NYT's Science and Environment (Video)

Anne Kornhauser had the front half of her foot amputated after being diagnosed with cancer, but the artificial foot she received left her in constant pain.

Michael La Forgia lost the toes of his left foot and the toes, heal and the arch of his right foot after a bout with bacterial meningitis.

Amy Palmiero-Winters, an avid marathon runner, lost her foot in a motorcycle accident.

Seun Adebiyi — an Olympic hopeful, Yale Law School graduate and leukemia survivor — is trying to start a public cord-blood bank in Nigeria.

Gretchen Reynolds, the Phys Ed columnist, on the science of high-intensity interval training, or H.I.T., which scientists are finding can be as effective as longer endurance training.

Michael French has frontotemporal dementia, for which there is no cure or treatment. As his condition deteriorated, his wife, Ruth, had to move him to a nursing home, where she spends most days.

A video interview with the Harvard cognitive psychologist on babies and the nature of human knowledge.

Wireless companies say that smartphones are threatening to overwhelm their networks, and are asking the government for help. But some experts maintain that technology already has the answers.

At current growth rates, sub-Saharan Africa, which now makes up 12 percent of the world’s population, will account for more than a third by 2100.

Suleika Jaouad, a writer and recent college graduate, is chronicling her experiences as a young adult with cancer in a new weekly column.