The new chemical mineralogy instrument, called Chemin, weighs less than one
kilogram. It will use X-ray diffraction and fluorescence to provide an accurate
chemical fingerprint of Martian rock samples, allowing scientists to identify
with great precision what minerals they contain.

That identification has previously been lacking, notes Los Alamos geochemist
David Vaniman, as Martian rocks are quite complex, containing chlorine, sulphur
and water. “A lot of guessing games have been played about what the mineralogy
of the Martian surface is,” he says.

The device would be fitted to a rover similar to the Sojourner, which
explored the Martian landscape on the Pathfinder mission two years ago. But when
Chemin will be ready is far from certain. Vaniman and Bish say more development
work is needed before they can build an operational device fit to fly to
Mars—and this may take several years.

Called the MicroCAT, the scanner produces images at 10 times the resolution
available with conventional CAT scanners. It uses X-ray detectors that are only
50 micrometres square, producing images showing detail down to 100 micrometres,
according to Michael Paulus, who led the team that developed the system.
Typically, CAT scanners for human subjects have detectors that are 1 millimetre
square.

Researchers have used the prototype developed at Oak Ridge to examine the
internal organs and skeleton of sleeping mice that have a genetic mutation for
obesity. “We can now identify where the fat deposits are, how big they are and
how dense they are,” says Paulus. Until now, researchers have had to kill and
dissect the mice to assess the fat deposits, he says.

In a MicroCAT scanner for people, says Daniel Goldowitz, a neurobiologist at
the University of Tennessee in Memphis, “we could use it to look at embryonic
development to see if mutations cause gross maldevelopment.”

Heating biomass breaks it down into gases such as methane and carbon
monoxide. Traditional gasifiers generate the necessary heat by burning the
biomass in air. Unfortunately the nitrogen in air dilutes the gas produced. “The
gasifiers typically produce a gas with a heating value that’s only 4500
kilojoules per cubic metre,” says Robert Brown of the Center for Coal and the
Environment at Iowa State University in Ames. “That’s roughly an eighth of the
heating value of natural gas.”

By separating the burning and heating processes, Brown and his team have
produced gas with a heating value of 14 800 kilojoules per cubic metre. In the
prototype gasifier, which is a tube 0.5 metres in diameter and 2.5 metres tall,
the biomass is first burnt in air for about eight minutes. The heat from this
process is absorbed by metal ballast, which reaches temperatures of up to 760
°°ä.

Next, steam generated externally is forced into the cylinder to transfer the
heat from ballast to biomass. Cooling the mixture makes the steam condense,
leaving a gas rich in methane, hydrogen and carbon monoxide, but largely free of
nitrogen. Brown expects the final version to be just as good at producing gas as
other methods such as anaerobic digestion and fermentation.

Gary Staats, a fuel development specialist with the US Department of Energy,
says the simplicity of the gasifier boosts its appeal. “It’d be a real positive
[development] in reducing the cutting of trees to produce fuel,” he says. The
gasifier could be particularly useful in India, which produces enormous amounts
of bagasse, the fibrous residue left after sugar cane has been processed.

The system, which has been patented by a team from the Los Alamos National
Laboratory in New Mexico, has been built into material used for protective
clothing designed to shield against radiation, toxic chemicals or bio-hazards.
Knowing that they have been exposed to a hazard quickly will be a major
improvement for some workers. At present, tears that leave the wearer exposed to
the hazard may not be discovered for some time after they have occurred.

Some existing puncture detection systems either do not work in real time,
which means that they are only checked before protective clothing is donned.
Others only work when pierced by electrically conductive materials, such as
metal tools. The Los Alamos system, however, works when nonconductors such as
wood puncture the clothing. This gives it broader use, according to Robb Hermes,
one of its developers at Los Alamos.

The system is simplicity itself: a gooey, conducting material is made by
dissolving polyvinylalcohol and table salt (sodium chloride) in glycerol. Two
layers of the conducting polymer, each with an embedded electrode, are separated
by a nonconducting polymer. Two further layers of nonconducting polymer are then
added to the other sides of the conducting layers.

When there is a rip or puncture, the gooey conducting polymer layers are
forced through the insulating layer between them, closing a circuit. This could
be used to trigger a light emitting diode or audio alarm in the wearer’s face
mask.

Previous fabric warning systems used layers of thin metal foil separated by a
nonconductor. These systems only worked when they were pierced by a conductor.
The gooey polymer ensures that any tear will be registered.

“I wanted to make it as simple as possible so businesses would adopt it,”
says Hermes. Details of the wearer’s actual warning mechanism—sound or
light-emitting diode—have yet to be decided.

The polymer was originally developed for gloves built into the enclosed glove
boxes used by workers at Los Alamos to manipulate radioactive materials. The
gloves are replaced at regular intervals, but are not routinely tested,
according to Los Alamos spokesman James Danneskiold.

So if a glove is damaged, radioactive contamination is only detected after
the exposure has occurred, sometimes many hours later. With the new system, the
warning is immediate. This should ensure that workers stop using the gloves as
soon as they are damaged.

Psychologists Steven Shelton, Ned Kalin and their colleagues at the University of Wisconsin in Madison, exposed 13 female and 15 male monkeys aged seven-and-a-half months to fear-inducing situations, such as an unfamiliar human entering the room when the monkey was alone. On average, first-born monkeys had significantly higher levels of cortisol, and some had as much as twice the levels measured in their later-born siblings. The monkeys with high cortisol levels would also freeze in one spot for up to four times as long as the others.

The researchers believe the mother plays a key role in this behaviour. But they aren’t sure whether the difference between siblings is caused by inexperience or conditions in the womb. “Either the mother’s level of experience in raising the infant or something that’s happening in the uterus between the first and the later pregnancies is very different, and that is changing the baby’s hormonal status,” suggests Kalin.

The idea of looking at the way birth order influences stress came from the discovery that infant rats who were closer to the placenta than their litter mates while in the uterus had higher levels of stress hormone throughout their lives—and more fearful temperaments. Shelton also noted that in monkeys, the first-time mothers themselves had higher cortisol levels than those who had had several babies.

First-born humans may be similarly affected, Shelton speculates, but he is cautious about jumping to conclusions: “That’s a huge step from where we are.” However, he points to findings in both humans and monkeys that chronically high levels of cortisol are associated with fearful and other negative behaviour.

Toni Falbo, a psychologist at the University of Texas in Austin, agrees that jumping from birth order and stress in monkeys to humans is a bit tricky. While it’s possible that parents of first-borns may be more anxious and may pass that on to their offspring, she cautions against drawing firm conclusions from the study. “I don’t know of any large-scale studies that have checked out the effects of stress level and birth order in humans,” she says. Besides, children are subject to many influences other than parental ones, she notes.

Ground penetrating radar cannot see through salt water and it has always been
assumed that the technique cannot be used anywhere near saltwater or in tidal
areas. But William Chadwick, a geologist at the University of Delaware,
discovered the dump on a small spit of land in a salty coastal marsh.

The water in the ground was fresh, confounding expectations, partly because
water extraction had not artificially lowered the water table, and Chadwick
could see signs of contrast with the radar—indicating differences in the
composition of the soil—as deep as 8 metres. Archaeologists had already
found ancient clams and other shells on the surface, so Chadwick knew there
might be a rubbish dump in the area. Although it has yet to be excavated,
archaeologists believe native Americans harvested shellfish at the site.

Lawrence Conyers, a University of Denver archaeologist and authority on
ground penetrating radar says many archaeologists tend to ignore modern
technology. “That’s the typical problem with any kind of high tech device like
this. People are stuck in their ways.”

Chadwick says that ground penetrating radar can be used anywhere in the tidal
range. Without it, he says, archaeologists would have begun digging in the wrong
place. “It’s a good noninvasive tool to help investigations,” says Chadwick.

Most military and commercial jets use a kerosene-rich fuel called JP-8 or Jet
A, which has always been considered safe. But scientists are now starting to
investigate the risks of breathing the aerosols of unburnt fuel that shoot into
the air when an aircraft starts its engines.

Mark Witten, a respiratory physiologist at the University of Arizona in
Tucson, has exposed rodents to aerosols of JP-8 containing droplets between 1.5
and 1.8 micrometres across—similar to those created by jet engines.

Even a single, hour-long exposure to an aerosol containing 50 milligrams of
JP-8 per cubic metre increased lung permeability in mice and caused the loss of
cilia, the hair-like projections that waft dirt out of bronchial tubes. “This
will allow dust, pollen and other stuff in the lungs to set up a chronic
inflammatory state,” says Witten.

Other researchers are studying the effects of repeated exposure to JP-8.
Carol Baldwin of the University of Arizona exposed five rats to aerosols
containing 1000 milligrams of JP-8 per cubic metre over five weeks. Each week,
they breathed the aerosol for an hour a day on five separate days. Finally, for
an hour a day on three further days they breathed an aerosol containing 2500
milligrams of fuel per cubic metre. The rats became hyperactive. In trials
lasting three minutes, they reared onto their hind legs an average of 17
times—more than twice as often as animals that had not breathed JP-8.

The animals had previously learnt the location of a platform submerged in a
tank of water. After exposure to JP-8, they had forgotten where to find it. But
they could learn new tasks, which suggests that the fuel had specific effects on
memory—perhaps by interfering with a brain region called the
hippocampus.

Meanwhile, Steven Kornguth of the University of Wisconsin, Madison, has
exposed mice to aerosols containing 1000 or 2500 milligrams of JP-8 per cubic
metre for an hour a day over one week. Compared to control animals, their
retinas and cerebellums contained up to five times as much glutathione
S-transferase, an enzyme that detoxifies many harmful substances. This raises
the possibility that JP-8 could disrupt vision and proprioception—the
sense of where one’s body is in space.

The exposures studied by Baldwin and Kornguth may be higher than those
experienced by aircraft ground crews. But until detailed studies on ground crews
are carried out, no one knows for sure.

David Leith, an environmental engineer at the University of North Carolina
School of Public Health in Chapel Hill, is now developing instruments to measure
the density of JP-8 aerosols. In a trial in Alaska, the plume created by a jet
exceeded 200 milligrams per cubic metre of JP-8—the maximum his device
could register.

So far, most evidence of the health effects of JP-8 on ground crews is
anecdotal. “I talked to crew chiefs, and they said they seem to have more colds,
more bronchitis, more chronic coughs than the people not exposed to jet fuel,”
says Witten.

At next week’s meeting, sponsored by the US Air Force, the Environmental
Protection Agency and the National Institute of Occupational Safety and Health,
officials hope to lay down a plan for future epidemiological studies.

“What we’re trying to do is develop exposure standards for anyone who works
around an aircraft,” says Major Les Smith of the Brooks Air Force Base in San
Antonio, who chairs an Air Force committee looking at the health and
environmental effects of JP-8.

But Joshua Otaigbe, a materials scientist at Iowa State University in Ames,
has found that mixing the soya-bean protein with polyphosphate fillers and
silane produces a more durable and water-resistant plastic.

“The polyphosphate fillers increase the stiffness and strength of
soya-protein plastic,” he says. “They are also able to reduce the water
absorbency.” The silane retards water absorbency as well, and helps the
polyphosphate to bind with the soya-protein plastic.

In laboratory tests, the modified plastics have survived more than a year
underwater. The unmodified plastic dissolved in a few hours.

Otaigbe is now testing the soya-based plastics in soil to see how well they
degrade. He expects the materials to be useful in a variety of roles, from food
packaging to medical sutures. They may even turn up on the golf course as tees.
“After you finish your round of golf you can throw them away to biodegrade in
the environment,” he says.

The plastics will be relatively cheap, Otaigbe says, because soya beans are a
renewable resource. The crop is grown extensively in Iowa and neighbouring
states in the Midwest.

The Swept Frequency Acoustic Interferometer measures four characteristics of
an unknown chemical to paint a unique portrait of it. It can then tell
investigators or emergency personnel what they might be dealing with. “All
chemicals have various physical properties,” says the device’s developer, Dipen
Sinha, a physicist at Los Alamos National Laboratory. “It’ll be very rare that
two materials will be identical in these properties.”

The interferometer first checks the sample’s density and then the speed at
which sound will pass through it. Next it monitors the overall attenuation of
sound on its way through the sample and finally it measures the different levels
of sound attenuation at specific frequencies.

The detector, which weighs less than 3 kilograms, emits a signal sweeping
from 1 megahertz up to 15 megahertz. Sinha says the high frequencies act like a
pencil beam. “They can penetrate through the container wall,” he says. The
pulses do not need to be powerful, however—the device emits less than 1
milliwatt of sound.

The detector compares the profile of the suspect chemical with an internal
database until it finds a match. The nerve gas attack on the Tokyo underground
in March 1995 focused attention on the danger of chemical weapons. The present
database concentrates on these weapons, says Sinha.

He has entered profiles for all the known agents, such as sarin and mustard
gas, into the database. “If a new one comes along, all I have to do is update
it,” he says. Sinha says he is currently gathering data to allow the
interferometer to identify explosives.