Hi Mike. It is great to have the Vice-President of the IUCr contributing again to the list, so I will have to be serious:-) The problem is, the list does sometimes become a little moribond without occasional provocation.
The current discussion touched on many interesting subjects - the poor quality of some published data, the interpretation of multi-phase patterns, the determination of symmetry and the interpretation of line-broadening, "serial crystallography" or single-crystal data from powders, and even non-crystal techniques such as single-molecule image reconstruction (XFEL) and single-particle cryo-EM. These new non-crystal techniques are indeed exciting, and related to much older tomography techniques as Jon implied, where large numbers of 2D projections can be reconstructed as a 3D image. A big difference is that with classical tomography you know the relative orientations, whereas with the xFEL and cryo-EM techniques you have to determine that for each molecule - you don't have a crystal to help you. These techniques are far from the expertise of most of us here, who indeed will still need crystals, usually as powders for inorganic materials. I too would like to see the list with more discussion of current techniques and publications, even if some of the comments appear provocative or even snarky. At least the members of this list have a certain expertise and sign their name to their comments, unlike the comments at the bottom of the Science article: http://news.sciencemag.org/biology/2015/05/electron-microscopes-close-imaging-individual-atoms BTW Mike, when I said that all structures are triclinic I was joking; actually most of them are monoclinic:-) Alan. ______________________________________________ * Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE * <alan.he...@neutronoptics.com> +33.476.98.41.68 http://www.NeutronOptics.com/hewat ______________________________________________
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