Biological clocks and the surprising speed of human regeneration

Gut markers of aging. University of Hawaiʻi at Mānoa researchers found that gut bacteria composition accounts for 15 percent of the variation in human aging, with Bifidobacterium adolescentis linked to slower biological decline (Forever Young). This internal clock operates alongside the rapid turnover of the digestive tract, where stem cells replace the entire intestinal lining every three to five days (Stephen Thomas BSc).

Cellular renewal limits. Carbon-14 data reveals that while the human skeleton remodels itself roughly every ten years, the total number of fat cells in an adult remains remarkably constant despite weight fluctuations. Arizona State University scientists mapping the dog epigenome discovered that larger breeds age faster due to jumping genes, providing a model for how DNA methylation influences lifespan across species (Ars Technica Science).

Brain plasticity constraints. University of South Carolina researchers determined that the condition of the healthy side of the brain predicts language recovery after a stroke, regardless of the lesion's size (Better Brain). Stanford-led teams using xenocortication transplanted human neurons into mice, observing the human tissue integrate into the rodent nervous system and fire in patterns resembling a third-trimester fetus (Tee Ashby).

• Physicists successfully trapped a single particle of antimatter for months, a feat that could explain why the universe exists despite theoretical imbalances (Ars Technica Science, The Weird Science Drop).
• Amazon river dolphins exhibit a unique behavior of urinating into the air, a practice researchers suspect may signal social position or physical condition (New Scientist).