390: Up to Date | Nanoparticle toothbrushes and a promising Alzheimer's drug

This week: new research into using nanoparticles and programmable magnets to clean your teeth; a potentially breakthrough study on a drug for Alzheimer's disease featuring the first positive trial ever for a disease of aging; recapping NASA’s recent Double Asteroid Redirection Test mission; and a look into how much control you actually have over what Youtube decides to show you.