Sentence:  After automated particle <WSD>preselection</WSD>, manual verification, and selection by cross-correlation, 18,801 particles were chosen for the vacant 40"S "subunit, 20,939 particles for the IRES-40"S "complex, and 13,613 particles for the IRES dII-40"S "complex. 
Meaning of the word marked with <WSD> tags:  Selection in advance