Tuesday, May 25, 2010

20th century one of driest in 9 centuries for northwest Africa

Droughts in the late 20th century rival some of North Africa's major droughts of centuries past, reveals new research that peers back in time to the year 1179.

The first multi-century drought reconstruction that includes Morocco, Algeria and Tunisia shows frequent and severe droughts during the 13th and 16th centuries and the latter part of the 20th century.

Ramzi Touchan of the University of Arizona's Laboratory of Tree-Ring Research teaches students techniques for taking tree-ring cores during his field work in Algeria.
IMAGE : Ramzi Touchan of the University of Arizona's Laboratory of Tree-Ring Research teaches students techniques for taking tree-ring cores during his field work in Algeria.

Credit: Photo courtesy of R. Touchan, University of Arizona.

An international research team figured out northwest Africa's climate history by using the information recorded in tree rings. The oldest trees sampled contain climate data from the medieval period. One tree-ring sample from Morocco dates back to the year 883.

"Water issues in this part of the world are vital," said lead researcher Ramzi Touchan of the University of Arizona. "This is the first regional climate reconstruction that can be used by water resource managers."

In most of North Africa, instruments have been recording weather information for 50 years or less, too short a time to provide the long-term understanding of regional climate needed for resource planning, he said.

"One of the most important ways to understand the climate variability is to use the proxy record, and one of the most reliable proxy records is tree rings," said Touchan, an associate research professor at UA's Laboratory of Tree-Ring Research.

The team has developed the first systematically sampled network of tree-ring chronologies across northwest Africa, said co-author David Meko, also of UA's Laboratory of Tree-Ring Research.

The network allowed the researchers to analyze the patterns of past droughts over the whole region, said Meko, a UA associate research professor. The width of the annual growth rings on trees in semi-arid environments is highly correlated with the amount of precipitation.

The prolonged drought in northwest Africa from 1999-2002 killed many Atlas cedar trees. This photo is from a site in Algeria where tree-ring researcher Ramzi Touchan took samples to develop a drought history of the region. The trees, also known as Cedrus atlantica, are native to the Atlas Mountains of northwest Africa.


IMAGE:  The prolonged drought in northwest Africa from 1999-2002 killed many Atlas cedar trees. This photo is from a site in Algeria where tree-ring researcher Ramzi Touchan took samples to develop a drought history of the region. The trees, also known as Cedrus atlantica, are native to the Atlas Mountains of northwest Africa.

Credit: Photo courtesy of R. Touchan, University of Arizona.

The team found the region's 20th-century drying trend matches what climate models predict will occur as the climate warms. The research is the first to compare projections from climate models with tree-ring-based reconstructions of the region's past climate.

The region's trees and dead wood needed to do such research are disappearing rapidly from a combination of a massive die-off of trees, logging and population pressures, Touchan said.

"We have a chance to do what we call salvage dendrochronology," Touchan said. These are areas where we need to get this information now or it's going to disappear."

Pointing to a cross-section of an old tree from Morocco, he said, "This is from 883 -- and this is from a stump. If we don't take them, they're gone. So this is a real treasure."

The team's paper, "Spatiotemporal drought variability in northwestern Africa over the last nine centuries," is now available online and will be published in a future issue of the journal Climate Dynamics. A complete list of authors and their affiliations is at the bottom of this release. The National Science Foundation funded the research.

The team sampled several different species of conifer and oak trees, because research indicates that testing several different species from the same region provides a better indicator of regional climate.

The current tree-ring chronology builds on previous work in northwest Africa by this team and by other researchers. The chronology incorporates samples from at least 20 trees from each of 39 different sites.

Persistent drought was more widespread across northwest Africa before the year 1500 than for the four centuries following, the researchers found. However, the pattern of widespread regional drought then seems to re-emerge in the late 20th century.

IMAGE: Ramzi Touchan of the University of Arizona's Laboratory of Tree-Ring Research takes a core from an Altas cedar, also known as Cedrus atlantica, in Morocco.

Credit: Photo courtesy of R. Touchan, University of Arizona.



The spatial extent of the new regional tree-ring chronology revealed that drought in Morocco is not driven by the same kinds of oceanic and atmospheric conditions as drought in Algeria and Tunisia.

Drought in Morocco is strongly related to the north/south seesaw of air-pressure anomalies in the North Atlantic Ocean called the North Atlantic Oscillation. However, drought in Morocco is only weakly related to El Nino. By contrast, drought in Algeria and Tunisia appears more linked to a warm tropical Atlantic Ocean.

Touchan hopes to expand the new network's geographic reach to across North Africa, including Libya and additional parts of Algeria.

In addition, he wants to extend the chronology back in time to bridge the gap to archaeological material.

Tree-ring chronologies exist for centuries deep in the past, but they are "floating," meaning that there is no continuous record linking those chronologies to ones that reach back from the present, he said.

"If we can bridge this gap, it will be a discovery for the world," Touchan said.

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Touchan and Meko's co-authors are Kevin J. Anchukaitis of Columbia University's Lamont Doherty Earth Observatory in Palisades, N.Y.; Mohamed Sabir of the National School of Forest Engineering in Sale, Morocco; Said Attalah of the University of Ourgla in Algeria; and Ali Aloui of the Institute of Sylvo-Pastoral of Tabarka in Tunisia.



Study sheds light on how marine animals survive stress

Findings indicate how wildlife responds to environmental and ecological disasters

MEDFORD/SOMERVILLE, Mass. -- For marine iguanas living in the Galapagos Islands, an El Niño can be deadly. Some die from starvation while others survive. Scientists have long believed that the difference between life and death for the iguana depended on the animals' ability to secrete the stress hormone corticosterone.

Under stressful conditions, corticosterone functions like a spigot by controlling how the body expends energy during an emergency. It is associated with the "fight or flight" response to stress and is similar to cortisol in humans. But corticosterone can also be lethal if the spigot is not turned off, according to a study of marine iguanas published in the May 26 online issue of the Proceedings of the Royal Society.

The findings could provide insight into how wildlife in the Gulf of Mexico will respond to the current oil spill. Animals will secrete corticosterone to help them cope with the disaster. However, prolonged hormone production could factor into how well animals are able to survive the crisis.

From 2002 through 2008, a research team led by Tufts University Professor of Biology L. Michael Romero studied corticosterone levels in iguanas on Santa Fe Island before and after the El Niño that struck in late 2002.

The team, funded by the National Science Foundation, included co-author Martin Wikelski from the Max Planck Institute for Ornithology and Konstanz University.

The Galapagos Islands' marine iguanas are a suitable model for study because they live in predictable natural conditions. The animals feed exclusively on marine algae. Their greatest and almost only threat or stress occurs during recurrent El Niño-induced food shortages, when a decrease of algae can lead to starvation.

The scientists captured 98 healthy male iguanas on the island in December 2002, just weeks before the El Niño. They injected a group of the animals with a hormone to stimulate a biological process called negative feedback which lowers the natural corticosterone levels in the animals' blood. The animals responded in one of two ways. Some reacted by shutting shut down the release of corticosterone. In other iguanas, the secretion of corticosterone continued, producing excessive concentrations of the hormone in the blood.

Romero and Wikelski returned to Santa Fe Island in July 2003. Twenty-three of the animals had starved to death, but seventy-five had survived.

According to Romero, the dead iguanas were imperiled by their inability to turn off their stress response. This produced elevated corticosterone levels. In this condition, the animals had depleted the protein reserves that could be processed into energy during a stressful event. In their weakened condition, these iguanas were more susceptible to starvation than their counterparts.

Romero points to several major implications of the findings. First, negative feedback is a vital component of a successful stress response. "The results from the iguanas indicate that the better an individual is at coping with stress -- by turning off the response as soon as possible -- the better the chance they have to survive," he says.

The ultimate goal of the research, says Romero, is "to understand what causes stress in wild animals; what physiological mechanisms are turned on in response to stress and how those mechanisms help the animals survive in their natural habitats."

This work has immediate implications for the current oil spill in the Gulf of Mexico. "As animals encounter the spill, they will have a robust release of corticosterone to help them cope with the consequences of the oil," says Romero. "However, those animals that can best turn off their corticosterone response once the initial danger from the oil has passed will probably be the most likely to survive," he says.

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Tufts University, located on three Massachusetts campuses in Boston, Medford/Somerville, and Grafton, and in Talloires, France, is recognized among the premier research universities in the United States. Tufts enjoys a global reputation for academic excellence and for the preparation of students as leaders in a wide range of professions. A growing number of innovative teaching and research initiatives span all Tufts campuses, and collaboration among the faculty and students in the undergraduate, graduate and professional programs across the university's schools is widely encouraged.

Simple Energy Efficiency Measures Can Eliminate Electricity Shortage in India

Electricity in India can be a dicey proposition. Half the population lacks access or is too poor to afford it. The other half is using so much that demand far outstrips supply, resulting in daily power outages. Businesses and factories rely on diesel or gasoline generators during the brownouts, creating additional pollution. And with a growing middle class buying more TVs, air conditioners and the like, the situation will only get worse.

As chaotic as things are, there is a solution: simple energy efficiency measures, according to a new report from Lawrence Berkeley National Laboratory (Berkeley Lab), can eliminate the electricity deficit as early as 2013. What’s more, doing so will add $505 billion to India’s gross domestic product (GDP) between 2009 and 2017 (compared to India’s total GDP of $911 billion in 2007-2008), as businesses that have had to cut back due to electricity shortages can restore production.

“None of these measures are retrofits; they are all new sales of items such as light bulbs and refrigerators. We tried to keep it as simple as we possibly could—no buildings, no transport,” said report co-author Jayant Sathaye, a Berkeley Lab senior scientist who leads the International Energy Studies Group in the Environmental Energy Technologies Division. “Air conditioners alone are growing at 25% per year in India. But because of this rapid growth, you can capture the new sales, sell only efficient products and make a difference.”

For the report, Sathaye and co-author Arjun Gupta, also of Berkeley Lab, assumed all new sales of some basic appliances would be of energy efficient models, including electric fans, TVs, air conditioners, motors, some industrial processes and water pumps for agriculture; they exclude retrofits of existing technologies. With these steps, they find that the rate of demand growth for electricity declines, allowing the supply to meet and eventually exceed the demand, thus preventing 65 million tons of carbon dioxide emissions by 2017. By 2020, the cumulative benefits increase to $608 billion added to the GDP and 333 million tons of CO2 emissions avoided.

Although some investment would have to be made in energy efficient equipment, the amount is more than offset by the money saved by not building power plants that otherwise would have been needed.

The measures are feasible, Sathaye says, because in fact India has had energy efficiency programs in place in various sectors since at least 2001, when the government passed the Energy Conservation Act, which, among other things, created the Bureau of Energy Efficiency (BEE). “Most developing countries hadn’t done anything like that in 2001,” Sathaye said. “It’s very unique. Neither the U.S. nor China have a bureau dedicated to energy efficiency.”

Berkeley Lab has played a role in India’s energy efficiency programs, working with state regulators and utilities to set up demand-side management programs and working with BEE on building codes and appliance standards and labeling. Currently, four appliances in India, including refrigerators and air conditioners, have mandatory labels with ratings of 1 star (meaning it meets a minimum energy performance standard) to 5 stars (highly efficient). “We look at LBNL as a major resource in providing us policy options and analyses to create an environment that allows people to make energy efficient choices,” said BEE Director Ajay Mathur, who visited Berkeley Lab this month.

Still, the gap between electricity supply and demand continues to grow; India is now importing coal as well as natural gas to keep up with energy consumption. “Energy demand is increasing dramatically due to rising incomes, industrialization, urbanization and population growth,” said Mathur. “The demand will increase by a factor of two over the next 20 years and possibly by three. We’re in a very tight situation.”

Under a new U.S. Department of Energy (DOE) program, and with some technical assistance from Berkeley Lab, India plans to step up its energy efficiency plans by focusing on appliances. Part of a plan announced by Energy Secretary Steven Chu last December in Copenhagen, the Super-efficient Equipment and Appliance Deployment program (SEAD) seeks to introduce highly efficient products at a global scale through various market mechanisms. Recognizing that increased use of lighting and household appliances is estimated to account for more than half of the future growth in electricity consumption worldwide, the U.S. will provide at least $15 million for SEAD over its first five years.

“DOE believes India and the world have much to gain from India’s participation in the SEAD energy efficiency initiative and we look forward to continued collaboration in promoting energy efficiency globally,” said Rick Duke, DOE’s Deputy Assistant Secretary for Climate Policy. “India is an important partner in our efforts to combat climate change and ensure mutual energy security.”

Mathur said India will start by focusing on ceiling fans, then move to TVs and possibly air conditioners. “It’s a powerful mechanism, giving manufacturers incentive to produce super efficient appliances,” said Mathur. “We’ll establish through both technical analysis and market price discovery what kind of incentive needs to be paid, then establish the process for utilities to pay the incentive to the manufacturer.”

Most homes in India have several fans, at least one in each room, and even the poorest homes have at least one fan. (“The first thing people buy when they get electricity is a light and a fan,” said Mathur.) According to Sathaye’s report, efficient fans can offer more than 27% energy savings.

Mathur said Indian consumers are starting to become more energy-conscious. When it comes to buying appliances, efficiency has jumped from the eighth most important factor to the fourth, behind brand, price and color. Politicians are catching on too. “In the last year, I have had five state electricity ministers come to my office, something I have never had happen,” Mathur said.

Berkeley Lab is a U.S. Department of Energy (DOE) national laboratory located in Berkeley, California. It conducts unclassified scientific research and is managed by the University of California for the DOE Office of Science. Visit our website at www.lbl.gov.



Brown Chemists Report Promising Advance in Fuel-Cell Technology

Chemists at Brown University have come up with a promising advance in fuel-cell technology. The team has demonstrated that a nanoparticle with a palladium core and an iron-platinum shell outperforms commercially available pure-platinum catalysts and lasts longer. The finding, reported in the Journal of the American Chemical Society, could move fuel cells a step closer to reality.

PROVIDENCE, R.I. [Brown University] — Creating catalysts that can operate efficiently and last a long time is a big barrier to taking fuel-cell technology from the lab bench to the assembly line. The precious metal platinum has been the choice for many researchers, but platinum has two major downsides: It is expensive, and it breaks down over time in fuel-cell reactions.

In a new study, chemists at Brown University report a promising advance. They have created a unique core and shell nanoparticle that uses far less platinum yet performs more efficiently and lasts longer than commercially available pure-platinum catalysts at the cathode end of fuel-cell reactions.

Metal masters - Vismadeb Mazumder and chemistry professor Shouheng Sun, both of Brown University, have demonstrated that a unique core-shell nanoparticle is a cheaper, more active and longer lasting fuel-cell catalyst than commercially available platinum products
Description : Metal masters - Vismadeb Mazumder (left) and chemistry professor Shouheng Sun, both of Brown University, have demonstrated that a unique core-shell nanoparticle is a cheaper, more active and longer-lasting fuel-cell catalyst than commercially available platinum products.

Photo Credit: Mike Cohea, Brown University







The chemistry known as oxygen reduction reaction takes place at the fuel cell’s cathode, creating water as its only waste, rather than the global-warming carbon dioxide produced by internal combustion systems. The cathode is also where up to 40 percent of a fuel cell’s efficiency is lost, so “this is a crucial step in making fuel cells a more competitive technology with internal combustion engines and batteries,” said Shouheng Sun, professor of chemistry at Brown and co-author of the paper in the Journal of the American Chemical Society.

The research team, which includes Brown graduate student and co-author Vismadeb Mazumder and researchers from Oak Ridge National Laboratory in Tennessee, created a five-nanometer palladium (Pd) core and encircled it with a shell consisting of iron and platinum (FePt). The trick, Mazumder said, was in molding a shell that would retain its shape and require the smallest amount of platinum to pull off an efficient reaction. The team created the iron-platinum shell by decomposing iron pentacarbonyl [Fe(CO)5] and reducing platinum acetylacetonate [Pt(acac)2], a technique Sun first reported in a 2000 Science paper. The result was a shell that uses only 30 percent platinum, although the researchers say they expect they will be able to make thinner shells and use even less platinum.


The multimetallic nanoparticle created by Brown University chemists for fuel-cell reactions uses a palladium core and an iron-platinum shell.
Desription : Less platinum, better efficiency. The multimetallic nanoparticle created by Brown University chemists for fuel-cell reactions uses a palladium core and an iron-platinum shell.

Photo Credit: Sun Lab/Brown University





“If we don’t use iron pentacarbonyl, then the platinum doesn’t form on the (palladium) core,” Mazumder said.

The researchers demonstrated for the first time that they could consistently produce the unique core-shell structures. In laboratory tests, the palladium/iron-platinum nanoparticles generated 12 times more current than commercially available pure-platinum catalysts at the same catalyst weight. The output also remained consistent over 10,000 cycles, at least ten times longer than commercially available platinum models that begin to deteriorate after 1,000 cycles.

The team created iron-platinum shells that varied in width from one to three nanometers. In lab tests, the group found the one-nanometer shells performed best.

“This is a very good demonstration that catalysts with a core and a shell can be made readily in half-gram quantities in the lab, they’re active, and they last,” Mazumder said. “The next step is to scale them up for commercial use, and we are confident we’ll be able to do that.”

Mazumder and Sun are studying why the palladium core increases the catalytic abilities of iron platinum, although they think it has something to do with the transfer of electrons between the core and shell metals. To that end, they are trying to use a chemically more active metal than palladium as the core to confirm the transfer of electrons in the core-shell arrangement and its importance to the catalyst’s function.

Miaofang Chi and Karren More at the Oak Ridge Laboratory also contributed to the paper. The U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy funded the research as part of its Fuel Cell Technologies Program.

Monday, May 24, 2010

Revealing China's ancient past

By Neil Schoenherr



An archeologist at Washington University in St. Louis is helping to reveal for the first time a snapshot of rural life in China during the Han Dynasty.

The rural farming village of Sanyangzhuang was flooded by silt-heavy water from the Yellow River around 2,000 year ago.

Sanyangzhuang tiles set aside to repair a Han house
Working with Chinese colleagues, T.R. Kidder, PhD, professor and chair of anthropology in Arts & Sciences, is working to excavate the site, which offers a exceptionally well-preserved view of daily life in Western China more than 2,000 years ago.

The research was presented at the Society for American Archeology meeting in St. Louis is April and highlighted last month in Science, the journal of the American Association for the Advancement of Science.

“It’s an amazing find,” says Kidder of the site, which was discovered in 2003. “We are literally sitting on a gold mine of archeology that is untapped.”

What researchers find fascinating and surprising, says Kidder, is that the town, though located in a remote section of the Han Dynasty kingdom, appears quite well off.

Exploration has revealed tiled roofs, compounds with brick foundations, eight-meter deep wells lined with bricks, toilets, cart and human foot tracks, roads and trees.

There is an abundance of metal tools, including plow shares, as well as grinding stones and coins. Also found have been fossilized impressions of mulberry leaves, which researchers see as a sign of silk cultivation.

An impression of a mulberry leaf, a sign of silk cultivation, found at the Sanyangzhuang site.

“One could make the argument that this is where the Silk Road began,” Kidder says.

He thinks the site could be substantially larger than is currently known. The flood of sediment that buried the town also covered an area of more than 1,800 square kilometers.

Excavation has revealed two more buried communities beneath Sanyangzhuang. “This sedimentary archive goes to all the way back to the Pleistocene era,” says Kidder, who has experience digging in silt-laden sites near the Mississippi River.

“We have a text written in dirt of environmental change through time that’s associated with the flooding of the Yellow River and it’s environmental relationships. We have an opportunity to examine an entire landscape dating from the Han and periods before,” he says.

Excavated remains of a wall near the site could reveal a walled town, which is still buried in the silt.

Source : http://news.wustl.edu/news/Pages/20805.aspx



Saturday, May 22, 2010

Silica cages help anti-cancer antibodies kill tumors in mice

Honeycombed particles filled with cancer drug act like time-release capsules at tumor site

RICHLAND, Washington – Packaging anti-cancer drugs into particles of chemically modified silica improve the drugs' ability to fight skin cancer in mice, according to new research. Results published May 3 in the Journal of the American Chemical Society online show the honeycombed particles can help anti-cancer antibodies prevent tumor growth and prolong the lives of mice.

"We are very excited by our preliminary results," said biochemist Chenghong Lei of the Department of Energy's Pacific Northwest National Laboratory, part of the team of PNNL and University of Washington scientists. "We plan to do some additional, larger studies with animals. We hope the results hold up well enough to take it to clinical trials somewhere down the road."


Small chemical ornaments (cones) slow the release of anti-cancer antibodies (blue) from this functionalized mesoporous silica (orange).
Small chemical ornaments (cones) slow the release of anti-cancer antibodies (blue) from this functionalized mesoporous silica (orange). Artist's rendering; not to scale. 



Anti-cancer antibodies are some of the most promising types of cancer therapies. The antibodies target a particular protein on cancer cells and — in a poorly understood way — kill off the cells. Examples include herceptin for one form of breast cancer and cetuximab for colon cancer.

Unlike popping a pill, however, antibody-based treatments require patients to go in for intravenous drips into the arm. These sessions cost time and money, and expose healthy tissue to the antibody, causing side effects.

Packaging antibodies into particles would concentrate them at the tumor and possibly reduce side effects. Other research has shown silicon to be well tolerated by cells, animals and people. So, in collaboration with tumor biologist Karl Erik Hellstrom's group at UW, the scientists explored particles made from material called mesoporous silica against cancer in mice.

"The silica's mesoporous nature provides honeycomb-like structures that can pack lots of individual drug molecules," said PNNL material scientist Jun Liu. "We've been exploring the material for our energy and environmental problems, but it seemed like a natural fit for drug delivery."

In previous work, the team created particles that contain nano-sized hexagonal pores that hold antibodies, enzymes or other proteins. In addition, adorning the silica pores with small chemical groups helps trap proteins inside. But not permanently — these proteins slowly leak out like a time-release capsule.

The researchers wanted to test whether anti-cancer antibodies packaged in modified mesoporous silica would be more effective against tumors than free-flowing antibodies.

To do so, they first chemically modified mesoporous silica particles of about six to 12 micrometers (about 1/10 the diameter of human hair). These particles contained pores of about 30 nanometers in diameter. They found that the extent and choice of chemical modification — amine, carboxylic acid or sulfonic acid groups — determined how fast the antibodies leaked out, a property that can be exploited to fine tune particles to different drugs.

Additional biochemical tests showed that the antibodies released from the silica cages appeared to be structurally sound and worked properly.

They then tested the particles in mouse tumors at UW, filling them with an antibody called anti-CTLA4 that fights many cancers, including melanoma, a skin cancer. The team injected these packaged antibodies into mouse tumors. The team also injected antibodies alone or empty particles in other mouse tumors.

The packaged antibodies slowed the growth of tumors the best. Treatment started when tumors were about 27 cubic millimeters. Untreated tumors grew to 200 cubic millimeters about 5 days post-treatment. Tumors treated with antibodies alone reached 200 cubic millimeters on day 9, showing that antibodies do slow tumor growth. But tumors treated with packaged antibodies didn't reach 200 cubic millimeters until day 30, a significant improvement over antibodies alone.

The team repeated the experiment and found the treatment also prolonged the lives of diseased mice. Of five mice that had been treated with particles alone, all died within 21 days after treatment. But of five mice treated with the packaged antibodies, three were still alive at 21 days, and two at 34 days, when the experiment ended.

The team also measured how much antibody remained in the tumors. Two and four days after injection, the researchers found significantly more antibody in tumors when the antibodies had been encased in the silica particles than when the antibodies had been injected alone.

The team is testing other antibody-cancer pairs in mice, especially other cancers that form solid tumors such as breast cancer. They are also going to explore how the antibodies delivered this way induce the immune system to better fight cancer.

"We want to understand the mechanism, because not much is known about how the slowly leaked antibodies induce changes in the immune system or in the micro-environment of the tumor," said Hellstrom.

Reference: Chenghong Lei, Pu Liu, Baowei Chen, Yumeng Mao, Heather Engelmann, Yongsoon Shin, Jade Jaffar, Ingegerd Hellstrom, Jun Liu, Karl Erik Hellstrom, Local release of highly loaded antibodies from functionalized nanoporous support for cancer immunotherapy, May 3, 2010 J. Am. Chem. Soc., DOI 10.1021/ja102414t (http://pubs.acs.org/doi/full/10.1021/ja102414t).

This work was supported by PNNL, Washington Research Foundation, UW Institute of Translational Health Sciences, the NIH, and the U.S. Department of Energy Office of Basic Energy Sciences in the Office of Science.

UW Medicine includes the School of Medicine, Harborview Medical Center, UW Medical Center, Northwest Hospital & Medical Center, UW Medicine Neighborhood Clinics, UW Physicians, Airlift Northwest, and the UW's involvement in the Seattle Cancer Care Alliance. UW Medicine has major academic and service affiliations with Seattle Children's Hospital, Fred Hutchinson Cancer Research Center, and the Veteran's Affairs Puget Sound Health Care System in Seattle and VA Hospital in Boise. The UW School of Medicine is the top public institution in federal funding for biomedical research. Follow us on Twitter - @UWMedicineNews


NASA Sees One of Cyclone Laila's Thunderstorms Almost 11 Miles High

A NASA 3-D look inside Cyclone Laila as it made landfall yesterday revealed a towering thunderstorm reaching almost 11 miles high! NASA's Tropical Rainfall Measuring Mission (TRMM) satellite has been capturing images of Cyclone Laila since it was born in the Northern Indian Ocean as tropical depression 1A earlier this week.

Scientists at NASA can use TRMM data to provide meteorologists a 3-D look at the storm's cloud heights and rainfall, which are extremely helpful in forecasting.

This 3-D image of Cyclone Laila was made using data from TRMM's Precipitation Radar. It shows that the powerful thunderstorms northwest of tropical cyclone Laila shot up to heights above 17.5 kilometers (~57,415 feet, 10.8 miles). Credit: NASA SSAI, Hal Pierce"One of the interesting capabilities of the TRMM satellite is its ability to see through clouds with its Precipitation Radar (PR) and reveal the 3-D structure within storms such as Cyclone Laila," said Hal Pierce, on the TRMM mission team in the Mesoscale Atmospheric Processes Branch at NASA's Goddard Space Flight Center, Greenbelt, Md.

Pierce created a 3-D image of Laila. He used data captured on May 20 when TRMM also got a "top down" view of the storm's rainfall, and created a 3-D image that shows thunderstorm tops reaching to almost 17.5 kilometers (10.8 miles) high in the eastern side of the storm!






Photo Credit : NASA/SSAI, Hal Pierce

Laila brought nine-foot high waves and very heavy rains before it made landfall near the town of Bapatla which lies on the southeast coast of India. The Associated Press reports that 23 deaths have been attributed to the storm. Meanwhile, state officials reported widespread damage, downed trees, power outages, and flooding.

On May 21 at 1200 UTC (8 a.m. EDT), Laila had weakened into a depression as a result of tracking over the rugged terrain of southeastern India. At 8 a.m. EDT Laila's maximum sustained winds had waned to near 38 mph. It was located about 115 nautical miles west-southwest of Visakhapatnam, India and headed in that direction. It was moving north-northeast near 6 mph (5 knots). Widespread heavy rain and gusty winds can be expected from Andhra Pradesh today, and to areas northeast through the weekend as Laila tracks in that direction. For the most recent updates on Laila, go to the India Meteorological Department web site at: www.imd.gov.in/.

The Atmospheric Infrared Sounder instrument on NASA's Aqua satellite captured an image of the waning Laila over southeastern India on May 21 at 3:53 a.m. EDT. The purple indicates remaining strong thunderstorms. Laila is now a depression and is forecast to track in a northeasterly direction over the weekend, bringing moderate to heavy rains to the northeastern coast of India, as it heads to Bangladesh. The Joint Typhoon Warning Center expects Laila's remnants to emerge over the northern Bay of Bengal, intensify slightly and then dissipate before reaching southeastern Bangladesh. Forecasters will be keeping a close eye on the storm over the weekend.







For an Earth Observatory feature on Laila – Tropical Cyclone Laila Soaks India – visit:
earthobservatory.nasa.gov/IOTD/view.php?id=44045&src=imgrss

Text credit: Rob Gutro, NASA's Goddard Space Flight Center
Photo Credit: NASA JPL, Ed Olsen

Developing a better way to detect food allergies

MIT researchers devise new technique that can analyze individual immune cells.

CAMBRIDGE, Mass. — About 30 percent of Americans believe they have food allergies. However, the actual number is far smaller, closer to 5 percent, according to a recent study commissioned by the National Institute of Allergy and Infectious Diseases (NIAID). That’s due in large part to the unreliability of the skin test that doctors commonly use to test for food allergies.

MIT chemical engineer Christopher Love believes he has a better way to diagnose such allergies. His new technology, described in the June 7 issue of the journal Lab on a Chip, can analyze individual immune cells taken from patients, allowing for precise measurement of the cells’ response to allergens such as milk and peanuts.

Using this technology, doctors could one day diagnose food allergies with a simple blood test that would be faster and more reliable than current tests, says Love, an assistant professor of chemical engineering. “With a large number of diagnoses, it’s ambiguous,” he says. “A lot of times it’s almost circumstantial whether you’re allergic to one thing or another.”

The NIAID study, published May 12 in the Journal of the American Medical Association, found that in the United States, 6 to 8 percent of children under four, and 4 percent of people five or older, have at least one food allergy. Milk, peanuts, eggs and soy are among the most common allergens.

Food allergies occur when the body’s immune system mistakes a protein in food for something harmful. This triggers an allergic response that can include rashes, hives, difficulty breathing or gastrointestinal distress. Some allergies can provoke life-threatening anaphylactic shock, which requires immediate treatment.

Patients suspected of having food allergies usually undergo a skin test, which involves placing small quantities of potential allergens under the skin of the patient’s arm. If the patient’s blood has antibodies specific to that allergen, immune cells will release histamines that cause itching and redness in the spot where the allergen was placed.

Doctors can also perform blood tests that directly measure the presence of particular antibodies in the patients’ blood. However, one drawback to both of these tests is that the presence of antibodies to a particular allergen does not necessarily mean that the patient is allergic to that substance, leading to false positive results.

Love’s new technology, developed with funding from the Deshpande Center for Technological Innovation, the Dana Foundation and the NIAID, takes a different approach. Instead of detecting antibodies, his system screens the patient’s immune cells for small proteins known as cytokines. Immune cells such as T cells produce cytokines when an allergic response is initiated, attracting other cells to join in the response.

To perform the test, blood must be drawn from the patient, and white blood cells (which include T cells) are isolated from the sample.

The cells are exposed to a potential allergen and then placed into about 100,000 individual wells arranged in a lattice pattern on a soft rubber surface. Using a technique known as microengraving, the researchers make “prints” of the cytokines produced by each cell onto the surface of a glass slide. The amount of cytokine secreted by each individual cell can be precisely measured. For food-allergy testing, the cytokines of most interest are IL4, IL5 and IL9.

The “gold standard” for diagnosing a food allergy is to see what happens when the patient is given the food in question (in a controlled setting, to ensure safety), but that is not often done outside of allergy research clinics, says Assa’ad.

Love is now working with Dale Umetsu, professor of pediatric immunology at Children’s Hospital Boston, on a project they hope will pinpoint the relationship between cytokine activity and allergic reactions. In that study, children with milk allergies are being given small amounts of milk to desensitize their immune systems to the milk. Using the new technology, the team is tracking how the responses of the patients’ cells change as the patients undergo treatment.

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Written by Anne Trafton, MIT News Office


Related

http://web.mit.edu/lovelab/

http://www.rsc.org/Publishing/Journals/LC/article.asp?doi=b926849a

http://web.mit.edu/newsoffice/2008/vaccination-1103.html

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