Two in situ `nanoreactors' for high-resolution imaging of catalysts have been designed and applied at the hard X-ray nanoprobe endstation at beamline P06 of the PETRA III synchrotron radiation source. The reactors house samples supported on commercial MEMS chips, and were applied for complementary hard X-ray ptychography (23 nm spatial resolution) and transmission electron microscopy, with additional X-ray fluorescence measurements. The reactors allow pressures of 100 kPa and temperatures of up to 1573 K, offering a wide range of conditions relevant for catalysis. Ptychographic tomography was demonstrated at limited tilting angles of at least ±35° within the reactors and ±65° on the naked sample holders. Two case studies were selected to demonstrate the functionality of the reactors: (i) annealing of hierarchical nanoporous gold up to 923 K under inert He environment and (ii) acquisition of a ptychographic projection series at ±35° of a hierarchically structured macroporous zeolite sample under ambient conditions. The reactors are shown to be a flexible and modular platform for in situ studies in catalysis and materials science which may be adapted for a range of sample and experiment types, opening new characterization pathways in correlative multimodal in situ analysis of functional materials at work. The cells will presently be made available for all interested users of beamline P06 at PETRA III.

The European X-ray Free-Electron Laser (EuXFEL) delivers extremely intense (>1012 photons pulse−1 and up to 27000 pulses s−1), ultrashort (<100 fs) and transversely coherent X-ray radiation, at a repetition rate of up to 4.5 MHz. Its unique X-ray beam parameters enable novel and groundbreaking experiments in ultrafast photochemistry and material sciences at the Femtosecond X-ray Experiments (FXE) scientific instrument. This paper provides an overview of the currently implemented experimental baseline instrumentation and its performance during the commissioning phase, and a preview of planned improvements. FXE's versatile instrumentation combines the simultaneous application of forward X-ray scattering and X-ray spectroscopy techniques with femtosecond time resolution. These methods will eventually permit exploitation of wide-angle X-ray scattering studies and X-ray emission spectroscopy, along with X-ray absorption spectroscopy, including resonant inelastic X-ray scattering and X-ray Raman scattering. A suite of ultrafast optical lasers throughout the UV–visible and near-IR ranges (extending up to mid-IR in the near future) with pulse length down to 15 fs, synchronized to the X-ray source, serve to initiate dynamic changes in the sample. Time-delayed hard X-ray pulses in the 5–20 keV range are used to probe the ensuing dynamic processes using the suite of X-ray probe tools. FXE is equipped with a primary monochromator, a primary and secondary single-shot spectrometer, and a timing tool to correct the residual timing jitter between laser and X-ray pulses.

Porous, high-surface-area electrode architectures are described that allow structural characterization of interfacial amorphous thin films with high spatial resolution under device-relevant functional electrochemical conditions using high-energy X-ray (>50 keV) scattering and pair distribution function (PDF) analysis. Porous electrodes were fabricated from glass-capillary array membranes coated with conformal transparent conductive oxide layers, consisting of either a 40 nm–50 nm crystalline indium tin oxide or a 100 nm–150 nm-thick amorphous indium zinc oxide deposited by atomic layer deposition. These porous electrodes solve the problem of insufficient interaction volumes for catalyst thin films in two-dimensional working electrode designs and provide sufficiently low scattering backgrounds to enable high-resolution signal collection from interfacial thin-film catalysts. For example, PDF measurements were readily obtained with 0.2 Å spatial resolution for amorphous cobalt oxide films with thicknesses down to 60 nm when deposited on a porous electrode with 40 µm-diameter pores. This level of resolution resolves the cobaltate domain size and structure, the presence of defect sites assigned to the domain edges, and the changes in fine structure upon redox state change that are relevant to quantitative structure–function modeling. The results suggest the opportunity to leverage the porous, electrode architectures for PDF analysis of nanometre-scale surface-supported molecular catalysts. In addition, a compact 3D-printed electrochemical cell in a three-electrode configuration is described which is designed to allow for simultaneous X-ray transmission and electrolyte flow through the porous working electrode.

Being able to visualize biology at the molecular level is essential for our understanding of the world. A structural biology approach reveals the molecular basis of disease processes and can guide the design of new drugs as well as aid in the optimization of existing medicines. However, due to the lack of a synchrotron light source, adequate infrastructure, skilled persons and incentives for scientists in addition to limited financial support, the majority of countries across the African continent do not conduct structural biology research. Nevertheless, with technological advances such as robotic protein crystallization and remote data collection capabilities offered by many synchrotron light sources, X-ray crystallography is now potentially accessible to Africa-based scientists. This leap in technology led to the establishment in 2017 of BioStruct-Africa, a non-profit organization (Swedish corporate ID: 802509-6689) whose core aim is capacity building for African students and researchers in the field of structural biology with a focus on prevalent diseases in the African continent. The team is mainly composed of, but not limited to, a group of structural biologists from the African diaspora. The members of BioStruct-Africa have taken up the mantle to serve as a catalyst in order to facilitate the information and technology transfer to those with the greatest desire and need within Africa. BioStruct-Africa achieves this by organizing workshops onsite at our partner universities and institutions based in Africa, followed by post-hoc online mentoring of participants to ensure sustainable capacity building. The workshops provide a theoretical background on protein crystallography, hands-on practical experience in protein crystallization, crystal harvesting and cryo-cooling, live remote data collection on a synchrotron beamline, but most importantly the links to drive further collaboration through research. Capacity building for Africa-based researchers in structural biology is crucial to win the fight against the neglected tropical diseases, e.g. ascariasis, hookworm, trichuriasis, lymphatic filariasis, active trachoma, loiasis, yellow fever, leprosy, rabies, sleeping sickness, onchocerciasis, schistosomiasis, etc., that constitute significant health, social and economic burdens to the continent. BioStruct-Africa aims to build local and national expertise that will have direct benefits for healthcare within the continent.

Nanoparticles are essential electrocatalysts in chemical production, water treatment and energy conversion, but engineering efficient and specific catalysts requires understanding complex structure–reactivity relations. Recent experiments have shown that Bragg coherent diffraction imaging might be a powerful tool in this regard. The technique provides three-dimensional lattice strain fields from which surface reactivity maps can be inferred. However, all experiments published so far have investigated particles an order of magnitude larger than those used in practical applications. Studying smaller particles quickly becomes demanding as the diffracted intensity falls. Here, in situ nanodiffraction data from 60 nm Au nanoparticles under electrochemical control collected at the hard X-ray nanoprobe beamline of MAX IV, NanoMAX, are presented. Two-dimensional image reconstructions of these particles are produced, and it is estimated that NanoMAX, which is now open for general users, has the requisites for three-dimensional imaging of particles of a size relevant for catalytic applications. This represents the first demonstration of coherent X-ray diffraction experiments performed at a diffraction-limited storage ring, and illustrates the importance of these new sources for experiments where coherence properties become crucial.

A simple approach exploits quantum properties to justify the dependence on γ4 of the total synchrotron emitted power. It also clarifies some apparent puzzles and brings to light the underlying, multiple relativistic phenomena.

The transmission of the optical components of the Bernina branch of the Aramis beamline at SwissFEL has been measured with an X-ray gas monitor from DESY and compared with a PSI gas detector upstream of the optical components. The transmission efficiencies of the Mo, Si and SiC mirror coatings of the Aramis beamline and the various other in-beam components were evaluated and compared with theoretical calculations, showing an agreement of 6% or better in all cases. The experiment has also shown the efficacy of the high-harmonic rejection mirrors at the Bernina branch of the Aramis beamline at SwissFEL, and characterized the transmission efficiency of the on-line spectrometer in the Aramis beamline. The theoretical transmission of the mirror coatings match the experimental data to within 7%. The accuracy of these measurements was checked against a radiative bolometer from a Japanese collaboration and found to agree to a level of 4% or better. Further comparisons with a diamond detector from a US-based inter-institute collaboration demonstrated a good agreement for the attenuator settings of the beamline.

Calibration of area detectors from powder diffraction standards is widely used at synchrotron beamlines. From a single diffraction image, it is not possible to determine both the sample-to-detector distance and the wavelength, but, with images taken from multiple positions along the beam direction and where the relative displacement is known, the sample-to-detector distance and wavelength can both be determined with good precision. An example calibration using the GSAS-II software package is presented.

A simple and robust tool for spatio-temporal overlap of THz and XUV pulses in in-vacuum pump–probe experiments is presented. The technique exploits ultrafast changes of the optical properties in semiconductors (i.e. silicon) driven by ultrashort XUV pulses that are probed by THz pulses. This work demonstrates that this tool can be used for a large range of XUV fluences that are significantly lower than when probing by visible and near-infrared pulses. This tool is mainly targeted at emerging X-ray free-electron laser facilities, but can be utilized also at table-top high-harmonics sources.

Multilayer monochromator devices are commonly used at (imaging) beamlines of synchrotron facilities to shape the X-ray beam to relatively small bandwidth and high intensity. However, stripe artefacts are often observed and can deteriorate the image quality. Although the intensity distribution of these artefacts has been described in the literature, their spectral distribution is currently unknown. To assess the spatio-spectral properties of the monochromated X-ray beam, the direct beam has been measured for the first time using a hyperspectral X-ray detector. The results show a large number of spectral features with different spatial distributions for a [Ru, B4C] strip monochromator, associated primarily with the higher-order harmonics of the undulator and monochromator. It is found that their relative contributions are sufficiently low to avoid an influence on the imaging data. The [V, B4C] strip suppresses these high-order harmonics even more than the former, yet at the cost of reduced efficiency.

Following the recent demonstration of grazing-incidence X-ray fluorescence (GIXRF)-based characterization of the 3D atomic distribution of different elements and dimensional parameters of periodic nanoscale structures, this work presents a new computational scheme for the simulation of the angular-dependent fluorescence intensities from such periodic 2D and 3D nanoscale structures. The computational scheme is based on the dynamical diffraction theory in many-beam approximation, which allows a semi-analytical solution to the Sherman equation to be derived in a linear-algebraic form. The computational scheme has been used to analyze recently published GIXRF data measured on 2D Si3N4 lamellar gratings, as well as on periodically structured 3D Cr nanopillars. Both the dimensional and structural parameters of these nanostructures have been reconstructed by fitting numerical simulations to the experimental GIXRF data. Obtained results show good agreement with nominal parameters used in the manufacturing of the structures, as well as with reconstructed parameters based on the previously published finite-element-method simulations, in the case of the Si3N4 grating.

With the introduction of the multi-bend achromats in the new fourth-generation storage rings the emittance has decreased by an order of magnitude resulting in increased brightness. However, the higher brightness comes with smaller beam sizes and narrower radiation cones. As a consequence, the requirements on mechanical stability regarding the beamline components increases. Here an innovative five-axis parallel kinematic mirror unit for use with soft X-ray beamlines using off-axis grazing-incidence optics is presented. Using simulations and measurements from the HIPPIE beamline at the MAX IV Laboratory it is shown that it has no Eigen frequencies below 90 Hz. Its positioning accuracy is better than 25 nm linearly and 17–35 µrad angularly depending on the mirror chamber dimensions.

A simple two-spindle based lathe system for the preparation of cylindrical samples intended for X-ray tomography is presented. The setup can operate at room temperature as well as under cryogenic conditions, allowing the preparation of samples down to 20 and 50 µm in diameter, respectively, within minutes. Case studies are presented involving the preparation of a brittle biomineral brachiopod shell and cryogenically fixed soft brain tissue, and their examination by means of ptychographic X-ray computed tomography reveals the preparation method to be mainly free from causing artefacts. Since this lathe system easily yields near-cylindrical samples ideal for tomography, a usage for a wide variety of otherwise challenging specimens is anticipated, in addition to potential use as a time- and cost-saving tool prior to focused ion-beam milling. Fast sample preparation becomes especially important in relation to shorter measurement times expected in next-generation synchrotron sources.

A portable IR fiber laser-heating system, optimized for X-ray emission spectroscopy (XES) and nuclear inelastic scattering (NIS) spectroscopy with signal collection through the radial opening of diamond anvil cells near 90°with respect to the incident X-ray beam, is presented. The system offers double-sided on-axis heating by a single laser source and zero attenuation of incoming X-rays other than by the high-pressure environment. A description of the system, which has been tested for pressures above 100 GPa and temperatures up to 3000 K, is given. The XES spectra of laser-heated Mg0.67Fe0.33O demonstrate the potential to map the iron spin state in the pressure–temperature range of the Earth's lower mantle, and the NIS spectra of laser-heated FeSi give access to the sound velocity of this candidate of a phase inside the Earth's core. This portable system represents one of the few bridges across the gap between laser heating and high-resolution X-ray spectroscopies with signal collection near 90°.

The time evolution of the electron density and the resulting time dependence of the X-ray polarizability of a crystal irradiated by highly intense XFEL femtosecond pulses is investigated theoretically. Rate equations for bound electrons and the Boltzmann equation for the unbound electron gas are used in calculations.

Contributions of experimental and selected theoretical charge-density research to medicinal chemistry are reviewed; combining experimental methods from high-resolution small-molecule and macromolecular crystallography with theory proves to be fruitful.

Possibilities in auxiliary technique combinations with small- and wide-angle X ray scattering are described, as well as more complicated sample environments used in X-ray and neutron scattering.

Pressure can play a key role in probing the structure and dynamics of membrane assemblies, and is also critical to the biology and adaptation of deep-sea organisms. This article presents an overview of the effect of pressure on the structure of membranes and recent developments in high-pressure instrumentation.

It has been revealed that in cylindrical nano-confinement, the hydrogen-bonding direction of nylon-12 crystals in the rod could self-assemble to be parallel to the long axis of the rod. The dominant growth direction and hydrogen-bonding direction of the γ-form crystal in the long axis of the rod has been revealed by TEM–SAED and WAXD.

An expectation maximization algorithm is implemented to resolve the indexing ambiguity which arises when merging data from many crystals in protein crystallography, especially in cases where partial reflections are recorded in serial femtosecond crystallography (SFX) at XFELs.

Mammalian Munc18 proteins are essential for membrane fusion and human health. Here, we review the literature describing structural and in vitro data, and identify a possible explanation for the conflicting functional roles that have been reported.

A review of recent and ongoing development and results within the field of biological solution small-angle X-ray scattering (BioSAXS), with a focus on the increasing complexity of biological samples, data collection and data evaluation strategies.

The structure and function of dioxygenases in histone demethylation and DNA/RNA dimethylation are discussed.

The X-ray diffraction/X-ray fluorescence instrument CheMin on the Curiosity rover is a shoebox-sized device using transmission geometry and an energy-discriminating CCD detector. The instrument has returned the first X-ray diffraction data for soil and drilled samples from Mars outcrops, revealing a suite of primary basaltic minerals, amorphous components and varied hydrous alteration products including phyllosilicates.

Today, there is very little doubt that chemistry owes as much to crystallography as crystallography does to chemistry. This mutual synergy defines modern chemical crystallography.

Leading scientists set out resource challenge of meeting net zero emissions in the UK by 2050  The Natural History Museum

Biggest tremor on record at Little Plumpton site forces halt to fracking in Lancashire  Lancashire Evening Post

Coronavirus shock: Pandemic lockdowns have changed how the planet SOUNDS and vibrates  Express.co.uk

London soil pollution worst on former Blitz bomb sites  Chemistry World

UK's only active fracking site near Blackpool records largest ever earth tremor as homeowners complain of windows shaking  iNews

Did the quake shake you? Earth tremor felt in Shropshire  shropshirestar.com

Largest tremor yet detected at Lancashire fracking site  ITV News

Riddle of 'bang' in Birmingham intensifies as British Geological Survey issue statement  Birmingham Live

Somerset earthquake: Homes shaken by 3.2 magnitude tremor  BBC News

Did the earth move for you? British Geological Survey has asked if Cumbrians felt an earth tremor last week  News & Star

Solution structure of β-amylase 2 from Arabidopsis thaliana shows the role of the conserved N-terminus in enzyme tetramer formation.

The setup and operation of an industrial cryo-EM laboratory is described.

Sample preparation within single-particle cryo-electron microscopy can still be a significant bottleneck, with issues in reproducibility, ice quality and sample loss. New approaches have recently been reported that use spraying or pin printing instead of the traditional blotting approach. Here, experience in the use of different nozzle designs and spraying regimes is reported together with their influence on the resulting spray and grid quality.

The concept of statistical signal detection by controlling the false-discovery rate (FDR) to aid the atomic model interpretation of cryo-EM density maps is reviewed. The recommended usage of the FDR software tool is presented together with its successful integration into the CCP-EM suite.

The crystal structure of the c-type cytochrome NirC from Pseudomonas aeruginosa has been determined and reveals the simultaneous presence of monomers and 3D domain-swapped dimers in the same asymmetric unit.

This article presents an overview of the development of two basic software libraries for image manipulation and data visualization in cryo-EM: emcore and emvis.

The bond-valence method was performed on 51 crystal data sets from nitrogenase proteins, indicating the presence of molybdenum(III) in FeMo cofactors and vanadium(III) with more reduced iron complements in FeV cofactors.

The asymmetric unit of the title compound, C8H15N3S, contains two independent mol­ecules. In both mol­ecules, the seven-membered cyclo­heptane ring adopts a chair conformation. An intra­molecular N—H⋯N hydrogen bond is observed in both mol­ecules, forming S(5) graph-set motifs. In the crystal, the two independent mol­ecules are connected through N—H⋯S hydrogen bonds, forming dimers which are in turn further connected by N—H⋯S hydrogen bonds into chains along [010].

The title com­pound, C34H24O4S·0.5CH2Cl2, crystallizes with two independent mol­ecules and one di­chloro­methane solvent mol­ecule in the asymmetric unit. The crystal packing is consolidated by C—H⋯O hydrogen bonds.

The title 1,3,4-oxa­diazole derivative crystallizes as a hemihydrate, C8H6N2O2S·0.5H2O, with the water mol­ecule located on a twofold rotation axis. The 1,3,4-oxa­diazole mol­ecule is essentially planar, the r.m.s. deviation of the non-H atoms being 0.0443 Å. The dihedral angle between the mean planes of the phenyl and oxa­diazole rings is 6.101 (17)°. In the crystal, mol­ecules are linked via O—H⋯S and N—H⋯O hydrogen bonds involving the water mol­ecule, the N—H group and the thione S atom into undulating ribbons. Additional π–π inter­actions generate a two-dimensional supra­molecular framework extending parallel to (001).

The title hemihydrate, C12H9N5·0.5H2O, was isolated from the condensation reaction of quinoline-2-carbaldehyde with 4-amino-4H-1,2,4-triazole. The Schiff base mol­ecule adopts an E configuration about the C=N bond and is approximately planar, with a dihedral angle between the quinoline ring system and the 1,2,4-triazole ring of 12.2 (1)°. In the crystal, one water mol­ecule bridges two Schiff base mol­ecules via O—H⋯N hydrogen bonds. The Schiff base mol­ecules are inter­connected by π–π stacking inter­actions [centroid-centroid distances of 3.7486 (7) and 3.9003 (7) Å] into columns along [1overline{1}0].

The title Schiff base compound, C13H9ClN4O5·0.5CH3CN, crystallizes as an aceto­nitrile hemisolvate; the solvent mol­ecule being located on a twofold rotation axis. The mol­ecule is nearly planar, with a dihedral angle between the two benzene rings of 3.7 (2)°. The configuration about the C=N bond is E, and there is an intra­molecular N—H⋯Onitro hydrogen bond present forming an S(6) ring motif. In the crystal, mol­ecules are linked by O—H⋯O and N—H⋯O hydrogen bonds, forming layers lying parallel to (10overline{1}). The layers are linked by C—H⋯Cl hydrogen bonds, forming a supra­molecular framework. Within the framework there are offset π–π stacking inter­actions [inter­centroid distance = 3.833 (2) Å] present involving inversion-related mol­ecules. The DFT study shows that the HOMO and LUMO are localized in the plane extending from the phenol ring to the 2,4-di­nitro­benzene ring, and the HOMO–LUMO gap is found to be 0.13061 a.u.

The title compound, C15H13BrO2S, comprises three different substituents bound to a central (and chiral) methine-C atom, i.e. (4-bromo­phen­yl)sulfanyl, benzaldehyde and meth­oxy residues: crystal symmetry generates a racemic mixture. A twist in the mol­ecule is evident about the methine-C—C(carbon­yl) bond as evidenced by the O—C—C—O torsion angle of −20.8 (7)°. The dihedral angle between the bromo­benzene and phenyl rings is 43.2 (2)°, with the former disposed to lie over the oxygen atoms. The most prominent feature of the packing is the formation of helical supra­molecular chains as a result of methyl- and methine-C—H⋯O(carbon­yl) inter­actions. The chains assemble into a three-dimensional architecture without directional inter­actions between them. The nature of the weak points of contacts has been probed by a combination of Hirshfeld surface analysis, non-covalent inter­action plots and inter­action energy calculations. These point to the importance of weaker H⋯H and C—H⋯C inter­actions in the consolidation of the structure.

A new polymorph of the title compound, C10H13NO, was obtained by recrystallization of the commercial product from a water/ethanol mixture (1:1 v/v). Crystals of the previously reported racemic and homochiral forms of 2-phenyl­butyramide were grown from water–aceto­nitrile solution in 1:1 volume ratio [Khrustalev et al. (2014). Cryst. Growth Des. 14, 3360–3369]. While the previously reported racemic and enanti­opure forms of the title compound adopt very similar supra­molecular structures (hydrogen-bonded ribbons), the new racemic polymorph is stabilized by a single N—H⋯O hydrogen bond that links mol­ecules into chains along the c-axis direction with an anti­parallel (centrosymmetric) packing in the crystal. Hirshfeld mol­ecular surface analysis was employed to compare the inter­molecular inter­actions in the polymorphs of the title compound.

The asymmetric unit of the title compound, C12H22N+·CH3O3S−, consists of three (3,5-di­methyl­adamantan-1-yl)ammonium cations, C12H22N+, and three methane­sulfonate anions, CH3O3S−. In the crystal, the cations and anions associate via N—H⋯O hydrogen bonds into layers, parallel to the (001) plane, which include large supra­molecular hydrogen-bonded rings.