Meeting report

BCA Winter 2001 meeting reports

Biological sciences

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The winter meeting of the Biological Science Group of the BCA focused on recent results in membrane protein research, and covered expression, crystallization, kinetic crystallography, electron microscopy, single-molecule observations and structural studies. S. Iwata reported the structure of formate dehydrogenase-N at 1.6 Å, the highest resolution for a membrane protein complex obtained so far. More than 200 delegates attended the largest ever BSG winter meeting, which attracted financial support from 10 sponsors.

So Iwata and Bernadette Byrne

Chemical crystallography

'Mesomolecular Crystallography' and structure and bonding in large molecular and supramolecular materials was the topic of the BCA Chemical Crystallography Group.

M. Schroder discussed construction of framework polymers of catenates, helicates and porous materials based on n-connected nets which can arise as a result of metal-metal interactions between organic chains.

Borrowing an idea from synthetic organic chemistry, A. Burrows (Bath) used 'Combinatorial crystallography' to produce supramolecular network formation fashioned from dicarboxylates and thiosemicarbazides in a systematic way, other topics discussed included Hydrogen bonding in Sulfimides (K. Holmes, Loughborough), high nuclearity 3D-Metal cages with unusual magnetic properties (R. Winpenny, Manchester), structures involving large numbers of formula units in the crystallographic asymmetric unit (J. Steed, King’s College), the impact of anion size on the structure of polycationic chains in co-ordination polymers (A. Khlobystov, Nottingham), and network structures from the host molecule CTV (M. Hardie, Leeds). Finally, A. Bond (Cambridge) discussed crystal structures of multi-porphyrin oligomers and the definition of the term 'mesomolecular crystallography'.

Harry Powell

Industrial group

Pilkington, a company with manufacturing plants in 25 countries, developed float glass in the 1950s. Many Pilkington products are thin films deposited on glass to improve thermal, optical or mechanical properties. At it’s technical center in Lancashire, powder diffraction is used to check the quality of raw materials, identify the phases in dusts and corrosion products and do troubleshooting on final products. Using X-ray reflectometry, one can obtain information about the film thickness, density and roughness.

The polymorphic form of a drug influences its stability, solubility and hence bioavailability, A. Kavanaugh described how powder diffraction is used to characterize pharmaceuticals at Astra Zeneca where a new system with a point source and a 2-dimensional position sensitive detector is ideal for very small samples and spatially resolved work. M. Abraham (U. of Oxford) described production of nanocrystalline nickel 5 times harder than conventional large grained nickel that is produced by electrodeposition. K. Rogers talked about CdTe-CdS solar cells, synthetic materials that mimic human bone and can be used to repair breaks and make implants, and SAXS on breast tissue with and without cancer.

D. Beveridge (Ilford) discussed silver halide photography, the challenges of trying to identify dyes and pigments in new inkjet products, and how a crystal structure can strongly influence color. I. Slipper described determining glass content in samples of ground granulated blast furnace slag (an additive to cement) and efforts to automate the analysis process.

Many industrial systems cannot be analyzed by classical line profile approaches. Steve Norval (ICI) described a new approach, Linear optimization of a simulated set (LOSS) to handle such problems.

C. Frampton, Chairman of the IG, presented Ian Langford with the Industrial Group Award for his work on profile analysis. Ian has published extensively on zinc oxides which are used in paints, ceramics, catalysts, lubricants, paper, electronic devices, pharmaceuticals and even chemical smoke. Appropriately the award included a Beevers model of zinc oxide.

Mary Vickers, Cambridge U.

Physical crystallography group

A symposium on applications of high-pressure techniques in the study of crystal structures was organized at Daresbury Laboratory. There were talks on the complimentarity of Raman spectroscopy and X-ray analysis (A. Jephcoat, Oxford U.), neutron diffraction single-crystal techniques (D. Keen), high-pressure powder-diffraction using synchrotron radiation (M. Mezouar, ESRF), and CCD detectors in high-pressure crystallography (S. Parsons, U. of Edinburgh)

David Allen
BCA Crystallography News, No. 80