Chemistry.

No assembly required Using DNA as a scaffold, researchers devised a way of creating carbon-nanotube transistors that self-assemble in a test tube--a feat that paves the way for more-complex circuits made from these nanocomponents (164: 324).

Bone fix To serve as a scaffolding for the formation of new bone, a polymer material was adorned with proteins that stimulate bone regeneration and others that lead to the dismantling of the scaffolding as new bone tissue grows (163: 261 *).

Unnatural origins Bacteria and yeast cells were genetically engineered to incorporate an unnatural amino acid into their proteins, an advance that may lead to new drugs and shed light on the origin of the genetic code (163: 53; 164: 102).

Gecko tape Modeling the sticking properties of a geckos sole, researchers created an adhesive material that consists of arrays of microscopic plastic pegs (163: 356 *).

Miniature motor A gold plate centered on the shaft of a multiwalled carbon nanotube rotated when a voltage was applied, yielding a molecular-scale motor only 300 nanometers long (164: 54).

Perfect timing A biodegradable polymer microchip implanted under the skin could store and deliver multiple doses of medications at programmed intervals, eliminating the need for pills and injections (164: 260 *).

Danger detection In the wake of the Sept. 11, 2001 attacks, analytical chemists raced to develop portable sensors capable of detecting the barest whiff of a chemical or biological weapon (163: 362).

Plastic memories In pursuit of cheaper materials for permanently storing vast amounts of digital data, researchers fabricated a memory device out of electrically conducting plastic (164: 309).

Refueling rockets Experiments showed that paraffin wax might someday replace solid fuel in shuttle booster rockets, possibly becoming the cheapest, safest, and most environmentally friendly rocket fuel (163: 187 *).

Anemia begone A synthetic--and potentially more effective--version of the protein erythropoietin for treating anemia generated more red blood cells and lasted longer in the bloodstream than its natural counterpart does (163: 109).

Super threads Fibers made from carbon nanotubes mixed with an industrial polymer were 20 times as tough as steel wire and 17 times as tough as the Kevlar used in bulletproof vests (163: 372 *).

SUPERHYDROPHOBICITY

From polymers and carbon nanotubes, scientists fabricated self-cleaning materials dubbed superhydrophobic because water easily rolls off them and carries away dirt (163: 132 *; 164: 278).

[ILLUSTRATION OMITTED]

UNDERWATER BALANCING ACT

Microscopic crystals of aragonite located in the inner ears of zebrafish control balance and hearing. During development, special proteins guide the assembly of these crystals, called otoliths. When researchers dampened the activity of a gene that codes for one of these proteins, the otoliths switched from smooth round (top) to star-shaped (right) aragonite crystals. Silencing the gene entirely yielded chunky calcite crystals (bottom). Fish with modified otoliths became disorientated and swam in circles (164: 301).

[ILLUSTRATION OMITTED]

* An asterisk indicates that the text of the item is available free on SCIENCE NEWS ONLINE (http://sciencenews.org).