Sentence:  They include a critical step of vacuum embedding the specimen, as well as cutting and mounting individual serial sections, as opposed to the traditional method described of preparing and mounting an entire block followed by <WSD>resectioning</WSD> to produce a thinner mounted sample (Neese 2004). 
Meaning of the word marked with <WSD> tags:  To thinly slice a specimen as part of its preparation, such as when preparing a microscope slide.