Bun (hairstyle) Bun (hairstyle) A bun is a type of hairstyle wherein the hair is pulled back from the face, twisted or plaited, and wrapped in a circular coil around itself, typically on top or back of the head or just above the neck. A bun can be secured with a hair tie, barrette, bobby pins, one or more hair sticks, a hairnet, or a pen or pencil. Hair may also be wrapped around a piece called a "rat". Alternatively, hair bun inserts, or sometimes rolled up socks, may also be used to create donut-shaped buns. Buns may be tightly gathered, or
Commonly used gamma-emitting isotopes of normal non-radioactive cobalt and iridium metal in a nuclear reactor, creating radioactive nuclides of these elements which contain extra neutrons, compared to the original stable nuclides. In addition to their uses in radiography, both cobalt-60 (Co-60) and iridium-192 (Ir-192) are used in the radiotherapy of cancer. Cobalt-60 tends to be used in teletherapy units as a higher photon energy alternative to Cs-137, while iridium-192 tends to be used in a different mode of therapy, internal radiotherapy or brachytherapy. The iridium wires for brachytherapy are a palladium-coated iridium/palladium alloy wire made radioactive by neutron activation. This wire is then inserted