<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 12 (filtered medium)"><style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Consolas;
panose-1:2 11 6 9 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri","sans-serif";
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Hi All –<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>We are observing what appear to be plateaus in the absorbance profile in both equilibrium and velocity runs. The plateaus are seen with different samples and different rotor speeds. Our current hypothesis is that the slit in front of the detector is sticking and releasing. It appears that these are lost steps as after the slit releases the exponential is shifted along the radial distance axis. Some representative data is attached showing different speeds and cells. The superimposed scans (cell 1 35K, & cell 1 44K) are scans recorded about 10 hours apart in time.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Is it reasonable to think that the slit is sticking? How can we diagnose and fix this problem?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Peter<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-size:10.5pt;font-family:Consolas'>Peter E. Prevelige Jr.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.5pt;font-family:Consolas'>Professor<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.5pt;font-family:Consolas'>Dept. of Microbiology, BBRB 416/6<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.5pt;font-family:Consolas'>Univ. of Alabama @ Birmingham<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.5pt;font-family:Consolas'>845 19th St. South<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.5pt;font-family:Consolas'>Birmingham AL. 35294-2170<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.5pt;font-family:Consolas'>Phone 205 975-5327<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.5pt;font-family:Consolas'>FAX 205 975-5479<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.5pt;font-family:Consolas'><a href="mailto:prevelig@uab.edu">prevelig@uab.edu</a><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.5pt;font-family:Consolas'><a href="http://www.microbio.uab.edu/faculty/prevelige/prevelige-p.htm">http://www.microbio.uab.edu/faculty/prevelige/prevelige-p.htm</a><o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>