Welcome to the

International Union of Crystallography

The IUCr is an International Scientific Union. Its objectives are to promote international cooperation in crystallography and to contribute to all aspects of crystallography, to promote international publication of crystallographic research, to facilitate standardization of methods, units, nomenclatures and symbols, and to form a focus for the relations of crystallography to other sciences.

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In early May, during a Workshop on Crystallography and X-ray Diffraction, our Guatemalan colleagues founded the Guatemalan Association of Crystallography as a first step to becoming part of the IUCr. Sadly, those same colleagues are now struggling to deal with the after effects of the eruption of the Fuego volcano that claimed numerous lives. One way to provide financial support to the victims of the eruption would be via a site such as https://www.globalgiving.org/projects/guatemala-volcano-relief-fund/.
Posted 15 Jun 2018 

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Andrew Allen appointed as Editor-in-chief of IUCr Journals

[Andrew Allen]We are pleased to announce that Andrew Allen has been appointed as the Editor-in-chief of IUCr Journals. From mid-September 2018, Andrew will be replacing Samar Hasnain, who has completed his six-year term at the helm. We would like to take this opportunity to express our deep appreciation to Samar for his dedicated work and unstinting enthusiasm in developing IUCr Journals, increasing their impact factors, and for launching our flagship journal, IUCrJ.

Andrew is a long-time physicist working in materials science, neutron and X-ray scattering at the US Department of Commerce’s National Institute of Standards and Technology (NIST), Gaithersburg, MD, USA. His editorial connections with the IUCr extend back to 2002 when he first became a Co-editor of the Journal of Applied Crystallography (JAC). He became its Deputy Editor in 2011, and one of JAC’s Main Editors from 2014. During this time, he has acted as Guest Editor for several JAC special issues. Previously, he has also served on the Editorial Advisory Board of the Journal of Physics: Condensed Matter from 1991 to 1996. Andrew’s other main connections with the IUCr have centred on the IUCr Commission on Small-Angle Scattering, of which he has been a member or consultant since 2002, and Chair from 2011 to 2014, the triennial conferences on small-angle scattering (SAS), where he has been active on several organizational or advisory committees, including microsymposia organization and other SAS-related activities, at most triennial IUCr Congresses since 1996 (Seattle). He had already agreed to serve on the International Programme Committee for the IUCr2020 Congress in Prague. Previously, Andrew has served as Vice-Chair and Chair of the ACA’s Special Interest Group on SAS in 2000 and 2001.

Andrew Allen has indicated he feels greatly honoured to be appointed the next Editor-in-chief of IUCr Journals, and in particular to succeed John Helliwell, Gernot Kostorz and Samar Hasnain in this position, all of whom he has had the pleasure to work with during his time as Co-editor, Deputy Editor and Main Editor of JAC. As is well known, scientific journal publishing is facing a rapidly changing business environment, but Andrew looks forward to facing these challenges and opportunities over the coming months and years in his new role as Editor-in-chief.

Posted 18 Jul 2018 

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Mike Glazer appointed as Editor of the IUCr Newsletter

[Mike Glazer]We are very pleased to announce that Mike Glazer has been appointed as the Editor of the IUCr Newsletter, which will be relaunched in an entirely electronic format in summer 2018. Mike will be replacing Bill Duax, who retired last year after 25 years at the helm. We would like to take this opportunity to express our deep appreciation to Bill for his dedicated work and unstinting enthusiasm in disseminating news to the crystallographic community for a quarter of a century.

Mike is Emeritus Professor of Physics at the University of Oxford, UK, and Visiting Professor at the University of Warwick, UK. He has long been associated with the IUCr, most recently as Vice-President from 2014 to 2017 but also as Editor of the Journal of Applied Crystallography from 1990 to 1999 and as a member of many IUCr Commissions. His PhD research between 1965 and 1968 was under the supervision of Kathleen Lonsdale at University College London, UK, working on the crystallography of organic mixed crystals, and his research since then has mainly been in understanding the relationship between physical properties of crystals and their structures. He is perhaps best known for his classification system for tilted octahedra in perovskites.

Mike became interested in crystals at the age of seven, when he found his first natural mineral. This early interest remained with him and eventually took him into the field of crystallography. Since retirement, much of his time is now spent in transferring that enthusiasm to the public in the form of films, exhibitions, podcasts, interviews, lectures and demonstrations. On a recent visit to the IUCr offices in Chester, UK, where the Newsletter will be produced, Mike said that he was delighted to take on the role of Editor of the Newsletter, and looked forward to working with a team of five Regional Editors. "The Newsletter will be an important focus of the IUCr community," he commented, "and the new format will enable us to reach a much larger audience, including decision makers, informing them of the wonders and importance of Crystallography."

The Newsletter will continue to be the place to go for finding out news and developments in crystallography. Two issues are planned for 2018, with four issues per year to appear from 2019 onwards. Feature articles, information about research, meeting announcements and reports, or other items of potential interest to crystallographers may be submitted to the Editor at any time. Items will be selected for publication on the basis of suitability, content, style, timeliness and appeal. Please send contributions to newsletter@iucr.org.

Posted 05 Jul 2018 

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2017 IUCr impact factor results

alljournals2017_400pxThe 2017 impact factors have been released by Clarivate Analytics. We are pleased to announce that all IUCr Journals have increased their impact factors and that IUCr Journals now occupy the top four positions in the Crystallography category.

The impact factors of other journals also increased:

The Editor-in-chief of IUCr Journals, Professor Samar Hasnain commented:

"Each of our journals have made a significant improvement in the latest impact factor results. We thank our authors, reviewers, editors and co-editors for their commitment to ensuring that the best of structural science and underpinning technology and methods is reported in IUCr Journals. This is the first time that four of our journals concurrently have an impact factor above 6, and we look forward to building on this success."

Peter Strickland, Executive Managing Editor of IUCr Journals, noted:

"This is first time, since I started working for the IUCr some 30 years ago, that I can remember all of the journals increasing their impact factors in the same year."

For more details, see https://journals.iucr.org/services/impactfactors.html

Posted 26 Jun 2018 


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New algorithm enhances ptychographic image resolution

[Acta A cover]

Ptychographic X-ray imaging is used to characterize the structure and properties of matter and materials. While the method has been around for 50 years or so, wide use was at first hampered by the experimental process being slow and the computational processing of the data to produce a reconstructed image being expensive. But in recent years, advances in detectors and X-ray microscopes at light sources such as Lawrence Berkeley National Laboratory's Advanced Light Source have made it possible to measure a ptychographic data set in seconds. As a result, today ptychography is used in a range of scientific domains, including condensed-matter physics, cell biology and electronics.

Reconstructing ptychographic data sets can be a data-intensive challenge, as it involves solving a difficult phase-retrieval problem, calibrating optical elements and dealing with experimental outliers and 'noise'. To address this challenge, Berkeley Lab scientists developed SHARP (scalable heterogeneous adaptive real-time ptychography), which enables the reconstruction of millions of phases of ptychographic image data per second. Since being introduced in 2016, SHARP has had notable successes in the analysis of magnetic thin films, magnetozomes and three-dimensional battery materials.

Now members of the SHARP collaboration have developed a model that further enhances SHARP's reconstruction capabilities. The new algorithm, GDP-ADMM (gradient decomposition of the probe/alternating direction method of multipliers), is described in a recent article in Acta Crystallographica Section A [Chang et al. (2018) Acta Cryst. A74, 157-169] and was featured on the cover of the May issue. GDP-ADMM takes advantage of state-of-the-art mathematical aspects of phase retrieval, background-noise optimization and detector 'denoising', allowing SHARP to handle more light than before, enabling faster data acquisition and higher time resolution, and ultimately more scientific discoveries.

'The goal was to offer the ability to quickly discover interesting nanoparticles at full resolution by enabling rapid feedback from the microscopists at the beamlines,' said Stefano Marchesini, a staff scientist at Berkeley Lab and a co-author of the article. 'Even when the next-generation coherent light sources come online, we may be able to extend the X-ray energies that can be used in ptychography by using this model.'

Posted 25 Jun 2018

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Hydrophobic dipeptides: the final piece in the puzzle

The results from ab initio structure prediction programs have demonstrated that any organic molecule has the potential to interrelate with its siblings in a number of different ways, the observed crystal structure representing an energy minimum where the contributions from various types of intermolecular interactions have been carefully balanced. Systematic investigations of molecules that share one important moiety/feature provide valuable experimental data for the understanding of this balance and for rationalizing important trends, even among other sets of compounds. Amino acids constitute an attractive group for such a survey, with a common polar head and a variable side chain. Crystal structures of more than 120 regular, acyclic amino acids have been published in the past, meaning that the 20 proteinogenic amino acids represent but a minor fraction of the experimental material. If these amino acids are used, however, to construct dipeptides, they alone leave 20 x 20 = 400 different options. As of June 2018, crystal structures are only available for 104 of them.

[Hydrophobic dipeptides]Hydrophobic dipeptides is a subgroup of particular interest. These are based on combinations of the five non-polar amino acids alanine (Ala), valine (Val), isoleucine (Ile), leucine (Leu) and phenylalanine (Phe) only, meaning that hydrogen bonds are essentially limited to connecting the constant parts of the molecules, i.e. the peptide main chains. Accordingly, any change in crystal structure upon amino acid substitution is due to the side chain.

The crystal structure of Val-Leu acetonitrile solvate presented in Görbitz (2018). Acta Cryst. B74, 311-318 is the 25th and last missing piece in the 5 x 5 puzzle of hydrophobic dipeptide structures. This “completion event” is used here as an opportunity to review their crystal packing arrangements and hydrogen-bonding pattern preferences, the associated peptide conformations and the sometimes unexpected impact a seemingly modest amino acid substitution can have not only on the crystal structure but also on the propensity to include co-crystallized solvent molecules.

Carl Henrik Görbitz
Department of Chemistry, University of Oslo, Norway
Posted 19 Jun 2018