Macroscopic quorum sensing sustains differentiating embryonic stem cells.

Cells can secrete molecules that help each other's replication. In cell cultures, chemical signals might diffuse only within a cell colony or between colonies. A chemical signal's interaction length-how far apart interacting cells are-is often assumed to be some value without rigorous justifications because molecules' invisible paths and complex multicellular geometries pose challenges. Here we present an approach, combining mathematical models and experiments, for determining a chemical signal's interaction length. With murine embryonic stem (ES) cells as a testbed, we found that differentiating ES cells secrete FGF4, among others, to communicate over many millimeters in cell culture dishes and, thereby, form a spatially extended, macroscopic entity that grows only if its centimeter-scale population density is above a threshold value. With this 'macroscopic quorum sensing', an isolated macroscopic, but not isolated microscopic, colony can survive differentiation. Our integrated approach can determine chemical signals' interaction lengths in generic multicellular communities.

Evolution of incidence of audiovestibular disorders during the pandemic COVID-19 period.

PURPOSE: Despite sporadic case reports describing hearing problems in patients with coronavirus disease 2019 (COVID-19), whether COVID-19 affects the audiovestibular system remains unclear. This study assessed the evolution of incidence of audiovestibular disorders during the pandemic COVID-19 period. METHOD: Three audiovestibular disorders namely, sudden sensorineural hearing loss (SSHL), autonomic dysfunction, and Meniere's disease (MD) were analyzed and compared from 2016 to 2020. RESULTS: The annual new cases at our clinic comprised overall 2107, 1997, 1984, 2068, and 1829 from 2016 to 2020, respectively, and the respectively annual cases of SSHL were 54, 46, 42, 45 and 38. Accordingly, annual incidences of SSHL in relation to overall cases of audiovestibular disorders were 2.6%, 2.3%, 2.1%, 2.2% and 2.1% from 2016 to 2020, respectively, exhibiting a non-significant difference (p > 0.05). In contrast, incidence of autonomic dysfunction in the year 2020 was 15.3%, which revealed significantly higher than 8.5-13.1% from 2016 to 2019 (p < 0.001). Restated, the incidence of autonomic dysfunction in 2020 displayed a significantly higher percentage than the other 4 years. Conversely, the incidence of MD in 2020 was 9.8%, showing a significant decline compared with the other 4 years (12.6-15.6% from 2016 to 2019, p < 0.001), CONCLUSION: Evolution of incidence of audiovestibular disorders during the pandemic COVID-19 period revealed increase in the incidence of autonomic dysfunction and decrease in that of MD, while incidence of SSHL remained unchanged from 2016 to 2020. Thus, the SARS-CoV-2 may less affect the audiovestibular system.

Time-Division Multiplexing Light Field Display with Learned Coded Aperture.

Conventional stereoscopic displays suffer from vergence-accommodation conflict and cause visual fatigue. Integral-imaging-based displays resolve the problem by directly projecting the sub-aperture views of a light field into the eyes using a microlens array or a similar structure. However, such displays have an inherent trade-off between angular and spatial resolutions. In this paper, we propose a novel coded time-division multiplexing technique that projects encoded sub-aperture views to the eyes of a viewer with correct cues for vergence-accommodation reflex. Given sparse light field sub-aperture views, our pipeline can provide a perception of high-resolution refocused images with minimal aliasing by jointly optimizing the sub-aperture views for display and the coded aperture pattern. This is achieved via deep learning in an end-to-end fashion by simulating light transport and image formation with Fourier optics. To our knowledge, this work is among the first that optimize the light field display pipeline with deep learning. We verify our idea with objective image quality metrics (PSNR, SSIM, and LPIPS) and perform an extensive study on various customizable design variables in our display pipeline. Experimental results show that light fields displayed using the proposed technique indeed have higher quality than that of baseline display designs.