Improvement of the mechanical properties of hydroxyapatite (HA) can be achieved by the incorporation of metal. In addition, incorporation of strontium ion into HA crystal structures has been proved effective to enhance biochemical properties of bone implant. In this research, strontium-doped HA powder was developed via a sol-gel method to produce extraordinarily fine strontium-doped HA (Sr-doped HA) powder. XRD measurement had shown that the powder contained hydroxyapatite phase only for all doping concentration except for 2%, showing that Sr atoms have suppressed the appearance of beta-TCP as the secondary phase. Morphological evaluation by FESEM measurement shows that the particles of the Sr-doped HA agglomerates are globular in shape with an average size of 1-2 microm in diameter while the primary particles have a diameter of 30-150 nm in average.
An enhanced ferromagnetic property, visible light active TiO(2) photocatalyst was successfully synthesized by supporting strontium ferrite (SrFe(12)O(19)) onto TiO(2) doped with nitrogen (N) and compared with N-doped TiO(2). The synthesized catalysts were further characterized with X-ray diffraction (XRD), transmission electron microscope (TEM), energy dispersive X-ray spectroscopy (EDS), BET surface area analysis, vibrating sample magnetometer (VSM), X-ray photon spectroscopy (XPS) and visible light spectroscopy analysis for their respective properties. The XRD and EDS revealed the structural and inorganic composition of N-TiO(2) supported on SrFe(12)O(19). The supported N-TiO(2) exhibited a strong ferromagnetic property with tremendous stability against magnetic property losses. It also resulted in reduced band gap (2.8 eV) and better visible light absorption between 400 and 800 nm compared to N-doped TiO(2). The photocatalytic activity was investigated with a recalcitrant phenolic compound namely 2,4-dichlorophenol (2,4-DCP) as a model pollutant under direct bright and diffuse sunlight exposure. A complete degradation of 2,4-DCP was achieved with an initial concentration of 50mg/L for both photocatalysts in 180 min and 270 min respectively under bright sunlight. Similarly the diffuse sunlight study resulted in complete degradation for supported N-TiO(2) and >85% degradation N-TiO(2), respectively. Finally the supported photocatalyst was separated under permanent magnetic field with a mass recovery ≈ 98% for further reuse.
Diabetes mellitus is a chronic disease accompanied by a multitude of problems worldwide with subcutaneously administered insulin being the most common therapy currently. Controlledrelease insulin is assumed to be of high importance for long-term glycaemic control by reducing the number of daily injections. Long-acting insulin also mimics the basal insulin levels in normal individuals that may be lacking in diabetic patients. Nanoparticles of carbonate apatite as established for efficient intracellular transport of DNA and siRNA have the potential to be used for sustained release of insulin as responsive nano-carriers. The flexibility in the synthesis of the particles over a wide range of pHs with eventual adjustment of pH-dependent particle dissolution and the manageable variability of particle-integrity by incorporating selective ions into the apatite structure are the promising features that could help in the development of sustained release formulations for insulin. In particular strontium-incorporated carbonate apatite particles were formulated and compared with those of unsubstituted apatite in the context of insulin binding and subsequent release kinetics in DMEM, simulated buffer and finally human blood over a period of 20 hours. Clearly, the former demonstated to have a stronger electrostatic affinity towards the acidic insulin molecules and facilitate to some extent sustained release of insulin by preventing the initial burst effect at physiological pH in comparison with the latter. Thus, our findings suggest that optimization of the carbonate apatite particle composition and structure would serve to design an ideal insulin nano-carrier with a controlled release profile.
This is our initial response towards preparation of nano-inductors garnet for high operating frequencies strontium iron garnet (Sr3Fe5O12) denoted as SrIG and yttrium iron garnet (Y3Fe5O12) denoted as YIG. The garnet nano crystals were prepared by novel sol-gel technique. The phase and crystal structure of the prepared samples were identified by using X-ray diffraction analysis. SEM images were done to reveal the surface morphology of the samples. Raman spectra was taken for yttrium iron garnet (Y3Fe5O12). The magnetic properties of the samples namely initial permeability (micro), relative loss factor (RLF) and quality factor (Q-Factor) were done by using LCR meter. From the XRD profile, both of the Y3Fe5O12 and Sr3Fe5O12 samples showed single phase garnet and crystallization had completely occurred at 900 degrees C for the SrIG and 950 degrees C for the YIG samples. The YIG sample showed extremely low RLF value (0.0082) and high density 4.623 g/cm3. Interesting however is the high Q factor (20-60) shown by the Sr3Fe5O12 sample from 20-100 MHz. This high performance magnetic property is attributed to the homogenous and cubical-like microstructure. The YIG particles were used as magnetic feeder for EM transmitter. It was observed that YIG magnetic feeder with the EM transmitter gave 39% higher magnetic field than without YIG magnetic feeder.