
Humans making use of three arms, an organic battery with more staying power, and the fastest-spinning rotor in the world — in this week’s coolest scientific discoveries, everything is just a little bit extra.
New Tech Helps You Give Yourself A Hand
What is it? Two arms not enough? Scientists at the Advanced Telecommunications Research Institute International in Kyoto, Japan, have designed a robotic arm that can function as a third appendage for those who need one — and, like the first two, can be controlled by thought. They’ve described the results in Science Robotics.
Why does it matter? Any tech development that might help people with disabilities — and mind-controlled prosthesis definitely fits the bill — is to the good, but this new creation raises prospects for people who have use of all their limbs too: Can the brain extend its own capacity for multitasking to control more arms than usual? Early signs point to yes.
How does it work? Shuichi Nichio and Christian Penaloza, the researchers behind the new brain-machine interface (BMI) system, developed algorithms that read the brainwaves of people engaged in various activities, transmitted by electrode cap. By focusing on patterns generated by firing neurons, the algorithms were able to distinguish one activity from another — and which appendage was supposed to do what. For instance, subjects were asked to use their two (biological) hands to balance a ball on a board in front of them. But say they got thirsty while doing that: By visualizing a robotic arm attached to a machine next to them grabbing a bottle of water, they were able to get it to do just that. As IEEE Spectrum explained, “The computer recorded the neural firing in their brains, sensing the intention to grasp the bottle, and performed the command.” Nishio said, “Multitasking tends to reflect a general ability for switching attention. If we can make people do that using brain-machine interface, we might be able to enhance human capability.”
Organic Batteries Are A Joule In Researchers’ Crown

This flow battery uses a new organic molecule that outlives and outperforms its predecessors. Image credit: Eliza Grinnell.
What is it? Researchers at Harvard have designed a new organic flow battery that can store energy for so long they’ve nicknamed it Methuselah, after the oldest guy in the Bible.
Why does it matter? As the world continues to transition away from fossil fuel energy, we need to figure out better ways to store energy derived from sustainable sources like wind and solar — for use when the air is still and the sky is dark. (GE Power is working on tech using lithium-ion batteries.) Building off their own previous research, the Harvard team modified a quinone — a natural compound involved in biological processes like photosynthesis — to create the “longest-lasting high-performance organic flow battery to date,” according to Harvard. Study co-leader Roy Gordon, a professor of chemistry and materials science, said, “We designed and built a new organic compound that can store electrical energy and also has a very long life before it decomposes.” The results are published in the journal Joule.
How does it work? With flow batteries, two liquid electrolytes are stored in external tanks and pumped into the cell when required; in traditional models, these electrolytes are elements dissolved in acid. But organic flow batteries make use of the same kinds of molecules that plants and animals use to store energy, like quinone. The Harvard team seized on the Methuselah quinone after a lot of experimentation that sought a balance between juice and longevity. Co-leader Michael Aziz, a professor of materials and engineering technology, explained, “In previous work, we had demonstrated a chemistry with a long lifespan but low voltage, which leads to low energy storage per molecule, which leads to high cost for a given amount of energy stored. Now, we have the first chemistry that has both long-term stability and comes in at more than one volt, which is commonly considered the threshold for commercial deployment. I believe it is the first organic-based flow battery that meets all of the technical criteria for practical implementation.”

Look me in the eye and tell me you love me and/or am among the living. Image credit: A. Czajka, P. Maciejewicz and M. Trokielewicz
What is it? Have you ever tried to use the eyes of a dead person to trick an iris scanner and gain access to a device you weren’t authorized to use? Yes, us too, definitely, but here’s some bad news: A team of Polish researchers has developed a machine-learning algorithm that can tell the difference between the eyes of the living and the dead with 99 percent accuracy. The jig’s up.
Why does it matter? It might not be the most pressing problem at the moment, but in some theoretical future where eyeball scans become standard security features, like fingerprints are now, bad actors may use the eyes of the dead to hack the system, as they did — MIT Technology Review reminds us— in the 1993 Sylvester Stallone film “Demolition Man.” As the researchers put it in their paper, “Post-mortem biometric identification is a field of study well established in the scientific community, among forensics professionals, but also in popular culture, with severed thumbs and plucked eyeballs being depicted in the big screen disturbingly often.”
How does it work? At Poland’s Warsaw University of Technology, Mateusz Trokielewicz and his partners taught the AI to tell the difference in the usual machine-learning fashion: They showed it a bunch of pictures of eyeballs from the Warsaw BioBase PostMortem Iris data set, alongside a couple hundred snaps of living irises. The computer figured out how to detect the differences, but with one catch: It could only successfully identify irises of the deceased that had been that way 16 hours or longer — it got confused by the freshly dead.
A Reliable Way To Detect Traumatic Brain Injury
What is it? A new blood test available in the U.S. can help doctors figure out if patients have experienced traumatic brain injury — an otherwise tricky condition to pin down.
Why does it matter? As the scientists behind the test note in a new paper in The Lancet Neurology, some 50 million people annually suffer traumatic brain injuries worldwide — and heretofore, doctors had to rely on patient complaints like headaches and nausea to make diagnoses. (This is an especially complicated proposition with athletes, for instance, who may downplay their symptoms in order to stay in the game.) A release from the University of Rochester Medical Center, where the test was developed, explained, “The new test provides an objective indicator of injury that can potentially be obtained quickly and easily in busy emergency departments.” The test was approved by the FDA in February as part of a “fast-track” program to get the brain-injury problem under control; now the paper with the data backing it up has been released.
How does it work? The test looks for two brain proteins found in the blood after head trauma: If the proteins are absent, the likelihood is that no traumatic intracranial injury has occurred, but if they’re present, the patient should get a CT scan. As study leader Jeffrey J. Bazarian, a professor of emergency medicine at Rochester, said, “The ability of this test to predict traumatic injuries on head CT scan will soon allow emergency physicians to provide patients with an unbiased report on the status of their brain.”
Quantum Physics That’ll Make Your Head Spin

Tongcang Li and Jonghoon Ahn believe their rotor, which spins at 60 billion revolutions per minute, will help them unlock new findings in quantum physics. Image credit:Purdue University/Vincent Walter.
What is it? Researchers from Purdue University, Tsinghua University and the Collaborative Innovation Center of Quantum Matter in Beijing have created the fastest rotor in the world — spinning at 60 billion revolutions per minute, or more than 100,000 times faster than a dental drill (and much smaller too). They published their findings in Physical Review Letters.
Why does it matter?“People say that there is nothing in vacuum, but in physics, we know it’s not really empty,” says Tongcang Li, an assistant professor of physics and astronomy, and electrical and computer engineering, at Purdue. With the technology Li’s team developed to create the rotor, they hope to increase our understanding of “the extreme conditions different materials can survive in,” including vacuumlike conditions. For quantum physics, this advance has implications for how we understand the makeup of the universe.
How does it work? The team created a tiny silica nanoparticle, shaped like a dumbbell and invisible to the naked eye, and levitated it in high vacuum using a laser that can work in one of two ways: A linear laser makes the dumbbell vibrate, and a circular laser makes it spin. As Purdue explains in a release, “A spinning dumbbell functions as a rotor, and a vibrating dumbbell functions like an instrument for measuring tiny forces and torques, known as a torsion balance. These devices were used to discover things like the gravitational constant and density of Earth, but Li hopes that as they become more advanced, they’ll be able to study things like quantum mechanics and the properties of vacuum.”