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April 2001

The Laboratory
in the News

Commentary by Bert Weinstein

A New Kind
of Biological
Research

The World's Most Accurate Lathe

Leading the
Attack on Cancer

Electronic Memory Goes High Rise

Patents

Awards


The Laboratory
in the News

Laser stroke treatment proven safe
The Endovascular Photo-Acoustic Recanalization (EPAR) laser system used to break up blood clots in the brain has been shown to be safe as a new treatment for stroke. The EPAR system, which is made by Endovasix Corp. of Belmont, California, was originally created by scientists at Lawrence Livermore in cooperation with Endovasix.
The device works by delivering laser energy in the form of an acoustic wave into a blood clot that is blocking the flow of blood in the brain. The laser beam reaches to the site of the clot via a catheter threaded through the body's blood veins.
EPAR was tested in a recently completed study involving 26 patients with severe stroke. The device was shown to be safe and to produce no major complications. Dr. Helmi L. Lutsep of the Oregon Stroke Center in Portland, Oregon, reported the finding of the safety study at the 26th International Stroke Conference of the American Heart Association in Fort Lauderdale, Florida. Lutsep also indicated that a multicenter trial of the laser treatment system's efficacy will begin soon.
Contact: Randall Elder (925) 422-9914 (elder3@llnl.gov).

Lab forensic work aids in arrest of "Angel of Death"
The Laboratory's Forensic Science Center and its director Brian Andresen were instrumental in the recent rearrest of Efren Saldivar, the self-proclaimed "Angel of Death" and alleged killer of terminally ill patients at a Glendale, California, hospital.
Special analyses by the center gave Glendale investigators evidence they could use to arrest Saldivar and charge him with the murders of six patients. Saldivar, a former respiratory therapist at Glendale Adventist Medical Center, was first arrested in 1998. He confessed to killing between 100 and 200 patients, whom he deemed "ready to die," by injecting two paralyzing drugs, Pavulon and succinylcholine chloride, into the patients' IVs. He later recanted and was released.
At the request of Michael Peat, then president of the American Academy of Forensic Sciences, Andresen traveled to southern California to assist in the autopsies of the exhumed remains of some of the "most mysterious" of the Glendale deaths. He prepared and demonstrated the proper sampling equipment for coroner's office personnel and, using a new scientific protocol, showed them how to retrieve and preserve evidence correctly.
Because succinylcholine chloride breaks down quickly into chemicals normally found in human tissue, Andresen concentrated on Pavulon, a potent, synthetic muscle relaxant often administered in low doses to patients on artificial respirators. He found 6 positive results for Pavulon out of 20 autopsies.
In early January, Saldivar was rearrested, based primarily on Andresen's findings.
For more information on Livermore’s Forensic Science Center, its accomplishments, and mission, visit the Web site at http://www.llnl.gov/IPandC/op96/10/10h-for.html.
Contact: Brian Andresen (925) 422-0903 (andresen1@llnl.gov).

Lab physicists’ revised theory of nebula formation
Scientists may be closer to understanding the formation of the famous Eagle Nebula, thanks to the recent simulations of Livermore physicists Jave Kane, Dmitri Ryutov, and Bruce Remington.
The nebula is located about 5,700 light years from Earth and is known for its spectacular Pillars of Creation, gaseous clouds towering over 9 trillion kilometers tall. The nebula became well known after the Hubble Space Telescope captured a dramatic image of the pillars in 1995.
Between 1995 and 1998, scientists believed the pillars to be a classic example of a Rayleigh-Taylor instability, which occurs when a light material supports a dense one in a gravitational field, as, for example, when a light salad oil is trying to support a layer of relatively dense vinegar. The dense material will fall in spikes into the lighter material, which in turn rises in bubbles into the denser material, until the fluids change places.
In 1998, however, Marc Pound of the University of Maryland used the Berkeley-Illinois-Maryland Array in Hat Creek, California, to measure the velocity and density of the gas in the pillars. He found them inconsistent with the measurements required to support the Rayleigh-Taylor explanation of the pillars.
The Livermore simulations reconcile Pound's measurements and the Rayleigh-Taylor explanation. Specifically, intense ultraviolet light from nearby stars heats and evaporates the surface layer of the Eagle Nebula, a gaseous cloud composed mostly of hydrogen and helium. The hot evaporated gas accelerates the cold, dense cloud. However, because it continues to be pulled gravitationally toward the hot evaporated gas, the accelerating cloud is Rayleigh-Taylor unstable.
The new theory considers possible variations in the stellar flux irradiating the clouds and in the finite cloud thickness. Finally, unlike the Rayleigh-Taylor model, which assumes incompressible matter, the new model takes into account the compressibility of heated gases.
The next step is to take the revised theory from simulation to experiments using the Omega laser at the University of Rochester in New York.
Contact: Randall Elder (925) 422-9914 (elder3@llnl.gov).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 



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