Fe-Fe Double-Atom Catalysts for Murine Coronavirus Disinfection: Nonradical Activation of Peroxides and Mechanisms of Virus Inactivation.

Peroxides find broad applications for disinfecting environmental pathogens particularly in the COVID-19 pandemic; however, the extensive use of chemical disinfectants can threaten human health and ecosystems. To achieve robust and sustainable disinfection with minimal adverse impacts, we developed Fe single-atom and Fe-Fe double-atom catalysts for activating peroxymonosulfate (PMS). The Fe-Fe double-atom catalyst supported on sulfur-doped graphitic carbon nitride outperformed other catalysts for oxidation, and it activated PMS likely through a nonradical route of catalyst-mediated electron transfer. This Fe-Fe double-atom catalyst enhanced PMS disinfection kinetics for inactivating murine coronaviruses (i.e., murine hepatitis virus strain A59 (MHV-A59)) by 2.17-4.60 times when compared to PMS treatment alone in diverse environmental media including simulated saliva and freshwater. The molecular-level mechanism of MHV-A59 inactivation was also elucidated. Fe-Fe double-atom catalysis promoted the damage of not only viral proteins and genomes but also internalization, a key step of virus lifecycle in host cells, for enhancing the potency of PMS disinfection. For the first time, our study advances double-atom catalysis for environmental pathogen control and provides fundamental insights of murine coronavirus disinfection. Our work paves a new avenue of leveraging advanced materials for improving disinfection, sanitation, and hygiene practices and protecting public health.

With Anchors Aweigh, Synchronous Instruction Preferred by Naval Academy Instructors in Small Undergraduate Chemistry Classes

The U.S. Naval Academy matriculates similar to 1,100 new undergraduate students each year, all of whom are required to complete two semesters of introductory chemistry, regardless of major selection. Thus, each of the similar to 50 sections of introductory chemistry comprises students with a broad range of interests, prior chemistry experience, and analytical skills. A survey of 28 chemistry instructors that taught introductory and upper-level courses remotely in the wake of the COVID-19 pandemic showed that most met with their students during every scheduled class period and delivered new content synchronously, though methods of instruction varied widely within those parameters. Student engagement decreased in the remote environment, but a small number of instructors reported improvements when a web-based classroom response system was implemented. Extra instruction was requested by fewer students, was generally conducted in group sessions, and was more time-consuming for the faculty. Most faculty teaching introductory chemistry used more multiple-choice assessments than they would in a live setting, because of compatibility with online testing platforms, and most faculty reported little evidence of academic dishonesty during online teaching, in spite of negative preconceptions. The dominant faculty perception is that student performance did not decline after the switch to online learning. Collaborative, supportive, and frequent communication among faculty and staff in the chemistry department was instrumental in facilitating the transition to online teaching.