The present investigation is an attempt on synthesising iron oxide nanoparticles through greener mode using the petal extracts of Hibiscus rosa-sinensis and utilising them as fortificants in wheat biscuits. Ferric and ferrous chloride at a concentration of 0.025 M and at a ratio of 2:1 was used as the metal precursors and the extract was served as the reducing agent. Synthesised iron oxide nanoparticles were characterised using UV-visible spectroscopy, X-ray diffraction (XRD), FTIR spectroscopy and scanning electron microscopy (SEM). The analyses confirmed that the formed particles were nano sized and the crystallite size was found to be 6.16 nm through XRD studies. The formed nanoparticles were observed from SEM analysis to be spinel shaped with an average particle size of 65 nm. Biscuits were fortified with iron oxide nanoparticles which were later studied for physical and proximate analyses. The inductively coupled plasma optical emission spectroscopy studies revealed that the iron content was higher in fortified biscuits than that in control. Microbial analysis for 30 days indicated that the fortified biscuits could have a longer shelf life. In brief, the first report on use of iron oxide nanoparticles successfully suggested that their use as fortificants in food and could be prescribed for malnourished, iron deficit or anaemic patients.

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The α7 subtype of neuronal nicotinic acetylcholine receptor (nAChR) is a ligand-gated ion channel protein that is vital to various neurological functions, including modulation of neurotransmitter release. A relatively high concentration of extracellular Ca 2+ in the neuronal environment is likely to exert substantial structural and functional influence on nAChRs, which may affect their interactions with agonists and antagonists. In this work, we employed atomistic molecular dynamics (MD) simulations to examine the effects of elevated Ca 2+ on the structure and dynamics of α7 nAChR embedded in a model phospholipid bilayer. Our results suggest that the presence of Ca 2+ in the α7 nAChR environment results in closure of loop C-in the extracellular ligand-binding domain, a motion normally associated with agonist binding and receptor activation. Elevated Ca 2+ also alters the conformation of key regions of the receptor, including the inter-helical loops, pore-lining helices and the "gate" residues, and causes partial channel opening in the absence of an agonist, leading to an attendant reduction in the free energy of Ca 2+ permeation through the pore as elucidated by umbrella sampling simulations. Overall, the structural and permeability changes in α7 nAChR suggest that elevated Ca 2+ induces a partially activated receptor state that is distinct from both the resting and the agonist-activated states. These results are consistent with the notion that divalent ions can serve as a potentiator of nAChRs, resulting in a higher rate of receptor activation (and subsequent desensitization) in the presence of agonists, with possible implications for diseases involving calcium dysregulation. K E Y W O R D S divalent calcium ions, molecular dynamics simulations, nicotinic acetylcholine receptors, permeation, umbrella sampling