September 21, 2006, 4:59 AM CT

Hidden Messages From Squid Skin

In the animal world, squid are masters of disguise. Pigmented skin cells enable them to camouflage themselves-almost instantaneously-from predators. Squid also produce polarized skin patterns by regulating the iridescence of their skin, possibly creating a "hidden communication channel" visible only to animals that are sensitive to polarized light.

In research published recently in the journal Biology Letters, MBL (Marine Biological Laboratory) scientists Lydia Mäthger and Roger Hanlon present evidence that the polarized aspect of the skin of the longfin inshore squid, Loligo pealeii, is maintained after passing through the pigment cells responsible for camouflage.

While the notion that a few animals produce polarization signals and use them in communication is not new, Mäthger and Hanlon's findings present the first anatomical evidence for a "hidden communication channel" that can remain masked by typical camouflage patterns. Their results suggest that it might be possible for squid to send concealed polarized signals to one other while staying camouflaged to fish or mammalian predators, most of which do not have polarization vision.

Mäthger notes that these messages could contain information regarding the whereabouts of other squid, for example. "Whether signals could also contain information regarding the presence of predators (i.e., a warning signal) is speculation, but it may be possible," she adds.........

Posted by: Ashley      Permalink         Source

September 20, 2006, 9:59 PM CT

Sea Squirts Problem Persisting

Researchers have just completed a field survey of the invasive sea squirt colony on the Georges Bank, first discovered in 2003. A wider area was searched for the sea squirt this year, and it was mapped over about twice the area observed in 2004. Results show that the species is present in two adjacent areas totaling 88 square miles in U.S. waters near the U.S.-Canada boundary. The very large mat-like colonies observed in 2004 have been replaced by fewer smaller ones. The Georges Bank occurrence is the largest known infestation of colonial sea squirts in a major offshore fishing ground.

For the fourth consecutive year, federal and university scientists have surveyed two areas on Georges Bank where an invasive colonial sea squirt continues to thrive on the gravel bottom. The colonies are denser than in 2005 over the 88 square-mile area observed. But researchers found no colonies in nearby Canadian waters, indicating they have not spread eastward. The Georges Bank squirts are a species of the genus Didemnum.

"The area of seabed covered by the colonies has doubled at 75 percent of the sites we observed in both 2005 and 2006," said Dr. Page Valentine of the U.S. Geological Survey, who tracks occurrences of the species off the northeastern U.S., and elsewhere in the world. Greater density of colonies observed during the survey is evidence that the infestation is persistent, and not a short-lived phenomenon.........

Posted by: Ashley      Permalink         Source

September 20, 2006, 9:44 PM CT

The Point Of Icicles

Contemplating some of nature's cool creations is always fun. Now a team of researchers 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 scientists 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 scientists 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. Eventhough other researchers have studied how icicles grow, they had not found a formula to describe their shape.

Surprisingly, the team observed 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.........

Posted by: Kevin      Permalink         Source

September 20, 2006, 9:41 PM CT

White Blood Cells And Transplanted Kidneys

In an example of biological irony, the same white blood cell chemistry known to damage kidneys used for transplants may also help prevent such damage, according to a federally funded study in genetically engineered mice at Johns Hopkins.

Researchers have long known that when blood flow is cut off and then returned to transplanted kidneys or other organs, immune system cells called T lymphocytes produce toxic natural chemicals that contribute to ischemic reperfusion injury (IRI). Nature cannot distinguish between deliberate surgical wounds needed to remove and re-implant a donor kidney and other kinds of organ damage in which certain toxic chemicals are needed to clean up or remove bad tissue.

But in the new study published in the recent issue of The Journal of Immunology, the Hopkins team reports that that T cells can also play a role in reducing cellular damage in IRI kidneys, according to Hamid Rabb, M.D., medical director of kidney and pancreas transplantation at The Johns Hopkins University School of Medicine.

IRI occurs in 30 percent to 40 percent of kidneys removed from dead donors, resulting in lower kidney survival rates, shortened kidney life and a cost increase of approximately $20,000 per patient from the initial hospital stay and treatment alone, according to Rabb. Scientists therefore are interested in identifying means of preventing or rapidly treating IRI, but one barrier to greater understanding has been the inability to detect the lymphocytes in the kidney during the first critical six hours after blood flow is returned.........

Posted by: Sean      Permalink         Source

September 20, 2006, 8:43 PM CT

Thrive After Breast Cancer

Beyond: Live & Thrive After Breast Cancer, a new semi-annual publication from Meredith Special Interest Media, part of the Meredith Corporation (NYSE:MDP) will debut with the Fall/Winter 2006 issue.

The magazine, which provides women who have or had breast cancer the support and latest information on therapy and recovery, hits newsstands September 19, 2006, with a $5.99 cover price.

"Since more than two million American women live with breast cancer, we wanted to provide this community a resource of support, inspiration and hope," says Kelly Kegans, editor of Beyond.

An advisory board of leading experts in the breast cancer field contributed to the premiere issue of Beyond. They include: Susan Brown, the health manager at Susan G. Komen Foundation; Carolyn M. Kaelin, director of Comprehensive Breast Health Center and breast cancer survivor; and Lillie Shockney, Administrative Director at Johns Hopkins Breast Cancer.........

Posted by: Sean      Permalink         Source

September 20, 2006, 8:16 PM CT

Detecting Cancer with Silica Nanoparticles

Using silica nanoparticles labeled with the molecule guanine, researchers at the Pacific Northwest National Laboratory have now created a simple and inexpensive electrochemical method that detects tumor necrosis factor-alpha (TNF-alpha) at clinically useful levels. Moreover, this assay is amenable to miniaturization, suggesting that it could be easily incorporated into a microfluidics-based assay system.

Reporting its work in the journal Analytical Chemistry, a research team headed by Yuehe Lin, Ph.D., loaded guanine molecules onto the surface of silica nanobeads that also contained a chemical anchor known as avidin. They also attached biotin, which binds with extraordinary strength to avidin, to an antibody that binds to the TNF-æ protein. The researchers attached a second antibody, one that binds to a different part of the TNF-æ protein, to a carbon electrode, which functions as the electrochemical sensor.

When TNF-alpha is present in a solution added to the antibody-labeled electrode, it binds to the antibody. Adding the second antibody produces a sandwich around the TNF-alpha molecule. At this point, the researchers then added their labeled silica nanoparticle, which binds to the antibody-TNF-alpha sandwich. In a final step, the scientists added a molecule that reacts with the guanines on the nanoparticle, creating an electrical current that the electrode senses. The current flowing into the electrode is proportional to the amount of TNF-alpha bound to the first antibody. Experiments with this system showed that the limit of detection for the device is approximately 2 picomolar, well within the range needed to detect physiological levels of TNF-alpha.........

Posted by: Sean      Permalink         Source

September 20, 2006, 8:07 PM CT

Infant hominid

The fossilised remains of the child, estimated to have died at the age of three and who was probably a female, shed light on a hotly disputed branch of the human tree known as Australopithecus afarensis.

The best-known A. afarensis is the famous fossil Lucy, recovered in Ethiopia in 1974 and who, for more than 20 years, was the earliest known member of the hominid family.

Hominids are primates who split from apes between five and seven million years ago.

They are considered the forerunners of anatomically modern humans, who appeared on the scene about 200,0000 years ago.

Still unclear, though, is the exact line of geneaology from these small, rather ape-like creatures to the rise of the powerfully-brained H. sapiens.

Once thought by some to be our ancestor, A. afarensis is now widely considered to be a failed branch of the human tree, for a number of experts suspect the hominid was anatomically far closer to apes than humans.........

Posted by: Tyler      Permalink         Source

September 20, 2006, 8:03 PM CT

Droids in the Desert

Image above: In one scenario of the Desert Research and Technology Studies in the Arizona desert, a test subject returns to a mock way station. Credit: NASA
Arizona tourists may think they've stumbled upon a science fiction movie set if they find themselves near the state's famed Meteor Crater in early September.

Though they won't get a glimpse of R2D2 or C3PO, they will see robots, rovers and space suited subjects with the latest interplanetary gear trekking over some of the state's harshest topography.

For two weeks a year, the stark Arizona landscape becomes a surrogate planet for NASA scientists. Why? Well, you can only do so much in a laboratory and it's a long way to Mars.

The temperature extremes, gusty winds and grit and dust of Arizona's high desert make it an ideal location to field test and evaluate prototype planetary exploration gear.

So, now it is exam time for NASA's Desert Research and Technology Studies (RATS), a team of researchers and engineers who test futuristic equipment that may one day be used for explorations of the moon and Mars.

This is the ninth year for Desert RATS to test a variety of advanced prototype equipment and operational concept techniques. The two-week trials will be conducted Sept. 4 -16 on remote field sites near the crater.

"Field tests like these are much like a final exam," said Johnson Space Center's Joe Kosmo, who leads the team. "We know what works on paper or in the laboratory, but what works there may not work in the field, or it may work differently than expected. Field testing offers a hands-on experience base that is important as we strive to design and operate these emerging planetary surface technologies."........

Posted by: Tyler      Permalink         Source

September 20, 2006, 5:13 AM CT

Ceramic microreactors for on-site hydrogen production

Researchers 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 correlation 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 prior work, Kenis and his 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 scientists 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 scientists also demonstrated the successful decomposition of ammonia at temperatures up to 1,000 degrees Celsius.........

Posted by: Sarah      Permalink         Source

September 19, 2006, 9:24 PM CT

Evolution at fast pace In The Island

The restricted scale, isolation, and sharp boundaries of islands create unique selective pressures, often to dramatic effect. Following what's known as the "island rule," small animals evolve into outsize versions of their continental counterparts while large animals shrink.

Giant tortoises and iguanas still inhabit the Galápagos and a few other remote islands today, but only fossils remain of the dwarf hippopotami, elephants, and deer that once lived on islands in Indonesia, the Mediterranean, and the Pacific Ocean. The fossil record suggests that these size changes occur rapidly after species become isolated on islands, but this long standing assumption has never been empirically examined in a systematic manner. Now, in a new study published in PLoS Biology, Virginie Millien confirms that island species undergo accelerated evolutionary changes over relatively short time frames, between decades and several thousand years.

Millien collected data from text, figures, and tables in an extensive survey of the published literature. From these datasets, she calculated a total of 826 evolutionary rates for 170 populations representing 88 species. Rates of evolutionary change, she found, decreased over time for both island and mainland species, with a slower rate of decrease for island species. The differences in evolutionary rates between island and mainland pairs also decreased over time, becoming statistically insignificant for intervals over 45,000 years. Overall, island species evolved faster than mainland species--a phenomenon that was most pronounced for intervals between 21 years through 20,000 years.........

Posted by: Ashley      Permalink         Source