Sentence:  The DEAE-cellulose , containing 0.78 mEq of N / g , was prepared in our laboratory by the method of Peterson and Sober ( 7 ) from powdered cellulose , 100 - 230 <WSD>mesh</WSD> . 
Meaning of the word marked with <WSD> tags:  the number of openings per linear inch of a screen; measures size of particles