POLYMERS GIVE NEW LIFE TO THE NERVOUS SYSTEM

Nerve damage is difficult to repair because once a nerve is severed its cells don't regenerate themselves easily. Nerve cells cannot reconnect beyond a gap wider than a centimeter. Eventually, that part of the neuron "downstream" from the wound dies. "Peripheral nervous system axons—the part of the nerve cell that carries the impulses—normally have a connective tissue sheath of myelin to guide their growth. And without that guidance, they aren't able to grow productively," explains Surya Mallapragada, a professor of chemical engineering at Iowa State University and an associate in materials chemistry at the U.S. Department of Energy's Ames Laboratory. She has developed a method of using superthin, biocompatible, and biodegradable polymer films to help nerve cells re-grow properly. Mallapragada and her team use films only a few hundred microns thick, much thinner than a human hair. They then etch patterns onto the film, and these patterns guide the regenerating cells. They've devised two methods to do this. A "casting" technique first etches the patterns onto a silicon wafer, which is then imprinted onto the film. "We also use a direct etching method using lasers and atomic-force microscopy," she says. The latter method is slower but gives the researchers more flexibility.

In recent trials, tiny bits of rats' sciatic nerves were sliced away. The damaged nerves were then spliced together using the film. The rats began showing movement in their legs after three weeks and were functioning normally after six weeks. "We're essentially mimicking what nature does," Mallapragada says. Now that they've proved it works on the peripheral nervous system, she and her colleagues are turning their attention to the central nervous system, specifically trying the procedure on rats' optic nerves. In these tests they are trying to further promote nerve-cell growth by the addition of adult stem cells. The commercial polymers needed for this treatment is relatively costly, she admits, but not prohibitively so.

 

DETECTING DANGER

Tiny antennas of silver may prove to be extremely powerful tools for detecting chemical and biological agents. Research at Purdue University directed by electrical engineering professor Vladimir Shalaev is demonstrating that arrays of these microscopic antennas are much more sensitive than detectors now in use. Each antenna is a mere 10 nanometers wide, a fraction of the width of a human hair, and is composed of links of silver particles. Arranged in self-repeating patterns, or fractals, the nanoantennas can be tuned to respond to thousands of different molecules. The signal each antenna receives is amplified by as much as 100,000 times by plasmons, masses of electrons that cover the surface of the nanoantennas. And these enhanced signals are transmitted to a receiver. In the lab, a thin, metal film is coated with the nanoantennas and pressed between glass substrates. Shalaev says he and his team are not yet at the stage of designing practical sensors, but he says that strips of the film could be submerged into water to check for toxic agents in water supplies or placed on walls to detect agents in the atmosphere. "We are still trying to understand the fundamental science," Shalaev says, "but we are close to the time for thinking of practical applications."

 

American highways are dangerous and deadly. In 2001, nearly 38,000 people were killed and 2 million injured in road accidents, according to the U.S. Department of Transportation. Now, University of Florida researchers want to use radar technology to make our highways safer. They're recommending the use of "smart beacons" implanted along roadsides at every 100 feet to warn drivers of impending dangers, like accidents or fog-related snarls. The beacons would flash either yellow or red to warn drivers to slow or stop; otherwise they'll glow green. They would be about the size of a pack of playing cards and contain solar cells for electricity, batteries, lights, radar, and wireless communications electronics. The beacons would use ultrawideband radar (UWB), the same system that automakers want to use for onboard collision-avoidance mechanisms.

The beacons would not require human intervention, although law or rescue personnel could control them remotely in order to mark evacuation routes or detour traffic around accidents. "The sensors will automatically determine if a crash has occurred. They'll then transmit that information to sensors a mile or two up the road, warning drivers that they haven't yet reached the crash site," explains Dave Bloomquist, an associate professor of civil engineering at the University of Florida. UWB broadcasts rely on split-second pulses of radio energy that can be measured to precisely determine the location of objects and their speed. Bloomquist says the team wants to have a prototype system built and installed within 18 months. They reckon each beacon will cost about $30—not so cheap. But if the system helps to save lives, it may prove invaluable.

 

HELPING HANDS

AUSTRALIA—Gloves are in vogue. But these latest creations would be more at home in an engineering research lab than on the catwalk. They come not from fashion designers but from engineers involved in two unrelated Australian projects. One helps deaf-blind people to communicate with each other while the other aids muscle repair.

Design engineer Peter Hvala, a Ph.D. student at Melbourne's Swinburne University of Technology, says his idea was sparked by a TV film in which people who are both deaf and blind explained their communication difficulties and a system of palm-touching called deaf-blind finger-spelling. "In the documentary a woman described how, when she lets go of the hand of the person with whom she's communicating, they could be 1,000 miles apart," Hvala recalled. "It made sense that there's a need for a device to emulate the second person."

He acknowledges that deaf-blind people use a wide variety of communication techniques. Those with some vision can access e-mail, others use Braille keypads—but many deaf-blind people depend on tactile communication. Hvala's glove allows people to use finger-spelling to construct words as if they are touching the person with whom they are communicating—except these words are transmitted in much the same way as cellular telephone text messages. Users must connect to a cell phone number. The recipient receives the message as a series of vibrating "touches" through a glove identical to that worn by the sender. According to Hvala, existing prototype devices work well, but some fine-tuning is needed. The university is talking to companies about the inventions.

The other down-under glove resulted from a collaboration between the Intelligent Polymer Research Institute at Wollongong University and Sydney's Royal North Shore Hospital, a major teaching facility. The research group devised a glove to stimulate muscle movement that will be useful for patients after hand surgery, spinal cord injury, burns, and strokes or for those who suffer from arthritis.

The hospital worked with the university where engineers Gordon Wallace, director of the Polymer Institute, and his colleague Geoff Spinks led a team that developed a glove containing plastic materials that store and conduct electricity. These polymers are stimulated by an electric current and "used in conjunction with fabric, liquids, and metals," Wallace said. "Most polymers are inert and very good insulators, but the structure of these particular materials is such that they can conduct electricity.

" They have unique qualities. When you inject a small amount of (electric) charge they can expand or contract quite dramatically, and that's the basis of the artificial muscle application. They're lightweight so you can get results using very small currents." Negotiations are also taking place for commercial development of this device, which exists in prototype form.

 

A BEE IN HIS BONNET

As a child growing up in Baldwin, N.Y., James McLurkin had two abiding interests: technology and biology, the former instilled by his parents' love of nature. While still in high school, McLurkin, now 30, had pro-grammed video games, assembled a customized computer, and conceived and built two robots. Now the Massachusetts Institute of Technology graduate student is leading a group of scientists at iRobot in Somerville, Mass. that's built more than 100 small robots—each about 4½ inches per side—that are programmed to mimic bee behavior. Swarms of these robots will cluster, disperse, follow, and orbit, thanks to algorithms he's developed. The invention of these self-contained, autonomous robots garnered McLurkin the ninth $30,000 Lemelson-MIT Student Prize for inventiveness. His bee ‘bots have bump and light sensors, a self-charger, a radio modem, and an audio system. He's working on giving them sensors to detect food and trails, as well as a camera. McLurkin, who is completing a Ph.D. in computer science, says that by having his robots interact like bees, they can complete individual tasks that support the group's collective goal. McLurkin has been buggy for quite some time—as an MIT undergraduate, he built smaller robots that simulated the behavior of an ant colony.

McLurkin believes that microrobotics must be linked to natural phenomena. His lab robots are for research and have no real tasks to perform, but he says whatever one robot can do well, a group of them can do better. Potential uses include searching for survivors in disaster areas, exploring caves and other dangerous venues, perhaps someday exploring planets. "As robot technology advances, so will swarm technology and software," McLurkin says.

Swarms of "evil" microrobots that threaten the world are the premise of Michael Crichton's best-selling recent book, Prey. McLurkin hasn't read it but doesn't think people should feel threatened by his work. "Anyone who has worked with robots knows how profoundly stupid they are. It's hard to get them to do anything, let alone take over the world." Well, that's a relief.

 

It would be wrong to say that Margaret Bourke-White's industrial photographs of are works that only an engineer could appreciate. The beauty of her art is accessible to all, but many of her pre-war photos are portraits that engineers might especially enjoy. Bourke-White had a long career and is particularly famous for her WWII images in Life magazine. But she first made her mark as a photographer of industry, and her photos helped create the original look of Fortune magazine, where many of them were featured. A new exhibit that focuses on her work from that era, "Margaret Bourke-White: The Photography of Design, 1927-1936," is at Washington's Phillips Collection through May 11 and will tour a number of venues across the country, including Sarasota, Fla., Charlotte, N.C., Fort Wayne, Ind., and Portland, Maine.

Bourke-White's father was an engineer and inventor who took her to a foundry when she was only 8. That began her lifelong fascination with machines. There are black-and-white images of smokestacks, furnaces, and dams, all shot from unusual and arresting angles. There are close-ups of stacks of bundled aluminum wire, boxes of freshly-milled nuts, gears, airplane propellers, and plow blades, all lit dramatically, as if they were fashion icons. Bourke-White, in addition to her Fortune work, also did commissioned photography for industry during this period, including advertisements and commemorative books. Humans are not often pictured in her shots, and they're usually dwarfed by machines when they are. She loved architecture, as well. And the show includes photos she took during the construction of New York's Chrysler Building. The exhibit also includes shots of industrializing Russia and Germany taken in the 1930s. Bourke-White showed the world that industrial design not only has utility but can be a thing of beauty.

 

BUILDING A GREENER BUSINESS

MONTREAL—It's not unusual for companies whose livelihood depends on the outdoors to talk about the importance of preserving the environment and the values of recycling and reusing. But Canada's Mountain Equipment Co-op goes one step further: It insists that its retail outlets conform to some of the most stringent environmental building standards anywhere. This May, the Vancouver-based company, which boasts 1.7 million members worldwide, will open a new store in Montreal. The $5.8-million building will be MEC's eighth across Canada and another product of its eight-year-old Green Building Program, which is designed to reduce the energy required both to build and operate its buildings.

At the Montreal store, geothermal heat supplied by earth-coupled heat pumps with 12 wells sunk 600 feet deep will provide the main source of heating and cooling, while solar panels will be used for heating water. Rainwater runoff from the building will be captured in an underground cistern and used for toilets and site irrigation. Plants that will decorate the site will be drought-resistant, indigenous species, requiring little maintenance. The 45,000-square-foot concrete and steel structure will even use salvaged building materials and new materials made from recycled content.

" I think there is a legitimate and straightforward connection between reducing our impact on the environment as a company and the requirements of the activities such as mountaineering and hiking that we support," says program manager Corin Flood. "Without wilderness or intact wild places, we can't get at our objective, which is to help people enjoy those places."

 

TOKYO—Like pet shops in the United States, the Tokyo-based Kojima pet store chain stocks the usual assortment of parakeets, gerbils, and chihuahuas. But in the warmer months it carries a seasonal creature, one of Japan's all-time favorite pets—large horned "stag beetles," known as kuwagata or kabuto-mushi. Collecting and raising the insects from larvae are as much a rite of summer here as fireworks and swimming pools. Boys especially love to show off the fearsome-looking, but harmless, pincers of their bugs or pit a couple of insects against each other, forcing them to duke it out with their oversized mandibles. Even grown-ups in Japan get misty-eyed over the giant beetles, which evoke lazy days poking around in the countryside rooting for prize insects.

Kojima stocks only cheap species costing a few dollars, but fanciers are known to pay thousands of dollars for a large, colorful, or particularly well-endowed prize bug. Police blotters record the occasional bug heist involving especially sought-after species. Japan's bug mania has spawned a brisk trade in imports from Taiwan and other Asian countries. But in recent years the surge in imports has led to an invasion of foreign-born, bug-attacking ticks. "It's up to our wholesalers to deal with the problem," says Kojima store manager Wataru Gokita. Still, he frets the tick plague could deplete local Japanese beetle species, on which the store depends, and lead to a run-up in bug sticker prices.

The apparently foreign ticks carry bacteria fatal to at least some of Japan's 50 beetle species. Japan's Environment Ministry is studying how to counter the invasion of the tick, part of an armada of exotic flora and fauna, but collectors fear import controls may come too late to save local beetles. At any rate, Japan's passion for beetles, along with the loss of forest habitat in the region, has raised concerns about the extinction of both domestic and other Asian species. Unlike whale tusks or exotic birds, fancy bugs are easy to smuggle and hence relatively attractive targets for illicit trade.

 

Air Force One is a national symbol, not unlike the White House, the Statue of Liberty, and Old Glory. As Kenneth T. Walsh writes, it's "one of the most distinctive icons in the world." With its bubble top, blue-and-white skinned fuselage-emblazoned with the words United States of America, AF One is recognizable almost anywhere in the world. Indeed, it's become a mainstay in Hollywood films; Harrison Ford even starred in a movie called "Air Force One." A new book, Air Force One: A History of the Presidents and Their Planes, written by Walsh—a longtime U.S. News & World Report White House correspondent, and a Prism columnist - charts the history of presidential aviation, which began in 1943 when Franklin D. Roosevelt boarded a PanAm prop plane, the Dixie Clipper, to fly to a secret meeting in Casablanca with British Prime Minister Winston Churchill to plot the Allied invasion of Europe.

Walsh's entertaining book focuses on the politics of presidential flight and the plane's place in history. Lyndon B. Johnson was aboard AF One when he was sworn in after the assassination of John F. Kennedy; Richard Nixon flew it to China; Ronald Reagan flew it to three groundbreaking summits with former Soviet leader Mikhail Gorbachev; Bill Clinton flew it more than any other commander in chief and liked to reward generous donors with rides. But the book also highlights in detail the triumph of the plane's engineering. Walsh quotes former Vice President Walter Mondale as noting that AF One is "an enormous symbol of American technological excellence." The current version—ordered in 1985 and built over a four-year period—is a souped-up Boeing 747, jammed with cutting-edge communications and security technology. It has four General Electric CF6-80C2B1 jet engines that can power it along at 700 miles per hour. AF One is covered in a special skin designed to deter electromagnetic impulses that could interfere with its communications or navigational systems. Also onboard is "a highly classified system of defensive countermeasures designed to ward off heat-seeking missiles." A second 747, dubbed the Doomsday Plane, often tails Air Force One, and it has special communications equipment and military hardware that would enable it to serve as a mobile command post "in a case of a catastrophic attack" on the United States. But given the upgrades accorded Air Force One over the years, some officials say the Doomsday Plane is no longer needed. Indeed, President George W. Bush proved how functional the presidential jet is as a high-flying Oval Office during the September 11 terror attacks, when he flew to several secure venues and monitored the situation while on board.

Today's Air Force One is a technological achievement, but it wasn't always so. After his Casablanca flight, FDR's next trips were aboard a Douglas C-54 dubbed the "Sacred Cow" by the press. His successor, Harry S. Truman used that plane too, but in 1946 took command of a DC-6 he called Independence. Dwight D. Eisenhower initially flew on three different versions of a Lockheed Constellation, also a prop plane. But he commissioned the first jet, a Boeing 707 that remained in use for three decades. It was that plane that eventually got christened Air Force One. Reagan OK'd construction of the 747 now in use, but it wasn't finished until his successor, George H. W. Bush, was in office. Walsh notes that this plane will likely stay aloft for another 20 years, but ultimately will be replaced by a supersonic aircraft. Whoever is the leader of the Free World in those years must be seen as keeping up with advances in aerospace engineering. Just imagine: presidential politicking that's faster than the speed of sound.