WebZine
2019. 7
What's New
One of them seen here next to a US penny, the robots weigh about 5 milligrams each – jumping and swimming versions are in the works(Credit: Allison Carter, Georgia Tech)
If you're making a 2-mm-long walking robot, it pretty much goes without saying that the thing won't be able to carry much of a battery. That's why Georgia Tech's new "micro-bristle-bots" are instead propelled by vibrations. And someday, they may actually be capable of moving within the human body.
The robots are 3D printed out of polymer resin, via a process known as two-photon polymerization lithography. Each one has either four or six springy "legs," which are really more like bristles – hence the name. Additionally, glued onto the back of each bot is a piezoelectric actuator made of lead zirconate titanate.
When vibrations are delivered to the robot via either a shake table, an external ultrasound/sonar source, or a tiny acoustic speaker, those vibrations cause the angled legs to move up and down, propelling the robot forward. The onboard actuator can also produce the vibrations when subjected to an electrical current, although that current presently has to come from a hard-wired source. Down the road, however, it may be possible to wirelessly activate the actuator using electrical fields.
The amplitude of the vibrations determines the speed at which the robots move. What's more, by tweaking their legs' size, diameter, and overall geometry, the bots can be designed to respond to different vibrational frequencies. Therefore, by linking together two differently-designed robots that respond to different frequencies, it should be possible to steer the two by varying the frequency and amplitude of the vibrations.
Hundreds of the devices have already been created, and the researchers are now looking at ways of scaling up the manufacturing process, so that thousands could be made at once. Possible applications include the movement of materials within tiny spaces, or even the treatment of injuries within the body. And, because the actuators can be tuned to generate an electrical current when exposed to vibrations (the opposite of what they usually do), the robots could also carry environmental sensors that are temporarily powered up as needed.
With This AI, 60 Percent of Patients Who Had Surgery Could Have Avoided It
Machine learning algorithms that combine clinical and molecular data are the “wave of the future,” experts say
by Megan Scudellari
Photo: iStock
A man walks into a doctor’s office for a CT scan of his gallbladder. The gallbladder is fine but the doctor notices a saclike pocket of fluid on the man’s pancreas. It’s a cyst that may lead to cancer, the doctor tells him, so I’ll need to cut it out to be safe.
It’ll take three months to recover from the surgery, the doctor adds—plus, there’s a 50 percent chance of surgical complications, and a 5 percent chance the man will die on the table.
An estimated 800,000 patients in the United States are incidentally diagnosed with pancreatic cysts each year, and doctors have no good way of telling which cysts harbor a deadly form of cancer and which are benign. This ambiguity results in thousands of unnecessary surgeries: One study found that up to 78 percent of cysts for which a patient was referred to surgery ended up being not cancerous.
Now there’s a machine learning algorithm that could help. Described today in the journal Science Translational Medicine, surgeons and computer scientists at Johns Hopkins University have built a test called CompCyst (for comprehensive cyst analysis) that is significantly better than today’s standard-of-care—a.k.a. doctor observations and medical imaging—at predicting whether patients should be sent home, monitored, or undergo surgery.
“We are extremely excited about the results of this,” said senior author Anne Marie Lennon, director of the pancreatic cyst program at the Johns Hopkins Kimmel Cancer Center, at a press conference about the study. She expects to offer the test to Hopkins patients within 6 to 12 months and hopes to make it commercially available following a larger, prospective clinical trial.
The vast majority of pancreatic cysts are benign, but right now doctors track them all, said study author Christopher Wolfgang, director of surgical oncology at the Kimmel Cancer Center. “We need to follow all patients, on the order of hundreds of thousands of patients, with expensive and, in some cases, invasive tests to find those few patients who will progress to cancer.” Follow-up testing can involve radiation exposure and complications, as well as provoke anxiety, he adds.
Lennon, Wolfgang, and others set out to build a tool to sift through patient information in the hopes of identifying patterns to distinguish low-risk from high-risk cysts. To do so, they gathered data from hundreds of patients at Hopkins and 15 medical centers around the world who were diagnosed with a cyst and then underwent surgery to have it removed. After surgery, each cyst was examined and classified as having either no risk, a small risk, or a high risk of progressing to cancer.