issue contents

ISSN: 2053-2733

May 2016 issue

Highlighted illustration

Cover illustration: In this issue the geometrical structural relations in axial symmetric proteins, B-DNA and icosahedral viruses are discussed in a series of three articles by the late Professor A. Janner (1928-2016). A coarse-grained modelling of the Pariacoto virus (PaV) using the projected points of a six-dimensional icosahedral lattice is shown [Janner, A. (2016). Acta Cryst. A72, 324-337].


scientific commentaries

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The representation of crystal structures by nets provides a useful framework for thinking about the design of new materials.

lead articles

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Algebraic and surgery techniques are applied to labelled quotient graphs of crystal structures to perform ring analysis and structural decomposition into subperiodic blocks.



research papers

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Four axial symmetric proteins are analysed on the basis of two lattices, the form lattice and the modelling lattice. The former is a sublattice of the latter.

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The positions of phosphorus in B-DNA are analysed by means of a five-dimensional lattice. This gives a one-to-one correspondence between atomic and indexed positions.

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The positions of the backbone atoms in an icosahedral virus are indexed using a six-dimensional icosahedral lattice and its projection on three-dimensional space.

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The dynamical theory for perfect crystals in the Laue case is reformulated using the Riemann surface.

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The results of computer simulations of the transmitted-beam intensity distribution are presented for the case of six-beam (000, 220, 242, 044, −224, −202) diffraction of X-rays in a perfect silicon crystal of thickness 1 mm. Both the plane-wave angular dependence and the six-beam section topographs are investigated.

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All homogeneous sphere packings were derived that refer to the invariant, univariant and bivariant lattice complexes with monoclinic symmetry.

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A general theoretical framework based on group–subgroup and group–supergroup relations is proposed to describe and derive interpenetrating nets.

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Labelled quotient graphs can be used to analyse vertex-connectivity in periodic graphs and assign a topological class to crystal structures.

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Generalization of the period doubling sequence to arbitrary dimension is developed.

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For ice nanotubes consisting of stacked n-membered rings, a new type of generalized symmetry and its violation are discussed.

short communications

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A Bayesian model which uses a Markov chain Monte Carlo algorithm has been developed to estimate structure-factor amplitude differences.

international union of crystallography

book reviews

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