Wavelet analysis of corneal endothelial electrical potential difference   reveals cyclic operation of the secretory mechanism
  There is evidence that the electrical potential difference of corneal endothelium (TEPD) is related electro-osmotically to fluid transport. Hence, determination of the TEPD would serve as a measure of the fluid movement. The oscillatory nature of the TEPD has been recognized recently using the Fourier transform; the oscillations of the highest amplitude were linked to the operation of electrogenic sodium-bicarbonate cotransporters. However, no time localization of that activity could be obtained with the Fourier methodology utilized. For that reason we now characterize the TEPD using wavelet analysis for the first time in the epithelial physiology field, with the aim to localize in time the variations in TEPD. We find that the high-amplitude oscillations of the TEPD are cyclic, with a period of 4.6 \pm 0.4 s in the average (n=4). The wavelet power value at the peak of such oscillations is 1.5 \pm 0.1 mV2 Hz in the average (n=4), and is remarkably narrow in its distribution. 
Veronica Ines Cacace, Nicolas Montalbetti, Carlos Kusnier, Martin   Pedro Gomez, and Jorge Fischbarg
physics.bio-ph