Figure 4: Observation of A549 cell morphology under inverted biological microscope (×100), scanning electron microscope (×5000), and fluorescence microscope (×400). (a, f, k) Control; (b, g, l) 200 μmol/L acetaldehyde; (c, h, m) 40 μmol/L L-Cys + 200 μmol/L acetaldehyde; (d, i, n) 160 μmol/L L-Cys + 200 μmol/L acetaldehyde; (e, j, o) 640 μmol/L L-Cys + 200 μmol/L acetaldehyde.