“…To add more complications, some speci®c effects required a precise combination of different exposure parameters, e.g., the carrier frequency and pulse repetition rate [Gapeev et al, 1994;Semin et al, 1995b] or the modulation frequency and the radiation intensity [Blackman et al, 1980;Adey, 1988;Dutta et al, 1989;Schwartz et al, 1990]. Since the windows often are very narrow, the experimental search for unique combinations of different exposure parameters among the innumerable possibilities is problematic, and it is no wonder that many attempts to reveal the effectiveness windows by probing various combinations of exposure parameters resulted in negative ®ndings [Chou and Guy, 1978;Bush et al, 1981;Liu et al, 1982;Pakhomov et al, 1992Pakhomov et al, , 1995. More information and discussion of window phenomena can be found in specialized reviews on pulsed microwave bioeffects [Blackwell and Saunders, 1986;Postow and Swicord, 1986;Pakhomov and Murphy, 2000].…”