Human blood contains stem cells that can be transformed outside the body into a variety of cell types, suggesting that a person's blood could someday provide replacement cells for that individual's damaged brain or kidney. (p. 131)

Two new fossil discoveries have fueled scientific debates about the evolutionary status of a pair of species traditionally considered to have been our direct ancestors, Homo habilis and Homo erectus. (p. 131)

Oxygen deprivation—an escalating problem in freshwater ecosystems worldwide—tampers with sex hormones in carp and might underlie the decline in some fish and amphibian species. (p. 132)

Researchers have produced new types of water-repelling surfaces, including one that's colorful and another made of inexpensive plastic. (p. 132)

In its first large test, an AIDS vaccine has failed to shield an at-risk population from acquiring AIDS. (p. 133)

Lab experiments show that the burning of peat from coastal areas of Scotland could be responsible for the enigmatic concentrations of dioxins sometimes found in pre-20th-century soils. (p. 134)

A rare before-and-after study of a takeover by an invasive ant species shows the interloper quickly disassembling the basic rules of the invaded community. (p. 134)

After chronicling space science and exploration for 3 decades on behalf of Science News, Jonathan Eberhart died last week from complications of multiple sclerosis. (p. 134)

A home-based technique for treating microbe-contaminated water with chlorine solution could save millions of lives in countries that are currently unable to provide residents with safe drinking water. (p. 136)

Some galaxies were in place and forming stars at a prolific rate when the universe, now 13.7 billion years old, was just an 800-million-year-old whippersnapper. (p. 139)

Silk cocoons could become puffs of valuable human proteins if a new bioengineering method pans out. (p. 141)

Scientists have developed a synthetic antioxidant that won't, at high doses, foster the tissue damage the compounds are meant to prevent. (p. 141)

The ceramic titanium silicon carbide can fully recover after being compressed to a degree that would leave most ceramics shattered and most metals permanently deformed. (p. 141)

Dolly, the first clone of an adult mammal, has been euthanized after acquiring a severe lung infection. (p. 141)

Using strips of synthetic RNA that interfere with normal gene action, scientists working with mice have stopped the progression of hepatitis. (p. 142)

HIV-positive women who receive the drug nevirapine during pregnancy often have HIV that is resistant to the drug in their breast milk after they give birth. (p. 142)

Men with exceptionally sensitive powers of taste may face extra health risks, such as colon cancer. (p. 142)

A plastic material used in some biological implants could someday form a foundation for tissue that can repair or replace human vocal cords. (p. 142)