Harvard medical researcher Soumya Raychaudhuri, of Brookline, Mass., pauses during an interview at Brigham and Women's Hospital in Boston on Tuesday, Jan. 31, 2017. Raychaudhuri awaits the fate of a new hire, Samira Asgari, an Iranian national who was not allowed to board a flight in Switzerland to Boston due to the travel ban issued by President Donald Trump. (AP Photo/Steven Senne)
Harvard medical researcher Soumya Raychaudhuri, of Brookline, Mass., pauses during an interview at Brigham and Women's Hospital in Boston on Tuesday, Jan. 31, 2017. Raychaudhuri awaits the fate of a new hire, Samira Asgari, an Iranian national who was not allowed to board a flight in Switzerland to Boston due to the travel ban issued by President Donald Trump. (AP Photo/Steven Senne) Credit: Steven Senne

BOSTON — Harvard Medical School professor Thomas Michel was so excited about recruiting Iranian researcher Soheil Saravi, he put Saravi’s name on the door of his Boston lab when his new hire got his visa.

Then President Donald Trump’s travel ban took effect, blocking Saravi from entering the U.S.

“It’s interesting. This is a door. It’s open,” Michel said Tuesday. But he added this lament: “He can’t walk through the door into this country to walk into this laboratory.”

Trump’s ban on people from Iran and six other predominantly Muslim countries has frustrated academics like Michel, who feel like they’ve been robbed of a brain trust.

Boston and other U.S. cities have long prided themselves on attracting the world’s best and brightest. Many have been immigrants, and over the past half-century, their work has contributed to numerous Nobel Prizes.

But the ban and the legal tussles it has touched off have cloaked all that in uncertainty.

Another Harvard researcher, Soumya Raychaudhuri, is also awaiting the fate of a new hire, Samira Asgari.

Asgari, also Iranian, said last weekend that she was not allowed to board a flight in Switzerland bound for her new job in Boston because of the ban — even though she already had a J-1 visa allowing her to work in the U.S.

“It’s a major setback,” Raychaudhuri said. “She has expertise in infectious disease, as well as expertise in computational approaches. That combination is very rare. To find someone with that skill set is really a challenge.”

“This is turning away the best and the brightest who want to come here, who see this as the land of opportunity,” Michel said. “America will become less great as a consequence of these policies. I’m not a politician, I’m a scientist.”