The BCA Spring Meeting 1998 at the University of St. Andrews was a useful and well-attended conference that focussed on many important areas of crystallographic research at the moment. Firstly, from a personal point of view, I found the electronic means of abstract submission, by uploading a PC document via the WWW to the BCA site, an excellent means of abstract submission. This worked very smoothly as a trial run to the IUCr99 in Glasgow.
This years' conference saw the absence of the Bragg and Lonsdale lectures and thus the lecture with the most historical perspective was the opening plenary lecture, 38 Years Hard Labour as a Fibre Diffractionist, delivered by Struther Arnott. This was an illuminating and entertaining account of the wealth of information lying in the fibre diffraction patterns of polynucleotides. It was also quite disconcerting for the crystallographer who possibly might be losing a lot of information by persisting in working with sequences, which are known to crystallise! Malcolm Walkinshaw's lecture, Cyclophins as Targets for Ligand Design, contained examples of the cyclophin family from various species which bind the immunosuppresant cyclosporin A. Samantha A. Wynne, from the LMB Cambridge, gave an account of the structure of the hepatitis B capsid protein solved from data collected to 3.6Å at the ESRF. This lecture was part of the BSG Hot Structures session; the capsid, which surrounds the DNA virus core, had spectacular icosahedral symmetry as well as 5-fold, 2-fold and 3-fold symmetry. Samar Hasnain discussed the structure of Superoxide Dismutase and the mechanism of its reduction. Two crystal forms of the native compound were produced and data collected to 2.3 and 1.6Å at Daresbury stations 9.5 and 9.6 respectively. These were solved and refined in the space groups C2221 andof potential non -linear optically active compounds. This lecture contained results obtained from single-crystal neutron diffraction at the ILL and ISIS and charge density analysis derived from X-N data. However, I believe it was too soon for the CCG to devote a full session to this subject after the 1996 Cambridge meeting. The Twinning workshop had a good general introduction to the problem of twinning and its treatment in refinement. As a SMART user, I am familiar with the XPREP package although most of the participants were not. I believe it would have been a good idea to include other manufacturer's software here as well. In the commercial exhibition, I was interested in the MSC method for the production of Xe derivatives for collecting Multiwavelength Anomalous Dispersion (MAD) macromolecular data.
Many of the posters presented contained excellent work: Madeline Helliwell's poster, in particular, interested me. This illustrated the enormous and growing importance of Multiwavelength Anomalous Dispersion in chemical crystallography. The compound under investigation was a molecular sieve with the formula Na6[CoxZnxPO4]6 The data had been collected from a single crystal using MoKa radiation but the lack of scattering contrast between the cobalt and zinc atoms had not allowed their positions and hence ratios to be determined. The MAD data collected at the ELETTRA close to the K absorption edges of Co and Zn allowed f' Fourier maps to be calculated, the Co and Zn atoms to be pinpointed and their ratios determined at Na6[Co0.2Zn0.8PO4]6.
I presented one poster in the CCG session jointly with Elena S. Alekseyeva entitled The Effect of Boranes on the Carbonyl Group and Hydrogen-Bonding in Carborane Derivatives and one in the BSG poster session, Ultra Low-Temperature Crystallographic Studies on CEW-Lysozyme, Using the Fddd Cryo-Diffractometer at Durham. I had a lot of interesting discussions about this with mainly protein crystallographers who were interesting in the possibilities of getting improved data sets at low temperature. These discussions were well appreciated and for this and the opportunity to attend this lively meeting I thank the BCA for my bursary.
Janet M.Moloney
University of Durham
The ERICE school programme was constructed such that an underlying theme pervaded each session. A more introductory lecture was often included at the start of a session in order to brief the more unfamiliar subjects to its participants. Several class discussions, following one of these themes, took place after the relevant session. These allowed us to discuss the overall theme in a more general and informal manner. Moreover, hands-on computing sessions also followed up specific lectures thereby helping to bring the lecture material more to life and allowing the participants to learn new software.
In particular, three general themes seemed to dominate the conference: intermolecular interactions, polymorphism and experimental techniques. On the first of these topics, I was especially enthused by Desiraju's overview of the present state of the subject and Bernstein's talk on applying graph set theory to the CSD. All of the polymorphism talks I found very informative especially since I initially possessed very little knowledge in this topic area. Lecturers on the third of these themes presented overviews of commonly used technology and exciting new developments such as CCD area detectors and liquid He cryostreams. My highlights of the meeting also came from some of the more 'stand-alone' lectures, in particular, Buergi's talk and computing session on thermal motion analysis, Brock's discussion on what one can learn from space group frequencies in the CSD, Evan's lecture on negative thermal expansion and Bruce's enlightening talk on ab initio approaches to solve powder diffraction patterns.
My main contribution to the meeting was in the form of a poster presentation which was presented in the first of the three hour sessions. I chose to present work on the role of intermolecular interactions in determining non-linear optical properties. This gave me the opportunity to discuss my results and possible extensions to my present approaches with many participants.
Last but by no means least, I think that one of the strong assets of the school was that the majority of lecturers stayed throughout the duration of the conference Therefore, one had the rare opportunity to have one-on-one detailed discussions and form new collaborations with leaders in each field of crystallography.
Jacqueline M.Cole,
University of Kent at Canterbury,
15 July 1998,
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