Memory Molecule

Scientists Find Memory Molecule from PhysOrg.com

In an article in Science magazine, SUNY Downstate researchers describe erasing memory from the brain by targeting a molecular mechanism that controls memory. Finding may be applied to chronic pain, memory loss, and other conditions.

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Nanowire arrays

Nanowire arrays can detect signals along individual neurons from PhysOrg.com

Opening a whole new interface between nanotechnology and neuroscience, scientists at Harvard University have used slender silicon nanowires to detect, stimulate, and inhibit nerve signals along the axons and dendrites of live mammalian neurons.

[...]

Nanocomposite Materials

Nanoscience May Produce "Perfect" Materials

Nanoscience may provide a way to engineer materials that are virtually defect-free – perfect, that is.

A scientist at North Carolina State University has discovered that the tiny grains comprising many bulk materials can potentially contain nearly zero structural imperfections when the grains are smaller than a certain critical size, typically a few to several nanometers.

Therefore, materials created with grains of the right size could be structurally flawless. Not only would these materials possess exceptional strength and durablity, but their optical, electrical, and magnetic properties could be vastly improved as well. The number of potential applications, such as smart sensors and ultra-efficient “solid-state” lighting, as well as entire industries impacted, such as automobiles and defense, is staggering.

“Nanostructured materials offer a unique opportunity to realize perfect materials with greatly improved properties,” said NCSU materials scientist Jagdish (Jay) Narayan, the study's sole researcher, to PhysOrg.com. “Copper, for example, can be made as strong as steel by reducing the grain/feature size so that defects cease to exist.”

In his paper describing the work, published in the August 7 online edition of the Journal of Applied Physics, Narayan discusses the many types of defects that can be present in a material and shows, via theoretical arguments and a couple of specific examples, how controlling grain size may be able to prevent them.

For example, one type of defect is a dislocation, an irregularity in the repetitive pattern of a crystalline material that compromises strength. It is nearly impossible to eliminate dislocations, Narayan says, but reducing the grain size can theoretically restrict the movement of a dislocation so that it can't propagate through the rest of the material. For copper, he calculates that this will occur at the critical grain size of about 7.5 nanometers (nm).

He provides a specific example of how grain size affects a material's properties, using a nanocomposite material made of two compounds, tungsten carbide (WC) and nickel aluminide (NiAl). The NiAl component acts as a hardening agent, bonding with atoms at the surface of WC nanoparticles. Because WC-NiAl grains are all about the same size, it is a good material for testing how grain size affects hardness. The results show the hardness of WC-NiAl increases as its grain size decreases, but only down to a critical grain size. Below that, the material begins to get softer.

But there are some challenges to overcome before a “perfect” material could truly be achieved. The problems lie at the interfaces between grains, where the surfaces of two grains meet. There, some defects may persist because it is difficult for scientists to control certain properties and grain-to-grain interactions, such as atomic structure, chemistry, and atomic bonding.

Just how difficult is determined by the ratio of surface atoms to inner-grain atoms. As grain size gets smaller, this ratio gets larger – there are more and more surface atoms relative to non-surface atoms. Through additional research, scientists may be able to make adjacent grains come together harmoniously and prevent defects between them.

Citation: Journal of Applied Physics, Volume 100, 0034039 (2006)

By Laura Mgrdichian, Copyright 2006 PhysOrg.com

Wally Wood's 22 Panels That Always Work

The essential reference for any comics illustrator and writer, now available in a clean scan of its original courtesy Joel Johnson.

'Lost' fishermen adrift 9 months

Aug. 17, 2006. 07:02 AM

HECTOR TOBAR

SPECIAL TO THE STAR

MEXICO CITY - Lost at sea since October, the three fishermen from a hamlet outside San Blas were given up for dead long ago.

After weeks of looking for their son at fishing ports up and down the Pacific coast of Mexico, the parents of Salvador "Chava" Ordonez resigned themselves to the belief that he, his two companions and their 10-metre fishing boat had been swallowed up by the sea, family members said.

On Tuesday, news of a miracle came from more than 8,000 kilometres away. After more than nine months adrift, Ordonez and his companions had been found alive north of Baker Island in the central Pacific, the lonely stretch of ocean where aviator Amelia Earhart disappeared almost 70 years ago. They were rescued a week ago by a Taiwanese fishing trawler.

Sunburned, skinny, but healthy, they were rescued Aug. 9 by the crew of the Koo's 102, a Marshall Islands fishing boat run by a Taiwanese crew. Trade winds and currents had carried the three from the waters off their home state of Nayarit more than halfway to Australia.

"They were quite hungry," Eugene Muller, manager of Koo's Fishing Co., said from the Marshall Islands. "It's a long ways from Mexico to here."

The Mexicans' fishing boat had two disabled outboard motors but was still seaworthy, he said.

Interviewed Tuesday evening via shipboard radio by Mexican television, the men said they survived by eating raw fish and capturing seabirds.

"Sometimes our stomachs would hurt, because we would go up to 15 days without eating," Jesus Eduardo Vidana told Televisa. "There were times when we had only one bird to share among the three of us."

They apparently had no radio or cellphone, relatives said. But they carried several days' worth of water and food, including a supply of lemons.

Ordonez, Vidana and Lucio Rendon left the hamlet of El Limon on Oct. 28, for what was to have been two or three weeks of deep-sea fishing.

LOS ANGELES TIMES

Link

Evolution Reversed In Mice

From BBC News

By engineering its genetic blueprint, they have rebuilt a gene that was present in primitive animals.

The ancient gene later mutated and split, giving rise to a pair of genes that play a key role in brain development in modern mammals.

The scientists say the experiments shed light on how evolution works and could lead to new gene therapy techniques.

"We are first to reconstruct an ancient gene," said co-researcher Petr Tvrdik of the University of Utah. "We have proven that from two specialised modern genes, we can reconstruct the ancient gene they split off from.

"It illuminates the mechanisms and processes that evolution uses, and tells us more about how Mother Nature engineers life."

Brain development

The study, published in the academic journal Developmental Cell, involved a suite of genes involved in embryonic development.

Until about 500 million years ago, early animals had 13 such Hox genes. Then each gene split into four, making 52 genes.

Over the course of evolution, further mutations occurred, and some genes became redundant and disappeared, leading to today's tally in mammals of 39 Hox genes.

The Utah team looked at two of these genes; Hoxa1, which controls embryonic brain development, and Hoxb1, which plays a key role in the development of nerve cells that control facial expressions in animals.

Hybrid gene

The Utah pair combined critical sections of each gene, reconstructing a gene similar to its equivalent some 530 million years ago.

The hybrid gene is not completely identical to the ancient one, but the scientists say it performs essentially the same functions.

"What we have done is essentially go back in time to when Hox1 did what Hoxa1 and Hoxb1 do today," said Mario Capecchi, professor of human genetics at the University of Utah School of Medicine.

"It gives a real example of how evolution works because we can reverse it."

(Thanks to Chrissy Aitchison for this)

Unearthing ET

Unearthing ET?

A U of T professor digs for micro-organisms two kilometres deep in Timmins
Her work could yield the secret of life on other planets, Anna Piekarski reports

Aug. 3, 2006. 01:00 AM

ANNA PIEKARSKI

STAFF REPORTER

Rather than looking into deep space, a University of Toronto professor has taken the search for the secret of alien life to the depths of a Timmins mine.

Geologist Barbara Sherwood Lollar has received funding from NASA and the Canadian Space Agency to study how life might exist on other planets, but she believes the secret may be found underground.

"What they are interested in is the area of extraterrestrial life," Sherwood Lollar says. "We study the Earth to understand what it might mean for the exploration of other planets."

Sherwood Lollar's research takes her two kilometres below the Earth's surface, where she collects water samples from cracks in the rock. There is life in the water — microbes that could hold the clue to survival on other planets.

It was often thought that nothing could live deep underground. Plants need photosynthesis, a process that requires the sun, and other organisms eat the plants to get energy, Sherwood Lollar notes. These microbes are able to survive without sunlight — a trait they might share with life forms in space.

"NASA and the Canadian Space Agency believe that if they find life on other planets, it will look like this," she says.

Microbes are minute living beings, too small to be seen by the human eye. Bacteria are a common type of microbe, also known as a micro-organism.

The water running through the cracks in the rocks of the copper and zinc mine in Timmins is 10 times more salty than seawater because it has been interacting with the rocks for up to 3 billion years. This groundwater makes a delicious beverage that is a favourite of microbes. "Microbes aren't stupid, they're going for the jelly doughnut every time," and turning the hydrogen in the water into energy, Sherwood Lollar says.The water also contains methane — a gas that is found on Mars. Sherwood Lollar studies the amount of gas in the water — gases produced by the microbes.

Methane found in the atmosphere of Mars may have been produced by microbes, suggesting there could be life on the red planet, says Martin Lebeuf, a manager of space sciences at the Canadian Space Agency.

NASA reports the average surface temperature on Mars is -53C. Due to the cold conditions water cannot remain in a liquid state, but it may exist below the surface, Lebeuf says. It is thought that microbes can live below the surface of Mars at points where the ice goes deep enough to be warmed by magma, a hot fluid or semi-liquid material that erupts as lava. Atmospheric radar will be used by NASA to find spots where the ice and magma meet.

"It is exciting because this is essentially a sort of rehearsal for what scientists will some day do on Mars, either robotically or in person," Lebeuf says in an email from the remote Haughton Mars Project Research Station in Nunavut where he's working. "This work will ultimately help to answer the fundamental question, `Are we alone in the universe?'"

The Kidd Creek mine in Timmins is a perfect place to study this phenomenon, notes Sherwood Lollar, because the mineshaft allows relatively easy access to the underground water. She's quick to credit staff at Kidd Creek who have been very accommodating in granting her access to the mine, where she's been conducting research throughout her 10 years at the U of T. Sherwood Lollar notes that, without the co-operation of mine workers, it would be almost impossible to conduct this type of study, since there is no other way to get access to rocks two kilometres underground.

She and her team of researchers also have been studying a mine in Thompson, Man., in their overall project, which has been funded by NASA since 2004 and was given a boost this spring from a Canadian Space Agency grant.

Mines in New Zealand, Finland and South Africa also have been used, but the Canadian Shield is an ideal Petri dish.

"Canada is a perfect place to conduct this research," Sherwood Lollar says.

"The world is coming here to do science.

"This contribution could give Canada a more active role in space missions. Sherwood Lollar, for example, has been participating in planning for future missions to Mars.

Lebeuf is also excited about the potential that Sherwood Lollar's research holds for science in this country. When international organizations such as NASA fund Canadian projects and come here to study, it allows the country to showcase what it can offer to the investigation of space.

"Ultimately, this may help to position Canada as a major player in future international exploration missions to Mars and elsewhere," Lebeuf says.

We Are The Sum Of Our Parasites

A Nation of Neurotics? Blame The Puppet Masters?

Once again, I hear the siren song of Toxoplasma, the parasite that dwells in the brains of 50 million Americans.

Toxoplasma gondii is an extraordinary creature, whose exploits I've chronicled in previous posts , an article in the New York Times and my book Parasite Rex. This single-celled organism has a life cycle that takes it from cats to other mammals and birds and back to cats again. Studies have shown that the parasite can alter the behavior of rats, robbing them of their normal fear of cats--and presumably making it easier for the parasites to get into their next host.

Toxoplasma is astonishingly successful, able to live in thousands of species, including us. Billions of people are infected with Toxoplasma, which they pick up from the soil or from contaminated meat or water. In most people it remains dormant, but even in this quiet state it may also have affect human behavior. Some scientists have linked Toxoplasma to schizophrenia, while others have found personality differences between people with Toxoplasma and those who are Toxo-free. It's possible that it uses its prey-altering strategy on our brains, too.

All well and good. But now Toxplasma is going big time. Today the Proceedings of the Royal Society of London is publishing a paper called, "Can the common brain parasite, Toxoplasma gondii, influence human culture?"

The paper's answer? Quite possibly yes. Here's why...

The author of the study is Kevin Lafferty, a biologist at the University of California at Santa Barbara. Lafferty made three straightforward observations.

1. Toxoplasma infection rates vary from country to country. South Korea has prevalance rate of only 4.3%, for example, while Brazil's rate is 66.9%. These rates are determined by many factors, from the eating habits in a country (steak tartar, anyone?) to its climate (Toxoplasma oocysts survive longer in warm tropical soil).

2. Psychologists have measured some of the personality traits influenced by Toxoplasma in these countries. People with Toxoplasma tend to be more self-doubting and insecure, among other things. Among the differences in men, Toxoplasma is associated with less interest in seeking novelty. Toxoplasma-infected women are more open-hearted.

3. A nation's culture can be described, at least in part, as the aggregation of its members' personalities. Here's a paper with more background (abstract, pdf)

So Lafferty wondered, is there a relationship between a country's prevalence of Toxoplasma and its culture?

The answer, he argues, is yes. He selected a few key features of human personality that Toxoplasma appears to influence, and which have been measured on a national scale--such as neuroticism, uncertainty avoidance, and "masculine" sex roles. Lafferty predicted that in countries with higher Toxoplasma rates, these features would all be stronger. He gathered data from studies on 39 countries in from all five continents. He corrected for various factors, for example including per capita gross domestic product as a variable. He found a signficiant correlation between high levels of the parasite and high levels of neuroticism. There was a positive but weak correlation between Toxoplasma and levels of uncertainty avoidances and masculine sex roles. However, if he excluded the non-Western countries of China, South Korea, Japan, Turkey, and Indonesia, the correlations of both personality measurements with Toxoplasma got much stronger.

So--has Lafferty discovered why the French are neurotic (Toxo: 45%) and Australians are not (28%)? As he admits, this is just a first pass. A number of countries--particularly from Africa--are missing from the analysis. I'd also wonder how Lafferty could take into account the fact that Toxoplasma rates have probably been changing over the decades. Scientists I've spoken to suspect it is falling in the United States, thanks to better handling of meat. But since Toxoplasma can infect people for decades, a simple measurement of prevalence may miss a steady decline. Are Americans becoming less neurotic?

Lafferty also notes that many other factors shape a nation's culture--which actually raises another interesting question: what about other parasites? Do viruses, intestinal worms, and other pathogens that can linger in the body for decades have their own influence on human personality? How much is the national spirit the spirit of a nation's parasites?

Enquiring (and possibly parasite-harboring) minds want to know.