Shower head leaking? That's definitely annoying but not the end of the world. Shower heads are subject to several problems when it comes to leaks. Learn how to address a dripping shower head.

G-Dragon is rumored to be making a solo comeback this month. He was reportedly shooting a music video last week, with local media outlets speculating his comeback will take place in late...

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Working at BGS  British Geological Survey

A recently discovered β polymorph of 1,3-diacetylpyrene has turned out to be a prominent negative thermal expansion material. Its unique properties can be linked to anharmonic oscillations in the crystal structure. The onset and development of anharmonic behavior have been successfully tracked over a wide temperature range by single-crystal X-ray diffraction experiments. Sufficient diffraction data quality combined with modern quantum crystallography tools allowed a thorough analysis of the elusive anharmonic effects for a moderate-scattering purely organic compound.

The results of the seventh blind test of crystal structure prediction are presented, focusing on structure ranking methods.

The seventh blind test of crystal structure prediction (CSP) methods substantially increased the level of complexity of the target compounds relative to the previous tests organized by the Cambridge Crystallographic Data Centre. In this work, the performance of density-functional methods is assessed using numerical atomic orbitals and the exchange-hole dipole moment dispersion correction (XDM) for the energy-ranking phase of the seventh blind test. Overall, excellent performance was seen for the two rigid molecules (XXVII, XXVIII) and for the organic salt (XXXIII). However, for the agrochemical (XXXI) and pharmaceutical (XXXII) targets, the experimental polymorphs were ranked fairly high in energy amongst the provided candidate structures and inclusion of thermal free-energy corrections from the lattice vibrations was found to be essential for compound XXXI. Based on these results, it is proposed that the importance of vibrational free-energy corrections increases with the number of rotatable bonds.

A seventh blind test of crystal structure prediction has been organized by the Cambridge Crystallographic Data Centre. The results are presented in two parts, with this second part focusing on methods for ranking crystal structures in order of stability. The exercise involved standardized sets of structures seeded from a range of structure generation methods. Participants from 22 groups applied several periodic DFT-D methods, machine learned potentials, force fields derived from empirical data or quantum chemical calculations, and various combinations of the above. In addition, one non-energy-based scoring function was used. Results showed that periodic DFT-D methods overall agreed with experimental data within expected error margins, while one machine learned model, applying system-specific AIMnet potentials, agreed with experiment in many cases demonstrating promise as an efficient alternative to DFT-based methods. For target XXXII, a consensus was reached across periodic DFT methods, with consistently high predicted energies of experimental forms relative to the global minimum (above 4 kJ mol−1 at both low and ambient temperatures) suggesting a more stable polymorph is likely not yet observed. The calculation of free energies at ambient temperatures offered improvement of predictions only in some cases (for targets XXVII and XXXI). Several avenues for future research have been suggested, highlighting the need for greater efficiency considering the vast amounts of resources utilized in many cases.

Hydraulic fracking exposes shale plays to acidic hydraulic fracking fluid (HFF), releasing toxic uranium (U) along with the desired oil and gas. With no existing methods to ensure U remains sequestered in the shale, this study sought to add organic ligands to HFF to explore potential U retention in shale plays. To test this possibility, incubations were set up in which uranyl acetate and one organic bipyridine ligand (either 2,2'-, 2,3'-, 2,4'-, or 4,4'-bipyridine) were added to pristine HFF as the crystallization medium. After several months and complete evaporation of all volatiles, bulk yellow crystalline material was obtained from the incubations, three of which yielded crystals suitable for single-crystal analysis, resulting in two novel structures and a high-quality structure of a previously described compound. The UO2VI acetate complexes bis(acetato-κ2O,O')(2,2'-bipyridine-κ2N,N')dioxidouranium(VI), [U(C2H3O2)2O2(C10H8N2)2] or [2,2'-bipyridine]UVIO2(CH3CO2)2, (I), and bis(acetato-κ2O,O')(2,4'-bipyridine-κN1')dioxidouranium(VI), [U(C2H3O2)2O2(C10H8N2)2] or [2,4'-bipyridine]2UVIO2(CH3CO2)2, (III), contain eight-coordinate UVI in a pseudo-hexagonal bipyramidal coordination geometry and are molecular, packing via weak C—H...O/N interactions, whereas catena-poly[bis(2,3'-bipyridinium) [di-μ-acetato-μ3-hydroxido-μ-hydroxido-di-μ3-oxido-hexaoxidotriuranium(VI)]–2,3'-bipyridine–water (1/1/1)], (C10H9N2)2[U3(C2H3O2)2O8(OH)2]·C10H8N2·H2O or {[2,3'-bipyridinium]2[2,3'-bipyridine][(UVIO2)3(O)2(OH)2(CH3CO2)2·H2O]}n, (II), forms an ionic one-dimensional polymer with seven-coordinate pentagonal bipyramidal UVI centers and hydrogen-bonding interactions within each chain. The formation of these crystals could indicate the potential for bipyridine to bind with U in shale during fracking, which will be explored in a future study via ICP-MS (inductively coupled plasma mass spectrometry) analyses of U concentration in HFF/bipyridine/shale incubations. The variation seen here between the molecular structures may indicate variance in the ability of bipyridine isomers to form complexes with U, which could impact their ability to retain U within shale in the context of fracking.

Here, an open-source Python library for identifying and screening potential stacking fault models in crystalline materials with planar disorder is presented.

Theoretical and experimental structural studies of the title compound were undertaken using X-ray and DFT methods. The inter­actions present in the crystal were analyzed using Hirshfeld surface and MEP surface analysis. Docking studies with a covid-19 main protease (PDB ID: 6LU7) as the target receptor indicate that the synthesized compound may be a potential candidate for pharmaceutical applications.

The title compound is a non-liquid crystal mol­ecule. The mol­ecular crystal is consolidated by C—Br⋯O&z-dbnd;C type contacts running continuously along the [001] direction.

A 6D structure model for face-centred icosahedral quasicrystals consisting of so-called pseudo-Mackay and mini-Bergman-type atomic clusters is proposed based on the structure model of the Al69.1Pd22Cr2.1Fe6.8 3/2 cubic approximant crystal (with space group Pa3, a = 40.5 Å) [Fujita et al. (2013). Acta Cryst. A69, 322–340]. The cluster centres form an icosahedral close sphere packing generated by the occupation domains similar to those in the model proposed by Katz & Gratias [J. Non-Cryst. Solids (1993), 153–154, 187–195], but their size is smaller by a factor τ2 [τ = (1 + (5)1/2)/2]. The clusters cover approximately 99.46% of the atomic structure, and the cluster arrangement exhibits 15 and 19 different local configurations, respectively, for the pseudo-Mackay and mini-Bergman-type clusters. The occupation domains that generate cluster shells are modelled and discussed in terms of structural disorder and local reorganization of the cluster arrangements (phason flip).

In the title compound, C8H9BrN2O2, the C—O—C—C torsion angle between isonicotine and the ethyl group is 180.0 (2)°. Intramolecular N—H...O and C—H...O interactions consolidate the molecular structure. In the crystal, N—H...N interaction form S(5) zigzag chains along [010]. The most significant contributions to the Hirshfeld surface arise from H...H (33.2%), Br...H/H...Br (20.9%), O...H/H...O (11.2%), C...H/H...C (11.1%) and N...H/H...N (10%) contacts. The topology of the three-dimensional energy frameworks was generated using the B3LYP/6–31 G(d,p) model to calculate the total interaction energy. The net interaction energies for the title compound are Eele = 59.2 kJ mol−1, Epol = 15.5 kJ mol−1, Edis = 140.3 kJ mol−1 and Erep = 107.2 kJ mol−1 with a total interaction energy Etot of 128.8 kJ mol−1. The molecular structure was optimized by density functional theory (DFT) at the B3LYP/6–311+G(d,p) level and the theoretical and experimentally obtained parameters were compared. The frontier molecular orbitals HOMO and LUMO were generated, giving an energy gap ΔE of 4.0931 eV. The MEP was generated to identify active sites in the molecule and molecular docking studies carried out with the title compound (ligand) and the covid-19 main protease PDB ID: 6LU7, revealing a moderate binding affinity of −5.4 kcal mol−1.

To fully exploit ultra-short X-ray pulse durations routinely available at X-ray free-electron lasers to follow out-of-equilibrium dynamics, inherent arrival time fluctuations of the X-ray pulse with an external perturbing laser pulse need to be measured. In this work, two methods of arrival time measurement were compared to measure the arrival time jitter of hard X-ray pulses. The methods were photoelectron streaking by a THz field and a transient refractive index change of a semiconductor. The methods were validated by shot-to-shot correction of a pump–probe transient reflectivity measurement. An ultimate shot-to-shot full width at half-maximum error between the devices of 19.2 ± 0.1 fs was measured.

Two-directional beam-tracking (2DBT) is a method for phase-contrast imaging and tomography that uses an intensity modulator to structure the X-ray beam into an array of independent circular beamlets that are resolved by a high-resolution detector. It features isotropic spatial resolution, provides two-dimensional phase sensitivity, and enables the three-dimensional reconstructions of the refractive index decrement, δ, and the attenuation coefficient, μ. In this work, the angular sensitivity and the spatial resolution of 2DBT images in a synchrotron-based implementation is reported. In its best configuration, angular sensitivities of ∼20 nrad and spatial resolution of at least 6.25 µm in phase-contrast images were obtained. Exemplar application to the three-dimensional imaging of soft tissue samples, including a mouse liver and a decellularized porcine dermis, is also demonstrated.

α-d-2'-De­oxy­ribonucleosides are products of the γ-irradiation of DNA under oxygen-free conditions and are constituents of anomeric DNA. They are not found as natural building blocks of canonical DNA. Reports on their conformational properties are limited. Herein, the single-crystal X-ray structure of α-d-2'-de­oxy­adenosine (α-dA), C10H13N5O3, and its conformational parameters were determined. In the crystalline state, α-dA forms two conformers in the asymmetric unit which are connected by hydro­gen bonds. The sugar moiety of each conformer is arranged in a `clamp'-like fashion with respect to the other conformer, forming hydro­gen bonds to its nucleobase and sugar residue. For both conformers, a syn conformation of the nucleobase with respect to the sugar moiety was found. This is contrary to the anti conformation usually preferred by α-nucleosides. The sugar conformation of both conformers is C2'-endo, and the 5'-hydroxyl groups are in a +sc orientation, probably due to the hydro­gen bonds formed by the conformers. The formation of the supra­molecular assembly of α-dA is controlled by hydro­gen bonding and stacking inter­actions, which was verified by a Hirshfeld and curvedness surface analysis. Chains of hydro­gen-bonded nucleobases extend parallel to the b direction and are linked to equivalent chains by hydro­gen bonds involving the sugar moieties to form a sheet. A com­parison of the solid-state structures of the anomeric 2'-de­oxy­adenosines revealed significant differences of their conformational parameters.

The interpretation of cryo-EM maps often includes the docking of known or predicted structures of the components, which is particularly useful when the map resolution is worse than 4 Å. Although it can be effective to search the entire map to find the best placement of a component, the process can be slow when the maps are large. However, frequently there is a well-founded hypothesis about where particular components are located. In such cases, a local search using a map subvolume will be much faster because the search volume is smaller, and more sensitive because optimizing the search volume for the rotation-search step enhances the signal to noise. A Fourier-space likelihood-based local search approach, based on the previously published em_placement software, has been implemented in the new emplace_local program. Tests confirm that the local search approach enhances the speed and sensitivity of the computations. An interactive graphical interface in the ChimeraX molecular-graphics program provides a convenient way to set up and evaluate docking calculations, particularly in defining the part of the map into which the components should be placed.

Crystal polymorphism serves as a strategy to study the conformational flexibility of proteins. However, the relationship between protein crystal packing and protein conformation often remains elusive. In this study, two distinct crystal forms of a green fluorescent protein variant, NowGFP, are compared: a previously identified monoclinic form (space group C2) and a newly discovered ortho­rhombic form (space group P212121). Comparative analysis reveals that both crystal forms exhibit nearly identical linear assemblies of NowGFP molecules interconnected through similar crystal contacts. However, a notable difference lies in the stacking of these assemblies: parallel in the monoclinic form and perpendicular in the orthorhombic form. This distinct mode of stacking leads to different crystal contacts and induces structural alteration in one of the two molecules within the asymmetric unit of the orthorhombic crystal form. This new conformational state captured by orthorhombic crystal packing exhibits two unique features: a conformational shift of the β-barrel scaffold and a restriction of pH-dependent shifts of the key residue Lys61, which is crucial for the pH-dependent spectral shift of this protein. These findings demonstrate a clear connection between crystal packing and alternative conformational states of proteins, providing insights into how structural variations influence the function of fluorescent proteins.

Speckle-tracking X-ray imaging is an attractive candidate for dynamic X-ray imaging owing to its flexible setup and simultaneous yields of phase, transmission and scattering images. However, traditional speckle-tracking imaging methods suffer from phase distortion at locations with abrupt changes in density, which is always the case for real samples, limiting the applications of the speckle-tracking X-ray imaging method. In this paper, we report a deep-learning based method which can achieve dynamic X-ray speckle-tracking imaging with high-accuracy phase retrieval. The calibration results of a phantom show that the profile of the retrieved phase is highly consistent with the theoretical one. Experiments of polyurethane foaming demonstrated that the proposed method revealed the evolution of the complicated microstructure of the bubbles accurately. The proposed method is a promising solution for dynamic X-ray imaging with high-accuracy phase retrieval, and has extensive applications in metrology and quantitative analysis of dynamics in material science, physics, chemistry and biomedicine.

Categorization underlies understanding. Conceptualizing solid-state structures of organic molecules with `archetype crystal structures' bridges established categories of disorder, polymorphism and solid solutions and is herein extended to special position and high-Z' structures. The concept was developed in the context of disorder modelling [Dittrich, B. (2021). IUCrJ, 8, 305–318] and relies on adding quantum chemical energy differences between disorder components to other criteria as an explanation as to why disorder – and disappearing disorder – occurs in an average structure. Part of the concept is that disorder, as probed by diffraction, affects entire molecules, rather than just the parts of a molecule with differing conformations, and the finding that an R·T energy difference between disorder archetypes is usually not exceeded. An illustrative example combining disorder and special positions is the crystal structure of oestradiol hemihydrate analysed here, where its space-group/subgroup relationship is required to explain its disorder of hydrogen-bonded hydrogen atoms. In addition, we show how high-Z' structures can also be analysed energetically and understood via archetypes: high-Z' structures occur when an energy gain from combining different rather than overall alike conformations in a crystal significantly exceeds R·T, and this finding is discussed in the context of earlier explanations in the literature. Twinning is not related to archetype structures since it involves macroscopic domains of the same crystal structure. Archetype crystal structures are distinguished from crystal structure prediction trial structures in that an experimental reference structure is required for them. Categorization into archetype structures also has practical relevance, leading to a new practice of disorder modelling in experimental least-squares refinement alluded to in the above-mentioned publication.

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.

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.

JUAMI, the joint undertaking for an African materials institute, is a project to build collaborations and materials research capabilities between PhD researchers in Africa, the United States, and the world. Focusing on research-active universities in the East African countries of Kenya, Ethiopia, Tanzania and Uganda, the effort has run a series of schools focused on materials for sustainable energy and materials for sustainable development. These bring together early-career researchers from Africa, the US, and beyond, for two weeks in a close-knit environment. The program includes lectures on cutting-edge research from internationally renowned speakers, highly interactive tutorial lectures on the science behind the research, also from internationally known researchers, and hands-on practicals and team-building exercises that culminate in group proposals from self-formed student teams. The schools have benefited more than 300 early-career students and led to proposals that have received funding and have led to research collaborations and educational non-profits. JUAMI continues and has an ongoing community of alumni who share resources and expertise, and is open to like-minded people who want to join and develop contacts and collaborations internationally.

In the title compound, C33H29ClN2O2, the two piperidine rings of the di­aza­bicyclo moiety adopt distorted-chair conformations. Inter­molecular C—H⋯π inter­actions are mainly responsible for the crystal packing. The inter­molecular inter­actions were qu­anti­fied and analysed using Hirshfeld surface analysis, revealing that H⋯H inter­actions contribute most to the crystal packing (52.3%). The mol­ecular structure was further optimized by density functional theory (DFT) at the B3LYP/6–31 G(d,p) level and is compared with the experimentally determined mol­ecular structure in the solid state.

The two mol­ecules in the asymmetric unit of the title compound, C23H24N2O2S, have a structural overlap with an r.m.s. deviation of 0.82 Å. The piperidine rings adopt a distorted boat conformation. Intra- and inter­molecular C—H⋯O hydrogen bonds are responsible for the cohesion of the crystal packing. The inter­molecular inter­actions were qu­anti­fied and analysed using Hirshfeld surface analysis. The mol­ecular structure optimized by density functional theory (DFT) at the B3LYP/6–311++G(d,p)level is compared with the experimentally determined mol­ecular structure in the solid state.

This work describes the X-ray structure of orange–red crystals of 2-meth­oxy-5-nitro­aniline, C7H8N2O3. The compound displays concentration-dependent UV-Vis spectra, which is attributed to dipole-induced aggregation, and light absorption arising from an inter­molecular charge-transfer process that decreases in energy as the degree of aggregation increases. The crystals display π-stacking where the dipole moments align anti­parallel. Stacked mol­ecules inter­act with the next stack via hydrogen bonds, which is a state of maximum aggregation. Light absorption by charge transfer can be compared to colored inorganic semiconductors such as orange–red CdS, with a band gap of 2.0–2.5 eV.

In the title compound, C25H17NO3, the torsion angle associated with the phenyl benzoate group is −173.7 (2)° and that for the benz­yloxy group is −174.8 (2)° establishing an anti-type conformation. The dihedral angles between the ten-membered cyanona­phthalene ring and the aromatic ring of the phenyl benzoate and the benz­yloxy fragments are 40.70 (10) and 87.51 (11)°, respectively, whereas the dihedral angle between the aromatic phenyl benzoate and the benz­yloxy fragments is 72.30 (13)°. In the crystal, the mol­ecules are linked by weak C—H⋯O inter­actions forming S(4) chains propagating parallel to [010]. The packing is consolidated by three C—H⋯π inter­actions and two π–π stacking inter­actions between the aromatic rings of naphthalene and phenyl benzoate with centroid-to-centroid distances of 3.9698 (15) and 3.8568 (15) Å, respectively. Inter­molecular inter­actions were qu­anti­fied using Hirshfeld surface analysis. The mol­ecular structure was further optimized by density functional theory (DFT) at the B3LYP/6–311+ G(d,p) level, revealing that the energy gap between HOMO and LUMO is 3.17 eV. Mol­ecular docking studies were carried out for the title compound as a ligand and SARS-Covid-2(PDB ID:7QF0) protein as a receptor giving a binding affinity of −9.5 kcal mol−1.

This review focuses on low-dose near-field X-ray speckle phase imaging in the differential mode introducing the existing algorithms with their specifications and comparing their performances under various experimental conditions.

A systematic procedure is introduced for modeling charge-neutral non-polar surfaces of ionic minerals containing polyatomic anions. By integrating distance- and charge-based clustering to identify chemical species within the mineral bulk, our pipeline, PolyCleaver, renders a variety of theoretically viable surface terminations. As a demonstrative example, this approach was applied to forsterite (Mg2SiO4), unveiling a rich interface landscape based on interactions with formaldehyde, a relevant multifaceted molecule, and more particularly in prebiotic chemistry. This high-throughput method, going beyond techniques traditionally applied in the modeling of minerals, offers new insights into the potential catalytic properties of diverse surfaces, enabling a broader exploration of synthetic pathways in complex mineral systems.

Polymer-derived ceramics (PDCs) remain at the forefront of research for a variety of applications including ultra-high-temperature ceramics, energy storage and functional coatings. Despite their wide use, questions remain about the complex structural transition from polymer to ceramic and how local structure influences the final microstructure and resulting properties. This is further complicated when nanofillers are introduced to tailor structural and functional properties, as nanoparticle surfaces can interact with the matrix and influence the resulting structure. The inclusion of crystalline nanofiller produces a mixed crystalline–amorphous composite, which poses characterization challenges. With this study, we aim to address these challenges with a local-scale structural study that probes changes in a polysiloxane matrix with incorporated copper nanofiller. Composites were processed at three unique temperatures to capture mixing, pyrolysis and initial crystallization stages for the pre-ceramic polymer. We observed the evolution of the nanofiller with electron microscopy and applied synchrotron X-ray diffraction with differential pair distribution function (d-PDF) analysis to monitor changes in the matrix's local structure and interactions with the nanofiller. The application of the d-PDF to PDC materials is novel and informs future studies to understand interfacial interactions between nanofiller and matrix throughout PDC processing.

From the historical roots of metalworking to the forefront of modern nanotechnology, functional materials have played a pivotal role in transforming societies, and their influence is poised to persist into the future. Encompassing a wide array of solid-state materials, spanning semiconductors to polymers, molecular crystals to nanoparticles, functional materials find application in critical sectors such as electronics, computers, information, communication, bio­technology, aerospace, defense, environment, energy, medicine and consumer products. This feature article delves into diverse instances of functional materials, exploring their structures, their properties and the underlying mechanisms that contribute to their outstanding performance across fields like batteries, photovoltaics, magnetics and heterogeneous catalysts. The field of structural sciences serves as the cornerstone for unraveling the intricate relationship between structure, dynamics and function. Acting as a bridge, it connects the fundamental understanding of materials to their practical applications.

Understanding the structure–property relationship in electrocatalysts under working conditions is crucial for the rational design of novel and improved catalytic materials. This paper presents the Aarhus University reactor for electrochemical studies using X-rays (AUREX) operando electrocatalytic flow cell, designed as an easy-to-use versatile setup with a minimal background contribution and a uniform flow field to limit concentration polarization and handle gas formation. The cell has been employed to measure operando total scattering, diffraction and absorption spectroscopy as well as simultaneous combinations thereof on a commercial silver electrocatalyst for proof of concept. This combination of operando techniques allows for monitoring of the short-, medium- and long-range structure under working conditions, including an applied potential, liquid electrolyte and local reaction environment. The structural transformations of the Ag electrocatalyst are monitored with non-negative matrix factorization, linear combination analysis, the Pearson correlation coefficient matrix, and refinements in both real and reciprocal space. Upon application of an oxidative potential in an Ar-saturated aqueous 0.1 M KHCO3/K2CO3 electrolyte, the face-centered cubic (f.c.c.) Ag gradually transforms first to a trigonal Ag2CO3 phase, followed by the formation of a monoclinic Ag2CO3 phase. A reducing potential immediately reverts the structure to the Ag (f.c.c.) phase. Following the electrochemical-reaction-induced phase transitions is of fundamental interest and necessary for understanding and improving the stability of electrocatalysts, and the operando cell proves a versatile setup for probing this. In addition, it is demonstrated that, when studying electrochemical reactions, a high energy or short exposure time is needed to circumvent beam-induced effects.

Soft X-ray spectroscopy is an important technique for measuring the fundamental properties of materials. However, for measurements of samples in the sub-millimetre range, many experimental setups show limitations. Position drifts on the order of hundreds of micrometres during thermal stabilization of the system can last for hours of expensive beam time. To compensate for drifts, sample tracking and feedback systems must be used. However, in complex sample environments where sample access is very limited, many existing solutions cannot be applied. In this work, we apply a robust computer vision algorithm to automatically track and readjust the sample position in the dozens of micrometres range. Our approach is applied in a complex sample environment, where the sample is in an ultra-high vacuum chamber, surrounded by cooled thermal shields to reach sample temperatures down to 2.5 K and in the center of a superconducting split coil. Our implementation allows sample-position tracking and adjustment in the vertical direction since this is the dimension where drifts occur during sample temperature change in our setup. The approach can be easily extended to 2D. The algorithm enables a factor of ten improvement in the overlap of a series of X-ray absorption spectra in a sample with a vertical size down to 70 µm. This solution can be used in a variety of experimental stations, where optical access is available and sample access by other means is reduced.

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L-R: Three Southern California retro fanatics, John Rabe, Chris Nichols, and Charles Phoenix; Credit: John Rabe/KPCC

Is it possible that the two titans of retro Southern California - Charles Phoenix and Charles Nichols - have never been on Off-Ramp at the same time? But maybe that brings up a larger question. Is it even possible for them to exist in the same place, at the same time, or would their meeting cause a cosmic singularity, an undarnable rending of the time-space continuum?

The answers are, stupidly, yes; and thankfully, yes.

Over the 11 years of Off-Ramp, "God Bless Americana" author Charles Phoenix and Los Angeles Magazine's Chris Nichols have played a large part in bringing interesting and endangered places to our listeners. From Pomona to Chatsworth to Bellflower to Anaheim, both men have made careers of highlighting and preserving things that in their day were seen as expendable, flavor-of-the-month, mass marketed creations. Like programmatic architecture (buildings that look like what they're selling or making, i.e. the Donut Hole in La Puente, the Idle Hour - a giant wine cask - in NoHo).

Yet, with hindsight, we've been able to see them as archetypal and important touchstones of our region.

For their final appearances on the show, they got in the Mercedes and shared their love of getting lost in Southern California.

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

Mastercard has expanded its US...

Saudi Arabia-based fintech infrastructure platform Lean Technologies has raised USD 67.5 million in a Series B funding round to scale its Pay-by-Bank and Open Banking offerings.

; Credit: /Joy Ho for NPR

Perhaps the only respite pandemic closures brought to my family — which includes two kids under age 6 — was freedom from the constant misery of dripping noses, sneezes and coughs. And statistics suggest we weren't the only ones who had fewer colds last year: With daycares and in-person schools closed and widespread use of masks and hand sanitizer in most communities, cases of many seasonal respiratory infections went down, and flu cases dropped off a cliff.

That reprieve might be ending. Social mixing has been starting up again in much of the U.S. and so have cases of garden-variety sniffles. The Centers for Disease Control and Prevention just warned physicians that RSV, a unpleasant respiratory virus, is surging right now in southern states. And it's not just happening in the U.S. — researchers in the U.K. and Hong Kong found that rhinovirus outbreaks spiked there, too, when COVID-19 lockdowns ended.

My family is at the vanguard of this trend. Right after Washington D.C. lifted its mask mandate a few weeks ago, both my kids got runny noses and coughs, and as soon as they tested negative for COVID-19, my pandemic fears were replaced by a familiar dread. I had visions of sleepless, cough-filled nights, dirty tissues everywhere, and — in short order — my own miserable cold.

"If someone in your house is sick, you're not only breathing in their sick air, you're touching those contaminated surfaces. You're having closer contact, you're having longer exposures," says Seema Lakdawala, a researcher at the University of Pittsburgh School of Medicine, who studies how influenza viruses transmit between people. It can start to feel inevitable that the whole family will get sick.

Take heart, my fellow parents-of-adorable-little-germ-machines! Lakdawala says many strategies we all picked up to fight COVID-19 can also stop the spread of many routine respiratory viruses. In fact, they may be even more effective against run-of-the-mill germs, since, unlike the viruses behind most colds, SARS-CoV2 was new to the human immune system.

Those strategies start with everyone keeping their children home from school, camp and playdates when they're sick and keeping up with any and all vaccinations against childhood illnesses. Beyond that, specialists in infectious disease transmission I consulted offer five more tips for keeping my family and yours healthier this summer.

Tip #1: Hang on to those masks

In pre-pandemic times, it might have seemed like a weird move to put on a mask during storytime with your drippy-nosed kid, but Dr. Tina Tan says that's her top tip. She's a professor of pediatrics at the Feinberg School of Medicine at Northwestern University and a pediatric infectious disease physician at Lurie Children's Hospital in Chicago.

When it comes to influenza, a rhinovirus, or any of the other respiratory bugs constantly circulating, "once these viruses touch your mucous membranes, whether it's your eyes, your nose or your mouth, you do have a chance of contracting it," says Tan. Masks help stop infectious particles and virus-filled droplets from getting into your body.

"You don't need a N95," Tan says. A light-weight surgical mask or homemade cloth mask can work as long as it has two or more layers. The mask-wearing also doesn't have to be constant. "If you're going to be face to face with them — they're sitting in your lap, you're reading to them, you're feeding them, etc. — then I would say wear a mask," Tan advises.

Even better, if it's not too uncomfortable for your sick child, have them wear a mask, Lakdawala says. "If your kids are old enough to wear a mask, that would probably be the best strategy, because then you're reducing the amount of virus-laden aerosols in the environment."

How long should you stay masked-up?

For most respiratory viruses, "the infectious period is probably similar to that of COVID," says Dr. Jennifer Shu, a pediatrician in Atlanta and medical editor of the American Academy of Pediatrics' site HealthyChildren.org. It might technically start a few days before symptoms begin and last for up to two weeks, but your sniffly kids are likely most contagious during those first runny-nosed days Shu says. "You could have kids over [age] 2 wear a mask for the first three or four days of symptoms," she suggests.

And if you can't bring yourself to wear a mask or put one on your child inside your own home to fight a cold, don't worry. Lakdawala has a few more ideas.

Tip #2: Air it out, space it out

When Lakdawala's 5- and 8-year-old kids get sick, "I open the windows, I turn on the fans, I get a lot more air circulation going on in the house," she says — that is, weather and allergies permitting, of course.

"A lot of these viruses tend to circulate more during the colder weather, so where you live is going to determine how much you can open your windows," Tan points out. But certainly, she says, "the better the ventilation, the less likely the viruses are going to get transmitted from one person to another."

What about buying HEPA filter air purifiers, or changing the filter in your heating and air conditioning system? "I would not suggest going out to purchase extra HEPA filters just for this purpose," says Dr. Ibukun Kalu, a pediatric infectious disease physician at Duke University. For hospitals that are treating very contagious and serious pathogens like tuberculosis or SARS-CoV2, those upgrades may be important, she says. "But for all of the other routine viruses, it's routine ventilation."

Kalu says you might also want to think strategically about creating some social distance — when it's possible — like strategically having the parent who tends not to get as sick provide the one-on-one care for the sick kid.

Obviously, you can't isolate a sick child in a room by themselves until they recover, but Lakdawala says not getting too close or for too long can help. When her kids are sick, "I do try to just not snuggle them — keep them a little bit at a distance."

Tip #3: Don't try to be a HAZMAT team

There's good news on the house-cleaning front. "Most of these viruses don't live on surfaces for very long periods of time," says Tan.

The research on exactly how long cold-causing rhinoviruses can survive on surfaces — and how likely they are to remain infectious — isn't definitive. As Dr. Donald Goldmann of Boston Children's Hospital poetically put it in The Pediatric Infectious Disease Journal a couple decades ago, "Despite many years of study, from the plains of Salisbury, to the hills of Virginia, to the collegiate environment of Madison, WI, the precise routes rhinovirus takes to inflict the misery of the common cold on a susceptible population remain controversial." That's still true today, doctors say.

There's some evidence that contaminated surfaces are not very important in the spread of colds. In one little study from the 1980s, a dozen healthy men played poker with cards and chips that "were literally gummy" from the secretions of eight other men who had been infected with a rhinovirus as part of the study. Even after 12 hours of poker, none of the healthy volunteers caught colds.

Shu's take home advice? Be methodical in your cleaning of often-touched surfaces (kitchen table, countertops and the like) with soap and water when everybody's healthy, and maybe add bleach wipes or other disinfectant when someone in your household has a cold. But don't panic.

Tan agrees. "Wipe down frequently-touched surfaces multiple times a day," she says. "But you don't have to go crazy and, like, scour everything down with bleach."

You also don't need to do a lot of extra laundry in hopes of eliminating germs on clothes, towels, dishtowels and the like — that can be exhausting and futile. Instead, just try to encourage kids who are sick to use their own towel — and do what you can to give towels a chance to dry out between uses. "Having some common sense and doing laundry every few days — washing your towels every few days and washing your sheets every couple of weeks — is probably good enough," Shu says. "You don't need to go overboard for run-of-the-mill viruses."

Don't fret that there are germs everywhere and you can't touch anything, says Lakdawala. "If I touch something, that -- in itself — is not infecting me," she notes. Instead, it's getting a certain amount of virus on our hands and then touching our own nose, eyes or mouth that can infect us. "If I just go wash my hands, that risk is gone," Lakdawala says.

You can also skip wearing gloves around the house. "People think that they are safe when they're wearing the gloves — and then they touch their face with their gloves [on]" and infect themselves, she says.

Instead, just make it a habit to wash your hands frequently.

Tip #4: Seriously, just wash your hands

"The same handwashing guidelines for COVID also apply for common respiratory illnesses," Shu says. That is: regular soap with warm water, lathered for about 20 seconds.

"The reason why 20 seconds is recommended is because some studies show that washing your hands shorter than that doesn't really get rid of germs." She warns that there hasn't been a whole lot of research on this, and 20 seconds is not a magic number. "But it is thought that anywhere from 15 to 30 seconds is probably good enough to get rid of most of the germs," she says. (Note: No need to drive your family crazy singing the birthday song twice — y'all have options.)

"Wash your hands before you eat, after you eat, after you go to the bathroom ... if you're changing your child's diaper, et cetera.," says Tan. "And if you're going to use hand sanitizer, it has to be at least 60% alcohol."

"Your hands are probably the most important source of transmission outside of someone really coughing or sneezing in your face," Kalu adds.

Tip #5: Don't give up, but do keep perspective

So, what if your beloved child does cough or sneeze in your face? Should you then forget all this stuff and just give in to the inevitable?

Don't give up, says Lakdawala. "Just because you got one large exposure in your mouth and in close range, it doesn't mean that that was sufficient to initiate an infection," she says. Whether you get sick from that germy onslaught is going to depend on a lot of things — the particular virus, whether the sneeze landed in your mouth or nose, whether you've been exposed to some version of that virus before and more.

One tiny positive side effect of the coronavirus pandemic for Lakdawala has been a broader public understanding of "dose-response" in viral transmission. "Just because somebody breathed on you once doesn't necessarily mean that that's what's going to get you infected," she says.

Consider practicing the swiss cheese model of transmission control, Shu says. "Every layer of protection helps — if you find that wearing a face shield is too much, but you do everything else, you're still going to limit your exposure," she says. Just do what works for you and your family.

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

At the tops of many mountains and along numerous roads across the USA are small brass disks called benchmarks.  These survey points are critical for mapping the landscape, determining boundaries, and documenting changes, and there are hundreds of them in Yellowstone National Park!

People come to Catawba County’s web site for many reasons. One is for the information and data that they find there.  The site has always been rich in information about the county and services that are provided. In recent years, as more and more people wanted data in digital format, many datasets were moved to [...]

A fracking site in Kern County, Calif. Fracking — short for hydraulic fracturing — is the process of extracting oil deep underground using a high-pressure water mixture to break up rock.; Credit: Citizens of the Planet/Education Images/Universal Images Group via Getty

California Gov. Gavin Newsom announced plans to ban hydraulic fracturing by 2024 as part of a longer-term aim to end all oil extraction in the state.

The governor has ordered the state's top oil regulator to implement regulation to stop issuing new fracking permits by 2024. He has also directed the state's air resources agency to look at ways to phase out oil extraction completely by 2045.

"The climate crisis is real, and we continue to see the signs every day," Newsom said in a Friday press release. "As we move to swiftly decarbonize our transportation sector and create a healthier future for our children, I've made it clear I don't see a role for fracking in that future and, similarly, believe that California needs to move beyond oil."

The plan aligns with the state's broader goal to reach net-zero carbon dioxide emissions by 2045.

Newsom's order follows a more aggressive plan to ban oil and gas production that died in the state Senate last week.

Following the bill's failure, Rock Zierman, CEO of the California Independent Petroleum Association, told The Desert Sun that it would have killed tens of thousands of jobs "in parts of the state that are struggling in this post-pandemic economy."

"We will continue to oppose bills that only increase our reliance on foreign oil which drives up gas prices, contributes to pollution in our crowded ports, and is produced without California's environmental protections or humanitarian values," he said.

Under Newson's plan, the state's Air Resources Board will assess the economic, environmental and health benefits and effects of ending oil extraction.

In September, Newsom said that fracking accounts for less than 2% of the state's oil production, but that the plan to end the practice is a "symbolic" step. However, some industry groups put that figure at closer to 20%.

The governor has previously said that he lacks the executive authority to ban fracking and has looked to legislators to approve limits.

Now, Newsom is leveraging his authority to take on the state's powerful oil and gas giants during a year in which he will likely face a recall election.

California would be the largest oil-producing state to ban fracking. Environmentalist groups — who argue that fracking drains water levels, harms public health and contributes to global warming — say the 2024 and 2045 deadlines are too late.

"While precedent setting, both timelines are not aggressive enough," California's Sierra Club said in a statement. "They fail to meet the urgency of the climate crisis we face and protect frontline communities facing the brunt of fossil fuel pollution that still need immediate health and safety protections."

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

“The technology services industry, at some level, is recession proof,” Premji said at the company’s 76th annual general meeting on Tuesday. “In good times, clients spend on new initiatives and business transformation and serving customers digitally. They focus on reducing costs when times are not so good,” he said addressing a question on inflation concerns.

Help shape the future of greenways and trails in Catawba County! Catawba County and the Carolina Thread Trail planners ask citizens to help with planning for the trail by taking an online survey.

Do you have any unwanted household products, such as paints, cleansers, solvents, antifreeze, batteries or used motor oils; or electronics like computer equipment, old radios, mobile phones, TVs, VCRs, calculators or copiers? Dispose of them properly, free of charge, on May 7th from 9 a.m. to 3 p.m.

The program of the North Carolina Department of Transportation provides limited funds for low-income persons who need to maintain or insure their car so they can continue working. It is administered by Catawba County Social Services

Used cooking oil will be accepted only at the Blackburn Solidwaste Convenience Center at 3864 Rocky Ford Road, Newton, NC 28658. No business waste accepted. The Blackburn Solidwaste Convenience Center is open Monday through Saturday from 8 a.m. to 6 p.m.

As of October 1, 2012, Catawba County EMS has been named a Permanent Car Seat Checking Station by Buckle Up NC. Car seat checks will be conducted Monday thru Friday, from 9:00 a.m. to 4:00 p.m., by appointment, at the Newton EMS base, located at 1101 South Brady Ave, Newton, NC 28658.

Social Services program honored as one of only 15 programs in U.S. making critical difference in lives of youth in foster care.

; Credit: /Ryan Raphael for NPR

To say Leah Juelke is an award-winning teacher is a bit of an understatement. She was a top 10 finalist for the Global Teacher Prize in 2020; she was North Dakota's Teacher of the Year in 2018; and she was awarded an NEA Foundation award for teaching excellence in 2019.

But Juelke, who teaches high school English learners in Fargo, N.D., says nothing prepared her for teaching during the pandemic.

"The level of stress is exponentially higher. It's like nothing I've experienced before."

It's a sentiment NPR heard from teachers across the country. After a year of uncertainty, long hours and juggling personal and work responsibilities, many told NPR they had reached a breaking point.

Heidi Crumrine, a high school English teacher in Concord, N.H., says this has been the most challenging year she's ever encountered in her two decades of teaching.

"And I say [that] as someone who started her first day of teaching on 9/11 in the Bronx in New York City."

Teaching is one of the most stressful occupations in the U.S., tied only with nurses, a 2013 Gallup poll found. Jennifer Greif Green, an education professor at Boston University, says the additional stress teachers are reporting during the pandemic is worrying because it doesn't only affect educators — it also affects students.

"The mental health and well-being of teachers can have a really important impact on the mental health and well-being of the children who they're spending most of their days with," Green explains. "Having teachers feel safe and supported in their school environments is essential to students learning and being successful."

Lisa Sanetti, a professor of educational psychology at the University of Connecticut, says, "Chronically stressed teachers are just less effective in the classroom."

All that stress can also lead to burnout, which leads to teachers leaving the profession, Sanetti says. "And we have a huge teacher turnover problem in our country."

Districts are trying to help — with yoga classes, counseling sessions and webinars on mental health. Some teachers have organized trivia nights or online happy hours where colleagues can just vent. Teachers told NPR they force themselves to take breaks and go for a bike ride or call a friend. Some have started therapy.

But most of the educators NPR spoke with say they're so exhausted, that even self-care feels like one additional thing to do.

"The reality is, when you're living it, you're just trying to get to the end of the day successfully and try again tomorrow," Crumrine says.

"It feels like we're building the plane while we're flying it"

In March 2020, when schools moved online, teachers across the U.S. had to completely reimagine their approach to education, often with no training or time to prepare. For many, it was a rough transition.

Teachers told NPR they've spent the past year experimenting with different methods of online and hybrid teaching, while also providing tech support for their students and families. Many say they routinely work 12-hour days and on weekends, yet struggle to form relationships with children virtually. Answering emails can take two hours a day.

Rashon Briggs, who teaches high school special education in Los Angeles, spent a lot of time worrying about his students during remote learning (his district only recently started offering in-person options). "One of the biggest challenges is knowing that the kids were not getting the same level of service that they were getting in person," he says.

Teachers in districts that opened earlier for in-person learning say they have additional responsibilities now, such as sanitizing desks between classes, making sure children follow school safety protocols and keeping track of students who have had to quarantine.

"I have a calendar and it says who's quarantined, who is cleared to return on what day, who was absent," explains Rosamund Looney, who teaches first grade in Jefferson Parish, La. "Then I follow up with those families to see: 'Are you OK?' So there's just so much space taken up by that monitoring."

Looney also worries about her students' learning. Everyone in her district has to wear masks in class, which she says she completely agrees with. But those masks mean she can't see her first graders' mouths as they learn phonics.

"You are watching your teacher sound out words and then figuring out how to do that. And it's really hard for me to gauge what they are and aren't able to say." She says she's especially concerned about students who are more at risk of falling behind academically, like English learners.

In New Hampshire, Crumrine says quarantines and positive cases among school staff have led to a constant shifting between fully online and hybrid classes. The fluctuations have been exhausting for her. "We started the year remote. Then we went back to school in October, then we were remote again in November, December. We went back to hybrid [in early February]," she says. New Hampshire's governor has now ordered all schools reopen for full-time, in-person classes by this week.

"It feels like we're building the plane while we're flying it and the destination keeps changing on us," Crumrine says.

Balancing work and home life

In addition to worrying about their students, many teachers are also concerned about their own children. Crumrine, whose husband is also a teacher, has three children and says she feels pulled by competing demands.

"I feel this sense of guilt that I'm not a good enough teacher for my students and I'm not a good mother for my own kids. It just feels like a constant wave of never feeling like I can do what I know I'm good at."

Juelke, in North Dakota, is a single mom with a 9- and 3-year-old. "I'm juggling the children and making sure my daughter is in her class and my 3-year-old is entertained. And that is definitely taking a toll."

Many teachers say they are eating and drinking more, and exercising and sleeping less.

Briggs, in L.A., says his sleeping patterns are completely off. "Being awake all hours of the night, going to bed at 2, 3 a.m., drinking coffee late at night and try to finish work so I can be more prepared the next day."

He's stressed, in part, because there are no clear work-life boundaries anymore. "When you're waking up in the same space that you're on Zoom, that you're grading papers, that you're watching Netflix, those lines are blurred very easily."

Others say they're not as active at home, and they're eating more junk food and putting on weight. The tight schedules means they don't always move between classes, or even remember to drink water.

"There are a lot of dehydrated teachers out there," says Looney.

Many, like Juelke, say they miss having personal time. "That time where I could sit in the car and drive to work and just kind of relax a little, or my prep time at school alone. That's gone now. And so I feel like my mental health has struggled in that way."

She says even though it breaks her heart, she's started looking for another profession.

Leonda Archer, a middle school math teacher in Arlington, Va., says she's usually a very upbeat person, but the pandemic — coupled with the racial turmoil in the country — has taken a toll. She's African American, and says reports of Black men and women being killed by police makes her fear for her husband's safety.

"There were some points of lowness that I hadn't experienced before. There are some days where I feel like it's hard to keep going."

Archer says she has had difficulty sleeping, and doesn't have an appetite. "And right when I get into a groove, another traumatic experience happens."

Briggs says it was hard not being able to process events like George Floyd's death and the Black Lives Matter protests with his colleagues. In the past, those conversations informed what he would say in the classroom to help his own students make sense of the news.

"The teachers were not able to talk to each other about 'How do you talk about this? How do you present that?' " he says. "There was a lack of ability for us to communicate a message about social justice and rights and the wrongs."

Crumrine says she misses the social aspect of being with her students, and other teachers. "We're not eating lunch together. We're not popping into each other's classrooms. We're all in our little silos."

The school reopening divide

Teachers told NPR they feel a growing chasm in their communities: Parents want schools to open, but teachers first want to make sure it's safe. Many feel they are not being included in these conversations, and their concerns aren't being taken seriously.

Crumrine says it's been devastating hearing elected officials and parents criticize teachers, insisting that schools need to open, even though teachers are concerned about their own health. She says some community members acted like online classes meant teachers weren't working at all. In fact, she says, they were working harder than ever. "It just makes it feel so much worse when you read these horrible things that people say about us or these assumptions that they make about what we are or are not doing."

She says many states, including her own, didn't prioritize vaccines for teachers, which to her revealed just "how deep that lack of value of educators is."

Sarahi Monterrey, who teaches English learners in Waukesha, Wisc., says she's felt a "huge divide" in the community. "It almost seems like us against them." She was in a Zoom school board meeting where parents and students were present, and a teacher testified that her husband had COVID-19. "And a parent in the room said, 'Who cares?' And I was blown away. Just blown away."

In Virginia, Archer says, at the beginning of the pandemic, "We were seen as angels. Like, 'Oh my God, I've been home with my child for two months, how do teachers do it?' And now the narrative has totally flip-flopped."

She says she also misses "the vibe of school, the energy, all of that. But I don't want people to be sick."

Archer works 12-hour days, and says people need to remember that teachers are people too. "Our profession is a nurturing one, but we also are humans that need to be poured into. We need to be nurtured, too."

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