Science Scanner: World’s Smallest Electric Motor Made From Single Molecule

Posted September 7th, 2011 at 7:55 pm (UTC+0)
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Tufts University single molecule motor (Photo: Heather L. Tierney, Colin J. Murphy, April D. Jewell, Ashleigh E. Baber, Erin V. Iski, Harout Y. Khodaverdian, Allister F. McGuire, Nikolai Klebanov and E. Charles H. Sykes)

Tufts University single molecule motor (Photo: Heather L. Tierney, Colin J. Murphy, April D. Jewell, Ashleigh E. Baber, Erin V. Iski, Harout Y. Khodaverdian, Allister F. McGuire, Nikolai Klebanov and E. Charles H. Sykes)

Engineers have miniaturized a number of electronic and mechanical devices over the years, but chemists at Tufts University in Massachusetts have gone one step further;  they say they’ve developed the world’s first single-molecule electric motor.

The single-molecule device measures a mere one nanometer across. The current world record is a 200-nanometer motor. A single strand of human hair is about 60,000 nanometers wide.

The research team provided their molecular motor with electricity by using the metal tip of a state-of-the-art, low-temperature scanning tunneling microscope (LT-STM) to charge a butyl methyl sulfide molecule placed on a conductive copper surface.

The researchers say this sulfur-containing molecule had carbon and hydrogen atoms radiating off to form what looked like two arms, with four carbons atoms on one side and one on the other, allowing these carbon chains to freely rotate around the sulfur-copper bond.

The Tuft’s team believes its accomplishment is significant because these single-molecule devices could eventually lead to a new class of devices with medical and engineering applications.

E. Charles H. Sykes, Ph.D., associate professor of chemistry at Tufts and senior author on this project admits that, while he and his colleagues do see the potential for practical applications with this electric motor, it will need much more work and research to correct one of the device’s major drawbacks. Dr. Sykes expresses concern over the temperatures at which the electric-molecular motor operates, saying that right now, the motor spins much faster at higher temperatures, making it difficult to measure and control its rotation.

The study was recently published in the journal “Nature Nanotechnology.”

Next, the Tufts team plans to submit its electric motor to Guinness World Records.

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NASA Gets Clearest Images Yet of Apollo Landing Sites

Apollo 17 landing site as seen by NASA's Lunar Reconnaissance Orbiter (Photo: NASA/Goddard/ASU)

Apollo 17 landing site as seen by NASA's Lunar Reconnaissance Orbiter - to see bigger version click on picture (Photo: NASA/Goddard/ASU)

NASA has captured what it says are the sharpest images ever taken from space of the Apollo 12, 14 and 17 landing sites. Images show such detailed features as the twists and turns of the paths made when the astronauts explored the lunar surface.

The images were captured by the U.S. space agency’s Lunar Reconnaissance Orbiter (LRO).

According to NASA, tracks left by the lunar roving vehicle at the Apollo 17 landing site – the eleventh and final manned mission in the American Apollo space program – are clearly visible, along with the last foot trails left on the moon by astronauts Eugene Cernan and Harrison Schmitt.

The images of the various Apollo landing sites also show where the astronauts placed scientific instruments, such as the Lunar Surface Experiments Package (ALSEP), which provided the first insight into the moon’s environment and interior.

Also visible is the descent stage, which remained on the moon after the Lunar Excursion Module‘s (LEM) accent stage took the moon explorers back to their command module.

NASA says the high-resolution images were made possible because of adjustments made to the LRO’s orbit, which lowered the spacecraft from its usual altitude of approximately 50 kilometers to an altitude that dipped as low as nearly 21 kilometers as it passed over the moon’s surface.

The orbiter has since been returned to its normal 31-mile orbit.

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Modern Humans Interbred with Now Extinct Sub-species

Neanderthal (right) modern Homo Sapiens (left) comparison (Photo: Wapondaponda)

Neanderthal (right) modern Homo Sapiens (left) comparison (Photo: Wapondaponda)

Modern humans were interbreeding with now-extinct hominid beings even before migrating out of Africa, which is considered to be the cradle of all humanity, according to new findings from scientists at the University of Arizona.

It’s widely accepted that today’s humans (Homo sapiens) originated in Africa before migrating to all parts of the world.

DNA samples recovered from fossil remains of the now-extinct human relative, Neanderthal, have long shown there was interbreeding between modern humans and their more ancient predecessors after they left Africa for the cooler climates of Eurasia.

However, what was unclear until now, is whether there was an exchange of genetic material before that migratory trip from Africa.

With this research, Michael Hammer and his team from the University of Arizona in Tucson, have found evidence that the anatomically modern humans of today were not so unique that they remained separate from other more ancient hominid species or sub-species.

“We found evidence for hybridization between modern humans and archaic forms in Africa. It looks like our lineage has always exchanged genes with their more morphologically diverged neighbors,” said Hammer, an associate professor.

The team found the climate in more tropical areas, such as those in parts of Africa, makes it very tough for DNA to survive for extremely long periods of time. So, recovering usable samples from fossil specimens is extremely difficult, if not impossible.  As a result, no fossil DNA from Africa was available for testing.

To get around that potential dead end in the investigation, Dr. Hammer’s team developed a unique method to obtain data needed for its study.

Instead using DNA samples from fossilized remains, the team checked the DNA from modern humans belonging to African populations and searched for unusual regions in the genome. The researchers then used simulations to predict what ancient DNA sequences would look like had they survived within the DNA of our own cells.

The study was published in the Proceedings of the National Academy of Sciences.

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Narrowing the Gap Between Man and Machine

A semi-autonomous robot can be controlled with the brain waves of paralyzed patients. (Photo: José del R. Millán)

A semi-autonomous robot can be controlled with the brain waves of paralyzed patients. (Photo: José del R. Millán)

Researchers in Switzerland have invented a new, noninvasive method of recording patterns of brain activity that can then be used to  steer a robot.

The scientists hope  the technology will give patients who are too disabled to communicate the ability to interact with others.

We’ve previously written about similar brain-machine interface systems that make it possible for people to control robots and other electronic or mechanized devices with conscious thought, but that often takes lots of effort and concentration.

José del R. Millán, a biomedical engineer at the École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland, led the research and wants to make that control as easy as driving a car on a highway.

So Millan and his colleagues set out to develop a partially-autonomous robot, one that employs a shared control system which allows its user to stop concentrating on tasks that would normally be done subconsciously.  But should that robot encounter an unexpected event and a split-second decision would need to be made, the user’s thoughts – sent by a system that translates the person’s EEG signals into navigation instructions and is fed to the robot in real time – can override the device’s artificial intelligence.

Earlier research shows that EEG patterns for movement and navigation are similar from person to person. Millán’s group has previously demonstrated that, after a little practice, a healthy person can share control with the robot with very little effort.

But the research group wanted to learn how this system would work with patient who is bed-bound and perhaps hasn’t used his limbs for years.  Did that patient have the same pattern of brain waves and would the patient be able to control robots as just effectively as those who weren’t disabled?

The researchers recruited two patients with paralyzed lower bodies who’d been bed bound for six or seven years. The patients were trained to control the robot for one hour per week over a six-week period.  At the end of the training period, the researchers instructed the subjects to drive the robot to various targets around the lab for 12 minutes.

The researchers found that the disabled patients performed just as well as healthy subjects.

Dr. Millán now hopes to involve more bed-bound patients in the study and would like to see his unit modified to allow a user to control a prosthetic limb or wheel. He and his colleagues may eventually add an arm to their current robot to allow it to grasp objects as well.

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