Tomography is the imaging by sections or sectioning. The technique is particularly suitable for optical sectioning at lower magnifications. Then the glass knife is replaced by a diamond blade for the actual ultrathin sectioning. Optical sectioning is underdeveloped in non-light microscopes. This requires proper tissue collection, fixation and sectioning. This "missing cone" is a well-known problem that prevents optical sectioning using a wide-field microscope. Oil immersion objectives typically have even larger numerical apertures so improved optical sectioning. Metabolic functions in eukaryotes are more specialized as well by sectioning specific processes into organelles. Differential interference contrast (DIC) provides modest improvements to optical sectioning. Thin sectioning is used to determine the provenance of the stone blades. The best samples come from felling a tree and sectioning it. It can be use in 3-D to achieve the frequency sectioning. SINEs are characterized by their different modules, which are essentially a sectioning of their sequence. For two years following her sectioning, Mirza's health deteriorated.