During activation, the single chain protein of the native factor XII is cleaved into two chains (50 and 28 kDa), which remain linked by a disulphide bond. The light chain (28 kDa) contains the active site and the molecule is referred to as activated Hageman factor (factor XIIa).
A spring tide refers to the 'springing forth' of the tide during new and full moon. A spring tide is a common historical term that has nothing to do with the season of spring. Rather, the term is derived from the concept of the tide springing forth.. Spring tides occur twice each lunar month all year long without regard to the season.
Spring Tides. When the moon is full or new, the gravitational pull of the moon and sun are combined. At these times, the high tides are very high and the low tides are very low. This is known as a spring high tide. Spring tides are especially strong tides (they do not have anything to do with the season Spring). They occur when the Earth, the Sun, and the Moon are in a line. The gravitational forces of the Moon and the Sun both contribute to the tides. Spring tides occur during the full moon and the new moon. Neap Tides. During the moon's quarter phases the sun and moon work at right angles, causing the bulges to cancel each other. The result is a smaller difference between high and low tides and is known as a neap tide. Neap tides are especially weak tides.