Synthesis and characterization of pure and zinc doped calcium pyrophosphate dihydrate nanoparticles

Calcium phosphate based biomaterials are widely used in dentistry and as a bone substitutes in orthopedic applications. Calcium pyrophosphate (CPP) – a type of calcium phosphate and a shortest linear polyphosphate can also be used as a bone graft. Successive applications of theses materials depend on the degree of bio-resorption, mechanical strength and bio-compatibility. Zinc improves the bone activity of osteoblast, promotes the bone regeneration and also stimulates enzyme activity. In the present study Zn doped calcium pyrophosphate dihydrate (Zn-CPPD) nanoparticles were synthesized using surfactant mediated approach with varying [Zn]/[Ca] molar ratio as 0% (pure CPPD), 2%, 5% and, 10%. The crystalline nature and the average crystallite size was studied by Powder XRD. Zinc doping was confirmed by EDAX. The TEM study indicated that pure and Zn doped CPPD nanoparticles were in the range from 4 nm to 40 nm. The presence of various bonds was confirmed by FT-IR spectroscopy. The amount of water of hydration and the thermal stability was studied by thermo-gravimetry. Formation of other phases on heating CPPD at $900^{\circ}$C and $1250^{\circ}$C were identified by the powder XRD. Substitution of Zn content significantly affects the crystallinity and thermal stability of nanoparticles. The results are discussed

Some critical aspects of FT-IR, TGA, powder XRD, EDAX and SEM studies of calcium oxalate urinary calculi

237-243Urinary calculi constitute one of the oldest afflictions of humans as well as animals, which are occurring globally. The calculi vary in shape, size and composition, which influence their clinical course. They are usually of the mixed-type with varying percentages of the ingredients. In medical management of urinary calculi, either the nature of calculi is to be known or the exact composition of calculi is required. In the present study, two selected calculi were recovered after surgery from two different patients for detailed examination and investigated by using Fourier-Transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TGA), powder X-ray diffraction (XRD), scanning electron microscopy and energy dispersive analysis of X-rays (EDAX) techniques. The study demonstrated that the nature of urinary calculi and presence of major phase in mixed calculi could be identified by FT-IR, TGA and powder XRD, however, the exact content of various elements could be found by EDAX only

Carbon-free dry reforming of methane to syngas over NdCoO<SUB>3</SUB> perovskite-type mixed metal oxide catalyst

CoNdOx (Co/Nd = 1) is a highly promising catalyst for the carbon-free CO2 reforming of methane. Influence of the Co/Nd ratio on the catalyst performance in the CO2 reforming and also on the crystalline phases and reduction by temperature programmed reduction (TPR) of the CoNdOx catalyst has also been investigated. The CoNdOx (CoNd = 1.0) catalyst consisted of mainly NdCoO3 perovskite-type mixed metal oxide and it showed not only a high resistance to carbon formation at different process conditions (viz. temperature = 750-900° C and gas hourly space velocity (GHSV) = 10000-50000 cm3 g-1 h-1) but also high activity and selectivity in the CO2 reforming process. The high resistance to carbon formation for this catalyst is attributed mostly to strong metal (Co° )-support (Nd2O3) interactions

Giant exchange bias in antiferromagnetic Pr2CoFe0.5Mn0.5O6: a structural and magnetic properties study

Antiferromagnetic (AFM) materials with a colossal exchange bias (EB) effect find applications as high-density spintronic devices. We report structural (geometrical and electronic) and magnetic studies in the polycrystalline Pr2CoFe0.5Mn0.5O6 double perovskite system. The observed lack of training effect suggests the existence of robust EB. In addition, the detailed magnetic studies and Raman studies unravel the Griffith-like phase along with the spin-phonon coupling in the present system. The x-ray photoemission spectroscopy (XPS) analysis supports more than one valence state of B-site elements, which is accountable for the competition between ferromagnetic (FM) and AFM interactions in addition to the anti-site disorder in the system. The neutron measurement confirms the G-type AFM spin arrangement, accredited by the DFT calculation. The magnetic studies have correlated with the electronic structure, neutron study, and theoretical first principle calculations