This rat study examined whether pulse-modulated 900 MHz and 1800 MHz RF exposure affects blood-brain barrier permeability using Evans blue dye. The abstract reports increased permeability in male rats at both frequencies (stronger at 1800 MHz) and in female rats at 900 MHz but not at 1800 MHz. The authors suggest mobile-phone-like RF exposure could increase blood-brain barrier permeability under non-thermal conditions, while noting that further mechanistic studies are needed.