Out of necessity, healthcare workers have been reusing N95 respirators—the dome-shaped, tight-fitting masks that are the only verified way to efficiently filter small particles like viruses.

School mask mandates have become something of a political lightning rod in the United States during the COVID-19 pandemic—and, in recent weeks, the dominos have started to fall as one state ...

State Key Laboratory of Ultra-Precision Machining Technology, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong 999077, China ...