An element is a chemical substance made up of a particular kind of atom and hence cannot be broken down or transformed by a chemical reaction into a different element, though it can be transmuted into another element through a nuclear reaction.
Almost 40 years separate Shirley Ann Jackson's achievement, as the first African-American woman to earn a Ph.D. in theoretical high energy physics at Massachusetts Institute of Technology, and Jedidah Isler, the first African-American woman to receive a Ph.D. in Astrophysics from Yale.
Dr. Rebecca Crumpler was the first African American woman to earn an M.D. degree. Rebecca Lee Crumpler challenged the prejudice that prevented African Americans from pursuing careers in medicine to became the first African American woman in the United States to earn an M.D. degree, a distinction formerly credited to Rebecca Cole.