Thus Spake Paracelsus*

doses

The Swiss Renaissance physician, alchemist and founder of toxicology Philippus Aureolus Theophrastus Bombastus (!) von Hohenheim, better known as Paracelsus (Figure 1), said it well: “All substances are poisons; there is none that is not a poison. The right dose differentiates a poison and a remedy.” Or more compactly, “the dose makes the poison.” Researchers …

What Makes Sea Foam Foamy?

Last week, a handful of scientists from the Center for Sustainable Nanotechnology had the chance to visit Hawai'i for a once-every-five-years chemistry conference called Pacifichem. A few of us had a chance to go kayaking to the Mokulua (Twin Islands) near Kailua, O'ahu. While walking around Moku Nui, we had a chance to observe and discuss the …

Not Your Daddy’s Sunblock – Why Thick, White Sunblock is a Thing of the Past

As a child, I spent many summer days at the beach in southern California. I remember playing in the surf, collecting shells, watching sea lions, and seeing the white noses of the lifeguards. In those days, lifeguards smeared thick, white zinc oxide paste on their noses to protect themselves from getting sunburned When my kids …

Nanotechnology Through History: Carbon-based Nanoparticles from Prehistory to Today

Since our early ancestors first learned to make fires, humans have been producing carbon-based nanoparticles. The smoke and soot from their campfires contained nanoparticles known as fullerenes and carbon nanotubes, along with many other combustion by-products. They must have thought the very crude nanoparticle preparations they created were a bit of a nuisance (depending on …