Tapash R. Rautray

Surface modification of titanium and titanium alloys by ion implantation

Titanium and titanium alloys are widely used in biomedical devices and components, especially as hard tissue replacements as well as in cardiac and cardiovascular applications, because of their desirable properties, such as relatively low modulus, good fatigue strength, formability, machinability, corrosion resistance, and biocompatibility. However, titanium and its alloys cannot meet all of the clinical requirements. Therefore, to improve the biological, chemical, and mechanical properties, surface modification is often performed. In view of this, the current review casts new light on surface modification of titanium and titanium alloys by ion beam implantation.

Synthesis of spherical hydroxyapatite granules with interconnected pore channels using camphene emulsion.

The aim of this study was to fabricate porous spherical hydroxyapatite (HA) granules with interconnected pore channels for use as a bone graft substitute. Various weights of camphene porogen were mixed with nano-sized HA powder (camphene/HA = 0, 10, 30, 50, 70, and 90% w/w) and 10% gelatin aqueous solution then added to the mixture. The water-in-oil emulsion method was employed to obtain spherical-shaped granules, of which those 1000-2000 μm in diameter were selectively classified using a standard sieve set. Thermogravimetric analysis and X-ray diffraction were used to determine optimal sintering conditions. The sintered granules were characterized using field emission-scanning electron microscopy (FE-SEM), microcomputed tomography, and porosimetry. The pore size and porosity of spherical HA granules increased with the addition of camphene. Granules with a HA/camphene ratio of 90% (HG90) demonstrated macropores (>50 μm) with interconnected pore channels (porosity: 58.49%). In addition, FE-SEM examination of HG90 coated with polycaprolactone showed that the granule may hold promise as a drug delivery carrier. We concluded that these HG90 granules merit consideration as a bone graft substitute or drug delivery carrier in bone tissue engineering.

Surface characteristics and biological studies of hydroxyapatite coating by a new method

Hydroxyapatite was coated on the Ti implants by a new coating method called low temperature high speed collision (LTHSC). Higher roughness values were estimated in the formed thick coating on the implant surface. While the roughness value was lower than plasma sprayed HA coatings, LTHSC HA-coated surface showed higher hydrophilicity. The cell proliferation of oseteoblastic cells evaluated by MTT assay showed that HA-coated surface had significantly higher cell viability than the control. The HA-coated surface showed higher mean total protein production even though there was no statistical difference between two surfaces. Osteoblast differentiation, ALP activity and expression of differentiation marker genes such as osteopontin and osteocalcin were elevated in the cells cultured on HA-coated surface and this surface also showed higher collagen protein expression than titanium control. Moreover, in experimental group, BIC values were significantly increased after 12 weeks of implantation and about 30-50% cortical bone-implant contact was observed.

Elemental analysis of silver coins by PIXE technique.

Elemental analysis of nine Indian silver coins during British rule was carried out by proton induced X-ray emission spectroscopy. Eight elements, namely Cr, Fe, Ni, Cu, Zn, As, Ag, and Pb were determined in the present study. Ag and Cu were found to be the major elements, Zn was the only minor element and all other elements are present at the trace level. The variation of the elemental concentration may be due to the use of different ores for making coins.

Elemental analysis of coal and coal ASH by PIXE technique.

Coal and coal ash samples were characterized by particle induced X-ray emission spectroscopic technique. Sixteen elements, namely K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, As, Rb, Sr, Y and Pb were quantified in this study. Elements like K, Ca, Ti and Fe were present as major elements, whereas, other elements like V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Rb, Sr and Pb were present in trace level. The enrichment ratio of different ash samples with respect to coal were also estimated and discussed.

Analysis of ancient Indian silver punch-marked coins by external PIXE

Seven silver punch-marked coins were analysed using external particle induced X-ray emission technique. The main group of elements like Ag, Cu, Au, Pb and Fe were estimated along with a number of trace/minor elements such as K, Ca, Ti, V, Cr, Mn, Co, Ni and Rb in the analysed silver coins. Gold was found in all the coins and varied between 0.7% and 6.2% indicating the better economic condition of that civilisation.

ANALYSIS OF INDIAN SILVER COINS BY EDXRF TECHNIQUE

The analysis of some of the Indian silver coins during British rule were analysed by Energy Dispersive X-Ray Fluorescence Technique. Eight elements namely Cr, Fe, Ni, Cu, Zn, As, Ag and Pb were estimated in this study which also seems to indicate the fragmentation as well as the impoverishment of the power for the regimes that had produced the studied coins. While Cu and Ag were present as major elements, other elements were found to be present in minor concentration.