APPLIED PHYSICAL SCIENCES. For the article “Ionic contrast terahertz near-field imaging of axonal water fluxes,” by Jean- Baptiste Masson, Martin-Pierre Sauviat, Jean-Louis Martin, and Guilhem Gallot, which appeared in issue 13, March 28, 2006, of Proc Natl Acad Sci USA (103:4808–4812; first published March 17, 2006; 10.1073/pnas.0510945103), the authors note that in Fig. 1 the y scale is incorrect because of a unit conversion error. The corrected figure and its legend appear below. This error does not affect the conclusions of the article.
Fig. 1.
Amplitude absorption spectra of KCl (solid line), NaCl (dashed line), and CaCl2 (dotted line), subtracted by the spectrum of double deionized water. The concentrations are below 100 mM. Absorption is given by the amplitude molar extinction coefficient ε, defined as T/T0 = eεCl, where T and T0 are the ion and water terahertz amplitude signals, C is the ion concentration, and l is the sample thickness.