Scientists at the Goddard Space Flight Center in Greenbelt,Maryland, found the substance glycine in material brought back to Earth from a comet.

VOA: special.2009.09.30

He made everything - except coffee - from sourdough, a substance used in making sourdough bread.

VOA: special.2009.01.24

Cells in the airways begin to produce too much of a thick, sticky substance called mucous.

VOA: special.2009.07.28

Later,Mizz Blackburn and Mizz Greider discovered the substance in the body that builds telomeres.

VOA: special.2009.10.07

Ultraviolet light from the sun changes a substance in the skin into vitamin D.

VOA: special.2009.04.21

Later,it became the active substance in a medicine that Bayer called aspirin.

VOA: special.2009.10.20

It is also needed to make a light-sensitive substance in the eyes.

VOA: special.2009.04.21

He was studying a substance in the hull that covers rice.

VOA: special.2009.04.21

The competition includes acetaminophen, the active substance in products like Tylenol.

VOA: special.2010.12.14

The substance is used in toothpaste and medicine for stomach problems.

VOA: special.2009.08.25

Scientific eExpert in WHO's Mental Health and Substance Abuse Department, Alexandra Fleischmann says risk factors vary in different cultures.

VOA: standard.2009.09.10