  In a recent publication (D. Bolmatov et al. Sci.Rep. 5, 15850 (2015)) the
experimental observation of structural transformations on crossing the Frenkel
line in supercritical argon is claimed. Here we show that no experimental
evidence of the structural transformation was presented. The reported
experimental observations which Bolmatov et al. claim as evidence of a
transition across the Frenkel line are instead due to the irregularity of the
experimental (P,T) path in their work.
