Spectroscopic analysis of keratin endogenous signal for skin multiphoton microscopy
We recorded one-photon excited fluorescence (1PEF) and two-photon excited fluorescence (2PEF) spectra of purified keratin from human epidermis, and determined the action cross section of this endogenous chromophore. We used this spectroscopic analysis to analyse multiphoton images of skin biopsies and assign the intrinsic fluorescence signals in the epidermis. We observed a good agreement between in situ and in vitro 2PEF spectra of keratin. This study provides a comprehensive characterization of the 2PEF signal of the keratins from the epidermis, and will be of practical interest for multiphoton imaging of the skin.
Exact eigenvalues, normalized electronic wavefunctions and their derivatives with respect to the internuclear separation have been calculated for the lowest 20 states 1s sigma , 2s sigma ,...,4f phi of the HeH2+ molecule at internuclear separations 0.1(0.1)20, 20(0.2)80 a0 assuming infinitely massive nuclei. The numerical importance of the correct exponential form of the wavefunctions is emphasized, and the states are unambiguously correlated to their separated-atoms limits. The molecular states 2p sigma , 4f sigma and 4f pi are bound; their equilibrium parameters have been determined.