por The effects of low boron incorporation on the structural and optical properties of BxGa1−xN/SiC epitaxial layers By journals.iucr.org Published On :: The effect of boron in BxGa1−xN/SiC heteroepitaxy was established by X-ray diffraction reciprocal-space maps on symmetric 0002 and asymmetric 11 {overline 2} 4 reflections. The density of screw and edge threading dislocations was quantified in the framework of the mosaic model. Full Article text
por The effects of low boron incorporation on the structural and optical properties of BxGa1−xN/SiC epitaxial layers By journals.iucr.org Published On :: 2024-11-04 BGaN epilayers with boron contents up to 5.6% were grown on SiC substrates by metal–organic chemical vapor deposition. The effects of boron incorporation on the structural and optical properties were studied by high-resolution X-ray diffraction (XRD), atomic force microscopy (AFM), Raman spectroscopy and photoluminescence (PL) spectroscopy. XRD reciprocal-space maps around the symmetric 0002 and asymmetric 11 {overline 2} 4 reflections allowed evaluation of the lattice constants and lattice mismatch with respect to the underlying substrate. XRD rocking curves and AFM measurements indicated the mosaic microstructure of the epilayer. The impact of boron content on crystallite size, tilt and twist is evaluated and the correlation with threading dislocation density is discussed. The deterioration of optical properties with increasing boron content was assessed by Raman and PL spectroscopy. Full Article text
por Optimizing crucible geometry to improve the quality of AlN crystals by the physical vapor transport method By journals.iucr.org Published On :: 2024-10-16 In the conventional crucible structure for AlN crystal growth by physical vapor transport, owing to the long molecular transport path of Al vapor and the disruption of the gas flow by the presence of a deflector, the Al vapor easily forms polycrystals in the growth domain. The result is increased internal stress in the crystals and increased difficulty in growing large-sized crystals. On this basis, with the help of finite element simulations, a novel crucible structure is designed. This crucible not only optimizes the gas transport but also increases the radial gradient of the AlN crystal surface, making the enhanced growth rate in the central region more obvious. The thermal stresses between the deflector and the crystal are also reduced. High-quality AlN crystals with an FWHM of 79 arcsec were successfully grown with this structure, verifying the accuracy of finite element simulation of the growth of AlN crystals. Our work has important guiding significance for the growth of high-quality AlN crystals. Full Article text
por Deep learning to overcome Zernike phase-contrast nanoCT artifacts for automated micro-nano porosity segmentation in bone By journals.iucr.org Published On :: 2024-01-01 Bone material contains a hierarchical network of micro- and nano-cavities and channels, known as the lacuna-canalicular network (LCN), that is thought to play an important role in mechanobiology and turnover. The LCN comprises micrometer-sized lacunae, voids that house osteocytes, and submicrometer-sized canaliculi that connect bone cells. Characterization of this network in three dimensions is crucial for many bone studies. To quantify X-ray Zernike phase-contrast nanotomography data, deep learning is used to isolate and assess porosity in artifact-laden tomographies of zebrafish bones. A technical solution is proposed to overcome the halo and shade-off domains in order to reliably obtain the distribution and morphology of the LCN in the tomographic data. Convolutional neural network (CNN) models are utilized with increasing numbers of images, repeatedly validated by `error loss' and `accuracy' metrics. U-Net and Sensor3D CNN models were trained on data obtained from two different synchrotron Zernike phase-contrast transmission X-ray microscopes, the ANATOMIX beamline at SOLEIL (Paris, France) and the P05 beamline at PETRA III (Hamburg, Germany). The Sensor3D CNN model with a smaller batch size of 32 and a training data size of 70 images showed the best performance (accuracy 0.983 and error loss 0.032). The analysis procedures, validated by comparison with human-identified ground-truth images, correctly identified the voids within the bone matrix. This proposed approach may have further application to classify structures in volumetric images that contain non-linear artifacts that degrade image quality and hinder feature identification. Full Article text
por Teaching about the birth of synchrotron light: the role of Frascati and a missed opportunity By journals.iucr.org Published On :: 2024-05-21 The users of synchrotron light are now tens of thousands throughout the world. Paradoxically, many of them do not know much about the early history of their domain. This is regrettable, since education about the initial developments makes it easier to fully understand synchrotron radiation and effectively use its amazing features. Scarcely known, in particular, is the key role of scientists working in Frascati, Italy. Partly based on his personal experiences, the author reports here relevant aspects of this story, including a pioneering French–Italian experiment that started in the early 1960s, and the Frascati contributions in the 1970s and 1980s to the birth of synchrotron light research. Finally, the unwise strategic decisions that prevented Italy from achieving absolute leadership in this domain – in spite of its unique initial advantages – are analyzed. Full Article text
por Development of a portable and cost-effective femtosecond fibre laser synchronizable with synchrotron X-ray pulses By journals.iucr.org Published On :: 2024-06-20 This study introduces a compact, portable femtosecond fibre laser system designed for synchronization with SPring-8 synchrotron X-ray pulses in a uniform filling mode. Unlike traditional titanium–sapphire mode-locked lasers, which are fixed installations, our system utilizes fibre laser technology to provide a practical alternative for time-resolved spectroscopy, striking a balance between usability, portability and cost-efficiency. Comprehensive evaluations, including pulse characterization, timing jitter and frequency stability tests revealed a centre wavelength of 1600 nm, a pulse energy of 4.5 nJ, a pulse duration of 35 fs with a timing jitter of less than 9 ps, confirming the suitability of the system for time-resolved spectroscopic studies. This development enhances the feasibility of experiments that combine synchrotron X-rays and laser pulses, offering significant scientific contributions by enabling more flexible and diverse research applications. Full Article text
por The effect of transport apertures on relay-imaged, sharp-edged laser profiles in photoinjectors and the impact on electron beam properties By journals.iucr.org Published On :: 2024-06-06 In a photoinjector electron source, the initial transverse electron bunch properties are determined by the spatial properties of the laser beam on the photocathode. Spatial shaping of the laser is commonly achieved by relay imaging an illuminated circular mask onto the photocathode. However, the Gibbs phenomenon shows that recreating the sharp edge and discontinuity of the cut profile at the mask on the cathode is not possible with an optical relay of finite aperture. Furthermore, the practical injection of the laser into the photoinjector results in the beam passing through small or asymmetrically positioned apertures. This work uses wavefront propagation to show how the transport apertures cause ripple structures to appear in the transverse laser profile even when effectively the full laser power is transmitted. The impact of these structures on the propagated electron bunch has also been studied with electron bunches of high and low charge density. With high charge density, the ripples in the initial charge distribution rapidly wash-out through space charge effects. However, for bunches with low charge density, the ripples can persist through the bunch transport. Although statistical properties of the electron bunch in the cases studied are not greatly affected, there is the potential for the distorted electron bunch to negatively impact machine performance. Therefore, these effects should be considered in the design phase of accelerators using photoinjectors. Full Article text
por Characterization of silicon pore optics for the NewAthena X-ray observatory in the PTB laboratory at BESSY II By journals.iucr.org Published On :: 2024-06-24 The New Advanced Telescope for High ENergy Astrophysics (NewAthena) will be the largest space-based X-ray observatory ever built. It will have an effective area above 1.1 m2 at 1 keV, which corresponds to a polished mirror surface of about 300 m2 due to the grazing incidence. As such a mirror area is not achievable with an acceptable mass even with nested shells, silicon pore optics (SPO) technology will be utilized. In the PTB laboratory at BESSY II, two dedicated beamlines are in use for their characterization with monochromatic radiation at 1 keV and a low divergence well below 2 arcsec: the X-ray Pencil Beam Facility (XPBF 1) and the X-ray Parallel Beam Facility (XPBF 2.0), where beam sizes up to 8 mm × 8 mm are available while maintaining low beam divergence. This beamline is used for characterizing mirror stacks and controlling the focusing properties of mirror modules (MMs) – consisting of four mirror stacks – during their assembly at the beamline. A movable CCD based camera system 12 m from the MM registers the direct and the reflected beams. The positioning of the detector is verified by a laser tracker. The energy-dependent reflectance in double reflection through the pores of an MM with an Ir coating was measured at the PTB four-crystal monochromator beamline in the photon energy range 1.75 keV to 10 keV, revealing the effects of the Ir M edges. The measured reflectance properties are in agreement with the design values to achieve the envisaged effective area. Full Article text
por New opportunities for time-resolved imaging using diffraction-limited storage rings By journals.iucr.org Published On :: 2024-07-30 The advent of diffraction-limited storage rings (DLSRs) has boosted the brilliance or coherent flux by one to two orders of magnitude with respect to the previous generation. One consequence of this brilliance enhancement is an increase in the flux density or number of photons per unit of area and time, which opens new possibilities for the spatiotemporal resolution of X-ray imaging techniques. This paper studies the time-resolved microscopy capabilities of such facilities by benchmarking the ForMAX beamline at the MAX IV storage ring. It is demonstrated that this enhanced flux density using a single harmonic of the source allows micrometre-resolution time-resolved imaging at 2000 tomograms per second and 1.1 MHz 2D acquisition rates using the full dynamic range of the detector system. Full Article text
por meso-α,α-5,15-Bis(o-nicotinamidophenyl)-10,20-diphenylporphyrin n-hexane monosolvate By journals.iucr.org Published On :: 2023-12-22 The structure of the title solvated porphyrin, C56H38N8O2·C6H14, is reported. Two porphyrin molecules, one ordered and one disordered n-hexane solvate molecules are present in its asymmetric unit. The porphyrin macrocycle shows a characteristic saddle-shaped distortion, and the maximum deviation from the mean plane for non-hydrogen atoms is 0.48 Å. N—H⋯N, N—H⋯O, and C—H⋯O hydrogen bonds, as well as π–π interactions, are observed in the crystal structure. Full Article text
por Chlorido[5,10,15,20-tetrakis(quinoline-7-carboxamido)porphinato]iron(III) By journals.iucr.org Published On :: 2024-06-04 The title compound, [Fe(C84H52N12O4)Cl], crystallizes in space group C2/c. The central FeIII cation (site symmetry 2) is coordinated in a fivefold manner, with four pyrrole N atoms of the porphyrin core in the basal sites and one Cl atom (site symmetry 2) in the apical position, which completes a slightly distorted square-pyramidal environment. The porphyrin macrocycle shows a characteristic ruffled-shape distortion and the iron atom is displaced out of the porphyrin plane by 0.42 Å with the average Fe—N distance being 2.054 (4) Å; the Fe—Cl bond length is 2.2042 (7) Å. Intermolecular C—H⋯N and C—H⋯O hydrogen bonds occur in the crystal structure. Full Article text
por (2,5-Dimethylimidazole){N,N',N'',N'''-[porphyrin-5,10,15,20-tetrayltetra(2,1-phenylene)]tetrakis(pyridine-3-carboxamide)}manganese(II) chlorobenzene disolvate By journals.iucr.org Published On :: 2024-06-04 In the title compound, [Mn(C68H44N12O4)(C5H8N2)]·2C6H5Cl, the central MnII ion is coordinated by four pyrrole N atoms of the porphyrin core in the basal sites and one N atom of the 2,5-dimethylimidazole ligand in the apical site. Two chlorobenzene solvent molecules are also present in the asymmetric unit. Due to the apical imidazole ligand, the Mn atom is displaced out of the 24-atom porphyrin mean plane by 0.66 Å. The average Mn—Np (p = porphyrin) bond length is 2.143 (8) Å, and the axial Mn—NIm (Im = 2,5-dimethylimidazole) bond length is 2.171 (8) Å. The structure displays intermolecular and intramolecular N—H⋯O, N—H⋯N, C—H⋯O and C—H⋯N hydrogen bonding. The crystal studied was refined as a two-component inversion twin. Full Article text
por meso-5,15-Bis[3-(isopropylidenegalactopyranoxy)phenyl]-10,20-bis(4-methylphenyl)porphyrin By journals.iucr.org Published On :: 2024-10-24 The crystal structure of a glycosylated porphyrin (P_Gal2) system, C70H70N4O12, where two isopropylidene protected galactose moieties are attached to the meso position of a substituted tetraaryl porphyrin is reported. This structure reveals that the parent porphyrin is planar, with the galactose moieties positioned above and below the porphyrin macrocycle. This orientation likely prevents porphyrin–porphyrin H-type aggregation, potentially enhancing its efficiency as a photosensitizer in photodynamic therapy. Notable non-bonding C—H⋯O and C—H⋯π interactions among adjacent P_Gal2 systems are observed in this crystal network. Additionally, the tolyl groups of each porphyrin can engage in π–π interactions with the delocalized π-systems of neighboring porphyrins. Full Article text
por On the importance of crystal structures for organic thin film transistors By journals.iucr.org Published On :: 2024-09-04 Historically, knowledge of the molecular packing within the crystal structures of organic semiconductors has been instrumental in understanding their solid-state electronic properties. Nowadays, crystal structures are thus becoming increasingly important for enabling engineering properties, understanding polymorphism in bulk and in thin films, exploring dynamics and elucidating phase-transition mechanisms. This review article introduces the most salient and recent results of the field. Full Article text
por A small step towards an important goal: fragment screen of the c-di-AMP-synthesizing enzyme CdaA By journals.iucr.org Published On :: 2024-04-29 CdaA is the most widespread diadenylate cyclase in many bacterial species, including several multidrug-resistant human pathogens. The enzymatic product of CdaA, cyclic di-AMP, is a secondary messenger that is essential for the viability of many bacteria. Its absence in humans makes CdaA a very promising and attractive target for the development of new antibiotics. Here, the structural results are presented of a crystallographic fragment screen against CdaA from Listeria monocytogenes, a saprophytic Gram-positive bacterium and an opportunistic food-borne pathogen that can cause listeriosis in humans and animals. Two of the eight fragment molecules reported here were localized in the highly conserved ATP-binding site. These fragments could serve as potential starting points for the development of antibiotics against several CdaA-dependent bacterial species. Full Article text
por Introduction of the Capsules environment to support further growth of the SBGrid structural biology software collection By journals.iucr.org Published On :: 2024-06-04 The expansive scientific software ecosystem, characterized by millions of titles across various platforms and formats, poses significant challenges in maintaining reproducibility and provenance in scientific research. The diversity of independently developed applications, evolving versions and heterogeneous components highlights the need for rigorous methodologies to navigate these complexities. In response to these challenges, the SBGrid team builds, installs and configures over 530 specialized software applications for use in the on-premises and cloud-based computing environments of SBGrid Consortium members. To address the intricacies of supporting this diverse application collection, the team has developed the Capsule Software Execution Environment, generally referred to as Capsules. Capsules rely on a collection of programmatically generated bash scripts that work together to isolate the runtime environment of one application from all other applications, thereby providing a transparent cross-platform solution without requiring specialized tools or elevated account privileges for researchers. Capsules facilitate modular, secure software distribution while maintaining a centralized, conflict-free environment. The SBGrid platform, which combines Capsules with the SBGrid collection of structural biology applications, aligns with FAIR goals by enhancing the findability, accessibility, interoperability and reusability of scientific software, ensuring seamless functionality across diverse computing environments. Its adaptability enables application beyond structural biology into other scientific fields. Full Article text
por RCSB Protein Data Bank: supporting research and education worldwide through explorations of experimentally determined and computationally predicted atomic level 3D biostructures By journals.iucr.org Published On :: 2024-04-10 The Protein Data Bank (PDB) was established as the first open-access digital data resource in biology and medicine in 1971 with seven X-ray crystal structures of proteins. Today, the PDB houses >210 000 experimentally determined, atomic level, 3D structures of proteins and nucleic acids as well as their complexes with one another and small molecules (e.g. approved drugs, enzyme cofactors). These data provide insights into fundamental biology, biomedicine, bioenergy and biotechnology. They proved particularly important for understanding the SARS-CoV-2 global pandemic. The US-funded Research Collaboratory for Structural Bioinformatics Protein Data Bank (RCSB PDB) and other members of the Worldwide Protein Data Bank (wwPDB) partnership jointly manage the PDB archive and support >60 000 `data depositors' (structural biologists) around the world. wwPDB ensures the quality and integrity of the data in the ever-expanding PDB archive and supports global open access without limitations on data usage. The RCSB PDB research-focused web portal at https://www.rcsb.org/ (RCSB.org) supports millions of users worldwide, representing a broad range of expertise and interests. In addition to retrieving 3D structure data, PDB `data consumers' access comparative data and external annotations, such as information about disease-causing point mutations and genetic variations. RCSB.org also provides access to >1 000 000 computed structure models (CSMs) generated using artificial intelligence/machine-learning methods. To avoid doubt, the provenance and reliability of experimentally determined PDB structures and CSMs are identified. Related training materials are available to support users in their RCSB.org explorations. Full Article text
por The importance of definitions in crystallography By journals.iucr.org Published On :: 2024-05-28 This paper was motivated by the articles `Same or different – that is the question' in CrystEngComm (July 2020) and `Change to the definition of a crystal' in the IUCr Newsletter (June 2021). Experimental approaches to crystal comparisons require rigorously defined classifications in crystallography and beyond. Since crystal structures are determined in a rigid form, their strongest equivalence in practice is rigid motion, which is a composition of translations and rotations in 3D space. Conventional representations based on reduced cells and standardizations theoretically distinguish all periodic crystals. However, all cell-based representations are inherently discontinuous under almost any atomic displacement that can arbitrarily scale up a reduced cell. Hence, comparison of millions of known structures in materials databases requires continuous distance metrics. Full Article text
por The evolution of raw data archiving and the growth of its importance in crystallography By journals.iucr.org Published On :: 2024-06-12 The hardware for data archiving has expanded capacities for digital storage enormously in the past decade or more. The IUCr evaluated the costs and benefits of this within an official working group which advised that raw data archiving would allow ground truth reproducibility in published studies. Consultations of the IUCr's Commissions ensued via a newly constituted standing advisory committee, the Committee on Data. At all stages, the IUCr financed workshops to facilitate community discussions and possible methods of raw data archiving implementation. The recent launch of the IUCrData journal's Raw Data Letters is a milestone in the implementation of raw data archiving beyond the currently published studies: it includes diffraction patterns that have not been fully interpreted, if at all. The IUCr 75th Congress in Melbourne included a workshop on raw data reuse, discussing the successes and ongoing challenges of raw data reuse. This article charts the efforts of the IUCr to facilitate discussions and plans relating to raw data archiving and reuse within the various communities of crystallography, diffraction and scattering. Full Article text
por Importance of powder diffraction raw data archival in a curated database for materials science applications By journals.iucr.org Published On :: 2024-08-26 In recent years, there is a significant interest from the crystallographic and materials science communities to have access to raw diffraction data. The effort in archiving raw data for access by the user community is spearheaded by the International Union of Crystallography (IUCr) Committee on Data. In materials science, where powder diffraction is extensively used, the challenge in archiving raw data is different to that from single crystal data, owing to the very nature of the contributions involved. Powder diffraction (X-ray or neutron) data consist of contributions from the material under study as well as instrument specific parameters. Having raw powder diffraction data can be essential in cases of analysing materials with poor crystallinity, disorder, micro structure (size/strain) etc. Here, the initiative and progress made by the International Centre for Diffraction Data (ICDDR) in archiving powder X-ray diffraction raw data in the Powder Diffraction FileTM (PDFR) database is outlined. The upcoming 2025 release of the PDF-5+ database will have more than 20 800 raw powder diffraction patterns that are available for reference. Full Article text
por Trifluoromethanesulfonate salt of 5,10,15,20-tetrakis(1-benzylpyridin-1-ium-4-yl)-21H,23H-porphyrin and its CaII complex By journals.iucr.org Published On :: 2024-05-21 The synthesis, crystallization and characterization of a trifluoromethanesulfonate salt of 5,10,15,20-tetrakis(1-benzylpyridin-1-ium-4-yl)-21H,23H-porphyrin, C68H54N84+·4CF3SO3−·4H2O, 1·OTf, are reported in this work. The reaction between 5,10,15,20-tetrakis(pyridin-4-yl)-21H,23H-porphyrin and benzyl bromide in the presence of 0.1 equiv. of Ca(OH)2 in CH3CN under reflux with an N2 atmosphere and subsequent treatment with silver trifluoromethanesulfonate (AgOTf) salt produced a red–brown solution. This reaction mixture was filtered and the solvent was allowed to evaporate at room temperature for 3 d to give 1·OTf. Crystal structure determination by single-crystal X-ray diffraction (SCXD) revealed that 1·OTf crystallizes in the space group P21/c. The asymmetric unit contains half a porphyrin molecule, two trifluoromethanesulfonate anions and two water molecules of crystallization. The macrocycle of tetrapyrrole moieties is planar and unexpectedly it has coordinated CaII ions in occupational disorder. This CaII ion has only 10% occupancy (C72H61.80Ca0.10F12N8O16S4). The pyridinium rings bonded to methylene groups from porphyrin are located in two different arrangements in almost orthogonal positions between the plane formed by the porphyrin and the pyridinium rings. The crystal structure features cation⋯π interactions between the CaII atom and the π-system of the phenyl ring of neighboring molecules. Both trifluoromethanesulfonate anions are found at the periphery of 1, forming hydrogen bonds with water molecules. Full Article text
por Crystal structure of (1,4,7,10,13,16-hexaoxacyclooctadecane-κ6O)potassium-μ-oxalato-triphenylstannate(IV), the first reported 18-crown-6-stabilized potassium salt of triphenyloxalatostannate By journals.iucr.org Published On :: 2024-08-13 The title complex, (1,4,7,10,13,16-hexaoxacyclooctadecane-1κ6O)(μ-oxalato-1κ2O1,O2:2κ2O1',O2')triphenyl-2κ3C-potassium(I)tin(IV), [KSn(C6H5)3(C2O4)(C12H24O6)] or K[18-Crown-6][(C6H5)3SnO4C2], was synthesized. The complex consists of a potassium cation coordinated to the six oxygen atoms of a crown ether molecule and the two oxygen atoms of the oxalatotriphenylstannate anion. It crystallizes in the monoclinic crystal system within the space group P21. The tin atom is coordinated by one chelating oxalate ligand and three phenyl groups, forming a cis-trigonal–bipyramidal geometry around the tin atom. The cations and anions form ion pairs, linked through carbonyl coordination to the potassium atoms. The crystal structure features C—H⋯O hydrogen bonds between the oxygen atoms of the oxalate group and the hydrogen atoms of the phenyl groups, resulting in an infinite chain structure extending along a-axis direction. The primary inter-chain interactions are van der Waals forces. Full Article text
por The use of ethanol as contrast enhancer in Synchrotron X-ray phase-contrast imaging leads to heterogeneous myocardial tissue shrinkage: a case report By journals.iucr.org Published On :: In this work, we showed that the use of ethanol to increase image contrast when imaging cardiac tissue with synchrotron X-ray phase-contrast imaging (X-PCI) leads to heterogeneous tissue shrinkage, which has an impact on the 3D organization of the myocardium. Full Article text
por (U)SAXS characterization of porous microstructure of chert: insights into organic matter preservation By journals.iucr.org Published On :: 2023-11-15 This study characterizes the microstructure and mineralogy of 132 (ODP sample), 1000 and 1880 million-year-old chert samples. By using ultra-small-angle X-ray scattering (USAXS), wide-angle X-ray scattering and other techniques, the preservation of organic matter (OM) in these samples is studied. The scarce microstructural data reported on chert contrast with many studies addressing porosity evolution in other sedimentary rocks. The aim of this work is to solve the distribution of OM and silica in chert by characterizing samples before and after combustion to pinpoint the OM distribution inside the porous silica matrix. The samples are predominantly composed of alpha quartz and show increasing crystallite sizes up to 33 ± 5 nm (1σ standard deviation or SD). In older samples, low water abundances (∼0.03%) suggest progressive dehydration. (U)SAXS data reveal a porous matrix that evolves over geological time, including, from younger to older samples, (1) a decreasing pore volume down to 1%, (2) greater pore sizes hosting OM, (3) decreasing specific surface area values from younger (9.3 ± 0.1 m2 g−1) to older samples (0.63 ± 0.07 m2 g−1, 1σ SD) and (4) a lower background intensity correlated to decreasing hydrogen abundances. The pore-volume distributions (PVDs) show that pores ranging from 4 to 100 nm accumulate the greater volume fraction of OM. Raman data show aromatic organic clusters up to 20 nm in older samples. Raman and PVD data suggest that OM is located mostly in mesopores. Observed structural changes, silica–OM interactions and the hydrophobicity of the OM could explain the OM preservation in chert. Full Article text
por X-ray standing wave characterization of the strong metal–support interaction in Co/TiOx model catalysts By journals.iucr.org Published On :: 2024-03-31 The strong metal–support interaction (SMSI) is a phenomenon observed in supported metal catalyst systems in which reducible metal oxide supports can form overlayers over the surface of active metal nanoparticles (NPs) under a hydrogen (H2) environment at elevated temperatures. SMSI has been shown to affect catalyst performance in many reactions by changing the type and number of active sites on the catalyst surface. Laboratory methods for the analysis of SMSI at the nanoparticle-ensemble level are lacking and mostly based on indirect evidence, such as gas chemisorption. Here, we demonstrate the possibility to detect and characterize SMSIs in Co/TiOx model catalysts using the laboratory X-ray standing wave (XSW) technique for a large ensemble of NPs at the bulk scale. We designed a thermally stable MoNx/SiNx periodic multilayer to retain XSW generation after reduction with H2 gas at 600°C. The model catalyst system was synthesized here by deposition of a thin TiOx layer on top of the periodic multilayer, followed by Co NP deposition via spare ablation. A partial encapsulation of Co NPs by TiOx was identified by analyzing the change in Ti atomic distribution. This novel methodological approach can be extended to observe surface restructuring of model catalysts in situ at high temperature (up to 1000°C) and pressure (≤3 mbar), and can also be relevant for fundamental studies in the thermal stability of membranes, as well as metallurgy. Full Article text
por Neural network analysis of neutron and X-ray reflectivity data incorporating prior knowledge By journals.iucr.org Published On :: 2024-03-31 Due to the ambiguity related to the lack of phase information, determining the physical parameters of multilayer thin films from measured neutron and X-ray reflectivity curves is, on a fundamental level, an underdetermined inverse problem. This ambiguity poses limitations on standard neural networks, constraining the range and number of considered parameters in previous machine learning solutions. To overcome this challenge, a novel training procedure has been designed which incorporates dynamic prior boundaries for each physical parameter as additional inputs to the neural network. In this manner, the neural network can be trained simultaneously on all well-posed subintervals of a larger parameter space in which the inverse problem is underdetermined. During inference, users can flexibly input their own prior knowledge about the physical system to constrain the neural network prediction to distinct target subintervals in the parameter space. The effectiveness of the method is demonstrated in various scenarios, including multilayer structures with a box model parameterization and a physics-inspired special parameterization of the scattering length density profile for a multilayer structure. In contrast to previous methods, this approach scales favourably when increasing the complexity of the inverse problem, working properly even for a five-layer multilayer model and a periodic multilayer model with up to 17 open parameters. Full Article text
por Revealing nanoscale sorption mechanisms of gases in a highly porous silica aerogel By journals.iucr.org Published On :: 2024-08-19 Geological formations provide a promising environment for the long-term and short-term storage of gases, including carbon dioxide, hydrogen and hydrocarbons, controlled by the rock-specific small-scale pore structure. This study investigates the nanoscale structure and gas uptake in a highly porous silica aerogel (a synthetic proxy for natural rocks) using transmission electron microscopy, X-ray diffraction, and small-angle and ultra-small-angle neutron scattering with a tracer of deuterated methane (CD4) at pressures up to 1000 bar. The results show that the adsorption of CD4 in the porous silica matrix is scale dependent. The pore space of the silica aerogel is fully accessible to the invading gas, which quickly equilibrates with the external pressure and shows no condensation on the sub-nanometre scale. In the 2.5–50 nm pore size region a classical two-phase adsorption behaviour is observed. The structure of the aerogel returns to its original state after the CD4 pressure has been released. Full Article text
por 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
por Paymentology partners with Zand Bank to support fintech growth in UAE By thepaypers.com Published On :: Tue, 12 Nov 2024 14:08:00 +0100 Paymentology has entered into a referral partnership with... Full Article
por The Global Payments and Fintech Trends Report 2024 By thepaypers.com Published On :: Fri, 09 Feb 2024 11:39:00 +0100 The inaugural edition of the Global Payments and Fintech Trends Report offers a comprehensive overview of the key trends in fintech and payments for the year 2024 and beyond. Full Article
por Emerging Technologies and Trends in Identity Verification, KYC, and KYB Report 2024 By thepaypers.com Published On :: Thu, 16 May 2024 09:00:00 +0100 The inaugural edition of the Emerging Technologies and Trends in Identity Verification (IDV), KYC, and KYB Report 2024 offers a comprehensive overview of the key technology trends and best practices in digital onboarding for consumers and businesses in 2024. Full Article
por Fintech for Marketplaces and Platforms Report 2024 By thepaypers.com Published On :: Tue, 28 May 2024 07:24:00 +0100 The 1st edition of the Fintech for Marketplaces and Platforms Report covers essential ecommerce trends and future perspectives. Full Article
por Unlocking the Potential of A2A Payments Report 2024 By thepaypers.com Published On :: Wed, 03 Jul 2024 14:44:00 +0100 The first edition of the Unlocking the Potential of A2A Payments Report 2024 provides the latest insights into the A2A space. Full Article
por Embedded Finance and Banking-as-a-Service Report 2024 By thepaypers.com Published On :: Mon, 05 Aug 2024 11:52:00 +0100 Unlock unparalleled insights into the transformative world of Embedded Finance and Banking-as-a-Service (BaaS) with The Paypers' latest report. Dive deep into essential business models, key players, and the latest trends reshaping industries with our comprehensive guide, curated by industry experts and leading companies. Full Article
por Fraud Prevention in Ecommerce Report 2024-2025 By thepaypers.com Published On :: Tue, 01 Oct 2024 10:01:00 +0100 The 6th edition of the Fraud Prevention in Ecommerce Report provides a thorough overview of the global fraud ecosystem. Full Article
por Towards Seamless Payment Interoperability – Thunes Report By thepaypers.com Published On :: Fri, 11 Oct 2024 09:24:00 +0100 ‘The Road Ahead: Towards Seamless Payments Interoperability’, an eBook from Thunes, Visa, and The Paypers, explores how payments interoperability is reshaping the future of cross-border transactions. Full Article
por Next-Gen Tech to Detect Fraud and Financial Crime Report 2024 By thepaypers.com Published On :: Tue, 22 Oct 2024 08:16:00 +0100 The Next-Gen Technologies to Detect Fraud and Financial Crime Report 2024 highlights how banks, fintechs, and PSPs leverage AI and emerging tech to detect and combat advanced fraud. Full Article
por Thunes partners with Papara to support cross-border payments in Turkey By thepaypers.com Published On :: Mon, 11 Nov 2024 13:29:00 +0100 Thunes, a global cross-border payments platform, has announced a... Full Article
por October Report Highlights Big Gains in Crypto Mining Efficiency and Expansion By www.streetwisereports.com Published On :: Wed, 06 Nov 2024 00:00:00 PST Source: Streetwise Reports 11/06/2024 Terawulf Inc. (WULF:NASDAQ) has reported its October 2024 production and operations. Read more about the companys mining efficiency gains, expansion plans, and high-performance computing initiatives.Terawulf Inc. (WULF:NASDAQ) has reported its October 2024 production and operations. The report included significant advancements in self-mining with an operational capacity reaching 8.1 exahash per second (EH/s). This marks a 62% increase from the prior year. The company mined a total of 150 bitcoins during the month, averaging approximately 4.8 bitcoins per day, at a power cost of US$36,789 per bitcoin mined or about US$0.048 per kWh (kilowatt-hour). To improve efficiency, TeraWulf continued its miner refresh program at its Lake Mariner facility, replacing older models with upgraded S19 XP miners following its sale of interest in the Nautilus Cryptomine facility, which enabled additional hardware acquisitions. Focusing on high-performance computing (HPC) infrastructure, TeraWulf's aim is to establish 72.5 MW HPC hosting capacity at Lake Mariner by Q2 2025. October's operational hash rate averaged 6.8 EH/s, with adjustments made for demand response events and performance optimization measures to enhance profitability. Construction on the company's 20 MW HPC hosting facility, CB-1, remains on schedule for Q1 2025, and a larger 50 MW HPC facility, CB-2, is expected by Q2 2025. The recent sale of TeraWulf's equity interest in Nautilus and new financing through convertible notes are anticipated to support these growth initiatives. Sean Farrell, Senior Vice President of Operations at TeraWulf, explained in the press release, "October marked another productive month, with TeraWulf mining 150 bitcoin and sustaining an average daily production of around 5 bitcoin . . . In line with our previously outlined plans, we are accelerating the transition to more efficient mining hardware by replacing older miners at Lake Mariner with S19 XP models. We are also working closely with Bitmain's warranty department on a recovery plan to repair and replace 1.5 EH of mining equipment with a target completion by the end of the year. Furthermore, we have established a dedicated Business Development and Performance Optimization team focused on integrating advanced IT and software solutions to improve our operational hash rate and overall efficiency. Building 5, which has been designed to handle higher heat exhaust of the latest generation miners, remains on track to be operational in Q1 2025." Why Crypto Mining? The cryptocurrency mining sector has seen recent momentum, bolstered by the U.S. election results and the evolving landscape for Bitcoin. As Benzinga reported on November 6, bitcoin mining stocks experienced notable gains following the U.S. presidential election, which led to Bitcoin reaching record highs. The outcome was anticipated to benefit U.S.-focused mining companies as pro-crypto policies, including a preference for domestic bitcoin production, gained prominence. Benzinga noted that Trump had previously expressed support for more bitcoin mining within the U.S., a stance that influenced broader market optimism in the days following his election. On November 4, Yahoo! Finance highlighted the growing trend among Bitcoin miners to integrate artificial intelligence (AI) to power a "new industrial revolution." As described by Rob Nelson, who emphasized the impact of cryptocurrency mining as a vehicle for both economic and technological change. This trend has driven miners to secure deals within the AI sector, given the synergies in computational power required for both cryptocurrency and AI initiatives. Nelson projected that this cross-industry expansion could have far-reaching effects, creating value for both miners and AI-focused enterprises. Additionally, a November 6 report from Time explored the significance of the recent Presidential election outcome for the crypto industry's future regulatory environment. According to Time, Trump's support for the industry included ambitions to boost the country's bitcoin mining footprint, which aligned with crypto PACs' efforts to secure pro-crypto candidates. The article reported that these advocacy groups saw the election as an opportunity to reshape crypto regulation and encourage growth in U.S.-based bitcoin mining. TeraWulf's Catalysts TeraWulf's recent initiatives set a foundation for further growth and operational efficiency. According to the company's investor presentation, the sale of its 25% equity interest in the Nautilus facility enhances liquidity. This enables TeraWulf to reinvest in its flagship Lake Mariner site for both HPC and AI expansion. The transaction also reduces exposure to the expiring Nautilus 2¢ power contract by 2027, positioning the company to benefit from projected power price increases at Lake Mariner. This strategic realignment is anticipated to improve fleet efficiency, with an upgraded mining fleet targeting 13 EH/s by Q1 2025, supported by the deployment of next-gen S21 Pro miners. What Experts Are Saying... On November 5, 2024, Roth MKM analyst Darren Aftahi assigned TeraWulf a "Buy" rating and set a price target of US$7.50. Roth highlighted optimism around the company's expansion and potential in high-performance computing (HPC) and bitcoin mining. Roth noted that TeraWulf's planned 72.5 MW of HPC capacity by Q2 2025 could generate annualized revenue of approximately US$90 million, with over US$60 million in profit. [OWNERSHIP_CHART-11184] The report highlighted the completion of TeraWulf's initial 2.5 MW HPC project and its upcoming 20 MW facility, which remains on track for Q1 2025. Roth analysts pointed to the operational progress at TeraWulf's Lake Mariner facility, emphasizing the company's improvements in mining efficiency with new S19 XP models, which brought its machine efficiency to 22 J/TH. Ownership and Share Structure According to Refinitiv, management and insiders hold 6.67% of TeraWulf. Of them, Co-founder, COO, and CTO Nazar M. Khan holds the most, with 4.43%. Strategic investors hold 21.37%. Of them, Riesling Power LLC holds the most at 5.23%, Baryshore Capital LLC holds 4.77%, Revolve Capital LLC has 4.67%, Opportunity Four of Parabolic Ventures owns 2.46%, and Lake Harriet Holdings LLC has 1.90%. Institutions have 45.11%. The largest holders there are The Vanguard Group at 6.12%, BlackRock Instituional Trust with 4.22%, Two Sigma Investments LP at 2.28%, Beryl Capital Management LLC holds 1.74%, and Geode Capital Management LLC has 1.66%. The rest is retail.TeraWulf has a market cap of US$2,375.93 million and 275.29 million free float shares. Their 52-week range is US$ 0.8911 - 7.28. Sign up for our FREE newsletter at: www.streetwisereports.com/get-newsImportant Disclosures:1) James Guttman wrote this article for Streetwise Reports LLC and provides services to Streetwise Reports as an employee. 2) This article does not constitute investment advice and is not a solicitation for any investment. Streetwise Reports does not render general or specific investment advice and the information on Streetwise Reports should not be considered a recommendation to buy or sell any security. Each reader is encouraged to consult with his or her personal financial adviser and perform their own comprehensive investment research. By opening this page, each reader accepts and agrees to Streetwise Reports' terms of use and full legal disclaimer. Streetwise Reports does not endorse or recommend the business, products, services or securities of any company. For additional disclosures, please click here. ( Companies Mentioned: WULF:NASDAQ, ) Full Article
por Adyen supports Tap-to-Pay on iPhone in more European markets By thepaypers.com Published On :: Wed, 30 Oct 2024 14:50:00 +0100 Global financial platform Adyen has announced that it enabled... Full Article
por New Report Finds Major US Metro Areas, Greater Los Angeles Among Them, Are More Segregated Now Than 30 Years Ago By www.scpr.org Published On :: Wed, 30 Jun 2021 09:31:22 -0700 People rest while riding a Los Angeles Metro Rail train amid the coronavirus pandemic on April 1, 2020 in Los Angeles, California.; Credit: Mario Tama/Getty Images AirTalkDespite the racial reckoning going on in America right now, and despite the fact that attitudes towards race, inclusion and representation are different now than they were 30 years ago, new research from UC Berkeley shows that a large majority of American metro areas are more segregated now than they were in 1990. The new report from Berkeley’s Institute covers a number of topic areas, but among the key findings were from the national segregation report component of the project, which found Los Angeles to be the sixth-most segregated metro area with more than 200,000 people. Today on AirTalk, we’ll talk with the lead researcher on the new report and a local historian to talk about how we see the findings of the report play out in Southern California. Guests: Stephen Menendian, assistant director and director of research at the Othering & Belonging Institute at UC Berkeley, which works to identify and eliminate the barriers to an inclusive, just, and sustainable society in order to create transformative change; he tweets @SMenendian Eric Avila, professor of history, urban planning, and Chicano/a studies at UCLA This content is from Southern California Public Radio. View the original story at SCPR.org. Full Article
por New way for bridges to withstand earthquakes: Support column design By news.science360.gov Published On :: 2019-09-04T07:00:00Z Full Text:Bridges make travel faster and more convenient, but, in an earthquake, these structures are subject to forces that can cause extensive damage and make them unsafe. Now civil and environmental engineer Petros Sideris of Texas A&M University is leading a National Science Foundation (NSF)-funded research project to investigate the performance of hybrid sliding-rocking (HSR) columns. HSR columns provide the same support as conventional bridge infrastructure columns but are more earthquake-resistant. HSR columns are a series of individual concrete segments held together by steel cables that allow for controlled sliding and rocking. This allows the columns to shift without damage, while post-tensioning strands ensure that at the end of an earthquake the columns are pushed back to their original position. Conventional bridges are cast-in-place monolithic concrete elements that are strong but inflexible. Structural damage in these bridge columns, typically caused by a natural disaster, often forces a bridge to close until repairs are completed. But bridges with HSR columns can withstand large earthquakes with minimal damage and require minor repairs, likely without bridge closures. Such infrastructure helps with post-disaster response and recovery and can save thousands in taxpayer dollars. In an earthquake, HSR columns provide "multiple advantages to the public," Sideris said. "By preventing bridge damage, we can maintain access to affected areas immediately after an event for response teams to be easily deployed, and help affected communities recover faster. In mitigating losses related to post-event bridge repairs and bridge closures, more funds can be potentially directed to supporting the recovery of the affected communities." According to Joy Pauschke, NSF program director for natural hazards engineering, "NSF invests in fundamental engineering research so that, in the future, the nation's infrastructure can be more resilient to earthquakes, hurricanes, and other forces of nature."Image credit: Texas A&M University Full Article
por Only the Mobile Enterprise will Survive: 10 Practical Strategies for Supporting a Next-Generation Mobile Workforce By www.itsecurity.com Published On :: Thu, 12 Nov 2009 00:04:08 +0000 WHEN: Wed, November 18Time: 10am PT / 1pm ET Join Now!SPONSORED BY: Nortel and AT&TJoin leading mobility experts to hear why only the mobile enterprise will survive! Join Now!Why the mobile ... Full Article
por Zero Day Response: Strategies for the Newest Innovation in Corporate Defense By www.itsecurity.com Published On :: Fri, 26 Mar 2010 23:04:02 +0000 On-Demand Webinar > Watch Now!>>SPONSORED BY: TripwireResearch shows that over a third of organizations are not prepared for breaches while the average cost per breach in 2009 was $6.7 millio... Full Article
por Administrative Assistant I - Child Support By www.governmentjobs.com Published On :: Fri, 08 Nov 2024 00:58:25 GMT Catawba County Social Services is committed to making living better through serving children and families with multiple and complex needs. We are seeking an Administrative Assistant I for our Child Support unit who shares our common values: Doing what’s right:Provide the utmost Child Support Services by always providing excellent customer service to internal and external customers.Doing what matters most:Advocating for children to receive the financial stability that they deserve and providing the best customer service to all that we serve.Doing it together:Building relationships with all parties involved as well as stakeholders to obtain an order of support or to enforce an order support, so that children can receive the financial support they need and deserve.Doing it well:Striving for excellence in meeting all mandated standards in a fast – paced rewarding environment that ultimately seeks to provide financial stability for children, parents and caretakers. Full Article
por Bill Cosby Urges Howard University To Support Phylicia Rashad's Freedom Of Speech By www.scpr.org Published On :: Mon, 05 Jul 2021 12:40:12 -0700 Bill Cosby gestures outside his home in Elkins Park, Pa., on June 30, 2021, after being released from prison when the Pennsylvania's supreme court overturned his sexual assault conviction. Cosby expressed support for former TV co-star Phylicia Rashad's freedom of speech after she defended him in a tweet.; Credit: Matt Rourke/AP Elizabeth Blair | NPRBill Cosby called on Howard University to support former co-star Phylicia Rashad's freedom of speech after she expressed support for him when his sexual assault conviction was overturned. In a statement, Cosby also lashed out at the media, comparing journalists to the rioters who stormed the Capitol in January. "Howard University you must support ones Freedom of Speech (Ms. Rashad), which is taught or suppose to be taught everyday at that renowned law school, which resides on your campus," Cosby said in a statement provided to NPR by his spokesman Andrew Wyatt. "This mainstream media has become the Insurrectionists, who stormed the Capitol," Cosby continued in his statement. "Those same Media Insurrectionists are trying to demolish the Constitution of these United State of America on this Independence Day." Cosby concluded by saying, "WE THE PEOPLE STAND IN SUPPORT OF MS. PHYLICIA RASHAD" in all caps. Cosby's support of Rashad comes after the actress, who played his TV wife in The Cosby Show, defended the comedian in a tweet. Cosby was released from prison last week when the Pennsylvania Supreme Court vacated his sexual assault conviction on the grounds that his due process rights were violated. "FINALLY!!!! A terrible wrong is being righted- a miscarriage of justice is corrected!" Rashad said last week. The tweet has since been removed and Rashad later backpedaled, writing that she "fully support survivors of sexual assault coming forward." She also sent a letter of apology to Howard students Many Howard alumni had expressed disappointment at the remarks. Howard University responded with its own tweet, stating that Dean Rashad's "initial tweet lacked sensitivity towards survivors of sexual assault." Rashad was recently named Dean of Howard University's Chadwick Boseman College of Fine Arts. Rashad, an acclaimed stage and screen artist, graduated from Howard magna cum laude in 1970 with a bachelor's in fine arts. She returned as a guest lecturer and adjunct faculty member. In a statement announcing her appointment in May, Provost Anthony K. Wutoh said Rashad's "passion for the arts and student success makes her a perfect fit for this role." One of the students Rashad mentored at Howard was the late actor Chadwick Boseman, for whom the school's College of Fine Arts is named. Copyright 2021 NPR. To see more, visit https://www.npr.org. This content is from Southern California Public Radio. View the original story at SCPR.org. Full Article
por Catawba County Public Health reports restaurant patrons appreciate new "smoke-free" law By www.catawbacountync.gov Published On :: Thu, 7 Jan 2010 00:00:00 EST As of January 2, 2010 restaurants, bars and other businesses that serve food and drink in Catawba County became smoke-free. Many health advocates and local residents are pleased that they can now enjoy a healthier dining experience. The ban is a result of a new law that prohibits smoking in all restaurants and bars across North Carolina. Full Article News Release FYI Please Choose
por Important milestones begin in 2011 property revaluation in Catawba County By www.catawbacountync.gov Published On :: Tue, 7 Sep 2010 12:58:00 EST The final stages of the 2011 property revaluation process in Catawba County have begun with the presentation of the proposed 2011 Schedule of Values to the Board of Commissioners, and will continue into November, when property owners will receive notice of the new value of their property, and into December and early 2011 when the appeal process begins. Full Article News Release FYI Public Notice
por Planning to meet an emergency is especially important for persons with special needs By www.catawbacountync.gov Published On :: Fri, 24 Sep 2010 08:39:00 EST As it continues to note National Emergency Preparedness Month, Catawba County Emergency Services reminds citizens who have family members with special needs, and caregivers of those with special needs, that it�s very important to be prepared in advance to help those with special needs cope with an emergency or disastrous situation. Full Article News Release FYI Please Choose
por Catawba County Children's Agenda Planning Committee releases report after two years of gathering information. By www.catawbacountync.gov Published On :: Thu, 12 May 2011 13:33:00 EST The committee compiled existing information about the status of children in the county. It also held public meetings and surveyed members of the public about their priorities and ideas. The committee found that most children in the county are well-cared for, but that a substantial number are falling through the cracks. A major cause of concern is the large number of children living in poverty. Full Article News Release FYI Please Choose