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<DIV>RASMBers</DIV>
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<DIV>We too have seen this phenomena with a high MW protein that forms a sharp boundary early in the run. The high gradient deflects light out of the optical path. This has been described in print, I think in a German meeting proceedings. With the Model E high gradients during CsCl density gradient runs (the Meselson Stahl experiment) required refocusing of the optics to keep the light in the optical track. Not currently possible with the current XLA design.</DIV>
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<DIV><BR><BR>>>> "Norbert Muecke" <Norbert.Muecke@dkfz-heidelberg.de> 10/28/05 6:28 AM >>><BR></DIV>
<DIV style="COLOR: #000000">Hi,<BR>I have done some velocity runs at high protein conc. (up to 6g/l).<BR>A new peak within the boundary could be observed.<BR>I have attached the scans of three different concentrations.<BR>Absorbance was measured at 284nm.<BR>Any idea of how to explain that phenomena would be appreciated.<BR><BR>Best regards<BR>Norbert<BR><BR><BR>Division Biophysics of Macromolecules, B040<BR>German Cancer Research Center (DKFZ), TP3<BR>Im Neuenheimer Feld 580<BR>D-69120 Heidelberg, Germany<BR><BR></DIV></BODY></HTML>