Mechanical Properties of Differently Nanostructured and High-Pressure Compressed Hydroxyapatite-Based Materials for Bone Tissue Regeneration

Hydroxyapatite (HAp) has long been considered the gold standard in the biomedical field, considering its composition and close resemblance to human bone. However, the brittle nature of hydroxyapatite (HAp) biomaterial, constrained by its low fracture toughness (of up to 1.2 vs. 2–12 MPa m1/2 of human bone), remains one of the significant factors impairing its use in bone regeneration. In the present study, HAp nanoparticles synthesized by the solid-state (SHAp) and sonochemical (EHAp) approaches using eggshell-derived calcium hydroxide and ammonium dihydrogen orthophosphate as precursors are compared with those synthesized using commercially available calcium hydroxide and ammonium dihydrogen orthophosphate as precursors (CHAp) employing sonochemical method. The HAp samples were then compressed into compact materials using a uniaxial high-pressure compression technique at a preoptimized load and subsequently characterized for mechanical properties using the Vickers indentation method and compressive strength testing. The analysis revealed that the material with smaller particle size (30–40 nm) and crystalline nature (EHAp and CHAp) resulted in mechanically robust materials (σm = 54.53 MPa and 47.72 MPa) with high elastic modulus (E = 4011.1 MPa and 2750.25 MPa) and density/hardness-dependent fracture toughness (σf = 4.34 MPa m1/2and 6.57 MPa m1/2) than SHAp (σm =28.40 MPa, E = 2116.75 MPa, σf = 5.39 MPa m1/2). The CHAp material was found to be the most suitable for applications in bone regeneration.

DEVELOPMENT OF LIQUID CHROMATOGRAPHIC METHOD FOR ESTIMATION OF ACAMPROSATE CALCIUM AND BACLOFEN COMBINATION USED IN TREATMENT OF NEUROLOGICAL DISORDERS

A specific, accurate, precise, and reproducible liquid chromatographic method has been developed and validated for the estimation of acamprosate calcium and baclofen in combination. The separation was achieved using stationary phase Phenomenex C18 column (150 mm× 4.6 mm.) in isocratic mode, with mobile phase containing 0.05 M potassium dihydrogen orthophosphate buffer (pH 7) : acetonitrile (10:90 V/V), at a flow rate of 1.0 mL/min and effluents were monitored at 210 nm. The retention time of acamprosate calcium and baclofen were found to be 1.9 min and 5.3 min, respectively. The linearity for acamprosate calcium and baclofen were in the range of 2-64 µg/mL and 1.2- 38.4 µg/mL, respectively. The method was validated as per ICH guideline. The recoveries of Acamprosate calcium and baclofen were found in the range of 98.90 - 100.13 % and 98.60 -100.02 %, respectively. The method was successfully applied for the determination of both the drugs in combination.

Indian Ocean Rim Association

The Indian Ocean Rim Association (IORA) is a regional forum that focuses on bringing together representatives of government, business, and academia, for promotion purposes. It depends on the principles of open regionalism for strengthening trade facilitation and investment, promotion, and social development of the region. Social, cultural, political, geographical, and economic linkages exist between 22 member nations. The main objective of this chapter is analyzing India's trade potential with IORA member nations. The main outcome of this chapter is that India should concentrate on ammonium dihydrogen orthophosphate for Australia, gold and semi-manufactured for Singapore, mineral or chemical fertilizers for Thailand, tankers for Malaysia, warp knit fabrics of synthetic fibers for Indonesia, ammonium dihydrogen orthophosphate for South Africa, palm oil and fractions for Sri Lanka, Bangladesh, Mozambique, Tanzania, the United Republic of Yemen, crude palm oil for Kenya, bigeye tunas, frozen for Mauritius, and carded yarn of fine animal hair for Madagascar.

A Study on Spectral and Morphological Analysis on Unidirectional Neodymium Doped KDP Single Crystal

A nonlinear optical unidirectional <101> Single crystal of Neodymium doped Potassium dihydrogen orthophosphate (KDP) was grown by Sankaranarayanan-Ramasamy (SR) method. The <101> oriented seed crystals were mounted at the bottom of the glass ampoule and the crystal of 16mm diameter; 120mm length were grown by SR method. The laser damage threshold was measured using Q-switched Nd:YAG laser (1064 nm) and was found to be 5.456 Gwcm-2 respectively.The presence of functional groups was examined by Fourier transform infrared (FTIR) analysis. The surface morphology and dislocations along <101> plane was observed using Scanning electron microscope (SEM) and Transmission electron microscope (TEM).

Mechanical Properties and Cytotoxicity of Differently Structured Nanocellulose-hydroxyapatite Based Composites for Bone Regeneration Application

The nanocomposites were prepared by synthesizing (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO)-oxidized cellulose nanofibrils (TCNFs) or cellulose nanocrystals (CNCs) with hydroxyapatite (HA) in varying composition ratios in situ. These nanocomposites were first obtained from eggshell-derived calcium and phosphate of ammonium dihydrogen orthophosphate as precursors at a stoichiometric Ca/P ratio of 1.67 with ultrasonication and compressed further by a uniaxial high-pressure technique. Different spectroscopic, microscopic, and thermogravimetric analyses were used to evaluate their structural, crystalline, and morphological properties, while their mechanical properties were assessed by an indentation method. The contents of TCNF and CNC were shown to render the formation of the HA crystallites and thus influenced strongly on the composite nanostructure and further on the mechanical properties. In this sense, the TCNF-based composites with relatively higher contents (30 and 40 wt %) of semicrystalline and flexible TCNFs resulted in smoother and more uniformly distributed HA particles with good interconnectivity, a hardness range of 550–640 MPa, a compression strength range of 110–180 MPa, an elastic modulus of ~5 GPa, and a fracture toughness value of ~6 MPa1/2 in the range of that of cortical bone. Furthermore, all the composites did not induce cytotoxicity to human bone-derived osteoblast cells but rather improved their viability, making them promising for bone tissue regeneration in load-bearing applications.