16 MAY 2012 by ideonexus

 Atoms Form Compounds With Properties Very Different Than ...

Compounds formed by chemical attraction, possess new properties different from those of their component parts... chemists have long believed that the contrary took place in their combination. They thought, in fact, that the compounds possessed properties intermediate between those of their component parts; so that two bodies, very coloured, very sapid, or insapid, soluble or insoluble, fusible or infusible, fixed or volatile, assumed in chemical combination, a shade or colour, or taste, solub...
Folksonomies: history chemistry
Folksonomies: history chemistry
  1  notes

It was long thought in Chemistry that compounds exhibited traits partway between their component parts.

08 JUN 2011 by ideonexus

 The Placenta and Toxicity

“During most of pregnancy, the placenta separating mother and fetus is only one cell thick,” Koren tells me. “But it has an array of mechanisms to help it do its job of protecting the fetus.” These subcellular tools, he explains, include tiny pumps that expel toxins before they can do any damage, immune agents that guard the placenta’s perimeter, and placental enzymes that chemically break down intruding molecules. This armamentarium does an impressive job of blocking bacteria from...
  1  notes

The placenta uses chemical and electrical criteria for filtering out molecules, meaning small fat-soluble molecules, even harmful ones, will pass through.