Abstract: Provided herein are compounds of Formula (I), their pharmaceutically acceptable salts, and their pharmaceutical compositions: wherein R1, R2, R3a, R3b, R4, R5, and A are defined in the present disclosure. The compounds are potent inhibitors of the main protease (Mpro) of severe acute respiratory syndrome Coronavirus-2 (SARS-CoV-2), and they are useful in treating or preventing COVID-19 in a subject.

Abstract: A manure digester and power generating system includes a mixing tank for receiving manure, a closed, anaerobic manure digester tank of fixed volume, and a gas-fueled engine and a generator coupled to the engine, for generating electrical power. Manure is scraped into the mixing tank daily, where it is mixed with water to produce a manure slurry of desired consistency, and heated to a prescribed temperature. The digester tank is of fixed volume and may be of a generally rounded cross-sectional shape and elongated in length, and into its inflow end the contents of the mixing tank are transferred daily, on a daily batch basis. Anaerobic-digesting microbes are maintained in the digester tank to digest the manure slurry and produce methane gas and by-products. Temperature in the digester tank is maintained at about 90.degree. to 100.degree. F.