Science Daily·Friday, December 19, 2025

Science Daily - Friday, December 19, 2025

10 stories~15 min

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Stories Covered

The 98% mystery: Scientists just cracked the code on “junk DNA” linked to Alzheimer’s

Researchers have revealed that so-called “junk DNA” contains powerful switches that help control brain cells linked to Alzheimer’s disease. By experimentally testing nearly 1,000 DNA switches in human astrocytes, scientists identified around 150 that truly influence gene activity—many tied to known Alzheimer’s risk genes. The findings help explain why many disease-linked genetic changes sit outside genes themselves. The resulting dataset is now being used to train AI systems to predict gene cont

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An 11-year-old needed two new organs and doctors made history

In a rare and historic achievement, Children’s Hospital Colorado successfully completed its first dual heart and liver transplant in a pediatric patient. The life-saving surgery was performed on 11-year-old Gracie Greenlaw, whose congenital heart condition eventually led to liver failure. Dozens of specialists worked together for years to prepare for a moment like this, executing a complex, 16-hour operation. Now months later, Gracie is home, in school, and thriving.

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Neurons aren’t supposed to regrow but these ones brought back vision

After injury, the visual system can recover by growing new neural connections rather than replacing lost cells. Researchers found that surviving eye cells formed extra branches that restored communication with the brain. These new pathways worked much like the originals. The repair process, however, was slower or incomplete in females, pointing to important biological differences in recovery.

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A stunning new forecast shows when thousands of glaciers will vanish

New research reveals when glaciers around the world will vanish and why every fraction of a degree of warming could decide their fate.

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The gear meant to protect firefighters may carry hidden dangers

Firefighter turnout gear is designed to shield first responders from extreme heat and danger, but new research suggests it may also introduce chemical exposures. A U.S. study found that brominated flame retardants are present across multiple layers of firefighter gear, including newer equipment marketed as PFAS-free. In some cases, these chemicals appeared at higher levels than the substances they were meant to replace.

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A hidden T cell switch could make cancer immunotherapy work for more people

Scientists have discovered that T cell receptors activate through a hidden spring-like motion that had never been seen before. This breakthrough may help explain why immunotherapy works for some cancers and how it could be improved for others.

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Helping others for a few hours a week may slow brain aging

Spending a few hours a week helping others may slow the aging of the brain. Researchers found that both formal volunteering and informal acts, like helping neighbors or relatives, were linked to noticeably slower cognitive decline over time. The benefits added up year after year and didn’t require a huge time commitment. Even modest, everyday helping packed a powerful mental payoff.

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Ancient oceans were ruled by super predators unlike anything today

Long before whales and sharks, enormous marine reptiles dominated the oceans with unmatched power. Scientists have reconstructed a 130-million-year-old marine ecosystem from Colombia and found predators operating at a food-chain level higher than any seen today. The ancient seas were bursting with life, from giant reptiles to rich invertebrate communities. This extreme complexity reveals how intense competition helped drive the evolution of modern marine ecosystems.

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Earth may have been ravaged by “invisible” explosions from space

Cosmic “touchdown airbursts” — explosions of comets or asteroids above Earth’s surface — may be far more common and destructive than previously thought, according to new research. Unlike crater-forming impacts, these events unleash extreme heat and pressure without leaving obvious scars, making them harder to detect.

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Gravitational waves may reveal hidden dark matter around black holes

Gravitational waves from black holes may soon reveal where dark matter is hiding. A new model shows how dark matter surrounding massive black holes leaves detectable fingerprints in the waves recorded by future space observatories.

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