Effects of fixative on stain uptake.
(a) Stained volume of the dorsoventral flight muscles against the number of days stained for ETH-PTA and PFA-PTA preparations. The error bars shown are calculated based on the uncertainty in the reconstructed voxel size; the focal spot size of the μCT scanner is 1 μm, therefore the error bars show the volume sizes for ±0.5 μm of the calculated volume. (b) Staining levels for the PFA-PTA specimen across days 3, 5 and 7. Each slice shown is from approximately the same 2D plane taken from the 3D volume. Each image is a 16-bit greyscale image; higher greyscale values indicate a higher level of staining. (c) Staining levels for the ETH-PTA specimen across days 3, 5 and 7.