Both Web sites come from Science@NASA, an online source for news and information about NASA-funded research. The first article describes the work of researchers at the Center for Commercial Applications of Combustion in Space, who are developing artificial bones for long-lasting, pain-free hip and knee replacements. These ceramic bones are touted as "so much like the real thing that they could actually meld with living bone." Earlier this year, researchers at the Space Vacuum Epitaxy Center in Houston experimented with "photosensitive ceramic films that respond to light much as rods and cones do," the subject of the second Web site. Researchers hope these films will eventually be used to restore lost vision in human eyes. Each article is available as an audio file, and includes helpful diagrams and Web links for related articles and information.