Tiny "smart dust" particles can detect biological and chemical agents like anthrax or sarin dissolved in drinking water or floating in the air.

The micron-sized chips could be inconspicuously stuck to paint on a wall or dispersed into a cloud of gas, changing color if one of thousands of chemicals is present, said Michael J. Sailor, a professor who headed the research effort.

Using silicon chips and parts from an inexpensive compact disc player, Sailor's lab also developed a portable detector that can detect explosives and nerve gas.

Meanwhile, engineers at the university's San Diego campus are using techniques developed to retrofit buildings for earthquakes to protect the U.S. embassy in Greece and other structures from bomb blasts.

Thin composite overlays made of carbon fibers can be applied like wallpaper to walls, floors or columns. Blast tests conducted on a five-story building at the White Sands Missile Range in New Mexico showed that the materials help buildings avoid collapse.

The fibers can also wrapped around steel bridge cables, such as those at the Golden Gate, to prevent them from snapping in a terrorist attack, said Frieder Seible of the Jacobs School of Engineering.

- Seth Hettena, AP writer.

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TUCSON, Ariz. -- Take a closer look next time you drive past a palm tree, a grain silo or a water tower. That might be a camouflaged cell phone tower you're seeing.

And that penthouse facade atop a downtown city building? Or a saguaro cactus in Arizona? Them, too.

It's just the latest fabricating wizardry from Larson Co., which pioneered realistically looking artificial rock formations, animal habitats and seascapes a quarter century ago for zoos, museums, parks and aquariums.

Larson produced its first camouflaged and trademarked Tree Pole in 1992 for a wireless carrier.

It has since built about 300 "tree" towers and other structures to conceal cellular antennas.

Competition has pushed carriers to dramatically increase their capacity, yet communities routinely ban ugly cellular towers as visual pollution. That's produced a greater need for the faux towers, which sell for $20,000 to more than $100,000, said Andrew Messing, the company's president and chief executive.

Tower Ventures of Memphis, Tenn. is one customer.

One 130-foot-tall Larson-camouflaged pine tree bristles with antennas for six cellular carriers. Tree branches made of fiberglass disguise the antennas without degrading their signals.

"We're very happy," Tower Ventures owner Billy Orgel said. "They do nice work."

- Arthur H. Rotstein, AP writer.

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SAN FRANCISCO -- In the nimble hands of today's youth, Nintendo's GameBoy, with its flashy graphics and sounds, rules the world of pocket-sized entertainment.

But there was a simpler time for handheld games, and Barbara Levine has the collection to prove it.

Her cache of some 250 palm-sized games are on display at the San Francisco Main Library in a new exhibit, "In The Palm of Your Hand: Dexterity Games 1880-1960."

For the past 20 years, Levine has scoured garage sales and antique stores to amass a trove of dexterity games from other eras.

The games, placed in doctor's waiting rooms or handed out in movie lines, require the player to maneuver one or more tiny metal balls into recessed holes.

Levine's machines include "Pigs in Clover," "Ringtail Cat" and "Silver Bullet." On these small cardboard and wooden devices, gentle taps of the finger and the subtle roll of the wrist reign supreme.

Levine herself is horrible at the games, she readily admits. She likes the escapism each game's theme offers into a simple but artful environment.

"I love them because they are imaginary worlds," Levine said, gazing at a small, box-shaped game called "Consult El Caro," that dates to 1918.

The player asks a question - "Oh El Caro! When will I find love?" Levine intones - and then moves the box in a figure eight until a small metal ball rests in one of several recessed holes containing an answer.

- Ron Harris, AP writer