stem A versatile sample-delivery system for X-ray photoelectron spectroscopy of in-flight aerosols and free nanoparticles at MAX IV Laboratory By journals.iucr.org Published On :: 2024-08-07 Aerosol science is of utmost importance for both climate and public health research, and in recent years X-ray techniques have proven effective tools for aerosol-particle characterization. To date, such methods have often involved the study of particles collected onto a substrate, but a high photon flux may cause radiation damage to such deposited particles and volatile components can potentially react with the surrounding environment after sampling. These and many other factors make studies on collected aerosol particles challenging. Therefore, a new aerosol sample-delivery system dedicated to X-ray photoelectron spectroscopy studies of aerosol particles and gas molecules in-flight has been developed at the MAX IV Laboratory. The aerosol particles are brought from atmospheric pressure to vacuum in a continuous flow, ensuring that the sample is constantly renewed, thus avoiding radiation damage, and allowing measurements on the true unsupported aerosol. At the same time, available gas molecules can be used for energy calibration and to study gas-particle partitioning. The design features of the aerosol sample-delivery system and important information on the operation procedures are described in detail here. Furthermore, to demonstrate the experimental range of the aerosol sample-delivery system, results from aerosol particles of different shape, size and composition are presented, including inorganic atmospheric aerosols, secondary organic aerosols and engineered nanoparticles. Full Article text
stem Effectiveness of ab initio molecular dynamics in simulating EXAFS spectra from layered systems By journals.iucr.org Published On :: 2024-07-23 The simulation of EXAFS spectra of thin films via ab initio methods is discussed. The procedure for producing the spectra is presented as well as an application to a two-dimensional material (WSe2) where the effectiveness of this method in reproducing the spectrum and the linear dichroic response is shown. A series of further examples in which the method has been employed for the structural determination of materials are given. Full Article text
stem A 1D imaging soft X-ray spectrometer for the small quantum systems instrument at the European XFEL By journals.iucr.org Published On :: 2024-07-30 A 1D imaging soft X-ray spectrometer installed on the small quantum systems (SQS) scientific instrument of the European XFEL is described. It uses movable cylindrical constant-line-spacing gratings in the Rowland configuration for energy dispersion in the vertical plane, and Wolter optics for simultaneous 1D imaging of the source in the horizontal plane. The soft X-ray fluorescence spectro-imaging capability will be exploited in pump–probe measurements and in investigations of propagation effects and other nonlinear phenomena. Full Article text
stem New achievements in orbital angular momentum beam characterization using a Hartmann wavefront sensor and the Kirkpatrick–Baez active optical system KAOS By journals.iucr.org Published On :: 2024-08-16 Advances in physics have been significantly driven by state-of-the-art technology, and in photonics and X-ray science this calls for the ability to manipulate the characteristics of optical beams. Orbital angular momentum (OAM) beams hold substantial promise in various domains such as ultra-high-capacity optical communication, rotating body detection, optical tweezers, laser processing, super-resolution imaging etc. Hence, the advancement of OAM beam-generation technology and the enhancement of its technical proficiency and characterization capabilities are of paramount importance. These endeavours will not only facilitate the use of OAM beams in the aforementioned sectors but also extend the scope of applications in diverse fields related to OAM beams. At the FERMI Free-Electron Laser (Trieste, Italy), OAM beams are generated either by tailoring the emission process on the undulator side or, in most cases, by coupling a spiral zone plate (SZP) in tandem with the refocusing Kirkpatrick–Baez active optic system (KAOS). To provide a robust and reproducible workflow to users, a Hartmann wavefront sensor (WFS) is used for both optics tuning and beam characterization. KAOS is capable of delivering both tightly focused and broad spots, with independent control over vertical and horizontal magnification. This study explores a novel non-conventional `near collimation' operational mode aimed at generating beams with OAM that employs the use of a lithographically manufactured SZP to achieve this goal. The article evaluates the mirror's performance through Hartmann wavefront sensing, offers a discussion of data analysis methodologies, and provides a quantitative analysis of these results with ptychographic reconstructions. Full Article text
stem Vibrational stability improvement of a mirror system using active mass damping By journals.iucr.org Published On :: 2024-08-08 Addressing the demand for high stability of beamline instruments at the SHINE facility, a high stability mirror regulating mechanism has been developed for mirror adjustments. Active mass damping was adopted to attenuate pitch angle vibrations of mirrors caused by structural vibrations. An internal absolute velocity feedback was used to reduce the negative impact of spillover effects and to improve performance. The experiment was conducted on a prototype structure of a mirror regulating mechanism, and results showed that the vibration RMS of the pitch angle was effectively attenuated from 47 nrad to 27 nrad above 1 Hz. Full Article text
stem Development of a flat jet delivery system for soft X-ray spectroscopy at MAX IV By journals.iucr.org Published On :: 2024-08-22 One of the most challenging aspects of X-ray research is the delivery of liquid sample flows into the soft X-ray beam. Currently, cylindrical microjets are the most commonly used sample injection systems for soft X-ray liquid spectroscopy. However, they suffer from several drawbacks, such as complicated geometry due to their curved surface. In this study, we propose a novel 3D-printed nozzle design by introducing microscopic flat sheet jets that provide micrometre-thick liquid sheets with high stability, intending to make this technology more widely available to users. Our research is a collaboration between the EuXFEL and MAX IV research facilities. This collaboration aims to develop and refine a 3D-printed flat sheet nozzle design and a versatile jetting platform that is compatible with multiple endstations and measurement techniques. Our flat sheet jet platform improves the stability of the jet and increases its surface area, enabling more precise scanning and differential measurements in X-ray absorption, scattering, and imaging applications. Here, we demonstrate the performance of this new arrangement for a flat sheet jet setup with X-ray photoelectron spectroscopy, photoelectron angular distribution, and soft X-ray absorption spectroscopy experiments performed at the photoemission endstation of the FlexPES beamline at MAX IV Laboratory in Lund, Sweden. Full Article text
stem Development of an advanced in-line multilayer deposition system at Diamond Light Source By journals.iucr.org Published On :: 2024-08-09 A state-of-the-art multilayer deposition system with a 4200 mm-long linear substrate translator housed within an ultra-high vacuum chamber has been developed. This instrument is engineered to produce single and multilayer coatings, accommodating mirrors up to 2000 mm in length through the utilization of eight rectangular cathodes. To ensure the quality and reliability of the coatings, the system incorporates various diagnostic tools for in situ thickness uniformity and stress measurement. Furthermore, the system features an annealing process capable of heating up to 700°C within the load-lock chamber. The entire operation, including pump down, deposition and venting processes, is automated through user-friendly software. In addition, all essential log data, power of sputtering source, working pressure and motion positions are automatically stored for comprehensive data analysis. Preliminary commissioning results demonstrate excellent lateral film thickness uniformity, achieving 0.26% along the translation direction over 1500 mm in dynamic mode. The multilayer deposition system is poised for use in fabricating periodic, lateral-graded and depth-graded multilayers, specifically catering to the beamlines for diverse scientific applications at Diamond Light Source. Full Article text
stem A distributed software system for integrating data-intensive imaging methods in a hard X-ray nanoprobe beamline at the SSRF By journals.iucr.org Published On :: 2024-08-22 The development of hard X-ray nanoprobe techniques has given rise to a number of experimental methods, like nano-XAS, nano-XRD, nano-XRF, ptychography and tomography. Each method has its own unique data processing algorithms. With the increase in data acquisition rate, the large amount of generated data is now a big challenge to these algorithms. In this work, an intuitive, user-friendly software system is introduced to integrate and manage these algorithms; by taking advantage of the loosely coupled, component-based design approach of the system, the data processing speed of the imaging algorithm is enhanced through optimization of the parallelism efficiency. This study provides meaningful solutions to tackle complexity challenges faced in synchrotron data processing. Full Article text
stem Structural insights into 1,4-bis(neopentyloxy)pillar[5]arene and the pyridine host–guest system By journals.iucr.org Published On :: 2024-11-08 The crystal structure of 1,4-bis(neopentyloxy)pillar[5]arene, C95H140N2O10 (TbuP), featuring two encapsulated pyridine molecules, reveals significant host–guest interactions. Interestingly, the pyridine guests are positioned near the neopentyloxy substituents instead of the electron-rich aromatic core of the pillar[5]arene. This spatial arrangement suggests a preference for the pyridine molecules to engage with the aliphatic regions of the host. Detailed analysis of the structural characteristics of this host–guest system (TbuP·2Py), as well as its packing pattern within the crystal network, is presented and discussed. Full Article text
stem Na[GeF5]·2HF: the first quarternary phase in the H–Na–Ge–F system By journals.iucr.org Published On :: 2024-07-10 The structure of cis- or trans-bridged [GeF5]− anionic chains have been investigated [Mallouk et al. (1984). Inorg. Chem. 23, 3160–3166] showing the first crystal structures of μ-F-bridged pentafluorogermanates. Herein, we report the second crystal structure of trans-pentafluorogermanate anions present in the crystal structure of sodium trans-pentafluorogermanate(IV) bis(hydrogen fluoride), Na[GeF5]·2HF. The crystal structure [orthorhombic Pca21, a = 12.3786 (3), b = 7.2189 (2), c = 11.4969 (3) Å and Z = 8] is built up from infinite chains of trans-linked [GeF6]2− octahedra, extending along the b axis and spanning a network of pentagonal bipyramidal distorted Na-centred polyhedra. These [NaF7] polyhedra are linked in a trans-edge fashion via hydrogen fluoride molecules, in analogy to already known sodium hydrogen fluorides and potassium hydrogen fluorides. Full Article text
stem New insights into the domain of unknown function (DUF) of EccC5, the pivotal ATPase providing the secretion driving force to the ESX-5 secretion system By journals.iucr.org Published On :: 2024-05-28 Type VII secretion (T7S) systems, also referred to as ESAT-6 secretion (ESX) systems, are molecular machines that have gained great attention due to their implications in cell homeostasis and in host–pathogen interactions in mycobacteria. The latter include important human pathogens such as Mycobacterium tuberculosis (Mtb), the etiological cause of human tuberculosis, which constitutes a pandemic accounting for more than one million deaths every year. The ESX-5 system is exclusively found in slow-growing pathogenic mycobacteria, where it mediates the secretion of a large family of virulence factors: the PE and PPE proteins. The secretion driving force is provided by EccC5, a multidomain ATPase that operates using four globular cytosolic domains: an N-terminal domain of unknown function (EccC5DUF) and three FtsK/SpoIIIE ATPase domains. Recent structural and functional studies of ESX-3 and ESX-5 systems have revealed EccCDUF to be an ATPase-like fold domain with potential ATPase activity, the functionality of which is essential for secretion. Here, the crystal structure of the MtbEccC5DUF domain is reported at 2.05 Å resolution, which reveals a nucleotide-free structure with degenerated cis-acting and trans-acting elements involved in ATP binding and hydrolysis. This crystallographic study, together with a biophysical assessment of the interaction of MtbEccC5DUF with ATP/Mg2+, supports the absence of ATPase activity proposed for this domain. It is shown that this degeneration is also present in DUF domains from other ESX and ESX-like systems, which are likely to exhibit poor or null ATPase activity. Moreover, based on an in silico model of the N-terminal region of MtbEccC5DUF, it is hypothesized that MtbEccC5DUF is a degenerated ATPase domain that may have retained the ability to hexamerize. These observations draw attention to DUF domains as structural elements with potential implications in the opening and closure of the membrane pore during the secretion process via their involvement in inter-protomer interactions. Full Article text
stem Managing macromolecular crystallographic data with a laboratory information management system By journals.iucr.org Published On :: 2024-07-10 Protein crystallography is an established method to study the atomic structures of macromolecules and their complexes. A prerequisite for successful structure determination is diffraction-quality crystals, which may require extensive optimization of both the protein and the conditions, and hence projects can stretch over an extended period, with multiple users being involved. The workflow from crystallization and crystal treatment to deposition and publication is well defined, and therefore an electronic laboratory information management system (LIMS) is well suited to management of the data. Completion of the project requires key information on all the steps being available and this information should also be made available according to the FAIR principles. As crystallized samples are typically shipped between facilities, a key feature to be captured in the LIMS is the exchange of metadata between the crystallization facility of the home laboratory and, for example, synchrotron facilities. On completion, structures are deposited in the Protein Data Bank (PDB) and the LIMS can include the PDB code in its database, completing the chain of custody from crystallization to structure deposition and publication. A LIMS designed for macromolecular crystallography, IceBear, is available as a standalone installation and as a hosted service, and the implementation of key features for the capture of metadata in IceBear is discussed as an example. Full Article text
stem STEM SerialED: achieving high-resolution data for ab initio structure determination of beam-sensitive nanocrystalline materials By journals.iucr.org Published On :: 2024-01-01 Serial electron diffraction (SerialED), which applies a snapshot data acquisition strategy for each crystal, was introduced to tackle the problem of radiation damage in the structure determination of beam-sensitive materials by three-dimensional electron diffraction (3DED). The snapshot data acquisition in SerialED can be realized using both transmission and scanning transmission electron microscopes (TEM/STEM). However, the current SerialED workflow based on STEM setups requires special external devices and software, which limits broader adoption. Here, we present a simplified experimental implementation of STEM-based SerialED on Thermo Fisher Scientific STEMs using common proprietary software interfaced through Python scripts to automate data collection. Specifically, we utilize TEM Imaging and Analysis (TIA) scripting and TEM scripting to access the STEM functionalities of the microscope, and DigitalMicrograph scripting to control the camera for snapshot data acquisition. Data analysis adapts the existing workflow using the software CrystFEL, which was developed for serial X-ray crystallography. Our workflow for STEM SerialED can be used on any Gatan or Thermo Fisher Scientific camera. We apply this workflow to collect high-resolution STEM SerialED data from two aluminosilicate zeolites, zeolite Y and ZSM-25. We demonstrate, for the first time, ab initio structure determination through direct methods using STEM SerialED data. Zeolite Y is relatively stable under the electron beam, and STEM SerialED data extend to 0.60 Å. We show that the structural model obtained using STEM SerialED data merged from 358 crystals is nearly identical to that using continuous rotation electron diffraction data from one crystal. This demonstrates that accurate structures can be obtained from STEM SerialED. Zeolite ZSM-25 is very beam-sensitive and has a complex structure. We show that STEM SerialED greatly improves the data resolution of ZSM-25, compared with serial rotation electron diffraction (SerialRED), from 1.50 to 0.90 Å. This allows, for the first time, the use of standard phasing methods, such as direct methods, for the ab initio structure determination of ZSM-25. Full Article text
stem From X-ray crystallographic structure to intrinsic thermodynamics of protein–ligand binding using carbonic anhydrase isozymes as a model system By journals.iucr.org Published On :: 2024-06-10 Carbonic anhydrase (CA) was among the first proteins whose X-ray crystal structure was solved to atomic resolution. CA proteins have essentially the same fold and similar active centers that differ in only several amino acids. Primary sulfonamides are well defined, strong and specific binders of CA. However, minor variations in chemical structure can significantly alter their binding properties. Over 1000 sulfonamides have been designed, synthesized and evaluated to understand the correlations between the structure and thermodynamics of their binding to the human CA isozyme family. Compound binding was determined by several binding assays: fluorescence-based thermal shift assay, stopped-flow enzyme activity inhibition assay, isothermal titration calorimetry and competition assay for enzyme expressed on cancer cell surfaces. All assays have advantages and limitations but are necessary for deeper characterization of these protein–ligand interactions. Here, the concept and importance of intrinsic binding thermodynamics is emphasized and the role of structure–thermodynamics correlations for the novel inhibitors of CA IX is discussed – an isozyme that is overexpressed in solid hypoxic tumors, and thus these inhibitors may serve as anticancer drugs. The abundant structural and thermodynamic data are assembled into the Protein–Ligand Binding Database to understand general protein–ligand recognition principles that could be used in drug discovery. Full Article text
stem Solvatomorphism in a series of copper(II) complexes with the 5-phenylimidazole/perchlorate system as ligands By journals.iucr.org Published On :: 2024-07-30 In the course of an investigation of the supramolecular behaviour of copper(II) complexes with the 5-phenylimidazole/perchlorate ligand system (`blend') remarkable solvatomorphism has been observed. By employing a variety of crystallization solvents (polar protic, polar/non-polar aprotic), a series of 12 crystalline solvatomorphs with the general formula [Cu(ClO4)2(LH)4]·x(solvent) have been obtained [LH = 5-phenylimidazole, x(solvent) = 3.3(H2O) (1), 2(methanol) (2), 2(ethanol) (3), 2(1-propanol) (4), 2(2-propanol) (5), 2(2-butanol) (6), 2(dimethylformamide) (7), 2(acetone) (8), 2(tetrahydrofurane) (9), 2(1,4-dioxane) (10), 2(ethyl acetate) (11) and 1(diethyl ether) (12)]. The structures have been solved using single-crystal X-ray diffraction and the complexes were characterized by thermal analysis and infrared spectroscopy. The solvatomorphs are isostructural (triclinic, P1), with the exception of compound 9 (monoclinic, P21/n). The supramolecular structures and the role of the various solvents is discussed. All potential hydrogen-bond functionalities, both of the [Cu(ClO4)2(LH)4] units and of the solvents, are utilized in the course of the crystallization process. The supramolecular assembly in all structures is directed by strong recurring Nimidazole–H⋯Operchlorate motifs leading to robust scaffolds composed of the [Cu(ClO4)2(LH)4] host complexes. The solvents are located in channels and, with the exception of the disordered waters in 1 and the diethyl ether in 12, participate in hydrogen-bonding formation with the [Cu(ClO4)2(LH)4] complexes, serving as both hydrogen-bond acceptors and donors (for the polar protic solvents in 2–6), or solely as hydrogen-bond acceptors (for the polar/non-polar aprotic solvents in 7–11), linking the complexes and contributing to the stability of the crystalline compounds. Full Article text
stem Development and testing of a dual-frequency, real-time hardware feedback system for the hard X-ray nanoprobe beamline of the SSRF By journals.iucr.org Published On :: we introduce a novel approach for a real-time dual-frequency feedback system, which has been firstly used at the hard X-ray nanoprobe beamline of SSRF. The BiBEST can then efficiently stabilize X-ray beam position and stability in parallel, making use of different optical systems in the beamline. Full Article text
stem Texture measurements on quartz single crystals to validate coordinate systems for neutron time-of-flight texture analysis By journals.iucr.org Published On :: 2023-11-24 In crystallographic texture analysis, ensuring that sample directions are preserved from experiment to the resulting orientation distribution is crucial to obtain physical meaning from diffraction data. This work details a procedure to ensure instrument and sample coordinates are consistent when analyzing diffraction data with a Rietveld refinement using the texture analysis software MAUD. A quartz crystal is measured on the HIPPO diffractometer at Los Alamos National Laboratory for this purpose. The methods described here can be applied to any diffraction instrument measuring orientation distributions in polycrystalline materials. Full Article text
stem Using XAS to monitor radiation damage in real time and post-analysis, and investigation of systematic errors of fluorescence XAS for Cu-bound amyloid-β By journals.iucr.org Published On :: 2024-02-01 X-ray absorption spectroscopy (XAS) is a promising technique for determining structural information from sensitive biological samples, but high-accuracy X-ray absorption fine structure (XAFS) requires corrections of systematic errors in experimental data. Low-temperature XAS and room-temperature X-ray absorption spectro-electrochemical (XAS-EC) measurements of N-truncated amyloid-β samples were collected and corrected for systematic effects such as dead time, detector efficiencies, monochromator glitches, self-absorption, radiation damage and noise at higher wavenumber (k). A new protocol was developed using extended X-ray absorption fine structure (EXAFS) data analysis for monitoring radiation damage in real time and post-analysis. The reliability of the structural determinations and consistency were validated using the XAS measurement experimental uncertainty. The correction of detector pixel efficiencies improved the fitting χ2 by 12%. An improvement of about 2.5% of the structural fitting was obtained after dead-time corrections. Normalization allowed the elimination of 90% of the monochromator glitches. The remaining glitches were manually removed. The dispersion of spectra due to self-absorption was corrected. Standard errors of experimental measurements were propagated from pointwise variance of the spectra after systematic corrections. Calculated uncertainties were used in structural refinements for obtaining precise and reliable values of structural parameters including atomic bond lengths and thermal parameters. This has permitted hypothesis testing. Full Article text
stem RMCProfile7: reverse Monte Carlo for multiphase systems By journals.iucr.org Published On :: 2024-07-31 This work introduces a completely rewritten version of the program RMCProfile (version 7), big-box, reverse Monte Carlo modelling software for analysis of total scattering data. The major new feature of RMCProfile7 is the ability to refine multiple phases simultaneously, which is relevant for many current research areas such as energy materials, catalysis and engineering. Other new features include improved support for molecular potentials and rigid-body refinements, as well as multiple different data sets. An empirical resolution correction and calculation of the pair distribution function as a back-Fourier transform are now also available. RMCProfile7 is freely available for download at https://rmcprofile.ornl.gov/. Full Article text
stem Evolution of elliptical SAXS patterns in aligned systems By journals.iucr.org Published On :: 2024-07-11 Small-angle X-ray and neutron scattering (SAXS and SANS) patterns from certain semicrystalline polymers and liquid crystals contain discrete reflections from ordered assemblies and central diffuse scattering (CDS) from uncorrelated structures. Systems with imperfectly ordered lamellar structures aligned by stretching or by a magnetic field produce four distinct SAXS patterns: two-point `banana', four-point pattern, four-point `eyebrow' and four-point `butterfly'. The peak intensities of the reflections lie not on a layer line, or the arc of a circle, but on an elliptical trajectory. Modeling shows that randomly placed lamellar stacks modified by chain slip and stack rotation or interlamellar shear can create these forms. On deformation, the isotropic CDS becomes an equatorial streak with an oval, diamond or two-bladed propeller shape, which can be analyzed by separation into isotropic and oriented components. The streak has elliptical intensity contours, a natural consequence of the imperfect alignment of the elongated scattering objects. Both equatorial streaks and two- and four-point reflections can be fitted in elliptical coordinates with relatively few parameters. Equatorial streaks can be analyzed to obtain the size and orientation of voids, fibrils or surfaces. Analyses of the lamellar reflection yield lamellar spacing, stack orientation (interlamellar shear) angle α and chain slip angle ϕ, as well as the size distribution of the lamellar stacks. Currently available computational tools allow these microstructural parameters to be rapidly refined. Full Article text
stem On the analysis of two-time correlation functions: equilibrium versus non-equilibrium systems By journals.iucr.org Published On :: 2024-07-04 X-ray photon correlation spectroscopy (XPCS) is a powerful tool for the investigation of dynamics covering a broad range of timescales and length scales. The two-time correlation function (TTC) is commonly used to track non-equilibrium dynamical evolution in XPCS measurements, with subsequent extraction of one-time correlations. While the theoretical foundation for the quantitative analysis of TTCs is primarily established for equilibrium systems, where key parameters such as the diffusion coefficient remain constant, non-equilibrium systems pose a unique challenge. In such systems, different projections (`cuts') of the TTC may lead to divergent results if the underlying fundamental parameters themselves are subject to temporal variations. This article explores widely used approaches for TTC calculations and common methods for extracting relevant information from correlation functions, particularly in the light of comparing dynamics in equilibrium and non-equilibrium systems. Full Article text
stem Flow-Xl: a new facility for the analysis of crystallization in flow systems By journals.iucr.org Published On :: 2024-08-19 Characterization of crystallization processes in situ is of great importance to furthering knowledge of how nucleation and growth processes direct the assembly of organic and inorganic materials in solution and, critically, understanding the influence that these processes have on the final physico-chemical properties of the resulting solid form. With careful specification and design, as demonstrated here, it is now possible to bring combined X-ray diffraction and Raman spectroscopy, coupled to a range of fully integrated segmented and continuous flow platforms, to the laboratory environment for in situ data acquisition for timescales of the order of seconds. The facility used here (Flow-Xl) houses a diffractometer with a micro-focus Cu Kα rotating anode X-ray source and a 2D hybrid photon-counting detector, together with a Raman spectrometer with 532 and 785 nm lasers. An overview of the diffractometer and spectrometer setup is given, and current sample environments for flow crystallization are described. Commissioning experiments highlight the sensitivity of the two instruments for time-resolved in situ data collection of samples in flow. Finally, an example case study to monitor the batch crystallization of sodium sulfate from aqueous solution, by tracking both the solute and solution phase species as a function of time, highlights the applicability of such measurements in determining the kinetics associated with crystallization processes. This work illustrates that the Flow-Xl facility provides high-resolution time-resolved in situ structural phase information through diffraction data together with molecular-scale solution data through spectroscopy, which allows crystallization mechanisms and their associated kinetics to be analysed in a laboratory setting. Full Article text
stem Pushing the limits of accessible length scales via a modified Porod analysis in small-angle neutron scattering on ordered systems By journals.iucr.org Published On :: 2024-08-27 Small-angle neutron scattering is a widely used technique to study large-scale structures in bulk samples. The largest accessible length scale in conventional Bragg scattering is determined by the combination of the longest available neutron wavelength and smallest resolvable scattering angle. A method is presented that circumvents this limitation and is able to extract larger length scales from the low-q power-law scattering using a modification of the well known Porod law connecting the scattered intensity of randomly distributed objects to their specific surface area. It is shown that in the special case of a highly aligned domain structure the specific surface area extracted from the modified Porod law can be used to determine specific length scales of the domain structure. The analysis method is applied to study the micrometre-sized domain structure found in the intermediate mixed state of the superconductor niobium. The analysis approach allows the range of accessible length scales to be extended from 1 µm to up to 40 µm using a conventional small-angle neutron scattering setup. Full Article text
stem Trick or Treat? Astrogeology explores the Solar System’s Halloween spirit. By www.usgs.gov Published On :: Wed, 30 Oct 2024 21:49:34 EDT The Solar System is full of its own tricks and treats, so discover some of our favorites below. Full Article
stem Exploration Co. Seeks Possible Large Copper System in BC By www.streetwisereports.com Published On :: Fri, 01 Nov 2024 00:00:00 PST Vancouver-based minerals explorer Prosper Gold Corp. (TSVX: PGF; OTCQB: PGXFF) is focused on its district-scale Cyprus copper-gold project in north-central British Columbia. One analyst says the results of a recent geophysical survey put the stock in an excellent position. Full Article TSVX: PGF;OTCQB: PGXFF
stem Shallow Discoveries and New Targets at Leviathan Copper System in Idaho By www.streetwisereports.com Published On :: Tue, 05 Nov 2024 00:00:00 PST Hercules Metals Corp. (BADEF:OTCMKTS; BIG:TSXV) has announced advancements in its exploration efforts at the western Idaho Leviathan porphyry copper system. Read more about the significant shallow mineralization discoveries and new target areas that could indicate further resource potential. Full Article
stem Access the Catawba County Library System website from your Smartphone! By www.catawbacountync.gov Published On :: Tue, 2 Aug 2011 11:25:00 EST You may now access the Catawba County Library System website from your smartphone, thanks to a recent upgrade to the library�s home page. LS2Mobile is accessible with an iPod Touch or iPhone. Full Article News Release FYI Please Choose
stem Conover branch of County Library system reopens in new location! By www.catawbacountync.gov Published On :: Tue, 20 Sep 2011 14:55:00 EST The Library re-opened for business in newly renovated space on the top floor of Conover Station. Its new address is 403 Conover Station, SE, in a 1918 structure erected for the Warlong Glove Manufacturing Company. Business hours will remain unchanged: 12 to 8 p.m. Tuesday, 9- 6 p.m. Wednesday through Friday and 9 - 2 on Saturday. Full Article News Release FYI Please Choose
stem Catawba County Library system wins two awards from the North Carolina Public Library Directors� Association. By www.catawbacountync.gov Published On :: Thu, 13 Dec 2012 10:20:00 EST The Catawba County Library System has received two awards from the North Carolina Public Library Directors� Association. Library Director Karen Foss was on hand to accept honors for the new Conover Branch facility and Battle of the Books programming presented at the NCPLDA annual awards banquet December 6 in Winston-Salem. Full Article News Release FYI Please Choose
stem More Effort Needed to Avoid Problems Associated With New Flight Control Systems By Published On :: Tue, 04 Mar 1997 06:00:00 GMT More targeted aircraft testing and simulation should be conducted to uncover design characteristics in new flight control systems that -- in rare circumstances -- may mislead pilots and result in unstable or dangerous flight conditions, says a new report by a National Research Council committee. Full Article
stem Preventing Death and Injury From Medical Errors Requires Dramatic, System-Wide Changes By Published On :: Mon, 29 Nov 1999 06:00:00 GMT Reducing one of the nations leading causes of death and injury – medical errors – will require rigorous changes throughout the health care system, including mandatory reporting requirements. Full Article
stem U.S. Health Care Delivery System Needs Major Overhaul To Improve Quality and Safety By Published On :: Thu, 01 Mar 2001 06:00:00 GMT The nations health care industry has foundered in its ability to provide safe, high-quality care consistently to all Americans, says a new report from the Institute of Medicine of the National Academies. Reorganization and reform are urgently needed to fix what is now a disjointed and inefficient system. Full Article
stem Opening Statement by Paul Tang on Reducing Medical Errors Requires National Computerized Information Systems - Data Standards Are Crucial to Improving Patient Safety By Published On :: Thu, 20 Nov 2003 06:00:00 GMT Welcome to the public release of the latest Institute of Medicine report on the quality of health care in America. Full Article
stem Reducing Medical Errors Requires National Computerized Information Systems - Data Standards Are Crucial to Improving Patient Safety By Published On :: Thu, 20 Nov 2003 06:00:00 GMT To significantly reduce the tens of thousands of deaths and injuries caused by medical errors every year, health care organizations must adopt information technology systems that are capable of collecting and sharing essential health information on patients and their care, says a new report by the Institute of Medicine of the National Academies. Full Article
stem Changes Needed to Improve Operation of U.S. Patent System By Published On :: Mon, 19 Apr 2004 05:00:00 GMT To enhance the vitality and overall operation of the nations patent system, federal officials should take decisive steps to increase the systems flexibility, openness, and reliability, says a new report from the National Academies National Research Council. Full Article
stem Guidelines Released for Embryonic Stem Cell Research By Published On :: Tue, 26 Apr 2005 05:00:00 GMT The National Academies today recommended guidelines for research involving human embryonic stem cells, and urged all institutions conducting such research to establish oversight committees to ensure that the new guidelines will be followed. Full Article
stem Life Elsewhere in Solar System Could Be Different from Life as We Know It By Published On :: Fri, 06 Jul 2007 05:00:00 GMT The search for life elsewhere in the solar system and beyond should include efforts to detect what scientists sometimes refer to as weird life -- that is, life with an alternative biochemistry to that of life on Earth -- says a new report from the National Research Council. Full Article
stem Badly Fragmented Forensic Science System Needs Overhaul - Evidence to Support Reliability of Many Techniques is Lacking By Published On :: Wed, 18 Feb 2009 06:00:00 GMT A congressionally mandated report from the National Research Council finds serious deficiencies in the nations forensic science system and calls for major reforms and new research. Full Article
stem Transformation of Health System Needed to Improve Care and Reduce Costs By Published On :: Thu, 06 Sep 2012 05:00:00 GMT Americas health care system has become too complex and costly to continue business as usual, says a new report from the Institute of Medicine Full Article
stem New Report Calls for Systemwide Reorientation to Account for Health Care and Support of Both Elders and Family Caregivers By Published On :: Tue, 13 Sep 2016 05:00:00 GMT The demand for family caregivers for adults who are 65 or older is increasing significantly, and family caregivers need more recognition, information, and support to fulfill their responsibilities and maintain their own health, financial security, and well-being, says a new report from the National Academies of Sciences, Engineering, and Medicine. Full Article
stem New Report Examines the Impact of Undergraduate Research Experiences for STEM Students By Published On :: Thu, 23 Feb 2017 06:00:00 GMT The call for expanding undergraduates’ access to research experiences in science, technology, engineering, and mathematics (STEM) raises questions about their use and potential to increase students’ interest and persistence in these disciplines. Full Article
stem National Academy of Medicine Releases Publication on How to Improve Nations Health System By Published On :: Tue, 21 Mar 2017 05:00:00 GMT As the nation discusses repealing and replacing the Affordable Care Act, the National Academy of Medicine today released a publication on crosscutting priorities that provides a succinct blueprint to address challenges to Americans’ health and health care that span beyond debates over insurance coverage. Full Article
stem New Report Finds FMCSA’s Safety Measurement System to Be Conceptually Sound, Recommends Implementation Improvements By Published On :: Tue, 27 Jun 2017 05:00:00 GMT While the Federal Motor Carrier Safety Administration’s (FMCSA) Safety Measurement System (SMS) used to identify commercial motor vehicle carriers at high risk for future crashes is conceptually sound, several features of its implementation need improvement, says a new congressionally mandated report from the National Academies of Sciences, Engineering, and Medicine. Full Article
stem Enhancing the Resilience of the Nations Electricity System By Published On :: Thu, 20 Jul 2017 05:00:00 GMT With growing risks to the nation’s electrical grid from natural disasters and as a potential target for malicious attacks, the U.S. Department of Energy (DOE) and the U.S. Department of Homeland Security (DHS) should work closely with utility operators and other stakeholders to improve cyber and physical security and resilience, says a new congressionally mandated report by the National Academies of Sciences, Engineering, and Medicine. Full Article
stem Public Safety During Severe Weather and Other Disasters Could Be Improved With Better Alert Systems and Improved Understanding of Social and Behavioral Factors By Published On :: Wed, 01 Nov 2017 05:00:00 GMT Our ability to observe and predict severe weather events and other disasters has improved markedly over recent decades, yet this progress does not always translate into similar advances in the systems used in such circumstances to protect lives. Full Article
stem Report Offers Framework to Guide Decisions About Spirit Lake and Toutle River System at Mount St. Helens - Inclusive Decision-Making Process Is Needed By Published On :: Fri, 08 Dec 2017 06:00:00 GMT A new report from the National Academies of Sciences, Engineering, and Medicine offers a framework to guide federal, tribal, state and local agencies, community groups, and other interested and affected parties in making decisions about the Spirit Lake and Toutle River system, near Mount St. Helens in southwest Washington state. Full Article
stem Report Offers Guidance on How to Monitor the Quality of STEM Undergraduate Education By Published On :: Wed, 13 Dec 2017 06:00:00 GMT Monitoring the quality and impact of undergraduate science, technology, engineering, and mathematics (STEM) education will require the collection of new national data on changing student demographics, instructors’ use of evidence-based teaching approaches, student transfer patterns, and other dimensions of STEM education, says a new report from the National Academies of Sciences, Engineering, and Medicine. Full Article
stem New Report Calls for Comprehensive Research Campaign to Better Understand, Predict Gulf of Mexico’s Loop Current System By Published On :: Wed, 03 Jan 2018 06:00:00 GMT A new report from the National Academies of Sciences, Engineering, and Medicine calls for an international, multi-institutional comprehensive campaign of research, observation, and analysis activities that would help improve understanding and prediction of the Gulf of Mexico’s Loop Current System (LCS). Full Article
stem Integration of a Wide Range of Safety Systems Is Needed to Develop an In-Time Aviation Safety Management System, New Report Says By Published On :: Thu, 18 Jan 2018 06:00:00 GMT A comprehensive aviation safety system as envisioned by NASA would require integration of a wide range of systems and practices, including building an in-time aviation safety management system (IASMS) that could detect and mitigate high-priority safety issues as they emerge and before they become hazards, says a new report by the National Academies of Sciences, Engineering, and Medicine. Full Article
stem Reforms Needed to Strengthen U.S. Biomedical Research System for Next Generation of Scientists By Published On :: Thu, 12 Apr 2018 05:00:00 GMT A new report from the National Academies of Sciences, Engineering, and Medicine calls for a series of substantial reforms to strengthen the U.S. biomedical research system for the next generation of scientists. Full Article