RE: SEM

vanburen%flovax.dnet.wayne.edu@rocdec.roc.wayne.edu
Fri, 2 Aug 1996 16:17:37 -0400

>A friend of mine is not sure whether he would like to get a SEM for his
>Ventage. He's going to sort mainly the neoplastic cells. Any suggestions or
>advice? Thanx.
>
The SEM works well. Even though my fluorescense regions are usually
rectangular, my FSC/SSC region is usually non-rectangular (polygon). Keep
in mind, however, that with Consort32 (HP LYSYS II), you cannot use the SEM
with the ACDU. With a FACStation (CellQuest), you CAN use both at the same
time. Also, don't forget that you can use logical gates with the SEM; with
the standard sort comparitors, you essentially only get the AND function.
This is helpful, for instance, when I want to sort G1=R1 AND R2, and also
collect the "non-sort" G2=R1 AND NOT R2, (R1 is FSC/SSC, and R2 is
fluorescense). This is trivial if R2 is a histogram region, but no so if R2
is defined on two parameters, FLx/FLy.

>This made me wonder how 'elliptical' really the SEM elliptical gates are?
>Does anybody know the degree of approximation of ellipses the SEM uses? How
>many chanels wide are the little rectangles at the edges? Or is it
>completely different than I imagine?
>
The SEM uses the elliptical (or polygonal, or trapezoidal, or rectangular)
regions drawn by either HP LYSYS II or CellQuest. Both programs are capable
of making "pointy" ellipses that have 1-channel wide edges. The SEM sees
regions as "bitmaps". I'm not sure what the resolution of the bitmap is.

/\/\/\_ Eric Van Buren, vanburen%flovax.dnet@rocdec.roc.wayne.edu
\ \ \ Karmanos Cancer Institute and Wayne State University
\_^_/ Immunology & Microbiology, Detroit, Michigan

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CD-ROM Vol 3 was produced by Monica M. Shively and other staff at the Purdue University Cytometry Laboratories and distributed free of charge as an educational service to the cytometry community. If you have any comments please direct them to Dr. J. Paul Robinson, Professor & Director, PUCL, Purdue University, West Lafayette, IN 47907. Phone: (765)-494-0757; FAX(765) 494-0517; Web http://www.cyto.purdue.edu , EMAIL cdrom3@flowcyt.cyto.purdue.edu

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CD-ROM Vol 3 was produced by Monica M. Shively and other staff at the Purdue University Cytometry Laboratories and distributed free of charge as an educational service to the cytometry community. If you have any comments please direct them to Dr. J. Paul Robinson, Professor & Director, PUCL, Purdue University, West Lafayette, IN 47907. Phone: (765)-494-0757; FAX(765) 494-0517; Web http://www.cyto.purdue.edu , EMAIL cdrom3@flowcyt.cyto.purdue.edu