George is developing machine learning methods for classification and visualisation of experimental data. The first part of his project involves identification of metabolite changes in plants under changing environmental conditions, including the effect of auxinic herbicides. He is also looking at formulation of these herbicides to find ways of increasing their efficiency and reducing environmental impact.
In his spare time George may be found running.
Laura is testing properties of new formulations of pharmaceutical materials. She is aiming to measure and understand the changes in dissolution rate of common pharmaceuticals when they are cocrystallised with different coformers.
In her spare time Laura swims, runs and cycles as part of the University Triathlon Team.
James is investigating partial proton transfer in a hydrogen bond in some multi-component molecular materials. He is using single crystal diffraction, solid state NMR and computational modeling.
James tempers his enthusiasm for solid state chemistry by playing mixed lacrosse for the University.
J. Chem. Inf. Model., 2016, 56 (12), 2347–2352 doi: 10.1021/acs.jcim.6b00565
A new molecular descriptor, nConf20, based on chemical connectivity, is presented which captures the accessible conformational space of a molecule. Currently the best available 2-dimensional descriptors for quantifying the flexibility of a particular molecule are the rotatable bond count (RBC) and the Kier flexibility index. We present a descriptor which captures this information by sampling the conformational space of a molecule using the RDKit conformer generator. Flexibility has previously been identified as a key feature in determining whether a molecule is likely to crystallize or not. For this application, nConf20 significantly outperforms previously reported single-variable classifiers and also assists rule-based analysis of black-box machine learning classification algorithms.
The sixth Moroccan school of Crystallography was held in November 2016 at Université Moulay Ismaïl in the historic Moroccan city of Meknes. Richard Cooper gave a lecture on Structure Validation and Visualisation and a one day workshop on Refinement and Validation using the CRYSTALS software.
Acta. Cryst. (2016) B72 661-683 (Feature Article) [ doi:10.1107/S2052520616012890 ]
Direct determination of the Flack parameter as part of the structure refinement procedure usually gives different, though similar, values to post-refinement methods. The source of this discrepancy has been probed by analysing a range of data sets taken from the recent literature. Most significantly, it was observed that the directly refined Flack (x) parameter and its standard uncertainty are usually not much influenced by changes in the refinement weighting schemes, but if they are then there are probably problems with the data or model. Post-refinement analyses give Flack parameters strongly influenced by the choice of weights. Weights derived from those used in the main least squares lead to post-refinement estimates of the Flack parameters and their standard uncertainties very similar to those obtained by direct refinement. Weights derived from the variances of the observed structure amplitudes are more appropriate and often yield post-refinement Flack parameters similar to those from direct refinement, but always with lower standard uncertainties. Substantial disagreement between direct and post-refinement determinations are strongly indicative of problems with the data, which may be difficult to identify. Examples drawn from 28 structure determinations are provided showing a range of different underlying problems. It seems likely that post-refinement methods taking into account the slope of the normal probability plot are currently the most robust estimators of absolute structure and should be reported along with the directly refined values.
Publisher’s copy
Acta. Cryst. (2016) B72(4), 439-459 [ doi:10.1107/S2052520616007447 ] A. M. Reilly, R. I. Cooper, C. S. Adjiman, S. Bhattacharya, A. D. Boese, J. G. Brandenburg, P. J. Bygrave, R. Bylsma, J. E. Campbell, R. Car, D. H. Case, R. Chadha, J. C. Cole, K. Cosburn, H. M. Cuppen, F. Curtis, G. M. Day, R. A. DiStasio Jr, A. Dzyabchenko, B. P. van Eijck, D. M. Elking, J. A. van den Ende, J. C. Facelli, M. B. Ferraro, L. Fusti-Molnar, C.-A. Gatsiou, T. S. Gee, R. de Gelder, L. M. Ghiringhelli, H. Goto, S. Grimme, R. Guo, D. W. M. Hofmann, J. Hoja, R. K. Hylton, L. Iuzzolino, W. Jankiewicz, D. T. de Jong, J. Kendrick, N. J. J. de Klerk, H.-Y. Ko, L. N. Kuleshova, X. Li, S. Lohani, F. J. J. Leusen, A. M. Lund, J. Lv, Y. Ma, N. Marom, A. E. Masunov, P. McCabe, D. P. McMahon, H. Meekes, M. P. Metz, A. J. Misquitta, S. Mohamed, B. Monserrat, R. J. Needs, M. A. Neumann, J. Nyman, S. Obata, H. Oberhofer, A. R. Oganov, A. M. Orendt, G. I. Pagola, C. C. Pantelides, C. J. Pickard, R. Podeszwa, L. S. Price, S. L. Price, A. Pulido, M. G. Read, K. Reuter, E. Schneider, C. Schober, G. P. Shields, P. Singh, I. J. Sugden, K. Szalewicz, C. R. Taylor, A. Tkatchenko, M. E. Tuckerman, F. Vacarro, M. Vasileiadis, A. Vazquez-Mayagoitia, L. Vogt, Y. Wang, R. E. Watson, G. A. de Wijs, J. Yang, Q. Zhu and C. R. Groom
The sixth blind test of organic crystal structure prediction (CSP) methods has been held, with five target systems: a small nearly rigid molecule, a polymorphic former drug candidate, a chloride salt hydrate, a co-crystal and a bulky flexible molecule. This blind test has seen substantial growth in the number of participants, with the broad range of prediction methods giving a unique insight into the state of the art in the field.
Publisher’s copy
Alex is undertaking a research project attempting to automatically model severe disorder with crystal structures using a Monte-Carlo approach. Alex is firmly in the computational side of the research group avoiding any crystallisation or actual diffraction at all costs.
Oliver joins the group undertaking a project searching for trends and correlations between crystal structure similarity and molecular similarity. He will also attempt to extend his analysis to co-crystal formation rules for which he will undertake and analyse a significant number of combinatorial experiments.
Outside work he spends much of his free time at the bank in his role as treasurer of various adventurous University societies including caving, orienteering and scuba diving.