log-fsc x log-ssc vs lin-fsc x lin-fsc and FL1

Ray Hicks rh208 at cus.cam.ac.uk
Fri Aug 21 07:58:22 EST 1998


It could be that you've got so many "noise events" (elctronic noise, air
bubbles,  cell debris, other small particulate contaminants,etc) when
you're running with a log amp on FSC that the cells are swamped out
(presuming that you're triggering on FSC).  Did you get the same event rate
with log and lin? If it was appreciably higher on log then it would back
the idea that a lot of events were noise, and you should try pushing the
trigger threshold higher until a reasonable number of events are


  At 3:17 pm -0400 20/8/98, Janssen, William wrote:
>We have just completed, using a Facscalibur, analysis of the presence of
>a genetically engineered surface marker on renal carcinoma cells.
>Because a log-ssc x log-fsc representation gave a nice cluster of
>events, we used those scales to acquire. But to our dismay, when
>examining the FL1 histogram, it appeared that no cells were expressing
>the protein being stained for. Subsequent acquisition using linear
>scales for both fsc and ssc, showed substantial staining on the same
>We are at a loss to account for why this should be so. Anybody out there
>have an idea? Anybody at B-D want to explain?
>Thnx Vry Mch!!!
>William E. Janssen, Ph.D.
>Associate Professor
>University of South Florida / H. Lee Moffitt Cancer Center
>12902 Magnolia Drive, Tampa, FL 33612, U.S.A.
>phone: 1-813-979-7202; fax 1-813-979-3071

                              Ray Hicks
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