The cracking of Scots pine () cones.

Pine cones show functionally highly resilient, hygroscopically actuated opening and closing movements, which are repeatable and function even in millions of years old, coalified cones. Although the functional morphology and biomechanics behind the individual seed scale motions are well understood, the initial opening of the cone, which is often accompanied by an audible cracking noise, is not. We therefore investigated the initial opening events of mature fresh cones of Scots pine () and their subsequent motion patterns.

A Simply Synthesized, Tough Polyarylene with Transient Mechanochromic Response.

A simple and high-yielding route to tough polyarylenes of the type poly(meta,meta,para-phenylene) (PmmpP) is developed. PmmpP is tough even in its as-synthesized state which has an intermediate molar mass of M ≈60 kg mol and exhibits outstanding mechanical properties at further optimized molecular weight of M =96 kg mol , E=0.9 GPa, ϵ=300 %.