Pierre Deymier

Static superlattices that do not break time-reversal symmetry can support robust topologically protected elastic waves with non-zero amplitude in the forward propagating direction but zero amplitude in the opposite direction. We form a prototypical acoustic wave device by sandwiching a finite superlattice that supports one-way propagating waves between input and detector layers. Compared to conventional elastic waves, topologically protected waves provide a significant benefit for reducing the return loss of the prototypical device. Superlattices supporting topologically protected acoustic waves provide attractive and disruptive solutions for designing the next-generation of low-loss acoustic wave devices for telecommunication or sensing.

Bone mineralization is critical to maintaining tissue mechanical function. The application of mechanical stress via exercise promotes bone mineralization via cellular mechanotransduction and increased fluid transport through the collagen matrix. However, due to its complex composition and ability to exchange ions with the surrounding body fluids, bone mineral composition and crystallization is also expected to respond to stress. Here, a combination of data from materials simulations, namely density functional theory and molecular dynamics, and experimental studies were input into an equilibrium thermodynamic model of bone apatite under stress in an aqueous solution based on the theory of thermochemical equilibrium of stressed solids. The model indicated that increasing uniaxial stress induced mineral crystallization. This was accompanied by a decrease in calcium and carbonate integration into the apatite solid. These results suggest that weight-bearing exercises can increase tissue mineralization via interactions between bone mineral and body fluid independent of cell and matrix behaviours, thus providing another mechanism by which exercise can improve bone health. This article is part of a discussion meeting issue ‘Supercomputing simulations of advanced materials’.