Thursday, September 6, 2012

Mapping neurological disease

Mapping neurological disease

Mapping neurological disease

Posted: 06 Sep 2012 03:32 AM PDT


Left: A functional magnetic resonance imaging (MRI) scan with cortical regions strongly correlated with motor activity highlighted in red. Right: A diffusion MRI scan with white-matter bundles passing through the corpus callosum shown in blue and red. (Credit: Marek Kubicki, Brigham and Womens' Hospital, Harvard Medical School)

MIT researchers have developed an algorithm that can analyze information from medical images to identify diseased areas of the brain and their connections with other regions.

Disorders such as schizophrenia can originate in certain regions of the brain and then spread out to affect connected areas. Identifying these regions of the brain, and how they affect the other areas they communicate with, would allow drug companies to develop better treatments and could ultimately help doctors make a diagnosis. But interpreting the vast amounts of data produced by brain scans to identify these connecting regions has so far proved impossible.

The algorithm, developed in the Computer Science and Artificial Intelligence Laboratory by Polina Golland, an associate professor of computer science, and graduate student Archana Venkataraman, extracts information from two different types of magnetic resonance imaging (MRI) scans.

Diffusion MRI looks at how water diffuses along the white-matter fibers in the brain, providing insight into how closely different areas are connected to one another. And functional MRI (fMRI), probes how different parts of the brain activate when they perform particular tasks, and so can reveal when two areas are active at the same time and are therefore connected.

These two scans alone can produce huge amounts of data on the network of connections in the brain, Golland says. "It's quite hard for a person looking at all of that data to integrate it into a model of what is going on, because we're not good at processing lots of numbers."

The algorithm first compares all the data from the brain scans of healthy people with those of patients with a particular disease, to identify differences in the connections between the two groups that indicate disruptions caused by the disorder. However, this step alone is not enough, since much of our understanding of what goes on in the brain concerns the individual regions themselves, rather than the connections between them, making it difficult to integrate this information with existing medical knowledge.

So the algorithm then analyzes this network of connections to create a map of the areas of the brain most affected by the disease. "It is based on the assumption that with any disease you get a small subset of regions that are affected, which then affect their neighbors through this connectivity change," Golland says. "So our methods extract from the data this set of regions that can explain the disruption of connectivity that we see."

It does this by hypothesizing, based on an overall map of the connections between each of the regions in the brain, what disruptions in signaling it would expect to see if a particular region were affected. In this way, when the algorithm detects any disruption in connectivity in a particular scan, it knows which regions must have been affected by the disease to create such an impact. "It basically finds the subset of regions that best explains the observed changes in connectivity between the normal control scan and the patient scan," Golland says.

When the team used the algorithm to compare the brain scans of patients with schizophrenia to those of healthy people, they were able to identify three regions of the brain — the right posterior cingulate and the right and left superior temporal gyri — that are most affected by the disease.

Better treatments

In the long term, this could help drug companies develop more effective treatments for the disease that specifically target these regions of the brain, Golland says. In the meantime, by revealing all the different parts of the brain that are affected by a particular disorder, it can help doctors to make sense of how the disease evolves, and why it produces certain symptoms.

Ultimately, the method could also be used to help doctors diagnose patients whose symptoms could represent a number of different disorders, Golland says. By analyzing the patient's brain scan to pinpoint which regions are affected, it could identify which disorder would create this particular disruption, she says.

In addition to schizophrenia, the researchers, who developed the algorithm alongside Marek Kubicki, associate director of the Psychiatry Neuroimaging Laboratory at Harvard Medical School, are also investigating the possibility of using the method to study Huntington's disease.

Gregory Brown, associate director of clinical neuroscience at the University of California at San Diego's Center for Functional MRI, who was not involved in developing the model, plans to use it to study the effects of HIV and drug addiction. "We will use the method to gain a clearer perspective on how HIV infection and methamphetamine dependence disrupts large-scale brain circuitry," he says.

The method is a critical step away from studying the brain as a collection of localized regions toward a more realistic systems perspective, he says. This should assist the study of disorders such as schizophrenia, neurocognitive impairment and dementia associated with AIDS, and multiple sclerosis, which are best characterized as diseases of brain systems, he says.

Tough super-stretchable gel is tougher than cartilage and heals itself

Posted: 06 Sep 2012 02:42 AM PDT


The researchers pinned both ends of the new gel in clamps and stretched it to 21 times its initial length before it broke (credit: Jeong-Yun Sun.)

A team of experts in mechanics, materials science, and tissue engineering at Harvard have created an extremely stretchy and tough gel that may pave the way to replacing damaged cartilage in human joints or spinal disks.

Called a hydrogel, because its main ingredient is water, the new material is a hybrid of two weak gels that combine to create something much stronger.

This new gel can stretch to 21 times its original length, but it is also exceptionally tough, self-healing, and biocompatible — a valuable collection of attributes that opens up new opportunities in medicine and tissue engineering.

It could also be used in soft robotics, optics, artificial muscle, as a tough protective covering for wounds, or "any other place where we need hydrogels of high stretchability and high toughness," the researchers suggest.

"Conventional hydrogels are very weak and brittle — imagine a spoon breaking through jelly," explains lead author Jeong-Yun Sun, a postdoctoral fellow at the Harvard School of Engineering and Applied Sciences (SEAS). "But because they are water-based and biocompatible, people would like to use them for some very challenging applications like artificial cartilage or spinal disks. For a gel to work in those settings, it has to be able to stretch and expand under compression and tension without breaking."

By themselves, polyacrylamide gels (a) and alginate gels (b) are brittle. The new hydrogel (c), however, has a more complex molecular structure that helps to dissipate stress across a wide area. The red circles represent calcium ions, and the blue triangles and green squares represent covalent crosslinks between chains. (Credit: Jeong-Yun Sun and Widusha R. K. Illeperuma.)

To create the tough new hydrogel, they combined two common polymers. The primary component is polyacrylamide, known for its use in soft contact lenses and as the electrophoresis gel that separates DNA fragments in biology labs; the second component is alginate, a seaweed extract that is frequently used to thicken food.

Separately, these gels are both quite weak — alginate, for instance, can stretch to only 1.2 times its length before it breaks. Combined in an 8:1 ratio, however, the two polymers form a complex network of crosslinked chains that reinforce one another. The chemical structure of this network allows the molecules to pull apart very slightly over a large area instead of allowing the gel to crack.

The researchers used a razor blade to cut a 2-cm notch across the gel. This damaged gel was still able to stretch to 17 times its initial length without breaking. (Credit: Jeong-Yun Sun.)

The alginate portion of the gel consists of polymer chains that form weak ionic bonds with one another, capturing calcium ions (added to the water) in the process. When the gel is stretched, some of these bonds between chains break — or "unzip," as the researchers put it — releasing the calcium. As a result, the gel expands slightly, but the polymer chains themselves remain intact. Meanwhile, the polyacrylamide chains form a grid-like structure that bonds covalently (very tightly) with the alginate chains.

So if the gel acquires a tiny crack as it stretches, the polyacrylamide grid helps to spread the pulling force over a large area, tugging on the alginate's ionic bonds and unzipping them here and there. The research team showed that even with a huge crack, a critically large hole, the hybrid gel can still stretch to 17 times its initial length.

Importantly, the new hydrogel is capable of maintaining its elasticity and toughness over multiple stretches. Provided the gel has some time to relax between stretches, the ionic bonds between the alginate and the calcium can "re-zip," and the researchers have shown that this process can be accelerated by raising the ambient temperature.

The group's combined expertise in mechanics, materials science, and bioengineering enabled the group to apply two concepts from mechanics — crack bridging and energy dissipation — to a new problem.

Sun and his coauthors were led by three faculty members: Zhigang Suo, Allen E. and Marilyn M. Puckett Professor of Mechanics and Materials at SEAS and a Kavli Scholar at the Kavli Institute for Bionano Science and Technology at Harvard; Joost J. Vlassak, Gordon McKay Professor of Materials Engineering and an Area Dean at SEAS; and David J. Mooney, Robert P. Pinkas Family Professor of Bioengineering at SEAS and a Core Faculty Member at the Wyss Institute for Biologically Inspired Engineering at Harvard.

"The unusually high stretchability and toughness of this gel, along with recovery, are exciting," says Suo. "Now that we've demonstrated that this is possible, we can use it as a model system for studying the mechanics of hydrogels further, and explore various applications. It's very promising."


Atlas Shrugged Part II

Posted: 05 Sep 2012 09:36 PM PDT

The global economy is on the brink of collapse. Unemployment has risen to 24%. Gas is now $42 per gallon. Brilliant creators, from artists to industrialists, continue to mysteriously disappear at the hands of the unknown.

Dagny Taggart, Vice President in Charge of Operations for Taggart Transcontinental, has discovered what may very well be the answer to a mounting energy crisis — found abandoned among the ruins of a once productive factory, a revolutionary motor that could seemingly power the World.

But, the motor is dead… there is no one left to decipher its secret … and, someone is watching.

It's a race against the clock to find the inventor before the motor of the World is stopped for good.

Who is John Galt?

Release details

Atlas Shrugged Movie on the Web

Researchers develop new, less expensive nanolithography technique

Posted: 05 Sep 2012 05:48 AM PDT

Ivanisevic cantilever image

This technique uses no electronic components to bring the cantilevers into contact with the substrate surface (credit: Kramer and Ivanisevic, North Carolina State University)

Researchers from North Carolina State University have developed a new nanolithography technique — a way of printing patterns at the nanoscale —.that is less expensive than other approaches and can be used to create technologies with biomedical applications.

This technique uses no electronic components to bring the cantilevers into contact with the substrate surface.

"Among other things, this type of lithography can be used to manufacture chips for use in biological sensors that can identify target molecules, such as proteins or genetic material associated with specific medical conditions," says Dr. Albena Ivanisevic, an associate professor of materials science and engineering at NC State and associate professor of the joint biomedical engineering program at NC State and the University of North Carolina at Chapel Hill.

The new technique relies on cantilevers, which are 150-micron long silicon strips. The cantilevers can be tipped with spheres made of polymer or with naturally occurring spores. The spheres and spores are coated with ink and dried. The spheres and spores are absorbent and will soak up water when exposed to increased humidity.

As a result, when the cantilevers are exposed to humidity in a chamber, the spheres and spores absorb water – making the tips of the cantilevers heavier and dragging them down into contact with any chosen surface.

Users can manipulate the size of the spheres and spores, which allows them to control the patterns created by the cantilevers. For example, at low humidity, a large sphere will absorb more water than a small sphere, and will therefore be dragged down into contact with the substrate surface. The small sphere won't be lowered into contact with the surface until it is exposed to higher humidity and absorbs more water.

Further, the differing characteristics of sphere polymers and spores mean that they absorb different amounts of water when exposed to the same humidity – giving users even more control of the nanolithography.

"This technique is less expensive than other device-driven lithography techniques used for microfabrication because the cantilevers do not rely on electronic components to bring the cantilevers into contact with the substrate surface," Ivanisevic says. "Next steps for this work include using this approach to fabricate lithographic patterns onto tissue for use in tissue regeneration efforts."

Transhuman week: exploring the frontiers of human enhancement

Posted: 05 Sep 2012 05:43 AM PDT

Wired U.K.'s Transhuman Week seeks to navigate transhumanist issues through a series of features, galleries and expert guest posts from September 3 to 7.

Transhumanism explores the application of technology and science to enhance human bodies and minds regardless of whether they are perceived to have any disabilities, and extending human life. It  may include low-level biohacking, physical augmentation, performance-enhancing drugs and even genetic modification.

The London 2012 Paralympic Games have drawn attention to the role that technology and science can play in overcoming human limitations.


Silicon chip enables mass-manufacture of quantum technologies

Posted: 05 Sep 2012 05:41 AM PDT

Multi-mode interference coupler and the manipulation of entanglement demonstrated in a Mach-Zehnder interferometer. a) SEM image of an multi-mode interference coupler. (b) Schematic diagram of a waveguide circuit with a voltage-controlled phase shifter. (c) Illustration of the cross-section of the single-mode waveguide. (Credit: University of Bristol)

Scientists from the University of Bristol's Centre for Quantum Photonics have developed a silicon chip that may pave the way to the mass-manufacture of miniature quantum chips, described in open-access articles.

The leap from using glass-based circuits to silicon-based circuits is significant because fabricating quantum circuits in silicon has the major advantage of being compatible with modern microelectronics.

Ultimately this technology could be integrated with conventional microelectronic circuits, and could one day allow the development of hybrid conventional/quantum microprocessors.

"Using silicon to manipulate light, we have made circuits over 1000 times smaller than current glass-based technologies," said Mark Thompson, Deputy Director of the Centre for Quantum Photonics in the University's Schools of Physics and Electrical & Electronic Engineering.

"It will be possible to mass-produce this kind of chip using standard microelectronic techniques, and the much smaller size means it can be incorporated in technology and devices that would not previously have been compatible with glass chips.

The Bristol-lead research team now believes that all the key components are in place to realize a fully functioning quantum processor — a powerful type of computer that uses quantum bits (qubits) rather than theconventional bits used in today's computers. This work was carried out with collaborators including Heriot-Watt University in Scotland and Delft University in the Netherlands.

Unlike conventional silicon chips that work by controlling electrical current, quantum circuits manipulate single particles of light (photons) to perform calculations.

These circuits exploit strange quantum mechanical effects such as superposition (the ability for a particle to be in two places at once) and entanglement (strong correlations between particles that would be nonsensical in our everyday world). The technology developed uses the same manufacturing techniques as conventional microelectronics, and could be economically scaled for mass-manufacture. These new circuits are compatible with existing optical fiber infrastructure and are ready to be deployed directly with the Internet.

Realizing the promise of RNA nanotechnology for new drug development

Posted: 05 Sep 2012 05:16 AM PDT


Self-assembled RNA nanoparticles as potential therapeutic agents. Transmission electron microscopy (TEM) images of RNA microsponges. (Credit: Lee et al., 2012)

The use of RNA in nanotechnology applications is highly promising for many applications, including the development of new therapeutic compounds, but keh technical challenges remain, presented in a an open-access review article in Nucleic Acid Therapeutics.

In "Uniqueness, Advantages, Challenges, Solutions, and Perspectives in Therapeutics Applying RNA Nanotechnology," Peixuan Guo and colleagues, University of Kentucky, Lexington, highlight the ability of RNA to self-assemble into nanoparticles with diverse structures.

The authors provide a detailed description of the main challenges faced by the RNA therapeutics industry, including the chemical and thermodynamic instability of the molecules, potential safety and side effect issues, difficulties in delivery and specific targeting, and low yield and high production costs in manufacturing.


A virus that kills cancer: the cure that’s waiting in the cold

Posted: 05 Sep 2012 05:09 AM PDT


Oncolytic viral therapy uses genetically-modified viruses to destroy cancer tumors (credit: NBCI)

Professor Magnus Essand has developed a virus that may kill cancer cells, The Telegraph reports.

Cheap to produce, the virus is exquisitely precise, with only mild, flu-like side-effects in humans. But Ad5[CgA-E1A-miR122]PTD is never going to be tested to see if it might also save humans, due to lack of funding.

Morality for robots?

Posted: 05 Sep 2012 04:57 AM PDT


In new book, NIU Northern Illinois University Professor David Gunkel examines ethical questions raised by 21st century computers, robots and artificial intelligence.

On the topic of computers, artificial intelligence and robots,  he says science fiction is fast becoming "science fact."

Fictional depictions of artificial intelligence have run the gamut from the loyal Robot in "Lost in Space" to the killer computer HAL in "2001: A Space Odyssey" and the endearing C-3PO and R2-D2 of "Star Wars" fame.

While those robotic personifications are still the stuff of fiction, the issues they raised have never been more relevant than today, says Gunkel, an NIU Presidential Teaching Professor in the Department of Communication.

In his new book, "The Machine Question: Critical Perspectives on AI, Robots, and Ethics," Gunkel ratchets up the debate over whether and to what extent intelligent and autonomous machines of our own making can be considered to have legitimate moral responsibilities and any legitimate claim to moral treatment.

"A lot of the innovation in thinking about machines and their moral consideration has been done in science fiction, and this book calls upon fiction to show us how we've confronted the problem," Gunkel says. "In fact, the first piece of writing to use the term 'robot' was a 1920s play called 'R.U.R.,' which included a meditation on our responsibilities to these machines."

Gunkel, who holds a Ph.D. in philosophy, notes that a cornerstone of modern ethical thought has been significantly challenged, most visibly by animal rights activists but also increasingly by those at the cutting edge of technology. "If we admit the animal should have moral consideration, we need to think seriously about the machine," Gunkel says. "It is really the next step in terms of looking at the non-human other."

Gunkle points out that real decision-making machines are now ensconced in business, personal lives and even national defense. Machines are trading stocks, deciding whether you're credit-worthy and conducting clandestine Drone missions overseas.

"Online interactions with machines provide an even more pervasive example," Gunkel adds. "It's getting more difficult to distinguish whether we're talking to a human or to a machine. In fact, the majority of activity on the Internet is  machine to machine traffic. Machines have taken over; it has happened."

Some machines even have the ability to innovate or become smarter, raising questions over who is responsible for their actions. "It could be viewed as if the programmer who writes the original program is like a parent who no longer is responsible for the machine's decisions and innovations," Gunkel says.

Some governments are beginning to address the ethical dilemmas. South Korea, for instance, created a code of ethics to prevent human abuse of robots — and vice versa. Meanwhile, Japan's Ministry of Economy, Trade and Industry is purportedly working on a code of behavior for robots, especially those employed in the elder-care industry.

Ethical dilemmas are even cropping up in sports, Gunkel says, noting recent questions surrounding human augmentation.

He points to the case of South African sprinter and double amputee Oscar Pistorius, nicknamed "blade runner" because he runs on two prosthetic legs made of carbon-fiber. In 2008, Pistorius was restricted from competing in the Beijing Olympics because there was concern that he had an unfair advantage. This decision was successfully challenged, and Pistorius competed in the 2012 London Games.

Similar concerns about the fairness of human augmentation can be seen in the recent crisis "concerning pharmacological prosthetics, or steroids, in professional baseball," Gunkel says. "This is, I would argue, one version of the machine question."

But Gunkel says he was inspired to write "The Machine Question" because engineers and scientists are increasingly bumping up against important ethical questions related to machines.

"Engineers are smart people but are not necessarily trained in ethics," Gunkel says. "In a way, this book aims to connect the dots across the disciplinary divide, to get the scientists and engineers talking to the humanists, who bring 2,500 years of ethical thinking to bear on these problems posed by new technology.

"The real danger," Gunkel adds, "is if we don't have these conversations."

In "The Machine Question," Gunkel frames the debate, which in recent years has ramped up in academia, where conferences, symposia and workshops carry provocative titles such as "AI, Ethics, and (Quasi) Human Rights."

He concludes in his new book that the moral community indeed has been far too restrictive. "Historically, we have excluded many entities from moral consideration and these exclusions have had devastating effects for others," Gunkel says. "Just as the animal has been successfully extended moral consideration in the second-half of the 20th century, I conclude that we will, in the 21st century, need to consider doing something similar for the intelligent machines and robots that are increasingly part of our world."

Blocking the sun: study looks at costs of 6 geoengineering schemes

Posted: 05 Sep 2012 04:50 AM PDT


(Credit: NASA)

As the planet warms and the world continues to emit greenhouse gases at a searing pace, some argue that geoengineering ideas are rapidly becoming attractive, if not downright necessary, IEEE Spectrum reports.

In other words, hack the planet.

One of the two main categories of geoengineering is solar radiation management, or SRM. (The other is the direct removal of carbon dioxide from the atmosphere.) The idea is to mimic what volcanos do naturally, by putting aerosol particles into the stratosphere on a massive scale. For example, when Mount Pinatubo erupted in 1991, the cloud that encircled the planet caused an overall cooling of about half a degree. An argument has been raging for years now about the wisdom of creating our own version of a volcanic eruption: Can it be done? Should it be done? What are the risks? What are the benefits? A few countries and research groups have tried to start demonstration projects; even these proof-of-concept exercises have garnered significant backlash from the scientific community as well as the public at large.

Most scientists would agree, though, that geoengineering ideas are at least worth looking into. And one of the primary questions is whether we can afford to do it. A new study published in the journal Environmental Research Letters has done a thorough cost analysis of the main techniques for SRM — importantly, this is not a cost-benefit analysis, where risks and benefits are included, but simply a look at the costs of putting enough aerosols into the atmosphere. What they found is either encouraging or terrifying, depending on one's feelings about geoengineering: it is, in the grand scheme of things, very, very cheap.

The authors, Justin McClellan, David Keith, and Jay Apt, found six main schemes for SRM:

1. Existing airplanes

Using aircraft to drop lots of aerosols into the stratosphere is the simplest method. Existing planes would require modification to fly high enough, which does increase the cost; still, putting one million metric tons of aerosols between 20 and 30 km into the air would require a mere $1 to $3 billion per year.

2. New airplanes

Those modifications required for existing aircraft suggest that simply designing new ones for this purpose might be the way to go. The cost analysis indicates a slightly cheaper overall price, probably below $2 billion per year to provide the same output.

3. Guns

This is, obviously, a radically different approach. Starting with a two-decade-old analysis of using a battleship-based 16″ Mark 7 naval gun to distribute aerosols, the study also looked into newer ideas including electromagnetic and hydrogen gas-based gun systems. Perhaps not surprisingly, delivering the required payload by firing guns into the sky does not turn out to be the cheapest way to go ($137 billion per year, using the original Mark 7 gun; $19 billion per year with a modernized version of the gun).

4. Rockets

Or more accurately, rocket-powered gliders. This sounds incredibly cool, but again, the costs go well beyond the stratosphere. Even using "off-the-shelf rocket engines" (I, for one, have never seen such a shelf) the cost to distribute enough aerosols would be a stunning $390 billion per year.

5. Airships

The authors note that airships — i.e., blimps — are attractive because of a large payload capacity and long endurance potential. Getting them up high enough and into strong wind shears will be a problem, though; costs are similar to that for aircraft, in the $2 billion per year range, with much of that going toward high-altitude R&D.

6. Pipes

The most far-fetched idea has arguably come closest to being implemented. Akin to "space elevator" schemes, this involves a 20-kilometer pipe running from the ground and suspended by helium balloons. Crazy, right? Well, one demonstration experiment planned in the United Kingdom was scrapped only after some patent conflict-of-interest issues were raised. In this analysis, the pipe method would cost a modest $4 to $10 billion per year.

The authors conclude, as others have in the past, that hacking the planet is "feasible from an engineering standpoint." They are quick to point out, though, the technical achievability and relative affordability "[do] not mean that SRM is a preferred strategy." There is still much work to be done on the risks of such large-scale science experiments, and critics often point out that blocking the sun's rays as a way to bring down temperatures does nothing to stop the rapid acidification of the oceans.

Still, the cost analysis and the continued international failure to act on climate change make geoengineering ever more intriguing. The authors point out that the estimated costs of unabated climate change range between $200 billion and $2 trillion per year by 2030 (and some estimates, like the Stern Review, lean even higher, toward 5 percent of global GDP per year). Cutting back on emissions is everyone's first choice for fighting back, but every year of inaction leads us closer to the geoengineering precipice.

Justin McClellan, David W Keith, Jay Apt, Cost analysis of stratospheric albedo modification delivery systems, Environmental Research Letters, 2012, DOI: 10.1088/1748-9326/7/3/034019 (open access)

Experts declare ‘cyber war’ on cancer’s ‘social networking’

Posted: 05 Sep 2012 04:26 AM PDT


Social bacteria: this colony of bacteria contains pioneer cells that pave the way for colony expansion in the same way that specialized cancer cells prepare for metastasis.(credit: Eshel Ben-Jacob/Tel Aviv University)

In the face of mounting evidence that cancer cells communicate, cooperate and even engage in collective decision-making, biophysicists and cancer researchers at Rice University, Tel Aviv University and Johns Hopkins University are suggesting a new strategy for outsmarting cancer through its own social intelligence.

"We need to get beyond the notion that cancer is a random collection of cells running amok —  these cells lead sophisticated social lives," said Herbert Levine, co-director of Rice's Center for Theoretical Biological Physics (CTBP) and co-author of the cover article in this week's Trends in Microbiology that pulls together dozens of recent discoveries about the social behavior of cancer cells.

"Cancer is a sophisticated enemy," said article co-author Eshel Ben-Jacob, a senior investigator at Tel Aviv University. "There's growing evidence that cancer cells use advanced communications to work together to enslave normal cells, create metastases, resist drugs and decoy the body's immune system."

Ben-Jacob, Levine and Donald Coffey, a noted cancer researcher at Johns Hopkins, suggest that cancer researchers act like modern generals and go after their enemy's command, control and communication capabilities.

"It's time to declare a cyber war on cancer," said Ben-Jacob, who, along with Coffey, spoke this week at a workshop titled "Failures in Clinical Treatment of Cancer" at Princeton University.

Conspiratorial cancer cells

Ben-Jacob said cancer cells have been shown to cooperate to elude chemotherapy drugs, much like bacteria that communicate and act as a team to resist attacks from antibiotics. He said some cancers appear to sense when chemotherapy drugs are present and sound an alarm that causes cells throughout a tumor to switch into a dormant state. Similar signals are later used to sound the "all clear" and reawaken cells inside the tumor.

"If we can break the communication code, we may be able to prevent the cells from going dormant or to reawaken them for a well-timed chemotherapeutic attack," Ben-Jacob said. "This is just one example. Our extensive studies of the social lives of bacteria suggest a number of others, including sending signals that trigger the cancer cells to turn upon themselves and kill one another."

The article cites numerous examples of similarities between the behavior of bacterial colonies and cancerous tumors.

"The parallels between the communal behaviors of bacteria and cancer cells suggest that bacteria can serve as a valuable model system for studying cancer," said Coffey, professor of urology, oncology, pathology and pharmacology and molecular sciences at the Johns Hopkins University School of Medicine. "We believe this approach could be particularly valuable for investigating intractable problems like metastasis, relapse and multiple drug resistance."

Levine, Rice's Karl F. Hasselmann Professor in Bioengineering, and fellow CTBP co-director José Onuchic were recruited to Houston last year, thanks in part to a grant from the Cancer Prevention and Research Institute of Texas (CPRIT) that was designed to spur new thinking about cancer and foster collaborations between CTBP scientists and cancer specialists in the Texas Medical Center.

"This opinion article reflects the multidisciplinary strategy of the CTBP — to communicate and work together with researchers across disciplines for solving the biomedical challenges of our time," said Onuchic, Rice's Harry C. and Olga K. Wiess Professor of Physics and Astronomy and professor of chemistry.

Ben-Jacob, the Maguy-Glass Chair in Physics of Complex Systems and professor of physics and astronomy at Tel Aviv University, worked previously with Levine and Onuchic on a number of groundbreaking studies about the underlying biophysics of bacterial social behavior. He joined Rice University this summer as senior investigator of the CTBP and adjunct professor of chemistry and cell biology.

Making stretchable electronics

Posted: 05 Sep 2012 03:42 AM PDT


Stretchable electronics (credit: MC10)

MC10, a startup, is getting ready to commercialize high-performance electronics that can stretch, allowing for innovations such as skin patches that monitor whether the wearer is sufficiently hydrated, or inflatable balloon catheters equipped with sensors that measure electrical misfiring caused by cardiac arrhythmias, Technology Review reports

To make both the hydration-­sensing patch and the catheter, gold electrodes and wires just a few hundred nanometers thick are deposited on silicon wafers by conventional means, then peeled off and applied to stretchable polymers.

The  technologies have advantages over other approaches to flexible electronics. For example, organic polymer electronics can only bend, not stretch, and they are slower than devices made of inorganic semiconductor materials or precious metals such as gold, so they can't provide precise real-time biological readings.

MC10 is working on patches that use sensors to detect heartbeat, respiration, motion, temperature, blood oxygenation, and combinations of these indicators.

MC10′s skin patches can wirelessly transmit information to a nearby smartphone. A phone with a near-field communication chip can be waved over the patch, or the patch can be paired with a thin-film battery made by a commercial supplier, allowing continuous data transmission.

Next up will be balloon catheters that a cardiologist could snake through the heart to detect areas of misfiring cardiac tissue. Some of the prototypes in preclinical testing have dense arrays of electrodes that allow high-resolution mapping and ablation of that tissue. Further off are other medical devices, including implantable materials that conform to brain tissue, sensing seizures and stopping them.

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