Quantitative research is based on numerical data. See also free radical. Randomization is done to cancel out the influence of factors that are not under study. See aphthous ulcer. When chemical messengers bind to receptors, various cellular functions are activated or inhibited.
Many drugs exert their effects by binding to receptors and altering normal cellular communication.
Rechallenge may be done after vaccination to determine whether a vaccine was effective. The syndrome may occur following other diseases such as chlamydiasis or salmonellosis. Statistically, RR is the chance that a person receiving an exposure will develop a condition compared to the chance that a non-exposed person will develop the same condition. Replicative enzymes of HIV include reverse transcriptase, protease and integrase. Contrast with susceptible.