How Neurons Decide How to Transmit Information

How Neurons Decide How to Transmit Information

  11:39:00 PM    Science Lover

---

There are billions of neurons in the brain and at any given time tens of thousands of these neurons might be trying to send signals to one another. Much like a person trying to be heard by his friend across a crowded room, neurons must figure out the best way to get their message heard above the din.

Inhibitory circuits in the olfactory bulb use a novel, 
time-scale dependent strategy to mediate how neurons 
choose between encoding and propagating 
information. (Credit: Sonya Giridhar)

Researchers from the Center for the Neural Basis of Cognition, a joint program between Carnegie Mellon University and the University of Pittsburgh, have found two ways that neurons accomplish this, establishing a fundamental mechanism by which neurons communicate. The findings have been published in an online early edition of Proceedings of the National Academy of Sciences (PNAS).

"Neurons face a universal communications conundrum. They can speak together and be heard far and wide, or they can speak individually and say more. Both are important. We wanted to find out how neurons choose between these strategies," said Nathan Urban, the Dr. Frederick A. Schwertz Distinguish Professor of Life Sciences and head of the Department of Biological Sciences at CMU.

Neurons communicate by sending out electrical impulses called action potentials or "spikes." These spikes code information much like a version of Morse code with only dots and no dashes. Groups of neurons can choose to communicate information in one of two ways: by spiking simultaneously or by spiking separately.

To find out how the brain decided which method to use to process a sensory input, the researchers looked at mitral cell neurons in the brain's olfactory bulb -- the part of the brain that sorts out smells and a common model for studying global information processing. Using slice electrophysiology and computer simulations, the researchers found that the brain had a clever strategy for ensuring that the neurons' message was being heard.

Over the short time scale of a few milliseconds, the brain engaged its inhibitory circuitry to make the neurons fire in synchrony. This simultaneous, correlated firing creates a loud, but simple, signal. The effect was much like a crowd at a sporting event chanting, "Let's go team!" Over short time intervals, individual neurons produced the same short message, increasing the effectiveness with which activity was transmitted to other brain areas. The researchers say that in both human and neuronal communication alike, this collective communication works well for simple messages, but not for longer or more complex messages that contain more intricate information.

The neurons studied used longer timescales (around one second) to convey these more complex concepts. Over longer time intervals, the inhibitory circuitry generated a form of competition between neurons, so that the more strongly activated neurons silenced the activity of weakly activated neurons, enhancing the differences in their firing rates and making their activity less correlated. Each neuron was able to communicate a different piece of information about the stimulus without being drowned out by the chatter of competing neurons. It would be like being in a group where each person spoke in turn. The room would be much quieter than a sports arena and the immediate audience would be able to listen and learn much more complex information.

Researchers believe that the findings can be applied beyond the olfactory system to other neural systems, and perhaps even be used in other biological systems.

"Across biology, from genetics to ecology, systems must simultaneously complete multiple functions. The solution we found in neuroscience can be applied to other systems to try to understand how they manage competing demands," Urban said.

Co-authors of the study include Brent Doiron, assistant professor of mathematics at the University of Pittsburgh, and Sonya Giridhar, a doctoral student in the Center for Neuroscience at Pitt. Both are members of the Center for the Neural Basis of Cognition.

The study was funded by the National Institute on Deafness and Other Communications Disorders, the National Institutes of Health and the National Science Foundation.

Read More

Smaller Particles Could Make Solar Panels More Efficient

Smaller Particles Could Make Solar Panels More Efficient

  1:24:00 AM    Science Lover

---

Studies done by Mark Lusk and colleagues at the Colorado School of Mines could significantly improve the efficiency of solar cells. Their latest work describes how the size of light-absorbing particles--quantum dots--affects the particles' ability to transfer energy to electrons to generate electricity.

Illustration of multiple-exciton generation (MEG), a 
theory that suggests it is possible for an electron that has 
absorbed light energy, called an exciton, to transfer that 
energy to more than one electron, resulting in more electricity 
from the same amount of absorbed light. The left side shows an 
electron promoted to a high energy state (blue) plus the "hole" 
vacated by the electron (red). The right side shows the original 
exciton (now dark green/red) and a new exciton (light green
 /orange) after MEG. The top image shows a conceptualized 
version of the idea, while the bottom shows an actual exciton 
and bi-exciton using the same color scheme. (Credit: Mark 
T. Lusk, Department of Physics, Colorado School of Mines)

The results are published in the April issue of the journal ACS Nano.
 
The advance provides evidence to support a controversial idea, called multiple-exciton generation (MEG), which theorizes that it is possible for an electron that has absorbed light energy, called an exciton, to transfer that energy to more than one electron, resulting in more electricity from the same amount of absorbed light.

Quantum dots are human-made atoms that confine electrons to a small space. They have atomic-like behavior that results in unusual electronic properties on a nanoscale. These unique properties may be particularly valuable in tailoring the way light interacts with matter.

Experimental verification of the link between MEG and quantum dot size is a hot topic due to a large degree of variation in previously published studies. The ability to generate an electrical current following MEG is now receiving a great deal of attention because this will be a necessary component of any commercial realization of MEG.

For this study, Lusk and collaborators used a National Science Foundation (NSF)-supported high performance computer cluster to quantify the relationship between the rate of MEG and quantum dot size.

They found that each dot has a slice of the solar spectrum for which it is best suited to perform MEG and that smaller dots carry out MEG for their slice more efficiently than larger dots. This implies that solar cells made of quantum dots specifically tuned to the solar spectrum would be much more efficient than solar cells made of material that is not fabricated with quantum dots.


According to Lusk, "We can now design nanostructured materials that generate more than one exciton from a single photon of light, putting to good use a large portion of the energy that would otherwise just heat up a solar cell."

The research team, which includes participation from the National Renewable Energy Laboratory, is part of the NSF-funded Renewable Energy Materials Research Science and Engineering Center at the Colorado School of Mines in Golden, Colo. The center focuses on materials and innovations that will significantly impact renewable energy technologies. Harnessing the unique properties of nanostructured materials to enhance the performance of solar panels is an area of particular interest to the center.

"These results are exciting because they go far towards resolving a long-standing debate within the field," said Mary Galvin, a program director for the Division of Materials Research at NSF. "Equally important, they will contribute to establishment of new design techniques that can be used to make more efficient solar cells."

Read More

Acupuncture for Pain No Better Than Placebo - And Not Without Harm, Study Finds

Acupuncture for Pain No Better Than Placebo - And Not Without Harm, Study Finds

  5:50:00 PM    Science Lover

---

Although acupuncture is commonly used for pain control, doubts about its effectiveness and safety remain. Investigators from the Universities of Exeter & Plymouth (Exeter, UK) and the Korea Institute of Oriental Medicine (Daejeon, South Korea) critically evaluated systematic reviews of acupuncture as a treatment of pain in order to explore this question. Reporting in the April 2011 issue of PAIN®, they conclude that numerous systematic reviews have generated little truly convincing evidence that acupuncture is effective in reducing pain, and serious adverse effects continue to be reported.

Numerous systematic reviews have generated little truly 
convincing evidence that acupuncture is effective in reducing 
pain, and serious adverse effects continue to be reported, say 
scientists in a new article. (Credit: iStockphoto)

"Many systematic reviews of acupuncture for pain management are available, yet they only support few indications, and contradictions abound," commented lead investigator Professor Edzard Ernst, MD, PhD, Laing Chair in Complementary Medicine, Peninsula Medical School, Universities of Exeter & Plymouth, UK. "Acupuncture remains associated with serious adverse effects. One might argue that, in view of the popularity of acupuncture, the number of serious adverse effects is minute. We would counter, however, that even one avoidable adverse event is one too many. The key to making progress would be to train all acupuncturists to a high level of competency."

Researchers carefully identified and critically examined systematic reviews of acupuncture studies for pain relief and case reviews reporting adverse effects. Reviews were defined as systematic if they included an explicit Methods section describing the search strategy and inclusion/exclusion criteria. Systematic reviews had to focus on the effectiveness of any type of acupuncture for pain. Of the 266 articles found, 56 were categorized as acceptable systematic reviews.

The authors observe that recent results from high-quality randomized controlled trials have shown that various forms of acupuncture, including so-called "sham acupuncture," during which no needles actually penetrate the skin, are equally effective for chronic low back pain, and more effective than standard care. In these and other studies, the effects were attributed to such factors as therapist conviction, patient enthusiasm or the acupuncturist's communication style.

If even sham acupuncture is as good as or better than standard care, then what is the harm? The answer lies in the adverse effect case studies. These studies were grouped into three categories: Infection (38 cases), trauma (42 cases) and other adverse effects (13 cases). Many of these adverse side effects are not intrinsic to acupuncture, but rather result from malpractice of acupuncturists. The most frequently reported complications included pneumothorax, (penetration of the thorax) and bacterial and viral infections. Five patients died after their treatment.

In an accompanying commentary, Harriet Hall, MD, states her position forcefully: "Importantly, when a treatment is truly effective, studies tend to produce more convincing results as time passes and the weight of evidence accumulates. When a treatment is extensively studied for decades and the evidence continues to be inconsistent, it becomes more and more likely that the treatment is not truly effective. This appears to be the case for acupuncture. In fact, taken as a whole, the published (and scientifically rigorous) evidence leads to the conclusion that acupuncture is no more effective than placebo."

Read More

Teens: Power to Resist Blooms in Brain

Teens: Power to Resist Blooms in Brain

  9:55:00 AM    Science Lover

---

Just when children are faced with intensifying peer pressure to misbehave, regions of the brain are actually blossoming in a way that heighten the ability to resist risky behavior, report researchers at three West Coast institutions.

Researchers compared the fMRI results from age 10 to age 13, finding that activity increased significantly in the ventral striatum and the ventral medial portion of the prefrontal cortex over this three-year period. (Credit: Image courtesy of University of Oregon)

The findings -- detailed in the March 10 issue of the journal Neuron -- may give parents a sigh of relief regarding their kids as they enter adolescence and pay more attention to their friends. However, the research provides scientists with basic insight about the brain's wiring, rather than direct clinical relevance for now.

In the study, 24 girls and 14 boys from ethnically and socioeconomically diverse backgrounds underwent functional magnetic resonance imaging (fMRI) scans twice, at ages 10 and 13, the latter representing when children have moved into early adolescence. Each time, they were presented with photos of faces making neutral, angry, fearful, happy and sad emotional expressions.

Non-invasive fMRI, when focused on the brain, measures blood flow changes using a magnetic field and radio frequency pulses, producing detailed images that provide scientists with information about brain activity or help medical staff diagnose disease.

Researchers compared the fMRI results from age 10 to age 13, finding that activity increased significantly in the ventral striatum and the ventral medial portion of the prefrontal cortex over this three-year period. In addition to the scans, the researchers considered the children's self-reports on their ability to resist peer influences and engagement in risky or delinquent behavior.

The most enhanced response occurred in the ventral striatum, a brain region most frequently associated with reward-related processing. Over time, increases in brain activity there correlated with increases in children's resistance to peer influence.

"This is a complex point, because people tend to think of adolescence as the time when teenagers are really susceptible to peer pressure," said Jennifer H. Pfeifer, professor of psychology at the University of Oregon. "That is the case, but in addition to that added susceptibility they are also improving their ability to resist it. It's just that peer pressure is increasing because they spend a lot more time with peers during this time and less time with family. So it is a good thing that resistance to such influences is actually strengthening in their brains."

This study, which researchers believed to be the first to report longitudinal fMRI findings about changes in the way the brain processes emotion during this critical time of brain development, appears to fit into a growing body of evidence that ventral striatum development during early adolescence is critical to emotional regulation carried out by the brain's prefrontal circuitry, the researchers concluded.

"This is basic research that hopefully is laying the foundation for future studies with even more clinical relevance," said Pfeifer, director of the Developmental Social Neuroscience Lab. "We really have a lot to learn about how the brain responds to really basic emotional stimuli across development."

There was a surprise finding that deserves more study, though, Pfeifer said. Responses in the amygdala -- a small almond-shaped mass centrally located deep in the brain -- showed significant increases during this period only to the sad faces.

The amygdala plays a major role in emotional reactivity and indexing the salience of things in the environment. It's possible, Pfeifer said, that this response to sad faces could somehow be tied to the emergence of depression, especially in girls.

"This response in the amygdala raises questions we hope to pursue," she said. "The span from age 9 to 13 is critical in pubertal development. How do individual differences apply here? Identifying this response to 'sadness' in the amygdala opens the door to thinking about how changes in emotional reactivity might be related to the increase in depression that we see as kids enter puberty. Rates of depression are particularly enhanced for teen girls. Is this increased response to sad faces somehow part of that?"

Based on results of the new study, she added, "I think what we know about the ventral striatum may be poised to undergo a transformation over the next several years."

Six co-authors on the study with Pfeifer were: Carrie L. Masten of the Center for Mind and Brain at the University of California, Davis; William E. Moore III and Tasha M. Oswald, both doctoral students in the UO psychology department; John C. Mazziotta of the Ahmanson-Lovelace Brain Mapping Center at the University of California, Los Angeles; and Marco Iacoboni and Mirella Dapretto, both colleagues of Mazziotta and also with the FPR-UCLA Center for Culture, Brain, and Development at UCLA.

The National Center for Research Resources of the National Institutes of Health supported the research through three grants to the collaborating scientists.

Read More

A Search Engine for the Human Body

A Search Engine for the Human Body

  2:12:00 AM    Science Lover

---

Microsoft software recognizes organs and other structures in medical images.

A new search tool developed by researchers at Microsoft indexes medical images of the human body, rather than the Web. On CT scans, it automatically finds organs and other structures, to help doctors navigate in and work with 3-D medical imagery.

Inside out: A close up of a CT processed by new software from Microsoft.
Credit: Microsoft Research

CT scans use X-rays to capture many slices through the body that can be combined to create a 3-D representation. This is a powerful tool for diagnosis, but it's far from easy to navigate, says Antonio Criminisi, who leads a group at Microsoft Research Cambridge, U.K., that is attempting to change that. "It is very difficult even for someone very trained to get to the place they need to be to examine the source of a problem," he says.

When a scan is loaded into Criminisi's software, the program indexes the data and lists the organs it finds at the side of the screen, creating a table of hyperlinks for the body. A user can click on, say, the word "heart" and be presented with a clear view of the organ without having to navigate through the imagery manually.

Once an organ of interest has been found, a 2-D and an enhanced 3-D view of structures in the area are shown to the user, who can navigate by touching the screen on which the images are shown. A new scan can also be automatically and precisely matched up alongside a past one from the same patient, making it easy to see how a condition has progressed or regressed.

Criminisi's software uses the pattern of light and dark in the scan to identify particular structures; it was developed by training machine-learning algorithms to recognize features in hundreds of scans in which experts had marked the major organs. Indexing a new scan takes only a couple of seconds, says Criminisi. The system was developed in collaboration with doctors at Addenbrookes Hospital in Cambridge, U.K.

The Microsoft research group is exploring the use of gestures and voice to control the system. They can plug in the Kinect controller, ordinarily used by gamers to control an Xbox with body movements, so that surgeons can refer to imagery in mid-surgery without compromising their sterile gloves by touching a keyboard, mouse, or screen.

Body search: This CT image shows organs and other features identified by the Microsoft software. A list of these features appears at left.
Credit: Microsoft Research

Kenji Suzuki an assistant professor at the University of Chicago, whose research group works on similar tools, says the Microsoft software has the potential to improve patient care, providing it really does make scans easier to navigate. "As medical imaging has advanced, so many images are produced that there is a kind of information overload," he explains. "The workload has grown a lot."

Suzuki says Microsoft's approach is a good one, but that medical professionals might be more receptive to the design if it indexed signs of disease, not just organs. His own research group has developed software capable of recognizing potentially cancerous lung nodules; in trials, it made half as many mistakes as a human expert.

Criminisi sticks by the notion of using organs as a kind of navigation system but says that disease-spotting capability is also under development. He says, "We are working to train it to detect differences between different grades of glioma tumor"—a type of brain tumor.

The Microsoft group also intends the tool to be used at large scales. It could automatically index a collection of 3-D scans or other images, making possible new ways of tracking medical records, says Criminisi. Today, records are kept as text that describes scans and other information. A search tool that finds the word "heart", for example, would not know if that meant it appeared in a scan or was mentioned in another context. If a hospital's computer system indexed new scans, the Microsoft software could automatically record what was imaged in a person's records and when.

Read More

Scientists grow sperm out of skin tissue

Scientists grow sperm out of skin tissue

  12:48:00 PM    Science Lover

---

Infertile men have been given hope of conceiving children after scientists successfully grew sperm out of skin cells.

The breakthrough came when they took tissue from mice testicles and kept it alive for several weeks.

Breakthrough: Researchers have grown sperm from
tissue that was capable of fertilising an egg, meaning infertile
men could soon be able to fulfil their dreams of fatherhood

Researchers were able to grow sperm cells from this and inject them into female eggs, which produced babies.

The study gives hope to cancer patients who have been made infertile by chemotherapy.

It may allow men to freeze tissue from their testicles for scientists to grow healthy sperm from years later.

Leading fertility expert Dr Allan Pacey said: “It could help discover new drugs or treatments to stimulate infertile men to produce more or better sperm.

“For men who don’t have sperm to bank, to be able to freeze some testicular tissue and years later have sperm grown in the lab could allow them to have children that were genetically theirs.”

The study, carried out by Takehiko Ogawa at Yokohama University in Japan, created healthy baby mice, which later had babies themselves.

Separate research by Chinese scientists have created gay mice in a lab by reducing their serotonin. When they injected the brain chemical back into their brains, the males began chasing females again within 35 minutes.

Read More

Seeing in Stereo: Engineers Invent Lens for 3-D Microscope

Seeing in Stereo: Engineers Invent Lens for 3-D Microscope

  1:44:00 AM    Science Lover

---

Engineers at Ohio State University have invented a lens that enables microscopic objects to be seen from nine different angles at once to create a 3-D image.

A lens invented at Ohio State University 
enables microscopes to capture 3-D images 
of tiny objects. (Credit: Photo by Kevin 
Fitzsimons, courtesy of Ohio State University.)

Other 3-D microscopes use multiple lenses or cameras that move around an object; the new lens is the first single, stationary lens to create microscopic 3-D images by itself.

Allen Yi, associate professor of integrated systems engineering at Ohio State, and postdoctoral researcher Lei Li described the lens in a recent issue of the Journal of the Optical Society of America A.

Yi called the lens a proof of concept for manufacturers of microelectronics and medical devices, who currently use very complex machinery to view the tiny components that they assemble.

Though the engineers milled their prototype thermoplastic lens on a precision cutting machine, the same lens could be manufactured less expensively through traditional molding techniques, Yi said.

"Ultimately, we hope to help manufacturers reduce the number and sizes of equipment they need to miniaturize products," he added.

The prototype lens, which is about the size of a fingernail, looks at first glance like a gem cut for a ring, with a flat top surrounded by eight facets. But while gemstones are cut for symmetry, this lens is not symmetric. The sizes and angles of the facets vary in minute ways that are hard to see with the naked eye.

"No matter which direction you look at this lens, you see a different shape," Yi explained. Such a lens is called a "freeform lens," a type of freeform optics.

Freeform optics have been in use for more than a decade. But Lei Li was able to write a computer program to design a freeform lens capable of imaging microscopic objects.

Then Yi and Li used a commercially available milling tool with a diamond blade to cut the shape from a piece of the common thermoplastic material polymethyl methacrylate, a transparent plastic that is sometimes called acrylic glass. The machine shaved bits of plastic from the lens in increments of 10 nanometers, or 10 billionths of a meter -- a distance about 5,000 times smaller than the diameter of a human hair.

The final lens resembled a rhinestone, with a faceted top and a wide, flat bottom. They installed the lens on a microscope with a camera looking down through the faceted side, and centered tiny objects beneath the flat side.

Each facet captured an image of the objects from a different angle, which can be combined on a computer into a 3-D image.

The engineers successfully recorded 3-D images of the tip of a ballpoint pen -- which has a diameter of about 1 millimeter -- and a mini drill bit with a diameter of 0.2 millimeters.

"Using our lens is basically like putting several microscopes into one microscope," said Li. "For us, the most attractive part of this project is we will be able to see the real shape of micro-samples instead of just a two-dimensional projection."

In the future, Yi would like to develop the technology for manufacturers. He pointed to the medical testing industry, which is working to shrink devices that analyze fluid samples. Cutting tiny reservoirs and channels in plastic requires a clear view, and the depths must be carved with precision.

Computer-controlled machines -- rather than humans -- do the carving, and Yi says that the new lens can be placed in front of equipment that is already in use. It can also simplify the design of future machine vision equipment, since multiple lenses or moving cameras would no longer be necessary.

Other devices could use the tiny lens, and he and Li have since produced a grid-shaped array of lenses made to fit an optical sensor. Another dome-shaped lens is actually made of more than 1,000 tiny lenses, similar in appearance to an insect's eye.

This research was sponsored by the National Science Foundation. Moore Nanotechnology Systems in Keene, NH, provided the ultraprecision milling machine.

Read More

The technology that enables a computer to print off a full-working bicycle

The technology that enables a computer to print off a full-working bicycle

  9:58:00 AM    Science Lover

---

This bicycle is the first in the world to be created simply by printing it out on a computer, using groundbreaking new technology.

The fully-working cycle, which is made of nylon, is the result of an extraordinary project and is as strong as steel and aluminium but weighs 65 per cent less.

Scientists in Bristol designed the bike on a computer and sent it to a printer, which placed layers of melted nylon powder on top of each other to build-up the machine.

Let's ride: The fully-working cycle, which is made of nylon, is the result of an extraordinary project and is as strong as steel and aluminium but weighs 65 per cent less.

On the move: Scientists designed the bike on a computer and sent it to a printer, which placed layers of melted nylon powder on top of each other to build-up the machine

Individual components such as gears, pedals and wheels are usually made in different factories and assembled into a finished bike but the Airbike is a single, complete part.

The wheels, bearings and axle are incorporated into the 'growing' process, known as Additive Layer Manufacturing.

The Airbike can be built to the rider's own specification so requires no adjustment. It also requires no conventional maintenance or assembly.

It is made by the European Aeronautic Defence and Space group in Filton, near Bristol, The 3D printing method allows products to be made from a fine powder of nylon, carbon-reinforced plastics or metals such as titanium, stainless steel or aluminium.

They are drawn using computer-aided design and then sent to a printer, which is filled with the powdered material.

A computer splits the 3D design into many 2D layers and a laser beam is used to melt the powder material into the first of the layers.

This is then covered by a new layer of powder and the process is repeated with the next 'slice'.

The manufacturing process uses about one-tenth of the material required in traditional methods, reducing waste.

The technology is likely to be used in industrial applications such as aerospace, the motor industry and engineering.

Lead engineer Andy Hawkins said: 'The possibilities with ALM are huge - it's a game-changing technology.

'The beauty is that complex designs do not cost any extra to produce. The laser can draw any shape you like.

'Many unique design features have been incorporated into the Airbike, such as saddle cushioning or the integrated bearings encased within the hubs.'

Robin Southwell, chief executive of EADS UK, said: 'The Airbike is a fantastic example of British innovation at its very best.

'The team at EADS in Bristol includes world-class engineers who continue to push boundaries by working at the forefront of technology.'

Read More

Salt Grain-Sized Cameras Can Travel Inside Body

Salt Grain-Sized Cameras Can Travel Inside Body

  11:57:00 PM    Science Lover

---

Cameras have shrunk over time, but they've never been this small. 
* German engineers have created the smallest microcameras of their kind.
* The new inexpensive disposable cameras can be produced 25,000 at a time.
* The microcamera's applications include medical and automotive imaging.

A new microcamera developed by German 
researchers measures a mere 1 millimeter on each side.

A new camera is as small as a coarse grain of salt -- the tiniest of its kind. This microcamera could go far: traveling deep into the human body to reveal hidden nooks and crannies. And it could be used in cars to keep drivers safe.


"I have it here on the desk," said Michael Töpper, project manager at the Fraunhofer Institute for Reliability and Microintegration in Berlin, the large German R&D facility that worked on the device. "If you look at the camera, it's hard to believe that this is working."


Fraunhofer developed the camera with the specialized image sensor company Awaiba, which sought to improve miniaturized cameras for medical applications. Current microcameras require individual, manual manufacturing techniques that have kept costs high. Töpper and his colleagues developed a method to assemble the cameras on a single wafer using specialized polymers to bond the parts.


"The last step is then dicing the image sensor into individual camera chips," he said.


Each of the three sides of the camera measures a mere 1 millimeter. One wafer can be used to assemble 25,000 lenses on 25,000 cameras. The resulting resolution for each of the miniature cameras is in the range of 25,000 pixels. While that's not high enough for a professional photographer, it is high for medical applications, Töpper said.


More efficient manufacturing means lower costs, and the microcameras themselves are disposable. Töpper points to a process for sterilizing reusable endoscopic cameras, saying that usually involves lots of chemicals. Although the new microcameras are not recyclable, he says that they are primarily made from silicon and glass. "There are no hazardous materials."


In medicine, gastroenterologists regularly use small cameras to check patients. Colon cancer is the second leading cause of cancer death, resulting in 150,000 cases every year, according to Dr. Gregory Cooper, a Case Western Reserve University professor of medicine and oncology, and gastroenterologist at University Hospitals Case Medical Center.


"Most colon cancers are thought to be preventable if the patient has a colonoscopy," he said.


Screening for polyps and colorectal cancer can involve a fairly invasive double-balloon endoscope requiring sedation, or a large swallowable "pill cam" that sometimes moves through a 25-foot small bowel too fast to capture all the information.


Dr. Cooper said he thinks the Fraunhofer microcamera technology looks interesting, although he notes that a scope used with the disposable camera would still need sterilization.


"If it can get around some of the current limitations of endoscopy, i.e. the sedation and the need to sterilize things, the limited visualization of the small bowel -- I think it has promise," he said.


At the moment Awaiba is testing the devices, and plans to put the microcameras into production within the next two years, Töpper said. Beyond medicine, the cameras could serve a useful purpose in the automotive industry. Installing them in cars might make camera-assisted parking more ubiquitous, and they could also help monitor drivers who risk falling asleep at the wheel.


"If you think about very, very small cameras, you will find dozens of applications," Töpper said. "Just think about the camera in the phone: 10 years ago everybody was laughing. 'Who needs a camera in a phone?'"

Read More

Miniature Lasers Could Help Launch New Age of the Internet

Miniature Lasers Could Help Launch New Age of the Internet

  5:49:00 PM    Science Lover

---

A new laser device created at the University of Central Florida could make high-speed computing faster and more reliable, opening the door to a new age of the Internet.

Sabine Freisem, a senior research scientist who 
has been collaborating with Deppe for the past eight 
years, works on lasers in their UCF lab. (Credit: UCF)

Professor Dennis Deppe's miniature laser diode emits more intense light than those currently used. The light emits at a single wavelength, making it ideal for use in compact disc players, laser pointers and optical mice for computers, in addition to high-speed data transmission.

Until now, the biggest challenge has been the failure rate of these tiny devices. They don't work very well when they face huge workloads; the stress makes them crack.

The smaller size and elimination of non-semiconductor materials means the new devices could potentially be used in heavy data transmission, which is critical in developing the next generation of the Internet. By incorporating laser diodes into cables in the future, massive amounts of data could be moved across great distances almost instantaneously. By using the tiny lasers in optical clocks, the precision of GPS and high-speed wireless data communications also would increase.

"The new laser diodes represent a sharp departure from past commercial devices in how they are made," Deppe said from his lab inside the College of Optics and Photonics. "The new devices show almost no change in operation under stress conditions that cause commercial devices to rapidly fail."

"At the speed at which the industry is moving, I wouldn't be surprised if in four to five years, when you go to Best Buy to buy cables for all your electronics, you'll be selecting cables with laser diodes embedded in them," he added.

Deppe and Sabine Freisem, a senior research scientist who has been collaborating with Deppe for the past eight years, presented their findings in January at the SPIE (formerly The International Society for Optical Engineering) Photonics West conference in San Francisco.

Deppe has spent 21 years researching semiconductor lasers, and he is considered an international expert in the area. sdPhotonics is working on the commercialization of many of his creations and has several ongoing contracts.

"This is definitely a milestone," Freisem said. "The implications for the future are huge."

But there is still one challenge that the team is working to resolve. The voltage necessary to make the laser diodes work more efficiently must be optimized

Deppe said once that problem is resolved, the uses for the laser diodes will multiply. They could be used in lasers in space to remove unwanted hair.

"We usually have no idea how often we use this technology in our everyday life already," Deppe said. "Most of us just don't think about it. With further development, it will only become more commonplace."

Read More

Hackers tackle secure ID tokens

Hackers tackle secure ID tokens

  9:02:00 AM    Science Lover

---

Hackers have stolen data about the security tokens used by millions of people to protect access to bank accounts and corporate networks.

The SecurID tokens are widely used to grant access to sensitive information

RSA Security told customers about the "extremely sophisticated cyber attack" in an open letter posted online.

The company is providing "immediate remediation" advice to customers to limit the impact of the theft

It also recommended customers take steps, such as hardening password policies, to help protect themselves.

Proof positive

In the open letter, written by RSA boss Art Coviello, the company said that the data stolen would not help a "direct" attack on the the SecurID tokens.

It did not disclose exactly what had been purloined and only said that the information "specifically related to RSA's SecurID two-factor authentication products".

RSA's SecurID tokens are used by millions of people alongside passwords to beef up security.

As its name suggests, two-factor authentication involves improving security using two methods of identifying a user. The first factor is usually the traditional login ID and password combination.

The second factor can be a SecurID token that is paired with back-end software that generates a new six digit number every minute.

A token paired with this software generates the same numbers so only the holder will be able to type in the right digits and get access.

RSA said the information stolen could reduce the effectiveness of this two-factor authentication system if a company came under a broader attack by malicious hackers.

This could potentially put a lot of people at risk as RSA claims to have millions of people using its security technology to secure online accounts and access to corporate systems.

RSA recommended that firms monitor social network sites to spot if hackers were trying to capitalise on what they now know about RSA's systems.

This could be because hackers have got information about who has which token and might try to exploit that to trick employees into giving them access.

RSA also recommended reminding users about the dangers of responding to suspicious e-mails, to limit who can access critical infrastructure systems and to reinforce all policies surrounding SecurID token use.

There could be "tremendous repercussions" if criminals piggy-backed on what they know to stealthily get at corporate and other critical systems, said Richard Stiennon, chief research analyst at security firm IT-Harvest.

"You'd never have a sign that you've been breached," he said.

Read More

Masked Fears: Are Fears That Are Seemingly Overcome Only Hidden?

Masked Fears: Are Fears That Are Seemingly Overcome Only Hidden?

  8:34:00 AM    Science Lover

---

Fear is a natural part of our emotional life and acts as a necessary protection mechanism. However, fears sometimes grow beyond proportions and become difficult to shed. Scientists from Freiburg, Basel and Bordeaux have used computer simulations to understand the processes within the brain during the formation and extinction of fears.

One group of nerve cells in the brain controls the fear 
behaviour (right). This can be suppressed by a second 
group of nerve cells (left) -- but the fear is only masked, 
and has not disappeared completely. (Credit: Carlos 
Toledo/Bernstein Center Freiburg)

In the current issue of the scientific journal PLoS Computational Biology, Ioannis Vlachos from the Bernstein Center Freiburg and colleagues propose for the first time an explanation for how fears that were seemingly overcome are in reality only hidden.

The reason for the persistency of fears is that, literally, their roots run deep: Far below the cerebral cortex lies the "amygdala," which plays a crucial role in fear processes. Fear is commonly investigated in mice by exposing them simultaneously to a neutral stimulus -- a certain sound, for example -- and an unpleasant one. This leads to the animals being frightened of the sound as well. Context plays an important role in this case: If the scaring sound is played repeatedly in a new context without anything bad happening, the mice shed their fear again. It returns immediately, however, if the sound is presented in the original, or even a completely novel context. Had the mice not unlearned to be frightened after all?

The fact that fears can be "masked" has been known for some time. Recently, two co-authors of the present study discovered that two groups of nerve cells within the amygdala are involved in this process. By creating a model of the amygdala's neuronal network, Ioannis Vlachos and colleagues were now able to find an explanation for how such a masking of fears is implemented in the brain: One group of cells is responsible for the fear response, the second for its suppression. Activity of the latter inhibits the former and, thus, prevents fear signals to be transmitted to other parts of the brain. Nevertheless, the change in their connections that resulted in an increased activity in the fear-coding neurons in the first place, is still present. As soon as the masking by the fear-suppressing neurons disappears, for example by changing the context, these connections come into action again -- the fear returns.

According to the scientists, these insights can be transferred to us humans, helping to treat fears more successfully in the future.

Read More

Quantum Pen for Single Atoms Is a Big Step Toward Large-Scale Quantum Computing

Quantum Pen for Single Atoms Is a Big Step Toward Large-Scale Quantum Computing

  9:38:00 AM    Science Lover

---

Physicists at the Max Planck Institute of Quantum Optics succeeded in manipulating atoms individually in a lattice of light and in arranging them in arbitrary patterns. These results are an important step towards large scale quantum computing and for the simulation of condensed matter systems.

With the help of a laser beam, the scientists could address single atoms in the lattice of light and change their spin state. In this way they succeeded in having total control over the single atoms and in "writing" arbitrary two-dimensional patterns. (Credit: Image courtesy of Max Planck Institute of Quantum Optics)

Physicists around the world are searching for the best way to realize a quantum computer. Now scientists of the team around Stefan Kuhr and Immanuel Bloch at the Max Planck Institute of Quantum Optics (Garching/Munich) took a decisive step in this direction. They can now address and change the spin of single atoms with laser light and arrange them in arbitrary patterns. In this way, the physicists strung the atoms along a line and could directly observe their tunneling dynamics in a “racing duel” of the atoms. A register of hundreds of addressable quantum particles could serve for storing and processing of quantum information in a quantum computer.

In the present experiment, the scientists loaded laser-cooled rubidium atoms into an artificial crystal of light. These so-called optical lattices are generated by superimposing several laser beams. The atoms are kept in the lattice of light in a way similar to marbles being contained in the hollows of an egg carton.

A few months ago, the team of Stefan Kuhr and Immanuel Bloch showed that each site of the optical lattice can be filled with exactly one atom. With the help of a microscope, the scientists visualized the array atom by atom and thereby verified the shell-like structure of this “Mott insulator.” Now the scientists succeeded in individually addressing the atoms in the lattice and in changing their respective energy state. Using the microscope, they focused a laser beam down to a diameter of about 600 nanometers, which is just above the lattice spacing, and directed it at individual atoms with high precision.

The laser beam slightly deforms the electron shell of the addressed (targeted) atom and thereby changes the energy difference between its two spin states. Atoms with a spin – i.e. an intrinsic angular momentum – behave like little magnetic needles that can align in two opposite directions. If the atoms are irradiated with microwaves that are in resonance with the modified spin transition, only the addressed atoms absorb a microwave photon, which causes their spin to flip. All other atoms in the lattice remain unaffected by the microwave field.

The scientists demonstrated the high fidelity of this addressing scheme in a series of experiments. For this purpose, the spins of all atoms along a line were flipped one after the other, by moving the addressing laser from lattice site to lattice site. After removing all atoms with a flipped spin from the trap, the addressed atoms are visible as holes, which can easily be counted. In this way, the physicists deduced that the addressing worked in 95% of the cases. Atoms at the neighboring sites are not influenced by the addressing laser. The method provides the possibility to generate arbitrary distributions of atoms in the lattice.

Starting from an arrangement of 16 atoms that were strung together on neighboring lattice sites like a necklace of beads, the scientists studied what happens when the height of the lattice is ramped down so far that the particles are allowed to “tunnel” according to the rules of quantum mechanics. They move from one lattice site to the other, even if their energy is not sufficient to cross the barrier between the lattice wells. “As soon as the height of the lattice has reached the point where tunneling is possible, the particles start running as if they took part in a horse-race”, doctoral candidate Christof Weitenberg describes. “By taking snapshots of the atoms in the lattice at different times after the "starting signal", we could directly observe the quantum mechanical tunneling-effect of single massive particles in an optical lattice for the first time.”

The new addressing technique allows many interesting studies of the dynamics of collective quantum states, as they appear in solid state systems. It also opens new perspectives in quantum information processing. “A Mott isolator with exactly one atom per lattice site acts as a natural quantum register with a few hundred quantum bits, the ideal starting point for scalable quantum information processing,” as Stefan Kuhr explains. “We have shown that we can individually address single atoms. In order for the atom to suit as a quantum bit, we need to generate coherent superpositions of its two spin states. A further step is to realize elementary logical operations between two selected atoms in the lattice, so-called quantum gates.”

Read More