The past two decades have brought about some incredible – and very expensive – advances in prosthetic limb technology. A prosthetic leg can now contain microprocessors, gyroscopes, and hydraulics to give the amputee a completely natural gait. In India and other developing nations, having a leg amputated usually means a lifetime with a stiff, unmoving prosthetic. MIT associate professor of mechanical engineering Amos Winter wants to bring a low-tech solution to people in developing countries who don’t have $50,000 to spend on a top-of-the-line leg.

Winter and his associates published a paper detailing their research on the ideal torque that a prosthetic leg should produce in order to replicate the gait of a natural knee. Working off of that research, the team was able to build a prototype of a working prosthetic leg that uses simple elements like springs and dampers instead of high-tech electronic components.

Their low-tech prototype uses a spring to slightly bend the “knee” as the leg moves; two dampers stop the leg from swinging backward and slow it down during its forward movement just before the heel hits the ground. Using this simple system, the prosthetic leg allows for a much more natural gait than the typical non-dynamic prosthetic leg. The researchers have begun testing their invention with above-the-knee amputees in India and hope that, once refined, their prosthesis will cost only a few hundred dollars.

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Graphene, that wonder material that seems to have no limits to its usefulness, is now being used to give humans the gift of ultrasonic hearing. With the lightweight ultrasonic microphones and loudspeakers created by UC Berkeley physicists Alex Zettl, Qin Zhou, and their colleagues, people can now hear high frequencies just like dolphins and bats. The devices were made by replacing the traditional paper or plastic diaphragms found in microphones and speakers with sheets of one-atom-thick graphene. The novel material makes it possible for the devices to operate at incredible frequencies.

Humans normally hear in the 20 hertz to 20,000 hertz range while bats hear in the 9 to 200 kilohertz range. The graphene devices operate from subsonic to supersonic frequencies: from under 20 hertz to over 500 kilohertz. Because the graphene membrane is so thin, light, and responsive, it is far more efficient than current diaphragm materials. Current speakers only convert around 8 percent of received energy into sound; the graphene versions can convert over 99 percent of that energy into sound.

The ultrasonic graphene devices could be used to transmit information in electromagnetic waves through objects or even underwater – with far greater detail and reliability than traditional sonar. In the somewhat far-off future, the researchers anticipate that devices like mobile phones, speakers, and headphones will use diaphragms made of graphene sheets. But for now, the technology will be used to study high-frequency auditory signals, including the bat chirps that are normally far outside of human hearing range.

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It’s no secret that prescription drug abuse is a huge problem all around the world. The most-often abused medications are powerful painkillers, which are easy enough to misuse due to the way they’re distributed. They come in little plastic bottles, usually with a month’s worth of pills at a time. The patient can easily take more than the prescribed dose or just sell their pills to someone else.

Engineering students at Johns Hopkins University were asked to come up with a better solution that would make pill dispensation safer for the patient. They invented a tamper-resistant pill dispenser that only dispenses the correct dose at the correct time to the correct person – this is ensured with a built-in fingerprint scanner programmed right at the pharmacy. The very tough steel alloy that forms the body of the dispenser is resistant to hammers, drills, and other methods used to try to break it open.

Only a pharmacist can open the dispenser with a special key – a key which only the pharmacist has access to. The students and faculty at Johns Hopkins are still developing the technology and hope to receive a grant from the National Institutes of Health in order to continue their research and hopefully commercialize the dispenser in the future. Will it entirely prevent prescription abuse? Probably not. But at least the special dispenser will make patients more aware of the proper dosage and stop others from stealing their pills.

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Some of the best science starts with an accidental discovery, like a researcher noticing that dots of food coloring were sorting themselves, behaving much like living cells would be expected to do, chasing, dancing around and avoiding one another.

Years of research later, Nate Circa and a team of scientists have published a paper in Nature on what they discovered through subsequent experiments: “The critical fact was that food coloring is a two-component fluid. In such fluids, two different chemical compounds coexist while retaining separate molecular identities.”

“The droplets in this experiment consisted of two molecular compounds found naturally in food coloring: water and propylene glycol. The researchers discovered how the dynamic interactions of these two molecular components enabled inanimate droplets to mimic some of the behaviors of living cells.”

The video and these animated gifs illustrate the phenomena in ways that are far more intuitively easy to grasp than the complex fluid dynamics that explains the behavior – aside from simply being fascinating to watch.

“The physical properties of these fluids give rise to this immense complexity of behavior. For example, chasing and sensing each other, and very much what we call artificial chemotaxis. Chemotaxis is the idea in biology that one single cell can sense where its enemy is, and it brings up all its machinery, and it chases that enemy to try to eat it.”

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Age-related macular degeneration is the leading cause of blindness in the Western world. But help is on the way in the form of telescoping contact lenses that act like tiny, low-magnification binoculars. A team including researchers from École Polytechnique Fédérale de Lausanne, the University of California San Diego, and several other institutions have been working on the project for several years with financial backing from DARPA.

The lenses can work on their own, but they are made better with a pair of complementary glasses which respond to winks to switch between regular and magnified vision. The glasses ignore blinking, but wink with your right eye and the magnification function switches on. Wink with your left eye and the lenses switch back to normal vision.

The contacts are made from carefully shaped layers of plastics, aluminum mirrors, and polarizing thin films, all held together with biologically safe glues. Unlike the soft lenses many people wear, the telescoping contact lenses are larger and more rigid to accommodate the telescoping mechanism. One of the most challenging aspects of developing this technology has been making the lenses breathable so they can be worn for extended periods.

There are plenty of areas in which improvements need to be made before the lenses can be used in any practical capacity. But the current iteration is a promising start toward technology that can benefit the visually impaired and even help soldiers stay sharp and aware on the frontlines.

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