Interphase : Interphase, which appears to the eye to be a resting stage between cell divisions, is actually a period of diverse activities. Those interphase activities are indispensible in making the next mitosis possible. Interphase generally lasts at least 12 to 24 hours in mammalian tissue. During this period, the cell is constantly synthesizing RNA, producing protein and growing in size. By studying molecular events in cells, scientists have determined that interphase can be divided into 4 steps: Gap 0 (G0), Gap 1 (G1), S (synthesis) phase, Gap 2 (G2).
In order to derive the safety rating, the test results are weighted according to the best motorcycle accident data available. This weights the likelihood of impacts occurring to different regions of the helmet, of impacts occurring at different speeds, and of impacts with different surfaces, based upon the accident studies carried out as part of the COST 327 study. This found the side and rear of the helmet to be commonly impacted and a strong correlation between impact location on the helmet and injury. The side of the head was also found to be particularly vulnerable to injury. The weighting of test results during the calculation of the SHARP safety ratings to real world accident data aims to highlight those helmets that will make the most difference to motorcyclist safety.