BNL's Panayotis (Peter) Thanos

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 Number 193

September 26, 2005 

System drastically cuts down botulism detection time

One of the most lethal substances in the world botulinum neurotoxin, which  causes botulism is traditionally detected using mouse bioassays or "enzyme-linked immunosorbent assays," which typically require days or hours respectively to obtain a result.  Now, researchers at PNNL have developed a method for detecting its presence in as little as five minutes, using the Lab's successful Biodetection Enabling Analyte Delivery System, or BEADS combined with optical detection.  The detection system includes two critical features. First, BEADS isolates the toxin from environmental samples using antibodies to purify and concentrate the toxin to enable accurate and sensitive detection. Next, a second antibody, called a reporter antibody, labeled with a fluorescent dye or a fluorescent quantum dot binds to a different region on the toxin. The fluorescence of the quantum dot is measured on the bead and can quantify the concentration of the toxin.  In addition to detecting botulinum toxin, the system can be tailored to detect multiple pathogens or toxins, such as E. coli, salmonella, and ricin, simultaneously.

[Greg Koller, 509/372-4864,]

PPPL provides small plasma lab to Goshen College

A small plasma lab soon will be on its way from the U.S. Department of Energy's Princeton Plasma Physics Laboratory (PPPL) to Indiana to serve as a teaching tool for undergraduate students at Goshen College. The lab uses helium and neon plasmas and consists of two glass plasma-filled tubes. It is designed to teach students some plasma physics and give them experience with vacuum systems, basic electrical measurements, optical measurements and spectroscopy, plasma diagnostic techniques, and data analysis. It also will allow for creativity and the design of new experiments. The equipment is expected to be operational at Goshen in time for the January 2006 semester.

[Anthony DeMeo, 609/243-2755,]

New beam lines handle SPEAR3 thrust

Close-up of SPEAR3. (Photo by Peter Ginter)
Close-up of SPEAR3.
(Photo by Peter Ginter)

Three beam lines on the SPEAR3 accelerator at the Stanford Linear Accelerator Center are undergoing major upgrades during the machine's scheduled downtime that started August 1 and ends November 28. When complete, the beam lines will be ready to handle the fivefold increase in beam power—to 500 milliamps (mA)—that SPEAR3 began generating on June 20. The beam lines will shine light for macromolecular crystallography, biological x-ray absorption spectroscopy and hard x-ray materials science applications. SSRL currently has 11 beam lines. A typical beam line carries the synchrotron x-rays created by magnets on the SPEAR3 storage ring some 30 to 35 meters to experimental stations where the research is done.

[Heather Rock Woods, 650/926-2605,]

Tiny devices eliminate blood drawing for medical tests

Jeb Flemming, project lead for the ElectroNeedle platform, holds a test version.
Jeb Flemming, project lead for the ElectroNeedle platform, holds a test version.

Two tiny devices recently developed by researchers at DOE's Sandia National Laboratories could mean the elimination of blood drawing by diabetes patients to test glucose levels or by medical personnel to determine if someone is having a heart attack.

The two arrays of micron-sized needles operate similarly by penetrating painlessly into the skin. Arranged in varying numbers on a small patch, the needles can measure molecules inside the body, eliminating the need to withdraw blood from a patient.

One device is ElectroNeedles, micron-sized electrodes capable of measuring molecules such as glucose that can donate or accept electrons. The other is µPosts, micron-sized posts that have the potential of painlessly measuring proteins and other macromolecules, released during a heart attack.

The platforms complement each other and together create a diagnostic suite capable of detecting many important biological markers. Because the analysis is done inside the body, the need to withdraw body fluid is eliminated, and the needles are so small, the measurements are painless.

[Howard Kercheval, 505/844-7842,]


Turning off alcohol abuse

Panayotis (Peter) Thanos
Panayotis (Peter) Thanos

“Stopping alcohol abuse will never be as easy as turning on or off a ‘switch,'” says Panayotis (Peter) Thanos, a neuroscientist at the U.S. Department of Energy's (DOE's) Brookhaven National Laboratory . “But understanding the brain's reward circuits and finding ways to modulate them could play a role in developing successful treatments.”

Through brain-imaging and behavioral studies in animals, Thanos and his colleagues have demonstrated that a variety of brain receptors play a role in excessive drinking — including those for dopamine, one of the brain's primary reward chemicals, and those that trigger the reinforcing properties of marijuana.

Adding more receptors via “ gene therapy” or blocking their ability to send pleasure/reward signals can drastically affect drinking behavior, Thanos' studies have shown.

“When you see a rat that chooses to drink 80 to 90 percent of its daily fluid as alcohol, and then three days later it's down to 20 percent, that's a dramatic drop in alcohol intake.”

Thanos traces his interest in brain chemistry and behavior to an undergraduate class at Queen's University in Canada. He volunteered to work with his professor in the lab and got hooked — on research. After completing his Ph.D. at Eastern Virginia Medical School, he went to Stony Brook University and collaborated with scientists at Brookhaven's Center for Translational Neuroimaging, joining the Lab as a neuroscientist in 1999.

Thanos extends the research opportunity he had as a student to three or four undergraduate students each semester — and sometimes more in the summer. “Even if students have had no prior research experience,” he says, “they can produce great work.”

With many of these students going on to medical school, graduate school, dental and veterinary schools, it's clear that Thanos' ability to spot and spark that motivation pays off for the students as well as their mentor.

Submitted by DOE's Brookhaven National Laboratory


Check out symmetry—the
particle physics magazine from
Fermilab and SLAC.


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Meteoroid ‘smoke' may influence weather, study finds

This image of a dust cloud from an asteroid plunging into Earth’s atmosphere shows some of its unusual properties. The cloud sits vertically with thin wispy layers separated by a few kilometers. It lasted about an hour.
This image of a dust cloud from an asteroid plunging into Earth's atmosphere shows some of its unusual properties. The cloud sits vertically with thin wispy layers separated by a few kilometers. It lasted about an hour.

Space-based infrared sensors of the U.S. Department of Defense detected the object 75 kilometers high, descending rapidly off the coast of Antarctica.

DOE visible-light sensors, built by DOE's Sandia National Laboratories, noticed the intruder when it became a fireball. They identified it as an asteroid — not a missile — 56 kilometers above Earth. Five infrasound stations, to detect nuclear explosions anywhere in the world, registered acoustic waves (analyzed at the DOE's Los Alamos National Laboratory), confirming the speeding asteroid.

The debris cloud formed by the disintegrating space rock was imaged by NASA's multi-spectral polar orbiting sensor.

This array of multi-agency sensors worked together to provide basic facts: the time of entry, speed, and size — one of the largest meteoroids to enter Earth's atmosphere in a decade.

But, there was one last sighting: scientists using ground-based lidar detected an irregular cloud of material in the upper stratosphere over Antarctica. These were the first direct measurements of meteoritic “smoke.”

Scientists have paid little attention to meteoroid dust, assuming it did not affect Earth's environment, says Andrew Klekociuk, a scientist at the Australian Antarctic Division. New observations suggest that this micron-sized dust could play a more important climate role, according to Klekociuk and other researchers, including Sandia's Dick Spalding, in an Aug. 25 paper published in the journal Nature.

The asteroid deposited 1,000 metric tons in the stratosphere in seconds, according to data from Sandia sensors, whose primary function is to detect nuclear explosions. The sensor evolution to include meteor fireball observations came when Sandia's Spalding recognized that ground-based data processing might be modified to record the relatively slower flashes of asteroids and meteoroids.

This ability to distinguish a nuclear explosion from an asteroid fireball with equavalent energy provides an additional safety margin for decision makers responding to nuclear threats.

Submitted by DOE's Sandia National Laboratories

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