Speaker
Description
[1]Investigating model influence on the analytical resolution of neutron
reflectometry
Neutron reflectometry is an invaluable tool for the study of biological samples due to its sensitivity to atomic nuclei and their penetrative capabilities [2] [3] [4]. The resolution of the technique as de-fined by the diffraction limit is at about 10 Å. However, evidence from literature would suggest that this is not the case, as articles on this technique routinely describe resolving parameters which are smaller than this [5]..
Neutron reflectometry data is rarely analysed without any prior knowledge of the system i.e. what layers are present in the sample. Therefore, any analysis should always be viewed in the context of the model used. In this work, we investigate the relationship between the resolution and the choice of different models used, each with different numbers of parameters based on reasonable and justi-fied assumptions, to describe the system under consideration. Bayesian model selection [6] [1] is used to quantify the relative quality of the models relative to each other for varied number of con-trasts and the direct effect our ignorance or knowledge of the system has on the resolution.
Bibliography
[1] D. Sivia, W. David, K. Knight and S. Gull, "An introduction to Bayesian model selection," Physica D: Nonlinear Phenomena, pp. 234 - 242, 1993.
[2] L. A. Clifton, S. A. Holt, A. V. Hughes, E. L. Daulton, W. Arunmanee, F. Heinrich, S. Khalid, D. Jefferies, T. R. Charlton, J. R. P. Webster, C. J. Kinane and J. H. Lakey, "Self-Assembled Fluid Phase Floating Membranes with Tunable Water Inter-layers," Angewandte Chemie (International ed. in English), pp. 11952-11955, 2005.
[3] L. A. Clifton, N. Paracini, A. V. Hughes, J. H. Lakey, N.-J. Steinke, J. F. K. Cooper, M. Gavutis and M. W. A. Skoda, "Self-Assembled Fluid Phase Floating Membranes with Tunable Water Interlayers," Langmuir, pp. 13735-13744, 2017.
[4] A. V. Hughes, D. S. Patel, G. Widmalm, J. B. Klauda, L. A. Clifton and W. Im, "Physical Properties of Bacterial Outer Membrane Models: Neutron Reflectometry & Molecular Simulation," Biophysical Journal, pp. 1095-1104, 2017.
[5] S. A. Holt, A. P. Le Brun, C. F. Majkrzak, D. J. McGillivray, F. Heinrich, M. Lösche and J. H. Lakey, "An ion-channel-containing model membrane: structural determination by magnetic contrast neutron reflectometry," Soft Matter, pp. 2576-2586, 2009.
[6] S. D.S., W. Hamilton and G. Smith, "Analysis of neutron reflectivity data: maximum entropy, Bayesian spectral analysis and speckle holography," Physica B: Condensed Matter, pp. 121 - 138, 1991.
