Development and Assessment of an Inexpensive Smartphone-Based Respiratory Droplet Simulation Model.

Background. Droplet simulation often requires expensive and inaccessible equipment. Herein, we develop and assess a low-cost droplet simulation model using easily accessible materials, open-source software, and a smartphone-based cobalt blue light. Methods. The simulation model was developed using commercial-grade materials and fluorescein dye. A clear face shield was assessed ten times following a simulated cough using fluorescein dye. A conventional ultraviolet Woods lamp was compared to a smartphone-based cobalt blue light to detect fluorescein illumination. Results. The simulation platform and smartphone-based cobalt blue light cost $20.18. A Wilcoxon signed rank test revealed that the median droplet area of fluorescence under the UV Wood's lamp was not significantly different than that of the smartphone-based cobalt blue light (2.89 vs 2.94, P = .386). Conclusions. This simulation model is inexpensive and easily reproducible. The smartphone application may be a convenient alternative to standard ultraviolet lights. This model has great potential for use in financially restricted academic centers during the COVID-19 pandemic and beyond.

Safety assessment of trans-tympanic photobiomodulation.

We evaluated functional and morphological changes after trans-tympanic laser application using several different powers of photobiomodulation (PBM). The left (L) ears of 17 rats were irradiated for 30 min daily over 14 days using a power density of 909.1 (group A, 5040 J), 1136.4 (group B, 6300 J), and 1363.6 (group C, 7560 J) mW/cm(2). The right (N) ears served as controls. The safety of PBM was determined by endoscopic findings, auditory brainstem response (ABR) thresholds, and histological images of hair cells using confocal microscopy, and light microscopic images of the external auditory canal (EAC) and tympanic membrane (TM). Endoscopic findings revealed severe inflammation in the TM of C group; no other group showed damage in the TM. No significant difference in ABR threshold was found in the PBM-treated groups (excluding the group with TM damage). Confocal microscopy showed no histological difference between the AL and AN, or BL and BN groups. However, light microscopy showed more prominent edema, inflammation, and vascular congestion in the TM of BL ears. This study found a dose-response relationship between laser power parameters and TM changes. These results will be useful for defining future allowance criteria for trans-tympanic laser therapies.