https://www.selleckchem.com/ Throughout the central nervous system, astrocytes adopt precisely ordered spatial arrangements of their somata and arbors, which facilitate their many important functions. Astrocyte pattern formation is particularly important in the retina, where astrocytes serve as a template that dictates the pattern of developing retinal vasculature. Thus, if astrocyte patterning is disturbed, there are severe consequences for retinal angiogenesis and ultimately for vision - as seen in diseases such as retinopathy of prematurity. Here we discuss key steps in development of the retinal astrocyte population. We describe how fundamental developmental forces - their birth, migration, proliferation, and death - sculpt astrocytes into a template that guides angiogenesis. We further address the radical changes in the cellular and molecular composition of the astrocyte network that occur upon completion of angiogenesis, paving the way for their adult functions in support of retinal ganglion cell axons. Understanding development of retinal astrocytes may elucidate pattern formation mechanisms that are deployed broadly by other axon-associated astrocyte populations. Recent studies conducted in several OECD countries have shown that chronic exposure to elevated levels of air pollutants (especially PM , PM and NOx), might negatively impact COVID-19 morbidity and mortality rates. The aim of this study was to examine the association between chronic exposure to air pollution in Israeli cities and towns, their demographic and socioeconomic status, and COVID-19 morbidity, during the three local morbidity waves. We examined the associations between (a) annual average concentrations of NOx, CO, PM , PM and SO in 2016-2019, and demographic and socioeconomic parameters, and (b) COVID-19 positive cases in 279 Israeli cities and towns, in the four state-wide morbidity peaks 1 wave peak March 31 , 2020; 2 wave peaks July 24 and September 27 , 2020, and the 3 wave peak Januar