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--></style><title>RE: [3DEM] A question about ice thickness of
cryo-EM</title></head><body>
<div>Hi Goubin,</div>
<div><br></div>
<div>We are using a 300kV unit when imaging through the 800nm thick
ice. As for 100kV, I really don't know how thick of ice you can
image through but as Bill pointed out, it is also a question of how
well you actually want to resolve the sample you are examining. </div>
<div><br></div>
<div>cheers,</div>
<div>Paul</div>
<div><br></div>
<div><br></div>
<div>At 1:16 PM -0600 2/17/05, Hu, Guobin wrote:</div>
<blockquote type="cite" cite><font face="Times New Roman"
size="+1">Dear Dr. Bill Tivol,</font></blockquote>
<blockquote type="cite" cite><font face="Times New Roman"
size="+1"> </font></blockquote>
<blockquote type="cite" cite><font face="Times New Roman"
size="+1">You are so right that the</font><font size="+1"> maximum ice
thickness for imaging depends on the HT of the scope. I sent a message
to Paul asking about the specific HT of 100 Kv. Hopefully He would
tell me a number. Of course, I'd be happier if our colleagues could
tell me the numbers not only of 100 Kv, but also of 200 Kv, 300 Kv and
400 Kv.</font></blockquote>
<blockquote type="cite" cite><font face="Times New Roman"
size="+1">Thanks!</font></blockquote>
<blockquote type="cite" cite><font face="Times New Roman"
size="+1"> </font></blockquote>
<blockquote type="cite" cite><font face="Times New Roman"
size="+1">Regards,</font></blockquote>
<blockquote type="cite" cite><font face="Times New Roman"
size="+1">Guobin</font></blockquote>
<blockquote type="cite" cite><font face="Times New Roman"
size="+1"> </font></blockquote>
<blockquote type="cite" cite><font face="Times New Roman"
size="+1"> </font></blockquote>
<blockquote type="cite" cite><font face="Times New Roman"
size="+1"> </font></blockquote>
<blockquote type="cite" cite><font face="Arial" size="-1"
color="#000080"> </font></blockquote>
<blockquote type="cite" cite><font face="Tahoma"
size="-1">-----Original Message-----<br>
<b>From:</b> owner-3dem@ncmir.ucsd.edu
[mailto:owner-3dem@ncmir.ucsd.edu]<b> On Behalf Of</b> Bill Tivol<br>
<b>Sent:</b> Thursday, February 17, 2005 1:01 PM<br>
<b>To:</b> 3dem@ucsd.edu</font></blockquote>
<blockquote type="cite" cite><font face="Tahoma"
size="-1"><b>Subject:</b> Re: [3DEM] A question about ice thickness of
cryo-EM</font></blockquote>
<blockquote type="cite" cite><font
face="Times New Roman"> </font></blockquote>
<blockquote type="cite" cite><font
face="Times New Roman"> </font></blockquote>
<blockquote type="cite" cite><font face="Times New Roman">On</font>
Feb 17, 2005, at 9:34 AM, Hu, Guobin wrote:<br>
<blockquote><font face="Times New Roman"> </font></blockquote>
<blockquote><font face="Times New Roman" size="+3"
color="#000080">Thanks for your information! You might have given me a
basic idea what the maximum of ice thickness could be. Actually
as indicated in my earliest message, I'm not trying to figure out
how thick the ice could be in any specific case. What I'm trying to
find out is an estimate of the maximum of ice thickness of cryo-EM
grids which is good enough for imaging. I wonder if anybody has ever
collected data with ice thicker than 800 nm.</font><br>
</blockquote>
<blockquote><font face="Times New Roman"> </font></blockquote>
<blockquote><font face="Times New Roman" size="+3"
color="#000080">Thanks for any further help!</font></blockquote>
<blockquote><br></blockquote>
<blockquote><font face="Times New Roman"> </font><br>
</blockquote>
</blockquote>
<blockquote type="cite" cite><font face="Times New Roman">Dear
Guobin,</font></blockquote>
<blockquote type="cite" cite><font face="Times New Roman">The maximum
ice thickness for imaging depends on the HT of your scope. We have
been imaging small whole cells at 300 kV, and we can do tomography on
cells that are a little smaller than 1 um. Of course, the ice may not
be that thick except in the immediate neighborhood of the cell, and
the resolution should improve for thinner ice, so the answer to
"Is the ice too thick for imaging?" is "It depends on
what you're trying to do and what equipment you have to do
it."</font></blockquote>
<blockquote type="cite" cite><font
face="Times New Roman">Yours,</font></blockquote>
<blockquote type="cite" cite><font face="Times New Roman">Bill Tivol,
PhD</font></blockquote>
<blockquote type="cite" cite><font face="Times New Roman">EM Scientist
and Manager</font></blockquote>
<blockquote type="cite" cite><font
face="Times New Roman">Cryo-Electron Microscopy
Facility</font></blockquote>
<blockquote type="cite" cite><font face="Times New Roman">Broad</font>
Center, Mail Code 114-96</blockquote>
<blockquote type="cite" cite><font face="Times New Roman">California
Institute of Technology</font></blockquote>
<blockquote type="cite" cite><font
face="Times New Roman">Pasadena</font> CA 91125</blockquote>
<blockquote type="cite" cite><font face="Times New Roman">(626)
395-8833</font></blockquote>
<blockquote type="cite" cite><font
face="Times New Roman">tivol@caltech.edu</font></blockquote>
<blockquote type="cite" cite>
<div><br></div>
<div><br></div>
<x-sigsep><pre>--
</pre></x-sigsep>
<div><font face="Courier New" size="+1" color="#000000">Paul
Chipman<br>
Electron Microscopy Facility Manager<br>
Dept. of Biology, Purdue University<br>
Lilly Hall, Rm. B216<br>
Phone: 765-494-1487<br>
Fax:765-496-1189</font></div>
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