electron Validation of electron-microscopy maps using solution small-angle X-ray scattering By journals.iucr.org Published On :: 2024-06-27 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. Full Article text
electron Microcrystal electron diffraction structure of Toll-like receptor 2 TIR-domain-nucleated MyD88 TIR-domain higher-order assembly By journals.iucr.org Published On :: 2024-09-04 Eukaryotic TIR (Toll/interleukin-1 receptor protein) domains signal via TIR–TIR interactions, either by self-association or by interaction with other TIR domains. In mammals, TIR domains are found in Toll-like receptors (TLRs) and cytoplasmic adaptor proteins involved in pro-inflammatory signaling. Previous work revealed that the MAL TIR domain (MALTIR) nucleates the assembly of MyD88TIR into crystalline arrays in vitro. A microcrystal electron diffraction (MicroED) structure of the MyD88TIR assembly has previously been solved, revealing a two-stranded higher-order assembly of TIR domains. In this work, it is demonstrated that the TIR domain of TLR2, which is reported to signal as a heterodimer with either TLR1 or TLR6, induces the formation of crystalline higher-order assemblies of MyD88TIR in vitro, whereas TLR1TIR and TLR6TIR do not. Using an improved data-collection protocol, the MicroED structure of TLR2TIR-induced MyD88TIR microcrystals was determined at a higher resolution (2.85 Å) and with higher completeness (89%) compared with the previous structure of the MALTIR-induced MyD88TIR assembly. Both assemblies exhibit conformational differences in several areas that are important for signaling (for example the BB loop and CD loop) compared with their monomeric structures. These data suggest that TLR2TIR and MALTIR interact with MyD88 in an analogous manner during signaling, nucleating MyD88TIR assemblies unidirectionally. Full Article text
electron Refining short-range order parameters from the three-dimensional diffuse scattering in single-crystal electron diffraction data By journals.iucr.org Published On :: 2024-01-01 Our study compares short-range order parameters refined from the diffuse scattering in single-crystal X-ray and single-crystal electron diffraction data. Nb0.84CoSb was chosen as a reference material. The correlations between neighbouring vacancies and the displacements of Sb and Co atoms were refined from the diffuse scattering using a Monte Carlo refinement in DISCUS. The difference between the Sb and Co displacements refined from the diffuse scattering and the Sb and Co displacements refined from the Bragg reflections in single-crystal X-ray diffraction data is 0.012 (7) Å for the refinement on diffuse scattering in single-crystal X-ray diffraction data and 0.03 (2) Å for the refinement on the diffuse scattering in single-crystal electron diffraction data. As electron diffraction requires much smaller crystals than X-ray diffraction, this opens up the possibility of refining short-range order parameters in many technologically relevant materials for which no crystals large enough for single-crystal X-ray diffraction are available. Full Article text
electron Persistence of atoms in molecules: there is room beyond electron densities By journals.iucr.org Published On :: 2024-02-20 Evidence that the electronic structure of atoms persists in molecules to a much greater extent than has been usually admitted is presented. This is achieved by resorting to N-electron real-space descriptors instead of one- or at most two-particle projections like the electron or exchange-correlation densities. Here, the 3N-dimensional maxima of the square of the wavefunction, the so-called Born maxima, are used. Since this technique is relatively unknown to the crystallographic community, a case-based approach is taken, revisiting first the Born maxima of atoms in their ground state and then some of their excited states. It is shown how they survive in molecules and that, beyond any doubt, the distribution of electrons around an atom in a molecule can be recognized as that of its isolated, in many cases excited, counterpart, relating this fact with the concept of energetic promotion. Several other cases that exemplify the applicability of the technique to solve chemical bonding conflicts and to introduce predictability in real-space analyses are also examined. Full Article text
electron Structural analysis of nanocrystals by pair distribution function combining electron diffraction with crystal tilting By journals.iucr.org Published On :: 2024-02-16 As an important characterization method, pair distribution function (PDF) has been extensively used in structural analysis of nanomaterials, providing key insights into the degree of crystallinity, atomic structure, local disorder etc. The collection of scattering signals with good statistics is necessary for a reliable structural analysis. However, current conventional electron diffraction experiments using PDF (ePDF) are limited in their ability to acquire continuous diffraction rings for large nanoparticles. Herein, a new method – tilt-ePDF – is proposed to improve the data quality and compatibility of ePDF by a combination of electron diffraction and specimen tilting. In the present work, a tilt-series of electron diffraction patterns was collected from gold nanoparticles with three different sizes and a standard sample polycrystalline aluminium film for ePDF analysis. The results show that tilt-ePDF can not only enhance the continuity of diffraction rings, but can also improve the signal-to-noise ratio in the high scattering angle range. As a result, compared with conventional ePDF data, tilt-ePDF data provide structure parameters with a better accuracy and lower residual factors in the refinement against the crystal structure. This method provides a new way of utilizing ePDF to obtain accurate local structure information from nanoparticles. Full Article text
electron Dynamical refinement with multipolar electron scattering factors By journals.iucr.org Published On :: 2024-03-21 Dynamical refinement is a well established method for refining crystal structures against 3D electron diffraction (ED) data and its benefits have been discussed in the literature [Palatinus, Petříček & Corrêa, (2015). Acta Cryst. A71, 235–244; Palatinus, Corrêa et al. (2015). Acta Cryst. B71, 740–751]. However, until now, dynamical refinements have only been conducted using the independent atom model (IAM). Recent research has shown that a more accurate description can be achieved by applying the transferable aspherical atom model (TAAM), but this has been limited only to kinematical refinements [Gruza et al. (2020). Acta Cryst. A76, 92–109; Jha et al. (2021). J. Appl. Cryst. 54, 1234–1243]. In this study, we combine dynamical refinement with TAAM for the crystal structure of 1-methyluracil, using data from precession ED. Our results show that this approach improves the residual Fourier electrostatic potential and refinement figures of merit. Furthermore, it leads to systematic changes in the atomic displacement parameters of all atoms and the positions of hydrogen atoms. We found that the refinement results are sensitive to the parameters used in the TAAM modelling process. Though our results show that TAAM offers superior performance compared with IAM in all cases, they also show that TAAM parameters obtained by periodic DFT calculations on the refined structure are superior to the TAAM parameters from the UBDB/MATTS database. It appears that multipolar parameters transferred from the database may not be sufficiently accurate to provide a satisfactory description of all details of the electrostatic potential probed by the 3D ED experiment. Full Article text
electron Analysis of COF-300 synthesis: probing degradation processes and 3D electron diffraction structure By journals.iucr.org Published On :: 2024-05-10 Although COF-300 is often used as an example to study the synthesis and structure of (3D) covalent organic frameworks (COFs), knowledge of the underlying synthetic processes is still fragmented. Here, an optimized synthetic procedure based on a combination of linker protection and modulation was applied. Using this approach, the influence of time and temperature on the synthesis of COF-300 was studied. Synthesis times that were too short produced materials with limited crystallinity and porosity, lacking the typical pore flexibility associated with COF-300. On the other hand, synthesis times that were too long could be characterized by loss of crystallinity and pore order by degradation of the tetrakis(4-aminophenyl)methane (TAM) linker used. The presence of the degradation product was confirmed by visual inspection, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). As TAM is by far the most popular linker for the synthesis of 3D COFs, this degradation process might be one of the reasons why the development of 3D COFs is still lagging compared with 2D COFs. However, COF crystals obtained via an optimized procedure could be structurally probed using 3D electron diffraction (3DED). The 3DED analysis resulted in a full structure determination of COF-300 at atomic resolution with satisfying data parameters. Comparison of our 3DED-derived structural model with previously reported single-crystal X-ray diffraction data for this material, as well as parameters derived from the Cambridge Structural Database, demonstrates the high accuracy of the 3DED method for structure determination. This validation might accelerate the exploitation of 3DED as a structure determination technique for COFs and other porous materials. Full Article text
electron A predicted model-aided reconstruction algorithm for X-ray free-electron laser single-particle imaging By journals.iucr.org Published On :: 2024-06-21 Ultra-intense, ultra-fast X-ray free-electron lasers (XFELs) enable the imaging of single protein molecules under ambient temperature and pressure. A crucial aspect of structure reconstruction involves determining the relative orientations of each diffraction pattern and recovering the missing phase information. In this paper, we introduce a predicted model-aided algorithm for orientation determination and phase retrieval, which has been tested on various simulated datasets and has shown significant improvements in the success rate, accuracy and efficiency of XFEL data reconstruction. Full Article text
electron Structure of Aquifex aeolicus lumazine synthase by cryo-electron microscopy to 1.42 Å resolution By journals.iucr.org Published On :: 2024-07-04 Single-particle cryo-electron microscopy (cryo-EM) has become an essential structural determination technique with recent hardware developments making it possible to reach atomic resolution, at which individual atoms, including hydrogen atoms, can be resolved. In this study, we used the enzyme involved in the penultimate step of riboflavin biosynthesis as a test specimen to benchmark a recently installed microscope and determine if other protein complexes could reach a resolution of 1.5 Å or better, which so far has only been achieved for the iron carrier ferritin. Using state-of-the-art microscope and detector hardware as well as the latest software techniques to overcome microscope and sample limitations, a 1.42 Å map of Aquifex aeolicus lumazine synthase (AaLS) was obtained from a 48 h microscope session. In addition to water molecules and ligands involved in the function of AaLS, we can observe positive density for ∼50% of the hydrogen atoms. A small improvement in the resolution was achieved by Ewald sphere correction which was expected to limit the resolution to ∼1.5 Å for a molecule of this diameter. Our study confirms that other protein complexes can be solved to near-atomic resolution. Future improvements in specimen preparation and protein complex stabilization may allow more flexible macromolecules to reach this level of resolution and should become a priority of study in the field. Full Article text
electron On the structure refinement of metal complexes against 3D electron diffraction data using multipolar scattering factors By journals.iucr.org Published On :: 2024-08-15 This study examines various methods for modelling the electron density and, thus, the electrostatic potential of an organometallic complex for use in crystal structure refinement against 3D electron diffraction (ED) data. It focuses on modelling the scattering factors of iron(III), considering the electron density distribution specific for coordination with organic linkers. We refined the structural model of the metal–organic complex, iron(III) acetylacetonate (FeAcAc), using both the independent atom model (IAM) and the transferable aspherical atom model (TAAM). TAAM refinement initially employed multipolar parameters from the MATTS databank for acetylacetonate, while iron was modelled with a spherical and neutral approach (TAAM ligand). Later, custom-made TAAM scattering factors for Fe—O coordination were derived from DFT calculations [TAAM-ligand-Fe(III)]. Our findings show that, in this compound, the TAAM scattering factor corresponding to Fe3+ has a lower scattering amplitude than the Fe3+ charged scattering factor described by IAM. When using scattering factors corresponding to the oxidation state of iron, IAM inaccurately represents electrostatic potential maps and overestimates the scattering potential of the iron. In addition, TAAM significantly improved the fitting of the model to the data, shown by improved R1 values, goodness-of-fit (GooF) and reduced noise in the Fourier difference map (based on the residual distribution analysis). For 3D ED, R1 values improved from 19.36% (IAM) to 17.44% (TAAM-ligand) and 17.49% (TAAM-ligand-Fe3+), and for single-crystal X-ray diffraction (SCXRD) from 3.82 to 2.03% and 1.98%, respectively. For 3D ED, the most significant R1 reductions occurred in the low-resolution region (8.65–2.00 Å), dropping from 20.19% (IAM) to 14.67% and 14.89% for TAAM-ligand and TAAM-ligand-Fe(III), respectively, with less improvement in high-resolution ranges (2.00–0.85 Å). This indicates that the major enhancements are due to better scattering modelling in low-resolution zones. Furthermore, when using TAAM instead of IAM, there was a noticeable improvement in the shape of the thermal ellipsoids, which more closely resembled those of an SCXRD-refined model. This study demonstrates the applicability of more sophisticated scattering factors to improve the refinement of metal–organic complexes against 3D ED data, suggesting the need for more accurate modelling methods and highlighting the potential of TAAM in examining the charge distribution of large molecular structures using 3D ED. Full Article text
electron Hirshfeld atom refinement and dynamical refinement of hexagonal ice structure from electron diffraction data By journals.iucr.org Published On :: 2024-07-30 Reaching beyond the commonly used spherical atomic electron density model allows one to greatly improve the accuracy of hydrogen atom structural parameters derived from X-ray data. However, the effects of atomic asphericity are less explored for electron diffraction data. In this work, Hirshfeld atom refinement (HAR), a method that uses an accurate description of electron density by quantum mechanical calculation for a system of interest, was applied for the first time to the kinematical refinement of electron diffraction data. This approach was applied here to derive the structure of ordinary hexagonal ice (Ih). The effect of introducing HAR is much less noticeable than in the case of X-ray refinement and it is largely overshadowed by dynamical scattering effects. It led to only a slight change in the O—H bond lengths (shortening by 0.01 Å) compared with the independent atom model (IAM). The average absolute differences in O—H bond lengths between the kinematical refinements and the reference neutron structure were much larger: 0.044 for IAM and 0.046 Å for HAR. The refinement results changed considerably when dynamical scattering effects were modelled – with extinction correction or with dynamical refinement. The latter led to an improvement of the O—H bond length accuracy to 0.021 Å on average (with IAM refinement). Though there is a potential for deriving more accurate structures using HAR for electron diffraction, modelling of dynamical scattering effects seems to be a necessary step to achieve this. However, at present there is no software to support both HAR and dynamical refinement. Full Article text
electron A predicted model-aided one-step classification–multireconstruction algorithm for X-ray free-electron laser single-particle imaging By journals.iucr.org Published On :: 2024-08-28 Ultrafast, high-intensity X-ray free-electron lasers can perform diffraction imaging of single protein molecules. Various algorithms have been developed to determine the orientation of each single-particle diffraction pattern and reconstruct the 3D diffraction intensity. Most of these algorithms rely on the premise that all diffraction patterns originate from identical protein molecules. However, in actual experiments, diffraction patterns from multiple different molecules may be collected simultaneously. Here, we propose a predicted model-aided one-step classification–multireconstruction algorithm that can handle mixed diffraction patterns from various molecules. The algorithm uses predicted structures of different protein molecules as templates to classify diffraction patterns based on correlation coefficients and determines orientations using a correlation maximization method. Tests on simulated data demonstrated high accuracy and efficiency in classification and reconstruction. Full Article text
electron From formulation to structure: 3D electron diffraction for the structure solution of a new indomethacin polymorph from an amorphous solid dispersion By journals.iucr.org Published On :: 2024-08-28 3D electron diffraction (3DED) is increasingly employed to determine molecular and crystal structures from micro-crystals. Indomethacin is a well known, marketed, small-molecule non-steroidal anti-inflammatory drug with eight known polymorphic forms, of which four structures have been elucidated to date. Using 3DED, we determined the structure of a new ninth polymorph, σ, found within an amorphous solid dispersion, a product formulation sometimes used for active pharmaceutical ingredients with poor aqueous solubility. Subsequently, we found that σ indomethacin can be produced from direct solvent evaporation using dichloromethane. These results demonstrate the relevance of 3DED within drug development to directly probe product formulations. Full Article text
electron Roodmus: a toolkit for benchmarking heterogeneous electron cryo-microscopy reconstructions By journals.iucr.org Published On :: 2024-10-15 Conformational heterogeneity of biological macromolecules is a challenge in single-particle averaging (SPA). Current standard practice is to employ classification and filtering methods that may allow a discrete number of conformational states to be reconstructed. However, the conformation space accessible to these molecules is continuous and, therefore, explored incompletely by a small number of discrete classes. Recently developed heterogeneous reconstruction algorithms (HRAs) to analyse continuous heterogeneity rely on machine-learning methods that employ low-dimensional latent space representations. The non-linear nature of many of these methods poses a challenge to their validation and interpretation and to identifying functionally relevant conformational trajectories. These methods would benefit from in-depth benchmarking using high-quality synthetic data and concomitant ground truth information. We present a framework for the simulation and subsequent analysis with respect to the ground truth of cryo-EM micrographs containing particles whose conformational heterogeneity is sourced from molecular dynamics simulations. These synthetic data can be processed as if they were experimental data, allowing aspects of standard SPA workflows as well as heterogeneous reconstruction methods to be compared with known ground truth using available utilities. The simulation and analysis of several such datasets are demonstrated and an initial investigation into HRAs is presented. Full Article text
electron Three-dimensional electron diffraction on clinkers: the belite α'H incommensurate modulated structure By journals.iucr.org Published On :: 2024-03-06 Traditional X-ray methods are extensively applied to commercial cement samples in order to determine their physical and chemical properties. Powder patterns are routinely used to quantify the composition of these phase mixtures, but structure determination becomes difficult because of reflection overlapping caused by the high number of different crystal structures. The fast-growing 3D electron diffraction technique and its related automated acquisition protocols arise as a potentially very interesting tool for the cement industry, since they enable the fast and systematic acquisition of diffraction data from individual particles. In this context, electron diffraction has been used in the investigation of the different crystalline phases present in various commercial clinkers for cement. Automated data collection procedures and subsequent data processing have enabled the structural characterization of the different crystal structures from which the α'H polymorph of Ca2SiO4 (belite) exhibited satellite reflections. Its average crystal structure has been known since 1971 and satellite reflections have been reported previously, yet the modulation was never fully described by means of the superspace formalism. Here, the incommensurately modulated structure is solved and refined using harmonic and crenel functions in the superspace group Pnma(α00)0ss, showing the potential of 3D electron diffraction for systematic crystallographic characterizations of cement. A full description of the different belite polymorphs is provided considering this modulated structure. Full Article text
electron Crystal structures of two new high-pressure oxynitrides with composition SnGe4N4O4, from single-crystal electron diffraction By journals.iucr.org Published On :: 2024-05-08 SnGe4N4O4 was synthesized at high pressure (16 and 20 GPa) and high temperature (1200 and 1500°C) in a large-volume press. Powder X-ray diffraction experiments using synchrotron radiation indicate that the derived samples are mixtures of known and unknown phases. However, the powder X-ray diffraction patterns are not sufficient for structural characterization. Transmission electron microscopy studies reveal crystals of several hundreds of nanometres in size with different chemical composition. Among them, crystals of a previously unknown phase with stoichiometry SnGe4N4O4 were detected and investigated using automated diffraction tomography (ADT), a three-dimensional electron diffraction method. Via ADT, the crystal structure could be determined from single nanocrystals in space group P63mc, exhibiting a nolanite-type structure. This was confirmed by density functional theory calculations and atomic resolution scanning transmission electron microscopy images. In one of the syntheses runs a rhombohedral 6R polytype of SnGe4N4O4 could be found together with the nolanite-type SnGe4N4O4. The structure of this polymorph was solved as well using ADT. Full Article text
electron ProLEED Studio: software for modeling low-energy electron diffraction patterns By journals.iucr.org Published On :: 2024-02-01 Low-energy electron diffraction patterns contain precise information about the structure of the surface studied. However, retrieving the real space lattice periodicity from complex diffraction patterns is challenging, especially when the modeled patterns originate from superlattices with large unit cells composed of several symmetry-equivalent domains without a simple relation to the substrate. This work presents ProLEED Studio software, built to provide simple, intuitive and precise modeling of low-energy electron diffraction patterns. The interactive graphical user interface allows real-time modeling of experimental diffraction patterns, change of depicted diffraction spot intensities, visualization of different diffraction domains, and manipulation of any lattice points or diffraction spots. The visualization of unit cells, lattice vectors, grids and scale bars as well as the possibility of exporting ready-to-publish models in bitmap and vector formats significantly simplifies the modeling process and publishing of results. Full Article text
electron Refinement of X-ray and electron diffraction crystal structures using analytical Fourier transforms of Slater-type atomic wavefunctions in Olex2 By journals.iucr.org Published On :: 2024-02-01 An implementation of Slater-type spherical scattering factors for X-ray and electron diffraction for elements in the range Z = 1–103 is presented within the software Olex2. Both high- and low-angle Fourier behaviour of atomic electron density and electrostatic potential can thus be addressed, in contrast to the limited flexibility of the four Gaussian plus constant descriptions which are currently the most widely used method for calculating atomic scattering factors during refinement. The implementation presented here accommodates the increasing complexity of the electronic structure of heavier elements by using complete atomic wavefunctions without any interpolation between precalculated tables or intermediate fitting functions. Atomic wavefunctions for singly charged ions are implemented and made accessible, and these show drastic changes in electron diffraction scattering factors compared with the neutral atom. A comparison between the two different spherical models of neutral atoms is presented as an example for four different kinds of X-ray and two electron diffraction structures, and comparisons of refinement results using the existing diffraction data are discussed. A systematic but slight improvement in R values and residual densities can be observed when using the new scattering factors, and this is discussed relative to effects on the atomic displacement parameters and atomic positions, which are prominent near the heavier elements in a structure. Full Article text
electron Observations of specimen morphology effects on near-zone-axis convergent-beam electron diffraction patterns By journals.iucr.org Published On :: 2024-03-21 This work presents observations of symmetry breakages in the intensity distributions of near-zone-axis convergent-beam electron diffraction (CBED) patterns that can only be explained by the symmetry of the specimen and not the symmetry of the unit cell describing the atomic structure of the material. The specimen is an aluminium–copper–tin alloy containing voids many tens of nanometres in size within continuous single crystals of the aluminium host matrix. Several CBED patterns where the incident beam enters and exits parallel void facets without the incident beam being perpendicular to these facets are examined. The symmetries in their intensity distributions are explained by the specimen morphology alone using a geometric argument based on the multislice theory. This work shows that it is possible to deduce nanoscale morphological information about the specimen in the direction of the electron beam – the elusive third dimension in transmission electron microscopy – from the inspection of CBED patterns. Full Article text
electron Determination of α lamellae orientation in a β-Ti alloy using electron backscatter diffraction By journals.iucr.org Published On :: 2024-06-27 The spatial orientation of α lamellae in a metastable β-Ti matrix of Timetal LCB (Ti–6.8 Mo–4.5 Fe–1.5 Al in wt%) was examined and the orientation of the hexagonal close-packed α lattice in the α lamella was determined. For this purpose, a combination of methods of small-angle X-ray scattering, scanning electron microscopy and electron backscatter diffraction was used. The habit planes of α laths are close to {111}β, which corresponds to (1320)α in the hexagonal coordinate system of the α phase. The longest α lamella direction lies approximately along one of the 〈110〉β directions which are parallel to the specific habit plane. Taking into account the average lattice parameters of the β and α phases in aged conditions in Timetal LCB, it was possible to index all main axes and faces of an α lath not only in the cubic coordinate system of the parent β phase but also in the hexagonal system of the α phase. Full Article text
electron A simple protocol for determining the zone axis direction from selected-area electron diffraction spot patterns of cubic materials By journals.iucr.org Published On :: 2024-06-18 Using the well known Rn ratio method, a protocol has been elaborated for determining the lattice direction for the 15 most common cubic zone axis spot patterns. The method makes use of the lengths of the three shortest reciprocal-lattice vectors in each pattern and the angles between them. No prior pattern calibration is required for the method to work, as the Rn ratio method is based entirely on geometric relationships. In the first step the pattern is assigned to one of three possible pattern types according to the angles that are measured between the three reciprocal-lattice vectors. The lattice direction [uvw] and possible Bravais type(s) and Laue indices of the corresponding reflections can then be determined by using lookup tables. In addition to determining the lattice direction, this simple geometric analysis allows one to distinguish between the P, I and F Bravais lattices for spot patterns aligned along [013], [112], [114] and [233]. Moreover, the F lattice can always be uniquely identified from the [011] and [123] patterns. Full Article text
electron Low-dose electron microscopy imaging for beam-sensitive metal–organic frameworks By journals.iucr.org Published On :: 2024-09-05 Metal–organic frameworks (MOFs) have garnered significant attention in recent years owing to their exceptional properties. Understanding the intricate relationship between the structure of a material and its properties is crucial for guiding the synthesis and application of these materials. (Scanning) Transmission electron microscopy (S)TEM imaging stands out as a powerful tool for structural characterization at the nanoscale, capable of detailing both periodic and aperiodic local structures. However, the high electron-beam sensitivity of MOFs presents substantial challenges in their structural characterization using (S)TEM. This paper summarizes the latest advancements in low-dose high-resolution (S)TEM imaging technology and its application in MOF material characterization. It covers aspects such as framework structure, defects, and surface and interface analysis, along with the distribution of guest molecules within MOFs. This review also discusses emerging technologies like electron ptychography and outlines several prospective research directions in this field. Full Article text
electron Electronic angle focusing for neutron time-of-flight powder diffractometers By journals.iucr.org Published On :: 2024-10-01 A neutron time-of-flight (TOF) powder diffractometer with a continuous wide-angle array of detectors can be electronically focused to make a single pseudo-constant wavelength diffraction pattern, thus facilitating angle-dependent intensity corrections. The resulting powder diffraction peak profiles are affected by the neutron source emission profile and resemble the function currently used for TOF diffraction. Full Article text
electron Correlative X-ray micro-nanotomography with scanning electron microscopy at the Advanced Light Source By journals.iucr.org Published On :: 2024-10-29 Geological samples are inherently multi-scale. Understanding their bulk physical and chemical properties requires characterization down to the nano-scale. A powerful technique to study the three-dimensional microstructure is X-ray tomography, but it lacks information about the chemistry of samples. To develop a methodology for measuring the multi-scale 3D microstructure of geological samples, correlative X-ray micro- and nanotomography were performed on two rocks followed by scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS) analysis. The study was performed in five steps: (i) micro X-ray tomography was performed on rock sample cores, (ii) samples for nanotomography were prepared using laser milling, (iii) nanotomography was performed on the milled sub-samples, (iv) samples were mounted and polished for SEM analysis and (v) SEM imaging and compositional mapping was performed on micro and nanotomography samples for complimentary information. Correlative study performed on samples of serpentine and basalt revealed multiscale 3D structures involving both solid mineral phases and pore networks. Significant differences in the volume fraction of pores and mineral phases were also observed dependent on the imaging spatial resolution employed. This highlights the necessity for the application of such a multiscale approach for the characterization of complex aggregates such as rocks. Information acquired from the chemical mapping of different phases was also helpful in segmentation of phases that did not exhibit significant contrast in X-ray imaging. Adoption of the protocol used in this study can be broadly applied to 3D imaging studies being performed at the Advanced Light Source and other user facilities. Full Article text
electron Development of hard X-ray photoelectron spectroscopy in liquid cells using optimized microfabricated silicon nitride membranes By journals.iucr.org Published On :: 2024-10-15 We present first hard X-ray photoelectron spectroscopy (HAXPES) results of aqueous salt solutions and dispersions of gold nanoparticles in liquid cells equipped with specially designed microfabricated thin silicon nitride membranes, with thickness in the 15–25 nm range, mounted in a high-vacuum-compatible environment. The experiments have been performed at the HAXPES endstation of the GALAXIES beamline at the SOLEIL synchrotron radiation facility. The low-stress membranes are fabricated from 100 mm silicon wafers using standard lithography techniques. Platinum alignment marks are added to the chips hosting the membranes to facilitate the positioning of the X-ray beam on the membrane by detecting the corresponding photoemission lines. Two types of liquid cells have been used, a static one built on an Omicron-type sample holder with the liquid confined in the cell container, and a circulating liquid cell, in which the liquid can flow in order to mitigate the effects due to beam damage. We demonstrate that the membranes are mechanically robust and able to withstand 1 bar pressure difference between the liquid inside the cell and vacuum, and the intense synchrotron radiation beam during data acquisition. This opens up new opportunities for spectroscopic studies of liquids. Full Article text
electron Electronics component manufacturer selects Conover as national headquarters By www.catawbacountync.gov Published On :: Wed, 12 Sep 2012 14:00:00 EST Smart Electric North America, LLC is opening its North American headquarters in Conover, NC at 1550 Deborah Herman Road SW. SENA plans to build market share by supplying quality components and finished goods to the top tier lighting companies in the US first; then abroad. Full Article News Release FYI Please Choose
electron County offers electronics and paint recycling, year round, at Blackburn Landfill as of July 1. By www.catawbacountync.gov Published On :: Mon, 1 Jul 2013 09:25:00 EST Catawba County offers electronics and paint recycling, year round, at Blackburn Landfill during regular landfill operating hours, as of July 1. Full Article Public Notice News Release FYI
electron A Domestic Electron Ion Collider Would Unlock Scientific Mysteries of Atomic Nuclei, Maintain U.S. Leadership in Accelerator Science, New Report Says By Published On :: Tue, 24 Jul 2018 05:00:00 GMT The science questions that could be answered by an electron ion collider (EIC) – a very large-scale particle accelerator – are significant to advancing our understanding of the atomic nuclei that make up all visible matter in the universe, says a new report by the National Academies of Sciences, Engineering, and Medicine. Full Article
electron EXAIR Dual 316 Stainless Steel Cabinet Cooler Systems with electronic temperature control By www.snackandbakery.com Published On :: Thu, 16 Apr 2020 09:00:00 -0400 EXAIR's new Dual 316 Stainless Steel Cabinet Cooler Systems with ETC (Electronic Temperature Control) keep electrical enclosures cool with 20°F (-7°C) air while maintaining the NEMA 4X rating of the enclosure and removing the heat that could adversely affect the internal components. Full Article
electron LG Electronics USA expands ENERGY STAR-certified line of Inverter Heat Pump Water Heaters By www.pmmag.com Published On :: Mon, 14 Oct 2024 00:00:00 -0400 LG Electronics USA expanded its line of ENERGY STAR-certified Inverter Heat Pump Water Heaters with two new models featuring demand response and a water leakage detection sensor, ensuring a comprehensive domestic water heating solution for residential applications. Full Article
electron Moen introduces electronic cleansing toilet By www.pmmag.com Published On :: Tue, 05 Sep 2023 00:00:00 -0400 The Moen 5-Series eToilet delivers a comfortable and complete clean with its powerful performance all with the push of a button. Full Article
electron Future Electronics Powers the Future with Energy Innovation By www.24-7pressrelease.com Published On :: Thu, 16 Mar 2023 08:00:00 GMT Future Electronics is ready to bring customers into 2023 and beyond with Energy Innovation for the future. Full Article
electron Future Electronics Powers the Future with EV Charging Energy Innovation By www.24-7pressrelease.com Published On :: Mon, 20 Mar 2023 08:00:00 GMT EV charging is a major up and coming industry with incredible innovation opportunities. Future Electronics can guide customers through this industry with their Energy Innovation program. Full Article
electron Future Electronics Powers the Future with Smart Grid & Metering Energy Innovation By www.24-7pressrelease.com Published On :: Wed, 22 Mar 2023 08:00:00 GMT As trends change, smart grids will begin to play a bigger role in the monitoring, control, and distribution of energy. Future Electronics is ready to guide customers through this industry with their Energy Innovation program. Full Article
electron Future Electronics Contributes to Reforestation Efforts in Quebec for Earth Day 2023 By www.24-7pressrelease.com Published On :: Tue, 02 May 2023 08:00:00 GMT Future Electronics is contributing to reforestation efforts in Quebec by matching all employee donations to One Tree Planted. Full Article
electron Future Electronics Montreal Headquarters Goes Green By www.24-7pressrelease.com Published On :: Wed, 03 May 2023 08:00:00 GMT Future Electronics is implementing eco-friendly changes at its Montreal office in an effort to reduce waste and increase sustainability. Full Article
electron Future Electronics to Host Tech Day Event in Montreal By www.24-7pressrelease.com Published On :: Wed, 07 Jun 2023 08:00:00 GMT Future Electronics is hosting Tech Day in Montreal on June 15th, 2023 featuring new technologies, innovations and keynote speakers. Full Article
electron Future Electronics to Host Tech Day Event in Boston By www.24-7pressrelease.com Published On :: Wed, 07 Jun 2023 08:00:00 GMT Future Electronics is hosting Tech Day in Boston on June 13th, 2023 featuring new technologies, demos, and keynote presentations. Full Article
electron Future Electronics Looks Forward to Advanced Engineering University 2023 in Pointe Claire, Quebec By www.24-7pressrelease.com Published On :: Tue, 27 Jun 2023 08:00:00 GMT Future Electronics will host annual Advanced Engineering University in Pointe Claire, Quebec in November 2023. Full Article
electron Future Electronics Hosted one of the most advanced hands-on and interactive learning Event in Boston By www.24-7pressrelease.com Published On :: Mon, 10 Jul 2023 08:00:00 GMT Future Electronics hosted one of the industry's most Advanced hands-on and interactive learning events in Boston for Tech Day 2023. Full Article
electron Future Electronics Hosts Conference for Sales Leaders Across Americas Region By www.24-7pressrelease.com Published On :: Wed, 02 Aug 2023 08:00:00 GMT Future Electronics recently hosted a national sales conference for Sales and Engineering leaders filled with learning, collaborating, and networking opportunities. Full Article
electron Future Electronics Hosts Customers and Suppliers at 2023 Calgary Stampede By www.24-7pressrelease.com Published On :: Wed, 02 Aug 2023 08:00:00 GMT Future Electronics attended the 2023 Calgary Stampede and hosted employees, customers, and suppliers for a VIP experience Full Article
electron Future Electronics Hosts Advanced Engineering University in Singapore By www.24-7pressrelease.com Published On :: Thu, 10 Aug 2023 08:00:00 GMT Future Electronics recently hosted Advanced Engineering University for the first time in Singapore. Full Article
electron Future Electronics Announces Exciting Tech Day Event in Southern California on October 3rd By www.24-7pressrelease.com Published On :: Mon, 25 Sep 2023 08:00:00 GMT Future Electronics will host an exciting Tech Day event in the Southern California region. Full Article
electron Future Electronics wins the 2023 Best Global Distributor Award from Diodes Incorporated By www.24-7pressrelease.com Published On :: Fri, 17 Nov 2023 08:00:00 GMT Future Electronics was presented with the Best Global Distributor award from Diodes Incorporated at their 2023 Global Distribution Conference. Full Article
electron Future Electronics Takes Home Two Awards at Melexis Asia Distribution Summit By www.24-7pressrelease.com Published On :: Mon, 20 Nov 2023 08:00:00 GMT Future Electronics has recently received two awards from the Melexis Asia Distribution Summit. Full Article
electron Diversified Plastics Now Offers Ultra-Precision Micro-Molding of Highly Engineered, Intricate Parts for Medical Devices and Electronics Manufacturing By www.24-7pressrelease.com Published On :: Wed, 07 Jun 2023 08:00:00 GMT DPI's technical representatives and experienced team of engineers work closely with customers, assisting them with design for manufacturing and other value-added services. Full Article
electron Rantle East Electronic Trading Co., Limited Celebrates A Major Gain In Customer Trust As An Electronic Components Supplier By www.24-7pressrelease.com Published On :: Mon, 05 Dec 2022 08:00:00 GMT Rantle East Electronic Trading Co.,Limited, a leading electronic component supplier in China, has announced a milestone in their work. They have now gained the trust of more and more customers who have bought Rantle Electronic components. Full Article
electron CABLETIME Showcases Innovation at Global Exhibitions GITEX 2024 and Global Source Consumer Electronics Autumn Fair By www.24-7pressrelease.com Published On :: Fri, 04 Oct 2024 08:00:00 GMT CABLETIME will showcase at two major events this October: GITEX Global 2024 in Dubai and the Global Source Consumer Electronics Autumn Fair in Hong Kong. Full Article
electron Future Electronics Announces Exciting Tech Day Event in the Pacific Northwest on October 11th By www.24-7pressrelease.com Published On :: Thu, 28 Sep 2023 08:00:00 GMT Future Electronics will host an exciting Tech Day event in the Pacific Northwest region of the USA. Full Article