Dan Sessler

They literally 3D-printed an eyeball. And the blind guy can see again. Not a chip. Not a sensor. A full living human eye — retina, cornea, lens, optic nerve — built layer by layer in a printer. Bioengineers at KAIST in South Korea pulled it off. The whole thing took 6 hours to print. Living retinal cells stacked in precise layers with their own blood vessels. A hydrogel lens that auto-focuses. Biocompatible polymers shaping the white of the eye. And an optic nerve scaffold designed to guide fresh nerve growth straight to the brain. Then they put it inside a 31-year-old man who lost his sight 7 years ago in an industrial accident. Three weeks later, his brain started decoding the signals. He's now seeing at 20/60. Reading. Recognising faces. Naming colours. This is the first time a complex organ made of multiple tissue types has been printed AND successfully wired into the human nervous system. Science fiction quietly clocked out. Science just clocked in.

The time of day that you run is physiologically important ⏰ When you run in the hot part of the day... 1/ Your stroke volume decreases (less blood volume available to fill the heart) leading to less cardiac remodeling. 2/ Your pace for a given HR is lower leading to less active muscle fibers being trained. A central aim of training is for higher & higher threshold motor units to be recruited & trained. This requires your training speeds to progressively increase over time. So, if you want to get better, for most of your runs... Stay cool 😎