The best way to get rid of a cancerous tumor is to cut it out. But surgeons often leave behind a few cells, which allows the cancer to reemerge and spread. A team of researchers from Seattle Children's Hospital Research Institute and Fred Hutchinson Cancer Research Center may have a way to help surgeons more precisely eliminate all of the original cancer cells, by "painting" them with a protein derived from scorpions.

The scientists discovered that a protein called chlorotoxin, found in the venom of the deathstalker scorpion, binds to brain tumor cells minutes after it's injected. When combined with a fluorescent molecule, the protein lights up the cancer cells, allowing surgeons to see them in real time. This is particularly useful in brain tumors, where about 80% of cancers recur at the edges of the surgical site. The compound has been successfully tested in mice, and the scientists are preparing to seek Food & Drug Administration approval for human trials. Boeing (BA

) has teamed up with a handful of airlines to figure out how to make a jet engine that's efficient and environmentally friendly. Among the candidates for the biofuel that will power this engine: algae.

Turns out the green gunk that coats stagnant ponds and unkempt aquariums offers advantages over other efficient fuels, such as ethanol made from corn. Algae-based fuels may hold up better in the extreme temperatures, pressures, and weather conditions at which jets operate. What's more, algae is abundant and grows naturally, which should make it cheaper to harvest than crop-based fuels. Boeing is working on the project with New Zealand-based Aquaflow Bionomic and Air New Zealand.

Separately, Boeing is testing other types of biofuel with Virgin Atlantic Airways in an effort to convert an engine to run on clean fuel by 2008. A spokesman says one promising candidate is babassu, a Brazilian fruit similar to the coconut. Scientists at Technion-Israel Institute of Technology in Haifa, Israel, are creating traffic signals that may be smart enough to prevent car crashes. The team connected computers and cameras to "stop" and "yield" signs. When the cameras spot two cars approaching an intersection, the computer calculates the collision risk and then flashes warning lights on the sign to alert the drivers to slow down or stop. The system is currently being tested at two busy intersections in Tel Aviv, where limited visibility and high speeds make driving particularly hazardous, says David Mahalel, head of Technion's Transportation Research Institute.

The team's next goal is to invent a smart traffic light. When a driver doesn't stop at a red light, the system will delay the green light on the other side, so the offending driver can clear the intersection without causing a crash. The same technology might be able to spot and report drivers who violate traffic laws. -- One way to stop the spread of antibiotic-resistant bacteria is to interfere with their ability to procreate. A team of researchers at the University of North Carolina at Chapel Hill have found a way to do that, using drugs that treat bone loss from cancer and other diseases. The drugs, known as bisphosphonates, block a key enzyme, thus preventing E. coli bacteria from passing along the gene that makes them resistant to antibiotics. The scientists, who reported their discovery in a recent online edition of the Proceedings of the National Academy of Sciences, plan to test the drugs in other stubborn bugs, such as those that cause staph infections and pneumonia.

-- A fat-fighting drug might help kill tumors, too. Scientists at Wake Forest University School of Medicine in Winston-Salem, N.C., have discovered that the drug orlistat, known by the brand names Xenical and Alli, blocks a protein found in prostate cancer cells. That interaction causes the cancerous cells to die. The protein, described in the July 8 online edition of Nature Structural & Molecular Biology, is also active in other types of cancer.