Stanford professor oversees development of asteroid early-detection system

By Max McClure

Courtesy of B612 Foundation Illustration showing the Sentinel Space Telescope in space.

The Sentinel Space Telescope’s orbit will allow it to continuously monitor the asteroids that cross Earth’s orbit while facing away from the sun. (Click image to enlarge)

A large asteroid colliding with Earth may seem like a science fiction scenario, but there’s reason to take it seriously. Hundreds of thousands of these bodies cross Earth’s orbit – and the consequences of a direct hit by even one could be devastating.

But a new telescope, whose development is being overseen by Stanford Professor Scott Hubbard, promises to provide an early-detection system that could predict a devastating impact.

“We should be able to establish orbits well enough that we can predict where the asteroids will be in 50 to 100 years,” said Hubbard, an aeronautics and astronautics professor.

The mission to launch the telescope was announced Thursday in San Francisco at the California Academy of Sciences by the nonprofit foundation funding it. It was hailed as the first privately funded deep space mission.

With NASA support, the B612 Foundation will send the infrared telescope, called Sentinel, into orbit around the sun, where it will map the swarms of large asteroids that populate the inner solar system. The telescope is expected to be ready for launch on the SpaceX Falcon 9 rocket in five to six years.

“The B612 Sentinel mission extends the emerging commercial spaceflight industry into deep space – a first that will pave the way for many other ventures,” said Hubbard, program architect for the mission.

Private space

In recent years, the private spaceflight movement has racked up a number of high-profile milestones, including the first private suborbital spaceflight in 2004 and the first private payload delivery to the International Space Station this year.

L.A. CiceroFormer astronaut Rusty Schweickart, B612 Foundation CEO Ed Lu and Stanford Professor Scott Hubbard

Former astronaut Rusty Schweickart, B612 Foundation CEO Ed Lu and Stanford Professor Scott Hubbard answer questions about the telescope at a press conference on Thursday.

Stanford has been involved in the field since 2010, as a member of the Federal Aviation Administration’s Center of Excellence for Commercial Space Transportation.

“Fifty years ago, space was the exclusive province of governments,” said Hubbard. “Now we’re reaching a tipping point.”

But the announcement from the B612 Foundation – named for the asteroid home of French writer Antoine Saint-Exupéry’s Little Prince – goes beyond the low-orbit ambitions of other private-sector space missions.

Led by CEO Ed Lu, a Stanford alumnus, and Mission Director Harold Reitsema, the group aims instead to place its space telescope deep into space, near Venus’s orbit.

The device will range from 30 million to 170 million miles from Earth – hundreds of thousands of times farther than the Hubble Space Telescope, and in prime position to detect large objects before they come close to Earth. Ball Aerospace has submitted a proposal for Sentinel’s construction.

Exploring the neighborhood

Near-Earth asteroids are potential scientific gold mines, likely holding clues to conditions in the early solar system.

They may also pose a significant threat to life on this planet.

A recent National Research Council report concluded that although collisions with asteroids are rare, “one must also consider the extreme damage that could be inflicted by a single impact.”

An example often cited is the impact that devastated more than 2,000 square kilometers of Siberian forest in 1908. Scientists say it was likely due to an object a few dozen meters across.

More than half a million asteroids of that size or larger coexist with us in the inner solar system. Although NASA’s Spaceguard project has mapped the largest of these, hundreds of thousands of objects remain unmonitored.

During its projected five-and-a-half years of operation, Sentinel is meant to remedy that gap. The infrared telescope will scan the entire sky every 26 days with a 24 million-pixel array, sending information about asteroid locations and trajectories back to Earth via NASA’s Deep Space Network of antennas.

The telescope’s observations could be used to identify threats decades in advance of an impending collision.

Scientists said that with enough advance warning, a well-placed projectile, nuclear explosion, or “gravity tractor” – a massive spacecraft that would pull asteroids with its own gravitational field – could redirect a potentially devastating impact.

Data explosion

The data the mission is expected to produce will also be made freely available to the scientific and educational communities.

“I think there’s going to be a huge opportunity for student engagement,” said Hubbard.

The California Academy of Sciences and the Planetary Society, headed by Bill Nye, intend to partner with the foundation, and Hubbard hopes to involve students in analyzing Sentinel’s mapping data.

Asteroid locations and trajectories will, however, primarily serve as the basis of the near-Earth object protection system suggested by the National Research Council’s report on asteroid hazards.

“For millions of years, we have been a cosmic target, with occasionally devastating consequences,” said B612 Foundation co-founder Rusty Schweickart. “To say that we, as human beings, are going to put a stop to that is a very powerful statement.”

Media Contact

Scott Hubbard, Aeronautics and Astronautics: (650) 498-7077, scott.hubbard@stanford.edu

Max McClure, Stanford News Service: (650) 725-6737, maxmc@stanford.edu

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New Candidate Drug Stops Cancer Cells, Regenerates Nerve Cells, Cincinnati Children’s Hospital Medical Center

New Candidate Drug Stops Cancer Cells, Regenerates Nerve Cells

Thursday, June 21, 2012

Scientists have developed a small-molecule-inhibiting drug that in early laboratory cell tests stopped breast cancer cells from spreading and also promoted the growth of early nerve cells called neurites.

Researchers from Cincinnati Children’s Hospital Medical Center report their findings online June 21 in Chemistry & Biology. The scientists named their lead drug candidate “Rhosin” and hope future testing shows it to be promising for the treatment of various cancers or nervous system damage.

The inhibitor overcomes a number of previous scientific challenges by precisely targeting a single component of a cell signaling protein complex called Rho GTPases. This complex regulates cell movement and growth throughout the body. Miscues in Rho GTPase processes are also widely implicated in human diseases, including various cancers and neurologic disorders. 

“Although still years from clinical development, in principle Rhosin could be useful in therapy for many kinds of cancer or possibly neuron and spinal cord regeneration,” said Yi Zheng, PhD, lead investigator and director of Experimental Hematology and Cancer Biology at Cincinnati Children’s. “We’ve performed in silica (computerized) rational drug design, pharmacological characterization and cell tests in the laboratory, and we are now starting to work with mouse models.”
 
Because the role of Rho GTPases in cellular processes and cancer formation is well established, researchers have spent years trying to identify safe and effective therapeutic targets for specific parts of the protein complex. In particular, scientists have focused on the center protein in the complex called RhoA, which is essential for the signaling function of the complex. In breast cancer for example, increased RhoA activity makes the cancer cells more invasive and causes them to spread, while a deficiency of RhoA suppresses cancer growth and progression.

Despite this knowledge, past efforts to develop an effective small-molecule inhibitor for RhoA have failed, explained Zheng, who has studied Rho GTPases for over two decades. Most roadblocks stem from a lack of specificity in how researchers have been able to target RhoA, a resulting lack of efficiency in affecting molecular processes, problems with toxicity, and the inability to find a workable drug design.

For the current study, Zheng and his colleagues started with the extensive body of research from Cincinnati Children’s and other institutions describing the processes and functions of Rho GTPases. They then used high-throughput computerized molecular screening and computerized drug design to reveal a druggable target site. This also provided a preliminary virtual simulation on the potential effectiveness of candidate drugs.

A key challenge to binding a small-molecule inhibitor to RhoA is the protein’s globular structure and lack of surface pocket areas suitable for easy binding, Zheng said. The unique chemical structure of the lead compound identified by researchers, Rhosin, allows it to effectively bind to two shallow surface grooves on RhoA. This enables the candidate drug to take root and begin affecting cells. The two-legged configuration of Rosin also describes a useful drug design strategy for more effectively targeting difficult molecular sites like RhoA.

The researchers also wanted to make sure Rhosin effectively blocked what are known as guanine nucleotide exchange factors (GEFs). Guanine nucleotide is a critical energy source and signaling component of cells. Activation of GEFs is required to set off the regulatory signaling of GTPases (GTP stands for guanosine triphosphate).

After conducting a series of laboratory cell tests to verify the targeting and binding capabilities of Rhosin to RhoA, the researchers then tested the candidate drug’s impact on cultured breast cancer cells and nerve cells.

In tests on a human breast cancer cells, Rhosin inhibited cell growth and the formation of mammary spheres in a dose dependent manner, acting specifically on RhoA molecular targets without disrupting other critical cellular processes. Rhosin does not affect non-cancerous breast cells. This, along with other tests the scientists performed, indicated Rhosin’s effectiveness in targeting RhoA-mediated breast cancer proliferation, according to the researchers.

Researchers also treated an extensively tested line of neuronal cells with Rhosin, along with nerve growth factor, a protein that is important to the growth and survival of neurons. Rhosin worked with nerve growth factor in a dose-dependent way to promote the proliferation of branching neurites from the neuronal cells. Neurites are young or early stage extensions from neurons required for neuronal communications.

Write speeds for phase-change memory reach record limits | Ars Technica

DRAM in computers is erased when a computer is turned off.

By pre-organizing atoms in a bit of phase-change memory, information can be written in less than one nanosecond, the fastest for such memory. With write speeds comparable to the memory that powers our computers, phase change memory could one day help computers boot up instantly.

Phase-change memory stores information based on the organization of atoms in a material, often a mixture of germanium, antimony, and tellurium (Ge2Sb2Te5 or GST). A voltage pulse heats the metal and disordered atoms in the crystal rearrange into an ordered crystal. Restoring the disordered arrangement by melting the glassy material erases the information. A computer reads each bit by detecting the lower electrical resistance of the ordered crystal.

Micron sells small phase-change memory (PRAM) chips. Companies like IBM and Samsung are working on PRAM chips too.

Phase-change memory could one day replace flash memory in our cellphones, just as Samsung briefly tried in a commercial smartphone. PRAM can top the density and write times of flash memory. And like flash, PRAM is nonvolatile, meaning that it retains its information even when a device is powered off.

That makes phase-change memory an intriguing candidate to replace the volatile DRAM that powers our computers. But a computer that boots up instantly using PRAM is still a long way off, partly because the materials can’t be switched from disordered to ordered, or written quickly enough. Most phase-change materials crystallize slower than the 1-10 nanoseconds it takes to write a bit of DRAM. And materials that crystallize faster at PRAM operating temperatures tend to naturally organize at lower temperatures too, says Stephen Elliott of the University of Cambridge. Therefore, they slowly crystallize and erase themselves over time.

Elliott and his colleagues have boosted the crystallization time, and thus the write speed, of a stable PRAM bit. They pre-organized the atoms in a chunk of Ge2Sb2Te5 using a weak electric field. The scientists sandwiched a 50nm-wide cylinder of GST between two titanium electrodes and applied 0.3V of potential across the material. A 500-picosecond burst of 1V electrical potential triggered the crystallization, which is about 10 times faster than the best speed using a germanium-tellurium material.

The scientists melted the GST crystal, thus erasing the memory, with a similar 6.5V pulse. The material’s resistance was stable for 10,000 write-rewrite cycles.

Computer models of the material show that the constant low voltage causes tiny seed crystals to form, basically “priming” the atoms for complete crystallization.

Most researchers have tried to improve the switching speed of phase change memory by randomly inserting metals into GST, says Robert Simpson, at the Institute of Photonic Sciences in Spain. Learning how to create crystal seeds through simulations and then demonstrating how these seeds speed crystallization in a device is a more scientific approach to developing new memory materials, he adds.

Eric Pop, of the University of Illinois, Urbana-Champaign, is excited to see the speed limits of phase-change memory bits, but wonders if the extra power needed to maintain the low priming voltage would influence the speed and energy consumption of a chip containing many phase-change bits. Ultimately, consumer cost influences the commercial viability of PRAM chips, he adds.

This story was updated on June 25, 2012 to reflect the fact that GST is a glassy material, not a metal. References to voltage as energy and power were replaced by electrical potential.

Science, 2012. DOI: 10.1126/science.1221561 (About DOIs).

A look inside Leap Motion, the 3D gesture control that’s like Kinect on steroids | KurzweilAI

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The Leap (credit: Leap Motion)

Leap Motion‘s motion-tracking system is more powerful, more accurate, smaller, cheaper, and just more impressive than Kinect.

The Leap uses a number of camera sensors to map out a workspace of sorts — it’s a 3D space in which you operate as you normally would, with almost none of the Kinect’s angle and distance restrictions.

Currently the Leap uses VGA camera sensors, and the workspace is about three cubic feet; Holz told us that bigger, better sensors are the only thing required to make that number more like thirty feet, or three hundred. Leap’s device tracks all movement inside its force field, and is remarkably accurate, down to 0.01mm. It tracks your fingers individually, and knows the difference between your fingers and the pencil you’re holding between two of them.

Holz showed off a number of different use cases for Leap Motion’s technology. The simplest thing it can do is simulate a touch screen, so you can interact with any display as if it were touch-enabled.

Developers that do take advantage of the Leap’s SDK will be able to do much more, however, and the possibilities appear to be limited only by your imagination. All kinds of different apps are being developed: some could improving remote surgery, others allow easier navigation through complex models and data, and others might put you square in the middle of a first-person shooter.

Rather than mapping particular gestures (cross your arms to close the app, draw a circle to open a new window), Holz said developers are being encouraged to provide constant dynamic feedback. No one needed to be taught what pinch-to-zoom meant — it’s the natural thing to try and do on a touchscreen, and as soon as you start pinching or spreading it becomes clear what happens.

The Leap will cost $70 when it’s released — sometime between December and February — and Leap Motion is also working with OEMs to embed its technology into devices. The Leap is about the size of a USB drive, but Holz says it could easily be no larger than a dime, so adding it to a laptop or tablet shouldn’t be difficult.

The natural comparison to any motion control is Minority Report, an imagined future everyone seems to desperately want to come true. We asked Holz about the comparison, and if Leap Motion’s technology meant we’d all have Tom Cruise’s awesome PreCrime dashboard in the future.

“No,” he told us. “It’ll be even better.”

Learn That Tune In Your Sleep : Northwestern University Newscenter

EVANSTON, Ill. – Want to nail that tune that you’ve practiced and practiced? Maybe you should take a nap with the same melody playing during your sleep, new provocative Northwestern University research suggests.

The research grows out of exciting existing evidence that suggests that memories can be reactivated during sleep and storage of them can be strengthened in the process.

In the Northwestern study, research participants learned how to play two artificially generated musical tunes with well-timed key presses. Then while the participants took a 90-minute nap, the researchers presented one of the tunes that had been practiced, but not the other.

“Our results extend prior research by showing that external stimulation during sleep can influence a complex skill,” said Ken A. Paller, professor of psychology in the Weinberg College of Arts and Sciences at Northwestern and senior author of the study.

By using EEG methods to record the brain’s electrical activity, the researchers ensured that the soft musical “cues” were presented during slow-wave sleep, a stage of sleep previously linked to cementing memories. Participants made fewer errors when pressing the keys to produce the melody that had been presented while they slept, compared to the melody not presented.

“We also found that electrophysiological signals during sleep correlated with the extent to which memory improved,” said lead author James Antony of the Interdepartmental Neuroscience Program at Northwestern. “These signals may thus be measuring the brain events that produce memory improvement during sleep.”  

The age-old myth that you can learn a foreign language while you sleep is sure to come to mind, said Paul J. Reber, associate professor of psychology at Northwestern and a co-author of the study.

“The critical difference is that our research shows that memory is strengthened for something you’ve already learned,” Reber said. “Rather than learning something new in your sleep, we’re talking about enhancing an existing memory by re-activating information recently acquired.”

The researchers, he said, are now thinking about how their findings could apply to many other types of learning.

“If you were learning how to speak in a foreign language during the day, for example, and then tried to reactivate those memories during sleep, perhaps you might enhance your learning.”

Paller said he hopes the study will help them learn more about the basic brain mechanisms that transpire during sleep to help preserve memory storage.

“These same mechanisms may not only allow an abundance of memories to be maintained throughout a lifetime, but they may also allow memory storage to be enriched through the generation of novel connections among memories,” he said.

The study opens the door for future studies of sleep-based memory processing for many different types of motor skills, habits and behavioral dispositions, Paller said.

“Cued Memory Reactivation During Sleep Influences Skill Learning” will publish June 24 in the journal Nature Neuroscience. The research was supported by a grant from the National Science Foundation. In addition to Paller, Antony and Reber, co-authors include Eric W. Gobel of the Interdepartmental Neuroscience Program, and Justin K. O’Hare of the Department of Psychology, all of Northwestern University.

Revolutionizing Prosthetics

  • Revolutionizing Prosthetics

    When DARPA launched the Revolutionizing Prosthetics program in 2006, the state of upper-limb prosthetic technology was far behind lower-limb technology.  Advancing upper-limb technology was judged to be a more difficult medical and engineering challenge.

    When DARPA launched the Revolutionizing Prosthetics program in 2006, the state of upper-limb prosthetic technology was far behind lower-limb technology.  Advancing upper-limb technology was judged to be a more difficult medical and engineering challenge.

    After six years of development, the Revolutionizing Prosthetics program developed two anthropomorphic advanced modular prototype prosthetic arm systems, including sockets, which offer increased range of motion, dexterity and control options.

    Thirty-five volunteer amputees participated in a Department of Veterans Affairs (VA) funded optimization study in VA and DoD medical centers and provided design feedback for the development of the Gen-3 Arm System by DEKA Integrated Solutions Corporation, one of two primary performers on the Revolutionizing Prosthetics program.  Based on that testing and subsequent refinement, DEKA submitted a 510(k) premarket notification to the FDA in April 2012 seeking approval to make the Arm System commercially available.

    DARPA researchers have also attained promising initial results on achieving brain control of an advanced arm system developed by the Johns Hopkins University Applied Physics Lab, the second primary performer on Revolutionizing Prosthetics. This work with tetraplegic volunteers has demonstrated the potential to use advanced prostheses to improve the quality of life for victims of paralysis.

    The Revolutionizing Prosthetics program is ongoing and aims to continue increasing functionality of the DARPA arm systems so servicemembers with arm loss may one day have the option of choosing to return to duty. Additionally, the dexterous hand capabilities developed under the program have already been applied to small robotic systems used in manipulating unexploded ordnance, thus keeping soldiers out of situations that have led to limb loss.

YaleNews | Neurons that control overeating also drive appetite for cocaine

By Karen N. Peart

June 24, 2012

A lean animal and a control were both exposed to a novelty item (center). The lean animal spent more time exploring the novelty, as shown by the higher concentration of yellow in the slide.

Researchers at Yale School of Medicine have zeroed in on a set of neurons in the part of the brain that controls hunger, and found that these neurons are not only associated with overeating, but also linked to non-food associated behaviors, like novelty-seeking and drug addiction.

Published in the June 24 online issue of Nature Neuroscience, the study was led by Marcelo O. Dietrich, postdoctoral associate, and Tamas L. Horvath, the Jean and David W. Wallace Professor of Biomedical Research and chair of comparative medicine at Yale School of Medicine.

In attempts to develop treatments for metabolic disorders such as obesity and diabetes, researchers have paid increasing attention to the brain’s reward circuits located in the midbrain, with the notion that in these patients, food may become a type of “drug of abuse” similar to cocaine. Dietrich notes, however, that this study flips the common wisdom on its head.

“Using genetic approaches, we found that increased appetite for food can actually be associated with decreased interest in novelty as well as in cocaine, and on the other hand, less interest in food can predict increased interest in cocaine,” said Dietrich.

Horvath and his team studied two sets of transgenic mice. In one set, they knocked out a signaling molecule that controls hunger-promoting neurons in the hypothalamus. In the other set, they interfered with the same neurons by eliminating them selectively during development using diphtheria toxin. The mice were given various non-invasive tests that measured how they respond to novelty, and anxiety, and how they react to cocaine.

“We found that animals that have less interest in food are more interested in novelty-seeking behaviors and drugs like cocaine,” said Horvath. “This suggests that there may be individuals with increased drive of the reward circuitry, but who are still lean. This is a complex trait that arises from the activity of the basic feeding circuits during development, which then impacts the adult response to drugs and novelty in the environment.”

Horvath and his team argue that the hypothalamus, which controls vital functions such as body temperature, hunger, thirst fatigue and sleep, is key to the development of higher brain functions. “These hunger-promoting neurons are critically important during development to establish the set point of higher brain functions, and their impaired function may be the underlying cause for altered motivated and cognitive behaviors,” he said.

“There is this contemporary view that obesity is associated with the increased drive of the reward circuitry,” Horvath added. “But here, we provide a contrasting view: that the reward aspect can be very high, but subjects can still be very lean. At the same time, it indicates that a set of people who have no interest in food, might be more prone to drug addiction.”

Other authors on the study included Jeremy Bober, Jozelia G. Ferreira, Luis A. Tellez, Yann Mineur, Diogo o. Souza, Xiao-Bing Gao, Marina Picciotto, Ivan Araujo, and Zhong-Wu Liu.

The study was supported by The National Institutes of Health Director’s Pioneer Award to Horvath; and in part by the National Institute on Deafness and Other Communication Disorders.

Citation: Nature Neuroscience June 24, 2012, doi: 10.1038/nn.3147