Babies, Even When Premature, 'See' With Their Hands

Babies, Even When Premature, 'See' With Their Hands

  9:56:00 PM    Science Lover

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Even premature babies at 33 weeks post-conceptional age, about 2 months before term (40 gestational weeks), are capable of recognizing and distinguishing two objects of different shapes (a prism and a cylinder) with their right or left hands. This is the first demonstration of fully efficient manual perception in preterm human infants.

A premature baby holding a cylinder. (Credit: Copyright Frédérique Berne-Audéoud)

The phenomenon was discovered by researchers at two laboratories: the Laboratoire de psychologie et neurocognition (CNRS / University of Grenoble 2 / University of Chambéry) and the Laboratoire de psychologie de la perception (CNRS / University of Paris Descartes) in cooperation with a team from the Neonatology Department of the Grenoble University Hospitals. The findings have been published on the PLoS One website.

The source of all perceptual knowledge, the sense organs and sensory systems of premature babies are less efficient than those of full-term babies, even though the latter are also not yet fully developed. Starting in the very first minutes after birth, a full-term infant is subjected to extensive tactile stimulation: it is washed, held on its mother's stomach, nursed, diapered, etc. Its body almost immediately experiences contact with skin other than its own, with towels, sheets, nipples -- in short, with objects of different textures, shapes and consistencies. It is common knowledge that a baby will flex its fingers tightly if its palm is touched by a finger, but this grasping reaction is not just a simple reflex. Even in the first hours of its life, a full-term newborn already has effective manual perception, a tactile capacity that enables it to make sense of its environment. But what about the premature infant, whose neurological functions are even less developed due to its early birth?

To find out, the researchers conducted an experiment with 24 premature babies aged 33 to 34+6 gestational weeks (GW), approximately 2 weeks after their birth. Their average gestational age (age at birth) was 31 GW (which corresponds to about 7 months of pregnancy) and their average weight at birth was 1500 g. The research team adopted an experimental method based on habituation (first phase) and reaction to novelty (second phase), similar to that used for full-term newborns. This method relies on a simple universal principle: the gradual loss of interest that all humans experience in relation to a familiar object and the renewed attention elicited by a new, unfamiliar object. In the first phase, the researcher places a small object (a prism for half of the babies and a cylinder for the other half) in one of the baby's hands (the right hand for half of the group and the left for the other half). As soon as the infant lets go of the object, the experimenter places it back in the same hand and measures how long the baby holds the object each time. The researchers observed that the holding time decreased over the course of the trials, indicating that the baby had become "habituated" to the shape of the object.

In the second phase, once the babies are habituated to their first objects, the researchers present an object with a new shape to half of the group and a familiar object (the same as in the habituation phase) to the other half. The result: the holding time is longer for the new object (reaction to novelty) than for the familiar object. This proves that the decrease in holding time (observed in the first phase) is not due to the babies' simply growing tired, because otherwise they would not be more interested in something new.

This experiment reveals for the first time that preterm infants are capable of recognizing an object with their hands (tactile habituation) and that they show a preference for a novel object, reflecting their capacity to differentiate between two objects of different shapes (tactile discrimination). In other words, each time they hold an object, premature babies, like those born at term, are capable of extracting information tactilely on its shape, temporarily storing this information in their memory and comparing it with new tactile input. If the object is the same they soon stop holding it, but if it is different they show greater interest. Therefore, preterm infants, like full-term newborns, are receptive to tactile information and are already learning.

These findings improve our understanding of the perceptual capacities of premature babies and should help neonatology professionals optimize the handling and treatment of their preterm charges, in particular for the purpose of reducing their stress and offering them optimal conditions for their development.

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Quantum Breakthrough: New Materials Possible

Quantum Breakthrough: New Materials Possible

  11:13:00 AM    Science Lover

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Princeton engineers have made a breakthrough in an 80-year-old quandary in quantum physics, paving the way for the development of new materials that could make electronic devices smaller and cars more energy efficient.

Professor Emily Carter and graduate student Chen Huang developed a new way of predicting important properties of substances. The advance could speed the development of new materials and technologies. (Credit: Frank Wojciechowski)

By reworking a theory first proposed by physicists in the 1920s, the researchers discovered a new way to predict important characteristics of a new material before it's been created. The new formula allows computers to model the properties of a material up to 100,000 times faster than previously possible and vastly expands the range of properties scientists can study.

"The equation scientists were using before was inefficient and consumed huge amounts of computing power, so we were limited to modeling only a few hundred atoms of a perfect material," said Emily Carter, the engineering professor who led the project.

"But most materials aren't perfect," said Carter, the Arthur W. Marks '19 Professor of Mechanical and Aerospace Engineering and Applied and Computational Mathematics. "Important properties are actually determined by the flaws, but to understand those you need to look at thousands or tens of thousands of atoms so the defects are included. Using this new equation, we've been able to model up to a million atoms, so we get closer to the real properties of a substance."

By offering a panoramic view of how substances behave in the real world, the theory gives scientists a tool for developing materials that can be used for designing new technologies. Car frames made from lighter, strong metal alloys, for instance, might make vehicles more energy efficient, and smaller, faster electronic devices might be produced using nanowires with diameters tens of thousands of times smaller than that of a human hair.

Paul Madden, a chemistry professor and provost of The Queen's College at Oxford University, who originally introduced Carter to this field of research, described the work as a "significant breakthrough" that could allow researchers to substantially expand the range of materials that can be studied in this manner. "This opens up a new class of material physics problems to realistic simulation," he said.

The new theory traces its lineage to the Thomas-Fermi equation, a concept proposed by Llewellyn Hilleth Thomas and Nobel laureate Enrico Fermi in 1927. The equation was a simple means of relating two fundamental characteristics of atoms and molecules. They theorized that the energy electrons possess as a result of their motion -- electron kinetic energy -- could be calculated based how the electrons are distributed in the material. Electrons that are confined to a small region have higher kinetic energy, for instance, while those spread over a large volume have lower energy.

Understanding this relationship is important because the distribution of electrons is easier to measure, while the energy of electrons is more useful in designing materials. Knowing the electron kinetic energy helps researchers determine the structure and other properties of a material, such as how it changes shape in response to physical stress. The catch was that Thomas and Fermi's concept was based on a theoretical gas, in which the electrons are spread evenly throughout. It could not be used to predict properties of real materials, in which electron density is less uniform.

The next major advance came in 1964, when another pair of scientists, Pierre Hohenberg and Walter Kohn, another Nobel laureate, proved that the concepts proposed by Thomas and Fermi could be applied to real materials. While they didn't derive a final, working equation for directly relating electron kinetic energy to the distribution of electrons, Hohenberg and Kohn laid the formal groundwork that proved such an equation exists. Scientists have been searching for a working theory ever since.

Carter began working on the problem in 1996 and produced a significant advance with two postdoctoral researchers in 1999, building on Hohenberg and Kohn's work. She has continued to whittle away at the problem since. "It would be wonderful if a perfect equation that explains all of this would just fall from the sky," she said. "But that isn't going to happen, so we've kept searching for a practical solution that helps us study materials."

In the absence of a solution, researchers have been calculating the energy of each atom from scratch to determine the properties of a substance. The laborious method bogs down the most powerful computers if more than a few hundred atoms are being considered, severely limiting the amount of a material and type of phenomena that can be studied.

Carter knew that using the concepts introduced by Thomas and Fermi would be far more efficient, because it would avoid having to process information on the state of each and every electron.

As they worked on the problem, Carter and Chen Huang, a doctoral student in physics, concluded that the key to the puzzle was addressing a disparity observed in Carter's earlier work. Carter and her group had developed an accurate working model for predicting the kinetic energy of electrons in simple metals. But when they tried to apply the same model to semiconductors -- the conductive materials used in modern electronic devices -- their predictions were no longer accurate.

"We needed to find out what we were missing that made the results so different between the semiconductors and metals," Huang said. "Then we realized that metals and semiconductors respond differently to electrical fields. Our model was missing this."

In the end, Huang said, the solution was a compromise. "By finding an equation that worked for these two types of materials, we found a model that works for a wide range of materials."

Their new model, published online Jan. 26 in Physical Review B, a journal of the American Physical Society, provides a practical method for predicting the kinetic energy of electrons in semiconductors from only the electron density. The research was funded by the National Science Foundation.

Coupled with advances published last year by Carter and Linda Hung, a graduate student in applied and computational mathematics, the new model extends the range of elements and quantities of material that can be accurately simulated.

The researchers hope that by moving beyond the concepts introduced by Thomas and Fermi more than 80 years ago, their work will speed future innovations. "Before people could only look at small bits of materials and perfect crystals," Carter said. "Now we can accurately apply quantum mechanics at scales of matter never possible before."

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Surprise! Neural Mechanism May Underlie an Enhanced Memory for the Unexpected

Surprise! Neural Mechanism May Underlie an Enhanced Memory for the Unexpected

  9:06:00 AM    Science Lover

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The human brain excels at using past experiences to make predictions about the future. However, the world around us is constantly changing, and new events often violate our logical expectations.

The element of surprise appears to have a big effect on our ability to remember. Researchers have discovered that unexpected stimuli enhanced an early and a late electrical potential in the hippocampus and the late signal was associated with a memory for the unexpected picture. (Credit: iStockphoto/Rosemarie Gearhart)

"We know these unexpected events are more likely to be remembered than predictable events, but the underlying neural mechanisms for these effects remain unclear," says lead researcher, Dr. Nikolai Axmacher, from the University of Bonn in Germany.

Dr. Axmacher and colleagues, whose new study is published by Cell Press in the February 25 issue of the journal Neuron, investigated the relationship between novelty processing and memory formation in two key brain structures, the hippocampus, and the nucleus accumbens. The hippocampus plays a key role in memory formation while the nucleus accumbens is involved in processing rewards and novel information. Previous work had suggested that information transfer between these structures may be associated with enhanced memory for unexpected items or events.

Obtaining direct information on the electrical activity of these structures deep in the brain is usually impossible in humans. However, the researchers used the opportunity to record from two groups of patients with electrodes implanted in these regions: Epilepsy patients awaiting surgical treatment of severe epilepsy, and patients with treatment-resistant depression undergoing deep-brain stimulation. Both groups of participants studied pictures of faces and houses in grayscale that were usually presented on a red or green background, respectively. Occasionally, a picture would have an "unexpected" configuration, such as a face on a green background. Subjects were subsequently tested for their memory of the expected and unexpected items.

The researchers discovered that unexpected stimuli enhanced an early and a late electrical potential in the hippocampus and the late signal was associated with a memory for the unexpected picture. In the nucleus accumbens, there was only a late potential which was larger during exposure to unexpected items. "Our findings support the idea that hippocampal activity may initially signal the occurrence of an unexpected event and that the nucleus accumbens may influence subsequent processing which serves to promote memory encoding," explains Dr. Axmacher.

The authors are careful to point out that one limitation of their study is that the recordings from the hippocampus and nucleus accumbens came from two separate groups of subjects, so their data provide an indirect measure of the functional connectivity between these two brain areas. However, their findings do provide fascinating new insight into this complex brain circuit. "Taken together, these are the first results that speak to the relative timing of expectation effects in different regions of the human brain, and they support models of accumbens-hippocampus interactions during encoding of unexpected events," concludes Dr. Axmacher.

The researchers include Nikolai Axmacher, University of Bonn, Bonn, Germany, University of California, Davis, Davis, CA; Michael X. Cohen, University of Amsterdam, Amsterdam, The Netherlands, University of Arizona, Tucson, AZ; Juergen Fell, University of Bonn, Bonn, Germany; Sven Haupt, University of Bonn, Bonn, Germany; Matthias Dumpelmann, Epilepsy Center, University Hospital Freiburg, Freiburg, Germany; Christian E. Elger, University of Bonn, Bonn, Germany, University of California, Davis, Davis, CA; Thomas E. Schlaepfer, University of Bonn, Bonn, Germany, The Johns Hopkins University, Baltimore, MD; Doris Lenartz, University of Cologne, Koln, Germany; Volker Sturm, University of Cologne, Koln, Germany; and Charan Ranganath, University of California, Davis, Davis, CA.

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Nanotechnology Sparks Energy Storage on Paper and Cloth

Nanotechnology Sparks Energy Storage on Paper and Cloth

  10:08:00 PM    Science Lover

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By dipping ordinary paper or fabric in a special ink infused with nanoparticles, Stanford engineer Yi Cui has found a way to cheaply and efficiently manufacture lightweight paper batteries and supercapacitors (which, like batteries, store energy, but by electrostatic rather than chemical means), as well as stretchable, conductive textiles known as "eTextiles" -- capable of storing energy while retaining the mechanical properties of ordinary paper or fabric.

While the technology is still new, Cui's team has envisioned numerous functional uses for their inventions. Homes of the future could one day be lined with energy-storing wallpaper. Gadget lovers would be able to charge their portable appliances on the go, simply plugging them into an outlet woven into their T-shirts. Energy textiles might also be used to create moving-display apparel, reactive high-performance sportswear and wearable power for a soldier's battle gear.

The key ingredients in developing these high-tech products are not visible to the human eye. Nanostructures, which can be assembled in patterns that allow them to transport electricity, may provide the solutions to a number of problems encountered with electrical storage devices currently available on the market.

The type of nanoparticle used in the Cui group's experimental devices varies according to the intended function of the product -- lithium cobalt oxide is a common compound used for batteries, while single-walled carbon nanotubes, or SWNTs, are used for supercapacitors.

Cui, an assistant professor of materials science and engineering at Stanford, leads a research group that investigates new applications of nanoscale materials. The objective, said Cui, is not only to supply answers to theoretical inquiries but also to pursue projects with practical value. Recently, his team has focused on ways to integrate nanotechnology into the realm of energy development.

"Energy storage is a pretty old research field," said Cui. "Supercapacitors, batteries -- those things are old. How do you really make a revolutionary impact in this field? It requires quite a dramatic difference of thinking."

While electrical energy storage devices have come a long way since Alessandro Volta debuted the world's first electrical cell in 1800, the technology is facing yet another revolution. Current methods of manufacturing energy storage devices can be capital intensive and environmentally hazardous, and the end products have noticeable performance constraints -- conventional lithium ion batteries have a limited storage capacity and are costly to manufacture, while traditional capacitors provide high power but at the expense of energy storage capacity.

With a little help from new science, the batteries of the future may not look anything like the bulky metal units we've grown accustomed to. Nanotechnology is favored as a remedy both for its economic appeal and its capability to improve energy performance in devices that integrate it. Replacing the carbon (graphite) anodes found in lithium ion batteries with anodes of silicon nanowires, for example, has the potential to increase their storage capacity by 10 times, according to experiments conducted by Cui's team.

Silicon had previously been recognized as a favorable anode material because it can hold a larger amount of lithium than carbon. But applications of silicon were limited by its inability to sustain physical stress -- namely, the fourfold volume increase that silicon undergoes when lithium ions attach themselves to a silicon anode in the process of charging a battery, as well as the shrinkage that occurs when lithium ions are drawn out as it discharges. The result was that silicon structures would disintegrate, causing anodes of this material to lose much if not all of their storage capacity.

Cui and collaborators demonstrated in previous publications in Nature, Nanotechnology and Nano Letters that the use of silicon nanowire battery electrodes, mechanically capable of withstanding the absorption and discharge of lithium ions, was one way to sidestep the problem.

The findings hold promise for the development of rechargeable lithium batteries offering a longer life cycle and higher energy capacity than their contemporaries. Silicon nanowire technology may one day find a home in electric cars, portable electronic devices and implantable medical appliances.

Cui now hopes to direct his research toward studying both the "hard science" behind the electrical properties of nanomaterials and designing real-world applications.

"This is the right time to really see what we learn from nanoscience and do practical applications that are extremely promising," said Cui. "The beauty of this is, it combines the lowest cost technology that you can find to the highest tech nanotechnology to produce something great. I think this is a very exciting idea … a huge impact for society."

The Cui group's latest research on energy storage devices was detailed in papers published in the online editions of the Proceedings of the National Academy of Sciences in December 2009 ("Highly Conductive Paper for Energy-Storage Devices") and Nano Letters in January 2010 ("Stretchable, Porous and Conductive Energy Textiles").

Cui's presented his talk at the symposium "Nanotechnology: Will Nanomaterials Revolutionize Energy Applications?" at the San Diego Convention Center.

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Microsoft Threw Out the Playbook for Windows Phone 7

Microsoft Threw Out the Playbook for Windows Phone 7

  12:54:00 AM    Science Lover

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One of the biggest stories of the Mobile World Conference was the unveiling--finally--of Windows Mobile 7, rebranded as Windows Phone 7. The story within the story is how Microsoft abandoned the foundation established with the waning Windows Mobile platform, went back to the drawing board, and started from scratch for the latest incarnation of its mobile operating system.

The result is a completely new mobile platform from Microsoft which, at least from initial feedback and reviews, seems to be worthy of further consideration once Windows Phone 7 devices start hitting the streets.

Given the delays experienced by Microsoft in developing Windows Phone 7, expectations were high. Any minor, incremental improvement on the existing platform would have been virtually guaranteed to fail.

Microsoft's approach with Windows Phone 7 seems to borrow some from the Apple business model that has proven so successful with the iPhone. Like Google, with the Nexus One, Microsoft is reining in oversight of the hardware for Windows Phone 7 devices.

Microsoft has been accused of stealing a variety of design elements and features from Apple over the decades, but one thing it has steered clear of is emulating Apple's strict control of the end-to-end user experience. However, with Windows Phone 7, Microsoft seems to be embracing that philosophy to some degree.

Traditionally, the best Windows Mobile phones have been the devices built by HTC, and the reason they have been the best is because HTC took the Windows Mobile platform as a foundation, and branded it with its own unique design and interface elements. With Windows Phone 7, Microsoft has spelled out strict hardware and software design guidelines that will restrict such unique development by HTC, but hopefully deliver a more consistent experience for Windows Phone 7 users regardless of manufacturer.

By exerting more control over the hardware and software specifications, Microsoft can ensure that apps developed for Windows Phone 7 will not only work, but will work the same way, across all Windows Phone 7 devices. That level of consistency across Windows Phone 7 devices will help to increase adoption and improve perception of the Windows Phone 7 platform.

What Google seems to have learned from Apple--the same lesson that Microsoft appears to be grasping as well--is that maintaining control of the end-to-end user experience creates a more stable environment for developers to work with, and enables it (Google, Microsoft, or Apple as the case may be) to maximize the potential of the operating system without being handicapped by variations in capabilities from one handset to the next.

Of course, one of the things customers have come to expect from Microsoft is a more open and flexible platform than what Apple offers. Users want the ability to configure and customize their Windows devices--whether PC's or smartphones--and typically abhor the sort of "dummy-proof-our-way-or-the-highway" approach taken by Apple.

IT administrators enjoy the increased flexibility and capabilities of a more open platform like Windows Phone 7 or Android. One of the issues standing in the way of Apple iPhone adoption in the enterprise is the lack of control provided for IT administrators to be able to configure and manage the devices the way they would like to.

Businesses stand to benefit from the more consistent user experience of Windows Phone 7 as well, though. Rather than having to test and develop for each individual Windows Mobile handset in use, any configuration settings or custom apps will be able to function regardless of the Windows Phone 7 devices in use.

Windows Phone 7 appears to be a significant departure from previous Windows Mobile operating systems. At first glance it seems the Microsoft is heading in the right direction and could recapture some of the lost market share of the waning Windows Mobile platform. We'll have to wait until the Windows Phone 7 devices hit the streets to see how it really plays out.

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New Generation of Neuro-Computer Develop by Computer Scientists

New Generation of Neuro-Computer Develop by Computer Scientists

  7:54:00 PM    Science Lover

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Intelligent machines that not only think for themselves but also actively learn are the vision of researchers of the Institute for Theoretical Science (IGI) at Graz University of Technology.

They have been co-ordinating the European Union research project "Brain-i-Nets" (Novel Brain Inspired Learning Paradigms for Large-Scale Neuronal Networks) for three years, and are launching a three-day meeting of the participating researchers in Graz. The scientists want to design a new generation of neuro-computers based on the principles of calculation and learning mechanisms found in the brain, and at the same time gain new knowledge about the brain's learning mechanisms.

The human brain consists of a network of several billion nerve cells. These are joined together by independent connections called synapses. Synapses are changing all the time -- something scientists name synaptic plasticity. This highly complex system represents a basis for independent thinking and learning. But even today there are still many open questions for researchers.

"In contrast to today's computers, the brain doesn't carry out a set programme but rather is always adapting functions and reprogramming them anew. Many of these effects have not been explained," comments IGI head Wolfgang Maass together with project co-ordinator Robert Legenstein. In co-operation with neuroscientists and physicists, and with the help of new experimental methods, they want to research the mechanisms of synaptic plasticity in the organism.

Revolutionising the information society

The researchers are hoping to gain new knowledge from this research about the learning mechanisms in the human brain. They want to use this knowledge of learning mechanisms to develop new learning methods for artificial systems which process information. The scientists' long-term goal is to develop adaptive computers together which have the potential to revolutionise today's information society.

The three-year project is financed by the EU funding framework "Future Emerging Technologies" (FET), which supports especially innovative and visionary approaches in information technology. International experts chose only nine out of the 176 applications, among which was "Brain-i-Nets." Partners of the research initiative worth 2.6m euro include University College London, the Ecole Polytechnique Federale de Lausanne, the French Centre National de la Recherche Scientifique, Ruprecht-Karls-Universität Heidelberg und the University of Zurich.

For more information, visit: http://www.brain-i-nets.eu

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Photosynthesis: A New Source of Electrical Energy? Biofuel Cell Works in Cactus

Photosynthesis: A New Source of Electrical Energy? Biofuel Cell Works in Cactus

  1:08:00 AM    Science Lover

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Scientists in France have transformed the chemical energy generated by photosynthesis into electrical energy by developing a novel biofuel cell. The advance offers a new strategy to convert solar energy into electrical energy in an environmentally-friendly and renewable manner. In addition, the biofuel cell could have important medical applications.

Biofuel cell inserted in a cactus and graph showing the course of electrical current as a function of illumination of the cactus (black: glucose, red: O2)

These findings have just been published in the journal Analytical Chemistry.

Photosynthesis is the process by which plants convert solar energy into chemical energy. In the presence of visible light, carbon dioxide (CO₂) and water (H₂0) are transformed into glucose and O₂ during a complex series of chemical reactions. Researchers at the Centre de Recherche Paul Pascal (CNRS) developed a biofuel cell that functions using the products of photosynthesis (glucose and O₂) and is made up of two enzyme-modified electrodes.

The cell was then inserted in a living plant, in this case a cactus. Once the electrodes, highly sensitive to O₂ and glucose, had been implanted in the cactus leaf, the scientists succeeded in monitoring the real-time course of photosynthesis in vivo. They were able to observe an increase in electrical current when a desk lamp was switched on, and a reduction when it was switched off. During these experiments, the scientists were also able to make the first ever observation of the real-time course of glucose levels during photosynthesis. This method could offer a new means of better understanding the mechanisms of photosynthesis.

Furthermore, the researchers showed that a biofuel cell inserted in a cactus leaf could generate power of 9 μW per cm². Because this yield was proportional to light intensity, stronger illumination accelerated the production of glucose and O₂ (photosynthesis), so more fuel was available to operate the cell. In the future, this system could ultimately form the basis for a new strategy for the environmentally-friendly and renewable transformation of solar energy into electrical energy.

Alongside these results, the initial objective of this work was to develop a biofuel cell for medical applications. This could then function autonomously under the skin (in vivo), drawing chemical energy from the oxygen-glucose couple that is naturally present in physiological fluids. It could thus provide power for implanted medical devices such as, for example, autonomous subcutaneous sensors to measure glucose levels in diabetic patients.

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Artificial Foot Recycles Energy for Easier Walking

Artificial Foot Recycles Energy for Easier Walking

  1:01:00 AM    Science Lover

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An artificial foot that recycles energy otherwise wasted in between steps could make it easier for amputees to walk, its developers say.

Developers say that an artificial foot that recycles energy otherwise wasted in between steps could make it easier for amputees to walk. (Credit: Image courtesy of University of Michigan)

"For amputees, what they experience when they're trying to walk normally is what I would experience if I were carrying an extra 30 pounds," said Art Kuo, professor in the University of Michigan departments of Biomedical Engineering and Mechanical Engineering.

Compared with conventional prosthetic feet, the new prototype device significantly cuts the energy spent per step.

A paper about the device is published in the Feb. 17 edition of in the journal PLoS ONE. The foot was created by Kuo and Steve Collins, who was then a U-M graduate student. Now Collins is an associate research fellow at Delft University of Technology in the Netherlands.

The human walking gait naturally wastes energy as each foot collides with the ground in between steps.

A typical prosthesis doesn't reproduce the force a living ankle exerts to push off of the ground. As a result, test subjects spent 23 percent more energy walking with a conventional prosthetic foot, compared with walking naturally. To test how stepping with their device compared with normal walking, the engineers conducted their experiments with non-amputees wearing a rigid boot and prosthetic simulator.

In their energy-recycling foot, the engineers put the wasted walking energy to work enhancing the power of ankle push-off. The foot naturally captures the dissipated energy. A microcontroller tells the foot to return the energy to the system at precisely the right time.

Based on metabolic rate measurements, the test subjects spent 14 percent more energy walking in energy-recycling artificial foot than they did walking naturally. That's a significant decrease from the 23 percent more energy they used in the conventional prosthetic foot, Kuo says.

"We know there's an energy penalty in using an artificial foot," Kuo said. "We're almost cutting that penalty in half."

He explained how this invention differs from current technologies.

"All prosthetic feet store and return energy, but they don't give you a choice about when and how. They just return it whenever they want," Kuo said. "This is the first device to release the energy in the right way to supplement push-off, and to do so without an external power source."

Other devices that boost push-off power use motors and require large batteries.

Because the energy-recycling foot takes advantage of power that would otherwise be lost, it uses less than 1 Watt of electricity through a small, portable battery.

"Individuals with lower limb amputations, such as veterans of the conflicts in Iraq and Afghanistan or patients suffering from diabetes, often find walking a difficult task. Our new design may restore function and reduce effort for these users," Collins said. "With further progress, robotic limbs may yet beat their biological forerunners."

This paper demonstrates that the engineers' idea works. They are now testing the foot on amputees at the Seattle Veterans Affairs Medical Center. Commercial devices based on the technology are under development by an Ann Arbor company. This research was funded by the National Institutes of Health and the Department of Veterans Affairs.

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Diamond Nanowires for Quantum Computing?

Diamond Nanowires for Quantum Computing?

  1:54:00 AM    Science Lover

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Diamond Nanowire Device Could Lead to New Class of Diamond Nanomaterials Suitable for Quantum Cryptography, Quantum Computing, and Magnetic Field Imaging

By creating diamond-based nanowire devices, a team at Harvard has taken another step towards making applications based on quantum science and technology possible.

A diamond-based nanowire device. Researchers used a top-down nanofabrication technique to embed color centers into a variety of machined structures. By creating large device arrays rather than just "one-of-a-kind" designs, the realization of quantum networks and systems, which require the integration and manipulation of many devices in parallel, is more likely. (Credit: Illustrated by Jay Penni.)

The new device offers a bright, stable source of single photons at room temperature, an essential element in making fast and secure computing with light practical.

The finding could lead to a new class of nanostructured diamond devices suitable for quantum communication and computing, as well as advance areas ranging from biological and chemical sensing to scientific imaging.

Published in the February 14th issue of Nature Nanotechnology,researchers led by Marko Loncar, Assistant Professor of Electrical Engineering at the Harvard School of Engineering and Applied Sciences (SEAS), found that the performance of a single photon source based on a light emitting defect (color center) in diamond could be improved by nanostructuring the diamond and embedding the defect within a diamond nanowire.

Scientists, in fact, first began exploiting the properties of natural diamonds after learning how to manipulate the electron spin, or intrinsic angular momentum, associated with the nitrogen vacancy (NV) color center of the gem. The quantum (qubit) state can be initialized and measured using light.

The color center "communicates" by emitting and absorbing photons. The flow of photons emitted from the color center provides a means to carry the resulting information, making the control, capture, and storage of photons essential for any kind of practical communication or computation. Gathering photons efficiently, however, is difficult since color-centers are embedded deep inside the diamond.

"This presents a major problem if you want to interface a color center and integrate it into real-world applications," explains Loncar. "What was missing was an interface that connects the nano-world of a color center with macro-world of optical fibers and lenses."

The diamond nanowire device offers a solution, providing a natural and efficient interface to probe an individual color center, making it brighter and increasing its sensitivity. The resulting enhanced optical properties increases photon collection by nearly a factor of ten relative to natural diamond devices.

"Our nanowire device can channel the photons that are emitted and direct them in a convenient way," says lead-author Tom Babinec, a graduate student at SEAS.

Further, the diamond nanowire is designed to overcome hurdles that have challenged other state-of-the-art systems -- such as those based on fluorescent dye molecules, quantum dots, and carbon nanotubes -- as the device can be readily replicated and integrated with a variety of nano-machined structures.

The researchers used a top-down nanofabrication technique to embed color centers into a variety of machined structures. By creating large device arrays rather than just "one-of-a-kind" designs, the realization of quantum networks and systems, which require the integration and manipulation of many devices in parallel, is more likely.

"We consider this an important step and enabling technology towards more practical optical systems based on this exciting material platform," says Loncar. "Starting with these synthetic, nanostructured diamond samples, we can start dreaming about the diamond-based devices and systems that could one day lead to applications in quantum science and technology as well as in sensing and imaging."

Loncar and Babinec's co-authors included research scholar Birgit Hausmann, graduate student Yinan Zhang, and postdoctoral student Mughees Khan, all at SEAS; graduate student Jero Maze in the Department of Physics at Harvard; and faculty member Phil R. Hemmer at Texas A&M University.

The researchers acknowledge the following support: Nanoscale Interdisciplinary Research Team (NIRT) grant from National Science Foundation (NSF), the NSF-funded Nanoscale Science and Engineering Center at Harvard (NSEC); the Defense Advanced Research Projects Agency (DARPA); and a National Defense Science and Engineering Graduate Fellowship and National Science Foundation Graduate Fellowship. All devices have been fabricated at the Center for Nanoscale Systems (CNS) at Harvard.

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Nano-Gold Turns Light Into Electricity

Nano-Gold Turns Light Into Electricity

  1:15:00 AM    Science Lover

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Scientists Turn Light Into Electrical Current Using a Golden Nanoscale System

Material scientists at the Nano/Bio Interface Center of the University of Pennsylvania have demonstrated the transduction of optical radiation to electrical current in a molecular circuit. The system, an array of nano-sized molecules of gold, respond to electromagnetic waves by creating surface plasmons that induce and project electrical current across molecules, similar to that of photovoltaic solar cells.

Material scientists at the Nano/Bio Interface Center of the University of Pennsylvania have demonstrated the transduction of optical radiation to electrical current in a molecular circuit. (Credit: Dawn Bonnell, the University of Pennsylvania)

The results may provide a technological approach for higher efficiency energy harvesting with a nano-sized circuit that can power itself, potentially through sunlight. Recently, surface plasmons have been engineered into a variety of light-activated devices such as biosensors.

It is also possible that the system could be used for computer data storage. While the traditional computer processor represents data in binary form, either on or off, a computer that used such photovoltaic circuits could store data corresponding to wavelengths of light.

Because molecular compounds exhibit a wide range of optical and electrical properties, the strategies for fabrication, testing and analysis elucidated in this study can form the basis of a new set of devices in which plasmon-controlled electrical properties of single molecules could be designed with wide implications to plasmonic circuits and optoelectronic and energy-harvesting devices.

Dawn Bonnell, a professor of materials science and the director of the Nano/Bio Interface Center at Penn, and colleagues fabricated an array of light sensitive, gold nanoparticles, linking them on a glass substrate. Minimizing the space between the nanoparticles to an optimal distance, researchers used optical radiation to excite conductive electrons, called plasmons, to ride the surface of the gold nanoparticles and focus light to the junction where the molecules are connected. The plasmon effect increases the efficiency of current production in the molecule by a factor of 400 to 2000 percent, which can then be transported through the network to the outside world.

In the case where the optical radiation excites a surface plasmon and the nanoparticles are optimally coupled, a large electromagnetic field is established between the particles and captured by gold nanoparticles. The particles then couple to one another, forming a percolative path across opposing electrodes. The size, shape and separation can be tailored to engineer the region of focused light. When the size, shape and separation of the particles are optimized to produce a "resonant" optical antennae, enhancement factors of thousands might result.

Furthermore, the team demonstrated that the magnitude of the photoconductivity of the plasmon-coupled nanoparticles can be tuned independently of the optical characteristics of the molecule, a result that has significant implications for future nanoscale optoelectronic devices.

"If the efficiency of the system could be scaled up without any additional, unforeseen limitations, we could conceivably manufacture a one-amp, one-volt sample the diameter of a human hair and an inch long," Bonnell said.

The study, published in the current issue of the journal ACS Nano, was conducted by Bonnell, David Conklin and Sanjini Nanayakkara of the Department of Materials Science and Engineering in the School of Engineering and Applied Science at Penn; Tae-Hong Park of the Department of Chemistry in the School of Arts and Sceicnes at Penn; Parag Banerjee of the Department of Materials Science and Engineering at the University of Maryland; and Michael J. Therien of the Department of Chemistry at Duke University.

This work was supported by the Nano/Bio Interface Center, National Science Foundation, the John and Maureen Hendricks Energy Fellowship and the U.S. Department of Energy. 

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New Fiber Nanogenerators Could Lead to Electric Clothing

New Fiber Nanogenerators Could Lead to Electric Clothing

  1:33:00 AM    Science Lover

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In research that gives literal meaning to the term "power suit," University of California, Berkeley, engineers have created energy-scavenging nanofibers that could one day be woven into clothing and textiles.

Shown is a fiber nanogenerator on a plastic substrate created by UC Berkeley scientists. The nanofibers can convert energy from mechanical stresses and into electricity, and could one day be used to create clothing that can power small electronics. (Credit: Chieh Chang, UC Berkeley)

These nano-sized generators have "piezoelectric" properties that allow them to convert into electricity the energy created through mechanical stress, stretches and twists.

"This technology could eventually lead to wearable 'smart clothes' that can power hand-held electronics through ordinary body movements," said Liwei Lin, UC Berkeley professor of mechanical engineering and head of the international research team that developed the fiber nanogenerators.

Because the nanofibers are made from organic polyvinylidene fluoride, or PVDF, they are flexible and relatively easy and cheap to manufacture.

Although they are still working out the exact calculations, the researchers noted that more vigorous movements, such as the kind one would create while dancing the electric boogaloo, should theoretically generate more power. "And because the nanofibers are so small, we could weave them right into clothes with no perceptible change in comfort for the user," said Lin, who is also co-director of the Berkeley Sensor and Actuator Center at UC Berkeley.

The fiber nanogenerators are described in this month's issue of Nano Letters, a peer-reviewed journal published by the American Chemical Society.

The goal of harvesting energy from mechanical movements through wearable nanogenerators is not new. Other research teams have previously made nanogenerators out of inorganic semiconducting materials, such as zinc oxide or barium titanate. "Inorganic nanogenerators -- in contrast to the organic nanogenerators we created -- are more brittle and harder to grow in significant quantities," Lin said.

The tiny nanogenerators have diameters as small as 500 nanometers, or about 100 times thinner than a human hair and one-tenth the width of common cloth fibers. The researchers repeatedly tugged and tweaked the nanofibers, generating electrical outputs ranging from 5 to 30 millivolts and 0.5 to 3 nanoamps.

Furthermore, the researchers report no noticeable degradation after stretching and releasing the nanofibers for 100 minutes at a frequency of 0.5 hertz (cycles per second).

Lin's team at UC Berkeley pioneered the near-field electrospinning technique used to create and position the polymeric nanogenerators 50 micrometers apart in a grid pattern. The technology enables greater control of the placement of the nanofibers onto a surface, allowing researchers to properly align the fiber nanogenerators so that positive and negative poles are on opposite ends, similar to the poles on a battery.

Without this control, the researchers explained, the negative and positive poles might cancel each other out and reducing energy efficiency.

The researchers demonstrated energy conversion efficiencies as high as 21.8 percent, with an average of 12.5 percent.

"Surprisingly, the energy efficiency ratings of the nanofibers are much greater than the 0.5 to 4 percent achieved in typical power generators made from experimental piezoelectric PVDF thin films, and the 6.8 percent in nanogenerators made from zinc oxide fine wires," said the study's lead author, Chieh Chang, who conducted the experiments while he was a graduate student in mechanical engineering at UC Berkeley.

"We think the efficiency likely could be raised further," Lin said. "For our preliminary results, we see a trend that the smaller the fiber we have, the better the energy efficiency. We don't know what the limit is."

Other co-authors of the study are Yiin-Kuen Fuh, a UC Berkeley graduate student in mechanical engineering; Van H. Tran, a graduate student at the Technische Universität München (Technical University of Munich) in Germany; and Junbo Wang, a researcher at the Institute of Electronics at the Chinese Academy of Sciences in Beijing, China. The National Science Foundation and the Defense Advanced Research Projects Agency helped support this research.

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Is Twitter Fretting over Google Buzz?

Is Twitter Fretting over Google Buzz?

  6:58:00 PM    Science Lover

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Well, it looks like Twitter may be getting similar comeuppance. Google just announced Google Buzz and you can learn about it in the video above or in the TechCrunch article hot off the presses.

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Windows Phone 7: No Multitasking, Stricter Microsoft QA

Windows Phone 7: No Multitasking, Stricter Microsoft QA

  9:13:00 AM    Science Lover

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Later this month, Microsoft will most likely unveil Windows Mobile 7 Windows Phone 7 at the Mobile World Congress. Rumours abound, and the latest set of rumours paint a rather dramatic turnaround for Microsoft's mobile platform - no more multitasking, application distribution limited to official channels, and a whole lot more.

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Liquid Phone with Qualcomm Snapdragon Processor

Liquid Phone with Qualcomm Snapdragon Processor

  6:15:00 AM    Science Lover

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Acer has brought a new liquid phone in India. It’s really liquid due to its unique feature which differentiates it from the other phones. This phone has the world’s first Qualcomm Snapdragon processor and is based on the first Android 1.6 high definition smart phone. It delivers real time communication as well as content which are location aware. This smart device brings forth a unique combination of high quality performance as well as bold style.

This high defining smart phone combines the cutting edge technologies; software innovation as well as ultra-fluid user interfaces so that users can get a completely new experience with this phone. Unique set of features developed by Acer and its partners would include a new user interface as well as improved power management systems. This enhanced power management system would help the user to achieve longer battery autonomy.

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Meet Robonaut – the world's most skillful bot who can help out auto workers on Earth and lend a hand to astronauts in space

Meet Robonaut – the world's most skillful bot who can help out auto workers on Earth and lend a hand to astronauts in space

  3:28:00 PM    Science Lover

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NASA and an American car company are working together to accelerate development of the next generation of robots and related technologies for use in the automotive and aerospace industries.

Engineers and scientists from NASA and General Motors worked together to build a new humanoid robot capable of working side by side with people. Using leading edge control, sensor and vision technologies, future robots could assist astronauts during hazardous space missions and help GM build safer cars and plants.

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Microsoft Office 2010 RC available for download

Microsoft Office 2010 RC available for download

  7:34:00 PM    Science Lover

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Microsoft just sent an e-mail stating that Office 2010 Release Candidate (RC) is now available for download to Connect users. Users beta-testing the suite can go ahead to Microsoft Connect and download the latest builds – v4734.1000 for 2010 client and build v4730.1010 for server products.

However, one important thing to know is that you’ll need to request new product key as beta keys won’t be allowed to activate the RC.

This probably will be the only RC as a RTM build is expected to hit this June.

Microsoft Connect

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Superconducting Hydrogen

Superconducting Hydrogen

  7:02:00 PM    Science Lover

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Physicists have long wondered whether hydrogen, the most abundant element in the universe, could be transformed into a metal and possibly even a superconductor -- the elusive state in which electrons can flow without resistance.

Periodic table detail of hydrogen. (Credit: iStockphoto/David Freund)

 

They have speculated that under certain pressure and temperature conditions hydrogen could be squeezed into a metal and possibly even a superconductor, but proving it experimentally has been difficult. High-pressure researchers, including Carnegie's Ho-kwang (Dave) Mao, have now modeled three hydrogen-dense metal alloys and found there are pressure and temperature trends associated with the superconducting state -- a huge boost in the understanding of how this abundant material could be harnessed.

The study is published in the January 25, 2010, early, on-line edition of the Proceedings of the National Academy of Sciences.

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Gene Function Discovery: Guilt by Association

Gene Function Discovery: Guilt by Association

  9:33:00 AM    Science Lover

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Scientists have created a new computational model that can be used to predict gene function of uncharacterized plant genes with unprecedented speed and accuracy. The network, dubbed AraNet, has over 19,600 genes associated to each other by over 1 million links and can increase the discovery rate of new genes affiliated with a given trait tenfold. It is a huge boost to fundamental plant biology and agricultural research.

Each line of this AraNet network represents a functional link between two genes. The colors indicate the strength of the link using a red-blue heat map scheme.The image includes about 100,000 functional links made among about 10,000 Arabidopsis genes. (Credit: Image courtesy Sue Rhee)

Despite immense progress in functional characterization of plant genomes, over 30% of the 30,000 Arabidopsis genes have not been functionally characterized yet. Another third has little evidence regarding their role in the plant.

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