparticles volume fraction and Biot number leads to higher Nusselt number. Prominent impact is shown by multiple-walled CNTs with gasoline oil basefluid than single-walled CNTs with water basefluid.     

Sol–gel synthesis of Nd-doped BiFeO3 multiferroic and its characterization

Neodymium doped bismuth ferrite (BiFeO₃, BFO) nanoparticles were successfully synthesized by a facile sol–gel route. The influence of annealing temperature, time, Bi content and solvent on the crystal structure of BFO was studied. Results indicated that the optimum processing condition of BFO products was 550–600 °C/1.5 h with excess 3–6% Bi and ethylene glycol as solvent. On the other hand, Nd³⁺ ion was introduced into the BFO system and the effect of Nd³⁺ concentration on the structure, magnetic and dielectric properties of BFO were investigated. It was found that the magnetization of BFO was enhanced significantly with Nd³⁺ substitution, being attributed to the suppression of the spiral cycloidal magnetic structure led by the crystal structure transition. Furthermore, with increasing Nd³⁺ content, the dielectric constant was found to decrease while the dielectric loss was enhanced, which was mainly due to the hoping conduction mechanism with the reduction of oxygen vacancies.     

Performance of surface ionic conduction single chamber fuel cell prepared by the sol gel method

The performance of surface ionic conduction single chamber fuel cell (SIC‐SCFC) prepared by the sol gel method was studied on electric characteristics due to the differences of the operating temperature and humidity, the electrode distance and electrolyte film depth, and multiple cells with the series and parallel connections. The SIC–SCFC was arranged the both anode of Pt and cathode of Au on the boehmite electrolyte. The open circuit voltage (OCV) of single cell achieved a maximum of 530mV in the dry gas mixtures of O₂/H₂=50% in room temperature operation, and but it became decrease as over 60%. The OCV was maintained the constant value between operating temperatures of 30°C to 80°C, and but it was decreased sharply at over 90°C because a humidity on the cell became lower as increasing operating temperature. Then, the cell property was improved to 120°C by adding to the humidity of 70% using a humidifier. The electrode distance and the electrolyte film depth of SIC‐SCFC found to be contributed to the reductions of the cell resistance and the surface roughness on the electrode, respectively. Moreover, the power property of SIC‐SCFC was significantly improved by cell stacks comprised of the series or parallel connection of a cell.     

SiC/SiC mini-composites with multilayer ZrSiO4 interphase: Room-temperature properties and toughening mechanism

SiC/SiC mini-composites reinforced with SiC fibers coated with different numbers of ZrSiO₄ sublayers prepared via a non-hydrolytic sol-gel process were fabricated. The tensile strength and work of fracture of the prepared SiC/SiC mini-composites were determined, and the relationship between their mechanical properties and fracture morphologies was discussed. The toughening mechanism and the variation tendency of their mechanical properties were further elaborated by analyzing the interfacial debonding morphologies of the SiC/SiC mini-composites with 1 and 4 layers of ZrSiO₄ interphase as well as the results of prior studies. A relatively rare phenomenon—the delamination of the multilayer ZrSiO₄ interphase in the SiC/SiC mini-composites but not on the SiC fibers—was observed, which clearly demonstrated the weak bonding between the ZrSiO₄ sublayers in the SiC/SiC mini-composites. The ZrSiO₄ sublayer delamination mechanism was then explained based on the high-magnification morphologies found in and beside the ZrSiO₄ interphase.     

Efficient dye-sensitized solar cells based on CNTs and Zr-doped TiO2 nanoparticles

The light scattering, harvesting and adsorption effects in dye-sensitized solar cells (DSSCs) are studied by preparation of coated carbon nanotubes (CNTs) with TiO₂ and Zr-doped TiO₂ nanoparticles in the forms of mono- and double-layer cells. X-ray diffraction (XRD) analysis reveals that the phase composition of Zr-doped TiO₂ electrode is a mixture of anatase and rutile phases with major rutile content, whereas it is the same mixture with major anatase content for coated CNTs with TiO₂. Furthermore, the average crystallite size of Zr-doped TiO₂ electrode is slightly decreased with Zr introduction. Field emission scanning electron microscope (FE-SEM) images show that the porosity of Zr-doped TiO₂ electrodes is higher than that of undoped electrode, enhancing dye adsorption. UV–visible spectroscopy analysis reveals that the absorption onset of Zr-doped TiO₂ electrodes is slightly shifted to longer wavelength (the red-shift) in comparison with that of undoped TiO₂ electrode. Moreover, the band gap energy of TiO₂ nanoparticles is decreased by Zr introduction, enhancing light absorption. It is found that electron injection of monolayer TiO₂ electrode is improved by introduction of 0.025 mol% Zr, resulted in enhancement of its power conversion efficiency (PCE) up to 6.81% compared with 6.17% for pure TiO₂ electrode. Moreover, electron transport and light scattering are enhanced by incorporation of 0.025 wt% coated CNTs with TiO₂ in the over-layer of double layer electrode. Therefore, double layer solar cell composed of 0.025 mol% Zr-doped TiO₂ nanoparticles as the under-layer and mixtures of these nanoparticles and 0.025 wt% coated CNTs with TiO₂ as the over-layer shows the highest PCE of 8.19%.