Athenian cultural dominance continued throughout the Roman period, and the buildings added to the Agora reflect the educational role of the city, a role that ended only with the closing of the pagan philosophical schools by the Christian emperor Justinian in A.D. 529.
Bearing, in machine construction, a connector (usually a support) that permits the connected members to rotate or to move in a straight line relative to one another. Often one of the members is fixed, and the bearing acts as a support for the moving member. Most bearings support rotating shafts against either transverse (radial) or thrust (axial) loads.
In fixed-bearing implants, the bearing is firmly attached to the metal tray on the shin bone. It is fixed in position and cannot move. In rotating platform implants, the bearing can rotate or move as the knee bends, which allows for a more natural motion in the knee compared to traditional knee replacement.