Measuring monopole and dipole polarizability of acoustic meta-atoms

© 2018 Author(s). We present a method to extract monopole and dipole polarizability from experimental measurements of two-dimensional acoustic meta-atoms. In contrast to extraction from numerical results, this enables all second-order effects and uncertainties in material properties to be accounted for. We apply the technique to 3D-printed labyrinthine meta-atoms of a variety of geometries. We show that the polarizability of structures with a shorter acoustic path length agrees well with numerical results. However, those with longer path lengths suffer strong additional damping, which we attribute to the strong viscous and thermal losses in narrow channels

Successful arthroscopic treatment of shoulder osteochondrosis in the dog

Fourteen shoulder joints in 12 dogs were treated arthroscopically for osteochondrosis. The arthroscopic procedure included removal of all osteochondral flaps and curettage of the edges of the subchondral defect. Histological examination of biopsy samples from eight joints revealed synovitis in all cases. Arthroscopic surgery of shoulder osteochondrosis in the dog proved to be a less time consuming procedure than arthrotomy with minimal soft tissue trauma and allowed a rapid return to function of the patients