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<div>Hi,</div>
<div id="AppleMailSignature"><br>
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<div id="AppleMailSignature">These are bright-field reflections arising from Bragg diffraction of the gold lattice in the nanogold. They should disappear at exact or Gaussian focus. But, you don't want to do that. The way to remove them should be to dial in
a smaller OL aperture that cuts off everything beyond 3Å resolution. <br>
<br>
Jaap
<div>----
<div>Jacob Brink <span style="font-size: 13pt;">Ph.D.</span></div>
<div><span style="font-size: 13pt;">TEM Product Manager Life Sciences</span></div>
<div><span style="font-size: 13pt;">JEOL USA, Inc., Peabody MA 01960</span></div>
<div><span style="font-size: 13pt;">(978) 317-9561</span></div>
<div><span style="font-size: 13pt;"><br>
</span></div>
<div>Sent from mobile device. Please excuse typos and this reply's brevity as I'm using all thumbs to type :-)</div>
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<div><br>
On Nov 6, 2017, at 4:18 PM, "<a href="mailto:vojta@strubi.ox.ac.uk">vojta@strubi.ox.ac.uk</a>" <<a href="mailto:vojta@strubi.ox.ac.uk">vojta@strubi.ox.ac.uk</a>> wrote:<br>
<br>
</div>
<blockquote type="cite">
<div><span>Hi Lars,</span><br>
<span></span><br>
<span>To my knowledge coloidal gold particles are almost always polycrystalline. At higher magnifications you will start to see lines corresponding to different spacing of the crystal lattices and if you crank the magnification all the way up to something
like 0.3 Apix you can see individual columns of atoms (attached below is an image of a wurtzite crystal I took on an F30 some time ago). The reflections you see move closer to each gold bead as you get nearer to focus which I think is an amazing example of
high resolution information being delocalised with defocus.</span><br>
<span></span><br>
<span>Only rarely do we see reflections like these in tomograms, I would also like to know what dethermines if they show up or not!</span><br>
<span></span><br>
<span>If you're interested in this topic I strongly recommend watching the supplemental videos in Lu et al. (2010,
<a href="https://www.nature.com/articles/nnano.2010.4">https://www.nature.com/articles/nnano.2010.4</a>) and you can also find plenty of publications on the structure of gold nanoparticles.</span><br>
<span></span><br>
<span>Best,</span><br>
<span></span><br>
<span>Vojta</span><br>
<span></span><br>
<span>Vojtěch Pražák</span><br>
<span>Graduate Student</span><br>
<span>Department of Structural Biology</span><br>
<span>The Wellcome Trust Centre for Human Genetics</span><br>
<span>Roosevelt Drive, Oxford, OX3 7BN UK</span><br>
<span>University of Oxford</span><br>
<span></span><br>
<span>Email: <a href="mailto:vojta@strubi.ox.ac.uk">vojta@strubi.ox.ac.uk</a></span><br>
<span>Web: <a href="https://www.strubi.ox.ac.uk/research/kay-grunewald">https://www.strubi.ox.ac.uk/research/kay-grunewald</a></span><br>
<span></span><br>
<span></span><br>
<span>---- Original message ----</span><br>
<blockquote type="cite"><span>Date: Mon, 6 Nov 2017 21:13:14 -0000</span><br>
</blockquote>
<blockquote type="cite"><span>From: "3dem" <<a href="mailto:3dem-bounces@ncmir.ucsd.edu">3dem-bounces@ncmir.ucsd.edu</a>> (on behalf of "Lars-Anders Carlson" <<a href="mailto:lars-anders.carlson@umu.se">lars-anders.carlson@umu.se</a>>)</span><br>
</blockquote>
<blockquote type="cite"><span>Subject: [3dem] reflections from gold fiducials </span><br>
</blockquote>
<blockquote type="cite"><span>To: <<a href="mailto:3dem@ncmir.ucsd.edu">3dem@ncmir.ucsd.edu</a>></span><br>
</blockquote>
<blockquote type="cite"><span></span><br>
</blockquote>
<blockquote type="cite"><span>Dear community,</span><br>
</blockquote>
<blockquote type="cite"><span>We encountered something during tilt series acquisition recently that I</span><br>
</blockquote>
<blockquote type="cite"><span>hadn't seen before: several 10 nm gold fiducials gave clear reflections,</span><br>
</blockquote>
<blockquote type="cite"><span>see attached image (compressed snapshot - it looks stronger in the</span><br>
</blockquote>
<blockquote type="cite"><span>original images).</span><br>
</blockquote>
<blockquote type="cite"><span></span><br>
</blockquote>
<blockquote type="cite"><span>The reflections were often symmetrically arranged around a fiducial and</span><br>
</blockquote>
<blockquote type="cite"><span>would then disappear at the next tilt ange. We used a 100 um objective</span><br>
</blockquote>
<blockquote type="cite"><span>aperture at a Krios@300kV. Admittedly I never worried about the</span><br>
</blockquote>
<blockquote type="cite"><span>crystalline arrangement of gold fiducials before, so I took some higher</span><br>
</blockquote>
<blockquote type="cite"><span>mag images of the fiducials, and some of them look mosaic, others more</span><br>
</blockquote>
<blockquote type="cite"><span>monocrystalline (see image), which could explain why some cause more</span><br>
</blockquote>
<blockquote type="cite"><span>reflections than others.</span><br>
</blockquote>
<blockquote type="cite"><span></span><br>
</blockquote>
<blockquote type="cite"><span>Is this something people have encountered before? Are some batches of</span><br>
</blockquote>
<blockquote type="cite"><span>fiducials better ordered than others at the atomic level? I'm curious to</span><br>
</blockquote>
<blockquote type="cite"><span>hear what people think of this since it fascinated me...</span><br>
</blockquote>
<blockquote type="cite"><span></span><br>
</blockquote>
<blockquote type="cite"><span>Cheers,</span><br>
</blockquote>
<blockquote type="cite"><span>Lars</span><br>
</blockquote>
<blockquote type="cite"><span></span><br>
</blockquote>
<blockquote type="cite"><span>-- </span><br>
</blockquote>
<blockquote type="cite"><span>Lars-Anders Carlson</span><br>
</blockquote>
<blockquote type="cite"><span>Assistant Professor</span><br>
</blockquote>
<blockquote type="cite"><span>Dept of Medical Biochemistry and Biophysics</span><br>
</blockquote>
<blockquote type="cite"><span>Wallenberg Centre for Molecular Medicine</span><br>
</blockquote>
<blockquote type="cite"><span>Umeå University</span><br>
</blockquote>
<blockquote type="cite"><span>901 87 Umeå, Sweden</span><br>
</blockquote>
<blockquote type="cite"><span></span><br>
</blockquote>
<blockquote type="cite"><span>lab website including OPEN POSITIONS:</span><br>
</blockquote>
<blockquote type="cite"><span><a href="http://www.carlsonlab.se/">http://www.carlsonlab.se/</a></span><br>
</blockquote>
<blockquote type="cite"><span>________________</span><br>
</blockquote>
<blockquote type="cite"><span>gold2.jpg (187k bytes)</span><br>
</blockquote>
<blockquote type="cite"><span>________________</span><br>
</blockquote>
<blockquote type="cite"><span>_______________________________________________</span><br>
</blockquote>
<blockquote type="cite"><span>3dem mailing list</span><br>
</blockquote>
<blockquote type="cite"><span><a href="mailto:3dem@ncmir.ucsd.edu">3dem@ncmir.ucsd.edu</a></span><br>
</blockquote>
<blockquote type="cite"><span><a href="https://mail.ncmir.ucsd.edu/mailman/listinfo/3dem">https://mail.ncmir.ucsd.edu/mailman/listinfo/3dem</a></span><br>
</blockquote>
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</blockquote>
<blockquote type="cite">
<div><Photo 01-06-2017, 16 50 14 (1).jpg></div>
</blockquote>
<blockquote type="cite">
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