Objective Signal Analysis for Investigating Feasibility of Active Noise Cancellation in Hearing Screening.

With the development of active noise cancellation (ANC) technology, ANC has been used to mitigate the effects of environmental noise on audiometric results. However, objective evaluation methods supporting the accuracy of audiometry for ANC exposure to different levels of noise have not been reported. Accordingly, the audio characteristics of three different ANC headphone models were quantified under different noise conditions and the feasibility of ANC in noisy environments was investigated. Steady (pink noise) and non-steady noise (cafeteria babble noise) were used to simulate noisy environments. We compared the integrity of pure-tone signals obtained from three different ANC headphone models after processing under different noise scenarios and analyzed the degree of ANC signal correlation based on the Pearson correlation coefficient compared to pure-tone signals in quiet. The objective signal correlation results were compared with audiometric screening results to confirm the correspondence. Results revealed that ANC helped mitigate the effects of environmental noise on the measured signal and the combined ANC headset model retained the highest signal integrity. The degree of signal correlation was used as a confidence indicator for the accuracy of hearing screening in noise results. It was found that the ANC technique can be further improved for more complex noisy environments.

Visual semiquantification via the formation of phase segregation.

Colorimetry, one of the central themes in contemporary chemistry, generally relies on spectrometers to quantify specimens of interest. Developed herein is a rapid screening scheme to determine whether the amount of an analyte falls into a diagnostic concentration range by the naked eye. This is particularly important for applications under circumstances where instruments are not readily available. The aforementioned goal is demonstrated by utilizing copper-thiol chemistry as a model system in which polymerization occurs within a certain range of copper-to-cysteine mole ratios; hence, the targeted range of copper concentration is tunable by adjusting the amount of cysteine. Within and outside the range, the solutions appear cloudy and homogeneous, respectively. The reaction mechanism is proposed and scrutinized. The detection scheme is applied successfully on samples of human serum (15.7-23.6 µM) and pond water (<3.0 ppm or 47 µM) with a handy laser pointer.