Monthly Archives: March 2009

Knowing when to fold

Folding paper into shapes such as a crane or a butterfly is challenging enough for most people. Now imagine trying to fold something that’s about a hundred times thinner than a human hair and then putting it to use as an electronic device.

A team of researchers led by George Barbastathis, associate professor of mechanical engineering, is developing the basic principles of “nano-origami,” a new technique that allows engineers to fold nanoscale materials into simple 3-D structures. The tiny folded materials could be used as motors and capacitors, potentially leading to better computer memory storage, faster microprocessors and new nanophotonic devices.

Traditional micro- and nano-fabrication techniques such as X-ray lithography and nano-imprinting work beautifully for two-dimensional structures, and are commonly used to build microprocessors and other micro-electrical-mechanical (MEMS) devices. However, they cannot create 3-D structures.

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Nanoscale Electronic Devices Could Soon Become A Reality

The tendency in electronic devices is all about getting smaller and smaller and smaller. It’s just the way these things need to be. However, they also have to be very efficient and we have nanotechnology and carbon nanotubes to make them like this. In order to develop smaller and more efficient electronics, scientists want to develop the next generation of devices based on carbon nanotubes using a technique called “chemical vapor deposition”, but it’s very hard to manipulate these structures and to bring them to a useful state.

A new vision is needed to complete the next-gen electronics and thanks to a breakthrough from scientists at the University of Nebraska-Lincoln, our future devices could be built from carbon nanotubes. The team of scientists led by professor Yongfeng Lu and postdoctoral researcher Yunshen Zhou, used a technique based on the so-called “optical near-field effects” and they managed to control the growth of carbon nanotubes. The researchers linked individually self-aligned carbon nanotubes with sharp-tipped electrodes, a process which is very different from previous techniques where the carbon nanotubes were manipulated after growth.

“With our method, there’s no requirement for expensive instrumentation and no requirement for tedious processes. It’s a one-step process. We call it ’self-aligning growth.’ The carbon nanotubes ‘know’ where to start growth. In previous efforts, they could only manipulate carbon nanotubes one piece at a time, so they had to align the carbon nanotubes one by one. For our approach using optical near-field effects, all locations with sharp tips can accommodate carbon nanotube growth. That means we can make multiple carbon nanotubes at a time and all of them will be self-aligned,” said professor Lu.

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Most powerful ever quantum chip undergoing tests

QUANTUM computing for the masses could come a step closer if tests prove successful on a prototype chip designed to process more quantum data than any previous device.

Quantum computers have the potential to be vastly more powerful than conventional machines because they exploit the rules of quantum mechanics to perform many calculations in parallel. They are difficult to build, however, because quantum information is easily destroyed. The most powerful machines to date can cope with only a handful of quantum bits, or qubits, making them little more capable than a hand-held calculator.

In contrast, the prototype chip built by D-Wave Systems in Burnaby, British Columbia, Canada, is designed to handle 128 qubits of information. The data is stored in 128 superconducting niobium loops as either a clockwise or an anticlockwise current, representing a 0 or a 1, or as a qubit with both currents at the same time in a quantum superposition. When the information needs to be processed, the individual qubits are manipulated by a magnetic field. To make the entire chip superconduct so that the currents can flow indefinitely without dissipating heat, it is cooled to 0.01 °C above absolute zero.

Because superconducting circuits are relatively large, they are easier to manufacture than other types of quantum devices, which manipulate single electrons or photons and so need to be much smaller. “It can be built using standard semiconductor approaches,” says Geordie Rose, chief technology officer of D-Wave. In addition, the method of computation, called adiabatic computing, does not use logic gates, further simplifying the design.

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The Doctor Kiosk

A computerized kiosk under development at Massachusetts General Hospital (MGH) can take a patient’s medical history, weight, pulse, blood pressure, and other vital signs, and even perform simple blood tests for glucose and cholesterol. Physicians hope that the device, slated to begin field testing in the United Kingdom in June, will one day bring relief to the overburdened healthcare system, and allow doctors to intervene earlier in chronic disease.

Doctors’ appointments in the United States often feel like more of an inconvenience than a help, both for patients, who can spend hours in waiting rooms, and doctors, who spend hours filling in charts and organizing patient information. Ronald Dixon, director of the Virtual Practice Project, imagines that his kiosk–a small, Windows-based desktop computer with just a few peripherals–could one day revolutionize doctors’ visits just as ATMs transformed banking. By removing the tellers from the interactions that could be easily automated, banks saved face-to-face contact for more complex transactions. Dixon, who’s also a primary-care physician at MGH, believes that the same could be done for doctors.

The kiosk consists of a tabletop computer and a number of peripherals–a blood-pressure cuff, a scale, a pulse oximeter to measure blood oxygen levels, and a peak-flow meter to determine whether someone’s airways are constricted–as well as a blood-testing device commonly used in emergency rooms that can measure cholesterol and glucose levels. (The current version requires a trained assistant to do the finger stick for blood collection, although future versions will be automated.)

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When Will We Cure Cancer?

Talk about wishful thinking. One might as well ask if there will be a war that will end all wars, or a pill that will make us all good looking. It is also a perfectly understandable question, given that half a million Americans will die this year of a disorder that is often discussed in terms that make it seem less like a disease than an implacable enemy. What tuberculosis was to the 19th century, cancer is to the 20th: an insidious, malevolent force that frightens people beyond all reason–far more than, say, diabetes or high blood pressure.

The problem is, the “cure” for cancer is not going to show up anytime soon–almost certainly not in the next decade. In fact, there may never be a single cure, one drug that will bring every cancer patient back to glowing good health, in part because every type of cancer, from brain to breast to bowel, is different.

Now for the good news: during the next 10 years, doctors will be given tools for detecting the earliest stages of many cancers–in some cases when they are only a few cells strong–and suppressing them before they have a chance to progress to malignancy. Beyond that, nobody can make predictions with any accuracy, but there is reason to hope that within the next 25 years new drugs will be able to ameliorate most if not all cancers and maybe even cure some of them. “We are in the midst of a complete and profound change in our development of cancer treatments,” says Richard Klausner, director of the National Cancer Institute. The main upshot of this change is the sheer number of drugs in development–so many that they threaten to swamp clinical researchers’ capacity to test them all.

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Found: the gene that could grow new teeth

A breakthrough by scientists could see dentures bite the dust.

Researchers have pinpointed the gene that governs the production of tooth enamel, raising the tantalising possibility of people one day growing extra teeth when needed.

At the very least, it could cut the need for painful fillings.

Experiments in mice have previously shown that the gene, a ‘transcription factor’ called Ctip2, is involved in the immune system and in the development of skin and nerves.

The latest research, from Oregon State University in the U.S., adds enamel production to the list.

The researchers made the link by studying mice genetically engineered to lack the gene.

The animals were born with rudimentary teeth which were ready to erupt but lacked a proper covering of enamel, the journal Proceedings of the National Academy of Sciences reports.

Researcher Dr Chrissa Kioussi said: ‘It’s not unusual for a gene to have multiple functions, but before this we didn’t know what regulated the production of tooth enamel.

‘This is the first transcription factor ever found to control the formation and maturation of ameloblasts, which are the cells that secrete enamel.’

The finding could be applied to human health and, if used in conjunction with fledgling stem cell technology, could one day allow people to grow replacement teeth when needed.

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FDA Allows Brain Implants for Obsessions

By manipulating the magnetization of a liquid solution, the researchers have for the first time coaxed magnetic and non-magnetic materials to form intricate nano-structures. The resulting structures can be “fixed,” meaning they can be permanently linked together. This raises the possibility of using these structures as basic building blocks for such diverse applications as advanced optics, cloaking devices, data storage and bioengineering.

Changing the levels of magnetization of the fluid controls how the particles are attracted to or repelled by each other. By appropriately tuning these interactions, the magnetic and non-magnetic particles form around each other much like a snowflake forms around a microscopic dust particle.

“We have demonstrated that subtle changes in the magnetization of a fluid can create an environment where a mixture of different particles will self-assemble into complex superstructures,” said Randall Erb, fourth-year graduate student. He performed these experiments in conjunction with another graduate student Hui Son, in the laboratory of Benjamin Yellen, assistant professor of mechanical engineering and materials science and lead member of the research team.

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Researchers develop ‘wireless’ activation of brain circuits

And it’s a unique collaboration between chemists and neuroscientists that led to the discovery of a remarkable new way to use light to activate brain circuits with nanoparticles.

Ben Strowbridge, an associate professor in the neurosciences department in the Case Western Reserve School of Medicine and Clemens Burda, an associate professor in chemistry, say it’s rare in science that people from very different fields get together and do something that is both useful and that no one had thought of before. But that is exactly what they’ve done.

By using semiconductor nanoparticles as tiny solar cells, the scientists can excite neurons in single cells or groups of cells with infrared light. This eliminates the need for the complex wiring by embedding the light-activated nanoparticles directly into the tissue. This method allows for a more controlled reaction and closely replicates the sophisticated focal patterns created by natural stimuli.

The electrodes used in previous nerve stimulations don’t accurately recreate spatial patterns created by the stimuli and also have potential damaging side effects.

“There are many different things you’d want to stimulate neurons for-injury, severed or damaged nerve to restore function- and right now you have to put a wire in there, and then connect that to some control system. It is both very invasive and a difficult thing to do,” says Strowbridge.

IIn principle, the researchers should be able to implant these nanoparticles next to the nerve, eliminating the requirement for wired connections. They can then use light to activate the particles.

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TR10: Paper Diagnostics

Diagnostic tools that are cheap to make, simple to use, and rugged enough for rural areas could save thousands of lives in poor parts of the world. To make such devices, Harvard University professor George Whitesides is coupling advanced microfluidics with one of humankind’s oldest technologies: paper. The result is a versatile, disposable test that can check a tiny amount of urine or blood for evidence of infectious diseases or chronic conditions.

The finished devices are squares of paper roughly the size of postage stamps. The edge of a square is dipped into a urine sample or pressed against a drop of blood, and the liquid moves through channels into testing wells. Depending on the chemicals present, different reactions occur in the wells, turning the paper blue, red, yellow, or green. A reference key is used to interpret the results.

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Canadians can read your mind

Be very careful what you think about Shania Twain. Not only is she a national hero in her homeland of Canada, she’s popular in America too, with the bestselling country album of all time to her name. Now, new technology developed by scientists in Toronto enables Canadians to detect how you feel about their favourite singer – without you even saying a word.

A team of researchers from the University of Toronto has developed a brain-scanning headset that can detect a person’s preferences, with an accuracy of 80%. The headset is fitted with fibre-optic cables that emit infrared light at around the same frequency as a typical TV remote control.

This harmless radiation is beamed into the prefrontal cortex, the area of the brain associated with decision-making. Here it is scattered by blood vessels, and the reflections are picked up by sensors on the headband. By measuring the amount of oxygen in the blood, researchers can decode brain activity and determine whether a person prefers Twain’s country pop to, say, the crooning of Céline Dion.

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