The study evaluated the mechanical, tribological, and cytocompatibility properties of silver nanoparticles and titanium dioxide nanoparticles reinforced into polymethyl methacrylate resin. Both nanoparticles were separately ball-milled with polymethyl methacrylate, and a conventional compression molding technique prepared samples in a thermostatically controlled water bath. Samples were analyzed for flexural strength, polishability, three-body abrasive wear, surface hardness, and cytotoxicity. The fracture mechanics and surface roughness were further analyzed using a field emission scanning electron microscope. Most properties showed improvement at the said concentration compared to the control group, while few did not show property enhancement.The cell proliferation and viability were not compromised. Within study limits, silver nanoparticles and titanium dioxide nanoparticles reinforced polymethyl methacrylate resin positively influenced the dental polymer to a certain extent.The nanocomposite is cytocompatible at the tested concentrations. Prereaction of the polymer, treating nanoparticles with coupling agents, determining an optimal additive size and concentration, and use of effective dispersion technique may further enhance the properties of the nanocomposites.

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The study aimed at developing a cytocompatible dental polymer composite with high mechanical and surface characteristics by reinforcing polymethyl methacrylate resin with graphene nanoplatelets and montmorillonite nanoclay. After ball milling the particles into the polymer samples were prepared via conventional compression molding method. Samples were tested for flexural strength, polishability, fatigue failure, wear, hardness, and cytotoxicity. The fracture mode and surface polish were tested using a field emission scanning electron microscope. Most properties displayed enhancement at the tested fraction weight in relation to the control, while some properties were downgraded. However, the tested polymer composite was cytocompatible at all concentrations. Within study limits, graphene nanoplatelets and montmorillonite nanoclay reinforced polymer brought about a positive effect to a particular degree. Establishing optimal concentration of reinforcement and alternate blending methods may boost the resultant characteristics of the resin composite.

It remains a mystery why estrogen hormone receptors (ERs), which are highly specific toward its endogenous hormones, are responsive to chemically distinct exogenous agents. Does it indicate that ERs are environmentally regulated? Here, we speculate that ERs would have some common structural features with prokaryotic taxis receptor responsive toward environmental signals. This study addresses the low specificity and high responsiveness of ERs toward chemically distinct exogenous substances, from an evolutionary point of view. Here, we compared the ligand binding domain (LBD) of ER alpha (α) with the LBDs of prokaryotic taxis receptors to check if LBDs share any structural similarity. Interestingly, a high degree of similarity in the domain structural fold architecture of ERα and bacterial taxis receptors was observed. The pharmacophore modeling focused on ligand molecules of both receptors suggest that these ligands share common pharmacophore features. The molecular docking studies suggest that the natural ligands of bacterial chemotaxis receptors exhibit strong interaction with human ER as well. Although phylogenetic analysis proved that these proteins are unrelated, they would have evolved independently, suggesting a possibility of convergent molecular evolution. Nevertheless, a remarkable sequence divergence was seen between these proteins even when they shared common domain structural folds and common ligand-based pharmacophore features, suggesting that the protein architecture remains conserved within the structure for a specific function irrespective of sequence identity.