C3P0 Science Innovations

Nano-assembly Mimics Origin Of Life? Molecules Organize Themselves Into Patterns

C3P0MU13@yahoo.com — Sun, 25 Nov 2007 18:38:09 GMT

ScienceDaily (Nov. 1, 2007) — The automatic molecular assembly and selection steps exhibited by the molecules, which start as random mixtures, demonstrates a fundamental step in the evolution of life. The organization is activated by instructions which are built-in to the molecules. During assembly, molecules exhibit active selection: those in incorrect positions move to make room for others which fit properly.

The molecular-level observation of such self-selection gives, for the first time, direct insight into fundamental steps of the biological evolution from inanimate molecules to living entities. The resulting nanostructures also hold great promise as an efficient avenue to new catalysts, nanotechnologies, and surface applications.

In the Proceedings of the National Academy of Sciences of the USA, the scientists from the research groups of Klaus Kern at the Max Planck Institute for Solid State Research in Stuttgart (MPI) and of Mario Ruben at the Karlsruhe Institute of Technology (KIT) explain that this observation of molecular organization at surfaces may lead to further insight of how simple, inanimate molecules can build up biological entities of increasing structural and functional complexity, such as membranes, cells, leaves, trees, etc.

"The ability of molecules to selectively sort themselves in highly organized structures is a fundamental requirement for all molecular based systems, including biological organisms," explains Prof. Dr. Klaus Kern, director of the Nanoscale Science Department at the MPI.

Dr. Mario Ruben’s research team at KIT is responsible for designing molecules with built-in instructions, which when read out activate the self-selection process. He comments: "Spontaneous ordering from random mixtures only occurs when built-in instructions are carefully designed and sufficiently strong to initiate successful self-selection."

Scientists at the MPI directly observe the basic step of self-selection by imaging grid-like assemblies of molecules, which have sorted themselves by size. The features of the grid pattern are about one nanometer in size (0.000 000 001 meters), so small that they can only be imaged using state-of-the-art, ultra sensitive microscopy techniques. "Creating such miniscule architectures with features 50 000 times smaller than a hair is not a simple task," according to Dr. Steven Tait of the MPI. "Carving these nanometer structures with current technology would be inefficient and extremely expensive. Our strategy is to utilize instructed building blocks which can arrange themselves into desired structures."

The molecules are placed on ultra-clean metal surfaces and heated gently to enable motion, sorting, and organization. "The molecule movement on the copper surface is restricted to two-dimensions, but is still efficient enough to allow mixing of the molecules. By placing the molecules on a surface, we have the enormous advantage of being able to use specialized microscopes to ‚see’ the nanometer scale structures of the molecular assemblies," explains Alexander Langner, a graduate student at the MPI and first author of the study.

The study was conducted by Alexander Langner, Dr. Steven Tait, Dr. Nian Lin, and Prof. Dr. Klaus Kern of the Max Planck Institute for Solid State Research and Dr. Chandrasekar Rajadurai and Dr. Mario Ruben of the Karlsruhe Institute of Technology (KIT).

Professor Kern is the director of the Nanoscale Science Department at the MPI and leads a large research team conducting a wide range of studies related to the electronic, optical, and chemical properties of novel materials at the nanometer scale. Dr. Ruben is the leader of the research group "Functional Molecular Nanostructures" at the Institute of Nanotechnology in Karlsruhe and has a long-standing competence in the design and synthesis of instructed molecular components.

Adapted from materials provided by Max-Planck-Gesellschaft.

Mystery Probed in Record-Setting Cosmic Explosion

C3P0MU13@yahoo.com — Sun, 25 Nov 2007 18:38:09 GMT

Last September, a supernova burst into a cosmic flame 100 times more intense than any event on record—and left scientists scratching their heads.

Now, two new studies attempt to explain the remarkable explosion. One sets up the explosion with a cannibalistic star, while the other describes how colliding layers of jettisoned gas could outshine all other supernovae.

Researchers from the Netherlands and California detail their theories in today's issue of the journal Nature.

Stellar glutton

Simon Portegies Zwart, an astrophysicist at the University of Amsterdam, said supernova 2006gy's brightness was strange enough. Chemical analysis revealed something weirder.

"It possessed silicon and other heavy materials, which indicates a white dwarf," Portegies Zwart said. But the analysis also turned up hydrogen—a lightweight fuel all but converted into helium in older white dwarf stars. "The combination makes this supernova incredibly strange," he told SPACE.com.

Portegies Zwart thinks a "runaway collision" could form such an oddity; if stuck in a crowded neighborhood, such as the center of a galaxy, an old star could drag in young stellar neighbors and bring hydrogen to the party.

"It would be like a chain collision on the highway. As a large star absorbs smaller ones, it grows more massive and pulls in more stars," he said. A few thousand years after cannibalizing its neighbors, the gluttonous giant would meet its demise as a supernova.

"This would be a rare event. About one in every 6,000 supernova would have similar characteristics," he said.

If the explosion fades in the next year or two, as predicted, Portegies Zwart expects to detect a dense star cluster in its place—and lend support to his team's theory.

Shell shock

Stan Woosley, an astrophysicist at the University of California Santa Cruz, also expects to see a packed stellar neighborhood when the explosion fades.

"These big massive stars are always born in dense clusters," said Woosley, whose team attempts to explain how, exactly, 2006gy burned so brightly.

Stars about 90 to 130 times more massive than the Sun could create the unprecedented supernova as they end up fusing heavy carbon and oxygen atoms for fuel, he said. The process creates sets of annihilating particles, sucking away energy used to push gas outward—and keeping the star from exploding.

But the struggle against gravity eventually fails. When the star explodes, it rockets a shell of 20 suns worth of gas into space at more than 220,000 mph (360,000 kph).

"The star would be massive enough to explode, but not too powerful to unbind itself entirely," Woosley said, noting the event would equal roughly the Sun's entire 10 billion- year energy output in an instant.

Because the star is still intact, however, Woosley said, a second explosion would ensue about seven years later, jettisoning another gas shell at more than 2.2 million mph (3.6 million kph). "When the second, inner envelope catches up, all of that collision energy is turned into light," he said.

What's more, Woosley said, is that another bright outburst could happen again.

"Ordinarily, supernovae happen only once," Woosley said. "Our model indicates it can happen again. If it did, we'd have some pretty definitive proof."

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New Zealand glaciers retreat due to global warming say scientists

C3P0MU13@yahoo.com — Sun, 25 Nov 2007 18:38:09 GMT

WELLINGTON (AFP) — New Zealand's largest glaciers are retreating fast in the face of global warming and could disappear altogether, scientists said Monday.

A report by the National Institute of Water and Atmospheric Research (NIWA) said the volume of ice in New Zealand's Southern Alps had shrunk almost 11 percent in the past 30 years.

More than 90 percent of this loss was because the 12 largest glaciers in the mountain range were melting due to rising temperatures, NIWA said.

The glaciers have passed a threshold, causing the ice to collapse and creating large lakes at their base, the report said.

"The 12 big glaciers with these pro-glacial lakes have passed a tipping point," said NIWA's principal scientist Jim Salinger.

"It is not yet clear whether the glaciers will disappear completely with future warming, but they are set to shrink further as they adjust to today?s climate," he said.

"And it is already clear that they will not return to their earlier lengths without extraordinary cooling of the climate, because the large lakes now block their advance."

Tasman Glacier, the longest in New Zealand, is now about 23 kilometres (14 miles) long. A five-kilometre lake has formed at its base in the past 30 years. In the 1880s, the glacier was 28 kilometres long.

But increased rainfall -- which falls as snow and feeds the higher reaches of the glaciers -- on the western side of the Alps has meant the results for smaller glaciers on that side are mixed, NIWA said.

These ice sheets advanced during most of the 1980s and 1990s amid periods of higher rainfall.

But the best known of these, the Franz Josef glacier, is still much shorter than in 1900 and has retreated about 230 metres (yards) since 2000, despite gains in the past two years, Salinger said.

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Oceans Could Slurp Up Carbon Dioxide To Fight Global Warming

C3P0MU13@yahoo.com — Sun, 25 Nov 2007 18:38:09 GMT

ScienceDaily (Nov. 20, 2007) — Researchers in Massachusetts and Pennsylvania are proposing a new method for reducing global warming that involves building a series of water treatment plants that enhance the ability of the ocean to absorb carbon dioxide from the atmosphere.

About 100 such plants -- which essentially use the ocean as "a giant carbon dioxide collector" -- could cause a 15 percent reduction in emissions over many years, they say. About 700 plants could offset all CO2 emissions.

Scientists believe that excessive build-up of carbon dioxide in the air contributes to global warming. In addition to cutting down on carbon dioxide emissions by reducing the use of fossil fuels, researchers have focused on new technologies that remove the gas directly from the atmosphere.

In the new study, Kurt Zenz House and colleagues propose building hundreds of special water treatment facilities worldwide that would remove hydrochloric acid from the ocean by electrolysis and neutralize the acid through reactions with silicate minerals or rocks.

The reaction increases the alkalinity of the ocean and its ability to absorb carbon dioxide from the atmosphere. The process is similar to the natural weathering reactions that occur among silicate rocks but works at a much faster rate, the researchers say.

The journal article, "Electrochemical Acceleration of Chemical Weathering as an Energetically Feasible Approach to Mitigating Anthropogenic Climate Change," is scheduled to appear in the Dec. 15 issue of ACS' Environmental Science & Technology.

Adapted from materials provided by American Chemical Society.

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