Errors in variable subscripts, equations and Fig. 8 in Section 3.2 of the article by Lotze et al. [(2024). J. Synchrotron Rad. 31, 42–52] are corrected.

Small-angle-scattering tensor tomography is a technique for studying anisotropic nanostructures of millimetre-sized samples in a volume-resolved manner. It requires the acquisition of data through repeated tomographic rotations about an axis which is subjected to a series of tilts. The tilt that can be achieved with a typical setup is geometrically constrained, which leads to limits in the set of directions from which the different parts of the reciprocal space map can be probed. Here, we characterize the impact of this limitation on reconstructions in terms of the missing wedge problem of tomography, by treating the problem of tensor tomography as the reconstruction of a three-dimensional field of functions on the unit sphere, represented by a grid of Gaussian radial basis functions. We then devise an acquisition scheme to obtain complete data by remounting the sample, which we apply to a sample of human trabecular bone. Performing tensor tomographic reconstructions of limited data sets as well as the complete data set, we further investigate and validate the missing wedge problem by investigating reconstruction errors due to data incompleteness across both real and reciprocal space. Finally, we carry out an analysis of orientations and derived scalar quantities, to quantify the impact of this missing wedge problem on a typical tensor tomographic analysis. We conclude that the effects of data incompleteness are consistent with the predicted impact of the missing wedge problem, and that the impact on tensor tomographic analysis is appreciable but limited, especially if precautions are taken. In particular, there is only limited impact on the means and relative anisotropies of the reconstructed reciprocal space maps.

An innovative dual-thickness semi-transparent beamstop designed to enhance the performance of small-angle X-ray scattering (SAXS) experiments is introduced. This design integrates two absorbers of differing thicknesses side by side into a single attenuator, known as a beamstop. Instead of completely stopping the direct beam, it attenuates it, allowing the SAXS detector to measure the transmitted beam through the sample. This approach achieves true synchronization in measuring both scattered and transmitted signals and effectively eliminates higher-order harmonic contributions when determining the transmission light intensity through the sample. This facilitates and optimizes signal detection and background subtraction. This contribution details the theoretical basis and practical implementation of this solution at the SAXS station on the 1W2A beamline at the Beijing Synchrotron Radiation Facility. It also anticipates its application at other SAXS stations, including that at the forthcoming High Energy Photon Source, providing an effective solution for high-precision SAXS experiments.

Starting from [Mn(C5H4Br)(PPh3)(CO)2] (1a), the cymantrenyl thio­ethers [Mn(C5H4SMe)(PPh3)(CO)2] (1b) and [Mn{C5H4–nBr(SMe)n}(PPh3)(CO)2] (n = 1 for com­pound 2, n = 2 for 3 and n = 3 for 4) were obtained, using either n-butyllithium (n-BuLi), lithium diiso­propyl­amide (LDA) or lithium tetra­methyl­piperidide (LiTMP) as base, followed by electrophilic quenching with MeSSMe. Stepwise consecutive reaction of [Mn(C5Br5)(PPh3)(CO)2] with n-BuLi and MeSSMe led finally to [Mn{C5(SMe)5}(PPh3)(CO)2] (11), only the fifth com­plex to be reported containing a perthiol­ated cyclo­penta­dienyl ring. The mol­ecular and crystal structures of 1b, 3, 4 and 11 were determined and were studied for the occurrence of S⋯S and S⋯Br inter­actions. It turned out that although some inter­actions of this type occurred, they were of minor importance for the arrangement of the mol­ecules in the crystal.

The title compound, 3-[(benzo-1,3-dioxol-5-yl)amino]-4-meth­oxy­cyclo­but-3-ene-1,2-dione, C12H9NO5 (3), is a precursor to an anti­mycobacterial squaramide. Block-shaped crystals of a monoclinic form (3-I, space group P21/c, Z = 8, Z' = 2) and needle-shaped crystals of a triclinic form (3-II, space group P-1, Z = 4, Z' = 2) were found to crystallize concomitantly. In both crystal forms, R22(10) dimers assemble through N—H⋯O=C hydrogen bonds. These dimers are formed from crystallographically unique mol­ecules in 3-I, but exhibit crystallographic Ci symmetry in 3-II. Twinning by pseudomerohedry was encountered in the crystals of 3-II. The conformations of 3 in the solid forms 3-I and 3-II are different from one another but are similar for the unique mol­ecules in each polymorph. Density functional theory (DFT) calculations on the free mol­ecule of 3 indicate that a nearly planar conformation is preferred.

CdaA is the most widespread diadenylate cyclase in many bacterial species, including several multidrug-resistant human pathogens. The enzymatic product of CdaA, cyclic di-AMP, is a secondary messenger that is essential for the viability of many bacteria. Its absence in humans makes CdaA a very promising and attractive target for the development of new antibiotics. Here, the structural results are presented of a crystallographic fragment screen against CdaA from Listeria monocytogenes, a saprophytic Gram-positive bacterium and an opportunistic food-borne pathogen that can cause listeriosis in humans and animals. Two of the eight fragment molecules reported here were localized in the highly conserved ATP-binding site. These fragments could serve as potential starting points for the development of antibiotics against several CdaA-dependent bacterial species.

The determination of the atomic resolution structure of biomacromolecules is essential for understanding details of their function. Traditionally, such a structure determination has been performed with crystallographic or nuclear resonance methods, but during the last decade, cryogenic transmission electron microscopy (cryo-TEM) has become an equally important tool. As the blotting and flash-freezing of the samples can induce conformational changes, external validation tools are required to ensure that the vitrified samples are representative of the solution. Although many validation tools have already been developed, most of them rely on fully resolved atomic models, which prevents early screening of the cryo-TEM maps. Here, a novel and automated method for performing such a validation utilizing small-angle X-ray scattering measurements, publicly available through the new software package AUSAXS, is introduced and implemented. The method has been tested on both simulated and experimental data, where it was shown to work remarkably well as a validation tool. The method provides a dummy atomic model derived from the EM map which best represents the solution structure.

Here, a machine-learning method based on a kinetically informed neural network (NN) is introduced. The proposed method is designed to analyze a time series of difference electron-density maps from a time-resolved X-ray crystallographic experiment. The method is named KINNTREX (kinetics-informed NN for time-resolved X-ray crystallography). To validate KINNTREX, multiple realistic scenarios were simulated with increasing levels of complexity. For the simulations, time-resolved X-ray data were generated that mimic data collected from the photocycle of the photoactive yellow protein. KINNTREX only requires the number of intermediates and approximate relaxation times (both obtained from a singular valued decomposition) and does not require an assumption of a candidate mechanism. It successfully predicts a consistent chemical kinetic mechanism, together with difference electron-density maps of the intermediates that appear during the reaction. These features make KINNTREX attractive for tackling a wide range of biomolecular questions. In addition, the versatility of KINNTREX can inspire more NN-based applications to time-resolved data from biological macromolecules obtained by other methods.

Immunodominant membrane protein (IMP) is a prevalent membrane protein in phytoplasma and has been confirmed to be an F-actin-binding protein. However, the intricate molecular mechanisms that govern the function of IMP require further elucidation. In this study, the X-ray crystallographic structure of IMP was determined and insights into its interaction with plant actin are provided. A comparative analysis with other proteins demonstrates that IMP shares structural homology with talin rod domain-containing protein 1 (TLNRD1), which also functions as an F-actin-binding protein. Subsequent molecular-docking studies of IMP and F-actin reveal that they possess complementary surfaces, suggesting a stable interaction. The low potential energy and high confidence score of the IMP–F-actin binding model indicate stable binding. Additionally, by employing immunoprecipitation and mass spectrometry, it was discovered that IMP serves as an interaction partner for the phytoplasmal effector causing phyllody 1 (PHYL1). It was then shown that both IMP and PHYL1 are highly expressed in the S2 stage of peanut witches' broom phytoplasma-infected Catharanthus roseus. The association between IMP and PHYL1 is substantiated through in vivo immunoprecipitation, an in vitro cross-linking assay and molecular-docking analysis. Collectively, these findings expand the current understanding of IMP interactions and enhance the comprehension of the interaction of IMP with plant F-actin. They also unveil a novel interaction pathway that may influence phytoplasma pathogenicity and host plant responses related to PHYL1. This discovery could pave the way for the development of new strategies to overcome phytoplasma-related plant diseases.

To date, accurate modelling of the solvation process is challenging, often over-simplifying the solvent–solute interactions. The interplay between the molecular arrangement associated with the solvation process and crystal nucleation has been investigated by analysis of the piezo-solvatochromic behaviour of Reichardt's dye, ET(1), in methanol, ethanol and acetone under high pressure. High-pressure single-crystal X-ray diffraction and UV–Vis spectroscopy reveal the impact of solute–solvent interactions on the optical properties of ET(1). The study underscores the intricate relationship between solvent properties, molecular conformation and crystal packing. The connection between liquid and solid phases emphasizes the capabilities of high-pressure methods for expanding the field of crystal engineering. The high-pressure environment allowed the determination of the crystal structures reported here that are built from organic molecules fourfold solvated with ethanol or methanol: ET(1)·4CH3OH and ET(1)·4C2H5OH·H2O. The observed piezo-solvatochromic effects highlight the potential of ET(1) in nonlinear optoelectronics and expand the application of solvatochromic chemical indicators to pressure sensors.

Stimulated by informal conversations at the XVII International Small Angle Scattering (SAS) conference (Traverse City, 2017), an international team of experts undertook a round-robin exercise to produce a large dataset from proteins under standard solution conditions. These data were used to generate consensus SAS profiles for xylose isomerase, urate oxidase, xylanase, lysozyme and ribonuclease A. Here, we apply a new protocol using maximum likelihood with a larger number of the contributed datasets to generate improved consensus profiles. We investigate the fits of these profiles to predicted profiles from atomic coordinates that incorporate different models to account for the contribution to the scattering of water molecules of hydration surrounding proteins in solution. Programs using an implicit, shell-type hydration layer generally optimize fits to experimental data with the aid of two parameters that adjust the volume of the bulk solvent excluded by the protein and the contrast of the hydration layer. For these models, we found the error-weighted residual differences between the model and the experiment generally reflected the subsidiary maxima and minima in the consensus profiles that are determined by the size of the protein plus the hydration layer. By comparison, all-atom solute and solvent molecular dynamics (MD) simulations are without the benefit of adjustable parameters and, nonetheless, they yielded at least equally good fits with residual differences that are less reflective of the structure in the consensus profile. Further, where MD simulations accounted for the precise solvent composition of the experiment, specifically the inclusion of ions, the modelled radius of gyration values were significantly closer to the experiment. The power of adjustable parameters to mask real differences between a model and the structure present in solution is demonstrated by the results for the conformationally dynamic ribonuclease A and calculations with pseudo-experimental data. This study shows that, while methods invoking an implicit hydration layer have the unequivocal advantage of speed, care is needed to understand the influence of the adjustable parameters. All-atom solute and solvent MD simulations are slower but are less susceptible to false positives, and can account for thermal fluctuations in atomic positions, and more accurately represent the water molecules of hydration that contribute to the scattering profile.

Owing to their exceptional properties, hard materials such as advanced ceramics, metals and composites have enormous economic and societal value, with applications across numerous industries. Understanding their microstructural characteristics is crucial for enhancing their performance, materials development and unleashing their potential for future innovative applications. However, their microstructures are unambiguously hierarchical and typically span several length scales, from sub-ångstrom to micrometres, posing demanding challenges for their characterization, especially for in situ characterization which is critical to understanding the kinetic processes controlling microstructure formation. This review provides a comprehensive description of the rapidly developing technique of ultra-small angle X-ray scattering (USAXS), a nondestructive method for probing the nano-to-micrometre scale features of hard materials. USAXS and its complementary techniques, when developed for and applied to hard materials, offer valuable insights into their porosity, grain size, phase composition and inhomogeneities. We discuss the fundamental principles, instrumentation, advantages, challenges and global status of USAXS for hard materials. Using selected examples, we demonstrate the potential of this technique for unveiling the microstructural characteristics of hard materials and its relevance to advanced materials development and manufacturing process optimization. We also provide our perspective on the opportunities and challenges for the continued development of USAXS, including multimodal characterization, coherent scattering, time-resolved studies, machine learning and autonomous experiments. Our goal is to stimulate further implementation and exploration of USAXS techniques and inspire their broader adoption across various domains of hard materials science, thereby driving the field toward discoveries and further developments.

K3FeTe2O8(OH)2(H2O)2 was synthesized under hydrothermal conditions from Te(OH)6, FeSO4·7H2O and 85 wt% KOH in a 1:2:6 molar ratio. The crystal structure is built of a triperiodic network. One disordered water molecule per formula unit is located in a channel and can be partially removed by heating. Systematic one-dimensional diffuse scattering indicates a polytypic character, which is best described by application of the order–disorder theory. The major polytype is monoclinic with pseudo-orthorhombic metrics. It is interrupted by fragments of an orthorhombic polytype. The diffraction intensities are analyzed using structure factor calculations.

In the course of an investigation of the supramolecular behaviour of copper(II) complexes with the 5-phenyl­imidazole/perchlorate ligand system (`blend') remarkable solvatomorphism has been observed. By employing a variety of crystallization solvents (polar protic, polar/non-polar aprotic), a series of 12 crystalline solvatomorphs with the general formula [Cu(ClO4)2(LH)4]·x(solvent) have been obtained [LH = 5-phenyl­imidazole, x(solvent) = 3.3(H2O) (1), 2(methanol) (2), 2(ethanol) (3), 2(1-propanol) (4), 2(2-propanol) (5), 2(2-butanol) (6), 2(di­methyl­formamide) (7), 2(acetone) (8), 2(tetra­hydro­furane) (9), 2(1,4-dioxane) (10), 2(ethyl acetate) (11) and 1(di­ethyl ether) (12)]. The structures have been solved using single-crystal X-ray diffraction and the complexes were characterized by thermal analysis and infrared spectroscopy. The solvatomorphs are isostructural (triclinic, P1), with the exception of compound 9 (monoclinic, P21/n). The supramolecular structures and the role of the various solvents is discussed. All potential hydrogen-bond functionalities, both of the [Cu(ClO4)2(LH)4] units and of the solvents, are utilized in the course of the crystallization process. The supramolecular assembly in all structures is directed by strong recurring Nimidazole–H⋯Operchlorate motifs leading to robust scaffolds composed of the [Cu(ClO4)2(LH)4] host complexes. The solvents are located in channels and, with the exception of the disordered waters in 1 and the di­ethyl ether in 12, participate in hydrogen-bonding formation with the [Cu(ClO4)2(LH)4] complexes, serving as both hydrogen-bond acceptors and donors (for the polar protic solvents in 2–6), or solely as hydrogen-bond acceptors (for the polar/non-polar aprotic solvents in 7–11), linking the complexes and contributing to the stability of the crystalline compounds.

A polycrystalline sample LuCrO3 has been characterized by neutron powder diffraction (NPD) and magnetization measurements. Its crystal structure has been Rietveld refined from NPD data in space group Pnma; this perovskite contains strongly tilted CrO6 octahedra with extremely bent Cr—O—Cr superexchange angles of ∼142°. The NPD data show that below Néel temperature (TN ≃ 131 K), the magnetic structure can be defined as an A-type antiferromagnetic arrangement of Cr3+ magnetic moments, aligned along the b axis, with a canting along the c axis. A noticeable magneto­strictive effect is observed in the unit-cell parameters and volume upon cooling down across TN. The AC magnetic susceptibility indicates the onset of magnetic ordering below 112.6 K; the magnetization isotherms below TN show a nonlinear behaviour that is associated with the described canting of the Cr3+ magnetic moments. From the Curie–Weiss law, the effective moment of the Cr3+ sublattice is found to be μeff = 3.55 μB (calculated 3.7 μB) while the ΘCW parameter yields a value of −155 K, indicating antiferromagnetic interactions. There is a conspicuous increase of TN upon the application of external pressure, which must be due to shortening of the Cr—O bond length under compression that increases the orbital overlap integral.

The embedded call to a special version of the web-based Bilbao Crystallographic Server tool k-SUBGROUPSMAG from within GSAS-II to form a list of all possible commensurate magnetic subgroups of a parent magnetic grey group is described. It facilitates the selection and refinement of the best commensurate magnetic structure model by having all the analysis tools including Rietveld refinement in one place as part of GSAS-II. It also provides the chosen magnetic space group as one of the 1421 possible standard Belov–Neronova–Smirnova forms or equivalent non-standard versions.

The re-investigation of [Bi2O2(OH)](NO3), dioxidodibismuth(III) hydroxide nitrate, on the basis of single-crystal X-ray diffraction data revealed an apparent structural phase transition of a crystal structure determined previously (space group Cmc21 at 173 K) to a crystal structure with lower symmetry (space group Pna21 at 100 K). The Cmc21 → Pna21 group–subgroup relationship between the two crystal structures is klassengleiche with index 2. In contrast to the crystal structure in Cmc21 with orientational disorder of the nitrate anion, disorder does not occur in the Pna21 structure. Apart from the disorder of the nitrate anion, the general structural set-up in the two crystal structures is very similar: [Bi2O2]2+ layers extend parallel to (001) and alternate with layers of (OH)− anions above and (NO3)− anions below the cationic layer. Whereas the (OH)− anion shows strong bonds to the BiIII cations, the (NO3)− anion weakly binds to the BiIII cations of the cationic layer. A rather weak O—H⋯O hydrogen-bonding inter­action between the (OH)− anion and the (NO3)− anion links adjacent sheets along [001].

BioXTAS RAW is a free open-source program for reduction, analysis and modelling of biological small-angle scattering data. Here, the new developments in RAW version 2 are described. These include improved data reduction using pyFAI; updated automated Guinier fitting and Dmax finding algorithms; automated series (e.g. size-exclusion chromatography coupled small-angle X-ray scattering or SEC-SAXS) buffer- and sample-region finding algorithms; linear and integral baseline correction for series; deconvolution of series data using regularized alternating least squares (REGALS); creation of electron-density reconstructions using electron density via solution scattering (DENSS); a comparison window showing residuals, ratios and statistical comparisons between profiles; and generation of PDF reports with summary plots and tables for all analysis. Furthermore, there is now a RAW API, which can be used without the graphical user interface (GUI), providing full access to all of the functionality found in the GUI. In addition to these new capabilities, RAW has undergone significant technical updates, such as adding Python 3 compatibility, and has entirely new documentation available both online and in the program.

A multi-slit very small angle neutron scattering (MS-VSANS) instrument has been finally accepted at the China Spallation Neutron Source (CSNS). It is the first spallation neutron source based VSANS instrument. MS-VSANS has a good signal-to-noise ratio and can cover a wide scattering vector magnitude range from 0.00028 to 1.4 Å−1. In its primary flight path, a combined curved multichannel beam bender and sections of rotary exchange drums are installed to minimize the background downstream of the instrument. An exchangeable multi-slit beam focusing system is integrated into the primary flight path, enabling access to a minimum scattering vector magnitude of 0.00028 Å−1. MS-VSANS has three modes, namely conventional SANS, polarizing SANS and VSANS modes. In the SANS mode, three motorized high-efficiency 3He tube detectors inside the detector tank cover scattering angles from 0.12 to 35° simultaneously. In the polarizing SANS mode, a double-V cavity provides highly polarized neutrons and a high-efficiency 3He polarization analyser allows full polarization analysis. In the VSANS mode, an innovative high-resolution gas electron multiplier detector covers scattering angles from 0.016 to 0.447°. The absolute scattering intensities of a selection of standard samples are obtained using the direct-beam technique; the effectiveness of this method is verified by testing the standard samples and comparing the results with those from a benchmark instrument. The MS-VSANS instrument is designed to be flexible and versatile and all the design goals have been achieved.

Analysis of small-angle scattering (SAS) data requires intensive modeling to infer and characterize the structures present in a sample. This iterative improvement of models is a time-consuming process. Presented here is Scattering Equation Builder (SEB), a C++ library that derives exact analytic expressions for the form factors of complex composite structures. The user writes a small program that specifies how the sub-units should be linked to form a composite structure and calls SEB to obtain an expression for the form factor. SEB supports e.g. Gaussian polymer chains and loops, thin rods and circles, solid spheres, spherical shells and cylinders, and many different options for how these can be linked together. The formalism behind SEB is presented and simple case studies are given, such as block copolymers with different types of linkage, as well as more complex examples, such as a random walk model of 100 linked sub-units, dendrimers, polymers and rods attached to the surfaces of geometric objects, and finally the scattering from a linear chain of five stars, where each star is built up of four diblock copolymers. These examples illustrate how SEB can be used to develop complex models and hence reduce the cost of analyzing SAS data.

This article describes a correction procedure for the removal of indirect background contributions to measured small-angle X-ray scattering patterns. The high scattering power of a sample in the ultra-small-angle region may serve as a secondary source for a window placed in front of the detector. The resulting secondary scattering appears as a sample-dependent background in the measured pattern that cannot be directly subtracted. This is an intricate problem in measurements at ultra-low angles, which can significantly reduce the useful dynamic range of detection. Two different procedures are presented to retrieve the real scattering profile of the sample.

Small-angle scattering (SAS) is a key experimental technique for analyzing nanoscale structures in various materials. In SAS data analysis, selecting an appropriate mathematical model for the scattering intensity is critical, as it generates a hypothesis of the structure of the experimental sample. Traditional model selection methods either rely on qualitative approaches or are prone to overfitting. This paper introduces an analytical method that applies Bayesian model selection to SAS measurement data, enabling a quantitative evaluation of the validity of mathematical models. The performance of the method is assessed through numerical experiments using artificial data for multicomponent spherical materials, demonstrating that this proposed analysis approach yields highly accurate and interpretable results. The ability of the method to analyze a range of mixing ratios and particle size ratios for mixed components is also discussed, along with its precision in model evaluation by the degree of fitting. The proposed method effectively facilitates quantitative analysis of nanoscale sample structures in SAS, which has traditionally been challenging, and is expected to contribute significantly to advancements in a wide range of fields.

Small-angle X-ray tensor tomography and the related wide-angle X-ray tensor tomography are X-ray imaging techniques that tomographically reconstruct the anisotropic scattering density of extended samples. In previous studies, these methods have been used to image samples where the scattering density depends slowly on the direction of scattering, typically modeling the directionality, i.e. the texture, with a spherical harmonics expansion up until order ℓ = 8 or lower. This study investigates the performance of several established algorithms from small-angle X-ray tensor tomography on samples with a faster variation as a function of scattering direction and compares their expected and achieved performance. The various algorithms are tested using wide-angle scattering data from an as-drawn steel wire with known texture to establish the viability of the tensor tomography approach for such samples and to compare the performance of existing algorithms.

For a reliable characterization of materials and systems featuring multiple structural levels, a broad length scale from a few ångström to hundreds of nanometres must be analyzed and an extended Q range must be covered in X-ray and neutron scattering experiments. For certain samples or effects, it is advantageous to perform such characterization with a single instrument. Neutrons offer the unique advantage of contrast variation and matching by D-labeling, which is of great value in the characterization of natural or synthetic polymers. Some time-of-flight small-angle neutron scattering (TOF-SANS) instruments at neutron spallation sources can cover an extended Q range by using a broad wavelength band and a multitude of detectors. The detectors are arranged to cover a wide range of scattering angles with a resolution that allows both large-scale morphology and crystalline structure to be resolved simultaneously. However, for such analyses, the SANS instruments at steady-state sources operating in conventional monochromatic pinhole mode rely on additional wide-angle neutron scattering (WANS) detectors. The resolution must be tuned via a system of choppers and a TOF data acquisition option to reliably measure the atomic to mesoscale structures. The KWS-2 SANS diffractometer at Jülich Centre for Neutron Science allows the exploration of a wide Q range using conventional pinhole and lens focusing modes and an adjustable resolution Δλ/λ between 2 and 20%. This is achieved through the use of a versatile mechanical velocity selector combined with a variable slit opening and rotation frequency chopper. The installation of WANS detectors planned on the instrument required a detailed analysis of the quality of the data measured over a wide angular range with variable resolution. This article presents an assessment of the WANS performance by comparison with a McStas [Willendrup, Farhi & Lefmann (2004). Physica B, 350, E735–E737] simulation of ideal experimental conditions at the instrument.

Geological formations provide a promising environment for the long-term and short-term storage of gases, including carbon dioxide, hydrogen and hydro­carbons, controlled by the rock-specific small-scale pore structure. This study investigates the nanoscale structure and gas uptake in a highly porous silica aerogel (a synthetic proxy for natural rocks) using transmission electron microscopy, X-ray diffraction, and small-angle and ultra-small-angle neutron scattering with a tracer of deuterated methane (CD4) at pressures up to 1000 bar. The results show that the adsorption of CD4 in the porous silica matrix is scale dependent. The pore space of the silica aerogel is fully accessible to the invading gas, which quickly equilibrates with the external pressure and shows no condensation on the sub-nanometre scale. In the 2.5–50 nm pore size region a classical two-phase adsorption behaviour is observed. The structure of the aerogel returns to its original state after the CD4 pressure has been released.

X-ray scattering has become a major tool in the structural characterization of nanoscale materials. Thanks to the widely available experimental and computational atomic models, coordinate-based X-ray scattering simulation has played a crucial role in data interpretation in the past two decades. However, simulation of real-space pair distance distribution functions (PDDFs) from small- and wide-angle X-ray scattering, SAXS/WAXS, has been relatively less exploited. This study presents a comparison of PDDF simulation methods, which are applied to molecular structures that range in size from β-cyclo­dextrin [1 kDa molecular weight (MW), 66 non-hydrogen atoms] to the satellite tobacco mosaic virus capsid (1.1 MDa MW, 81 960 non-hydrogen atoms). The results demonstrate the power of interpretation of experimental SAXS/WAXS from the real-space view, particularly by providing a more intuitive method for understanding of partial structure contributions. Furthermore, the computational efficiency of PDDF simulation algorithms makes them attractive as approaches for the analysis of large nanoscale materials and biological assemblies. The simulation methods demonstrated in this article have been implemented in stand-alone software, SolX 3.0, which is available to download from https://12idb.xray.aps.anl.gov/solx.html.

The Q resolution in Bonse–Hart double-crystal diffractometers is determined for a given Bragg angle by the value of the crystallographic structure factor. To date, the reflections Si 220 or Si 111 have been used exclusively in neutron scattering, which provide resolutions for triple-bounce crystals of about 2 × 10−5 Å−1 (FWHM). The Darwin width of the GaAs 200 reflection is about a factor of 10 smaller, offering the possibility of a Q resolution of 2 × 10−6 Å−1 provided crystals of sufficient quality are available. This article reports a feasibility study with single-bounce GaAs 200, yielding a Q resolution of 4.6 × 10−6 Å−1, six times superior in comparison with a Si 220 setup.

Small-angle neutron scattering is a widely used technique to study large-scale structures in bulk samples. The largest accessible length scale in conventional Bragg scattering is determined by the combination of the longest available neutron wavelength and smallest resolvable scattering angle. A method is presented that circumvents this limitation and is able to extract larger length scales from the low-q power-law scattering using a modification of the well known Porod law connecting the scattered intensity of randomly distributed objects to their specific surface area. It is shown that in the special case of a highly aligned domain structure the specific surface area extracted from the modified Porod law can be used to determine specific length scales of the domain structure. The analysis method is applied to study the micrometre-sized domain structure found in the intermediate mixed state of the superconductor niobium. The analysis approach allows the range of accessible length scales to be extended from 1 µm to up to 40 µm using a conventional small-angle neutron scattering setup.

Here, a morphologically based approach is used for the in situ characterization of 3D growth rates of facetted crystals from the solution phase. Crystal images of single crystals of the β-form of l-glutamic acid are captured in situ during their growth at a relative supersaturation of 1.05 using transmission optical microscopy. The crystal growth rates estimated for both the {101} capping and {021} prismatic faces through image processing are consistent with those determined using reflection light mode [Jiang, Ma, Hazlehurst, Ilett, Jackson, Hogg & Roberts (2024). Cryst. Growth Des. 24, 3277–3288]. The growth rate in the {010} face is, for the first time, estimated from the shadow widths of the {021} prismatic faces and found to be typically about half that of the {021} prismatic faces. Analysis of the 3D shape during growth reveals that the initial needle-like crystal morphology develops during the growth process to become more tabular, associated with the Zingg factor evolving from 2.9 to 1.7 (>1). The change in relative solution supersaturation during the growth process is estimated from calculations of the crystal volume, offering an alternative approach to determine this dynamically from visual observations.

Presented here is an effective approach to desmearing slit ultra-small-angle neutron scattering (USANS) data, based on complementary small-angle neutron scattering (SANS) measurements, leading to a seamless merging of these data sets. The study focuses on the methodological aspects of desmearing USANS data, which can then be presented in the conventional manner of SANS, enabling a broader pool of data analysis methods. The key innovation lies in the use of smeared SANS data for extrapolating slit USANS, offering a self-consistent integrand function for desmearing with Lake's iterative method. The proposed approach is validated through experimental data on porous anodized aluminium oxide membranes, showcasing its applicability and benefits. The findings emphasize the importance of accurate desmearing for merging USANS and SANS data in the crossover q region, which is particularly crucial for complex scattering patterns.

The design and first results of a high-transmission soft X-ray spectrometer operated at the X-SPEC double-undulator beamline of the KIT Light Source are presented. As a unique feature, particular emphasis was placed on optimizing the spectrometer transmission by maximizing the solid angle and the efficiencies of spectrometer gratings and detector. A CMOS detector, optimized for soft X-rays, allows for quantum efficiencies of 90% or above over the full energy range of the spectrometer, while simultaneously offering short readout times. Combining an optimized control system at the X-SPEC beamline with continuous energy scans (as opposed to step scans), the high transmission of the spectrometer, and the fast readout of the CMOS camera, enable the collection of entire rapid resonant inelastic soft X-ray scattering maps in less than 1 min. Series of spectra at a fixed energy can be taken with a frequency of up to 5 Hz. Furthermore, the use of higher-order reflections allows a very wide energy range (45 to 2000 eV) to be covered with only two blazed gratings, while keeping the efficiency high and the resolving power E/ΔE above 1500 and 3000 with low- and high-energy gratings, respectively.

Germany-based fintech MODIFI has announced...

"Red Band Society," premieres on Fox September 17th, starring Octavia Spencer, Charlie Rowe and Nolan Sotillo.; Credit: Fox Television Studios

The Los Angeles County Metropolitan Transportation Authority is pulling ads for the Fox television show "Red Band Society" from nearly 200 buses amid complaints they are racist and offensive to women.

The ads show the ensemble cast's members in front of a wall with graffiti describing their characters.

A denigrating word for a woman is used to describe the show's star, Octavia Spencer's character.

The Los Angeles Times reports transit officials began pulling the ads on Wednesday. They had been up for five weeks.

The Red Band Society also shared the ad on its Facebook page in August. 

Facebook: #RedBandSociety ad

But it's since edited it to look like this.

Photo: New ad via Facebook

Protesters who attended Thursday's transit agency board meeting complained the depiction of Spencer's character is racist and offensive to women.

The actress, who plays a nurse in the hospital drama, is black.

She won a supporting actress Oscar for her role in "The Help."

Lisa Emery, left, and Lois Smith are in the world premiere of Jordan Harrison’s “Marjorie Prime” at the Center Theatre Group/Mark Taper Forum. ; Credit: Craig Schwartz

Lois Smith has had a long and varied acting career. She made her Broadway debut in 1952 and three years later was cast opposite James Dean in “East of Eden.” She was in “Five Easy Pieces” with Jack Nicholson and — more recently — she had a role on HBO’s “True Blood.”

Now, the 83-year-old Smith is starring at the Mark Taper Forum in the world premiere of “Marjorie Prime” — a play by Jordan Harrison about aging, memory and artificial intelligence.

Smith spoke with The Frame's John Horn about the play and her role.

Interview Highlights

Smith on how "Marjorie Prime" addresses the notion of memory

"One character at some point says, 'I don't know what memory's made of. Is it sedimentary layers?' The play [is] not a meditation, but a riff, perhaps, on that subject. Jordan [Harrison, the playwright] said at some point, 'This play is the intersection of perhaps humanity and technology.' The play takes place a bit in the future. Not a long time — we'll all recognize ourselves very well — but that's one of its surprises."

Smith on the evolution of becoming a character

"It's been extremely interesting. I suppose in every play [the process] deepens and stretches out. This one, no doubt about it...it's elusive in a lot of ways and I think, 'Oh good, I'm getting there, I'm finding out.' And then I think, 'Oh, farther to go.'" 

Smith on how audience members of different ages react to the play's take on aging

"One friend saw it in regards to [her] mother, who's becoming forgetful. [That] mother saw her own very aged father. They laughed about what they each brought up, because they had just been sitting at the same performance of the same play."

Smith on her role, which isn't too physically taxing

"I'm not doing much walking around. I walk on, I walk off, I walk on — and that's about it. I sometimes say, 'It's almost as good as a bed part,' because I spend time in a recliner, which is pretty nice."

Kevin Smith with a room full of his own strain of pot, created for his new film, "Tusk." ; Credit: James Kim/KPCC

When Kevin Smith records his podcast, Smodcast, he says, "I'm usually blazed." Which, if you've heard the episode where Smith comes up with the entire story for his new film, "Tusk," it should come as no surprise.

The film is about a man who takes another man hostage and turns him into a walrus. While the movie itself doesn't mention or include any weed, Smith thought medical marijuana would be a nice complement to the viewing experience. 

A24, the film distribution company, came to Smith with a marketing idea: create strains of weed for the film. Smith thought it was genius. Buds and Roses — a cannabis dispensary in Studio City — was approached by Smith and his team to make medical marijuana specifically for the film. The dispensary came up with two strains called "Mr. Tusk" and "White Walrus." 

We met up with the director at Buds and Roses to see why the green substance was a perfect pairing for the film: 

Interview Highlights:

Smith knows that some people enjoy going to the movies stoned: 

"This movie, out of all movies, seems like a real head trip of a flick. So if they have their medical marijuana card, by all means, enjoy the movie. Don't feel the need to go back if you don't remember anything. It's not a gimmick to make them go twice or anything. But in a world where people are gonna smoke medicinal marijuana, having a 'Tusk' sticker on there just makes me smile. Kind of makes sense for this movie." 

How Fleetwood Mac and weed helped his writing:

"I put on Fleetwood Mac's 'Tusk' over and over on repeat and would just sit there and blaze while I wrote. And you know, I blaze in the way that I used to smoke cigarettes. So, I'll light it and put it in an ashtray, let it burn and stuff. So it fills the room like incense if you will. But, yeah, for a movie like 'Tusk,' I guess you gotta be pretty stoned to make the guy-who-makes-a-guy-into-a-walrus movie. And I'm kinda glad I did. It's weird. People are calling it the best movie I've ever made and I was like, 'Well, this is the only one I made stoned.' So I'm like, 'Guess what I'm doing, kids!'"

Smith used to be against drugs: 

"I smoked weed in my life, but I would never consider myself a stoner. In fact, I still had the '80s [attitude] lingering, 'Just say no,' and,  you know, 'Oh my lord! It's a drug!' It wasn't until I became older — age 38 — when I started smoking weed on a regular basis. I was like, 'This is not a drug. This is ridiculous! It grows in the Earth.' So once I got past the bias that was pounded into us in the '80s, suddenly I was like, 'Heavens. I like who I am here.' It doesn't make you a better person, kids. It doesn't make you more creative. What it does is it kind of knocks fear on its ass. You face your fears a little better." 

Disclaimer: Smith wants you to know that he does not endorse marijuana for anyone under 21:

"Kids, teenagers... I'm talking to you. The teenage brain is stunted by marijuana smoking so you guys have to wait 'til you're older. I didn't start smoking 'til I was 38 years old. I'm not saying wait 'til then. That was a stupid mistake on my behalf. But wait until you're legit. Wait until you're 21 before you start smoking." 

The general equation of the δ direct methods is established and applied in its difference form to the definition of one of the two residuals that constitute the SMAR phasing algorithm. These two residuals use the absolute value of ρ and/or the zero conversion of negative Fourier ripples (≥50% of the unit-cell volume). Alternatively, when solved for ρ, the general equation provides a simple derivation of the already known δM tangent formula.

Lithuania-based iDenfy has introduced an AI-powered Data Crossmatch feature aimed at improving the Know Your Business (KYB) compliance process.

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; Credit: /Katherine Du

Over the years, NPR's poetry community has turned both painful and joyful experiences into magnificent work.

As the world still endures the coronavirus pandemic, the U.S. also grieves over increased violence against Asian Americans and a mass shooting in Georgia that left six women of Asian descent dead.

"Let's be clear: Anti-Asian violence and discrimination are not new. But, this racism seems to be heightened," says Kwame Alexander, NPR's resident poet. "And the onus is not on Asian Americans to figure this out. Frankly, it's on white people, it's on the rest of us — individually, systemically, to talk about it, to pay attention to, advocate against it."

"Between Autumn Equinox and Winter Solstice, Today," by Emily Jungmin Yoon, is a list poem that reflects the coldness of the world and how it wears on us. Yoon is a South Korean-born poet pursuing her Ph.D. in Korean literature at the University of Chicago.

Alexander and Morning Edition's Rachel Martin ask listeners: How do you cope with recent anti-Asian violence and discrimination? Tell us in a list poem.

Your poem doesn't have to rhyme. It just needs to have an ordered list with details that show your state of mind — and must begin with the word "today."

Share your poem through the form below. Then Alexander will take lines from some of your pieces and create a community crowdsourced poem. Alexander and Martin will read it on air, and NPR will publish it online, where contributors will be credited.

Submissions are due by noon ET on Monday, April 5.

Here are the terms of the callout:

By providing your Submission to us, you agree that you have read, understand and accept the following terms in relation to the content and information (your "Submission") you are providing to National Public Radio ("NPR," "us" or "our"):

You are submitting content pursuant to a callout by Morning Edition related to a segment with Kwame Alexander wherein he creates unique poetry based on listener submissions. You understand that you are submitting content for the purpose of having Kwame use that content to create a new poem or poems ("Poem") with the material you submit. You must be over the age of 18 to submit material.

You will retain copyright in your Submission, but agree that NPR and/or Kwame Alexander may edit, modify, use, excerpt, publish, adapt or otherwise make derivative works from your Submission and use your Submission or derivative works in whole or in part in any media or format and/or use the Submission or Poem for journalistic and/or promotional purposes generally, and may allow others to do so. You understand that the Poem created by Kwame Alexander will be a new creative work and may be distributed through NPR's programs (or other media), and the Poem and programs can be separately subject to copyright protection. Your Submission does not plagiarize or otherwise infringe any third-party copyright, moral rights or any other intellectual property rights or similar rights. You have not copied any part of your Submission from another source. If your Submission is selected for inclusion in the Poem, you will be acknowledged in a list of contributors on NPR's website or otherwise receive appropriate credit, but failure to do so shall not be deemed a breach of your rights.

Your submission will be governed by our general Terms of Use and Privacy Policy. As the Privacy Policy says, we want you to be aware that there may be circumstances in which the exemptions provided under law for journalistic activities or freedom of expression may override privacy rights you might otherwise have.

This content is from Southern California Public Radio. View the original story at SCPR.org.

Cars make their way toward downtown Los Angeles on April 22. California could regain the right to set its own vehicle emissions standards after the Environmental Protection Agency announced it was moving to curb a Trump-era policy that sought to erode the state's previously-held power.; Credit: Mario Tama/Getty Images

The Environmental Protection Agency (EPA) said on Monday it is preparing to restore California's right to set its own vehicle emissions standards, in a widely anticipated reversal of Trump-era policies.

The decision, which will take several months to be finalized, reaffirms the Golden State's powerful position as an environmental regulator after the Trump administration had in 2019 sought to remove California's powers to set its own emissions standards.

It also sets the stage for negotiations over how strict federal vehicle standards will be under President Biden.

"I am a firm believer in California's long-standing statutory authority to lead," EPA administration Michael Regan said in a statement.

"The 2019 decision to revoke the state's waiver to enforce its greenhouse gas pollution standards for cars and trucks was legally dubious and an attack on the public's health and wellbeing," he added.

The EPA will be accepting public comment until July 6 as part of the process of reversing the Trump-era rule.

The populous, car-loving state has been waging a battle against smog for decades.

And in recognition of that history, the EPA has long granted a waiver giving the state the authority to set its own standards for vehicle emissions, as long as they're more stringent than the national regulations.

That's an unusual exemption — other states can't set their own policies, although they can choose to adopt California's standards as their own.

Between California and the states that follow suit, about a third of the U.S. new car market is covered by the Golden State's policies, giving California regulators a remarkable amount of sway over the auto industry.

However, when the Trump administration weakened federal clean car standards, it also sought to revoke the waiver allowing California to set a higher bar.

That triggered a legal battle and divided the auto industry, with some carmakers choosing to side with California and voluntarily accept somewhat stricter vehicle emissions standards while the rest backed the Trump administration.

After Biden won the White House, every major automaker eventually dropped their support for the now-doomed Trump position.

The EPA has now started the process of reversing Trump's decision. The Department of Transportation last week also proposed to "wipe clean the regulatory slate," indicating that the National Highway Traffic Safety Administration would no longer seek to block state emissions standards, as it had under Trump.

It's still not clear what federal regulations on vehicle emissions and fuel economy will be under the Biden administration. Some environmental groups and progressive lawmakers are pushing for the reinstatement of the Obama-era standards, with more ambitious targets to follow.

The auto industry, meanwhile, is calling for standards midway between the Obama-era and Trump-era policies.

The EPA says it will propose new fuel economy rules in July.

This content is from Southern California Public Radio. View the original story at SCPR.org.

The Challenge is part of Small Steps to Health and Wealth�, a national Cooperative Extension program developed to motivate Americans to take action to simultaneously improve their health and personal finances. SSHW was built around a framework of 25 research-based behavior change strategies. The Challenge was originally developed in a �paper and pencil� format with printed worksheets and is now available online.

As of January 2, 2010 restaurants, bars and other businesses that serve food and drink in Catawba County became smoke-free. Many health advocates and local residents are pleased that they can now enjoy a healthier dining experience. The ban is a result of a new law that prohibits smoking in all restaurants and bars across North Carolina.

Residents and businesses affected by severe storms and tornado on Oct. 26 in Catawba County can apply for low-interest disaster loans from the U.S. Small Business Administration, SBA Administrator Karen G. Mills announced today. Mills made the loans available in response to a letter from North Carolina Gov. Beverly E. Perdue on Nov. 12, requesting a disaster declaration by the SBA. The declaration covers Lincoln County and the adjacent counties of Burke, Catawba, Cleveland, Gaston, Iredell and Mecklenburg in North Carolina.

A Catawba County Department of Social Services program that helped teenagers enrolled in a poverty reduction and teen pregnancy program better understand the myths of government support programs has been named a winner of a 2011 National Association of Counties (NACo) Achievement Award.

You may now access the Catawba County Library System website from your smartphone, thanks to a recent upgrade to the library�s home page. LS2Mobile is accessible with an iPod Touch or iPhone.

Dentists and other volunteers in Catawba County are teaming up with hundreds of their peers across the state and nation for �Give Kids a Smile!� day. This program is held annually to offer educational materials, provide free dental services to local, qualifying children from underserved families, and raise awareness of the epidemic of untreated dental disease.

New State food rules recently put in place are expected to enforce safe food handling and reduce transmission of food-borne illness.