WASHINGTON, Sept. 21 -- The Proceedings of the National Academy of Sciences, a peer-reviewed scientific journal, published research articles on the following topics in its Sept. 28, 2021 edition:

Physical Sciences:

* Deep learning for early warning signals of tipping points

* Electrophilic aromatic substitution reactions of compounds with Craig-Mobius aromaticity

* Deep learning identifies synergistic drug combinations for treating COVID-19