title: Direct phasing in femtosecond nanocrystallography. II. Phase retrieval.
abstract: X-ray free-electron laser diffraction patterns from protein nanocrystals provide information on the diffracted amplitudes between the Bragg reflections, offering the possibility of direct phase retrieval without the use of ancillary experimental diffraction data [Spence et al. (2011). Opt. Express, 19, 2866-2873]. The estimated continuous transform is highly noisy however [Chen et al. (2014). Acta Cryst. A70, 143-153]. This second of a series of two papers describes a data-selection strategy to ameliorate the effects of the high noise levels and the subsequent use of iterative phase-retrieval algorithms to reconstruct the electron density. Simulation results show that employing such a strategy increases the noise levels that can be tolerated.
authors.affiliation: Computational Imaging Group, Department of Electrical and Computer Engineering, University of Canterbury, Christchurch, New Zealand.
authors.forename: Joe P J
authors.initials: JP
authors.lastname: Chen
authors.affiliation: Department of Physics, Arizona State University, Tempe, AZ 85287, USA.
authors.forename: John C H
authors.initials: JC
authors.lastname: Spence
authors.affiliation: Computational Imaging Group, Department of Electrical and Computer Engineering, University of Canterbury, Christchurch, New Zealand.
authors.forename: Rick P
authors.initials: RP
authors.lastname: Millane
mesh_terms: D000465:Algorithms; D051398:Aquaporin 1 / Q000737:chemistry; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D005583:Fourier Analysis; D007091:Image Processing, Computer-Assisted; D007834:Lasers; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology
chemical_list: D051398:Aquaporin 1
keywords: X-ray free-electron lasers; direct phasing; femtosecond crystallography; iterative transform algorithms; nanocrystals; shape transform