RESUMO
We present optical studies of two different size distributions of silver triangular nanoprisms, one with a dipole resonance at 520 nm and the other with a dipole resonance at 650 nm, placed in different media. Significant wavelength-dependent depolarization of scattered light from the silver nanoprisms suspended in water indicates strong interference of multiple surface plasmon resonant modes in the same particle. We use this depolarization as a probe of light scattering by the nanoprisms in a lipid solution due to the rejection of a polarized background scattering. Also, the silver nanoprisms were embedded in a polyvinyl alcohol polymer matrix and oriented by stretching the polymer/nanoprism nanocomposite films. We observe significantly increased linear dichroism in the region associated with the plasmonic in-plane dipole mode upon stretching. Additionally, there is a weaker linear dichroism in the region associated with out-of-plane modes, which vanish in the extinction spectrum of the stretched nanocomposite film.
RESUMO
Most peripheral pseudoaneurysms are iatrogenic or, less commonly, post-traumatic. Pseudoaneurysms are associated with characteristic findings of a pulsatile palpable mass and an audible to and fro murmur. The diagnosis can be easily confirmed using colour duplex ultrasound. A successful treatment for the coagulation of pseudoaneurysms as an alternative to ultrasound-guided manual compression is described. The method involves ultrasound-guided direct percutaneous injection of a small quantity of thrombin through a fine needle. This technique is simple and effective, resulting in rapid occlusion of the pseudoaneurysm. Two cases are reported.
