during fixation of a femoral neck fracture in a 23-year-old male patient with cannulated screws, a broken guide wire fragment inadvertently advanced through the hip joint and protruded into the pelvis. a second surgical approach was needed to remove the broken fragment from the pelvis. awareness of such a potentially devastating complication will make surgeons more cautious during implementatio...

We review some approaches to macroscopic irreversibility from reversible microscopic dynamics, introducing the contribution of time dependent perturbations within the framework of recent developments in non-equilibrium statistical physics. We show that situations commonly assumed to violate the time reversal symmetry (presence of magnetic fields, rotating reference frames, and some time depende...

Nonlinear optical responses are commonly used as a probe for studying the electronic properties of materials. For topological materials, studies thus far focused on photogalvanic electric currents, which forbidden in centrosymmetric materials because they require broken inversion symmetry. In this Letter, we propose class symmetry-allowed inversion-symmetric insulators with two doubly degenerat...