Tag Archives: Chemistry

What Human Hair Reveals About Death’s Seasonality

SAPIENS

A new study demonstrates a method for deciphering the timing of a deceased person’s death using a lock of hair.

Each wave of Edith Howard Cook’s reddish-blonde hair tells a story. One segment may chronicle an unusually damp San Francisco summer; another may recall a dry December. But read in their entirety, the strands reveal the season in 1876 when 2-year-old Edith passed away.

Archaeologist Jelmer Eerkens helped identify Edith after a construction crew discovered her remains in a backyard in 2016. “I have kids myself,” says Eerkens, an archaeologist at the University of California, Davis. “So, I oftentimes think about living in the 1800s. And children dying was just a common thing.”

By 1900, for example, children under the age of 5 accounted for 30 percent of all deaths in the U.S.—often from tuberculosis and flu, which fluctuate with the seasons. “Your kid gets sick: Are they going to die? Are they going to live? It must have been heart-wrenching,” Eerkens notes.

In a new study published in the American Journal of Physical Anthropology, Eerkens and his colleagues introduce a method to decode the season of an individual’s death using hair.

Read the full story in SAPIENS

Republished by The Atlantic

Are Forever Chemicals Harming Ocean Life?

THE REVELATOR

Here’s what we know (and don’t know) about how dangerous PFAS chemicals travel ocean currents and harm wildlife — and what that could mean for humans.

In seabird after seabird, Anna Robuck found something concerning: per- and polyfluoroalkyl substances, or PFAS, lurking around vital organs.

“Brain, liver, kidney, lung, blood, heart,” Robuck says, rattling off a few hiding spots before pausing to recall the rest. Robuck, a Ph.D. candidate in chemical oceanography at the University of Rhode Island, quickly settles on a simpler response: She found the chemicals everywhere she looked.

PFAS — a group of synthetic chemicals — are often called “forever chemicals” due to their quasi-unbreakable molecular bonds and knack for accumulating in living organisms. That foreverness is less of a design flaw than a design feature: The stubborn, versatile molecules help weatherproof clothing; smother flames in firefighting foam; and withstand heat and grime on nonstick pans.

Through consumption and disposal, the chemicals seep into ecosystems and bodies, where they have been linked to cancers, pregnancy complications, and reproductive and immune dysfunction. Recent attention has focused on the prevalence of PFAS in drinking water.

“Over the past 10-15 years we’ve really developed this super negative picture of what PFAS do to humans,” Robuck says. “But we’ve barely scratched the surface of that in wildlife.”

Read the full story in The Revelator

To Make Oxygen on Mars, NASA’s Perseverance Rover Needs MOXIE

SMITHSONIAN

A new tool from the space agency may produce the gas, completing the next step for planning a round trip voyage

Putting boots on Mars isn’t easy, but it’s a lot easier than bringing them back.

This week, NASA launches its Perseverance rover on a one-way trip to the surface of Mars. Among many other tools, the craft carries an experimental instrument that could help astronauts in the future make roundtrip voyages to the planet. The Mars Oxygen In-Situ Resource Utilization Experiment, or MOXIE, is small, about the size of a car battery. It’s designed to demonstrate a technology that converts carbon dioxide into oxygen with a process called electrolysis. Mars’ thin atmosphere is 95 percent carbon dioxide, but sending anything back into space requires fuel, and burning that fuel requires oxygen. NASA could ship liquid oxygen to the planet, but the volume needed takes up a good deal of space.

MOXIE could show the way to a solution.

Read the full story in Smithsonian

Decoding the chemistry behind cicada’s bacteria-killing wings

CHEMISTRY WORLD

Meticulously organised fatty acids are responsible for the bacteria-killing, superhydrophobic nanostructures on cicada wings. The team behind the discovery hopes that its work will inspire antimicrobial surfaces that mimic cicada wings for use in settings such as hospitals.

When in contact with dust, pollen and – importantly – water, the cicadas’ superhydrophobic wings repel matter to self-clean. These extraordinary properties are down to fatty acid nanopillars, periodically spaced and of nearly uniform height, that cover the wings.

Past work has generally only described cicadas’ wings as ‘waxy’ and not explained how these fatty acids nanopillars give rise to unique traits. Nor is it known exactly why cicada wings evolved antibacterial nanostructures. These gaps in our knowledge exist, in part, because of how diverse the cicada family is. But Marianne Alleyne’s group at the University of Illinois, Urbana–Champaign, along with colleagues at Sandia National Labs, set out to understand what role chemistry plays in the wings of two evolutionarily divergent species.

Read the full story in Chemistry World