November 18, 2006

Regeneration of chickens too

Mice were made to regenerate and now chickens can regenerate as well

By changing the expression of a few genes, you can change the ability of a vertebrate to regenerate their limbs, rebuilding blood vessels, bone, muscles, and skin - everything that is needed. The study, published in the advance online edition of Genes and Development on Nov. 17, demonstrates that vertebrate regeneration is under the control of the powerful Wnt signaling system: Activating it overcomes the mysterious barrier to regeneration in animals like chicks that can't normally replace missing limbs while inactivating it in animals known to be able to regenerate their limbs (frogs, zebrafish, and salamanders) shuts down their ability to replace missing legs and tails.

The procedure was tricky, however. Belmonte noted that if Wnt signaling is activated for too long of a period in these animals, cancer results. "This has to be done in a controlled way, with just a few cells for a specific amount of time," he says. "The fact is that this pathway is involved in cell proliferation, whether it is to generate or regenerate limbs, control stem cells, or produce cancer."

Perhaps the recently found RNA activation process for triggering genes could be used to help turn on the Wnt genes and the RNA interference can be used to turn it off.

Fiction: Babylon 5 the lost tales coming to DVD

Two movies set in the Babylon 5 universe will be sold on DVD and are filming now.

There were originally three mini-movies featuring Sheridan, Lochley, Galen and Garibaldi. However, the Garibaldi one has been pushed to the next DVD (assuming sales are good for this one).

The effects and the look of the shows will be updated with the latest technology.

Growth of nanotubes from nanoseeds could allow mass production of pure types of tubes

Rice University chemists today revealed the first method for cutting carbon nanotubes into "seeds" and using those seeds to sprout new nanotubes. The findings offer hope that seeded growth may one day produce the large quantities of pure nanotubes needed for dozens of materials applications.

There are dozens of types of SWNTs, each with a characteristic atomic arrangement. These variations, though slight, can lead to drastically different properties: Some nanotubes are like metals, and others are semiconductors. While materials scientists are anxious to use SWNTs in everything from bacteria-sized computer chips to geostationary space elevators, most applications require pure compounds. Since all nanotube production methods, including the industrial-scale system Smalley invented in the 1990s, create a variety of 80-odd types, the challenge of making mass quantities of pure tubes – which Smalley referred to as "SWNT amplification" – is one of the major, unachieved goals of nanoscience.

The nanotube seeds are about 200 nanometers long and one nanometer wide – length-to-diameter dimensions roughly equal to a 16-foot garden house. After cutting, the seeds underwent a series of chemical modifications. Bits of iron were attached at each end, and a polymer wrapper was added that allowed the seeds to stick to a smooth piece of silicon oxide. After burning away the polymer and impurities, the seeds were placed inside a pressure-controlled furnace filled with ethylene gas. With the iron acting as a catalyst, the seeds grew spontaneously from both ends, growing to more than 30 times their initial length – imagine that 16-foot water hose growing by more than 500 feet – in just a few minutes

November 17, 2006

resveratrol and Sirtuin activators

Resveratrol helps protect against the diseases of obesity and at higher doses helps to double endurance in mice

Dr. Sinclair dosed his mice daily with 22 milligrams of resveratrol for each kilogram of weight to protect them from the diseases of obesity. For an 80 kilogram man that would be 1.7 grams per day. Currently 40mg capsules are made by Longevinex and other companies.

Dr. Auwerx used up to 400 milligrams per kg of weight protected the mice from gaining weight and from developing metabolic syndrome, doubled their endurance, gave them muscle fibers like an athletic mouse and increased lifespan by 30%. An 80 kg man would need 32 grams per day (3.2 CCs in pure form). A 50kg woman would need 20 grams per day.

It is believed that resveratrol activates the Sirtuin genes.

Wikipedia has information on the seven genes in the Sirtuin family

RNA activiation could be a more direct route to activating the Sirtuin genes RNA activation is a newly discovered technique that still needs to be better understood and perfected.

If one had a model of a candidate persons genome (In 10 years perhaps $1000 to sequence one persons genome) and knew more about what different genes did and then ran simulations to determine the optimal expression and suppression of those genes...I believe the result would be unlocking vastly superior athletic, intellectual performance, immune systems and longevity. If the early stage result is something approaching what we have done in mice then a fully optimized expression could be several times better.

Activation of the Wnt genes could enable regeneration in humans

Gene therapy history and future

8 web page article that tracks the history, hurdles and promise of gene therapy from decades past to the slow steady progress of today

Several areas of progress are converging to realize the dream of control of our genes and bodies proteins.

1. Better microscopic and nanoscale tools for imaging and tracking what is happening at the cellular and molecular level in real time. This helps us to understand what is really happening at the scales where activity is occuring. More and more analysis that used to take weeks is now happening in a minute or less.
2. More and cheaper computing power to analyze and model all of that nanoscale information.
3. Gene synthesis and sequencing of human genomes and of the genomes of microbes and animals for costs that are approaching $1000 for 3 billion bases.
4. New techniques such as RNA activation and refinement of RNA interference and gene therapy. The creation of multiple options for gene therapy to use different viral and new synthetic containers to deliver the genetic material. The better sensors can then track the delivery of drugs and genetic material within the body.

Combined it can mean in over the next 30 years we will have stunning progress in conquering disease and improving human performance.

There are 10 to 100 trillion cells in the human body Around 2025, several thousand personal thousand petaflop computers combined with supersensors could track and moderate the activity of all cells, genes, proteins, viruses, chemicals and bacteria in and around each person.

If we are clever about it we can get most of the benefits far sooner than waiting for a brute force approach of massive calculation and sensors. A lot of the activity is not important. We can get by with a lot less by identifying or controlling the important activity.

The areas which I think are most promising are the supercharge our immune system and regenerative processes.

Faster and more sensitive viewing of cell activity

Optical interferometry has been used to see better for astronomy to spot planets around stars. It has now been applied to seeing the activity and structure of living cells at the nanometer scale A research group in the MIT Spectroscopy Lab, led by postdoctoral associate Christopher Fang-Yen, is using optical interferometry to watch the activity of individual neurons. With this technique, Fang-Yen was able to detect small twitches of a few nanometers in nerve fibers and single neurons during an action potential, or electrical impulse.
The optical technique developed by the Spectroscopy Lab creates nanometer-scale images in less than a millisecond, and it's not subject to photobleaching or phototoxicity.

Researchers at MIT's George R. Harrison Spectroscopy Lab have been studying the changes in cells that are effected by disease like malaria. Michael Feld, director of the lab, hopes to use the technique to create three-dimensional images, illuminating even finer activities within living cells. The goal, says Feld, is to "study the structure of a living cell and the way it changes as circumstances change."

John Sedat, professor of biochemistry at the University of California, in San Francisco, sees this optical imaging technique as a new perspective in an evolving field. "There's a kind of miniature revolution taking place in microscopy," he says. "This is an example of physics people coming into biology and bringing in a lot of new ways of seeing things."

November 16, 2006

RNA activation

From new scientist magazine, RNA activation is a new technique that boosts gene activity, providing a genetic "on" switch. RNAi can silence genes in two ways. It can block the messenger RNA that is the intermediate between gene and protein and it can also interfere with "promoter" sequences that boost a gene's activity. It was while investigating this second phenomenon that Long-Cheng Li of the University of California, San Francisco, and his colleagues stumbled on the new method, dubbed RNA activation.

Although the exact mechanism remains unclear, Li's team has already found that it requires a protein called Ago2, which is also involved in the standard RNAi process. Li believes RNA activation could find widespread use, for example in treating cancer by boosting the activity of tumour suppressor genes.

It could also a workaround to achieve the objectives of gene therapy.

Rapid Virus detection part of transformation from cheap, rapid sensors

Improvements using rows of silver nanorods enhances the signal from a technique, called surface enhanced Raman spectroscopy (SERS) so that individual viruses can be rapidly identified SERS works by measuring the change in frequency of a near-infrared laser as it scatters off viral DNA or RNA. This change in frequency, named the Raman shift for the scientist who discovered it in 1928, is as distinct as a fingerprint.

Previously the ability of superconductors to detect and differentiate the frequency of photons with 50-100 times greater precision was noted to be able to detect different radioactive isotopes.

Being able to precisely detect, locate and analyse pathogens, poisons and materials will transform public health and civil defence against disease and bioweapons. Remotely being able to detect nuclear weapons and nuclear materials can also shift the geopolitical landscape. Sufficiently advanced sensors could make it nearly impossible to hide chemical, biological and nuclear WMDs.

New Scientist has forecasts for the next 50 years

In New Scientist magazine, they have forecasts for the next 50 years.

Several of the forecasts involve discovering alien life or the remains of alien life and several forecast breakthroughs in understanding the workings of the brain and mind

Here are the ones I agree with or find interesting. The forecasts I agree with tend to be too conservative. Although the Nathan Myhrvold and Bill Joy predictions are just a statement of a general direction and identifying an area of high impact.

Nathan Myhrvold predicts: Applied physics will be revolutionised in the next 50 years in ways we never thought possible, by advances in metamaterials, substances whose intricate synthetic structures enable them to transcend many of the limitations of natural materials. Better telescopes, microscopes and invisibility are just the earliest breakthroughs from metamaterials. Metamaterials will completely change the way we approach optics and nearly every aspect of electronics. Just as solid-state devices replaced vacuum tubes, metamaterial optics will make glass lenses a quaint artefact of an obsolete era. Other metamaterials designed to shepherd electrons more precisely and efficiently could solve the heat and scaling problems that plague microcircuitry.

David Deutch predicts quantum computers On the theoretical side, I expect a further major integration between physics and information science. The key breakthrough would be the development of a quantum theory of construction - the general theory of what, according to the laws of physics, can or cannot be built and with what resources.

Bill Joy forecasts clean, inexhaustible and cheap energy sources.

Francis Collins predicts advances in genetics and anti-aging will dramatically lengthen lifespans Richard Miller predicts the key breakthrough will be the elucidation of the molecular pathways that render cells from long-lived animals - whales, people, bats, porcupines - resistant to many forms of injury. Bruce Lahn predicts the creation of unlimited organs for transplantation

Peter Atkins forecasts the creation of synthetic life

Eric Horvitz predicts computers and artificial intelligence systems that will drive technological breakthroughs and advancement of technology. (A conservative way of stating that we will have reached some form of technological singularity without the associated implications). Rodney Brooks forecasts some progress with Artificial Intelligence

I believe the worst prediction is
Taking some form of psychodelic drugs so that we can accept our mortality This is bad to not fix our problems but to take drugs so you do not care that you have not fixed it.

Some of the predictions are for things that are already well underway
Susan Greenfield forecasts brain imaging will be able to see changes at the synaptic level that underpin learning. This has already started to be done with animals Miniturization and other advancement will allow this to be done less invasively.

Diamond coated silicon nanowires carry 100 times the current

nanowires coated with diamond can be up to 100 times better at carrying electric current than bare nanowires at very low temperatures, and two times better at room temperature. This improvement is determined by a property known as electron mobility.

The diamond-coating technique suggested by Balandin and Fonoberov enhances electron mobility in a very different way: "phonon engineering." Phonons are basic units, or "quanta," of mechanical vibration; sound waves are examples of acoustic phonons. Phonons play a bothersome role in semiconductor devices by scattering electrons. These problems are compounded when the features of electronic devices are reduced to the nanometer scale.

When a silicon nanowire is surrounded by diamond, the electron-phonon scattering inside the nanowire is suppressed and, as a result, the electron mobility is increased. This is an absolutely new method of mobility enhancement. An added bonus of diamond is that it is an excellent conductor of heat, which could allow it to impart valuable thermal management properties to circuits.

November 15, 2006

DARPA funding micro cameras

DARPA is fuding a short wave infrared video that are heavy as two quarters -- about 10 grams -- and able to pick out child-sized targets from 100 meters away. They would be mounted on helmets or small drones and use less than 200 milliwatts of power. The agency wants an entire featherweight imaging system -- including batteries, a goggle-mounted 1280 x 1024 display, and all the signal processing -- in a 350-gram package.

Small cameras exist now but they do not have the resolution that DARPA is requiring

November 14, 2006

30 nanometer diameter DNA Barrels

A group of students at Harvard University have constructed 30 nanometers in diameter DNA containers. The DNA barrels could one day be used to deliver drugs or gene or protein-based therapies to specific tissues in the body.

While DNA architecture previously took years to design and construct, a method developed earlier this year provides a relatively easy way to program DNA into specific shapes. A single long strand of DNA is studded with shorter snippets of specially designed DNA sequences that act as the chemical equivalent of staples. Each snippet will only bind to a specific spot on the DNA molecule. Strategically placing these staples along the DNA strand allows the molecule to self-assemble into different shapes.

By adapting this method to build three-dimensional structures, the students and their advisor William Shih, a Harvard scientist who has been a leader in DNA architecture, designed a DNA sequence that would fold into a tiny, hollow container. The final structure, which is shaped like an open barrel, consists of a single DNA molecule that zigzags back and forth to create a pleated sheet. The sheet is programmed to curve around on itself, creating a double-walled cylinder.

Some DNA-based structures have an inherent floppiness that makes three-dimensional shapes collapse. But the building method used to create the barrel--lining up a series of DNA helices into a pleated-sheet structure--seems to provide new strength.

Probably more disease and death from warmer climate

A warmer world already seems to be producing a sicker world, health experts reported Tuesday, citing surges in Kenya, China and Europe of such diseases as malaria, heart ailments and dengue fever. A study of three Chinese cities found annual excess deaths totaled between 173 and 685 per million residents, Jin said. Projected over the huge Chinese population of 1.3 billion, this could amount to as many as 890,000 deaths nationwide per year.

The populations developing nations of Africa and Asia would be more vulnerable to disease and adverse weather conditions. Developed nations are not immune such as the nearly 15,000 heat wave deaths suffered in France in 2003. Across europe the heat wave killed at least 35,000 and as many as 50,000

These and other effects of global warming and pollution indicate the urgent need to take action to reduce the use of coal. As I have noted a strong push for nuclear power is part of the solution to achieve the fastest results.

AMD and Intel talk about teraflop PCs in 2008/2010

AMD is making Fusion chips from x86 CPUs with on-board graphics accelerators (GPUs). Current GPUs have up to 360 Gflops of processing power. The Fusion chips aim to increase performance-per-Watt for applications such as 3D graphics, digital media and technical computing. There are two significant design challenges in developing such architectures — power management and memory hierarchy.

By 2010 AMD hopes to release a Teraflop CPU/GPU processor. He showed an example of how this would be achieved: 48 GPU pipes x 8 Flops/cycle x 3GHz = 1 Teraflop (peak performance) per socket. AMD also announced that it will release a processor combining the CPU and GPU (graphics processing unit) on one die in late 2008 or early 2009. AMDs CTO Hester said that the new CPU/GPU processors would offer a good Microsoft Vista experience as a minimum. Hopefully we can come up with better uses for teraflop computers than running a bloated operating system.

Intel is aims to offer 80 3.1GHz cores on one die by 2010 in order to achieve teraflop computing

Note: that the first teraflop supercomputer ASCI Red started broke the teraflop barrier Dec 1996. So it may take 12-14 years for that to migrate to personal computers.

Petaflop computers can be considered to have arrived with Japan's MDGrape3 computer (June 2006), an IBM machine in 2007 or with a Cray machine expected in 2008

A personal petaflop computer would be expected in 2018-2021 given the same gap as the teraflop. I have predicted that it will happen sooner in 2016-2018.

GPUs have been improving at 2 to 2.5 times every year which is faster than the 1.5 times improvement of Moore's law The 2.5 per year rate against the current 350 Gflops/second GPU performance would mean petaflop performance by 2015.

November 13, 2006

Seeing with superconductors

The November issue of Scientific American, has an article "Seeing with Superconductors Scientific and industrial photon detectors peer into the electromagnetic realms beyond that of visible light--into the low-frequency (long-wavelength, low-energy) world of infrared and microwaves and into the high-frequency regime of x-rays and gamma rays. Superconductors can see visible and longer wavelengths and detect an individual photon and discern its frequency, and thus its energy, with accuracy. The superconductors have sensitivities that are 50 times greater than the best recent systems. This means that new nuclear detectors can tell the difference between the radium 226 in cat litter and uranium 238 in dirty bombs and nuclear weapons.

The new superconductor devices will also revolutionize the analysis of microchips, submillimeter band astronomy, the study of the cosmic microwave background, quantum cryptography and the search for dark matter. Superconducting detectors that can measure photon numbers efficiently at telecommunication wavelengths with a negligible error rate, opening the way to secure quantum cryptography over a distance of 100 kilometers.

Here is a pdf that describes the 10,000 pixel submillimeter SCUBA-2 , which perform surveys of the sky 1000 times faster than SCUBA-1. All areas of astronomy will benefit, from studies of our Solar System and surveys of protostellar complexes in the Milky Way, to answering key questions about the formation and evolution of galaxies in the early Universe.

SCUBA 2 represents a major innovation from current submillimetre instruments. Incorporating state-of-the-art technology will allow the realisation of the first large-format "CCD-like" camera for submillimetre astronomy.

More nanotube progress

Hongjie Dai and his colleagues take a new approach for getting 100% semiconducting nanotubes. They grow a mixed bunch of semiconducting and metallic nanotubes on a silicon wafer and have them bridge the source and drain of a transistor. Then they expose the devices to methane plasma at 400 °C. The hot, ionized methane particles eat away the carbon atoms, but only in the metallic nanotubes, converting the tubes into a hydrocarbon gas. (The plasma also etches out nanotubes with diameters smaller than about 1.4 nanometers.) Next, the researchers treat the wafer in a vacuum at a temperature of 600 °C; this treatment gets rid of carbon-hydrogen groups that latch on to the semiconducting nanotubes during the plasma treatment. This leaves behind purely semiconducting nanotubes with a consistent range of diameters stretching across the source and drain. With this heat based approach, one can treat an entire wafer, which may contain several devices, at once.

From space, NASA's Goddard Space Flight Center in Greenbelt, Maryland licensed its patented technique for manufacturing high-quality single-walled carbon nanotubes (CNTs) to Idaho Space Materials (ISM) in Boise. Having successfully commercialized NASA's manufacturing process to increase production capacity while maintaining quality, ISM can produce single-walled CNTs at a rate of 50 grams per hour. The key to the innovation developed by Dr. Benavides was the ability to produce bundles of CNTs without using a metal catalyst, dramatically reducing pre- and post-production costs while generating higher yields of better quality product.

Correct the scale of treatment for the coal disease

Firstly, coal power never left. New coal power went from almost 95% to 50% but it never went away.

The December, 2006 issue of Discover magazine has an article about the dangers of a return to coal power and the Independent talks about what we can use to replace oil the way oil replaced coal.

People talk about future power but the technologies of the past like coal still have a firm grip on our world and our economy.

The Discover magazine article has a couple of things that I will note:
1. 7% of the Appalachian forest has been obliterated by mountain top-removal mining.
Images of coal mountain top removal are all over the internet, here is one example.
9-15 men using explosives and massive bulldozers remove a mountain top in about 14 months then scoop out the coal. The alternative is mine shafts but that has deaths rate that are 10-100 times higher.

2. 2.5 billion tons of carbon are put into the atmosphere every year from coal. Included with that are 20,000 tons of radioactive uranium and thorium and thousands of tons of mercury and arsenic. The best of newest coal plants (Futuregen) on the drawing board only capture 90% of the carbon and would not clean up the other pollutants. It costs $100/ton to sequester the carbon. So if we keep the existing coal plants it will take $250 billion/year to store the carbon. The carbon scrubbers do not get react to get the other material. So we would still get the radioactive material and other poisons. It will take decades to convert over to carbon sequestering and cleaner coal plants. We are looking at 9 new IGCC (integrated gasification combined cycle plants) which wold help reduce emissions over the next decade starting in about 2013. That much carbon is not good for the environment. Even without talking about global warming the most anti-environmental must recognize the actual deaths from coal mining, significant pollution deaths, and environmental damage. The greatest global warming doubters must accept that global warming as a risk is increased by the 2.5 billion tons of carbon and global warming would be a bad thing.

As has been noted Coal causes 178000 premature deaths in major Chinese cities every year. Adding in rural Chinese areas would increase this to 400,000. 27,000 premature deaths in the United States as noted by the American lunch association.

Coal provides about 2 terawatts of global electricity every year and we are adding about 100 gigawatts every year in new coal plants. Coal power is a mid to late stage cancer that is killing the world, animals, plants and hundreds of thousands of people every year. Even the doubters cannot say that the mountain forests (plants) have not been removed. The doubters cannot say that ten thousand do not die each year digging up the coal around the world.

We need an aggressive nuclear energy program to help accelerate the removal of coal power. Just using solar (1.7GW added in 2005), wind (12 GW added in 2005) and hydro is like saying let us take some drugs to slow the growth of cancer tumors by 5% each year. But let us not take the nuclear capsules which can also slow the growth because we are scared the capsules could break. A three mile island nuclear "capsule" breaking caused no deaths and the Chernobyl "capsule" was the worst but it only caused 1/10,000th of the deaths in that year compared to coal. 100 capsules each year would stop the coal tumor growth and an additional 2000 capsules replaces the existing coal power cancer. We need the whole treatment cocktail. (conservation, biofuels, solar, wind, and nuclear.) Using everything gets to a cure within 20-40 years. Leaving big parts of the solution out means it takes decades longer to stop the coal tumor growth and decades more to get rid of our current tumors. Meanwhile the coal tumors kill over 1,000 every day and are already making planet sick and could kill the planet at some point. We just don't know when.

Happy thoughts and partial treatments will leave you dead.

November 12, 2006

Comprehensive model is first to map protein folding at atomic level

Scientists at Harvard University have developed a computer model that can fully map and predict protein folding for some 10 microseconds -- about as long as some proteins take to assume their biologically stable configuration, and at least a thousand times longer than previous methods.

The work could help researchers better understand the abnormal protein aggregation underlying some devastating diseases, as well as how natural proteins evolved and how proteins recognize correct biochemical partners within living cells.

The model developed by Shakhnovich and colleagues faithfully describes and catalogs countless interactions between the individual atoms that comprise proteins. In so doing, it essentially predicts, given a string of amino acids, how the resulting protein will fold -- the first computer model to fully replicate folding of a protein as happens in nature. In more than 4,000 simulations conducted by the researchers, the computer model consistently predicted folded structures nearly identical to those that have been observed experimentally.

This is a big development that could accelerate our control at the molecular level.

Other reading:
Protein folding calculations using variational analysis to make the calculation of protein folding a billion times simpler.

Costs in synthetic genetics

Making biology more like computers and engineering

Synthetic biology

DNA and RNA nanotechnology survey

Protein Based Assembly of Nanoscale Parts

Audio telescope can differentiate birds and probably human conversations

Researchers at the National Institute of Standards and Technology (NIST), Intelligent Automation, Inc. (Rockville, Md.) and the University of Missouri-Columbia have modified a NIST-designed microphone array to make an "audio telescope" that could help airports more efficiently avoid costly and hazardous bird-aircraft collisions by locating and identifying birds by their calls.

Worldwide, wildlife strikes --mostly birds--have destroyed more than 163 aircraft and killed more than 194 people since 1988. Airports fight back with X-band radar and infrared cameras to monitor birds, but neither technology can distinguish between different kinds of birds, particularly in bad weather. That's important because not all birds are equally hazardous to aircraft, and shutting down runways because of the proximity of unknown birds imposes its own costs in delays and increased aircraft congestion.

The "audio telescope" proposed by NIST and IAI researchers is a one-meter-diameter concentric array of 192 microphones that would be mounted parallel to the ground to listen to the skies. By comparing the arrival time of sounds at different microphones, the array can determine the direction from which the sound came, even distinguishing simultaneous sounds coming from different directions. The researchers adapted mathematical algorithms designed to allow speech recognition systems to identify different speakers in order to distinguish different species by their calls. The system can tell a Canada goose from a gull or a hawk within a couple of seconds.

The acoustic bird monitor is an extension of the NIST Mark-III Microphone array, a high-performance, directional, audio signal processing system developed as a test platform for speech-recognition computing systems in complex sound environments, such as meeting rooms.

Speculation: It seems that the NIST Mark-III or later versions would be able to spy on selected conversations in a marketplace, restaurant or auditorium.

Other reading:
Gigapixel cameras and other visual surveillance

Super lidar in the works

Mundane spy gear

Bridging neurons and electronics with carbon nanotubes

New implantable biomedical devices that can act as artificial nerve cells, control severe pain, or allow otherwise paralyzed muscles to be moved might one day be possible thanks to developments in materials science. Nicholas Kotov of the University of Michigan, USA, and colleagues describe how they have used hollow, submicroscopic strands of carbon, carbon nanotubes, to connect an integrated circuit to nerve cells. The new technology offers the possibility of building an interface between biology and electronics.

The researchers built up layers of their SWNTs to produce a film that is electrically conducting even at a thickness of just a few nanometers. They next grew neuron precursor cells on this film. These precursor cells successfully differentiated into highly branched neurons. A voltage could then be applied, lateral to the SWNT film layer, and a so-called whole cell patch clamp used to measure any electrical effect on the nerve cells. When a lateral voltage is applied, a relatively large current is carried along the surface but only a very small current, in the region of billionths of an amp, is passed across the film to the nerve cells. The net effect is a kind of reverse amplification of the applied voltage that stimulates the nerve cells without damaging them.

Kotov and his colleagues report that such devices might find use in pain management, for instance, where nerve cells involved in the pain response might be controlled by reducing the activity of those cells. An analogous device might be used conversely to stimulate failed motor neurons, nerve cells that control muscle contraction. The researchers also suggest that stimulation could be applied to heart muscle cells to stimulate the heart.

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