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. Author manuscript; available in PMC: 2022 Jan 7.
Published in final edited form as: Methods Cell Biol. 2019 Jun 8;152:41–67. doi: 10.1016/bs.mcb.2019.04.004

Figure 1. Schematic of typical block face shapes and a prediction on how they are picked up by the tape.

Figure 1.

(A) A properly trimmed trapezoid block face tends to give sections that form ribbons. This shape is desirable when the block face is small. (B) A properly trimmed rectangular block face tends to give sections that are picked up independently. (C) An elongated hexagonal-shaped block face eliminates the formation of ribbons. (D) Example of an inappropriately trimmed block face. The leading and trailing edges are not parallel to each other. This leads to an abrupt rotation of the section after the trailing edge is cut, which may lead to some sections becoming stalled on the knife boat. (E) Example of an inappropriately trimmed block face. The trailing edge is longer on one side than the leading edge. The hanging edge tends to stick to the diamond knife edge, impeding the section from moving towards the tape. (F) Example of an inappropriately trimmed block face. The tips of the hexagonal-shaped block face do not align with each other, causing the sections to rotate in the knife boat.