OREGON STATE UNIVERSITY

scientific research and advances

Research offers promising new approach to treatment of lung cancer

CORVALLIS, Ore. – Researchers have developed a new drug delivery system that allows inhalation of chemotherapeutic drugs to help treat lung cancer, and in laboratory and animal tests it appears to reduce the systemic damage done to other organs while significantly improving the treatment of lung tumors.

This advance in nanomedicine combines the extraordinarily small size of nanoparticles, existing cancer drugs, and small interfering RNA (siRNA) that shut down the ability of cancer cells to resist attack.

The combination of these forces resulted in the virtual disappearance of lung tumors in experimental animals.

Lung cancer is the leading cancer killer in both men and women. Despite advances in surgery, chemotherapy still plays a major role in its treatment. However, that treatment is constrained by the toxic effects of some drugs needed to combat it and the difficulty of actually getting those drugs into the lungs.

The findings were made by Oleh Taratula at Oregon State University and Tamara Minko and O. Garbuzenko at Rutgers University and the Cancer Institute of New Jersey. They were just published in the Journal of Controlled Release.

“Lung cancer damage is usually not localized, which makes chemotherapy an important part of treatment,” said Taratula, an assistant professor in the OSU College of Pharmacy and co-author on this study.  “However, the drugs used are toxic and can cause organ damage and severe side effects if given conventionally through intravenous administration.

“A drug delivery system that can be inhaled is a much more efficient approach, targeting just the cancer cells as much as possible,” he said. “Other chemotherapeutic approaches only tend to suppress tumors, but this system appears to eliminate it.”

A patent is being applied for on the technology, and more testing will be necessary before it is ready for human clinical trials, the researchers said.

The foundation of the new system is a “nanostructured lipid nanocarrier,” tiny particles much smaller than a speck of dust that are easily inhaled and also readily attach to cancer cells. This carrier system delivers the anticancer drug. However, it also brings siRNA that makes the cancer cell more vulnerable.

Cancer cells often have two forms of resistance to drugs – “pump” resistance that tends to pump the drug out of cells, and “nonpump” resistance that helps keep the cell from dying. The siRNA used in this system helps to eliminate both those forms of resistance, and leaves the cancer cell vulnerable to the drug being used to kill it.

By being inhaled, this system also avoids degradation of the chemotherapeutic agents that occurs when they are injected, researchers said. They arrive in more intact form, ready to do their job on lung cancer cells, while minimizing any side effects.

In more conventional chemotherapy for lung cancer, the drugs tend to accumulate in the liver, kidney and spleen, with much less of the drugs ever making it to the lungs. In this study, the amount of the drug delivered to the lungs rose to 83 percent with the inhalation approach, versus 23 percent with injection.

This work was supported by the National Cancer Institute, National Science Foundation, and the Department of Defense.

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Oleh Taratula, 541-737-3424

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Study traces origin of cirrus clouds primarily to mineral dust and metals

CORVALLIS, Ore. – Researchers studying the origin of cirrus clouds have found that these thin, wispy trails of ice crystals are formed primarily on dust particles and some unusual combinations of metal particles – both of which may be influenced by human activities.

The findings are important, scientists say, because cirrus clouds cover as much as one-third of the Earth and play an important role in global climate. Depending on altitude and the number and size of ice crystals, cirrus clouds can cool the planet by reflecting incoming solar radiation – or warm it by trapping outgoing heat.

However, what the net effect is, and how humans impact it, is still unclear.

Results of the study, which was funded by NASA and the National Science Foundation, were published this week in the journal Science.

“Cirrus clouds are complicated but the important message is that dust and certain metals provide the seeds for a majority of the ice crystals that form the clouds,” said Cynthia Twohy, an Oregon State University atmospheric scientist and co-author on the study. “Other particle types – including bacteria and soot from human-produced combustion or natural sources – don’t seem to contribute much to the nuclei of cirrus crystals.

“These biological particles may be important in the formation of lower altitude clouds,” added Twohy, who is a professor in OSU’s College of Earth, Ocean, and Atmospheric Sciences. “But they were surprisingly absent from the particles we sampled from cirrus clouds.”

During the study, led by scientists at the Massachusetts Institute of Technology and the National Oceanic and Atmospheric Administration, the researchers conducted flight missions from 2002 to 2011 over North America and Central America at 20,000 to 50,000 feet elevation, where cirrus clouds often form. As their planes flew through the clouds, researchers captured and heated the ice crystals, which then evaporated, leaving behind a tiny kernel that they analyzed using an onboard mass spectrometer.

Despite the length of the study and its different geographic locations, the researchers found similar outcomes: About 60 percent of the cloud particles they analyzed could be traced to mineral dust blown into the atmosphere, or to metallic aerosols.

“Mineral dust can occur naturally,” Twohy said, “or it can be influenced by human activities. Certainly the major deserts like the Sahara and Gobi are enormous sources of mineral dust. But agriculture, over-grazing and climate and land-use changes can also contribute.”

Twohy said the scientists have not yet traced the origin of the dust to see how much of it came from natural versus anthropogenic causes. The metallic aerosols, she added, are unusual and may be easier to trace to specific sources. Containing elements like lead, zinc, tin and copper, they appear to be from industrial activities, according to other scientists in the study.

“As the climate warms, it is possible that we will see an expansion of desert lands, which could lead to even more dust entering the atmosphere,” Twohy said. “That could create more cirrus clouds, but what that means in terms of warming or cooling is unsure and an area for future research.”

An expert in cloud formation, Twohy has been involved in some 30 different aircraft missions over the years to understand the composition and characteristics of clouds and how they are influenced by pollution. She has studied clouds in North America, Central America, South America, Africa, the Southern Ocean and the Indian Ocean.

“At lower altitudes, clouds are known to be influenced by pollution – especially near cities,” Twohy said. “They have more droplets, they reflect more light and they rain less. The impacts of cirrus clouds on climate are much more complex. But this gives us a starting point because we now have a better understanding of the particle types and mechanisms that lead to their formation.”

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Cynthia Twohy, 541-737-5690

Linus Pauling science on tap for Corvallis Science Pub

CORVALLIS, Ore. – The potential health benefits of vitamin C may be Linus Pauling’s most famous legacy among the public, but the Oregon State University graduate and two-time Nobel Prize winner is better known among scientists for deep insights into chemistry and its application to medicine. 

The May 13 Corvallis Science Pub will focus on little-known highlights of Pauling’s life and on how scientists are applying his findings today.

Science Pub presentation begins at 6 p.m. at the Old World Deli, located at 341 S.W. Second St. in Corvallis. It is free and open to the public.

The event will feature two speakers – Chris Petersen of the Special Collections and Archives Research Center in OSU’s Valley Library and Steve Lawson, administrative officer at the Linus Pauling Institute on campus. The institute is celebrating its 40th anniversary this year.

Petersen authors The Pauling Blog and has overseen production of websites and videos that describe Pauling’s lifelong research. Lawson has been associated with the institute since 1977 when it was located in the San Francisco Bay Area before moving to Oregon State. 

Sponsors of Science Pub include Terra magazine at OSU, the Downtown Corvallis Association and the Oregon Museum of Science and Industry.

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Chris Peterson, Valley Library, 541-737-2810

Stephen Lawson, Linus Pauling Institute, 541-737-5080

Outpatients, hospital patients face different problems with antibiotic resistance

CORVALLIS, Ore. – A new study concludes that problems with antibiotic resistance faced by outpatients may be as bad as those in hospitalized patients, and that more studies of outpatients are needed – both to protect their health and to avoid inappropriate or unnecessary drug use.

Antibiotic resistance is a huge and growing problem in both hospital and outpatient settings. Failure to select an effective antibiotic, without appropriate consideration for this resistance, can increase the risk of continued illness or death.

While 126 million prescriptions a year for antimicrobial drugs are given to people outside of hospitals, less has been done with them, compared to inpatients, to monitor their levels of antibiotic resistance.

The new analysis examined more than 16,000 cultures for resistance to some commonly used antibiotics. It found that outpatients can face resistance issues that sometimes are similar to those of people in hospitals – but that these problems can also be either more or less severe.

The findings were reported in Diagnostic Microbiology and Infectious Disease by researchers from Oregon State University, Oregon Health and Science University, and Kaiser Permanente Northwest.

“Hospitals for some time have been producing what are called antibiograms, a compilation of data to provide insights into local problems with antibiotic resistance,” said Jessina McGregor, assistant professor in the OSU College of Pharmacy, who is an expert in antibiotic resistance issues and lead author on this study.

“Traditionally these findings have been shared with doctors to help them select the best antibiotics for their patients’ infections,” she said. “However, in many outpatient settings this same level of information has not been available. We found there are enough differences that we need to start doing more studies with the outpatient groups, in order to help doctors provide patients with the best possible care for their infections, and prevent the spread of resistance.”

The researchers also noted that more than half of all antibiotics prescribed to outpatients for acute respiratory infections are unnecessary. This can speed the resistance of bacteria to antibiotic treatment.

Antibiotic resistance historically began to show up in hospitals before it was found in the larger community, researchers say. Because of this, hospitals have been more aggressive in working to monitor, understand and prevent unnecessary antibiotic use.

As patient records increasingly become electronic, both in the hospital and in outpatient clinics, it will be possible for more health care systems to produce outpatient antibiograms, McGregor said, and that will be “a step in the right direction.”

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Jessina McGregor, 503-494-4722

Soil parasite costs Northwest wheat growers $51 million in lost revenue, says OSU

CORVALLIS, Ore. – A microscopic parasitic roundworm is costing Pacific Northwest wheat growers $51 million in lost revenue each year because it's cutting grain yields by an average of about 5 percent, according to estimates by Oregon State University researchers.

Called the root-lesion nematode, the transparent, eel-shaped roundworm lives in the soil and feeds on the roots of wheat, barley, oats and many other crops. This limits the crops' ability to take up nutrients and water, leaving plants with smaller heads and yellowed leaves.

"The presence of nematodes is usually confused with root rot, viruses or lack of nutrition because the effect on crops looks the same," said Dick Smiley, a plant pathologist at OSU's Columbia Basin Agricultural Research Center in Pendleton. “But nematodes often go undetected because they're not well-known, and they're transparent and thinner than a human hair.”

Researchers have detected the root-lesion nematode in about 90 percent of fields sampled in Idaho, Montana, Oregon, and Washington, according to Smiley, who has studied the pest since 1999. Population densities of nematodes high enough to reduce yields have been detected in 60 percent of fields sampled in Oregon and Washington. The roundworm wreaks the most havoc in drier areas where wheat and barley grow.

Most nematodes are beneficial to agriculture by helping decompose organic matter. Some, however, are parasitic to plants or animals. They spread easily, hitchhiking to new locations via the wind, animals, farm equipment and boots. It's nearly impossible to eradicate them once they're established.

Another harmful roundworm, the cereal cyst nematode, is also damaging wheat, barley and oats in the Pacific Northwest. First identified in western Oregon in 1974, it is now found in eight western states.

Wheat farmers in Idaho, Oregon and Washington are estimated to lose $3.4 million in revenue each year to cereal cyst nematodes, according to OSU calculations. Researchers arrived at the figure by considering a range of factors, including the percentage of fields infested with damaging densities of nematodes, as well as the yields and farmgate value for crops in these infested areas.

OSU scientists are studying crop management strategies to mitigate the worms' impact. The most effective tactic they've found is a three-year crop rotation where farmers skip two years between wheat plantings.

Rotations vary depending upon which nematode is causing problems. Root-lesion nematodes are well-managed by planting winter wheat the first year and spring barley the second year and then letting the field go fallow the third year. Cereal cyst nematodes are best-managed by rotating wheat or barley with broadleaf crops.

Crop damage can also be alleviated to a limited extent by applying extra fertilizer and water. There are no chemicals legally available for wheat and barley growers to kill the two types of nematodes.

OSU researchers have also tested more than 20 wheat, barley and oat cultivars to determine how badly yields are reduced. Most Pacific Northwest wheat varieties don't resist harmful nematodes.

In OSU's tests, nearly every variety suffered severe root injury. Only the hard red spring wheat WB-Rockland prevented cereal cyst nematodes from reproducing while also maintaining consistent yields. UI Stone, a soft white spring wheat, and Buck Pronto, a hard red spring wheat, allowed nematode populations to thrive but still produced a steady crop.

Additionally, University of Idaho, Washington State University, U.S. Department of Agriculture, and commercial wheat breeders are crossing sources of resistance with a number of wheat varieties to create new cultivars that can potentially stand up to the cereal cyst and root-lesion nematodes.

OSU researchers recommend growers have their soil tested for nematodes. Addresses for testing labs, as well as information about management strategies for farmers, are available in two OSU Extension factsheets at http://bit.ly/OSU_ExtBulletin3 and http://bit.ly/OSU_ExtBulletin2.

The U.S. Department of Agriculture, Washington State University and the University of Idaho are collaborators with OSU on its cereal cyst nematode research.

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Richard Smiley, 541-278-4397

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OSU nematode expert Richard Smiley

Dick Smiley, a plant pathologist at Oregon State University, examines the roots of young wheat plants. (Photo by Lynn Ketchum.)

Excess vitamin E intake not a health concern

CORVALLIS, Ore. – Despite concerns that have been expressed about possible health risks from high intake of vitamin E, a new review concludes that biological mechanisms exist to routinely eliminate excess levels of the vitamin, and they make it almost impossible to take a harmful amount.

No level of vitamin E in the diet or from any normal use of supplements should be a concern, according to an expert from the Linus Pauling Institute at Oregon State University. The review was just published in the Journal of Lipid Research.

“I believe that past studies which have alleged adverse consequences from vitamin E have misinterpreted the data,” said Maret Traber, an internationally recognized expert on this micronutrient and professor in the OSU College of Public Health and Human Sciences.

“Taking too much vitamin E is not the real concern,” Traber said. “A much more important issue is that more than 90 percent of people in the U.S. have inadequate levels of vitamin E in their diet.”

Vitamin E is an antioxidant and a very important nutrient for proper function of many organs, nerves and muscles, and is also an anticoagulant that can reduce blood clotting. It can be found in oils, meat and some other foods, but is often consumed at inadequate dietary levels, especially with increasing emphasis on low-fat diets.

In the review of how vitamin E is metabolized, researchers have found that two major systems in the liver work to control the level of vitamin E in the body, and they routinely excrete excessive amounts. Very high intakes achieved with supplementation only succeed in doubling the tissue levels of vitamin E, which is not harmful.

“Toxic levels of vitamin E in the body simply do not occur,” Traber said. “Unlike some other fat-soluble vitamins such as vitamins A and D, it’s not possible for toxic levels of vitamin E to accumulate in the liver or other tissues.”

Vitamin E, because of its interaction with vitamin K, can cause some increase in bleeding, research has shown. But no research has found this poses a health risk.

On the other hand, vitamin E performs many critical roles in optimum health. It protects polyunsaturated fatty acids from oxidizing, may help protect other essential lipids, and has been studied for possible value in many degenerative diseases. Higher than normal intake levels may be needed for some people who have certain health problems, and smoking has also been shown to deplete vitamin E levels.

Traber said she recommends taking a daily multivitamin that has the full RDA of vitamin E, along with consuming a healthy and balanced diet.

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Maret Traber, 541-737-7977

Co-Q10 deficiency may relate to statin drugs, diabetes risk

CORVALLIS, Ore. – A laboratory study has shown for the first time that coenzyme Q10 offsets cellular changes that may be linked to a side-effect of some statin drugs - an increased risk of adult-onset diabetes.

Statins are some of the most widely prescribed drugs in the world, able to reduce LDL, or “bad” cholesterol levels, and the risk of heart attacks or other cardiovascular events. However, their role in raising the risk of diabetes has only been observed and studied in recent years.

The possibility of thousands of statin-induced diabetics is a growing concern, and led last year to new labeling and warnings by the Food and Drug Administration about the drugs, especially when taken at higher dosage levels.

The findings of the new research were published as a rapid communication in Metabolic Syndrome and Related Disorders, and offer another clue to a possible causative mechanism of this problem.

Pharmacy researchers at Oregon State University who authored the study said the findings were made only in laboratory analysis of cells, and more work needs to be done with animal and ultimately human studies before recommending the use of coenzyme Q10 to help address this concern.

“A number of large, randomized clinical trials have now shown that use of statins can increase the risk of developing type-2 diabetes by about 9 percent,” said Matthew K. Ito, an OSU professor of pharmacy and president-elect of the National Lipid Association.

“This is fairly serious, especially if you are in the large group of patients who have not yet had a cardiovascular event, but just take statin drugs to lower your risks of heart disease,” Ito said.

A suspect in this issue has been altered levels of a protein called GLUT4, which is part of the cellular response mechanism, along with insulin, that helps to control blood sugar levels. A reduced expression of GLUT4 contributes to insulin resistance and the onset of type-2 diabetes, and can be caused by the use of some statin drugs.

The statins that reduce cholesterol production also reduce levels of coenzyme Q10, research has shown. Coenzyme Q10 is needed in cells to help create energy and perform other important functions. And this study showed in laboratory analysis that if coenzyme Q10 is supplemented to cells, it prevents the reduction in GLUT4 induced by the statins.

Not all statin drugs, however, appear to cause a reduction in GLUT4.

The problems were found with one statin, simvastatin, that is “lipophilic,” which means it can more easily move through the cell membrane. Some of the most commonly used statins are lipophilic, including simvastatin, atorvastatin, and lovastatin. All of these statins are now available as generic drugs, and high dosage levels have been most often linked with the increase in diabetes.

Tests in the new study done with a “hydrophilic” statin, in this case pravastatin, did not cause reduced levels of GLUT4. Pravastatin is also available as a generic drug.

“The concern about increasing levels of diabetes is important,” Ito said. “We need to better understand why this is happening. There’s no doubt that statins can reduce cardiovascular events, from 25-45 percent, and are very valuable drugs in the battle against heart disease. It would be significant if it turns out that use of coenzyme Q10 can help offset the concerns about statin use and diabetes.”

Before that conclusion can be reached, the researchers said, additional studies are needed on coenzyme Q10 supplementation and the pathogenesis of statin-induced diabetes.

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Matthew K. Ito, 503-494-3657

Remote-controlled aircraft to fly near Hermiston for potato research

HERMISTON, Ore. – Two small, remote-controlled aircraft are expected to start flying over potato fields in the Hermiston area this month as part of Oregon State University's efforts to help farmers more efficiently use water, fertilizers and pesticides to bolster yields and cut costs.

While taking photographs, the aircraft will fly over 50 acres of OSU's 300-acre Hermiston Agricultural Research and Extension Center (HAREC), as well as several crop circles totaling about 1,000 acres at a research cooperative farm west of Boardman. The flights will take place at least three times a week until the potatoes are harvested in the fall, beginning with a test run Wednesday at the Boardman farm.

OSU researchers will use various cameras on the aircraft to photograph the potato plants. The cameras will include ones that detect different wavelengths of light. One of these wavelengths, infrared, is reflected by plants, but unhealthy plants reflect less of it, and in infrared photographs sick plants are much darker. Researchers will also explore using other wavelengths of light to determine which ones will be most helpful in identifying troubled plants.

Researchers aim to see if the cameras, which are capable of zooming in on a leaf, can detect plants that aren't getting enough fertilizer and water. They'll purposely reduce irrigation and fertilizer on some plants and will then see how quickly, if at all, the equipment detects the stressed plants. If it works, the scientists hope that the project will continue in subsequent years so they can test the cameras to also find plants that are plagued by insects and diseases. The idea is to help farmers take action before larger crop losses occur and it becomes more difficult and expensive to control the problem.

"The key is to pick up plants that are just beginning to show stress so you can find a solution quickly, so the grower doesn’t have any reduced yield or quality issues," said Phil Hamm, the director of HAREC. "This in turn can save money. It's an early warning system for plants with issues as well as an opportunity for growers to reduce costs by being more efficient in water and fertilizer use."

Potatoes were chosen as the focus of the research because they're a high-valued crop, expensive to raise and must be carefully managed to reduce internal and external blemishes and irregular growth spurts, said Don Horneck, an agronomist with the OSU Extension Service. One of Oregon's leading crops, the state's farmers sold $173 million of potatoes in 2012, according to the U.S. Department of Agriculture. But spuds are prone to devastating problems caused by diseases and insects, said Horneck, who is the lead researcher from OSU on the project.

"They are one of the most difficult and expensive crops to grow," he said, adding that it typically costs Hermiston farmers $4,000 or more per acre to grow them. That equates to about $500,000 for the average size of field in the area.

OSU hopes that the aircraft it tests will reduce these costs. The aircraft that will fly over OSU's land is called a HawkEye and is sold by a company called Tetracam. About the size of a suitcase and weighing only 8 pounds, its maximum flight time is 10-30 minutes. The hull-less, battery-operated machine is easy to operate and was made for farmers with plots of land that are less than one square mile. A motor and propeller allow it to take off on four wheels. A parachute keeps it in the air. Photos and videos of it are at http://bit.ly/10LDbjt.

A delta-winged aircraft made of plastic foam will fly over the private farm. Made by Procerus Technologies and called a Unicorn, it has a wingspan of no more than 6 feet and weighs less than 6 pounds. A bungee cord launches it like a slingshot. A factsheet on it is at http://bit.ly/XTqioS.

OSU is inviting the public to see the HawkEye fly during its potato field day at its Hermiston research center on June 26.

Allaying concerns about privacy, Hamm said, "These unmanned aircraft are for agricultural research only and will be used to do nothing more than that. This is about helping our local growers do a better job of growing crops, something HAREC has been doing for the past 102 years."

The Federal Aviation Administration has authorized the flights of the aircraft, which aren't allowed to fly higher than 400 feet and must stay within sight of the operator, typically less than a mile away.

OSU is leasing the aircraft from Boeing Research & Technology. n-Link, an information technology firm in Bend, is also a partner in the project. Ray Hunt, a plant physiologist with the USDA in Beltsville, Md., will collaborate with OSU's Horneck on the data analysis.

OSU aims to become one of the nation's premiere universities using unmanned aircraft for research. It is using or has plans to use them in studies on natural resources, wildlife, land-use management, forestry, oceanography and engineering.

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Phil Hamm, 541-567-8321

Invention could make spent nuclear fuel useful for irradiation purposes

CORVALLIS, Ore. – A researcher at Oregon State University has invented a way to use spent nuclear fuel to produce the gamma rays needed to irradiate medical supplies, food and other products – an advance that could change what is now a costly waste disposal concern into a valued commodity.

The technology, if widely implemented, might allow each of the 104 nuclear reactors in the United States to create a revenue stream of $10 million a year while providing thousands of new jobs. And by lowering the cost of irradiation, it could become commercially feasible for a wider range of uses.

A provisional patent has been issued on the technology, and commercialization efforts are under way through a private company, G-Demption LLC, created for that purpose.

“This is essentially a way to re-use spent nuclear fuel for a valuable purpose,” said Russell Goff, a masters student in the OSU Department of Nuclear Engineering and Radiation Health Physics. “Until now no one really thought to do this. But this approach is safe, practical and economical. Instead of treating all nuclear waste as a disposal problem, we could be putting much of it to good use.”

Irradiation is a growing industry, and is commonly used in the sterilization of medical supplies such as bandages or syringes. It’s also widely approved for helping to preserve foods – many spices, and some fruits and meat products are irradiated. The use of gamma radiation for these purposes does not make the underlying product radioactive, and generally has no effects on it that are any more pronounced than other sterilization or preservation technologies.

However, the gamma ray sterilization industry is constrained by the need for cobalt 60, the radioactive isotope most commonly used.

“The U.S. already uses about half of the world’s supply of cobalt 60 for various types of irradiation, and the process can be expensive,” Goff said. “The new system we’ve created should be significantly less expensive, and as such could open the technology to more routine uses. We could double the world supply of gamma rays with this new technology and still won’t come close to meeting the market demand for this valuable resource.”

Sterile medical supplies are a huge market for gamma irradiation, Goff said, and increased used of irradiation could reduce the need for sterilization with ethylene oxide gas, which is a highly toxic and flammable gas.

The system Goff has invented adds another level of protection to prevent unwanted fission products from escaping the spent nuclear fuel and entering the environment, but allows gamma radiation to be released in a controlled manner for irradiation purposes. Because recently spent nuclear fuel – less than 12 years old - still has fairly intense levels of radiation, it provides an economical way to irradiate products.

The nuclear waste handling systems needed to use the new technology are similar to those already being used at nuclear power plants, he said, and the process of sterilizing the products is almost identical to processes used in the cobalt 60 irradiation industry today.

Aside from providing a commercial use for spent nuclear fuel, the approach would also reduce the significant expense of otherwise storing it, Goff noted. This system might also have special appeal in developing countries, where refrigeration and other approaches to preserving food, as well as access to sterile medical supplies, are not always readily available.

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Russell Goff
515-231-0736

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Pedestrians at serious risk when drivers are “permitted” to turn left

The report this story is based on is available online: http://bit.ly/kZJkWs

CORVALLIS, Ore. – A study to examine driver behavior in permitted left turns has identified what researchers call an “alarming” level of risk to pedestrians crossing the street – about 4-9 percent of the time, drivers don’t even bother to look and see if there are pedestrians in their way.

As opposed to a “protected” left turn, in which a solid green arrow gives a driver the complete right of way in a left-turn lane, a “permitted” left turn is often allowed by a confusing hodgepodge of signals, and drivers may have to pick their way through narrow windows of oncoming traffic.

This difficult driving maneuver, which is played out millions of times a day around the world, is fraught with risk for unwary pedestrians, who too often appear to be an afterthought.

 The danger is much higher than had been realized, experts say.

“There are far more pedestrian crashes in marked crosswalks than anywhere else on roads, and pedestrians already have a false sense of security,” said David Hurwitz, an assistant professor of transportation engineering at Oregon State University. “This study found that one key concern is permitted left turns.”

As they wait to turn left, sometimes taking a narrow opportunity to lunge into a stream of oncoming traffic, drivers focus most of their attention on the vehicular traffic and the traffic signal, rather than any pedestrians crossing the street, the research showed. The heavier the traffic, the less attention paid to pedestrians.

In a controlled analysis in a full-scale driving simulator that monitored specific eye movements, the engineers found that about one time in 10 or 20, the driver didn’t even look to see if a pedestrian was there before moving into the intersection. This suggests a major level of risk to pedestrians, researchers said, if they assume that drivers not only will look for them, but will allow them to cross the street.

The problem is aggravated by “permitted” left turn signals that vary widely, from state to state and sometimes even from one city to the next. Such turns might be allowed by a circular green light, a flashing circular yellow light, a flashing circular red light, or even a flashing yellow arrow. More consistent national standards regarding the flashing yellow arrow were recommended as recently as 2009, but the process of upgrading signals across the nation takes time.

The danger is sufficiently high, the researchers concluded, that more states and cities should consider prohibiting permitted left turns while pedestrians are allowed to be in the crosswalk. In Washington County, Ore., traffic managers recently did just that, after receiving a high number of complaints about pedestrian-vehicle conflicts.

“In traffic management you always have multiple goals, which sometimes conflict,” Hurwitz said. “You want to move traffic as efficiently as possible, because there’s a cost to making vehicles wait. You use more fuel, increase emissions and waste people’s time. The permitted left turn can help with efficiency.

“But the safety of the traveling public is also critical,” he said. “Sometimes the goal of safety has to override the goal of efficiency, and we think this is one of those times.”

Also of some interest, the study found preliminary evidence to suggest that the currently-mandated type of signal, which uses four heads instead of three, offers no change in driver behavior. However, the cost to implement a four-head signal is about $800 more than retrofitting the three-head version, which is widely used around the nation. Many millions of dollars might be saved nationally by using the simpler signal.

The findings of these studies have been compiled in a report by OSU and Portland State University researchers to the Oregon Transportation Research and Education Consortium, which funded the research. They will also be presented this year at the Driving Assessment Conference in New York and the Western District ITE meeting in Arizona.

OSU has a sophisticated driving simulator research facility, which allows test subjects to see, experience and react to realistic driving experiences while scientists study their reactions and behavior. This study was done with 27 subjects experiencing 620 permitted left turn maneuvers.

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David Hurwitz, 541-737-9242

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Tracking eye movement


"Permitted" left turn

"Permitted" left turn