Editing Microtome (section)

===Ultramicrotome===
[[File:Microtome-ultras.jpg|thumb|200px|A ribbon of ultrathin sections prepared by room-temperature ultramicrotomy, floating on water in the boat of a diamond knife used to cut the sections. The knife blade is the edge at the upper end of the trough of water.]]

An ultramicrotome is a main tool of [[ultramicrotomy]]. It allows the preparation of extremely thin sections, with the device functioning in the same manner as a rotational microtome, but with very tight tolerances on the mechanical construction. As a result of the careful mechanical construction, the linear thermal expansion of the mounting is used to provide very fine control of the thickness.<ref name="Lang" />

These extremely thin cuts are important for use with [[transmission electron microscope]] (TEM) and [[serial block-face scanning electron microscopy]] (SBFSEM), and are sometimes also important for light-optical microscopy.<ref name="MVM" /> The typical thickness of these cuts is between 40 and 100&nbsp;nm for transmission electron microscopy and often between 30 and 50&nbsp;nm for SBFSEM. Thicker sections up to 500&nbsp;nm thick are also taken for specialized TEM applications or for light-microscopy survey sections to select an area for the final thin sections. [[Diamond knives]] (preferably) and glass knives are used with ultramicrotomes. To collect the sections, they are floated on top of a liquid as they are cut and are carefully picked up onto grids suitable for TEM specimen viewing. The thickness of the section can be estimated by the [[thin-film interference]] colors of reflected light that are seen as a result of the extremely low sample thickness.<ref>{{cite journal | author = Peachey Lee D. | title = Thin Sections: A study of section thickness and physical distortion produced during microtomy | journal = J Biophys Biochem Cytol | volume = 4 | issue = 3 | pages = 233–242 | year = 1958 | pmid =  13549493| doi = 10.1083/jcb.4.3.233| url = http://jcb.rupress.org/cgi/reprint/4/3/233.pdf | pmc = 2224471}}</ref>