Cutting through clots, finding Earth’s inner-inner core, and getting to the root of Alzheimer’s disease. This week’s coolest things dig deep.

What is it? North Carolina State University engineers developed a tool that breaks up brain blood clots quickly with an ultrasonic tornado, potentially reducing risk for patients.
Why does it matter? Current treatments fail in 20% to 40% of patients with cerebral venous sinus thrombosis (CVST), a leading cause of stroke in young people. “Existing techniques rely in large part on interventions that dissolve the blood clot. But this is a time-consuming process,” said Chengzhi Shi, co-corresponding author of a study in Research. “Our approach has the potential to address these clots more quickly.”
How does it work? The tool consists of a single transducer, small enough to fit into a catheter that can be threaded into a blocked vein. It produces an ultrasonic wave that travels in a swirling, helical path. The wave breaks up a clot with shear force, dissolving it in a matter of minutes, versus hours or a day for pharmaceutical treatments.

What is it? Seismologists from the Australian National University found evidence that inside the Earth’s core is a smaller, innermost core.
Why does it matter? “The existence of an internal metallic ball within the inner core, the innermost inner core, was hypothesized about 20 years ago. We now provide another line of evidence to prove the hypothesis,” said Thanh-Son Pham, coauthor of a paper in Nature Communications.
How does it work? Pham and his collaborator studied the reverberations of large earthquakes that traveled through the planet’s core and “bounced” back to their point of origin. Comparing the travel times of the seismic waves, they inferred that there is a center region that is different from the outer layer of the core — a newly identified fifth layer of the Earth.

What is it? Scientists at the University of Washington discovered two previously unknown forms of frozen salt water.
Why does it matter? The finding may help researchers who are working to make sense of unfamiliar chemical structures on other planets in the solar system. While trying to study how salt affects the formation of ice on much colder planets under much higher atmospheric pressure, Baptiste Journaux and his team made what he called a rare “fundamental” discovery.
How does it work? They compressed salt water at up to 25,000 times Earth’s atmospheric pressure while lowering the temperature below –190 degrees Fahrenheit. Surprisingly, ice crystals began forming in arrangements never before seen on Earth. When salt water freezes naturally on Earth, it arranges into a lattice structure of one salt molecule for every two water molecules. In the experiment, published in PNAS, salt water froze in different arrangements (two salt molecules for every 17 water molecules and one salt molecule for 13 water molecules), consistent with the chemical signatures observed on other planets’ ice moons.

What is it? Biotech researchers at the University of California, Santa Barbara, re-created the early stages of Alzheimer’s disease in the lab.
Why does it matter? Tangled proteins inside brain cells are a hallmark of Alzheimer’s, but scientists are unclear on their role — whether, for instance, they are a cause of the disease or result from another underlying issue. The UCSB team’s work, published in the Journal of Biological Chemistry, creates a way to simulate the tangling of these proteins to study the tipping point into Alzheimer’s.
How does it work? Tau proteins naturally fold to create a scaffolding that helps brain cells function properly. The folding can sometimes get out of control, though, and this hyperfolding is seen in many cases of Alzheimer’s. The researchers used a small electric current to mimic the molecular signaling that leads to hyperfolding. “This method provides scientists a new means to trigger and simultaneously observe the dynamic changes in the protein as it transitions from good to bad,” said UCSB’s Daniel Morse.

What is it? MIT researchers devised a method for direct removal of carbon dioxide from seawater.
Why does it matter? Oceans absorb around a third of carbon emissions. Pulling carbon from the ocean could be more efficient than atmospheric carbon capture, as the concentration of CO2 in seawater is 100 times greater than in air. And since the oceans are large carbon sinks, “the capture step has already kind of been done for you,” said Kripa Varanasi, an author of a study in Energy & Environmental Science.
How does it work? The method relies on electrodes that release protons into the water, which convert dissolved carbon into CO2 gas that is collected to be reused or stored. Another set of electrodes recovers the protons, releasing alkalized water back into the sea. This has the added benefit of locally reversing ocean acidification that harms coral and other marine life. A collection system could be added to existing infrastructure that already processes seawater, such as desalination plants.