Methods: Divided the rats into treatment group, model group, sham operation group and normal group by sortition randomization method.

Due to current address-space randomization techniques having only limited timings to deploy randomization, this paper proposes a new method to re-randomize the address space at runtime.

Methods The study was strictly designed with randomization, double blinding, and placebo controlled method to observe the efficacy and immune memory 11 years following hepatitis B vaccination.