Sirianni received her first federal research grant more than a decade earlier and had never even had an application-review meeting postponed. She scrambled to learn anything she could about the status of her proposals. This turned out to be difficult, because the new administration had ordered the N.I.H. to temporarily cease all external communications. Scientists were unsure whether they could even speak with program officers at the agency. Sirianni, who is now 40, started college when she was 13. For more than two decades, she had spent as many as 12 hours a day in a lab, hunched over microscopes,...