As long as humans have been traveling into space, astronauts have experienced significant health effects from the extreme conditions of space flight, notably the reduction of gravity.

Two Buck scientists led a team that has revealed for the first time how the lack of gravity affects the cells of the immune system at single cell resolution. The co-senior authors, along with Christopher E. Mason, Ph.D. of Weill Cornell Medical College, Associate Professor David Furman, Ph.D. and Associate Professor Daniel Winer, MD, have published an extensive survey of how gravity affects immune cells, and the identification of "space nutraceuticals" to counter aberrant effects of microgravity on these cells. The work is published in Nature Communications

"We show how simulated microgravity shapes immune cells and how the changes in force alter the cells' function at the single cell level," said Winer. "This level of resolution is new and exciting in understanding the effects of microgravity on cells."

Using cells in simulated microgravity, combined with data from space flight from astronauts and mice on the International Space Station, the researchers created a complete picture of how the different cells of the immune system in the peripheral blood are shaped by reduced gravity.

China on Tuesday announced the first astronaut candidates from its special administrative regions of Macau and Hong Kong, with the latter calling it a "glorious page" in the city's history.

Beijing has invested billions of dollars in its military-run space program as it pursues ambitious plans for a manned lunar landing by 2030.

The China Manned Space Agency said Tuesday that a payload specialist from Hong Kong and another from Macau were among 10 candidates for the country's fourth batch of astronauts.

Hong Kong leader John Lee called it "a glorious page in Hong Kong's history".

"This is... the first time that a Hong Kong citizen was selected as a payload specialist in China's manned space program, with a chance to become an astronaut to go to space in person, to participate in research and to contribute the country's space program," Lee said.

Sun Dong, Hong Kong's tech and innovation secretary, said the winning candidate was selected out of a pool of 120 applicants through a multi-round process that has been going on since 2022.

"We accepted a rather wide range of professional backgrounds including natural sciences, engineering, biology and medical science, because the space is a brand new area for scientific exploration," he told reporters, declining to name the Hong Konger selected.