Masking of Korotkoff sounds used in blood pressure measurement through auscultation.

Measurement of blood pressure (BP) through manual auscultation and the observation of Korotkoff sounds (KSs) remains the gold standard in BP methodology. Critical to determining BP levels via auscultation is the determination of KS audibility. While absolute sound level audibility is well researched, the problem has not been approached from the point of view of psychoacoustic masking of the sounds.

Efficient actuation design for optomechanical sensors.

For any nanomechanical device intended for sensing applications, actuation is an important consideration. Many different actuation mechanisms have been used, including self-oscillation, piezoelectric shakers, capacitive excitation, and optically pumping via the optical gradient force. Despite the relatively frequent use of optical pumping, the limits of optical actuation with a pump laser have not been fully explored.

Optimum waveform envelopes and amplitude ratios in oscillometric blood pressure estimation.

Objective: To determine if, when using the oscillometric method, there is a specific range of amplitude ratios in the fixed-ratio algorithm that will result in blood pressure estimates that consistently fall within a mean error ≤5 mmHg and a SD of the error <8 mmHg. Additionally, to apply different representations of the oscillometric waveform envelope to verify if this will affect the accuracy of the results.

Methods: SBP and DBP were obtained using the fixed-ratios method applied to a dataset of 219 oscillometric measurements obtained from 73 healthy volunteers and compared to their corresponding auscultation values.

Transduction of large optomechanical amplitudes with racetrack-loaded Mach-Zehnder interferometers.

Chip-integrated photonic devices have stimulated development in areas ranging from telecommunications to optomechanics. Racetrack resonators have gained popularity for optomechanical transduction due to their high sensitivity and cavity finesse. However, they lack sufficient dynamic range to read out large amplitude mechanical resonators, which are preferred for sensing applications.

Porous Nanophotonic Optomechanical Beams for Enhanced Mass Adsorption.

We have developed a porous silicon nanocantilever for a nano-optomechanical system (NOMS) with a universal sensing surface for enhanced sensitivity. Using electron beam lithography, we selectively applied a VO/HF stain etch to the mechanical elements while protecting the silicon-on-insulator photonic ring resonators. This simple, rapid, and electrodeless approach generates tunable device porosity simultaneously with the mechanical release step.