A Polarization-Actuated Plasmonic Circulator.

A circulator for surface plasmon polaritons (SPPs) based on a plasmonic two-wire transmission-line (TWTL) structure is experimentally realized. A TWTL offers two distinct plasmon modes that can be independently excited, solely determined by the polarization of the laser field. Through controlled superposition of the two modes, TWTLs are exploited to enable polarization-actuated plasmonic circulators. In the first demonstration, the coupling antennas to the plasmonic circulator are designed to circulate SPPs sensitive to linearly polarized excitation. In the second design, the circulator reacts to the spin angular momenta carried by circularly polarized laser excitations. In both cases, the SPP circulation directions are directly controlled by the laser polarization, and the number of ports is easily expandable. Experimentally, a wide optical operational bandwidth of ∼100 nm is achieved. The results show a major step toward the realization of multifunctioning photonic nanocircuitry.

Aortitis and aortic aneurysm in systemic vasculitis.

The term "large-vessel vasculitis" refers to chronic inflammation affecting the elastic arteries, mainly aorta and its major branches. Large-vessel vasculitis affecting the aorta is termed as "aortitis." This leads to diffuse wall thickening, loss of elasticity, stenosis, occlusion, dissection, calcification or aneurysm formation. Vasculitis involving the aorta includes Takayasu arteritis (commonest large-vessel vasculitis in India), giant cell arteritis (GCA), the periaortitis spectrum (including inflammatory abdominal aortic aneurysm), rheumatic diseases and IgG4-related disease. It is important for physicians to be aware of the aortic manifestations of common vasculitis-so that clinically relevant aortic involvement is not missed. Also, it is equally important for surgeons to keep in mind that aortic aneurysms can have an inflammatory aetiology. The primary reason for this is the central role that immunosuppressive therapy plays in the management of inflammatory aortic aneurysms. Surgical or percutaneous interventions, when needed, are most likely to succeed when performed after activity control; perioperative steroids may be beneficial in select cases, and postoperative disease activity control is imperative.