September 22, 2010

Berkeley Lab Scientists Reveal Path to Protein Crystallization

(September 22, 2010)  By assembling a crystalline envelope around a cell, surface-layer (S-layer) proteins serve as the first point of contact between bacteria, extremophiles and other types of microbes  and their environment.  Now, scientists at the Molecular Foundry, a nanoscience user facility at Berkeley Lab, have used atomic force microscopy to image in real time how S-layer proteins form crystals in a cell-like environment. This direct observation of protein assembly could provide researchers with insight into how  microorganisms stave off antibiotics or lock carbon dioxide into minerals.

“Many proteins self-assemble into highly ordered structures that provide organisms with critical functions, such as cell adhesion to surfaces, transformation of CO2 into minerals, propagation of disease, and drug resistance,” said James DeYoreo, Deputy Director of the Molecular Foundry. “This work is the first to provide a direct molecular-level view of the assembly pathway in vitro. Once this knowledge can be extended to assembly in a living system, it may lead to strategies for capitalizing on or interfering with these functions.”

Unraveling the pathway for S-layer formation allows scientists to investigate how bacteria or other microbes negotiate interactions with their environment. DeYoreo and colleagues employed in situ atomic force microscopy—a probe technique used to study a crystal’s surface in its natural setting with atomic precision—to watch S-layer proteins assemble from solution onto a flat, biological membrane called a lipid bilayer. Unlike classical crystal growth, in which atoms form into ordered ‘seeds’ and grow in size, the team showed S-layer proteins form unstructured blobs on the bilayers before transforming into a crystalline structure over the course of minutes.

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Human-powered Ornithopter Becomes First Ever to Achieve Sustained Flight

(September 22, 2010)  Aviation history was made when the University of Toronto’s human-powered aircraft with flapping wings became the first of its kind to fly continuously.

The “Snowbird” performed its record-breaking flight on August 2 at the Great Lakes Gliding Club in Tottenham, Ont., witnessed by the vice-president (Canada) of the Fédération Aéronautique Internationale (FAI), the world-governing body for air sports and aeronautical world records. The official record claim was filed this month, and the FAI is expected to confirm the ornithopter’s world record at its meeting in October.

For centuries Engineers have attempted such a feat, ever since Leonardo da Vinci sketched the first human-powered ornithopter in 1485.

But under the power and piloting of Todd Reichert (EngSci OT5), an Engineering PhD candidate at the University of Toronto Institute for Aerospace Studies (UTIAS), the wing-flapping device sustained both altitude and airspeed for 19.3 seconds, and covered a distance of 145 metres at an average speed of 25.6 kilometres per hour.

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September 13, 2010

Wheelchair Makes the Most of Brain Control

Artificial intelligence improves a wheelchair system that could give paralyzed people greater mobility.

(September 13, 2010)  A robotic wheelchair combines brain control with artificial intelligence to make it easier for people to maneuver it using only their thoughts. The approach, known as “shared control,” could help paralyzed people gain new mobility by turning crude brain signals into more complicated commands.

The wheelchair, developed by researchers at the Federal Institute of Technology in Lausanne, features software that can take a simple command like “go left” and assess the immediate area to figure out how to follow the command without hitting anything. The software can also understand when the driver wants to navigate to a particular object, like a table.

Several technologies allow patients to control computers, prosthetics, and other devices using signals captured from nerves, muscles, or the brain. Electroencephalography (EEG) has emerged as a promising way for paralyzed patients to control computers or wheelchairs. A user needs to wear a skullcap and undergo training for a few hours a day over about five days. Patients control the chair simply by imagining they are moving a part of the body. Thinking of moving the left hand tells the chair to turn left, for example. Commands can also be triggered by specific mental tasks, such as arithmetic.

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September 12, 2010

Stanford researchers' new high-sensitivity electronic skin can feel a fly's footsteps

(September 12, 2010)  Stanford researchers have developed an ultrasensitive, highly flexible, electronic sensor that can feel a touch as light as an alighting fly.  Manufactured in large sheets, the sensors could be used in artificial electronic skin for prosthetic limbs, robots, touch-screen displays, automobile safety and a range of medical applications.

The light, tickling tread of a pesky fly landing on your face may strike most of us as one of the most aggravating of life's small annoyances.  But for scientists working to develop pressure sensors for artificial skin for use on prosthetic limbs or robots, skin sensitive enough to feel the tickle of fly feet would be a huge advance.  Now Stanford researchers have built such a sensor.

By sandwiching a precisely molded, highly elastic rubber layer between two parallel electrodes, the team created an electronic sensor that can detect the slightest touch.

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September 7, 2010


This photo shows two kinds of electrodes sitting atop a severely epileptic patient's brain
after part of his skull was removed temporarily.


(September 7, 2010)  In an early step toward letting severely paralyzed people speak with their thoughts, University of Utah researchers translated brain signals into words using two grids of 16 microelectrodes implanted beneath the skull but atop the brain.

"We have been able to decode spoken words using only signals from the brain with a device that has promise for long-term use in paralyzed patients who cannot now speak," says Bradley Greger, an assistant professor of bioengineering.

Because the method needs much more improvement and involves placing electrodes on the brain, he expects it will be a few years before clinical trials on paralyzed people who cannot speak due to so-called "locked-in syndrome."

The Journal of Neural Engineering's September issue is publishing Greger's study showing the feasibility of translating brain signals into computer-spoken words.

The University of Utah research team placed grids of tiny microelectrodes over speech centers in the brain of a volunteer with severe epileptic seizures. The man already had a craniotomy - temporary partial skull removal - so doctors could place larger, conventional electrodes to locate the source of his seizures and surgically stop them.

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