Macromolecular crystallography radiation damage research: what's new?

An introductory overview of the special issue papers on radiation damage in this issue..

Radiation damage in room-temperature data acquisition with the PILATUS 6M pixel detector

Observations of the dose-rate effect in continuous X-ray diffraction data acquisition at room temperature are presented.

Similarities and differences in radiation damage at 100 K versus 160 K in a crystal of thermolysin

In a protein crystal an increase in the atomic B-factor after radiation exposure at 160 K correlates with the proximity to solvent channels.

Energy dependence of site-specific radiation damage in protein crystals

The energy dependence of specific radiation damage to sulfur sites in tetragonal HEWL lysozyme is studied.

Effective scavenging at cryotemperatures: further increasing the dose tolerance of protein crystals

Sodium nitrate, an electron scavenger, is shown to be an effective agent in reducing the rate of global radiation damage with increasing dose, and to be even more effective in quenching specific structural damage in native HEWL crystals at 100 K.

Correlated single-crystal electronic absorption spectroscopy and X-ray crystallography at NSLS beamline X26-C

The instrumentation and methods available for collecting almost simultaneous single-crystal electronic absorption correlated with X-ray diffraction data at NSLS beamline X26-C are reviewed, as well as a very brief outline of its Raman spectroscopy capability.

Revealing low-dose radiation damage using single-crystal spectroscopy

Data on the rapid reduction of haem proteins in the X-ray beam at synchrotron sources are presented. The use of single-crystal spectroscopy to detect these changes and their implication for diffraction data collection from oxidized species is also discussed.

Additional phase information from UV damage of selenome­thionine labelled proteins

Successful examples of ultraviolet radiation-damage-induced phasing with anomalous scattering from selenomethionine protein crystals have been demonstrated.

Experimental procedure for the characterization of radiation damage in macromolecular crystals

A novel automatic procedure to determine the sensitivity of macromolecular crystals to radiation damage is presented. The information extracted from this procedure can be directly used for optimal planning of data collection or/and beamline calibration.

Assessment of radiation damage behaviour in a large collection of empirically optimized datasets highlights the importance of unmeasured complicating effects

A retrospective analysis of radiation damage behaviour in a statistically significant number of real-life datasets is presented, in order to gauge the importance of the complications not yet measured or rigorously evaluated in current experiments, and the challenges that remain before radiation damage can be considered a problem solved in practice.

Radiation damage in single-particle cryo-electron microscopy: effects of dose and dose rate

The effects of dose and dose-rate were investigated for single-particle cryo-electron microscopy using stroboscopic data collection. A dose-rate effect was observed favoring lower flux densities.

Three-dimensional diffraction mapping by tuning the X-ray energy

Three-dimensional reciprocal-space maps of a single SiGe island around the Si(004) Bragg peak are recorded using an energy-tuning technique with a microfocused X-ray beam with compound refractive lenses as focusing optics.

Qu­antitative local structure determination in mica crystals: ab initio simulations of polarization XANES at the potassium K-edge

Angle-resolved XANES at the potassium K-edge and single-crystal X-ray diffraction experiments are combined to characterize structural distortions and compositional disorder of micas. Full-multiple-scattering XANES analysis is presented and limitations of the muffin-tin potential in layered systems are discussed.

Suppression of ring artefacts when tomographing anisotropically attenuating samples

An intensity normalization technique is proposed to suppress ring artefacts of varying strength. The method was applied to an elongated sample in a monochromatic beam and to a sample with highly attenuated parts in a white beam.

Reconstruction of electron beam distribution using phase-retrieval algorithm

The transverse distribution of an electron beam in a storage ring can be reconstructed by using a phase-retrieval algorithm.

High-efficiency Fresnel zone plates for hard X-rays by 100 keV e-beam lithography and electroplating

The efficiencies of several Fresnel zone plates, that were fabricated using a direct-write method with high-energy electrons, were measured over a wide range of photon energies.

In situ diffuse reflectance IR spectroscopy and X-ray absorption spectroscopy for fast catalytic processes

A new instrument for synchronous in situ investigations by infrared and X-ray absorption spectroscopies was designed and built at the Synchrotron Catalysis Consortium, NSLS, Brookhaven National Laboratory. It combines two complementary methods, DRIFTS and XAFS, for solving electronic, structural and kinetic problems for a wide range of catalysts, reactive conditions and time scales.

Specific molecular and cellular events induced by irradiated X-ray photoactivatable drugs raise the problem of co-toxicities: particular consequences for anti-cancer synchrotron therapy

X-ray photoactivatable drugs and co-toxicities: consequences for synchrotron radiotherapy.

Fast X-ray microdiffraction techniques for studying irreversible transformations in materials

Techniques are described for X-ray diffraction combining micrometer-scale spatial resolution with microsecond-scale temporal resolution for studying rapid localized irreversible transformations in materials.

Calcifications in human osteoarthritic articular cartilage: ex vivo assessment of calcium compounds using XANES spectroscopy

X-ray absorption near-edge structure spectroscopy has been used to accurately characterize sparse calcium-containing crystals in human OA cartilage.

Development of a hard X-ray delay line for X-ray photon correlation spectroscopy and jitter-free pump–probe experiments at X-ray free-electron laser sources

A prototype device capable of splitting an X-ray pulse into two adjustable fractions, delaying one of them with the aim of performing split pulse X-ray photon correlation spectroscopy and pump–probe type studies was designed and manufactured. Time delays up to 2.95 ns have been demonstrated. The achieved contrast values of 56% indicate a feasibility of performing coherence-based experiments with the delay line.

New developments in fabrication of high-energy-resolution analyzers for inelastic X-ray spectroscopy

New improvements related to the fabrication of spherical bent analyzers for 1 meV energy-resolution inelastic X-ray scattering spectroscopy are presented.

High-resolution stress mapping of polycrystalline alumina compression using synchrotron X-ray diffraction

High-energy X-rays were used to capture powder diffraction profiles over a half-section of a polycrystalline alumina parallelepiped sample under an increasing uniaxial compressive load. The data was converted to strain and results were used for stress mapping of the sample.

In situ powder diffraction study of belite sulfoaluminate clinkering

Clinkering reactions and processes have been established for belite sulfoaluminate cements by high-energy synchrotron powder diffraction at high temperatures.

Geometrical layout and optics modelling of the surface science beamline station at the SESAME synchrotron radiation facility

A quantitative analysis and computer modelling of the surface science beamline station D09 at the SESAME synchrotron radiation facility are presented.

X-ray collimation by crystals with precise parabolic holes based on diffractive–refractive optics

X-ray collimation as a novel application of diffractive–refractive optics was studied theoretically and experimentally. A set-up with two crystals in a dispersive arrangement successfully demonstrated X-ray collimation in the energy range 6.3–18.8 keV.

Use of Soller slits to remove reference foil fluorescence from transmission spectra

Use of Soller slits to remove back-fluorescence from the reference foil helps provide more accurate transmission X-ray absorption spectra of weak samples.

Synchrotron-radiation-induced oxidation of selenite to selenate in coal-derived fly ash

Based on variations observed in successive Se XAFS scans of a coal-derived fly-ash, 15–20% of the selenite in the fly-ash is estimated to have oxidized to selenate as a result of exposure to synchrotron radiation for 2 h.

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