Science Notes

Move Over, Mr. Clean

Carbon dioxide, the gas that puts the fizz in soda pop, soon may find a more socially redeeming use: as a "green" industrial cleaner.

For years, researchers have tinkered with the idea of using CO2 to scrub everything from computer chips to sport coats. By squeezing it sufficiently, the gas becomes liquid. At slightly lower pressures, it goes "supercritical," displaying liquid-like properties. Either way, it's abundant, cheap, plants love it, and when you're finished with it, you just ease the pressure and vent it.

The problem? Nothing dissolves in liquid CO2, so it can't break down and carry off grease, oil, or any other component of the 15 million tons of solvents industry uses worldwide each year.

Until now. A US-Italian research team, based at the University of North Carolina at Chapel Hill, has developed a compound that when added to supercritical CO2, allows the fluid-like gas to dissolve polystyrene particles from off a test plate. The additives, the researchers say, can be tailored for the particular cleaning job at hand. They've devised these additives, or surfactants, to deal with a variety of compounds other than polystyrene. Their work appears in the current issue of the journal Science.

Roots uncovered

Those pesky dandelions and the grass in your lawn share more than living space. They represent two groups of plants that sprang from a common ancestor some 130 million to 200 million years ago, according to a new study by researchers at Texas A&M University at College Park.

Moreover, the scientists say, the genetic similarities they've discovered between the two groups could give breeders a wider variety of genetic material to use to develop new or hardier plant varieties. The research team compared the genetic makeup of four plants, ranging from Aradopsis, a mustard plant, to broccoli, cotton, and sorghum.