Meeting report

XXIII IUCr Congress and General Assembly

Montreal, Canada, 5-12 August 2014

[Logo, Garcia-Ruiz, Janssen]

The time has come to bid a final adieu to IUCr 2014 and all it entailed. It is with great pride and satisfaction that your Canadian hosts reflect on the summer's events and their special contributions to the International Year of Crystallography (IYCr). And none more so than the Congress's co-chairs, Mirek Cygler and Albert Berghuis, who look forward to actively participating in the Hyderabad Congress, albeit in a slightly more relaxed role!

[Logo, Garcia-Ruiz, Janssen] Dan Schechtman
[Congress posters]
[Dancing]

In total, IUCr 2014 attracted 2425 participants representing 67 different countries. Over 2300 abstracts were submitted, of which over 700 were presented orally. And everyone was treated to an authentic taste of Montréal life by experiencing the interconnectivity of its academic and scientific communities with its food, jazz and circus culture.

The International Program Committee, chaired by Jim Britten, delivered a scientific program packed with highlights. In the Opening Ceremony Ewald Prize lecture on superspace crystallography, Ted Janssen (top photo, far right) made a difficult subject as clear as the Montreal sky. On the following day, Nobel Laureate Dan Shechtman delivered the story of the discovery and acceptance of quasicrystals with passion and humor. In other Plenary Lectures we learned of self-assembled nanostructured materials from Juan Manuel Garcia-Ruiz (top photo, center), David Bish took us to Mars for some powder diffraction studies, and John Miao showed us the power of coherent diffraction imaging and electron tomography.

A series of 36 Keynote lectures, including the Gjønnes Prize lectures from Michiyoshi Tanaka and John Steeds, brought us the most exciting crystallographic research from the leaders in our field. The IUCr Commissions were well represented in talks on everything from charge density to HIV; from Li batteries to the most powerful X-ray sources developed to date; from minerals to MOFs, from mathematics to magnetics; from carbon to quasicrystals, from a Voyage dans le cristal to membrane trafficking.

The program committee would like to thank the over 220 microsymposium co-chairs who gathered together almost 700 speakers and put excitement into every day of the meeting. Attendance was terrific, if not overwhelming at times. These topics attracted enough additional science to fill almost 1500 posters in sessions organized by Alba Guarné, with a number of poster prizes awarded by our generous sponsors. Again, all of the Commissions were well represented, with aperiodicity and electron diffraction showing a significant increase in interest over previous congresses.

The tradition of a Software Fayre was continued, organized by Martin Lutz, allowing software developers to demonstrate the latest improvements to their programs. To round out the scientific offerings, seven on-site workshops were offered covering software (USPEX, SHELX, OLEX2), aperiodic crystals, XAFS and XFEL sources. A Rietveld refinement workshop was offered by PANalytical, and two well attended post-Congress satellite workshops were held at McMaster U. examining magnetic symmetry/structures and advanced electron diffraction.

Complementing the core program were special exhibits celebrating IYCr, organized by Louise Dawe and Michele Zema. A series of public lectures were held, movies were shown and posters were displayed, all with the intent to raise awareness and interest in this multi-faceted discipline. A photo competition and a virtual reality experience helped to round out the offerings.

This event will surely live on in the fond memories of both the organizers and the participants as one of the shining highlights of the IUCr congress series and of IYCr!

Keynote lectures

Combining neutrons with high-performance computing to understand complex biological systems

[Paul Langan] Paul Langan

The technique of neutron protein crystallography is currently available at only four facilities in the world: ILL (France), Oak Ridge (USA), FRM-II (Germany) and J-PARC (Japan). The keynote speaker Paul Langan, after receiving his PhD in Biophysics from Keele U., UK, conducted experiments at ILL, LANSCE, and Oak Ridge, where he became the director of the biology and soft matter division. Currently, he is a Program Advisory Committee member of J-PARC in Japan and a member of the Scientific and Technical Advisory Panel of NMX in ESS.

In his keynote lecture, Langan presented an overview of neutron facilities at ORNL and gave examples of applications in biological research. He then discussed how the future challenges in biology are driving further technological developments that will lead to new understanding in the emerging areas of dynamic functional assemblies, disorder and flexibility, biological membranes and associated complexes, and biomolecular function and ligand binding.

Nobuo Niimura

Structural genomics of chromatin regulators for biological discovery and epigenetic therapy

[Cheryl Arrowsmith] Cheryl Arrowsmith

Cheryl Arrowsmith (Canada) presented a program for developing inhibitors of protein modifiers of epigenetics, i.e. heritable changes in phenotype caused by mechanisms other than DNA sequence. Epigenetic modifiers place, interpret or remove modifications like methylation and acetylation on DNA and associated proteins, and may be useful targets to repurpose diseased cells into non-dangerous states. X-ray crystallographic structures and assays are used to find inhibitors which are potent, selective, cell-active and non-toxic. Exciting examples of inhibitors of different protein modifiers which use diverse modes of inhibition were presented: a small molecule which competes for the histone binding site in a SET domain of lysine methyltransferase was brought to market as a research tool. Other lysine methyltransferase inhibitors which target the SAM co-factor binding site feature high specificity. An inhibitor acts allosterically against a dimeric arginine methyltransferase. A compound that prevents aberrant complex formation with fusion proteins in MLL-rearranged leukemia decreases the viability of these cancer cell lines. An inhibitor specific for the acetyl-lysine binding site in bromodomain-containing proteins is effective against a variety of cancer lines. A molecule specific for one malignant brain tumor protein family member acts by inducing protein dimerization. The program holds great promise for the production of molecules for the worldwide community for the investigation and treatment of a diverse set of diseases.

T. Martin Schmeing

Biological macromolecules

Crystallography of HIV/AIDS

The MS05 session entitled 'The crystallography of HIV/AIDS', chaired by A. Wlodawer (USA), was preceded by a keynote lecture given by E. Arnold (USA) in which he summarized his longstanding efforts aimed at characterization of HIV reverse transcriptase, a prime target for drug design. The studies of different classes of inhibitors bound to the enzyme were the key to creation of a number of successful anti-HIV agents. The failure of protease-directed drugs due to viral resistance and the methods of its prevention were discussed by C. Schiffer (USA). The two talks by P. Kwong (USA) and R. Diskin (Israel) dealt with anti-HIV vaccine design and the rational design of antibodies, respectively. While a vaccine is still not available, such studies go a long way to setting a path which may lead to its creation. A. Price (UK) gave an interesting talk on the interactions of the capsid protein with the host factors, while talks by K. Siu (Canada) and Y. Xiong (USA) dealt with structural investigations of other host proteins. The session provided an excellent summary of the state of the field 25 years after the first crystal structures of an HIV protein (protease) became available.

A. Wlodawer

Improving your crystallography: best practices and new methods

[MS22 speakers and chairs] MS22 speakers and chairs (from left): L. Redecke, M. Gerstel, R. Read, P. Afonine, Z. Dauter, G. Evans and M. Yamamoto (co-chair); inset: W. Hendrickson.

In microsym. MS22, the first three speakers presented new methods of diffraction data collection and analysis in the context of the multi-crystal approach, and the last three described improvements in structure determination techniques leading to more accurate structural models. G. Evans (UK) presented the current status of the microfocus beamline and multi-crystal data collection facility at the Diamond Light Source. W. Hendrickson (USA) described their novel S-SAD structure determinations using long wavelengths and many crystals with a cluster analysis. The new serial crystallography approach using SR compared with XFEL-SFX was presented by L. Redecke (Germany). M. Gerstel (UK) introduced the new index BDamage, identifying the regions in structures most affected by radiation damage. P. Afonine (USA) discussed the error sources of calculated electron-density maps and described the improved method of FEM (feature enhanced map), recently implemented in the Phenix software suite. In the last talk, R. Read (UK) presented modified likelihood functions concerned with tNCS applicable for molecular replacement and implemented in Phaser. The session was moved to a larger room after the first talk due to an overflow crowd.

Masaki Yamamoto

Small-angle X-ray scattering on biological macromolecules

Microsym. MS28 provided an impressive view of the state of the art in automation of data collection and analysis, together with recent results on complex systems. Recent developments in cryo-SAXS promise lower consumption of radiation-sensitive samples, enhanced automation and new options for time-resolved studies.

A study of cytokine:receptor interactions demonstrated the power of SAXS data and the seamless interface with other biostructural and biophysical techniques. A study of polyketide synthetases emphasized the need for expert sample preparation. A final problem elucidated bacterial protein:DNA packing. It was evident how beamline-based groups on both sides of the Atlantic have contributed to advance the field. Computational approaches to use the data for higher resolution modeling were discussed.

We wish to emphasize the importance of efforts to reduce ambiguity in data interpretation, through developing noise-independent fitting criteria, validation of data quality and three-dimensional models.

Bente Vestergaard and Zehra Sayers

Disease-related proteins

[MS53 speakers and chairs] MS53 speakers and chairs (from the left): F. Van Petegem, M. Rizzi, S. Ribeiro, B. DeLaBarre, M. Banfield, M. Miyano and J. Cherfils.

The microsym. MS53 gave an up-to-date view of how crystallography can be crucial for understanding the role played by specific proteins in the pathogenesis of neurodegenerative disorders, cancer and cardiovascular diseases. Examples of the use of structures for the development of pharmaceuticals endowed with either a spectacular specificity or a loose one that results in efficacious multi-targeting was illustrated, together with their use in understanding the molecular bases of mutations that cause a disease. Moreover, the fascinating interplay at the host-pathogen interface was covered with examples from diseases affecting humans or plants. D. Eisenberg (USA) showed how a conserved self-assembly mechanism affecting different proteins is at the base of different pathologies, and how crystallography is contributing to the elucidation of the structure of amyloid fibers and toxic oligomeric intermediates. Evolutionary links between different disease-related proteins were also illustrated.

Menico Rizzi and Sandra Ribeiro

Structure of metal compounds mimicking protein active sites

[MS91 speakers and chairs] MS91 speakers and chairs (left to right): J. Hall, G. Rohde, J. Kondo, C. Fischer and C. Cardin.

In microsym. MS91, C. Fischer (Germany), a synthetic chemist, described both expected and unexpected results in the model chemistry of molybdenum and tungsten oxidoreductase enzymes, highlighting the difficulties of emulating nature. G. Rohde (USA) described the challenging syntheses of methane monooxygenase intermediates. The work required low temperatures to study the dibridged FeIV-O-FeIV system, using crystallography and XAFS, and featuring the very short Fe-O distance of 1.8 Å. He described the highly reactive open-core structures of the form (Fe=O)-O-(Fe=O). A. Višnjevac (Croatia) described work on hydrophobic cavities created using a calixarene-type methodology to produce 'bowl' systems, which could contain CuI, CuII or ZnII.

The remainder of the session concerned mercury complexes of oligonucleotide duplexes (J. Kondo, Japan) and the interactions of ruthenium polypyridyl cations with nucleic acids (J. Hall, UK).

Christine Cardin and Pat McArdle

Physical and/or fundamental

Recent advances in quasicrystal research

[Precession pattern] [MS02 speakers and chairs]
False-color image of the high-energy integrated precession pattern from icosahedral Tb-Cd taken on the 6-ID-D beam line at the Advanced Photon Source. Credits: Diffraction pattern taken by A. Kreyssig, M. Ramazanoglu and A. I. Goldman. Samples grown by T. Kong and P. Canfield. All researchers from Ames Lab and Iowa State U. Publication: A. I. Goldman et al., Nature Materials 12, 714 (2013). MS02 speakers and chairs (left to right): An-Pang Tsai, S. Forster, S. Thiem, J. Wolny, H.-R. Sharma, A. Goldman; inset: T. Seki. Missing: F. Eriksson.
 

Microsym. MS02 entitled 'Recent advances in quasicrystal research' reported the state of the art of quasicrystals. A. Goldman (USA) reviewed progress in understanding the magnetic properties of rare-earth metal (R) containing icosahedral quasicrystals. Interesting results included: the discovery of a series of binary Cd88R12 quasicrystals, which exhibit short-range magnetic order, and the observation of long-range antiferromagnetic order in Cd6R approximants. The speaker reviewed Zn-Mg-R systems and described the new understanding of Cd-R systems. The magnetic properties of all R-containing quasicrystals are very similar, indicating the common feature of cluster-based intermetallic compounds. An open question is why long-range anti-ferromagnetism is present in the Cd6R approximants and not in Cd88R12 quasicrystals. Structure analysis of the quasicrystals may answer the question.

An-Pang Tsai

Electronic and magnetic phenomena at extreme conditions

[MS41 speakers and chairs] MS41 speakers and chairs: (from left, lower row) T. Yamanaka, G. Saleh, H. Nojiri, J. Attfield, S. Madson and K. Friese (co-chair); (from left, upper row) K. Prokes (co-chair) and K. Prassides.

Non-ambient pressure, temperature and/or magnetic fields often lead to novel electronic and magnetic states. In microsym. MS41 it became apparent that the term 'extreme conditions' is relative. J. Attfield (UK) showed that our ambient world could constitute extreme conditions for systems that were prepared under high pressure and temperatures and quenched. Unusual orbital order or giant negative thermal expansion phenomena can be stabilized. Novel field-induced magnetic phases can be studied most directly with scattering techniques. However, fields in excess of ∼17 T are achievable only in pulsed fields. The contribution of H. Nojiri (Japan) nicely summarized such techniques. K. Prassides (UK) described how superconductivity emerges under pressure from insulating antiferromagnetic alkali fullerides. Other talks focused on maximum entropy reconstruction of electron densities from precise X-ray diffraction data under pressure (T. Yamanaka, USA), X-ray and Mössbauer spectroscopy under pressure (S. Madsen, Denmark), and the theoretical study of ab initio prediction of the stability of Na2He compound under extreme pressure (G. Saleh, Russia).

K. Prokes

Diffuse scattering and partial disorder in complex structures.

[Urea inclusion compounds] Diffuse scattering in urea inclusion compounds (Rabiller).

Topics covered in MS42 included complex incommensurate structures in urea inclusion compounds by P. Rabiller (France), perovskite-based ferroelectrics by M. Pasciak (Czech Republic) and J. Pacaud (France), the disordered structure of crystalline sodium fluorosilicate by E. Stronks (Switzerland) and intergrowth zeolitic materials by W. Slawinski (Norway). In addition, Simonov (Switzerland) presented a new method for analyzing diffuse scattering involving the use of three-dimensional pair distribution functions (3D-PDF). The studies involved the use of X-ray scattering (both laboratory-based and synchrotron sources), neutron scattering and energy-filtered electron scattering.

Richard Welberry

XAFS

X-ray techniques for innovation in industry

[MS38 speakers and chairs] MS38 speakers and chairs (left to right): T. Kawaguchi, W. Łasocha, S. Monaco-Malbet, F. Gozzo, K. Lawniczak-Jablonska, J. Cutler, T. Wroblewski and A. Phillips.

Utilization of X-ray techniques in material characterization is increasingly important in development, innovation and commercialization. Topics in microsym. MS38 ranged from life science to materials science, and illustrated how dedicated support programs at light sources facilitate industrial engagement.

F. Gozzo (Switzerland) described how powder diffraction is important for drug development, including the detection of contamination at sub-percent level. T. Kawaguchi (Japan) presented work on improving our understanding of lithium nickel oxide battery material by applying site-selective diffraction anomalous fine-structure (DAFS) spectroscopy. W. Łasocha (Poland) described the development of various polyoxometalate catalysts for application in green chemistry and the production of adipic acid from cyclohexane. A. Phillips (UK) gave an example in metal-cyanide framework chemistry where neutrons and X-rays coupled with DFT calculations characterized metals in a framework. Along with industry examples, T. Wroblewski (Germany) and S. Monaco-Malbet (France) highlighted industrial liaison programs and how they have benefited small enterprises and large multi-national corporations.

Krystyna Lawniczak-Jablonska and Jeffrey Cutler

Instrumentation, techniques and/or computation

Recent advances in quasicrystal research 


Small-angle scattering for magnetism and magnetic structures  

In MS08, topics in magnetic SANS research were discussed including vortex and skyrmion lattices, 3He spin filters, Nd-Fe-B permanent magnets and perpendicular magnetic recording media. M. Eskildsen (USA) discussed vortex lattices in type-II superconductors. For Sr2RuO4, it was shown how the magnetic SANS technique could provide information on superconducting anisotropy and the nature of the pairing mechanism. SANS experiments on MgB2 in the presence of a small-amplitude AC magnetic field revealed the existence of dual power-law correlations, which drive the system to the ground state. The recently discovered skyrmion lattices in B20 compounds can be considered as a novel particle-like state of matter. S. Mühlbauer (Germany) outlined the potential use of skyrmion textures in spintronics applications. Nd-Fe-B magnets are an extremely important class of energy materials, which are used in hybrid electric vehicles and wind turbines. T. Ueno (Japan) showed how magnetic SANS can contribute to the understanding of the coercivity mechanism in this class of materials. 3He spin filters for polarizing and analyzing neutron beams are gaining popularity at neutron sources. P. Jiang (USA) reported on the properties and advantages of 3He spin filters (large acceptance angle and broad wavelength range) over conventional single-crystal or supermirror polarizers. The use of the SANS technique for studying the magnetic microstructure of perpendicular magnetic recording media and the magnetization-reversal process was demonstrated by S. Lee (UK). Polarized SANS provides a powerful means to separate weak magnetic signals that are on top of a large nuclear background.

Andreas Michels

Meso- and nanostructures developed via heterogeneous interfaces

[MS39 speakers and chairs] MS39 speakers and chairs (left to right): W. Tremel, H. Bernstein, J. Cambedouzou, M. Schmiele, K. Edler, E. Rosseeva, U. Vainio, D. Schwahn.

Microsym. MS39 covered topics ranging from biomineralisation, core-shell nanoparticles and protein function to small-angle scattering data analysis of aligned carbon nanotube forests. Highlights included invited presentations by W. Tremel (Germany) and E. Rosseeva (Germany) and a contributed one by U. Vainio (Germany). Both invited talks presented experiments on nanostructuring and self-assembly of calcium carbonate using a range of organic templates. Tremel also presented novel sample environments in levitating droplets. Stabilization of amorphous mineral polymorphs as a precursor of mineralization was described. Vainio's talk dealt with orientation distribution of shape-anisotropic materials determined by a generalized normal distribution function related to Kohlrausch's stretched exponential decay. The function is broadly applicable across a wide variety of materials, including those that form glasses.

Karen Edler

Materials or minerals

Structure determination from low-resolution data: when the going gets tough

[MS11 speakers and chairs] MS11 speakers and chairs (left to right): A. Meden, A. Edwards, K. Shankland, H. Gies, S. Smeets, P. Whitfield and I. Evans.

Diffraction data of limited resolution make structure solution difficult. The speakers of the MS11 microsym. presented various aspects of this problem and outlined different ways of solving it. K. Shankland (UK) and H. Gies (Germany) described the approach of using prior knowledge of the molecular geometry or building blocks for organic and inorganic (zeolite) structures, respectively. S. Smeets (Switzerland) described the use of complementary sources of information like electron microscopy. Two contributions elucidated the examples of applying Laue (A. Edwards, Australia) and TOF (P. Whitfield, USA) neutron diffraction for structure solution. In the discussion, the question of possible future development of a computer program for the automated simultaneous treatment of data from various sources, e.g. powder and electron diffraction or NMR or other spectroscopic data, was raised and the answer was positive.

Ivana Evans and Tone Meden

Role of defects in crystal structure formation, organization and stability

[MS15 speakers and chairs] MS15 speakers and chairs (left to right): S. Schorr, C. Ling, J. Hadermann, P. Ferreira, I. Richardson and S. Pereira.

Microsym. MS15 concerned the importance of defects in crystallography and materials science. Two contributions were particularly noteworthy. P. Ferreira (USA) showed deformation of nanoparticles observed in situ under phase contrast in conventional and aberration-corrected TEM. Evidence for nucleation of dislocations and dislocation motion was observed during in situ nano-indentation, but upon unloading the dislocations were no longer visible. J. Hadermann (Belgium) examined new modular oxide structures using lone pair cations as chemical scissors. She addressed the role of lone pair cations such as Bi3+ or Pb2+. Their flexibility reduces the strain that would otherwise be present at the interfaces separating structure modules. Hadermann showed that this concept allowed the introduction of crystallographic shear planes into a perovskite structure, a feat that was considered highly unlikely before.

Sérgio Pereira

Reports to be continued in Volume 22, Number 4