Gday again, Joseph. This is one I can't resist! Read that as "I can't remain psilent!" The clock resolution of the drop delay is the relevant issue here. In the MoFlo, it is 1/16th of a drop interval and in other machines, 1/10th and as low as 1/4th . The sorter knows where the cell is placed after measurement, within the pertinent time resolution interval, 1/16th, 1/10th or 1/4th as the case may be. One 1/16th is better than 1/4th , naturellement! On MoFlo, a 1-2 mode of sorting will sort one drop 7/8th s of the time, but when the target cell is known to be positioned in the first or last 1/16th of the drop interval, a second drop is charged and sorted. A further decision is involved according to whether enrich or purify mode is involved. Enrich-mode ignores the contents of the adjacent drop, but purify-mode defers to the contents of the adjacent drops, according to its pass/fail contents. In other machines, the process is called upon more often than in MoFlo, so they have more rejections of cells as a result. Bottom line: get better drop delay resolution: 1/16th > 1/10th > 1/4th . I hope this helps. We can talk about this, OK? Pbob -----Original Message----- From: Joseph Webster [mailto:J.Webster@centenary.usyd.edu.AU] Sent: Tuesday, 9 March 1999 12:58 To: Cytometry Mailing List Subject: BD Sorter question Hi All, My head is not quite the right shape to get around some things... Can someone please explain the algorithm or logic of partial- drop sort decisions? A couple of people have tried, but I have not understood yet... One and three drop sort envelopes are understandable, but when I tell the FACStar Plus to sort a two drop or a one-and-a-half drop envelope, how does it choose which drops to collect? Does it change between modes? (C, R, Counter, Enrich..) Thanks, Joseph. -- Joseph Webster Flow Cytometry Facility Centenary Institute
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