Fundamental concepts of electron diffraction from crystals are introduced, based on the kinematical theory of diffraction. Characteristic features of electron diffraction, such as the Bragg reflection, crystal structure factor, atomic scattering factor, Laue function, Ewald construction, double diffraction effect etc, are described, in comparison with those of the X-ray diffraction.
Restructuring-type adsorption, in which substrate surface atoms are replaced, migrate and are rearranged, of alkali-metal atoms on low index surfaces of fcc metals is reviewed. In such adsorption the restructuring occurs at room or slightly higher temperatures, whereas overlayers are formed at lower temperatures. We classify eight composite surface-structures formed by the restructuring-type adsorption. Detailed structures and condition for the formation of each structure are described. In addition we include similar composite surface-structures formed by metal adsorption other than alkali-metals.
Escherichia coli 3-methyladenine DNA glycosylase II is a DNA repair enzyme that removes numerous alkylated bases from DNA. The three-dimensional structure, mutagenesis and model building studies suggest that the active site is located in a cleft between the two helical domains and that the enzyme flips the target base out of the DNA duplex into the active-site cleft. The structural similarity among a variety of DNA glycosylases shows the existence of a DNA glycosylase family, whose members recognize diverse sets of substrates.
It is hardly determined some details of the local atomic structures in multi-component non-crystalline systems by the ordinary x-ray diffraction method. I have applied the anomalous x-ray scattering (AXS) method to overcome these difficulties in the non-crystalline systems containing more than two elements. In the present paper, I will present my recent studies of the local atomic structures in a new type of amorphous alloys with an extremely wide super-cooled liquid region and of metallic complexes in Ni-Mo electroplating aqueous solutions. The usefulness of the AXS method in the studies of the non-crystalline materials will be demonstrated.
The purpose of this technical guide is to describe how dynamic light scattering (DLS) is employed to screen crystallization candidates. Many findings suggest that DLS is useful to evaluate crystallizability of macromolecules before any crystallization attempt. The description is started with an overview of the relation between the crystallizability of macromolecular solution and its monodispersity provided by the DLS measurement. A practical guide for the DLS experiment is also described briefly in the case of using a compact commercial product, Dyna-Pro form Protein Solutions, Inc. Finally, the case study we have done in some protein samples is presented.