The IUCr Newsletter is the web magazine of the International Union of Crystallography. Since 1993, the IUCr Newsletter has been published quarterly and distributed to over 13,000 crystallographers worldwide. In August 2018, it was transformed into a dynamic digital platform with a fresh new look. Its aim remains to bring together the crystallographic community.
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William L. Duax Patricia Potter Jane Griffin The IUCr Newsletter is distributed electronically to 13,000 crystallographers and other interested individuals in 102 countries. Articles from the Newsletter are also available on this web site by following the links on the left-hand side. Feature articles, meeting announcements and reports, information on research 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 Matters pertaining to advertisements should also be sent to the above address. Email address changes or corrections and requests to be added to the mailing list should be accomplished through the Subscribe and Unsubscribe hyperlinks above. Reuse permissions • The original article in which the material appeared is cited. • Copyright permission is indicated by the wording "Reproduced with permission of the International Union of Crystallography Newsletter". In electronic form, this acknowledgement must be visible at the same time as the reused materials, and must be hyperlinked to the IUCr Newsletter (http://www.iucr.org/news/newsletter). Please be sure to include the following information: • The title, author(s) and page extent of the article you wish to republish, or, in the case where you do not wish to reproduce the whole article, details of the section(s) to be reproduced. • The volume/issue number and year of publication in which the article appeared, and the page numbers of the article. • Details of the publication in which you wish to reprint the Newsletter material. • If the material is being edited or amended in any way, a copy of the final material as it will appear in your publication. • Contact details for yourself, including a postal address. |
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Annual Reports to the IUCr Executive Committee
The IUCr Newsletter (ISSN 1067-0696; coden IUC-NEB) is published quarterly (4x) by the International Union of Crystallography (IUCr Executive Secretary e-mail execsec@iucr.org). Members receive the IUCr Newsletter by virtue of country membership in the IUCr. Periodical postage rates paid at Buffalo, NY and additional mailing offices. POSTMASTER: Please send changes of address to IUCr Newsletter Editorial Office, c/o Hauptmann-Woodward Medical Research Institute, 700 Ellicott St. Buffalo, NY 14203 USA.
From 20 to 27 July 2022, the French Committee for Crystal Growth (CFCC-French Crystallography Association) and the European Network of Crystal Growth (ENCG) co-organized in Paris, France, the third edition of the European School of Crystal Growth (ESCG3, 20–23 July) and the seventh edition of the European Conference of Crystal Growth (ECCG7, 25–27 July). These joint events were organized in association with the International Organization of Crystal Growth (IOCG) and the French Crystallography Association (AFC), and with the financial support of the IUCr. The Deutsche Gesellschaft für Kristallwachstum und Kristallzüchtung (DGKK), IUCr Journals, CrystEngComm (RSC) and Crystals (MDPI) awarded seven prizes. ECCG7 was also sponsored by AMTS and ScIDre GmbH. Additionally, AFC and the German FAIRMat initiative (FAIR Data Infrastructure for Condensed-Matter Physics and the Chemical Physics of Solids) hosted a booth at ECCG7.
Four years ago in Varna, Bulgaria (ESCG2-ECCG6), the ENCG Council had come up with several specifications for the organization of the third edition of ESCG. Firstly, the school should last four days including a Saturday to broaden its scope and save participants travel expenses between the school and the conference. Secondly, all participants should be housed at the same location for both ESCG3 and ECCG7. Thirdly, there should be discussion time between participants and lecturers. Fourthly, there should be practical demonstrations on real growth reactors and crystal pulling machines. This last demand originated from the students participating in ESCG2. While the first specification was not difficult to satisfy, the second one turned out to be a real puzzle for the organizers. In the end, only one quarter of the participants were housed at FIAP Jean Monnet, an ESCG3 venue 25-min walk from the international student center. The third specification was of course met by leaving enough time for discussion at the end of each lecture but was also satisfied by having long lunch breaks with the lecturers in the restaurants of the Quartier Latin district.
ESCG3 gathered 41 participants, of which 32 also attended ECCG7, and 12 lecturers (Fig. 1), mostly coming from Europe [Belgium (1), France (10), Germany (9), Italy (3), Netherlands (5), Poland (3), Romania (1), Spain (1), Switzerland (1), UK (1)] but also from Kazakhstan (1), South Korea (3), Thailand (1) and USA (1). Of the participants, 31 were either PhD students or post-doctoral researchers. Fourteen young scientists were awarded an IUCr grant to attend the school. The lectures took place in a completely refurbished and upgraded (and air-cooled) amphitheater, just the day after a heatwave had hit Paris, which meant the participants could enjoy an 8 °C temperature drop upon starting the school.
![[Fig. 1]](https://www.iucr.org/__data/assets/image/0007/155275/1.jpg)
The international pedagogical committee worked out a broad four-day-long program (19 hours of lectures, Fig. 2), from theoretical physics of crystal growth to experimental biological crystallization, from nucleation to bulk crystal growth. All space and time scales of crystal growth phenomena were covered, in some way or another, experimentally and theoretically, not forgetting the modelling and numerical simulation approaches. Furthermore, small single crystals, bulk single crystals, eutectic composite materials, thin films and heterostructures … virtually all shapings were addressed. Cutting-edge in situ synchrotron X-ray radio- and topography techniques, which permit solidification interface morphological instabilities, dislocation formation and mobility, and dendrite formation to be followed ahead of the solidification interface, were also introduced. Thin-film characterizations that are closely related to their growth conditions and mechanisms were brilliantly exposed. An advanced introduction to nucleation, both classical and under microfluidic conditions, was delivered.
![[Fig. 2]](https://www.iucr.org/__data/assets/image/0008/155276/2.png)
In addition, laboratory visits and practical demonstrations on real pulling machines were organized (Figs. 3 and 4). The participants were distributed in eight groups in order to attend alternatively a total of six practical demonstrations (leading to a total amount of three hours for a given group) over three days. These practical demonstrations, on real pulling or deposition machines, including Czochralski growth, high-temperature solution growth, optical floating-zone growth, chemical vapor deposition (CVD), high-throughput membrane protein and cubic phase crystallization platforms, counterdiffusion/capillary and dialysis protein crystallization, were much appreciated by everyone, as the final roundtable discussion revealed. The commitment of the lecturers and practical demonstration chairs was total, and the participants were able to get all the lecture files, some simulation programs, many didactic videos and important textbooks at the end of the school.
![[Fig. 3]](https://www.iucr.org/__data/assets/image/0009/155277/3.png)
![[Fig. 4]](https://www.iucr.org/__data/assets/image/0010/155278/4.png)
For this seventh edition of ECCG, following the recommendations of the ENCG council and in synergy with both the international scientific and the program committees, the organizers had to implement a scientific program with a broader scope. Consequently, 14 sessions, 3 parallel sessions and double the number of plenary lectures were implemented. A particular effort was made to substantially increase the participation of early-career scientists in session invited lectures, oral communications and poster communications. Seven awards publicized worldwide were delivered. Moreover, the organizers publicly endorsed the IUCr GEDC Code of Conduct, which — among other things – requested that attention should be paid to gender balance and affiliation country balance in all organization and scientific aspects of the conference. Hence, a few days before the events started, the organizers published on the ESCG3–ECCG7 website detailed statistics about gender balance and affiliation country in ECCG7 international scientific and program committees composition, ESCG3 international pedagogical committee composition, ESCG3 lecturers list, ECCG7 session chairs composition, invited lectures (both plenary and session), oral communications and so on. Five of the 24 session invited lectures, as well as 32 of the 77 oral communications and 57% of the poster presentations were delivered by early-career scientists. Seventeen young scientists were awarded an IUCr grant to attend the conference, among which 13 had attended the school too (Fig. 5). Of the 17 IUCr grant awardees, 10 were women, and if we add ECCG6 and ECCG7 best poster and best oral communication awards, a total number of 5 women awarded over 11 prizes is reached.
![[Fig. 5 add]](https://www.iucr.org/__data/assets/image/0005/155318/5.png)
During the ECCG7 welcome address, Andrea Zappettini, the active ENCG coordinator, made an ENCG statement to condemn the war in Ukraine, and express ENCG solidarity with colleagues from the countries involved in the war and suffering from its consequences.
The ECCG7 gathered 223 participants (Fig. 6) from 34 countries around the world but with a main (quantitative) contribution from France, Germany, Poland, UK, Italy, the Netherlands and Switzerland.
![[Fig. 5]](https://www.iucr.org/__data/assets/image/0011/155279/5.jpg)
A total of 206 abstracts were submitted from 32 countries around the world with main (quantitative) contributions from France, Germany, Poland, Italy, USA, the Netherlands, Switzerland and UK. The most popular sessions in terms of abstract submissions were Fundamentals of Nucleation and Crystal Growth & Digitization in Crystal Growth; Surfaces, Interfaces, Epitaxial Growth & Growth at the Nanoscale (dedicated to the memory of Ivan V. Markov 1941–2022); Semiconductors; Optical Crystals; and Functional Crystals. The smaller Mineral Growth Processes session proved to be particularly vivid and outstanding, and the Crystallization of Organic Materials & Industrial Crystallization Process Engineering and Crystallization of Biological Molecules and/or in Biological Systems sessions also attracted a significant audience for the first time during an ECCG event. The program contained four invited plenary lectures, which were chosen according to the topical coverage of the conference, gender balance and affiliation country. All of them were absolutely brilliant and triggered interesting discussions. The first one, entitled Step-growth, impurities and mass transport: the surprising complexities revealed by simulation, introduced the full session on Fundamentals of Nucleation and Crystal Growth, and was delivered by James F. Lutsko (Université Libre de Bruxelles, Belgium). The second one, entitled Can the crystal structures of pharmaceuticals be predicted?, closely related to the session on Crystallization of Organic Materials & Industrial Crystallization Process Engineering, was delivered by Sarah (Sally) L. Price (FRS) (University College London, UK). The third one, entitled Recent advances in protein crystal growth, introduced the session on Crystallization of Biological Molecules and/or in Biological Systems, and was delivered by Simona Fermani (University of Bologna, Italy). The fourth one, entitled The physical chemistry of oxide molecular beam epitaxy, introduced the session on Surfaces, Interfaces, Epitaxial Growth, Thin Films & Growth at the Nanoscale, and was delivered by Oliver Bierwagen (Paul Drude Institute for Solid State Electronics, Berlin, Germany). In addition to these, 24 invited session lectures, 77 oral communications and 92 poster presentations distributed among the 14 session topics were delivered.
On 26 July, the participants enjoyed a gala dinner on the Seine riverboat Le Jean-Bruel. The weather and temperature were just perfect for a nice summer evening cruising past most of the well-known Paris monuments.
The following prizes were awarded (see Fig. 7).
| Prize | Recipient | Contribution | Presenter |
|---|---|---|---|
| DGKK best (ESCG3) student ECCG7 poster prize | Martina Cotti (Eindhoven University of Technology, the Netherlands) | Understanding the link in between hydration kinetics of CuSO4 powder and mm-tablets | Andreas Danilewsky |
| Acta Cryst. B Crystal growth section best oral communication awards for early-career scientists | Marloes Bisterwels (AMOLF, Amsterdam, the Netherlands) | Light-controlled nucleation and shaping of self-assembling nanocomposites | Geetha Balakrishnan, Chair, IUCr Commission on Crystal Growth and Characterization of Materials |
| Adrienn Maria Szucs (Trinity College Dublin, Ireland) | Crystallization pathways towards bastnäsite: the role of dolomite and aragonite in the formation of rare earth carbonates | ||
| CrystEngComm best poster award | Ondřej Černohorský (Institute of Photonics and Electronics, Czech Academy of Sciences, Prague, Czech Republic) | Chemical calculations in modelling of low-temperature growth of ZnO nanowires | Andrea Zappettini |
| CrystEngComm best oral communication award | Yvonne Tomm (Helmholtz-Zentrum Berlin für Materialien und Energie, Germany) | The same but different: Single Crystals of Quaternary Adamantines by Chemical Vapor Transport | Andrea Zappettini |
| Crystals best oral communication prize for an early-career scientist | Merve Kabukcuoğlu [Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany] | Evolution of Dislocations in GaAs Wafers under Processing relevant Conditions Studied by 2D and 3D X-ray Diffraction Imaging | Andrea Zappettini |
| Crystals best oral communication prize for a senior scientist | Frédéric Leroy (Aix-Marseille Université, France) | Ferroelectric nanodomains in epitaxial GeTe thin films | Andrea Zappettini |
![[Fig. 6]](https://www.iucr.org/__data/assets/image/0003/155280/6.png)
Finally, the ENCG Council met on 26 July and decided that the 4th ESCG and 8th ECCG events would be organized in Warsaw, Poland, in June or July 2024. It also elected its new Executive Committee: Thomas Schröder (Germany, ENCG coordinator), Linda Pastero (Italy, scientific secretary), Mike Leszczynski (Poland, ECCG8 chair) and Matias Velazquez (France, ECCG7 chair). The whole Council thanked Andrea Zappettini, Florinda Costa and Bogdan Ranguelov for serving on the Executive Committee, and Daniel Vizman for his support as ENCG webmaster.
In the last six months I have done a lot of things we were not encouraged to do at the height of pandemic.
I was able to attend IN PERSON two IUCr Finance Committee meetings and one IUCr Executive Committee meeting as well as two — very well organized — Regional Associate meetings, both in amazingly beautiful locations: ACA2022 in Portland, OR, USA (hybrid meeting, 480 in-person and 83 online participants, organized by Brandon Mercado, S. Powell, Anna Gardberg and Carla Slebodnick) and ECM33 in Versailles, France (about 900 participants, chaired by Sylvain Ravy, Andy Thompson and Jean-Paul Itié).
![[Fig. 1]](https://www.iucr.org/__data/assets/image/0010/155269/Portland.png)
I took part in the 7th European Conference on Crystal Growth (ECCG7), professionally organized by Matias Velazquez in Paris, France.
![[Fig. 2]](https://www.iucr.org/__data/assets/image/0009/155268/Paris.png)
I also participated in the recent IUCr Journals Management Board meeting (by Zoom). I was impressed by the huge amount of innovative work being done for the IUCr Journals under the leadership of Andrew Allen and Peter Strickland.
I met a lot of cool people with crystallography at heart: researchers, students, young scientists, volunteers, our staff — I mean I met many of you.
And — as usual — I am full of admiration for the great science you are all doing and for the innovative ways you are sharing your knowledge. Sharing with your peers, students and colleagues — on site and in other countries. I feel a lot of enthusiasm; I hope it will translate into many successful publications — contributing to many successful careers — not only in crystallography but also in the very diversified area of structural sciences.
We are just coming out of the pandemic and are still in the shadow of the devastating war in Ukraina but please realize the following:
Now is the time to strengthen collaboration among different countries and institutions.
Now is the time to enlighten many of our colleagues (proud physicists, chemists, biochemists and engineers) that their research is based on an appropriate understanding of (crystallographic) structure of any material they are working on.
Now is the time to organize a School or a Workshop. The Executive Committee of the IUCr has decided to rename the Calendar Committee (the proper name was Sub-committee on the Union Calendar) to Meeting Support Committee (MSC). I assume that this is a good decision as the new name better reflects what we are doing. Here I would like to thank Graciela Díaz de Delgado and the whole Calendar Committee team for the work well done in a very difficult time. At the same time I welcome Manfred Weiss as the new MSC Chair.
Now is the time to persuade your student to sign up for an (IUCr-supported) specific School or Workshop and to enrol in the World Directory of Crystallographers.
Now is the time to register for the Melbourne Congress, plan your contribution, check the program and decide how you want to participate.
Now is the time to spread our wings and encourage African researchers to continue developing research of their own. I admire the tireless work that Claude Lecomte, Michele Zema, Susan Bourne, JuanMa García-Ruiz, Yuki Kimura, Dave Billing and many others are doing in Africa. The African Crystallographic Association (AfCA), under the leadership of Delia Haynes, is expected to join the IUCr as a Regional Associate as soon as in Melbourne.
Now is also the time to engage with a science teacher in your local high school to take part in a local crystal growth competition (see here for an example recently reported in the IUCr Newsletter) — or any other of your favourite scientific activities.
I sincerely hope that you nominated a colleague or student for one of the IUCr Prizes (as when this Newsletter is published the deadline will have already passed). You can still make up your mind and think about a worthy candidate for the future.
We are the IUCr. We create and nourish global partnerships for developing structural science. We invent tools that other scientists are using. Our Journals and International Tables provide unparalleled expertise for a diverse approach to structural science. Our colleagues and partners build sophisticated equipment that — with a push of a button — solves difficult structures. And — with our Schools and Workshops — we create a community that understands that plenty of creativity and knowledge is needed to connect this “difficult to solve structure” with a real-world challenge: a new virus, a potential new drug, an efficient battery material or a low-cost, easily disposable food container.
And now is our time to do it all.
The three main macromolecular structure determination techniques are different enough to hold separate congresses and reunions, but there is one topic that connects them like no other: everyone wants to build the best possible atomic model. The 2020 CCP4 Study Weekend, held 7–9 January 2020 in the East Midlands Conference Centre (Nottingham, UK) while COVID-19 was still an outbreak on the other side of the globe, revisited this topic with integrative spirit.
For the first time ever, the meeting opened with a tag-team talk. Eleanor Dodson and Helen Saibil gave a historic perspective and introduced the particularities of model building in macromolecular X-ray crystallography and electron cryo-microscopy (cryo-EM), respectively. The meeting, cross-discipline by design, continued with a session on automated model building, opened by Tom Terwilliger, who discussed his methods for interpreting and improving cryo-EM maps automatically. The session continued with Isabel Usón, who is taking the mantle from George Sheldrick on the development of SHELXE and is adapting the software to trace models with maps calculated from electron diffraction data. Kevin Cowtan closed the session with a provocative talk on competitive versus collaborative science, based on their comparison of model building packages, presented in this special issue.
Once a model is obtained, it is time for real or reciprocal space refinement, hence our next session covered several methods for model correction and improvement. Garib Murshudov compared the particularities of X-ray crystallography and cryo-EM maps, laying the foundation for the next talk by Dorothee Liebschner, who discussed methods for automatic refinement of models in cryo-EM maps. Ana Casañal and Tristan Croll presented the latest improvements in real-space refinement in the Coot and ISOLDE software respectively, with Hamish Todd taking 3D model building to the next level through an exploration of the possibilities and limitations of virtual reality (VR) hardware for interactive model building.
While building a protein can be done fully automatically in an ever growing number of cases, identifying and building ligands is comparatively still a bottleneck due to the absence of a reference sequence, generally poorer density, the potential for multiple binding modes, or the very human self-deception in cases where there is no binding. Mihaela Atanasova discussed the York methods for carbohydrate model building, refinement, validation and analysis. Antonio Rosato covered metals, their coordination and representation in the MetalPDB database. Robert Nicholls offered solutions to the challenges posed by the building and refinement of covalently attached ligands and modifications, such as enzyme–substrate intermediates or protein glycosylation, respectively. Rachael Skyner presented the Fragalysis open source software, which allows the user to closely inspect numerous structures of protein–ligand complexes, all stored in the cloud and represented in a web browser. Dinner and the traditional ceilidh followed, paving the way for one of the last traditional social occasions in two years, as the 2021 and 2022 Study Weekends were remote-only events due to the COVID-19 pandemic.
The second day began with a session on low-resolution model building, led by Agnel Joseph who discussed flexible fitting and other tools in Flex-EM. Valeriy Titarenko presented methods for the identification of fragments in low-resolution cryo-EM reconstructions, adapting functions traditionally used in crystallographic molecular replacement. Helen Ginn introduced the Vagabond refinement software, where molecules are refined in torsion angular space. Sarah Harris explained how molecular dynamics can help even in projects where large molecular size can be a problem.
The next two sessions covered protocols and tools to use whenever a model is nearing deposition: validation, analysis and representation were brought into the foreground. Wah Chiu presented the results from the EM validation challenge; while most tools for model validation are easily transplantable from X-ray crystallography, certain problems are particular to EM and need dealing with as the average resolution of EM structures keeps improving. John Berrisford gave an overview of the tools and procedures associated with protein structure deposition in the Protein Data Bank in Europe and beyond – John was also a driving force behind the deposition tools in both CCP4i2 and CCP4 Cloud interfaces. Jiří Černý discussed methods for the validation of nucleic acid structures which, very much like saccharides in general, are of paramount importance to biological structures but have been left behind in method development in favour of a protein-centric perspective. Rafiga Masmaliyeva presented toBvalid, a tool for the analysis and validation of temperature factors. In the next session, but largely under the same topic, Anastassis Perrakis gave an overview of the validation and model improvement services in PDB-REDO. Marc Baaden showcased his software for the representation and analysis of macromolecules in VR in another example of gaming technology aiding scientists. David Sehnal concluded the session offering an overview of Mol*, the default molecular webviewer used by the PDB websites.
The meeting concluded with a mesmerizing talk by Jeroen Claus of Phospho Ltd, who demonstrated the application of industry-standard 3D modelling tools to the high-end visualization of macromolecular atomic structures.
The cover competition, which ran for the first time in the 2020 Study Weekend, produced a number of high-quality submissions. The winner of the contest, Marco Salamina’s ‘Structural Biology: the lost structure’, is showcased on the cover of both the virtual and printed editions, as well as the graphical abstract for this introduction.
We are grateful to CCP4 and its people for funding, championing and running the meeting. And, more than ever, we would like to acknowledge the work all the speakers put into their well crafted talks and carefully prepared papers for this proceedings issue, which is available as a virtual issue at https://journals.iucr.org/special_issues/2020/CCP42020/, and is now complete after a two-year winter.
This article was originally published in Acta Cryst. (2022). D78, 1192–1193.
The 10th Zürich School of Crystallography (19–30 June 2022) was held as usual in the Department of Chemistry at the University of Zürich (UZH), Switzerland. The 20 participants (11 female) comprised one MSc and 17 PhD students, one postdoc and one research associate. They came from 14 countries: Belgium, Croatia, Finland, Germany, Greece, Italy, Morocco, Norway, Poland, Slovakia, Slovenia, Sweden, Switzerland and Zimbabwe.
![[Fig. 1]](https://www.iucr.org/__data/assets/image/0008/155285/ZSC-2022_group_photo.png)
The central goal of the School is to equip each participant with enough knowledge of the theory and practice of X-ray diffraction and single-crystal small-molecule structure determination so that they can competently determine their own structures when they return to their home laboratory. The daily schedule is a blend of lectures, exercises and practical work, including the opportunity to gain experience at one of the five diffractometers we have available, which include dual-source Rigaku Oxford Diffraction Synergy and Supernova instruments as well as a Bruker Venture D8 diffractometer. As usual, we had our very popular 2:1 student–tutor ratio. Lively discussions between the participants and tutors also took place outside the formal class times.
All of the participants were very engaged and enthusiastic throughout the School. The levels of experience of the participants were varied, but all came away having learnt something new and feeling better equipped to tackle their own structure determinations. Many new friendships were forged and the group was very cohesive. On the sixth day, the going got a bit tough because of a COVID-19 outbreak; three participants and three tutors tested positive and had to isolate. This necessitated implementation of hybrid sessions so that those isolating could still follow the lectures via Zoom. For the computer-based practical work this group could form their own little school in the garden of the hotel (see group photo). We are most grateful for everybody’s untiring patience and willingness to pitch in and help with other organisational matters, such as delivering meals to those isolating in the hotel. The entire group handled the problems with a fantastic team spirit.
For teaching the concepts of symmetry, in addition to online materials, we broke into small groups and used wooden and plastic models representing all point groups. The ability to hold and tumble such models helped the participants to acquire the concepts more easily. It was also great fun watching the participants cutting their apples in the "La coupe du roi" exercise to demonstrate stereochemistry and chirality.
![[Fig. 2]](https://www.iucr.org/__data/assets/image/0009/155286/Fig.-2.png)
As an introduction to structure solution and refinement, the participants worked on several example structures of varying degrees of difficulty and with different challenges. They were designed to allow the participants to see into the black box and learn about the actual procedures going on when various buttons are clicked in the software and to interpret whether or not appropriate results are obtained. Each participant then works on the data set collected from one of their own crystalline samples. We used the OLEX2 software once again for most of the structure refinement work. The ease of use of OLEX2 and the extensive range of tools and graphics that it incorporates, such as those for modelling disorder, allowed us to demonstrate many aspects of structure solution and refinement in a didactically beneficial way.
![[Fig. 3]](https://www.iucr.org/__data/assets/image/0010/155287/Fig.-3.png)
We no longer have a fully equipped computer classroom readily available to us because the Department of Chemistry at UZH had moved to a new building. The participants therefore had to bring their own laptops and pre-install the software we planned to use. Mostly, this worked well, with only a couple of issues, usually related to an institution-supplied loaner laptop being locked against installation of new software.
Each day concluded with a short discussion where participants could express their feelings about their experience that day and we received some valuable feedback during these moments, allowing us to tweak some aspects of our sessions on the fly. On the final day, each participant sat a two-hour written exam either to obtain ECTS credit points or to self-test their knowledge.
The farewell banquet is an emotional time for everyone after making so many new friends. Each participant received a certificate, Swiss chocolate and a copy of the IUCr/OUP book Crystal Structure Refinement, A Crystallographer's Guide to SHELXL by Peter Müller.
![[Fig. 4]](https://www.iucr.org/__data/assets/image/0011/155288/Fig.-4.png)
The questionnaire filled in by the participants provided very positive feedback, although it was clear that many found the programme too dense and that more breaks and personal study time need to be scheduled into the programme. We are considering extending the school by at least one day in 2024, but are mindful of the fact that this adds to the accommodation costs and time commitment required of the tutors. The personal impressions of three participants are given below.
This School presented some new challenges for the organisers. The closure of the hotel next to the UZH campus meant we had to find new accommodation and evening meals at a reasonable price, which is not trivial; the hotel we chose added 30 minutes each way to the day's travel time. This contributed to some of the questionnaire remarks about needing more time in the programme. We will try to optimise this for the next School.
Although we had 39 applicants for the School, 19 of them withdrew their interest, mostly because they were unable to obtain funding for their travel and subsistence. This seems to be a common problem at the moment for similar schools, such as the European Crystallography School. Although we can distribute a few bursaries using funds kindly offered by some of our sponsors (IUCr, ECA, CCDC), we cannot usually cover the full subsistence costs, let alone travel expenses. Unfortunately, there is no student accommodation in Zurich, so we are reliant on hotels and they are not cheap in Switzerland. This limits the ability of some people to attend. For example, we had three applicants from Zimbabwe, but in the end only one very talented student could attend.
We gratefully acknowledge the generosity of the sponsors and supporters: Department of Chemistry at UZH, Swiss Society of Crystallography, CCDC, ECA, IUCr, Rigaku Oxford Diffraction, Dectris Ltd, Oxford Cryosystems, Bruker AXS, Anton Paar, Eldico Scientific, OUP, and Michael Wörle for taking many photographs, some of which are in this report.
![[Mateja]](https://www.iucr.org/__data/assets/image/0003/155289/Mateja-Pisai.jpg)
What an amazing experience it was to participate in the Zürich School of Crystallography 2022! Ten days of being fully devoted to crystallography flew by in a moment, but even in that relatively short time, a lot of knowledge was gained, whilst at the same time priceless memories were made.
I started my crystallographic journey a few years ago when I enrolled in PhD studies in a group where crystallography is a crucial research component. There I got familiar with some basic concepts, which allowed me to easily solve “routine” structures. However, during the research, I encountered a variety of advanced crystallographic problems, which required a proficient understanding of underlying principles in crystallography, especially X-ray diffraction. For those reasons, the Zürich School of Crystallography seemed like a perfect choice to help me obtain valuable knowledge that would allow me to overcome crystallographic obstacles. And that hypothesis proved to be true!
I must say that the organizers of the Zürich Crystallography School, Prof. Anthony Linden and Prof. Hans-Beat Bürgi, did a splendid job! Even before the school started, we were provided with thorough travel and school information and material well in advance, thus making our trip to Zürich and preparations for the school much easier. During the whole school, they carefully listened to participants’ impressions, wishes and needs, to determine if any improvements were needed, and to make us all satisfied with the school, thus ensuring that each one of us gets the most out of it, which is really impressive. They ensured that everything went smoothly, and handled every unexpected situation promptly and effectively.
The school program was quite intense but, in my opinion, very well structured, with a good ratio of theory to practice. The first two days consisted mostly of lectures, sequentially building up from basic concepts to more advanced topics. The lectures were followed by practical sessions in groups of two or five students per tutor. I especially liked this aspect of the school, where we had a chance to discuss and resolve specific problems in detail with our tutor and obtain a further explanation of troublesome topics concerning lectures or other subjects of interest. I was very pleased that a decent amount of time was dedicated to solving structures. Starting with several example structures, we learned to treat different kinds of problems, after which we were prepared to tackle our own structures. During that time, I learned quite a lot, not only how to solve, refine and finalize the structure, but even more importantly, how to think (critically) about every step of the process and result obtained. Our tutor showed us a whole new dimension of noticing the fine details, to which I usually would not devote as much attention as needed, and these proved to be extremely informative and useful.
Another aspect that made this school unique is that we had one whole afternoon dedicated to hands-on work on the diffractometer, again in small groups of two students per tutor. We went thoroughly through the whole procedure of collecting the X-ray diffraction data, from selecting the proper crystal to setting up the measurement, with all the tips and tricks for obtaining the best possible data for a given crystal. I found this experimental session very useful, as we got a chance to ask all the specific questions concerning our usual samples and troubleshoot problems that we frequently encounter.
In the last day of the school, we had an opportunity to test our knowledge by taking a two-hour written exam, which I found to be quite beneficial as I got a feeling about which parts I should revise, and work harder on. I can conclude that participating in this school resolved a lot of questions I had and it provided a comprehensive overview of theory and practice in crystallography. I learned a lot of new things and reviewed some known concepts from a different perspective, which consequently shed new light on the way I will work in the future.
I must express a great gratitude and admiration to all tutors of the Zürich School of Crystallography 2022. Their unpreceded engagement in passing the knowledge to us through lectures and practical sessions, with passion and clarity, made me forget about the morning sleepiness. Instead, each day I got up motivated and excited to come to the University and explore new avenues of crystallography. Their unquestionable experience and the diversity of the scientific specialties they brought to this school allowed us to get the answers to every question asked and helped us piece together some aspects of the intricate puzzle of crystallography. I find that their devotion to providing us with answers at every conceivable moment from breakfast till bedtime, readily, patiently and relentlessly, by always finding new and creative ways to explain crystallography and challenge our knowledge in a fun and innovative way, is the true treasure of this school and its ultimate value!
And in the end, I want to express a great gratitude to Prof. Hans-Beat Bürgi and Prof. Anthony Linden for providing me with the opportunity to participate in the Zürich School of Crystallography 2022. In addition to gaining invaluable crystallographic knowledge, I met a lot of wonderful people and made new friends. All the discussions and (crystallographic and non-crystallographic) adventures we had made this school an experience I will never forget.
This school was everything I hoped for and even more! I enjoyed every single moment of it, and I would do it all over again! Thank you so much!
![[Nitish]](https://www.iucr.org/__data/assets/image/0004/155290/Nitish-Kumar-Garg.jpg)
I recently participated in the Zürich School of Crystallography from 19 to 30 June 2022 and would like to share my experience about the school. I am a PhD student at Lund University and many of the previous PhD students from our lab, who had attended this school in past years, had recommended that I participate in this summer school. For me, who was a complete beginner in the field of crystallography, it was a wonderful opportunity to get to know about the field. I had so much to learn from the school starting from the basic theory behind diffraction of waves to finally being able to mount my own crystals on the diffractometer and further solving their structure using OLEX2. I felt that the course is a perfect combination of theory and practical knowledge and in such a short interval of time, the school managed to cover most of the relevant topics of the field. The fact that there is a tutor for every two students makes things easier to learn and it really helps a lot in understanding the concepts and to clear the doubts. The school had practical sessions with the tutors almost every day where we got to solve our own crystal structures and also deal with some practice structures using OLEX2, which helped me a lot in getting familiar with the software. I also felt that the tutors were really giving their best to make sure everyone gets the most out of the school and they were also available outside school hours for any help. Also, the course content and material given to us both before and during the course was quite helpful. I also want to mention that the school had such an excellent social environment among the students and the tutors, which is a very important part of learning and overall, I am really happy that I got the opportunity to participate in the school.
![[Pawel]](https://www.iucr.org/__data/assets/image/0005/155291/Pawel-Butkiewicz.png)
I became interested in crystallography during my undergraduate studies where I measured monocrystalline inorganic materials and tried to solve their structures. My knowledge, despite attending lectures on solid-state physics and studying the issues of X-ray diffraction by myself, still did not allow me to fully understand and interpret the results obtained during these experiments. I was still wondering to what extent my studies corresponded to reality and if at some point in the procedure I had not made a serious error or misconduct. As a PhD student, I found out about the Zürich School of Crystallography, and the description of the event matched what I wanted to learn. I just had to go there. I applied to the school and started fundraising. Thanks to the kindness of the director of my doctoral school, my supervisor and the ECA bursary, I secured the necessary amount.
The organizers made sure that we could fully focus on learning and talking to other participants — we were provided with accommodation and morning and evening meals, and during the breaks between lectures, we were offered coffee, tea and sweets. It is hard to imagine better learning conditions.
Step by step, we became familiar with one crystallographic question after another (starting with the question of what a crystal is, and ending with quantum crystallography) and then we performed exercises in groups of several people under the supervision and help of one of the tutors. The exercises allowed us to learn the material on an ongoing basis.
A few days after the beginning of the course, we were formed into groups of two students, and for the rest of the school, we learned to solve and refine structures together for several hours a day under the supervision of a permanent tutor.
Another element of the course, which was particularly valuable didactically, was the possibility of measuring and solving the structure of the crystal grown by hand. We were able to compare the experimental procedures and the resolution and refinement process performed by us and by the experts on the same sample, which was the best method of identifying the errors we were making.
The course ended with an exam, thanks to which we could check the extent to which we acquired the knowledge and skills passed on to us.
I learned the stages from the formation of crystals to the publication of data, I understood the concepts necessary to be a conscious crystallographer, I learned to use methods that were unknown to me, I got answers to questions that have been bothering me for years, I met wonderful people. It made my work even more interesting and gave impetus to the implementation of new research concepts. I would like to thank the organizers and lecturers of the Zürich School of Crystallography and the ECA organization as well as sponsors from my University for the opportunity to participate in the school, thanks to which I owe it all.
We are thrilled to announce that three world-leading experts in their field will headline IUCr 2023 in Melbourne: Professor Hideo Hosono from the Tokyo Institute of Technology, Japan; Dr Junko Yano from Lawrence Berkeley National Laboratory, CA, USA; and Professor Mark Spackman from the University of Western Australia, Perth, Australia.
Professor Hosono is renowned for his work on the creation of novel functional materials. Some of Hideo’s noteworthy achievements include the design of transparent oxide semiconductors such as indium gallium zinc oxide (IGZO) and their thin-film-transistor (TFT) applications for state-of-the-art displays (OLED TVs are driven by IGZO-TFTs), creation of room-temperature stable electrides and their application to catalysts for ammonia synthesis, and discovery of high-Tc iron-based superconductors. Hideo is an honorary and professor of Tokyo Institute of Technology and a group leader and distinguished fellow at the International Center for Materials Nanoarchitectonics (MANA) of the National Institute for Materials Science. He received a PhD in Applied Chemistry from Tokyo Metropolitan University in 1982, and became a professor of Tokyo Institute of Technology in 1999 via the Nagoya Institute of Technology and Institute for Molecular Science at Okazaki. He is a recipient of various honors including the Japan Prize, von Hippel Prize (MRS), J. McGroddy Prize (APS), Jan Raychman Prize (SID), Imperial Prize of the Japan Academy, Thomson Reuter Citation Laureate and a foreign fellow of the Royal Society.
Dr Yano’s research has focused on problems of importance to energy, especially renewable energy sources. Her group uses X-ray spectroscopy and crystallography to understand biological and inorganic systems. For example, her lab has explored how in photosynthesis, plants use light to split water using a catalytic Mn4Ca cluster, and converting light energy into chemical energy. Since the advent of X-ray free-electron lasers (XFELs), her group has been using these facilities to study the catalytic systems, under functional conditions at room temperature. These methods allow one to study structure–function relationships by following the reactions in real time and the effect of the environment of the protein on the active site. Junko is a member of the Liquid Sunlight Alliance (LiSA), where she studies artificial photosynthetic systems, combining her interests in natural photosynthesis/metalloenzymes with inorganic systems that can be used to engineer practical devices. Since 2015, Junko has held the position of Senior Scientist, and Division Deputy for Science (since 2020) in the Molecular Biophysics and Integrated Bioimaging Division at the Lawrence Berkeley National Laboratory, CA, USA.
Emeritus Professor Spackman is well known around the world for his development of tools and methods from computational chemistry to inform aspects of modern crystallography, especially intermolecular interactions and crystal packing. These research tools have been implemented in the CrystalExplorer software package, now used by thousands of students and researchers worldwide. Mark is an emeritus professor at the University of Western Australia (UWA) in Perth, where he received his PhD in 1980. Following postdoctoral stints with R. F. Stewart (Pittsburgh), E. N. Maslen (Perth) and B. M. Craven (Pittsburgh), and an academic appointment at the University of New England (NSW, Australia), he returned to UWA in 2004. In 2013 he was a joint recipient with Carlo Gatti (Milan) of the Gregori Aminoff Prize for Crystallography by the Royal Swedish Academy of Sciences and was awarded the Lawrence Bragg Medal of the Society of Crystallographers in Australia and New Zealand in 2017.
The confirmation of the three plenary speakers and a strong scientific program are sure to elevate IUCr 2023 to new heights.
With abstracts already being received, it is clear that IUCr 2023 will be the premier destination for researchers and industry partners in 2023.
The scientific work of the IUCr is conducted primarily through its Commissions. There are 22 individual Commissions and Committees that comprise groups of scientists representing the key areas of crystallography sciences including the following:
| Aperiodic Crystals | Inorganic and Mineral Structures |
| Biological Macromolecules | Magnetic Structures |
| Committee on Data | Mathematical and Theoretical Crystallography |
| Crystal Growth and Characterization of Materials | Neutron Scattering |
| Crystallographic Computing | NMR Crystallography and Related Methods |
| Crystallographic Teaching | Powder Diffraction |
| Crystallography in Art and Cultural Heritage | Quantum Crystallography |
| Crystallography of Materials | Small-Angle Scattering |
| Diffraction Microstructure Imaging | Structural Chemistry |
| Electron Crystallography | Synchrotron and XFEL Radiation |
| High Pressure | XAFS |
It is the strong desire of the organising committee to create an inclusive culture and diverse environment at IUCr 2023, which we believe starts with the formation of the academic program, and representatives from each of the Commissions above participated in the IUCr 2023 International Program Committee meeting in April 2022. We encourage you all to submit an abstract, share your knowledge and collaborate with the global crystallography community.
The Call for Abstracts is currently open until 21 November 2022, with early bird registration available up to 15 February 2023.
It was our privilege to be at ACA2022, the 72nd Annual Meeting of the American Crystallographic Association in Portland, OR, USA, the first face-to-face ACA meeting since the pandemic. The excitement and appetite for an IUCr Congress in Australia was palpable. We met over 500 crystallography friends, many of whom were first-time attendees and many of whom were just grateful for the opportunity to reunite. Daily prize draws were conducted, with the final draw being a complimentary registration to IUCr 2023. This ultimate prize was awarded to Samantha Hartanto from the University of California Davis. Thank you to the ACA for hosting us in Portland; what a fantastic city and what a terrific event.
![[Fig. 1]](https://www.iucr.org/__data/assets/image/0016/155212/IUCr2023_ACA2022.png)
IUCr 2023 also felt very welcome at the 33rd European Crystallographic Meeting (ECM33) in Versailles, France, and we sincerely appreciate the efforts of the organisers. We had a wonderful and productive time. The start of ECM33 was directly aligned with the launch of the IUCr 2023 Call for abstracts announcement. Our team met over 350 attendees from across Europe and for one of them, the meeting proved extra worthwhile. Congratulations go to Jake Weatherston from Newcastle University, UK, the winner of the complimentary registration to IUCr 2023. The IUCr 2023 stand was enthusiastically depleted of all ‘I love Melbourne’ koalas, Melbourne-inspired keep-cups and the rare packets of Tim Tams.
![[Fig. 2]](https://www.iucr.org/__data/assets/image/0006/155229/IUCr2023_ECM33.png)
The next stop for the Melbourne team will be the 17th International Conference of the Asian Crystallographic Association in Jeju, Korea.
Since our last communication, Rigaku has been confirmed as a Diamond Sponsor for the Melbourne Congress in 2023, joining Bruker and Eldico. There will be many ways for our sponsors and exhibitors to connect with the IUCr community. Our focus is on elevating the delegate experience through the sponsorship of our wellness zones, childcare programs, juice bars and – of course – coffee carts!
The Congress team has been busily investigating a range of accommodation choices, from the best hotel facilities to backpacker hostels, with guaranteed room blocks for our IUCr delegates, including students and families.
If you have never been to Australia, it is worthwhile knowing that we have no added taxation at the point of sale. The advertised price is the final price you will pay. We also don’t have bed tax here! You can book directly via the website at any time. Alternatively, reach out to our accommodation team if you have an enquiry. Australia’s tax-free shopping is called the Tourist Refund Scheme (TRS), which allows overseas visitors and Australian residents to claim a refund of the Goods and Services Tax (GST), so save your receipts and claim at the airport upon departure.
Donald L. D. Caspar (1928–2021), a pioneer in understanding virus structures, passed away recently [1]. In this note, we talk about his cooperation with Aaron Klug (1926–2018). We also mention the influence of the geodesic dome, designed by R. Buckminster Fuller (1895–1983), on the research of virus structures. In conclusion, we quote excerpts from our 1996 conversation with Caspar.
![[Figure1]](https://www.iucr.org/__data/assets/image/0008/155195/figure1.jpg)
Left: Donald L. D. Caspar (1996) in Tallahassee, FL, USA. Right: Aaron Klug with a spherical model (2000) in Cambridge, UK. Both photographs by the Hargittais.
Caspar was born in Ithaca, NY, USA. Already at the age of 10, he became acquainted with interesting science. Through his chemistry graduate student father, he met the renowned crystallographer Isidor Fankuchen, who told him about the tobacco mosaic virus (TMV). Caspar studied at Cornell University (BA in physics, 1950) and at Yale University (PhD in biophysics, 1955). His dissertation was on the radial structure of TMV. At Yale, the research was focused on radiation biology, and biological structures were investigated by destroying them with X-rays, protons and deuterons. However, he thought that using X-ray scattering may be more instructive, and he carried out small-angle X-ray diffraction on TMV. He produced the second isomorphous derivative of a biological structure after the isomorphous derivative of hemoglobin by Max Perutz [2].
In 1954, Caspar moved to the California Institute of Technology (Caltech). Formally, he was in Max Delbrück's laboratory but was involved mostly in X-ray crystallography with Linus Pauling. Caspar used to build models of nucleic acids and viruses with James D. Watson. Eventually, he joined the Children's Cancer Foundation at Harvard Medical School, where he built models of icosahedral viruses. He went to Cambridge, UK, in 1955.
It was about this time that Aaron Klug met Buckminster Fuller, who visited Birkbeck College of London University. Klug was also interested in virus structures and recognized that there was some relationship between Fuller's work on geodesic domes and virus structures. Klug was born in Lithuania, and his family moved to South Africa when he was two years old. He studied at the University of Witwatersrand in Johannesburg and at the University of Cape Town. He continued in Cambridge and earned his doctorate in 1952. He was at Birkbeck College between 1954 and 1961, and at the Medical Research Council (MRC) Laboratory of Molecular Biology from 1962 for the rest of his career. He was one of the most distinguished British scientists. He received the Nobel Prize in Chemistry in 1982 for electron crystallography and the determination of complex nucleic acid–protein biological structures. He received the Copley Medal of the Royal Society in 1985, was a member of the Order of Merit and President of the Royal Society (1996–2000).
Fuller made constructions from early childhood throughout his long life. He enrolled at Harvard University, but was a maverick and a rebel and never graduated. His main work was his two-volume Synergetics [3], in which he followed Aristotle's maxim, "The whole is more than the sum of parts." Fuller built his first geodesic dome in 1947; it was a re-invention because such domes had been built before, but his constructions became famous. In the wake of his activities, many companies built a large number of geodesic domes over the years. Synergetics contains many interesting ideas, and many of them appear to have been taken from others, but Fuller was known not to indicate sources or references and not to acknowledge the contributions of others. But he impacted the research directions even of genuine scientists, such as Caspar and Klug.
Klug chose to investigate spherical viruses when developing his own research project at Birkbeck College. There was a tradition of such studies at Birkbeck. J. Desmond Bernal and Harry Carlisle took the first X-ray pictures of spherical virus crystals in the late 1930s. Rosalind Franklin made important advances by solving the structure of the protein helix of the virus, without the RNA. When Caspar joined Birkbeck College, he and Klug teamed up and found crystals of viruses in the refrigerator [4, p. 315]. Caspar took the bushy stunt virus and Klug the turnip yellow mosaic virus.
In 1962, Caspar and Klug published their discovery of the icosahedral virus structures in a seminal paper [5]. They profusely thanked Fuller for the inspiration they received from his creations, and one of their illustrations was a Fuller geodesic dome. They noted that the resemblance of the geodesic domes to the virus structures attracted their attention. By the time Fuller visited Birkbeck, Caspar had returned to the United States, but Klug attended Fuller's presentations. They were not easy to absorb because Fuller spoke a peculiar language. Klug noted about one of Fuller's books that he was interested in reading, but he had to 'translate' Fuller's peculiar English into an English understood by everybody else. Klug referred to Fuller as "a Yankee inventor, practical, totally untheoretical" [4, p. 316].
![[Figure2]](https://www.iucr.org/__data/assets/image/0009/155196/figure2.png)
Left: R. Buckminster Fuller (1970) at Pacific High School, Saratoga, CA. Photograph by and courtesy of Lloyd Kahn. Reproduced with permission. Right: Section of Fuller's geodesic dome built for the 1967 Montreal Expo. Photograph by the Hargittais. One of the pentagons among the hexagons is highlighted.
Caspar and Klug introduced quasi-equivalence among the large number of identical protein subunits of the virus structure, and this light deviation, however, from perfect symmetry, raised eyebrows. In hindsight, we may consider this as a forerunner of what quasicrystals represent, certainly an extension of classical crystallography. When Caspar and Klug initially proposed quasi-equivalence in their description of virus structures, Klug remembered "Max Perutz said in an interview in Science in 1966 that Klug was telling us these 'most unlikely stories'" [4, pp. 316–317]. According to Klug, Perutz thought that the protein units could not adapt to their environments because they were rigid. Caspar and Klug built their ideas on the notion that proteins had flexibility. They stressed that the chemical structures did not have to satisfy the requirements of exact mathematical principles; instead, they had to satisfy the requirement of reaching a minimum energy configuration.
Caspar had two major appointments consecutively. Between 1972 and 1994, he was Professor of Physics and Research Professor of Structural Biology at the Rosenstiel Basic Medical Sciences Research Center, Brandeis University. He has been credited with coining the expression "structural biology". Then, he was Professor of Biology at the Institute of Molecular Biophysics, Florida State University in Tallahassee. It was there that we visited him in 1996 and recorded a long conversation with him. His activities crossed disciplinary lines between physics, chemistry and biology, and involved viruses, fullerenes and quasicrystals. We quote a few excerpts from our conversation [6]:
On fullerenes:
"Our theory for icosahedral virus design accounts well for the design of fullerenes. The basic geometry of hexamers and pentamers forming closed shells leads to icosahedral symmetry, which is the most regular way to do this."
On quasicrystals:
"Quasicrystals are more interesting than crystals in the traditional sense. In the quasicrystal the same atom may take different positions with equal probability. But even in a quasicrystal one can categorize the atomic motifs and their number is limited. These motifs with local pentagonal or icosahedral symmetry can be combined in many different ways to generate quasi-periodic lattices. The activation energy of switching from one arrangement to another though is probably very high. However, in the growth process, the different arrangements are of equal probability. Thus there is no way of predicting which way the atom is going to go when the atoms are assembling."
On the general versus the individual:
"In physics, the greatest concern is in finding the underlying, unifying principle: abstracting out all the individuality, the differences among all sorts of systems to come down to some basic core. When I started in biology, I had a feeling that the use of such an approach would be constructive in understanding biological organization. Today, I think it is only a crude first step. Maybe we do find some generalization that is helpful for our comparing and categorizing of different systems, for example, the structural organization of different viruses. Almost all isomeric virus particles have icosahedral symmetry. But when we come down to such a core, we realize that what appears interesting in biology is not the underlying principle but the individual properties. … The uniqueness of the individual may not exemplify the properties of the group. There is some paradox here, and this makes biology so fascinating."
[1] Hargittai, I. (2022). "Donald D. L. Caspar (1927–2021) – pioneer of virus structures." Struct. Chem. 33, 993–995.
[2] Hargittai, I. (2022). "On the origins of isomorphous replacement in protein crystallography." Struct. Chem. 33, 635–639.
[3] Fuller, B. R. (1975). Synergetics: Explorations in the Geometry of Thinking. New York: Macmillan.
[4] Hargittai, I. (2002). Candid Science II: Conversations with Famous Biomedical Scientists, edited by M. Hargittai, ch. 20, "Aaron Klug", pp. 306–329. London: Imperial College Press.
[6] Hargittai, I. & Hargittai, M. Unpublished conversation with Donald L. D. Caspar, 28 November 1996, at the Institute of Molecular Biophysics, Florida State University, Tallahassee. Other excerpts from this conversation have appeared in Hargittai, I. & Hargittai, M. (2000). In Our Own Image: Personal Symmetry in Discovery, pp. 11, 56–57, 92–93, 96, 177. New York: Kluwer/Plenum.
Istvan Hargittai and Magdolna Hargittai are at Budapest University of Technology and Economics, Hungary.
This summer has been sweltering here in the UK, sometimes making it difficult to concentrate on work. Climate change? Probably, and this holds a warning to us all for the future. So what do we have in this issue of the IUCr Newsletter?
Now, as scientists, we expect to announce our discoveries to the rest of the world through publishing in legitimate science journals. We normally expect that papers that appear in journals and have been properly refereed can be trusted to be written in good faith so they can be treated as reliable. That, however, is an ideal, which sometimes is open to deception, and untrustworthy publications do appear from time to time that pollute the scientific literature. This is despite the fact that reputable journals, such as our IUCr journals, go to enormous efforts to maintain standards.
In recent years, there has been a growth in suspect articles being published. Sometimes this is simply a matter of incompetence of the authors, and referees have not spotted the errors. Referees are only human, aren’t they? But sometimes, there is a more malign reason. The pressures to publish as many papers as possible to gain job promotion or personal recognition are largely responsible for this. In April of this year, a paper appeared in which evidence of the existence was provided of a so-called “paper mill”, designed to create hundreds of fake manuscripts. You can read the original report here. Such material is challenging to track down especially as the articles often appear in many different journals. The publication of such dubious material has even affected the Cambridge Structural Database, where 992 recent crystal structure papers have been found across several journals, raising suspicions of “paper mill” activity. Fortunately, the CSD has excellent ways to detect them for the most part, but of course, one can never be certain that some may have crept through. I also recall that Armel Le Bail has been particularly active in finding many suspicious examples (see, for example, his “crystallographic horrors” at http://cristal.org/CHM/CHM.html). It is worrying to see publications like this polluting the scientific literature. I, too, have seen, while refereeing, some examples of identical powder diffraction patterns that have been repeated elsewhere, even though the authors claim to be studying different materials. This is something that journal referees need to be aware of these days. A recent research report on paper mills from the Committee on Publication Ethics (COPE) & STM gives an idea of the wider problem.
On a lighter note, it is great to see the steady development of crystallography growing within the African continent. Owing to the work of crystallographers such as Claude Lecomte and the IUCr, it has been possible to establish a Senegalese Crystallography Association. This can only bode well for the development of our science in Africa. I am proud of the role played in this by the IUCr.
The meetings of the IUCr Regional Associates are always a highlight of the crystallographer's year, and in 2022 we are delighted to congratulate the European Crystallographic Association on the occasion of their 25th anniversary. For those of you wondering how come we've already reached the 33rd European Crystallographic Meeting (ECM33), it's because the ECA succeeded the European Crystallographic Committee (ECC), which was founded 50 years ago at the very first ECM. Read more in ECA Vice-President Arie van der Lee's article here. During the ECM33 Opening Ceremony, Co-Chair Sylvain Ravy related how the ECM33 logo was inspired by the gardens at the 17th century Château de Versailles, close to the meeting venue, and went on to describe the types of symmetry exhibited by some of the gardens' features (see slides below). The ECA’s prestigious Perutz Prize went to Bill Clegg from Newcastle University (UK), a well-deserved winner for his contributions to crystal structure solution.
![[Slides]](https://www.iucr.org/__data/assets/image/0010/155197/slides.png)
The 72nd ACA Annual Meeting also returned to an in-person gathering in 2022 and hosted sessions – some hybrid – in an expanded range of disciplines. Read a report here. The IUCr awarded poster prizes at both ACA2022 and ECM33; many congratulations to the winners (shown below)!
![[ACA ECA poster prizes]](https://www.iucr.org/__data/assets/image/0009/155178/ACA-ECA-poster-prizes.png)
We look forward to the 17th Conference of the Asian Crystallographic Association, taking place in Jeju, Republic of Korea, from 30 October to 2 November 2022, and the 5th Meeting of the Latin American Crystallographic Association, which will be hosted by San José in Costa Rica from 28 to 30 November 2022.
Once again, the Hargittais have written an interesting article for the Newsletter, this time on the life of Don Caspar regarding his collaboration with the Nobelist Aaron Klug in connection with geodesic domes towards understanding virus structures. I always enjoy reading their contributions to the Newsletter.
Finally, in the previous issue of the Newsletter, Maureen Julian wrote about her experiences in Kathleen Lonsdale’s laboratory in the 1960s. She asks if anyone else can recall those times to contact her at erie@vt.edu.
Powder X-ray diffraction (PXRD) is a powerful tool for solving microcrystalline powder structures. Writing in IUCrJ, Schlesinger et al. (2022) report intriguing results demonstrating that, in the case of poor-quality PXRD data, starting from one experimental pattern, we can obtain different structure solutions, all crystallochemically plausible and satisfying the reliability criteria currently adopted in the solution process. This unexpected situation suggests adopting a more critical attitude towards structure determination from powders.
Crystallographic study is the leading scientific approach for recovering unambiguously the arrangement of atoms in a crystalline system. In the case of a single crystal, the structure determination is rarely affected by errors because the quality of the experimental diffraction data is usually good. However, in the powder case, the structural study faces several, and often concurrent, problems due to peak overlap, background noise, preferred orientation, limited quantity, poor quality of diffraction data, etc. Nevertheless, structure solution from powders has registered an increasing success over the years (cf. Fig. 1). Thanks to valuable methodological advances and high-performance computational resources (David, 2019; Altomare et al., 2019; Černý et al., 2019; Gilmore et al., 2019), we are now able to quite easily solve small molecular structures, especially if Bragg peaks in the diffraction patterns are sharp and the background noise is low. In particular, global optimization (GO) methods have become very popular to the point that they are sometimes preferred to direct methods, even when the latter can be successfully applied. In addition to the determination of unit-cell parameters and space group, the solution process through GO methods requires comprehension of the expected molecular geometry. The GO methods randomly move a starting structure model around the cell, in accordance with the assumed symmetry, adjusting its position, orientation and conformation (degrees of freedom, DoF) with the aim of reaching the global minimum of a cost function (CF, based on agreement between the observed and calculated profiles) and providing the correct solution. The solution process is completed by Rietveld refinement, followed by a careful crystallochemical check of the structure solution. Validation with dispersion-corrected density functional theory (DFT-D) calculations is recommended (van de Streek & Neumann, 2014). Finally, the corresponding CIF (crystallographic information framework) file is submitted to a crystal structure database (cf. Fig. 1).
Schlesinger et al. focus their PXRD investigation on the unknown crystal structure of 4,11-difluoroquinacridone (C20H10N2O2F2, DFQ), a non-commercial organic pigment derivative of quinacridone. With a rigorous and deep analysis, they prove that the DFQ structure is ambiguously solved if the solution process is carried out by a GO method followed by Rietveld refinement. At the same time, they demonstrate that a suitable combination of complementary methods can overcome this ambiguity and move towards the correct solution.
The DFQ poor-quality experimental diffraction pattern, collected on a laboratory X-ray powder diffractometer, presents only a few sharp and some broad Bragg peaks with severe overlap. Owing to a low level of crystallinity, the inadequate quality of this pattern cannot be improved upon by using synchrotron radiation. As things stand, the determination of unit-cell parameters by the most widely used indexing software is unattainable and the structure solution of DFQ can be classified as challenging.
Schlesinger et al. try to solve the DFQ structure by using the GO-based computing program FIDEL-GO (Habermehl et al., 2022), which has been specifically developed for structure determination from unindexed data. The rationale of FIDEL-GO is the global fit between simulated and experimental powder data: about 21 million random starting structure models compatible with the expected molecular geometry, located in cells with random parameters and different space groups, are submitted to the optimization process; unit-cell parameters, molecular position and orientation, and selected internal DoF are fitted simultaneously to the powder pattern; a similarity measure based on cross-correlation functions allows the comparison of simulated and experimental data. An automatic Rietveld refinement, a DFT-D geometry optimization and a user-controlled Rietveld refinement complete the solution process.
Four crystallographically different solutions, all worthy of being published, are obtained thus making uncertain the principle of structure unambiguity: they are all chemically reasonable (check of molecular packing, intermolecular distances, short intermolecular contacts); they are all compatible with the experimental diffraction pattern, and they surprisingly end with acceptable low R-values from Rietveld refinements; they all pass the CheckCIF test with trivial alerts. From an extensive examination of topology and Rietveld fits, only a slight preference for two of the solutions comes to light. Which one of them is correct?
Examples of incorrect published structures and structure ambiguity from PXRD are reported in the literature, but Schlesinger and colleagues go beyond this and accomplish a comprehensive analysis of the four structure candidates. They accurately compare the candidates and disclose why they are all compatible with the same experimental profile. Moreover, they reveal structure disorder by inspecting peak broadening.
It is significant that the authors solve the crux of ambiguity with the aid of additional analyses: (a) intramolecular and intermolecular examination through extensive pair distribution function (PDF) refinements (Schlesinger et al., 2021) using synchrotron data collected at both room temperature and 173 K; (b) evaluation of colour; (c) lattice-energy minimizations using force fields (Dassault Systemes, 2008) by optimizing molecular geometry and lattice parameters; (d) lattice-energy minimizations by DFT-D (Neumann et al., 2008; Giannozzi et al., 2017) by optimizing atomic positions and lattice parameters and calculation of the root mean square Cartesian deviation (RMSCD) of non-hydrogen atoms (van de Streek & Neumann, 2010); (e) solid-state NMR study with measurements of 13C, 1H and 19F spectra.
Overall, this insightful study reveals that structures solved from limited-quality PXRD data can be questionable if not supported by a multi-methodological solution strategy, as well as providing the correct structure of DFQ. The authors interestingly demonstrate that the application of the PDF fit method for structure refinement is promising.
A reasonable question arises from this work: can the combination of methods applied by Schlesinger et al. be generalized? Does this combination remove ambiguity in other similar cases? The issue remains open.
The answer to the question in the title is yes, even in the case of low crystallinity, but a critical inspection of results must be carried out every time the solution process is executed by using methods based only on the best fitting of the experimental PXRD pattern.
Altomare, A., Cuocci, C., Moliterni, A., Rizzi, R. (2019). International Tables for Crystallography, Vol. H, Powder Diffraction, edited by C. J. Gilmore, J. A. Kaduk & H. Schenk, pp. 395–413. Chichester: John Wiley.
Černý, R., Favre-Nicolin, V. (2019). International Tables for Crystallography, Vol. H, Powder Diffraction, edited by C. J. Gilmore, J. A. Kaduk & H. Schenk, pp. 442–451. Chichester: John Wiley.
Dassault Systemes (2008). Materials Studio. Version 4.4. BIOVIA, San Diego, CA, USA.
David, W. I. F. (2019). International Tables for Crystallography, Vol. H, Powder Diffraction, edited by C. J. Gilmore, J. A. Kaduk & H. Schenk, pp. 414–432. Chichester: John Wiley.
Giannozzi, P., Andreussi, O., Brumme, T., Bunau, O., Buongiorno Nardelli, M., Calandra, M., Car, R., Cavazzoni, C., Ceresoli, D., Cococcioni, M., Colonna, N., Carnimeo, I., Dal Corso, A., de Gironcoli, S., Delugas, P., DiStasio, R. A. Jr, Ferretti, A., Floris, A., Fratesi, G., Fugallo, G., Gebauer, R., Gerstmann, U., Giustino, F., Gorni, T., Jia, J., Kawamura, M., Ko, H.-Y., Kokalj, A., Küçükbenli, E., Lazzeri, M., Marsili, M., Marzari, N., Mauri, F., Nguyen, N. L., Nguyen, H.-V., Otero-de-la-Roza, A., Paulatto, L., Poncé, S., Rocca, D., Sabatini, R., Santra, B., Schlipf, M., Seitsonen, A. P., Smogunov, A., Timrov, I., Thonhauser, T., Umari, P., Vast, N., Wu, X. & Baroni, S. (2017). J. Phys. Condens. Matter, 29, 465901.
Gilmore, C. J., Kaduk, J. A., Schenk, H. (2019). International Tables for Crystallography, Vol. H, Powder Diffraction, edited by C. J. Gilmore, J. A. Kaduk & H. Schenk, pp. 698–715. Chichester: John Wiley.
Habermehl, S., Schlesinger, C. & Schmidt, M. U. (2022). Acta Cryst. B78, 195–213.
Neumann, M. A., Leusen, F. J. J. & Kendrick, J. (2008). Angew. Chem. 120, 2461–2464.
Schlesinger, C., Habermehl, S. & Prill, D. (2021). J. Appl. Cryst. 54, 776–786.
Streek, J. van de & Neumann, M. A. (2010). Acta Cryst. B66, 544–558.
Streek, J. van de & Neumann, M. A. (2014). Acta Cryst. B70, 1020–1032.
This paper was originally published in IUCrJ (2022). 9, 403–405.
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