Androgens are metabolized to estrogens via CYP19A, also known as aromatase, a liver-produced enzyme of the cytochrome P450 family responsible for drug metabolism.
About 300-400 years ago, the letter s, when used within a word, was written like the letter f, but without the horizontal line. See, for example, the cover page of Milton's Paradise Lost: http://en.wikipedia.org/wiki/Image:Milton_paradise.jpg
Possible carry-over from similar practices in the greek language?
An RFID tag is an object that can be applied to or incorporated into a product, animal, or person for the purpose of identification using radio waves. Some tags can be read from several meters away and beyond the line of sight of the reader.