Lessons learned in delayed identification of a misplaced electrode array in the vestibule.

To report a case of cochlear implantation with a misplaced electrode array in the vestibule and the causes for the delay in identification. A 23-year-old male with left single-sided deafness underwent cochlear implantation. The intraoperative assessment did not reveal any major red flags of electrode array misplacement.

Double-pass Mach-Zehnder fiber interferometer pH sensor.

A biocompatible fiber-optic pH sensor based on a unique double-pass Mach-Zehnder interferometer is proposed. pH responsive poly(2-hydroxyethyl methacrylate-co-2-(dimethylamino)ethyl methacrylate) hydrogel coating on the fiber swells/deswells in response to local pH, leading to refractive index changes that manifest as shifting of interference dips in the optical spectrum. The pH sensor is tested in spiked phosphate buffer saline and demonstrates high sensitivity of 1.