(left to right): ANGEL YANAGIHARA; How The Eye Functions/Prelinger Archive; INTERNATIONAL BUREAU OF WEIGHTS AND MEASURES

Top stories: jellyfish stingers, eye-swimming microbots, and a metric system makeover

Jellyfish almost killed this scientist. Now, she wants to save others from their fatal venom

Angel Yanagihara of the University of Hawaii in Honolulu has spent 20 years studying the venom of box jellyfish and working to prove their stings exact a much higher death toll than commonly assumed. Her studies have illuminated the biochemical mechanism behind the venom’s lethality and helped her develop products that she says counter the sting. But other jellyfish researchers say different compounds in the venom are the real killers, and that different remedies—or none at all—are better for victims.

Watch tiny robots swim through an eyeball to deliver medicine

Although the thought of a swarm of microbots burrowing into an eyeball is enough to make people squirm, researchers have developed spiral-shaped robots tiny enough to pass through dense eyeball jelly. The bots could one day provide a more targeted method of delivering medicine to hard-to-reach areas at the back of the eye.

Metric system overhaul will dethrone the one, true kilogram

Le Grand K, a gleaming cylinder of platinum-iridium alloy and the world’s standard for mass for more than 130 years, is set to be dethroned as the one, true kilogram. The 26th General Conference on Weights and Measures convenes next week in Versailles, France, and representatives are expected to vote to redefine the International System of Units so that four of its base units—the kilogram, ampere, kelvin, and mole—are defined indirectly, in terms of physical constants that will be fixed by fiat. The rewrite, taking effect in May 2019, aims to make the units more stable and allow investigators to develop ever more precise and flexible techniques to mete them out.

Frequent inbreeding may have caused skeletal abnormalities in early humans

A new study of fossilized skeletons from across the Middle East and Eurasia found that ancient humans suffered from an unusually high number of birth defects, both debilitating and relatively inconsequential. It’s unclear why such abnormalities seem to be so common, but scientists say one strong possibility is rampant inbreeding among small hunter-gatherer groups.

NSF reviewing program that allows graduate fellows to study abroad

The National Science Foundation has pressed pause on the Graduate Research Opportunities Worldwide program, an add-on to the organization’s flagship Graduate Research Fellowship program. NSF says it is “currently reviewing possible future directions” for the program, through which students already receiving the $34,000-a-year fellowship can apply for an additional $5000 allowance to cover travel and living expenses incurred while studying abroad.