Croatian Children Have Higher Weapons-related Death Rate During And After Homeland War

Daily Science Journal (Feb. 7, 2008) — The Homeland War in Croatia, which occurred from 1991 to 1995, led to an increase in weapon-related deaths of children during and five years after the end of the war, according to a new report.

"After World War II until the beginning of the Homeland War in 1991, most children in Croatia were not exposed to firearms and explosives in their homes or communities," the authors write as background information in the article. "Unlike many countries, personal weapon ownership was not a custom in Croatia." This changed as the Homeland War--also called the Third Balkan War--moved into Croatian land. Citizens began purchasing grenades, firearms and other weapons on the black market or taking them from military barracks after the Yugoslav army left Croatia. The population remained overly militarized in the wake of the war; in 2007, 371,684 weapons were legally owned by Croatians.

Aida Mujkic, M.D., of the University of Iowa, Iowa City, and colleagues studied Croatian children from birth through age 19 who died of weapon-related injuries between 1986 and 2005. Statistics were obtained from Croatia's national vital statistics system and included traumatic injury deaths classified by intent, including homicide, suicide and unintentional categories.

Compared with the period before the war, rates of homicide and suicide with weapons more than tripled during the war--from .22 to .73 homicides and .51 to 1.64 suicides per 100,000 children. Unintentional weapon-related deaths also increased by more than six-fold, from .25 to 1.63 per 100,000 children.

"These increases persisted for five years following the end of the war and decreased more than five years after the war," the authors write. Weapons-related deaths in the early postwar period--1996 to 2000--remained more than twice as high as before the war, and the weapon-related suicide rate remained more than three times that of the pre-war period. Homicide and unintentional injury deaths decreased significantly in the late post-war period, 2001 to 2005, and suicide rates were the same as in the pre-war period. The number of children who died from causes other than weapons did not change over the course of the study.

"Programs that focus on the prevention of weapon-related injuries should be integrated into programs that assist countries in rebuilding after political unrest," the authors conclude. "The combination of psychological effects of war on children with an increased presence of weapons may present a particularly important area for prevention."

Journal reference: Arch Pediatr Adolesc Med. 2008;162[2]:140-144.

This study was supported by an NIH grant from the University of Iowa/Fogarty International Traumatic Injury Training Program.

Adapted from materials provided by JAMA and Archives Journals.

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Plastic Bottles Release Potentially Harmful Chemicals (Bisphenol A) After Contact With Hot Liquids

Daily Science Journal (Feb. 5, 2008) — When it comes to Bisphenol A (BPA) exposure from polycarbonate plastic bottles, it's not whether the container is new or old but the liquid's temperature that has the most impact on how much BPA is released, according to University of Cincinnati (UC) scientists.

Scott Belcher, PhD, tested polycarbonate plastic bottles like these for Bisphenol A. (Credit: Image courtesy of University of Cincinnati)

Scott Belcher, PhD, and his team found when the same new and used polycarbonate drinking bottles were exposed to boiling hot water, BPA, an environmental estrogen, was released 55 times more rapidly than before exposure to hot water.

"Previous studies have shown that if you repeatedly scrub, dish-wash and boil polycarbonate baby bottles, they release BPA. That tells us that BPA can migrate from various polycarbonate plastics," explains Belcher, UC associate professor of pharmacology and cell biophysics and corresponding study author. "But we wanted to know if 'normal' use caused increased release from something that we all use, and to identify what was the most important factor that impacts release."

"Inspired by questions from the climbing community, we went directly to tests based on how consumers use these plastic water bottles and showed that the only big difference in exposure levels revolved around liquid temperature: Bottles used for up to nine years released the same amount of BPA as new bottles."

BPA is one of many man-made chemicals classified as endocrine disruptors, which alter the function of the endocrine system by mimicking the role of the body's natural hormones. Hormones are secreted through endocrine glands and serve different functions throughout the body.

The chemical--which is widely used in products such as reusable water bottles, food can linings, water pipes and dental sealants--has been shown to affect reproduction and brain development in animal studies.

"There is a large body of scientific evidence demonstrating the harmful effects of very small amounts of BPA in laboratory and animal studies, but little clinical evidence related to humans," explains Belcher. "There is a very strong suspicion in the scientific community, however, that this chemical has harmful effects on humans."

Belcher's team analyzed used polycarbonate water bottles from a local climbing gym and purchased new bottles of the same brand from an outdoor retail supplier.

All bottles were subjected to seven days of testing designed to simulate normal usage during backpacking, mountaineering and other outdoor adventure activities.

The UC researchers found that the amount of BPA released from new and used polycarbonate drinking bottles was the same -- both in quantity and speed of release -- into cool or temperate water.

However, drastically higher levels of BPA were released once the bottles were briefly exposed to boiling water.

"Compared to the rate of release from the same bottle, the speed of release was 15 to 55 times faster," explains Belcher.

Prior to boiling water exposure, the rate of release from individual bottles ranged from 0.2 to 0.8 nanograms per hour. After exposure, rates increased to 8 to 32 nanograms per hour.

Belcher stresses that it is still unclear what level of BPA is harmful to humans. He urges consumers to think about how cumulative environmental exposures might harm their health.

"BPA is just one of many estrogen-like chemicals people are exposed to, and scientists are still trying to figure out how these endocrine disruptors--including natural phyto-estrogens from soy which are often considered healthy--collectively impact human health," he says. "But a growing body of scientific evidence suggests it might be at the cost of your health."

The UC team reports its findings in the Jan. 30, 2008 issue of the journal Toxicology Letters. UC graduate student Hoa Le and summer undergraduate research fellows Emily Carlson and Jason Chua also participated in this study, which was funded by a National Institute of Environmental Health Sciences grant.

Adapted from materials provided by University of Cincinnati.

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Tiny Avalanche Photodiode Detects Single UV Photons

Daily Science Journal (Feb. 1, 2008) — In a significant breakthrough, researchers at Northwestern University’s Center for Quantum Devices (CQD) have demonstrated visible-blind avalanche photodiodes (APDs) capable of detecting single photons in the ultraviolet region (360-200 nm).

Lower left, schematic diagram of a back illuminated single photon detector; Upper right, biasing circuit used to drive the single photon detector; Background, scanning electron micrograph of a processed array of single photon detectors. (Credit: Image courtesy of Northwestern University)

Previously, photomultiplier tubes (PMTs) were the only available technology in the short wavelength UV portion of the spectrum capable of single photon detection sensitivity. However, these fragile vacuum tube devices are expensive and bulky, hindering true systems miniaturization.

The Northwestern team, led by Manijeh Razeghi, Walter P. Murphy Professor of Electrical Engineering and Computer Science at Northwestern’s McCormick School of Engineering, became the world’s first to demonstrate back-illuminated single photon detection from a III-nitride photodetector. These back-illuminated devices, based on GaN compound semiconductors, benefit from the larger ionization coefficient for holes in this material. The back-illumination geometry will facilitate future integration of these devices with read-out circuitry to realize unique single-photon UV cameras. Towards that end, the team has already demonstrated excellent uniformity of the breakdown characteristics and gain across the wafer.

The devices are coupled with a quenching circuit and operated under large reverse bias, an arrangement termed in Geiger mode operation. The sensor system presents an effective photocurrent gain greater than 107, single photon detection efficiencies of 23 percent, dark count rates of less than 1 kHz, and no response to visible radiation.

Once optimized, discrete detectors could be combined with the ultraviolet LEDs already pioneered by the Center for Quantum Devices to create an inexpensive detection system capable of identifying the unique spectral fingerprints of a biological agent attack. They can also be paired with UV LEDs to create a new form of non-line of sight UV-communication, secure from remote eavesdropping.

These exciting new results were recently presented at the Defense Advanced Research Projects Agency (DARPA) during the Single Photon Detection Workshop hosted by Dr. Matthew Goodman, and held in Arlington, VA on Nov. 27, 2007 and at the SPIE Photonics West Conference held in San Jose, CA on Jan. 19-24, 2008. This work was also published in the July 23, 2007 issue of the journal Applied Physics Letters.

Adapted from materials provided by Northwestern University.

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Cell Phone Sensors Detect Radiation To Thwart Nuclear Terrorism

Daily Science Journal (Jan. 29, 2008) — Researchers at Purdue University are working with the state of Indiana to develop a system that would use a network of cell phones to detect and track radiation to help prevent terrorist attacks with radiological "dirty bombs" and nuclear weapons.

Purdue physics professor Ephraim Fischbach, at right, and nuclear engineer Jere Jenkins review radiation-tracking data as part of research to develop a system that would use a network of cell phones to detect and track radiation. Such a system could help prevent terrorist attacks with radiological "dirty bombs" and nuclear weapons by blanketing the nation with millions of cell phones equipped with radiation sensors able to detect even light residues of radioactive material. Because cell phones already contain global positioning locators, the network of phones would serve as a tracking system. (Credit: Purdue News Service photo/David Umberger)

Such a system could blanket the nation with millions of cell phones equipped with radiation sensors able to detect even light residues of radioactive material. Because cell phones already contain global positioning locators, the network of phones would serve as a tracking system, said physics professor Ephraim Fischbach. Fischbach is working with Jere Jenkins, director of Purdue's radiation laboratories within the School of Nuclear Engineering.

"It's the ubiquitous nature of cell phones and other portable electronic devices that give this system its power," Fischbach said. "It's meant to be small, cheap and eventually built into laptops, personal digital assistants and cell phones."

The system was developed by Andrew Longman, a consulting instrumentation scientist. Longman developed the software for the system and then worked with Purdue researchers to integrate the software with radiation detectors and cell phones. Cellular data air time was provided by AT&T.

The research has been funded by the Indiana Department of Transportation through the Joint Transportation Research Program and School of Civil Engineering at Purdue.

"The likely targets of a potential terrorist attack would be big cities with concentrated populations, and a system like this would make it very difficult for someone to go undetected with a radiological dirty bomb in such an area," said Longman, who also is Purdue alumnus. "The more people are walking around with cell phones and PDAs, the easier it would be to detect and catch the perpetrator. We are asking the public to push for this."

Tiny solid-state radiation sensors are commercially available. The detection system would require additional circuitry and would not add significant bulk to portable electronic products, Fischbach said.

The technology is unlike any other system, particularly because the software can work with a variety of sensor types, he said.

"Cell phones today also function as Internet computers that can report their locations and data to their towers in real time," Fischbach said. "So this system would use the same process to send an extra signal to a home station. The software can uncover information from this data and evaluate the levels of radiation."

The researchers tested the system in November, demonstrating that it is capable of detecting a weak radiation source 15 feet from the sensors.

"We set up a test source on campus, and people randomly walked around carrying these detectors," Jenkins said. "The test was extremely safe because we used a very weak, sealed radiation source, and we went through all of the necessary approval processes required for radiological safety. This was a source much weaker than you would see with a radiological dirty bomb."

Officials from the Indiana Department of Transportation participated in the test.

"The threat from a radiological dirty bomb is significant, especially in metropolitan areas that have dense populations," said Barry Partridge, director of INDOT's Division of Research and Development.

Long before the sensors would detect significant radiation, the system would send data to a receiving center.

"The sensors don't really perform the detection task individually," Fischbach said. "The collective action of the sensors, combined with the software analysis, detects the source. The system would transmit signals to a data center, and the data center would transmit information to authorities without alerting the person carrying the phone. Say a car is transporting radioactive material for a bomb, and that car is driving down Meridian Street in Indianapolis or Fifth Avenue in New York. As the car passes people, their cell phones individually would send signals to a command center, allowing authorities to track the source."

The signal grows weaker with increasing distance from the source, and the software is able to use the data from many cell phones to pinpoint the location of the radiation source.

"So the system would know that you were getting closer or farther from something hot," Jenkins said. "If I had handled radioactive material and you were sitting near me at a restaurant, this system would be sensitive enough to detect the residue. "

The Purdue Research Foundation owns patents associated with the technology licensed through the Office of Technology Commercialization.

In addition to detecting radiological dirty bombs designed to scatter hazardous radioactive materials over an area, the system also could be used to detect nuclear weapons, which create a nuclear chain reaction that causes a powerful explosion. The system also could be used to detect spills of radioactive materials.

"It's impossible to completely shield a weapon's radioactive material without making the device too heavy to transport," Jenkins said.

The system could be trained to ignore known radiation sources, such as hospitals, and radiation from certain common items, such as bananas, which contain a radioactive isotope of potassium.

"The radiological dirty bomb or a suitcase nuclear weapon is going to give off higher levels of radiation than those background sources," Fischbach said. "The system would be sensitive enough to detect these tiny levels of radiation, but it would be smart enough to discern which sources posed potential threats and which are harmless."

The team is working with Karen White, senior technology manager at the Purdue Research Foundation, to commercialize the system. For more information on licensing the cell phone sensor technology, contact White at (765) 494-2609

Adapted from materials provided by Purdue University.

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Faster, More Sensitive Method For Detecting Anthrax

Daily Science Journal (Nov. 8, 2007) — Amid continuing concerns that anthrax might be used as a bioterrorism weapon, government researchers report development of a faster, more sensitive blood test for detecting the deadly toxins produced by the anthrax bacterium, Bacillus anthracis. The test produces results in only 4 hours and could save lives by allowing earlier detection of infection, they say.

Anthrax spores as photographed under an electron microscope. (Credit: Courtesy of Centers for Disease Control and Prevention)

Standard identification of anthrax (Bacillus anthracis) infection relies on a combination of time-consuming steps, including cell culture and gene amplification, which can take several days to provide a diagnosis and have limitations for detecting early stages of infection. Early diagnosis is critical for effective treatment of pulmonary or inhalation anthrax, the most deadly form.

John R. Barr and colleagues in a multi-center team effort used a form of mass spectrometry to detect the presence of 'lethal factor,' the key toxin produced by the anthrax bug, in the blood of monkeys with inhalation anthrax.

The method took only four hours to identify the toxin and detected it at very low levels, demonstrating its potential for early detection of infection, the researchers say. The new method also shows promise as a research tool for providing a better understanding of the anthrax infection cycle and for evaluating the effectiveness of different therapies and methods to fight infections.

The article "Detection and Quantification of Anthrax Lethal Factor in Serum by Mass Spectrometry" is scheduled for publication in the Nov. 22 issue of ACS' Analytical Chemistry.

Adapted from materials provided by American Chemical Society, via EurekAlert!, a service of AAAS.

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