|Platelet-activating factor (PAF) is a potent phospholipid activator of g-protein coupled receptor. It also acts as as a mediator of biological functions such as platelet aggregation and degranulation, inflammation, and anaphylaxis at very low concentrations. It is also responsible for changes in vascular permeability and chemotaxis and oxidative burst of leukocytes.The impact factor of journal provides quantitative assessment tool for grading, evaluating, sorting and comparing journals of similar kind. It reflects the average number ofÂ citationsÂ to recent articles published inÂ science and social science journals in a particular year or period, and is frequently used as aÂ proxyÂ for the relative importance of a journal within its field. It is first devised byÂ Eugene Garfield, the founder of theÂ Institute for Scientific Information. The impact factor of a journal is evaluated by dividing the number of current year citations to the source items published in that journal during the previous two years.