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Combining Light and Sound For Accurate, Painless 3-D Mammograms

Breast cancer screening today requires exposure to X-ray radiation. The X-ray images are difficult to interpret, causing anxiety-inducing false alarms and extensive follow-up tests that include biopsies. Besides, getting a mammogram is quite literally a pain, requiring an uncomfortable compression of the breast tissue.

Startup OptoSonics in Oriental, N.C. aims to make breast imaging more accurate, quick, painless, and radiation-free. The company’s technology relies on the photoacoustic effect—the generation of sound from light absorption—to create high-resolution 3-D images of the network of blood vessels inside the breast. “The idea is that because tumors induce the creation of additional blood vessels, you’d see a brighter spot and individual vessels feeding into the mass,” says Robert Kruger, the company’s president and co-founder. Kruger and his colleagues presented details of the technique at the Acoustical Society of America meeting last week.

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European Court Grants the Right to Be Forgotten

Mario Costeja Gonzalez's Google search results will change, thanks to a ruling today by the Court of Justice of the European Union, in Luxembourg. Costeja sought to force Google to stop linking to a newspaper announcement of a government auction of seized property of his. But even if he had not won his case Costeja's name would already return an avalanche of results related to a controversial battle in Europe over the so-called right to be forgotten. Around 200 court cases in Spain are pending this ruling, and more are sure to emerge here and across the European Union, where the ruling applies.

Costeja's battle dates to 2009, when the newspaper La Vanguardia digitized its archive, unintentionally reviving a chapter of Costeja's life he thought was resolved. The archive included a 19 January 1998 official announcement of government-seized properties on auction to settle Social Security debts, and a related March 1998 announcement.

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Aero-X Hoverbike To Go on Sale in 2017

When Aerofex showed off its "hoverbike" almost two years ago, the California firm received a flood of emails from people asking when they could buy one of their own. Now Aerofex has unveiled plans to begin selling a commercial model in 2017 for about US $85 000—but anyone eager for a head start on living the "Star Wars" dream can put down a preorder deposit of $5000 toward the final price.

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New Gadget Gives Consumers At-Home Lab Tests

Do you want to know your current level of testosterone? Are you curious about the amount of vitamin D in your blood? Typically your doctor would send a sample of your bodily fluids to a lab to find out such information, but soon consumers willing to plunk down their money will have DIY lab tests via a new gadget called Cue.

Customers can pre-order the device beginning today, with shipping expected in spring 2015. At launch, Cue will be able to perform five different tests, but its makers say this is just the beginning. "The large majority of tests you do in the lab today, we want to give you access to in your own home," says Ayub Khattak, cofounder and CEO of the eponymous startup Cue.

Khattak sees his company as the next step forward for the quantified self movement, in which consumers are using various gizmos to count their steps, chart their blood pressure, monitor their sleep, and so on. But Cue goes beyond the easily collected metrics of health, and delves into biochemical markers.

For now, Cue offers the ability to test for testosterone, vitamin D, the flu virus, luteinizing hormone, which indicates a woman's fertility, and C-reactive protein, which serves as a marker of inflammation. That may seem like a rather hodgepodge selection, but Cue cofounder Clint Sever claims these are the most common tests run by labs, and they will therefore be of the most use to the public.

For each test, the device uses a different customized cartridge, which contains microfluidic channels and the necessary reagents. When a cartridge is inserted, Cue prompts the user to collect a sample with the included sample wand. The testosterone test requires saliva, the flu test needs a nasal swab, and the others require a drop of blood. It remains to be seen whether consumers will be willing to bleed themselves in their quests for optimum health. Khattak believes they will, and says that the use of a blood sample will give people faith in the test's validity. "If you want a real answer when you go to the doctor, that's where you get the answer from," he says.

Once the sample wand is inserted into the cartridge, Cue takes over. The reagents combine with the sample inside the cartridge, and a sensor looks for the target molecule (such as testosterone or vitamin D) and detects its quantity. Cue then transmits the information via Bluetooth to the user's smartphone (iPhone or Android). The smartphone app lets the user track results over time, and also offers suggestions for the user. If a man is trying to boost his testosterone, Sever says, Cue might recommend certain foods or exercises.

Despite the fact that one of the Cue cartridges detects the presence of the flu virus, the company's founders explain that it can't be considered a diagnostic device. At the moment, it's just an "investigational device" that consumers can experiment with, but the company is pursuing FDA approval. As for that flu test, Sever says the device isn't meant to replace a doctor's visit. "It just gives you more information so you can have an informed conversation with your doctor," he says. "It's like taking your temperature with a thermometer."

We've seen some remarkable examples lately of serious science packed into small consumer-electronics packages. Just a few weeks ago, we blogged about a hand-held spectrometer that people can use to examine the molecular content of their food. The engineering in these devices is undoubtedly impressive, but we're still waiting to see if these catch on as products. Cue might have a tough time because it requires users to keep buying single-use cartridges. It also seems a bit unlikely that users will be as dedicated to their Cues as the people are in the company's launch video, which shows, for example, a surfer on a beach checking his inflammation levels before catching a gnarly wave.

Zapping Sleepers' Brains Causes Lucid Dreaming

Lucid dreams offer us the heady chance to shape our own fates in a fantasy world. In these dreams, sleepers realize they're dreaming and can sometimes take over their dreams' plots, allowing them to turn the tables on their enemies, soar into the sky, or embrace that special someone. Now, researchers in Germany have demonstrated that they can trigger lucid dreams by zapping sleeping people's brains with electricity.   

The researchers used a non-invasive neural stimulation method called transcranial alternating current stimulation (tACS) to send low-intensity electricity through the frontal and temporal lobes of 27 sleepers' brains. These portions of the cerebral cortex are associated with higher order cognitive functions, the researchers write, such as self-reflective awareness, abstract thinking, volition, and metacognition (thinking about thinking). Prior studies have shown that these brain regions are dormant during typical REM sleep, when dreams occur, yet are active during lucid dreams.

The tACS stimulation doesn't cause any noise or sensation, so it could be applied to the sleepers without waking them up. The researchers waited until their monitors showed that the subjects were in REM sleep, turned on the current, then woke up the sleepers and asked about the dreams they were having. The test subjects, none of who had experience with lucid dreaming, rated their dreams on factors like insight into the fact that they were dreaming, control of the dream plot, and dissociation, as if they were watching the dream from a third-person perspective.

Not every jolt of electricity produced a lucid dream report. Crucially, the researchers discovered that the effect depended on the frequency of the stimulation. Using the frequency of 40 Hz, researchers found that 77 percent of the reported dreams were rated lucid. At the frequency of 25 Hz, 58 percent of dreams met the criteria, while other frequencies (2, 6, 12, 70, and 100 Hz) produced a much smaller effect or no effect at all. This makes sense, the researchers say, because prior studies that have recorded the activity of the fronto-temporal lobes during lucid dreams have detected neural oscillations (patterns of neural activity) at the gamma frequency band, centered around 40 Hz. It seems stimulation at that frequency mimicked the brain mechanism that can naturally cause lucid dreams. 

But enough with the science, let's hear about those test subjects' dreams. Here are two reports from the paper:

Example of lucid dream report following 40-Hz stimulation: I was dreaming about lemon cake. It looked translucent, but then again, it didn’t. It was a bit like in an animated movie, like The Simpsons. And then I started falling and the scenery changed and I was talking to Matthias Schweighöfer (a German actor) and two foreign exchange students. And I was wondering about the actor and they told me “yes, you met him before,” so then I realized “oops, you are dreaming.” I mean, while I was dreaming! So strange!

Example of a non-lucid dream report (6 Hz): I am driving in my car, for a long time. Then I arrive at this place where I haven’t been before. And there are a lot of people there. I think maybe I know some of them but they are all in a bad mood so I go to a separate room, all by myself.

Neural stimulation is all the rage these days. A DIY community has sprung up around transcranial direct current stimulation (tDCS), a method similar to that used by the German researchers. Brain hackers are experimenting with using tDCS to tweak their cognition in various ways, such as improving memory and speeding up learning. In labs around the world, researchers are also investigating whether tDCS can be used to treat a wide variety of disorders, including depression, ADHD, and chronic pain. The age of brain zapping is upon us!

Computer-Aided Design Boosts Biochip Efficiency

When you come down to it, designing a lab-on-a-chip (LoC) strongly resembles managing a full-scale biomedical lab: Samples must be separated, technicians assigned, instruments scheduled, and apparatus cleaned. All of this has to be optimized to keep it running at peak efficiency, even when techs are out sick, machines go AWOL, and uncleaned glassware stacks up.

Michigan Technical University (MTU) researchers Chen Liao and Shiyan Hu are members of the relatively small group of researchers meeting the biochip-optimization challenge by developing computer-aided design (CAD) tools.  (A Google Scholar search for “CAD biochip” turns up 243 papers published since the beginning of 2013.) Specifically, the MTU engineers are building software to improve the physical layout of the "discrete-droplet" lab-on-a-chip. They reported their latest work in IEEE Transactions on Nanobioscience.

There are two basic kinds of biochips: Continuous flow chips have “permanently etched micropumps, microvalves, and microchannels.” And discrete-droplet chips have a two-dimensional array of chambers connected by channels, through which individual droplets are moved via electric-field-induced fluid flow, shunted from box to box by varying charges on electrodes that sandwich the chip. The discrete-droplet design is highly flexible: many droplets can be guided through the chip, like city buses traveling many routes through city streets.

Droplets can be guided into other droplets so their contents can react, then nudged toward yet another cell where a sensor stands ready to measure the results. If properly designed, a single discrete-droplet chip can conduct many different syntheses and analyses almost simultaneously by carefully shuffling droplets with different compositions around one another. Imagine doing a full blood-chemistry panel with a single drop on a single chip.

“In a very short time, you could test for many conditions,” Hu says. “This really would be an entire lab on a chip.”

But that “careful shuffling” is the rub: collision, contamination, variation, and dead-ends lurk at every corner, confounding simple routing and scheduling.  For example, droplets can never be in adjoining boxes. No droplet should occupy a box or run down a channel until the last vestiges of the previous droplet have dissipated. Reactions can run faster or slower with changes in temperature or humidity. Some measurements can take longer than others. And fabrication errors or later damage can put some boxes and channels out of commission entirely.

Liao and Hu map the chip’s surface, with its wells and channels, onto the x-y plane. Then they add a vertical axis of time. Every process then becomes a path through the space-time cube. Constraints mean that paths can never intersect. To prevent cross-contamination, a cocoon of open space and time must surround every path. The buffer around variable operations—such as DNA amplification or protein synthesis—increases still more to accommodate changes in timing. And some paths are blocked off completely to avoid blocked channels and damaged boxes.

Though earlier research had also constructed “contamination aware and defect tolerant” biochip algorithms, Liao and Hu say theirs is first to consider the effects of process-time variation.

To test the concept, they optimized designs, both with and without considering the effects of operation variation, and then ran a series of simulations to assess how each approach performed. The measuring stick was “routing yield,” the percentage of test runs that go successfully from beginning to end as process conditions varied. While the variation-tolerant process paths were slightly longer, the difference in success rates was striking. Designs that ignored process-time variation succeeded 15 to 62 percent of the time. Variation-aware processes scored 100 percent. Overall, an increase in process time of 3.5 percent produces a 51 percent jump in total throughput.

 “It has taken us four years to do the software, but to manufacture the [lab-on-a-chip] would be inexpensive,” Hu says. “The materials are very cheap, and the results are more accurate than a conventional lab’s.”

Electromagnetic Interference Disrupts Bird Navigation, Hints at Quantum Action

Repeated experiment failures have led to a most unexpected discovery about how songbird orientation may rely on the quantum phenomenon of electron spins. Researchers found out that very weak electromagnetic fields disrupt the magnetic compass used by European robins and other songbirds to navigate using the Earth's magnetic field.

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Smartphone App Could Flag Mood Swings in People With Bipolar Disorder

Psychiatrists know that they shouldn't just listen to what their patients say, but also how they say it. And now researchers at the University of Michigan have created a smartphone app that mimics that listening behavior. By analyzing the phone conversations of people with bipolar disorder, researchers say they've detected the speech patterns associated with manic and depressive episodes.

The small study included only six patients, and was intended as a proof of concept. Next the researchers want to develop an app that detects early signals of mood swings in people with bipolar disorder, allowing for prompt medical intervention. The researchers presented their paper this week at the IEEE International Conference on Acoustics, Speech, and Signal Processing.

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Norwegian Army Drives Tanks Using Oculus Rift VR Goggle

Virtual-reality goggles and camera systems are giving Norwegian soldiers the ability to "see through" their armored vehicles with a 360-degree view. That means drivers of trucks and tanks will be able see all around their vehicles on future battlefields without having to poke their heads out. It's something Odin the one-eyed Norse god could appreciate.

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“Sparse Arrays” Cut Costs for Terahertz Imaging

There are some stumbling block along the path to workable terahertz wave imaging. Building antenna arrays is one. Handling the information the arrays generate is another.

While some researchers have turned to metamaterials to cut down the bulk of terahertz antennas, a team at MIT is working on ways of doing more with less—fewer antennas and less computation—to smooth the road to low-cost mobile radars and sensitive detectors for explosives and firearms.

James Krieger, Yuval Kochman (now at the Hebrew University of Jerusalem), and Gregory Wornell report on strategies for faster, less expensive antenna design, signal-analysis, and error-correction in IEEE Transactions on Antennas and Propagation.

Terahertz radiation falls into the range between microwaves and visible light, at frequencies of 300 billion Hertz to 10 trillion Hz and wavelengths of 1000 to 30 micrometers. In a traditional phased array, antenna elements must be no farther than one-half a wavelength apart. A real-world application (such as an automotive collision-avoidance system that Krieger and his colleagues use as an example) might require an aperture of roughly 2 meters to properly resolve moving, vehicle-size objects. So a conventional array built to image signals at 100 GHz (with a 3 mm wavelength) would require on the order of 1000 antennas, while a 1 THz array would need about 10 000. Building such arrays is costly and complex in its own right. And the computational power needed to resolve the phased array’s signals into a 2-D image increases with the number of antennas—a demand that “quickly becomes impracticably large,” according the MIT group.

But one-antenna-every-half-wavelength resolution is only truly necessary if all objects of interest stand shoulder to shoulder at the same distance from the array. In the real world—a parking lot, say—targets are “sparse,” generally few and far between at any range or azimuth.

"Think about a range around you, like five feet," said  Wornell, the team leader. "There's actually not that much at five feet around you. Or at 10 feet. Different parts of the scene are occupied at those different ranges, but at any given range, it's pretty sparse. Roughly speaking, the theory goes like this: If, say, 10 percent of the scene at a given range is occupied with objects, then you need only 10 percent of the full array to still be able to achieve full resolution."

The trick is to come up with a method for deciding which half, quarter, fifth, or tenth of the possible antenna locations to populate. The MIT group breaks the array down into number of “periods,” each with the same number of lattice points one-half wavelength apart. (Periods with prime numbers of lattice points make for the easiest calculations.) The key is to select positions so that the range of distances between pairs of antennas covers the range of possible separations as evenly as possible. This is fairly easy to calculate directly with periods of 7 or 11 lattice points; it’s trickier for periods of 37, 47, or 57 nodes, but an iterative tactic (like the Markov Chain Monte Carlo method)  produces workable positioning patterns.

The periodic approach cuts down computing overhead by breaking the antennas down into “cosets” within each period. Coset data are collected, compared, and analyzed together, so the computational demand goes up with the number of antennas in a period, not with the total number of antennas.

In the 100 GHz parking lot simulation, a conventional phased array would require 987 individual antennas to attain the necessary 2-meter aperture. With the addition of algorithms for detecting and filtering out errors, the Wornell group’s multi-coset sparse array built usable images with as few as 105 antennas. (Remember, these are linear arrays producing a 2-D image. So a two-dimensional arrays to generate 3-D images would square the number of antennas needed—to about a million for a conventional array versus about 10 000 for a multi-coset sparse array.)

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