September 20, 2006, 10:08 PM CT

Obesity Crisis in Insects?

Ever seen a fat insect? Probably not. Dr. Spencer Behmer may have the answer why, and that could have implications for what is billed as the current human obesity epidemic.

Behmer, an entomologist with the Texas Agricultural Experiment Station, and several other researchers conducted a series of experiments to find out whether caterpillars could adapt to extreme changes in their nutritional environment.

By manipulating the nutritional environment of the diamondback moth caterpillars, the researchers found that the insects evolved different physiological mechanisms related to fat metabolism. Which mechanism was used depended on whether the caterpillars were given carbohydrate-rich or carbohydrate-poor food.

The team's work was published recently in the Proceedings of the National Academy of Science.

The researchers theorized caterpillars - and animals in general - can evolve metabolically to adjust to extreme nutritional environments.

All animals need carbohydrates for energy and protein to build muscle and tissue, Behmer said. Different animals, however, need different amounts of these two macronutrients and sometimes it can be literally feast or famine for one or both of them.

"It's difficult to find in any environment a nutritionally perfect food," he said.........

Posted by: Beverly      Permalink         Source

September 20, 2006, 9:55 PM CT

Skeletal Microdamage Stable After First Year

Skeletal microdamage resulting from bisphosphonate treatment may be maximal during the first year of treatment, and not continue to accumulate with longer periods of treatment, according to new research being presented today at the 28th Annual Meeting of the American Society for Bone and Mineral Research (ASBMR).

Bisphosphonates are the most common class of drugs used for the treatment of osteoporosis because of their demonstrated effect on fracture reduction but the incidence of microcracks - small cracks in the skeleton - has been shown to increase with bisphosphonate treatment. This has led to some concerns regarding the potential long-term adverse effects of these agents. This study shows that the continued use of alendronate (a bisphosphonate) is not associated with continued accumulation of microdamage.

Matt R. Allen, Ph.D., assistant research professor, and David B. Burr, Ph.D., chairman, both from the Indiana University School of Medicine Department of Anatomy and Cell Biology, Indianapolis, IN, evaluated the effects of alendronate in one-year-old female beagles. The beagles were given oral doses of alendronate at levels comparable to that employed in humans (.2 mg/kg/day) or at five times the clinical dose (1 mg/kg/day) for either 1 year or 3 years.........

Posted by: Beverly      Permalink         Source

September 20, 2006, 9:45 PM CT

The Point Of Icicles

Contemplating some of nature's cool creations is always fun. Now a team of scientists from The University of Arizona in Tucson has figured out the physics of how drips of icy water can swell into the skinny spikes known as icicles.

Deciphering patterns in nature is a specialty of UA researchers Martin B. Short, James C. Baygents and Raymond E. Goldstein. In 2005, the team figured out that stalactites, the formations that hang from the ceilings of caves, have a unique underlying shape described by a strikingly simple mathematical equation.

However, stalactites aren't the only natural formations that look like elongated carrots. Once the researchers had found a mathematical representation of the stalactite's shape, they began to wonder if the solution applied to other similarly shaped natural formations caused by dripping water.

So the team decided to investigate icicles. Although other scientists have studied how icicles grow, they had not found a formula to describe their shape.

Surprisingly, the team found that the same mathematical formula that describes the shape of stalactites also describes the shape of icicles.

"Everyone knows what an icicle is and what it looks like, so this research is very accessible. I think it is amazing that science and math can explain something like this so well. It really highlights the beauty of nature," Short said.........

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September 20, 2006, 5:13 AM CT

Ceramic microreactors for on-site hydrogen production

Scientists at the University of Illinois at Urbana-Champaign have designed and built ceramic microreactors for the on-site reforming of hydrocarbon fuels, such as propane, into hydrogen for use in fuel cells and other portable power sources.

Applications include power supplies for small appliances and laptop computers, and on-site rechargers for battery packs used by the military.

"The catalytic reforming of hydrocarbon fuels offers a nice solution to supplying hydrogen to fuel cells while avoiding safety and storage issues related to gaseous hydrogen," said Paul Kenis, a professor of chemical and biomolecular engineering at Illinois and corresponding author of a paper accepted for publication in the journal Lab on a Chip, and posted on its Web site.

In previous work, Kenis and colleagues developed an integrated catalyst structure and placed it inside a stainless steel housing, where it successfully stripped hydrogen from ammonia at temperatures up to 500 degrees Celsius.

In their latest work, the researchers incorporated the catalyst structure within a ceramic housing, which enabled the steam reforming of propane at operating temperatures up to 1,000 degrees Celsius. Using the new ceramic housing, the researchers also demonstrated the successful decomposition of ammonia at temperatures up to 1,000 degrees Celsius.........

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September 19, 2006, 9:02 PM CT

Shocking Scenes From Antarctica

Observing data from Envisat's Advanced Synthetic Aperture Radar (ASAR) instrument and the AMSR-E instrument aboard the EOS Aqua satellite, scientists were able to determine that around 5-10 percent of the Arctic's perennial sea ice, which had survived the summer melt season, has been fragmented by late summer storms. The area between Spitzbergen, the North Pole and Severnaya Zemlya is confirmed by AMSR-E to have had much lower ice concentrations than witnessed during earlier years.

Satellite images acquired from 23 to 25 August 2006 have shown for the first time dramatic openings - over a geographic extent larger than the size of the British Isles - in the Arctic's perennial sea ice pack north of Svalbard, and extending into the Russian Arctic all the way to the North Pole.

Mark Drinkwater of ESA's Oceans/Ice Unit said: "This situation is unlike anything observed in previous record low ice seasons. It is highly imaginable that a ship could have passed from Spitzbergen or Northern Siberia through what is normally pack ice to reach the North Pole without difficulty.

"If this anomaly trend continues, the North-East Passage or 'Northern Sea Route' between Europe and Asia will be open over longer intervals of time, and it is conceivable we might see attempts at sailing around the world directly across the summer Arctic Ocean within the next 10-20 years".........

Posted by: Beverly      Permalink         Source

September 19, 2006, 5:09 AM CT

Monitoring Coastal Ocean Pollution

Public health officials now may be able to know instantly when pollution has moved into the coastal ocean - a breakthrough that could enable authorities to post warnings or close beaches in minutes rather than days thanks to research by UC Irvine researchers.

The new technique analyzes temperature and salinity data collected by sensors located in the water along the Southern California coast. Scientists observed that fluctuations in the sensor data correlate with changes in water quality as soon as they occur. This type of analysis may lead to detection methods that are far faster than the current method of physically collecting water and testing it in a lab.

"Decisions to post a warning or close a beach are currently made one to three days after a sample is collected. This would be fine if you were testing water that sits in a tub, but ocean currents are highly dynamic, and water quality varies hour by hour and minute to minute," said Stanley B. Grant, professor of chemical engineering and materials science at UCI. "Our research shows that near real-time sensor data can be used to detect changes in the state of the coastal ocean - information that could, in concert with traditional monitoring data and new ocean observing systems, eventually result in the creation of an up-to-the-minute water-quality report accessible by the public on the Internet".........

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September 18, 2006, 9:36 PM CT

Metal deformation studies

By combining very large-scale molecular dynamics simulations with time-resolved data from laser experiments of shock wave propagation through specific metals, researchers at the Lawrence Livermore National Laboratory are now able to better understand the evolution of high-strain-rate plasticity.

Plastic deformation of metals results from the motion of a high density of dislocation lines. A strong shock produces an unusual number of dislocations within a metal's crystalline lattice, which changes the metal's mechanical properties such as strength, ductility and resistance to fracture and cracking.

In a paper reported in the Sept. 17 edition of the journal Nature Materials, Livermore researchers, in conjunction with researchers from the University of Oxford, have compared and validated strong shock molecular dynamics simulations to dynamic experimental data in metals.

"We calculated the time needed for the metal to generate defects and relax in a strong shock wave," said Eduardo Bringa, LLNL's lead author of the paper. "We came to understand this time interval in terms of the time needed for line defects (dislocations) to move far enough to relax the strain. It was known that the more dislocations that are produced and the more they move, the more the strain is relaxed".........

Posted by: Ethen      Permalink         Source

September 18, 2006, 9:21 PM CT

Engine On A Chip Would Be Best The Battery

MIT researchers are putting a tiny gas-turbine engine inside a silicon chip about the size of a quarter. The resulting device could run 10 times longer than a battery of the same weight can, powering laptops, cell phones, radios and other electronic devices.

It could also dramatically lighten the load for people who can't connect to a power grid, including soldiers who now must carry many pounds of batteries for a three-day mission -- all at a reasonable price.

The researchers say that in the long term, mass-production could bring the per-unit cost of power from microengines close to that for power from today's large gas-turbine power plants.

Making things tiny is all the rage. The field -- called microelectromechanical systems, or MEMS -- grew out of the computer industry's stunning success in developing and using micro technologies. "Forty years ago, a computer filled up a whole building," said Professor Alan Epstein of the Department of Aeronautics and Astronautics. "Now we all have microcomputers on our desks and inside our thermostats and our watches".

While others are making miniature devices ranging from biological sensors to chemical processors, Epstein and a team of 20 faculty, staff and students are looking to make power -- personal power. "Big gas-turbine engines can power a city, but a little one could 'power' a person," said Epstein, whose colleagues are spread among MIT's Gas Turbine Laboratory, Microsystems Technology Laboratories, and Laboratory for Electromagnetic and Electronic Systems.........

Posted by: Beverly      Permalink         Source

September 18, 2006, 6:38 PM CT

Fish That Can Walk

There are a number of more species to be discovered under the sea. Scientists examining the undersea fauna off Indonesia's Papua province said Monday they had discovered dozens of new species, including a shark that walks on its fins and a shrimp that looks like a praying mantis.

"It's one of the most stunningly beautiful landscapes and seascapes on the planet," said Mark Erdmann, a senior adviser of Conservation International who led two surveys to the area earlier this year.

"Above and below water, it's simply mind blowing," he said.........

Posted by: Beverly      Permalink         Source

September 17, 2006, 10:18 PM CT

Supporting Industrial Zeolites

The National Institute of Standards and Technology (NIST) has issued three new reference materials to support researchers studying the properties of commercially important zeolites.

First described in the 18th century, zeolites have seen increasing use in industry and commerce from cat litter to industrial catalysts and "molecular sieves." Zeolites belong to class of materials called alumino-silicates whose crystal structures form highly porous, nanoscale "cages" that can filter and trap small molecules. Naturally occurring zeolites are mined and widely used as absorbents in products such as cat litter. Tailored synthetic zeolites have a wide variety of more specialized applications, such as in laundry detergents (where they replace pollution-causing phosphates), and as catalysts in oil refineries. Because they can be designed with pores that pass only molecules of a certain size and shape, zeolites have excited considerable interest as molecular sieves for chemical separations--they are used in oxygen generation systems for medical oxygen, for example.

It is often extremely difficult to make precision measurements of key chemical characteristics for zeolites because they are ferociously hygroscopic. Humidity must be precisely controlled--and specified--to make meaningful measurements of the elemental content, for example. This has made it difficult to compare experimental results between different labs.........

Posted by: Beverly      Permalink         Source