Active matter breaks mirror symmetry as cracking cement redirects water and a new catalyst splits lignin
Swarming cells spontaneously break mirror symmetry during topological defect formation, advancing cracks in wet cement actively pull water backward, and a non-precious metal catalyst efficiently yields catechols from C-lignin.
Science··Midday
Swarming bacteria and lung cells break mirror symmetry
Biological active matter constantly generates and resolves distinct structural irregularities known as topological defects. Researchers observing swarming bacteria and human bronchial epithelial cells discovered that the creation and annihilation of these defect pairs spontaneously break spatial mirror symmetry. Despite vastly different evolutionary origins and physical scales, the intrinsic polar forces inside both living systems drive this non-equilibrium phenomenon, generating measurable entropy and challenging classical nematic models of organization.[1]
A crack in wet cement pulls water back and doubles its cost to advance
In porous inorganic materials, mechanical failure is deeply coupled with the internal movement of fluids. When a crack begins to propagate through wet, fluid-saturated cement, it generates a localized drop in pressure directly ahead of the growing tip. This sudden underpressure physically pulls water backward, which reduces the effective stress near the tip and effectively doubles the mechanical energy required to advance the fracture further through the structure.[2]
A cobalt-zinc pair splits C-lignin without precious metal
Industrial processing of natural biopolymers often demands expensive chemical drivers to break particularly stubborn molecular bonds. A newly developed catalyst pairs cobalt and zinc atoms without relying on any precious metals, achieving an 84.6 per cent yield of catechols from raw C-lignin. The zinc and cobalt species operate sequentially to drive the cleavage of vicinal bonds, demonstrating a highly selective and sustainable method for upgrading complex plant materials.[3]
