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In case anyone is interested we've been able to do this for quite some time for TEM and SEM. One big breakthrough for EM lately was the ability to use direct de

by hyperion2010 12y ago

In case anyone is interested we've been able to do this for quite some time for TEM and SEM. One big breakthrough for EM lately was the ability to use direct detectors to look at frozen samples for tomography. With these techniques we can now reconstruct things like ribosomes all the way down to their atomic structure [1]. We used to have to use crystallography for this. 1. http://elifesciences.org/content/2/e00461 http://elifesciences.org/content/2/e00461

Osmium 12y ago
> In case anyone is interested we've been able to do this for quite some time for TEM and SEM. Well, not with SEM :) Do you have any more links to other significant cryo-EM papers btw? Looks incredibly fascinating. On the non-bio side, the recent major advances have been in aberration-correction technology. The big limiting factor in electron microscopy has been aberrations introduced by the electromagnetic lenses used to focus the beam (and the quality of the electron source itself). We're starting to get past that, which is good. The next step seems to be creating a lot more specialised electron microscopes, rather than just adding multiple detectors to a single microscope. To use an example, X-rays are also generated due to how the electron interacts with the sample, and if you detect the X-rays it can tell us what elements are present. Trouble is, X-rays are emitted in all directions, and in older microscopes there'd only be room for a single X-ray detector off to the side, because it also had a bunch of other detectors in there too, so it'd only capture a fraction of the X-rays emitted. So now people are realising that if they really want to push the limits of the technique, they have to create a electron microscope dedicated to, say, detecting these X-rays, so they can cram as many X-ray detectors around the sample as they can. This can make the difference between detecting an unambiguous signal to not detecting one at all, which is incredibly important when looking at, say, dopants or impurities in semiconductors which exist at very very low concentrations. This is just a single example, but there have been many many electron microscopy-based techniques that have been successfully validated in practice and can now be taken to the next level by building dedicated, specialised microscopes.
- hyperion2010 12y ago
  http://www.nature.com/ncomms/2014/140904/ncomms5808/full/ncomms5808.html http://www.nature.com/ncomms/2014/140904/ncomms5808/full/nco... is another example. IIRC there are people working on element detection with EELS.

Osmium 12y ago

> In case anyone is interested we've been able to do this for quite some time for TEM and SEM. Well, not with SEM :) Do you have any more links to other significant cryo-EM papers btw? Looks incredibly fascinating. On the non-bio side, the recent major advances have been in aberration-correction technology. The big limiting factor in electron microscopy has been aberrations introduced by the electromagnetic lenses used to focus the beam (and the quality of the electron source itself). We're starting to get past that, which is good. The next step seems to be creating a lot more specialised electron microscopes, rather than just adding multiple detectors to a single microscope. To use an example, X-rays are also generated due to how the electron interacts with the sample, and if you detect the X-rays it can tell us what elements are present. Trouble is, X-rays are emitted in all directions, and in older microscopes there'd only be room for a single X-ray detector off to the side, because it also had a bunch of other detectors in there too, so it'd only capture a fraction of the X-rays emitted. So now people are realising that if they really want to push the limits of the technique, they have to create a electron microscope dedicated to, say, detecting these X-rays, so they can cram as many X-ray detectors around the sample as they can. This can make the difference between detecting an unambiguous signal to not detecting one at all, which is incredibly important when looking at, say, dopants or impurities in semiconductors which exist at very very low concentrations. This is just a single example, but there have been many many electron microscopy-based techniques that have been successfully validated in practice and can now be taken to the next level by building dedicated, specialised microscopes.

hyperion2010 12y ago
http://www.nature.com/ncomms/2014/140904/ncomms5808/full/ncomms5808.html http://www.nature.com/ncomms/2014/140904/ncomms5808/full/nco... is another example. IIRC there are people working on element detection with EELS.