Quantitation of ethanol in UTI assay for volatile organic compound detection by electronic nose using the validated headspace GC-MS method.

Disease detection through gas analysis has long been the topic of many studies because of its potential as a rapid diagnostic technique. In particular, the pathogens that cause urinary tract infection (UTI) have been shown to generate different profiles of volatile organic compounds, thus enabling the discrimination of causative agents using an electronic nose. While past studies have performed data collection on either agar culture or jellified urine culture, this study measures the headspace volume of liquid urine culture samples. Evaporation of the liquid and the presence of background compounds during electronic nose (e-nose) device operation could introduce variability to the collected data. Therefore, a headspace gas chromatography-mass spectrometry method was developed and validated for quantitating ethanol in the headspace of the urine samples. By leveraging the new method to characterize the sample stability during e-nose measurement, it was revealed that ethanol concentration dropped more than 15% after only three measurement cycles, which equal 30 minutes for this study. It was further shown that by using only data within the first three cycles, better accuracies for between-day classification were achieved, which was 73.7% and 97.0%, compared to using data from within the first nine cycles, which resulted in 65.0% and 81.1% accuracies. Therefore, the newly developed method provides better quality control for data collection, paving ways for the future establishment of a training data library for UTI.

Assessment of feedback modalities for wearable visual aids in blind mobility.

Sensory substitution devices engage sensory modalities other than vision to communicate information typically obtained through the sense of sight. In this paper, we examine the ability of subjects who are blind to follow simple verbal and vibrotactile commands that allow them to navigate a complex path. A total of eleven visually impaired subjects were enrolled in the study. Prototype systems were developed to deliver verbal and vibrotactile commands to allow an investigator to guide a subject through a course. Using this mode, subjects could follow commands easily and navigate significantly faster than with their cane alone (p <0.05). The feedback modes were similar with respect to the increased speed for course completion. Subjects rated usability of the feedback systems as "above average" with scores of 76.3 and 90.9 on the system usability scale.